Application of superomniphobic finishes on fabrics for chemical protection

Military personnel on patrol and industrial staff are likely to face various hazards from chemicals that can either kill them outright or cause them serious damage. Chemical substances known as chemical warfare agents (CWA) have been used in war zones since the end of the First World War. These chemical warfare agents are particularly dangerous to human life. They cause skin disease, disability and death of soldiers. These chemicals are also widely used for pharmaceutical purposes, for preparation in industrial plants, in laboratories, in nuclear plants and in food items. However, these chemicals cause toxic effects not only to human life but also to the environment as they have polluted widely including buildings, filtration systems, vehicles and equipment. The chemicals spread easily in the environment and remain for a long time. Finally, CWA was banned from use in 1996, but some of them are still being used in the warzone. Protection of people from exposure to hazardous chemicals, such as chemical warfare agents and toxic or corrosive chemicals is essential in today’s battlefield and industries. Chemical, biological, radiation and nuclear (CBRN) suits are designed for emergency circumstances and are likely to cause a thermal burden when worn over prolonged periods. Special protective clothing is available for use to protect from these chemicals but it is very heavy in weight, uncomfortable and expensive. Exploration of the superomniphobic surface for versatile protection against water, oil, liquids and chemicals has been the key to the development of protective clothing for chemical protection. However, simple, cost-effective methods to develop functional surface on textiles with durability and without compromising comfort much are still of great challenge. This research aims at developing protective fabrics with a functional coating that is capable of preventing the penetration of water, liquids, oil and certain chemical warfare agents without compromising the fabric weight and comfort properties. The intention of this research is not to develop a replacement for CBRN suits but to develop low-level threat fabrics that can either be used as combat uniforms and selective parts of the uniform or be applied in industrial protection. A widely used coating method of padding-knife coating-padding-curing was employed in this research to perform functional coating on fabrics towards high-performance protective clothing. Polymeric coating of polyurethane or silicone rubber membrane in combination with repellents including polydimethylsiloxane (PDMS), trimethylated silica (TMS) and fluoro-polymers was developed to form superomniphobic surface on cotton and polycotton fabrics, and a comparison with coated fabrics with plasma treated fabrics and industrial fabrics was performed to justify the developed technology from this research. The coated fabrics were characterised by thickness, morphology and chemical components to understand the structure and mechanism of the coating. Measurements of protection against water, oil, aqueous liquids and chemicals and hydrostatic pressure were performed to test the versatile protection of the coated fabrics. Besides, the air permeability, water vapour permeability, thermal resistance, handle, stiffness and moisture management properties were tested to study of the comfort of the coated fabrics. It was found that the combination of polyurethane membrane and PDMS-TMS acted as repellents to give better results in terms of protection against water, liquids, oil, chemical, hydrostatic pressure on the fabric surface. The developed surface presented hydrophobicity with a water contact angle of around 150o, and the droplets of water, oil, aqueous liquids and chemicals were repelled for long periods. A cross-linked network was formed between the membrane and the PDMS-TMS, resulted in the excellent durability of the coating against different cycles of laundering and crocking together with rubbing. The comfort of the coated fabrics was compromised due to the blocking of the porous structure of the fabrics, but the selection of the coated membrane such as the thermoplastic polyurethane would improve the comfort to some extent. The coated fabrics were comparable to the plasma treated fabrics for defence and industrial fabrics in terms of protection and the coated fabrics can withstand much higher hydrostatic pressure than the other two. The advent of high-performance coating was suitable for long time protection for chemical as well as comfortable properties for the protective clothing for military and industry

Space Charge–Limited Current Model for Polymers

Polymers have exceptional charge transport mechanism as a combination of delocalization and localization of charge carriers with intramolecular and intermolecular charge interaction, respectively, and most of the time, it is interpreted with Mott-Gurney space charge–limited current model. As polymers are full of traps, therefore, Mott-Gurney space charge–limited model is modified with various trap distributions as trapped space charge–limited model. The most crucial parameter affected by the nature and distribution of traps is the carrier mobility, and it is argued that space charge–limited model is an acceptable choice for the mobility measurement for polymer. Similarly, in order to account the commonly observed lowering of trap barrier height at higher electric field, the Mott-Gurney space charge–limited current is further modified with little variations, which are evaluated and discussed in detail

The frequency of heparin induced thrombocytopenia in patients undergoing elective cardiac bypass surgeries

OBJECTIVE: To determine the frequency of Heparin Induced Thrombocytopenia (HIT) in patients undergoing elective cardiac bypass surgeries and to observe the platelets evolution post surgically in these patients. METHOD: A prospective study was designed and 100 unselected consecutive patients undergoing elective cardiac bypass surgery were enrolled and evaluated. The clinical and laboratory details were noted before and after surgery. Their platelet counts were observed from day 0 (prior to surgery) to day 5 post operatively. Particle gel immunoassay was used to demonstrate the presence of antibodies against heparin-platelet factor 4 complexes. RESULTS: There were 86 males and 14 females with median age of 59 and 53.5 years respectively. Marked platelet count variation was detected during post operative period in all patients (n=100) ranging from 23 +/- SD 186.73 to 389 +/- 84.12 X 109/L. However, 20 patients showed \u3e50% drop on day 5 and seven of these also showed seroconversion. The clinical scoring for HIT was found to have a good negative predictive value. Thromboembolic complications were not observed in any of our patients. CONCLUSIONS: HIT is prevalent to a significant extent in patients after cardiac surgery in our clinical setting though it mostly remains undetected and is an under-diagnosed entity

Colonic miRNA Expression/Secretion, Regulated by Intestinal Epithelial PepT1, Plays an Important Role in Cell-to-Cell Communication during Colitis

PepT1 is a member of the proton-oligopeptide cotransporter family SLC15, which mediates the transport of di/tripeptides from intestinal lumen into epithelial cells. MicroRNAs (miRNAs), a small noncoding RNAs (21–23 nucleotides), posttranscriptionally regulate gene expression by binding to the 39-untranslated regions (UTRs) of their target mRNAs. Although the role of most miRNAs remains elusive, they have been implicated in vital cellular functions such as intestinal epithelial cells differentiation, proliferation, and apoptosis. In the present study, we investigated the effect of intestinal epithelial PepT1 expression on microRNA (miRNA) expression/secretion in the colons of control mice and in mice with experimentally induced colonic inflammation (colitis). The colonic miRNA expression was deregulated in both colitis and control mice but the deregulation of miRNA expression/secretion was specific to colonic tissue and did not affect other tissues such as spleen and liver. Intestinal epithelial PepT1-dependent deregulation of colonic miRNA expression not only affects epithelial cells but also other cell types, such as intestinal macrophages. Importantly, we found the miRNA 23b which was known to be involved in inflammatory bowel disease was secreted and transported between cells to impose a gene-silencing effect on recipient intestinal macrophages. Based on our data, we may conclude that the expression of a specific protein, PepT1, in the intestine affects local miRNA expression/secretion in the colon on a tissue specific manner and may play an important role during the induction and progression of colitis. Colonic miRNA expression/secretion, regulated by intestinal epithelial PepT1, could play a crucial role in cell-to-cell communication during colitis

Cellular energy status is indispensable for perillyl alcohol mediated abrogated membrane transport in Candida albicans

The prevalence of fungal infections and their resistance patterns in fungal isolates from large number of patients with impaired immunity still remains poorly monitored. In spite of significant advances being made in the improvement of antifungal drugs, only a limited number of antifungal drugs are currently available. The present study aimed to gain further mechanistic insights into the previously described anticandidal activity of natural monoterpenoid, perillyl alcohol (PA). We found that cellular transport across cell membrane was abrogated in presence of PA. This was demonstrated by dose and time dependent enhanced cellular leakage accompanied by inhibited sodium and potassium cellular transport. In addition, we found disrupted pH homeostasis which was depicted by enhanced extracellular pH. We further observed that mitochondrial energy status is highly integrated with the antifungal activity of PA. This was evident from inhibited propidium iodide (PI) uptake in presence of sodium azide and di-nitro phenol (DNP) which showed no fluorescence when treated with PA. Moreover, we observed that PA leads to disrupted mitochondrial membrane potential. Additional cell death hallmarks in response to PA such as nuclear fragmentation was also observed with 4\u27,6-diamidino-2-phenylindole (DAPI) staining. Taken together, PA is a novel candidate that deserves further attention to be exploited as effective antifungal agent of pharmacological interest

Dextran Sodium Sulfate (DSS) Induces Colitis in Mice by Forming Nano-Lipocomplexes with Medium-Chain-Length Fatty Acids in the Colon

Inflammatory bowel diseases (IBDs), primarily ulcerative colitis and Crohn's disease, are inflammatory disorders caused by multiple factors. Research on IBD has often used the dextran sodium sulfate (DSS)-induced colitis mouse model. DSS induces in vivo but not in vitro intestinal inflammation. In addition, no DSS-associated molecule (free glucose, sodium sulfate solution, free dextran) induces in vitro or in vivo intestinal inflammation. We find that DSS but not dextran associated molecules established linkages with medium-chain-length fatty acids (MCFAs), such as dodecanoate, that are present in the colonic lumen. DSS complexed to MCFAs forms nanometer-sized vesicles ∼200 nm in diameter that can fuse with colonocyte membranes. The arrival of nanometer-sized DSS/MCFA vesicles in the cytoplasm may activate intestinal inflammatory signaling pathways. We also show that the inflammatory activity of DSS is mediated by the dextran moieties. The deleterious effect of DSS is localized principally in the distal colon, therefore it will be important to chemically modify DSS to develop materials beneficial to the colon without affecting colon-targeting specificity

A Phased Approach for Assessing Combined Effects from Multiple Stressors

We present a phased approach for evaluating the effects of physical, biological, chemical, and psychosocial stressors that may act in combination. Although a phased concept is common to many risk-based approaches, it has not been explicitly outlined for the assessment of combined effects of multiple stressors. The approach begins with the development of appropriate conceptual models and assessment end points. The approach then proceeds through a screening stage wherein stressors are evaluated with respect to their potential importance as contributors to risk. Stressors are considered individually or as a combination of independent factors with respect to one or more common assessment end points. As necessary, the approach then proceeds to consider interactions among stressors. We make a distinction between applications that begin with effects of concern (effects based) or with specific stressors (stressor based). We describe a number of tools for use within the phased approach. The methods profiled are ones that have been applied to yield results that can be communicated to a wide audience. The latter characteristic is considered especially important because multiple stressor problems usually involve exposures to communities or to ecologic regions with many stakeholders