中国大陆进口冷链食品关联新型冠状病毒疫情调查

目的 新型冠状病毒（SARS-CoV-2）全球大流行以来,中国大陆报道了多起SARS-CoV-2污染进口冷链食品引起的本土新冠疫情,分析此类疫情的特点和传播概况,可以为今后类似疫情防控提出相应建议。方法 收集SARS-CoV-2污染进口冷链食品引起本土新冠疫情文献、官方新闻报道等信息,整理和分析相应数据。结果 2020年6月至2022年11月,共检索到此类疫情20起,包含1 646例病例,涉及9个省（自治区、直辖市）。其中,2020年10起,2021年3起,2022年7起;病例数规模在200例及以上共3起。结论 新冠全球大流行以来中国大陆检索到的20起进口冷链食品相关本土新冠疫情均为冷链从业人员接触进口冷链食品或其外包装感染引起,且大部分（75%）引起了后续社区传播,但是在中国大陆集中监管仓建设等各种有力控制措施下,此类疫情数量和持续时间均呈下降趋势。     

微胶囊化儿茶素对阿霉素肾病大鼠总抗氧化能力的影响

目的:探讨微胶囊化儿茶素对阿霉素肾病大鼠总抗氧化能力的影响。方法:将60只雌性SD大鼠随机分为对照组、肾病组、激素组、VE组、儿茶素组和微胶囊组共六组,尾静脉一次性注射阿霉素(5mg/kg)制备肾病模型;实验第六周末杀鼠取尿、血、肾及肝脏,利用生化法测定血、肾及肝脏总抗氧化能力和·OH,利用考马斯亮蓝法测定24h尿蛋白的排泄量。结果:微胶囊组大鼠血、肾及肝脏中总抗氧化能力显著高于儿茶素组(p<0.01);微胶囊组大鼠·OH的浓度在肾与肝脏中显著低于儿茶素组(p分别<0.05,0.01),在血清中无显著性差异;微胶囊化儿茶素治疗组24h尿蛋白排泄量显著低于儿茶素治疗组(p>0.05)。结论:微胶囊化儿茶素可能是通过提高肾病大鼠总抗氧化能力,有效清除·OH,达到降低肾病大鼠尿蛋白排泄的目的。     

Role of water wettability,water transport,and adhesion in vision

Water plays an important role in life processes, although the specifics are not always known. In the past 25 years, major progress has been made in vision science by applying the principles and techniques of interface science to tear film physiology and pathophysiology, to novel surgical techniques, and to contact lens wear. In this paper, the role and structure of the preocular tear film are discussed, as well as the factors affecting its stability. This double-layered fluid film plays an important role not only in vision and the health of the exposed ocular tissues, but also in deciding contact lens tolerance and functioning. The little-known, misunderstood, and often misdiagnosed dry eye syndrome that is effected by the compromised stability of the tear film is also discussed. A newly recognized role of water as a bioabhesive in ocular tissue adhesion and its failure in terms of disjoining pressure and weak boundary layer are examined in the vision-threatening and painful adhesion failure of corneal epithelium and epithelial trauma during routine ophthalmic procedures such as tonography. The modalities to prevent undesirable contact adhesion in intraocular surgery that could result in surgical complications arc explored. Retinal tears are thought to result from the adhesion failure of the retina to the underlying tissues. A concentric double membrane model of retinal adhesion is proposed that analyzes the role of certain biophysical factors such as elasticity and hydraulic conductivity in promoting or diminishing the adhesion of retina to the choroid.     

Determination of worker physiological cost in workspace reach envelopes

Oxygen uptake (VO₂), heart rate (HR) and myoelectric activity (EMG) were measured while performing a repetitive task in the normal, maximum and extreme workspace reach envelopes. The VO₂ and HR increased significantly from the normal to the maximum to the extreme workspace reach envelope. The average increases in VO₂ when compared to the normal workspace were 19 and 52%, respectively. The corresponding average increases in HR were 6 and 14%, respectively. The increase in EMG for anterior deltoid, upper trapezious and erector spinae showed a significant increase from normal to maximum and from maximum to extreme workspaces. The average increases in EMG for anterior deltoid, upper trapezious and erector spinae, compared to the normal workspace were 96, 37 and 48% respectively for the maximum workspace and 193, 95 and 106% for the extreme workspace, respectively. The research indicated for the first time that during task performance, worker physiological cost would increase significantly with the increase in workspace reach levels.     

Differences in children and adolescents' ability of reporting two CVS-related visual problems

The present study examined whether children and adolescents can correctly report dry eyes and blurred distance vision, two visual problems associated with computer vision syndrome. Participants are 913 children and adolescents aged 6–17. They were asked to report their visual problems, including dry eyes and blurred distance vision, and received an eye examination, including tear film break-up time (TFBUT) and visual acuity (VA). Inconsistency was found between participants' reports of dry eyes and TFBUT results among all 913 participants as well as for all of four subgroups. In contrast, consistency was found between participants' reports of blurred distance vision and VA results among 873 participants who had never worn glasses as well as for the four subgroups. It was concluded that children and adolescents are unable to report dry eyes correctly; however, they are able to report blurred distance vision correctly. Three practical implications of the findings were discussed.

Practioner Summary: Little is known about children's ability to report their visual problems, an issue critical to diagnosis and treatment of children's computer vision syndrome. This study compared children's self-reports and clinic examination results and found children can correctly report blurred distance vision but not dry eyes.     

基于支持向量机的脾虚证多证型分类方法

本文针对脾虚证多证型分类问题,描述了二分类支持向量机的基本思想,分析比较了处理多分类问题的几种方法,进而依据“一对一”方法建立了多证型分类器,并应用于脾虚证的多证型诊断。作为结构风险最小化准则的具体实现,支持向量机具有全局最优性和较好的泛化能力。     

Risk of musculoskeletal disorders among females and males in repetitive/constrained work

This paper combines epidemiological data on musculoskeletal morbidity in 40 female and 15 male occupational groups (questionnaire data 3720 females, 1241 males, physical examination data 1762 females, 915 males) in order to calculate risk for neck and upper limb disorders in repetitive/constrained vs. varied/mobile work and further to compare prevalence among office, industrial and non-office/non-industrial settings, as well as among jobs within these. Further, the paper aims to compare the risk of musculoskeletal disorders from repetitive/constrained work between females and males. Prevalence ratios (PR) for repetitive/constrained vs. varied/mobile work were in neck/shoulders: 12-month complaints females 1.2, males 1.1, diagnoses at the physical examination 2.3 and 2.3. In elbows/hands PRs for complaints were 1.7 and 1.6, for diagnoses 3.0 and 3.4. Tension neck syndrome, cervicalgia, shoulder tendonitis, acromioclavicular syndrome, medial epicondylitis and carpal tunnel syndrome showed PRs > 2. In neck/shoulders PRs were similar across office, industrial and non-office/non-industrial settings, in elbows/hands, especially among males, somewhat higher in industrial work. There was a heterogeneity within the different settings (estimated by bootstrapping), indicating higher PRs for some groups. As in most studies, musculoskeletal disorders were more prevalent among females than among males. Interestingly, though, the PRs for repetitive/constrained work vs. varied/mobile were for most measures approximately the same for both genders. In conclusion, repetitive/constrained work showed elevated risks when compared to varied/mobile work in all settings. Females and males showed similar risk elevations. This article enables comparison of risk of musculoskeletal disorders among many different occupations in industrial, office and other settings, when using standardised case definitions. It confirms that repetitive/constrained work is harmful not only in industrial but also in office and non-office/non-industrial settings. The reported data can be used for comparison with future studies.     

The error analysis and improvement of portable metabolic rate detection system北大核心CSCD

In this paper, utilizing Monte Carlo simulation on the error model of portable metabolic rate detection system, obtained the final error indicators. Improved test circuit and used multi-sensor data fusion to achieve metabolic rate test instrument accuracy requirements in non-calibrated conditions. Through sensor error analysis and improvement, the accuracy of temperature test module of the project reached 0.15 ℃ (RMS). In addition, through the maximum likelihood estimate of the improvement circuit for data fusion, it can ensure that the test error is 0.124 ℃ (RMS) or less throughout the temperature testing process, meet the requirements of high accuracy of mass index, avoided the calibration process, reduced the cost of production. ©, 2014, The Editorial Office of Chinese Journal of Sensors and Actuators. All right reserved.     

Metabolic costs of load carriage with different container sizes

Abstract

Six well-trained male subjects carried boxes of varying box width and weight at varying speeds on a level treadmill until steady-state heart rates were obtained. Analysis of the steady-state data for heart rate and metabolic cost led to development of highly accurate predictor models for both factors. The metabolic-cost model accounted for over 94% of the variance (R²>0·94), and the heart-rate model accounted for over 81% of the variance present (R²>0·81). Evaluation of other models for predicting physiological response to carrying loads found their predictions to differ significantly from the data of the present study.     

Fast computation of minimal elementary decompositions of metabolic flux vectors

The concept of elementary flux vector is valuable in a number of applications of metabolic engineering. For instance, in metabolic flux analysis, each admissible flux vector can be expressed as a non-negative linear combination of a small number of elementary flux vectors. However a critical issue concerns the total number of elementary flux vectors which may be huge because it combinatorially increases with the size of the metabolic network. In this paper we present a fast algorithm that randomly computes a decomposition of admissible flux vectors in a minimal number of elementary flux vectors without explicitly enumerating all of them.