235 research outputs found
半导体制冷系统性能特性优化
本文探讨一个由n 对结构与性能相同的P型和n型材料集成的半导体元件和两个热交换器组成的半导体制冷系统工作在两个热源之间的优化性能, 获得元件设计的两个优化准则, 并确定工作电流的最佳范围
Immobilization of Charged Colloidal Crystals in a Polymer Matrix
采用光固化技术, 以丙烯酰胺单体与亚甲基双丙烯酰胺交联剂在紫外光的照射下发生光聚合反应, 嵌入聚苯乙烯胶体晶体, 实现了胶体晶体的固定化. 结合反射光谱和Kossel衍射技术研究对照了固定化前后胶体晶体的变化, 实验结果表明, 通过这种水凝胶固定化的胶体晶体保存了未固定前悬浮液中胶体晶体的结构. 但固定化后的胶体晶体的晶面间距和晶体的尺寸都略微减小. 通过对固定化后的水凝胶长时间的反射光谱观测, 发现固定化后胶体晶体在Milli-Q水中起初会发生溶胀, 经过2-5天溶胀-消溶胀过程达到平衡, 平衡后的水凝胶胶体晶体十分稳定, 可以长时间保持胶体晶体的结构. 因此, 胶体晶体固定化不但极大地提高了悬浮液中胶体晶体的抗剪切能力, 还克服了悬浮液中胶体晶体对离子、外界干扰的敏感性, 扩大了胶体晶体的实际应用价值
Mechanism of geniposide in improving free fatty acid metabolism in rats with non-alcoholic fatty liver disease
观察栀子苷改善非酒精性脂肪性肝病的效果,从游离脂肪酸探讨栀子苷调节非酒精性脂肪性肝病的作用机制。健康雄性Wistar大鼠40只,随机分为4组:正常组、模型组、栀子苷组和血脂康组,每组大鼠10只,正常组大鼠给予正常大鼠饲料喂养,其余3组大鼠均采用高脂饲料喂养以诱导非酒精性脂肪性肝病,造模时间为8周,从第5周起至第8周末,栀子苷组和血脂康组分别灌服相应的药物。记录大鼠体重、肝湿重、脂肪质量;用相应方法检测肝组织TG,FFA,FAS,AMPK,ACCase及Malonyl-Co A含量,血清CHO,LDL-C的含量,血清AST,ALT的活性;观察肝脏组织肉眼及病理变化(HE染色法)。结果显示,与正常组相比,模型组大鼠的体重;肝湿重;脂肪重;血清CHO,LDL-C,ALT,AST;肝组织TG,FFA,FAS,ACCase及Malonyl-Co A含量皆显著升高(P<0.01);肝组织AMPK活性显著降低(P<0.01),肝组织肉眼外观及病理切片脂肪变性明显,并出现炎症损伤;与模型组相比,栀子苷组大鼠体重、脂肪质量、肝组织FFA含量、血清ALT,AST活性均显著降低(P<0.01),肝湿重,肝组织TG,FAS,ACCase及Malonyl-Co A含量明显降低(P<0.05),肝组织AMPK活性明显增多(P<0.05),肝脏肉眼外观及病理学表现均有所改善;与模型组相比,血脂康组大鼠的肝湿重、脂肪质量、肝组织TG,FFA和血清LDL-C水平明显降低(P<0.05);与血脂康组相比,栀子苷组大鼠的体重、脂肪质量、肝组织FFA含量均显著降低(P<0.01),其他方面无明显差异。结果表明,栀子苷具有显著的改善高脂饮食诱导的大鼠非酒精性脂肪性肝病的药理效应;其改善大鼠非酒精性脂肪性肝病的游离脂肪酸代谢是通过调节"AMPK-ACCase-Malonyl-Co A-FFA"轴来实现的。To observe the effect of geniposide on non-alcoholic fatty liver disease( NAFLD),and discuss the mechanism of geniposide for NAFLD from the aspect of free fatty acid,forty healthy Wistar male rats were randomly divided into normal group,model group,geniposide and Xuezhikang group. The rats in normal group were fed with normal diets,and the rats in other 3 groups were given with high-fat diet for 8 weeks to induce the NAFLD models. From the week 5 to end of week 8,the rats in geniposide and Xuezhikang group were intervened with corresponding medicines. The body weight,liver wet weight,and fat weight of the rats were recorded.Visual and pathological changes in hepatic tissues were observed with HE staining. The contents of TG,FFA,FAS,AMPK,ACCase and Malonyl-Co A in hepatic tissue,contents of CHO and LDL-C in serum and activities of AST and ALT in serum were detected by using corresponding methods. The results showed that the body weight,liver wet weight,and fat weight of the rats,CHO,LDL-C,ALT and AST levels in serum,TG,FFA,FAS,ACCase and Malonyl-Co A levels in hepatic tissues of the rats in model group were significantly higher than those in normal group( P < 0. 01),while AMPK activity was significantly lower than that of the normal group( P < 0. 01),with obvious visual and pathological steatosis in hepatic tissues,and inflammatory injury occurred in model group. Compared with the model group,body weight of the rat,fat weight,levels of FFA in hepatic tissues,ALT and AST activities in serum,liver wet weight,TG,FAS,ACCase and Malonyl-Co A levels were significantly decreased in geniposide group( P < 0. 01),while the AMPK activity in hepatic tissues was significantly increased( P < 0. 05),with improvement in visual and pathological performance.Compared with the model group,liver wet weight,fat weight,TG and FFA levels in hepatic tissues,and LDL-C level in serum were significantly decreased in Xuezhikang group( P < 0. 05). Compared with Xuezhikang group,the body weight of rat,fat weight and FFA level in hepatic tissues were significantly lower in geniposide group( P < 0. 01),but with no significant difference in other aspects. These findings indicated that geniposide was highly effective in improving the pharmacological effect of NAFLD induced by highfat diet,and the mechanism was achieved through AMPK-ACCase-Malonyl-Co A-FFA axis.国家自然科学基金项目(81274155;81503529);; 福建省自然科学基金项目(2014J01374);; 福建省高等学校新世纪人才计划项目;; 厦门市科技计划项目(3502Z20134020);; 福建省中医药科研项目(WZPW201308
基于深度神经网络的布鲁氏菌病风险预测模型的构建和验证
目的采用深度神经网络算法构建布鲁氏菌病预测模型,提升布鲁氏菌病的早期发现效能。方法纳入2023年呼市职业病防治院收治的202例布鲁氏菌病患者与 319例非布鲁氏菌病患者的临床资料,从中提取性别、年龄、血常规指标及临床诊断等数据进行分析。通过深度神经网络算法构建布鲁氏菌病预测模型,并通过十折交叉验证进行模型优化。模型性能评估指标包括灵敏度、假阴性率、特异度、假阳性率、准确率、阳性预测值、阴性预测值、F1分数、受试者工作特征曲线下面积(AUC)。经评估筛选出的最优模型,借助沙普利可加性解释 (SHAP)方法进行解释,明确模型的决策逻辑与各特征的影响机制。结果数据可视化分析显示,布病组与非布病组数据差异不明显。经十折交叉验证筛选出最优模型展现出良好性能,灵敏度为85.3%、特异度为92.1%、准确率为89.5%、AUC为96.6%,95% CI(0.937,0.977)。SHAP方法解释模型发现年龄、血小板计数、血小板平均体积、嗜碱性粒细胞比例、红细胞分布宽度和绝对嗜碱细胞数,对布病发生具有显著影响。结论本研究构建的深度神经网络预测模型性能良好,能为布病早期诊断与防控提供可靠支持。同时,明确布病相关显著影响特征有助于进一步认识疾病发病机制,该模型未来有望在临床广泛推广
基于空间感知的旅游城市居民游憩忠诚度前因关系研究
公共游憩空间是承载居民日常游憩的主要空间,度量居民对公共游憩空间的忠诚度对改善居民游憩品质具有重要意义。该文以厦门城市居民为实证研究对象,以游憩环境感知与空间感知为潜变量,以游憩满意度为中介变量,通过结构方程模型方法验证、构建旅游城市居民游憩忠诚度前因关系模型。研究结果表明:(1)空间感知对游憩满意度具有正向显著的影响;(2)游憩满意度对游憩忠诚度具有正向显著的影响,且游憩满意度对空间感知和游憩忠诚度的影响关系具有正向显著的中介调节效果;(3)游憩环境感知与游憩忠诚度无显著的直接相关性,但可通过游憩满意度对游憩忠诚度产生间接影响。文章将空间感知引入游憩忠诚度的前因关系模型,在理论上完善了游憩忠诚度形成的动力机制,可作为旅游城市居民政策制定的参考依据。厦门市社会调查项目“厦门市公共游憩空间服务承载力研究”资助~
Separation and identification of auraptene from grapefruit peel oil
橙油素是广泛存在于柑橘类果实中的天然抗癌活性成分。选用SP70大孔吸附树脂分离纯化葡萄柚精油中的橙油素,该树脂对于橙油素的吸附容量和解吸率分别达到14.53 Mg/g和83.32%,并成功地从树脂床层的洗脱液中结晶分离出橙油素晶体。对所得晶体分别采用差示扫描量热仪(dSC)、紫外吸收光谱(uV)、红外吸收光谱(Ir)、电喷雾质谱(ESI-MS)进行定性分析,分析结果与橙油素标准品相符合。进一步采用高效液相色谱(HPlC)对所得晶体进行定量分析,结果表明所得晶体中橙油素的质量分数可达85%。Auraptene exists widely in the peels and juice sacs of citrus species and is reported to be an effective inhibitor of chemical carcinogenesis in some rodent models.The separation and purification of auraptene from the grapefruit peel oil was performed by SP70 macroporous resin adsorption.The amount adsorbed and the recovery of auraptene were 14.53 mg/g and 83.32% respectively.Auraptene was crystallized out from the concentrated eluate of macroporous resin bed successfully.Differential scanning calorimetric(DSC),ultraviolet spectrum(UV),infrared spectroscopy(IR) and electrospray ionization mass spectroscopy(ESI-MS) were all used to analyze the obtained crystals qualitatively.The analytical results are in accordance with that of auraptene standard.Furthermore,high performance liquid chromatography(HPLC) was utilized to quantify auraptene of the crystals obtained.The mass fraction of auraptene in the obtained crystals can reach 85%.福建省新世纪人才支持项目(0000-X04157
类泛素蛋白及其中文命名
泛素家族包括泛素及类泛素蛋白,约20种成员蛋白.近年来,泛素家族领域取得了迅猛发展,并已与生物学及医学研究的各个领域相互交叉.泛素家族介导的蛋白质降解和细胞自噬机制的发现分别于2004和2016年获得诺贝尔奖.但是,类泛素蛋白并没有统一规范的中文译名. 2018年4月9日在苏州召开的《泛素家族介导的蛋白质降解和细胞自噬》专著的编委会上,部分作者讨论了类泛素蛋白的中文命名问题,并在随后的\"泛素家族、自噬与疾病\"(Ubiquitinfamily,autophagy anddiseases)苏州会议上提出了类泛素蛋白中文翻译草案,此草案在参加该会议的国内学者及海外华人学者间取得了高度共识.冷泉港亚洲\"泛素家族、自噬与疾病\"苏州会议是由美国冷泉港实验室主办、两年一度、面向全球的英文会议.该会议在海内外华人学者中具有广泛影响,因此,参会华人学者的意见具有一定的代表性.本文介绍了10个类别的类泛素蛋白的中文命名,系统总结了它们的结构特点,并比较了参与各种类泛素化修饰的酶和它们的生物学功能.文章由45名从事该领域研究的专家合作撰写,其中包括中国工程院院士1名,相关学者4名,长江学者3名,国家杰出青年科学基金获得者18名和美国知名高校华人教授4名.他们绝大多数是参加编写即将由科学出版社出版的专著《泛素家族介导的蛋白质降解和细胞自噬》的专家
Studies of the Formation of Carbon Clusters
通讯作者地址: Huang, RB (通讯作者), Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surface, Xiamen 361005, Peoples R China
地址:
1. Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surface, Xiamen 361005, Peoples R ChinaExperimental and theoretical studies focusing on the formation of carbon clusters are described. In the experiment on discharge in liquid chloroform, a series of perchlorinated fragments of C-60 was synthesized and a scarce amount of C-60 was detected. In the laser vaporization experiments, it was found that the production of C-60(+) and other fullerene ions could be promoted by doping chlorine-containing compounds into carbon targets. Chlorine atoms were found to play key roles of not only tying up the dangling bonds of the polycyclic carbon clusters. but also catalyzing the formation of fullerenes. The results showed that C-60 and other fullerenes are formed from growth of small carbon species and supported the "Pentagon Road" scheme of the fullerene formation mechanism. On the other hand, ab initio calculations were carried out on formation reactions of C-60 from its various perchlorinated fragments, C-60 (2m) Cl-10. The monotonically decreasing calculated energies of reactions with growing size of the fragments confirm that the formation reaction is energetically favourable
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