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Search Results: 1 - 10 of 33149 matches for " Yuming Guo "
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Solvent Effects on Preparation of Pd-Based Catalysts: Influence on Properties of Palladium and Its Catalytic Activity for Benzyl Alcohol Oxidation  [PDF]
Feifei Wang, Guifen Hao, Yuming Guo, Xiaoming Ma, Lin Yang
Open Journal of Metal (OJMetal) , 2017, DOI: 10.4236/ojmetal.2017.74005
Solvent effects are important for the solution preparation of nanoscale metal materials, in which the sizes and properties of the nanomaterials are greatly influenced by the solvents. In this study, a series of Pd/XC-72 catalysts were synthesized by a facile solvothermal method in solvents with different numbers of hydroxyl groups, including ethanol, ethylene glycol, and glycerine. The as-prepared catalysts Pd/XC-72(EA), Pd/XC-72(EG) and Pd/XC-72(GI) were characterized by XRD, TEM, TGA, ICP-MS and multipoint nitrogen adsorption-desorption experiments. It was found that Pd/XC-72(GI) had the highest metallic dispersion and the smallest particle size (4.9 nm). Furthermore, Pd/XC-72(GI) exhibited the best catalytic performance for solvent-free selective oxidation of benzyl alcohol while the catalytic activities of Pd/XC-72 catalysts decreased in the order: Pd/XC-72(GI) > Pd/XC-72(EG) > Pd/XC-72(EA).
A Displacement Based Analytical Model to Determine Residual Stress Components in a Finite Elastic Thin Plate with Hole-Drilling Method  [PDF]
Yuming Li, Boussad Abbes, Fazilay Abbes, Yingqiao Guo, Xiaolu Gong
Journal of Applied Mathematics and Physics (JAMP) , 2018, DOI: 10.4236/jamp.2018.68133
In order to measure the residual stress components in an elastic thin plate, the hole-drilling strain-gage method has been used. This method enables to determine the relation between the magnitudes and directions of the principal stresses and the strain relaxation about the hole. In the existing analytical models based on stress field, the formulations associated with the hole-drilling method are based on the assumption of an infinite plate, this may cause some errors for a finite plate and it’s difficult to validate these solutions by FE methods. Furthermore, in the composite, the displacement field is continuous but the stress field is not necessarily continuous, the displacement field based method has to be used. In the present paper an analyt-ical model based on a displacement field described by a function with coefficients to determine for a finite round thin plate is presented. The coefficients used in the displacement field are independent on the three residual stress components, and they are determined by minimization of the internal strain energy during the hole-drilling process. Once the coefficients in the dis-placement field are determined, three strains measured in three radial directions are utilized to determine the three residual stress components. The proposed analytical model can be also adapted to infinite plate by assuming that the diameter of the round plate tends to infinite.
Assessing the Short-Term Effects of Heatwaves on Mortality and Morbidity in Brisbane, Australia: Comparison of Case-Crossover and Time Series Analyses
Shilu Tong, Xiao Yu Wang, Yuming Guo
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037500
Abstract: Background Heat-related impacts may have greater public health implications as climate change continues. It is important to appropriately characterize the relationship between heatwave and health outcomes. However, it is unclear whether a case-crossover design can be effectively used to assess the event- or episode-related health effects. This study examined the association between exposure to heatwaves and mortality and emergency hospital admissions (EHAs) from non-external causes in Brisbane, Australia, using both case-crossover and time series analyses approaches. Methods Poisson generalised additive model (GAM) and time-stratified case-crossover analyses were used to assess the short-term impact of heatwaves on mortality and EHAs. Heatwaves exhibited a significant impact on mortality and EHAs after adjusting for air pollution, day of the week, and season. Results For time-stratified case-crossover analysis, odds ratios of mortality and EHAs during heatwaves were 1.62 (95% confidence interval (CI): 1.36–1.94) and 1.22 (95% CI: 1.14–1.30) at lag 1, respectively. Time series GAM models gave similar results. Relative risks of mortality and EHAs ranged from 1.72 (95% CI: 1.40–2.11) to 1.81 (95% CI: 1.56–2.10) and from 1.14 (95% CI: 1.06–1.23) to 1.28 (95% CI: 1.21–1.36) at lag 1, respectively. The risk estimates gradually attenuated after the lag of one day for both case-crossover and time series analyses. Conclusions The risk estimates from both case-crossover and time series models were consistent and comparable. This finding may have implications for future research on the assessment of event- or episode-related (e.g., heatwave) health effects.
Effects of temperature on mortality in Chiang Mai city, Thailand: a time series study
Yuming Guo, Kornwipa Punnasiri, Shilu Tong
Environmental Health , 2012, DOI: 10.1186/1476-069x-11-36
Abstract: A time series model was used to examine the effects of temperature on cause-specific mortality (non-external, cardiopulmonary, cardiovascular, and respiratory) and age-specific non-external mortality (<=64, 65–74, 75–84, and?>?=85?years), while controlling for relative humidity, air pollution, day of the week, season and long-term trend. We used a distributed lag non-linear model to examine the delayed effects of temperature on mortality up to 21?days.We found non-linear effects of temperature on all mortality types and age groups. Both hot and cold temperatures resulted in immediate increase in all mortality types and age groups. Generally, the hot effects on all mortality types and age groups were short-term, while the cold effects lasted longer. The relative risk of non-external mortality associated with cold temperature (19.35°C, 1st percentile of temperature) relative to 24.7°C (25th percentile of temperature) was 1.29 (95% confidence interval (CI): 1.16, 1.44) for lags 0–21. The relative risk of non-external mortality associated with high temperature (31.7°C, 99th percentile of temperature) relative to 28°C (75th percentile of temperature) was 1.11 (95% CI: 1.00, 1.24) for lags 0–21.This study indicates that exposure to both hot and cold temperatures were related to increased mortality. Both cold and hot effects occurred immediately but cold effects lasted longer than hot effects. This study provides useful data for policy makers to better prepare local responses to manage the impact of hot and cold temperatures on population health.Many studies have demonstrated that both hot and cold temperatures had adverse effects on mortality. For example, elevated ambient temperature and heat-waves were associated with excess deaths in 86 US cities [1]. High temperatures had significant impacts on deaths from all causes, chronic bronchitis, pneumonia, ischemic heart disease, and cerebrovascular disease in England and Wales [2]. McMichael et al. found a U-shaped temperatu
Poultry fat decreased fatty acid transporter protein mRNA expression and affected fatty acid composition in chickens
Jianmin Yuan, Bingkun Zhang, Yuming Guo
Journal of Animal Science and Biotechnology , 2012, DOI: 10.1186/2049-1891-3-17
Abstract: PF had no influence on intestinal morphology, weight, or DNA, RNA, or protein concentrations at 2, 4, and 6?wk of age. However, compared with SBO, PF significantly decreased FATP mRNA abundance at 4?wk (P?=?0.009) and 6?wk of age (P?<?0.001); decreased liver fatty acid-binding protein (L-FABP) mRNA abundance at 6?wk of age (P?=?0.039); and decreased C18:2 (P?=?0.015), C18:3 (P?<?0.001), C20:2 (P?=?0.018), Σ-polyunsaturated fatty acids (Σ-PUFA) (P?=?0.020), and the proportion of PUFA (P?<?0.001) in the intestinal mucosa and decreased C18:2 (P?=?0.010), C18:3 (P?<?0.001), C20:2 (P?<?0.001), Σ-PUFA (P?=?0.005), and the proportion of PUFA (P?<?0.001) in breast muscle at 6?wk of age.PF decreases FATP and L-FABP mRNA expression and decreased the proportion of PUFA in the intestinal mucosa and breast muscle.As an organ of nutrient absorption, the small intestine is very important for animals. The capacity to absorb nutrients depends mainly on the development of the intestinal mucosa. A previous study showed that morphological characteristics of the small intestinal mucosa are affected by diet [1]. Dietary lipids could affect intestinal morphology [2-4], influencing the fatty acid (FA) composition of the apical enterocyte membrane [5] and the fluidity of brush border membranes [6]. This in turn could alter the transportation and diffusion of certain nutrients across the intestine [7].Poultry fat (PF), an available ingredient source, has been widely used as an energy source in swine feeds. A previous study showed that PF appeared to be more efficiently utilized than swine fat for both body weight (BW) gain and the production of carcass energy [8] and did not influence swine performance compared with soybean oil (SBO) [9]. However, few data exist on the effect of PF on the development of intestinal structure and on the absorption and utilization of FA compared with other animal fats or plant oil.Recently, there has been an increasing interest in improving the quality of meat.
Effects of Air Pollution on Disease Respiratory: Structures Lag  [PDF]
Amaury de Souza, Yuming Guo, Hamilton Germano Pav?o, Widinei Alves Fernandes
Health (Health) , 2014, DOI: 10.4236/health.2014.612163
Abstract: Objective: Little evidence is available on the association between ozone exposure and health in Campo Grande, Brazil. In this study, we aimed to examine the effects of surface ozone concentrations (O3) on respiratory morbidity in Campo Grande, Brazil during the period from January 1st, 2008 to December 31st, 2011. Methods: Daily data on respiratory hospital admissions, O3, mean temperature, and relative humidity were collected at Campo Grande, Brazil. A Poisson time series model was used to examine the effects of O3 on hospital admissions, while controlling for seasonality, long-term trend, temperature and relative humidity. A distributed lag non-linear function was used for O3, temperature, and relative humidity. We examined the effects of O3 on different age groups (0 - 4 years, 5 - 60 years and >60 years). Results: The ozone-respiratory morbidity relationship was non-linear, with a threshold at 13 ppb (less than 25% percentile of ozone distribution). We estimated the relative risk of hospital admission at 75% percentile of O3 distribution compared with associated with 25% of percentile of O3 distribution. The O3 effect on respiratory morbidity was delayed by two days and lasted for 4 days for all age groups except people aged 5 - 60 years. Children and the elderly were much more vulnerable to ozone pollution than people aged 5 - 60 years. Conclusions: This study suggests that ozone pollution has negative impacts on respiratory diseases in Campo Grande, Brazil. Children and the elderly were susceptible to O3 exposure. These findings should be used to develop policies for protecting people from O3 pollution.
Ambient temperature and coronary heart disease mortality in Beijing, China: a time series study
Zhaoxing Tian, Shanshan Li, Jinliang Zhang, Jouni Jaakkola, Yuming Guo
Environmental Health , 2012, DOI: 10.1186/1476-069x-11-56
Abstract: We examined the effects of temperature on CHD mortality using both time series and time-stratified case-crossover models. We also assessed the effects of temperature on CHD mortality by subgroups: gender (female and male) and age (age?>?=65 and age?<?65). We used a distributed lag non-linear model to examine the non-linear effects of temperature on CHD mortality up to 15 lag days. We used Akaike information criterion to assess the model fit for the two designs.The time series models had a better model fit than time-stratified case-crossover models. Both designs showed that the relationships between temperature and group-specific CHD mortality were non-linear. Extreme cold and hot temperatures significantly increased the risk of CHD mortality. Hot effects were acute and short-term, while cold effects were delayed by two days and lasted for five days. The old people and women were more sensitive to extreme cold and hot temperatures than young and men.This study suggests that time series models performed better than time-stratified case-crossover models according to the model fit, even though they produced similar non-linear effects of temperature on CHD mortality. In addition, our findings indicate that extreme cold and hot temperatures increase the risk of CHD mortality in Beijing, China, particularly for women and old people.There is strong evidence that extreme temperatures (e.g., cold spells and heat waves) have significant impacts on health [1,2]. Studies have shown that vulnerable people (e.g., elderly, children, and people with chronic diseases) will be affected greatly by extreme temperatures [3]. Coronary heart disease (CHD) patients constitute one of the largest groups of susceptible people [4-6]. As the second leading cause of cardiovascular death in the Chinese population, CHD accounts for 22% of cardiovascular deaths in urban areas and 13% in rural areas in China [7]. There is evidence that the incidence of CHD is steadily increasing in China [8], but the
Effects of Dietary Arginine and Methionine Levels on Broiler Carcass Traits and Meat Quality
Peng Jiao,Yuming Guo,Xin Yang,Fangyu Long
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2010.1546.1551
Abstract: The current trial with 4x2 factorial arrangement was carried out to determine the effects of dietary arginine and methionine levels on broiler carcass traits and meat quality. Four dietary levels of arginine were 80, 100, 120 and 140% of NRC recommendation and dietary levels of methionine were 100 and 120% of NRC recommendation. On day 42 of age, chickens from each group were slaughtered to evaluate carcass traits, meat quality and muscle characteristics. Arginine supplementation significantly improved muscle growth (pL<0.01), especially breast muscle growth while methionine showed no effect. For meat quality, arginine deficient diet resulted in decreased lightness (L* value) while methionine supplementation increased yellowness (b* value). Except for the arginine deficient group, shear force values were decreased with arginine supplementation. Total collagen was not affected by the levels of arginine and methionine while heat-soluble collagen was increased with arginine (pL<0.05) and methionine supplementation (p<0.05). The result of the present study indicated that dietary arginine and methionine could affect collagen property and myoglobin status in the final formation of meat characteristic and a level of dietary arginine up to 120% of the recommendation by NRC should be suggested for better lean meat deposition and meat tenderness.
An Axisymmetric Inverse Approach for Cold Forging Modeling
Ali Halouani,Yuming Li,Boussad Abbes,Ying-Qiao Guo
Lecture Notes in Engineering and Computer Science , 2010,
An Efficient Axi-symmetric Element Based on Inverse Approach for Cold Forging Modeling
Ali Halouani,Yuming Li,Boussad Abbes,Ying-Qiao Guo
Engineering Letters , 2010,
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