Background {#Sec1}
==========

Norovirus is considered the major cause of acute gastroenteritis among all age groups worldwide \[[@CR1]--[@CR4]\]. The majority of human norovirus can be classified into two genogroups, I (GI) and II (GII). Norovirus is highly infectious and can be transmitted in various ways including contact with infectious individuals or contaminated environment and consumption of contaminated food. Food contamination can occur directly with human fecal matter at the source of production or with unhygienic handling by food workers excreting the virus \[[@CR5]\]. In foodborne norovirus outbreaks for which investigators reported the source of contamination, 70 % were caused by infected food workers \[[@CR6], [@CR7]\].

Kinmen County is one of Taiwan's offshore islands located off the southeastern coast of mainland China with a population of less than 128000. The main industry on the island is liquor production. On 7 February 2015 the Kinmen Health Department was notified by a local hospital of nine gastroenteritis cases among employees from a large distillery company. All had attended "Weiya"---a traditional annual event for employers to treat employees to a banquet and thank them for their hard work throughout the year---on 6 February afternoon. The lunch banquet was held in two restaurants (A and B) and attended by more than1400 employees. The lunch included ten courses and the plates were served at the table in succession by the servers in the restaurants. The food items served in the banquet were the same in two restaurants but were mainly prepared and cooked by restaurant A. Preliminary investigation by the Kinmen Health Department found that more than 450 employees of the distillery from different departments experienced gastrointestinal illness by 8 February and all affected had attended the lunch banquet. Food served at the lunch banquet was suspected as the vehicle of transmission. An investigation team from the Kinmen Health Department and Taiwan Field Epidemiology Training Program was established to identify the etiological agent and factors associated with food contamination.

Methods {#Sec2}
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Epidemiological investigation {#Sec3}
-----------------------------

List of lunch attendees and ill persons were provided by the distillery. Three departments of the distillery, consisting of 520 employees, were purposely selected and therefore lunch attendees in restaurants A and B could be included for analytic study. A semi-structured questionnaire was designed to ask about the attendee's food and beverage consumption in the banquet, as well as demographic and clinical data. The questionnaire was distributed to all the employees from three selected departments who had attended the lunch banquet. The participants were asked to complete and return the questionnaire to the distillery by 13 February.

A case--control study was performed to determine whether certain foods were associated with illness. An outbreak case was defined as a lunch attendee reporting at least three of the following symptoms of nausea, vomiting, diarrhea or abdominal pain within 72 h of eating at the banquet. Controls were defined as lunch attendees who had not displayed any of the above symptoms during the same time period.

Data collected were analyzed using Excel, version 2010 (Microsoft) and Epi Info™ 7. We conducted univariate analyses to compare characteristics and exposure of cases and controls using the Chi-square or Fisher's exact test for categorical variables and the Wilcoxon rank-sum test for continuous variables. All comparisons were two-tailed and a *p*-value \<0.05 was considered significant. Odds ratios (OR) with 95 % confidence intervals (CI) were calculated individually for all food items and beverages. Multivariable analysis was performed using logistic regression. The multivariable model was constructed using all variables that were significantly associated with illness in univariate analysis (*P* \< 0.05).

Human microbiological investigation {#Sec4}
-----------------------------------

Following notification of the outbreak, vomitus and rectal swabs were collected from lunch attendees with symptoms. Fresh stool samples were requested from food handlers responsible for food preparation and cooking. These specimens were sent to the Taiwan Centers for Diseases Control for bacterial and viral tests. Bacterial tests included cultures for common enteropathogens (*Salmonella* spp., *Shigella*, *Vibrio cholerae*, *Vibrio parahaemolyticus*, *Staphylococcus aureus*, *Bacillus cereus*) and toxin of *Staphylococcus aureus*. Viral tests included reverse transcription-polymerase chain reaction (RT-PCR) tests for detecting norovirus and enzyme-linked immunosorbent assay screening of rotavirus as previously described \[[@CR8], [@CR9]\]. Those norovirus PCR-positive specimens were then sequenced and analyzed using an ABI 3130 sequencer (Applied Biosystems, Foster City, CA, USA). Multiple nucleotide sequences were aligned and analyzed phylogenetically using MEGA 4.0 software.

Food and environmental investigations {#Sec5}
-------------------------------------

Health officers from the Kinmen Health Department inspected the two restaurants on 8 February. Environmental sampling using swabs was performed on food preparation surfaces to detect contamination. Food sampling was performed on the leftovers obtained from the restaurant A. Environmental surface and food samples were sent to the Taiwan Food and Drug Administration and tested for *Salmonella* spp., *Bacillus cereus*, *Vibrio parahaemolyticus*, *pathogenic Escherichia coli* (*E.coli*), *Staphylococcus aureus* and toxin of *Staphylococcus aureus*. Water samples collected from the kitchen of restaurant A were tested for total coliforms and fecal coliforms (*E. coli*).

The investigation team undertook another environmental assessment on 11 February, which included a detailed examination of menus, food items, preparation methods, food hygiene practices and work assignments. Food storage facilities, food preparation, kitchen facilities, water supply and toilets were also inspected. The attendance record of staff members was reviewed to identify any sick leave before or after the banquet.

Results {#Sec6}
=======

Epidemiological investigation {#Sec7}
-----------------------------

Questionnaires were returned from 376 attendees, out of total 464 questionnaires distributed (response rate 81 %). Complete data were available for 363 attendees, of which 169 persons met the case definition and 111 met the control definition. The remaining 83 respondents reported illness that did not meet the case definition and were excluded from the analysis.

For both cases and controls the median age was 41 years (range: 23--65 in cases and 26--76 in controls) (*P* = 0.83). The proportion of male was significantly lower among cases than controls (57 % vs. 75 %, *P* = 0.004). Of 169 case patients, 115 (68 %) ate lunch in the restaurant B, compared with 35 (32 %) of 111 control subjects (*P* \< 0.001). The most frequently reported symptoms among cases were diarrhea (71 %) and abdominal pain (62 %), followed by vomiting (55 %), nausea (41 %) and chillness (48 %). The illness onset peaked during 12:00--23:59 on 7 February (Fig. [1](#Fig1){ref-type="fig"}). The median time between eating and illness onset was 29 h (range 4--72 h). None of these cases required hospitalization.Fig. 1Cases of outbreak of norovirus gastroenteritis among distillery lunch attendees, by date and hour of symptom onset in 12-h interval (*n* = 169)

In univariate analyses, all foods except 'Buddha jumping over the wall' (a traditional Chinese dish with seafood, pork and vegetables cooked in eastern jar), Guabao (steamed sandwich), cherry tomato and sliced orange were significantly associated with illness (Table [1](#Tab1){ref-type="table"}). Consumption of beverages was not associated with illness. In the multivariable logistic regression model controlling variables including gender, restaurants and food items showing statistical evidence (*P* \< 0.05) in univariate analysis, pork liver in cold appetizers (adjusted odd ratio \[aOR\] 3.23; 95 % confidence interval (CI): 1.26--8.30) and lamb chops wrapped in lotus leaves (aOR: 3.98, 95 % CI: 1.74--9.11) were independently associated with illness (Table [2](#Tab2){ref-type="table"}).Table 1Food items associated with illness by univariate analysisFood itemCases (*n* = 169) (%)Controls (*n* = 111) (%)OR (95 % CI)*P* valueCold appetizer---fried fish157 (92.9)88 (80.0)3.27 (1.54--6.93)0.001Cold appetizer---salted jellyfish130 (77.4)68 (61.3)2.16 (1.28--3.66)0.004Cold appetizer---pork liver157 (92.9)81 (73.0)4.85 (2.36--9.97)\<0.001Cold appetizer---spring roll144 (85.7)78 (70.3)2.54 (1.40--4.60)0.002Cold appetizer---sliced fried duck129 (77.3)66 (59.5)2.31 (1.37--3.90)0.02Buddha jumping over the wall^a^156 (92.3)97 (87.4)1.73 (0.78--3.84)0.17Steamed rice cake with shrimps159 (94.1)94 (84.7)2.88 (1.26--6.54)0.01Stewed bamboo shoot161 (95.8)98 (88.3)3.05 (1.18--7.91)0.02Steamed fish147 (87.5)83 (74.8)2.36 (1.26--4.42)0.006Lamb chops, carrots, radish wrapped in lotus leaves141 (83.9)65 (59.1)3.62 (2.06--6.33)\<0.001Salted boiled shrimps145 (86.3)72 (64.9)3.41 (1.90--6.15)\<0.001Braised pork130 (78.3)66 (60.0)2.41 (1.42--4.09)0.001Guabao (steamed sandwich)141 (83.4)83 (74.8)1.70 (0.94--3.06)0.08Coriander92 (54.8)45 (40.5)1.78 (1.09--2.89)0.02Mashed garlic100 (59.5)46 (41.4)2.08 (1.28--3.38)0.003Rib soup with Chinese yam132 (78.6)73 (65.8)1.91 (1.11--3.27)0.02Butter Swiss roll120 (71.4)64 (57.7)1.84 (1.11--3.04)0.02Cherry tomato92 (54.4)49 (44.1)1.51 (0.93--2.45)0.09Sliced orange96 (57.1)50 (45.1)1.63 (1.00--2.64)0.05OR, odds ratio; CI, confidence interval^a^a traditional Chinese dish with seafood, pork and vegetables cooked in eastern jarTable 2Food items associated with illness by multivariable logistic regression analysisFood itemAdjusted OR\* (95 % CI)*P* valueCold appetizer---pork liver3.23 (1.26--8.30)0.01Lamb chops, carrots, radish wrapped in lotus leaves3.98 (1.74--9.11)0.001OR, odds ratio; CI, confidence interval\*adjusted for food items showing statistical evidence (at *P* \< 0.05) on univariate analysis, genders and restaurants

Human microbiological investigation {#Sec8}
-----------------------------------

Eight lunch attendees submitted one vomitus sample and seven rectal swabs. The vomitus was negative for bacteria and virus testing. All rectal swabs were negative for bacterial testing. The virological result of stool in lunch attendees was not available because fresh stool samples were not requested at the time of collection. Eight of 12 restaurant food handlers submitted fresh stool samples, of which all were negative for bacterial testing but two were positive for norovirus GI.6. These two samples were retrieved from two asymptomatic food handlers who were on duty at the lunch banquet---one responsible for cooking and cutting pork liver and the other responsible for arranging the cold appetizers including pork liver on the serving platter. The vegetables (carrots and radish) served with lamp chops were also cut by the second food handler.

Food and environmental investigations {#Sec9}
-------------------------------------

The initial environmental health inspection on 8 February revealed the violation of food safety regulatory requirements. Poor hygiene in the kitchen, inadequate food storage and improper waste disposal were identified. Investigation showed that kitchen staff used tap water for cooking but used untreated ground water to wash food ingredients and utensils. Subsequent sampling of tap water and ground water from the kitchen of restaurant A tested negative for total coliforms or fecal coliforms. Eleven food samples retrieved from the restaurant A were negative for bacterial testing. Four environmental samples (retrieved from chopping boards of restaurant A and B) were negative on bacterial analysis.

During the second inspection on 11 February, the investigation team found that a separate toilet was placed in the kitchen of restaurant A for staff use only but no hand wash sink was seen inside. The manager of restaurant A claimed that food workers might wash their hands using sink in the kitchen or use toilets for customers. Interview also indicated that food items were cooked 3 h before serving; some were reheated by steamers and some were not. Regarding the health status among staff before the outbreak, the manager of restaurant A denied any illness. However, reviewing the attendance records revealed that one server had taken a week's leave to care for her child with gastroenteritis before the banquet. The two restaurants did not adhere to the regulations of annual training and medical check-ups for food workers.

Control measures {#Sec10}
----------------

The restaurant A was closed on 8 and 9 February for cleansing its environment. No more cases were noticed since 10 February. On 11 February, while reviewing the clean-up procedures after the incident, investigation team discovered that the restaurants had used bleach solution with inappropriate concentration. The investigation team instructed the restaurants to disinfect according to the Taiwan Centers for Disease Control guidelines for environmental cleaning and disinfection of norovirus \[[@CR10]\]. Food workers were also asked to reinforce proper hand hygiene through washing with soap and water.

Discussion {#Sec11}
==========

The outbreak of acute gastroenteritis, reported on 7 February 2015 on the distillery in Kinmen, Taiwan, was presumed to be caused by norovirus. Most of the affected persons became symptomatic within 24--48 h of having the lunch with the predominant symptoms with diarrhea, abdominal pain and vomiting. The epidemic curve of this outbreak suggested a common point source and the case--control study identified pork liver in cold appetizers and lamb chops wrapped in lotus leaves being the most likely vehicles of the transmission. Since norovirus is relatively resistant and can survive temperatures as high as 60 degrees, consumption of ready-to-eat or not thoroughly cooked foods with norovirus contamination is recognized to be high risk of infection \[[@CR11]\].

The two asymptomatic food handlers who tested positive for norovirus were the likely source of this outbreak at the lunch. A Japanese study on norovirus-associated gastroenteritis in food-catering settings has shown high rates of norovirus infection in asymptomatic food handlers and shedding a similar number of virus particles as those who were symptomatic \[[@CR12]\]. The presence of norovirus RNA on the hands of food handlers demonstrated that the virus could be disseminated by virus-shedding food handlers \[[@CR13]\]. In this outbreak, it would appear that asymptomatic food handlers contaminated multiple foods during their preparation. Lack of hand sink in the kitchen toilet implied that the food handlers may not adhere to hygienic regulations, such as washing hands after toilet use. Food items which were handled manually and not heated before consumption could subsequently become contaminated from infected food handlers \[[@CR11]\]. The time pressure resulting from the large numbers of attendees may also have contributed to a lapse in personal hygiene during preparation of meals and facilitate norovirus transmission from viral-shedding food handlers.

Food handlers have been implicated in norovirus foodborne outbreaks. In the US, 70 % foodborne norovirus outbreaks were attributed to infectious food workers \[[@CR6], [@CR14]\]. Symptomatic food handlers are required not to work with food until 48 h after resolution of symptoms \[[@CR15]\]. The food handlers in this outbreak were asymptomatic. Although it was possible that food handlers did not disclose the illness honestly, they might have asymptomatic infection \[[@CR16]--[@CR18]\], which was frequently detected in food handlers with reported prevalence ranging from 1 % to 12 % \[[@CR4], [@CR12], [@CR19]--[@CR21]\]. In such circumstance, it would be difficult to prevent outbreaks by monitoring the health status of food handlers. Therefore, following strict hygiene practices such as proper hand washing and wearing gloves while preparing foods, especially hand-prepared and ready-to-eat foods, is crucial to minimize the risk of food contamination from food handlers with asymptomatic norovirus infection.

The environmental inspection showed no hand sink in the kitchen toilet of the restaurant. This flaw may result in suboptimal hand hygiene practices of food handlers and contamination of food. A study of food worker hand hygiene identified that hand washing was more likely to occur in restaurants with more than one hand sink and with a hand sink in the observed worker's sight \[[@CR22]\]. Apart from training of safety food preparation practice, multidisciplinary approaches including increased accessibility of hand washing facilities would improve food handlers' hand hygiene compliance \[[@CR23]\].

Our investigation has at least the following limitations. First, although the survey was done within 1 week after the banquet, we could not rule out the introduction of information bias due to the retrospective nature of the study. Second, we were unable to confirm the presence of norovirus in lunch attendees because of lack of stool specimen collection for viral study. However, predominant symptom of vomiting and incubation period of 24--48 h accord with Kaplan criteria for norovirus outbreak \[[@CR24]\]. Detection of norovirus in food handlers suggests that the food handlers are likely the common origin of cases. Finally, food handlers might have not disclosed gastroenteritis symptoms to the investigation team because of fear of negative consequences \[[@CR20]\]. Therefore, we could not determine whether norovirus shedding in food handlers was primarily due to asymptomatic infection. This information would have helped elucidate the association between asymptomatic excretion in food handlers and outbreaks. In-depth interviews on food handlers with reassurance that they will not suffer loss of pay if they report illness could facilitate symptom reporting.

Since norovirus outbreak can be difficult to distinguish from outbreaks of other etiologies, it is recommended to submit stool for bacterial and viral testing simultaneously so pathogen of outbreaks and chain of transmission are rapidly identified and control measures could be applied accordingly. Guidance from the Taiwan Centers for Disease Control for public health communities to collect stool specimens for foodborne outbreak was revised shortly after this outbreak \[[@CR25]\].

Conclusion {#Sec12}
==========

This outbreak was a norovirus gastroenteritis outbreak associated with asymptomatic food handlers. To reduce food contamination, strict general hygiene practices, such as thorough hand hygiene and use of gloves and protective clothing in kitchen areas should be implemented. More attention should be paid to the toilet facilities for food workers to reinforce hand hygiene practices and prevent foodborne outbreak.

Ethics approval and consent to participate {#Sec13}
------------------------------------------

This outbreak investigation was reviewed by Taiwan Centers for Disease Control and approved as part of the legally authorized mandate. It was therefore considered a minimal risk research, which was exempted from human subject review and does not require informed consent.

Availability of data and materials {#Sec14}
----------------------------------

The dataset supporting the conclusions of this article is available in the FigShare repository <https://dx.doi.org/10.6084/m9.figshare.3144727.v2>.

**Competing interests**

The authors declare that they have no competing interest.

**Authors' contributions**

MYC participated in the questionnaire design, data analysis, and manuscript preparation. WCC contributed to the questionnaire design and data interpretation. PCC and SWH participated in and supervised the data collection. YCL contributed to the manuscript reviewing and editing. All authors read and approved the final manuscript.

We would like to thank the staff of the distillery involved in this outbreak for their help with collection of data for this study. We are especially grateful to the staff from the Kinmen Health Department for facilitating the outbreak investigation. We also thank Ms Fang-Tzy Wu and the staff of the Center for Research, Diagnostics and Vaccine Development, Centers for Disease Control, Taiwan for undertaking human microbiological examinations.


Let's Talk! with Fr. John Johnson

The free exercise of religion as established by the First Amendment of the U.S. Constitution has always been among the most treasured of American rights. Lately, it has been the subject of debate and heightened scrutiny. The American Bishops have argued that certain provisions of the Affordable Care Act (a.k.a. Obama Care) are in direct violation of the First Amendment insofar as they would require Catholic institutions to provide certain health benefits that stand in opposition to Catholic ethical teaching.

September 18: What is a Law? Liberalism and American Jurisprudence
September 26: What is Freedom? Modern Ideas Regarding “Free-Will”
October 3: What is Religious Freedom? Comparing the First Amendment to
Vatican II’s “Declaration on Religious Freedom”


Q:

Cannot change Drush version from 6.1.0 to 7.0

I am trying to update my version of Drush to include the Omega commands. For this I think I need 7.0. I have run composer global require drush/drush:7.0.0-alpha5 and this installs the package but when I check drush version it still says Drush Version   :  6.1.0 How do I change my version of Drush to 7.0?

A:

I found a way to do this using brew install --HEAD drush followed by brew switch drush HEAD The full article where I found this is here, under Installing Drush 7.x dev


The ins and outs of amazing Spanish food, as told by two students who studied abroad.

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As my experience abroad in Spain comes to a close, I've been reflecting on the amazing times I've had, the great friends I've met, and of course, the delicious food I ate. Now scratch everything you know about Spanish food. Sure, you can get decent paella in Castilla y Leon, but not many people know where to get the best. Here are a few tips on where to find the best places to get your Spanish food fix, depending on the plate you desire.

1. Paella

Summer Tuman

When you think of Spanish food, you probably think of paella first, like this shrimp paella. The most famous of Spanish foods is the one with the most flavor. You can get paella almost anywhere across the country, but the best paella is in Valencia. This is because of La Albufera, a body of water in the province of Valencia that gives the land the perfect texture for growing rice. Also, because of its location next to the Mediterranean, the fresh Valencian seafood makes for a great dish of seafood paella.

2. Jamón Iberico (Iberian Ham)

Emily Chaisson

In Spain there are many different types of jamon: jamon serrano, jamon curado, jamon reserva and of course, the most famous, jamon iberico. While you might think you're getting the best jamon iberico in the Spanish capital of Madrid, you'd be mistaken. The best jamon iberico comes from the province of Salamanca (represent!) in Castilla y Leon; more specifically the town of Guijuelo. The pigs in Guijuelo are called "Pata Negra", basically black-footed. What makes this type of jamon so rich is the fact that the pigs are given acorns as a part of their diet. Yes, acorns. And Guijuelo has a ton of them.

3. Gazpacho

Summer Tuman

Translated to English as "cold tomato soup," gazpacho is definitely a fan-favorite Spanish dish. But what you didn't know is that the best gazpacho comes from the region of Andalucia, and that it is usually only eaten in the summertime. That's because it gets so hot in Andalucia, and the locals need something to cool themselves down. Queue the gazpacho. Try making your own using this recipe.

4. Cava (Spanish Champagne)

Summer Tuman

Cava is a champagne that is from the Catalunya region. It's a very popular drink to have in Barcelona and is super cheap (just like every other type of wine in Spain).

5. Sidra (Hard Cider)

Emily Chaisson

La Sidra, or Spanish hard cider, is commonly enjoyed during Navidades (Christmas season). But for the rest of the year it is a typical drink in the province of Asturias in the north of Spain. Make sure you don't miss the show!

6. Fabada

Image from WikiCommons

Another typical dish of Asturias is Fabada. Known for its density, this stew is filled with beans, bacon, chorizo, ham, and sausage. It's commonly eaten during the winter months to help keep people warm. Talk about filling.

Below are some typical Spanish foods you can get virtually anywhere. These are important delicacies that everyone must try, no matter which Spanish city or province you find yourself in.


1. Field of the Invention
The present disclosure is related to measuring an aspect of a load supported by a container. More particularly, the present disclosure is related to measuring a size of a load in a tub or basket that is subject to a rotational acceleration.
2. Description of Related Art
Vertical axis washing machines, also known as top loading washing machines, represent a large portion of the overall washing machine consumer market in the United States. Horizontal axis washing machines represent a smaller segment of the United State market and abroad typically represent a larger portion of the overall washing machine consumer market.
Most vertical and horizontal axis washing machines include a spin cycle for removing water and/or detergents from the laundry using centrifugal force and spinning a wash load tub, also referred to as a laundry tub (“tub”) or basket. During a typical spin cycle, the motor, typically an induction motor, of the washing machine spins the tub at relatively high speed(s).
Historically induction motors used in washers have been single phase induction motors or PSC induction motors. More recently 3-phase induction motors, have been used in some commercially available washers. The 3-phase motors in washers for home use are typically powered by standard single phase AC household electric power. As part of a 3-phase induction motor washing machine, a circuit associated with the motor converts the single phase AC household electric power to three phase power; the three phase power is better at motor starting and operates more efficiently than single phase power.
A simplified explanation of an induction motor, ignoring losses follows: The induction motor has a rotor with a short-circuited winding inside a stator with a rotating magnetic field. The flux from the rotating field induces a current flow in the rotor. The frequency of the current flowing is equal to the difference between the rotational speed of the stator field and the rotational speed of the rotor. This difference in speed, or frequency, of the stator magnetic field and the rotor magnetic field is known as the slip.
The rotor current causes a rotor magnetic field, which is spinning relative to the rotor at the slip frequency and relative to the stator, at the stator applied frequency. The interaction between rotor magnetic field and the stator magnetic field generates a torque in the rotor.
A washing machine wash cycle has various modes such as fill, drain and spin, agitation, and spin. Load sensing can occur before, during or after various segments of the wash cycle. Knowing the amounts of water and detergent used in the wash cycle can be helpful in providing an efficiently run washing machine.
The weight of a load of clothes loaded into a clothes washer for washing is an important parameter in determining the proper amount of water and detergent to be used for the wash cycle. Large clothes loads require larger quantities of water than do small loads. Better clothes washability and significant water and energy savings can be achieved when the proper amount of water is filled into the washer tub for a given clothes load. Too much water or detergent is wasteful, and too little of either will generally adversely affect the effectiveness of the washing, and may result in increased energy consumption due to a higher load on the motor as a result of the inability of the clothes to move freely in the water. Additionally, load size may aid in determination of max spin speed and degree of load imbalance. For example, a 1 lb. load with 0.5 lb. imbalance may be more severe than a 10 lb. load with 0.5 lb. imbalance.
Techniques or methods of estimation of the load of clothes loaded into a washer employed by the washer itself are desirable in that it eliminates guesswork on the part of the machine operator which can lead to improper water fill or use of an improper amount of detergent. Knowing load size can also prevent damage to the washer by limiting max speed. Prior art techniques include displacement sensors mounted at tub springs; magnet and coil pickup sensing relative displacement of tub from chassis; and ultrasonic transducers. Prior art washing machines that use sensing hardware are costly due to the need for dedicated sensing hardware.
Another technique involves determining a load size by measuring a time required for a load to change speed when a known stimulus is applied such as a positive speed step or coasting. While suitable for its intended purposes, this method is not particularly suitable for horizontal axis washers that have two main sources of friction.
A first source of friction in a horizontal axis washer involves clothes rubbing against a door and/or a window of the washer. As the clothes spin around in the machine, they rub against the window causing friction. This friction increases as more clothes are added to the load.
A second source of friction (and a major source in a vertical axis washer) involves machine friction that is caused by bearings, belt tension and other variables of the washer. Machine friction may also change over time as the belt tension weakens or the bearings begin to wear out.
Accordingly, there is a need for a washing machine that overcomes, alleviates, and/or mitigates one or more of the aforementioned and other deleterious effects of prior art washing machines.


SUPPORT JULIAN ASSANGE

Wednesday, April 20, 2016

Thierry Meyssan -- Turkish Supremacy

Turkish Supremacy

by Thierry Meyssan

The Turkish President, Recep Tayyip Erdoğan, has repeatedly brought up the option of depriving a tenth of the population of their Turkish nationality. These are far from declarations issued by a court. We have here the application of the supremacist theory of Millî Görüş, an Islamic organization, of which he was one of the directors and which he claims to have left. If such an option were to be implemented, it would open a new regional war.

Leaving the Mosque of the Faculty of Theology, Istanbul, (İlahiyat Fakültesi Camii) after Friday prayer, on 8 April 2016, President Erdoğan has confirmed his desire to strip those who support armed resistance of their nationality.

Under international law, everyone has the right to protection from a state. However, there are around 10 million stateless persons in the world. These include 4.5 million Palestinians, 1 million Burmese Muslims, 700 000 Burkinabé refugees in Ivory Coast, 500 000 Thaï and 270 000 Russians in Lithuania. According to the UN High Commissioner for Refugees, Antonio Guterres, « Statelessness can mean a life without education, without health care or a formal job, a life without freedom of movement, without any hope or prospects for the future ».

However, by espousing a supremacist ideology, Recep Tayyip Erdoğan opens the door to extinguishing the nationality of any Turkish national who is not ethnically Turkish and for Turks that support them. Last July, he has deliberately relaunched the civil war, challenging his promise of equality for everyone. He has launched military operations, ordered the cease-fire in different Kurdish localities, seized Christian churches, and finally « neutralised 5 000 terrorists » (sic).

Need we recall that while a number of Kurds are well-integrated in big towns in the West of the country, the majority are relegated to poor regions and their culture is again being trampled on? Must we recall that while several Christian patriarchs are living in Turkey, the law forbids them building churches there?

Westerners who, blinded by their hatred of Syria, support the Turkish expansion and finance the war against the Syrian people, hardly reacted when on 5 April, he evoked the possibility of stripping those voting for HDP of their nationality. According to them, Mr. Erdoğan, who made his case before the Bar Council, is prepared to threaten jurists that challenge his policy. Furthermore, his Prime Minister, Ahmet Davutoğlu, on his trip to Europe, has assured that it only an avenue.

However on 7 April, on receiving officers of the National Police, M. Erdoğan was threatening this time the followers of his former ally, Fethullah Gülen, whom he accuses of being « terrorists » because they refuse to condemn the Kurdish resistance.

Questioned by journalists on leaving Friday Prayer on 8 April, he clarified his thinking:« I meant that all those that are involved in terrorist acts or who support terrorism must be sanctioned (…) they are not fit to be Turkish citizens. They are already in search of another citizenship or of the status of statelessness. It is unacceptable for a citizen of the Turkish Republic to betray Turkey, the Turkish homeland, or the Republic of Turkey. I do not think it right for those who betray the Turkish Republic to retain their citizenship», he responded.

Thus President Erdoğan envisages stripping of their nationality the 5 million voting for HDP, most of whom are from minority descent, and 1 million who are Sunnis of Hizmet, the movement of Mr. Gülen. If such a disaster had to happen, it would have an effect comparable to the Nakba and would necessarily set off a long armed conflict in the region.

assange

At midday on Friday 5 February, 2016 Julian Assange, John Jones QC, Melinda Taylor, Jennifer Robinson and Baltasar Garzon will be speaking at a press conference at the Frontline Club on the decision made by the UN Working Group on Arbitrary Detention on the Assange case.


The present invention relates generally to optical components and systems, and specifically to diffractive optical elements and optical phase elements.
Optical imaging systems using lenses or materials transmitting light in general have to deal with the problem of dispersion of the light. Dispersion is the change of light velocity with wavelength, and dispersion causes chromatic aberrations in the optical system by creating different refractive indices and different phase changes for different wavelengths.
The phase delay xcfx86 in light of wavelength xcex introduced by a thickness d of material of refractive index n is given by:                     φ        =                                            2                            π                        λ                                          (                          n              -              1                        )                              d                                              (          1          )                .
Diffractive systems, for directing and focusing beams of light, are well-known in the art, as described, for example, by Francis Jenkins and Harvey White in Fundamentals of Optics, Fourth Edition, pp. 385-386 (1981), which is incorporated herein by reference. The theory of diffractive optical elements (DOEs) is further described, for example, by Nieuborg, et al., in an article entitled xe2x80x9cPolarization-Selective Diffractive Lenslet Arrays,xe2x80x9d published in European Optical Society Topical Meeting Digest Series, Vol. 5 (1995), which is also incorporated herein by reference. DOEs are generally highly dispersive.
Zone plates are a well-known type of DOE, typically comprising concentric rings having radii proportional to the square roots of the whole numbers and a phase retardation varying by xcfx80 between neighboring rings. When a beam of collimated light is incident on the zone plate, it will be diffracted to a focal point. Like other DOEs and computer-generated holograms known in the art, however, zone plates known in the art are highly chromatically dispersive.
It is an object of the present invention to provide methods for designing and producing diffractive optical elements having a desired wavelength dispersion.
It is a further object of the present invention to provide optical elements designed and/or produced in accordance with these methods.
In one aspect of the present invention, diffractive optical elements are designed and produced so as to be substantially achromatic, i.e., so that their dispersion is effectively minimized.
It is another object of the present invention to provide diffractive optical elements which compensate for chromatic aberrations. Thus, in one aspect of the present invention, diffractive optical elements are applied to a refractive element, such as a lens, to reduce or remove the chromatic aberrations present because of the dispersive properties of the refractive element.
It is a still further object of the present invention to provide an aberration-corrected, diffractive optical element and a method for producing same for a wideband light source.
In preferred embodiments of the present invention, a DOE comprises first and second gratings substantially in mutual registration. The gratings are made of respective first and second materials having respective first and second refractive indices. The dimensions of the gratings, in particular their thicknesses, are chosen so as to give a desired value of wavelength dispersion and/or phase retardation. Preferably, the refractive indices and the dimensions of the gratings are chosen so as to reduce or minimize chromatic aberrations produced by the DOE or by an optical system including the DOE. Such embodiments differ from DOEs known in the art, which typically are designed for a narrow wavelength range and are highly wavelength dispersive.
In some preferred embodiments of the present invention, a DOE is formed on a surface of a lens by etching the first grating into the surface of the lens, overlaying the grating with the second material having a different refractive index from that of the lens, and then etching the second grating into the second material, in registration with the first grating. Alternatively, the second material may first be overlaid on the surface of the lens, and then both the first and second gratings may be etched simultaneously. The DOE preferably corrects for the chromatic dispersion of the lens.
In other preferred embodiments of the present invention, the DOE is formed on a surface by overlaying the surface with a layer of the first optical material, overlaying the first optical material with a layer of the second optical material, and etching the gratings in registration into both optical materials.
In still other preferred embodiments of the present invention, a DOE is formed by etching the first grating into a first surface of a flat plate formed from two materials having different refractive indices, and the second grating is etched in registration with the first grating into the second, opposite surface of the flat plate. DOEs in accordance with these preferred embodiments may be designed to function as substantially dispersionless diffraction gratings or diffractive focusing elements.
In still other preferred embodiments of the present invention, a DOE is formed by combining in registration a plurality of DOEs, each DOE of the plurality being formed as described above.
In some preferred embodiments of the present invention, the DOE is generated by computer calculation and fabricated, alternatively or in combination, by a lithographic process or a plasma-etch process.
The principles of the present invention may thus be applied both in diffractive optical systems and in hybrid systems that mix diffractive and refractive optics, using any suitable methods of design and fabrication known in the art. Although the preferred embodiments described herein relate primarily to achromatization of such optical systems, the principles of the present invention may be applied more generally to control the chromatic response of such systems in substantially any desired manner, for example, to create a desired chromatic dispersion.
Although preferred embodiments are largely described herein with reference to optical wavelengths of radiation, it will be appreciated that similar embodiments of the present invention may generally be constructed utilizing materials operating at non-optical wavelengths such as ultraviolet, infrared, microwave and radio wavelengths.
Furthermore, although preferred embodiments are described herein with reference to two layers of gratings, it will be appreciated by those skilled in the art that similar preferred embodiments may generally be constructed using additional layers of gratings.
There is therefore provided, in accordance with a preferred embodiment of the present invention, a method for producing a diffractive optical element, comprising forming first and second gratings, substantially in mutual registration, of respective at least first and second optical materials, such that for predetermined two or more wavelengths, the diffractive optical element has phase retardations in a desired mutual relation, thereby avoiding the generation of chromatic aberrations.
The invention further provides a diffractive optical element, comprising first and second optical materials in which respective first and second phase gratings are formed substantially in mutual registration, such that for predetermined wavelengths the diffractive optical element has desired phase retardations, whereby generation of chromatic aberration is avoided.
The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood.


Low-grade systemic inflammation in overweight children: impact of physical fitness.
Obesity as well as low physical fitness and inactivity are associated with an increased incidence of cardiovascular risk factors and coronary artery disease (CAD). Increased inflammation has recently been addressed to play an important role for the relationship between obesity and CAD, as adipose tissue expresses and releases pro-inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha). As this relationship is less clear in childhood, we investigated 197 children aged 10-15 years assessing obesity, physical fitness, and a metabolic cardiovascular risk profile including markers of inflammation. Obese children had significantly higher concentrations of inflammatory parameters such as fibrinogen, ferritin, IL-6, and TNF-alpha than non-obese subjects (P<0.01). When dividing the children into groups regarding obesity (BMI < 22.5 kg/mz, BMI > or = 22.5 kglm2) and fitness (< 5 MET, > or = 5 MET), we found that obese, unfit children showed the highest systemic inflammation, whereas fit but obese individuals had as low levels as lean and fit children. These data reveal that even in childhood inflammatory parameters are elevated in obesity and that physical fitness counteracts this association.


Erionite is a natural zeolite that may occur as diagenetic product in sedimentary environment[@b1], as product of hydrothermal alteration[@b2], or in the vugs of altered basalts[@b3]. It belongs to the so-called ABC-6 family of zeolites[@b4], whose members are originating from the stacking along the *c*-axis of layers of six-membered rings made of (Si,Al)O~4~ tetrahedra, following an ABC scheme. Erionite is characterized by a 6-layer repetition, with hexagonal symmetry, space group *P*6~3~/*mmc*, unit cell *a* ≅ 1.315 nm, *c* ≅ 1.505 nm, and ideal formula K~2~(Na, Ca~0.5~)~7~\[Al~9~Si~27~O~72~\]·28H~2~O[@b5]. A large chemical variability characterizes this zeolite, with three different species identified according to the most abundant extra-framework cation: erionite-Na, erionite-K, and erionite-Ca[@b6][@b7]. The framework of erionite contains two double-6 rings (D6R), two cancrinite (ε) cages, and two erionite (23-hedron) cages per unit cell. Cancrinite and erionite cages host the extraframework cations (EF). The cancrinite cage contains a K^+^ ion located at the centre of the cavity, whereas several EF cation sites are placed along the *c* axis of the erionite cavity[@b8][@b9][@b10][@b11]. H~2~O molecules are arranged around the axis of the erionite cavity providing coordination to the EF cations.

Natural fibrous erionite has recently gained great concern because its environmental exposure has been linked to the outbreak of malignant mesothelioma (MM) epidemics in several villages of Central Anatolia, Turkey[@b12][@b13]. *In vivo* studies have unambiguously proven that fibrous erionite is by far more carcinogenic than chrysotile and crocidolite[@b14], and for this reason, it has been included by the International Agency for Research on Cancer (IARC) in the Group 1 Human-Carcinogen list (IARC 1987; 2011). Initially, environmental exposure to erionite has been hastily considered as locally circumscribed to Central Anatolia but in 1981, the first North American case of erionite-related lung disease was identified in Utah (USA)[@b15] and several others were subsequently reported[@b16]. Nowadays, the concern with the carcinogenic potential of erionite is of public interest in the USA and Europe and recent biological activity of erionite samples from different localities has been demonstrated to be similar[@b17]. Although the toxic potential of erionite is out of discussion, the mechanisms by which it induces cyto- and geno-toxic damage remain poorly understood. One of the reasons is the great chemical variability and molecular arrangement of natural fibrous erionites. A key factor contributing to its toxicity potential is deemed to be the presence of iron[@b18][@b19][@b20]. Iron in mineral fibres may be responsible for carcinogenic activity namely via ROS/RNS production during the phagocytosis induced inflammatory burst[@b21]. Specifically, active iron present at the surface of the fibres promotes the formation of reactive HO^•^ species by the surface Fenton reaction chain. Reactive HO^•^ are responsible for secondary genotoxicity via damage to proteins and DNA, cell injury/mutation, nucleotide coenzyme destruction, membrane damage, apoptosis, lipid peroxidation[@b22], and fibre encapsulation by collagen and iron-rich proteins[@b23]. Hence, the knowledge of the crystal chemistry of iron-bearing fibrous erionite is of absolute importance for understanding the mechanisms that prompt its bio-toxic action. But where is iron in erionite? The answer to this question is a hot topic, open to debate, with apparently disconnected, inconclusive and contradictory evidences reported in the specific literature. Theoretically, the following chemical environments are possible for iron in erionite: (1) Fe^2+^, and to a minor extent Fe^3+^, may virtually replace for Si^4+^ and Al^3+^ in the zeolite framework[@b24]; (2) Fe^3+^ and Fe^2+^ can be found in the extraframework cavities (micropores) as octahedral Fe(H~2~O)~6~ clusters; (3) Fe^3+^, and to a very minor extent Fe^2+^, can be associated with iron-rich impurities (both crystalline and amorphous oxides, hydroxides or sulphates) present as particles or nanoparticles coating the surface of the fibres.

Regarding model (1), the analysis of erionite-K from the Cappadocia region of Turkey obtained from TEM-EDS analysis published by Dogan[@b25] K~3.09~Na~0.26~Ca~1.57~Mg~0.55~\[Al~6.61~Si~28.70~Fe^3+^~0.60~O~72~\] apparently point to Fe^3+^ hosted in the zeolite framework but no justification to that assignment is given. The EPMA analysis of several fibrous erionite-K (and offretite) samples from the Killdeer Mountains, Dunn County (North Dakota, USA) displays an extremely variable iron content (003--1.99 wt% Fe~2~O~3~) that was also arbitrarily assigned as Fe^3+^ hosted in the zeolite framework[@b26].

Regarding model (2), natural samples with iron hosted in the erionite micropores have never been reported to date. Oppositely, Fe^2+^-exchanged erionites have been obtained in laboratory[@b27][@b28]. According to Ballirano *et al*.[@b28], Fe^2+^ is fixed in the erionite cage and is six-fold coordinated to H~2~O molecules. The occurrence of Fe^2+^ within the erionite cage causes a gradual migration of the other EF cations and in addition, induces a small rearrangement of the H~2~O molecules.

As far as model (3) is concerned, in erionite-K from Rome (Oregon, USA), 95% of iron was attributed to Fe^3+^-bearing, super-paramagnetic, oxide-like nanoparticles with dimensions between 1 and 9 nm, and the remaining 5% was attributed to hematite particles with size ≥10 nm, both located at the crystal surface[@b10]. Later, Matassa *et al*.[@b29] discovered that the same erionite-K from Rome actually contains aggregates of nontronite, an iron-bearing smectite of ideal formula (Ca~0.5~, Na)~0.33~Fe^3+^~2~(Si~3.67~Al~0.33~)O~10~(OH)~2~·nH~2~O. Successive EDX analysis of the fibres leached with simulated lung fluids (SLF) indicated the absence of iron due to the removal of nontronite from their surface produced by the leaching process, confirming the absence of iron in the structure of erionite. The same sample has been selected for a BSE-EDS analysis combined with micro-Raman spectroscopy and iron has been identified as component of iron-bearing microcrystals of hematite (α-Fe~2~O~3~), goethite (α-FeOOH), and jarosite KFe~3~(SO~4~)~2~(OH)~6~ nucleated at the surface of the fibres[@b30]. Iron was not hosted in the crystal structure, although the detection limits of the applied methods do not permit to unequivocally rule out this possibility. The same authors found that iron in fibrous erionite-K from Karlik (Cappadocia, Turkey) was as well present as iron-bearing sub-micrometric crystals of hematite and goethite coating the surface of the fibres[@b30], and not in the crystal structure.

Minor amounts of iron (Fe~2~O~3~ \< 0.13 wt%) were determined but not interpreted for fibrous erionite-K from Lander County (Nevada, USA) and Karain (Turkey)[@b31]. Iron has also been qualitatively detected but not interpreted in a fibrous (presumably) erionite-Na found in the lung tissue of a North American patient who was raised on a farm in the Mexican Volcanic Belt region and died of epithelial pleural MM[@b32].

This work is focused on the full characterization of a representative sample of fibrous erionite-Na from Jersey (Nevada, USA) which contains iron from the micro- to the atomic scale. The detailed study of the crystal structure, with special attention to iron is an attempt to put the pieces of the puzzle together, draw a general model of occurrence of iron in erionite and revise its toxicity model in respect to iron chemistry. Preliminary information on the chemical environment of iron in the sample has been attained from Mössbauer and X-ray absorption spectroscopy experiments[@b33].

Results
=======

[Table 1](#t1){ref-type="table"} reports the interatomic distances of fibrous erionite-Na from Jersey calculated from the Rietveld refinement using the synchrotron data at the absorption K-edge of iron. Identical results were obtained using the data away from the absorption edge. The major result is that no evidence was found to support the presence of iron in both the framework or extraframework cavities, despite several attempts using different refinement strategies and chemistry constraints (site population constrained to the iron content from the chemical analysis).

[Figure 1](#f1){ref-type="fig"} portrays an example of high resolution TEM image of the erionite sample with single fibres characterized by stacking disorder along the *c* axis and the relative diffraction pattern from an area of high cristallinity. As already evidenced in the preliminary TEM study[@b33], rare iron-rich nanoparticles were originally discovered at the surface of the erionite fibres. [Figure 2](#f2){ref-type="fig"} displays one of these particles with the relative EDS analysis revealing that such clusters are enriched in iron with respect to the bulk. Other nanoparticles of smaller diameter (around 10 nm) were also observed in the same sample during the TEM sessions. [Figure 3](#f3){ref-type="fig"} are FEG/SEM images and relative EDS analysis on the erionite sample revealing the presence of micrometric particles at the surface of the erionite fibres. From the EDS analysis on the brighter clusters, it is clear that they are enriched in iron with respect to the fibre bulk. [Figure 4](#f4){ref-type="fig"} is another beautiful TEM picture witnessing the presence of micro- to nano-metric flakes associated to the erionite fibres. The size of each single particle is certainly nanometric ([Fig. 4a,b](#f4){ref-type="fig"}). The analysis of the electron diffraction rings produced by such aggregates ([Fig. 4c](#f4){ref-type="fig"}) permitted to identify the impurity as nontronite, with the rings at a *d*-spacing of 0.454 (*020*), 0.321 (*003*), 0.259 (*200* and ), 0.171 (), 0.152 (), 0.131 (. . *027*, and *136*) nm. The first ring corresponding to the *001* is hidden by the direct beam. Once again, these flakes are enriched in iron with respect to the bulk of the fibres ([Fig. 4d](#f4){ref-type="fig"}). The EDS spectra also revealed a concentration of Mg in correspondence with the clay flakes. [Figure 5a](#f5){ref-type="fig"} is the full XPS spectrum of the erionite sample, giving indication on the chemical nature of surface iron in erionite. To identify the fractions of different oxidation states of iron, the peak deconvolution of the region with the Fe 2p~3/2~ has been made ([Fig. 5b](#f5){ref-type="fig"}) following the same procedure used in Fantauzzi *et al*.[@b34]. The peak fit (R^2^ = 0.99909) permitted to identify and quantify both the Fe^3+^ (30%) and Fe^3+^OOH (70%) contributions.

Discussion
==========

The nature of iron in fibrous erionite
--------------------------------------

The XAFS and Mössbauer spectroscopy of fibrous erionite-Na from Jersey, discussed in detail in Pollastri *et al*.[@b33], give evidence of the exclusive presence of Fe^3+^ hosted in an octahedral (6-fold) environment. In particular, the EXAFS data identify a first shell of six oxygen atoms at a mean distance of 0.2011 nm, very close to the theoretical distance Fe^3+^-O (0.2015 nm) for octahedral iron[@b33]. The Mössbauer data also show the absence of magnetic sextets typical of iron oxide, indicating that the iron-bearing phase must have a dimension under the resolution limit of the measurement at RT, namely \<18 nm[@b35].

The outcome of the structure refinement confirms the absence of structural iron in natural fibrous erionite ruling out both Fe^2+^/Fe^3+^ in place of Si^4+^/Al^3+^ in the zeolite framework and Fe^3+^/Fe^2+^ in the extraframework cavities (micropores) as octahedral Fe(H~2~O)~n~ clusters.

Concerning the framework, the two independent tetrahedral sites T1 and T2 (building respectively, the D6R and the S6R) are characterized by disordered Si/Al distribution. In fact, the \<T1-O\> − \<T2-O\> is −0.0044 nm, indicating the preferential partition of Al for T2, in agreement with the literature data[@b8][@b9][@b10]. As far as the extraframework cations are concerned, K atoms are found at the centre of the cancrinite cage ([Fig. 6](#f6){ref-type="fig"})[@b9][@b10][@b36]. K is bonded to 12 framework oxygen atoms (6 O2 and 6 O3) at a mean bond distance of 0.317 nm, and the K site is fully occupied (see [Table 1](#t1){ref-type="table"}), in agreement with Ballirano *et al*.[@b10]. A minor fraction of K ions are found in the erionite cage, in correspondence with the crystallographic site labelled Ca4 (K2 in Ballirano *et al*.[@b10]). The coordination of K in that site is also 12-fold with 6 framework oxygen atoms (4 O1 and 2 O4) and 6 H~2~O molecules (4 O~w8~ and 2 O~w12c~) at a mean bond distance of 0.3192 nm. The erionite cage hosts a number of Na and Ca ions in a disordered fashion ([Fig. 6](#f6){ref-type="fig"}). Site Ca1 which hosts minor Ca ions is close to the centre of the single 6-membered ring shared by two adjacent erionite cages, forming the base of the cavity. Ca ions are 12-fold coordinated by H~2~O molecules only (O~w8~, O~w10~, O~w12b~, and O~w12c~) at a mean bond distance of 0.244 nm. Although Ca1 is invariably coordinated to H~2~O molecules only, a different coordination number is reported for erionite-Ca[@b9] (3) and erionite-K^10^ (11 if distances \<0.3 nm considered). Na ions are distributed over three distinct sites (Ca2, Ca3, and Ca4b). Ca2 is close to the centre of the upper half of the cavity where Na is in 6-fold coordination with H~2~O molecules (3 O~w8~ and 3 O~w12b~) at a mean bond distance of 0.223 nm. The same coordination number was found for erionite-K^10^ (6) whereas a different number is reported for erionite-Ca[@b9] (6--12). The latter also includes a connection with the framework oxygen atom O5 at 0.2922 nm. Ca3 is shifted along the 3-fold axis in the erionite cage, close to the 6-membered ring. Na in Ca3 site has a 6-fold coordination with H~2~O molecules (3 O~w9~ and 3 O~w12c~) at a mean bond distance of 0.234 nm. The coordination number of Ca3 is larger for erionite-Ca (9--12)[@b8][@b9]. Na is also hosted in the new site Ca4b, shifted with respect to the main 3-fold axis with Na that again displays a 6-fold coordination with H~2~O molecules (2 O~w8~, 2 O~w11~, O~w12b~ and O~w12c~) at a mean bond distance of 0.2757 nm. Site Ca3 and Ca4b are not reported for erionite-K^10^.

Attempts were made with the aim to locate Mg ions in the structure but they all invariably failed, indicating that minor Mg from the chemical analysis belongs to impurities of clay phases (see below) other than to the erionite structure.

The experimental evidences in our hands confirm that the investigated erionite fibres from Jersey do not contain structural Fe^3+^ and point to Fe^3+^ associated to iron-rich impurities, corroborating model (3) (see Introduction).

The fact that iron is not found in the erionite structure of natural samples has also a sound petro-genetic basis. Erionite is a sedimentary zeolite likely formed in open hydrologic systems or hydrothermal environment during the so-called *zeolitization* process[@b37][@b38]. During the process, iron eventually present as Fe^2+^ in the host tuffs, is leached, oxidized and precipitated later as secondary iron-bearing phases like iron hydroxides. Even the hydrothermal synthesis in laboratory aimed at reproducing the natural system evidenced that the majority of Fe^3+^ ions of the zeolitized samples is not included in the zeolitic structures as isomorphous substituent or exchanged cation, but belongs to ancillary phases[@b39].

The fibrous erionite sample is kind of heterogeneous as it contains iron-bearing impurities of different nature. We have found amorphous iron-oxide/hydroxide nanoparticles with diameter around 10 nm or greater (around 50 nm: [Fig. 2](#f2){ref-type="fig"}). Such nanoparticles resemble those observed by Ballirano *et al*.[@b10] in erionite-K from Rome (Oregon, USA) where most of iron was attributed to Fe^3+^-bearing, super-paramagnetic, oxide-like nanoparticles of size between 1 and 9 nm. The FEG/SEM study also revealed the presence of micrometric particles, possibly aggregates of nano/micro-particles of iron oxides/hydroxides, at the surface of the erionite fibres ([Fig. 3](#f3){ref-type="fig"}). The same micro-aggregates have been reported for erionite-K from Rome[@b10][@b30], and for erionite-K from Karlik (Cappadocia, Turkey)[@b30]. According to Croce *et al*.[@b30], erionite-K from Rome contains iron-bearing microcrystals of hematite (α-Fe~2~O~3~), goethite (α-FeOOH), and jarosite KFe~3~(SO~4~)~2~(OH)~6~ at the surface of the fibres, whereas the erionite-K from Karlik shows iron-bearing sub-micrometric crystals of hematite and goethite at the surface of the fibres. High resolution TEM imaging also revealed the presence of micro- to nano-metric flakes enriched in iron with respect to the bulk of the fibres ([Fig. 4](#f4){ref-type="fig"}). Such flakes have been identified as nontronite. Nontronite also explains the minor amount of Mg detected by the chemical analysis of the sample. The presence of nontronite as clay impurity in fibrous erionite samples has been already reported[@b29]. Hence, with the results of our study we have verified that the very same erionite sample may contain different iron-bearing impurities, explaining why different authors see impurities of different kind in natural fibrous erionite.

The coordination environments of iron of the impurities is also compatible with the results from the XAFS and Mössbauer study[@b33]. Goethite, hematite and nontronite all have Fe^3+^ in octahedral environment. Although uncommon, nontronite may contain very minor tetrahedral Fe^3+^ if the Fe~2~O~3~ content is \>37%[@b40]. The mean calculated Fe^3+^-O bond distance in goethite[@b41], hematite[@b42] and nontronite[@b43] are 0.2013, 0.2029, and 0.2013 nm, respectively. Such values are in agreement with the EXAFS data showing a first shell of six oxygen atoms at a mean distance of 0.2011 nm.

Is the toxicity of fibrous erionite related to iron?
----------------------------------------------------

Fibrous erionite is considered more potent than chrysotile in causing MM[@b44] and the understanding of toxicity mechanisms of this peculiar mineral fibre is still an open issue. Many authors believe that iron plays a key role in determining the toxicity of this fibre as erionite toxicity has been partly ascribed to ion-exchanged and/or surface-deposited Fe participating in Fenton chemistry[@b10][@b45][@b46]. Along the same research line, it was found that erionite from Rome, Oregon and Pine Valley, NV (adjacent to Jersey, NV) show quite different effects in animal studies. The sample from Rome is iron-rich whereas the sample from Pine Valley has very low iron content. The results indeed show that Rome erionite with Fe in some form, is more potent than Fe-poor erionite[@b47]. This result has important consequences for other animal studies because most laboratory experiments have used Rome erionite and may be the main basis for the general conclusion that erionite is more carcinogenic than asbestos minerals.

The results of our study clearly demonstrate that iron is not part of the erionite crystal structure but is associated to impurities, mostly concentrated at the surface of the fibres. If iron is not part of the structure, its role should be carefully reconsidered and a specific model of bioavailability should be developed to understand the carcinogenicity of erionite fibres. In fact, there is a sharp distinction between the iron content of a fibre and the iron content of a particle like an iron oxide, present as impurity. Toxicity due to release of HO^•^ is related to the content of active surface structural iron of a fibre as the latter may prompt the activation and release of H~2~O~2~ (or radical species O~2~^−^ or free oxygen) during macrophage frustrated phagocytosis. The proof that structural iron of a fibre is a key factor is found in Gazzano *et al*.[@b48] who reported that synthetic stoichiometric chrysotile nanofibers, devoid of iron did not exert genotoxic and cytotoxic effects. On the contrary, the same nanofibers, loaded with 0.57 wt% and 0.94 wt% iron, induced DNA strand breaks, lipoperoxidation, inhibition of redox metabolism and alterations of cell integrity, similarly to natural chrysotile. On the other hand, the iron in a sub-spherical particle or nanoparticle will not be active (and hence toxic) as it is successfully phagocytized by macrophages, with no H~2~O~2~-mediated release of HO^•^. If we share this view, iron should not be involved in the toxicity mechanism of erionite fibres as the low iron content is actually *alien* Fe^3+^, in the form of Fe^3+^-rich oxide nanoparticles. If *alien* iron in fibrous erionite is irrelevant for its potential toxicity, other factors should be invoked. One of these is certainly the high biopersistence of this fibre species in both extracellular and intracellular environment. Another factor that has been recently disclosed is that fibrous erionite may contain appreciable amounts of toxic elements such as As, Be and Pb. Since there is convincing evidence of a relationship between lung cancer mortality and cumulative As, Be, and Pb exposure, the toxicity of this fibre species may also be related to the synergetic effect of these contaminants[@b49].

There is an alternative perspective to the proposed model of *alien* iron in fibrous erionite: although micro-particles of iron oxides (namely goethite and hematite) are stable in acidic environment[@b50][@b51], iron rich nano-particles and especially nontronite are not[@b29]. Hence, the latter can be dissolved during alveolar macrophage phagocytosis when the fibres are engulfed in the lysosome sacks with acidic environment (pH = 4--4.5) ([Fig. 7a](#f7){ref-type="fig"}). The dissolution of such phases present at the surface of the erionite fibres should leave a residue of iron atoms at specific sites anchored to the surface windows of the zeolite channels ([Fig. 7b](#f7){ref-type="fig"}). One of these sites may be at the windows of the 6-membered rings anchored to 4 oxygen atoms of the framework (specifically O2 and O3) and 2 H~2~O molecules to gain an octahedral coordination ([Fig. 7c](#f7){ref-type="fig"}). With reference to the erionite unit cell, the position of that iron site should be x/*a* = 0.1116; y/*b* = 0.0; z/*c* = 3/4. The surface sites for iron may become active as low nuclearity groups. Although the site described here hosts Fe^3+^, active sites have already been reported for erionite as isolated (FeO)^2+^ structures as preferred candidate active sites \[(H~2~O)~5~FeO\]^2+^ due to their low nuclearity[@b52]. Instead, paired Fe^2+^ − Fe^2+^ active species or Fe~x~O~y~ clusters eventually entrapped into the zeolite framework cavities are considered less active.

A final speculative remark concerns the possibility that in open environment erionite fibres undergo reduction of surface iron by microbial species. This is a common biochemical process observed for many iron-bearing minerals[@b53]. The production of surface Fe^2+^ enhances the toxicity of the fibres as it directly promotes the formation of reactive HO^•^ species by the well known Fenton reaction sequence.

Methods
=======

Sample selection and characterization
-------------------------------------

A natural fibrous erionite-Na from Jersey, Nevada (USA) has been selected for this study. The quantitative chemical composition was determined by Electron Micro Probe Analysis (EMPA) using a JEOL 8200 Super Probe instrument with W hairpin type filament and minimum accelerating voltage of 30 kV. For the determination of the water content, thermogravimetric and differential scanning calorimetry (TG/DSC) analysis were performed using a Netzsch STA 449 C Jupiter and published elsewhere[@b49]. The final crystal chemical formula was calculated, after renormalization of the chemical analysis with a H~2~O content of 18.5 wt%, which corresponds to about 30 atoms per formula unit (*apfu*), on the basis of 36 (Si + Al) *apfu*.

The calculated formula is: Fe^3+^~0.29~(Na~5.35~K~2.19~Ca~0.15~Mg~0.11~Ti~0.05~)~7.85~\[Si~28.01~Al~7.90~\]~35.91~O~72~·28.13H~2~O. Iron has been intentionally excluded from both the group of framework and extraframework cations because of its uncertain location. The specimen contains less than 1 wt% of clinoptilolite. Other impurities are below the detection limit of X-ray diffraction. The detailed electron microscopy study of the fibres was performed using a FEG/SEM FEI Quanta Nova NanoSEM 450 instrument, a JEM 2010 JEOL TEM a and a FEI Tecnai STEM. As anticipated, the chemical environment of iron was previously determined using Mössbauer and X-ray absorption spectroscopy (XANES and EXAFS)[@b33]. XPS spectra were acquired by a V.G. ESCALAB MKII using a Mg anode (Kα radiation line at 1253.6 eV unmonochromatised) as X-ray source, operating at a voltage of 10 kV and a power of 240 W. Spectra were acquired at pass energy of 20 eV and step channel of 0.1 eV.

Synchrotron powder diffraction and Rietveld refinement strategy
---------------------------------------------------------------

Synchrotron X-ray powder diffraction (XRPD) patterns were collected at the MCX beamline at the synchrotron facility of ELETTRA (Trieste, Italy). Data were collected with an analyzer crystal detector in Debye-Scherrer mode, at two different energies: close to the absorption K-edge of iron (≈7 keV, λ 0.17428 nm) and far away from the absorption edge of iron (≈10 keV, λ 0.12408 nm). In this way, potential anomalous dispersion effects due to iron could be evaluated because at the absorption energy anomalous intensities from the diffracting planes of the crystalline phases (both erionite or impurities) containing iron arise. Such effect can be modelled within the Rietveld refinement and permits to eventually locate iron in the crystal structure. Structure refinements were accomplished using the GSAS package[@b54] and its graphical interface EXPGUI[@b55]. The starting structure model (space group *P*6~3~/*mmc*) was taken from Gualtieri *et al*.[@b9]. The structure factors were calculated using the formal scattering factors for neutral atoms. The background profile, due to the scattering of the capillary, was successfully fitted with a Chebyshev polynomial function with 28 coefficients. The diffraction peak profiles were modelled using a pseudo-Voigt function with a θ-independent Gaussian and two Lorentzian coefficients. The unit-cell parameters and phase fraction were refined together with the atomic coordinates, the atomic site occupancies for extraframework positions, and the isotropic atomic displacement parameters. Soft constraints on tetrahedral bond lengths were imposed and used as additional observations in the earlier stages of the refinement procedure. The weight of the constraints was progressively reduced to zero in the later stages. Difference-Fourier maps of the electron density function were calculated from the refined model and were useful for the location of residual electron density, corresponding to extraframework cations or H~2~O molecules. The structure refinement using the data collected at the iron absorption edge were conducted in the attempt to locate structural iron in the zeolite structure. The population of the crystallographic sites which were supposed to host iron was refined using anomalous scattering factors f′ (−7.98) and f″ (1.862) for Fe^3+^ at 7112 eV.

As an example, the graphical output of the Rietveld refinement using the data collected at the iron absorption edge is shown in [Supplementary Fig. 1](#S1){ref-type="supplementary-material"}. Miscellaneous statistics of the refinements and calculated structure parameters are reported in [Supplementary Table 1](#S1){ref-type="supplementary-material"}. Full structural data of erionite has been deposited under the form of CIF file.

Additional Information
======================

**How to cite this article**: Gualtieri, A. F. *et al*. Where is iron in erionite? A multidisciplinary study on fibrous erionite-Na from Jersey (Nevada, USA). *Sci. Rep.* **6**, 37981; doi: 10.1038/srep37981 (2016).

**Publisher\'s note:** Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Material {#S1}
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###### Supplementary Information

This research was conducted under the project "*Sviluppo di un modello generale di interazioni tra fibre minerali e cellule biologiche*", a part of the comprehensive granted long term Italian Research Project of National Interest (PRIN 2011) "*Interazione fra minerali e biosfera: conseguenze per l'ambiente e la salute umana*". Synchrotron XRPD patterns were collected at the MCX beamline (ELETTRA, Trieste, Italy) during the experimental shift 20150053 (July 2015). We are indebted with Prof. N. Perchiazzi and M. Lezzerini for the support during the synchrotron data collections. Dr. Th. D. Makris (ENEA, Technical Unit on Material Technologies, Casaccia Research Centre, Rome, Italy) is kindly acknowledged for the data collection of the XPS spectra. Dott. M. Zapparoli (Centro Interdipartimentale Grandi Strumenti -- C.I.G.S., The University of Modena and Reggio Emilia, Modena, Italy) is warmly acknowledged for the support during the TEM sessions in Modena.

**Author Contributions** A.F.G. conceived the project and conducted the synchrotron XRPD experiment, analysed the results, wrote and revised the manuscript; N.B.G. and S.P. performed and coordinated the electron microscopy study; S.P. also performed the preliminary characterization. K.P. and F.L. performed part of the TEM analyses. All authors revised and contributed to the discussion.

![High resolution TEM image of fibrous erionite-Na.\
TEM imaging of fibres of erionite-Na showing signs of stacking disorder along c (**a**) and the relative SAED pattern from an area of high cristallinity with zone axis \[\] (**b**). Diffraction spots 000 *l* with *l* = 2n + 1 in the \[000 *l*\]\* rows apparently break the conditions imposed by the systematic absences for that space group *P*6~3~/*mmc*, but this is a physical effect due to multiple diffraction effects from a thick section of the specimen under the beam.](srep37981-f1){#f1}

![Nanoparticles at the surface of the erionite-Na fibres.\
High-resolution TEM image of erionite sample with spherical iron-bearing nanoparticles at the surface of the fibres. The EDS spectra evidence that the nanoparticles are enriched in iron with respect to the fibre bulk.](srep37981-f2){#f2}

![FEG/SEM images and EDS of the erionite-Na fibres.\
Submicronic clusters of iron-rich particles at the surface of the erionite-Na fibres captured during a FEG/SEM session and relative EDS witnessing the enrichment in iron (**a** and **b**) with respect to the bulk of the fibre (**c**).](srep37981-f3){#f3}

![TEM images of nontronite flakes associated to the erionite-Na fibres.\
TEM images and relative EDS spectra showing the presence of micro- to nano-metric flakes of nontronite close to the erionite fibres. The *d*-spacings of the rings of the electron diffraction pattern are compatible with the major diffraction maxima of nontronite.](srep37981-f4){#f4}

![XPS spectra collected on fibrous erionite.\
The full XPS spectra collected on fibrous erionite (**a**) and the the Fe 2p~3/2~ spectra curve fit (**b**) with the experimental curve (red), the calculated curve (blue), the single contributions (green and orange), and the difference curve (light blue on the top).](srep37981-f5){#f5}

![A plot of the calculated structure of fibrous erionite from Jersey (Nevada, USA).\
A plot of the calculated structure of fibrous erionite from Jersey (Nevada, USA) in the *a*-*b* plane with the position of the extraframework cations. Legend: green balls = Na; light blue balls = Ca; cobalt blue balls = K; white balls =  H~2~O molecules.](srep37981-f6){#f6}

![Location of possible active iron sites at the surface of erionite fibres.\
If the iron-rich nanoparticles at the surface of the erionite fibres (**a**) are dissolved during alveolar macrophage phagocytosis at pH = 4--4.5, the residue of the dissolution at the surface should be iron atoms at specific surface sites (**b**) anchored to the windows of the zeolite channels. One of these sites may be found at the windows of the 6-membered rings anchored to 4 oxygen atoms of the framework and 2 water molecules to form a distorted octahedral coordination (**c**).](srep37981-f7){#f7}

###### Calculated distances and angles of fibrous erionite from Jersey (Nevada, USA).

  Framework
  -----------------------------------
  T1-O1 0.1613(1) nm
  T1-O2 0.1612(1) nm
  T1-O3 0.1617(1) nm
  T1-O4 0.1623(1) nm
  mean 0.1616 nm
  O1-T1-O2 111.03(8)°
  O1-T1-O3 108.54(7)°
  O1-T1-O4 106.94(6)°
  O2-T1-O3 108.67(8)°
  O2-T1-O4 110.69(7)°
  O3-T1-O4 110.95(8)°
  mean 109.47°
  T2-O1 0.1675(1) nm
  T2-O1 0.1675(1) nm
  T2-O5 0.1641(1) nm
  T2-O6 0.1651(1) nm
  mean 0.1660
  O1-T2-O1 108.52(7)°
  O1-T2-O5 114.50(7)°
  O1-T2-O6 105.92(8)°
  O1-T2-O5 114.50(4)°
  O1-T2-O6 105.92(6)°
  O5-T2-O6 106.76(7)°
  mean 109.35°
  **Extraframework**
  [Ca1]{.ul} =  [atom type Ca]{.ul}
  Ca1-Ow8 0.227(1) nm × 3
  Ca1-Ow10 0.210(1) nm × 3
  Ca1-Ow12b 0.258(1) nm × 3
  Ca1-Ow12c 0.282(1) nm × 3
  mean 0.244 nm
  Ca1-Ow9 0.185090(1) nm × 3
  Ca1-Ow11 0.164082(1) nm × 3
  [Ca2]{.ul} =  [atom type Na]{.ul}
  Ca2-Ow8 0.227(2) nm × 3
  Ca2-Ow12b 0.219(1) nm × 3
  mean 0.223 nm
  [Ca3]{.ul} = [atom type Na]{.ul}
  Ca3-Ow9 0.207(2) nm × 3
  Ca3-Ow12c 0.2604(9) nm × 3
  mean 0.234 nm
  Ca3-Ow7 0.275(1) nm × 3
  Ca3-Ow8 0.288(1) nm × 3
  Ca3-Ow10 0.277(1) nm × 3
  Ca3-Ca1 0.081(1) nm
  Ca3-Ow10 0.163(2) nm × 3
  Ca3-Ow11 0.179(2) nm × 3
  [Ca4]{.ul} = [atom type K]{.ul}
  Ca4-O1 0.326(1) nm × 4
  Ca4-O4 0.312(2) nm × 2
  Ca4-w8 0.332(2) nm × 4
  Ca4-w12c 0.287(1) nm × 2
  mean 0.3192 nm
  Ca4-w9 0.2379(9) nm × 2
  Ca4-w12b 0.204(2) nm × 2
  [Ca4b]{.ul} = [atom type Na]{.ul}
  Ca4b-Ow8 0.2598(9) nm × 2
  Ca4b-Ow11 0.2979(9) nm × 2
  Ca4b-Ow12b 0.285(2) nm
  Ca4b-Ow12c 0.254(1) nm
  Mean 0.2757 nm
  Ca4b-Ca4b 0.167(9 nm
  Ca4b-K2 0.084(1) nm
  Ca4b-Ow9 0.169(1) nm
  Ca4b-Ow12b 0.125(1) nm
  [K]{.ul} = [atom type K]{.ul}
  K-O2 0.299(1) nm × 6
  K-O3 0.335(2) nm × 6
  mean 0.317 nm
  **Water molecules**
  Ow8-Ow11 0.163(1) nm
  Ow8-Ow12b 0.178(1) nm
  Ow8-Ow12b 0.178(1) nm
  Ow9-Ow10 0.165(3) nm
  Ow9-Ow11 0.176(1) nm × 2
  Ow9-Ow12b 0.171(1) nm
  Ow9-Ow12c 0.146(2) nm
  Ow10-Ow10 0.167(1) nm
  Ow10-Ow11 0.209(2) nm × 2
  Ow10-Ow12c 0.115(1) nm