Postaragonite phases of CaCO3 at lower mantle pressures

The stability, structure and properties of carbonate minerals at lower mantle conditions has significant impact on our understanding of the global carbon cycle and the composition of the interior of the Earth. In recent years, there has been significant interest in the behavior of carbonates at lower mantle conditions, specifically in their carbon hybridization, which has relevance for the storage of carbon within the deep mantle. Using high-pressure synchrotron X-ray diffraction in a diamond anvil cell coupled with direct laser heating of CaCO3 using a CO2 laser, we identify a crystalline phase of the material above 40 GPa − corresponding to a lower mantle depth of around 1,000 km − which has first been predicted by ab initio structure predictions. The observed sp2 carbon hybridized species at 40 GPa is monoclinic with P21/c symmetry and is stable up to 50 GPa, above which it transforms into a structure which cannot be indexed by existing known phases. A combination of ab initio random structure search (AIRSS) and quasi-harmonic approximation (QHA) calculations are used to re-explore the relative phase stabilities of the rich phase diagram of CaCO3. Nudged elastic band (NEB) calculations are used to investigate the reaction mechanisms between relevant crystal phases of CaCO3 and we postulate that the mineral is capable of undergoing sp2-sp3 hybridization change purely in the P21/c structure − forgoing the accepted post-aragonite Pmmn structure

Fabrication of Pd NPs on pectin-modified Fe3O4 NPs: A magnetically retrievable nanocatalyst for efficient C-C and C-N cross coupling reactions and an investigation of its cardiovascular protective effects

The present report represents the synthesis of a novel Pd NPs immobilized over a natural polysaccharide (pectin) coated Fe3O4 magnetic nanocomposite material (Fe3O4@pectin/Pd) for investigating the cardiovascular protective effects. The biomolecular functionalization not only stabilizes the ferrite nanoparticles from agglomeration but also provides an environment for the biogenic reduction of Pd2+ ions. This protocol is a promising breakthrough for the synthesis of a quasi-heterogeneous catalyst, a bridge between heterogeneous and homogeneous medium. The structure, morphology and physicochemical properties of the material were characterized utilizing various analytical techniques like FT-IR FE-SEM, TEM, VSM, EDX-elemental mapping, ICP, EDX and XPS. The catalyst showed excellent reactivity in C-C and C-N cross coupling reactions via Suzuki and Buchwald-Hartwig reactions respectively. An array of different biphenyls and aryl amines were then procured by reactions of various aryl halides with phenyl boronic acid or secondary amines over the catalyst affording good to excellent yields. The catalyst was easily recoverable using an external magnet and thereafter recycled for several trials with insignificant palladium leaching or loss in catalytic performance. To investigate the cardiovascular protective activities of catalyst, the MTT assay was done on Human Aortic Endothelial Cells (HAEC), Human Coronary Artery Endothelial Cells (HCAEC), and Human Pulmonary Artery Endothelial Cells (HPAEC) cell lines. Nanocatalyst-treated cell cutlers significantly (p <= 0.01) decreased the caspase-3 activity, and DNA fragmentation. It raised the cell viability and mitochondrial membrane potential in the high concentration of Mitoxantrone-treated HAEC, HCAEC, and HPAEC cells. According to the above findings, nanocatalyst can be administrated as a cardiovascular protective drug for the treatment of cardiovascular diseases after approving in the clinical trial studies in humans. (C) 2020 Published by Elsevier B.V

Static and vibration analysis of functionally graded beams using refined shear deformation theory

Static and vibration analysis of functionally graded beams using refined shear deformation theory is presented. The developed theory, which does not require shear correction factor, accounts for shear deformation effect and coupling coming from the material anisotropy. Governing equations of motion are derived from the Hamilton's principle. The resulting coupling is referred to as triply coupled axial-flexural response. A two-noded Hermite-cubic element with five degree-of-freedom per node is developed to solve the problem. Numerical results are obtained for functionally graded beams with simply-supported, cantilever-free and clamped-clamped boundary conditions to investigate effects of the power-law exponent and modulus ratio on the displacements, natural frequencies and corresponding mode shapes

Corrigendum to �The effect of green-coffee extract supplementation on obesity: A systematic review and dose-response meta-analysis of randomized controlled trials� Phytomedicine Volume 63 October 2019 Article 153018 (Phytomedicine (2019) 63, (S0944711319301849), (10.1016/j.phymed.2019.153018))

The authors regret that the original version of this Article (https://doi.org/10.1016/j.phymed.2019.153018I) contained an error about in data extraction for Dellalibera O et al. 2006 in body weight section. This article reported that green coffee reduces body Wight -2.52 kg but we mention it 2.52. We edited this mistake and revised results. According to new results Green-Coffee Extract supplementation significantly reduced body weight (WMD: -0.94 kg, 95 CI: -1.73, -0.16, p = 0.019). The authors would like to apologise for any inconvenience caused (Figure 1). © 2019 Elsevier Gmb

Dihexyl-Substituted Poly(3,4-Propylenedioxythiophene) as a Dual Ionic and Electronic Conductive Cathode Binder for Lithium-Ion Batteries

The polymer binders used in most lithium-ion batteries (LIBs) serve only a structural role, but there are exciting opportunities to increase performance by using polymers with combined electronic and ionic conductivity. To this end, here we examine dihexyl-substituted poly(3,4-propylenedioxythiophene) (PProDOT-Hx₂) as an electrochemically stable π-conjugated polymer that becomes electrically conductive (up to 0.1 S cm⁻¹) upon electrochemical doping in the potential range of 3.2 to 4.5 V (vs Li/Li⁺). Because this family of polymers is easy to functionalize, can be effectively fabricated into electrodes, and shows mixed electronic and ionic conductivity, PProDOT-Hx₂ shows promise for replacing the insulating polyvinylidene fluoride (PVDF) commonly used in commercial LIBs. A combined experimental and theoretical study is presented here to establish the fundamental mixed ionic and electronic conductivity of PProDOT-Hx₂. Electrochemical kinetics and electron spin resonance are first used to verify that the polymer can be readily electrochemically doped and is chemically stable in a potential range of interest for most cathode materials. A novel impedance method is then used to directly follow the evolution of both the electronic and ionic conductivity as a function of potential. Both values increase with electrochemical doping and stay high across the potential range of interest. A combination of optical ellipsometry and grazing incidence wide angle X-ray scattering is used to characterize both solvent swelling and structural changes that occur during electrochemical doping. These experimental results are used to calibrate molecular dynamics simulations, which show improved ionic conductivity upon solvent swelling. Simulations further attribute the improved ionic conductivity of PProDOT-Hx₂ to its open morphology and the increased solvation is possible because of the oxygen-containing propylenedioxythiophene backbone. Finally, the performance of PProDOT-Hx₂ as a conductive binder for the well-known cathode LiNi_(0.8)Co_(0.15)Al_(0.05)O₂ relative to PVDF is presented. PProDOT-Hx₂-based cells display a fivefold increase in capacity at high rates of discharge compared to PVDF-based electrodes at high rates and also show improved long-term cycling stability. The increased rate capability and cycling stability demonstrate the benefits of using binders such as PProDOT-Hx₂, which show good electronic and ionic conductivity, combined with electrochemical stability over the potential range for standard cathode operation

Propagation of RML Prions in Mice Expressing PrP Devoid of GPI Anchor Leads to Formation of a Novel, Stable Prion Strain

PrPC, a host protein which in prion-infected animals is converted to PrPSc, is linked to the cell membrane by a GPI anchor. Mice expressing PrPC without GPI anchor (tgGPI- mice), are susceptible to prion infection but accumulate anchorless PrPSc extra-, rather than intracellularly. We investigated whether tgGPI− mice could faithfully propagate prion strains despite the deviant structure and location of anchorless PrPSc. We found that RML and ME7, but not 22L prions propagated in tgGPI− brain developed novel cell tropisms, as determined by the Cell Panel Assay (CPA). Surprisingly, the levels of proteinase K-resistant PrPSc (PrPres) in RML- or ME7-infected tgGPI− brain were 25–50 times higher than in wild-type brain. When returned to wild-type brain, ME7 prions recovered their original properties, however RML prions had given rise to a novel prion strain, designated SFL, which remained unchanged even after three passages in wild-type mice. Because both RML PrPSc and SFL PrPSc are stably propagated in wild-type mice we propose that the two conformations are separated by a high activation energy barrier which is abrogated in tgGPI− mice

A novel matrix approach to fractional finite difference for solving models based on nonlinear fractional delay differential equations

Many real-life phenomena in physics, engineering, biology, medicine, economics, etc. can be modeled by fractional delay differential equations and having in mind that these modeling interpret phenomena better, they are noticed by researchers, engineers, and mathematicians. In this paper the method of fractional finite differences has been presented and used for numerical solution of such models and used for solving a number of famous fractional order version of models such as the fractional order version of Hutchinson model is related to rate of population growth, the fractional order version of Verhulst Pearl model is related to the impact of a specific factor on the changes of population in an area model, fractional order version of the negative impact of population growth in a specific time and model of fractional order version of the four years life cycle of a population of lemmings. The proposed method besides being simple is so exact which is sensible in the solved problems