[The progress on post-exposure prophylaxis of tetanus immunological preparation in adults].

The tetanus has been eliminated in the pregnancy women and newborns in China. However, there is a gap for adult tetanus immunization, and the risk of tetanus infection cannot be ignored. In order to clearly understand the effect of the tetanus to human beings and the current use of tetanus immunological preparation for adult post-exposure prophylaxis, the incidence of the tetanus, the use status of tetanus immunological preparation and recommendations for post-exposure prophylaxis at home and abroad were reviewed and summarized, which may provide academic evidence for post-exposure prophylaxis procedures and use of tetanus immunological preparation.

Establishment and characterization of a chimeric infectious cDNA clone of classical swine fever virus.

Classical swine fever virus (CSFV) causes a highly contagious disease among swine that has an important economic impact worldwide. There are two important CSFV strains in China, Shimen and hog cholera lapinized virus (HCLV). Shimen strain is highly virulent while HCLV, also referred to as C-strain, is a live attenuated vaccine strain considered to be one of the most effective and safest live vaccines. In this study, a chimeric infectious cDNA clone of CSFV named pT7SM-c was engineered by replacing the E(rns) genomic region of an infectious clone of CSFV Shimen strain, pT7SM, with the same region obtained from HCLV. RNA transcripts of pT7SM-c containing an engineered EcoRI site that served as a genetic marker were directly infectious in PK15 cells. The rescued virus vT7SM-c showed similar growth kinetics and cytopathic effect with the parental virus vT7SM in the cells. The chimeric infectious cDNA clone can be used as a practical tool for further studying of the virulence, protein function and pathogenesis of CSFV through genetic manipulation.

Formation of Li3O4 nano particles in the discharge products of non-aqueous lithium-oxygen batteries leads to lower charge overvoltage.

Density functional theory calculations are made for bulk thermodynamic properties and surface energies of Li2O2, a primary discharge product, and Li3O4, a possible byproduct in the discharge products, of the non-aqueous lithium-oxygen batteries. Results show that the standard formation Gibbs free energy of bulk Li3O4 is marginally higher than that of Li2O2, but the surface energy of Li3O4 is much lower. Low surface energy results in both lowered nucleation energy and formation Gibbs free energy in the nanometer regime, allowing the Li3O4 nano particles to nucleate ahead of Li2O2 during the discharge process and to exist stably when particle sizes are smaller than about 40 nm. The scanning transmission electron microscopy (STEM) image of Li3O4 crystals is simulated and compared with the measured STEM image of the discharge product particles. The consistency between the simulated and measured STEM images suggests that the Li3O4 phase can exist stably as a discharge product. The energy profile of the oxygen evolution reaction (OER) occurring on the most abundant surfaces of Li3O4 is also calculated. The predicted overpotential for the OER on the {0001} surface (0.30 V) shows a good agreement with experimental data. The presence of more electronically conductive Li3O4 nano particles in the primary discharge product Li2O2 tends to decrease the charge overvoltage of the batteries, explaining why the lower voltage area (<3.5 V) was widely observed during the charging of the batteries. An increase in the oxygen pressure or a decrease in temperature enhances the stability of the Li3O4 phase and increase the proportion of the Li3O4 phase in the discharge products, consequently leading to a lower overall charge overvoltage.

Determination of the mass-transport properties of vanadium ions through the porous electrodes of vanadium redox flow batteries.

This work is concerned with the determination of two critical constitutive properties for mass transport of ions through porous electrodes saturated with a liquid electrolyte solution. One is the effective diffusivity that is required to model the mass transport at the representative element volume (REV) level of porous electrodes in the framework of Darcy's law, while the other is the pore-level mass-transfer coefficient for modeling the mass transport from the REV level to the solid surfaces of pores induced by redox reactions. Based on the theoretical framework of mass transport through the electrodes of vanadium redox flow batteries (VRFBs), unique experimental setups for electrochemically determining the two transport properties by measuring limiting current densities are devised. The effective diffusivity and the pore-level mass-transfer coefficient through the porous electrode made of graphite felt, a typical material for VRFB electrodes, are measured at different electrolyte flow rates. The correlation equations, respectively, for the effective diffusivity and the pore-level mass-transfer coefficient are finally proposed based on the experimental data.

Synthesis, antiproliferative and 4D-QSAR studies of thiadiazole derivatives bearing acrylamide moiety as EGFR inhibitors.

As a target for clinical anti-cancer treatment, epidermal growth factor receptor (EGFR) exhibits its over-expression on various tumour cells and is associated with the development of a variety of human cancers. Herein, we described the synthesis, antiproliferative activity assay and 4D-QSAR studies of thiadiazole derivatives bearing acrylamide moiety as EGFR inhibitors. Compared with Gefitinib, some of the target compounds have excellent antiproliferative activities against EGFR-expressed A431 cell line. The robust and reliable 4D-QSAR was constructed using comparative distribution detection algorithm, ordered predictors selection and genetic algorithm method, and the following acceptable statistics are shown: r2 = 0.82, Q2LOO = 0.67, Q2LMO = 0.61, r2Pred = 0.78.

Manipulation of Electrode Composition for Effective Water Management in Fuel Cells Fed with an Electrically Rechargeable Liquid Fuel.

The liquid fuel cell, with its high energy density and ease of fuel handling, has attracted great attention worldwide. However, its real application is still being greatly hindered by its limited power density. Hence, the recently proposed and demonstrated fuel cell, using an electrically rechargeable liquid fuel (e-fuel), is believed to be a candidate with great potential due to its significant performance advancement. Unlike the conventional alcoholic liquid fuels, the e-fuel possesses excellent reactivity, even on carbon-based materials, which therefore allows the e-fuel cell to achieve superior performance without any noble metal catalysts. However, it is found that, during the cell operation, the water generated at the cathode following the oxygen reduction reaction could lead to a water flooding problem and further limit the cell performance. To address this issue, in this work, by manipulating the cathode composition, a blended binder cathode using both Nafion and polytetrafluoroethylene as binding agents is fabricated and demonstrated its superiority in the fuel cell to achieve an enhanced water management and cell performance. Furthermore, using the developed cathode, a fuel cell stack is designed and fabricated to power a 3D-printed toy car, presenting this system as a promising device feasible for future study and real applications.

[Review on immunogenicity, safety and social value of combined vaccines for children used both at home and abroad].

Combined vaccines contain two or more antigens. Research suggested that combined vaccines could prevent multi diseases and reduce the frequency of vaccination. This article focus on combined vaccines for children used both at home and abroad, such as diphtheria-pertussis-tetanus vaccine (DTaP), measles-rubella-mumps vaccine (MMR), etc. and summarizes their immunogenicity, safety and social values, including benefits to families, vaccination workers and health services, to provide evidence for promoting the research, development and use of combined vaccines in China. We found that combined vaccines can not only ensure the immunogenicity and safety, but also give convenient and lower cost vaccination to families, and using combined vaccines can improve the work efficiency of vaccination workers, reduce the impact of the epidemic on immunization services and improve vaccination coverage and timeliness. At present, the promotion of combined vaccines in China is restricted by many technical bottlenecks, high prices, and low awareness among people. It is recommended that research on the safety, effectiveness and health economics of combined vaccines should be strengthened, and the value of combined vaccines should be scientifically evaluated; the public's awareness and trust in combined vaccines should be enhanced, as well as the development and application of multi-linked multivalent vaccines should be promoted. The government should improve regulations to assist the development and application of combined vaccines.

Synthesis and receptor dependent 4D-QSAR studies of 4,5-dihydro-1,3,4-oxadiazole derivatives targeting cannabinoid receptor.

Cannabinoid receptor has been shown to be overexpressed in various types of cancers, especially non-small cell lung cancer. As a result, it could be used as novel target for anticancer treatments. Because receptor-dependent 4D-QSAR generates conformational ensemble profiles of compounds by molecular dynamics simulations at the binding site of the enzyme, this work describes the synthesis, biological activity evaluation and 4D-QSAR studies of 4,5-dihydro-1,3,4-oxadiazole derivatives targeting cannabinoid receptor. Compared with WIN55,212-2, compound 5 f showed the best antiproliferative activity. The receptor-dependent 4D-QSAR model was generated by multiple linear regression method using QSARINS. Leave-n-out cross-validation and chemical applicability domain were performed to analyse the independent test set and to verify the robustness of the model. The best 4D-QSAR model showed the following statistics: r2 = 0.8487, Q2LOO = 0.7667, Q2LNO = 0.7524, and r2Pred = 0.8358.

[Development and outlook on human challenge trial of vaccine].

Human challenge trial (HCT) is a test in which human volunteers are intentionally infected with pathogens in order to evaluate the efficacy of candidate preventive or therapeutic drugs. During the COVID-19 pandemic, the HCT of vaccines has aroused people's attention due to its significant advantages over clinical trial. This paper introduces the concept, development and application of HCT, the advantages and limitations of HCT for vaccine evaluation, and the consideration of future HCT of COVID-19 vaccine in China.

[Hesitancy of parents towards vaccines in national immunization program in three regions in China: a cross-sectional study].

Objective: To investigate the incidence and determinants of vaccine hesitancy towards national immunization program in China and understand the current status of parents' hesitancy to different vaccines used in national immunization program. Methods: A cross-sectional survey was conducted in Beijing, Sichuan and Gansu. The methods of proportional probability sampling and convenience sampling were used to select the eligible study subjects for questionnaire surveys. Results: A total of 3 592 parents were enrolled in the study, in whom 38.22% fully accepted all the vaccines, 59.35% agreed to let their children to receive all the vaccines but showed slight concern, and 2.42% had hesitancy to the vaccines. The vaccine with the most hesitancy was polio vaccine (0.89%), followed by diphtheria pertussis tetanus vaccine (0.70%) and hepatitis A vaccine (0.64%). The dominant reason for vaccine hesitancy was the risk-benefit perception of vaccination (31.03%), followed by the low awareness of the parents (21.84%) and the inconvenience caused by distance and time (21.84%). Conclusions: The incidence of vaccine hesitancy towards national immunization program was low in parents in China, but over 50% of the parents showed concern to the vaccines. It is essential to improve the service quality of national immunization program and strengthen the health education about the vaccination to reduce the incidence of vaccine hesitancy in parents.

On-Site Fluorination for Enhancing Utilization of Lithium in a Lithium-Sulfur Full Battery.

The rechargeability of the lithium anode in lithium-sulfur (Li-S) batteries is an issue for this type of battery. In this work, we demonstrate a Li-S full battery comprising a protected anode scaffold and a Li2S cathode. The stabilized performance is attained by an on-site fluorination strategy, using BiF3 for the interfacial coating of the anode. Unlike previously reported LiF protective coating derived from the vapor/solution depositions, BiF3 nanocrystals would be lithiated on-site to the anode surface and server as the protective layer. The chemically inertial Li3Bi alloy can provide additional ion-conductive paths and stitch the LiF to form a seamless protective layer, thereby suppressing the dendrite propagation and parasitic reactions effectively. With the designed anode structures and compositions, the high-loading full battery (8.05 mg cm-2) can achieve an exceptional utilization of both sulfur (898 mAh gS-1) and lithium (1533 mAh gLi-1) over 200 cycles, marking a step toward cyclable Li metal batteries at a high capacity.

Rational design of spontaneous reactions for protecting porous lithium electrodes in lithium-sulfur batteries.

A rechargeable lithium anode requires a porous structure for a high capacity, and a stable electrode/electrolyte interface against dendrite formation and polysulfide crossover when used in a lithium-sulfur battery. Here, we design two simple steps of spontaneous reactions for protecting porous lithium electrodes. First, a reaction between molten lithium and sulfur-impregnated carbon nanofiber forms a fibrous network with a lithium shell and a carbon core. Second, we coat the surface of this porous lithium electrode with a composite of lithium bismuth alloys and lithium fluoride through another spontaneous reaction between lithium and bismuth trifluoride, solvated with phosphorous pentasulfide, which also polymerizes with lithium sulfide residual in the electrode to form a solid electrolyte layer. This protected porous lithium electrode enables stable operation of a lithium-sulfur battery with a sulfur loading of 10.2 mg cm-2 at 6.0 mA cm-2 for 200 cycles.

Lattice Boltzmann simulation of dense gas flows in microchannels.

It is true that the Knudsen number that characterizes gas flows in microchannels increases to a finite value as the geometric dimension is reduced. However, since the gas in such a flow may retain a small mean free path and a small mean molecular spacing, the gas can still be rather dense in microdevices. Gas flows in microchannels have mainly been studied by molecular dynamics and direct simulation Monte Carlo methods. However, both methods are computationally expensive. In this work, we study dense gas flows in microchannels using an Enskog equation-based lattice Boltzmann Bhatnagar-Gross-Krook model. It is found that a dense gas flowing through a microchannel behaves different than a dilute gas under the same flow conditions.

Discrete effects on boundary conditions for the lattice Boltzmann equation in simulating microscale gas flows.

The lattice Boltzmann equation (LBE) has shown its promise in the simulation of microscale gas flows. One of the critical issues with this advanced method is to specify suitable slip boundary conditions to ensure simulation accuracy. In this paper we study two widely used kinetic boundary conditions in the LBE: the combination of the bounce-back and specular-reflection scheme and the discrete Maxwell's scheme. We show that (i) both schemes are virtually equivalent in principle, and (ii) there exist discrete effects in both schemes. A strategy is then proposed to adjust the parameters in the two kinetic boundary conditions such that an accurate slip boundary condition can be implemented. The numerical results demonstrate that the corrected boundary conditions are robust and reliable.

Thermal lattice Boltzmann equation for low Mach number flows: decoupling model.

A lattice Boltzmann model is proposed for solving low Mach number thermal flows with viscous dissipation and compression work in the double-distribution-function framework. A distribution function representing the total energy is defined based on a single velocity distribution function, and its evolution equation is derived from the continuous Boltzmann equation. A lattice Boltzmann equation model with clear physics and a simple structure is then obtained from a kinetic model for the decoupled hydrodynamic and energy equations. The model is tested by simulating a thermal Poiseuille flow and natural convection in a square cavity, and it is found that the numerical results agree well with the analytical solutions and/or the data reported in previous studies.

Multiwalled carbon nanotube supported PtRu for the anode of direct methanol fuel cells.

The activity of the methanol oxidation reaction of a multiwalled carbon nanotube (MWCNT)-supported PtRu catalyst was investigated and compared with the Vulcan XC-72 carbon-supported catalyst. The PtRu nanoparticles with 1:1 and 7:3 atomic ratios (with similar PtRu loadings and morphological structures) were deposited both on the MWCNTs and on the carbon. Cyclicvoltammetry results demonstrated that the MWCNT-supported PtRu catalyst exhibited a higher mass activity (mA mg(-1) of PtRu) for the methanol oxidation reaction than the carbon-supported PtRu under the condition that both catalysts possess more or less the same PtRu loadings, particle sizes, dispersions, and electrochemical surface area. The direct methanol fuel cell performance test data showed that MWCNT-supported PtRu catalysts yielded about 35-39% higher power densities than the carbon-supported PtRu.

Lattice Boltzmann method for incompressible flows with large pressure gradients.

Conventional lattice Boltzmann Bhatnagar-Gross-Krook (LBGK) models can simulate incompressible flows correctly only if the Mach number M and the density variation deltarho are negligibly small. However, the equation of state p=RTrho resulting from the conventional models limits their application to incompressible flows with a rather small pressure gradient. In this paper, based on the Enskog equation, we propose a finite difference lattice BGK model for isothermal incompressible flows with the resulting equation of state and transport properties suitable for nonideal fluids. We validated this model by simulating the plane Poiseuille flow, the two dimensional Womersley flow, and the backward-facing step flow and found that the numerical results obtained by the proposed model are more accurate than those by the conventional LBGK models when the pressure gradient imposed on the flows increases.

Finite-difference-based lattice Boltzmann model for dense binary mixtures.

We propose a finite-difference-based lattice Boltzmann model for dense binary mixtures based on the Enskog theory. The model is applicable to a mixture composed of two dense fluids with different shear viscosities. The macroscopic hydrodynamic and diffusion equations are derived from the model through the Chapmann-Enskog procedure. The model is also validated numerically.

Temperature dependence of the velocity boundary condition for nanoscale fluid flows.

Velocity slips may occur as a fluid flows over a solid surface in the nanometer scale. The slip length L(s) , characterizing the degree of slip, is usually used to describe the velocity boundary condition at the fluid/solid interface. In this work, we show that for a given wall-fluid system, the slip length L(s) generally varies with the system temperature T . In particular, we show that it is possible to create a pair of solid wall and fluid systems, in which the velocity slip becomes rather small and independent of temperature.

Simple kinetic model for fluid flows in the nanometer scale.

Fluid flows in the nanometer scale can be studied by molecular dynamics or Monte Carlo methods, but the time and length scales are usually limited to rather short ranges due to the computational expense. Kinetic theory is an alternative tool for studying nanoscale flows, but the existing models are rather complicated and difficult to implement. In this paper, we propose a simple Enskog-like kinetic model for nanoscale flows. The results predicted by this model compare well with molecular dynamics or Monte Carlo simulation results in the literature.