12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, 12-HHT is a BLT2 receptor agonist
The production of LTB4 and expression of BLT1 by human tissues are largely limited to bone marrow-derived cells such as the neutrophil, eosinophil, mast cell, and various types of  lymphocytes and accordingly are regarded primarily as contributing to the many human defensive and pathological (ulcerative colitis, arthritis, asthma, etc.) inflammatory responses which are mediated by these cell types. Drugs that inhibit LTB4 production or binding to BLT1 are in use or development for the latter diseases.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, 12-HHT is a BLT2 receptor agonist
In contrast, the production of 12-HH2 and expression of BLT2 receptors by human tissues is far wider and more robust than that of the LTB4/BLT2 receptor axis. Recent studies indicate that the role(s) of the 12-HHT/BLT2 receptor axis in human physiology and pathology may be very different than those of the LTB4/BLT1 axis.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, Recent studies on 12-HHT/BLT2 receptor activities, Inflammation and allergy
12-HHT stimulates chemotactic responses in mouse bone marrow mast cells, which naturally express BLT2 receptors, as well as in Chinese hamster ovary cells made to express these receptors by transfection. These findings suggest that the 12-HHT/BLT2 receptor pathway may support the pro-inflammatory (i.e. chemotactic) actions of the LTB4/BLT1 pathway.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, Recent studies on 12-HHT/BLT2 receptor activities, Inflammation and allergy
On the other hand, the immortalized human skin cell line HaCaT expresses BLT2 receptors and responds to ultraviolet B (UVB) radiation by generating toxic reactive oxygen species which in turn cause the HaCaT cells to die by activating apoptotic pathways in a BLT2 receptor-dependent reaction. Topical treatment of mouse skin with a BLT2 receptor antagonist, LY255283, protects against UVB radiation-induced apoptosis and BLT2-overexpressing transgenic mice exhibited significantly more extensive skin apoptosis in response to UVB irradiation. Furthermore, 12-HHT inhibits HaCaT cells from synthesizing interleukin-6 (IL-6), a pro-inflammatory cytokine associated with cutaneous inflammation, in response to UVB radiation.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, Recent studies on 12-HHT/BLT2 receptor activities, Inflammation and allergy
These results suggest that the 12-HHT/BLT2 axis can act to suppress inflammation by promoting the orderly death of damaged cells and blocking IL-6 production. Opposition between the pro-inflammatory LTB4/BLT1 and anti-inflammatory actions of the 12-HHT/BLT2 axes occurs in another setting.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, Recent studies on 12-HHT/BLT2 receptor activities, Inflammation and allergy
In a mice model of ovalbumin-induced allergic airway disease, 12-HHT and its companion cyclooxygenase metabolites, Prostaglandin E2 and Prostaglandin D2, but not 12 other lipoxygenase or cycloxygenase metabolites, showed a statistically significantly increase in bronchoalveolar lavage fluid levels after intratracheal ovalbumin challenge; after this challenge, only 12-HHT, among the monitored BLT2 receptor-activating ligands (LTB4, the 12(S) stereoisomer of 12-HETE, and 15(S)-HETE) attained levels capable of activating BLT2 receptors. Also, BLT2 knockout mice exhibited a greatly enhanced response to ovalabumin challenge.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, Recent studies on 12-HHT/BLT2 receptor activities, Inflammation and allergy
Finally, BLT2 receptor expression was significantly reduced in allergy-regulating CD4+ T cells from patients with asthma compared to healthy control subjects. Unlike LTB4 and its BLT1 receptor, which are implicated in contributing to allergen-based airway disease in mice and humans, 12-HHT and its BLT2 receptor appear to suppress this disease in mice and may do so in humans. While further studies to probe the role of the 12-HHT/BLT2 axis in human inflammatory and allergic diseases, the current studies indicate that 12-HHT, acting through BLT2, may serve to promote or limit, inflammatory and to promote allergic responses.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, Recent studies on 12-HHT/BLT2 receptor activities, Wound healing
High dose aspirin treatment (aspirin, at these doses, inhibits cyclooxygenases-1 and -2 to block their production of 12-HHT), thromboxane synthase knockout, and BLT2 receptor knockout but not TXA2 receptor knockout impair keratinocyte-based re-epithelialization and thereby closure of experimentally induced wounds in mice while a synthetic BLT2 receptor agonist accelerats wound closure not only in this mouse model but also in the db/db mouse model of obesity, diabetes, and dyslipidemia due to leptin receptor deficiency. 12-HHT accumulated in the wounds of the former mouse model.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, Recent studies on 12-HHT/BLT2 receptor activities, Wound healing
Companion studies using an in vitro scratch test assay indicated that 12-HHT stimulated human and mouse keratinocyte migration by a BLT2 receptor-dependent mechanism that involved the production of tumor necrosis factor α and metalloproteinases. These results indicate that the 12-HHT/BLT2 receptor axis is a critical contributor to wound healing in mice and possibly humans. The axis operates by recruiting the movement of keratinocytes to close the wound. This mechanism may underlie the suppression of wound healing that accompanies the high dose intake of aspirin and, based on mouse studies, other non-steroidal anti-inflammatory agents (NSAID) in humans. Synthetic BLT2 agonists may be useful for speeding the healing of chronic ulcerative wounds, particularly in patients with, for example diabetics, that have impaired wound healing.


12-Hydroxyheptadecatrienoic acid, Activities and clinical significance, Cancer
A large number of studies have associated BLT2 and, directly or by assumption, 12-HHT in the survival, growth, and/or spread of various human cancers. See 'Leukotriene B4 receptor 2 for the associations of BLT2 and/or 12-HHT with stimulating the malignant behavior of prostate cancer, urinary bladder cancer, breast cancer, thyroid gland follicular carcinoma, kidney renal cell carcinoma, bladder transitional cell carcinoma, esophageal cancer, pancreatic cancer, and colon cancer.


12-O-Tetradecanoylphorbol-13-acetate
12-O-Tetradecanoylphorbol-13-acetate (TPA), also commonly known as tetradecanoylphorbol acetate, tetradecanoyl phorbol acetate, and phorbol 12-myristate 13-acetate (PMA), is a diester of phorbol and a potent tumor promoter often employed in biomedical research to activate the signal transduction enzyme protein kinase C (PKC). The effects of TPA on PKC result from its similarity to one of the natural activators of classic PKC isoforms, diacylglycerol. TPA is a small molecule drug.


12-O-Tetradecanoylphorbol-13-acetate
In ROS biology, superoxide was identified as the major reactive oxygen species induced by TPA/PMA but not by ionomycin in mouse macrophages. Thus, TPA/PMA has been routinely used as an inducer for endogenous superoxide production.


12-O-Tetradecanoylphorbol-13-acetate
TPA is also being studied as a drug in the treatment of hematologic cancer


12-O-Tetradecanoylphorbol-13-acetate
TPA has a specific use in cancer diagnostics as a B-cell specific mitogen in cytogenetic testing. To view the chromosomes, a cytogenetic test requires dividing cells. TPA is used to stimulate division of B-cells during cytogenetic diagnosis of B-cell cancers such as chronic lymphocytic leukemia.


12-O-Tetradecanoylphorbol-13-acetate
TPA is also commonly used together with ionomycin to stimulate T-cell activation, proliferation, and cytokine production, and is used in protocols for intracellular staining of these cytokines.


12-O-Tetradecanoylphorbol-13-acetate
TPA induces KSHV reactivation in PEL cell cultures via stimulation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway. The pathway involves the activation of the early-immediate viral protein RTA that contributes to the activation of the lytic cycle.


12-O-Tetradecanoylphorbol-13-acetate
TPA was first found in  the croton plant, a shrub found in Southeast Asia, exposure to which provokes a poison ivy-like rash. It underwent a phase 1 clinical trial.


12-String Blues
12-String Blues (sub-titled Live at the Scholar), is the first album by American guitarist Leo Kottke, released in 1969.


12-String Blues, History
The majority of the album was recorded live at The Scholar, a Minneapolis coffee house (formerly known as the Ten O'Clock Scholar in another location) that had also featured Bob Dylan, Spider John Koerner and Simon & Garfunkel early in their careers. Three of the instrumentals were recorded in a studio. The LP record was a limited edition of 1000 copies, on the Minneapolis West Bank-based Oblivion Records (apparently this is their only album), and it has not been reprinted and/or re-issued on CD. Publishing for the songs was by Symposium Music, same as the publishing and record label for Kottke's third LP. The Oblivion catalog number, "obl-s1," also indicates a possible connection with Symposium.


12-String Blues, History
Most of the songs on the album were re-recorded for Kottke's album Circle Round The Sun.


12-String Blues, Track listing (with Kottke's notes)
All tracks are written by Leo Kottke, except where noted.


12-bit computing
In computer architecture, 12-bit integers, memory addresses, or other data units are those that are  12 bits (1.5 octets) wide. Also, 12-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size.


12-bit computing
Possibly the best-known 12-bit CPU is the PDP-8 and its relatives, such as the Intersil 6100 microprocessor produced in various incarnations from August 1963 to mid-1990. Many analog to digital converters (ADCs) have a 12-bit resolution. Some PIC microcontrollers use a 12-bit word size.


12-bit computing
12 binary digits, or 3 nibbles (a 'tribble'), have 4096 (10000 octal, 1000 hexadecimal) distinct combinations. Hence, a microprocessor with  12-bit memory addresses can directly access 4096 words (4 Kw) of word-addressable memory. At a time when six-bit character codes were common a 12-bit word, which could hold two characters, was a convenient size. IBM System/360 instruction formats use a 12-bit displacement field which, added to the contents of a base register, can address 4096 bytes of memory.


12-car rally
A 12-car rally is a type of car rally, often run by motor clubs as a simple and strictly amateur form of the sport.


12-car rally
12-car rallies are run to Navigational Rally rules, which are based on navigational skills rather than speed, and with usually a notable social element too. In the United Kingdom, the rules for 12-cars are governed by the Motor Sports Association UK (MSA) and are as follows:


12-channel carrier system
In the U.S. telephone network, the 12-channel carrier system was an early frequency-division multiplexing system standard, used to carry multiple telephone calls on a single twisted pair of wires, mostly for short to medium distances. In this system twelve voice channels are multiplexed in a high frequency carrier and passed through a balanced pair trunk line similar to those used for individual voice frequency connections. The original system is obsolete today, but the multiplexing of voice channels in units of 12 or 24 channels in modern digital trunk lines such as T-1 is a legacy of the system.


12-channel carrier system, History
The twelve channel scheme was first devised in the early 1930s to provide a line spectrum covering 60 to 108 kHz for the Type J Carrier Telephone System, an equivalent four wire (on two wire facilities) open wire carrier that was used almost exclusively for interstate long haul toll telephony. This became the basic building block, the "channel group", for all succeeding long haul systems, such as Type K and all the Type L systems into the late 1970s. All long haul "channel groups" used the single-sideband/suppressed carrier heterodyne scheme that was produced by a Western Electric Type A-1 through A-6 channel bank.


12-channel carrier system, History
The twelve channel scheme, in order to maintain some bandwidth and routing compatibility, was carried through to the short haul carriers, as well, as they started developing to eliminate voice band open wire trunk lines in the 1950s. The Bell System vacuum-tube driven N-1 Carrier of the early 1950s was the most used twelve channel carrier system, using double sideband/unsuppressed carrier operation which didn't need network timebase synchronization to maintain frequency accuracy.


12-channel carrier system, History
N-2 was similar in heterodyning scheme, but in discrete transistorized "plug-in unit" architecture, while N3 used the same frequency plan but a scheme of using single sideband with a different voice channel on each side of the carrier, a technique first seen on the 16 channel Type "O" open wire short haul carrier of the 1950s. This doubled the capacity to 24 channels, the same as a basic digital Type T PCM carrier introduced in the late 1950s, which became the now-ubiquitous "T-1" of the digital world.


12-channel carrier system, History
Repeaters were spaced approximately 6 miles (10 km) apart, depending on wire gauge. With few exceptions, N-carriers used 19 gage unloaded toll pairs in two-wire operation. Each repeater either received from both directions at a low frequency band and sent in both directions at a higher band, or vice versa. This frequency frogging allowed equivalent four-wire operation on a single cable pair in two-wire operation.


12-channel carrier system, History
During the period when Type N-1 was in widespread use, Lenkurt Corporation, owned and controlled by General Telephone, fielded a variant competitor, the Type BN. BN used the same pairs and repeaters as did the Bell N-CXR, but used four channel "groups," lower single-sideband heterodyning, and 24 channels per carrier, as later seen on Western Electric's Type N-3. Type BN was used at times by Bell Operating Companies after the 1956 Hush-a-phone Decision of the US Supreme Court, a landmark case which challenged AT&T's "benign monopoly" of US telephone equipment industry.


12-channel carrier system, History
Part of this settlement was for AT&T's Bell Operating Companies to buy and use small amounts of Lenkurt and Collins microwave and carrier systems. In California, Type BN was used almost exclusively to provide trunk and private line connections between Pacific Tel. & Tel. toll offices and local General Telephone end offices.


12-cm Kanone M 80
The 12 cm Kanone M 80 was a light siege gun used by Austria-Hungary during World War I. Designed to replace the M 61 series of siege guns the M 80 family of siege guns offered greater range and armor penetration than the older guns. The proven steel-bronze was used for the barrel and the iron carriage lacked any system to absorb recoil other than the traditional recoil wedges placed underneath and behind the wheels of the carriage. These wedges helped to absorb the recoil force and encouraged the wheels to run forward to bring the gun back into battery.


12-cm Kanone M 80
Generally a wooden firing platform was constructed for these guns in action to provide a level and smooth surface. Shortly after these guns were adopted a hydraulic recoil cylinder was adapted to absorb the recoil forces. It was attached to the underside of the carriage and the firing platform. For transport the barrel was removed from the carriage by a crane and carried separately.


12-cm Kanone M 80
While designed to penetrate the walls of fortifications the 12 cm siege gun was no longer useful against modern armored fortresses by the outbreak of World War I and its combination of long-range and light weight saw many in the field to fill the need for long-range artillery.


12-hour clock
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. (from Latin ante meridiem, translating to "before midday") and p.m. (from Latin post meridiem, translating to "after midday"). Each period consists of 12 hours numbered: 12 (acting as 0), 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11.


12-hour clock
The daily cycle starts at 12 midnight (usually indicated as 12:00 a.m.), runs through 12 noon (usually indicated as 12:00 p.m.), and continues until just before midnight at the end of the day. The 12-hour clock was developed from the second millennium BC and reached its modern form in the 16th century AD.


12-hour clock
The 12-hour time convention is common in several English-speaking nations and former British colonies, as well as a few other countries. It is an example of a duodecimal system.


12-hour clock, History and use
The natural day-and-night division of a calendar day forms the fundamental basis as to why each day is split into two cycles. Originally there were two cycles: one cycle which could be tracked by the position of the Sun (day), followed by one cycle which could be tracked by the Moon and stars (night). This eventually evolved into the two 12-hour periods which are used today, one called "a.m." starting at midnight and another called "p.m." starting at noon. Noon itself is rarely abbreviated today; but if it is, it is denoted "m."


12-hour clock, History and use
The 12-hour clock can be traced back as far as Mesopotamia and ancient Egypt. Both an Egyptian sundial for daytime use and an Egyptian water clock for night-time use were found in the tomb of Pharaoh Amenhotep I. Dating to c. 1500 BC, these clocks divided their respective times of use into 12 hours each.


12-hour clock, History and use
The Romans also used a 12-hour clock: daylight was divided into 12 equal hours (thus hours having varying length throughout the year) and the night was divided into four watches.


12-hour clock, History and use
The first mechanical clocks in the 14th century, if they had dials at all, showed all 24 hours using the 24-hour analog dial, influenced by astronomers' familiarity with the astrolabe and sundial and by their desire to model the Earth's apparent motion around the Sun. In Northern Europe these dials generally used the 12-hour numbering scheme in Roman numerals but showed both a.m. and p.m. periods in sequence. This is known as the double-XII system and can be seen on many surviving clock faces, such as those at Wells and Exeter.


12-hour clock, History and use
Elsewhere in Europe, numbering was more likely to be based on the 24-hour system (I to XXIV). The 12-hour clock was used throughout the British empire.


12-hour clock, History and use
During the 15th and 16th centuries, the 12-hour analog dial and time system gradually became established as standard throughout Northern Europe for general public use. The 24-hour analog dial was reserved for more specialized applications, such as astronomical clocks and chronometers.


12-hour clock, History and use
Most analog clocks and watches today use the 12-hour dial, on which the shorter hour hand rotates once every 12 hours and twice in one day. Some analog clock dials have an inner ring of numbers along with the standard 1-to-12 numbered ring. The number 12 is paired either with a 00 or a 24, while the numbers 1 through 11 are paired with the numbers 13 through 23, respectively. This modification allows the clock to also be read in 24-hour notation. This kind of 12-hour clock can be found in countries where the 24-hour clock is preferred.


12-hour clock, History and use, Use by country
In several countries the 12-hour clock is the dominant written and spoken system of time, predominantly in nations that were part of the former British Empire, for example, the United Kingdom, Republic of Ireland, the United States, Canada (excluding Quebec), Australia, New Zealand, India, Pakistan, Bangladesh, Malaysia, and Malta, and others follow this convention as well, such as Egypt, Mexico, Nepal and the former American colony of the Philippines. In most countries, however, the 24-hour clock is the standard system used, especially in writing. Some nations in Europe and Latin America use a combination of the two, preferring the 12-hour system in colloquial speech but using the 24-hour system in written form and in formal contexts.


12-hour clock, History and use, Use by country
The 12-hour clock in speech often uses phrases such as  ... in the morning, ... in the afternoon, ... in the evening, and ...at night. Rider's British Merlin almanac for 1795 and a similar almanac for 1773 published in London used them. Other than English-speaking countries, the terms a.m. and p.m. are seldom used and often unknown.


12-hour clock, History and use, Computer support
In most countries, computers by default show the time in 24-hour notation. Most operating systems, including Microsoft Windows and Unix-like systems such as Linux and macOS, activate the 12-hour notation by default for a limited number of language and region settings. This behaviour can be changed by the user, such as with the Windows operating system's "Region and Language" settings.


12-hour clock, Abbreviations
The Latin abbreviations a.m. and p.m. (often written "am" and "pm", "AM" and "PM", or "A.M." and "P.M.") are used in English and Spanish. The equivalents in Greek are π.μ. and μ.μ., respectively, and in Sinhala පෙ.ව. (pe.va.) for පෙරවරු (peravaru, පෙර pera – fore, pre) and ප.ව. (pa.va.) for පස්වරු (pasvaru, පස්සේ passē – after, post). However, noon is rarely abbreviated in any of these languages, noon normally being written in full. In Portuguese, there are two official options and many others used, for example, using 21:45, 21h45 or 21h45min (official ones) or 21:45 or 9:45 p.m. In Irish, a.m. and i.n. are used, standing for ar maidin ("in the morning") and iarnóin ("afternoon") respectively.


12-hour clock, Abbreviations
Most other languages lack formal abbreviations for "before noon" and "after noon", and their users use the 12-hour clock only orally and informally. However, in many languages, such as Russian and Hebrew, informal designations are used, such as "9 in the morning" or "3 in the night".


12-hour clock, Abbreviations
When abbreviations and phrases are omitted, one may rely on sentence context and societal norms to reduce ambiguity. For example, if one commutes to work at "9:00", 9:00 a.m. may be implied, but if a social dance is scheduled to begin at "9:00", it may begin at 9:00 p.m.


12-hour clock, Related conventions, Typography
The terms "a.m." and "p.m." are abbreviations of the Latin ante meridiem (before midday) and post meridiem (after midday). Depending on the style guide referenced, the abbreviations "a.m." and "p.m." are variously written in small capitals ("am" and "pm"), uppercase letters without a period ("AM" and "PM"), uppercase letters with periods, or lowercase letters ("am" and "pm" or, more commonly, "a.m." and "p.m."). With the advent of computer generated and printed schedules, especially airlines, the "M" character is often omitted as providing no additional information as in "9:30A" or "10:00P".


12-hour clock, Related conventions, Typography
Some style guides suggest the use of a space between the number and the a.m. or p.m. abbreviation. Style guides recommend not using a.m. and p.m. without a time preceding it, although doing so can be advantageous when describing an event that always happens before or after noon.


12-hour clock, Related conventions, Typography
The hour/minute separator varies between countries: some use a colon, others use a period (full stop), and still others use the letter h. In many instances using the 24-hour clock, there is no separator between hours and minutes (0800, read as written, i.e. "zero-eight-hundred" or more commonly substituting the letter O for the numeral zero, as "oh-eight-hundred").


12-hour clock, Related conventions, Typography, Encoding
They are meant to be used only with Chinese-Japanese-Korean character sets, as they take up exactly the same space as one CJK character.


12-hour clock, Related conventions, Informal speech and rounding off
In speaking, it is common to round the time to the nearest five minutes and/or express the time as the past (or to) the closest hour; for example, "five past five" (5:05). Minutes past the hour means those minutes are added to the hour; "ten past five" means 5:10. Minutes to, 'til and of the hour mean those minutes are subtracted; "ten of five", "ten 'til five", and "ten to five" all mean 4:50.


12-hour clock, Related conventions, Informal speech and rounding off
Fifteen minutes is often called a quarter hour, and thirty minutes is often known as a half hour. For example, 5:15 can be phrased "(a) quarter past five" or "five-fifteen"; 5:30 can be "half past five", "five-thirty" or simply "half five". The time 8:45 may be spoken as "eight forty-five" or "(a) quarter to nine".


12-hour clock, Related conventions, Informal speech and rounding off
In older English, it was common for the number 25 to be expressed as "five-and-twenty". In this way the time 8:35 may be phrased as "five-and-twenty to 9", although this styling fell out of fashion in the later part of the 1900s and is now rarely used.


12-hour clock, Related conventions, Informal speech and rounding off
Instead of meaning 5:30, the "half five" expression is sometimes used to mean 4:30, or "half-way to five", especially for regions such as the American Midwest and other areas that have been particularly influenced by German culture. This meaning follows the pattern choices of many Germanic and Slavic languages, including Serbo-Croatian, Dutch, Danish, Russian and Swedish, as well as Hungarian and Finnish.


12-hour clock, Related conventions, Informal speech and rounding off
Moreover, in situations where the relevant hour is obvious or has been recently mentioned, a speaker might omit the hour and just say "quarter to (the hour)", "half past" or "ten 'til" to avoid an elaborate sentence in informal conversations. These forms are often commonly used in television and radio broadcasts that cover multiple time zones at one-hour intervals.


12-hour clock, Related conventions, Informal speech and rounding off
In describing a vague time of day, a speaker might say the phrase "seven-thirty, eight" to mean sometime around 7:30 or 8:00. Such phrasing can be misinterpreted for a specific time of day (here 7:38), especially by a listener not expecting an estimation. The phrase "about seven-thirty or eight" clarifies this.


12-hour clock, Related conventions, Informal speech and rounding off
Some more ambiguous phrasing might be avoided. Within five minutes of the hour, the phrase "five of seven" (6:55) can be heard "five-oh-seven" (5:07). "Five to seven" or even "six fifty-five" clarifies this.


12-hour clock, Related conventions, Formal speech and times to the minute
Minutes may be expressed as an exact number of minutes past the hour specifying the time of day (e.g., 6:32 p.m. is "six thirty-two"). Additionally, when expressing the time using the "past (after)" or "to (before)" formula, it is conventional to choose the number of minutes below 30 (e.g., 6:32 p.m. is conventionally "twenty-eight minutes to seven" rather than "thirty-two minutes past six").


12-hour clock, Related conventions, Formal speech and times to the minute
In spoken English, full hours are often represented by the numbered hour followed by o'clock (10:00 as ten o'clock, 2:00 as two o'clock). This may be followed by the "a.m." or "p.m." designator, though some phrases such as in the morning, in the afternoon, in the evening, or at night more commonly follow analog-style terms such as o'clock, half past three, and quarter to four.


12-hour clock, Related conventions, Formal speech and times to the minute
O'clock itself may be omitted, telling a time as four a.m. or four p.m. Minutes ":01" to ":09" are usually pronounced as oh one to oh nine (nought or zero can also be used instead of oh). Minutes ":10" to ":59" are pronounced as their usual number-words. For instance, 6:02 a.m. can be pronounced six oh two a.m. whereas 6:32 a.m. could be told as six thirty-two a.m.


12-hour clock, Confusion at noon and midnight
It is not always clear what times "12:00 a.m." and "12:00 p.m." denote. From the Latin words meridies (midday), ante (before) and post (after), the term ante meridiem (a.m.) means before midday and post meridiem (p.m.) means after midday. Since "noon" (midday, meridies (m.)) is neither before nor after itself, the terms a.m. and p.m. do not apply. Although "12 m." was suggested as a way to indicate noon, this is seldom done and also does not resolve the question of how to indicate midnight.


12-hour clock, Confusion at noon and midnight
The American Heritage Dictionary of the English Language states "By convention, 12 AM denotes midnight and 12 PM denotes noon. Because of the potential for confusion, it is advisable to use 12 noon and 12 midnight."


12-hour clock, Confusion at noon and midnight
E. G. Richards in his book Mapping Time provided a diagram in which 12 a.m. means noon and 12 p.m. means midnight.


12-hour clock, Confusion at noon and midnight
The style manual of the United States Government Printing Office used 12 a.m. for noon and 12 p.m. for midnight until its 2008 edition, when it reversed these designations and then retained that change in its 2016 revision.


12-hour clock, Confusion at noon and midnight
Many U.S. style guides, and NIST's "Frequently asked questions (FAQ)" web page, recommend that it is clearest if one refers to "noon" or "12:00 noon" and "midnight" or "12:00 midnight" (rather than to "12:00 p.m." and "12:00 a.m."). The NIST website states that "12 a.m. and 12 p.m. are ambiguous and should not be used."


12-hour clock, Confusion at noon and midnight
The Associated Press Stylebook specifies that midnight "is part of the day that is ending, not the one that is beginning."


12-hour clock, Confusion at noon and midnight
The Canadian Press Stylebook says, "write noon or midnight, not 12 noon or 12 midnight." Phrases such as "12 a.m." and "12 p.m." are not mentioned at all. Britain's National Physical Laboratory "FAQ-Time" web page states "In cases  where the context cannot be relied upon to place a particular event, the pair of days straddling midnight can be quoted"; also "the terms 12 a.m. and 12 p.m. should be avoided."


12-hour clock, Confusion at noon and midnight
Likewise, some U.S. style guides recommend either clarifying "midnight" with other context clues, such as specifying the two dates between which it falls, or not referring to the term at all. For an example of the latter method, "midnight" is replaced with "11:59 p.m." for the end of a day or "12:01 a.m." for the start of a day. That has become common in the United States in legal contracts and for airplane, bus, or train schedules, though some schedules use other conventions. Occasionally, when trains run at regular intervals, the pattern may be broken at midnight by displacing the midnight departure one or more minutes, such as to 11:59 p.m. or 12:01 a.m.


12-hour run
A 12-hour run is a form of ultramarathon in which each competitor tries to run as far as possible in 12 hours. The event is typically held on 1 to 2 mi (1.6 to 3.2 km) loops, but sometimes is held on 400-metre (0.25 mi) tracks. Some races are held on trails and others are held on sidewalks in city parks. Top runners will often run 60 miles (97 km) or more (the best doing about 100 miles (160 km)), depending on conditions. Some participants will have a crew to help them, while others set up a camp with their equipment and supplies near the starting area, with good access from each loop.


12-hydroxydihydrochelirubine 12-O-methyltransferase
In enzymology, a 12-hydroxydihydrochelirubine 12-O-methyltransferase (EC ) is an enzyme that catalyzes the chemical reaction


12-hydroxydihydrochelirubine 12-O-methyltransferase
Thus, the two substrates of this enzyme are S-adenosyl methionine and 12-hydroxydihydrochelirubine, whereas its two products are S-adenosylhomocysteine and dihydromacarpine.


12-hydroxydihydrochelirubine 12-O-methyltransferase
This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. The systematic name of this enzyme class is S-adenosyl-L-methionine:12-hydroxydihydrochelirubine 12-O-methyltransferase. This enzyme participates in alkaloid biosynthesis i.


12-inch coast defense mortar
The 12-inch coast defense mortar was a weapon of 12-inch (305 mm) caliber emplaced during the 1890s and early 20th century to defend US harbors from seaborne attack. In 1886, when the Endicott Board set forth its initial plan for upgrading the coast defenses of the United States, it relied primarily on mortars, not guns, to defend American harbors. Over the years, provision was made for fortifications that would mount some 476 of these weapons, although not all of these tubes were installed.


12-inch coast defense mortar
Ninety-one of these weapons were remounted as railway artillery in 1918-1919, but this was too late to see action in World War I. The railway mortars were only deployed in small quantities, and none overseas. The fixed mortars in the Philippines saw action in the Japanese invasion in World War II. All of the fixed mortars (except four) in the United States were scrapped by 1944, as new weapons replaced them, and the railway mortars were scrapped after the war.


12-inch coast defense mortar
Today, the only remaining mortars of this type in the 50 states are four at Battery Laidley, part of Fort Desoto near St. Petersburg, Florida, but the remains of coast defense mortar emplacements can be seen at many former Coast Artillery forts across the United States and its former territories. Additional 12-inch mortars and other large-caliber weapons remain in the Philippines.


12-inch coast defense mortar, The weapons
The M1890M1 (Model of 1890, Modification 1) 12-inch mortar was one of the most powerful coast artillery pieces of its era, and was the most common type emplaced to guard U.S. harbors.


12-inch coast defense mortar, The weapons
This mortar and other models, the M1886, M1908, and M1912, usually fired deck-piercing (also called armor-piercing) shells. These weighed from 700 to 1,046 pounds (318 to 474 kg) and had heavy, hardened steel caps, designed to pierce a ship's deck armor before the shell exploded. These mortars, firing the half-ton shells at an elevation of 45 degrees, had a range of 12,019 yards (10,990 m) (about 7 miles).


12-inch coast defense mortar, The weapons
The deck-piercing shells were usually the ammunition of choice, because even the heaviest battleships of the 1890-1920 period were relatively lightly armored on the tops of their main decks, so a plunging half-ton shell could inflict crippling damage on one of them. Early on (from about 1890 to 1915), coast defense mortars were also supplied with so-called "torpedo shells" weighing 800 or 1,000 pounds (360 or 450 kg) (see illustration at right, below). These were thin-walled shells roughly 5 feet (1.5 m) in length that carried explosive charges of about 130 pounds (59 kg) and were meant to detonate upon contact with the deck of a ship, scattering fragments among the crew.


12-inch coast defense mortar, The weapons
The M1890M1 mortar was most often installed on an M1896 carriage. The mortar and its carriage weighed a total of 78.5 tons. The carriage was geared to enable it to be turned (in azimuth) by means of a traversing crank with two handles, located on the right side of the piece. A ring marked in degrees of azimuth ran around the mortar, just outside the inner steel circle or "racer" that carried the carriage, and a soldier read a pointer on the racer to aim the mortar in direction.


12-inch coast defense mortar, The weapons
The tube was raised or lowered (in elevation) by twin geared wheels with long spokes (resembling ship's wheels) that were located on either side of the carriage. The breech could be rapidly depressed to an almost level position for loading and then be quickly elevated for firing. Other carriages included the M1891 and M1908.


12-inch coast defense mortar, The weapons
In addition to the elevation of its tube, the factor that determined the mortar's range was the size of the powder charge that was loaded into its breech, following the shell. The desired range for the mortar was specified in terms of zones. The smallest zone (shortest range) was Zone 1, and the largest (longest range) was Zone 9.


12-inch coast defense mortar, The weapons
With the so-called "aliquot charge" (shown in the photo at right), up to 9 equal-sized, disk-shaped bags of powder (each about 2 inches (51 mm) thick and containing 6.3 pounds (2.9 kg) of powder) could be attached to a 10th (or "base") bag, by means of cloth binding straps that were sewn to the base bag. Often the base bag was painted red, indicating that the powder assembly was to be loaded into the breech "red end last," so that it bumped up against the closing breech block (or faced the gunner). The red base bag also contained a small charge of black powder as an igniter. When the breech was closed, a detonator was inserted through the breech block and contacted the igniter, ready to set off the full powder charge.


12-inch coast defense mortar, The weapons
The mortar could be fired in one of two ways: either electrically or manually (by the pull of a lanyard). And each method had its own type of detonator (electrical or friction). Electrical firing required first that the crew attach a wire to the electrical detonator, which protruded from the breech block. Second, the crew had to connect the firing cable coming out of the pit floor to the carriage of the individual mortar, out in the pit.


12-inch coast defense mortar, The weapons
Third, the circuit switch (usually located on the wall of the pit near the data booth) leading to the individual mortar had to be thrown into the closed (firing) position. Finally, the firing magneto, which was mounted on a special "shoe", often on the wall of the pit near the data booth, had to be cranked up and then released, sending the firing current out to the pit. Depending on the switch settings, the mortars in a given pit could be fired one at a time or all together. Lanyard firing had fewer fail-safe features, and was accomplished by a crewman who stood well behind the breech and pulled smartly on the lanyard to fire the individual mortar.


12-inch coast defense mortar, Emplacement design history
The earliest coast defense mortar batteries of the modern era were designed as so-called "Abbot Quads". Named for Gen. Henry Larcom Abbot, the Army engineer who invented the design, Abbot Quads were rectangular configurations of four rectangular mortar pits with four mortars per pit. Often these early pits had rounded corners and one open side which backed up to a magazine corridor or an open concrete pad, while the front side of the pit was protected by a high earthen bank or berm, making the pit invisible to attackers and almost impossible to hit from the sea. A plan for an Abbot Quad mortar battery is shown at left. The earthen prototype for these was built in the 1870s at Fort Totten in New York City, and construction of the first operational Abbot Quads commenced circa 1892.


12-inch coast defense mortar, Emplacement design history
The idea behind the Abbot Quad was to have all 16 mortars in the four pits fire at once, producing a shotgun-like salvo of plunging shells optimally dispersed to destroy an enemy ship. It was argued that targeting each mortar individually would not produce many more hits than salvo firing, since early fire control procedures and equipment were often error-prone. Furthermore, proponents of salvo firing pointed out that it made for easier command and control (particularly under battle conditions), since all mortars in all pits of a battery could be given the same firing data.


12-inch coast defense mortar, Emplacement design history
Early battery designs often contained one central "firing room" from which cables ran out to the various mortar pits, enabling electrical firing of all weapons simultaneously. It is not clear, however, if this method of simultaneous firing for multiple pits (or even for four mortars in one pit) was ever put into practice.


12-inch coast defense mortar, Emplacement design history
However, the early Abbot Quad designs featured very small mortar pits. Often, four mortars were mounted in a pit that was only about 40 by 50 feet (12 by 15 m) in size. Four circular areas about 18 feet (5.5 m) in diameter would fit into one of these early pits, producing a very crowded situation (given that two adjacent M1890 mortars mounted in such a pit would have their muzzles almost touching if they were traversed to face each other). A photo of such an early "crowded pit" is shown at left.


12-inch coast defense mortar, Emplacement design history
When a mortar battery was fully manned, formal guidelines called for a pit containing just two mortars (see photo at right) to be manned by a pit commander, two mortar squads of 17 enlisted men each, and an ammunition squad of 16 enlisted men. One of the last (1942) versions of the manual for the 12-inch mortar gives details on how it was to be crewed and fired.


12-inch coast defense mortar, Emplacement design history
After about 1905, reliance on the Abbot Quad design declined. Some artillery officers argued that salvo firing was inherently wasteful, and that a much better hit ratio could be achieved by aiming each mortar individually against a specified target. They also argued that the smaller, cramped mortar pits of the early Abbot Quad battery designs were simply too crowded for efficient operations, with mortar crews for different tubes constantly getting in each other's way.


12-inch coast defense mortar, Emplacement design history
As fire control methods improved and the network of base end stations for the Coast Artillery fire control system was extended, from about 1905 on, individual aiming of mortars could be more accurate. At the same time, designs for new pits often specified only two mortars per pit, and newer forts had side-by-side, open-back mortar pits. Experience showed the time to reload four tightly-packed mortars in a pit was more than twice the time to reload two mortars in a pit. As a result, many 4-mortar pits were "depopulated," and some of their tubes were sent away to equip newer batteries.


12-inch coast defense mortar, Firing the mortars
that dates from around 1915 shows a firing drill on the 12-inch mortars of Battery Howe, part of the Harbor Defenses of San Francisco. Although the battery shown is a linear one, the firing drill is similar to what would have taken place in a square or rectangular pit at Fort Banks. The film clip illustrates how congested one of the old-style pits would have become if used to fire four mortars simultaneously or nearly so.


12-inch coast defense mortar, Firing the mortars
The film shows the heavy shells (on shell carts) being wheeled up to the breeches of the mortars and rammed home, the powder bags being tossed into the breeches after them, the crew clearing the immediate area while the chief of the breech raises his arm to indicate "ready to fire," and the mortars being fired electrically (from outside the area pictured). The tubes are then depressed, crewmen rush back in to swab out the tubes and the process repeats.


12-inch coast defense mortar, Firing the mortars
The shock wave from firing just one of these huge mortars, particularly if it was fired within one of the smaller, old-style pits, was often so strong that it destroyed sensitive equipment mounted near the pit, knocked doors off nearby magazines and barracks, and broke windows in nearby neighborhoods. The thundering crash of four of these mortars being fired simultaneously in a pit must have been overwhelming.


12-inch coast defense mortar, Fire control
The images here show another feature of the mortar pits—the data booth, part of the Coast Artillery fire control system. Personnel in this small space, with its tapered viewing slits, received the coordinates (azimuth and elevation) that had been calculated via plotting board by the battery's Range Unit as the firing coordinates for the mortars in order for them to hit their targets.


12-inch coast defense mortar, Fire control
These booths were either small, free-standing structures, about 10 feet (3.0 m) square and 7 feet (2.1 m) tall (as shown here in the topmost photos), or were built into one of the walls of the mortar pit itself (lower photo at right). The reconstructed data board in the photo at left hangs off the side of the data booth and is used to post the firing coordinates for mortars #3 and #4 in its pit (evidently the only two mortars there).


12-inch coast defense mortar, Fire control
The "Zone" number posted on the board refers to the size of the powder charge to be loaded for the coming shot. The top photo at right shows a decomposed set of slats (which likely used to have slates attached to them) that could have firing data chalked onto them and then be slid out of the data booth so they could be seen by the mortar crews in the pit.


12-inch coast defense mortar, Fire control
Since crews of the mortars could not see their targets, they were especially dependent on the overall fire control system, with its base end stations and plotting room, to locate and pinpoint targets for them to hit.


12-inch coast defense mortar, Railway mortars
After the American entry into World War I on 6 April 1917, the US Army considered converting coast artillery weapons to railway mounts for use on the Western Front. Railway guns were in use by all the major belligerents in the war by that time. Among the weapons that could be spared from fixed defenses were 150 12-inch mortars, removed from 4-mortar pits. Contracts were let for mounting 91 mortars on railway carriages known as the M1918 Carriage (Railway). A hydro-pneumatic recuperator and outriggers allowed for all-around fire from the railway mounting, which weighed 88 tons.


12-inch coast defense mortar, Railway mortars
Forty-five railway mortar carriages were completed by the Morgan Engineering Company of Alliance, Ohio by 7 April 1919. All 91 contracted mortars were eventually mounted; one source states that all of these were the M1890. The following footnoted article shows the firing of an M1890 mortar on a railway mounting. Since the mounting permitted all-around fire and thus tracking of a moving target, the 12-inch railway mortar (along with 8-inch guns and twelve 7-inch guns on similar carriages) was retained after World War I for future coast defense use. The Army conducted tests with railway mortars in the 1930s.


12-inch coast defense mortar, Railway mortars
Some (probably four) of the railway mortars were assigned to Battery C, 52nd Railway Artillery Battalion, and tested at the Sandy Hook Proving Ground at Fort Hancock, New Jersey and also at Fort Miles, Delaware. During World War II, a battery of four railway mortars was among the temporary harbor defenses of Grays Harbor, Washington, and emplacements for an additional battery at Cape George, Washington were constructed but never armed.


12-inch coast defense mortar, Combat service
Probably the only US 12-inch mortars to see action were those in the Philippines in 1942, particularly Battery Way and Battery Geary at Fort Mills on Corregidor. These batteries totaled twelve mortars and were used in the fight against the Japanese invasion. However, as with other US pre-1940 fortifications (most of which were designed well before the airplane was invented), the open-top emplacement design left the mortars open to air and high-angle artillery attack.


12-inch coast defense mortar, Combat service
All but two of the batteries' mortars were knocked out by the latter, all but one of Battery Geary's by a single hit that penetrated the magazine. The mortar batteries had mostly armor-piercing ammunition which would penetrate into the ground before exploding, and therefore was less effective than high explosive ammunition against ground forces.


12-inch coast defense mortar, Combat service
Other 12-inch mortars were Battery Koehler on Carabao Island (Fort Frank), which was used for ineffectual counter-battery fire against the Japanese Kondo Detachment artillery on the southern shore of Manila Bay, and Battery Craighill on Caballo Island (Fort Hughes), which fired at targets generated locally and from Corregidor. Battery Craighill was manned by naval personnel from the gunboat Mindanao. All forts were surrendered on 6 May 1942 along with Corregidor. Ten mortars remain at Batteries Way and Geary while four mortars remain at Fort Hughes as of 2014.


12-inch coast defense mortar, Combat service
In the desperate defense of Corregidor an attempt was made to use these mortars as antiaircraft weapons. Three types of fuzes were tried: powder train and mechanical time fuzes for 3-inch AA guns, and a shrapnel fuze for 155 mm GPF field guns. None of these resulted in detonation of the mortar shell. The leading theories were that either the low rotational velocity of the shell or the small booster charge in the fuzes precluded detonation.


12-inch coast defense mortar, Surviving examples
Nineteen 12-inch mortars survive, mostly in the Philippines, with four at Fort DeSoto on Mullet Key near St. Petersburg, Florida.


12-inch gun M1895
The 12-inch coastal defense gun M1895 (305 mm) and its variants the M1888 and M1900 were large coastal artillery pieces installed to defend major American seaports between 1895 and 1945. For most of their history they were operated by the United States Army Coast Artillery Corps. Most were installed on disappearing carriages, with early installations on low-angle barbette mountings. From 1919, 19 long-range two-gun batteries were built using the M1895 on an M1917 long-range barbette carriage. Almost all of the weapons not in the Philippines were scrapped during and after World War II.


12-inch gun M1895, History
In 1885, William C. Endicott, President Grover Cleveland's secretary of war, was tasked with creating the Board of Fortifications to review seacoast defenses. The findings of the board illustrated a grim picture of existing defenses, and in its 1886 report recommended a massive $127 million construction program of breech-loading cannons, mortars, floating batteries, and submarine mines for some 29 locations on the US coastline. Most of the board's recommendations were implemented. Coast artillery fortifications built between 1885 and 1905 are often referred to as "Endicott Period" fortifications.


12-inch gun M1895, History
Watervliet Arsenal designed the gun and built the barrels. For several years, difficulties were encountered in building a disappearing carriage for the 12-inch gun. One alternative was the M1891 gun lift carriage, with the gun mounted on a large steam-powered elevator. Only one battery of this type was built, Battery Potter at Fort Hancock, New Jersey. When this proved to be too complex, guns were mounted on low-angle M1892 or M1897 barbette carriages. The M1897 carriage was actually an "altered gun lift" carriage, functionally equivalent to the barbette carriage.


12-inch gun M1895, History
Eventually, the guns were mounted on M1896, M1897, or M1901 disappearing carriages designed by Bethlehem Steel; when the gun was fired, it dropped behind a concrete or earthen wall for protection from counter-battery fire. Bethlehem later built barrels as well. Detailed descriptions of the M1888 weapon, disappearing carriage, and gun lift carriage are in the US Army's . Detailed parts lists for the M1888 weapon and supporting equipment are in the .


12-inch gun M1895, History
After the Spanish–American War, the government wanted to protect American seaports in the event of war, and also protect newly gained territory, such as the Philippines and Cuba, from enemy attack. A new Board of Fortifications, under President Theodore Roosevelt's secretary of war, William Taft, was convened in 1905. Taft recommended technical changes, such as more searchlights, electrification, and, in some cases, less guns in particular fortifications. The seacoast forts were funded under the Spooner Act of 1902 and construction began within a few years and lasted into the 1920s. The defenses of the Philippines on islands in Manila Bay were built under this program.


12-inch gun M1895, History, Railway mounting
After the American entry into World War I, the army recognized the need for large-caliber railway guns for use on the Western Front. Among the weapons available were 45 12-inch guns, to be removed from fixed defenses or taken from spares. Twelve M1895 weapons were mounted on M1918 railway carriages (based on the French Batignolles mount) by mid-1919; it is unclear if any more were eventually mounted. A detailed description of the railway mounting is given in Railway Artillery, Vol. I by Lt. Col. H. W. Miller.


12-inch gun M1895, History, Railway mounting
The range of the railway weapon was 25,000 yards (23,000 m) at 38° elevation. Like almost all US-made railway guns of World War I (the notable exception being the US Navy's 14"/50 caliber railway guns), these never left the US. Although the twelve guns survived until early in World War II, they were not deployed. In 1941 they were declared "limited standard", and all but one were scrapped during the war. The survivor was used for experimental purposes at the Naval Surface Warfare Center Dahlgren Division until it was transferred to the U.S. Army Ordnance Training and Heritage Center at Fort Lee, Virginia in the 2000s.


12-inch gun M1895, History, Long-range mounting
Also during World War I, it was recognized that naval guns were rapidly improving and longer-range weapons were needed. Fourteen two-gun and two one-gun batteries were constructed with M1895 guns on the new M1917 long-range barbette carriage, which allowed an elevation of 35 degrees, compared to 15 degrees for the disappearing carriages. This increased the range from 18,400 yards (16,800 m) to 30,100 yards (27,500 m). Eleven of these batteries were in the continental United States, with two in Panama, one in Hawaii, and two one-gun batteries at Fort Mills on Corregidor in the Philippines.


12-inch gun M1895, History, Long-range mounting
The guns were originally in open mounts with protected magazines, but most were casemated against air attack, beginning in 1940 as World War II approached the United States. However, the batteries in the Philippines were not casemated, as the 1923 Washington Naval Treaty prohibited further fortification of US and Japanese Pacific-area possessions, and in 1940–41 there was a lack of resources to do so. In some cases, an M1916 75 mm gun was mounted atop a 12-inch gun for subcaliber training.


12-inch gun M1895, History, World War II
Along with other coast artillery weapons, the 12-inch guns in the Philippines saw action in the Japanese invasion in World War II. Since they were positioned against a naval attack, they were poorly sited to engage the Japanese (although the long-range batteries had 360° fire due to lack of casemates, the disappearing batteries had about 170° fire). Other limiting factors were that they had mostly armor-piercing ammunition, and the open mountings were vulnerable to air and high-angle artillery attack.


12-inch gun M1895, History, World War II
Three additional long-range casemated batteries were constructed during the war, at Fort Miles, Delaware, San Juan, Puerto Rico, and on Sullivan's Island near Fort Moultrie in the Harbor Defenses of Charleston, South Carolina. With the additional construction of 16-inch gun batteries at most harbor defenses, all guns on disappearing carriages were scrapped in 1943–44. The long-range batteries' guns were scrapped soon after the war ended.


12-inch gun M1895, M1895 12-inch coastal artillery batteries
Additional batteries, including 14 two-gun batteries with long-range M1917 carriages (in addition to Batteries Smith and Hearn on Corregidor), were located in the United States and its possessions.


12-inch gun M1895, Specifications, Variations
The M1895MI weighed 52 tons and the M1901 carriage weighed 251 tons. The projectile weight for all M1895 guns was 1,046 pounds. Each shell used 318 pounds of powder, but this was varied depending on range. The projectile achieved a muzzle velocity of 2,250 feet per second. The M1901 disappearing carriage could elevate 15 degrees maximum; earlier models could not elevate that much until the rear mounting bracket was changed from a centerline to an upper position in the M1901. The M1901 could traverse 170 degrees, but some M1895MII emplacements could traverse 210 degrees. The M1895MII had a range of over 29,000 yards (26 kilometers).


12-inch/35-caliber gun
The 12"/35 caliber gun (spoken "twelve-inch-thirty-five–caliber") were used for the primary batteries of the United States Navy's "New Navy" monitors Puritan and  Monterey and the battleships Texas and Iowa.


12-inch/35-caliber gun, Mark 1
The Navy's Policy Board call for a variety of large caliber weapons in 1890, with ranges all the way up to 16-inch (406 mm), led to the development of the 12-inch (305 mm)/35 caliber gun. The Mark 1, gun Nos. 1–8, was constructed of gun steel, having a tube, jacket, ten hoops and a locking ring. The Mod 0, the original design, had the inner hoop starting 6 in (150 mm) from the breech and running out to the muzzle, with the Mod 1 being hooped from breech to muzzle.


12-inch/35-caliber gun, Mark 2
The Mark 2, gun Nos. 9–14 and 57, was of similar construction to the Mark 1 but with seven hoops starting from the breech and running out to the muzzle. The Mark 2 Mod 1 and Mod 2 were also given a new nickel-steel liner.


12-inch/35-caliber gun, Incident
Gun No. 9, mounted in Iowa's forward turret in the left-hand position, was damaged on 9 April 1903, off Pensacola, Florida, when the chase, forward of the "D" hoop, was blown off during target practice. The gun had been assembled in 1895 at the US Naval Gun Factory. The gun had fired 127 rounds with the accident happening on the 128th round. No one inside the turret were injured, but fragments of the chase were driven through the deck under the muzzle killing three men on the deck below; four others were slightly wounded. The gun was removed and sent back to the Naval Gun Factory to be examined by a special board. Their theory was that a pressure wave had built up from the burning of older smokeless powder used.


12-inch/40-caliber gun
The 12"/40 caliber gun (spoken as "twelve-inch-forty--caliber") were used for the primary batteries of the United States Navy's last class of monitors and the  Maine-class and  Virginia-class pre-dreadnought battleships.


12-inch/40-caliber gun, Design
The 12-inch (305 mm)/40 caliber gun was developed after the Spanish–American War to use the new smokeless powder that had recently been adopted by the Navy. The Mark 3, gun Nos. 15–48 and 50–56, was constructed of tube, jacket, and eight hoops. It was found that the early guns suffered from excessive bore erosion, in an attempt to fix this the Navy reduced the propellant charges to reduce the muzzle velocity, because of this the Mark 4, gun Nos. 49, 58–60, 150–154, and 179, was similar to the Mark 3 but with a smaller chamber for the reduced propellant charge.


12-inch/40-caliber gun, Service history
The guns mounted in the Virginia-class battleships were in an unusual two-level turret with the 8-inch (203 mm)/45 caliber guns on top of the larger 12-inch guns. This arrangement ultimately proved unsuccessful but helped the Navy in the successful development of superfiring turrets later used in the dreadnought South Carolina.


12-inch/40-caliber gun, Incident
Gun No. 49, while testing powder at the Naval Proving Ground, had the entire muzzle and chase blow off. The board appointed to investigate came to the conclusion that the new powder, while performing properly, caused a pressure along the chase that was dangerously close to the strength curve. It was decided that when the guns were withdrawn to be relined they would add an additional hoop that extended to the muzzle would be places on the chase.


12-inch/45-caliber Mark 5 gun
The 12″/45 caliber Mark 5 gun was an American naval gun that first entered service in 1906. Initially designed for use with the Connecticut-class of pre-dreadnought battleships, the Mark 5 continued in service aboard the first generation of American dreadnoughts.


12-inch/45-caliber Mark 5 gun, Design and development
The 12-inch (305 mm)/45 caliber Mark 5 naval gun was designed as an incremental improvement upon the preceding American naval gun, the 12"/40 caliber gun Mark 4. As such, it was a very similar weapon, having been lengthened by 5 calibers to allow for improved muzzle velocity, range, and penetrating power. Designed to the specifications of the Bureau of Ordnance, the Mark 5 was constructed at the U.S. Naval Gun Factory in Washington, D.C.


12-inch/45-caliber Mark 5 gun, Measurements and Capabilities
The Mark 5 weighed 53 short tons (48 t) and was capable of firing 2 to 3 times a minute. At maximum elevation of 15° it could fire an 870 lb (390 kg) shell approximately 20,000 yd (18,000 m). However, this range was largely academic at the time the gun was initially designed, as no rangefinding techniques had yet been developed capable of accurately firing beyond about 10,000 yd (9,100 m). With an initial muzzle velocity of 2,700 ft/s (820 m/s), the gun had a barrel life of 175 rounds, and was capable of firing either Armor Piercing or Common projectiles.


12-inch/45-caliber Mark 5 gun, Measurements and Capabilities
As designed, the Mark 5 was capable of penetrating 16.6 in (420 mm) of Harvey plated side armor at 6,000 yd (5,500 m), 12.2 in (310 mm) at 9,000 yd (8,200 m), and 9.9 in (250 mm) at 12,000 yd (11,000 m). By comparison the 12-inch/40 caliber Mark 4 it replaced could only penetrate 14.6 in (370 mm), 11.6 in (290 mm), and 9.4 in (240 mm) at those distances, respectively.


12-inch/45-caliber Mark 5 gun, Naval Service
The Mark 5 entered service in 1906 and remained the primary battleship gun for all American battleships commissioned before 1912, at which point it was replaced by the 12"/50 caliber Mark 7. All told, the Mark 5 would arm 14 battleships of five different classes, making it the most-utilized main gun in American battleship history. Despite this distinction, the only Mark 5 guns ever to be fired in anger were actually in Greek, and not American, service.


12-inch/45-caliber Mark 5 gun, Naval Service
The ex-Mississippi-class battleships Kilkis and Lemnos, sold to the Royal Hellenic Navy in 1914, fought in both the Allied Intervention in the Russian Civil War, and the Greco-Turkish War. Though during World War I the Mark 5 would cross the Atlantic for duty aboard two of the American battleships serving in the 6th Battle Squadron of the Grand Fleet, it was never fired in any engagement, as no battles were fought with the German High Seas Fleet in 1918.


12-inch/45-caliber Mark 5 gun, Naval Service
In American service, the Mark 5 remained afloat (albeit in dwindling numbers) until 1930, when the last guns were removed from the Floridas in compliance with the terms of the London Naval Treaty.


12-inch/45-caliber Mark 5 gun, Naval Service, Survivor
A Mark 5 Mod 8 gun is displayed at Fort Hamilton in Brooklyn, New York, representative of the general type of coast artillery guns the fort had.


12-inch/45-caliber Mark 5 gun, Incident
During the summer of 1916, Michigan blew out her left hand gun in turret No. 2 during target practice. After an investigation of South Carolina's guns it was discovered that copper deposits from the driving bands on the projectiles had narrowed the bores of the barrel enough that it caused the projectiles to slow down. This problem, known as "copper choke", allowed the pressure in the barrel to increase to dangerous levels. Lapping heads, to remove these deposits, were issued for all guns 12-inch and larger throughout the fleet. The lapping heads were later replaced by wire and pisaba brushes.


12-inch/45-caliber Mark 5 gun, Coastal Artillery
Following the signing of the Washington Naval Treaty in 1922, many of the Mark 5 guns in service were removed from sea duty and transferred to the U.S. Army for use as coastal artillery. In this capacity, the maximum range of the Mark 5 increased to 30,000 yd (27,000 m), due to the greater elevation that was possible. These guns were not deployed by the US Army, and some were sold to Brazil, where they might still be in use. In Greek service, the guns removed from Lemnos were emplaced on the island of Aegina, where they helped to defend the approaches to the port of Athens.


12-inch/50-caliber Mark 7 gun
The 12"/50 caliber Mark 7 gun (spoken "twelve-inch-fifty-caliber") was a United States Navy's naval gun that first entered service in 1912. Initially designed for use with the Wyoming-class of dreadnought battleships, the Mark 7 also armed the Argentine Navy's Rivadavia-class battleships.


12-inch/50-caliber Mark 7 gun, Design and development
The 12-inch (305 mm)/50 caliber Mark 7 naval gun was only a slight improvement over the preceding American naval gun, the 12"/45 caliber Mark 5 gun. As such, it was a very similar weapon, having been lengthened by five calibers to allow for improved muzzle velocity, range, and penetrating power. Designed to the specifications of the Bureau of Ordnance, the Mark 7 was constructed at the U.S. Naval Gun Factory in Washington, D.C.


12-inch/50-caliber Mark 7 gun, Design and development
The Mark 7 weighed 124,140 lb (56,310 kg) with the breech and was capable of firing two to three times a minute. At maximum elevation of 15° it could fire an 870 lb (390 kg) shell approximately 20,000 yd (18,000 m). With an initial muzzle velocity of 2,900 ft/s (880 m/s), the gun had a barrel life of 200 rounds, and was capable of firing either armor piercing or Common projectiles.


12-inch/50-caliber Mark 7 gun, Design and development
As designed, the Mark 7 was capable of penetrating 17.4 in (440 mm) of Harvey plated side armor at 6,000 yd (5,500 m), 14.7 in (370 mm) at 9,000 yd (8,200 m), and 12.3 in (310 mm) at 12,000 yd (11,000 m). By comparison the 12"/45 caliber Mark 5 it replaced could penetrate 16.6 in (420 mm), 12.2 in (310 mm), and 9.9 in (250 mm) at those distances, respectively.


12-inch/50-caliber Mark 7 gun, Design and development
Bethlehem Steel built the first gun, No. 180. Mod 0, Nos. 181, 182, and 186–200, was a built-up gun consisted of a tube, jacket, and eight hoops, a screw-box liner with locking hoops and rings and hand operated and Smith-Asbury mechanism. The gun was constructed with nickel-steel and hooped to the muzzle.


12-inch/50-caliber Mark 7 gun, Design and development
Mod 1 was gun No. 180, rebuilt into gun No. 180L, with its chase hoops rebuilt along with a new conical nickel-steel liner, a smaller chamber, and the rifling increased.


12-inch/50-caliber Mark 7 gun, Design and development
Mod 2, gun Nos. 183–185, was a Mod 0 gun relined with a conical liner, a new chase locking hoop, and with a locking ring added. This brought the weight up to 125,498 lb (56,925 kg), with the breech. It also had a 25 cu in (410 cm3)smaller chamber.


12-inch/50-caliber Mark 7 gun, Design and development
The Mod 3 guns, Nos. 211–216, were the last new guns built, all other Mods were Mod 0, 2, or 3 guns that were modified. These guns were built with a new simplified design, no liner, five hoops, a locking ring, along with a screw-box liner and a different gas check seat.


12-inch/50-caliber Mark 7 gun, Design and development
Mod 4, the twelve guns from Wyoming, relined in 1921–1923, had a conical one-step liner and uniform rifling with a new chase locking hoop and locking ring. With the Mod 5 an attempt was made to reline a Mod 1 with a uniform twist rifling, but it was dropped. Mod 6 relined Mod 2 with a uniform twist rifling along with a modified new chase hoop and locking ring. Mod 7 took the Mod 3 and used a one-step conical liner, uniform twist rifling, and added a tube and liner locking ring.


12-inch/50-caliber Mark 7 gun, Design and development
Mod 8 was the Mod 0 or Mod 4 also using a one-step conical liner, uniform twist rifling that was secured by a tube and liner locking ring with a liner locking collar at the breech end. The Mod 8s that used Mod 0 guns also added a new chase hoop and locking ring. Mod 9 was a Mod 2 or Mod 6 that had a new liner with longitudinal clearances at the liner shoulders installed, uniform twist rifling along with a tube and liner locking ring and collar added at the breech end.


12-inch/50-caliber Mark 7 gun, Design and development
Mod 10, like the Mod 9, was also a Mod 2 or Mod 6 that had a new liner with longitudinal clearance at the liner shoulders installed, uniform twist rifling along with a tube and liner locking ring and collar added at the breech end. The Mod 10 used Breech Mechanism Mark 9 instead of the Mark 8 on the previous Mods. Mod 11 was a Mod 7 that had the chamber lengthened, adding 235 cu in (3,851 cm3), and a 3½° breech band seating slope and used Breech Mechanism Mark 12.


12-inch/50-caliber Mark 7 gun, Design and development
Mod 12 used a Mod 10 and lengthened the chamber and added a 3½° breech band seating slope with Mod 13 being similar but of a Mod 8, Mod 14 used a Mod 9, Mod 15 used a Mod 7, Mod 16 used a Mod 10, Mod 17 used a Mod 8, and Mod 18 a Mod 9. Mod 19, the last modification, used a Mod 2 with its breech modified for the Smith-Asbury Breech Mechanism and the forward end of the chamber modified similar to the Mod 18, lengthened the chamber and added a 3½° breech band seating slope. The breech end was further modified by being machined out so that it could accommodate a gas check seat liner locking ring. The Mod 19 could also be used right or left handed by cutting a new slide keyway that was 180° from the original keyway.


12-inch/50-caliber Mark 8 gun
The 12"/50 caliber gun Mark 8 was a US naval gun mounted on the  Alaska-class cruiser. The gun, like the "large cruiser" that mounted it, was intended to fill the gap between US "heavy cruisers" (6-8") and US battleships (14-16"). The name describes the size of the shells, 12 inches in diameter, and the length of the bore in calibers (bore diameters), or 50 feet.


12-inch/50-caliber Mark 8 gun, Design and production
The gun was designed in 1939, and a prototype was tested in 1942. Unlike previous guns, such as the 16"/45 caliber guns used on the  North Carolina class, which were completely made and assembled at the Naval Gun Factory in Washington D.C., the forgings for the Mark 8 were manufactured at the Midvale and Bethlehem Steel corporations. They were then sent to the Naval Gun Factory for processing, which was followed by a trip to Watervliet Arsenal until they were 65% complete. Finally, the built-up guns were sent back to the Naval Gun Factory to be finished.


12-inch/50-caliber Mark 8 gun, Design and production
The gun was first deployed in 1944, on the lead ship of the Alaska class, USS Alaska. The two Alaska-class ships each had nine Mark 8 guns mounted in three triple (3-gun) turrets, with two turrets forward and one aft, a configuration known as "2-A-1". Only two vessels of the class were completed, making them the only applications of the Mark 8 12"/50 caliber gun.


12-inch/50-caliber Mark 8 gun, Measurements
The Mark 8 weighed 121,856 pounds (55,273 kg) including the breech and was capable of an average rate of fire of 2.4–3 rounds a minute. It could throw a 1,140 lb. (517.093 kg) Mark 18 armor-piercing shell 38,573 yards (35,271 meters) at an elevation of 45°.


12-inch/50-caliber Mark 8 gun, Measurements
The previous 12" gun manufactured for the U.S. Navy was the Mark 7 version, used in the World War I era  Wyoming-class battleships, could only throw an 870-pound (390 kg) shell 24,000 yards (21,946 m), at an elevation of 15°  The Mark 8's significant improvement in firing weight and range over the Mark 7 gave it the honor of "by far the most powerful weapon of its caliber ever placed in service." In fact, as a result of the decision to fire "super heavy" armor-piercing projectiles, the Mark 8's deck plate penetration was better and the side belt armor penetration equal to the older (but larger) 14"/50 caliber gun.


12-inch/50-caliber Mark 8 gun, Measurements
The barrel life of the Mark 8 guns was 344 rounds, 54 more than the 16"/50 caliber Mark 7 gun found in the  Iowa-class battleships.


12-oxophytodienoate reductase
12-oxophytodienoate reductase (OPRs) is an enzyme of the family of Old Yellow Enzymes (OYE). OPRs are grouped into two groups: OPRI and OPRII – the second group is the focus of this article, as the function of the first group is unknown, but is the subject of current research. The OPR enzyme utilizes the cofactor flavin mononucleotide (FMN) and catalyzes the following reaction in the jasmonic acid synthesis pathway:


12-oxophytodienoate reductase
This reaction occurs in peroxisomes in plants. Several isozymes have been discovered, with varying substrate stereospecificity: three in Lycopersicon esculentum, 13 in Oryza sativa, and five in Arabidopsis thaliana. The OPR3 isozyme is most extensively studied because it can reduce all 4 stereoisomers of the substrate, OPDA and because it has shown to be the most significant enzyme in the jasmonic acid synthesis pathway.


12-oxophytodienoate reductase, Structure
12-oxophytodienoate reductase structure resembles OYE enzymes and has been elucidated by x-ray crystal structures. The cDNA encodes 372 amino acids for this enzyme. It exhibits a barrel fold of eight parallel beta-strands surrounded by eight alpha-helices to create a barrel shape. Turns at the N-terminus loops of the beta-strands have been shown to contain three to four amino acid residues and the C-terminus loops range between three and 47 amino acid residues. The C-terminus loops largely make up the active site and the larger range of the amount of residues is due to the diversity in the different isozyme active sites.


12-oxophytodienoate reductase, Structure
OPR3, the most extensively studied isoform of 12-oxophytodienoate reductase, has a wider binding pocket than OPR1, which is enantioselective for only one OPDA substrate enantiomer. The residues Tyr78 and Tyr246 that are at the mouth of the active site are responsible for the higher enantioselectivity of OPR1. OPR1 and OPR3 have identical substrate binding residues, but the difference in the width of the mouth of the active site determines the OPR1 specificity.


12-oxophytodienoate reductase, Structure
12-oxophytodienoate reductase has also been shown to practice self-inhibition by dimerization. This is the only flavoprotein known to dimerize for inhibition and this dimerization is thought to be regulated by phosphorylation. The dimerization occurs by the mutual binding of two loops into the two active sites. These loops are highly evolutionarily conserved, indicating the dimerization is purposeful and significant in regulation.


12-oxophytodienoate reductase, Mechanism
The reduction mechanism employed has been shown to be a ping-pong, bi-bi mechanism. The FMN cofactor is first reduced by NADPH, the substrate is then bound, and finally the substrate is reduced by a hydride transfer from NADPH to the substrate’s beta carbon. The Km of OPR3 in Zea mays was found to be 190 micromolar for its substrate OPDA.


12-oxophytodienoate reductase, Biological Function
The reaction catalyzed by 12-oxophytodienoate reductase is in the jasmonic acid biosynthesis pathway. Jasmonic acid is known for its importance as a gene regulator for development and defense.


12-oxophytodienoate reductase, Biological Function
OPR3 is shown to be induced by touch, wind, UV light, application of detergent, wounding, and brassinosteroids. In wound response, its activity has been shown to partially depend on jasmonic acid perception. It is also shown to have greater enzyme efficiency than OPR1 and OPR2 in Arabidopsis thaliana, showing it is the significant enzyme in the jasmonic acid biosynthesis pathway.


12-oxophytodienoate reductase, Relevance to Agriculture
This enzyme is of interest in plant biology research because the disrupted OPR3 gene has been shown to cause male sterility in Arabidopsis thaliana. This is a point of interest in understanding the factors surrounding viable pollen development, a focus of research in the agriculture industry.


12-oxophytodienoate reductase, Relevance to Phytoremediation
OPR has shown to also function in the reduction of explosive 2,4,6-trinitrotoluene (TNT). Because TNT is a known toxic, environmental pollutant that is difficult to degrade, the use of phytoremediation to clean up sites contaminated with TNT is of significant interest. OPR1 degraded TNT faster and with greater amount of degraded products than other isozymes. This enzyme could therefore be used in phytoremediation.


12-oxophytodienoate reductase, Phylogenetics
A phylogenetic analysis studying the structural evolution and functional divergence of the various OPR paralogues found seven conserved sub-families and suggested expansion of the OPR families occurred in land plants. A total of 74 OPR genes in 11 species from six major plant lineages were found. Surprisingly, introns were found to differ in length and number, but conserved in position, indicating successive intron loss. The study also indicated that the substrate binding loop and the alpha-helices, but not the beta-sheets, were critical for functional divergence after sub-families were established and are therefore important in the OPR proteins.


12-pounder Whitworth rifle
The 12-pounder Whitworth rifle was a medium caliber field gun deployed during the mid-19th century. Designed by Joseph Whitworth, the gun was most notably used during the American Civil War. The gun was also used by the Imperial Brazilian Army in the War of the Triple Alliance.


12-pounder Whitworth rifle, Description
The 12-pdr rifle was designed  in the early 1850s by British manufacturer Joseph Whitworth, who had recently been contracted to improve the Pattern 1853 Enfield. During his experiments with the Enfield, Whitworth was inspired to begin experimenting with a hexagonally-rifled barrel; Whitworth would later apply these principles to his field guns.


12-pounder Whitworth rifle, Description
Along with Whitworth's smaller 3-pdr gun, the artillery piece was considered for adoption by the British government's Board of Ordnance. However, Whitworth's guns eventually lost out to the Armstrong gun. During the American Civil War the weapon was exported and saw service in the Union and Confederate armies, though it was considered a rarity.


12-pounder Whitworth rifle, Description
From a design standpoint, the weapon was unique. Like all of Whitworth's designs, the weapon had a distinctive hexagon-ally rifled barrel and was a breechloader (though it could be loaded via the muzzle with modifications). The cannon was forged using a method in which iron plates would be overlapped and forced together using hydraulic presses.


12-pounder Whitworth rifle, Description
The 12-pounder Whitworth saw service with the Army of Northern Virginia. One Whitworth was used in the Confederate defense of Charleston. The weapon saw some service in the Union army (notably with the Army of the Potomac in the Peninsula campaign), and in one instance a group of Americans living in England gifted a battery of four Whitworths to the United States government.


12-pounder Whitworth rifle, Description
Despite being a rarity in the Civil War (one source states the weapon only saw Confederate service with the Army of Northern Virginia), a replica 12-pounder Whitworth was used on the set of The Good, the Bad and the Ugly.


12-pounder gun
12-pounder gun or 12-pdr, usually denotes a gun which fired a projectile of approximately 12 pounds.


12-pounder long gun
The 12-pounder long gun was an intermediary calibre piece of artillery mounted on warships of the Age of sail. They were used as main guns on the most typical frigates of the early 18th century, on the second deck of fourth-rate ships of the line, and on the upper decks or castles of 80-gun and 120-gun ships of the line. Naval 12-pounders were similar to 12-pound Army guns in the Gribeauval system: the canon lourd de 12 Gribeauval, used as a siege weapon, and the canon de 12 Gribeauval, which was considered a heavy field artillery piece.


12-pounder long gun, Usage
As the 12-pounder calibre was consistent with both the French and the British calibre systems, it was a widespread gun amongst nations between the 17th and the 19th century. From the late 18th century, the French Navy used the 12-pounder in three capacities: as main gun on early frigates under Louis XIV, on standard frigates under Louis XV and on light frigates under Louis XVI; as secondary artillery on 64-gun ships; to arm the castles of 80-gun ships of the line; and to equip the third deck of early first-rate ships.


12-pounder long gun, Usage
Under Louis XIV, frigates were organised into "first-rank frigates", which were small two-deckers comparable in role to the 60-gun ships of the 19th century, and smaller "second-rank" frigates. The first-rank frigates carried the 12-pounder as main artillery on their lower deck. Later, under Louis XV, the frigate took its modern shape with a single artillery deck complemented by smaller pieces on the castles; new heavy frigates were developed to carry 26 12-pounders, with Hermione as lead ship of the series. Hermione was captured by the British in 1757 and was swiftly imitated.


12-pounder long gun, Usage
A breakthrough towards fielding heavier guns was made in 1772, when the two units of the  Pourvoyeuse class were built, with 24-pounders intended, but 18-pounders used in practice, and the 12-pounder remained the standard issue on most units. Under Louis XVI, the heavier 18-pounder frigate became predominant, with over 130 units produced, but the French Navy still had around 70 lighter 12-pounder frigates in commission.


12-pounder long gun, Usage
On 64-gun two-deckers, the 12-gun was used as secondary artillery, to supplement the 24-pounder main batteries. 28 guns were carried on the top gun-deck.


12-pounder long gun, Usage
Larger units used the 12-pounder to complement the firepower provided by their main and secondary artillery. On 80-gun ships of the  Tonnant class and  Bucentaure class, they armed the forecastle and the poop deck. On capital ships, the 12-pounder was used on the third deck from the reign of Louis XIV, with units like Royal Louis or Soleil-Royal as typical examples. While the secondary artillery of these 100-gun ships evolved from 18-pounders to 24-pounders, the 12-pounder remained the standard gun on the third deck until 1803, when the  Océan-class ship Impérial became the first 120-gun to carry 18-pounders on her third battery.


12-pounder long gun, Usage
In the Royal Navy, the 12-pounder was used in a similar capacity. The capture of Hermione in 1757 encouraged the British to imitate her design, yielding the  Southampton and  Richmond-class frigates. The 12-pounder also equipped the castles on razeed ships, where 12 pieces were mounted, and the 22-gun secondary battery of 50-gun fourth-rates. Finally, 30 were installed on the third deck of 90-gun second-rates.


12-pounder long gun, Usage
Profile view of a reproduction aboard Hermione, including the elaborate rigging


12.10
12.10 is a 1919 British silent thriller film directed by Herbert Brenon and starring Marie Doro, Ben Webster, and Geoffrey Kerr. It was the first film made by British & Colonial Kinematograph Company which had ambitious plans to break into the American market. It was made at Walthamstow Studios, and had considerable success on its release.


12.10, Plot
As described in a film magazine, Louis Fernando fails to sell a patent upon which he has spent the better part of his life and drowns himself. His orphaned child Marie (Doro) is adopted by Lord Chatterton (Webster). Geoffrey Brooke (Kerr), who is in the employ of Lord Chatterton, falls in love with Marie. Chatterton's general manager Arthur Newton (Carew) also loves Marie and formulates a scheme whereby he hopes to win her and also acquire the Chatterton fortune. Chatterton becomes suspicious and by a ruse traps Newton and exposes his plot. Marie and Geoffrey are made happy in the end.


12.17×42mm RF, 12.17×42mm RF and its subvariety the 12.17×44mm RF
The 12.17×42mm RF rimfire round was developed by a joint Swedish-Norwegian arms commission, and was adopted by the armed forces of both Sweden and Norway in 1867. It was used in the M1867 Remington rolling-block rifles adopted as new standard rifles by the armed forces of Sweden and Norway the same year. Large numbers of older rifles, both Swedish muzzle-loading Model 1860 and breech-loading Model 1864 and Norwegian breech-loading Kammerlader rifles of various models were also converted to rolling block rifles, chambered for the new standard round.


12.17×42mm RF, 12.17×42mm RF and its subvariety the 12.17×44mm RF
A lengthened version of the round, the 12.17×44mm RF, was adopted by the Norwegian armed forces in 1871. But the two cartridges were interchangeable, and could thus be fired from the same weapons.


12.17×42mm RF, 12.17×42mm RF and its subvariety the 12.17×44mm RF
The round, nominally known as 4 Linjers (actual bore diameter 4.1 Swedish decimal lines or 3.88 Norwegian decimal lines, that is 0.41 Swedish or 0.388 Norwegian inches), had a lead bullet 12.615mm (0.497 in) in diameter, with the diameter of the bore, measured between the lands, being 12.17mm (0.479 inches). It used a copper case.


12.17×42mm RF, 12.17×42mm RF and its subvariety the 12.17×44mm RF
In Swedish service the standard cartridge used a lead projectile (shaped like a Minié ball) weighing 24 g (370 gr). The muzzle velocity fired through a 955mm (37.6 in) rifle barrel was 386 m/s (1,266 ft/s), with a muzzle energy of 1,788 J (1,319 ft/lbf). Fired through a 460mm (18.11 in) carbine barrel the muzzle velocity was 340 m/s (1,115 ft/s), with a muzzle energy of 1,387 J (1,023 ft/lbf).


12.17×42mm RF, 12.17×42mm RF and its subvariety the 12.17×44mm RF
In Norwegian service early rounds had a cast lead projectile weighting 5.85 kvintin (22.8 g/352 gr) and 1 kvintin (3.89 g/60 gr) of gunpowder. Later rounds had a pressed lead projectile weighting 6 kvintin (23.4 g/361 gr) and the gunpowder load was increased to 1.05 kvintin (4.09 g/63 gr).


12.17×42mm RF, 12.17×42mm RF and its subvariety the 12.17×44mm RF
There was also a blank round - an ordinary cartridge case loaded with 54 gr (3.50 g) of gunpowder and closed with a cardboard or cork disc.


12.17×42mm RF, 12.17×44mmR centerfire
A civilian/paramilitary centerfire version of the cartridge, the 12.17×44mmR using a brass cartridge case with the same dimensions as the 12.17×44mm RF, was introduced during the 1870s in both Sweden and Norway. The centerfire cartridge could be fired from both Swedish and Norwegian M1867 military Remington rolling-block firearms with only a minor modification, converting the weapon from rimfire to centerfire and vice versa, which could be done by the shooter in the field provided he or she carried the replacement parts.


12.17×42mm RF, 12.17×44mmR centerfire
The advantage of the centerfire cartridge was that spent cases could be reloaded, making centerfire ammunition significantly cheaper to use than rimfire ammunition, so the 12.17×44mmR also saw extensive use in Swedish paramilitary service, being used by Frivilliga Skarpskytterörelsen ("The Volunteer Sharpshooter Movement"), a voluntary paramilitary organization patterned on the  British Volunteer Force and training civilians in the use of arms, with the units raised intended as local defense units (the first such volunteer "sharpshooter" units were raised in Stockholm in 1860, with the total number of active members throughout Sweden reaching 40,000 in 1865; volunteer "sharpshooter" units were armed with military M1867 rifles modified to use the 12.17×44mmR centerfire cartridge, and wore military-style uniforms).


12.17×42mm RF, Alternative names
The 12.17×42mm RF is also known as "12,17mm patron m/1867" and "12×42RF Swedish Remington Model 1867".The 12.17×44mm RF is also known as "12×44RF Norwegian Remington Model 1871" and "12.7×44RF Norwegian". The 12.17×44mm R is also known as "12×44R Swedish Remington", ".50 Swedish/Norwegian Remington" and "12.7×44R".


12.17×42mm RF, Today
Many Remington Rolling Blocks were converted to use the centerfire 12.17×44mmR cartridge or rebuilt to shotguns. Many of these guns still exist and are still used by black-powder enthusiasts both for competition and hunting. Centerfire 12.17×44mmR cases are available, but a more cost-effective way to acquire cases is to cut .50 Alaskan cases down to 44mm total length.


12.38
"12.38" is a song by American rapper Donald Glover, performed under the stage name Childish Gambino, from his fourth studio album, 3.15.20 (2020). The song features guest vocals by rapper 21 Savage, American singer-songwriter Atia "Ink" Boggs, and American musician Kadhja Bonet. All vocalists on the track, along with Glover and DJ Dahi, wrote the song; the latter two also produced the track.


12.38
Glover sings about a psilocybin-induced trip with a girl, while 21 Savage raps about police harassment. Critics praised the song's comedic narrative and 21 Savage's guest appearance. "12.38" peaked at number 22 on the NZ Hot Singles published by Recorded Music NZ.


12.38, Background and recording
Producer DJ Dahi called the creation of the song an evolving process. Dahi had an initial beat with chords provided by Ely Rise. Kadhja Bonet's vocals were for another track, but were chopped and reused for "12.38". Dahi described the track as having "funky, odd, but feels good" energy. The song was momentarily put to the side, but Gambino continued writing his verse. Rapper 21 Savage recorded his guest verse and American singer-songwriter Atia "Ink" Boggs was invited to co-write on the song. Glover and 21 Savage previously collaborated in 2018 on the former's single "This Is America" and the track "Monster" from the latter's second studio album I Am > I Was.


12.38, Composition and lyrics
Noah Yoo of Pitchfork described the production of "12.38" as a "sensual, minimalistic bounce." The song interpolates André 3000's song "Vibrate". In the song, a girl feeds Glover psilocybin, who is unfamiliar with the psychedelic drug. Sexual tension builds up as his girlfriend keeps texting him, causing his phone to vibrate. Glover uses humorous lines such as "Why your cat looking at me sideways?" in place of a hook and chorus. His verse continues as a beat-by-beat breakdown of the psilocybin use, until he wakes up alone. He name-checks multiple female artists, including Toni Braxton, SZA, and Chaka Khan.


12.38, Composition and lyrics
21 Savage raps about police harassment; he was previously detained by U.S. Immigration and Customs Enforcement in February 2019. 21 Savage also raps about Popeyes' chicken and cartoon character Popeye's spinach. By the end, the song "devolves into spirals of vocal echoes" as a result of the psilocybin trip kicking in.


12.38, Release and promotion
The song originally surfaced under the unofficial title "Vibrate" when Glover streamed 3.15.20 on his website on March 15, 2020. The track was titled "12.38" upon the album's official release on March 22, 2020. Only the tracks "Algorythm" and "Time" have proper names; the rest, such as "12.38", are marked by their respective timestamps. "12.38" was released as a single to urban adult contemporary radio on April 14, 2020, along with "Sweet Thang (24.19)".


12.38, Critical reception
Kitty Empire of The Guardian called the song excellent and described it as having "the feel of narrative fiction". Empire stated that the song "could be an episode of Atlanta," an American comedy-drama television series created by Glover. Rowan5215 of Sputnikmusic called the song hilarious and wrote that Glover "[weaponizes] his full range to spin some The Love Below-style seduction." Okla Jones of Consequence of Sound called the song witty and sonically-pleasing as Glover "taps into his prowess as both a writer and a comic." Jones wrote that 21 Savage's verse had Southern charm and was must-needed. Noah Yoo of Pitchfork praised 21 Savage's "particularly on point" guest appearance. Yoo wrote that as the song ends in spiraling echoes, "it's 21's lyrics you’re left thinking about."


12.7 cm SK C/34 naval gun
The 12.7 cm SK C/34 was a German medium-caliber naval gun deployed on destroyers from 1934 through the Second World War. Some of these guns remained in service until 2003 in the coastal defense units of Norway.


12.7 cm SK C/34 naval gun, Characteristics
The 12.7 cm SK C/34 was used on the Type 34, Type 36 and Type 36B destroyers as well as the sloop Grille, the training ship Bremse and the torpedo boats Leopard and Luchs. They were also intended for the unbuilt Type 38B destroyers, Type 40 torpedo-boats and the Type XI U-boats. These guns were either mounted on single hand worked MPLC/34 mounts, converted 10.5 cm MPLC/28 mounts or in two twin Drh LC/38 mounts for Type XI U-boats.


12.7 cm SK C/34 naval gun, Characteristics
Though in Germany it was designated 12.7-centimeter (5.00 in), all 12.7-cm guns actually had a bore of 12.8 centimeters (5.04 in). The gun could be depressed to -10° and raised to 30°. It had an arc of fire of 360°, meaning that they could rotate a full circle, able to fire at any given point. The gun fired a 28-kilogram (62 lb) high-explosive shell at a muzzle velocity of 830 meters per second (2,700 ft/s) to a range of 17,400 meters (19,000 yd).


12.7 cm/40 Type 89 naval gun
The 12.7 cm/40 Type 89 naval gun was a Japanese anti-aircraft (AA) gun introduced before World War II. It was the Imperial Japanese Navy's standard heavy AA gun during the war.


12.7 cm/40 Type 89 naval gun
The Type 89 was adopted by the IJN on February 6, 1932, and was the primary anti-aircraft gun on new aircraft carriers, battleships and cruisers, most commonly installed in twin gun mounts. As IJN ships were upgraded in the 1930s and 1940s, older AA guns such as 8 cm/40 3rd Year Type naval gun and 12 cm/45 10th Year Type naval guns were replaced with Type 89s.


12.7 cm/50 Type 3 naval gun
The 12.7 cm/50 Type 3 naval gun was a medium-caliber naval gun of the Imperial Japanese Navy used during World War II. It was the standard weapon for Japanese destroyers between 1928 and 1944 (except Akizuki and Matsu classes). It has been credited as a true dual-purpose gun, but this was more a nominal capability than real, as its bag propellant and need for hand ramming required the gun to be loaded at elevation angles of 5–10°.


12.7 cm/50 Type 3 naval gun
This dropped its rate of fire to a relatively slow 5–10 rounds per minute, and its training speed of only 6° per second meant that it had a great deal of difficulty engaging enemy aircraft with any chance of success. After the end of World War II the gun remained in service on the two Japanese destroyers ceded to the Soviet Union and the Republic of China as war reparations.


12.7 cm/50 Type 3 naval gun, Description
The 50-caliber 12.7 cm (5.0 in) Type 3 gun was of built-up construction, originally with three and later two layers with the usual breech ring and breech bush. It used a Welin interrupted screw breech. The shell was fuzed manually on the loading tray before being rammed by hand and could only be loaded at elevations between 5° and 10°. All mounts used pusher-type shell hoists, but the powder bags were passed by hand.


12.7 cm/50 Type 3 naval gun, Description, Mountings
These guns were first used in the twin gun Model A turret on the revolutionary  Fubuki-class destroyers. These were the first weatherproof, splinterproof and gas-proof enclosed gun turrets ever mounted on a destroyer. Guns in twin mounts were in individual cradles and could elevate separately. All twin gun mounts weighed approximately 32 tonnes (31 long tons; 35 short tons). All mounts could traverse at 6° per second and could elevate at a rate between 6° and 12° per second although speeds up to 27° per second have been reported.


12.7 cm/50 Type 3 naval gun, Description, Mountings
The twin gun Model A mount was fitted with a 9–12-millimetre-thick (0.35–0.47 in) gun shield. Its guns could depress −5° and elevate to +40°. These mounts were deployed on the first ten Fubuki-class destroyers. The twin gun Model B mount had its elevation increased to 75° and was fitted in the rest of the Fubuki-class as well as the  Akatsuki-class destroyers. In order to save weight its gun shield was reduced to 3.2 mm (0.13 in) in thickness, but this proved too thin to withstand heavy seas and was later reinforced.


12.7 cm/50 Type 3 naval gun, Description, Mountings
The first four of the  Hatsuharu class used the Model B mod 2 mount although how it differed from the earlier Model B mount is unknown. The last two of the Hatsuharu class, the  Shiratsuyu,  Asashio, and  Kagerō-class destroyers used the Model C which reduced its maximum elevation to 55°, but could depress to −7° and was supposedly lighter than earlier models The Model D used by the  Yūgumo-class and the Shimakaze destroyers retained the depression limit of the Model C, but elevation returned to the 75° of the Model B.


12.7 cm/50 Type 3 naval gun, Description, Mountings
The Type A single mount could depress −7° and elevate to +75°, but the Type B reduced the maximum elevation to 55°. Both mounts weighed approximately 18.5 tonnes (18.2 long tons; 20.4 short tons). The Type A was fitted on the Hatsuharu class and the Type B on the Shiratsuyu-class destroyers.


12.7 cm/50 Type 3 naval gun, Description, Ammunition
The gun normally fired a 23 kg (51 lb) high-explosive shell, an illumination shell or an incendiary shrapnel round (sankaidan) intended for anti-aircraft use. All of these shells weighed 23 kg (51 lb) and used 7.7 kg (17 lb) of 30 DC propellant. After 1943, a flat-nosed anti-submarine shell also became available. This had a minimum range of 800 metres (870 yd) and a maximum range of 4,300 metres (4,700 yd). A new, heavier, but more streamlined, high-explosive projectile with a range of 23,025 metres (25,180 yd) was under development when the war ended.


12.7x55mm
The 12.7x55mm cartridge is a Russian-made .50 caliber cartridge used in both pistols and rifles (although one of each has been made so far). It was developed without a parent case, and as such, was made from scratch.


12.7x55mm, Purpose
It is intended as an armor-piercing handgun/rifle cartridge. It comes in jacket soft point, hollow point and full metal jacket variants.