Allelic Polymorphism,Gene Duplication and Balancing Selection of MHC Class ⅡB Genes in the Omei Treefrog(Rhacophorus omeimontis)

The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major histocompatibility complex（MHC） class Ⅱ molecules, the characterization and the evolution of amphibian MHC class Ⅱ genes have attracted increasing attention. The polymorphism of MHC class Ⅱ genes was found to be correlated with susceptibility to fungal pathogens in many amphibian species, suggesting the importance of studies on MHC class Ⅱ genes for amphibians. However, such studies on MHC class Ⅱ gene evolution have rarely been conducted on amphibians in China. In this study, we chose Omei treefrog（Rhacophorus omeimontis）, which lived moist environments easy for breeding bacteria, to study the polymorphism of its MHC class Ⅱ genes and the underlying evolutionary mechanisms. We amplified the entire MHC class ⅡB exon 2 sequence in the R. omeimontis using newly designed primers. We detected 102 putative alleles in 146 individuals. The number of alleles per individual ranged from one to seven, indicating that there are at least four loci containing MHC class ⅡB genes in R. omeimontis. The allelic polymorphism estimated from the 102 alleles in R. omeimontis was not high compared to that estimated in other anuran species. No significant gene recombination was detected in the 102 MHC class ⅡB exon 2 sequences. In contrast, both gene duplication and balancing selection greatly contributed to the variability in MHC class ⅡB exon 2 sequences of R. omeimontis. This study lays the groundwork for the future researches to comprehensively analyze the evolution of amphibian MHC genes and to assess the role of MHC gene polymorphisms in resistance against extracellular pathogens for amphibians in China.

Short-Term Mindfulness Intervention on Adolescents’ Negative Emotion under Global Pandemic

Objective:In this research,we tried to explore how short-term mindfulness(STM)intervention affects adoles-cents’anxiety,depression,and negative and positive emotion during the COVID-19 pandemic.Design:10 classes were divided into experiment groups(5 classes;n=238)and control(5 classes;n=244)randomly.Hospital Anxi-ety and Depression Scale(HADS)and Positive and Negative Affect Schedule(PANAS)were used to measure par-ticipants’dependent variables.In the experiment group,we conducted STM practice interventions every morning in theirfirst class from March to November 2020.No interventions were conducted in the control group.Methods:Paired-sample t-tests were used to identify if a significant difference exists between every time point of the experimental and control groups.Repeated ANOVA and Growth Mixture Model(GMM)were used to analyze the tendency of positive and negative emotions,anxiety,and depression in the experimental group.Results and Conclusions:(1)With the intervention of STM,there was a significant decrease in negative emotions and an increase in positive emotions in the experimental group,whereas there were non-significant differences in the control group.(2)To explore the heterogeneity trajectories of dependent variables,we built a GMM and found there were two latent growth classes in the trajectories.(3)The results of the models showed their trajec-tories were downward,which meant that the levels of anxiety,depression,and negative emotions of participants decreased during the STM training period.Nonetheless,the score of positive affect showed upward in three loops of intervention,which indicated that the level of the participants’positive affect increased through the STM inter-vention.(4)This research indicated that STM should be given increasing consideration to enhance mental health during the worldwide outbreak of COVID-19.

细水雾扑灭B类火的全尺度实验

根据IMO有关测试规范的要求,进行了一系列全尺度动力机舱模拟灭火实验.实验中采用的是局部保护细水雾灭火系统,通过改变通风条件、预燃时间、喷雾方式及火焰功率等因素,考察了它们对系统灭火有效性的影响.实验结果表明,细水雾系统可有效扑灭动力机舱内设定的各种工况下的油池火和油雾火,与气体灭火系统相比,受通风条件影响小,能有效降低室内温度及CO、CO2浓度,因而系统工作期间消防人员和操作人员可安全进入.在油池火灭火实验中发现通过火焰冷却灭火时所需时间较短,而依靠燃料表面冷却灭火时则时间较长.此外研究结果还显示,采用侧喷方式时,系统的灭火性能将大大提高,而较长的预燃时间则有利于细水雾扑灭油雾火.

Scavenger receptor BI: A multi-purpose player in cholesterol and steroid metabolism

Scavenger receptor class B type Ⅰ (SR-BI) is an important member of the scavenger receptor family of integral membrane glycoproteins. This review highlights studies in SR-BI knockout mice, which concern the role of SR-BI in cholesterol and steroid metabolism. SR-BI in hepatocytes is the sole molecule involved in selective uptake of cholesteryl esters from high-density lipoprotein (HDL). SR-BI plays a physiological role in binding and uptake of native apolipoprotein B (apoB)-containing lipoproteins by hepatocytes, which identif ies SR-BI as a multipurpose player in lipid uptake from the blood circulation into hepatocytes in mice. In adrenocortical cells, SR-BI mediates the selective uptake of HDL-cholesteryl esters, which is eff iciently coupled to the synthesis of glucocorticoids (i.e. corticosterone). SR-BI knockout mice suffer from adrenal glucocorticoid insuff iciency, which suggests that functional SR-BI protein is necessary for optimal adrenal steroidogenesis in mice. SR-BI in macrophages plays a dual role in cholesterol metabolism as it is able to take up cholesterol associated with HDL and apoBcontaining lipoproteins and can possibly facilitate cholesterol efflux to HDL. Absence of SR-BI is associated with thrombocytopenia and altered thrombosis susceptibility, which suggests a novel role for SR-BI in regulating platelet number and function in mice. Transgenic expression of cholesteryl ester transfer protein in humanized SR-BI knockout mice normalizes hepatic delivery of HDL-cholesteryl esters. However, other pathologies associated with SR-BI def iciency, i.e. increased atherosclerosis susceptibility, adrenal glucocorticoid insuffi ciency, and impaired platelet function are not normalized, which suggests an important role for SR-BI in cholesterol and steroid metabolism in man. In conclusion, generation of SR-BI knockout mice has signif icantly contributed to our knowledge of the physiological role of SR-BI. Studies using these mice have identif ied SR-BI as a multi-purpose player in cholesterol and steroid metabolism because it has distinct roles in reverse cholesterol transport, adrenal steroidogenesis, and platelet function.

Biliary cholesterol secretion: More than a simple ABC

Biliary cholesterol secretion is a process important for 2 major disease complexes, atherosclerotic cardiovascular disease and cholesterol gallstone disease. With respect to cardiovascular disease, biliary cholesterol secretion is regarded as the f inal step for the elimination of cholesterol originating from cholesterol-laden macrophage foam cells in the vessel wall in a pathway named reverse cholesterol transport. On the other hand, cholesterol hypersecretion into the bile is considered the main pathophysiological determinant of cholesterol gallstone formation. This review summarizes current knowledge on the origins of cholesterol secreted into the bile as well as the relevant processes and transporters involved. Next to the established ATP-binding cassette (ABC) transporters mediating the biliary secretion of bile acids (ABCB11), phospholipids (ABCB4) and cholesterol (ABCG5/G8), special attention is given to emerging proteins that modulate or mediate biliary cholesterol secretion. In this regard, the potential impact of the phosphatidylserine flippase ATPase class Ⅰ type 8B member 1, the Niemann Pick C1-like protein 1 that mediatescholesterol absorption and the high density lipoprotein cholesterol uptake receptor, scavenger receptor class B type Ⅰ, is discussed.

Upregulation of caveolin-1 and SR-B1 in mice with non-alcoholic fatty liver disease

BACKGROUND:Non-alcoholic fatty liver disease(NAFLD)is one of the most frequent causes of liver diseases,with markedly increased prevalence.However,its mechanisms are not clear.The present study was undertaken to illustrate the role of caveolin-1(cav1)and the scavenger receptor class B type 1(SR-B1)in NAFLD.METHODS:Adult male C57BL/6 mice were fed with a normal diet or high fat and cholesterol(HFC)diet for 14 weeks.The mice were sacrificed to collect plasma and harvest the liver;their plasma lipid concentration was measured.Hepatic cav1and SR-B1 mRNA and protein expression were determined by real-time quantitative polymerase chain reaction(qPCR)and Western blotting,respectively.In order to study cav1 and SR-B1distribution and change in hepatocytes,immunohistochemical analysis was performed.RESULTS:HFC diet increased plasma lipids,induced NAFLD and increased the liver/body weight ratio.Compared to the control mice(n=6),the mRNA and protein levels of cav1 and SR-B1 in liver tissue of the NAFLD mice(n=12)increased significantly(cav1 mRNA:1.536±0.226 vs 0.980±0.272,P【0.05;protein:0.643±0.240 vs 0.100±0.130,P【0.01;SR-B1 mRNA:1.377±0.125 vs 0.956±0.151,P【0.01;protein:2.156±0.507vs 0.211±0.211,P【0.01).Furthermore,both cav1 and SR-B1immunoreactivity increased and their distribution was also changed,mainly in the plasma membrane of hepatocytes,cytoplasm and membrane of lipid droplets and around.CONCLUSION:NAFLD is associated with increased concentration of plasma lipids and upregulation of hepatic cav1 and SR-B1 gene and protein expressions,which indicate that cav1 and SR-B1 might play crucial roles in the pathogenesis of NAFLD.

手提式六氟丙烷灭火器灭B类火能力研究

从燃油燃烧的化学反应、燃烧过程的能量方程方面,分析了影响六氟丙烷灭火器灭B类火结果的因素,介绍了六氟丙烷灭火器灭B类火的实际情况。分别按照国际标准、中国国家标准对六氟丙烷灭火器灭B类火能力作出了判断。

不同气源压缩气体泡沫灭B类火灾性能比较

采用实验室压缩气体泡沫系统,通过油盘火对比试验,分别考察基于不同气源的压缩气体泡沫对于120#溶剂油火灾的灭火性能,分析探讨适用于常规B类火灾扑救的气源类型和供气方案。结果表明,在泡沫溶液供给强度为2.5 L/(min.m2)的条件下,压缩氮气泡沫和压缩空气泡沫均可扑灭120#溶剂油火灾,都具有良好的抗烧和抗复燃性能;压缩氮气泡沫比压缩空气泡沫的控灭火性能略有提升,但二者差别不大;对于常规B类非极性燃料火灾,实际工程中有氮气源的场所建议直接采用已有供氮气设备作为供气源。

Susceptibility gene for stroke or cerebral infarction in the Han population in Hunan Province of China

The scavenger receptor class B type I gene can protect against atherosclerosis; a mononucleotide polymorphism is associated with differences in blood lipid metabolism, postprandial serum lipid levels, insulin resistance, coronary artery disease and familial hyperlipidemia. In this study, the scavenger receptor class B type I gene exon 1 G4A gene polymorphism in atherosclerotic cerebral infarction patients, cerebral hemorrhage patients and normal controls was detected using the polymerase chain reaction-restriction fragment length polymorphism method. The results showed that the GA ＋ AA genotype frequency of scavenger receptor class B type I gene G4A in atherosclerotic cerebral infarction patients was similar to that in cerebral hemorrhage patients and normal controls; however, the A allele frequency was significantly lower than that in normal controls. The serum level of high-density lipoprotein cholesterol in patients with the scavenger receptor class B type I gene G4A GA ＋ AA genotype was significantly higher, while the serum level of low-density lipoprotein cholesterol was significantly lower than that in patients with the GG genotype, in both the atherosclerotic cerebral infarction and cerebral hemorrhage groups. The serum level of high-density lipoprotein cholesterol in patients with the scavenger receptor class B type I gene G4A GA ＋ AA genotype was significantly higher, while the serum levels of low-density lipoprotein cholesterol and total cholesterol were significantly lower than those in normal controls with the GG genotype. Our experimental results suggest that the G4A polymorphism of the scavenger receptor class B type I gene is a possible predisposing risk factor for atherosclerotic cerebral infarction, and that it has no association with cerebral hemorrhage in the Hart population in Hunan province of China. The A allele is possibly associated with the metabolism of high-density and low-density lipoprotein cholesterol.

干粉灭火剂灭B类火标准试验方法探讨

介绍了国内外使用的干粉灭 B类火的典型方法及其优缺点分析 ,重点论述了现行国家标准及国际标准化组织ISO所采用的方法及几种改进方案 ,对修订干粉灭火剂国家标准有一定的参考价值。

Single amino acid mutation of SR-BI decreases infectivity of hepatitis C virus derived from cell culture in a cell culture model

AIM To investigate the effect of a single amino acid mutation in human class B scavenger receptor I(SR-BI) on the infectivity of cell culture-derived hepatitis C virus(HCVcc) in SR-BI knock-down Huh7-si SR-BI cells.METHODS Site-directed mutagenesis was used to construct the SR-BI S112 F mutation,and the mutation was confirmed by nucleotide sequencing. SR-BI knock-down Huh7-si SR-BI cells were transfected with SR-BI S112 F,SR-BI wild type(WT) and control plasmids,and then infected with HCVpp(HCV pseudoparticles) and hepatitis C virus derived from cell culture(HCVcc). A fluorescence assay was performed to analyze the effect of the S112 F mutation on HCV entry; quantitative real-time PCR,immunofluorescence,and Western blot assays were used to analyze the effect of the S112 F mutation on HCV infectivity. CHO cells expressing WT and SRBI S112 F were incubated with the HCV E2 protein expressed in HEK 293 T cells,and flow cytometry was performed to examine the ability of SR-BI S112 F to bind to the HCV E2 protein. Huh7-si SR-BI cells were transfected with SR-BI WT and the S112 F mutant,andthen Di I-HDL was added and images captured under the microscope to assess the ability of SR-BI S112 F to take up HDL.RESULTS The SR-BI S112 F mutation was successfully constructed. The S112 F mutation decreased the expression of the SR-BI m RNA and protein. SR-BI S112 F decreased HCV entry and HCVcc infectivity in Huh7-si SR-BI cells. The S112 F mutation impaired the binding of SR-BI to HCV E2 protein and decreased the HDL uptake of SR-BI.CONCLUSION The S112 F single amino acid mutation in SR-BI decreased the levels of the SR-BI m RNA and protein,as well as the ability of SR-BI to bind to the HCV E2 protein. Amino acid 112 in SR-BI plays important roles in HCV entry and the infectivity of HCVcc in vitro.

手提式灭火器灭B类火性能标准确认方法

对沿用了几十年的、国际通用的手提式灭火器灭B类火性能的标准确认方法提出了异议,分析了其中存在的问题及给社会消防安全带来的隐患和风险。由此提出进行以"人机分离"和不进行点火灭火试验为特征的"手提式灭火器灭B类火试验的等效试验方法"研究的必要性和可行性。

复合B级材料建筑保温结构一体化技术防火设计应用对策研究与建议

近20年间,建筑保温材料应用已成为我国建筑节能工作必不可少的重要环节。随着国家标准《建筑设计防火规范》GB50016不断修订完善,建筑外墙保温系统防火设计尤其是针对采用B1级、B2级有机保温材料的防火设计工程应用可谓一波三折。结合近10年来广泛应用的夹芯B级保温材料类现浇混凝土一体化技术体系、复合夹芯B级保温材料免拆外模板一体化技术体系和夹芯B级保温材料复合砌块自保温墙体一体化技术体系3大体系,分别从其不同的建筑保温系统构造特征、材料构造复合方式和防火设计应用特点,并结合《建筑设计防火规范》GB50016具体条文,对其进行对比性分析研究,提出了各自的工程应用注意要点、行业争议焦点和发展应用对策建议。

Sub-Epithelial Connective Tissue Graft to Increase the Volume of Residual Alveolar Bone in the Upper Anterior Sector and Fixed Rehabilitation with Zirconia

Background: The collapse of the alveolar ridge in an edentulous area in patients who will undergo oral rehabilitation impedes the harmonic relationship between pontic and ridge. To correct this type of defect there are several surgical techniques that aim to achieve soft tissue augmentation, allowing the conformation of an ideal profile with the use of a pontic. The aim was to demonstrate how the technique of tissue modification in an area with a class b defect of Allen allows the correction of aesthetics in the anterior dental sector. Case presentation: A 41-year-old Mexican woman. Extra and intraoral examination was performed, the dental treatment included connective tissue graft and rehabilitation with Zirconia. Conclusion: Surgery of residual alveolar ridge augmentation with connective tissue graft gives the patient favorable aesthetic results in the anterior area when it will be rehabilitated.

A New Fully Differential Adaptive CMOS Line Driver Using Fuzzy Controller Suitable for ADSL Modems

In this paper, a new principle for an adaptive line driver using Fuzzy logic is presented. This type of line driver can adapt its output impedance and gain, automatically to the applied load using a fuzzy logic controller (FLC). This results in automatically corrected output impedance for different cables with terminations. Also, the line driver output impedance and gain become insensitive to process and line variations. As an example, a line driver for ADSL application has been designed. The circuit operates from a 3.3 v in a 0.35 um standard CMOS technology. The power consumption of FLC is about 1 mW. The circuit dissipates 106 mW and exhibits a -62 dB THD for a 3.2-Vpp signal at 5 MHz across a 75 ohms Load. It has a relatively high -3 dB bandwidth (240 MHz) with good phase margin of about 67 degrees in a 10 pF load capacitor.

甲B类液体全压力储罐消防设计问题研究

对沸点低于45℃的甲B类液体全压力储罐消防设计、审查过程中存在的问题进行了较为全面的分析,并针对这些问题提出了解决的方法,为进一步完善相关工程设计规范和有效地执行这些规范提供了实例,以期给同类工程提供有益借鉴。

Coupled single-cell and bulk RNA-seq analysis reveals the engulfment role of endothelial cells in atherosclerosis

The clearance of apoptotic cell debris,containing professional phagocytosis and non-professional phagocytosis,is essential for maintaining the homeostasis of healthy tissues.Here,we discovered that endothelial cells could engulf apoptotic cell debris in atherosclerotic plaque.Single-cell RNA sequencing(RNA-seq)has revealed a unique endothelial cell subpopulation in atherosclerosis,which was strongly associated with vascular injury-related pathways.Moreover,integrated analysis of three vascular injury-related RNA-seq datasets showed that the expression of scavenger receptor class B type 1(SR-B1)was up-regulated and specifically enriched in the phagocytosis pathway under vascular injury circumstances.Single-cell RNA-seq and bulk RNA-seq indicate that SR-B1 was highly expressed in a unique endothelial cell subpopulation of mouse aorta and strongly associated with the reorganization of cellular adherent junctions and cytoskeleton which were necessary for phagocytosis.Furthermore,SR-B1 was strongly required for endothelial cells to engulf apoptotic cell debris in atherosclerotic plaque of both mouse and human aorta.Overall,this study demonstrated that apoptotic cell debris could be engulfed by endothelial cells through SR-B1 and associated with the reorganization of cellular adherent junctions and cytoskeleton.

充装压力对全氟己酮抑制油类火焰的影响

设计和搭建了全氟己酮灭火剂抑制B类火焰效应实验系统和过火尾气采集装置,以此研究了灭火瓶充装压力对灭火过程中瓶内压力、喷嘴处压力、灭火剂输出流量、灭火时间和过火尾气组成的影响,采用离子色谱法测试尾气中HF含量,用气质联用法分析尾气的其它气体组分。结果表明,充装压力从1.5 MPa增加至4.2 MPa时,灭火剂喷射流量逐渐增大。充装压力在1.5~2.5 MPa时,喷射流量增幅约为30%,在2.5~4.2 MPa,喷射流量增幅约5%;随着充装压力的增加,过火尾气中氟化氢含量逐渐减少,降幅约40%。过火尾气中还含有六氟丙烯、七氟丙烷、全氟丙烷及全氟庚烷等含氟气体。

Expression pattern and tissue localization of the class B scavenger receptor BmSCRBQ4 in Bombyx moil

Class B scavenger receptors （SR-Bs） are cell surface glycoproteins involved in various physiological processes in vivo, including the transport and metabolism of lipids, binding and phagoeytosis of xenobiotics, and signaling. But little information is available about silkworm SR-Bs; it is necessary to study these SR-Bs for revealing their function. In this study, we cloned the full-length coding sequence of BrnSCRBQ4, a SR-B gene from the silkworm Bombyx mori L. We found that the BmSCRBQ4 gene consists of nine exons and eight introns, with an open reading frame of 1371 bp encoding 456 amino acids. Gene expression studies determined that BmSCRBQ4 messenger RNA （mRNA） was expressed in unfertilized eggs, during embryonic development and throughout the majority of the larval period. Expression of mRNA was detected in the mid gut, middle silk gland, posterior silk gland, head, integumentum, fat body, testes and the ovaries of the larval B. mori Dazao strain, as well as in the silkworm cell lines BmN and BmE. Protein expression studies found BmSCRBQ4 protein was expressed only in the testes, fat body and middle silk gland of larvae, as well as in the silkworm cell lines BmN and BmE. The BmSCRBQ4 protein showed variability in banding patterns in different tissues and cells when analyzed by Western blotting. Immunohistochemical staining showed that the BmSCRBQ4 protein localizes to the constitutive membranes or cellular membranes of these tissues. These results indicated that BmSCRBQ4 gene may play some physiologically relevant roles at the cell surface in each tissue.

Role of sphingosine 1-phosphate in anti-atherogenic actions of high-density lipoprotein

The reverse cholesterol transport mediated by high-density lipoprotein (HDL) is an important mechanism for maintaining body cholesterol, and hence, the crucial anti-atherogenic action of the lipoprotein. Recent studies, however, have shown that HDL exerts a variety of anti-inflammatory and anti-atherogenic actions independently of cholesterol metabolism. The present review provides an overview of the roles of sphingosine 1-phosphate (S1P)/S1P receptor and apolipoprotein A-I/scavenger receptor class B type I systems in the anti-atherogenic HDL actions. In addition, the physiological significance of the existence of S1P in the HDL particles is discussed.