基于金银纳米材料光学传感器的构建及其在食品安全快速检测中的应用

当前,农兽药残留、重金属污染和食源性病菌等是主要的食品安全问题,常规检测方法存在操作烦琐、预处理要求高等局限性,因此急需开发一种效率高、速度快、成本低的食品安全检测方法。贵金属纳米材料(金、银)具有良好的光学性能、化学稳定性、高催化活性、高导电性等优点,基于其构建的光学传感器具有高灵敏度、强特异性、低成本等显著优势,可用于食品安全的高效、快速、灵敏检测。本文综述了金银纳米材料及金-银复合纳米材料的制备方法及其光学传感器的构建策略,重点阐述了基于金银纳米材料的光学传感器在食品安全中快速检测的应用。本文分析了光学传感器存在的问题,并对其发展前景进行了展望,以期为金银纳米材料构建光学传感器及其在食品安全检测中的应用提供理论依据和技术支持。

超低渗透砂岩油藏水平井同井同步注采补能方法——以鄂尔多斯盆地长庆油田为例

针对超低渗透砂岩油藏水平井中段难以建立有效水驱驱替压力系统问题,提出在同一口水平井上采用封隔器、密封插管等工具,实现部分压裂缝注水、部分压裂缝采油,在同一水平井内形成分段同步注采的补能新方法,即水平井同井同步注采。该方法可缩小注入端与采出端的距离,快速建立有效水驱驱替系统;该方法将井间驱替转变为水平井段间驱替,将点状水驱转变为线状均匀水驱,可大幅提高水驱波及体积,缩短见效周期。研究表明:①超低渗透砂岩油藏水平井同井同步注采,注水段应选择天然裂缝方向与人工裂缝方向一致或天然裂缝不发育的层段,段间距60~80 m;②水平井同井同步注采除控制注入压力外,采用周期注水可降低随注水时间延长注水压力逐渐上升导致的地层天然裂缝开启、生长或地层破裂风险;③现场试验验证,水平井同井同步注采补能方法可有效提升单井产量且经济效益良好,可大规模应用于超低渗透砂岩油藏的开发。

超低渗透油藏水平井缝间异步周期注采补能技术

由于超低渗透砂岩油藏水平井缺乏补充能量的有效手段,为此提出水平井同井缝间轮换注采工艺。该工艺管柱由丢手接头、Y445封隔器、Y341封隔器、单向配注器、单向配产器、脱卡器组成,可实现部分压裂缝注水、部分压裂缝采油,在同一口水平井内实现分段异步注采补能。缝间异步注采增油是水驱、弹性驱、渗吸多种驱动机理综合作用的结果,相比传统的面积注水井网,更容易形成有效驱动。研究表明:水平井同井缝间异步周期注采补能方法采用水力压裂裂缝注水,油藏吸水面积大幅度增加;流场形状由径向渗流转变为线性渗流;缩短注入端与采出端的距离,提高了驱替压力梯度,有效渗透率也随之增大,这些机制综合作用起到了增油的效果。现场试验表明,水平井同井缝间异步周期注采补能方法能有效提升单井产量,可在超低渗砂岩油藏规模推广。

基于甲氧肉桂酸衍生物光控分子构建光响应蠕虫状胶束的结构性质关系

本文利用十六烷基三甲基氢氧化铵和不同结构的甲氧基取代的肉桂酸衍生物构建了光响应蠕虫状胶束体系,研究了甲氧取代基的位置和数量对蠕虫状胶束结构与光响应性的影响。研究发现,肉桂酸衍生物通过将其芳香环插进胶束内核促进了蠕虫状胶束的形成。相较于甲氧基的位置,甲氧基的数量对所形成蠕虫胶束结构的影响更为显著,因为引入的甲氧基会增大表面活性剂与肉桂酸衍生物之间的空间位阻,不利于更大聚集体的形成。在光诱导蠕虫状胶束结构转变的过程中,甲氧基的取代位置则更为重要。总体而言,含有邻位甲氧基的肉桂酸衍生物体系的转变过程较快,而间位和对位甲氧基取代的肉桂酸衍生物体系的转变则较慢。

临床医学导师制在卓越医生培养过程中的作用

目的:探索临床医学导师制在卓越医生培养过程中的作用。方法:在山西医科大学临床医学本科生中设立“卓越医师培养试验班”实施导师制,并逐步推广至所有临床医学本科生中,观察学习情况及成果。结果:实行导师制的学生参加多项国际项目交流,获得多项省级以上、校级项目立项,多次在大学生创新创业大赛获奖,在大学生临床技能大赛中取得了好成绩。结论:与往届未实行导师制的临床本科生相比,实行导师制后学生们的学习积极性大大提高,在教育改革、临床技能操作、治疗方法思考等方面有显著提升。导师制对于卓越医生的培养有积极意义。

氧化应激机制在盆腔器官脱垂中的研究进展

氧化应激是机体内活性氧(ROS)和抗氧化剂失衡引起的一种应激反应,近年研究发现氧化应激与盆腔器官脱垂(POP)的发病密切相关。POP是由于盆底肌肉、韧带及筋膜组织损伤所致的一种妇科常见病,是影响女性生活质量的五大慢性病之一,还是导致女性性功能障碍(FSD)的主要器质性疾病。研究发现POP的多种危险因素均可导致氧化应激损伤,并且POP患者的盆底主要支持组织中表现出显著的氧化应激特征,说明过量的ROS可能通过氧化损伤、影响胶原代谢和促细胞凋亡等机制及相关信号通路不同程度的影响盆底组织结构功能。研究氧化应激在POP中的作用,不仅有助于揭示POP的发病机制,也将为POP的防治提供一种新思路。

Berberine inhibits hepatic gluconeogenesis via the LKB1-AMPK-TORC2 signaling pathway in streptozotocin-induced diabetic rats

AIM: To investigate the molecular mechanisms of berberine inhibition of hepatic gluconeogenesis in a diabetic rat model.METHODS: The 40 rats were randomly divided into five groups. One group was selected as the normal group. In the remaining groups(n = 8 each), the rats were fed on a high-fat diet for 1 mo and received intravenous injection of streptozotocin for induction of the diabetic models. Berberine(156 mg/kg per day)(berberine group) or metformin(184 mg/kg per day)(metformin group) was intragastrically administered to the diabetic rats and 5-aminoimidazole-4-carboxamide1-β-D-ribofuranoside(AICAR)(0.5 mg/kg per day)(AICAR group) was subcutaneously injected to the diabetic rats for 12 wk. The remaining eight diabetic rats served as the model group. Fasting plasma glucose and insulin levels as well as lipid profile were tested.The expressions of proteins were examined by western blotting. The nuclear translocation of CREB-regulated transcription co-activator(TORC)2 was observed by immunohistochemical staining. RESULTS: Berberine improved impaired glucose tolerance and decreased plasma hyperlipidemia. Moreover, berberine decreased fasting plasma insulin and homeostasis model assessment of insulin resistance(HOMA-IR). Berberine upregulated protein expression of liver kinase(LK)B1, AMP-activated protein kinase(AMPK) and phosphorylated AMPK(p-AMPK). The level of phophorylated TORC2(p-TORC2) protein in the cytoplasm was higher in the berberine group than in the model group, and no significant difference in total TORC2 protein level was observed. Immunohistochemical staining revealed that more TORC2 was localized in the cytoplasm of the berberine group than in the model group. Moreover, berberine treatment downregulated protein expression of the key gluconeogenic enzymes(phosphoenolpyruvate carboxykinase and glucose-6-phosphatase) in the liver tissues. CONCLUSION: Our findings revealed that berberine inhibited hepatic gluconeogenesis via the regulation of the LKB1-AMPK-TORC2 signaling pathway.

Berberine reverses free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKβ

AIM: To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-L1 adipocytes. METHODS: The model of insulin resistance in 3T3-L1 adipocytes was established by adding palmic acid (0.5 mmol/L) to the culture medium. Berberine treatment was performed at the same time. Glucose uptake rate was determined by the 2-deoxy-[3H]-D-glucose method. The levels of IkB kinase beta (IKKβ) Ser181 phosphorylation, insulin receptor substrate-1(IRS-1) Ser307 phosphorylation, expression of IKKβ, IRS-1, nuclear transcription factor kappaB p65 (NF-κB p65), phosphatidylinositol-3-kinase p85 (PI-3K p85) and glucose transporter 4 (GLUT4) proteins were detected by Western blotting. The distribution of NF-κB p65 proteins inside the adipocytes was observed through confocal laser scanning microscopy (CLSM). RESULTS: After the intervention of palmic acid for 24 h, the insulin-stimulated glucose transport in 3T3-L1 adipocytes was inhibited by 67%. Meanwhile, the expression of IRS-1 and PI-3K p85 protein was reduced, while the levels of IKKβ Ser181 and IRS-1 Ser307 phosphorylation, and nuclear translocation of NF-κB p65 protein were increased. However, the above indexes, which indicated the existence of insulin resistance, were reversed by berberine although the expression of GLUT4, IKKβ and total NF-κB p65 protein were not changed during this study. CONCLUSION: Insulin resistance induced by FFAs in 3T3-L1 adipocytes can be improved by berberine. Berberine reversed free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKβ.

地方政府环境保护支出竞争的空间效应研究

中国式财政分权为地方政府的财政支出竞争创造了可能。基于策略互动的视角,使用30个省级地区2007-2016年的面板数据,采用莫兰指数、局部莫兰指数和空间杜宾模型方法,实证检验了地方政府间环境保护支出竞争的存在,以及环境保护支出竞争对环境污染的空间效应。研究结果表明:地方政府在环境保护支出方面存在竞争,环境保护已不再像其他非经济性公共品一样容易被地方政府忽视,地方政府间的环境保护支出竞争为策略模仿行为;同时,环境保护支出竞争存在空间溢出效应。进一步分析发现,地理相邻的地方政府间的环境保护支出有利于降低本地区的污染物排放。由此,改变政绩考核机制,加大环保支出、优化产业结构、降低污染排放、充分利用市场机制及公众参与环保监督、探索地方政府环境污染区域协调治理方式是改善环境状况的重要政策选择。

Effects of decompression joint Governor Vessel electro-acupuncture on rats with acute upper cervical spinal cord injury

Decompression is the major therapeutic strategy for acute spinal cord injury,but there is some debate about the time window for decompression following spinal cord injury.An important goal and challenge in the treatment of spinal cord injury is inhibiting or reversing secondary injury.Governor Vessel electroacupuncture can improve symptoms of spinal cord injury by inhibiting cell apoptosis and improving the microenvironment of the injured spinal cord.In this study,Governor Vessel electroacupuncture combined with decompression at different time points was used to treat acute spinal cord injury.The rat models were established by inserting a balloon catheter into the atlanto-occipital space.The upper cervical spinal cord was compressed for 12 or 48 hours prior to decompression.Electroacupuncture was conducted at the acupoints Dazhui(GV14) and Baihui(GV 20)(2 Hz,15 minutes) once a day for 14 consecutive days.Compared with decompression alone,hind limb motor function recovery was superior after decompression for 12 and 48 hours combined with electroacupuncture.However,the recovery of motor function was not significantly different at 14 days after treatment in rats receiving decompression for 12 hours.Platelet-activating factor levels and caspase-9 protein expression were significantly reduced in rats receiving electroacupuncture compared with decompression alone.These findings indicate that compared with decompression alone,Governor Vessel electroacupuncture combined with delayed decompression(48 hours) is more effective in the treatment of upper cervical spinal cord injury.Governor Vessel electroacupuncture combined with early decompression(12 hours) can accelerate the recovery of nerve movement in rats with upper cervical spinal cord injury.Nevertheless,further studies are necessary to confirm whether it is possible to obtain additional benefit compared with early decompression alone.

Saliva in the diagnosis of diseases

Saliva is secreted from the salivary glands and has multiple functions, including mouth cleaning and protection, antibacterial effects and digestion. With the rapid advancement in salivaomics, saliva is well recognized as a pool of biological markers.Saliva, as a non-invasive and safe source, could be a substitute for blood in the diagnosis and prognosis of diseases. This review summarizes the latest advancements in saliva-related studies and addresses the potential value of saliva in the early diagnosis of oral diseases, such as dental caries and periodontal disease, as well as cancer, diabetes and other systemic disorders. Saliva biomarkers range from changes in the biochemical indices of DNA, RNA and proteins to the diversi?cation of microbiota structures. This study integrates data reported in the recent literature and discusses the clinical signi?cance and prospects for the application of saliva in the early diagnosis of diseases, translational medicine and precision medicine.

Validation and application of three-dimensional discontinuous deformation analysis with tetrahedron finite element meshed block

In the last decade, three dimensional discontinuous deformation analyses (3D DDA) has attracted more and more attention of researchers and geotechnical engineers worldwide. The original DDA formulation utilizes a linear displacement function to describe the block movement and deformation, which would cause block expansion under rigid body rotation and thus limit its capability to model block deformation. In this paper, 3D DDA is coupled with tetrahedron finite elements to tackle these two problems. Tetrahedron is the simplest in the 3D domain and makes it easy to implement automatic discretization, even for complex topology shape. Furthermore, element faces will remain planar and element edges will remain straight after deformation for tetrahedron finite elements and polyhedral contact detection schemes can be used directly. The matrices of equilibrium equations for this coupled method are given in detail and an effective contact searching algorithm is suggested. Validation is conducted by comparing the results of the proposed coupled method with that of physical model tests using one of the most common failure modes, i.e., wedge failure. Most of the failure modes predicted by the coupled method agree with the physical model results except for 4 cases out of the total 65 cases. Finally, a complex rockslide example demonstrates the robustness and versatility of the coupled method.

Berberine Inhibits Gluconeogenesis in Skeletal Muscles and Adipose Tissues in Streptozotocin-induced Diabetic Rats via LKB1-AMPK-TORC2 Signaling Pathway

The effect and potential molecular mechanisms of berberine on gluconeogenesis in skeletal muscles and adipose tissues were investigated.After adaptive feeding for one week,8 rats were randomly selected as the normal group and fed on a standard diet.The remaining 32 rats were fed on a high-fat diet and given an intravenous injection of streptozotocin(STZ)for 2 weeks to induce the diabetic models.The diabetic rat models were confirmed by oral glucose tolerance test(OGTT)and randomly divided into 4 groups(n=8 each),which were all fed on a high-fat diet.Berberine(3 g/kg per day)or metformin(183 mg/kg per day)was intragastrically administered to the diabetic rats for 12 weeks,serving as berberine group and metformin group respectively.5-aminoimidazole-4-carboxamide1-β-D-ribofuranoside[AICAR,an agonist of AMP-activated protein kinase(AMPK),0.5 mg/kg per day]was subcutaneously injected to the diabetic rats for 12 weeks,serving as AICAR group.The remaining 8 diabetic rats served as the model group,which was given a 0.5%carboxyl methylcellulose solution by oral gavage.Fasting serum insulin(FINS),OGTT as well as lipid parameters were tested by commercial kit.The protein levels of liver kinase B1(LKB1),AMPK,phosphorylated AMP-activated protein kinase(p-AMPK),transducer of regulated CREB activity 2(TORC2),phosphorylated transducer of regulated CREB activity 2(p-TORC2),phosphoenolpyruvate carboxykinase(PEPCK),and glucose-6-phosphatase(G6Pase)in skeletal muscles and adipose tissues were examined by Western blotting.The results showed that berberine significantly decreased the body weight,plasma glucose,insulin levels,and homeostatic model assessment for insulin resistance(HOMA-IR)of diabetic rats compared with those in the model group.Meanwhile,the serum total triglyceride(TG),total cholesterol(TC),and low-density lipoprotein cholesterol(LDL-C)levels were markedly decreased and high-density lipoprotein cholesterol(HDL-C)level was significantly increased after the treatment with berberine.In addition,we found that berberine significantly increased the expression of p-AMPK and LKB1,while decreasing the p-TORC2 levels in skeletal muscles and adipose tissues.Moreover,the expression of PEPCK and G6Pase was significantly down-regulated after the treatment with berberine compared to the model group.It was suggested that the mechanism by which berberine inhibited peripheral tissue gluconeogenesis may be attributed to the activation of the LKB1-AMPK-TORC2 signaling pathway.

肠道短链脂肪酸与肠黏膜屏障

短链脂肪酸(short-chain fatty acids,SCFAs)包括乙酸、丙酸、丁酸等,是肠道菌群的代谢产物,它对肠黏膜上皮细胞作用广泛,包括能量供应、免疫调节、调控肠道炎症、肠-脑轴等。目前,肠道SCFAs与肠黏膜屏障的关系尚未明确,本文主要从SCFAs来源、生理功能、肠道主要SCFAs对肠黏膜屏障的作用等方面进行概述,为深入研究和可能的临床应用提供帮助。

为环保而竞争:地方政府竞争的新解析

财政分权体制产生的激励机制催生了地方政府间为增长而竞争的局面,为增长而竞争在推动中国经济发展的同时,也通过放松环境监管标准、减少环境保护投入和削弱环保部门独立性加剧了环境问题的严重性。随着中国经济进入新常态、国税地税征管体制改革、考核问责机制的修正以及民众环保意识的觉醒,中央政府逐渐引导地方政府由为增长而竞争向为环保而竞争转型。然而,为环保而竞争目标的实现除了使地方政府具备积极进行环境治理的动机外,还需要改革财政体制,完善生态补偿机制、长效环保问责制度、探索区域协调治理模式来配合实现。

Salivary protease spectrum biomarkers of oral cancer

Proteases are important molecules that are involved in many physiological and pathological processes of the human body,such as growth,apoptosis and metastasis cancer cells.They are potential targets in cancer diagnosis and biotherapy.In this study,we analyzed the salivary protease spectrum of patients with oral squamous cell carcinoma (OSCC),oral benign masses and chronic periodontitis,as well as that of health,using human protease array kits,enzyme-linked immunosorbent assay,western blot and immunofluorescence.The salivary protease spectrum was found to be associated with oral diseases.For example,the saliva of patients with OSCC contained increased numbers of proteases than those of other oral diseases and health.The levels of matrix metalloproteinase (MMP)-1,MMP-2,MMP-10,MMP-12,A disintegrin and metalloprotease (ADAM)9,A disintegrin and metalloprotease with thrombospondin type 13 motifs (ADAMST13),cathepsin V and kallikrein 5 in the saliva of patients with OSCC were significantly increased compared with those of other groups.Taking MMP-1,cathepsin V,kallikrein 5 and ADAM9 as biomarkers of OSCC,cutoff values were199,11.34,9.29 and 202.55 pg·mL?1,respectively.From the area under the curve,sensitivity and specificity,the combination of cathepsin V/kallikrein5/ADAM9 was an optimal biomarker for diagnosing OSCC.Thus,analysis of the salivary protease spectrum may be an innovative and cost-efficient approach to evaluating the health status of the oral cavity.Specifically,increases in cathepsin V,kallikrein 5 and ADAM9 may be useful biomarkers in the screening and diagnosis of OSCC.

微RNA-125b靶向调控M2型丙酮酸激酶影响宫颈癌SiHa细胞机制验证

目的探讨宫颈癌细胞中微RNA(miR)-125b和M2型丙酮酸激酶(PKM2)的表达以及miR-125b对PKM2基因的调控作用,从而确定miR-125b下游调控的靶基因,阐明其在宫颈癌发生发展中可能的分子机制。方法培养宫颈癌SiHa细胞及正常上皮细胞(293T细胞),利用细胞转染技术过表达或沉默miR-125b。实验分为实验组:miR-125b mimics(M组)、miR-125b inhibitor(I组);阴性对照组:miR-125b mimics negative con-trol(MNC组)、miR-125b inhibitor negative control(INC组);空白对照组(B组):未进行转染。采用实时荧光定量-聚合酶链反应(qRT-PCR)检测各组细胞中miR-125b的含量。采用免疫荧光及蛋白质印迹法检测各组细胞中PKM2蛋白的表达。结果与293T细胞相比,宫颈癌SiHa细胞中miR-125b的表达下调(0.82±0.05)(P<0.05),PKM2表达上调(3.4±0.5)倍(P<0.05)。SiHa细胞转染成功后,免疫荧光检测miR-125b模拟物组表达PKM2蛋白的细胞数目(1.0±0.7)低于模拟物阴性对照组表达PKM2蛋白的细胞数目(3.6±0.5)(P<0.05);miR-125b抑制物组中表达PKM2蛋白的细胞数目(6.0±0.7)高于抑制物阴性对照组表达PKM2蛋白的细胞数目(3.6±1.3)(P<0.05)。蛋白质印迹法检测miR-125b模拟物组的PKM2蛋白相对表达量(0.239±0.042)低于模拟物阴性对照组的PKM2蛋白相对表达量(0.314±0.018)(P<0.05);miR-125b抑制物组的PKM2蛋白表达水平(0.40±0.03)高于抑制物阴性对照组的PKM2蛋白表达水平(0.34±0.04)(P<0.05)。结论与正常上皮细胞相比,宫颈癌SiHa细胞中miR-125b表达下调,而PKM2蛋白表达上调;宫颈癌细胞中miR-125b表达下调可能会通过增加PKM2的表达,从而增强其糖酵解作用,促进肿瘤的生长。

地方政府财政环保支出竞争的演化博弈分析

随着生态文明建设的持续推进,地方政府生态环保意识和行为发生了积极变化,环境保护不再像其他公共物品一样容易被忽视,实施环境治理完成环保任务成为地方政府的重要工作目标。采用演化博弈分析方法,引入环境问责、环保绩效考核等作为中央政府约束机制的指标,构建地方政府财政环保支出竞争博弈模型,得到影响地方政府财政环保支出竞争博弈行为的关键因素。结果表明:一是地方政府的财政环保支出存在竞争行为;二是地方政府财政环保支出竞争行为受到治污成本、环境治理效果、污染排放量、外部效应、中央政府的环境问责及环保绩效考核等因素影响;三是在中央政府约束机制下,地方政府财政环保支出竞争的表现形式向“逐顶竞争”转变,从而带来区域环境质量的整体改善。

Performance analysis of mobile ad hoc networks under flooding attacks

Due to their characteristics of dynamic topology, wireless channels and limited resources, mobile ad hoc networks are particularly vulnerable to a denial of service (DoS) attacks launched by intruders. The effects of flooding attacks in network simulation 2 (NS2) and measured performance parameters are investigated, including packet loss ratio, average delay, throughput and average number of hops under different numbers of attack nodes, flooding frequency, network bandwidth and network size. Simulation results show that with the increase of the flooding frequency and the number of attack nodes, network performance sharply drops. But when the frequency of flooding attacks or the number of attack nodes is greater than a certain value, performance degradation tends to a stable value.

<i>Helicobacter</i>infection decreases basal colon inflammation, but increases disease activity in experimental IBD

Background: Helicobacter species are best known for their roles in the pathology of gastritis;however, several Helicobacter species also colonize the intestine, and less is known about effects of Helicobacter on the development of intestinal inflammation. To evaluate contributions of Helicobacter in inflammatory bowel disease, we investigated whether and how pre-existing intestinal colonization would affect disease severity and biomarkers of inflammation in experimental IBD. Materials and Methods: Mice were infected with H. muridarum 2 weeks prior to induction of colitis mediated by 3% dextran sulfate (DSS). Disease activity index, stool blood and consistency, colon length, myeloperoxidase, histopathology, blood and lymphatic vessels, and numbers of dilated mucosal crypts were measured in control, DSS-only, H. muridarum-infected, and H. muridarum-infected + DSS mice. Results: Prior to DSS challenge, H. muridarum-infected mice showed little distal gut injury by several indices of colon inflammation with decreased blood vessel density in the submucosa, and lower lymphatic density in the mucosa and submucosa. However, after DSS colitis, H. muridarum-infected mice exhibited significantly greater disease. Weight change, stool bleeding, diarrhea, and angiogenesis were all increased in H. muridarum-infected mice in DSS colitis compared to DSS controls. Conclusions: Our data show that Helicobacter colonization of the intestine, unlike that of the stomach, lowers basal gut inflammatory scores, but increases disease activity and inflammation in an acute colitis model. Intestinal Helicobacter infection may therefore represent a significant sub-clinical factor which predisposes the gut to inflammatory injury.