A wealth distribution model with a non-Maxwellian collision kernel

A non-Maxwellian collision kernel is employed to study the evolution of wealth distribution in a multi-agent society.The collision kernel divides agents into two different groups under certain conditions. Applying the kinetic theory of rarefied gases, we construct a two-group kinetic model for the evolution of wealth distribution. Under the continuous trading limit, the Fokker–Planck equation is derived and its steady-state solution is obtained. For the non-Maxwellian collision kernel, we find a suitable redistribution operator to match the taxation. Our results illustrate that taxation and redistribution have the property to change the Pareto index.

非贵金属催化剂的合成及其电解水制氢——推荐一个综合化学实验

介绍一个电解水制氢催化剂的合成、物性表征及其性能评价的综合实验。本实验采用水热法和湿化学法制备了Cu-MoS_(2)/CNTs电催化剂,之后应用伏安法和交流阻抗技术评价了催化剂的性能,以巩固学生对于不可逆电极和超电势概念的理解和学习。本实验通过合成和筛选最佳组分的电催化剂,有助于激发学生的科研兴趣和提高学生综合实验能力。

小麦TaMYB1A负调控苯丙烷代谢途径及植株的株高

苯丙烷途径是植物次生代谢产物合成的重要途径之一,可合成木质素、类黄酮和芥子酰基苹果酸类等化合物。该途径所产生的化合物不仅影响植物的生长发育及胁迫反应,还能用于生产香料、农药、染料、医药、饲料和生物质能源等。植物中的R2R3-MYB蛋白在植物次生代谢调节、器官发育和应对环境胁迫反应等方面均发挥重要的生物学功能。小麦(Triticum aestivum L.)是重要的粮食作物,在生产粮食的同时会产生大量秸秆等生物质;因此,研究小麦R2R3-MYB类转录因子在植物苯丙烷途径中的功能及调控机制对有效利用小麦秸秆具有重要意义。RT-PCR分析表明,TaMYB1A在小麦孕穗期的茎中表达水平较高;GFP-TaMYB1A融合蛋白在烟草表皮细胞中主要定位于细胞核;TaMYB1A在酵母系统中具有转录抑制活性。本研究以过表达TaMYB1A的转基因拟南芥株系为材料,分析了TaMYB1A对木质素积累/合成以及类黄酮化合物合成的影响。结果表明,过表达TaMYB1A抑制转基因拟南芥株系的株高(P<0.05),并显著降低了转基因拟南芥株系中木质素(P<0.05)和类黄酮(P<0.05)的合成。酵母单杂交结果显示,TaMYB1A能结合于拟南芥At4CL1、AtC4H、AtC3H和AtCHS以及小麦Ta4CL1和TaC4H1的启动子区;双荧光素酶报告系统显示,TaMYB1A抑制拟南芥中上述4个基因的表达;遗传学分析表明,TaMYB1A抑制小麦Ta4CL1和TaC4H1的表达;基因芯片和qRT-PCR结果表明,过量表达TaMYB1A抑制了转基因拟南芥苯丙烷途径中多数基因的表达;且转基因株系中4CL酶活性显著下降(P<0.05)。综上所述,小麦TaMYB1A属于R2R3型第四亚组MYB转录因子,通过与拟南芥和小麦苯丙烷途径关键基因的启动子结合并抑制相关基因的表达,从而负调控苯丙烷代谢途径及转基因株系的株高。

Constraining the Orbital Inclination and Companion Properties of Three Black Widow Pulsars Detected by FAST

Black widows(BWs)are millisecond pulsars ablating their companion stars.The out-flowing material from the companion can block the radio emission of the pulsar,resulting in eclipses.In this paper,we construct a model for the radio eclipse by calculating the geometry of the bow shock between the winds of the pulsar and companion,where the shock shapes the eclipsing medium but had not been described in detail in previous works.The model is further used to explain the variations of the flux density and dispersion measure of three BW pulsars(i.e.,PSR B1957+20,J2055+3829,and J2051-0827)detected by the Five-hundred-meter Aperture Spherical radio Telescope.Consequently,we constrained the parameters of the three BW systems such as the inclination angles and true anomalies of the observer as well as the mass-loss rates and wind velocity of the companion stars.With the help of these constraints,it is expected that magnetic fields of companion stars and even masses of pulsars could further be determined as some extra observation can be achieved in the future.

决明子总蒽醌对脂多糖诱导大鼠急性肝损伤的作用及其机制探讨

目的观察决明子总蒽醌对脂多糖(LPS)诱导的急性肝损伤(ALI)大鼠的作用及对HMGB1/TLR4/NF-κB信号通路的影响。方法将60只大鼠随机分为对照组、模型组、低剂量组、中剂量组和高剂量组,除对照组外其余大鼠给予尾部静脉注射LPS(5 mg/kg)复制ALI模型,对照组给予等体积的生理盐水。低、中、高剂量组在模型复制后每日分别给予大鼠灌胃1次10 mg/kg、20 mg/kg及40 mg/kg的决明子总蒽醌,灌胃剂量5 ml,连续给药14 d;对照组和模型组给予同等体积生理盐水。检测大鼠丙氨酸氨基转移酶(ALT)、总胆红素(TBIL)及天门冬氨酸基转移酶(AST),HE染色观察肝组织病理变化,TUNEL染色检测各组大鼠肝组织中的细胞凋亡,ELISA法检测肝组织中的肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)及白细胞介素-1β(IL-1β),Western blotting检测高迁移率族蛋白B1(HMGB1)、Toll样受体4(TLR4)及核因子κB(NF-κB)蛋白表达量。结果模型组ALT、AST及TBIL水平较对照组升高(P<0.05),中、高剂量组较模型组下降(P<0.05)。模型组肝细胞凋亡率较对照组升高(P<0.05),中、高剂量组较模型组下降(P<0.05)。模型组肝组织中IL-6、IL-1β和TNF-α水平较对照组升高(P<0.05),中剂量组、高剂量组较模型组下降(P<0.05)。模型组HMGB1、TLR4及NF-κB蛋白相对表达量较对照组升高(P<0.05),中、高剂量组较模型组下降(P<0.05)。结论决明子总蒽醌可以抑制LPS诱导ALI大鼠的HMGB1/TLR4/NF-κB信号通路的激活,从而减轻炎症反应,发挥对肝脏的保护作用。

基于水热技术的粪便污水中病原微生物灭活试验研究

针对新冠肺炎疫情持续阶段氯消毒工艺的劣势及应急状态的需求,开展水热强化灭菌技术处理粪便污水的研究。以大肠菌群和细菌作为指示微生物,探索不同温度下水热对样品中微生物的杀灭特性。结果表明,120~180℃温度下均可实现水样中微生物的完全灭活,且24 h放置后样品中微生物无法复活和增殖,可作为一种含病毒污水消毒工艺在应急状态下使用。连续式水热强化灭菌设备适合作为应急水处理设施对医疗废水、污泥和粪便进行消毒灭菌。

Overwhelming low ammonia escape and low temperature denitration efficiency via MnOx-decorated two-dimensional MgAl layered double oxides

Low temperature catalysts are attracting increasing attention in the selective catalytic reduction(SCR)of NO with NH3.Mn Ox-decorated Mg Al layered double oxide(Mn/Mg Al-LDO)was synthesized via a facile fast pour assisted co-precipitation(FP-CP)process.Compared to the Mn/Mg Al-LDO obtained via slow drop assisted coprecipitation(SD-CP)method,the Mn/Mg Al-LDO(FP-CP)has excellent activity.The Mn/Mg Al-LDO(FP-CP)catalyst was shown to possess a high NO conversion rate of 76%-100%from 25 to 150℃,which is much better than the control Mn/Mg Al-LDO(SD-CP)(29.4%-75.8%).In addition,the Mn/Mg Al-LDO(FP-CP)offered an enhanced NO conversion rate of 97%and a N2selectivity of 97.3%at 100℃;the NO conversion rate was 100%and the N2selectivity was 90%at 150℃with a GHSV of 60,000 h^-1.The Mn/Mg Al-LDO(FP-CP)catalyst exhibited a smaller fragment nano-sheet structure(sheet thickness of 7.23 nm).An apparent lattice disorder was observed in the HRTEM image confirming the presence of many defects.The H2-TPR curves show that the Mn/Mg Al-LDO(FP-CP)catalyst has abundant reducing substances.Furthermore,the enhanced surface acidity makes the NH3concentration of the Mn/Mg Al-LDO(FP-CP)catalyst lower than 100 ml·m^-3after the reaction from 25 to 400℃.This can effectively reduce the ammonia escape rate in the SCR reaction.Thus,the Mn/Mg Al-LDO(FP-CP)catalyst has potential applications in stationary industrial installations for environmentally friendly ultra-low temperature SCR.

Magnesium composites with hybrid nano-reinforcements:3D simulation of dynamic tensile response at elevated temperatures

3D numerical simulations of dynamical tensile response of hybrid carbon nanotube(CNT)and SiC nanoparticle reinforced AZ91D magnesium(Mg)based composites considering interface cohesion over a temperature range from 25 to 300℃ were carried out using a 3D representative volume element(RVE)approach.The simulation predictions were compared with the experimental results.It is clearly shown that the overall dynamic tensile properties of the nanocomposites at different temperatures are improved when the total volume fraction and volume fraction ratio of hybrid CNTs to SiC nanoparticles increase.The overall maximum hybrid effect is achieved when the hybrid volume fraction ratio of CNTs to SiC nanoparticles is in the range from 7:3 to 8:2 under the condition of total volume fraction of 1.0%.The composites present positive strain rate hardening and temperature softening effects under dynamic loading at high temperatures.The simulation results are in good agreement with the experimental data.

The effects of large doses of vitamin C and vitamin E on nerve injury, neurotrophic and oxidative stress in patients with acute craniocerebral injury

Objective:To study the effects of large doses of vitamin C and vitamin E on nerve injury,neurotrophic and oxidative stress in patients with acute craniocercbral injury.Methods:Patients with acute cranioccrebral trauma who were admitted to the Third People's Hospital of Zigong from April 2014 to December 2016 were selected as the subjects and were randomly divided into two groups.The control group received conventional treatment,and the intervention group received large doses of vitamin C and vitamin E combined with conventional treatment.On the yh day and 7th day after treatment,peripheral blood was collected and serum was isolated,then the contents of nerve injury index NSE,S 100B,NGB,UCH-L1,Tf,Ft and neurotrophic indexes NTF-α,BDNE NGF and IGF-I were determined by Enzyme-linked immunosorbent assay kit,and the contents of SOD,GPx,CAT,OH-,O2,MDA and AOPP were measured by radioactive immunoprecipitation kit.Results:3th day and 7th day after treatment,the contents of NSE,S100B,NGB,UCH-L1,Tf,Ft,NTF-α,BDNF,NGF,IGF-Ⅰ,OH-,O2-,MDA and AOPP in the intervention group were all significantly lower than those in the control group.The content of SOD,GPx and CAT in serum in the intervention group was significantly higher than that in the control group.Conclusions:High-dose vitamin C and vitamin E treatment can alleviate nerve injury,oxidative stress response,and improve neurotrophic state in patients with acute craniocerebral injury.

Risk factors for relapse and nomogram for relapse probability prediction in patients with minor ischemic stroke

BACKGROUND The identification of risk factors for recurrence in patients with minor ischemic stroke(MIS)is a critical medical need.AIM To develop a nomogram for individualized prediction of in-hospital recurrence in MIS patients.METHODS Based on retrospective collection,a single-center study was conducted at the First Affiliated Hospital of Anhui Medical University from January 2014 to December 2019.Univariate and multivariate logistic regression analyses were used to determine the risk factors associated with MIS recurrence.The least absolute shrinkage and selection operator regression was performed for preliminary identification of potential risk factors.Uric acid,systolic blood pressure,serum total bilirubin(STBL),and ferritin were integrated for nomogram construction.The predictive accuracy and calibration of the nomogram model were assessed by the area under the receiver operating characteristic curve(AUC-ROC)and Hosmer-Lemeshow test,respectively.RESULTS A total of 2216 MIS patients were screened.Among them,155 were excluded for intravascular therapy,146 for unknown National Institutes of Health Stroke Scale score,195 for intracranial hemorrhage,and 247 for progressive stroke.Finally,1244 patients were subjected to further analysis and divided into a training set(n=796)and a validation set(n=448).Multivariate logistic regression analysis revealed that uric acid[odds ratio(OR):0.997,95%confidence interval(CI):0.993-0.999],ferritin(OR:1.004,95%CI:1.002-1.006),and STBL(OR:0.973,95%CI:0.956-0.990)were independently associated with in-hospital recurrence in MIS patients.Our model showed good discrimination;the AUC-ROC value was 0.725(95%CI:0.646-0.804)in the training set and 0.717(95%CI:0.580-0.785)in the validation set.Moreover,the calibration between nomogram prediction and the actual observation showed good consistency.Hosmer-Lemeshow test results confirmed that the nomogram was well-calibrated(P=0.850).CONCLUSION Our present findings suggest that the nomogram may provide individualized prediction of recurrence in MIS patients.

有缆遥控潜水器(ROV)在智能水电厂中的应用

水电工程投资大、社会影响面广,定期对大坝进行安全检查,确保大坝安全显得尤为重要。以往大坝水下部分的安全检查主要依赖人工潜水作业的方式,面临效率低、风险大、成本高等突出问题。近年来,机器人技术快速发展,使得在智能水电厂中用机器人取代人工进行水下安全检查成为可能。在该背景下,分析了国内外有缆遥控潜水器(ROV)的发展现状,研究了当前主流ROV在水电工程中的应用情况及遇到的问题,在此基础提出了适用于水电工程的ROV需要解决的关键技术问题,为研制水电工程ROV装备提供科学依据。

Retinal stem cells transplantation combined with copolymer-1 immunization reduces interferon-gamma levels in an experimental model of glaucoma

AIM: To explore the effect of immunization with copolymer-1 (COP-1) and retinal stem cells (RSCs) transplantation on interferon-gamma (IFN-gamma) levels in a rat experimental glaucoma model. METHODS: An experimental glaucoma was induced by argon laser photocoagulation of the episcleral veins and limbal plexus in the right eye of rats. Immediately following glaucoma induction, rats were immunized with COP-1. RSCs were cultured and transplanted intravitreally into the eyes of glaucoma model animals 1 week post-laser treatment. Six experimental groups were used: COP-1/RSC, PBS/RSC, COP-1/PBS, PBS/PBS, glaucoma model group, and a normal control group. The concentration of IFN-gamma in aqueous humor (AH) and serum was measured by enzyme-linked immunosorbent assay (ELISA) in each of the six groups. Retinal ganglion cell (RGC) survival was assessed by quantifying apoptosis using Hoechst staining. RESULTS: Concentrations of IFN-gamma in AH and serum of rats that had undergone glaucoma induction were higher than those of non-induced control rats. The concentrations of IFN-gamma in AH and serum of the COP-1/RSCs treated group were determined to be 2371.9ng/L and 710.9ng/L, respectively, which were significantly lower than those in the other treated groups (P<0.05). In fact, IFN-gamma levels in the dual treated group were reduced to background levels. The COP-1/RSC group had lower number of apoptotic RGCs than the other three experimental groups (P<0.05). CONCLUSION: The reduced levels of IFN-gamma in AH and serum of the COP-1/RSC group may be related to synergistic effects between RSCs transplantation and COP-1 immune modulation. It is likely that the lower levels of IFN-gamma prevented RGCs glaucomatous apoptasis.

Prevalence and patterns of drug-resistance mutations among HIV-1 patients infected with CRF07_BC strains in Sichuan province,China

Little information is available on the prevalence of drug-resistance mutations in patients harboring the human immunodeficiency virus type 1(HIV-1) circulating recombinant form(CRF)07_BC variant in Sichuan, China. This study examined 375 plasma samples from patients with HIV-1 who were infected with the CRF07_BC strain, including 104 drug-naive participants and 271 in whom antiretroviral therapy(ART) had failed. Only one participant in the drug-naive group had a drug-resistance mutation(M46L), compared with 31.73% of those in whom ART had failed. Further analysis showed that 19.56% of strains contained mutations conferring resistance to non-nucleoside reverse transcriptase inhibitors(NNRTIs) alone, 0.74% were resistant to nucleoside reverse transcriptase inhibitors(NRTIs) alone, and 11.44% were dual-resistant to both NRTIs and NNRTIs. The most common mutation in the ART-failure group was M184V(35.88%), K103N(45.01%), Y181C(17.33%), and G190S/A(15.88%). The percentages of HIV-1 strains resistant to lamivudine, emtricitabine, efavirenz, etravirine, and nevirapine were 10.70%, 10.70%, 28.04%, 7.75%, and 26.20%, respectively. To explore site variants possibly related to drug resistance, variations in the ancestor/consensus CRF07_BC sequences from the therapy-naive and ART-failure groups were compared, and seven mutations at six positions were identified as being significantly differently distributed between the two groups(p<0.05). Detailed sequence data will provide information on CRF07_BC genetic characterizations, and improve our understanding of antiretroviral susceptibility and the evolution of drug-resistance mutations. This will be valuable in developing and implementing local public-health approaches for HIV drug-resistance prevention and treatment.

Effect of hybrid ratio on friction and wear behavior of AZ91D matrix nanocomposites under oil lubricated conditions

Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribometer.Friction coefficients and wear rates were measured within a load range of 200-1000 N at a spindle rotary speed of 380 r/min.Worn surface morphologies,phase and element compositions were studied by scanning electron microscope(SEM),X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS),respectively.The mechanism of synergistic effect of CNTs and SiC nanoparticles was discussed.The results indicate that the AZ91D nanocomposites show better wear resistance properties and different wear mechanisms compared with AZ91D.The AZ91D nanocomposites reinforced with 0.5%CNTs and 0.5%nano-SiC have the best tribological capacity.The wear mechanisms for the Mg-based hybrid nanocomposites appear to be a mix-up of micro-ploughing,micro-cutting,slight adhesive wear and delamination.

烯碳材料用于锌离子混合电容器的研究进展

随着可穿戴电子设备的出现,诸如锌离子混合电容器等绿色储能器件,因其具有安全性高、稳定性好、成本低、功率密度高、能量密度大的特点,从而受到了广泛的关注。对于锌离子混合电容器,烯碳材料(主要包括石墨烯和碳纳米管)由于其卓越的导电性和良好的机械稳定性,被认为是一种十分有前景的材料。在此,作者对用于锌离子混合电容器的烯碳基材料的改性策略进行了全面的综述,并对锌离子混合电容器的储能机理、锌阳极和电解液进行了简要总结。最后,还对锌离子混合电容器的未来研究方向进行了展望。

Effects of standardized three-stage rehabilitation combined with edaravone therapy on the neurotrophic state and oxidative stress injury in patients with cerebral infarction

Objective: To investigate the effects of standardized three-stage rehabilitation combined with edaravone therapy on the neurotrophic state and oxidative stress injury in patients with cerebral infarction. Methods: A total of 90 patients with acute cerebral infarction who were treated in the hospital between May 2015 and April 2017 were divided into control group (n=45) and observation group (n=45) by random number table. Control group received edaravone therapy, and observation group received standardized three-stage rehabilitation combined with edaravone therapy. The differences in neurotrophic state and oxidative stress injury were compared between the two groups before and after treatment. Results: There was no statistically significant difference in serum levels of neurotrophic indexes and oxidative stress indexes between the two groups before treatment. After treatment, serum neurotrophic indexes BDNF and NGF levels of observation group were higher than those of control group;serum oxidation indexes AOPPs, LHP and MDA levels were lower than those of control group whereas SOD, CAT and T-AOC levels were higher than those of control group. Conclusion:Standardized three-stage rehabilitation combined with edaravone therapy can effectively optimize the neurotrophic state and inhibit the oxidative stress in patients with cerebral infarction.

Hygroscopicity-resistant mechanism of an α-starch based composite binder for dry sand molds and cores

Hygroscopicity-resistance of an α-starch based composite binder for dry sand molds (cores) has been studiedexperimentally and theoretically. Focus is placed on the relationship between the hardening structure andhumidity-resistance of the composite binder. The results show that the α-starch composite binder has goodhumidity-resistance due to its special complex structure. SEM observations illustrate that the composite binder consists ofreticular matrix and a ball- or lump-shaped reinforcement phase, and the specific property of the binding membrane withheterogeneous structure is affected by humidity to a small extent. Based on the analyses on the interplays of differentingredients in the binder at hardening, the structure model and hygroscopicity-resistant mechanisms of the hardeningcomposite binder were further proposed. Moreover, the reasons for good humidity-resistance of the composite binderbonded sand are well explained by the humidity-resistant mechanisms.

The Multiple Images of the Plasma Lensing FRB

We investigate the formation of multiple images as the radio signals from fast radio bursts(FRBs)pass through the plane of a plasma clump.The exponential model for the plasma clump is adopted to analyze the properties of the multiple images.By comparing with the classical dispersion relations,we find that one image has exhibited specific inverse properties to others,such as their delay times at high frequency is higher than that at low frequency,owing to the lensing effects of the plasma clump.We demonstrate that these inverse effects should be observable in some repeating FRBs.Our results predict deviation in the estimated dispersion measure(DM)across multiple images,consistent with the observations of FRB 121102 and FRB 180916.J0158+65.If other plasma lenses have effects similar to an exponential lens,we find that they should also give rise to a similar dispersion relation in the multiple images.For some repeating FRBs,analysis of the differences in time delay and in DM between multiple images at different frequencies can serve as a method to reveal the plasma distribution.

The r-mode instability windows of strange stars

With the constraint from gravitational wave emission of a binary merger system(GW170817)and two-solar-mass pulsar observations, we investigate the r-mode instability windows of strange stars with unpaired and color-flavor-locked phase strange quark matter. Shear viscosities due to surface rubbing and electron-electron scattering are taken into account in this work. The results show that the effects of the equation of state of unpaired strange quark matter are only dominant at low temperature, but do not have significant effects on strange stars in the color-flavor-locked phase. A color-flavor-locked phase strange star,which is surrounded by an insulating nuclear crust, seems to be consistent with observational data of young pulsars. We find that an additional enhanced dissipation mechanisms might exist in SAX J1808.4–3658.Fast spinning young pulsar PSR J0537–6910 is a primary source for detecting gravitational waves from a rotating strange star, and young pulsars might be strange stars with color-flavor-locked phase strange quark matter.

Spin-down and emission variations for PSR J0742-2822

PSR J0742-2822 is known for its quasi-periodic changes in the observed pulse profile and spindown rate.In this paper,we analyzed 13 years of timing data obtained with the Nanshan 25-m radio telescope and the Parkes 64-m radio telescope.We found that the average values of the spin-down rate((v))of this pulsar changed in four different states.We investigated the correlation between v and W50,and ascertained that the correlation changed in different states.Moreover,not all the changes in states and correlation can be associated with glitch activities.We examined the long term evolution ofγ-ray flux(0.1-300 GeV)and the pulse profiles corresponding to the four different states using Fermi-LAT Pass8(P8 R3)data from 2008 August 5 to 2019 October 1.We did not detect a significant change inγ-ray flux or the pulse profile.Our results suggest that the connection between pulsar rotation and emission is more complex than previously reported for this pulsar.