Effect of the presence of excess ammonium ions on the clay surface on permeation properties of epoxy nanocomposites

Epoxy nanocomposites with commercially and self-modified montmorillonites of different cation exchange capacities carrying ammonium modifications of various chemical architectures were synthesized using solution casting approach. The commercially treated montmorillonites were observed to contain a large excess of unbound ammonium ions on the surface, which had a negative impact on the permeation properties of the composites owing to the suspected interactions of these unbound ammonium ions with the epoxy polymer. The permeation behavior was significantly improved when self-modified clays free of any excess ammonium modification were used. The microstructure development was unaffected by the physical state of the clay surface indicating that the potential changes in the polymer properties at the interface as well as interfacial interactions in the composites carrying the commercially modified clays may have led to increase in the free volume. Optimal preparation of the clay surface holds the key to achieve enhancement in the composite performanc

PNIPAAM grafted particle monoliths: parameters affecting structure and morphology

Crosslinked polystyrene latex particles generated with surfactant free emulsion polymerization were functionalized with thin layer of ATRP initiator on the surface. The functionalized particles were aggregated as physical networks using high shear techniques. The latex particles as well as the aggregated particles were used to successfully generate thermo-responsive monoliths by grafting PNIPAAM brushes from the surface of the particles by atom transfer radical polymerization and simultaneous crosslinking of these brushes. Different solid fractions and drying conditions were used in the generation of the monoliths and the effect of these variations on the structure and morphology of the monoliths was analyzed. Surprising morphologies consisting of tubes or channels were observed when higher solid fractions were used. This behavior was enhanced when the monoliths were dried at higher temperatures. By using proper solid fractions and drying conditions, homogenous porous monoliths could be achieve

Evaluation of serum lipid profile in cases of pre-eclampsia and eclampsia

Background: According to the current knowledge, rise in the serum triglyceride level is a major contributor in the pathogenesis of preeclampsia and eclampsia. The present study was designed to compare the changes in lipid profile in normal pregnancy, pre-eclampsia & eclampsia cases.Methods: A case control study was done consisting of total 100 study subjects, 75 already diagnosed pre-eclamptic & eclamptic women and 25 normotensive pregnant women. Age range was 18-35 years, gestational age 28 weeks to term were included. Serum Total Cholesterol (TC), triglyceride and HDL-cholesterol by enzymatic colorimetric method were done.Results: Results showed that level of serum triglycerides in mild pre-eclampsia (156.22 ± 66.5 mg/dl), severe pre-eclampsia (168.30 ± 68.1 mg/dl) & eclampsia (224.89 ± 84.40 mg/dl) as compared to normal pregnant women (130.95 ± 44.64 mg/dl) was increased significantly (P <0.05). Other parameters TC, HDL-C, LDL-C were not changed significantly.Conclusions: The findings of the present study are consistent with previous studies, suggesting increased levels of serum triglyceride as an important factor in the pathological process of preeclampsia & eclampsia. This may help in developing strategies for prevention or early diagnosis of the disorder

Dynamic characterization of cellulose nanofibrils in sheared and extended semi-dilute dispersions

New materials made through controlled assembly of dispersed cellulose nanofibrils (CNF) has the potential to develop into biobased competitors to some of the highest performing materials today. The performance of these new cellulose materials depends on how easily CNF alignment can be controlled with hydrodynamic forces, which are always in competition with a different process driving the system towards isotropy, called rotary diffusion. In this work, we present a flow-stop experiment using polarized optical microscopy (POM) to study the rotary diffusion of CNF dispersions in process relevant flows and concentrations. This is combined with small angle X-ray scattering (SAXS) experiments to analyze the true orientation distribution function (ODF) of the flowing fibrils. It is found that the rotary diffusion process of CNF occurs at multiple time scales, where the fastest scale seems to be dependent on the deformation history of the dispersion before the stop. At the same time, the hypothesis that rotary diffusion is dependent on the initial ODF does not hold as the same distribution can result in different diffusion time scales. The rotary diffusion is found to be faster in flows dominated by shear compared to pure extensional flows. Furthermore, the experimental setup can be used to quickly characterize the dynamic properties of flowing CNF and thus aid in determining the quality of the dispersion and its usability in material processes.Comment: 45 pages, 13 figure

Using a Discrete Choice Experiment to Elicit the Demand for a Nutritious Food: Willingness-to-Pay for Orange Maize in Rural Zambia

Using a discrete choice experiment, this paper estimates the willingness to pay for biofortified orange maize in rural Zambia. The study design has five treatment arms, which enable an analysis of the impact of nutrition information, comparing the use of simulated radio versus community leaders in transmitting the nutrition message, on willingness to pay, and to account for possible novelty effects in the magnitude of premiums or discounts. The estimation strategy also takes into account lexicographic preferences of a subset of our respondents. The results suggest that (a) orange maize is well liked and can compete with white maize in the absence of a nutrition campaign, (b) there is a premium for orange maize with nutrition information, and (c) the mode of nutritional-message dissemination does not have a large impact on consumer acceptance, and (d) novelty effects do not translate into higher willingness to pay for orange maize.

Experimental Validation of the Predicted Binding Site of Escherichia coli K1 Outer Membrane Protein A to Human Brain Microvascular Endothelial Cells: Identification of Critical Mutations That Prevent E. coli Meningitis

Escherichia coli K1, the most common cause of meningitis in neonates, has been shown to interact with GlcNAc1–4GlcNAc epitopes of Ecgp96 on human brain microvascular endothelial cells (HBMECs) via OmpA (outer membrane protein A). However, the precise domains of extracellular loops of OmpA interacting with the chitobiose epitopes have not been elucidated. We report the loop-barrel model of these OmpA interactions with the carbohydrate moieties of Ecgp96 predicted from molecular modeling. To test this model experimentally, we generated E. coli K1 strains expressing OmpA with mutations of residues predicted to be critical for interaction with the HBMEC and tested E. coli invasion efficiency. For these same mutations, we predicted the interaction free energies (including explicit calculation of the entropy) from molecular dynamics (MD), finding excellent correlation (R^2 = 90%) with experimental invasion efficiency. Particularly important is that mutating specific residues in loops 1, 2, and 4 to alanines resulted in significant inhibition of E. coli K1 invasion in HBMECs, which is consistent with the complete lack of binding found in the MD simulations for these two cases. These studies suggest that inhibition of the interactions of these residues of Loop 1, 2, and 4 with Ecgp96 could provide a therapeutic strategy to prevent neonatal meningitis due to E. coli K1

A review of challenges from increasing renewable generation in the Indian Power Sector: Way forward for Electricity (Amendment) Bill 2020

About 70% of India’s current energy mix comprises of coal, and the increase in generation from renewable (RE) sources is affecting the health of the power system. We investigated this effect through the lens of asset utilisation, cost and the social disruption caused by accelerating RE into the Indian Power System. Our review-driven analysis revealed that increasing RE generation is pushing the coal plants to operate in low-loading conditions, causing heightened wear and tear of the plant as they are not suitable for flexible operation. The novel analysis of social disruption due to market parity between RE and coal-based generation presented a holistic view of the political economy of Indian Power System. We found that transition from coal to RE may have extended socio-political ramifications that can potentially disrupt the national economy at an unprecedented scale. Policy implications outlined by our study for the draft Electricity (Amendment) Bill 2020 include scoping a socio-technical framework which supports just energy transition through better financial support mechanisms for flexible operation of coal plants. Focusing on clean-up over shut-down of coal plants and facilitating investments in battery storage technologies and cross-border electricity trade as RE and conventional fuel reach market parity. Bill and Melinda Gates Foundation [OPP1144] and Energy Transition Small Grant by Isaac Newton Trus

A review of challenges from increasing renewable generation in the Indian Power System

About 70% of India’s current energy mix comprises of coal, and the increase in generation from renewable energy (RE) sources is affecting the health of the power system. We investigated this effect through a cross-sectional of asset utilisation, cost and the social disruption caused by accelerating RE into the Indian Power System. We also derived a challenge-roadmap for the power system using bibliometric analysis. The review-driven interpretivist results revealed that increasing RE generation is pushing the coal plants to operate in low-loading conditions, causing heightened wear and tear of the plant as they are not suitable for flexible operation. It had tremendously increased the operation and maintenance costs of the brownfield plants. While there is a growing scope for cross border trade of electricity, the existing regulatory mechanism poses severe implementation challenges. Social disruption due to shift from coal-economy illustrated a holistic view of the political economy of the Indian power system that can potentially cause large-scale conflict and disrupt the national economy at an unprecedented scale. Policy implications outlined by our study for the draft Electricity (Amendment) Bill 2020 include scoping a socio-technical framework which supports just energy transition through better financial support mechanisms for flexible operation of coal plants. Focusing on clean-up over shut-down of coal plants and facilitating investments in battery storage technologies and cross-border electricity trade as RE and conventional fuel reach market parity