两相静止坐标系下消除不对称和谐波影响的同步信号提取方法

三相并网变流器可以在同步旋转坐标系下，也可以在两相静止坐标系下进行控制。无论在哪一种坐标系下进行控制，都需要能够快速准确地提取出电网同步信号。为了满足两相静止坐标系下变流器的控制需求，文中将正弦幅值积分器应用于两相静止坐标系下的同步信号提取。通过对在不对称和含有谐波情况下的输入电压进行矢量描述，提出采用多通道正弦幅值积分器的同步信号检测方法，可以消除负序分量和谐波分量的影响，而且无需进行正负序分离就可以直接得到正序分量和负序分量的幅值和相位信息。文中建立了多通道正弦幅值积分器同步信号提取方法的数学模型，揭示了同步信号提取的机理并讨论了反馈参数的选取原则。通过构造频率自适应算法，克服了电源频率变化对同步信号提取的影响。理论分析和实验结果都表明所提出的同步信号提取方法可以在电源频率变化、不对称以及含有谐波的情况下快速准确出提取出正负序分量的幅值和相位信号。     

Evaluation of Oxidative Metabolism in Child and Adolescent Patients with Attention Deficit Hyperactivity Disorder

Objective

Oxidative metabolism is impaired in several medical conditions including psychiatric disorders, and this imbalance may be involved in the etiology of these diseases. The present study evaluated oxidative balance in pediatric and adolescent patients with attention deficit hyperactivity disorder (ADHD).

Methods

The study included 48 children and adolescents (34 male, 14 female) with ADHD who had no neurological, systemic, or comorbid psychiatric disorders, with the exception of oppositional defiant disorder (ODD), and 24 sex- and age-matched healthy controls (17 male and seven female).

Results

TAS was significantly lower, and TOS and OSI were significantly higher in patients with ADHD than in healthy controls. Total antioxidant levels were lower in patients with comorbid ODD than in those with no comorbidity. No difference was found in TOS or OSI among the ADHD subtypes; however, TAS was higher in the attention-deficient subtype.

Conclusion

Our findings demonstrated that oxidative balance is impaired and oxidative stress is increased in children and adolescents with ADHD. This results are consistent with those of previous studies.     

钢铁企业工人心理资本在付出回报失衡、超负荷与工作倦怠关系中的调节与中介作用

目的：探讨钢铁企业工人心理资本在付出回报失衡、超负荷与工作倦怠关系中的调节与中介作用。方法随机选取某钢铁集团公司生产主线男性工人1700人,进行自填式问卷调查。调查内容包括一般情况、工作倦怠、付出回报失衡、超负荷、心理资本和感知的工作环境等。有效回收问卷1254份（73.76%）。采用分层回归分析检验调节作用,渐近—再抽样策略检验中介作用。结果心理资本对付出回报失衡与工作倦怠各维度之间的关系不存在调节作用,而对超负荷与情绪衰竭、玩世不恭之间关系有显著的正向调节作用;心理资本在付出回报失衡与情绪衰竭、玩世不恭之间关系中具有显著的中介作用,其中介效应量分别为5.84%和18.75%。结论心理资本水平高的工人,情绪衰竭和玩世不恭程度会随着超负荷的增加而明显上升;但心理资本水平低的工人,情绪衰竭和玩世不恭程度随着超负荷的增加而上升的趋势较弱。付出回报失衡降低钢铁工人心理资本存量进而导致情绪衰竭和玩世不恭。     

成人脊柱侧凸患者长时间行走后矢状面失平衡的动态评估

目的 评估成人脊柱侧凸患者长时间步行前后整体和局部的矢状面影像学参数。方法 回顾性纳入2016年1月至2018年6月于海军军医大学（第二军医大学）长征医院就诊的98例成人脊柱侧凸患者,根据行走前矢状面参数将患者分为两组：代偿组（行走前矢状面平衡,矢状面躯干偏移<40 mm且骨盆倾斜角>20°）和失代偿组（行走前矢状面失平衡,矢状面躯干偏移≥ 40 mm且骨盆倾斜角>20°）。步行15 min前后拍摄站立位全脊柱正侧位X线片,测量脊柱矢状面参数,包括矢状面躯干偏移、胸椎后凸角、腰椎前凸角、骨盆入射角、骨盆倾斜角、骶骨倾斜角。比较两组步行15 min前后脊柱矢状面参数,并对每组步行15 min前后矢状面躯干偏移变化值与其余矢状面参数变化值进行相关性分析。结果 代偿组19例,其中女16例、男3例,平均年龄为（64.1±5.9）岁,BMI为（24.2±4.6）kg/m²;失代偿组79例,其中女67例、男12例,平均年龄为（66.7±7.2）岁,BMI为（24.9±5.1）kg/m²,两组患者性别构成比、年龄、BMI差异均无统计学意义（P均>0.05）。步行前,代偿组患者腰椎前凸角大于失代偿组（Z=2.784,P=0.003）,骨盆入射角-腰椎前凸角和矢状面躯干偏移均小于失代偿组（Z=1.953,P=0.028;Z=3.815,P<0.01）;两组间骨盆倾斜角、骶骨倾斜角、胸椎后凸角差异均无统计学意义（P均>0.05）。步行15 min后,两组间骨盆倾斜角、骶骨倾斜角、腰椎前凸角、胸椎后凸角、骨盆入射角-腰椎前凸角、矢状面躯干偏移差异均无统计学意义（P均>0.05）。与步行前比较,代偿组和失代偿组患者步行15 min后骶骨倾斜角、骨盆入射角-腰椎前凸角、矢状面躯干偏移均增大（代偿组Z=1.718、P=0.043,Z=2.198、P=0.015,Z=3.875、P<0.01;失代偿组Z=1.842、P=0.031,Z=1.943、P=0.021,Z=2.917、P=0.002）,骨盆倾斜角和腰椎前凸角均减小（代偿组Z=1.639、P=0.047,Z=3.624、P<0.01;失代偿组Z=1.812、P=0.039,Z=3.893、P<0.01）;失代偿组患者步行15 min后胸椎后凸角也较步行前增大（Z=2.287,P=0.012）。代偿组、失代偿组患者步行15 min前后矢状面躯干偏移变化值均与骨盆倾斜角变化值呈负相关（r_s=-0.519、-0.625,P=0.024、0.001）,与骶骨倾斜角变化值、腰椎前凸角变化值、骨盆入射角-腰椎前凸角变化值均呈正相关（代偿组r_s=0.519、0.645、0.645,P均<0.05;失代偿组r_s=0.625、0.407、0.407,P均<0.01）。结论 成人脊柱侧凸患者长时间行走后矢状面平衡的代偿机制逐渐减弱或消失,骨盆及脊柱伸肌肌群的疲劳可能是代偿机制消失的原因。对于初次就诊时矢状面躯干偏移<40 mm、骨盆倾斜角>20°的患者,建议在行走15 min后再次拍摄X线片重新评估是否存在潜在的矢状面失平衡。     

Relationship between effort–reward imbalance and hair cortisol concentration in female kindergarten teachers

Objective

The present study aims to investigate the relationship between effort–reward imbalance and hair cortisol concentration among teachers to examine whether hair cortisol can be a biomarker of chronic work stress.

Methods

Hair samples were collected from 39 female teachers from three kindergartens. Cortisol was extracted from the hair samples with methanol, and cortisol concentrations were measured with high performance liquid chromatography–tandem mass spectrometry. Work stress was measured using the effort–reward imbalance scale.

Results

The ratio of effort to reward showed significantly positive association with hair cortisol concentration.

Conclusion

The cortisol concentration in the system increases with the effort–reward imbalance. Measurement of hair cortisol can become a useful biomarker of chronic work stress.     

Colchicine Overdose-Induced Acute Renal Failure and Electrolyte Imbalance

Colchicine has been used to control gouty arthritis for long time; colchicine overdose, however, causes multiple organ dysfunction. To date, no investigation has revealed the site of kidney lesion or dysfunction. This investigation describes the case of a male with a history of gout who ingested a large amount of colchicine and developed renal, hematopoietic, gastrointestinal, muscular, electrolytic, and hepatic disorder. Glucosuria was noted during hospital days. Colchicine intoxication is shown to induce proximal tubule damage. Severe electrolytes imbalance was noted, including hypomagnesemia, hypophosphatemia, and hypocalcemia. After management, the renal function and serum electrolyte of the patient recovered on the sixth day of hospitalization.     

Dynamic class imbalance learning for incremental LPSVM

Linear Proximal Support Vector Machines (LPSVMs), like decision trees, classic SVM, etc. are originally not equipped to handle drifting data streams that exhibit high and varying degrees of class imbalance. For online classification of data streams with imbalanced class distribution, we propose a dynamic class imbalance learning (DCIL) approach to incremental LPSVM (IncLPSVM) modeling. In doing so, we simplify a computationally non-renewable weighted LPSVM to several core matrices multiplying two simple weight coefficients. When data addition and/or retirement occurs, the proposed DCIL-IncLPSVM¹ accommodates newly presented class imbalance by a simple matrix and coefficient updating, meanwhile ensures no discriminative information lost throughout the learning process. Experiments on benchmark datasets indicate that the proposed DCIL-IncLPSVM outperforms classic IncSVM and IncLPSVM in terms of $F$-measure and $G$-mean metrics. Moreover, our application to online face membership authentication shows that the proposed DCIL-IncLPSVM remains effective in the presence of highly dynamic class imbalance, which usually poses serious problems to previous approaches.     

Effort–Reward Imbalance and Mental Health Problems in 1074 German Teachers,Compared with Those in the General Population

High degrees of premature retirement among teachers warrant investigating the occupational burden and the mental health status of this profession. A sample of 1074 German teachers participated in this study. Two samples of the general population (N = 824 and N = 792) were used as comparison groups. Work distress was assessed with the Effort–Reward‐Imbalance questionnaire, and mental health problems were measured with the General Health Questionnaire (GHQ‐12). Teachers reported more effort–reward imbalance (M = 0.64) compared with the general population (M = 0.57), and they perceived more mental health problems (GHQ: M = 12.1) than the comparison group (M = 9.5). School type was not associated with work stress and mental health. Teachers with leading functions perceived high degrees of effort and reward, resulting in a moderate effort–reward ratio and no heightened mental health problems. Teachers working full time reported more effort than teachers working part time, but the reward mean values of both groups were similar. This results in a somewhat unfavourable effort–reward ratio of teachers working full time. Moreover, teachers working full time reported more mental health problems. The results support the appropriateness of the effort–reward conception, applied to the profession of teachers. The higher degree of effort–reward imbalance and the level of mental health problems warrant preventive measures. Copyright © 2014 John Wiley & Sons, Ltd.     

轻型胰腺炎患者早期给予软食的临床研究

目的探讨轻型胰腺炎患者早期摄入软食的效果,为该类患者的营养支持提供参考。方法将72例轻型胰腺炎患者随机分为观察组与对照组各36例。对照组允许经口进食后按常规开始给予流质食物,观察组拟定饮食处方,早期给予低脂高热量高蛋白软食,比较两组营养状况、消化道症状、继发感染及住院时间。结果干预2周后,观察组血清蛋白显著高于对照组,肠道菌群失调发生率显著低于对照组,住院时间显著短于对照组,感染发生率显著低于对照组(P0.05,P0.01)。结论轻型胰腺炎患者早期进软食能提供充足营养素及能量,纠正营养不良状况,减少肠源性感染的发生,促进患者疾病转归和预后。