Biodegradation of Phenol and 4-Chlorophenol by the Mutant Strain CTM 2

The biodegradations of phenol and 4-chlorophenol （4-cp） were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candida tropicalis. The results showed that the capacity of the CTM 2 to biodegrade 4-cp was increased up to 400 mg·L^-1 within 59.5 h. In the dual-substrate biodegradation both velocity and capacity of the CTM 2 to degrade 4-cp increased with low-concentration phenol. A totalof 400 mg·L^-1 4-cp was completely degraded within 50.＇5 h in thepresence of 300 mg·L^-1 phenol. The maximum 4：cp biodegegradation could reach 440 mg·L^1 with 120 mg·L^1 phenol. Low-concentration 4-cp caused great inhibition on the CTM 2 to degrade phenol. In addition, the kinetic behaviors were described using the kinetic model proposed in this lab.

A Comparison of the Biological Characteristics of EV71 C4 Subtypes from Different Epidemic Strains

The comparative analysis of the biological characterization and the genetic background study of EV71 circulating strains is commonly recognized as basic work necessary for development of an effective EV71 vaccine. In this study, we sequenced five EV71 circulating strains, isolated from Fuyang, Hefei, Kunming and Shenzhen city of China and named them FY-23, FY-22, H44, K9 and S1 respectively. The sequence alignment demonstrated their genotypes be C4. The genetic distance of the VP1 gene from these isolates suggested that they were highly co-related with genetic identity similar to other previously reported EV71 strains in China. Additionally, these strains were identified to display some obvious proliferation dynamics and plaque morphology when propagated in Vero cells. However, a distinctive difference in pathogenic ability in neonatal mice was found. Some differences in cross neutralization test & immunogenic analysis were also found. All these results are related to the biological characterization of circulating EV71 strains in China and aid in the development of an EV71 vaccine in the future.

Variation effect of strain rate on microstructure in isothermal compression of Ti-6Al-4V alloy

Isothermal compression of the Ti-6Al-4V alloy at the deformation temperatures of 950 and 980℃,height reductions of 30% and 60%,and strain rates of 0.001,0.010,0.100 and 1.000 s-1 was conducted,wherein the variations of microstructure with strain rate were investigated.The experimental results showed that the variation of the microstructure with the strain rate under one condition was significantly different from that under another condition,which meaned that the interaction between the processing parameters was great.The optimization of the strain rate under one condition was not suitable for another condition.Therefore,selecting the forging equipment and optimizing the strain rate should be based on simultaneously considering the deformation temperature and height reduction.

Mechanical characterization of Mg-B4C nanocomposite fabricated at different strain rates

Magnesium has wide application in industry.The main purpose of this investigation was to improve the properties of magnesium by reinforcing it using B4C nanoparticles.The reinforced nanocomposites were fabricated using a powder compaction technique for 0,1.5vol%,3vol%,5vol%,and 10vol% of B4C.Powder compaction was conducted using a split Hopkinson bar(SHB),drop hammer(DH),and Instron to reach different compaction loading rates.The compressive stress–strain curves of the samples were captured from quasi-static and dynamic tests carried out using an Instron and split Hopkinson pressure bar,respectively.Results revealed that,to achieve the highest improvement in ultimate strength,the contents of B4C were 1.5vol%,3vol%,and 3vol% for Instron,DH,and SHB,respectively.These results also indicated that the effect of compaction type on the quasi-static strength of the samples was not as significant,although its effect on the dynamic strength of the samples was remarkable.The improvement in ultimate strength obtained from the quasi-static stress–strain curves of the samples(compared to pure Mg)varied from 9.9% for DH to 24% for SHB.The dynamic strength of the samples was improved(with respect to pure Mg)by 73%,116%,and 141%for the specimens compacted by Instron,DH,and SHB,respectively.The improvement in strength was believed to be due to strengthening mechanisms,friction,adiabatic heating,and shock waves.

Effect of strain rate difference between inside and outside groove in M-K model on prediction of forming limit curve of Ti6Al4V at elevated temperatures

The influence of initial groove angle on strain rate inside and outside groove of Ti6Al4V alloy was investigated.Based on the evolution of strain rate inside and outside groove,the effect of strain rate difference on the evolution of normal stress and effective stress inside and outside groove was also analyzed.The results show that when linear loading path changes from uniaxial tension to equi-biaxial tension,the initial groove angle plays a weaker role in the evolution of strain rate in the M-K model.Due to the constraint of force equilibrium between inside and outside groove,the strain rate difference makes the normal stress inside groove firstly decrease and then increase during calculation,which makes the prediction algorithm of forming limit convergent at elevated temperature.The decrease of normal stress inside groove is mainly caused by high temperature softening effect and the rotation of groove,while the increase of normal stress inside groove is mainly due to strain rate hardening effect.

Protective efficacy of an H5/H7 trivalent inactivated vaccine(H5-Re13,H5-Re14, and H7-Re4 strains) in chickens, ducks, and geese against newly detected H5N1, H5N6, H5N8, and H7N9 viruses

Some H5 viruses isolated in poultry or wild birds between 2020 and 2021 were found to be antigenically different from the vaccine strains(H5-Re11 and H5-Re12) used in China. In this study, we generated three new recombinant vaccine seed viruses by using reverse genetics and used them for vaccine production. The vaccine strain H5-Re13 contains the hemagglutinin(HA) and neuraminidase(NA) genes of an H5 N6 virus that bears the clade 2.3.4.4 h HA gene, H5-Re14 contains the HA and NA genes of an H5 N8 virus that bears the clade 2.3.4.4 b HA gene, and H7-Re4 contains the HA and NA genes of H7 N9 virus detected in 2021. We evaluated the protective efficacy of the novel H5/H7 trivalent inactivated vaccine in chickens, ducks, and geese. The inactivated vaccine was immunogenic and induced substantial antibody responses in the birds tested. Three weeks after vaccination, chickens were challenged with five different viruses detected in 2020 and 2021: three viruses(an H5 N1 virus, an H5 N6 virus, and an H5 N8 virus) bearing the clade 2.3.4.4 b HA gene, an H5 N6 virus bearing the clade 2.3.4.4 h HA gene, and an H7 N9 virus. All of the control birds shed high titers of virus and died within 4 days post-challenge, whereas the vaccinated chickens were completely protected from these viruses. Similar protective efficacy against H5 viruses bearing the clade 2.3.4.4 h or 2.3.4.4 b HA gene was observed in ducks and geese. Our study indicates that the newly updated H5/H7 vaccine can provide solid protection against the H5 and H7 N9 viruses that are currently circulating in nature.

Misfit strains inducing voltage decay in LiMn_(y)Fe_(1-y)PO_(4)/C

LiMn_(y)Fe_(1-y)PO_(4) is considered a promising cathode material for next-generation lithium-ion batteries(LIBs) due to its high energy density and low cost. Its energy density degradation is often ascribed to the capacity loss during cycling. However, in this study, we find that the energy density degradation mainly roots in voltage decay. We have synthesized a series of LiMn_(y)Fe_(1-y)PO_(4) /C(0.5 ≤ y ≤ 0.8) and find this voltage decay is correlated with the Mn content. A high amount Mn leads to a heavier voltage decay.In-situ X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM) reveal the nature of this effect, which show a mismatch along the b-axis of-2.68%(charge) and +3.4%(discharge), a volume misfit of-4.41%(charge) and +4.54%(discharge) between Li_(x)Mn_(y)Fe_(1-y)PO_(4) and Mn_(y)Fe_(1-y)PO_(4) during phase transitions. The resultant misfit strains during Li+insertion compared to extraction result in structural degradations, such as amorphization and impurity(Mn F3) accumulation after cycling. The voltage decay can be alleviated by kinetic relaxations and recovered by a wild reannealing. This work demonstrates effective strategies to improve the energy density and cycling performance of LiMn_(y)Fe_(1-y)PO_(4) /C,providing good references for other LIB cathodes, such as the Li-rich cathodes.

Modulation of Schottky barrier in XSi_(2)N_(4)/graphene(X=Mo and W)heterojunctions by biaxial strain

Reducing the Schottky barrier height(SBH)and even achieving the transition from Schottky contacts to Ohmic contacts are key challenges of achieving high energy efficiency and high-performance power devices.In this paper,the modulation effects of biaxial strain on the electronic properties and Schottky barrier of Mo Si_(2)N_(4)(MSN)/graphene and WSi_(2)N_(4)(WSN)/graphene heterojunctions are examined by using first principles calculations.After the construction of heterojunctions,the electronic structures of MSN,WSN,and graphene are well preserved.Herein,we show that by applying suitable external strain to a heterojunction stacked by MSN or WSN—an emerging two-dimensional(2D)semiconductor family with excellent mechanical properties—and graphene,the heterojunction can be transformed from Schottky ptype contacts into n-type contacts,even highly efficient Ohmic contacts,making it of critical importance to unleash the tremendous potentials of graphene-based van der Waals(vd W)heterojunctions.Not only are these findings invaluable for designing high-performance graphene-based electronic devices,but also they provide an effective route to realizing dynamic switching either between n-type and p-type Schottky contacts,or between Schottky contacts and Ohmic contacts.

Plastic Flow Modeling of Ti-5 Al-2 Sn-2 Zr-4 Mo-4 Cr Alloy at Elevated Temperatures and High Strain Rates

The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr（TC17） alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compression tests were carried out with Instron 8874 test machine, while dynamic compression tests were performed with the split Hopkinson pressure bar （SHPB） which was installed with heating device and synchro- assembly system. The dynamic mechanical behaviors tests of TC17 were carded out from room temperature to 800 ℃ at intervals of 200 ℃ and at high sWain rates （5 500-1 9200 s-l）. The stress-strain curves considering temperature-sWain rate coupling actions were obtained. The Johnson-Cook constitutive model was developed through data fitting of the stress-sWain curves. The material constants in the developed constitutive model can be determined using isothermal and adiabatic stress-strain curves at different strain rates. The Johnson-Cook constitutive model provided satisfied prediction of the plastic flow stress for TC17 alloy.

Low-S train and High-Energy KVPO_(4)F Cathode with Multifunctional Stabilizer for Advanced Potassium-Ion Batteries

KVPO_(4)F with excellent structural stability and high operating voltage has been identified as a promising cathode for potassium-ion batteries(PIBs),but limits in sluggish ion transport and severe volume change cause insufficient potassium storage capability.Here,a high-energy and low-strain KVPO_(4)F composite cathode assisted by multifunctional K_(2)C_(4)O_(4)electrode stabilizer is exquisitely designed.Systematical electrochemical investigations demonstrate that this composite cathode can deliver a remarkable energy density up to 530 Wh kg^(-1)with 142.7 mAh g^(-1)of reversible capacity at 25 mA g^(-1),outstanding rate capability of 70.6 mAh g^(-1)at 1000 mA g^(-1),and decent cycling stability.Furthermore,slight volume change(~5%)and increased interfacial stability with thin and even cathode-electrolyte interphase can be observed through in situ and ex situ characterizations,which are attributed to the synergistic effect from in situ potassium compensation and carbon deposition through self-sacrificing K_(2)C_(4)O_(4)additive.Moreover,potassium-ion full cells manifest significant improvement in energy density and cycling stability.This work demonstrates a positive impact of K_(2)C_(4)O_(4)additive on the comprehensive electrochemical enhancement,especially the activation of high-voltage plateau capacity and provides an efficient strategy to enlighten the design of other high-voltage cathodes for advanced high-energy batteries.

The Analysis of Coseismic Response of 4-component Borehole Strainmeters with High Sampling Rate

In this paper,we adopt the observation data of two 10Hz YRY 4-component borehole strainmeters and one 100Hz FBS-3B broadband seismometer to study the responses of their observations to the April 11,2012 MW8. 6 earthquake off the west coast of northern Sumatra,and compare the response characteristics during the coseismic stage after preprocessing of the data. We analyze the spectrum's dynamic process during the coseismic stage with the S transformation method,and discuss the spectrum's details in different seismic phases. The S transformation results of the data of seismometer and borehole strainmeter at the same station show that the coseismic spectrum evolution of the two kinds of observation are similar to each other and can be cross-referenced in indentifying the wave signals,which proves that the borehole strainmeter measurements at high frequencies are reliable.

四川地区YRY-4型钻孔应变观测资料可靠性分析

通过分析钻孔应变观测资料的干扰因素,发现四川地区YRY-4型钻孔应变受季节性降雨、钻孔水位和河水位涨落影响显著。采用钻孔应变自洽检验对钻孔应变仪观测数据进行自检,发现各台应变校正相关系数均大于0.9,说明四川地区YRY-4型应变观测资料的整体质量较高,可以用于区域地震预测和地震科学研究。

二维MoSi_(2)N_(4)/WSe_(2)异质结的第一性原理研究

实验上新合成的MoSi_(2)N_(4)(MSN)由于其独特的七原子层结构和电子特性引起了人们的广泛关注.本文搭建了一种由二维MSN与二维WSe_(2)(WS)垂直堆垛而成的二维MSN/WS异质结并基于第一性原理计算对其电子性质进行了计算,其表现出直接间隙半导体和I型能带排列的特性,具有1.46 eV的带隙.在异质结界面处存在一个由电荷耗尽层MSN指向电荷积累层WS微弱的内建电场.最后,通过施加双轴应变对二维MSN/WS异质结进行调控.发现在正双轴应变的作用下,MSN/WS异质结保持了原来直接带隙半导体和I型能带排列特性;在负双轴应变作用下,MSN/WS异质结由原来的直接带隙半导体转变为间接带隙半导体,当施加的负双轴应变达到-6%与-8%时,I型能带排列转变为Ⅱ型能带排列.

忻州地震监测中心站YRY-4分量钻孔应变仪气压干扰定量识别及特征分析

选取忻州地震监测中心站所辖代县、原平、宁武、繁峙、神池5个子台四分量钻孔应变仪记录数据,采用S变换、回归分析和小波变换等分析方法,对各仪器气压干扰特征进行量化和对比分析。结果表明:气压对钻孔应变观测的影响具有普遍性,气压干扰信号的归一化优势频率分布在0—0.05 Hz;气压干扰系数具有各异性,5个子台2023年3—6月的日变化气压干扰系数分别为-2.5×10^(-9)/hPa、-2.6×10^(-9)/hPa、-1.3×10^(-9)/hPa、-2.1×10^(-9)/hPa、-91.1×10^(-9)/hPa,其中神池子台所受气压干扰程度最高。

发酵行业4-乙烯基愈创木酚和4-乙基愈创木酚研究进展

介绍了4-乙烯基愈创木酚和4-乙基愈创木酚在发酵行业的研究进展,列举了一些有价值的研究实例,指出4-乙烯基愈创木酚和4-乙基愈创木酚是白酒、啤酒(特别是小麦啤酒)、葡萄酒、酱油等产品的重要呈香物质,并从原料、酵母菌种和工艺角度对它们形成的途径和影响因素进行了探讨,提出以分子生物学手段对酵母菌种进行基因克隆是全面提升传统发酵产品质量的关键。

GⅡ-4型诺如病毒体外结合唾液HBGAs受体的检测与分析

目的建立诺如病毒(Norovirus,NoV)结合唾液HBGAs受体的实验方法、验证2株GⅡ-4型NoV毒株与我国人群唾液HBGAs的结合方式。方法收集健康志愿者唾液标本,采用凝集抑制实验法检测唾液中HBGAs血型物质,用EIA法检测NoV VLPs、阳性毒株与HBGAs的结合情况。结果63份标本检出O型21例(占33.3%),B型14例(占22.2%),A型和非分泌型各13例(分别占20.6%),AB型2例(占3.2%)。rVA387、2株GⅡ-4型毒株均能结合分泌型,与非分泌型唾液不反应。结论本研究成功建立了NoV结合唾液HBGAs受体的实验方法,通过NoV毒株与HBGAs相互作用的研究有助于了解NoV的宿主适应特性及病毒进化和流行规律;同时为筛选防治我国人群的抗NoV药物提供技术平台。

Zr-4合金应力松弛过程中的热激活变形与动态应变时效

采用应力松弛实验研究了Zr-4合金的热激活变形与动态应变时效现象.结果表明,合金在应力松弛过程中的塑性变形速率随松弛时间的增加而减小,塑性变形速率和松弛结束时的应力降低比率在623 K附近都会出现最小值.对位错运动的激活体积分析发现,锆合金中位错运动的速率控制机制是位错克服溶质原子的障碍,动态应变时效会导致位错运动的激活体积增大, 623 K附近动态应变时效最为显著,位错密度会对合金的动态应变时效产生影响.

重组大肠杆菌细胞不对称还原4-氯乙酰乙酸乙酯合成(R)-(+)-4-氯-3-羟基丁酸乙酯

从赭色掷孢酵母(Sporobolomyces salmonicolorZJU0105)中克隆出NADPH依赖型醛基还原酶基因,构建了重组大肠杆菌E.coliBL21(pET28-ALR0105),该工程菌可以高效地表达醛基还原酶.将重组细胞用于催化4-氯乙酰乙酸乙酯不对称还原,合成出具有光学活性的(R)-(+)-4-氯-3-羟基丁酸乙酯.实验发现,在加入适量辅酶及辅酶再生酶的条件下,利用重组细胞催化还原反应可以获得比使用赭色掷孢酵母更高的转化率、产率和ee值,得到了几乎是光学纯的(R)-(+)-型产物,从而解决了酵母细胞催化此类反应ee值较低的问题.考察了辅酶及共底物的添加、底物和产物的浓度、pH值、温度以及菌体密度等因素对还原反应的影响.结果表明,不对称还原反应必须在辅酶NADPH和辅酶再生酶系及共底物葡萄糖的参与下进行;底物和高浓度的产物对还原反应有一定的抑制作用;当pH>6.0时,反应的转化率及产率都显著降低;高密度重组细胞可以减小底物的抑制作用.

降解1,2,4-三氯苯的硝基还原假单胞菌J5-1的分离鉴定和邻苯二酚1,2-双加氧酶基因的克隆

从受氯苯污染的土壤中分离到1株以1,2,4-三氯苯为唯一碳源生长的细菌,命名为J5-1.根据其生理生化特征和16SrDNA(GenBank Accession No.EF107515)序列相似性分析,将该菌株初步鉴定为硝基还原假单胞菌(Pseudomonas nitroreducens).当1,2,4-三氯苯初始浓度为400 mg/L时,J5-1对其最大降解率接近90%;当1,2,4-三氯苯浓度初始为20 mg/L时,降解效果最好.J5-1对1,2,4-TCB的降解服从一级反应动力学.从J5-1的基因组DNA中克隆到CC12O的全长序列.

莱茵衣藻Nfr-4突变株中类胡萝卜素含量的变化及其对藻生长的影响

文章对相同条件下培养的莱茵衣藻野生型CC-137和八氢番茄红素脱氢酶(phytoene desaturase,PDS)基因突变株Nfr-4的生长进行分析;并用反相高效液相色谱分析总有色类胡萝卜素以及叶绿素含量变化,结果表明两者生长的差异明显;Nfr-4突变株的单细胞叶绿素和总有色类胡萝卜素含量高于野生型CC-137的。