Ultrasonic reflection provides a real-time way to monitor oil film thickness in a running machine with a nondestructive advantage.However,the influence mechanism of temperature on reference signals has not been clarif...Ultrasonic reflection provides a real-time way to monitor oil film thickness in a running machine with a nondestructive advantage.However,the influence mechanism of temperature on reference signals has not been clarified thus far,which hinders the precise measurement of oil film thickness.Focusing on a common three-layer structure of sensor-adhesive-steel,a global propagation model is constructed to investigate variations in the reference signal with temperature.Through finite element simulations,distinct influence mechanisms are revealed for different components.For piezoelectric sensors and the adhesive layer,temperature may induce amplitude attenuation and wave extensions in the reference signal.In the steel component,only an overall time shift is observed in the reference signal.Subsequently,a compensation model is established and validated through temperature-controlled experiments.Within the effective bandwidth,the compensation model achieves a relative error of±2%and an absolute error of±0.02 radians for the amplitude and phase of the reference waves.展开更多
Background and Objectives:Current evidence on the associations of dietary eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)consumption with the risk of inflammatory bowel disease(IBD)is inconsistent.This study a...Background and Objectives:Current evidence on the associations of dietary eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)consumption with the risk of inflammatory bowel disease(IBD)is inconsistent.This study aimed to investigate the relationship between dietary EPA and DHA consumption with the incidence of IBD in a population of the United States,which potentially provides insights for global nutritional prevention and control strategies for IBD.Methods and S tudy Design:Data were sourced from the National Health and Nutrition Examination Survey for the years 2009-2010.EPA and DHA consumption was measured using twice 24-h dietary recall questionnaires.In the arthritis questionnaire,the incidence of IBD was inquired via a sub-analysis for arthropathy.To assess the relationship between dietary EPA and DHA consumption with the inci dence of IBD,binary logistic regression and limited cubic spline models were used.Results:A total of 4,242 in dividuals aged 20 years and older participated in this survey.IBD was diagnosed in 52 individuals,representing a prevalen ce of 1.23%.The 95%confidence interval for crude odds ratios(ORs)of IBD in quartiles 2 and 3 of die tary EPA co nsumption was 0.14(0.04-0.55)(p˂0.05)and 0.36(0.18-0.73)(p˂0.05)when compared to quartile 1,respectively.The 95%confidence interval f or crude ORs of IBD in quartile 4 of dietary DHA consumption was 0.09(0.02-0.35)(p˂0.05)when compared to quartile 1.Conclusions:For the National Health and Nutrition Ex amination Survey in 2009-2010,increased dietary EPA and DHA consumption may be rela ted to a decreased risk of IBD in Americans aged 20 and above.展开更多
Roller bearings support heavy loads by riding on an ultra-thin oil film(between the roller and raceway),the thickness of which is critical as it reflects the lubrication performance.Ultrasonic interfacial reflection,w...Roller bearings support heavy loads by riding on an ultra-thin oil film(between the roller and raceway),the thickness of which is critical as it reflects the lubrication performance.Ultrasonic interfacial reflection,which facilitates the non-destructive measurement of oil-film thickness,has been widely studied.However,insufficient spatial resolution around the rolling line contact zone remains a barrier despite the use of miniature piezoelectric transducers.In this study,a finite-element-aided method is utilized to simulate wave propagation through a three-layered structure of roller-oil-raceway under elastohydrodynamic lubrication(EHL)with nonlinear characteristics of the i)deformed curvature of the cylindrical roller and ii)nonuniform distribution of the fluid bulk modulus along the circumference of the oil layer being considered.A load and speed-dependent look-up table is then developed to establish an accurate relationship between the overall reflection coefficient(directly measured by an embedded ultrasonic transducer)and objective variable of the central oil-film thickness.The proposed finite-element-aided method is verified experimentally in a rollerraceway test rig with the ultrasonically measured oil-flm thickness corresponding to the values calculated using the EHLtheory.展开更多
Background and Objectives:Observational studies have shown that energy restriction could be beneficial for controlling bodyweight in patients with polycystic ovary syndrome(PCOS).We aim to compare the effects of a hig...Background and Objectives:Observational studies have shown that energy restriction could be beneficial for controlling bodyweight in patients with polycystic ovary syndrome(PCOS).We aim to compare the effects of a high-protein diet(HPD),a high-protein and high-dietary fiber diet(HPHFD),and a calorie-restricted diet(CRD)on metabolic health and gut microbiota in overweight/obese PCOS patients.Methods and Study Design:We will enroll a total of 90 overweight/obese PCOS patients into this eight-week open-label randomised controlled trial.Participants will be randomly assigned to three groups:CRD group(energy coefficient 20 kcal/kg.day,water≥1500 mL,0.8-1.2 g/kg protein,carbohydrate energize 55-60%,and fat energize 25-30%),HDP group(energy coefficient 20 kcal/kg.day,water≥1500 mL,and 1.5-2.0 g/kg protein)and HPHFD group(based on the high protein diet with 15 g more dietary fiber supplement).The primary outcome is body weight,body fat percentage,and lean body mass.The secondary outcomes will include changes in blood lipids,inflammation,glucose tolerance,blood pressure,and gut microbiota compositions.Between-group differences in adiposity measurements at baseline will be compared using one-way analysis of variance(ANOVA)or Kruskal-Wallis test when appropriate.Within-group difference after 8-week intervention will be compared using paired t-test or Wilcoxon signed rank test.Between-group differences in adiposity measurements after 8-week diet intervention will be compared using linear mixed model and ANCOVA.The gut microbiota will be analyzed using 16S amplicon sequencing and the sequencing data will be analyzed using the standardized QIIME2 piperline.展开更多
基金support from the National Natural Science Foundation of China(Nos.52405597,52275126,and 52105159)the Natural Science Basis Research Plan in Shaanxi Province of China(No.2024JCYBQN-0577).
文摘Ultrasonic reflection provides a real-time way to monitor oil film thickness in a running machine with a nondestructive advantage.However,the influence mechanism of temperature on reference signals has not been clarified thus far,which hinders the precise measurement of oil film thickness.Focusing on a common three-layer structure of sensor-adhesive-steel,a global propagation model is constructed to investigate variations in the reference signal with temperature.Through finite element simulations,distinct influence mechanisms are revealed for different components.For piezoelectric sensors and the adhesive layer,temperature may induce amplitude attenuation and wave extensions in the reference signal.In the steel component,only an overall time shift is observed in the reference signal.Subsequently,a compensation model is established and validated through temperature-controlled experiments.Within the effective bandwidth,the compensation model achieves a relative error of±2%and an absolute error of±0.02 radians for the amplitude and phase of the reference waves.
文摘Background and Objectives:Current evidence on the associations of dietary eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)consumption with the risk of inflammatory bowel disease(IBD)is inconsistent.This study aimed to investigate the relationship between dietary EPA and DHA consumption with the incidence of IBD in a population of the United States,which potentially provides insights for global nutritional prevention and control strategies for IBD.Methods and S tudy Design:Data were sourced from the National Health and Nutrition Examination Survey for the years 2009-2010.EPA and DHA consumption was measured using twice 24-h dietary recall questionnaires.In the arthritis questionnaire,the incidence of IBD was inquired via a sub-analysis for arthropathy.To assess the relationship between dietary EPA and DHA consumption with the inci dence of IBD,binary logistic regression and limited cubic spline models were used.Results:A total of 4,242 in dividuals aged 20 years and older participated in this survey.IBD was diagnosed in 52 individuals,representing a prevalen ce of 1.23%.The 95%confidence interval for crude odds ratios(ORs)of IBD in quartiles 2 and 3 of die tary EPA co nsumption was 0.14(0.04-0.55)(p˂0.05)and 0.36(0.18-0.73)(p˂0.05)when compared to quartile 1,respectively.The 95%confidence interval f or crude ORs of IBD in quartile 4 of dietary DHA consumption was 0.09(0.02-0.35)(p˂0.05)when compared to quartile 1.Conclusions:For the National Health and Nutrition Ex amination Survey in 2009-2010,increased dietary EPA and DHA consumption may be rela ted to a decreased risk of IBD in Americans aged 20 and above.
文摘Roller bearings support heavy loads by riding on an ultra-thin oil film(between the roller and raceway),the thickness of which is critical as it reflects the lubrication performance.Ultrasonic interfacial reflection,which facilitates the non-destructive measurement of oil-film thickness,has been widely studied.However,insufficient spatial resolution around the rolling line contact zone remains a barrier despite the use of miniature piezoelectric transducers.In this study,a finite-element-aided method is utilized to simulate wave propagation through a three-layered structure of roller-oil-raceway under elastohydrodynamic lubrication(EHL)with nonlinear characteristics of the i)deformed curvature of the cylindrical roller and ii)nonuniform distribution of the fluid bulk modulus along the circumference of the oil layer being considered.A load and speed-dependent look-up table is then developed to establish an accurate relationship between the overall reflection coefficient(directly measured by an embedded ultrasonic transducer)and objective variable of the central oil-film thickness.The proposed finite-element-aided method is verified experimentally in a rollerraceway test rig with the ultrasonically measured oil-flm thickness corresponding to the values calculated using the EHLtheory.
基金supported by grants from the Young Elite Scientists Sponsorship Program by CAST(China Association for Science and technology),No.YESS 20160186.
文摘Background and Objectives:Observational studies have shown that energy restriction could be beneficial for controlling bodyweight in patients with polycystic ovary syndrome(PCOS).We aim to compare the effects of a high-protein diet(HPD),a high-protein and high-dietary fiber diet(HPHFD),and a calorie-restricted diet(CRD)on metabolic health and gut microbiota in overweight/obese PCOS patients.Methods and Study Design:We will enroll a total of 90 overweight/obese PCOS patients into this eight-week open-label randomised controlled trial.Participants will be randomly assigned to three groups:CRD group(energy coefficient 20 kcal/kg.day,water≥1500 mL,0.8-1.2 g/kg protein,carbohydrate energize 55-60%,and fat energize 25-30%),HDP group(energy coefficient 20 kcal/kg.day,water≥1500 mL,and 1.5-2.0 g/kg protein)and HPHFD group(based on the high protein diet with 15 g more dietary fiber supplement).The primary outcome is body weight,body fat percentage,and lean body mass.The secondary outcomes will include changes in blood lipids,inflammation,glucose tolerance,blood pressure,and gut microbiota compositions.Between-group differences in adiposity measurements at baseline will be compared using one-way analysis of variance(ANOVA)or Kruskal-Wallis test when appropriate.Within-group difference after 8-week intervention will be compared using paired t-test or Wilcoxon signed rank test.Between-group differences in adiposity measurements after 8-week diet intervention will be compared using linear mixed model and ANCOVA.The gut microbiota will be analyzed using 16S amplicon sequencing and the sequencing data will be analyzed using the standardized QIIME2 piperline.
