Phosphorylation of sarcoplasmic and myofibrillar proteins in three ovine muscles during postmortem ageing

This study aimed to examine changes in phosphorylation of sarcoplasmic and myofibrillar proteins from longissimus lumborum,semitendinosus,and psoas major muscles during postmortem ageing for 5 d.These sarcoplasmic and myofibrillar proteins were separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and stained with phosphorous and protein specific stains.Myofibril fragmentation index,pH,the content of lactic acid and the relative activity of μ-calpain in three ovine muscles were measured.These results showed that the relative phosphorylation level of sarcoplasmic and myofibrillar proteins of psoas major muscle were lower compared with longissimus lumborum and semitendinosus muscles(P<0.05).The pH of psoas major muscle was the lowest at 0.5 h postmortem,and the highest after 12 h postmortem(P<0.05).In addition,the relative activity of μ-calpain was higher within 5 d postmortem and myofibril fragmentation index was higher after 1 d postmortem in psoas major muscle than those of longissimus lumborum and semitendinosus muscles(P<0.05).The sarcoplasmic protein phosphorylation may regulate the rate of pH decline to influence the μ-calpain activity and then proteolysis of proteins consequently.This study gives a new perspective of the mechanism of postmortem meat tenderization.

Insights into the multiple applications of modified polyacrylamide as oilfield corrosion inhibitor and water phase tackifier

In order to obtain a multifunctional oilfield agent with both corrosion inhibition and oil displacement functions,a polymer with benzene ring structures is synthesized based on polyacrylamide(PAM)and used as inhibitor for the first time.Methods including electrochemistry,weight loss and theoretical calculations are used to study the inhibition effect for P110 steel in 1.0 M HCl.The experimental results show that the modified polymer poly-(Z)-N-benzylidenepropionamide(PBAM)has excellent inhibition effects,and the maximum efficiency can reach 90.62%in impedance spectroscopy tests.The benzene ring structure added in the modified polymer providesπelectrons for the adsorption of inhibitor on metal surface,strengthens the adsorption,and thus brings a better corrosion inhibition effect.In addition to the corrosion inhibition performance,the viscosity-increasing effect of PBAM is evaluated.The results show that the addition of benzene ring not only enhances the corrosion inhibition effect,but also brings temperature resistance to the polymer.However,the salt tolerance of the polymer is affected,the synthesized PBAM which viscosity can above 500 m Pa s at 140℃ is suitable for high temperature and low salinity environment.The modified polyacrylamide has satisfactory corrosion inhibition and oil displacement performance,which provides a new idea for the development of oilfield chemistry.

Effect of titin phosphorylation on degradation of titin from skeletal muscles

The degradation of titin could make the myofibrillar fragmentation to improve meat tenderization during postmortem.This study aimed to investigate effect of phosphorylation on titin degradation.Protein kinase A(PKA)and alkaline phosphatase(AP)were added to crude titin extracted from ovine longissimus lumborum(LL)muscles.Phosphorylated/dephosphorylated titin were incubated withμ-calpain at 4℃ for 2 days.Results showed titin in AP group started degradation earlier than that in PKA and control groups.There were 20,16 and 12 phosphorylated sites identified by iTRAQ in the PKA,control and AP group,respectively.3D structure of dephosphorylated titin fragment was simulated and its molecular dynamics trajectory analysis was performed using Discovery StudioTM.The dihedral angle in AP group was less and the dephosphorylated fragment had a higher kinetic energy and total energy.We suggested that changes caused by AP treatment might make titin unstable,which easily degraded byμ-calpain.

Advances in the functional study of glutamine synthetase in plant abiotic stress tolerance response

Plant glutamine synthetase(GS,EC6.3.1.2)catalyzes the synthesis of glutamine from glutamate and ammonium ions and acts as a key enzyme in the nitrogen metabolic pathway in organisms.Nitrogen is an essential element for plant growth and development and plays an important role in crop yield and quality formation.Therefore,GS is crucial in many physiological processes in plants.Currently,nitrogen regulation by GS in plants is well-studied in terms of its effect on plant growth and development.This article reviews the regulatory role of plant GS and its molecular mechanism in mitigating stress injury,such as low or high temperature,salinity,drought and oxidation.The function of plant GS in stress tolerance response is focused.The review aims to provide a reference for the utilization of plant GS in crop stress tolerance breeding.

Nitrogen and Boron Co-Doped Carbon Nanotubes Embedded with Nickel Nanoparticles as Highly Efficient Electromagnetic Wave Absorbing Materials

Due to the limitations of impedance matching and attenuation matching,carbon nanotubes(CNTs)employed alone have a weak capacity to attenuate electromagnetic wave(EMW)energy.In this work,B and N co-doped CNTs with embedded Ni nanoparticles(Ni@BNCNTs)are fabricated via an in situ doping method.Compared with a sample without B doping,Ni@BNCNTs demonstrate a superior EMW absorption performance,with all minimum reflection loss values below−20 dB,even at a matching thickness of 1.5 mm.The experimental and theoretical calculation results demonstrate that B doping increases conduction and polarization relaxation losses,as well as the impedance matching characteristic,which is responsible for the enhanced EMW absorption performance of Ni@BNCNTs.

Numerical study on the dependence of ZnO thin-film transistor characteristics on grain boundary position

The dependence of transistor characteristics on grain boundary （GB） position in short-channel ZnO thin film transistors （TFTs） has been investigated using two-dimensional numerical simulations. To simulate the device accurately, both tail states and deep-level states are taken into consideration. It is shown that both the transfer and output characteristics of ZnO TFTs change dramatically with varying GB position, which is different from polycrystalline Si （poly-Si） TFTs. By analysing the mechanism of the carrier transportation in the device, it is revealed that the dependence is derived from the degrees of carrier concentration descent and mobility variation with CB position.

Monte Carlo study of the magnetic properties of spin liquid compound NiGa_2S_4

The magnetic properties of two-dimensional antiferromagnet NiGa2S4 have attracted much attention and yet some problems are far from being solved. We investigate the magnetic properties of NiGa2S4 by Monte Carlo simulations. A new spin-interacting model is proposed to describe the system, and the specific heat together with the doping effect of nonmagnetic impurity is studied by simulations. The double peaks of the specific heat as well as other behaviors are well reproduced. We also compare our results with those of other models, and the underlying physics is discussed.

Pyridine-regulated Sb@InSbS_(3)ultrafine nanoplates as high-capacity and long-cycle anodes for sodium-ion batteries

Sb-based materials exhibit considerable potential for sodium-ion storage owing to their high theoretica capacities.However,the bulk properties of Sb-based materials always result in poor cycling and rate performances.To overcome these issues,pyridine-regulated Sb@InSbS_(3)ultrafine nanoplates loaded on reduced graphene oxides(Sb@InSbS_(3)@rGO)were designed and synthesized.During the synthesis process,pyridine was initially adopted to coordinate with In^(3+),and uniformly dispersed In_(2)S_(3)ultrafine nanoplates on reduced graphene oxide were generated after sulfidation.Next,partial In^(3+)was exchanged with Sb^(3+),and Sb@InSbS_(3)@rGO was obtained by using the subsequent annealing method.The unique structure of Sb@InSbS_(3)@rGO effectively shortened the transfer path of sodium ions and electrons and provided a high pseudocapacitance.As the anode in sodium-ion batteries,the Sb@InSbS_(3)@rGO electrode demonstrated a significantly higher reversible capacity better stability(445 m Ah·g^(-1)at 0.1 A·g^(-1)after 200 cycles and 212 mAh·g^(-1)at 2 A·g^(-1)after 1200 cycles),and superior rate(210 mAh·g^(-1)at 6.4 A·g^(-1))than the electrode without pyridine(355 mAh·g-1at 0.1 A·g-1after 55 cycles and 109 mAh·g^(-1)at 2 A·g^(-1)after 770 cycles)Furthermore,full cells were assembled by using the Sb@InSbS_(3)@rGO as anode and Na_(3)V_(2)(PO_(4))_(3)as cathode which demonstrated good cycling and rate performances and exhibited promising application prospects.These results indicate that adjusting the microstructure of electrode materials through coordination balance is A·good strategy for obtaining high-capacity,high-rate,and longcycle sodium storage performances.

Effects of rebinding rate and asymmetry in unbinding rate on cargo transport by multiple kinesin motors

Many intracellular transports are performed by multiple molecular motors in a cooperative manner.Here,we use stochastic simulations to study the cooperative transport by multiple kinesin motors,focusing mainly on effects of the form of unbinding rate versus force and the rebinding rate of single motors on the cooperative transport.We consider two forms of the unbinding rate.One is the symmetric form with respect to the force direction,which is obtained according to Kramers theory.The other is the asymmetric form,which is obtained from the prior studies for the single kinesin motor.With the asymmetric form the simulated results of both velocity and run length of the cooperative transport by two identical motors and those by a kinesin-1 motor and a kinesin-2 motor are in quantitative agreement with the available experimental data,whereas with the symmetric form the simulated results are inconsistent with the experimental data.For the cooperative transport by a faster motor and a much slower motor,the asymmetric form can give both larger velocity and longer run length than the symmetric form,giving an explanation for why kinesin adopts the asymmetric form of the unbinding rate rather than the symmetric form.For the cooperative transport by two identical motors,while the velocity is nearly independent of the rebinding rate,the run length increases linearly with the rebinding rate.For the cooperative transport by two different motors,the increase of the rebinding rate of one motor also enhances the run length of the cooperative transport.The dynamics of transport by N(N=3,4,5,6,7 and 8)motors is also studied.

Gluon Saturation Model with Geometric Scaling for Net-Baryon Distributions in Relativistic Heavy Ion Collisions

The net-baryon number is essentially transported by valence quarks that probe the saturation regime in the target by multiple scattering. The net-baryon distributions, nuclear stopping power and gluon saturation features in the SPS and RHIC energy regions are investigated by taking advantage of the gluon saturation model with geometric scaling. Predications are made for the net-baryon rapidity distributions, mean rapidity loss and gluon saturation features in central Pb ＋ Pb collisions at LHC.

Large family of two-dimensional ferroelectric metals discovered via machine learning

Ferroelectricity and metallicity are usually believed not to coexist because conducting electrons would screen out static internal electric fields.In 1965,Anderson and Blount proposed the concept of"ferroelectric metal",however,it is only until recently that very rare ferroelectric metals were reported.Here,by combining high-throughput ab initio calculations and data-driven machine learning method with new electronic orbital based descriptors,we systematically investigated a large family(2964)of two-dimensional(2D)bimetal phosphates,and discovered 60 stable ferroelectrics with out-of-plane polarization,including 16 ferroelectric metals and 44 ferroelectric semiconductors that contain seven multiferroics.The ferroelectricity origins from spontaneous symmetry breaking induced by the opposite displacements of bimetal atoms,and the full-d-orbital coinage metal elements cause larger displacements and polarization than other elements.For 2D ferroelectric metals,the odd electrons per unit cell without spin polarization may lead to a half-filled energy band around Fermi level and is responsible for the metallicity.It is revealed that the conducting electrons mainly move on a single-side surface of the 2D layer,while both the ionic and electric contributions to polarization come from the other side and are vertical to the above layer,thereby causing the coexistence of metallicity and ferroelectricity.Van der Waals heterostructures based on ferroelectric metals may enable the change of Schottky barrier height or the Schottky-Ohmic contact type and induce a dramatic change of their vertical transport properties.Our work greatly expands the family of 2D ferroelectric metals and will spur further exploration of 2D ferroelectric metals.

Dynamical Properties of a Diluted Dipolar-Interaction Heisenberg Spin Glass

Up to now the chirality is seldom studied in the diluted spin glass although many investigations have been performed on the site-ordered Edwards-Anderson model. By simulation, we investigate the dynamicaJ properties of both the spin-glass and the chiral-glass phases in a diluted dipolar system, which was manifested to have a spin-glass transition by recent numerical study. By scaling we find that both phases have the same aging behavior and closer aging parameterμ. Similarly, the domains grow in the same way and both phases have a closer barrier exponent g2. It means that both the spins and the chirality have the same dynamical properties and they may freeze at the same temperature.

Ultrathin Co（Ni）-doped MoS2 nanosheets as catalytic promoters enabling efficient solar hydrogen production

The design of efficient artificial photosynthetic systems that harvest solar energy to drive the hydrogen evolution reaction via water reduction is of great importance from both the theoretical and practical viewpoints. Integrating appropriate co-catalyst promoters with strong light absorbing materials represents an ideal strategy to enhance the conversion efficiency of solar energy in hydrogen production. Herein, we report, for the first time, the synthesis of a class of unique hybrid structures consisting of ultrathin Co（Ni）-doped MoS2 nanosheets （co-catalyst promoter） intimately grown on semiconductor CdS nanorods （light absorber）. The as-synthesized one-dimensional CdS@doped-MoS2 heterostructures exhibited very high photocatalytic activity （with a quantum yield of 17.3%） and stability towards H2 evolution from the photoreduction of water. Theoretical calculations revealed that Ni doping can increase the number of uncoordinated atoms at the edge sites of MoS2 nanosheets to promote electron transfer across the CdS/MoS2 interfaces as well as hydrogen reduction, leading to an efficient H2 evolution reaction.

Graphene/N-doped amorphous carbon sheet for hydrogen evolution

Dear Editors, Hydrogen is a promising candidate for use in the future as an alternative to traditional petroleum fuels. Electrochemi- cal water splitting is an efficient way to produce hydrogen. It is well known that platinum and other precious metals have high HER efficiency. The high cost and scarcity of these precious metals, however, limit their applicability to large-scale hydrogen production. Therefore, considerable attention has been focused recently on exploitation of non-precious catalysts.

Traveling Wave Solutions to the Three-Dimensional Nonlinear Viscoelastic System

In this paper, we establish the existence of traveling wave solutions to the nonlinear three-dimensional viscoelastic system exhibiting long range memory. Under certain hypotheses, if the speed of propagation is between the speeds determined by the equilibrium and instantaneous elastic tensors, then the system has nontrivial trav- eling wave solutions. Moreover, the system has only trivial traveling wave solution in some cases.