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Owing to highly theoretical capacity of 3579 mAh/g for lithium-ion storage at ambient temperature, silicon (Si) becomes a promising anode material of high-performance lithium-ion batteries (LIBs). However, the large volume change (∼300 %) during lithiation/delithiation and low conductivity of Si are challenging the commercial developments of LIBs with Si anode. Herein, a sandwich structure anode that Si nanoparticles sandwiched between carbon nanotube (CNT) and silicon carbide (SiC) has been successfully constructed by acetylene chemical vapor deposition and magnesiothermic reduction reaction technology. The SiC acts as a stiff layer to inhibit the volumetric stress from Si and the inner graphited CNT plays as the matrix to cushion the volumetric stress and as the conductor to transfer electrons. Moreover, the combination of SiC and CNT can relax the surface stress of carbonaceous interface to synergistically prevent the integrated structure from the degradation to avoid the solid electrolyte interface (SEI) reorganization. In addition, the SiC (111) surface has a strong ability to adsorb fluoroethylene carbonate molecule to further stabilize the SEI. Consequently, the CNT/SiNPs/SiC anode can stably supply the capacity of 1127.2 mAh/g at 0.5 A/g with a 95.6 % capacity retention rate after 200 cycles and an excellent rate capability of 745.5 mAh/g at 4.0 A/g and 85.5 % capacity retention rate after 1000 cycles. The present study could give a guide to develop the functional Si anode through designing a multi-interface with heterostructures.

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Objective: Many Chinese teenagers are experiencing high mental stress levels due to epidemic-related restrictions and closures. Mental stress can induce numerous associated symptoms, and physical exercise is considered to buffer mental stress. However, it remains unclear whether health motivation regulates the relationships among mental stress, physical exercise, and stress symptoms. This study examined whether mental stress events during the epidemic can predict stress symptoms, whether physical exercise can buffer mental stress, and whether the mental stress buffer effect is enhanced when health motivation regarding physical exercise is high. Methods: In total, 2,420 junior high school students (1,190 boys and 1,230 girls; 826 seventh-grade students, 913 eighth-grade students, and 681 ninth-grade students) from nine provinces nationwide were selected to investigate mental stress events, symptoms, health motivation, and physical exercise in adolescents. The hypothesis was tested with a multiple regression analysis. Results: A positive relationship between adolescent mental stress events and stress symptoms was observed, and an interactive relationship was found among health motivation, physical exercise, and mental stress factors. Specifically, the mental stress-buffering effect of physical exercise was significant only when health motivation was high. Conclusion: In the post-epidemic period, the influence of mental stress events on stress symptoms in adolescents was found to be buffered by physical exercise only in terms of high health motivation. This result highlighted the role of health motivation in the buffering effect of physical exercise on mental stress during an epidemic.

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Racism is a public health crisis-yet our knowledge remains limited about how different racial and ethnic groups cope with the stress of discrimination across the United States. Research suggests that ethnic identity plays a role in the relationship between perceived discrimination and mental health problems. The purpose of this study is to focus on whether a strong Japanese identity in Hawai'i can buffer the stress of discrimination to protect mental health. Data were from an anonymous survey of 222 students who self-identified as Japanese at a university in Hawai'i. The average age was 21 years, about half (53%) were women, and 10% were foreign-born. Less than half (42%) of the students self-reported ever experiencing discrimination in a lifetime due to race/ethnicity. However, non-specific unfair treatment based on the Everyday Discrimination Scale was self-reported by most students (90%). It primarily included being treated with less respect or courtesy than other people and people acting as if they were better than them. Levels of ethnic identity were assessed with the Multigroup Ethnic Identity Measure (mean, 2.07; range, 0-3). A statistically significant interaction effect was observed (ß = -0.50; P < .01), indicating a stronger ethnic identity counteracted the psychological distress associated with everyday discrimination. This finding suggested that strong Japanese identity, which involves pride and knowledge, participation in cultural practices, and a sense of belonging to one's ethnic group, can buffer the stress of frequent experiences of unfair treatment.

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High levels of cardiorespiratory fitness have the potential to buffer against physical and mental health impairments, which can result from exposure to occupational stress. Police officers are especially at risk of high psychosocial stress; therefore, effective intervention strategies are warranted. Given this background, the purpose of the present study was to examine whether police officers with different levels of cardiorespiratory fitness differ with regard to their (a) physiological stress reactivity during acute real-life stress situations, and (b) physiological recovery related to acute and chronic work stress. In total, 201 police officers took part in this study (M = 38.6 years, SD = 10.1, 35.8% females). Officers were contacted eight times on a smartphone during their workday, and asked to report their current level of positive and negative affect, as well as feelings of stress and anger. Physiological stress responses and recovery (heart rate variability) were assessed using Movisens EcgMove3 devices. The Åstrand bicycle ergometer test was used to assess participants' cardiorespiratory fitness. Chronic work stress was assessed using the effort-reward imbalance model and the job strain model. Multilevel modeling was used to test buffering effects of cardiorespiratory fitness on physiological stress reactivity. Linear regression was applied to test stress-buffering effects of cardiorespiratory fitness on physiological recovery. Results showed lowered physiological stress reactivity to acute work stress in officers with higher levels of cardiorespiratory fitness. However, these results were not consistent, with no effects occurring for feelings of anger, positive affect, and negative affect. Chronic work stress (effort-reward imbalance) was related to lower physiological recovery. Cardiorespiratory fitness was positively related to physiological recovery. Data did not support interactions between work stress and cardiorespiratory fitness on physiological recovery. To some extent, cardiorespiratory fitness seems to have the potential to buffer stress reactivity in police officers in acute stress situations. Therefore, we encourage promoting fitness programs which aim to enhance cardiorespiratory fitness in stressful occupations such as law enforcement. Improvements in cardiorespiratory fitness might further enhance physiological recovery from chronic work stress, which is thought to improve cardiovascular health.

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Approximately 20% of adolescents develop depressive symptoms. Family, friends, and teachers are crucial sources of social support for adolescents, but it is unclear whether social support impacts adolescents directly (principle-effect model) or by moderating the effect of stress (stress-buffer model) and whether each source of social support remains meaningful when their influence is studied simultaneously. To help fill this gap, we followed 1452 Australian students (average age at enrollment = 13.1, SD = 0.5; range: 11-16 years; 51.9% female) for 5 years. Based on our findings, each source of support is negatively related to depressive symptoms one year later when studied independently but when combined, only family and teacher support predicted depressive symptoms. Family support in all grades and teacher support in grade 8 to 10 but not in grade 11 directly impacted adolescent depressive symptoms 1 year later. Family support in grades 8 and 11 also buffered against the negative impact of stress on depressive symptoms one year later. Based on the unexpected findings, the most important limitations seem to be that the used instruments do not allow for a separation of different groups of friends (e.g., classmates, same-gender peers, romantic partners), types of social support, and stress. In addition, the high, nonrandom attrition rate with adolescents reporting less social support, more stressful events, a higher frequency of depressive symptoms, and/or being of Torres Strait Islander or Aboriginal background limits the generalizability of our findings. Summarized, our findings demonstrate that adolescents facing stress might benefit more from family support compared to their peers without stressful life events and that friends may have a weaker presence in adolescent lives than expected.

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