基于分类回归树模型的兰渝线陇南段铁路职工 血脂异常流行现状及影响因素分析*

摘 要：目的：基于兰渝线陇南段铁路职工健康体检数据,建立血脂异常发生风险的预测模型。方法：选取2016—2021 年参加健康体检的兰渝线陇南段铁路职工作为研究对象,评估并比较血脂正常与血脂异常人群的体检指标。共纳入3 970 人,其中男性3 625人（91.31%）、女性345人（8.69%）。建立分类回归树模型预测血脂异常发生风险。结果：血脂正常人群 为2 794人（70.38%）,血脂异常人群为1 176人（29.62%）。同年度比较,血脂异常人群平均年龄、身体质量指数（BMI）均 显著高于血脂正常人群,且以男性和超重肥胖者居多;血脂异常人群甘油三酯、总胆固醇、低密度脂蛋白显著高于血脂正常 人群,高密度脂蛋白显著低于血脂正常人群;血脂异常人群收缩压 （除 2016 年外） 和舒张压均显著高于血脂正常人群。 2020年和2021年血脂异常人群的血糖值显著高于血脂正常人群。2019—2021年血脂异常伴高血压或糖代谢异常的人群占比 也显著升高。分类回归树模型分析结果显示,BMI是脂代谢异常重要的预测因素,当BMI超过22.78 kg/m2 时脂代谢异常占比 上升至43.40%;当BMI超过26.46 kg/m2 时脂代谢异常占比上升至57.50%。结论：兰渝线陇南段铁路职工血脂异常检出率为 29.62%,BMI是血脂异常重要的预测因素。     

在青藏铁路施工中阶梯式习服对急性重型高原病预防的作用

目的了解阶梯式习服在急性重型高原病(即高原肺水肿及高原脑水肿)预防中的作用。方法通过对2003年3—10月中旬进入青藏铁路西藏段(唐古拉山口至西藏拉萨段)施工的22200名施工人员重型急性高原病的发病情况调查,并对采用不同方式进入高原的发病情况进行比较,对采用阶梯式方式进入高原的发病情况进行分析。结果2003年7个月中,共计进入青藏铁路西藏段施工人员22200名,发生高原肺水肿184例(男180例,女4例,年龄20～45岁)及高原脑水肿155例(均为男性,年龄22～44岁),发病率分别为0.83%和0.70%。位于同海拔高度的阶梯式者与未习服者比较,未习服者的发病率明显高于阶梯式习服者。结论急性重型高原病的发病率随着海拔的升高而增高。平原大规模人群进入高原地区,采用阶梯式习服方式进入高原能有效降低急性重型高原病的发病率,而对于大规模人群急进高原,在海拔2500m左右建立习服站不失为一种较好的办法。     

Modeling the Average and Instantaneous Friction Coefficient of a Disc Brake on the Basis of Bench Tests

This article presents the results of tests conducted on the average and instantaneous friction coefficients of railway vehicle disc brakes. The tests were carried out independently of various states of wear on the friction linings and the brake disc. The requirements of the International Union of Railways (UIC) regarding the approval of brake linings for use were taken into account. Based on many years of research using a brake bench to test railway disc brakes, the authors developed multiple regression models for the average friction coefficient and fluctuations (tolerances) in the instantaneous friction coefficient and achieved 870 results. The models proposed three types of variables: the input braking parameters (speed, pressure, and mass to be braked), operational parameters (the wear on the friction linings and the brake disc), and design parameters (perforations in the form of holes on the disc surface). The above two models were validated on the basis of 384 brakes, and in subsequent stages a further evaluation was performed. The coefficients were determined to be, respectively, 0.99 for the model of the average friction coefficient and 0.71 for the model of tolerance (fluctuations) of the instantaneous friction coefficient.     

牦牛与迁饲黄牛及低海拔黄牛肺动脉干及肺组织形态的比较

目的:对牦牛和迁饲黄牛及低海拔黄牛肺动脉干与肺组织形态进行比较研究,获得高原土生或迁饲动物慢性低氧时适应进化的模式。方法:采集青海地区海拔3000~4000m的牦牛、2500 m的高山迁饲黄牛及甘肃平凉1300 m的低海拔黄牛的肺动脉干及肺组织,固定、切片、染色后行光镜和电镜比较观察。结果:55%的迁饲黄牛和98%牦牛肺动脉干中膜以弹性纤维及胶原纤维为主,而45%的迁饲黄牛和100%低海拔黄牛以弹性纤维及平滑肌增多为主,且平滑肌增多成团分布。牦牛和迁饲黄牛肺浆膜结构致密,间皮下以弹性纤维为主,而低海拔黄牛肺浆膜结构疏松,间皮下以胶原纤维为主。相比于迁饲黄牛,牦牛和低海拔黄牛肺终末细支气管黏膜纵行皱襞更明显,牦牛肺呼吸性细支气管黏膜上皮为单层或假复层柱状上皮,多数细胞可见到纤毛,并且黏膜仍有皱襞形成;而黄牛主要为单层柱状上皮,部分细胞可见纤毛。迁饲黄牛肺内小动脉血管壁和微动脉管壁厚度增加,与牦牛及低海拔黄牛比较差异有统计学意义。结论:牦牛肺动脉干和肺组织形态与结构有适应高原的独特形式,迁饲黄牛在适应高原时发生了与牦牛一样的趋同性改变,同时又兼具低海拔黄牛的特点。     

Who are more at risk for acute mountain sickness: a prospective study in Qinghai-Tibet railroad construction workers on Mt. Tanggula

Background  It is important to determine the incidence of acute mountain sickness (AMS) among workers at altitudes between 3500 m and 5000 m on Mt. Tanggula during the construction of the Qinghai-Tibet railroad. This study explored the risk factors predisposing workers to developing AMS and attempted to develop more effective ways of preventing and treating AMS.

Methods  A total of 11 182 workers were surveyed by completing twice daily a Lake Louise questionnaire, and a score ≥3 indicated AMS. The contributing risk factors were assessed for at least 2 months for the duration of the study in the years from 2001 to 2003. A risk model was developed by multiple Logistic regression. Standard statistical methods were used to analyze data.

Results  AMS occurred in 56% of workers working at high altitudes on Mt. Tanggula. The incidence of AMS increased with increasing altitude. Rapid ascent to an altitude above 3500 m, sea-level or lowland newcomers, young people under 25 years of age, heavy physical exertion, obese person, and arterial oxygen saturation (SaO₂) below 80% were independent AMS risk factors. No significant association was found between AMS and sex or taking Rhodiola. Medical education contributed to an early diagnosis of AMS.

Conclusions  This study used the Lake Louise scoring system suggesting that it is a well-validated standard for field evaluation of AMS and for making an early diagnosis. These studies have described many variables regarding risk factors for the development of AMS. Risk factors which can be modified should be attended to, and the physicians should carry out check-ups and tests to identify subjects who are more at risk. Prevention consists in continuous gradual ascent, medical education, and prompt descent to avoid progression in patients with serious AMS. It is most important to effectively control the risk factors of AMS.

     

铁路待等客运站蜚蠊防制对策研究

目的：通过对蜚蠊种群、栖息生境和不同场所不同灭蟑方法灭效的调查研究,探讨铁路待等客运站的蜚蠊防制对策。方法：采用以环境防制防为主,加强监测、分类实施、重点防制等综合防制措施。结果：措施实施后２年各场所与实施前相比,斐蠊成、若虫密度分别降低７７．９９％－９０．２６％和７７．４８％－９８．２４％,卵鞘密度分别降低８５．００％－１００％和１００％;不同场所一次用药后３、７、１５、３０d蜚蠊成、若虫密度分别降低６６．６７％－８８．８９％、７４．１１％、－８８．００％、７０．００％－７９．０７％和７０．５９％－７５．７１％;重点部位蜚蠊成、若虫密度从实施前平均密度的２．３８－２．９３倍,分别降为１．１６－１．３０倍和０．３８－１．１８倍;而且减少了用药量,降低了灭蟑经费。结论：有效地控制了蜚蠊滋生繁殖,产生了一定的社会经济效益。     

上海铁路地区医疗机构消毒隔离工作的状况与对策

目的了解上海铁路地区医疗机构消毒隔离工作的状况.方法按照GB15982-1995、GB15981-1995、GB15980-1995和GB15979-1995的要求进行调查.结果1997～2000年上海铁路地区医疗用品细菌总数合格率分别为92.59%、97.06%、99.11%和98.70%,环境物体表面大肠菌群合格率为95.28%～100%,医疗用品HBsAg合格率均为100%,环境物体表面HBsAg合格率分别为93.10%、97.12%、100%和100%,使用中消毒液细菌总数、空气细菌总数、紫外线灯的辐射强度、压力蒸汽灭菌器及福尔马林消毒箱消毒效果合格率分别为98.04%～100%、80.46%～90.91%、84.93%～100%、88.24%～100%和40.00%～80.77%.结论上海铁路地区医疗机构消毒隔离效果尚可,但需加强室内空气、压力蒸汽灭菌器及福尔马林消毒箱的消毒工作.     

The kings cross fire: Psychological reactions

The psychological reactions of 50 survivors of the King's Cross fire, which hit London's underground railway system on the 18th day of November 1987, are described. Results are presented for the Impact of Event scale, the General Health Questionnaire (28-item version), the Eysenck Personality Questionnaire and a King's Cross Event Schedule. These are investigated in relation to (a) validity measures, (b) relationships between exposure and personality, and (c) spontaneous de-briefing. Two thirds of the sample had significant levels of psychological distress (meeting the caseness criterion on the GHQ). Both personality (neuroticism and L-scale) and degree of trauma exposure were related to subsequent reaction. Spontaneous debriefing was associated with subjective benefit. Transportation disasters present particular problems in relation to research and service delivery.     

我国铁路客运合理径路选择的研究

从我国铁路客运信息网的实际出发,采用结合线数方法将路网规模缩小后,描述了以距离与换线结合为单目标的启发性求解算法.该算法已通过编程实现并广泛应用.     

常驻青藏高原陆军军人症状自评量表2017版常模

目的 建立我国常驻青藏高原陆军军人症状自评量表(symptom check list 90,SCL-90)2017版常模.方法 采用SCL-90量表,采用整群抽样的方法,选取常驻青藏高原地区46个陆军单位10 239名军人为对象进行测评.结果①常驻青藏高原陆军军人SCL-90多数因子得分显著低于1999版、2005版和2016版军人常模(P＜0.01),但躯体化因子得分显著高于2005版和2016版常模(P＜0.01);②高原男性军人躯体化得分显著高于2016版男性常模(P＜0.01),独生子女在7个因子得分上显著低于非独生子女(P ＜0.05,P＜0.01),高中和中专组抑郁得分最低,本科大专及以上组偏执得分最高,双亲家庭军人的因子得分均显著低于单亲家庭(P＜0.05,P＜0.01);③士官躯体化、强迫、人际敏感、敌对、恐怖得分最高,士兵的抑郁、偏执得分最低(P ＜0.05,P＜0.01);指挥类军人躯体化因子得分最低,后勤类军人在强迫、抑郁因子得分上显著低于政工类和其他类军人(P＜0.01);④除恐怖和精神性因子外,常驻青藏高原陆军军人因子得分在不同海拔高度上差异存在统计学意义(P ＜0.05,P＜0.01).结论 建立了常驻青藏高原陆军军人症状自评量表的总体常模、性别常模、独生子女常模、家庭结构常模、文化程度常模、职级常模、工作类型常模和海拔高度常模.