**3.2. Pulsed UV laser at 248 nm**

**Figure 7** illustrates the microscopic image of the ablated CR39 craters spot size. The elimina‐ tion of material and creation of the crater due to the ablation process are presented by the dark spot on the surface of the CR39. Partial transparent curves can be seen surrounding the edge of the craters. This could possibly be caused by the heat affected zone (HAZ), which occurs during the process of laser ablation. Heat affected zones (HAZ) are the outcome of materials that are molten due to heat transfer from the crater and then rapidly cooled. The short pulse width of the excimer laser nevertheless reduces the heat transfer from the ablated crater. This phenomenon is thought to be caused by the photothermal effect in which the laser energy absorption by the material is converted into heat energy, which in turn leads to the localized modification of its structure.

**Figure 8** alternatively illustrates the average etch depth per pulse as a function of fluence F for CR39 ablated at 248 nm based on 150, 180, and 210 pulses. A linear fit of the form *d* = *k*‐1 *ln F/F*T provides an ablation threshold of 6–7 mJ cm‐2 . This value is marginally lower than that reported using 157 nm laser which gives *F*T as 11 mJ cm‐2 [10].

### **3.3. Continuous UV laser at 244 nm**

**Figure 6.** Fringes seen at the region of the bottom of the cones on CR39 (a) 100 pulses at ~60 mJ cm‐2 and (b) 100 pulses

366 Applications of Laser Ablation - Thin Film Deposition, Nanomaterial Synthesis and Surface Modification

at ~182 mJ cm‐2.

This section describes the use of this particular polymer as a waveguide where here we utilized a CR39 polymer sheet with a thickness of 0.5 mm and a refractive index as 1.486. Tunable laser

**Figure 7.** (a) Optical microscope imaging of the surface craters at CR39, (b) FESEM image of the crater, and (c) higher magnification of the ablated surface.

**Figure 8.** Plot of etch depth/pulse against log fluence at 150, 180, and 210 pulses on CR39.

**Figure 9.** Optical waveguide channel fabricated on CR39.

source at 1550 nm (Sairon Technology SPA‐4000 Prism Coupler) was used as a substrate for the polymer waveguide. SU‐8 polymer was spin coated on the CR39 sheet and patterned using photolithography technique, formed a core of the channel waveguide structure. The height of the channel waveguide measured using optical microscopy was recorded as 5.0 ± 0.1 µm and width range between 10 and 15 µm. **Figure 9** shows the fabrication of the waveguide using photolithography technique.

**Figure 10** shows the mode field diameter (MFD) and refractive index contrast of CR39 wave‐ guide against the laser fluence. The refractive index change is seen to be more significant with the increase in fluence. Higher laser fluence will lead to a higher change of the refrac‐ tive index, which likens to the reaction of other optical materials including silica glass to laser ablation. Extrapolation of the results in **Figure 10** also forecasts that the refractive index can be increased by the irradiation of CR39 with higher fluence. This increase, however, was observed to be limited as an upper fluence limit (5 KJ/cm2 ) exists. When the laser fluence is above this limit, ablation will occur and subsequently UV irradiation of the CR39 will lead to the elimination of materials from its surface, similar to the outcome that occurs in Section 3.

The microscope image of the modification and ablation of CR39 is illustrated in **Figure 11**. As a result of refractive index modification, a partially transparent line can be seen in **Figure 11a**, whereas **Figure 11b** shows a darker line that indicates the removal of material and formation of craters due to ablation. The inset in **Figure 11b** further shows a cross‐sectional view of the ablated sample. It is easier to detect the ablation effect from cross‐sectional images in which a part of CR39 is removed. Subject to the laser fluence being applied, the removed area depth can be up to several microns.

**Figure 8.** Plot of etch depth/pulse against log fluence at 150, 180, and 210 pulses on CR39.

368 Applications of Laser Ablation - Thin Film Deposition, Nanomaterial Synthesis and Surface Modification

**Figure 9.** Optical waveguide channel fabricated on CR39.

**Figure 10.** MFD and index contrast of CR39 waveguides versus laser fluence at 30 mW laser power.

**Figure 11.** Microscope images of (a) internal modification, (b) ablation of CR39, and (inset) cross‐sectional view of ablated CR39.


**2. Short characteristic of dermatophytes**

There are many species of dermatophytes causing mycoses, so it is very important to assay them properly through mycological examination. Correct identification of the pathogen responsible for disease allows choosing a right treatment for patient.

Natural reservoir of dermatophytes is soil and keratin contained in soil is used as main nutrient for these fungi. However, evolutionary progress adapted these microorganisms to a various environments, so they generated ability to metabolize keratin derived not only from soil (Dworacka-Kaszak, 2004).

For that reason dermatophytes, with regard to their habitat, may be divided into antropophilic, zoophilic and geofilic species. For antrophophilic dermatophytes natural reservoir and carrier is human, zoophilic dermatophytes grow on domestic and stock animals and geophilic dermatophytes are found in soils (Adamski & Batura-Gabryel, 2007).

In laboratory practice dermatophyte fungi belonging to three genera (*Trichophyton*, *Microsporum*, *Epidermophyton*), are known. *Trichophyton* and *Microsporum* genera are the most numerous and diverse, there are over 40 species belonging to these two taxonomic groups. *Epidermophyton* genus has only one representative – *Epidermophyton floccosum* species.

The genera *Trichophyton* is numerous and diverse, for example, in the Lower Silesia region, in years 2003 – 2007, these fungi were isolated in 92% of all cultures (Jankowska-Konsur et al., 2011).

Epidemiology of Dermatomycoses in Poland over the Past Decades 33

 *Microsporum gypseum* – geophilic species, ubiquitous, isolated from soils worldwide. Most exposed to infections are people, who cultivate the soil (farmers, gardeners), percentage of males prevails over females. Sometimes infection could be transmitted from animals . In human it causes infections of the scalp (*tinea capitis*) and glabrous skin

 *Microsporum nanuum* – zoophilic species, isolated also from soil. It causes infections among breeding cattle, mostly in pigs. In human it causes infections of the glabrous skin (*tinea corporis*) and the scalp (*tinea capitis*) proceeding with or without severe

 *Microsporum persicolor* – zoophilic species, cosmopolitan. In human it causes infections of the scalp (*tinea capitis*), glabrous skin (*tinea corporis*) and feet (t*inea pedis*). Infections

The genera *Epidermophyton* has only one representative, quite often isolated form lesions:

 *Epidemophyton floccosum* – antropophilic species, cosmopolitan. In human it causes mostly infections of the groin (*tinea cruris*), rarely of glabrous skin (*tinea corporis*), feet

Dermatophytes are keratinophilic fungi, which parasitize on corneous structures, such as stratum corneum, hair or nails (Kobierzycka et al., 2005). Dermatophyte species are equipped with numerous enzymes, enabling them to survive on the skin and its appendages, because they have a proteolytic, keratinolytic and lipolytic activity. Furthermore the skin environment is conducive to dermatophytes because the corneal layer lacks blood vessels making it difficult to contact with immunologically competent cells and activate the defense mechanisms. On the surface of the epidermis are proteins, carbohydrates and micronutrients (including iron ions), which may provide substrates for the metabolism of fungi and help them to survive. Of great importance may also be some specific anatomic regions of the skin, greatly facilitating the colonization by fungi. Scalp hair can therefore arrest arthrospores spreaded by air. Similarly, spores are arrested in the hyponychium under or in the interdigital spaces, or in the folds of the skin where additionally oclusion helps them to develop (Dworacka-Kaszak, 2004). The spores are particularly resistant to environmental conditions, such as variable temperature and drying (Hryncewicz-Gwozdz et al., 2005; Kobierzycka et al., 2005). It is known that they can survive outside the host organism and colonize the skin and its appendages under favorable conditions, for example, in warm and humid environment, with increased amounts of CO2, which prevails in the poorly sheered shoes, it can lead to growth of the fungi and invasion of

To narrowly understand epidemiology of dermatomycoses, methods of pathogen

Infection with antropophilic dermatophytes may happen through direct contact with infected person, moreover spores of dermatophyte fungi can survive on skin and its

The sources of dermatophyte fungi infection are: human, animals and soil.

was isolated from fur of guinea pigs and rarely, from dog`s fur.

proceed with significant inflammatory reaction.

(*tinea pedis*) and very rarely of toenais (*onychomycosis)*.

**2.1 Methods of pathogen transmission – a short description**

(*tinea corporis*).

inflammation.

the skin structures.

transmission, are described below.

caused by *Microsporum audouinii* also were described. Although it is human pathogen, it

In Poland, there are only few *Trichophyton* species, which are common, including:

Among *Microsporum* genera, only few species are common in lab-practice:

 *Trichophyton rubrum* – antropophilic dermatophyte, distributed worldwide, usually specific to human, but infections in animals also have been reported. It may be the cause of practically all infections of body surface areas (with exception of fungal infections of the scalp). Most commonly it causes onychomycosis and athlete`s foot (*tinea pedis*). It may also cause infections of glabrous skin (*tinea corporis*, *tinea faciei*), groin (*tinea cruris*), hands (*tinea manuum*) or nails (*tinea ungiuim*). This fungus causes

 *Trichophyton mentagrophytes* – zoophilic dermatophyte, cosmopolitan fungus, distributed worldwide. It causes infections in animals (cats, dogs, rabbits, guinea pigs, rodents, hedgehogs) as well as in human. Most commonly it causes infections of glabrous skin (*tinea corporis*, *tinea faciei*) and scalp infections (*tinea capitis*). Lesions often

 *Trichophyton tonsurans* – antropophilic species, usually specific to human, practically cosmopolitan. Most commonly it causes infections of the scalp (*tinea capitis*) and it may also cause infections of glabrous skin (*tinea corporis*), especially in the "shower area" on neck, shoulder, back, buttocks, and feet, when inoculum is washed off from head on the other parts of the body, while taking shower. Infections usually proceed with mild inflammatory reaction, but cases with severe inflammatory responses also have been reported. This fungus often causes family and school outbreaks. It is also responsible for infections among wrestlers and judo competitors (*tinea corporis gladiatorum*). This dermatophyte is resistant to the adverse impact of external conditions and it is

 *Trichophyton interdigitale* – antropophilic species, distributed worldwide. It causes infections of feet (aspecially in the interdigital spaces) and hands (*tinea manuum*),

 *Trichophyton verrucosum* – zoophilic species, the mostly isolated from cattle, it infects people, who work with these animals (farmers). Cosmopolitan fungus, it causes diseases of exposed parts of the body (*tinea corporis*) and face (*tinea faciei*), beard (*tinea*

 *Trichophyton violaceum* – antropophilic species, mostly it causes infections of the scalp (*tinea capitis*) and glabrous skin (*tinea corporis*), aspecially in the "shower area". It can also cause onychomycosis. It is specific to human, but it also can be pathogenic for

*Trichophyton schoenleinii* – antropophilic species, it causes *favus*. Nowadays is practically

 *Microsporum canis* – zoophilic species, cosmopolitan, distributed worldwide. It is very contagious aspecially for young cats and dogs. In human it causes infections of the scalp (*tinea capitis*) and beard (*tinea barbae*) or infections of glabrous skin or face (*tinea*

 *Microsporum audouinii* – antropophilic species, cosmopolitian, however, the incidence of fungal infections caused by this pathogen in Poland is very small. It causes infections of the scalp (*tinea capitis*), glabrous skin (*tinea corporis*), face (*tinea faciei*), affecting mostly school-age children (boys:girls=4:1), however cases of dermatomycoses in adults,

In Poland, there are only few *Trichophyton* species, which are common, including:

persistent, chronic infections.

proceed with a large inflammatory reactions.

transferred by asymptomatic carriers.

*barbae*) or head (*tinea capitis*).

unique.

*corporis*, *tinea faciei*).

sometimes it can also infect nails (*tinea unguium*).

animals. It is the cause of family and institutional outbreaks.

Among *Microsporum* genera, only few species are common in lab-practice:

caused by *Microsporum audouinii* also were described. Although it is human pathogen, it was isolated from fur of guinea pigs and rarely, from dog`s fur.

The genera *Epidermophyton* has only one representative, quite often isolated form lesions:

 *Epidemophyton floccosum* – antropophilic species, cosmopolitan. In human it causes mostly infections of the groin (*tinea cruris*), rarely of glabrous skin (*tinea corporis*), feet (*tinea pedis*) and very rarely of toenais (*onychomycosis)*.


**8. Simulation and requirements for artificial intelligence (AI)-aided systems**

AI has to meet several demands to be used widely in clinical practice. The major four requirements that we think, are of paramount importance for AI guiding computer simulations, to be helpful in the field of Oral Radiology, are:

Most AI systems, and therefore computer simulations used in diagnostics that are based on these, today do not meet all requirements, and this is why most applications described in the rapidly growing body of scientific literature on CAD are not widely used in clinical practice.


4.1.2. Access-Control Module

The access-control module is implemented as a root daemon that performs write/delete protection for the files produced by the version-control module each time a file version is created. This is achieved by running the chattr command (Change Attribute) with root privileges. chattr is a command line in Linux that is used to set/unset specific attributes to a file in a Linux environment to secure accidental deletion or modification of important files and folders, even by root users. Through this process, file snapshots are protected from corruption or deletion by using the change file attribute permissions with the immutable flag (i) under the Linux environment, preventing any user, including the root, from accidentally modifying and/or deleting files. An example using this command is shown in Figure 4.

**Figure 4.** An example using chattr command to perform file write/delete protection.

It is important to note that the default setting for standard users is assumed to be nonadmins, with the access-control module configured as a system daemon with root access privileges executing the chattr command; this would inherently ensure the protection of newly created versions in the version-control directory. Any attempt to modify or delete a protected file will not be permitted, as shown in the example in Figure 5. This is considered a valid setting for two reasons: (i) users usually do not log into their systems as admins. In fact, one of the best practices of computer usage emphasizes that users never log in as admins. (ii) A recent report showed that 90% of ransomware instances in the wild could infect systems and encrypt files without administrative privileges [58]. This indicates that while users log in as non-admins, there is still a high possibility that Ransomware may encrypt their files. In our proposed solution, ensuring a specific access control process with administrative privileges will protect files created/edited by non-admin users.

**Figure 5.** The file is immutable when trying to write or delete.

### *4.2. Recovery from Ransomware Attack*

The focus of our framework for ransomware recovery is all about maintaining control of the latest possible versions of the files. As the proposed framework preserves protected versions of the files, we can gain access to the files in case of a ransomware attack. The result of the attack will corrupt the original file or even delete it. However, self-healing is achieved using the proposed SH-VARR framework by retrieving the protected version for each file stored in the version-control directory. In case the original file is deleted or encrypted by Ransomware, our SH-VARR framework allows immediate recovery of the last protected version of the file(s) involved, fulfilling the self-healing property. Based on the proposed framework, the protected snapshots will not be affected and can be recovered under root privileges assumed to be protected. The recovery process is performed by removing the sticky bit attribute to ensure that the file extension is .odt. Recovering a file from the protected versions directory is performed as follows:

### *4.3. Implementation Challenges and Limitations*

Throughout this work, we conducted several experiments to ascertain that our goal of keeping a protected version of our XML-based files was achieved. Having set out to build a distributed version-aware control system for XML-based documents that ensures portability that would not depend on a centralized repository, the implemented approach was indeed found to warrant portability as it keeps a link to the original file as described above. During the implementation phase, the system was found to experience certain limitations, which can be summarized as follows:


**2. Honeybee diseases**

Honeybees are affected by fungal, bacterial, viral (Thai Sac brood) and acarine (*Varroa*) diseases. Antibiotics are generally used to fight bacterial and fungal diseases such as American foulbrood, European foulbrood and nosemosis [3].

American foulbrood is by far the most virulent brood disease known in honeybees. The disease is caused by the spore-forming bacterium, *Paenibacillus larvae*. Larvae up to 3 days old become infected by ingesting spores that are present in their food. Spores germinate in the gut of the larva and the vegetative form of the bacteria begins to grow, taking its nourishment from the larva. Infected larvae normally die after their cell is sealed. The vegetative form of the bacterium, before to die, produces many millions of spores which are extremely resistant to desiccation and can remain viable for more than 40 years in honey and beekeeping equipment. Because of this persistence, in most countries official apiary inspectors are required to burn all infected colonies. Other countries (e.g. USA, Canada, and Argentina) allow the use of antibiotics, such as oxytetracycline and tylosin, to keep the disease in control. However, antibiotics are not a cure or a treatment of the infection since they affect only the vegetative stage of American foulbrood, inhibiting its development in the gut of the larvae. This may prevent the rapid diffusion within a colony.

European foulbrood is closely related to American foulbrood in symptomatology, and until 1906, these two diseases were not differentiated. The causative organism of European foulbrood is the bacterium *Melissococcus plutonius*, which does not produce spores, and therefore, this disease is considered less severe than American foulbrood. European foulbrood occurs primarily in spring when numbers of *M. plutonius* reach their peak. The bacterium is ingested by honey bee larvae and it replicates in mid-gut. If the bacteria out-compete the larva, the larva will die before the cell is capped. Alternatively, the bee may survive until adulthood if the larvae has sufficient food resources. Some antimicrobials, for example, oxytetracycline, have been demonstrated to be an effective treatment.

Nosemosis, caused by the fungus *Nosema apis* or *Nosema ceranae*, is historically considered the most serious disease of adult bees. Infection is acquired when spores are swallowed by bees and infect the epithelial cells of the hind gut, giving rise rapidly to large numbers of spores and impairing the digestion of pollen which shortens the life of honeybees. *N. ceranae* was originally a parasite of the Asian honeybee (*Apis cerana*), but now is widespread in some European regions, too. In recent years, the disappearance of adult honeybees, known as colony collapse disorder, has been devastating a great number of beehives worldwide. This problem has caused serious damage to apiculture and also to agricultural activities that use honeybees as pollinators. Among the possible causes of the disappearance of honeybees, nosemosis has been reported as a primary candidate.