Delayed xenon post-conditioning mitigates spinal cord ischemia/reperfusion injury in rabbits by regulating microglial activation and inflammatory factors

The neuroprotective effect against spinal cord ischemia/reperfusion injury in rats exerted by delayed xenon post-conditioning is stronger than that produced by immediate xenon post-conditioning. However, the mechanisms underlying this process remain unclear. Activated microglia are the main inflammatory cell type in the nervous system. The release of pro-inflammatory factors following microglial activation can lead to spinal cord damage, and inhibition of microglial activation can relieve spinal cord ischemia/reperfusion injury. To investigate how xenon regulates microglial activation and the release of inflammatory factors, a rabbit model of spinal cord ischemia/reperfusion injury was induced by balloon occlusion of the infrarenal aorta. After establishment of the model, two interventions were given： （1） immediate xenon post-conditioning—after reperfusion, inhalation of 50% xenon for 1 hour, 50% N2/50%O2 for 2 hours; （2） delayed xenon post-conditioning—after reperfusion, inhalation of 50% N2/50%O2 for 2 hours, 50% xenon for 1 hour. At 4, 8, 24, 48 and 72 hours after reperfusion, hindlimb locomotor function was scored using the Jacobs locomotor scale. At 72 hours after reperfusion, interleukin 6 and interleukin 10 levels in the spinal cord of each group were measured using western blot assays. Iba1 levels were determined using immunohistochemistry and a western blot assay. The number of normal neurons at the injury site was quantified using hematoxylin-eosin staining. At 72 hours after reperfusion, delayed xenon post-conditioning remarkably enhanced hindlimb motor function, increased the number of normal neurons at the injury site, decreased Iba1 levels, and inhibited interleukin-6 and interleukin-10 levels in the spinal cord.Immediate xenon post-conditioning did not noticeably affect the above-mentioned indexes. These findings indicate that delayed xenon post-conditioning after spinal cord injury improves the recovery of neurological function by reducing microglial activation and the release of interleukin-6 and interleukin-10.

Ischemic post-conditioning to counteract intestinal ischemia/reperfusion injury

Intestinal ischemia is a severe disorder with a variety of causes.Reperfusion is a common occurrence during treatment of acute intestinal ischemia but the injury resulting from ischemia/reperfusion(IR)may lead toeven more serious complications from intestinal atrophy to multiple organ failure and death.The susceptibility of the intestine to IR-induced injury(IRI)appears from various experimental studies and clinical settings such as cardiac and major vascular surgery and organ transplantation.Where as oxygen free radicals,activation of leukocytes,failure of microvascular perfusion,cellular acidosis and disturbance of intracellular homeo-stasis have been implicated as important factors inthe pathogenesis of intestinal IRI,the mechanisms underlying this disorder are not well known.To date,increasing attention is being paid in animal studies to potential pre-and post-ischemia treatments that protect against intestinal IRI such as drug interference with IR-induced apoptosis and inflammation processes and ischemic pre-conditioning.However,better insight is needed into the molecular and cellular events associated with reperfusion-induced damage to develop effective clinical protection protocols to combat this disorder.In this respect,the use of ischemic post-conditioning in combination with experimentally prolonged acidosis blocking deleterious reperfusion actions may turn out to have particular clinical relevance.

Oxygen Glucose Deprivation Post-conditioning Protects Cortical Neurons against Oxygen-glucose Deprivation Injury: Role of HSP70 and Inhibition of Apoptosis

In the present study, we examined the effect of oxygen glucose deprivation（OGD） post-conditioning（PostC） on neural cell apoptosis in OGD-PostC model and the protective effect on primary cortical neurons against OGD injury in vitro. Four-h OGD was induced by OGD by using a specialized and humidified chamber. To initiate OGD, culture medium was replaced with de-oxygenated and glucose-free extracellular solution-Locke＇s medium. After OGD treatment for 4 h, cells were then allowed to recover for 6 h or 20 h. Then lactate dehydrogenase（LDH） release assay, Western blotting and flow cytometry were used to detect cell death, protein levels and apoptotic cells, respectively. For the PostC treatment, three cycles of 15-min OGD, followed by 15 min normal cultivation, were applied immediately after injurious 4-h OGD. Cells were then allowed to recover for 6 h or 20 h, and cell death was assessed by LDH release assay. Apoptotic cells were flow cytometrically evaluated after 4-h OGD, followed by re-oxygenation for 20 h（O4/R20）. In addition, Western blotting was used to examine the expression of heat-shock protein 70（HSP70）, Bcl-2 and Bax. The ratio of Bcl-2 expression was（0.44±0.08）% and（0.76±0.10）%, and that of Bax expression was（0.51±0.05）% and（0.39±0.04）%, and that of HSP70 was（0.42±0.031）% and（0.72±0.045）% respectively in OGD group and PostC group. After O4/R6, the rate of neuron death in PostC group and OGD groups was（28.96±3.03）% and（37.02±4.47）%, respectively. Therefore, the PostC treatment could up-regulate the expression of HSP70 and Bcl-2, but down-regulate Bax expression. As compared with OGD group, OGD-induced neuron death and apoptosis were significantly decreased in PostC group（P0.05）. These findings suggest that PostC inhibited OGD-induced neuron death. This neuro-protective effect is likely achieved by anti-apoptotic mechanisms and is associated with over-expression of HSP70.

世界竞技体育强国备战巴黎奥运会的举措及启示

在世界百年未有之大变局加速演变背景下,系统梳理世界竞技体育强国备战巴黎奥运会的举措,科学提出备战策略,对提升备战参赛水平具有现实意义。研究认为,美国、英国、法国、日本等国家在运动员选拔、科技驱动、情报搜集、数字备战、基地建设、保障体系等方面采取了针对性备战举措,不断提升训练备战效益。新的国际形势下,大国博弈、俄乌战争等地缘政治冲突和不确定性风险对全球竞技体育的冲击深度蔓延,我国在参赛环境适应、风险防控、运动项目布局、训练节奏调控、参赛规则研判、情报信息收集、科技助力等方面面临新的挑战。研究提出,全面升级参赛风险防控预警机制,提升中国代表团应变能力和保障能力;引导社会多元主体参与奥运备战,分类提升不同项目“赢”的能力;推动数字赋能“全链条”科技助力,提升训练备战科学化、智能化水平;打造项目化、个性化体能训练标准,精准提高运动员专项体能储备;重视信息情报收集与规则研判,塑造良好精神风貌和世界大国形象。

韩国口译研究的主题、热点与前沿

在借鉴Cite Space等相关文献计量方法的基础上,利用Web of Science中的KCI数据库的文献数据,通过关键词共现、聚类分析、战略坐标和关键词突现分析等方法,梳理韩国口译研究的主题、热点与前沿,对韩国口译研究进行结构化解析和图谱式呈现。韩国口译研究的发文时间分布在2002-2022年间,主题有“同声传译”“交替传译”“口译教学”“口译译员”“旅游口译”“司法口译”“医疗口译”“口译策略”等。“译员角色”“口译技巧”“翻译文本”是核心关注点,其研究较为成熟。除此之外,公共服务方面的口译研究在韩国也已较为成熟。“口译策略”目前热度较高,是当今韩国口译领域的研究热点和前沿。

Will the Historic Southeasterly Wind over the Equatorial Pacific in March 2022 Trigger a Third-year La Niña Event?

Based on the updates of the Climate Prediction Center and International Research Institute for Climate and Society(CPC/IRI)and the China Multi-Model Ensemble(CMME)El Niño-Southern Oscillation(ENSO)Outlook issued in April 2022,La Niña is favored to continue through the boreal summer and fall,indicating a high possibility of a three-year La Niña(2020-23).It would be the first three-year La Niña since the 1998-2001 event,which is the only observed three-year La Niña event since 1980.By examining the status of air-sea fields over the tropical Pacific in March 2022,it can be seen that while the thermocline depths were near average,the southeasterly wind stress was at its strongest since 1980.Here,based on a quaternary linear regression model that includes various relevant air-sea variables over the equatorial Pacific in March,we argue that the historic southeasterly winds over the equatorial Pacific are favorable for the emergence of the third-year La Niña,and both the anomalous easterly and southerly wind stress components are important and contribute~50%of the third-year La Niña growth,respectively.Additionally,the possible global climate impacts of this event are discussed.

The Combined Effects of the Tropical and Extratropical Quasi-biweekly Oscillations on the Record-setting Mei-yu Rainfall in the Summer of 2020

During June-July 2020,the strongest recorded mei-yu rainfall occurred in the middle and lower reaches of the Yangtze River.The rainfall processes exhibited an obvious quasi-biweekly(biweekly in brief)variability,and there are altogether five cycles.It is found that the biweekly rainfall cycle mainly arises from the collaborative effects of biweekly variabilities from both the tropics and extratropics.As for the tropics,the biweekly meridional march and retreat of the western Pacific subtropical high(WPSH)is particularly evident.As for the extratropics,geopotential height anomalies near Lake Baikal are active.The former is attributed to the intensified biweekly activity of the southwest-northeast oriented EastAsian Pacific wave train(EAP)originating from the tropical western Pacific,while the latter is associated with the biweekly activities of the eastward propagating Eurasia mid-high latitudinal wave train and the westward propagating North Pacific wave train.Why the biweekly activities of these wave trains intensified is further diagnosed from the perspective of thermodynamical forcing and also from the modulation of interannual background on intraseasonal variability.It is found that the strongest recorded convection anchoring over the tropical western Indian Ocean(IO)triggers anomalous descent over the tropical western Pacific,which modulates the biweekly activity of the EAP.Meanwhile,the anomalous diabatic heating over the IO causes changes of the meridional thermodynamic contrast across the IO to the high latitudes,which modulates the extratropical wave trains.A further diagnosis of barotropic kinetic energy conversion suggests that the active occurrence of two extratropical biweekly wave trains is attributed to the increased efficiency of energy conversion from basic flow.The westward propagation of the extratropical North Pacific wave train is attributed to the weakened and northshifted upper-level westerly,which is caused by the SST warmth near the Kuroshio extension.

基于土柱淋滤实验的煤矸石饱和状态下溶质释放过程研究

针对煤矸石山在降水淋滤作用下对矿区周边地下水造成污染的严重问题,用实验模拟法对包头石拐区一废弃煤矿进行饱和状态下煤矸石的淋滤实验研究。结果表明:煤矸石中Ca、Mg、Fe、Cu、Zn、NO3、SO42、Cl的淋滤过程都遵循浓度先升高再降低到稳定值的基本规律,只是NO3、SO42、Cl的淋出速率明显大于重金属的淋出速率,Ca和Mg、SO42和Cl、Pb和Cr、Cd有相似的淋出机制;重金属最强淋出率从大到小的顺序是Mg>Cd>Ca>Cu>Zn>Cr>Fe>Pb;Hg和As等含量甚微,均未检出。

旅游形象认知的时间顺序对旅游目的地形象认知的影响研究——以银川沙湖与榆林红碱淖为例

旅游者对旅游目的地的形象认知是影响旅游活动的重要因素,对旅游目的地形象定位和市场营销策略的选择都具有重要的参考价值。许多因素对旅游目的地形象认知都产生影响,其中认知的时间特征对旅游目的地形象认知的影响是一个值得关注的新课题:旅游者对不同旅游目的地形象认知的先后顺序对旅游目的地形象认知是否产生影响以及这种影响的程度如何。文章以银川沙湖与榆林红碱淖为例,对旅游者对旅游目的地形象认知中的“先入为主”与“既成事实”效应进行了分析,初步证明旅游者对不同旅游目的地形象感知的先后顺序对旅游目的地形象认知产生影响,并针对案例景区的情况,强调了旅游形象定位与市场营销中的先发优势,提出了自己的观点。

旅游目的地形象认知过程中的“先入为主”与“既成事实”效应研究——以银川沙湖与榆林红碱淖为例

旅游者对旅游目的地的形象认知是影响旅游活动的重要因素,对旅游目的地形象定位和市场营销策略的选择都具有重要的参考价值,逐渐成为旅游研究的新热点。本文选取了我国几个代表性的案例,逐步展开分析,提出若干个相应的假设,据此设计了调查问卷,在兰州、西安两地开展了抽样调查。本文应用国际通用的科学方法和规范模式对抽样调查结果进行分析,根据分析结果对旅游者对旅游目的地形象认知中的“先入为主”与“既成事实”效应进行了探讨,强调了旅游形象定位与市场营销中的先发优势。

基于模糊连接度的抠图样本集构造方法

针对已有的图像抠图采样方法易受trimap输入的影响且精确度不足的问题,提出一种基于模糊连接度的抠图样本集构造方法.通过计算模糊连接度求解未知像素到前景边界和背景边界的最强路径,以与最强路径关联的已知像素为中心搜集邻近的已知像素,并构造出未知像素的样本集,且当新的用户笔画加入后,能够快速地更新样本.实验结果表明,文中方法对trimap的依赖性小、采样精确度高、鲁棒性强.

对KANO模型中质量要素评价倾向判定方法的改进

研究质量要素的KANO模型中,对质量要素评价倾向判定的方法在实际应用中,存在着某些质量要素评价倾向难以判定和不同质量要素评价倾向无法进行比较等问题。本文提出的改进方法基于质量元素的时间特性和统计概率特性,消除评价倾向难以判定的弊端。在此基础上,利用最大领先度的内部、外部和样本规模影响三个方面的性质,推导出度量质量要素评价倾向的指标——质量要素评价倾向归属度。

Moseley定律的意义及其新应用

由Moseley定律可严格定义量子化学中原子轨道线性组合 (LCAO)的基函数 ,其中的屏蔽常数可由实验完全确定。通过最强化学键原理的计算 ,正确给出了水分子的电偶极矩和总电子能量。

大连海域波浪特征研究

根据大连及其附近海域11个站的波浪实测资料,研究分析了大连海域不同岸线段的波浪基本特征,包括常浪向、强浪向及其频率等,绘制了波浪玫瑰图;根据有关文献,对大连海域不同岸线外海深水波浪要素特征进行了分析研究,给出了50a一遇强浪向的波高和周期。结果表明:大连海域在渤海侧强浪向主要为偏北向,黄海侧海域的强浪向主要是偏南向。

转染Chk1 siRNA的人胃癌SGC7901细胞对顺铂的敏感性

目的:探讨Chk1 siRNA对顺铂作用的人胃癌SGC7901细胞增殖及凋亡的影响。方法:构建3个Chk1 siRNA重组载体,分组转染人胃癌SGC7901细胞,采用实时荧光定量PCR方法检测细胞中Chk1 mRNA的表达,应用Western blot检测Chk1蛋白的表达。以效应最强的Chk1 siRNA转染胃癌SGC7901细胞24 h,再用终浓度为10μmol/L的顺铂处理12 h(Chk1 S2+顺铂组)。运用MTT法检测细胞增殖抑制率,TUNEL法检测细胞凋亡。以顺铂处理和未经任何处理的细胞作对照。结果:3条Chk1 siRNA转染SGC7901细胞后,Chk1 mRNA及蛋白表达减弱(P<0.05),以Chk1 S2效应最佳。Chk1 S2+顺铂组SGC7901细胞的增殖抑制率和凋亡指数(AI)均高于顺铂组及对照组(P<0.05)。结论:体外沉默Chk1表达可增强人胃癌SGC7901细胞对顺铂的敏感性。

量子化学计算中的电偶极矩

计算多粒子体系的电偶极矩时,根据最强化学键原理可采用有节面的精确类氢原子轨道(AO)为基函数,而不用径向光滑化的STO和GTO,因此不需作自洽计算.若引入自然晶胞的概念,该原理还可用于有限尺寸的晶体.计算得到水分子的总电子能量和电偶极矩都与实验符合得很好.

基于最强快拍法的自适应副瓣对消技术

由于实战中,电子干扰变化快、起伏大;该种变化将引起副瓣对消性能的严重下降。根据干扰的能量性质,推导出干扰对自相关矩阵的影响。在存在干扰时,自相关矩阵必然存在若干个显著的特征值,大的特征值是由干扰的强能量所致。因此,对回波信号进行能量开窗积累,即可取出最强能量片段,并据此估算自相关矩阵和互相关向量,进行副瓣对消。该方法已应用于某新型监视雷达中。实践表明,与传统副瓣对消技术相比,该方法可显著提升副瓣对消在实战中的对消能力。

基于波束成形的60GHz无线局域网络定位算法

针对60 GHz信号在非视距(NLOS)环境下测距困难的问题,提出一种基于波束成形的60 GHz无线局域网络(WLAN)定位算法。首先,通过借助波束成形技术进行最强路径搜索,波束成形算法将天线的最大增益方向指向接收最强多径信号的方向,在增强搜索鲁棒性的同时扩大了定位覆盖范围;然后,对NLOS条件下的时延偏差进行建模,重构NLOS测量数据;最后,为进一步提高定位精度,设置检测阈值,引入异常值检测机制。采用Matlab仿真平台在STAs-STAs信道模型进行仿真,结果表明,NLOS环境下基于传统相干估计的到达时间(TOA)定位算法的定位误差约为2 m,定位成功率仅为0.5%,而采用基于波束成形的60 GHz定位算法后,定位误差降低至1.02 cm,定位成功率高达94%。因此,波束成形技术为NLOS环境下的60 GHz定位提供了解决思路,有效地提高了60 GHz室内定位精度和定位成功率。

“太平洋十年涛动”冷位相时期的全球飓风等灾害

本文揭示了冷气候、飓风、强潮汐、流行性感冒世界大流行和强震相互对应的物理机制,对气候及其相关灾害的预测有重大科学意义。规律表明,在“拉马德雷”冷位相时期,全球强震、低温、飓风伴随拉尼娜、全球性流感伴随厄尔尼诺将越来越强烈。面对日益增大的全球灾害,海洋预报意义重大。

概率强近邻在IMM中的应用

目标的幅度信息在数据关联技术中起着很重要的作用,但传统的方法忽视了对这类信息的应用。提出了一种基于概率强近邻的相互作用多模型算法,有效地将幅度信息引入到数据关联中,完成对目标的精确跟踪。通过仿真,将它与传统的相互作用多模型概率数据关联等算法进行比较。仿真结果表明,该算法不仅具有很好的跟踪精度,而且其计算量也大大降低。