Experimental Study on the Mechanical Properties and Compression Size Effect of Recycled Aggregate Concrete

To explore the basic mechanical properties and size effects of recycled aggregate concrete (RAC) with different substitution ratios of coarse recycled concrete aggregates (CRCAs) to replace natural coarse aggregates (NCA), the failure modes and mechanical parameters of RAC under different loading conditions including compression, splitting tensile resistance and direct shear were compared and analyzed. The conclusions drawn are as follows: the failure mechanisms of concrete with different substitution ratios of CRCAs are similar; with the increase in substitution ratio, the peak compressive stress and peak tensile stress of RAC decrease gradually, the splitting limit displacement decreases, and the splitting tensile modulus slightly increases; with the increase in the concrete cube’s side length, the peak compressive stress of RAC declines gradually, but the integrity after compression is gradually improved; and the increase in the substitution ratio of the recycled aggregate reduces the impact of the size effect on the peak compressive stress of RAC. Furthermore, an influence equation of the coupling effect of the substitution ratio and size effect on the peak compressive stress of RAC was quantitatively established. The research results are of great significance for the engineering application of RAC and the strength selection of RAC structure design.     

三种固定器械置入固定胫骨骨折的生物力学分析

背景:胫骨骨折后以胫骨骨折髓内钉、钢板内固定和外固定支架固定后骨折断端的轴向压缩、弯曲、扭转力将发生怎样的变化?目的:对比观察胫骨轴向控制髓内钉,胫骨接骨钢板及胫骨外固定支架3种内外固定器械置入固定胫骨骨折的生物力学特性.设计、时间及地点:观察性实验,于2007-08在吉林大学力学实验中心完成.材料:新鲜胫骨标本9对,由白求恩医科大学解剖教研室提供;夹具由吉林大学力学实验中心提供;胫骨轴向控制髓内钉为上海浦卫医疗器械厂产品;胫骨接骨板(钢板)为常州华森医疗器械有限公司产品;胫骨外固定支架为常州市康辉医疗器械有限公司产品.方法:9对新鲜尸体胫骨,随机分为髓内钉组,接骨板组和外固定支架组,每组3对.以线锯在胫骨中段锯开,制成DAT分类A1型骨折模型,分别以胫骨轴向控制髓内锁钉、钢板、外固定支架固定标本,在电子万能试验机上对3组标本进行轴向压缩实验和弯曲实验,在扭转试验机上进行扭转实验.主要观察指标:标本承受轴向压缩、弯曲载荷时的位移值和在转矩作用下扭转角度.结果:髓内钉组轴向压缩,弯曲位移小于接骨板组和外固定支架组,但差异无显著性意义(P > 0.05),髓内钉固定组扭转角度小于接骨板组和外固定支架组,差异有显著性意义(P < 0.05).结论:髓内钉内固定胫骨骨折组标本抗弯、抗扭、抗轴向压缩能力强,具有较好的力学特性.钢板固定组和外固定支架组抗弯和抗轴压缩能力也较强,虽抗扭转能力不如髓内钉组,但也具有较好的力学特性.     

PM2.5通过上调颗粒酶B促进IL-18表达加重肺部炎症

目的颗粒酶B促进组织炎症的作用日益引起重视,但其在PM_2.5导致的肺部炎症中是否发挥作用还不清楚,本文对在PM_2.5导致的肺部炎症中颗粒酶B的作用进行了研究。 方法第一步构建经气管滴注PM_2.5混悬液诱导大鼠肺部炎症的动物模型,实验分组为PBS组、PM_2.5(2 mg/kg)组、PM_2.5(6 mg/kg)组、PM_2.5(18 mg/kg)组。通过设置PM_2.5滴注剂量梯度,检测不同PM_2.5暴露剂量下大鼠肺组织颗粒酶B表达、病理和炎症评分,以探讨颗粒酶B表达水平与肺部炎症严重程度间有无相关性。第二步通过阻断颗粒酶B,探究在PM_2.5导致的肺部炎症中颗粒酶B是否发挥促进作用。第三步通过阻断IL-18,探究在PM_2.5导致的肺部炎症中颗粒酶B是否通过IL-18发挥作用。 结果随着PM_2.5滴注剂量升高,肺组织颗粒酶B表达增加,肺组织病理切片炎症细胞浸润和肺水肿程度加重,炎症评分增加,PM_2.5促进了肺组织颗粒酶B表达和肺部炎症;阻断颗粒酶B抑制了IL-18表达和NF-κB磷酸化,改善了PM_2.5导致的肺部炎症;阻断IL-18抑制了NF-κB磷酸化,改善了PM_2.5导致的肺部炎症。 结论PM_2.5通过上调颗粒酶B促进IL-18表达加重肺部炎症,其机制可能与激活NF-κB信号通路有关。     

减重手术对男性精子质量影响的Meta分析

目的系统评价减重手术对男性精子质量的影响。 方法计算机检索医学文献数据库,包括EMBASE、PubMed、Cochrane Library、万方、中国知网等,检索时间均从建库开始至2020年12月。搜集关于男性肥胖患者减重手术前后精子质量变化的文献,并对纳入文献进行质量评估,提取数据后采用Review Manager 5.3统计软件分析。 结果共纳入6项队列研究。Meta分析结果示：减重手术对男性肥胖患者射精量、精子浓度、运动精子（%）、向前运动精子（%）及正常形态精子（%）无明显影响,甚至可引起患者的精子总数下降（MD=43.29,95%CI: 3.24~83.34,P<0.03）。 结论减重手术不能改善精子质量,这需要更大样本及更长随访时间的随机前瞻性研究来证实。     

P波离散度预测扩张型心肌病伴阵发性心房颤动的临床价值

目的探讨P波离散度(Pd)预测扩张型心肌病(DCM)伴阵发性心房颤动(PAF)的价值。方法30例DCM伴阵发性Af者(A组),26例DCM无Af者(B组)。通过12导联体表心电图测定P波最大持续时间(Pmax)与最小持续时间(Pmin),计算Pd(Pd=Pmax-Pmin)。比较A组与B组的Pd与Pmax。结果A组Pd为48.44-13.8ms,Pmax为122.84-13.7ms,Pmin为76.2±12.0ms,与B组Pd30.6±10.2ms,Pmaxll0.2±10.4ms,Pmin80.8+11.5ms相比明显延长(p<0.01)。A组左房(LA)内径41.415.6mm,B组LA内径40.24-6.2mm,两组相比无显著差异(p>0.05)。为预测Af,取P波时限≥120ms,Pd≥40ms以及两者相结合,敏感性分别为86%、90%、73%,特异性分别为80%、85%、89%,阳性预测值分别为84%、87%、88%。结论Pd增加和P波宽度延长,可预测DCM并发阵发性Af的危险性。     

化疗药物配制方法探讨

为探讨化疗药物正确的配制方法，有效地预防化疗药物可能存在的职业危害，并使病人得到准确的用药剂量。提出配制化疗药物应在专门的化疗药物配制阃配制，使用特制的层流净化操作台，不具备条件者可在排风设备良好、空气流通的场所内配制。配制人员必须熟练掌握化疗药物的药理知识，配制时应严格做好查对工作。     

Pituitary adenomas in patients with multiple endocrine neoplasia type 1: a single-center experience in China

Purpose

To explore the clinical characteristics of pituitary adenomas in patients with MEN1 and to summarize treatment strategies for MEN1 in a Chinese population.

Methods

We retrospectively analyzed 54 MEN1 patients with pituitary adenomas diagnosed at Peking Union Medical College Hospital from March 2003 to January 2017. Clinical data, laboratory testing results, treatments of involved glands and treatment responses were collected and analyzed.

Results

The mean age at pituitary adenoma diagnosis was 53.9?±?17.8. The patients initially consulted the Endocrinology, General Surgery and Neurosurgery departments, in descending frequency. The nonfunctioning adenoma, prolactinoma, GH-secreting adenoma, cosecreting adenoma, and ACTH-secreting adenoma subtypes accounted for 48.1%, 27.8%, 9.3%, 9.3% and 5.6% of the cases, respectively. The remission rate for prolactinomas was 46.2% (6/13) treated with bromocriptine. And the remission rates were 87.5% (7/8) and 100% (3/3) for GH-secreting adenomas and ACTH-secreting adenomas respectively achieved by transsphenoidal surgery. Nineteen (35.2%) patients with asymptomatic nonfunctioning pituitary adenomas showed no progression after a 35-month follow-up with close observation. Regarding treatment priority, patients with thymic carcinoid tumors received first-line surgery, 54% of the patients with enteropancreatic tumors had these tumors treated first, and 26% of all patients had their pituitary adenomas treated first. In acromegalic patients, pituitary lesions tended to be treated first (75%, p?=?0.002). PHPT and adrenocortical adenomas can be managed with elective surgery.

Conclusions

The treatment of MEN1 requires cooperation between multidisciplinary teams. Individualized treatment according to the severity of glandular involvement is needed. GH-secreting and ACTH-secreting pituitary adenomas require active treatment, while nonfunctioning pituitary adenomas can be observed closely.

     

BMP4-mediated brown fat-like changes in white adipose tissue alter glucose and energy homeostasis

Expression of bone morphogenetic protein 4 (BMP4) in adipocytes of white adipose tissue (WAT) produces “white adipocytes” with characteristics of brown fat and leads to a reduction of adiposity and its metabolic complications. Although BMP4 is known to induce commitment of pluripotent stem cells to the adipocyte lineage by producing cells that possess the characteristics of preadipocytes, its effects on the mature white adipocyte phenotype and function were unknown. Forced expression of a BMP4 transgene in white adipocytes of mice gives rise to reduced WAT mass and white adipocyte size along with an increased number of a white adipocyte cell types with brown adipocyte characteristics comparable to those of beige or brite adipocytes. These changes correlate closely with increased energy expenditure, improved insulin sensitivity, and protection against diet-induced obesity and diabetes. Conversely, BMP4-deficient mice exhibit enlarged white adipocyte morphology and impaired insulin sensitivity. We identify peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC1α) as the target of BMP signaling required for these brown fat-like changes in WAT. This effect of BMP4 on WAT appears to extend to human adipose tissue, because the level of expression of BMP4 in WAT correlates inversely with body mass index. These findings provide a genetic and metabolic basis for BMP4’s role in altering insulin sensitivity by affecting WAT development.     

Sequence Heterogeneity of the ORF3 Gene of Porcine Epidemic Diarrhea Viruses Field Samples in Fujian,China, 2010–2012

Twenty-seven field samples that showed positive in PEDV detection were collected from different farms of Fujian province from 2010 to 2012. Their heterogeneity was investigated by analysis of the ORF3 gene because of its potential function as a representation of virulence. According to the results, six Fujian strains in Group 1 showed a different genotype with unique point mutations, which might be used in differentiation between PEDV groups and brought potential antigenic variation. P55 and five reference strains in Group 2 had a long length deletion, showing another genotype and might be involved in the variation of virulence. Phylogenetic analysis revealed that the collected Fujian strains were very distant from the vaccine development strain CV777, which might be the reason why the vaccine was inefficient to control the disease. The results can help to reconsider the strategy of PEDV vaccine management and prevent outbreaks of PEDV-induced diarrhea more efficiently.     

A serological scoring system to predict lymph node metastasis in patients with hepatocellular carcinoma

Background

Lymph node metastasis (LNM)has widely been recognized as a poor prognostic indicator for hepatocellular carcinoma (HCC) patients. Preoperative prediction of LNM is important for clinicians to decide on treatment. This study was designed to develop a simple and convenient system to predict LNM.