萝卜硫烷对脑线粒体的影响:机理观点和未来发展方向

有机硫化物萝卜硫烷(SFN)是一种有效的细胞保护剂,在体外和体内实验模型中均可促进抗氧化、抗炎、抗糖化和抗菌作用。因为氧化磷酸化系统的存在,所以线粒体是三磷酸腺苷(ATP)的主要产生部位。同时,线粒体也是具核人体细胞中产生活性氧的主要场所。线粒体损伤在多种人类疾病中起着重要作用,包括神经退行性病变和代谢异常。本文描述和讨论了SFN调节哺乳动物细胞中线粒体功能和动力学的作用和机理,以及其对肿瘤细胞中线粒体促凋亡途径的促进作用。SFN对线粒体的调节作用使得它在一定程度上被认为是一种细胞保护剂。本文还指出了几个需要通过进一步实验解决的问题,即未来的可能研究方向,这可能会对该领域的研究人员具有指导作用。     

Effect of resistance training with different frequencies and subsequent detraining on muscle mass and appendicular lean soft tissue,IGF-1, and testosterone in older women

Objective: To analyse the effect of resistance training (RT) frequency on muscle mass, appendicular lean soft tissue, insulin-like growth factor 1 (IGF-1), testosterone, and their changes with detraining in older women. Methods: Forty-five physically independent older women (≥ 60?years) were randomly assigned to perform RT either two (G2X, n = 21) or three times/week (G3X, n = 24), during 12?weeks (8 exercises, 1 set of 10–15 repetition maximum). Muscle mass and appendicular lean soft tissue, IGF-1, testosterone, and dietary intake were measured at pre-training, post-training, and after detraining (12?weeks). Results: Muscle mass and appendicular lean soft tissue significantly increased post-training (G2X?=?+5.5% and G3X?=?+5.8%, P?P?P?Conclusion: We conclude that lower RT frequency is as effective as higher frequency to improve muscle mass and appendicular lean soft tissue, and to maintain testosterone and IGF-1. Additionally, detraining may reduce testosterone regardless of RT frequency. These results are specifically for community-dwelling older women and may not be generalized to other populations.     

Environmental Perception as a Diagnostic Probe of Environmental Complexity Levels

Purpose: Educational methods to diagnose and improve the level of environmental conception are required. The present work reports a methodology based on studies about the environmental perception of a university public, divided into general students and those related to the forest sciences, who are involved with disciplines and researches related to e.g. environmental management.

Design/Methodology/Approach: The environmental perception obtained from the graphical representation of environment and the most relevant actions indicated by the students to achieve the environmental conservation, divided in four levels of complexity, were correlated using principal component analysis.

Findings: The students from both groups having the highest scores in environmental perception prioritize actions related to the comprehension and responsibility levels, while the ideal scenario would be to indicate actions related to competence and citizenship. Thus, the complex concept about environment of the students is still incipient and, therefore, educational strategies can be traced based on the profiles obtained.

Practical Implications: The method for environmental perception can be designed for different populations and a scheme relating environmental perception with four levels of actions on behalf of the environmental conservation is proposed to diagnose environmental conceptions, as well as to guide educational strategies about socio-ecological system.

Originality/Value: A semi-quantitative method was developed to estimate, clearly and directly, the level of complexity about the environmental knowledge of university students and, consequently, to predict the actions on behalf of the environmental conservation that they would probably perform.     

Correction to: Epistemic and Political Confrontations Around the Public Policies to Fight COVID-19 Pandemic

Science & Education -     

Improved similarity-based modeling for the classification of rotating-machine failures

Similarity-based modeling (SBM) is a technique whereby the normal operation of a system is modeled in order to detect faults by analyzing their similarity to the normal system states. First proposed around two decades ago, SBM has been successfully used for fault detection in varied systems. In spite of this success, there is not much study performed in the literature regarding its design, that encompasses both similarity metrics and model training. This work aims at contributing with an in-depth study of SBM for fault detection considering these two design aspects. This is done in the context of proposing a novel system to identify rotating-machinery faults based on SBM, that is employed either as a standalone classifier or to generate features for a random forest classifier. New approaches for training the model and new similarity metrics are investigated. Experimental results are shown for the recently developed Machinery Fault Database (MaFaulDa) that has an extensive set of sequences and fault types, and for the Case Western Reserve University (CWRU) bearing database. Results for both databases indicate that the proposed techniques increase the generalization power of the similarity model and of the associated classifier, achieving accuracies of 98.5% on MaFaulDa and 98.9% on CWRU database.     

The improvement in walking speed induced by resistance training is associated with increased muscular strength but not skeletal muscle mass in older women

Objective: The purpose of the present study was to analyze whether improvements in fast walking speed induced by resistance training (RT) are associated with changes in body composition, muscle quality, and muscular strength in older women. Methods: Twenty-three healthy older women (69.6?±?6.4 years, 64.95?±?12.9?kg, 1.55?±?0.07?m, 27.06?±?4.6?kg/m²) performed a RT program for 8 weeks consisting of 8 exercises for the whole body, 3 sets of 10–15 repetitions maximum, 3 times a week. Anthropometric, body composition (fat-free mass [FFM], skeletal muscle mass [SMM], legs lean soft tissue [LLST], fat mass), knee extension muscular strength (KE1RM), muscle quality index (MQI [KE1RM/LLST]), and 10-meter walking test (10-MWT) were performed before and after the intervention. Results: Significant (P?<?.05) changes were observed from pre- to post-training for FFM (+1.6%), MQI (+7.2%), SMM (+2.4%), LLST (+1.8%), KE1RM (+8.6%), fat mass (?1.4%), and time to perform 10-MWT (?3.7%). The percentage change in 10-MWT was significantly associated with percentage change in MQI (r?=??0.46, P?=?.04) and KE1RM (r?=??0.45, P?=?.04), however not associated percentage of changes in SMM (r?=?0.01, P?=?.97), LLST (r?=??0.22, P?=?.33), and body fat (r?=?0.10, P?=?.66). Conclusion: We conclude that the improvement in the 10-MWT after an 8-week RT program is associated with increases in lower limb muscular strength and muscle quality, but not with muscle mass or body fat changes in older women.     

Not Only Why but Also How to Trust Science: Reshaping Science Education Based on Science Studies for a Better Post-pandemic World

Science & Education - Many authors blame postmodernism and studies on Sociology and Anthropology of Science (Science Studies) for the rise of relativism and anti-science movements. Despite such...     

On time-varying collaboration networks

The patterns of scientific collaboration have been frequently investigated in terms of complex networks without reference to time evolution. In the present work, we derive collaborative networks (from the arXiv repository) parameterized along time. By defining the concept of affine group, we identify several interesting trends in scientific collaboration, including the fact that the average size of the affine groups grows exponentially, while the number of authors increases as a power law. We were therefore able to identify, through extrapolation, the possible date when a single affine group is expected to emerge. Characteristic collaboration patterns were identified for each researcher, and their analysis revealed that larger affine groups tend to be less stable.     

The All-Heterosexual World of Children’s Nonfiction: A Critical Content Analysis of LGBTQ Identities in Orbis Pictus Award Books, 1990–2017

Despite increased attention toward children’s nonfiction and informational texts in recent decades, there is still little research that investigates the ways in which various cultural identities are depicted in nonfiction children’s books. Focusing specifically on the 143 winners and honor recipients of the Orbis Pictus Award for Outstanding Nonfiction Literature for Children (1990–2017), this article reports the findings of a critical content analysis of depictions of lesbian, gay, bisexual, transgender, and queer (LGBTQ) identified people in award-winning nonfiction youth literature. The authors look across this set of texts as a literary construction of the world, making explicit where and how LGBTQ people are visible in these award-winning books for young readers. By analyzing specific depictions of queer-identified people, the authors argue the creators of these books rely upon heteronormative constructions, queer erasure, and compulsory heterosexuality to minimize (and even eliminate) queerness.