Polyimide: From Radiation-Induced Degradation Stability to Flat, Flexible Devices

Polyimide (PI, PMDA-ODA, C22H11N2O5, Kapton-H), is a class of polymer, extensively used in microelectronics and space technology, due to its exceptional mechanical, dielectric, and chemical properties. In space, PI heat shield experiences a harsh environment of energetic electrons, ultra-violet radiation, and atomic oxygen, causing degradation and erosion. Radiation-assisted physicochemical surface modulations in PI, in view of understanding and reducing the degradation in laboratory-based systems, are discussed in the chapter. Strategies for the design and development of 2D, flat, and flexible electromechanical devices by swift heavy ion induced bulk modifications in PI are also described. Fabrication of a couple of such devices, including their performance analysis, is presented.

Porokeratosis: An enigma beginning to unravel

Porokeratosis is a keratinization disorder with unclear etiopathogenesis, varied clinical presentation and characteristic histopathology, and is usually unresponsive to current therapeutic options. Until now, it was considered to be a clonal disorder with immunity, ultra violet radiation and other factors playing important roles in etiopathogenesis. It is now known that abnormalities in the mevalonate pathway are responsible for this clonal keratinization abnormality. New variants of porokeratosis like eruptive bullous, pruriginous, lichen planus like, follicular variants and porokeratoma have been described. While the cornoid lamella is the classical histopathologic feature, dermoscopy and reflectance confocal microscopy make the diagnosis clearer. Development of malignancy in a few variants is a concern. Linear, disseminated superficial actinic and giant lesions are most prone to developing malignancies. Bowen’s disease, squamous cell carcinoma, basal cell carcinoma and even melanoma have been reported in cases of long-standing porokeratosis. Newer modalities of therapy such as photodynamic therapy, ingenol mebutate and HMGCoA inhibitors may play a role in the future.

DETECTION OF BACTERIOCIN (STAPHYLOCOCCIN) ACTIVITY OF STAPHYLOCOCCUS AUREUS ISOLATES IN CHICKENS.

Twenty isolates of Staphylococcus aureus were examined, fourteen from them showed staphylococcin activity while six isolates were not producers. The staphylococcin activity of potential producer isolates was increased if CaCl2 was incorporated in the medium and if the cultures were induced with ultra violet radiation.

Decontaminating N95/FFP2 masks for reuse during the COVID-19 epidemic: a systematic review

Background With the current COVID-19 pandemic, many healthcare facilities have been lacking a steady supply of filtering facepiece respirators. To better address this challenge, the decontamination and reuse of these respirators is a strategy that has been studied by an increasing number of institutions during the COVID-19 pandemic. Methods We conducted a systematic literature review in PubMed, PubMed Central, Embase, and Google Scholar. Studies were eligible when (electronically or in print) up to 17 June 2020, and published in English, French, German, or Spanish. The primary outcome was reduction of test viruses or test bacteria by log3 for disinfection and log6 for sterilization. Secondary outcome was physical integrity (fit/filtration/degradation) of the respirators after reprocessing. Materials from the grey literature, including an unpublished study were added to the findings. Findings Of 938 retrieved studies, 35 studies were included in the analysis with 70 individual tests conducted. 17 methods of decontamination were found, included the use of liquids (detergent, benzalkonium chloride, hypochlorite, or ethanol), gases (hydrogen peroxide, ozone, peracetic acid or ethylene oxide), heat (either moist with or without pressure or dry heat), or ultra violet radiation (UVA and UVGI); either alone or in combination. Ethylene oxide, gaseous hydrogen peroxide (with or without peracetic acid), peracetic acid dry fogging system, microwave-generated moist heat, and steam seem to be the most promising methods on decontamination efficacy, physical integrity and filtration capacity. Interpretation A number of methods can be used for N95/FFP2 mask reprocessing in case of shortage, helping to keep healthcare workers and patients safe. However, the selection of disinfection or sterilization methods must take into account local availability and turnover capacity as well as the manufacturer; meaning that some methods work better on specific models from specific manufacturers. Systematic registration number CRD42020193309.

Enhanced Protease Production from Rummeliibacillus Stabekisii (TWSS-P-2) Strain through Mutagenesis and Optimized Culture Conditions

Identification of proper microbial sources and optimizing the enzyme production conditions are essential for industrial-scale enzyme production. The present study was done to identify and enhance the production of protease enzyme from an important microbial source Rummeliibacillus stabekisii (TWSS-P-2). Ultra-violet radiation physical method and ethyl methanesulfonate and ethidium bromide dependent chemical methods were considered for mutagenesis. Enzyme assay-dependent screening resulted in identifying Rummeliibacillus stabekisii (TWSS-P-2) as the best strain with optimum protease production that was improved through the chemical treatment mentioned. The strains were tested under various physical and chemical factors including carbon source, nitrogen source, inoculum sizes, pH, temperature to optimize the production of the protein. Submerged fermentation (SmF) was used to assess enzyme production. We were successful in deriving the optimum condition for the protease enzyme production for Rummeliibacillus stabekisii (TWSS-P-2) and the mutagenic effect yielded 2-4 fold better enzyme production.

Kinetics and mechanism of oxidative decomposition of Congo red by Fenton’s reagent and its synergic effects on exposure to UV radiation

Congo red is a toxic azo dye which is used extensively in industries like textile, paper, pulp and paper. Very high amount of Congo red from these industrial sources is discharged into natural water bodies resulting environmental pollution. The present work reports the kinetics and mechanism of oxidative decomposition of Congo red by Fenton’s reagent in homogeneous medium and also under ultra violet light irradiation. Kinetic parameters like effect of [Fe2+], [H2O2], [Congo red] and temperature on the decomposition of Congo red were studied. The reaction is found to be fractional order with [Fe2+] and first order with [H2O2] and [Congo red]. The rate of oxidative decomposition of Congo red by Fenton’ reagent showed a rapid increase of three times when irradiated with ultra violet radiation and completion of reaction occurred within 5-6 minute. Various thermodynamic variables were determined and the presence of isosbestic points on sequential scanning of oxidation kinetics proves that the reaction is very smooth, spontaneous and endothermic. A suitable mechanism is suggested based on the experimental results obtained.

A systematic review and meta-analysis on correlation of weather with COVID-19

This study presents a systematic review and meta-analysis over the findings of significance of correlations between weather parameters (temperature, humidity, rainfall, ultra violet radiation, wind speed) and COVID-19. The meta-analysis was performed by using ‘meta’ package in R studio. We found significant correlation between temperature (0.11 [95% CI 0.01–0.22], 0.22 [95% CI, 0.16–0.28] for fixed effect death rate and incidence, respectively), humidity (0.14 [95% CI 0.07–0.20] for fixed effect incidence) and wind speed (0.58 [95% CI 0.49–0.66] for fixed effect incidence) with the death rate and incidence of COVID-19 (p < 0.01). The study included 11 articles that carried extensive research work on more than 110 country-wise data set. Thus, we can show that weather can be considered as an important element regarding the correlation with COVID-19.

Effect of ultraviolet radiation on the skin

The beneficial effect of ultraviolet radiation on our skin manifests itself in the synthesis of vitamin D. However, the detrimental effect of this radiation is much more severe. A longer duration of the effect of this radiation speeds up photoaging of skin depending on its phonotype. Symptoms of burning accompanied by tiredness, headaches, changes in temperature, skin damage observed testify to the negative effect of ultra-violet radiation. The unsuitable acquisition of measures of protection with SPF (Sun Protection Factor) numbers and their seasonal application presuppose the formation of wrinkles. This issue remains relevant today as well, because the results of ultraviolet radiation are diagnosed ever more often. They testify to careless skin care. The slightest skin redness, swelling or brownness is reaction of the skin to harmful ultraviolet radiation. The aim of the investigation was to examine the effect of ultraviolet radiation on skin. The investigation was carried out in virtual space on the Internet website www.apklausa.lt in 2021 (2 months). A total of 209 respondents took part in the investigation. The results and conclusions of the investigation are as follows: due to the nature of work, about half of the respondents were exposed to ultraviolet radiation the whole day or 3–4 hours a day. One the third of the respondents used the solarium procedures once per week, provided themselves with measures of protection in shops; however, they did not set great store by the protective effect of SPF filters. One the sixth of the respondents used measures of protection when their skin suffered serious damage.

Arctic on the verge of an ozone hole?

Severe vortex-wide ozone loss in the Arctic would expose nearly 650 million people and ecosystem to unhealthy ultra-violet radiation levels. Adding to these worries, and extreme weather events as the harbingers of climate change, clear signature of an ozone hole (ozone column values below 220 DU) appeared over the Arctic in March and April 2020. Sporadic occurrences of ozone hole values at different regions of vortex for almost three weeks were found for the first time in the observed history in the Arctic. Furthermore, a record-breaking ozone loss of about 2.0–3.4 ppmv triggered by an unprecedented chlorine activation (1.5–2.2 ppbv) matching to the levels of Antarctic ozone hole conditions was also observed. The polar processing situation led to the first-ever appearance of loss saturation in the Arctic. Apart from these, there were also ozone-mini holes in December 2019 and January 2020 driven by atmospheric dynamics. The large loss in ozone in the colder Arctic winters is intriguing and that demands rigorous monitoring of the region. Our study suggests that the very colder Arctic winters in near future would also very likely to experience even more ozone loss and encounter ozone hole situations, provided the stratospheric chlorine levels still stay high there.