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1.
IntroductionThe aim of this study was to investigate the influence of mass and the polar moment of inertia on the torsional behavior of nickel-titanium rotary instruments to understand which parameter of cross-sectional design had a key role in terms of torsional resistance.MethodsFour different instrument models were designed and meshed using computer-aided engineering software (SolidWorks; Dassault Systems, Waltham, MA). Instrument models shared the same characteristics, except for cross-sectional design; triangle, rectangle, square, and hollow square geometry was selected. Finite element analysis was performed simulating a static torsional test using the FEEPlus internal solver (Solid Works). Von Mises stress and torsional load at fracture were calculated by the software. Linear regression analysis was performed to investigate the relationship of the polar moment of inertia, cross-sectional area, inner core radius, and mass per volume on the torsional resistance of nickel-titanium rotary instruments.ResultsThe polar moment of inertia positively affected the maximum torsional load with the highest level of correlation (R2 = 0.917). It could be stated that the higher the polar moment of inertia is, the more maximum torsional load at fracture is present. Mass and cross-sectional area had a lower level of correlation compared with the polar moment of inertia (R2 = 0.5533). According to this, 2 instruments with the same mass/mm and/or cross-sectional area could have different torsional resistance.ConclusionsThe polar moment of inertia can be considered as the most important cross-sectional factor in determining the torsional resistance of rotary instruments over metal mass and cross-sectional area.  相似文献   
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目的研究并比较不同规格怀牛膝不同极性部位的HPLC指纹图谱,探索其内部质量差异,为该药材的规格标准完善及临床用药提供参考。方法将怀牛膝用体积分数75%乙醇水浴回流提取,得体积分数75%乙醇回流提取物,用40 mL水溶解后,依次用石油醚、三氯甲烷、乙酸乙酯、正丁醇进行萃取,得到各萃取相及萃取后的水相,浓缩至浸膏,采集各部位HPLC指纹图谱;运用相似度、综合聚类法进行数据分析,同时对其不同部位的指纹图谱进行比对分析。结果石油醚、氯仿部位均标定了11个共有峰,乙酸乙酯部位标定了10个共有峰,正丁醇部位标定了19个共有峰,水部位标定8个共有峰;氯仿部位指纹图谱相似度差异较大,其他部位指纹图谱相似度差异较小,均在0.9以上;石油醚部位指纹图谱差异主要体现在峰高,乙酸乙酯部位、氯仿部位、水部位的化学成分种类及峰高均存在差异;综合聚类分析能将不同规格怀牛膝区分开。结论不同规格怀牛膝内部质量存在差异;实验中所建立的HPLC指纹图谱可以全面反映不同规格怀牛膝的化学成分分布,为不同规格怀牛膝的整体质量评价提供参考。  相似文献   
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目的:探讨极性蛋白Pard3在乳腺癌组织中的表达及与临床病理特征的相关性。方法:收集2017年6月至2019年12月我院外科行乳腺癌切除术的93例女性乳腺癌患者的乳腺癌组织、癌旁正常组织和临床资料。采用免疫组化技术检测Pard3在乳腺癌组织和癌旁正常组织中的表达情况,并结合临床资料,分析Pard3在乳腺癌组织中的表达量与患者临床病理特征之间的关系。采用二分类的Logistic回归分析进行Pard3在乳腺癌组织中的表达与患者临床病理特征相关性分析。结果:免疫组化结果显示,在乳腺癌组织中Pard3的表达水平明显下降。乳腺癌组织中阳性率为31.2%(29/93),显著低于癌旁正常组织中的阳性率72.0%(67/93),差异有统计学意义(P=0.000)。临床病理特征相关性分析结果显示Pard3的表达与患者年龄、肿瘤大小、病理类型、淋巴结转移情况之间的关系差异无统计学意义(P>0.05);与TNM分期、组织分化程度、ER、PR、HER-2、Ki-67表达之间的关系差异有统计学意义(P<0.05)。经Logistic回归分析结果显示,Pard3的表达与分化程度、ER表达呈正相关,与TNM分期呈负相关,与PR、HER-2、Ki-67表达无相关性。结论:极性蛋白Pard3在乳腺癌组织中的表达显著低于癌旁正常组织,其在乳腺癌组织中的表达量与组织分化程度、ER表达呈正相关,与TNM分期呈负相关。  相似文献   
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IntroductionType II AEG is now considered as oesophageal cancer in the seventh and eighth edition of TNM classification but optimal surgical approach for these tumors remains debated. The objective of the study is to assess and compare surgical and oncological outcomes of two surgical approaches: superior polar oesogastrectomy (SPO) or total gastrectomy (TG) in patients with type II adenocarcinoma of the oesophagogastric junction (AEG).Material and methods183 patients with type II AEG treated from 1997 to 2010 in 21 French centers by SPO or TG were included in a multicenter retrospective study. The surgical and oncological outcomes were compared between these two surgical approaches.ResultsA TG was performed in 64 (35%) patients whereas 119 (65%) patients were treated by SPO with transthoracic approach in 100 of them (83.2%) and transhiatal approach with cervicotomy in 19 (16.8%). Surgical outcomes were comparable between the two approaches with a postoperative mortality rate of 4.9% and a severe operative morbidity rate within 30 days of 15.3%. Median survival in patients operated on by TG was of 46 months compared to 27 months in patients treated by SPO (p = 0.118). At multivariate analysis, TG appears to be an independent good prognostic factor compared to SPO (HR = 1.847; p = 0.008). However, TG was also associated with a higher rate of incomplete resection, (12.5% vs 5.9%; p = 0.120).ConclusionWhen TG allows obtaining tumor-free resection margins, this approach should be preferred to SPO.  相似文献   
7.
C. Zhao  L. Zhou  J. Zhang  X. Ling 《Andrologia》2016,48(10):1138-1144
To explore the need for rescue intracytoplasmic sperm injection (ICSI) in cases of partial fertilisation failure during a conventional in vitro fertilisation cycle, rescue ICSI was performed for cycles with a fertilisation rate of <50%. The data were divided into three groups based on the fertilisation rate: group 1 (0%), group 2 (<25%) and group 3 (>25%). The impact of rescue ICSI on each group was then analysed in terms of ovum fertilisation, embryo development, embryo utilisation and selection of embryos for transfer. Rescue ICSI was performed on 1831 unfertilised oocytes from 313 cycles. The fertilisation rates for group 1, group 2 and group 3 were 74.66, 68.35 and 65.46%, and the rate of polyploidy in the three groups was 8.55, 11.33, and 14.47%. The percentage of embryos that can be transferred from rescue ICSI for group 2 was 38.33%, and this value was higher than those of the other two groups. It is concluded that rescue ICSI is not recommended for patients with an IVF rate of >25% as the procedure is associated with a greater risk and low returns. However, it is feasible to perform rescue ICSI for patients with IVF rates of <25%.  相似文献   
8.
文章介绍了一款自动化装置的结构设计基本方案,该装置可应用在基于图像的显微病理分析中,能够对体液样本进行离心处理,并在不移动样本的情况下直接降低转速,配合沿样本平台径向直线运动的物镜,对样本进行逐格扫描.为了避免离心运动过后转速降低使得样品恢复原始状态,本文还设计了一款特殊的样本容器.该设计中还提出了一种新型微调平机构解决方案,用以调节旋转平台基准面与聚光镜发出光线的垂直度.最后通过有限元仿真软件对该机构进行模态分析.  相似文献   
9.
The health effects of green tea are associated with catechins: (?)-epigallocatechin-3-O-gallate (EGCG), (?)-epigallocatechin, (?)-epicatechin-3-O-gallate, and (?)-epicatechin. An understanding of compound absorption, distribution, metabolism, excretion, and toxicity characteristics is essential for explaining its biological activities. Herein, absorption, distribution, metabolism, excretion, and toxicity properties of in vivo detected metabolites of green tea catechins (GTCs) have been analyzed in silico. The influence of metabolic transformations on absorption, distribution, metabolism, and excretion profiles of GTCs corresponds to the effects of size, charge, and lipophilicity, as already observed for other small molecules. Mutagenic, carcinogenic, or liver toxic effects were predicted only for a few metabolites. Similar to galloylated GTCs EGCG and (--)-epicatechin-3-O-gallate, the sulfo-conjugates were predicted to bind at the warfarin binding site. The low free plasma concentration of these derivatives may be consequential to their serum albumin binding. The activity cliff detected for methylated conjugates of EGCG indicates that GTCs' pro-oxidative activity in bound state comes primarily from free hydroxyl groups of the pyrogallol ring B.  相似文献   
10.
Shiga toxin-producing Escherichia coli (STEC) serotypes, particularly E. coli O157:H7, possess a variety of fimbrial and afimbrial adhesins which have emerged as important contributors to intestinal colonization. E. coli O157:H7 possesses two chromosomal operons encoding long polar fimbriae (Lpf), which have been found to influence adherence in vitro and colonization in vivo. In a recent Infection and Immunity paper, we further explored the role of Lpf in E. coli O157:H7 intestinal colonization by using the infant rabbit model of STEC infection. We found that an E. coli O157:H7 Lpf-deficient mutant was outcompeted in the rabbit intestine by its parental strain, which may suggest that Lpf contributes to colonization. In contrast, the Lpf-deficient mutant showed an increased adherence to cultured intestinal epithelial cells, and we discovered that this strain overexpressed curli fibers. In this addendum article, we provide a continued perspective on the predicted roles of Lpf and curli, both in vivo and in vitro.  相似文献   
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