In vitro investigations on retention force behavior of conventional and modern double crown systems

ObjectiveThis study aimed to investigate the effects of long-term use on the retention force and wear behavior of double crown systems.MethodsBased on a common double crown design sixty pairs of telescopic crowns were fabricated and divided into six groups, each consisting ten samples: “Gold standard” cast gold alloy primary and secondary crown (GG) and cast non-precious alloy (NN), computer-aided design (CAD)/computer-aided manufacturing (CAM)-milled zirconia primary crown and galvanoformed secondary crown (ZG), CAD/CAM-milled non-precious alloy primary and secondary crown (CC NN), CAD/CAM-milled zirconia primary crown and non-precious alloy secondary crown (CC ZN) and CAD/CAM-milled zirconia primary crown and polyetheretherketone (PEEK) secondary crown (CC ZP). In the constant presence of artificial saliva, all samples were subjected to 10,000 joining-separation cycles at a velocity of 120 mm/min. Wear was analyzed by reflected light microscopy and confocal microscopy before and after artificial aging.ResultsRetention force losses were observed in each group after long-term use, with significant losses in the groups ZG and CC ZP (p_ZG = 0.01, p_{CC ZP} = 0.049). During artificial aging, no significant differences in pull-off force were recorded for groups GG, NN and CC ZN. Regarding wear, merely the Y-TZP primary crowns of the CC ZP group displayed no surface changes.SignificanceAll tested production methods and material combinations seem to be suitable for clinical practice. CAD/CAM technology allows similarly predictable results to be achieved as the gold standard. Confocal microscopy is recommended for surface examinations of double crowns.     

护理学基础理论课混合式“金课”的建设

目的探讨护理学基础理论课程混合式“金课”教学模式及实施效果。方法便利抽取2017级护理本科生(211名)为试验组,在护理学基础理论教学中采用混合式“金课”教学模式,依据“金课”标准从教学前期设计、创设教学情境、开展混合教学活动、课程考核评价进行教学改革,其中混合式教学包括课前自学、课堂互动和课后巩固;2016级护理本科生(238名)为对照组,进行课堂理论教学。课程结束后评价试验组学生线上学习完成情况及比较两组课程成绩、学生自主学习能力及教学满意度。结果试验组的课程平台点击率超过10万次,学生学习任务的完成率超过95%,试验组的期末考试成绩、自主学习能力总分和各维度得分、教学满意度均高于对照组(P<0.001),89.10%学生对课程教学满意。结论混合式“金课”教学在护理学基础理论教学中取得了较好成效。教师应以“金课”为标准进行课程改革,对课前、课中、课后进行全方位课程建设,打造有高阶性、创新性、挑战度的“金课”。     

Effects of Phonophoresis and Gold Nanoparticles in Experimental Model of Muscle Overuse: Role of Oxidative Stress

The aim of the study described here was to investigate the effects of pulsed ultrasound and gold nanoparticles (AuNPs) on behavioral, inflammatory and oxidative stress parameters in an experimental model of overuse. Wistar rats performed 21 d of exercise on a treadmill at different intensities and were exposed to ultrasound in the presence or absence of AuNPs. The overuse model promoted behavioral changes and increased creatine kinase, superoxide dismutase and glutathione peroxidase activity, as well as the levels of superoxide, nitrotyrosine, nitric oxide, thiobarbituric acid reactive substance, carbonyl, tumor necrosis factor α and interleukin-6. These values were significantly decreased by AuNPs and by AuNPs plus ultrasound. Catalase activity remained unchanged and the glutathione level increased significantly after exposure to AuNPs plus ultrasound. These results suggest a susceptibility to anxiety as well as elevated levels of oxidative stress. However, therapeutic interventions with AuNPs plus ultrasound reduced the production of oxidants and oxidative damage and improved the anti-oxidant defense system.     

Have traditional DMARDs had their day?

This review tries to answer the question of whether in the face of the recently introduced biologics conventional disease-modifying antirheumatic drugs (DMARDs) can still be recommended in the treatment of rheumatoid arthritis (RA). We start with an overview of the oldest conventional DMARD, injectable gold (Au), which was introduced in the treatment of RA in the 1920s. The effect of gold is directed at a number of different sites of the immune system. A significant improvement of clinical and biochemical disease activity parameters as well as an inhibition of X-ray progression has been shown in many studies. Head-to-head comparisons between gold and high-dose methotrexate (MTX) demonstrated no significant difference but some advantages for gold. Since trials comparing biologics with gold will never be performed, an indirect comparison was done by analyzing the results of trials with gold with those with biologics. Conclusions from such comparisons have to be drawn with caution especially since the methodology for performing trials has changed with time. We selected four trials with gold (two open, one placebo-controlled, and one comparison with MTX) and five trials with biologics (three placebo-controlled, one dose escalation study, and one comparison with MTX). In all these trials baseline data regarding swollen joint count (SJC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were roughly comparable and, with the exception of interleukin (IL)-1 RA, demonstrated a similar improvement of over 50% already after 6 months [with faster onset with tumor necrosis factor (TNF)-alpha blockade]. American College of Rheumatology (ACR) response data were not available for the older gold trials. European League Against Rheumatism (EULAR) response criteria could be calculated for the Au/MTX trial and were—for these compounds—only slightly inferior to the results with adalimumab. X-ray response is especially difficult to compare across studies. Although an inhibition with Au and MTX could be demonstrated, this occurred—similar to corticosteroid treatment—earlier and more pronounced with TNF-alpha blockers. We confirm the statement of Weinblatt that the most modern DMARDs do not appear to be much better than the oldest one indicating that conventional DMARDs are not outdated. Therefore, a sufficient trial of conventional DMARDs should precede the introduction of treatment with the very expensive biologics.     

金纳米团簇诱导小鼠体内毒性的性别差异

目的 研究金纳米团簇诱导的小鼠体内毒性是否有性别差异.方法 首先制备谷胱甘肽保护的金纳米团簇(GSH-Au NCs)和牛血清白蛋白保护的金纳米团簇(BSA-Au NCs),然后将48只雌雄各半的昆明鼠随机分为对照组、GSH-Au NCs给药组和BSA-Au NCs给药组.给药组每只小鼠腹腔注射0.2 ml金纳米团簇,对照组注射等量生理盐水;28 d后通过免疫指数、血常规和生化指标来评价金纳米团簇诱导的体内毒性是否有性别差异.结果 2实验组的雌雄小鼠的红细胞和白细胞都有所改变.BSA-Au NCs组的雌性小鼠的胸腺指数有明显增加,其差异有统计学意义(P＜0.05).GSH-Au NCs组的雌性小鼠的谷草转氨酶有所升高,BSA-Au NCs组的雄性小鼠的谷丙转氨酶略有升高;2实验组小鼠的肌酐有明显变化,其差异有统计学意义(P＜0.05).结论 BSA-Au NCs组的雌性小鼠受到的免疫反应更明显,2实验组的雌雄小鼠受到相似的感染及炎症,雌雄小鼠的肝脏都有所变化,但雌性小鼠比雄性小鼠的肾脏更易受到损害.     

Determination of the Movements of Impacted Upper Canines by X-Ray Photogrammetric Methods

Samples of gold soldered assemblies from three different dental casting gold alloys were subjected to various homogenizing heat treatments. The distribution of available alloy components in the region of the gold-solder junction was investigated using electron-probe micro-analysis. An extensive statistical treatment of the data was performed. Concentration differences between casting alloy and solder alloy were not levelled out to any great extent unless after prolonged heat treatment (3 hours) for one of the three alloys. However, this heat treatment caused grain growth and an increased amount of microporosities in the region of the joint. In the soldered assemblies from two of the three casting alloys microphases with a composition different from the original alloys appeared at the gold-solder junction after heat treatment. The results show that homogenizing heat treatment of gold soldered assemblies should not be performed as a routine.     

内生型转铁蛋白-金纳米簇探针的合成及其对前列腺癌的靶向成像研究

目的 以转铁蛋白(transferrin,Tf)为模板,氯金酸为原料,原位合成靶向荧光探针-内生型转铁蛋白-金纳米簇(gold nanoclusters,AuNCs),并以前列腺癌(prostate cancer,PCa)为模型,探讨该荧光探针的靶向成像效果.方法 利用场发射透射电子显微镜及粒度分析仪分析所合成的荧光探针的形貌、水合粒径及分布;利用紫外-可见分光光度计及荧光分光光度计对其光学性能进行表征;MTT法检测细胞毒性;并通过细胞荧光成像及竞争抑制实验表征其肿瘤的特异性靶向效果;静脉注射Tf-AuNCs至PC-3种植瘤鼠体内,进行连续荧光成像,评价其肿瘤靶向成像效果;通过组织病理学明确其活体毒性.结果 本研究制备的Tf-AuNCs粒径约为3 nm,荧光发射峰为700 nm,保留了Tf及金纳米簇的性能;细胞成像结果显示Tf-AuNCs对前列腺肿瘤细胞(PC-3)特异性靶向效果好;小动物活体成像结果显示Tf-AuNCs探针仅需15 min即可准确显示肿瘤部位,至2h时肿瘤区荧光强度达峰值,表明其具有良好的活体肿瘤成像能力;病理学结果表明Tf-AuNCs具有良好的生物相容性.结论 Tf-AuNCs荧光探针具有良好的光学性能、特异靶向能力,并具有优异的荧光成像能力及良好的生物相容性,将有望应用于PCa的早期影像学分析.     

Assessment of oxidative stress induced by gold nanorods following intra-tracheal instillation in rats

Gold nanorods (GNRs) are used for their wide variety of applications in various industries. There is a little availability of data related to toxicity and ecological implications of these GNRs. The study evaluated the oxidative stress induction following intra-tracheal instillation of 1 and 5?mg/kg b.w. doses of 10 and 25?nm GNRs by estimating various oxidative stress markers including lipid peroxidation (malondialdehyde; MDA), glutathione (GSH), superoxide dismutase (SOD), catalase and total antioxidant capacity (TAC) after 1?day, 1?week, 1?month, and 3?months post exposure periods. The results have shown increased MDA levels and decreased GSH levels following 1?day and 1?week post exposure periods, indicating induction of oxidative stress. Also, the SOD, catalase and TAC levels were significantly decreased following exposure of both 10 and 25?nm GNRs after 1?day and 1?week after exposures, indicating the inhibition of antioxidant defense mechanisms. Moreover, the 10?nm GNRs at 5?mg/kg dose displayed greater changes in all the estimated parameters, representing dose and size based induction of oxidative stress by GNRs. In contrast, a little change was observed during 1?month and 3?months post exposure periods, may be due to recovery. Finally, the GNRs induced dose-size-dependent oxidative stress induction by various oxidative stress markers following intra-tracheal instillation in rats.