Inhibitor of Sarco/Endoplasmic Reticulum Calcium-ATPase Impairs Multiple Steps of Paramyxovirus Replication

Sarco/endoplasmic reticulum calcium-ATPase (SERCA) is a membrane-bound cytosolic enzyme which is known to regulate the uptake of calcium into the sarco/endoplasmic reticulum. Herein, we demonstrate for the first time that SERCA can also regulate virus replication. Treatment of Vero cells with SERCA-specific inhibitor (Thapsigargin) at a concentration that is nontoxic to the cells significantly reduced Peste des petits ruminants virus (PPRV) and Newcastle disease virus (NDV) replication. Conversely, overexpression of SERCA rescued the inhibitory effect of Thapsigargin on virus replication. PPRV and NDV infection induced SERCA expression in Vero cells, which could be blocked by Thapsigargin. Besides inducing enhanced formation of cytoplasmic foci, Thapsigargin was shown to block viral entry into the target cells as well as synthesis of viral proteins. Furthermore, NDV was shown to acquire significant resistance to Thapsigargin upon long-term passage (P) in Vero cells. As compared to the P0 and P70-Control, the fusion (F) protein of P70-Thapsigargin virus exhibited a unique mutation at amino acid residue 104 (E104K), whereas no Thapsigargin-associated mutations were observed in HN gene. To the best of our knowledge, this is the first report describing the virus-supportive role of SERCA and a rare report suggesting that viruses may acquire resistance even in the presence of an inhibitor that targets a cellular factor

A Precise physics-based compact model for 2-DEG charge density in GaAs HEMTs applicable in all regions of device operation

In this paper we present a precise physics based analytical model for the two-dimensional electron gas density ns in AlGaAs/GaAs high electron mobility transistors. The model is developed by considering the variation of Fermi-level Ef, the first sub-band E₀, the second sub-band E₁, and ns with the applied gate voltage Vg. Taking into account the interdependence between Ef and ns, we have developed an explicit expression for ns in terms of bias voltages. The developed expression for ns is valid in all the regions of device operation, with gate-voltage ranging from below to above the cut-off voltage. The proposed model is in very good agreement with numerical calculations.4 page(s

A Physics-based analytical model for 2DEG charge density in AlGaN/GaN HEMT devices

In this brief, we present a physics-based analytical model for 2-D electron gas density ns in AlGaN/GaN high-electron mobility transistors. The proposed model accounts for the interdependence between Fermi level Ef and ns. The model is developed by considering the variation of Ef, the first subband E₀, the second subband E₁, and ns with applied gate voltage Vg. The proposed model is in very good agreement with numerical calculations.4 page(s

Orchestra: Rapid, collaborative sharing of dynamic data

Conventional data integration techniques employ a “top-down ” design philosophy, starting by assessing requirements and defining a global schema, and then mapping data sources to that schema. This works well if the problem domain is well-understood and relatively static, as with enterprise data. However, it is fundamentally mismatched with the “bottom-up ” model of scientific data sharing, in which new data needs to be rapidly developed, published, and then assessed, filtered, and revised by others. We address the need for bottom-up collaborative data sharing, in which independent researchers or groups with different goals, schemas, and data can share information in the absence of global agreement. Each group independently curates, revises, and extends its data; eventually the groups compare and reconcile their changes, but they are not required to agree. This paper describes our initial design and prototype of the ORCHESTRA system, which focuses on managing disagreement among multiple data representations and instances. Our work represents an important evolution of the concepts of peer-to-peer data sharing [23], which considers revision, disagreement, authority, and intermittent participation. ∗ Work done while an M.S. student at the Univ. of Pennsylvania

Application of Zn/Al layered double hydroxides for the removal of nano-scale plastic debris from aqueous systems

Nano-scale plastic debris (NPDs) are emerging as potential contaminants as they can be easily ingested by aquatic organisms and carry many pollutants in the environment. This study is aimed to remove NPDs from aqueous environment for the first time by using eco-friendly adsorption techniques. Initially, the interaction between NPDs and synthesized Zn-Al layered double hydroxide (LDH) was confirmed by pH titration of Zn-Al LDH against NPDs at varying mass ratio (50:1 to 50:7) and FTIR analysis for both before and after 2 h of contact time. Fast removal was observed in deionized water and synthetic freshwater with maximum sorption capacity (Q(ma)(x)) of 164.49 mg/g,162.62 mg/g, respectively, according to Sips isotherm. Whereas, removal was least in synthetic hard water having a Q(max) value of 53 mg/g. For 2 mM concentration of So(4)(2-) and PO43-, the adsorption capacity significantly decreased to 2%. The removal efficiency was found 100 % at pH 4, while at pH 9, it reached 37 % due to increased competitive binding and destabilization of LDH under alkaline conditions. The process of sorption was spontaneous in different types of water studied. The study reveals that Zn-Al LDH can be used as potential adsorbent for the removal of NPDs from freshwater systems

Effect of the irrigation water type and other environmental parameters on CeO2 nanopesticide-clay colloid interactions

In this work, the stability and aggregation behaviour of CeO2 nanoparticles (NPs) was investigated to predict their fate in the agricultural environment. For this, the aggregation kinetics of CeO2 NPs was studied under varying pH, ionic strength (IS), dissolved organic matter (DOM) and carbonate concentrations in the presence of clay. Furthermore, different types of irrigation water have been used to check the fate of CeO2 nanoparticles (NPs) in complex aqueous matrices. The results show that critical coagulation concentration (CCC) values obtained for CeO2 NPs, i.e. 26.5 mM and 7.9 mM for NaCl and CaCl2 respectively, drastically decreased to 16.2 mM and 1.87 mM in the presence of bentonite clay colloids, which may lead to their deposition within the soil matrix. However, the presence of bicarbonate ions (0.1-2 mM) along with DOM (1-20 mg L-1) may result in their stabilization and co-transport of CeO2 NPs with clay in water bodies having low ionic strength. It was also observed that the negative charge of a bentonite clay suspension was completely reversed with an increase in CeO2 concentration by 37.5 times. The critical charge reversal concentration value was 284.4 mg L-1 in Milli-Q water whereas values were observed to be 680 mg L-1 in synthetic-soft water, followed by natural river water (867 mg L-1) and synthetic-hard water (910 mg L-1). The synergistic effect of temperature and ionic strength was observed on the aggregation behaviour of CeO2 NPs in environmental water samples of varying composition

Varying growth behavior of redox-sensitive nanoparticles on 1:1 and 2:1 clay surfaces: mechanistic insights on preferential toxic ions removal in mono, co and multi-metal contaminated waters

International audienceIn the current study, contrasting growth behaviour of redox sensitive Fe0 nanoparticles (nZVI)was observed on different clay surfaces i.e., 1:1 non-swelling kaolinite (K-nZVI) and 2:1swelling bentonite (B-nZVI). Osmotic swelling of bentonite led to Fe0 nucleation and growthof 5-7 nm size particles in the broadened interlayer spaces. B-nZVI had negative zeta potentialdue to the domination of the surface charge of bentonite clay. Whereas kaolinite has showndominant surface growth of nZVI particles (>24.8±7.4 nm) and positive zeta potential,suggesting domination of Fe0 nanoparticles (nZVI) characteristics. This surface-dependentvariation led to higher and faster removal of oxy-anions with K-nZVI, i.e., chromium andarsenic (87.5 and 157.35 mg/g) than B-nZVI (18.4 and 86.9 mg/g). In comparison, B-nZVI hasshown higher sorption of cations i.e., nickel and cadmium (36 mg/g and 46 mg/g) than K-nZVI(25 and 27 mg/g). XPS and pXRD analysis of reaction precipitates confirmed reductivesorption of chromium, co-precipitation/ complexation of arsenic, electrostatic attraction andcomplexation of nickel and cadmium as major removal mechanisms. Drastically higher totalcontaminant sorption capacities of B-nZVI (327 mg/g) and K-nZVI (372 mg/g) in multicontaminant(Cr+As+Ni+Cd) solutions than individual capacities in mono-ionic solutions wasdue to co-operative effects and newer sites induced via sorption and redox-transformation ofother ionic species. K-nZVI removed chromium and arsenic to below drinking waterpermissible limits whereas B-nZVI succeeded in separating nickel and cadmium to drinkablelevels in groundwater, freshwater, river water, and wastewater samples, emphasizing theirapplicability in high cationic—low anionic and low cationic-higher anionic speciescontaminated waters, respectively

Impact of long-term storage of various redox-sensitive supported nanocomposites on their application in removal of dyes from wastewater: mechanisms delineation through spectroscopic investigations

International audienceFor the prevention of freshwater reservoirs from contamination through industrial effluents, eco-friendly adsorbents with minimal aging impact are required. Here, redox-sensitive nanoscale zero-valent iron(nZVI) particles were supported on four different surfaces with varying bentonite(B)/charcoal(C) ratio to mimic layered and porous surfaces. Different dyes, i.e. rhodamine-B(RB) and methylene blue(MB) were reacted with redox-sensitive supported nZVI composites, and degradation mechanisms were delineated using FT-IR spectroscopic analysis of reaction precipitates. A 300-day exposure to open-air was provided to the composites to comparatively evaluate the impact of aging on their reactivity for dyes in wastewater.Results interpret that dyes removal was a combination of different interfacial chemical processes, i.e., reduction or organic degradation probably through Fenton like processes, along with sorption. These mechanisms were found to be surface dependent, i.e., nZVI on charcoal enriched porous surfaces, degrade dyes through organic degradation while on layered clay surfaces, MB gets removed through reduction with limited and slower RB removal. Nanocomposites show a minimal impact of aging with removal capacities >100 mg/g for BC-1/3-nZVI and C-nZVI for MB and 50-75 mg/g for RB with significant removal in wastewater. Overall, the study concludes C-nZVI and novel BC-1/3-nZVI as two efficient dye adsorbents with minimal aging impact