On the basis of previous work, we propose a phenomenological computable Boltzmann model equation synchronously involving polyatomic molecular internal energies, dissociation and recombination effects for multicomponent gases in this paper. Here, the distribution functions of each species have nine independent variables, which are time, physical space, molecular velocity, rotational energy and vibrational energy, if this component is a polyatomic gas. In this model equation, the concept of 'chemical reaction rate' is introduced in the chemical collision term to characterize the affect of chemical reactions. In order to make this complex model equation being 'computable', reduced distribution functions are adopted to get rid of two independent variables about rotational energy and vibrational energy of polyatomic component. We prove the conservation of this model equation, and then numerically solve it by the framework of gas-kinetic unified algorithm (GKUA), which is one kind of discrete velocity method (DVM). Here, non-catalytic boundary condition is adopted. Finally, a simple hypersonic flow around a cylinder with Mach number being 24.85 is numerically simulated to verify this model equation. In this case, four different components and eight chemical reactions are considered. It is shown that, this proposed Boltzmann model equation has the potential to be used to simulate thermochemical non-equilibrium effects of hypersonic flows covering various regimes.

The scattering light intensity can be enhanced in the Rayleigh scattering measurement velocity test by adding a small quantity of nanoparticles into the low-density wind tunnel flow field. Whether nanoparticles can adapt to variations in the flow velocity is a key factor for the accuracy of the measurement result. To investigate whether the measurement velocity of nanoparticles by the Rayleigh scattering test can represent the local flow field velocity, a two-way coupling DSMC method used in rarefied two-phase flow is applied to simulate the following features of nanoparticles in low-density flow fields with large grads. TiO2 particles with diameters of 10 nm, 50 nm, and 100 nm in low-density hypersonic flows around a spaceship model in cases M6 and M12 are carried out. The following features of a variety of nanoparticle sizes in different rarefication flows are distinguished, and the following feature of smaller nanoparticle sizes is good in complex hypersonic flows. In the simulation results, the 10 nm nanoparticle following feature in the lower rarefication of M6 is better and in good agreement with the Rayleigh scattering measurement result. The following features of particles with diameters larger than 50 nm are bad, and in the higher rarefication of M12, even the 10 nm nanoparticle’s following features become worse. This means that the velocity of particles measured by Rayleigh scattering cannot reflect the velocity of the flow field.

Fructus mori polysaccharide (FMP) has a variety of biological activities. In this study, the results showed that FMP alleviated hyperglycemia, insulin resistance, hyperlipidemia, endotoxemia, and high metabolic inflammation levels in type 2 diabetic (T2DM) mice. Next, it was found that the above beneficial effects of FMP on diabetic mice were significantly attenuated after antibiotics eliminated intestinal microbiota (IM) of mice. In addition, FMP suppressed intestinal inflammation and oxidative stress levels by inhibiting the activation of the TLR4/MyD88/NF-κB pathway, and indirectly upregulated the expression of the tight junction proteins Claudin-1, Occludin, and Zonula occlusionn-1 (ZO-1) to repair the intestinal barrier. Interestingly, the protective effect of FMP on the intestinal barrier was also attributed to its regulation of IM. The 16S rRNA and Spearman correlation analysis showed that FMP could repair the intestinal barrier to improve T2DM by remodeling specific IM, especially by significantly inhibiting 93.66 % of endotoxin-producing Shigella and promoting the proliferation of probiotic Allobaculum and Bifidobacterium by 16.31 % and 19.07 %, respectively. This study provided a theoretical support for the application of FMP as a novel probiotic in functional foods for diabetes.

Abstract Based on the Direct Simulation Monte Carlo (DSMC) method, an unsteady flow, which is caused by the interaction of two counter-flow jets with a hypersonic free stream, is constructed and simulated in the rarefied regime for the flight altitude of 90 km. In this complex three-dimensional rarefied flow, although the hypersonic free stream and all counter-flow jets are stable, their interaction area has great instability. This signifies that this extensive interaction area will not reach a final stable state in the DSMC simulation process. This study exhibits the unsteady evolution of the interaction area.

Counter-flow engines are often used for aircraft slowing or separating. In order to study the interaction between the counter-flow jets and free stream at high altitudes, the rarefied flow driven by two counter-flow jets and hypersonic free stream was constructed. By the direct simulation Monte Carlo (DSMC) method, it is found that a large area of mutual interference will be formed under the condition of rarefied free stream, and there are serious unsteady flow phenomena in the interference area. According to preliminary analysis, the range and unsteady evolution of the interference area are closely related to the kinetic energy of free stream and the flow rate of counter-flow jets.

The gas-kinetic unified algorithm solving the Boltzmann modeling velocity distribution function equation is developed and employed to study gas dynamic problems covering various flow regimes. Based on the computable modeling of Boltzmann equation, the modeled velocity distribution function equation covering to various flow regimes is presented. The discrete velocity ordinate method is developed and applied to remove the velocity space dependency of the distribution function. Based on the uncoupling technique on molecular movement and collision in the DSMC method, the gas-kinetic finite difference scheme is constructed to directly solve the discrete velocity distribution functions by using the unsteady time-splitting method from computational fluid dynamics. The discrete velocity numerical integration method with the Gauss-type weight function is developed to evaluate the macroscopic flow variables at each point in the physical space. The parallel implementation for the gas-kinetic numerical method is investigated to solve the three-dimensional complex flows. To validate the accuracy and feasibility of the present numerical method, onedimensional shock wave problems, supersonic flows past two-dimensional circular cylinder and three-dimensional hypersonic flows past sphere and spacecraft shape covering various flow regimes are simulated with different Knudsen numbers and Mach numbers. The computational results are found in good agreement with the related theoretical, DSMC, N-S, and experimental data. The computing practice has confirmed that the present gas-kinetic algorithm probably provides a promising approach to resolve the hypersonic aerothermodynamics problems with the complete spectrum of flow regimes from the gas-kinetic point of view of solving the unified Boltzmann model equation. & COPY;2023 L & H Scientific Publishing, LLC. All rights reserved.

Currently, multidrug resistant (MDR) bacterial infections are a great threat to public health, and the development of novel strategies for high efficiency combatting of MDR bacteria is in urgent demand. Hydrogen (H2) is a small gas with a high reducing ability, and plenty of recent studies have demonstrated its therapeutic effect on many diseases. However, the antibacterial effectiveness and mechanism of H2 against MDR bacteria are still unknown. In the present work, using PdH nanohydride with a temperature responsive H2-releasing property as the H2 source, we demonstrated that H2 was not only able to inhibit the growth of normal Staphylococcus aureus (S. aureus), but could also effectively eliminate single drug resistant S. aureus (CRSA) and multidrug resistant S. aureus (MRSA), as well as the biofilms formed by those bacteria. Moreover, an in-depth mechanism regarding the anti-antibiotic-resistance activity of H2 was elucidated by us, in which H2 exerted its antibacterial effect by firstly causing severe membrane damage, followed by boosting generation of intracellular ROS, which subsequently triggered DNA damage and finally led to bacterial death. The proposed mechanism was further verified by genomic analysis, where a cluster of genes related to bacterial membrane integrity, biofilm formation, metabolism and DNA functions was significantly perturbed by the released H2. In particular, H2 boosted intracellular ROS generation by destroying the redox homeostasis of bacterial metabolism. More importantly, we revealed that H2 was able to alleviate the antibiotic resistance of CRSA and MRSA by significantly down-regulating the expression of many drug-resistant genes, e.g. the norG gene of CRSA, and fmtA, gpsB, sarA and marR genes of MRSA, as well as reducing the minimal inhibitory concentration (MIC) of ciprofloxacin/ampicillin against CRSA/MRSA. The findings in our work suggested that H2 therapy is a promising tool for combating antibiotic-resistant bacteria.

Low-carbohydrate diet is currently a more focused diet for diabetes,which includes low-carbohydrate,high-fat diet and low-carbohydrate,high-protein diet. Low-carbohydrate diets control weight and blood sugar by reducing glucose availability through gluconeogenesis and ketogenesis. But this diet has a lot of negative effects on the body. This paper reviews the effects of low carbohydrate diet on blood vessels,myocardium and kidney in patients with type 2 diabetes mellitus,and the research progress of dietary compliance of this diet,so as to provide reference for the influence of low carbohydrate diet on patients with type 2 diabetes.

In this paper, a kinetic Boltzmann model equation involving internal degrees of freedom is constructed for thermodynamic non-equilibrium polyatomic gases, in which the continuous distribution mode of rotational energy and discrete quantum effect of the vibrational energy are both considered, respectively. By theoretically analyzing the "recurrence feature" of this model, it is found that the root of the quantum effect comes from the translational rotational-vibrational relaxation term (G(3)(t,r,v)), because of the additional term relative to the continuous distribution mode of vibrational energy. Besides, some important properties of this model are also analyzed and proved, including the conservative property and entropy inequality. Then, the balance equations on each vibrational energy level and balance equations about macroscopic variables are derived by the moment method. The corresponding thermodynamic relationship in the hydrodynamic limit is also analyzed by the simplified version of Chapman-Enskog method, and the correct Prandtl number is obtained. Numerical methods and wall surface boundary condition to solve this model equation are presented here. Finally, planar flows past a cylinder with different Mach numbers are numerically simulated to test and verify the reliability of this model, and to analyze the influence rules of the excited quantum vibrational energy for polyatomic gas flows. (c) 2020 Published by Elsevier Inc.

Summary The nonequilibrium steady gas flows under the external forces are essentially associated with some extremely complicated nonlinear dynamics, due to the acceleration or deceleration effects of the external forces on the gas molecules by the velocity distribution function. In this article, the gas‐kinetic unified algorithm (GKUA) for rarefied transition to continuum flows under external forces is developed by solving the unified Boltzmann model equation. The computable modeling of the Boltzmann equation with the external force terms is presented at the first time by introducing the gas molecular collision relaxing parameter and the local equilibrium distribution function integrated in the unified expression with the flow state controlling parameter, including the macroscopic flow variables, the gas viscosity transport coefficient, the thermodynamic effect, the molecular power law, and molecular models, covering a full spectrum of flow regimes. The conservative discrete velocity ordinate (DVO) method is utilized to transform the governing equation into the hyperbolic conservation forms at each of the DVO points. The corresponding numerical schemes are constructed, especially the forward‐backward MacCormack predictor‐corrector method for the convection term in the molecular velocity space, which is unlike the original type. Some typical numerical examples are conducted to test the present new algorithm. The results obtained by the relevant direct simulation Monte Carlo method, Euler/Navier‐Stokes solver, unified gas‐kinetic scheme, and moment methods are compared with the numerical analysis solutions of the present GKUA, which are in good agreement, demonstrating the high accuracy of the present algorithm. Besides, some anomalous features in these flows are observed and analyzed in detail. The numerical experience indicates that the present GKUA can provide potential applications for the simulations of the nonequilibrium external‐force driven flows, such as the gravity, the electric force, and the Lorentz force fields covering all flow regimes.

目的:以益生菌副干酪乳杆菌R8为研究对象,进行双层包埋关键工艺参数的研究,以提高菌体的稳定性,并实现在肠道定向释放的目的.方法:筛选冻干保护剂、益生元;优化微胶囊包埋材料海藻酸钠和固化液中氯化钙浓度;检测和分析制得的微胶囊在人工胃液和人工肠液中的释放特性.结果:筛选出的最佳冻干保护剂为20％全蛋液;最佳益生元为菊粉;最佳包埋液配方为:5％益生菌、2％菊粉、20％全蛋液,1％海藻酸钠;最佳固化液配方为2.5％氯化钙.所得微囊颗粒可耐受胃液破坏,在模拟肠环境中45 min内释放完毕,人工肠液中活菌数为原微囊活菌数的65.6％.全蛋液在制备工艺过程起到保护作用,并提高在储存过程中的稳定性;将菌体/蛋白质/海藻酸钠微胶囊进一步用壳聚糖材料进行覆膜,可实现在肠道定向释放.

药食同源植物是指既可以作为食品又可以作为药品的植物,被广泛用于日常养生保健.利用微生物的分解能力处理药食同源植物,可提高其药用价值.从微生物发酵药食同源植物的常用菌种、作用机理和特点、技术进展及其在食品和医药领域的应用4个方面展开综述,并对其发展趋势进行展望,以期为微生物发酵处理药食同源植物产品的开发提供依据.

通过对未酶解果胶香蕉带渣果酒发酵工艺及澄清方法进行了初步的探讨,试验结果表明,采用不同发酵菌种发酵香蕉酒品质差异较大,3号酵母发酵酒的色香味较好,利用带渣发酵工艺制备香蕉果酒是可行的;利用3种方法对带渣发酵的香蕉果酒进行澄清,其中第3种澄清方法的效果较佳,酒精的损失在10％以下,总糖损失率均低于20％,酒液透过率均达到90％以上,酒液清亮透明,且对澄清后的酒香味、风味无影响.解决了香蕉带渣发酵酒的澄清问题,带渣发酵工艺制备的香蕉酒香味浓郁,且省去了果胶酶解和去果渣工艺步骤,简化了生产工艺,降低了生产成本.

The kinetic models involving rotational and vibrational degrees of freedom are constructed to analyze the thermodynamic non-equilibrium effect of polyatomic gases, in which the continuously distributed modes of the internal energies and discrete quantum effect of the vibrational energy are both considered respectively. The root of the quantum effect comes from the translational-rotational-vibrational relaxation by study the normalization principle of the quantum model equation. Finally, planar flows past a cylinder are numerically simulated to test and verify the reliability of the models in a supersonic case, and to analyze the influences of the excited internal energies for polyatomic gas flows.

The optimization of fermentation medium for a strain of Lactobacillus R8,which had been proved to be resistant to acid and bile,lays a foundation for the probiotics to be used to improve the gastrointestinal tract healthy food.The components of fermentation medium were optimized by single factor test and orthogonal design test based on the density of bacteria.The results showed that the best fermentation formula for the bacterium was:glucose 20.0 g,yeast powder 30.0 g,MnSO4 ·4H2 O 0.075 g,MgSO4 ·7H2O 2.0 g,KH2PO4 2.5 g,citric acid ammonium 2.5 g,CH3COONa· 3H2O 6.25 g,Tween80 1.0 mL,pH6.2.After optimization,the concentration of bacteria(OD600 nm) reached 2.38.

以乳杆菌R8菌株为材料,对其高密度发酵培养工艺进行了研究.以菌体密度(OD600)及碳源(葡萄糖)的利用情况为主要参考指标,研究了中和剂、pH、接种量、初始糖含量、通气方式以及补料工艺等对菌体在发酵罐内生长的影响,并对试验菌进行250 L中试放大工艺的优化.优化菌体小试发酵工艺为:将种子液以8％(V/V)的接种量接种于装液量70％的小罐,初糖浓度40 g/L,搅拌转速100 r/min,间歇通氮气维持一定的厌氧环境,自动流加12.5％的氨水控制pH恒定在5.8,37℃恒温发酵.250 L中试发酵工艺为:将控制pH 5.8,37℃恒温发酵7h左右的种子液以8％接种量接种于装液量为70％的250 L发酵罐,搅拌转速60 r/min,自动流加氨水控制pH 5.8,间歇通氮气不保压(每2h以0.2 vvm的速率通氮气5 min),37℃恒温发酵10h左右结束.250 L规模所得发酵液的活菌浓度约为8× 109 CFU/mL,经真空冷冻干燥所得的菌粉活菌浓度约为1.2×1011 CFU/g.

益生菌具有调节肠道微生物平衡、增强免疫力等保健功能.通过阐述药食同源植物成分促进益生菌增殖,植物有效成分在益生菌分泌酶系转运下吸收,益生菌发酵药食同源植物可产生新的利于吸收成分、增强活性、降低副作用等三方面综述益生菌与药食同源植物的协同作用;足量的活菌数是益生菌产品发挥作用的必要条件,结合适当益生元(如药食同源植物成分)的合生元产品可保证菌株的存活,还可提高益生菌产品的功能性.展望开发以药食同源植物提取物为益生元的新一代合生元产品.

健固片是以氨基葡萄糖盐酸盐、硫酸软骨素、葛根提取物、柠檬酸苹果酸钙和维生素D3为原辅料制成的具有增加骨密度功能的保健食品.氨基葡萄糖是一种氨基单糖,主要存在于机体的关节软骨中,是关节软骨基质合成蛋白聚糖必需的重要物质.硫酸软骨素是一种蛋白多糖分子,是软骨的主要成分.氨基葡萄糖和硫酸软骨素对人类的骨质疏松症治疗具有协同效应[1].葛根提取物来自豆科植物野葛Pueraria lobata(Willd.) Ohwi的干燥根,有研究表明可减少大鼠的骨吸收,促进骨形成,增加骨密度[2].

Melatonin, as an endogenous hormone in humans, plays an important role in inducing natural sleep. The secretion of melatonin, which can be modulated by the rhythms of day and night, is associated with ages. In this paper, we summarized the physiological role and regulation mechanism of melatonin during sleep. Melatonin functions as regulators in improving sleep quality and endocrine modulation. The research progression of melatonin in modify-ing sleeping products was also introduced.

In order to understand the mechanism behind the high production of L-malate (LMA) by Aspergillus sp.Nl-14',its total DNA was extracted to be used as the template,homologous primers were designed to amplify the segment containing the full length of the pyruvate carboxylase gene (pyc) and the malate dehydrogenase gene (mdh),and sequencing was then performed.Based on the results of this sequencing,the coding regions ofpyc and mdh were identified,their coding sequences were amplified from the total cDNA of Nl-14'using the designed primers,and sequencing was carded out through TA cloning.The results of the sequencing showed that the open reading frame (ORF) of pyc had 3582 bp and it encoded 1193 amino acids.The analysis of the results showed that the amino acid sequence ofpyruvate carboxylase (PYC) was quite conserved in Aspergillus species as the sequence similarity with other Aspergillus species was higher than 90 ％.Mutations occurred at two conserved sites of N1-14',833(A) and 1022(F),which were located in a loop and in the middle of α-helix,respectively,suggesting that those mutations may be relevant to the high production of LMA.The ORF ofmdh had 1023 bp and it encoded 340 amino acids.The amino acid sequence of malate dehydrogenase (MDH) was also conserved across the Aspergillus species,and there were two amino acid mutation sites in the conserved domain.Both of them were situated in the α-helix.In this experiment,two genes related to the key process of producing LMA in N1-14'were cloned,the specificity of these two genes was analyzed,and the function of the specific amino acid sites were predicted.This study provides a basis for further study on the mechanisms behind the high production of LMA and genetic manipulations required for increasing its production.