2型糖尿病风险预测模型性能比较研究

目的:探讨5种常见机器学习算法在2型糖尿病风险预测模型构建中的预测性能差异与应用价值。方法:利用Pima Indians等公共糖尿病数据集,对Logistic回归(LR)、支持向量机(SVM)、决策树(DT)、朴素贝叶斯(NB)和k最近邻域法(KNN)5种常见算法分别建模,设置不同训练集比例和随机重复抽样,以准确性、稳定性作为主要评判标准对不同模型进行比较研究。结果:对于所有模型,训练集比例在0.8~0.85时预测效果最佳,并且能够容忍一定的缺失值,训练集的随机抽样也会影响预测效果,不同预测模型的预测效果存在明显区别,LR、SVM和NB方法预测效果较好。结论:LR方法整体效果最好,研究结果可为临床2型糖尿病预测模型评估和核心算法的选择提供参考。

Protective Effects and Potential Mechanism of Tongxinluo on Mice with Thromboangiitis Obliterans Induced by Sodium Laurate

Objective To investigate the effects of Tongxinluo(TXL)on thromboangiitis obliterans(TAO)and the underlying mechanisms.Methods Ninety male C57/BL6J mice were randomly divided into 6 groups according to a random number table:the sham group,TAO model group,Compound Danshen Tablet(CDT)group,and the high-,medium-,and low-dose TXL groups.All mice except the sham group were injected with sodium laurate(0.1 mL,5 mg/mL)in the femoral artery to establish TAO mouse model.After modeling,mice in the sham and TAO model groups were intragastrically administered 0.5%(w/v)sodium carboxymethylcellulose,mice in the CDT group were intragastrically administered 0.52 g/kg CDT,and mice in the TXL-H,TXL-M,and TXL-L groups were intragastrically administered 1.5,0.75,and 0.38 g/kg TXL,respectively.After 4 weeks of gavage,the recovery of blood flow in the lower limbs of mice was detected by Laser Doppler Imaging.The pathological changes and thrombosis of the femoral artery were observed by morphological examination.The expressions of tumor necrosis factorα(TNF-α)and inducible nitric oxide synthase(iNOS)in the femoral artery wall were detected by HE staining.Levels of thromboxane B2(TXB2),6-keto-prostaglandin F1α(6-keto-PGF1α),endothelin-1(ET-1),interleukin(IL)-1βand IL-6 were measured using enzyme-linked immunosorbent assay(ELISA).Levels of activated partial thromboplastin time(APTT),prothrombin time(PT),thrombin time(TT)and fibrinogen(FIB)were detected by a fully automated biochemical analyzer.Results TXL promoted the restoration of blood flow in the lower limbs,reduced the area of thrombosis in the femoral artery,and alleviated the pathological changes in the femoral artery wall.Moreover,the levels of TXB2,ET-1,IL-6,IL-1β,TNF-αand iNOS were significantly lower in the TXL groups compared with the model group(P<0.05 or P<0.01),while the level of 6-keto-PGF1αwas significantly higher(P<0.01).In addition,APTT,PT,and TT were significantly prolonged in TXL groups compared with the model group(P<0.05 or P<0.01),and FIB levels were significantly decreased compared with the model group(P<0.01).Conclusions TXL had a protective effect on TAO mice,and the mechanism may involve inhibition of thrombosis and inflammatory responses.TXL may be a potential drug for the treatment of TAO.

鄂尔多斯盆地延安气田山西组致密砂岩储层天然气充注模拟实验及含气性变化规律

致密砂岩气是当前非常规油气勘探开发的重点。为了弄清不同类型致密砂岩储层中天然气的充注特征和含气性变化规律,选取鄂尔多斯盆地延安气田山西组12个砂岩样品,依据岩性、物性和孔隙类型将其划分为3类,并分别开展了不同渗透率、不同充注流速和不同充注压差下的天然气充注模拟实验。结果表明,物性较好致密砂岩的中孔隙对含气饱和度的贡献大于小孔隙,而超低孔渗致密砂岩的小孔隙对含气饱和度的贡献大于中孔隙。临界注入压力是岩石的固有属性,不随流速的变化而变化,含气饱和度与流速成正比关系,流速越快,含气饱和度越高。充注压差越大,气体突破时间越短,含气饱和度就越高,随着充注时间增加,含气饱和度变化很小,最终趋于某一恒定值,即岩心束缚水状态下的含气饱和度。该研究能够为延安气田致密砂岩储层的物性下限分析和运移机理探讨提供实验基础和理论依据。