31 research outputs found
Study on the Association between Ambient Air Pollution and Daily Cardiovascular and Respiratory Mortality in an Urban District of Beijing
The association between daily cardiovascular/respiratory mortality and air pollution in an urban district of Beijing was investigated over a 6-year period (January 2003 to December 2008). The purpose of this study was to evaluate the relative importance of the major air pollutants [particulate matter (PM), SO2, NO2] as predictors of daily cardiovascular/respiratory mortality. The time-series studied comprises years with lower level interventions to control air pollution (2003–2006) and years with high level interventions in preparation for and during the Olympics/Paralympics (2007–2008). Concentrations of PM10, SO2, and NO2, were measured daily during the study period. A generalized additive model was used to evaluate daily numbers of cardiovascular/respiratory deaths in relation to each air pollutant, controlling for time trends and meteorological influences such as temperature and relative humidity. The results show that the daily cardiovascular/respiratory death rates were significantly associated with the concentration air pollutants, especially deaths related to cardiovascular disease. The current day effects of PM10 and NO2 were higher than that of single lags (distributed lags) and moving average lags for respiratory disease mortality. The largest RR of SO2 for respiratory disease mortality was in Lag02. For cardiovascular disease mortality, the largest RR was in Lag01 for PM10, and in current day (Lag0) for SO2 and NO2. NO2 was associated with the largest RRs for deaths from both cardiovascular disease and respiratory disease
Prevalence of low back pain and associated occupational factors among Chinese coal miners
<p>Abstract</p> <p>Background</p> <p>Very few studies have evaluated the association between occupational factors and low back pain (LBP) among miners. The epidemiological data on LBP in Chinese miners are limited. The aim of this study was to measure the prevalence of low back pain in Chinese coal miners and to investigate the role of occupational factors.</p> <p>Methods</p> <p>A cross-sectional survey was conducted to examine 1573 coal miners in northern China. The prevalence of LBP over a 12-month period was assessed using the Nordic Musculoskeletal Questionnaire. Odds ratios were calculated to examine the association between the prevalence of LBP over a 12-month period and occupational factors using logistic regression.</p> <p>Results</p> <p>Among the coal miners, 64.9% self-reported LBP in a 12-month period. Occupational factors associated with LBP were identified, including tasks with a high degree of repetitiveness (OR 1.3, 95%CI 1.0-1.6), tasks characterized by a high level of physical demand (OR 1.4, 95% CI 1.1-1.8), posture requiring extreme bending (OR 1.6, 95% CI 1.2-1.7) and insufficient recovery time (OR 1.4, 95% CI 1.0-1.8).</p> <p>Conclusion</p> <p>Low back pain is common among Chinese miners. There were strong associations with occupational factors.</p
Induced Stress and Interaction of Fractures During Hydraulic Fracturing in Shale Formation
Creating complex fracture network by hydraulic fracturing operation in unconventional reservoir development is the key factor of effective exploitation. The mechanism of creating a fracture network is not clear up to today. Conventional hydraulic fracturing theory is based on tensile failure of a rock, and a hydraulic fracture is widely accepted as propagating along the direction of in situ maximum horizontal principal stress in the industry. Based on rock elastic mechanics and fracture mechanics, considering combined tensile and shear failures, the maximum circumferential strain criterion and boundary element method (BEM), the paper studies the induced stress and its variation during a fracture propagation, the interaction between two or more hydraulic fractures, and the interaction between a hydraulic fracture and a natural crack. The paper shows that a propagating fracture will produce induced stresses on surrounding rock and form a stress shadow. Instead of propagation along the direction of maximum horizontal principal stress as a single fracture, the outside two fractures of two or more hydraulic fractures are exclusive and turning away from each other. A natural crack may be awaked and extend at its both tips by a propagating hydraulic fracture before their intersection, and the hydraulic fracture may deflect toward the natural crack. The interaction between a hydraulic fracture and a natural crack depends on the transverse distance between them and the initial length of the crack. The shorter the transverse distance and the longer the crack length are, the higher the possibility of the crack to be awaked is. The research results are helpful in understanding complex fracture network and may be used in determining hydraulic fracture places to create a complex fracture network
Preparation and characterization of Fe3O4@nSiO2@mSiO2-NH2 core-shell microspheres for extracting allura red from aqueous solution
Allura red (AR) is a water-soluble synthetic colorant often used as an additive in the food industry, but excess AR can be harmful to human health. In this work, we report the development of a new removal method for AR by using amino-functionalized microspheres with Fe3O4 cores and twolayer shells composed of SiO2 particles and perpendicularly aligned mesoporous SiO2 (designated Fe3O4@nSiO2@mSiO2-NH2). The material exhibits good dispersibility in aqueous solutions and a high saturation magnetization of 45.68emug−1−1, and can be magnetically separated efficiently with an external magnet. Importantly, the material has great adsorption capacity of 29.6mgg−1−1 for AR and the capacity for reuse with a simple treatment. The adsorption process is very fast and the kinetics data are consistent with a pseudo-second order model. Based on these, a rapid and efficient method for extraction and analysis of AR in water and soft drinks has been established
Case report: Intrahepatic cholangiectasis with Clonorchis sinensis infection
Clonorchis sinensis infections persist globally among humans. These pathogens mainly inhabit the intrahepatic biliary system. Most individuals with clonorchiasis exhibit mild symptoms. The absence of distinctive symptoms often results in delayed diagnosis and treatment, potentially leading to chronic infection. We herein report a case of a 29-year-old female presented with a year-long history of abdominal distention and dyspepsia. Imaging revealed intrahepatic bile duct dilatation, intrahepatic bile duct cyst, and associated deposits. One month post-cystectomy, the patient developed massive ascites and a significant increase in eosinophil count. After treatment, multiple worms were observed in the drainage tube. Morphological and DNA metagenomic analyses confirmed the presence of C. sinensis. Clinical manifestations of C. sinensis vary widely. Imaging serves as a valuable diagnostic tool in endemic areas, especially in detecting intrahepatic duct dilation where the flukes reside. In addition to intrahepatic bile duct dilation, abnormal echoes within the bile duct and the presence of floating objects in the gallbladder significantly aid in diagnosis. Clinicians may encounter these parasitic diseases unexpectedly, underscoring the importance of understating such cases in routine practice and contributing to our broader understanding of managing similar cases in clinical settings