Socio-Demographic and Occupational Aspects of HIV-HBV Co-Infection in Bangui, Central African Republic (CAR): Hospital-Based Cross-Sectional Study

Objective: HIV-HBV co-infection is a major public health problem that has not been sufficiently explored in the Central African workplace. The aim of this study was to assess the frequency of HIV-HBV co-infection among people who living with HIV (PLHIV) in the infectious and tropical diseases department of the Centre Hospitalier Universitaire de lAmiti Sino-Centrafricaine in Bangui. Methods: A retrospective study was carried out from January 1, 2010 to December 31, 2021 in the Infectious and Tropical Diseases Department at the Amiti Sino-Centrafricaine University Hospital. It included the files of all PLHIV, which included the results of HBV serology. A standardized form was used to collect socio-demographic and professional data by documentary review. Data was analysed using Epi-Info 7 software. Means, proportions were calculated as well as Chi square witch was significant if p-value was below 0.05. Results: The study included 265 patients, 188 were women (70.1%) and 77 men (29.1%), giving a sex ratio of 0.45. Mean age was 35.8 years, higher in men (40 years) than in women (35.8 years) (p 0.0001). The age groups 25 to 34 (37.7%) and 35 to 44 (33.6%) were in the majority (71.3%). The majority of PLHIV were unemployed (57.1%), including housewives (43.0%). HBV prevalence was 14.3%, including 7.2% among the unemployed, who account for half of all co-infections. The search for associations between HIV-HBV co-infection and all socio-demographic characteristics (age, sex, marital status) and socio-professional categories showed no significant difference (p 0.05). Conclusion: PLHIV were predominantly young adults, female, and unemployed;no occupation was significantly associated with co-infection. The vast majority of co-infected people were not covered by the occupational health system (unemployed or informal sector). Urgent action is needed to improve workers access to occupational medicine in CAR.

Inhibition of fibroblast activation protein ameliorates cartilage matrix degradation and osteoarthritis progression

Fibroblast activation protein(Fap)is a serine protease that degrades denatured type I collagen,α2-antiplasmin and FGF21.Fap is highly expressed in bone marrow stromal cells and functions as an osteogenic suppressor and can be inhibited by the bone growth factor Osteolectin(Oln).Fap is also expressed in synovial fibroblasts and positively correlated with the severity of rheumatoid arthritis(RA).However,whether Fap plays a critical role in osteoarthritis(OA)remains poorly understood.Here,we found that Fap is significantly elevated in osteoarthritic synovium,while the genetic deletion or pharmacological inhibition of Fap significantly ameliorated posttraumatic OA in mice.Mechanistically,we found that Fap degrades denatured type II collagen(Col II)and Mmp13-cleaved native Col II.Intra-articular injection of r Fap significantly accelerated Col II degradation and OA progression.In contrast,Oln is expressed in the superficial layer of articular cartilage and is significantly downregulated in OA.Genetic deletion of Oln significantly exacerbated OA progression,which was partially rescued by Fap deletion or inhibition.Intra-articular injection of r Oln significantly ameliorated OA progression.Taken together,these findings identify Fap as a critical pathogenic factor in OA that could be targeted by both synthetic and endogenous inhibitors to ameliorate articular cartilage degradation.

Mortality of Children in the Intensive Care Unit of the Pediatric University Hospital of Bangui

Background: In sub-Saharan Africa, one in 13 children died before their fifth birthday. Objective: To study mortality among children hospitalized in the intensive care unit of the CHUPB. Methodology: This was a retrospective, descriptive study over a 12-month period. Included were children aged 1 month to 15 years hospitalized in the intensive care unit and who died during the period. The data were entered and analyzed through the Epi Info software. The statistical test used was Pearson’s chi2. Results: The overall mortality rate was 21.49%. The sex ratio was 1.14 and the mean age was 3.17 ± 2.21 years. Children 5 years of age accounted for 78.49% (n = 197) of cases. Deaths were more frequent in January, April and December. The mean time to consultation was 6.91 ± 1.8 days. Fever 78.48% (n = 197), diarrhea/vomiting 35.45% (n = 89) and convulsions 26.29% (n = 66) were the main reasons for consultation. Prior to admission, treatment was administered in 73.38% (n = 184) of children. The main diagnoses of death were: septic shock 29.08% (n = 73), hypovolemic shock post AEG 17.13% (n = 43), severe malaria 10.76% (n = 27) and meningitis 6.38% (n = 16). Death was early in 66.53% (n = 167) of cases. It was influenced by male sex, origin of residence, rural residence, herbal medicine and the occurrence of deaths during the shifts after 16 hours. Conclusion: Mortality in pediatrics remains a concern in our practice. It is related to conditions that are mostly preventable by vaccination, information, education and communication.

Abundance and Source Identification of Polycyclic Aromatic Hydrocarbons in Sediments of the Ivory Coastal Zone (Toukouzou Hozalem-Assinie)

Polycyclic aromatic hydrocarbons (PAHs) are strongly associated with agricultural, residential, transportation, industrial and petroleum activities. In this study, the presence of PAHs (polycyclic aromatic hydrocarbons) was investigated in sediments of the ivory coastal zone (Toukouzou Hozalem-Assinie). The main objectives of this study were to determine the abundance and to predict the source of PAHs in the sediments. Gas chromatography-mass spectrometry (GC-MS) was used to analyze sixteen priority PAHs. Total PAHs concentrations were from 1.31 to 3992.68 mg/kg in sediment with an average concentration of (307.54 ± 16.10) mg/kg. Among all PAHs, Naphthalene (Nap = 332.72 mg/kg) and Phenanthrene (Phe = 41.75 mg/kg) were found in the highest concentration, whereas Benzo (k) Fluoranthene was found in the least concentration in the range of 0 - 0.85 mg/kg (mean 0.24 mg/kg). Bassam-Modeste Lagune (BML) sampling site was the site with the highest concentration of total PAHs (all 16 PAHs) compared to the others due to their location in a highly populated estuary area that receives commercial, tourism, port, petroleum and heavy industrial activities. Diagnostic ratios were used to determine the sources of PAHs and suggested that the PAH profile in the sediments was dominated by 2 and 3 ring PAHs. The patterns of PAH compounds in sediment indicated that contamination is from mixed sources, with a strong indication of petrogenic contamination potentially from spills of fuel, oil and industrial activities.

Microstructure of Carbon Fiber and Carbon Reinforced Plastic

This study is the investigation of the microstructure of different types of carbon fiber. They were compared with the carbonized and graphitized fibers. Results of structural researches have been presented. It was found that the damage varies from different pollution and the damage of the monofibers. The effect of the pollution of the monofiber was determined.

Dynamics of Interstitial Calcium in Rat Myocardial Ischemia Reperfusion Injury In Vivo

Intracellular calcium overload is a key factor for myocardial ischemia reperfusion injury（IR）. However, there was no report for interstitial calcium concentration dynamics. We investigated the interstitial calcium dynamics in rat myocardial IR model in vivo. A microdialysis system was involved, and the time delay of the system and recovery time was introduced and tested with a fluids switching method. Twelve SD rats were divided into IR or control group. Myocardial IR was induced by ligating（20 min） then releasing（60 min） the suture underlying left anterior descending branch. Mycrodialyisis probe was implanted into the left ventricular myocardium perfusion area for occlusion. Dialysate samples were collected every 10 min. Dialysate calcium concentration was detected with an atomic absorption spectrophotometer. Recovery time for the microdialysis system was 20 min, and recovery rate was 16%. Dialysate calcium concentration showed no changes during ischemia, descended immediately after reperfusion, reached the lowest level（67% of baseline value） 20 min after reperfusion, then escalated slowly. Recovery time was an important parameter for mycrodialysis technique, and it should not be neglected and needed to be tested. Our data suggest that interstitial calcium concentration in rats with myocardial IR in vivo kept steady in ischemia, descended rapidly at the initial reperfusion, then rebounded slowly. In conclusion, we introduced the concept of recovery time for microdialysis and provided a simple testing method.

Molecular mechanism of carvedilol in attenuating the reversion to fetal energy metabolism during cardiac hypertrophy development

Objective: To explore the molecular regulation mechanism of carvedilol in attenuating the reversion back towards fetal energy metabolism during the development of cardiac hypertrophy induced by coarctation of abdominal aorta (CAA) in male Wistar rats. Methods: Hemodynamic and ventricular remodeling parameters, free fatty acid content in the serum were measured in the experimental animals at 16 weeks after the surgical CAA, the rats receiving carvedilol intervention (CAR) after CAA, and those with sham operation (SH). The expressions of muscle carnitine palmitoyltransferaseⅠ (M-CPTⅠ) and medium chain acyl-CoA dehydrogenase (MCAD) mRNA in the cardiac myocytes from every group were studied with RT-PCR. Results: Significant left ventricular hypertrophy were observed in the rats 16 weeks after coarctation operation (P<0.05), together with significant free fatty acids accumulation and downregulation of M-CPTⅠ and MCAD mRNA (P<0.05) in CAA group. Carvedilol at a dose of 30 mg/kg/d for 12 weeks inhibited the left ventricular hypertrophy induced by pressure overload and enhanced the gene expressions of rate-limiting enzyme (M-CPTⅠ) and key enzyme of fatty acid (MCAD) in the CAR group compared with CAA group (P<0.05). Conclusion: Pressure overload-induced hypertrophy in CAA rats causes the reversion back towards fetal enery metabolism, that is, downregulates the expressions of rate-limiting enzyme and key enzyme of fatty acid oxidation. The intervention therapy with carvedilol, a vasodilating alpha- and beta-adrenoreceptor antagonist, attenuates the reversion of the metabolic gene expression to fetal type through upregulating M-CPTⅠ and MCAD mRNA expressions. Thus, carvedilol may exert cardioprotective effects on heart failure by the mechanism of preserving the adult metabolic gene regulation.

Development of Experimental Device for Compression Load Deflection of Car Door Seals

A new experimental device has been developed for analyzing compression load deflection of the door seal by using stereovision theory. Precision instruments of optical grating and force sensor are also integrated in this device. Force-displacement response characteristics of compression at varied speed can be controlled. Solid foundations for characteristic and structure as well as optimization design of the car door seal are elucidated.

Analysis of Daily Rainfall in São Carlos/SP, Brazil over 1979-2017 Using Laplace Trend Test

Rainfall expresses one of the most complex climate factors in Southeastern Brazil. Understanding the dynamics and temporal trends of rainfall represents a significant challenge due to regional and even global mechanisms, such as FS (Frontal Systems) and the SACZ (South Atlantic Convergence Zone), and the interaction with the Atlantic and Pacific Oceans. The present study aimed at analyzing the pluviometric tendencies in São Carlos/SP, in the countryside of São Paulo State. Laplace trend test was used to comprehend the temporal evolution of daily rainfall in the region in the historical series 1979-2017, in seven pluviometric stations (climatological or surface stations). Significant fluctuations in interannual trends and between seasons were observed. However, it was noted that the beginning of the 1980s showed positive trends, whereas, as of the year 2000, most of the stations demonstrated negative trends, indicating a reduction in daily rainfall volume due to the great tropical climatic variability of Brazil. Emphasis should also be given to the regional and local effects, such as elevation and urbanization, respectively, which corroborate such differences among the analyzed stations. This methodology is of considerable value for the observation of pluviometric trends, and future studies can validate such a tool in climatological studies.

两轴径向独立轮副轨道车辆动力学性能

针对独立车轮导向问题提出后倾角导向方法,使独立轮副轨道车辆获得自导向能力。阐述车辆的自导向原理,利用横向轮轨力和后倾角力臂形成摇头力矩,使独立车轮自动转向。关于中心对称的前后独立轮副分别向相反方向转向,使独立车轮处于径向位置。采用多体动力学方法分析独立轮副轨道车辆的自导向性能。结果表明:在直线轨道上,后倾角对车辆横向位移和摇头角的影响明显。带后倾角车辆出现类蛇行运动现象。具有后倾角的车辆在直线轨道上能够自动复位。在曲线轨道上,左前导向轮具有较大的冲角。后倾角能够使车辆动态对中,最终回到轨道中心线位置。带后倾角的独立轮副轨道车辆在曲线轨道上具有有限的导向能力。

基于桥梁响应的高速铁路简支梁离心力折减方法

为分析规范离心力计算公式中竖向活载折减系数的理论来源,建立列车-曲线桥-墩系统的空间模型进行车桥耦合振动仿真计算。提出以桥梁动力响应与设计离心力产生的静力响应之比作为竖向活载折减系数的方法,结合反向传播神经网络分析列车车速、桥梁墩高、跨度、曲线半径等因素对折减系数的影响程度。结果表明:车速对折减系数的影响最大,其次为桥梁跨度;竖向活载折减系数反映了列车荷载图式中设计活载与运营列车轴重的差异,折减系数应与列车荷载图式、实际运营列车相匹配;现行规范中竖向活载折减系数公式对中国高速铁路ZK荷载具有良好的适配性,能满足高速铁路简支梁离心力设计的要求。

遗传算法在橡胶超弹性材料参数反求中的应用

将优化算法与有限元仿真分析相结合可以对橡胶的材料参数进行反求,该方法基于一款叠层橡胶弹簧的试验数据,并选用Mooney-Rivlin超弹性本构模型。在参数反求的过程中,为解决传统遗传算法出现的早熟、稳定性差以及收敛速度慢的问题,将编码方式改为实数编码,并在算法中引入精英保留策略和自适应的交叉与变异概率。将根据改进遗传算法反求得到的刚度特性曲线与试验结果进行对比,发现二者具有很好的一致性,表明通过反求得到的材料参数能准确地对橡胶材料的力学性能进行描述。

Therapeutic silencing miR-146b-5p improves cardiac remodeling in a porcine model of myocardial infarction by modulating the wound reparative phenotype

Fibrotic remodeling is an adverse consequence of immune response-driven phenotypic modulation of cardiac cells following myocardial infarction(Ml).MicroRNA-146b(miR-146b)is an active regulator of immunomodulation,but its function in the cardiac inflammatory cascade and its clinical implication in fibrotic remodeling following Ml remain largely unknown.Herein,miR-146b-5p was found to be upregulated in the infarcted myocardium of mice and the serum of myocardial ischemia patients.Gain-and loss-of-function experiments demonstrated that miR-146b-5p was a hypoxia-induced regulator that governed the pro-fibrotic phenotype transition of cardiac cells.Overexpression of miR-146b-5p activated fibroblast proliferation,migration,and fibroblast-to-myofibroblast transition,impaired endothelial cell function and stress survival,and disturbed macrophage paracrine signaling.Interestingly,the opposite effects were observed when miR-146b-5p expression was inhibited.Luciferase assays and rescue studies demonstrated that the miR-146b-5p target genes mediating the above phenotypic modulations included interleukin 1 receptor associated kinase 1(IRAKI)and carcinoembryonic antigen related cell adhesion molecule 1(CEACAM1).Local delivery of a miR-146b-5p antagomir significantly reduced fibrosis and cell death,and upregulated capillary and reparative macrophages in the infarcted myocardium to restore cardiac remodeling and function in both mouse and porcine Ml models.Local inhibition of miR-146b-5p may represent a novel therapeutic approach to treat cardiac fibrotic remodeling and dysfunction following Ml.

Research Progress of Non-oxide and High Entropy Ceramic Coatings

Ceramic coatings play a keyrole in extending the service life of materials in aerospaceandenergy fields byprotectingmaterials from high temperature,oxidation,corrosion and thermal stress.Non-oxide and high entropy ceramics are new emerging coating materials which have been researched and developed in recent years.Compared with traditional oxide ceramics,non-oxide ceramics have better high temperature stability,oxidation resistance and erosion resistance.These characteristics make non-oxide ceramics perform well in extreme environments.It is particularly noteworthy that the non-oxide high entropy ceramic is a uniform solid solution composed of at least four or fiveatoms.Their unique structure and outstanding propertiesshow great potential application in the field of coating.In this paper,the researches aboutregulating microstructure,preparation technology and properties of nitride and its high entropy system,carbide and its high entropy system and boride and its high entropy system in coating field are summarized,and their future development and prospects are prospected.

基于风险的不良地质铁路山岭隧道施工安全管理研究

岩堆、软岩大变形、岩溶及富水断层、煤层、高地应力等不良地质对隧道施工安全影响大,对施工人员安全会造成极大威胁并大幅增加工程成本。开展基于风险的不良地质铁路山岭隧道施工安全管理研究,对于确保隧道施工安全意义重大。文章通过梳理铁路山岭隧道施工不良地质风险控制要点,结合郑渝高铁向家湾隧道施工安全管理实践,以具体突水事件处置过程为案例,总结利用超前预报和围岩监控量测、有害气体监测等手段,并以平导超前施工实现超前地质预报,充分发挥风险管理平台作用,制定针对性工程措施等安全管理成果。研究提出建立安全管理体系、强化安全过程控制、提高安全风险管理信息化应用水平、提高重大风险防范化解和应急处置能力等建议。

季冻区无砟轨道损伤变形及其对车轨动力响应的影响研究

为探究季冻区无砟轨道损伤变形对行车安全性和轨道服役性能的影响规律,以我国季冻区典型无砟轨道结构为研究对象,基于有限元方法和混凝土塑性损伤本构理论,建立考虑结构配筋的CRTS III型板式无砟轨道精细化非线性分析模型,研究路基冻胀作用下轨道结构的变形和损伤规律;结合多体动力学方法,建立高速车辆-轨道-路基耦合系统动力学模型,分析路基冻胀变形作用下高速铁路车-线-路基耦合系统动力响应。结果表明:冻胀位置对轨道结构伤损变形和离缝的产生和发展影响显著;当冻胀发生在底座板凹槽中间位置时,离缝值最大,当冻胀发生在底座板凹槽位置时,钢轨位移最大;当冻胀发生在底座板伸缩缝位置时,底座板最早产生宏观裂纹;轨道结构的变形损伤和层间离缝随着冻胀幅值增加、冻胀波长减小而增加;底座板相较于其他轨道结构更容易产生损伤,建议将底座板底面波脚产生裂纹的冻胀量作为控制标准;路基不均匀冻胀会加剧轮轨动态相互作用,进而对行车安全性和轨道服役性能产生不良影响;高速铁路的轮轨垂向动力响应随着路基冻胀幅值的增加而增大;20 m冻胀波长以下的冻胀变形及其幅值增大对车轨动力响应影响尤为严重,应予以重视。研究结论以期为季冻区高速铁路路基段基础结构动态性能演变及服役安全提供理论基础和工程指导。

大跨度铁路桥梁整体变形波长特征分析

针对三座大跨度桥(A桥和C桥为悬索桥、B桥为斜拉桥)分别建立有限元模型,分析在温度、沉降、风、列车等作用下的桥面整体变形波长特征,并采用HHT(Hilbert‐Huang Transform)法、中点弦测法和曲率半径法定量分析桥面变形波长。结果表明:A桥在整体升降温作用下,产生的变形曲线为波长82~140 m、波幅不超过5.5 mm的曲线段;在静风荷载作用下,产生的变形曲线为波长97~140 m、波幅不超过5.4 mm的曲线段;桥塔沉降作用下A桥不产生显著变形曲线。上述三种荷载作用下B桥均不产生显著变形曲线。C桥在整体升降温作用下,产生的变形曲线为波长70~84 m、波幅不超过2.2 mm的曲线段;桥塔沉降和静风力作用下C桥均不产生显著变形曲线。列车全局荷载对三座桥的桥面变形产生影响,若关注幅值3 mm及以上的曲线段,A桥、B桥、C桥最短波长依次为66、93、53 m。就此三座桥梁而言,荷载引起的桥面垂向变形对行车性能影响的显著程度均依次为列车全局荷载、整体升温、桥塔沉降。

车辆服役环境对高速列车轴箱轴承温度的影响分析

构建考虑轴箱表面散热及轴承内部传热的功率损耗模型,分析轴箱轴承在不同服役环境下的载荷;综合考虑轴箱表面空气流场对流换热的影响,建立精细化轴箱轴承温度模型,分析不同服役环境对轴箱轴承温度分布和温度特性的影响,并通过轴承试验台验证模型的有效性。研究结果表明:当车辆速度由220 km/h增至300 km/h时,轴承的总摩擦力矩增大11.4%;当车轮多边形阶数由16阶增加到22阶时,摩擦力矩平均增大2.8%;轴箱轴承最高温度出现在内圈与滚动体接触的区域,最低温度出现在轴上且接近环境温度;当车速由220 km/h增加到300 km/h时,轴承的最高温度上升9.2℃,各节点处温度均有一定程度增加,当车轮多边形阶数由16阶增加到22阶时,最高温度平均升高1.1%;当多边形深度幅值由10 dB增加到18 dB时,最高温度平均升高1.4%。

既有铁路客车服役性能研究

我国既有铁路客车保有量大、运用时空环境复杂,其服役性能的演变对运行安全和运维保障带来极大挑战。为系统掌握铁路客车服役状态,调研我国普速客车运营现状,并以车体钢结构为例,开展影响客车服役性能的因素分析。调研发现,大部分普速客车已逐步进入服役中后期,5T等信息化手段实现了对客车的全面监控。不同运用环境下,钢结构腐蚀情况不同,随着运行时间/运行里程的增加,钢结构腐蚀有明显加剧趋势。针对服役期间RW25G车体和209P型转向架疲劳强度开展研究,各关键部位均满足服役寿命30年设计要求;针对服役期间YZ25T车体和CW-200K型转向架开展跟踪测试,发现转向架个别关键承载位置产生损伤值较大。针对服役期间25T型客车动力学性能开展研究,采用TPDS、TCDS和添乘等手段开展跟踪测试,并结合实测车轮磨耗数据和减振器劣化数据开展仿真分析,结果表明,在1个旋修周期内,车辆运行安全性存在一定冗余;随服役时间增加,转向架关键部件的性能劣化或失效会对车辆蛇行稳定性和运行平稳性产生不利影响;开展随机参数的动力学仿真,发现极端工况下轮重减载率上升明显,应予以充分关注。

建模方式对调车冲击仿真的影响研究

为了研究不同建模方式的仿真模型对调车冲击计算效率和结果的影响,根据C80敞车及MT-2缓冲器参数,建立模拟调车冲击工况的纵向动力学模型A、三维精细化模型B和混合动力学模型C,分析了在不同速度、空重车状态及不同编组方式下的调车冲击的响应结果,并在此基础上讨论了模型的建模方便性、计算效率等问题.研究结果表明:(1)随着冲击速度的增加,三种模型得到的最大车钩力变化趋势一致,但是结果差异越来越大,在8km/h时仿真差异可达15%,同时空车状态下分析的结果最大差异为8.9%,大于重车状态仿真的2.4%;(2)不同编组方式得到的车钩力时间历程规律类似,在不同车钩位置上比较时最大差异为8%左右;(3)建模方便性上各有难点,但模型A的数据库在界面调用更为方便,且在计算时间上远远小于其他两种模型.