Poly(L-lactide-co-caprolactone)/collagen electrospun mat: Potential for wound dressing and controlled drug delivery

Here we report a novel bioactive electrospun mat based on poly(L-lactide-co-caprolactone) (PLLC) and collagen for wound dressing and sustained drug delivery of gentamicin. PLLC/collagen electrospun mat loaded with 10% gentamicin showed bioactivity for 15 days against Gram-positive and Gram-negative bacteria. The in vitro cell culture of 3T3 fibroblasts confirmed that these electrospun mat provide an increased specific interface area and hydrophilicity to enhance cell attachment, proliferation, and migration. The modified PLLC/collagen mat provided an excellent enhancement in properties of antibacterial wound dressings with a minimum in vitro toxicity and high potency for promoting wound healing stages.     

Nanomaterials in food and agriculture: An overview on their safety concerns and regulatory issues

Nanotechnology has seen exponential growth in last decade due to its unique physicochemical properties; however, the risk associated with this emerging technology has withdrawn ample attention in the past decade. Nanotoxicity is majorly contributed to the small size and large surface area of nanomaterials, which allow easy dispersion and invasion of anatomical barriers in human body. Unique physio-chemical properties of nanoparticles make the investigation of their toxic consequences intricate and challenging. This makes it important to have an in-depth knowledge of different mechanisms involved in nanomaterials's action and toxicity. Nano-toxicity has various effects on human health and diseases as they can easily enter into the humans via different routes, mainly respiratory, dermal, and gastrointestinal routes. This also limits the use of nanomaterials as therapeutic and diagnostic tools. This review focuses on the nanomaterial–cell interactions leading to toxicological responses. Different mechanisms involved in nanoparticle-mediated toxicity with the main focus on oxidative stress, genotoxic, and carcinogenic potential has also been discussed. Different methods and techniques used for the characterization of nanomaterials in food and other biological matrices have also been discussed in detail. Nano-toxicity on different organs—with the major focus on the cardiac and respiratory system—have been discussed. Conclusively, the risk management of nanotoxicity is also summarized. This review provides a better understanding of the current scenario of the nanotoxicology, disease progression due to nanomaterials, and their use in the food industry and medical therapeutics. Briefly, the required rules, regulations, and the need of policy makers has been discussed critically.     

Equitable Gender Participation in Local Water Governance: An Insight into Institutional Paradoxes

The participation of local stakeholders in governance of water resources is regarded as inalienable for ensuring efficiency, effectiveness and sustainability. To enhance gender balance in the water governance process, institutions are being designed and executed globally to elicit enhanced participation of women. This paper contends that in the context of local communities, the new institutional framework is divorced from the traditional social institutions that in turn operationalize their resource management systems. Based upon empirical evidence from rural Indian setting, the paper deciphers the paradoxes between the two sets of institutional paradigms and illustrates how these paradoxes at the ‘interface’ between the local community context and the development strategy lead to problems with effective women’s participation. On the basis of the findings, it argues that the institutional paradigm for achieving equitable gender participation in local water governance does not represent a truly ‘bottom-up’ approach. It further raises the concern that if the institutional paradigm for participation is contradictory to local institutions, then how can the objectives of participation founded thereupon be seen as achievable? The paper proposes the need to design participatory paradigms that are more realistically rooted in community-based institutional frameworks so as to enhance effectiveness of the endeavors.     

Disparities in publication patterns by gender, race and ethnicity based on a survey of a random sample of authors

Gender and racial disparities have greatly diminished in academia over the last 30 years, but attrition rates among women and minority faculty still remain high. In this paper we examine gender and racial disparities in publishing, an activity that is important for career advancement, but has not been incorporated adequately into the debate on faculty attrition. We surveyed a random sample of 1,065 authors who contributed a peer-reviewed journal article indexed in the Web of Science (WoS) in 2005 and at least one other article during the period of 2001–2004 in four academic disciplines representing natural sciences (biochemistry and water resources) and social sciences (anthropology and economics). We then report on the relationships between demographic variables (gender and race/ethnicity) and career-related variables (academic rank, discipline, and h-index) of these authors. Our findings show that at every career level and within each discipline, women were under-represented in academic positions compared to men and an even lower percentage of women published at each academic level than were employed at that level. Further, we found that women had lower h-indices than men in all four disciplines surveyed. Societal and biological constraints may reduce women’s ability to obtain research intensive positions and contribute to these gender disparities. Hispanics and blacks were underrepresented among individuals awarded with doctoral degrees, doctorate recipients employed in academia, and academics publishing in WoS as compared to their representation in the population. Whites, Asians, and Native Americans and Pacific Islanders were adequately or over-represented in each category. Additionally, blacks had lower h-indices than the other ethnic groups across the disciplines surveyed. Compared to women, attrition among blacks and Hispanics appears to occur earlier in their career development. Cumulative experiences with discrimination and stereotypes may partly explain higher attrition and lower publication productivity among blacks and Hispanics.     

Effect of Excipient and Processing Variables on Adhesive Properties and Release Profile of Pentoxifylline From Mucoadhesive Tablets

ABSTRACT

The bioavailability and onset of action of drugs with high first-pass metabolism can be significantly improved by administration via the sublingual route. The objective of this study was to evaluate the effect of polymer type and tablet compaction parameters on the adhesive properties and drug release profile from mucoadhesive sublingual tablet formulations. Pentoxifylline was selected as the model drug because it has poor oral bioavailability due to extensive first-pass metabolism. Two polymers known to possess mucoadhesive properties, carbomer and hydroxypropyl methyl cellulose (HPMC), were used to prepare the formulations. Tablets were prepared by using direct compression technique and evaluated for in vitro dissolution, drug-excipient interactions, and adhesive properties. In general, there was a decrease in the rate of drug release with an increase in the concentration of polymers. No drug-excipient interactions were evident from differential scanning calorimetry or high-performance liquid chromatography analysis. For the formulations containing HPMC, the force of mucoadhesion increased with an increase in the concentration of polymer; however, for carbomer formulations, no such correlation was observed. Force of mucoadhesion decreased as a function of hydration time in both of the polymers.     

Influence of undulating wall heat and mass flux on MHD natural convection boundary layer flow from a vertical wall

Current study expounds an unsteady magnetohydrodynamic natural convective flow along a vertical wall in presence of variable transverse magnetic field. Small amplitude undulation in wall heat flux and wall mass flux are imposed at the vertical wall to generate the boundary layer flow. The flow governing equations are divided into sets of steady and unsteady equations and then transformed into the similarity and nonsimilarity equations, respectively, by introducing stream function formulations. The sets of nonsimilarity equations are solved numerically by using three different techniques, namely, perturbation solution technique, asymptotic solution technique and implicit finite difference technique applied, respectively, for lower, higher, and all frequencies (ξ). Results are illustrated in connection with the amplitude and phase angles of shear stress, wall temperature, and concentration against the frequency (ξ) for wide ranges of physically significant parameters. Likening of the results obtained by above mentioned numerical methods are presented in every figure and table. Results reveal that the amplitude of undulating shear stress and wall temperature dwindle and the amplitude of wall concentration increases due to increment in Prandtl number (Pr). Besides, on incrementing Schmidt number (Sc) the amplitude of undulating shear stress and wall concentration dwindle and the amplitude of wall temperature increases. Results also reveal that on incrementing magnetic parameter (M) the amplitude of transient shear stress dwindles while the amplitude of transient wall temperature and concentration increase.     

Accelerated degradation in amorphous silicon solar cells by a combination of current injection and light insolation

A new degradation technique for amorphous silicon solar cells comprising of a combination of current injection and insolation has been developed. Compared to the conventional light degradation technique, current-induced degradation which involves forward biased current stress, results in a lower stabilized cell parameters including efficiency. This stabilized efficiency is, however, independent of the amount of current injected. The excess degradation is recovered under light illumination. The stabilized value of the conversion efficiency is within experimental error identical to that observed in long term, illumination only degradation. The method is fast, accurate and reliable. Its reliability has also been tested for single junction solar cells having intrinsic layers of different band gaps, as well.     

Biological removal of arsenic pollution by soil fungi

Fifteen fungal strains were isolated from arsenic contaminated (range 9.45-15.63 mg kg^− 1) agricultural soils from the state of West Bengal, India. Five fungal strains were belonged to the Aspergillus and Trichoderma group each, however, remaining five were identified as the Neocosmospora, Sordaria, Rhizopus, Penicillium and sterile mycelial strain. All these fungal strains were cultivated on medium supplemented with 100, 500, 1000, 5000 and 10,000 mg l^− 1 of sodium arsenate. After 30-day cultivation under laboratory conditions, radial growth of these strains was determined and compared with control. Toxicity and tolerance of these strains to arsenate were evaluated on the basis of tolerance index. Out of fifteen, only five fungal strains were found resistant and survived with tolerance index pattern as 0.956 (sterile mycelial strain) > 0.311 (Rhizopus sp.) > 0.306 (Neocosmospora sp.) > 0.212 (Penicillium sp.) > 0.189 (Aspergillus sp.) at 10,000 mg l^− 1 of arsenate. The arsenic removal efficacy of ten fungal strains, tolerant to 5000 mg l^− 1 arsenate, was also assayed under laboratory conditions for 21 days. All these strains were cultivated individually on mycological broth enriched with 10 mg l^− 1 of arsenic. The initial and final pH of cultivating medium, fungal biomass and removal of arsenic by each fungal strain were evaluated. Fungal biomass of ten strains removed arsenic biologically from the medium which were ranged from 10.92 to 65.81% depending on fungal species. The flux of biovolatilized arsenic was determined indirectly by estimating the sum of arsenic content in fungal biomass and medium. The mean percent removal as flux of biovolatilized arsenic ranged from 3.71 to 29.86%. The most effective removal of arsenic was observed in the Trichoderma sp., sterile mycelial strain, Neocosmospora sp. and Rhizopus sp. fungal strains. These fungal strains can be effectively used for the bioremediation of arsenic-contaminated agricultural soils.     

A computer analysis of double junction solar cells with a-Si : H absorber layers

An integrated electrical-optical model has been used to examine the design of double junction solar cells, where the component cells have a-Si : H absorber layers of identical material quality in the initial state. The model takes into account both specular interference effects; and diffused reflectances and transmittances due to interface roughness. The carrier transport at the junction between the two p–i–n subcells is simulated with the help of a thin heavily defective “recombination” layer with a reduced mobility gap.Analysis of the transport properties as a function of position in the device indicates that for the highest double junction cell efficiency the thicknesses of the absorber layers of the component subcells are such that the electric fields over these absorber layers are high simultaneously. Our results also show that whereas in the initial state, the open-circuit voltage and the fill factor of the double junction cell are heavily dependent on the electric field in the thicker bottom subcell; in the light-stabilised state, the more degraded top subcell plays an important role in limiting double junction cell performance. The quantum efficiency under AM 1.5 bias light has been shown to be very sensitive to thickness variations of the component subcells. Using this tool we have arrived at a simplified procedure for designing the double junction structure likely to exhibit the highest efficiency in the stabilised state.