Keratograph 5M评估玻璃体切除手术对眼表的影响

目的:该研究旨在应用Keratograph 5M评估玻璃体切除手术(PPV)对眼表的影响。方法:本研究纳入23G玻璃体切除手术的患者30例30眼。分别于手术前、手术后1、2、4、8及12wk行眼表疾病指数(OSDI)问卷评分,采集眼表参数包括泪河高度(TMH)、非侵入性泪膜破裂时间(NITBUT)和眼红指数,并进一步分析各临床参数之间的相关性。结果:玻璃体切除术后4wk内,畏光、异物感较术前显著增加,但是手术后8、12wk降至术前水平;术后1wk眼胀不适较前显著增加,但术后2、4、8及12wk与术前无显著差异。OSDI评分在术后4wk内显著增加,但在术后8wk及12wk降至术前水平。TMH在术后2wk较前增高,但与术前相比差异无统计学意义。首次NITBUT和平均NITBUT在术后8wk内显著缩短,但术后12wk延长至术前水平。眼红指数在术后4wk内显著增加,但术后8wk降至术前水平。首次NITBUT和平均NITBUT在每次随访时间点均呈显著正相关,TMH与平均NITBUT在术后1wk呈显著正相关。结论:Keratograph 5M可作为评估玻璃体切除手术对眼表影响的一种可靠方法。玻璃体切除手术可引起早期眼表症状及体征的改变,但是这些改变在手术后12wk内将逐渐恢复到术前水平。

等径角挤压对AZ80M合金在半固态等温加热过程中液相分布的影响

将经过等径角挤压(ECAP)和未经ECAP的AZ80−0.2Y−0.15Ca(质量分数,%)(AZ80M)合金试样进行半固态等温加热处理,得到两种半固态坯料。对两种坯料的在半固态等温加热处理前后的显微组织进行比较和分析。研究结果表明,在半固态等温加热处理中,经过3道次ECAP(3P)后的试样与初始挤压态试样的液相分布明显不同。半固态处理后的3P试样具有更均匀的液相分布,这是因为其半固态系统中具有更小的二面角。另外,初始挤压态试样和3P试样的固相晶粒粗化过程分别由合并机制和奥斯瓦尔德熟化机制主导。这两种材料在半固态过程中显示出的不同粗化机制主要与大角晶界的占比有关,随着半固态过程的进行,不同的粗化机制会进一步影响液池的演变行为。

钇和钙的添加对镁-空气电池阳极材料AZ80电化学行为和放电性能的影响

研究钇(Y)、钇+钙(Y+Ca)的添加对镁−空气电池阳极材料Mg−8Al−0.5Zn−0.2Mn(AZ80)合金电化学行为和放电性能的影响。结果表明,添加0.2%(质量分数)的Y可以提高AZ80阳极的耐腐蚀性和放电活性。这是因为在AZ80+0.2Y合金基体中分布着细小弥散的球形β-Mg_17)Al_(12)相,可以抑制严重的局部腐蚀和“块状效应”,还有利于α-Mg的快速活化。同时添加0.2%Y和0.15%Ca(质量分数)会使晶粒细化、β-Mg_17)Al_(12)相减少,导致放电电压进一步提高。然而,AZ80+0.2Y+0.15Ca阳极的耐蚀性和阳极效率却不如AZ80+0.2Y,这主要与Mg_17)Al_(12)和Al_(2)Y化合物中掺杂了Ca有关。因此,AZ80+0.2Y阳极表现出优异的综合放电性能,在电流密度为80 mA/cm^(2)时,其放电容量和阳极效率最高,分别为1525 mA·h·g^(−1)和67%,比AZ80合金阳极的分别提高13%和14%。

Lesions of mediodorsal thalamic nucleus reverse abnormal firing of the medial prefrontal cortex neurons in parkinsonian rats

The dysfunction of the medial prefrontal cortex is associated with affective disorders and non-motor features in Parkinson’s disease.However,the exact role of the mediodorsal thalamic nucleus in the function of the prefrontal cortex remains unclear.To study the possible effects of the mediodorsal thalamic nucleus on the neurological function of the medial prefrontal cortex,a model of Parkinson’s disease was established by injecting 8μg 6-hydroxydopamine into the substantia nigra compacta of rats.After 1 or 3 weeks,0.3μg ibotenic acid was injected into the mediodorsal thalamic nucleus of the midbrain.At 3 or 5 weeks after the initial injury,neuronal discharge in medial prefrontal cortex of rat brain was determined electrophysiologically.The numbers of dopamine-positive neurons and tyrosine hydroxylase immunoreactivity in substantia nigra compacta and ventral tegmental area were detected by immunohistochemical staining.Results demonstrated that after injury,the immunoreactivity of dopamine neurons and tyrosine hydroxylase decreased in the substantia nigra compacta and ventral tegmental areas of rats.Compared with normal medial prefrontal cortical neurons,at 3 and 5 weeks after substantia nigra compacta injury,the discharge frequency of pyramidal neurons increased and the discharge pattern of these neurons tended to be a burst-discharge,with an increased discharge interval.The discharge frequency of interneurons decreased and the discharge pattern also tended to be a burst-discharge,but the discharge interval was only higher at 3 weeks.At 3 weeks after the combined lesions,the discharge frequency,discharge pattern and discharge interval were restored to a normal level in pyramidal neurons and interneurons in medial prefrontal cortex.These findings have confirmed that mediodorsal thalamic nucleus is involved in regulating neuronal activities of the medial prefrontal cortex.The changes in the function of the mediodorsal thalamic nucleus may be associated with the abnormal discharge activity of the medial prefrontal cortex neurons after substantia nigra compacta injury.All experimental procedures were approved by the Institutional Animal Care and Use Committee of Xi’an Jiaotong University,China(approval No.XJTULAC2017-067)on August 26,2017.

Effects of quercetin on hyper-proliferation of gastric mucosal cells in rats treated with chronic oral ethanol through the reactive oxygen species-nitric oxide pathway

AIM: To investigate the effect of quercetin (3,3’,4’,5, 7-pentahydroxy flavone), a major flavonoid in human diet, on hyper-proliferation of gastric mucosal cells in rats treated with chronic oral ethanol. METHODS: Forty male Sprague-Dawley rats, weighing 200-250 g, were randomly divided into control group (tap water ad libitum), ethanol treatment group (6 mL/L ethanol), quercetin treatment group (intragastric gavage with 100 mg/kg of quercetin per day), and ethanol plus quercetin treatment group (quercetin and 6 mL/L ethanol). Expression levels of proliferating cell nuclear antigen (PCNA) and Cyclin D1 were detected by Western blot to assay gastric mucosal cell proliferation in rats. To demonstrate the influence of quercetin on the production of extra-cellular reactive oxygen species/ nitrogen species (ROS/RNS) in rats, changes in levels of thiobarbituric acid reactive substance (TBARS), protein carbonyl, nitrite and nitrate (NOx) and nitrotyrosine (NT) were determined. The activity of inducible nitric oxide synthase (NOS) including iNOS and nNOS was also detected by Western blot. RESULTS: Compared to control animals, cell proliferationin the gastric mucosa of animals subjected to ethanol treatment for 7 days was significant increased (increased to 290% for PCNA density P < 0.05, increased to 150 for Cyclin D1 density P < 0.05 and 21.6 ± 0.8 vs 42.3 ± 0.7 for PCNA positive cells per view field), accompanied by an increase in ROS generation (1.298 ± 0.135 μmol vs 1.772 ± 0.078 μmol for TBARS P < 0.05; 4.36 ± 0.39 mmol vs 7.48 ± 0.40 mmol for carbonyl contents P < 0.05) and decrease in NO generation (11.334 ± 0.467 μmol vs 7.978 ± 0.334 μmol P < 0.01 for NOx; 8.986 ± 1.351 μmol vs 6.854 ± 0.460 μmol for nitrotyrosine P < 0.01) and nNOS activity (decreased to 43% P < 0.05). This function was abolished by the co-administration of quercetin. CONCLUSION: The antioxidant action of quercetin relies, in part, on its ability to stimulate nNOS and enhance production of NO that would interact with endogenously produced reactive oxygen to inhibit hyper-proliferation of gastric mucosal cells in rats treated with chronic oral ethanol.

表面抗菌功能涂层的构建及在生物医用材料中的应用研究

近年来,生物医用材料在使用过程中产生的医源性感染问题层出不穷,对人们健康和生命造成严重威胁.表面抗菌涂层构建是解决该类医源性感染问题最有效的策略之一.目前,按照作用机制和功能不同将表面抗菌涂层分为接触式抗菌涂层、抗黏附抑菌涂层、抗黏附杀菌涂层以及智能抗菌涂层.表面抗菌涂层的构建不仅赋予了生物医用材料抗菌性能,有效解决了上述医源性感染问题,还可以提高材料的生物相容性,赋予其抗黏附、抗氧化、生物识别、传感等功能.本文旨在对目前表面抗菌涂层的种类、构建方法以及其在生物医用材料领域中的应用做一全面论述,为进一步开发高性能表面抗菌涂层并扩展其应用提供新思路.

First total synthesis of natural products cajanolactone A and cajanonic acid A

First total synthesis of cajanolactone A and cajanonic acid A has been achieved through steps of anion–anion condensations,cyclization,Williams etherification,selective demethylation,1 3-sigmatropic rearrangement and hydrolysis.This work provides an efficient method for future cajanonic acid A derivatives synthesis.