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Evaluation the mechanical Properties of Nanofilled Composite Resin Restorative material

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Journal of Biomaterials and Nanobiotechnology 2012年第2期3卷 238-242页

作者： Ibrahim m. Hamouda Hagag Abd Elkader Dental Biomaterials Faculty of Dentistry Mansoura and Umm Al Qura Universities Egypt.

This study was designed to evaluate the wear resistance, fracture toughness and flexural strength of a nanofilled composite resin restorative material in comparison with a conventional hybrid composite resin. A total of 60 specimens were prepared from both types composite resins. Specimens were cured with a light curing device according to the manufacturer’s instructions. Wear resistance was evaluated through subjecting the specimens to wear testing at 0.1 bar.wet pressure against carbide abrasive counter-body using wear testing machine under water as lubricant. The test conditions were;speed = 265 rpm, load = 0.1 bar. time = 5 min. Flexural strength and fracture toughness were tested using three-point bending test in universal testing machine at a cross head speed of 2 mm/min until failure occurred. The nanofilled composite resin material exhibited higher wear resistance than the hybrid composite resin material. On the other hand, there were no significant differences between the two materials in values of flexural strength and fracture toughness. It was concluded that the nanofilled composite resin was harder but it does not stronger than the conventional hybrid composite resin.

关键词： Nanofilled Wear Flexural Strength Toughness Composite Resin

Laparoendoscopic Single Site Donor Nephrectomy: The Preliminary Experience

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Open Journal of Organ Transplant Surgery 2012年第4期2卷 52-55页

作者： Santosh A. Olakkengil m. mohan Rao Department of Surgery/Renal Transplantation Unit The Queen Elizabeth Hospital Woodville 5011Australia

methods: In our endeavour to give patients visibly scarless surgery we have raised the bar.to the next level in laparoscopic donor nephrectomy. We have moved from standard laparoscopy to LESS Laparoendoscopic single site donor nephrectomy. 1997 we introduced laparoscopic donor nephrectomy in Australia. In September 2008 we did our first LESS donor nephrectomy. September 2008 to October 2009, 6 laparoscopic donor nephrectomies were performed using a single port. Two types of devices have been used R-port and SILSTm Port. The device was inserted through an intra umbilical incision using open technique. Surgical technique was similar to the laparoscopic method and standard rigid and roticulator laparoscopic instruments were used. Results: All were completed with no major complications. In 3 an additional 5mm port was added to reduce the dissection time. Average operating time was 4.4 hours, warm ischemia time was an average of 7.16 minutes and post surgery hospital stay was an average of 1.41 days. All grafts functioned immediately after transplantation. Conclusion: Initial experience with this technique is promising. It is too early to draw any conclusions on its benefits to the donor in terms of reduced morbidity. However the donors appreciated the cosmesis. It is yet another learning curve for the transplant surgeon.

关键词： LESS Donor Nephrectomy

Analytical Study of mechanism of Concrete Cracking and Its Propagation Due to Corrosion of Reinforcement in RCC

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Open Journal of Civil Engineering 2016年第2期6卷 286-294页

作者： A. m. Jadhav H. K. munot m. Tech Structure College of Engineering Pune Pune India Department of Civil Engineering College of Engineering Pune Pune India

The experimental results which were carried out by different researchers on corrosion of RCC beam were validated in ABAQUS. A finite element (FE) model similar to experimental condition was generated in ABAQUS. The model with different percentages of corrosion and with varying load conditions was also generated. The deflections of RCC beam for different corrosion percentages and for varying load conditions were then validated. The model is then used to explore the effects of bar.radial expansion, due to formation of corrosion products, on the cracking of cover concrete. The predictions are compared with tests results from reinforced concrete accelerated corrosion specimens. The aim of the analytical investigation was to reveal the mechanism for the development of concrete cracking due to corrosion of reinforcement. Further the finite element model will be used to explain qualitatively the experimentally determined relationship between amount of corrosion for concrete cracking and ratio of concrete cover to bar.diameter, as well as that between reinforcement bond strength and amount of corrosion.

关键词： Corrosion of Reinforcement Cracking of Concrete Finite Element ABAQUS

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切向流酶膜反应器制备乳清蛋白抗氧化活性肽

切向流酶膜反应器制备乳清蛋白抗氧化活性肽

作者： Kamau S.m. 江南大学

学位级别：硕士

本文研究了酶和水解条件对乳清蛋白水解度和水解物DPPH自由基清除率的影响。采用胰蛋白酶,复合蛋白酶,风味蛋白酶,中性蛋白酶以及商业粗酶,碱性蛋白酶2709和中性蛋白酶AS 1398,在它们的最适水解pH和温度下水解乳清蛋白4h。所有酶水解得... 详细信息

本文研究了酶和水解条件对乳清蛋白水解度和水解物DPPH自由基清除率的影响。采用胰蛋白酶,复合蛋白酶,风味蛋白酶,中性蛋白酶以及商业粗酶,碱性蛋白酶2709和中性蛋白酶AS 1398,在它们的最适水解pH和温度下水解乳清蛋白4h。所有酶水解得到的乳清蛋白水解物都具有抗氧化活性。风味蛋白酶和AS 1398中性酶得到的水解物的DPPH自由基清除率最高,2709碱性蛋白酶具有最高的水解度。和其他酶乳清蛋白水解物相比,胰蛋白酶水解物具有稳定的溶解性,所以被用于研究其他的水解条件的影响作用。研究表明：温度,pH值,底物浓度和酶浓度影响乳清蛋白胰蛋白酶水解物的水解度和DPPH自由基清除能力。采用胰蛋白酶水解底物浓度40 mg／mL的乳清蛋白1h,采用响应面回归分析得到最佳水解工艺为：温度40.12℃、酶底物比6%(w/w)、pH7.02。采用二次和线性模型方程分析水解度和DPPH自由基清除率,结果表明：温度和pH值对水解度和DPPH自由基清除率具有显著影响,pH值的影响尤为显著。在最佳酶解条件下得到的乳清蛋白胰蛋白酶水解物的水解度为22.90±0.12％。DPPH自由基,超氧阴离子自由基和羟基自由基清除率的IC50分别为4.1,3.7,mg／mL,水解物的浓度为10.00 mg／mL时,还原力为0.886±0.010。乳清蛋白胰蛋白酶水解物主要由分子量小于1000 Da的短肽和氨基酸组成。与肽的抗氧化性质相关的疏水性氨基酸含量为水解物氨基酸总含量的39.01%。采用10 kDa的超滤切向流的酶膜反应器,流速的范围为10-60 mL／min,初始水通量和截留再循环流速的范围为55-160mL／min,采用渗透总量,产物的抗氧化活性,平均膜通量和最终压力来评价酶膜反应器的稳定性。在低水通量10mLs/min时,较高的再循环流速会有高的平均膜通量,值为52%,而较低的再循环流速下,膜平均通量为29%.,当初始水通量升高至60 mL／min时,降低再循环流速,平均膜通量从13.07%降到11.33%。渗透总量随着再循环速率的提高而增加,再循环流速为160 mLs／min时,渗透总量为579 mLs,但是此时的DPPH自由基清除率为64.02±0.19%,低于130mLs/min时的65.40±0.38%。在高再循环流速下,截留组分的DPPH自由基清除率高于透过组分。不考虑初始水通量,在低再循环流速下,渗透组分的DPPH自由基清除率达到71.37±0.98%,高于高再循环流速下得到的渗透组分的DPPH自由基清除率59.64±0.71。比较最终压力,结果表明,初始水通量不变时,高再循环速率导致高的操作压力>1.5 bar.。采用box-behnken因子设计优化酶膜反应的条件,该设计中包含影响酶膜反应的因素的三个水平。分别是水解初始的温度(40,45,和50℃),酶浓度(1,2,和3%)和初始水流通(15,20,和25 mLs／min)。指标包括总含量(g),蛋白转化率,透过组分的抗氧化活性,以及最终的操作压力(bar.和平均膜通量。控制底物浓度为40 mg／mL,pH 7.0,水解时间为2h。采用10 kDa(聚醚砜)的膜。涉及到六个变量的优化模型的分析研究表明：当最终压力为0.75 bar.时,DPPH自由基清除率和总量达到最大,此时,Ti 50℃,,ES 2％, Ji15。DPPH自由基清除率,冻干后水解物的总量和最终的压力值分别为62.56±0.40%,14.78±1.07 g和0.91±0.01 bar.。其他的结果为：渗透部分的蛋白含量为83.93±0.27%,透过部分的浓度为22.30±1.20mg/mL。平均膜通量为36.79±0.88%,水解度为18.06±0.15%。采用二级超滤浓缩分离从酶膜反应(10 kDa)得到的酶解物。采用3 kDa和1 kDa的切向流膜分离酶解物以期减小颗粒粒径。收集冻干10-3 kDa组分(3 kDa截留组分),3-1 kDa组分(1 kDa截留组分),和>1 kDa(1 kDa透过组分)。酶解物的相对分子量分布范围在130 Da～10000 Da。所有的组分都具有抗氧化活性并且有浓度依赖性。酶膜反应中得到的水解物的IC50值分别为：DPPH·,7.85;O2-·,3.25;·OHmg／mL,10-3 kDa组分的IC50值分别为DPPH·,6.49;O2-·,3.60;·OHmg／mL。酶膜反应得到的水解物和10-3 kDa组分富含必需氨基酸和高组分的疏水性氨基酸。二级超滤分离降低了浓缩物的必需氨基酸和疏水性氨基酸的含量。酶膜反应器和二级超滤分离联用是制备具有抗氧化活性的乳清蛋白肽的有效方法。分别研究分批反应,酶膜反应以及酶膜反应与超滤浓缩联用得到的水解物的对热,p

关键词：乳清浓缩蛋白抗氧化活性酶膜反应切向流自由基清除率

去除局部破损混凝土后钢筋混凝土梁受弯性能理论分析

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工业建筑 2003年第4期33卷 49-52页

作者：李文张素梅 m.Raoof 大庆石油学院建筑工程系安达151400 哈尔滨工业大学土木工程学院哈尔滨150090 Loughborough University of Technology

在钢筋混凝土梁修复加固的过程中 ,常常可能去除梁上部分破损的混凝土 ,使钢筋外露 ,在荷载作用下 ,造成梁的力学性能发生变化。基于对钢筋混凝土梁变形分析 ,利用数值分析方法 ,详细讨论了在忽略梁剪切变形的条件下 ,去除局部破损混凝... 详细信息

在钢筋混凝土梁修复加固的过程中 ,常常可能去除梁上部分破损的混凝土 ,使钢筋外露 ,在荷载作用下 ,造成梁的力学性能发生变化。基于对钢筋混凝土梁变形分析 ,利用数值分析方法 ,详细讨论了在忽略梁剪切变形的条件下 ,去除局部破损混凝土、受拉钢筋暴露的钢筋混凝土梁的理论分析方法。给出了计算去除局部破损混凝土、部分受拉钢筋暴露的钢筋混凝土简支梁挠度和承载力的具体分析步骤和计算公式 ,计算结果和试验结果吻合良好。

关键词：钢筋混凝土梁受弯性能修复承载力挠度力学性能

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山羊胚胎体外培养条件的优化

中国畜牧兽医 2010年第4期37卷 146-149页

作者：刘羿羿赵高平李燕白俊王申元巴特尔周欢敏内蒙古农业大学生物工程学院呼和浩特010018 内蒙古农业大学动物科学学院呼和浩特010018 内蒙古大学哺乳动物生殖生物学及生物技术教育部重点实验室呼和浩特010021 内蒙古农业大学科技处呼和浩特010018

为优化山羊胚胎体外培养条件,本试验比较了含有3种不同来源血清(优质胎牛血清、发情山羊血清、前列腺素(PG)处理后发情山羊血清)的m199对卵母细胞成熟效果的影响,成熟率分别为65.95%、49.2%、76.47%,差异极显著(P0.05),改进的DmEm/F12... 详细信息

为优化山羊胚胎体外培养条件,本试验比较了含有3种不同来源血清(优质胎牛血清、发情山羊血清、前列腺素(PG)处理后发情山羊血清)的m199对卵母细胞成熟效果的影响,成熟率分别为65.95%、49.2%、76.47%,差异极显著(PmEm/F12发育体系培养受精卵,结果发现,SOFaa、CR1aa+输卵管上皮细胞的发育培养系统得到的囊胚率为29.62%、24.73%,差异不显著(P>0.05),改进的DmEm/F12发育液囊胚率最高为48.42%,差异极显著(P<0.01)。

关键词：发情山羊血清囊胚率输卵管上皮细胞

产前暴露于倍他米松与地塞米松的低体重新生儿近期不良结局的比较

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世界核心医学期刊文摘（妇产科学分册） 2005年第9期1卷 44-44页

作者： bar.Lev m.R.R. maayan-metzger A. matok I. J. Kuint 王伟华 Department of Neonatology Sheba Medical Center 52621 Ramat Gan Israel Dr.

OBJECTIVE: To assess the incidence of short-term outcomes of low birth weig ht infants (≤1,750 g) exposed prenattally to either dexamethasone or betamethaso ne. mETHODS: We retrospectively analyzed a cohort comprising 550 infants who wer e born alive at our center during the period January 1999 through December 2001, who weighed 1,750 g or less at birth, and who were exposed to prenatal steroid treatment. We compared brain ultrasound findings, such as intraventricular hemor rhage and cystic periventricular leukomalacia (PVL), as well as other clinical f indings, including respiratory distress syndrome (RDS), necrotizing enterocoliti s, retinopathy of prematurity, and bronchopulmonary dysplasia, for all premature infants whose mothers received either dexamethasone (from January 1, 1999 to Ju ne 30, 2000, n = 263) or beta-methasone (July 1, 2000 to December 31, 2001, n = 287). RESULTS: Patient characteristics (mothers and infants) were the same in b oth groups, with the exception of the number of steroid courses administered, th e number of women with premature rupture of membranes (defined as >24 hours), an d the number of women who had received tocolysis. No significant difference was found between the 2 groups with respect to intraventricular hemorrhage and cysti c PVL frequencies. No significant differences were found in the incidence of sho rt-term outcomes examined, despite the fact that the dexamethasone group was ex posed to a statistically significantly greater number of courses than the betame thasone group. CONCLUSION: There seem to be no advantages to maternal antenatal treatment with betamethasone compared with dexamethasone in reducing the risk of PVL in low birth weight (≤1,750 g) infants. Both drugs have the same effect on all short-term outcome parameters checked.

关键词：倍他米松呼吸窘迫综合征类固醇治疗视网膜病变胎膜早破无显著性差异保胎治疗超声结果发育不良日至

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基于空间矢量的点坝砂体储层构型建模

石油学报 2013年第1期34卷 133-139页

作者：李宇鹏吴胜和耿丽慧 mehran m.Hasanpour 印森林陈玉琨中国石油大学地球科学学院北京102249 University of Alberta

提出了一种基于空间矢量的曲流河点坝砂体构型建模方法。传统基于目标的方法是在建模的初始阶段定义网格,而基于空间矢量的储层构型建模方法直接在研究区内投放空间矢量定义的构型要素。该方法借鉴了计算机图像学中矢量图形存储的思路,... 详细信息

提出了一种基于空间矢量的曲流河点坝砂体构型建模方法。传统基于目标的方法是在建模的初始阶段定义网格,而基于空间矢量的储层构型建模方法直接在研究区内投放空间矢量定义的构型要素。该方法借鉴了计算机图像学中矢量图形存储的思路,采用了基于实数集的点、线、面所限定的体来定义构型要素。由于在模拟阶段模型不定义网格,因此模型不受网格尺寸的限制,模型模拟结果可以刻画不同规模层次的构型要素。并且由于在模拟过程中只是对构型要素的空间位置和形态定义参数进行调节,与传统的基于目标的模拟相比,更易满足井的条件约束,模拟收敛速度更快。笔者以中国东部油田某区块点坝砂体构型建模为例,给出了本方法的基本原理和具体的建模流程。

关键词：储层构型随机模拟矢量存储目标模拟曲流河点坝侧积层

海洋环境混凝土结构耐久性原位监测原理和剩余寿命预报

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工程力学 2011年第A02期28卷 78-84,96页

作者：干伟忠金伟良 RAUPACH m 宁波工程学院混凝土结构耐久性研究所浙江宁波315016 浙江大学结构工程研究所浙江杭州310027 德国亚琛工业大学土木工程研究所北威州亚琛52062

该文介绍了海洋环境中混凝土结构耐久性原位监测研究与应用的新近进展。内容包括混凝土结构耐久性监测的概念、原理和作用,欧洲第一代混凝土结构耐久性预埋式梯形阳极和后置式无损监测传感单元及其系统,以及通过国际合作研究发展的基于... 详细信息

该文介绍了海洋环境中混凝土结构耐久性原位监测研究与应用的新近进展。内容包括混凝土结构耐久性监测的概念、原理和作用,欧洲第一代混凝土结构耐久性预埋式梯形阳极和后置式无损监测传感单元及其系统,以及通过国际合作研究发展的基于电化学原理和光纤辅助技术的第二代耐久性监测技术,尤其是结构各部位钢筋脱钝腐蚀的个性化判据捕获方法和作为后置作业前提的微创介入技术。工程实践表明:对混凝土结构中钢筋的腐蚀状态进行持续监测,是确保基础设施设计使用寿命的切实可行的耐久性设计措施;源自原位活体混凝土的耐久性综合信息可以用于结构剩余寿命的预测和预报。

关键词：海洋环境混凝土结构耐久性无损监测剩余寿命