Ion-acoustic solitary waves in e-p-i plasmas with (r,q)-distributed electrons and kappa-distributed positrons

In this paper, we have studied the propagation of non-linear ion-acoustic waves in a plasma comprising of (r, q) -distributed electrons and kappa-distributed positrons. We have investigated the effect of complete electron distribution profile on the propagation of small, as well as arbitrary, amplitude solitons (via pseudopotential technique) by using generalized (r, q) distribution, which exhibits a spiky and flat top nature at low energies and a super-thermal tail at high energies. Interestingly, for negative values of r , solitons are formed with both polarities, positive (compressive) and negative (rarefactive), separately within a small amplitude limit and exist simultaneously in an arbitrary amplitude limit. We also found that the propagation of solitons has been affected by the change in parameters r , q , positron concentration, and electron to positron temperature ratio. The results presented in this study add to the fundamental understanding of the complete profile of the electron distribution function, high- and low-energy parts, and in the formation of compressive and rarefactive small and finite amplitude solitons in both space and astrophysical plasmas.     

Identification of novel inhibitory candidates against two major Flavivirus pathogens via CADD protocols: in silico analysis of phytochemical binding,reactivity, and pharmacokinetics against NS5 from ZIKV and DENV

Structural Chemistry - Zika and dengue virus are flaviviruses which with the passage of time have become a serious challenge affecting millions of people around the world. To lessen the impact of...     

Fabrication of Highly Anisotropic and Interconnected Porous Scaffolds to Promote Preosteoblast Proliferation for Bone Tissue Engineering

Mimicking the complex structure of natural bone remains a challenge for bone tissue scaffolds.In this study,a novel processing strategy was developed to prepare the bone-like scaffolds that are featured by highly oriented and fully interconnected pores.This type of biomimetic scaffolds was evolved from solid phase stretching of immiscible polycaprolactone(PCL)/poly(ethylene oxide)(PEO)blends with co-continuous structure and the pore morphology was inherited from selective extraction of water soluble PEO phase.The pore anisotropy was readily tuned by varying the stretching strain without loss of interconnectivity.Significant promotion in preosteoblast proliferation,alkaline phosphatase activity and osteogenic gene expression was observed in the oriented porous scaffolds compared to the isotropic porous counterpart.The oriented architecture provided a topographical cue for aligned growth of preosteoblasts,which activated the Wnt/β-catenin signaling pathway.The proposed strategy enriches the toolbox for the scaffold design and fabrication for bone tissue engineering.     

Insights into the inhibitory potential of selective phytochemicals against Mpro of 2019-nCoV: a computer-aided study

Structural Chemistry - At the end of December 2019, a novel strain of coronavirus, given the name of 2019-nCoV, emerged for exhibiting symptoms of severe acute respiratory syndrome. The virus is...     

The influence of dodecylamine hydrochloride on the dissolution kinetics of heat-treated hydroxyapatite samples

The influence of dodecylamine hydrochloride (DAC) on the dissolution rate behavior of hydroxyapatite (HAP) samples prepared by digestion at 100°C and heated to various temperatures was investigated. The dissolution rates of HAP samples heated to temperatures of 300, 500, 750, 900, 1000, and 1200°C were determined at various levels of DAC in an acetate buffer having a pH of 4.50 and an ionic strength of 0.10. DAC adsorption isotherms for these different HAP samples and the specific surface areas were also determined. The initial dissolution rates (IDR) for all preparations generally decreased with increasing DAC levels with an approximately inverse relationship between IDR and DAC adsorption. For HAP samples heated at 1000°C and higher, the dissolution rates at 3.0 mM DAC were completely inhibited, while for samples heated at 900°C or less, there was a significant residual IDR at 3.0 mM DAC. This residual rate was approximately 20% of the zero DAC rate for all samples treated between 300 and 900°C. These results are in agreement with the concept that HAP prepared by precipitation and digestion at 100°C has two or more kinds of sites for dissolution and that heat treatment at around 1000°C or greater causes the elimination of one or more of these sites.     

Variation in isotopic composition of precipitation with identification of vapor source using deuterium excess as tool

Journal of Radioanalytical and Nuclear Chemistry - The stable isotopic contents of precipitation and deuterium excess (d-excess) data justified the hypothesis that two distinct vapor sources are...     

Equilibrium,kinetic and thermodynamic biosorption studies of Hg(II) on red algal biomass of Porphyridium cruentum

Among a variety of microbial materials employed for biosorption, algae have added advantages of non-toxic and autotrophic nature. In this study, biosorption of Hg(II) was studied with red algal biomass of Porphyridium cruentum. The parameters affecting biosorption such as dosage of biosorbent, pH, contact time, initial metal concentration, temperature and effect of foreign metal cations in binary system were evaluated. Kinetic data were described with the help of pseudo-first-order and pseudo-second-order kinetic models. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models were applied to adsorption equilibrium data. According to the results, the maximum removal capacity (q_max) was 2.62?mg/g observed at pH 7 with 0.25?g/L of biosorbent dosage for Hg(II) solution containing 10?mg/L of metal ions. The Langmuir isotherm model fits best to the adsorption data while the kinetic data followed the pseudo-second-order model. Thermodynamics studies showed that the biosorption process of Hg(II) on P. cruentum was exothermic in nature.