人类基础代谢率测量方法的研究进展

基础代谢率对于制定人群每日能量所需，科学指导膳食具有重要意义。目前基础代谢率有3种测量方法， 包括直接测热法、间接测热法和公式估算法。直接测热法难度较大不易实现，仅仅运用于某些特殊人群中；而间接 测热法和公式推测法是目前使用较多的两种方法。间接测热法准确性高，适用于有基础代谢测量需要的个体或公式 推测法的数据收集。公式推测法简便易行，适合大样本人群。     

A comparison between two powder compaction parameters of plasticity: The effective medium A parameter and the Heckel 1/K parameter

The purpose of the research was to introduce a procedure to derive a powder compression parameter (EM A) representing particle yield stress using an effective medium equation and to compare the EM A parameter with the Heckel compression parameter (1/K).     

膝关节固定后髌骨腱的生物力学改变

背景：骨关节固定常作为防止受伤组织被再次损伤的方法。 目的：膝关节固定对兔髌骨腱力学特性及超微形态的影响。 方法：将20只成年兔等分为固定组和对照组。固定组兔左后肢通过石膏和2个可调铝夹板，保持膝伸直，踝关节屈曲90°，固定6周后，取髌骨腱-骨复合物，观察两组髌骨腱的生物力学性能和超微结构变化。 结果与结论：膝关节固定6周拉伸强度和切线模量分别下降至对照组的64.44%和53.08%(P < 0.01)，但两组伸长率和最大负荷差异没有显著性意义。两组材料常数及应力应变关系曲线完全不同。固定组髌骨腱的横截面积明显大于对照组(P < 0.01)，小胶原纤维占有优势。说明固定不仅会导致髌骨腱生物力学的变化，而且对髌骨腱自身也产生影响。     

From the Cover: Efficient computation of optimal actions

Optimal choice of actions is a fundamental problem relevant to fields as diverse as neuroscience, psychology, economics, computer science, and control engineering. Despite this broad relevance the abstract setting is similar: we have an agent choosing actions over time, an uncertain dynamical system whose state is affected by those actions, and a performance criterion that the agent seeks to optimize. Solving problems of this kind remains hard, in part, because of overly generic formulations. Here, we propose a more structured formulation that greatly simplifies the construction of optimal control laws in both discrete and continuous domains. An exhaustive search over actions is avoided and the problem becomes linear. This yields algorithms that outperform Dynamic Programming and Reinforcement Learning, and thereby solve traditional problems more efficiently. Our framework also enables computations that were not possible before: composing optimal control laws by mixing primitives, applying deterministic methods to stochastic systems, quantifying the benefits of error tolerance, and inferring goals from behavioral data via convex optimization. Development of a general class of easily solvable problems tends to accelerate progress—as linear systems theory has done, for example. Our framework may have similar impact in fields where optimal choice of actions is relevant.     

Social support,resilience, and self-esteem protect against common mental health problems in early adolescence: A nonrecursive analysis from a two-year longitudinal study

The aim of this study is to examine the mutual effects of self-esteem and common mental health problems (CMHPs) as well as the mutual effects of self-esteem and resilience in early adolescence. The recruited participants were 1015 adolescents aged 12.7 years (SD = 0.5 years) from two junior high schools. Data were repeatedly collected at five time points at 6-month intervals over 2-year years. The Social Support Rating Scale (SSRS), Block and Kremen''s Ego-Resiliency Scale (ER89), Rosenberg Self-esteem Scale (RSES), and Mental Health Inventory of Middle School Students (MMHI-60) were used to measure social support, resilience, self-esteem, and CMHPs, respectively. Nonrecursive structural equation modeling (SEM) was performed to analyze the data.There were bivariate partial correlations among the five-time measurements for the SSRS, ER89, RSES, and MMHI-60 scores. Self-esteem negatively predicted CMHPs with a standardized direct effect of −0.276 (95% CI: −0.425 to −0.097), and the opposite effect was −0.227 (95% CI: −0.383 to −0.072). Self-esteem positively predicted resilience with the standardized direct effect of 0.279 (95% CI: 0.093–0.425), and the opposite effect was 0.221 (95% CI: 0.063–0.376). Social support was a protective factor for mental health status.The findings of mutual effects of self-esteem and CMHPs as well as self-esteem and resilience can provide researchers and practitioners with a conceptual framework that can help them build effective intervention methods to promote adolescent mental health status.     

Clinical Outcomes in Critically Ill Patients Associated With the Use of Complex vs Weight‐Only Predictive Energy Equations

Background: The energy intake goal is important to achieving energy intake in critically ill patients, yet clinical outcomes associated with energy goals have not been reported. Methods: This secondary analysis used the Improving Nutrition Practices in the Critically III International Nutrition Surveys database from 2007–2009 to evaluate whether mortality or time to discharge alive is related to use of complex energy prediction equations vs weight only. The sample size was 5672 patients in the intensive care unit (ICU) ≥4 days and a subset of 3356 in the ICU ≥12 days. Mortality and time to discharge alive were compared between groups by regression, controlling for age, sex, admission type, Acute Physiology and Chronic Health Evaluation II score, ICU geographic region, actual energy intake, and obesity. Results: There was no difference in mortality between the use of complex and weight‐only equations (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.86–1.15), but obesity (OR, 0.83; 95% CI, 0.71–0.96) and higher energy intake (OR, 0.65; 95% CI, 0.56–0.76) had lower odds of mortality. Time to discharge alive was shorter in patients fed using weight‐only equations (hazard ratio [HR], 1.11; 95% CI, 1.01–1.23) in patients staying ≥4 days and with greater energy intake (HR, 1.19; 95% CI, 1.06–1.34) in patients in the ICU ≥12 days. Conclusion: These data suggest that higher energy intake is important to survival and time to discharge alive. However, the analysis was limited by actual energy intake <70% of goal. Delivery of full goal intake will be needed to determine the relationship between the method of determining energy goal and clinical outcomes.     

Development of a Multivariate Prognostic Model for Pain and Activity Limitation in People With Low Back Disorders Receiving Physiotherapy

Objective

To identify predictors for back pain, leg pain, and activity limitation in patients with early persistent low back disorders (LBDs).

Quality of Life and Adaptation in People With Spinal Cord Injury: Response Shift Effects From 1 to 5 Years Postinjury

Objective

To investigate response shift effects in spinal cord injury (SCI) over 5 years postinjury.