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1.
目的 研究成型工艺和结构设计对电子束选区熔化技术(SEBM)制备的菱形十二面体Ti6Al4V点阵材料相对密度、形貌和压缩性能的影响。方法 点阵的密度通过测定其尺寸和质量得出,采用电子万能试验机测试点阵结构的压缩性能,采用扫描电子显微镜观察点阵表面形貌。结果 SEBM成形Ti6Al4V支架的相对密度随着熔化功率增加和单胞尺寸减小而增大;以等离子旋转电极雾化技术制备的TC4粉末为原料成型的点阵结构具有优异的塑性,压缩应力—应变曲线平台区域波动小;TC4钛合金菱形十二面体多孔材料的密度与屈服强度和弹性模量的关系满足Gibson-Ashby方程,但指数分别为2.34和2.32。结论 通过调控点阵结构设计和SEBM成型工艺,可控制钛合金的孔隙率和压缩性能,满足骨科植入多孔材料需求。  相似文献   
2.
马林  刘小翠  邓斌 《中草药》2020,51(16):4259-4265
目的探讨小檗碱调节糖原代谢的机制及对糖原结构的影响。方法采用自发型糖尿病模型db/db小鼠作为疾病模型鼠,考察小檗碱对db/db小鼠血糖水平的影响;提取小鼠的肝糖原进行体积排阻色谱(SEC)和透射电镜(TEM)分析,考察小檗碱对db/db小鼠肝糖原的结构影响,并探讨其影响机制。结果小檗碱可以显著性降低db/db小鼠的空腹血糖,降低db/db小鼠血清胰岛素水平;改善db/db小鼠肝糖原的结构不稳定性;降低db/db小鼠肝组织中糖原磷酸化酶(GP)、糖原脱分支酶(GDBE)和环磷酸腺苷(cAMP)表达水平,降低血清胰高血糖素水平。结论小檗碱可以调控cAMP/GP信号通路,改善db/db小鼠的肝糖原结构,修复受损糖原结构,这可能是其调节肝糖代谢,改善糖尿病症状的机制之一。  相似文献   
3.
目的:研究临泉产穿心莲地上部分黄酮类化学成分。方法:利用硅胶、凝胶Sephadex LH-20、ODS柱色谱等方法,对临泉产穿心莲地上部分90%乙醇提取物的化学成分进行分离和纯化,运用波谱学技术对分离得到的单体化合物进行结构鉴定。结果:从穿心莲的乙醇提取物中分离并鉴定出14个黄酮类化合物,分别是双氢汉黄芩素(1)、5-羟基-6,7-二甲氧基黄酮(2)、2-羟基-3,4,6-三甲氧基查尔酮(3)、5-羟基-7,8-二甲氧基黄酮(4)、穿心莲素(5)、5-羟基-7,8,2',5'-四甲氧基黄酮(6)、5,7,8-三甲氧基二氢黄酮(7)、2'-甲氧基-5,6,7-三甲基黄芩素(8)、5,7,4'-三甲氧基黄酮(9)、高车前素(10)、7,8,2',5'-四甲氧基黄酮-5-O-β-D-吡喃葡萄糖苷(11)、穿心莲黄酮苷A(12)、穿心莲黄酮苷C(13)、穿心莲黄酮苷G(14)。结论:其中化合物1、2、3、8首次从穿心莲中分离得到。  相似文献   
4.
目的:利用简单序列重复区间扩增多态性(ISSR)分子标记技术对江西省锐尖山香圆进行亲缘关系和遗传结构分析,为该药材资源的保护和利用提供理论依据。方法:采集江西省4个县6个采样地的22份锐尖山香圆叶片样本,利用试剂盒法提取基因组DNA。利用64条通用ISSR分子标记引物进行聚合酶链式反应(PCR)扩增,运用聚丙烯酰胺凝胶电泳(PAGE)方法检测条带。选择NTsys 2. 10e软件,采用非加权配对算术平均法(UPGMA)计算遗传相似系数并聚类分析。利用Structure 2. 1软件分析群体遗传结构。结果:有48条ISSR引物扩增后获得了产物,多态性条带百分率处于45. 45%~100%。UPGMA聚类分析表明4个县的锐尖山香圆资源不能按照行政区域划分分别聚为一类,群体遗传结构分析表明22份锐尖山香圆群体可以划分为3个类群。结论:江西省锐尖山香圆群体间存在着基因交流,会影响该药材不同地理来源种质资源的遗传结构组成。  相似文献   
5.
Researchers continue to lament the lack of organisational focus in the sociology of health and illness. Although studies have increasingly focused on boundaries between organizations, little such research has focused on the formal boundaries within the hospital itself. Given its dramatic compartmentalisation, and continuing prevalence in health systems, the lack of organisational perspective in hospital research limits insights into the effects (as well as the construction) of the order of health work and care. With a greater emphasis on ‘ordering’ in the concept of negotiated order, the aim of this study is to examine the manifestation and consequences of the formal boundaries of hospital departments. Fieldwork featured 12 months of ethnography, including formal and informal observations, 80 audio‐recorded, semi‐structured interviews, and 56 field interviews, in the Emergency Departments (EDs) of two tertiary referral hospitals. Compared with in‐patient hospital departments, the ED has limited legitimacy claims of organ‐specific knowledge to transfer patients out of the ED. The manifestation of specialised knowledge hierarchies in organisational structures disadvantages patients who are older and who have chronic conditions, underpinning the argument that effects as well as the negotiation of stable organisational orders deserve increased attention in the sociology of health and illness.  相似文献   
6.
妇产科学是一门涉及面广、实践性和操作性均很强的学科,对医生临床操作能力的要求也格外严格。妇产科住院医师临床技能操作水平的高低是评价其岗位胜任力的重要指标,开展全面、规范的临床技能培训,有利于切实提高其临床操作能力,是培养合格妇产科专科医师的必经途径。研究以南京医科大学附属妇产医院为例,讲述了该院从目标体系、过程管理体系、考核评价体系和质量控制体系4个方面出发,探索构建适合专科医院特色的妇产科住院医师临床技能培训体系,并在实践过程中不断完善该体系,以期不断提升妇产科住院医师的临床工作能力,有效增强其岗位胜任力和综合素质。  相似文献   
7.
B cells are recognized as the main effector cells of humoral immunity which suppress tumor progression by secreting immunoglobulins, promoting T cell response, and killing cancer cells directly. Given these properties, their anti-tumor immune response in the tumor micro-environment (TME) is of great interest. Although T cell-related immune responses have become a therapeutic target with the introduction of immune checkpoint inhibitors, not all patients benefit from these treatments. B cell and B cell-related pathways (CCL19, −21/CCR7 axis and CXCL13/CXCR5 axis) play key roles in activating immune response through humoral immunity and local immune activation via tertiary lymphoid structure (TLS) formation. However they have some protumorigenic works in the TME. Thus, a better understanding of B cell and B cell-related pathways is necessary to develop effective cancer control. In this review, we summarize recent evidences regarding the roles of B cell and B cell-related pathways in the TME and immune response and discuss their potential roles for novel cancer treatment strategies.  相似文献   
8.
Intervertebral disc disease (IVDD) is a common musculoskeletal disease affecting about 5% of all individuals. It is characterized by lumbar disc herniation, which causes nerve root irritation, either mechanically or via inflammatory mediators, and results in radiating pain, known as sciatica. Numerous studies have been conducted to identify the causes and risk factors for IVDD. Lifting heavy loads, torsional stress, and motor vehicle driving are among the best-identified environmental risk factors. However, it has become evident recently from family and twin studies that genetic factors may also be important in IVDD. This hypothesis was strengthened by the identification of two collagen IX alleles associated with sciatica and lumbar disc herniation. In addition, disc degeneration has been shown to be related to an aggrecan gene polymorphism, a Vitamin D receptor and matrix metalloproteinase-3 gene alleles. This review highlights the genetic role and occupational aspects of IVDD.  相似文献   
9.
Objective: Studies have showed that different follow-up starting points might potentially impact the comparison between primary (PMIBC) and secondary muscle-invasive bladder cancer (SMIBC), but the only previous meta-analysis did not differentiate the follow-up starting points of included studies. With more trials published, we aim to update the meta-analysis comparing PMIBC and SMIBC.Methods: PubMed, Embase, Cochrane Library and ClinicalTrial.gov. systematically searched. Literatures comparing the survival outcomes of PMIBC and SMIBC were selected. Outcomes of cancer-specific mortality (CSM), overall mortality (OM) and recurrence-free survival (RFS) were pooled and grouped based on the starting point of follow-up (after initial diagnosis or radical cystectomy (RC)). Newcastle-Ottawa Scale (NOS) and funnel plot were employed to assess the study quality and publication bias, respectively.Results: A total of 17 high-quality studies were selected, with 5558 patients aged from 59.8 to 72.7 (mean value) involved. The male-to-female ratio was roughly 4:1 (4390/1124). SMIBC had lower risk of CSM after initial diagnosis (HR 0.81, 95%CI 0.67-0.98, P=0.03, I2=70%), but higher risk of CSM after RC (HR 1.45, 95%CI 1.27-1.65, P<0.00001, I2=64%). In terms of OM and recurrence, outcomes were pooled only after RC, which both turned out to be higher for SMIBC (OM: HR 1.50, 95%CI 1.30-1.73, P<0.00001, I2=0%; Recurrence: HR 1.66, 95%CI 1.36-2.02, P<0.00001, I2=48%). No obvious publication bias was observed from funnel plot.Conclusion: The current study suggested SMIBC had higher risk of CSM, OM and recurrence after RC, but lower risk of CSM after initial diagnosis.  相似文献   
10.
With the increasing demand for energy exchangers in underwater acoustic equipment, a modified 1-3 piezoelectric composite material is fabricated based on three-component phases. The new material outperforms the traditional two-phase 1-3 structure. Flexible silicone rubber polymer strengthened the piezoelectric composite and the properties of modified 1-3 piezoelectric composite have been tested by method of finite element simulation and experiment, respectively. This modified material has a high electromechanical coupling coefficient; the maximum can reach 0.684 and −3 dB bandwidth is superior to the two-phase 1-3 type. At the same time, the modified phase 1-3 type structure has an excellent decoupling effect. Silicone rubber can reduce the negative coupling vibration of epoxy resin, the vibration model simplification of piezoelectric composite, and the result of the experiment and simulation has good consistency.  相似文献   
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