Logistic regression analysis on risk factors for vascular dementia following cerebral infarction in 403 patients from Chongqing City Hospital and family follow-up studies

BACKGROUND： Studies have demonstrated that the risk factors of vascular dementia following stroke are greatly different in region, race and other aspects. OBJECTIVE： To analyze the conditions and incidental risk factors of vascular dementia in patients with acute cerebral infarction from Chongqing City. DESIGN： Case analysis. SETTING： Department of Neurology, Daping Hospital, Third Military Medical University of Chinese PLA. PARTICIPANTS： Altogether 546 inpatients with acute ischemic stroke admitted to Department of Neurology, Daping Hospital, Third Military Medical University of Chinese PLA between May 1999 and December 2002 were involved in this study. The involved patients, including 295 males and 251 females, aged 55 - 94 years, dwelled in Chongqing over 5 years. They were admitted to hospital within 48 hours of attack of acute ischemic stroke, and survived for over 3 months. Informed consents were obtained from all the involved subjects. METHODS： ① Following the same standard, cognitive and social function evaluations were conducted by one physician on admission and 3 months after admission, Unified questionnaire, consisting of general characteristics, vascular risk factors, stroke characteristics, neurological physical sign, and other 28 factors of involved subjects, was used in all the patients. According to the investigation results, the patients were assigned into 2 groups： dementia group and non-dementia group. ②Ischemic stroke was diagnosed according to acute ischemic brain disorder 〉 24 hours and CT or MRI imageology.③ Neurophysiological examination was conducted in all the patients at 7 to l0 days after stroke （score was two SD less than or equaled to normal level was considered as abnormal）. ④Diagnosis and statistics of dementia were carried out with Mini-Mental State Examination and The Diagnostic and Statistical Manual of Mental Disorders-Ⅳ （published by American Psychiatric Association） on admission and 3 months after admission. Neurologic deficit scoring was carried out with the National Institutes of Health Stroke Scale. ⑤ Chi-square test was used for categorical variable, and t test for quantitative variable between dementia group and non-dementia group. Dementia-related factors were performed multiple-factor Logistic regression model analysis. MAIN OUTCOME MEASURES： Incidence of dementia and dementia-related risk factors of patients. RESULTS： Altogether 546 patients with stroke were involved in this study, 403 of them participated in the final analysis, and 143 dropped out. A total of 342 were followed-up in the hospital and 61 at home. At 3 months after cerebral infarction, vascular dementia occurred in 87 （21.6%） of 403 patients. The main risk factors were age （OR 1.179; 95%CI 1.130 - 1.230）, low education level （OR 1.806; 95%CI 1.024 - 3.186）, daily alcohol drinking （OR 3.447; 95%（1/ 1.591 - 7.468）, stroke history （OR 2.531; 95%CI 1.419 - 4.512）, atrial fibrilation（OR 3.475; 95%CI 1.712 - 7.057）, dysphonia （OR 5.873; 95%6/2.620 - 13.163） and left carotid artery infarction （OR 1.975; 95%（1/1.152 - 3.388）. CONCLUSION： The incidence of vascular dementia is determined by synthetic action of multiple risk factors. Dysphonia is the most important influencing factor.

Nutritional Support under the Neuman Systems Model for Stroke Patients

Objective: To explore nutritional support under the Neuman systems model in treating dysphagia in stroke patients. Methods: In this retrospective study, we enrolled 97 patients with dysphagia after stroke admitted to our hospital, and randomly divided them into the Neuman group (n = 51) given nursing intervention based on Neuman systems model and a control group (n = 46) given routine nursing intervention. Both groups received nutritional support for 3 months. Nutritional indexes (serum total protein, plasma albumin, serum albumin, hemoglobin and transferrin levels) and immune indexes (immunoglobulin (Ig) A, IgG, IgM and total lymphocyte count (TLC) in both groups were recorded and compared. Pulmonary function recovery, video fluoroscopic swallowing study score, water swallowing test score, complication rate, and health knowledge mastery level were also compared between the two groups. Results: After the intervention, the Neuman group showed less decrease in the nutritional and immune index scores (serum total protein, plasma albumin, hemoglobin, serum albumin;IgA, IgG, IgM, and TLC;all P Conclusion: For patients with stroke and dysphagia, comprehensive nursing intervention (e.g., nutritional support) under theNeuman systems model can promote the recovery of immune, swallowing, and pulmonary function, reduce complication incidence and facilitate comprehensive rehabilitation, ensuring adequate nutritional intake.

草鱼疫苗连续自动注射装置设计与试验

草鱼疫苗注射主要依靠人工注射,具有劳动强度大、注射效率低、注射位置非标准化和注射精准度差等缺点,严重制约水产养殖的发展。根据草鱼疫苗注射特点,制定了疫苗自动注射作业策略,通过开展鱼苗姿态自动识别与快速调整、注射工位自动分配、鱼体输送与拨杆LS-DYNA动力学仿真分析、鱼体柔性固定与快速注射等技术研究,研制了疫苗自动注射样机,以100~120 mm长的草鱼鱼苗为自动注射对象进行试验。结果显示:草鱼疫苗自动注射装置产量约为900尾/h,试验鱼苗注射疫苗后3周内的存活率达到98.3%,存活率较人工疫苗注射提高4个百分点。该装置实现了草鱼幼苗的高效连续注射,提高了水产养殖装备自动化水平,对纺锤形鱼幼苗的连续注射均具有参考意义,具有较高应用价值与经济效益。

相切四圆弧谐波柔轮车齿加工及其刀具设计方法

相切四圆弧谐波齿轮具有承载力强和传动平稳的显著优势。为满足相切四圆弧谐波齿轮的高效率、高精度加工要求,提出基于双自由度线面共轭理论的相切四圆弧谐波柔轮车齿加工及其刀具设计方法。通过建立车齿加工展成运动模型和相切四圆弧谐波柔轮多圆弧齿廓数学模型,推导出产形轮刀刃线与被创成齿面的双自由度线面共轭车齿啮合条件;并求解刀具共轭曲面和法面方程,得到无理论误差的车齿刀具法面刃形;最后,设计制造出基于端面切削刃的车齿刀具。通过仿真加工和切削实验,验证说明相切四圆弧谐波柔轮车齿加工及其刀具设计方法具有较高的加工精度。结果可为相切四圆弧谐波齿轮的高效、高精加工提供指导。

辽宁省大学生语言文字应用能力调查研究

本研究对辽宁省大学生语言文字应用的普遍水平与现实情况进行测试及调查,得出当前大学生语言文字应用能力的现存问题及主要原因。结果表明,提高大学生语言文字应用能力仍需高校在强化语言文字教育、主动融入推普社会实践、探索新型数字赋能举措等方面做出努力。

智能可穿戴设备BPMpathway在全膝关节置换术后患者居家康复中的应用效果

目的·评价基于智能可穿戴设备BPMpathway的居家康复方案在全膝关节置换(total knee arthroplasty,TKA)术后患者中的应用效果。方法·采用方便抽样法,选取苏州大学附属第四医院(苏州市独墅湖医院)和苏州大学附属第一医院骨科2021年4月—2022年12月收治的膝关节骨关节炎并接受TKA术的患者作为研究对象。按照患者入院顺序,将住院号尾数为奇数的患者纳入对照组,住院号尾数为偶数的患者纳入干预组。对照组患者给予常规居家康复训练方案,干预组在对照组的基础上实施基于BPMpathway的远程居家康复训练方案。分别于基线及术后1、3、6个月采用骨科患者功能锻炼依从性量表、美国特种外科医院膝关节评分表(Hospital for Special Surgery Scale,HSS)和36项简明健康状况调查表(36-item Short Form Health Survey,SF-36)对2组患者进行测评,同时测量患者的膝关节活动度。结果·最终纳入110例患者,其中对照组56例,干预组54例。2组患者的一般资料差异无统计学意义。2组患者基线时的膝关节活动度、HSS评分、SF-36评分差异均无统计学意义。重复测量方差分析结果显示:2组患者膝关节活动度、功能锻炼依从性评分、HSS评分及SF-36评分的组间效应、时间效应及交互效应均具有统计学意义(均P<0.05)。术后1、3、6个月干预组的膝关节活动度、功能锻炼依从性评分、HSS评分及SF-36评分均高于对照组(均P<0.05)。结论·医护人员基于智能可穿戴设备BPMpathway开展的远程康复训练方案,有助于提高TKA术后患者居家康复期间功能锻炼的依从性,改善膝关节活动度,促使膝关节功能恢复,提高其生存质量,对患者预后具有积极的作用。

基于白光中子源的^(197)Au中子辐射俘获截面测量及共振参数分析

中子辐射俘获反应在反应堆运行、核装置设计及核天体物理研究中起重要的作用.4πBaF_(2)探测装置有着高时间分辨能力、低中子灵敏度、高探测效率等优点,适合开展中子辐射俘获反应截面数据的测量.中国原子能科学研究院核数据重点实验室建立了伽马全吸收装置(Gamma total absorption facility,GTAF),该装置用28块六棱BaF_(2)晶体和12块五棱BaF_(2)晶体构成了外径25 cm,内径10 cm的球壳,覆盖了95.2%的立体角.利用GTAF在中国散裂中子源Back-n束线上,测量了197Au(n,γ)的反应截面数据.测量数据通过能量筛选、PSD方法、晶体多重性筛选进行了初步本底扣除,随后结合对^(nat)C及空样品的测量数据对本底进行了分析及扣除,获得了197Au俘获反应的产额,利用SAMMY程序拟合得到了^(197)Au在1—100 e V的共振能量、中子共振宽度和伽马共振宽度参数.实验测量结果与ENDF/B-VIII.0数据库符合良好,其共振参数存在一定差异,分析原因可能与GTAF能量分辨率、Back-n的中子能谱测量精度、以及实验本底扣除方法相关,这也是下一步工作的重点.

新孢子虫硫氧还蛋白的生物信息学分析及其原核表达的鉴定

为研究新孢子虫硫氧还蛋白(Trx)的生物学特性,本研究利用PCR扩增犬新孢子虫Trx(NcTrx)基因的编码区序列,构建pET-32a(+)-NcTrx原核表达载体,经双酶切与测序鉴定正确后,利用系列生物信息学软件分析NcTrx基因及其编码氨基酸序列的生物信息学特征,并对其蛋白互作网络中排名前100的蛋白进行GO功能和KEGG信号通路的富集分析。重组质粒中NcTrx基因的测序结果显示,NcTrx基因片段为1 287 bp,编码428个氨基酸;该蛋白含1个信号肽,1个跨膜区,主要位于内质网上;NcTrx蛋白的二、三级结构主要由α-螺旋、无规则卷曲组成,有12个B细胞抗原表位;该蛋白属于硫氧还蛋白家族,存在典型的氧化还原基序“-CXXC-”,有38个磷酸化位点、10个O-糖基化位点;与NcTrx蛋白互作最强的为酪氨酸激酶样蛋白,二者通过氢键和静电作用实现相互对接;GO功能及KEGG信号通路的显著性富集分析结果显示,NcTrx与其互作的蛋白主要参与蛋白质转运、蛋白质二硫键异构酶活性等生物学过程,与内质网蛋白质加工、硫代谢等信号通路密切相关。将pET-32a(+)-NcTrx转化BL21(DE3)感受态细胞,并经IPTG诱导表达后采用镍亲和层析法纯化重组NcTrx蛋白(rNcTrx),经SDS-PAGE检测该蛋白的表达及纯化效果,采用Bradford法测定纯化蛋白的浓度。采用western blot鉴定rNcTrx的反应原性。SDS-PAGE结果显示,rNcTrx分子量约66 ku,主要以包涵体的形式表达,且纯化效果较好,浓度为0.8 mg/mL。Western blot检测结果显示,纯化的rNcTrx能够与鼠His MAb、新孢子虫感染的小鼠血清发生特异性反应,在66 ku处出现特异性条带。本研究首次经PCR扩增NcTrx基因,对NcTrx基因及其蛋白进行了生物信息学分析,并经原核系统表达及鉴定了NcTrx蛋白,为后续深入探究该蛋白的生物学功能提供参考依据。

近红外驱动光催化全分解水:进展与展望

实现高效、低成本的太阳能光催化全分解水制氢是解决当前环境污染和化石能源过度使用等问题的理想方案.然而,目前光催化分解水的转化效率(低于10%)普遍较低,这成为其实际应用的主要障碍.从太阳光谱的响应范围来看,现有的光催化剂大多局限于紫外光或可见光区域,而近红外光区的光催化剂开发仍然非常有限.尽管近红外光在太阳光谱中占比超过一半,蕴含着巨大的能源潜力,但遗憾的是,目前大部分光催化剂无法在该波段实现高效的光催化反应.根据理论预测,光分解水的转化效率有望随着催化剂响应太阳光波长范围的扩大而显著提高.因此,如何最大限度地利用太阳能,特别是近红外光区域的光能,开发高效的近红外光响应光催化全解水制氢催化剂,已成为当前能源、环境、化学工程领域研究的热点.本文综述了近红外光驱动全分解水光催化剂在材料设计和调控方面的最新进展,涉及窄带隙半导体、带隙工程、上转换效应、局域表面等离子体效应和光敏化作用等策略.首先,从热力学和动力学的角度分析了近红外光驱动全分解水的难点:对于大多数半导体而言,要实现近红外驱动全分解水不仅要求理论带隙窄于1.77 eV,而且必须超过水氧化还原分解电位(1.23 eV),同时由于存在电位损失和动力学过电位,实际的带隙结构应在1.6–2.4 eV,这对半导体的能带结构提出了较为苛刻的要求.此外,全分解水反应的可逆性、溶解氧的影响以及材料的光稳定性问题也是实现近红外光驱动全分解水的挑战.其次,总结了各方法制备的催化剂全分解水制氢的性能,分析了其近红外光子捕获方法的优缺点,特别指出了如何在每种方法的基础上进一步促进光生载流子的分离以及近红外光子的捕获能力(比如:负载贵金属单原子助催化剂、多种方法结合构筑多元复合体系以及光催化剂表面优化等).同时,强调了在近红外驱动全分解水过程中材料特征、催化性质与功能机理三者之间的关系.尤其是利用等离子体效应和光敏化作用来实现近红外光驱动全分解水的机理,目前尚不明确,需要结合理论计算以及先进的时空分辨仪器进一步研究电荷转移机制.另外,总结了全光谱响应的全分解水制氢光催化剂在材料设计和调控方面的最新进展,包括:光敏化作用的应用、带隙调控的策略、局域表面等离子体效应的研究,以及乌尔巴赫带尾吸收捕获技术的探索.最后,归纳并展望了未来近红外驱动全分解水光催化剂所面临的挑战与机遇.尽管近年来国内外学者们围绕着近红外驱动全分解水制氢光催化剂开展了系列研究工作,取得了一些突破性进展,但近红外驱动全分解水制氢效率仍然较低以及对于近红外响应光催化剂的设计和调控方面仍然面临着许多挑战.如何设计和开发廉价、稳定且高效的近红外驱动全分解水制氢光催化剂仍需进一步探索.因此,未来需要结合不同构筑方法的优势来加强近红外区的光捕获能力、实现多元复合材料界面间的精准调控、通过高端原位时空分辨仪器以及理论计算剖析近红外驱动全分解水的过程等方面对近红外响应光催化材料进行深入研究.

2023年青海省隆宝滩棘球绦虫虫卵污染情况调查

目的了解青海省隆宝滩地区棘球绦虫虫卵的环境污染情况,为有针对性地制定棘球蚴病防治措施提供依据。方法2023年3—4月,在青海省玉树市隆宝镇措桑村的养犬户家庭、村内主要街道及野外区域,分别采集犬科动物粪便、动物毛发、水、土壤、草和食物等不同类型的环境样本,利用PCR技术检测样本棘球绦虫虫卵并比较检出率差异。采用ArcGIS软件并结合ASTER GDEM高程数据,制作样本分布高程地图。结果共采集环境样本400份,棘球绦虫虫卵总检出率为13.50%(54/400);其中犬科动物粪便、动物毛发、水、土壤、草、食物的检出率分别为30.43%(42/138)、5.33%(4/75)、15.38%(2/13)、5.26%(6/114)、0(0/37)、0(0/23)。138份犬科动物粪便中,19份野外粪便未能通过PCR鉴定出动物宿主;其余119份样本中,犬、藏狐、赤狐粪便虫卵检出率分别为11.29%(7/62)、48.84%(21/43)、50.00%(7/14),差异有统计学意义(χ^(2)=20.481,P<0.05)。138份犬科动物粪便中,细粒棘球绦虫、多房棘球绦虫和石渠棘球绦虫虫卵检出率分别为2.17%(3/138)、18.12%(25/138)和16.67%(23/138),差异有统计学意义(χ^(2)=19.858,P<0.05)。75份动物毛发样本中,犬、牛的毛发检出率分别为6.06%(4/66)、0(0/9),差异无统计学意义(P>0.05)。13份水样本中,野外河流溪水、村内井水和村内积水的虫卵检出率分别为20.00%(2/10)、0(0/2)和0(0/1),差异无统计学意义(P>0.05)。114份土壤样本中,养犬户家庭、村内主要街道和野外土壤虫卵检出率分别为15.00%(3/20)、15.00%(3/20)和0(0/74),差异有统计学意义(P<0.05)。动物毛发、水和土壤样本中检出的虫卵均为细粒棘球绦虫。在虫卵分布方面,检出虫卵的犬科动物粪便高度集中于野外道路附近地域,其他环境检出虫卵的样本无明显集中趋势。结论青海隆宝滩地区环境虫卵污染严重且分布广泛,需继续采取犬(特别是未拴养犬)及野外传染源(狐狸)驱虫等防控措施,以减少棘球绦虫虫卵对环境的污染,降低棘球蚴病传播风险。

Clinical manifestations,diagnosis and long-term prognosis of adult autoimmune enteropathy:Experience from Peking Union Medical College Hospital

BACKGROUND Autoimmune enteropathy(AIE)is a rare disease whose diagnosis and long-term prognosis remain challenging,especially for adult AIE patients.AIM To improve overall understanding of this disease’s diagnosis and prognosis.METHODS We retrospectively analyzed the clinical,endoscopic and histopathological characteristics and prognoses of 16 adult AIE patients in our tertiary medical center between 2011 and 2023,whose diagnosis was based on the 2007 diagnostic criteria.RESULTS Diarrhea in AIE patients was characterized by secretory diarrhea.The common endoscopic manifestations were edema,villous blunting and mucosal hyperemia in the duodenum and ileum.Villous blunting(100%),deep crypt lymphocytic infiltration(67%),apoptotic bodies(50%),and mild intraepithelial lymphocytosis(69%)were observed in the duodenal biopsies.Moreover,there were other remarkable abnormalities,including reduced or absent goblet cells(duodenum 94%,ileum 62%),reduced or absent Paneth cells(duodenum 94%,ileum 69%)and neutrophil infiltration(duodenum 100%,ileum 69%).Our patients also fulfilled the 2018 diagnostic criteria but did not match the 2022 diagnostic criteria due to undetectable anti-enterocyte antibodies.All patients received glucocorticoid therapy as the initial medication,of which 14/16 patients achieved a clinical response in 5(IQR:3-20)days.Immunosuppressants were administered to 9 patients with indications of steroid dependence(6/9),steroid refractory status(2/9),or intensified maintenance medication(1/9).During the median of 20.5 months of followup,2 patients died from multiple organ failure,and 1 was diagnosed with non-Hodgkin’s lymphoma.The cumulative relapse-free survival rates were 62.5%,55.6%and 37.0%at 6 months,12 months and 48 months,respectively.CONCLUSION Certain histopathological findings,including a decrease or disappearance of goblet and Paneth cells in intestinal biopsies,might be potential diagnostic criteria for adult AIE.The long-term prognosis is still unsatisfactory despite corticosteroid and immunosuppressant medications,which highlights the need for early diagnosis and novel medications.

BACNN: Multi-scale feature fusion-based bilinear attention convolutional neural network for wood NIR classification

Effective development and utilization of wood resources is critical.Wood modification research has become an integral dimension of wood science research,however,the similarities between modified wood and original wood render it challenging for accurate identification and classification using conventional image classification techniques.So,the development of efficient and accurate wood classification techniques is inevitable.This paper presents a one-dimensional,convolutional neural network(i.e.,BACNN)that combines near-infrared spectroscopy and deep learning techniques to classify poplar,tung,and balsa woods,and PVA,nano-silica-sol and PVA-nano silica sol modified woods of poplar.The results show that BACNN achieves an accuracy of 99.3%on the test set,higher than the 52.9%of the BP neural network and 98.7%of Support Vector Machine compared with traditional machine learning methods and deep learning based methods;it is also higher than the 97.6%of LeNet,98.7%of AlexNet and 99.1%of VGGNet-11.Therefore,the classification method proposed offers potential applications in wood classification,especially with homogeneous modified wood,and it also provides a basis for subsequent wood properties studies.

Microbial phenolic metabolites 3-(3',4'-dihydroxyphenyl)propanoic acid and 3',4'-dihydroxyphenylacetic acid prevent obesity in mice fed high-fat diet

Obesity is associated with numerous metabolic disorders,and dietary polyphenols have been confirmed to have beneficial effects on the metabolism in obesity.However,the effect of 3-(3’,4’-dihydroxyphenyl)propanoic acid(DHPA)and 3’,4’-dihydroxyphenylacetic acid(DHAA),two main metabolites of dietary polyphenols,on obesity remains poorly understood.In this study,DHPA and DHAA were found to alleviate obesity,as well as regulate insulin resistance,lipid metabolism,and oxidative stress response in high-fat diet(HFD)mice.Surprisingly,the 16S rRNA sequencing and UHPLC-Q-TOF/MS demonstrated that DHPA and DHAA only slightly disturbed the intestinal microbiome,but significantly altered the urine metabolome of HFD mice mainly by regulating pentose and glucuronate interconversion,tyrosine metabolism,pentose phosphate and tricarboxylic acid(TCA)cycle as indicated by metabolic pathway analysis based on Kyoto Encyclopedia of Genes and Genomes(KEGG)database.Correlation analysis revealed that the differential metabolites are strongly associated with body weight,blood glucose,insulin level,and superoxide dismutase(SOD)enzyme activity.Our results revealed that DHPA and DHAA exert their anti-obesity effect by regulating important metabolites in the glucose,lipid and tyrosine metabolism pathways.

身心护理模式对手外科显微骨科断指再植术患者自我感受负担及预后的影响

目的探讨身心护理模式对手外科显微骨科断指再植术患者自我感受负担及预后的影响。方法选取本院医院手外科显微骨科2021年1月至12月收治的72例断指再植术的患者为对照组,采用常规护理。选取本院手外科显微骨科2022年1月至12月收治的75例断指再植术的患者为观察组,在常规护理的基础上实施身心护理模式。比较两组患者的自我护理能力、自我感受负担、护理满意度及预后情况。结果与对照组相比,观察组干预后的健康知识水平、自我护理责任感、自我护理技能等自我护理能力方面的评分更高,差异有统计学意义(P<0.05)。观察组干预后的自我感受负担量表(SPBS)评分更低,差异有统计学意义(P<0.05)。两组患者的断肢再植成活率的差异无统计学意义,但与对照组相比,观察组的并发症较少,差异有统计学意义(P<0.05)。观察组在关爱患者、服务态度、业务水平等方面的护理满意度高于对照组,差异有统计学意义(P<0.05)。结论身心护理模式能够提高显微骨科断指再植术患者的自我护理能力,减轻自我感受负担,改善预后,提升护理满意度。

新能源汽车动力电池应用现状及发展探析

传统燃油汽车使用石油作为能源,而石油资源有限且不可再生,相比之下,新能源汽车使用的电力来自可再生能源、核能或燃料电池等,这些能源可持续利用,减少对有限资源的依赖。动力电池是新能源汽车的核心部分,目前多种动力电池被应用于新能源汽车之中,解决了最基本的安全问题、续航问题、充电问题。基于此,文章从新能源汽车动力电池概述出发,对新能源汽车动力电池的优缺点进行分析,进一步阐述了新能源汽车动力电池的应用现状以及发展前景,以期提高动力电池性能,推动新能源汽车行业的发展。

Current progress of research on heat -resistant Mg alloys: A review

With the increasing attention received by lightweight metals,numerous essential fields have increased requirements for mag-nesium(Mg)alloys with good room-temperature and high-temperature mechanical properties.However,the high-temperature mechanic-al properties of commonly used commercial Mg alloys,such as AZ91D,deteriorate considerably with increasing temperatures.Over the past several decades,extensive efforts have been devoted to developing heat-resistant Mg alloys.These approaches either inhibit the gen-eration of thermally unstable phases or promote the formation of thermally stable precipitates/phases in matrices through solid solution or precipitation strengthening.In this review,numerous studies are systematically introduced and discussed.Different alloy systems,includ-ing those based on Mg–Al,Mg–Zn,and Mg–rare earth,are carefully classified and compared to reveal their mechanical properties and strengthening mechanisms.The emphasis,limitations,and future prospects of these heat-resistant Mg alloys are also pointed out and dis-cussed to develop heat-resistant Mg alloys and broaden their potential application areas in the future.

Spontaneous ignition of corrugated cardboard under dynamic high radiant flux

Understanding the response of solid combustibles under high radiant fluxes is critical in predicting the thermal damage from extreme scenarios.Unlike the more moderate radiant fluxes in conventional hydrocarbon fires,extreme events such as strong explosion,concentrated sunlight and directed energy can generate dynamic radiant fluxes at the MW/m^(2) level,creating a unique threat to materials.This study investigates the pyrolysis and spontaneous ignition behaviors of corrugated cardboard by using both experimental and numerical methods,under 10-cm dynamic high radiant fluxes ranging from 0.2 to 1.25 MW/m^(2) for 10 s.The spontaneous ignition process at dynamic high radiant fluxes was recorded and quantified.Two ignition modes were found at the critical radiant flux of 0.4 MW/m^(2),namely hot-gas spontaneous ignition and hot-residue piloted ignition.The latter is not the focus of this paper due to its extremely small probability of occurrence.The research reveals that the increase in flux intensity induces shorter delay times for both pyrolysis and ignition,lower ignition energy density,along with a corresponding rise in the critical mass flux and surface temperature at ignition moment.The simulation results are generally aligned with the experimental findings,despite some divergences may be attributed to model simplifications and parameter assumptions.The work contributes to a deeper insight into material behavior under extreme radiation,with valuable implications for fire safety and hazard assessment.

增程式三缸发动机催化器开裂分析与优化

针对某增程式三缸发动机催化器在耐久性试验中出现的开裂问题,判定断口形式,分析开裂原因,提出优化方案,并进行分析验证。使用化学成分检测、金相组织分析、断口电镜扫描等方式对断口与材料进行了分析,判定断口形式;讨论三缸发动机振动特性,对催化器进行传热分析与热模态分析,通过模态干涉图与应变能密度判定开裂原因;基于模态频率与振型提出对催化器支架的改进方案,并进行分析与验证。研究结果表明,该发动机催化器表面会在高温氧化下形成晶间裂纹,当支架刚度不足时,催化器热模态频率过低,高温状态下会与三缸发动机的3阶燃烧激励发生共振,导致表面裂纹扩展形成断裂;通过分析催化器热模态频率、振型和应变能密度,可有效地对催化器支架进行改进,为三缸发动机的催化器设计提供参考。

Two-stage power system restoration model

In response to the need for robust black-start strategies in modern smart grids during blackouts,this paper proposes a two-stage black-start model that integrates wind turbines(WT),photovoltaic generators(PV),and energy storage systems(ESS).The system restoration path model in the first stage utilizes the Dijkstra algorithm to create a skeleton network and formulate a post-outage generator start-up plan.The second stage involved a load pick-up model,structured as a mixed-integer linear programming problem,aimed at restoring the load with the assistance of the ESS.This stage was designed for computational efficiency,allowing solutions to be obtained using standard commercial solvers.The performance and efficacy of the proposed model were demonstrated through its application to modified IEEE 39/118-bus transmission systems,with the results affirming its high efficiency and effectiveness in power system restoration scenarios.

Study on Influence Factors of Pressure Injury Risk in the Elderly Inpatients with Kidney Disease Based on LASSO Regression

Objective: This paper aims to explore clinical status and related influence factors of pressure injury (PI) in the elderly inpatients with kidney disease, so as to provide reference for the prevention and treatment of PI in the elderly inpatients with kidney disease. Methods: Retrospective collection method is adopted to collect 158 clinical cases of the elderly inpatients with kidney disease aged ≥ 60 in the Nephrology Department, the First Affiliated Hospital of Jinan University from January 2017 to December 2019, and then least absolute shrinkage and selection Operator (LASSO) regression analysis is used to analyze 17 possible influence factors;finally Logistic regression model is established to analyze and screen influence factors of risk. Results: 1) Among 158 elderly inpatients with medium and high risk of PI, the incidence of PI is 20.25%;the most common stage of injury is stage I (42.5%);sacrococcygeal (60%) is the high-risk site of pressure injury. 2) LASSO regression analysis shows that history of present respiratory infection/respiratory failure (β = 1.2714. P < 0.05) and hospitalization time (β = 0.4177. P < 0.05) are independent factors influencing PI risk in the elderly inpatients with kidney disease. Conclusion: The elderly patients with kidney disease and PI risk are the high incidence population of hospital acquired PI;for the elderly inpatients with kidney disease and having respiratory infection history or respiratory failure, prolonged hospitalization will significantly increase the risk of PI. Therefore, targeted preventive and control measures should be taken to reduce the incidence of PI.