ZrO_2粒子弥散强化Q345钢的制备、显微组织与力学性能（英文）

采用中频感应熔炼炉熔化钢液和喂丝法相结合的技术,将ZrO_2粒子与铁粉混合物的预制棒加入到Q345钢熔液中,制备不同ZrO_2粒子含量(0%、5%和1.2%,质量分数)的弥散强化Q345钢。通过光学显微镜(OM)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察铸态、正火态和淬火态弥散强化钢的显微组织和拉伸断口形貌,并分析ZrO_2粒子弥散强化Q345钢的强化机理和断裂机理。结果显示,ZrO_2粒子弥散强化Q345钢的强度得到显著提高;ZrO_2粒子附近形成的位错胞以及ZrO_2粒子的钉轧作用是弥散强化钢力学性能提高的主要强化机理;另外,硬质马氏体相、晶粒细化和高含量ZrO_2粒子在强化过程中均起到重要作用。采用纳米压痕仪对弥散强化钢的硬度和变形能力进行研究。结果表明,ZrO_2粒子弥散强化Q345钢的硬度随ZrO_2粒子含量的增加而提高。

Association between Self-reported Snoring and Prediabetes among Adults Aged 40 Years and Older without Diabetes

Background：Several previous studies have shown that snoring is associated with glucose metabolism and the development of diabetes,but rare study has shown the association between snoring frequency and prediabetes,particularly in China.We hypothesized that individuals who snore might have a higher risk of prediabetes.This study aimed to investigate the association between self-reported snoring and prediabetes in a Chinese population.Methods：A cross-sectional study was performed in three large communities of Beijing from December 2011 to August 2012 by recruiting individuals aged ≥40 years old.All participants were requested to complete a detailed questionnaire and undergo anthropometric measurements.A 75 g oral glucose tolerance test was performed in individuals without diabetes.Blood samples of all participants were collected;blood glucose and blood fat levels were measured.Multivariate logistic regression models were built to assess the association between snoring frequency and prediabetes.Results：A total of 13,592 participants （female：66.56%;mean age：56.8 ＆#177; 7.9 years;mean body mass index：25.5 ± 3.4 kg/m2） were included in the final analysis.Of these,30.9% were diagnosed with prediabetes,while 41.3% and 25.4% had occasional and habitual snoring,respectively.Habitual snoring was associated with an increased risk of prediabetes （odds ratio [OR]：1.3,95% confidence interval [CI]：1.1-1.4,P 〈 0.001）,after adjusting for diabetes and sleep-related confounders in the multivariable models.Habitual snoring was also associated with isolated impaired fasting glucose （IFG;OR：1.3,95% CI：1.0-1.6;P 〈 0.001） and isolated impaired glucose tolerance （IGT;OR：1.3,95% CI：1.2-1.5;P 〈 0.001）,but not IFG ＋ IGT （OR：1.1,95% CI：0.9-1.4;P =0.281）.When stratified by total cholesterol （TC） levels,this association between habitual snoring and prediabetes was observed only in individuals with TC 〈5.6 mmol/L （OR：1.4,95% CI：1.2-1.6;P〈 0.001）.Conclusions：Habitual snoring is associated with prediabetes,but only in individuals with TC 〈5.6 mmol/L.Further prospective studies are needed to confirm this finding.

Evaluation of Basal Serum Adrenocorticotropic Hormone and Cortisol Levels and Their Relationship with Nonalcoholic Fatty Liver Disease in Male Patients with Idiopathic Hypogonadotropic Hypogonadism

Background： Prolonged gonadal hormone deficiency in patients with idiopathic hypogonadotropic hypogonadism （IHH） may produce adverse effects on the endocrine homeostasis and metabolism. This study aimed to compare basal serum adrenocorticotropic hormone （ACTH） and cortisol levels between male IHH patients and healthy controls. Moreover, this study compared the basal hypothalamic-pituitary-adrenal （HPA） axis in patients with and without nonalcoholic fatty liver disease （NAFLD）, and also evaluated the relationship between basal HPA axis and NAFLD in male IHH patients. Methods： This was a retrospective case-control study involving 75 Chinese male IHH patients （mean age 21.4 ± 3.8 years, range 17 30 years） and 135 healthy controls after matching tbr gender and age. All subjects underwent physical examination and blood testing for serum testosterone, luteinizing hormone, follicle-stimulating hormone. ACTH, and cortisol and biochemical tests. Results： Higher basal serum ACTH levels （8.25 ±3.78 pmol/L vs. 6.97 ±2.81 pmol/L） and lower cortisol levels （366.70 ±142.48 nmol/L vs. 452.82 ± 141.53 nmol/L） were observed ill male IHH patients than healthy subjects （all P 〈 0.05）. IHH patients also showed higher metabolism parameters and higher prevalence rate of NAFLD （34.9% vs. 4.4%） than the controls （all P 〈 0.05）. Basal serum ACTH （9.91 ±4.98 pmol/L vs. 7.60 ±2.96 pmol/L） and dehydroepiandrosterone sulfate （2123.7 ±925.8 μg/L vs. 1417.1 ±498.4 μg/L） levels were significantly higher in IHH patients with NAFLD than those without NAFLD （all P 〈 0.05）. We also found that basal serum ACTH levels were positively correlated with NAFLD （r = 0.289, P 〈 0.05） and triglyceride levels （r - 0.268, P 〈 0.05） in male IHH patients. Furthermore, NAFLD was independently associated with ACTH levels in male IHH patients by multiple linear regression analysis. Conclusions： The male IHH patients showed higher basal serum ACTH levels and lower cortisol levels than matched healthy controls. NAFLD was an independent associated factor for ACTH levels in male IHH patients. These preliminary findings provided evidence of the relationship between basal serum ACTH and NAFLD in male IHH patients.