Theoretical analysis of a white-light LED array based on a GaN nanorod structure.

Based on the experimentally demonstrated In content distribution in the InGaN/GaN quantum wells on a two-section GaN nanorod (NR) sidewall, a white-light light-emitting diode (LED) without phosphor is designed and simulated. Following the dependencies of the In diffusion length and incorporation ratio on NR geometric variables of a theoretical model, the height, radius, and tapering section geometry of the GaN NR are designed for controlling the relative intensities of a blue and a yellow emission component to mix into white light. The higher-In upper section of the NR is first excited to emit a relatively stronger yellow component when injection current is low. As the injection current increases, more current spreads into the lower-In lower section, eventually leading to a stronger blue emission component. The proposed NR LED structure provides an alternative solution for phosphor-free white-light generation.

Apoptosis induced by weisiensin B isolated from Rabdosia weisiensis C.Y. Wu in K562.

The ent-kaurane diterpenoid weisinensis B shows significant cytotoxicity to human chronic myeloid leukemia K562 cells. It inhibits cell growth at low concentration and kills cells at high concentration. The compound induced cell apoptosis and necrosis mainly associated with G2/M phase cell cycle arrest and the ROS generation is the early event in weisiensin B induced cell apoptosis.

Perceived overqualification and knowledge sharing: The role of organizational identity and psychological entitlement.

BACKGROUND: Employees' perception of being overqualified is a critical factor in influencing their knowledge sharing behavior. However previous studies have not examined the internal mechanism by which perceived overqualification affects knowledge sharing. OBJECTIVE: Drawing on social exchange theory, the present study aimed to explore the relationship between perceived overqualification and knowledge sharing and to examine the mediating effect of organizational identity and the moderating role of psychological entitlement. METHODS: Participants were 284 full-time employees from different companies in China. They answered self-report questionnaires that assessed perceived overqualification, knowledge sharing, organizational identity, and psychological entitlement. Path analyses were conducted, and the latent moderated structural equations were used to judge the significance of the mediation and moderation. RESULTS: The results revealed that overqualified employees were less willing to share knowledge, and the mediating role of organizational identity was significant. Further, the presence of high psychological entitlement would diminish the beneficial effect of organizational identity on employee knowledge sharing. CONCLUSIONS: The findings of the study enrich and expand our knowledge on the relationship between overqualification and knowledge sharing and have theoretical and practical implications for promoting constructive behavior among overqualified employees.

Impact of the COVID-19 pandemic lockdown on Body Mass Index: a three-year follow up study in 6,156 Chinese college students.

Background: The novel coronavirus disease 2019 as the most pervasive and consequential pandemic in recent years, has exerted significant impacts on human health, including aspects related to body weight. Objectives: This study aims to assess the influence of the lockdown measures implemented during the COVID-19 pandemic on Chinese college students' Body Mass Index (BMI) through a three-year cohort study. Methods: We recruited 6156 college students (n = 4,248, 69% male, and n = 1,908, 31% female, with an average age of 18.68 ± 0.86 yr.) from a University in China to participate in this three-year cohort study. All of the subjects took the same physical fitness tests from 2019 to 2021 (pre-lockdown, during lockdown and post-lockdown). Participants' height and weight data were objectively measured by Tongfang Health Fitness Testing Products 5000 series. A paired t-test was performed in the analysis. Results: During the lockdown, there is 4.2% increase of BMI among the college student (p<0.001). Moreover, males had a greater overall mean BMI rate increase of 4.74% (p<0.001) than females (2.86%, p<0.001). After the lockdown, there is 0.94% increase of BMI among the college student (p<0.001). However, females had a greater overall mean BMI rate increase of 1.49% (p<0.001) than males (0.72%, p<0.001). During this period, the obese and overweight group's growth rate from 2019 to 2020 was smaller than the normal and underweight group, which were 2.94% (p<0.001), 3.90% (p<0.001), 4.44% (p<0.001) and 5.25% (p<0.001), respectively. Conclusion: BMI increased both during and post-lockdown periods among Chinese college students. However, during the lockdown, participants with higher BMI groups appeared to have a diminished BMI growth rate compared to those with lower BMI. After the lockdown, participants with higher BMI levels appeared to have an augmented BMI growth rate. Public policy action is needed to increase the level of physical activity of Chinese college students and take action to improve students' physical fitness performance after the lockdown.

Impact of the COVID-19 lockdown on physical fitness among college women living in China.

PURPOSES: The purpose of this study was to evaluate the effects of the COVID-19 lockdown on physical fitness among college women living in China and to explore how fitness changed with different physical conditions. METHODS: We performed repeated measures of BMI, 800 m running and sit-up performance assessment on college women from one university in China pre and post the COVID-19 lockdown. A total of 3658 (age 19.15 ± 1.08 yr.) college women who completed the same assessment pre and post the COVID-19 lockdown were included in the analysis. We analyzed the data using one way ANOVA and paired-samples t-test. RESULTS: Due to the COVID-19 lockdown, the result shows a significant increase in BMI by 2.91% (95% CI =0.33, 0.40) and a significant decline in 800 m running and sit-up by 7.97% (95% CI =0.69, 0.77) and 4.91% (95% CI = -0.27, -0.19), respectively. College women in the highest quartile level of physical condition (Quartile 4) had more decreases than college women in the lowest quartile level (Quartile 1). Their BMI level was increased by 3.69% and 0.98% in college women in Quartile 4 and Quartile 1, respectively. Their performance of 800 m running was decreased by 9.32% and 7.37% in college women in Quartile 4 and Quartile 1, respectively. Their performance of sit-up was decreased by 13.88% in college women in Quartile 4 while it increased by 10.91% in college women in Quartile 1, respectively. CONCLUSIONS: The COVID-19 lockdown might increase the BMI level and decrease 800 m running and sit-up performance among college women living in China. The decrease for college women in higher quartile level of physical condition (Quartile 4) were more seriously while college women in lower quartile level of physical condition (Quartile 1) were modest.

This study performed repeated tests on a large sample of 3658 college women before and after the COVID-19 lockdown to estimate the impact of COVID-19 on physical fitness.The COVID-19 lockdown decreased physical fitness (BMI, 800 m running and sit-up performance) among college women living in China.College women in higher level of physical condition at baseline were more seriously affected by the COVID-19 lockdown than college women in lower level of physical condition.

The Impact of Temperature on 24-Hour Movement Behaviors among Chinese Freshmen Students.

BACKGROUND: Human populations worldwide have experienced substantial climate change issues. Gaps in scientific literature remain regarding the relationship between temperature and 24-hour movement behavior among people. The purpose of this study is to examine the impact of temperature on 24-hour movement behavior including physical activity (PA), sedentary behavior (SB) and sleep duration among university students living in Beijing, China. METHODS: We conducted follow-up health surveys on 44,693 freshmen students enrolled at Tsinghua University from 2012 to 2018. PA and SB were measured by using the short version of the International Physical Activity Questionnaire (IPAQ-s); sleep duration was estimated by using The Pittsburgh Sleep Quality Index (CPSQI). Corresponding temperature data measured by the Beijing Meteorological Service were collected to include average daily temperature from the nearest weather station to Tsinghua university. The data were analyzed using linear individual fixed-effect regressions. RESULTS: An increase in temperature (temperature range 2.29-28.73 °C) by 1 °C was associated with an increase in 0.66 weekly minutes of vigorous physical activity (VPA) (95% confidence interval [CI] = 0.49, 0.82), an increase in 0.56 weekly minutes of moderate physical activity (MPA)(95% CI = 0.32, 0.79), an increase in 1.21 weekly minutes of moderate to vigorous physical activity (MVPA) (95% CI = 0.90, 1.53), an increase in 0.55 weekly minutes of walking (95% CI = 0.31, 0.78), an increase in 1.76 weekly minutes of total PA (95% CI = 1.35, 2.17), and a reduction in 1.60 weekly minutes of sleeping (95% CI = -2.09, -1.11). There was no significant correlation between temperature and sedentary behavior among participants. CONCLUSIONS: Temperature was significantly positively correlated with physical activity levels in the Chinese freshmen students, and significantly negatively correlated with sleep duration. Replication of this study is warranted among various populations within China. The evidence of this novel study focused on understanding the relationship between climate change and 24-hour movement behaviors among people for developing effective adaptation strategies to climate change to improve people's health behavior. This study has important implications for future study, as knowledge of the impact of temperature on movement behavior may help in the interpretation of their results and translate into improving people's health behavior.

The Impact of COVID-19 Restrictions on Physical Activity among Chinese University Students: A Retrospectively Matched Cohort Study.

Objectives: In this study, we estimated the impact of COVID-19 on physical activity (PA) for Chinese university students during the pandemic period. Methods: The International Physical Activity Questionnaire was completed online by 1487 students (947 males and 513 females; age 19.72 ± 1.32 years, BMI = 21.12 ± 4.50) from one university in China during the pandemic period, and students retrospectively recalled pre-pandemic PA levels (March 29- April 15, 2020). We analyzed the data using a paired-samples t-test. Results: Overall, COVID-19 produced a 27.89% reduction in total weekly minutes (40.62) of vigorous PA, a 43.38% reduction in total weekly minutes (73.92) of moderate PA, and a 24.36% reduction in total weekly minutes of walking (44.69). Results by sex showed that moderate PA decreased the most, by 47.15% (males) and 37.13% (females), and total PA decreased by 48.29% (males) and 40.18% (females). Conclusions: COVID-19 led to a reduction in PA among Chinese university students. PA decreased more for male than female students. Public policy action might be needed to increase the level of PA of Chinese university students.

Oridonin Induces Oxidative Stress-mediated Cancer Cells Apoptosis via Targeting Thioredoxin Reductase.

BACKGROUND: Thioredoxin reductase (TrxR) plays vital role in regulating cellular redox balance as well as redox-mediated signal transduction. Accumulating evidence supports that overactivation of TrxR is closely related to tumorigenesis and that targeting TrxR ablation reverses the growth of numerous malignant tumors, making TrxR a promising target for cancer chemotherapy. Thus, the discovery and development of molecules as promising anticancer agents that target TrxR is of great significance. Oridonin was shown to inhibit TrxR activity, but the detailed cellular mechanism is largely unknown. OBJECTIVE: The study investigated the mechanism of action and underlying inhibitory properties of oridonin on TrxR in HeLa cells. METHODS: A covalent docking was performed to reveal the possible interaction between oridonin and TrxR by Schrödinger Software Suite. TrxR activity was determined by 5,5'-dithiobis-2- nitrobenzoic acid reduction assay and endpoint insulin reduction assay. Sulforhodamine B and colony formation assay were employed to assess the viability and growth of cells. Reactive oxygen species level was measured by probe 2', 7'-dichlorfluorescein diacetate, and dihydroethidium. Hoechst 33342 staining, caspase 3 activation, and fluorescein-5-isothiocyanate-conjugated Annexin V and propidium iodide double staining were used to evaluate apoptosis. RESULTS: Here, we reported the oridonin as a potent inhibitor of TrxR. Inhibition of TrxR results in a decrease of thiols content and total glutathione, elevates reactive oxygen species levels, and finally promotes oxidative stress-mediated apoptosis of cancer cells. CONCLUSION: Targeting TrxR by oridonin discloses a novel molecular mechanism underlying the biological action of oridonin and sheds light on developing oridonin as a potential tumor therapeutic agent.

Impact of COVID-19 on 1000 m Running and Pull-Up Performance among College Men Living in China.

BACKGROUND: This study aimed to estimate the impact of the COVID-19 lockdown on fitness performance among Chinese college men during the pandemic period and to explore how fitness changed with a different college grade. METHODS: We conducted repeated measures of 1000 m running and pull-up testing on students from one university in China before and after the lockdown. A total of 7107 (age 19.21 ± 1.17 yr.) male students who completed the same 1000 m running and pull-up testing in 2019 and 2020 were included in the analysis. RESULTS: The paired t-test result indicates a reduction in 1000 m running and pull-up performance by 10.91% (95% CI = 0.89, 0.95) and 23.89% (95% CI = -0.36, -0.31), respectively. Interestingly, college men in the 2017 grade (the third-year college men) had more decreases than in the 2019 grade (the first-year college men). The 1000 m running performance was decreased by 14.43% and 6.48% in the third- and the first-year college men, respectively. The pull-up performance was decreased by 39.11 % in the third-year college men while increased by 10.98% in the first-year college men. CONCLUSIONS: The COVID-19 lockdown reduced 1000 m running and pull-up performances among Chinese college men. The reduction varies by grade and it seems to be particularly seriously decreased for the third-year college men while being modest for the first-year college men. Public policy was urgently needed to improve Chinese college men's fitness performance after the lockdown.

The Impact of COVID-19 Pandemic Restrictions on Sedentary Behavior Among Chinese University Students: A Retrospectively-Matched Cohort Study.

Purpose: This study was to estimate the impact of COVID-19 pandemic restrictions on sedentary behavior (SB) for Chinese university students during the pandemic period, as well as explore how sedentary behavior changed as a function of sex. Methods: We conducted an online questionnaire (the Sedentary Behavior Questionnaire) on students from one university in China during the pandemic period (March 29-April 15, 2020) and students retrospectively recalled pre-pandemic physical activity levels (before January 26, 2020). Sedentary behavior was measured using the short version of the Sedentary Behavior Questionnaire (SBQ). SB in a typical week during the COVID-19 pandemic period and before the COVID-19 pandemic restrictions were measured based on SBQ. The data was analyzed using a paired-samples t-test. Chi-square tests were to compare categorical variables. Results: A total of 1487 (947 males & 513 females; Age 19.72± 1.32yr., BMI = 21.12 ± 4.50) participated in this study. Before the COVID-19-associated lockdown restriction, on weekdays, survey participants averaged engaged in 11.41 (SD =3.93) hours of SB, 10.97 (SD = 3.85) hours of SB in males, 12.25 (SD =3.94) hours of SB in females; on weekends, survey participants averaged engaged in 13.18 (SD =4.06) hours of SB, 12.74 (SD = 3.96) hours of SB in males, 14.04 (SD =4.11) hours of SB in females. During the COVID-19-associated lockdown restriction, on weekdays, survey participants averaged engaged in 13.34 (SD =3.78) hours of SB, 12.90 (SD = 3.67) hours of SB in males, 14.19 (SD =3.83) hours of SB in females; on weekends, survey participants averaged engaged in 14.48 (SD =3.93) hours of SB, 14.10 (SD = 3.81) hours of SB in males, 15.22 (SD =4.04) hours of SB in females. Overall, on weekdays, The COVID-19-associated lockdown restriction on average appeared to increase SB by 1.93 (16.91%↑, 95% CI = 1.74, 2.12) hours, an increase in daily total SB by 1.92 (17.50%↑, 95% CI = 1.92, 2.15) hours for males, and an increase 1.94 (15.84%↑, 95% CI = 1.62, 2.27) hours in females. On weekends, The COVID-19-associated lockdown restriction on average appeared to increase SB by 1.30 (9.86%↑, 95% CI = 1.12, 1.48) hours, an increase in daily total SB by 1.36 (10.68%↑, 95% CI = 1.13, 1.58) hours for males, and an increase 1.18 (8.40%↑, 95% CI = 0.87, 1.50) hours in females. Conclusions: The COVID-19 restriction may lead to an increase in SB of Chinese university students. The total sedentary time of female students per week was higher than that of male students. Public policy action might be urgently needed to decrease the sedentary behavior of Chinese university students.

Anti-arthritic active fraction of Capparis spinosa L. fruits and its chemical constituents.

The aim of this study was to ascertain the anti-arthritic active fraction of Capparis spinosa L. (Capparidaceae) fruits and its chemical constituents. The adjuvant arthritic rat model was developed to evaluate the anti-arthritic effects of different fractions of ethanol extraction from C. spinosa L. The fraction eluted by ethanol-water (50:50, v/v) had the most significant anti-arthritic activity. The chemical constituents of this fraction were therefore studied; seven known compounds were isolated and identified as: P-hydroxy benzoic acid; 5-(hydroxymethyl) furfural; bis(5-formylfurfuryl) ether; daucosterol; α-D-fructofuranosides methyl; uracil; and stachydrine.

Accurate quantification of microRNA via single strand displacement reaction on DNA origami motif.

DNA origami is an emerging technology that assembles hundreds of staple strands and one single-strand DNA into certain nanopattern. It has been widely used in various fields including detection of biological molecules such as DNA, RNA and proteins. MicroRNAs (miRNAs) play important roles in post-transcriptional gene repression as well as many other biological processes such as cell growth and differentiation. Alterations of miRNAs' expression contribute to many human diseases. However, it is still a challenge to quantitatively detect miRNAs by origami technology. In this study, we developed a novel approach based on streptavidin and quantum dots binding complex (STV-QDs) labeled single strand displacement reaction on DNA origami to quantitatively detect the concentration of miRNAs. We illustrated a linear relationship between the concentration of an exemplary miRNA as miRNA-133 and the STV-QDs hybridization efficiency; the results demonstrated that it is an accurate nano-scale miRNA quantifier motif. In addition, both symmetrical rectangular motif and asymmetrical China-map motif were tested. With significant linearity in both motifs, our experiments suggested that DNA Origami motif with arbitrary shape can be utilized in this method. Since this DNA origami-based method we developed owns the unique advantages of simple, time-and-material-saving, potentially multi-targets testing in one motif and relatively accurate for certain impurity samples as counted directly by atomic force microscopy rather than fluorescence signal detection, it may be widely used in quantification of miRNAs.