聚醚有机硅表面活性剂与经典阴离子表面活性剂复配体系

聚醚有机硅表面活性剂因其良好的表面活性近年来受到广泛关注。为了进一步扩展其下游应用空间,开发复合表面活性剂配方,文章将一种寡聚醇聚醚三硅氧烷表面活性剂与经典阴离子表面活性剂(烷基糖苷磺酸盐和醇醚磷酸盐)复配,详细探究了二元表面活性剂混合体系的混合吸附参数和混合胶束参数。随后围绕精选的复配比例,对二元表面活性剂的分散(泡沫、乳液、悬浮液)性能在常见模型体系中进行了初步探究,为聚醚硅表面活性剂体系的应用开发提供了重要的基础参考。

肉鸡Trx1和Trx2蛋白的表达纯化及其抗氧化应激效果评价

试验旨在对肉鸡Trx1和Trx2蛋白进行表达和纯化,并评价其抗氧化特性。将原核表达载体GgTrx1-pET28a(+)和GgTrx2-nsp-pET28a(+)转入大肠埃希菌中进行蛋白表达;应用镍柱亲和层析的方法对该融合蛋白进行纯化;采用胰岛素还原法对重组肉鸡Trx1和Trx2蛋白(GgTrx1和GgTrx2)进行活性鉴定;通过细胞体外试验分析比较GgTrx1和GgTrx2对大鼠肝细胞BRL-3A氧化应激保护作用的影响。结果显示,试验成功获得两种重组蛋白:GgTrx1和GgTrx2,最适诱导条件分别为37℃、0.4mmol/L IPTG诱导4h和37℃、1.0mmol/L IPTG诱导4h;纯化的重组蛋白GgTrx1和GgTrx2纯度可达到90%,浓度分别达到4.0和5.0 mg/mL。重组蛋白GgTrx1和GgTrx2均具有较高的还原胰岛素二硫键的能力,并呈现出浓度效应。体外细胞试验发现,重组蛋白GgTrx1和GgTrx2均能显著降低过氧化氢诱导的BRL-3A膜脂过氧化,保护抗氧化酶SOD和CAT活性,且重组蛋白GgTrx2效果更明显。本试验结果表明,重组蛋白GgTrx1和GgTrx2均具有生物学活性和良好的抗氧化应激特性,且线粒体型Trx2为临床治疗氧化应激性疾病提供了更多可能。

Changes in gut microbiota composition and diversity associated with post-cholecystectomy diarrhea

BACKGROUND Post-cholecystectomy diarrhea(PCD)frequently occurs in patients following gallbladder removal.PCD is part of the post-cholecystectomy(PC)syndrome,and is difficult to treat.After cholecystectomy,bile enters the duodenum directly,independent of the timing of meals.The interaction between the bile acids and the intestinal microbes is changed.Therefore,the occurrence of PCD may be related to the change in microbiota.However,little is known about the relationship between the gut microbiota and PCD.AIM To better understand the role of the gut microbiota in PCD patients.METHODS Fecal DNA was isolated.The diversity and profiles of the gut microbiota were analyzed by performing high-throughput 16S rRNA gene sequencing.The gut microbiota were characterized in a healthy control(HC)group and a PC group.Subsequently,the PC group was further divided into a PCD group and a postcholecystectomy non-diarrhea group(PCND)according to the patients’clinical symptoms.The composition,diversity and richness of microbial communities were determined and compared.RESULTS In the PC and HC groups,720 operational taxonomic units(OTUs)were identified.The PC group had fewer OTUs than the HC group.β-diversity was decreased in the PC group.This indicated decreased microbial diversity in the PC group.Fifteen taxa with differential abundance between the HC and PC groups were identified.In the PCD group compared to the PCND group,significant decreases in microbial diversity,Firmicutes/Bacteroidetes ratio,and richness of probiotic microbiota(Bifidobacterium and Lactococcus),and an increase in detrimental microbiota(Prevotella and Sutterella)were observed.Moreover,a negative correlation was found between Prevotella and Bifidobacterium.Using a Kyoto Encyclopedia of Genes and Genomes functional analysis,it was found that the abundances of gut microbiota involved in lipid metabolism pathways were markedly lower in the PCD group compared to the PCND group.CONCLUSION This study demonstrated that gut dysbiosis may play a critical role in PCD,which provides new insights into therapeutic options for PCD patients.

Intestinal T-cell lymphomas:A retrospective analysis of 68 cases in China

AIM: To investigate the clinical features, diagnosis, treatment and prognosis of intestinal T-cell lymphomas (ITCL) by retrospective analysis.

Effects of Sr on the microstructure,tensile and creep properties of AZ61-0.7Si magnesium alloy

The modification and refinement of Mg2Si phase is thought to be one of the key aspects to improve the mechanical properties of Si-containing magnesium alloys. In this article, the effects of Sr on the microstructure, tensile and creep properties of AZ61-0.7Si magnesium alloy were investigated. The results indicate that adding small amounts of Sr to AZ61-0.7Si alloy can modify and refine Chinese script shaped Mg2Si phases in the alloy. After adding 0.03wt%-0.09wt% Sr to AZ61-0.7Si alloy, the Mg2Si phases in the alloy change from the coarse Chinese script shape to fine granule and/or irregular polygonal shapes. The modification and refinement mechanisms of Mg2Si phases in Sr-containing AZ61-0.7Si alloys are possibly related to the reduction of growth rate and the enhancement of nucleation ratio for Mg2Si particles during the solidification process. Owing to the modification and refinement of Mg2Si phases, the tensile and creep properties of Sr-containing AZ61-0.7Si alloys are greatly improved.

Effects of heat treatment on the microstructure and mechanical properties of ZA84 magnesium alloy

The effects of heat treatment on the microstructure and mechanical properties of ZA84 （Mg-8Zn-4Al-0.25Mn） alloy were investigated. The results indicate that the as-cast microstructure of the alloy is mainly composed of α-Mg matrix and two different morphologies of precipitates （continuous and quasi-continuous Mg32（Al,Zn）49 phases and isolated Mg5Al2Zn2 phases）. After solid solution treatment at 345℃, the Mg32（Al,Zn）49 phases change from continuous and quasi-continuous net to disconnected acute angle shape, and parts of second phases sphericize. The optimum heat treatment condition for the alloy is solution treatment at 345℃ for 48 h and water quenching, then aging treatment at 200℃ for 12 h and atmosphere cooling. Under the optimum condition, the ulti- mate tensile strength and yield strength of the alloy can be imoroved, but the elongation is not effected much bv heat treatment.

A Fair Blind Signature Scheme to Revoke Malicious Vehicles in VANETs

With the rapid development of IoT(Internet of Things),VANETs(Vehicular Ad-Hoc Networks)have become an attractive ad-hoc network that brings convenience into people’s lives.Vehicles can be informed of the position,direction,speed and other real-time information of nearby vehicles to avoid traffic jams and accidents.However,VANET environments could be dangerous in the absence of security protection.Because of the openness and self-organization of VANETs,there are plenty of malicious pathways.To guarantee vehicle security,the research aims to provide an effective VANET security mechanism that can track malicious vehicles as necessary.Therefore,this work focuses on malicious vehicles and proposes an anonymous authentication scheme in VANETs based on the fair blind signature to protect vehicle security.

Kunming mouse strain is less susceptible to elastase-induced abdominal aortic aneurysms

Background:Porcine pancreatic elastase(PPE)is successfully used to induce abdominal aortic aneurysm(AAA)in mice.However,differences between mouse strains in susceptibility to PPE induction have been reported.Kunming mouse is one of the most frequently used strains in China but whether it is suitable for induction of AAA by PPE application remains unclear.Methods:PPE infusion(1.5 units/ml)in temporary controlled aorta was performed to induce AAAs in both C57BL/6J and Kunming mice.Phosphatebuffered saline(PBS)application was used as vehicle control.The aorta diameters of all mice were measured at days 0 and 14 after surgery to evaluate the AAA formation.Results:After 14 days of PPE or PBS infusion,all mice were sacrificed and aorta tissues were collected for histological staining analysis.At the 14th day after infusion,PPE successfully induced aortic dilation in Kunming mice and typical AAA in C57BL/6J mice.The aorta diameter increased by 0.23 mm in Kunming mice after PPE infusion,while it was 0.72 mm in the C57BL/6J strain.PPE induced mild elastin degradation,smooth muscle cell(SMC)depletion and mural leucocyte infiltration in Kunming mice,but in PPE-sensitive C57BL/6J mice,it induced total loss of SMCs,elastin disappearance and diffused infiltrated leucocytes in aortic aneurysmal segments.The effects of PPE in inducing angiogenesis and upregulating matrix metalloproteinase 2 and 9 expression in Kunming mice were also weaker than that in C57BL/6J mice.Conclusion:At the reported dose of PPE,Kunming mouse is not as susceptible to AAA formation as C57BL/6J mice.The failure of PPE to induce AAA formation in Kunming mice may be associated to its inability to boost a strong inflammatory response.

A Novel Anonymous Authentication Scheme Based on Edge Computing in Internet of Vehicles

The vehicular cloud computing is an emerging technology that changes vehicle communication and underlying trafc management applications.However,cloud computing has disadvantages such as high delay,low privacy and high communication cost,which can not meet the needs of realtime interactive information of Internet of vehicles.Ensuring security and privacy in Internet of Vehicles is also regarded as one of its most important challenges.Therefore,in order to ensure the user information security and improve the real-time of vehicle information interaction,this paper proposes an anonymous authentication scheme based on edge computing.In this scheme,the concept of edge computing is introduced into the Internet of vehicles,which makes full use of the redundant computing power and storage capacity of idle edge equipment.The edge vehicle nodes are determined by simple algorithm of dening distance and resources,and the improved RSA encryption algorithm is used to encrypt the user information.The improved RSA algorithm encrypts the user information by reencrypting the encryption parameters.Compared with the traditional RSA algorithm,it can resist more attacks,so it is used to ensure the security of user information.It can not only protect the privacy of vehicles,but also avoid anonymous abuse.Simulation results show that the proposed scheme has lower computational complexity and communication overhead than the traditional anonymous scheme.

Activation pressure studies with an iron-based catalyst for slurry Fischer-Tropsch synthesis

Fischer-Tropsch synthesis （FTS） was carried out with an industrial iron-based catalyst （100Fe/5Cu/6K/16SiO2, by weight） under the baseline conditions in a stirred tank slurry reactor （STSR）. The effects of activation pressure on the catalyst activity and selectivity were investigated. It was found that iron phase compositions, textural properties, and FTS performances of the catalysts were strongly dependent on activation pressure. The high activation pressure retards the carburization. MФssbauer effect spectroscopy （MES） results indicated that the contents of the iron carbides clearly decrease with the increase of activation pressure, especially for the activation pressure increasing from 1.0 MPa to 1.5 MPa, and the reverse trend is observed for superparamagnetic Fe^3＋ （spm）. The higher content of Fe^3＋ （spm） results in the higher amount of CO2 in tail gas when the catalyst is reduced at higher pressure. The catalyst activity decreases with the increase of activation pressure. The high quantity of iron carbides is necessary to obtain high FTS activity. However, the activity of the catalyst activated in syngas can not be predicted solely from the fraction of the carbides. It is concluded that activation with syngas at the lower pressure would be the most desirable for the better activity and stability on the iron-based catalyst.

Isothermal Kinetics Modelling of the Fischer-Tropsch Synthesis over the Spray-Dried Fe-Cu-K Catalyst

The isothermal kinetics of the Fischer-Tropsch synthesis （FTS） over Fe-Cu-K spray-dried catalyst was studied in a spinning basket reactor. The experiments were carried out at a constant temperature of 523 K, n（H2）/n（CO） feed ratios of 0.8 2.0, reactor pressures of 1.1 2.5 MPa, and space velocity of 0.556× 10^-3 Nm^3/kgcat·s. Kinetic model for hydrocarbon formation was derived on the basis of simplified carbide mechanism to reduce the number of parameters. Two individual rate constants for methane and ethene were considered. Furthermore, the model was modified empirically by non-intrinsic effect, such as physisorption and fictitious olefin pressures that were taken into account, and the influences of secondary reaction of α-olefins on product distribution. The simulation results showed that the experimental phenomena of FTS and the deviations from ASF distribution, such as the relatively high yield of methane and low yield of ethene observed experimentally could be depicted basically.

不同酯化度烷基糖苷磺基琥珀酸酯盐的合成与性能

运用两步法合成了四种不同酯化度的烷基葡萄糖苷磺基琥珀酸酯盐产品(APGSS)。通过探究时间和反应摩尔比对APGSS收率的影响,确定了不同酯化度APGSS的最佳合成工艺条件。同时探究了不同酯化度APGSS的泡沫性能、乳化性能和润湿性能。结果表明:无论在蒸馏水和硬水中,APGSS的起泡性能均随酯化度的增加而减小,泡沫稳定性能均优于烷基糖苷(APG);APGSS对油脂类大豆油的乳化性能均优于对矿物油类液体石蜡的乳化性能;随着酯化度的增加,润湿性能逐渐减弱。

Hepatic transcriptome signatures in mice and humans with nonalcoholic fatty liver disease

Background:Nonalcoholic fatty liver disease(NAFLD)is the main reason for cirrhosis and hepatocellular carcinoma.As a starting point for NAFLD,the treatment of nonalcoholic fatty liver(NAFL)is receiving increasing attention.Mice fed a high-fat diet(HFD)and hereditary leptin deficiency(ob/ob)mice are important NAFL animal models.However,the comparison of these mouse models with human NAFL is still unclear.Methods:In this study,HFD-fed mice and ob/ob mice were used as NAFL animal models.Liver histopathological characteristics were compared,and liver transcriptome from both mouse models was performed using RNA sequencing(RNA-seq).RNAseq data obtained from the livers of NAFL patients was downloaded from the GEO database.Global gene expression profiles in the livers were further analyzed using functional enrichment analysis and the Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway.Results:Our results showed that the biochemical parameters of both mouse models and human NAFL were similar.Compared with HFD-fed mice,ob/ob mice were more similar in histologic appearance to NAFL patients.The liver transcriptome characteristics partly overlapped in mice and humans.Furthermore,in the NAFL pathway,most genes showed similar trends in mice and humans,thus demonstrating that both types of mice can be used as models for basic research on NAFL,considering the differences.Conclusion:Our findings show that HFD-fed mice and ob/ob mice can mimic human NAFL partly in pathophysiological process.The comparative analysis of liver transcriptome profile in mouse models and human NAFL presented here provides insights into the molecular characteristics across these NAFL models.

高效液相色谱法测定醇醚羧酸盐中羟基乙酸、一氯乙酸和二氯乙酸的含量

建立了一种高效液相色谱法测定醇醚羧酸盐产品中羟基乙酸、一氯乙酸和二氯乙酸含量的方法。样品经流动相溶解后直接进样分析,采用具有反相和阴离子交换两种分离模式的Acclaim Trinity P1色谱柱(3.0 mm×150 mm,3μm)进行分离,以体积分数为10%乙腈-90%磷酸缓冲盐水溶液(10 mmol磷酸二氢钠,调节pH为5.0)洗脱,在紫外检测器210 nm波长下检测。经方法学验证,3种化合物在一定质量浓度范围内线性良好,相关系数均大于0.999,测定精密度、稳定性皆满足要求,测定平均回收率在96%~98%之间,相对标准偏差(RSD)皆小于3%。与GB/T 28193-2011《表面活性剂中氯乙酸(盐)残留量的测定》方法相比,该方法测定结果接近,但增加了羟基乙酸的测定,结果更加全面。与离子色谱法相比,该方法不受产品溶解性限制,可用于高碳链或水溶性不佳的产品体系,适用范围更宽。

Predicting the evolution of photospheric magnetic field in solar active regions using deep learning

The continuous observation of the magnetic field by the Solar Dynamics Observatory(SDO)/Helioseismic and Magnetic Imager(HMI)produces numerous image sequences in time and space.These sequences provide data support for predicting the evolution of photosphericmagnetic field.Based on the spatiotemporal long short-term memory(LSTM)network,we use the preprocessed data of photospheric magnetic field in active regions to build a prediction model for magnetic field evolution.Because of the elaborate learning and memory mechanism,the trained model can characterize the inherent relationships contained in spatiotemporal features.The testing results of the prediction model indicate that(1)the prediction pattern learned by the model can be applied to predict the evolution of new magnetic field in the next 6 hours that have not been trained,and predicted results are roughly consistent with real observed magnetic field evolution in terms of large-scale structure and movement speed;(2)the performance of the model is related to the prediction time;the shorter the prediction time,the higher the accuracy of the predicted results;(3)the performance of themodel is stable not only for active regions in the north and south but also for data in positive and negative regions.Detailed experimental results and discussions on magnetic flux emergence and magnetic neutral lines finally show that the proposed model could effectively predict the large-scale and short-term evolution of the photospheric magnetic field in active regions.Moreover,our study may provide a reference for the spatiotemporal prediction of other solar activities.

A Survey on Cryptographic Security and Information Hiding Technology for Cloud or Fog-Based IoT System

Internet of Things(IoT)is an emerging paradigm involving intelligent sensor networks that incorporates embedded technology for collecting data,communicating with external environments.Recently,cloud computing together with fog computing has become an important research area of the Internet of Things because of big data processing capabilities.It is a promising technology that utilizes cloud or fog computing/architecture to improve sensor computing,storage,and communication capabilities.However,recently it has been shown that this computing/architecture may be vulnerable to various attacks because of the openness nature of the wireless network.Therefore,it becomes more and more important to ensure the security and privacy in these scenes.Encryption security and information hiding technology can provide authentication,confidentiality,integrity,anti-eavesdropping,availability and so on for these computing models or architectures.The purpose of this review is to look for original articles with novel ideas and solutions to address encryption security and information hiding technologies in cloud or fog-based Internet of Things systems.We hope this review will provide an opportunity for scientists,researchers and industry engineers to study original manuscripts and know developments in all aspects of security,privacy,trust,and covert communication issues in cloud or fog computing/architecture Internet of Things systems.

昆虫共生微生物在病虫害和疾病控制上的应用前景

昆虫与微生物之间的互利共生关系是自然界中一种常见的互作形式。昆虫的种类丰富多样并且在自然界中分布广泛,在一定程度上得益于共生微生物的帮助。随着生物技术的不断发展,越来越多的共生微生物和互利共生模式得以发现并深入研究。微生物不仅能够为昆虫的生长发育提供营养,还能合成很多生物活性物质、调节宿主的免疫、对抗捕食者和抵御病原微生物感染,成为宿主昆虫健康和适应的守护者。鉴于共生微生物与昆虫生理生态的密切联系,以及昆虫对人类经济与健康的重要影响,利用共生微生物对昆虫及虫媒病进行生物控制已经成为一个热点研究方向,并展现了良好的应用前景。本文对昆虫共生微生物的多样性、生物学功能、与宿主相互作用机制及其在病虫害和虫媒病防治中的研究进展进行综述和展望。

Numerical simulations of solidification and hot tearing for continuous casting of duplex stainless steel

Hot tearing is one of the major defects in continuous casting of steels, which severely limits the productivity of steelmaking processes. To further understand the defect, the problem of hot tearing in duplex stainless steel produced by a vertical continuous caster was investigated. A three-dimensional heat transfer and elastic-plastic model was developed based on the realistic roller layout in continuous slab casting, using ProCAST software. According to the hot tearing indicator criterion, the influence of operating parameters on the hot tearing susceptibility was evaluated. The results show that the surface temperature distribution is not sensitive to the superheat. The center of wide surface shell at the mold exit is the thinnest, and the thickness is about 10.52 mm at the superheat temperature of 40 -C. The hot tearing mainly concentrates on the slab solidification front and near the narrow face. However, corner cracks are prone to appear near the corner. With the increase in casting speed and the decrease in the cooling intensity in the secondary cooling zone, the solidification end point is rushed, which leads to the position of hot tearing lowering accordingly.

电子轴向拉伸提升贫氧环境海水电池性能

长寿命溶解氧海水电池是深远海观测能源网络的重要组成单元,但海水贫氧复杂环境对设计高性能氧还原催化剂提出了重要挑战.本文以酞菁铁为模型催化剂,通过理论计算与实验验证,提出了活性位点电子轴向拉伸可大幅提升催化剂在极端贫氧环境中的氧还原活性和稳定性.该研究为构建高性能海水电池提供了材料学解决方案,同时为极端环境下催化剂的变革性设计提供了新的思路.