Improvement of roughness in ultrasonic assisted magnetorheological finishing of small titanium alloy nuts by orthogonal test method.

Titanium alloy with high corrosion resistance, high strength-to-density ratio, and excellent biocompatibility has a wide range of applications in the field of biomedical implants. Polishing experiments of titanium alloy with a small size and complex shapes were investigated using an ultrasonic assisted magnetorheological finishing (UMRF) device excited by a three-pole magnetic field generator. The models of the normal force and the shear force were first proposed based on the Preston equation to analyze the mechanism of material removal in the UMRF process. Subsequently, the single-factor experiments using titanium alloy nuts (M3) and the MR polishing fluid with silicon carbide abrasives were carried out. Furthermore, to improve the surface roughness and the change rate of surface roughness of nuts, orthogonal tests with a standard L9(34) orthogonal array were designed and performed based on the optimized process parameters obtained from the single-factor experiment. The results indicated the effect on surface roughness and change rate of surface roughness as applied current > roller speed > ultrasonic amplitude > spindle speed and applied current > roller speed > spindle speed > ultrasonic amplitude, respectively. Moreover, the surface roughness was improved from an initial 1.247 µm to a final 0.104 µm after the polishing for 80 min under these optimal process parameters.

Chrysanthemum morifolium as a traditional herb: A review of historical development, classification, phytochemistry, pharmacology and application.

ETHNOPHARMACOLOGICAL RELEVANCE: In recent years, Chinese herbal medicine has gained more and more recognition in disease prevention and control due to its low toxicity and comprehensive treatment. C. morifolium (Chrysanthemum morifolium Ramat.), as the medicine food homology plant with the bioactivity of anti-oxidation, anti-inflammatory, neuroprotection and cardiovascular protection, has important therapeutic effects and health benefits for colds, inflammation, cardiovascular diseases and various chronic diseases. AIM OF THE STUDY: By reviewing the historical development, classification and distribution of germplasm resources, phytochemistry, pharmacology, and modern application of C. morifolium, the paper provides a reliable basis for the further research and application of chrysanthemum as therapeutic agents and functional additives. MATERIALS AND METHODS: The literature and information about C. morifolium published in the last ten years were collected from various platforms, including Google Scholar, PubMed, ScienceDirect, Web of Science and China Knowledge Network. RESULTS: A comprehensive analysis confirmed that C. morifolium originated in China, and it went through the development process from food and tea to medicine for more than 3000 years. During this period, different cultivars emerged through several breeding techniques and were distributed throughout the world. Moreover, A variety of chemical components such as flavonoids, phenolic acids, volatile oils, and terpenes in chrysanthemum have been proven they possess various pharmacology of anti-inflammatory, anti-oxidant, and prevention of chronic diseases by regulating inflammatory cytokines, oxidative stress responses and signaling pathways, which are the essential conditions to play a role in TCM, nutraceuticals and diet. CONCLUSION: This paper provides a comprehensive review of historical development, classification, phytochemistry, pharmacology, and modern application of C. morifolium. However, future studies should continue to focus on the bioactive compounds and the synergistic mechanism of the "multi-component, multi-target, and multi-pathway" of chrysanthemum, and it is necessary to develop more innovative products with therapeutic effects.

Heatwave exposure in relation to decreased sleep duration in older adults.

Few studies have delved into the effects of heatwaves on sleep duration loss among older adults. Our study examined correlations between heatwave exposure and sleep duration reductions in this demographic. Utilizing data of 7,240 older adults drawn from the China Health and Retirement Longitudinal Study (CHARLS) from 2015 to 2018, we assessed sleep duration differences between the baseline year (2015) and follow-up year (2018). Absolute reductions in sleep duration were defined as differences of ≥ 1, 1.5, or 2 h. Changes in sleep duration were categorized based on cut-offs of 5 and 8 h, including excessive decrease, moderate to short and persistent short sleep duration types. 12 heatwave definitions combining four thresholds (90th, 92.5th, 95th, and 97.5th percentiles of daily minimum temperature) and three durations (≥2, ≥3 and ≥ 4 days) were used. Heatwave exposure was determined by the difference in the number of 12 preceding months' heatwave days or events in 2015 and the number of 12 preceding months' heatwave days or events in 2018. The results showed that increased heatwave events (defined as ≥ P90th percentile & lasting three days) were associated with a higher likelihood of ≥ 1-hour sleep reduction and persistent short sleep duration. An increase in heatwave event (defined as ≥ P95th percentile & lasting three days) was linked to shifts from moderate to short sleep duration. For the association between an absolute reduction in sleep duration and heatwave exposure, while higher thresholds signified greater sleep reduction risks, the effect estimates of longer durations were not uniformly consistent. We observed that air pollution and green space modified the relationship between heatwaves and sleep duration. Females, urban residents, and individuals with chronic diseases were identified as vulnerable populations. This study found that increased heatwave exposure was associated with a higher risk of sleep duration loss in older adults.

The effects of heatwave on cognitive impairment among older adults: Exploring the combined effects of air pollution and green space.

The association between heatwaves and cognitive impairment in older adults, especially the joint effect of air pollution and green space on this association, remains unknown. The present cohort study used data from waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 2008 to 2018. Heatwaves were defined as having daily maximum temperature ≥ 92.5th, 95th and 97.5th percentile that continued at least two, three and four days, measured as the one-year heatwave days prior to the participants' incident cognitive impairment. Data on the annual average air pollutant concentrations of fine particulate matter (PM2.5) and ozone (O3) as well as green space exposure (according to the Normalized Difference Vegetation Index (NDVI)) were collected. Time-varying Cox proportional hazards models were constructed to examine the independent effect of heatwaves on cognitive impairment and the combined effect of heatwaves, air pollution, and green space on cognitive impairment. Potential multiplicative interactions were examined by adding a product term of air pollutants and NDVI with heatwaves in the models. The relative excess risk due to interaction (RERI) was calculated to reflect additive interactions. We found that heatwave exposure was associated with higher risks of cognitive impairment, with hazard ratios (HRs) and 95 % confidence intervals (CIs) ranging from 1.035 (95 % CI: 1.016-1.055) to 1.058 (95 % CI: 1.040-1.075). We observed a positive interaction of PM2.5 concentrations, O3 concentrations, lack of green space, and heatwave exposure on a multiplicative scale (HRs for product terms >1). Furthermore, we found a synergistic interaction of PM2.5 concentrations, O3, lack of green space, and heatwave exposure on an additive scale, with RERIs >0. These results suggest that extreme heat exposure may be a potential risk factor for cognitive impairment in older adults. Additionally, coexposure to air pollution and lack of green space exacerbated the adverse effects of heatwaves on cognitive function.

Squeeze Behaviors of Magnetorheological Fluids under Different Compressive Speeds.

The compression tests under the unidirection for magnetorheological (MR) fluids have been studied at different compressive speeds. The results indicated that curves of compressive stress under different compression speeds at the applied magnetic field of 0.15 T overlapped well and were shown to be an exponent of about 1 of the initial gap distance in the elastic deformation region and accorded well with the description of continuous media theory. The difference in compressive stress curves increases significantly with an increasing magnetic field. At this time, the continuous media theory description could not be accounted for the effect of compressive speed on the compression of MR fluid, which seems to deviate from the Deborah number prediction under the lower compressive speeds. An explanation based on the two-phase flow due to aggregations of particle chains resulting in much longer relaxation times at a lower compressive speed was proposed to explain this deviation. The results have guiding significance for the theoretical design and process parameter optimization for the squeeze-assisted MR devices such as MR dampers and MR clutches based on the compressive resistance.

Energy Expenditure Estimation From Respiratory Magnetometer Plethysmography: A Comparison Study.

Physical activity (PA) quantification by estimating energy expenditure (EE) is essential to health. Reference methods for EE estimation often involve expensive and cumbersome systems to wear. To address these problems, light-weighted and cost-effective portable devices are developed. Respiratory magnetometer plethysmography (RMP) is among such devices, based on the measurements of thoraco-abdominal distances. The aim of this study was to conduct a comparative study on EE estimation with low to high PA intensity with portable devices including the RMP. Fifteen healthy subjects aged 23.84±4.36 years were equipped with an accelerometer, a heart rate (HR) monitor, a RMP device and a gas exchange system, while performing 9 sedentary and physical activities: sitting, standing, lying, walking at 4 and 6 km/h, running at 9 and 12 km/h, biking at 90 and 110 W. An artificial neural network (ANN) as well as a support vector regression algorithm were developed using features derived from each sensor separately and jointly. We compared also three validation approaches for the ANN model: leave one out subject, 10 fold cross-validation, and subject-specific. Results showed that 1. for portable devices the RMP provided better EE estimation compared to accelerometer and HR monitor alone; 2. combining the RMP and HR data further improved the EE estimation performances; and 3. the RMP device was also reliable in EE estimation for various PA intensities.

Combined effects of heatwaves and air pollution, green space and blue space on the incidence of hypertension: A national cohort study.

Extreme heat exposure has been associated with hypertension. However, its interactive influences with air pollution, green and blue spaces are unclear. This study aimed to explore the interaction between heatwaves, air pollution, green and blue spaces on hypertension. Cohort data enrolled 6448 Chinese older adults aged 65 years and over were derived from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) between 2008 and 2018. Nine heatwave definitions, combining three heat thresholds (92.5th, 95th, and 97.5th percentiles of daily maximum temperature) and three durations (≥2, 3 and 4 days) were used as time-varying variables in the analysis and were the one-year exposure before survival events. Fine particulate matter (PM ≤2.5 µm in aerodynamic diameter (PM2.5)), the Normalized Difference Vegetation Index (NDVI) and the average proportion of open water bodies were used to reflect the air pollution, green and blue space exposures, respectively. PM2.5, green and blue space exposures were time-varying indicators and contemporaneous with heatwaves. Mixed Cox models with time-varying variables were fitted to assess the multiplicative and additive interaction of heatwaves, PM2.5, and green and blue spaces on hypertension, measured by a traditional product term with the ratio of hazard ratio (HR) and relative risk due to interaction (RERI), respectively. A positive multiplicative (HRs >1) and additive interaction (RERIs >0) between heatwaves and higher PM2.5 levels was observed. There was a synergistic effect between heatwaves and decreasing greenness levels on hypertension incidence on additive and multiplicative scales. No significant interaction between heatwaves and blue space was observed in the analysis. The combined effects of heatwaves, air pollution, green and blue space exposures on the risk of hypertension varied with age, gender, and educational attainment. This study's findings complemented the existing evidence and revealed synergistic harmful impacts for heatwaves with air pollution and lack of green space on hypertension incidence.

The role of residential greenness levels, green land cover types and diversity in overweight/obesity among older adults: A cohort study.

BACKGROUND: Few studies have investigated the effects of greenness exposure, green land cover types and diversity and their interaction with particulate matter (PM) to adiposity. METHOD: Cohort data were collected from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Baseline data on greenness levels, green land cover types and diversity were assessed by the Normalized Difference Vegetation Index (NDVI), three greenery types (trees, shrublands and grassland) and Shannon's diversity index, respectively. Body mass index (BMI) and waist circumference (WC) were separately used as dependent variables and represented for peripheral overweight/obesity and central obesity, respectively. The mixed Cox model with random intercept was used to estimate the effects of greenness levels, types and diversity on overweight/obesity using single and multiple exposure models. We also examined the interaction of PM and the aforementioned indicators on overweight/obesity on both additive and multiplicative scales. RESULTS: Single exposure models showed that higher levels of residential greenness, tree coverage and ratio of trees to shrublands/grassland were inversely associated with peripheral overweight/obesity and central obesity. An increase in shrublands, grassland and diversity of green was related to lower odds of peripheral overweight/obesity. Multiple exposure models confirmed the association between greenness levels and peripheral overweight/obesity. Males, educated participants and elderly who lived in southern regions and areas with cleaner air environments acquired more benefits from greenspace exposure. Single and multiple exposure models indicated that an antagonistic effect of increasing PM and decreasing greenness levels on peripheral overweight/obesity and central obesity. Single exposure models showed the potential interaction of tree coverage, ratio of trees to grassland and PM2.5 exposures on the risk of peripheral overweight/obesity. CONCLUSION: Increasing residential greenness and diversity of green were associated with healthy weight status. The relationship between greenery and overweight/obesity varied, and the effects of greenspace exposure on overweight/obesity were associated with air pollution.

Energy Expenditure Estimation in Children, Adolescents and Adults by Using a Respiratory Magnetometer Plethysmography System and a Deep Learning Model.

PURPOSE: Energy expenditure is a key parameter in quantifying physical activity. Traditional methods are limited because they are expensive and cumbersome. Additional portable and cheaper devices are developed to estimate energy expenditure to overcome this problem. It is essential to verify the accuracy of these devices. This study aims to validate the accuracy of energy expenditure estimation by a respiratory magnetometer plethysmography system in children, adolescents and adults using a deep learning model. METHODS: Twenty-three healthy subjects in three groups (nine adults (A), eight post-pubertal (PP) males and six pubertal (P) females) first sat or stood for six minutes and then performed a maximal graded test on a bicycle ergometer until exhaustion. We measured energy expenditure, oxygen uptake, ventilatory thresholds 1 and 2 and maximal oxygen uptake. The respiratory magnetometer plethysmography system measured four chest and abdomen distances using magnetometers sensors. We trained the models to predict energy expenditure based on the temporal convolutional networks model. RESULTS: The respiratory magnetometer plethysmography system provided accurate energy expenditure estimation in groups A (R2 = 0.98), PP (R2 = 0.98) and P (R2 = 0.97). The temporal convolutional networks model efficiently estimates energy expenditure under sitting, standing and high levels of exercise intensities. CONCLUSION: Our results proved the respiratory magnetometer plethysmography system's effectiveness in estimating energy expenditure for different age populations across various intensities of physical activity.

Association between migration paths and mental health of new-generation migrants in China: The mediating effect of social integration.

Background: The new-generation migrants born in 1980 and later are large and vulnerable internal migrants in China. Migration paths and social integration are important factors to explain for their mental health. However, they faced difficulties in social integration varying from migration paths. We aimed to explore the mediating role of social integration between migration paths and the mental health of new-generation migrants. Methods: The migration paths included urban-to-urban, urban-to-rural, rural-to-urban and rural-to-rural. Mental health was assessed by the Kessler Screening Scale for Psychological Distress (K6) and the Perceived Stress Scales (PSS-4). Social integration was measured by economic integration, life integration, maintenance of the local culture, acceptance of the host culture and psychological integration. Multiple linear regressions with bootstrapping were used to examine the mediating effect. Results: A total of 9,830 new-generation migrants were included in this study. The mean age was 26.92 (SD = 4.47) years and the proportion of rural-to-urban migrants was 63.7%. Compared with the new generation of rural-to-rural migrants, rural-to-urban migrants had higher psychological distress (ß = 0.305, 95% CI: 0.152-0.458) and perceived stress (ß = 0.328, 95% CI: 0.199-0.456). The bootstrapping test found that two dimensions ("life integration" and "acceptance of the host culture") of social integration as a mediator weakened the negative effect of the rural-to-urban migration path on the mental health of new-generation migrants. Conclusion: Rural-to-urban migrants had poorer mental health, and the association was mediated by their poorer social integration. The migration policies developed to enhance social integration could effectively improve the mental health of new-generation migrants.

The impact of household wastewater on the frailty state of the elderly in China: based on a long-term cohort study in China.

China's household wastewater discharge has gradually increased, and its composition has become more complex, but the discharge treatment system is not perfect. At present, there is a lack of research on the impact of domestic wastewater on human health, especially on the frailty of the elderly. This study aimed to quantitatively assess the relationship between living wastewater and its main components and the frailty status of the elderly. The research data comes from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), which consists of participants over 60 years old who participated in the three-wave survey in 2008, 2011, and 2014 and combined with domestic wastewater data in the statistical yearbook. A generalized estimating equation (GEE) model was used to assess the link between living wastewater and frailty status in the elderly. The single-pollutant model showed that there was a positive correlation between the discharge of household wastewater and the frailty of the elderly, OR (4.443), 95%CI (3.591, 5.498); ammonia nitrogen had a positive correlation with the frail state of the elderly, OR (4.527), 95%CI (3.587, 5.714); chemical oxygen demand (COD) had a negative association with whether the elderly are frail, OR (0.776), 95%CI (0.609, 0.988). After adjusting for covariates, there was still a positive correlation between household wastewater and the frailty of the elderly, OR (2.792), 95%CI (2.233, 3.492); a positive correlation between ammonia nitrogen and the frail state of the elderly, OR (2.894), 95%CI (2.284, 3.666). The association between COD and the frail state of the elderly, OR (0.823), 95%CI (0.640, 1.058), showed no correlation between the two. The results show that household wastewater may affect the health of the elderly, promote the occurrence of a frail state of the elderly, and increase the medical burden.

Residential elevation and its effects on hypertension incidence among older adults living at low altitudes: a prospective cohort study.

BACKGROUND: Research on the relationship between residential altitude and hypertension incidence has been inconclusive. Evidence at low altitudes (i.e., <1,500 m) is scarce, let alone in older adults, a population segment with the highest hypertension prevalence. Thus, the objective of this study is to determine whether hypertension risk may be affected by altitude in older adults living at low altitudes. METHODS: This prospective cohort study collected data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We selected 6,548 older adults (≥65 years) without hypertension at baseline (2008) and assessed events by the follow-up surveys done in 2011, 2014, and 2018 waves. The mean altitude of 613 residential units (county or district) in which the participants resided was extracted from the Digital Elevation Model (DEM) of the National Aeronautics and Space Administration (NASA) and was accurate to within 30 m. The Cox regression model with penalized splines examined the linear or nonlinear link between altitude and hypertension. A random-effects Cox regression model was used to explore the linear association between altitude and hypertension. RESULTS: The overall rate of incident hypertension was 8.6 per 100-person years. The median altitude was 130.0 m (interquartile range [IQR] = 315.5 m). We observed that the exposure-response association between altitude and hypertension incidence was not linear. The shape of the exposure-response curve showed that three change points existed. Hypertension risk increased from the lowest to the first change point (247.1 m) and slightly fluctuated until the last change point (633.9 m). The risk decreased above the last change point. According to the categories stratified by the change points, altitude was only significantly associated with hypertension risk (hazard ratio [HR] = 1.003; 95% confidence interval [CI] = 1.002-1.005) under the first change point (247.1 m) after adjusting for related covariates. CONCLUSION: Our study found that the association between altitude and hypertension risk might not be linear. We hope the further study can be conducted to confirm the generality of our findings.

Metronidazole-resistant Clostridioides difficile: genomic and transcriptomic traits acquired under in-vitro metronidazole induction.

Decreased effectiveness of metronidazole for the treatment of Clostridioides difficile infection has been documented. One reason for this is that levels of metronidazole in the colon are generally low; therefore, a modest increase in the minimum inhibitory concentration of metronidazole for C. difficile may result in an insufficient therapeutic concentration. Due to the lack of efficient genetic manipulation tools for C. difficile strains, the resistance mechanism is largely unknown. In this study, a metronidazole-resistant strain (SH182IR) was acquired by in-vitro induction with metronidazole from a clinical metronidazole-heteroresistant strain (SH182), and the genomic and transcriptional changes were investigated through whole-genome sequencing and RNA-seq. The morphology of the two strains was studied by transmission electron microscopy, and the roles of drug efflux pumps in metronidazole resistance were determined by inhibition assay. Genomic analysis showed that the ferrous iron transporter feoB3 was truncated in SH182IR, indicating that feoB3 contributed to the metronidazole resistance of C. difficile. RNA-seq analysis showed that genes involved in peptidoglycan synthesis, efflux pumps and metronidazole reductive action were expressed differentially between the two strains. Further cell imaging confirmed that cell wall thickness was significantly greater in SH182IR. The efflux pump inhibitor test showed that addition of reserpine or cyanide 3-chlorophenylhydrazone reduced metronidazole resistance in SH182IR, thus proving the role of efflux pumps in metronidazole resistance. These results found an association between genomic variation and metronidazole resistance in C. difficile, and show that metronidazole resistance in C. difficile is multi-factorial, involving metronidazole metabolism, cell wall thickness and efflux pumps. These findings will help improve knowledge and understanding of metronidazole resistance of C. difficile.

Associations between Frailty and Ambient Temperature in Winter: Findings from a Population-Based Study.

Frailty is an accumulation of deficits characterized by reduced resistance to stressors and increased vulnerability to adverse outcomes. However, there is little known about the effect of ambient temperature in winter on frailty among older adults, a population segment with the highest frailty prevalence. Thus, the objective of this study is to investigate the associations between frailty and ambient temperature in winter among older adults. This study was based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS) of older adults aged ≥65 years from the 2005, 2008, 2011, and 2014 waves. The 39-item accumulation of frailty index (FI) was used to assess the frailty status of the participants. The FI was categorized into three groups as follows: robust (FI ≤ 0.10), prefrail (FI > 0.10 to <0.25), and frail (FI ≥ 0.25). Generalized linear mixed models (GLMMs) were conducted to explore the associations between frailty and ambient temperature in winter. A generalized estimating equation (GEE) modification was applied in the sensitivity analysis. A total of 9421 participants were included with a mean age of 82.81 (SD: 11.32) years. Compared with respondents living in the highest quartile (≥7.5 °C) of average temperature in January, those in the lowest quartile (<−1.9 °C) had higher odds of prefrailty (OR = 1.35, 95% CI 1.17−1.57) and frailty (OR = 1.61, 95%CI 1.32−1.95). The associations were stronger among the low-education groups, agricultural workers before retirement, and non-current exercisers. Additionally, results from the GEE model reported consistent findings. Lower levels of ambient temperature in winter were associated with higher likelihoods of prefrailty and frailty. The findings on vulnerability characteristics could help improve public health practices to tailor cold temperature health education and warning information.

Enhanced Anti-Atherosclerotic Efficacy of pH-Responsively Releasable Ganglioside GM3 Delivered by Reconstituted High-Density Lipoprotein.

Recently, the atheroprotective role of endogenous GM3 and an atherogenesis-inhibiting effect of exogenous GM3 suggested a possibility of exogenous GM3 being recruited as an anti-atherosclerotic drug. This study seeks to endow exogenous GM3 with atherosclerotic targetability via reconstituted high-density lipoprotein (rHDL), an atherosclerotic targeting drug nanocarrier. Unloaded rHDL, rHDL loaded with exogenous GM3 at a low concentration (GM3L-rHDL), and rHDL carrying GM3 at a relatively high concentration (GM3H-rHDL) were prepared and characterized. The inhibitory effect of GM3-rHDL on lipid deposition in macrophages was confirmed, and GM3-rHDL did not affect the survival of red blood cells. In vivo experiments using ApoE-/- mice fed a high fat diet further confirmed the anti-atherosclerotic efficacy of exogenous GM3 and demonstrated that GM3 packed in HDL nanoparticles (GM3-rHDL) has an enhanced anti-atherosclerotic efficacy and a reduced effective dose of GM3. Then, the macrophage- and atherosclerotic plaque-targeting abilities of GM3-rHD, most likely via the interaction of ApoA-I on GM3-rHDL with its receptors (e.g., SR-B1) on cells, were certified via a microsphere-based method and an aortic fragment-based method, respectively. Moreover, we found that solution acidification enhanced GM3 release from GM3-rHDL nanoparticles, implying the pH-responsive GM3 release when GM3-rHDL enters the acidic atherosclerotic plaques from the neutral blood. The rHDL-mediated atherosclerotic targetability and pH-responsive GM3 release of GM3-rHDL enhanced the anti-atherosclerotic efficacy of exogenous GM3. The development of the GM3-rHDL nanoparticle may help with the application of exogenous GM3 as a clinical drug. Moreover, the data imply that the GM3-rHDL nanoparticle has the potential of being recruited as a drug nanocarrier with atherosclerotic targetability and enhanced anti-atherosclerotic efficacy.

Ventilatory responses at submaximal exercise intensities in healthy children and adolescents during the growth spurt period: a semi-longitudinal study.

PURPOSE: To identify the changes of ventilation ([Formula: see text]E), tidal volume (VT) and respiratory frequency (fr) at different incremental step test intensities during maturation of children and adolescents. METHODS: A semi-longitudinal study was conducted on 68 healthy untrained boys and girls aged 11-17 years. The subjects were separated into three distinct age groups. [Formula: see text]E, VT and fr parameters were evaluated annually during 3 years by modifying incremental step test intensities according to ventilatory threshold (VTh) level (30, 60 and 90% of [Formula: see text]O2max). Absolute and relative values of ventilatory responses were analyzed and compared according to age and developmental phase. RESULTS: (1) Height, weight, lean body mass and vital capacity increased significantly from 11 to 17 years of age. (2) [Formula: see text]O2max, [Formula: see text]E, and VT increased during maturation even when exercise intensity changed, especially from 11 to 15 years of age. On the other hand, fr showed a decreasing trend. CONCLUSION: Increases of VT are the main reason for [Formula: see text]E increases during maturation of children. fr decreased independently of total body mass during maturation. [Formula: see text]E.kg-1 was stable despite intensity variations. VT.kg-1 increased significantly from 11 to 15 years then stabilized at 17 years. Lean body mass seems to explain the evolution of VT.kg-1 during maturation.

Factors Associated With Healthcare Workers' Insomnia Symptoms and Fatigue in the Fight Against COVID-19, and the Role of Organizational Support.

Background: Healthcare workers (HCWs) have been exposed to increased risks of insomnia and fatigue during the COVID-19 pandemic. In this study, we identify important risk factors associated with insomnia symptoms and fatigue among HCWs, and evaluate the effect of organizational support on insomnia and fatigue symptoms. Methods: This is an online cross-sectional survey of HCWs in China administered during the COVID-19 epidemic (from February 27, 2020 to March 12, 2020). We employed the AIS-8 scale for insomnia screening, and a self-reported ten-point scale to evaluate subjects' degrees of fatigue. We also designed a four-point scale to assess the degree of social support provided on an organizational level. Additionally, we conducted logistic regression analysis to identify risk factors. Results: This study included a total of 3,557 participants, 41% of which consisted of non-frontline HCWs and 59% of which was frontline HCWs. Of the non-frontline HCWs, 49% reported insomnia symptoms, and 53.8% reported a moderate to high degree of fatigue. Meanwhile, among the frontline HCWs, the percentages for insomnia and moderate to high fatigue were 63.4% and 72.2%, respectively. Additionally, frontline HCWs and HCWs employed at Centers for Disease Control and Prevention (CDCs) had elevated risks of insomnia and fatigue. However, with increased organizational support, insomnia symptoms decreased among frontline HCWs. Also, organizational support mitigated the positive correlation between daily working hours and degree of fatigue among HCWs. Conclusion: Frontline HCWs and staff in Chinese CDCs have been at a high risk of insomnia symptoms and fatigue during the fight against COVID-19. This study provides evidence for the positive effects of organizational support in relation to insomnia and fatigue among HCWs. This sheds light on government responses to the COVID-19 epidemic for other countries.

Compressions of magnetorheological fluids under instantaneous magnetic field and constant area.

Compressions of magnetorheological (MR) fluids have been carried out under instantaneous magnetic fields. The yield strength of the MR fluid in compressive mode has been derived by assuming that it was a transformed shear flow in Bi-visous model. The compressive stresses have experimentally studied under different magnetic fields, different initial gap distances and different compressive velocities. The nominal yield shear stresses of the compressed MR fluid under different influential factors have been calculated. The compressive stress increased in a power law as the applied magnetic field increased, while it decreased as the initial gap distance and the compressive velocity increased. With the increase of magnetic field, the difference between the nominal yield shear stress curves increased, and the exponents of the power law increased with the increase of the magnetic field strengths. A larger initial gap distance and a lower compressive velocity resulted in a higher nominal yield shear stress under the same instantaneous magnetic field. The achieved results of the nominal yield shear stress with magnetic field seemed to deviate from the prediction of dipole model, and the chain structure aggregation effect, the sealing effect and the friction effect by compression should be considered.

Utility of a Simple Scoring System in Differentiating Bacterial Infections in Cases of Fever of Unknown Origin.

BACKGROUND: Infectious disease is the leading cause of fever of unknown origin (FUO). Serum inflammatory markers historically used to diagnose bacterial infection have sufficient diagnostic sensitivity but low specificity. This study aimed to develop a simple scoring system for differentiating bacterial infections from other causes of early-stage FUO. METHODS: This study included a retrospective cohort of patients presenting with FUO at the Huashan Hospital (January 2014 to June 2017). The diagnostic utility of serum inflammatory markers for bacterial infection was evaluated using the receiver operating characteristic (ROC) curve analysis. Relevant markers were subsequently measured prospectively in a separate cohort of FUO patients (December 2017 to May 2019). A scoring system was based on inflammatory markers and other test results. RESULTS: Bacterial infection was identified in 34% of patients in the retrospective cohort. The area under the ROC curve (AUC) was 0.644 (95% confidence interval [CI], .595-.693) for C-reactive protein, 0.624 (95% CI, .573-.675) for procalcitonin, and 0.646 (95% CI, .595-.697) for serum ferritin (SF) in diagnosing bacterial infection. Bacterial infection was found in 29% of cases in the prospective cohort. A model based on serum amyloid A (SAA) and SF levels and neutrophil percentage yielded an AUC of 0.775 (95% CI, .695-.854). Validation analysis indicated lower probability (<15%) of bacterial infection for patients with a score <16.5 points. CONCLUSIONS: A scoring system based on SAA and SF levels and neutrophil percentage can help distinguish bacterial infection from other causes of FUO, potentially reducing antibiotic use.

Transcriptomics and metabonomics analyses of maternal DEHP exposure on male offspring.

The objectives of this study were to evaluate the effect of maternal Di-2-ethylhexyl phthalate (DEHP) exposure on male offspring and to explore the mechanism of changes with the metabolic alterations and differential genes. Pregnant female Sprague-Dawley (SD) rats were intragastrically administered with 600 mg/kg body weight of DEHP or corn oil (CON) throughout pregnancy and lactation. The growth of male offspring was investigated until 14 weeks old, the indices of blood were detected, and mechanism was studied using metabonomics and transcriptomics. Compared with the CON group, body weight, body length, food intake, body fat weight, Lee's index, organ coefficient, blood lipids, and oral glucose tolerance test (OGTT) of male offspring were not significantly changed in maternal DEHP group. However, serum biochemical indexes such as alanine transaminase (ALT), total protein (TP), albumin (ALB), blood urea nitrogen (BUN), and creatinine (CREA) were markedly reduced in maternal DEHP group (p < 0.05). In addition, insulin level was elevated and catalase (CAT) level was decreased notably in maternal DEHP group compared with the CON group (p < 0.05). Furthermore, thyroxine (T4) level was lower and thyroid stimulating hormone (TSH) level was higher in maternal DEHP group (p < 0.05). Metabonomics revealed seven principal metabolites were identified, including increased L-allothreonine, creatine, uric acid, retinyl ester, L-palmitoylcarnitine, and decreased glycocholic acid and LysoPC (18:3). Transcriptomics displayed 35 differential genes were involved in the mechanism of maternal DEHP exposure. Therefore, this research confirms the effect of a certain dose of maternal DEHP exposure on male offspring and understands exactly the mechanism of these changes with metabonomics and transcriptomics.