简介:AbstractBackground:Pharmacological factors used to induce insulin resistance (IR) in in vitro models may not mimic the full in vivo features of type 2 diabetes mellitus (T2DM). This study aimed to examine the ability of diabetic serum (DS) to induce IR and investigate whether adipose-derived mesenchymal stem cell conditioned medium (ADMSC-CM) reverses DS-induced IR.Methods:DS was obtained from newly diagnosed T2DM patients. IR was induced in differentiated 3T3-L1 cells by employing dexamethasone, tumor necrosis factor alpha (TNF-α), palmitate and DS. Glucose uptake (2-[N-[7-nitrobenz-2-oxa-1,3-diazol-4-yl] amino]-2-deoxyglucose(2-NBDG) uptake assay), intracellular levels of reactive oxygen species (ROS), and superoxide radicals (O2-) (fluorescence microscopy and fluorometry) were analyzed in control and experimental samples. mRNA expression of key genes involved in glucose transport and inflammation were analyzed by using reverse transcription polymerase chain reaction (RT-PCR). Pro-inflammatory cytokines and phospho-insulin receptor substrate (IRS) (Ser-307) protein expression were analyzed by fluorescence activated cell sorter analysis. Statistical significance was determined by using one-way ANOVA followed by Tukey's multiple comparison tests.Results:ADMSC-CM significantly increased the DS-mediated decrease in 2-NBDG uptake (11.01 ± 0.50 vs. 7.20 ± 0.30, P < 0.01) and reduced DS-driven ROS (fluorescence count, 6.35 ± 0.46 vs. 9.80 ± 0.10, P < 0.01) and O2- (fluorescence count, 3.00 ± 0.10 vs. 4.60 ± 0.09, P < 0.01) production. Further, the ADMSC-CM restored DS-induced down regulation GLUT4 (1.52- fold, P < 0.05) as well as the up-regulation of PPARγ (0.35-fold, P < 0.01), and IKKβ (0.37-fold, P < 0.01) mRNA, and phospho-IRS (Ser-307) protein expression compared to the baseline (median fluorescence intensity, 88,192 ± 2720 vs. 65,450 ± 3111, P < 0.01). DS induced IR, similar to the traditionally used pharmacological factors, namely dexamethasone, TNF-α, and palmitate, which can be attributed to the significantly higher pro-inflammatory cytokines levels (TNF-α (2.28 ± 0.03 pg/mL vs. 2.38 ± 0.03 pg/mL, P < 0.01), interleukin 6 (IL)-6 (1.94 ± 0.02 pg/mL vs. 2.17 ± 0.04 pg/mL, P < 0.01), IL-17 (2.16 ± 0.02 pg/mL vs. 2.22 ± 0.002 pg/mL, P < 0.05), and interferon gamma (IFN-γ) (2.07 ± 0.02 pg/mL vs. 2.15 ± 0.04 pg/mL, P < 0.05)) in DS.Conclusions:DS can be explored as a novel inducer of IR in in vitro studies with further standardization, substituting the conventionally used pharmacological factors. Our findings also affirm the validity of ADMSC-CM as a prospective insulin sensitizer for T2DM therapy.
简介:摘 要:本文通过平板试验件研究了相同孔径下扩张型、收缩型及直孔的流量系数的差异,并通过数值模拟分析三种类型气膜孔流量系数差异的原因.研究结果表明:不同孔型的气膜孔流量系数差异较大,主要受气膜孔有效流通面积的影响;在节流孔径相同的条件下,收缩型孔的流量系数最大,扩张型孔和直孔的流量系数相当.
简介:摘要:职业教育最近的“职教20条”方案中,不仅强调了“职业教育与普通教育是两种不同的教育类型,具有同等重要地位”,还侧重描述了职业教育教学改革的方向是“促进产教融合校企“双元”育人”。全国各大中专院校围绕这个方向开展了如火如荼的课程改革,各个中专专业的就业导向性很符合校企合作的要求,所以课程改革比较容易实现,但是3+3专业有其特殊性就是一个难题,现在以电子技术专业基础课程为例,分析一下产教融合背景下的课程改革,以新型学徒制为课程改革的方式,教师认真研究开发新课程。
简介:摘要:砌体结构作为最古老的建筑形式之一,在现有的工业、民用及古建筑中占有较大比重。组成砌体结构的砖、石、砂浆属于脆性材料,其抗压强度较高,抗拉、抗剪性能较差。一些现存的砌体结构是在相关设计理论和抗震规范建立之前设计和建造的,属于无筋砌体结构,不符合抗震规范要求,抗震性能较差,在地震作用下,无筋砌体结构由于刚度、强度和耗能能力的快速退化会产生突然脆性破坏,在历次地震中损伤较为严重。为了提高无筋砌体结构的抗震性能,外包型钢加固法、钢筋网水泥砂浆面层加固法、钢筋混凝土面层加固法、外加预应力撑杆加固法、增设砌体扶壁柱加固法等传统的加固方法被应用于砌体结构加固,但是这些方法都在不同程度上改变了原建筑的外观和尺寸,增加了结构的重量。纤维增强复合材料(fiberreinforcedpolymer,简称FRP)由于具有轻质、高强、加固增厚量低、耐腐蚀、耐疲劳、施工方便等优势,已被广泛应用于砌体结构加固领域。
简介:摘要:随着人均汽车保有量的大幅提高,在需求增加、资源有限的情况下,汽车轻量化尤为重要。汽车轻量化的优点是减少环境污染,保护道路,减少汽车零部件之间的磨损,间接增加使用年限,进一步减少环境污染。为了解决上述技术问题,优化产品结构,使用纤维增强复合材料,改善工艺参数。根据效果和资金投入程度,通常使用优化的产品结构分析汽车产品。碳纤维增强复合材料热膨胀系数小,密度低,具有高强度和系数、高温、抗疲劳等其他材料无法比拟的新材料。最高的单一直径只有7微米,是高级工业产品的首选材料。通过优化产品结构和新材料的结合,可以获得最佳性价比。随着国内先进技术的迅速发展,对新材料的优化吸引了很多有希望的人。