AIM: To determine the prevalence and symptoms of gastroesophageal reflux disease (GERD) in a healthy general population in relation to demographic,lifestyle and health-seeking behaviors in Shiraz,southern Iran. METHOD...AIM: To determine the prevalence and symptoms of gastroesophageal reflux disease (GERD) in a healthy general population in relation to demographic,lifestyle and health-seeking behaviors in Shiraz,southern Iran. METHODS: A total of 1978 subjects aged > 35 years who referred to Gastroenterohepatology Research Center and who completed a questionnaire consisting of 27 questions for GERD in relation to demographic,lifestyle and health-seeking behaviors were included in this study for a period of five months. The validity and reliability of the questionnaire were determined. RESULTS: The prevalence of GERD was 15.4%,which was higher in females (17.3%),in rural areas (19.8%),and in illiterate subjects (21.5%) and those with a mean age of 50.25 years. The prevalence was significantly lower in subjects having fried food (14.8%),and fruit and vegetables (14.6%). More symptoms were noticed in subjects consuming pickles (22.1%),taking aspirin (21%) and in subjects with psychological distresses (27.2%) and headaches (22%). The correlation was statistically significant between GERD and halitosis (18.3%),dyspepsia (30.6%),anxiety (19.5%),nightmares (23.9%) and restlessness (18.5%). Their health seeking behavior showed that there was a significant restriction of diet (20%),consumption of herbal medicine (19%),using over-the-counter drugs (29.9%) and consulting with physicians (24.8%). Presence of GERD symptoms was also significantly related to a previous family history of the disease (22.3%).CONCLUSION: GERD is more common in females,rural and illiterate subjects and correlated with consumption of pickles,occurrence of headache,psychological distress,dyspepsia,halitosis,anxiety,nightmare and restlessness,and a family history of GERD and aspirin intake,but the correlation was negative with consumption of fat and fiber intake.展开更多
AIM: To determine whether hepatitis C virus (HCV) infection of index cases increases intrafamilial transmission (sexual and nonsexual contacts) of HCV. METHODS: In a case-control descriptive study we enrolled 300-hous...AIM: To determine whether hepatitis C virus (HCV) infection of index cases increases intrafamilial transmission (sexual and nonsexual contacts) of HCV. METHODS: In a case-control descriptive study we enrolled 300-household contacts of 60 index cases (40 males and 20 females) of HCV infection and 360 pair- matched controls in Ahwaz JundiShapour University Hospitals from August 1, 1998 to September 1, 2003. The control group consisted of first time blood donors referred to the Regional Blood Transfusion Organization. Serum samples and demographic data and a medical history including the existence of risk factors for HCV (after a questionnaire on the risk factors for parenteral exposure) were obtained from each subject. Antibodies to HCV were detected employing a commercially available second-generation enzyme immunoassay (EIA, Abbott Ⅱ). Positive serum specimens were retested using a second-generation recombinant immunoblot assay (RIBA-2) and a polymerase chain reaction for HCV RNA. Data analysis was carried out for intra-household clustering. RESULTS: Only 4 of 300 (1.33%) cases of household contacts without percutaneous risk factors were positive for HCV Ab while the remaining 296 family contacts were negative for anti-HCV. The mean age of the index cases was 28.4 (Std 15.22) years. The anti-HCV prevalences in parents, spouses, children of the index cases were 0.87% (1/115), 3.39% (2/59)) and 0.79% (1/126), respectively. Among couple partners negative for anti-HCV antibodies, the mean duration of the sexual relationship was 6 years.The two-couple partners positive for anti-HCV antibodies married the index cases for longer than 15 years. The prevalence of positive HCV Ab among household contacts (1.33%) was not significantly higher than that in the controls (1%) (P > 0.06). CONCLUSION: Intrafamilial transmission of HCV is not the significant transmission route and sexual transmission does not seem to play a role in the intrafamilial spread of HCV infection. Intrafamilial transmission of HCV is possible but occurs at a low rate.展开更多
AIM, To determine the prevalence of hepatitis B in Nahavand and evaluate the HBsAg positive prevalence in families with a member who was confirmed to have HBV infection. METHODS: This study was performed in two phase...AIM, To determine the prevalence of hepatitis B in Nahavand and evaluate the HBsAg positive prevalence in families with a member who was confirmed to have HBV infection. METHODS: This study was performed in two phases. In the first phase, 1 824 subjects in Nahavand city were selected. The interviewers visited the houses of chosen families to flU the questionnaire and take the blood samples. All subjects signed an informed consent before interviews and blood sampling. The samples were evaluated for HBV virologic markers. In the second phase, 115 HBsAg-positive cases were enrolled and evaluated for HBV virologic markers. RESULTS: The prevalence of positive HBsAg in Nahavand was 2.3%. The most frequent relatives of index cases were sons and daughters (32.2% and 23.5% respectively). Twelve (11%) of all family members were HBsAg positive. Fifty (56.2%) were isolated HBsAb positive and only one person (2.5%) was isolated HBcAb positive. The higher rates of HBsAg marker were detected in the brothers (1-25%) and fathers (1-12.5%). The infection rate in husbands and wives of index cases was 10%. Only two (16.7%) of all HBsAg-positive participants reported previous HBV vaccination. CONCLUSION: The prevalence of intr-familial HBV infection is lower in Nahavand of Iran compared to other studies. More attention should be paid to HBV vaccination and risk-lowering activities.展开更多
Pectenotoxins (PTXs) are a group of marine algal toxins. In this study, the accumulation and depuration of pectenotoxins in brown crab Cancer pagurus were investigated. Crabs were fed with toxic blue mussels Mytilus e...Pectenotoxins (PTXs) are a group of marine algal toxins. In this study, the accumulation and depuration of pectenotoxins in brown crab Cancer pagurus were investigated. Crabs were fed with toxic blue mussels Mytilus edulis for 21 days and then depurated for 42 days. Toxins were extracted with methanol from the digestive glands of contaminated crabs, uncontaminated crabs (control group) and from blue mussels for comparison. Extracts were analyzed by liquid chromatograph coupled with tandem mass spectrometry (LC-MS-MS). The concentrations of PTX-2, PTX-2 SA, 7-epi-PTX-2 SA, and PTX-12 were analyzed in two batches of toxic blue mussels and the crabs. A one-compartment model was applied to describe the depuration of PTXs. The half-life of PTXs was estimated to be 6–7.5 days. After depuration for 42 days, the amount of PTXs measured in the crab digestive glands was less than 1 μg/kg.展开更多
Natural frequencies for multilayer plates are calculated by mixed finite element method. The main object of this paper is to use the mixed model for multilayer plates, analyzing each layer as an isolated plate, where ...Natural frequencies for multilayer plates are calculated by mixed finite element method. The main object of this paper is to use the mixed model for multilayer plates, analyzing each layer as an isolated plate, where the continuity of displacements is achieved by Lagrange multipliers (representing static variables). This procedure allows us to work with any model for single plate (so as to ensure the proper behavior of each layer), and the complexity of the multilayer system is avoided by ensuring the condition of displacements by the Lagrange multipliers (static variables). The plate is discretized by finite element modeling based on a primary hybrid model, where the domain is divided by quadrilateral, both for the displacement field and static variables. This mixed element for plates was implemented and several examples of vibrations have been verified successfully by the results obtained by other methods in the literature.展开更多
AIM: To investigate the prevalence and risk factors of gastroesophageal reflux disease (GERD) symptoms in Qashqai migrating nomads with a different life style in Fars province, southern Iran. METHODS: In summer 20...AIM: To investigate the prevalence and risk factors of gastroesophageal reflux disease (GERD) symptoms in Qashqai migrating nomads with a different life style in Fars province, southern Iran. METHODS: In summer 2006, 748 Qashqai migrating nomads aged 25 years or more were enrolled using a multiple-stage stratified cluster random sampling method. A questionnaire consisting of demographic characteristics, lifestyle and GERD symptoms (heartburn, regurgitation, chest pain, dysphagia, hoarseness and cough) as completed for each subject. RESULTS: The questionnaire was completed in 717 subjects. The prevalence rate of GERD, defined as reflux occurring at least one time per week in the preceding year, was 33% (237 subjects). The prevalence was higher in older individuals (36.0% vs 28.9%, P 〈 0.05) and in those with other gastrointestinal complaints (51.0% vs 27.8%, P 〈 0.001), but not different in obese and non-obese subjects. It was also higher in those consuming fruits and vegetables more than once a week (36.2% vs 17.3%, P 〈 0.001). GERD had a positive correlation with smoking (42.1% vs 27.8%, P 〈 0.001), but a negative relation with non-alcoholic beverages. The association between GERD and non-steroidal antiinflammatory drugs (NSAIDs) consumption was also significant (40.2% vs 25.4%, P 〈 0.001). CONCLUSION: The prevalence of GERD (33%) is very high in Qashqai migrating nomads which may be due to a lower socioeconomic and educational level of these people and difference in the life style. Older age, frequent consumption of fruits and vegetables, smoking and NSAIDs are risk factors for GERD in this population.展开更多
This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, nor...This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, northern Iran. Galandrud coal on an air-dried basis are characterized by broad variation in the amount of ash (ranging from 6.49g to 12.73%), a high content of volatile matter (33,32-37.45%) and high gross calorific values (7430-8880 kcal/kg). The mineral matter of the coal samples studied is made up of dolomite (〉909g), quartz, sphalerite, galena, pyrite and clay minerals. Major elements are positively cor- related with ash content suggesting an association with inorganic constituents. Based on statistical anal- yses, concentrations of trace elements such as Co (51.3 ×10^-6-152.9× 10^-6), Ba (368× 10^-6-3297.4×10^-6), Cr (65.5 ×10^-6-194.2 × 10^-6), Mo (5.6 × 10^-6-18.2× 10^-6), Hi (72.9 × 10^-6-152.9 × 10^-6) and V (245.5 × 10^-6-520 ×10^-6) are higher than world coal averages. However, low concentration of some vol- atile elements such as As, Hg and U are present in low concentrations of the various types of coal studied.展开更多
Purpose: Trauma-related injuries are the leading cause of death worldwide. Some risk factors make trau- matic patients susceptible to infection. Furthermore, some mortality risk factors, including length of hos- pita...Purpose: Trauma-related injuries are the leading cause of death worldwide. Some risk factors make trau- matic patients susceptible to infection. Furthermore, some mortality risk factors, including length of hos- pitalization and increasing age, were detected in non-traumatic infected patients. This study aimed to assess mortality risk factors among nosocomial infected traumatic patients in Rajaee trauma center, Shiraz, Iran. Methods: This prospective cohort study was conducted during a period of 2 years since April 2015 to March 2017 in Rajaee hospital, which is the center of emergency medical services for traumatic injuries in Shiraz, Iran. Centers for Disease Control and Prevention/National Healthcare Safety Network surveil- lance system criteria were applied to define 5 types of nosocomial infections. The variables analyzed as the risk factors of infection and mortality included sex, age, mechanism of injury, site of injury, injury severity score (ISS), surgical intervention, length of hospitalization, intensive care unit (ICU) admission, and type of pathogen. Then, the incidence of nosocomial infection and also risk factors of mortality in traumatic patients were evaluated. All data analyses were performed using the statistical package for social sciences, version 15 (SPSS Inc., Chicago) and p 〈 0.05 is considered to be statistically significant. Results: The incidence of nosocomial infection was 7.2% (p 〈 0.001). Pneumonia was the most common type of infection detected in our study. Infection led to a 7.8-fold increase in mortality of the traumatic patients (p 〈 O.001 ). Admission in intensive care units and old age were the main risk factors of mortality in infected traumatic patients. Old age, gunshot and motor vehicle accidents, trauma to extremities and abdomen, higher injury severity score, and prolonged hospitalization, made the traumatic patients more susceptible to infection.展开更多
Using the concept of base forces as state variables,a new finite element method-the base force element method (BFEM) on complementary energy principle for linear elasticity problems is presented.Firstly,an explicit ex...Using the concept of base forces as state variables,a new finite element method-the base force element method (BFEM) on complementary energy principle for linear elasticity problems is presented.Firstly,an explicit expression of compliance matrix for an element is derived through base forces by dyadic vectors.Then,the explicit control equations of finite element method of complementary energy principle are derived using Lagrange multiplier method.Thereafter,the base forces element procedure for linear elasticity is developed.Finally,several examples are analyzed to illustrate the reliability and accuracy of the formulation and the procedure.展开更多
Uncertainty analysis and risk analysis are two important areas of modern water resource management,in which accurate variance estimation is required.The traditional runoff model is established under the assumption tha...Uncertainty analysis and risk analysis are two important areas of modern water resource management,in which accurate variance estimation is required.The traditional runoff model is established under the assumption that the variance is a constant or it changes with the seasons.However,hydrological processes in the real world are often heteroscedastic,which can be tested by McLeod-Li test and Engle Lagrange multiplier test.In such cases,the GARCH model of hydrological processes is established in this article.First,the seasonal factors in the sequence are removed.Second,the traditional ARMA model is established.Then,the GARCH model is used to correct the residual.At last,the daily runoff data in 1949-2001 of Yichang Hydrological Station is taken to be an example.The result shows that compared to the traditional ARMA model,the GARCH model has the ability to predict more accurate confidence intervals under the same confidence level.展开更多
Limited information is available on the distribution and origin of palygorkite in soils developed on Tertiary sediments as the major soil parent materials in central Iran and other Middle Eastern countries. The object...Limited information is available on the distribution and origin of palygorkite in soils developed on Tertiary sediments as the major soil parent materials in central Iran and other Middle Eastern countries. The objectives of this study were to determine the distribution and origin of palygorskite in soils developed on Tertiary sediments, and to identify the major soil properties that influence palygorskite distribution in the soils studied. Sixteen soil profiles developed on Paleocene, Eocene, Oligocene, Oligocene-Miocene, Miocene and Pliocene sediments were studied by X-ray diffraction analysis, transmission electron microscope, and scanning electron microscopy. Physicochemical characteristics of the soils and sediments including particle size distribution, pH, electrical conductivity, organic carbon, gypsum, carbonates, and soluble Si, Ca and Mg were determined. The principal component analysis was used to establish the relationships between palygorskite and the physicochemical characteristics of the soils studied. Results showed that clay fraction of all the soils in the study area was dominated by palygorskite. The highest amount of palygorskite was found in horizons where simultaneous accumulation of both carbonates and gypsum occurred. Limited amount of palygorskite was found in salic and calcic horizons. Palygorskite seemed to be of eolian origin in the surface horizon of all the soils. Using principal component analysis, the soluble Mg/Ca ratio, pH, soluble Si and gypsum contents were identified as the most important factors affecting the distribution and genesis of palygorskite in the soils studied. Results might suggest the neoformation of palygorskite by precipitation from solutions in which evaporation fluxes were very high. However, palygorskite in soils developed on Tertiary sediments in central Iran seems to be of both inherited and pedogenic origins.展开更多
文摘AIM: To determine the prevalence and symptoms of gastroesophageal reflux disease (GERD) in a healthy general population in relation to demographic,lifestyle and health-seeking behaviors in Shiraz,southern Iran. METHODS: A total of 1978 subjects aged > 35 years who referred to Gastroenterohepatology Research Center and who completed a questionnaire consisting of 27 questions for GERD in relation to demographic,lifestyle and health-seeking behaviors were included in this study for a period of five months. The validity and reliability of the questionnaire were determined. RESULTS: The prevalence of GERD was 15.4%,which was higher in females (17.3%),in rural areas (19.8%),and in illiterate subjects (21.5%) and those with a mean age of 50.25 years. The prevalence was significantly lower in subjects having fried food (14.8%),and fruit and vegetables (14.6%). More symptoms were noticed in subjects consuming pickles (22.1%),taking aspirin (21%) and in subjects with psychological distresses (27.2%) and headaches (22%). The correlation was statistically significant between GERD and halitosis (18.3%),dyspepsia (30.6%),anxiety (19.5%),nightmares (23.9%) and restlessness (18.5%). Their health seeking behavior showed that there was a significant restriction of diet (20%),consumption of herbal medicine (19%),using over-the-counter drugs (29.9%) and consulting with physicians (24.8%). Presence of GERD symptoms was also significantly related to a previous family history of the disease (22.3%).CONCLUSION: GERD is more common in females,rural and illiterate subjects and correlated with consumption of pickles,occurrence of headache,psychological distress,dyspepsia,halitosis,anxiety,nightmare and restlessness,and a family history of GERD and aspirin intake,but the correlation was negative with consumption of fat and fiber intake.
文摘AIM: To determine whether hepatitis C virus (HCV) infection of index cases increases intrafamilial transmission (sexual and nonsexual contacts) of HCV. METHODS: In a case-control descriptive study we enrolled 300-household contacts of 60 index cases (40 males and 20 females) of HCV infection and 360 pair- matched controls in Ahwaz JundiShapour University Hospitals from August 1, 1998 to September 1, 2003. The control group consisted of first time blood donors referred to the Regional Blood Transfusion Organization. Serum samples and demographic data and a medical history including the existence of risk factors for HCV (after a questionnaire on the risk factors for parenteral exposure) were obtained from each subject. Antibodies to HCV were detected employing a commercially available second-generation enzyme immunoassay (EIA, Abbott Ⅱ). Positive serum specimens were retested using a second-generation recombinant immunoblot assay (RIBA-2) and a polymerase chain reaction for HCV RNA. Data analysis was carried out for intra-household clustering. RESULTS: Only 4 of 300 (1.33%) cases of household contacts without percutaneous risk factors were positive for HCV Ab while the remaining 296 family contacts were negative for anti-HCV. The mean age of the index cases was 28.4 (Std 15.22) years. The anti-HCV prevalences in parents, spouses, children of the index cases were 0.87% (1/115), 3.39% (2/59)) and 0.79% (1/126), respectively. Among couple partners negative for anti-HCV antibodies, the mean duration of the sexual relationship was 6 years.The two-couple partners positive for anti-HCV antibodies married the index cases for longer than 15 years. The prevalence of positive HCV Ab among household contacts (1.33%) was not significantly higher than that in the controls (1%) (P > 0.06). CONCLUSION: Intrafamilial transmission of HCV is not the significant transmission route and sexual transmission does not seem to play a role in the intrafamilial spread of HCV infection. Intrafamilial transmission of HCV is possible but occurs at a low rate.
文摘AIM, To determine the prevalence of hepatitis B in Nahavand and evaluate the HBsAg positive prevalence in families with a member who was confirmed to have HBV infection. METHODS: This study was performed in two phases. In the first phase, 1 824 subjects in Nahavand city were selected. The interviewers visited the houses of chosen families to flU the questionnaire and take the blood samples. All subjects signed an informed consent before interviews and blood sampling. The samples were evaluated for HBV virologic markers. In the second phase, 115 HBsAg-positive cases were enrolled and evaluated for HBV virologic markers. RESULTS: The prevalence of positive HBsAg in Nahavand was 2.3%. The most frequent relatives of index cases were sons and daughters (32.2% and 23.5% respectively). Twelve (11%) of all family members were HBsAg positive. Fifty (56.2%) were isolated HBsAb positive and only one person (2.5%) was isolated HBcAb positive. The higher rates of HBsAg marker were detected in the brothers (1-25%) and fathers (1-12.5%). The infection rate in husbands and wives of index cases was 10%. Only two (16.7%) of all HBsAg-positive participants reported previous HBV vaccination. CONCLUSION: The prevalence of intr-familial HBV infection is lower in Nahavand of Iran compared to other studies. More attention should be paid to HBV vaccination and risk-lowering activities.
基金Supported by Norwegian Education Funding "Quata"(2005)
文摘Pectenotoxins (PTXs) are a group of marine algal toxins. In this study, the accumulation and depuration of pectenotoxins in brown crab Cancer pagurus were investigated. Crabs were fed with toxic blue mussels Mytilus edulis for 21 days and then depurated for 42 days. Toxins were extracted with methanol from the digestive glands of contaminated crabs, uncontaminated crabs (control group) and from blue mussels for comparison. Extracts were analyzed by liquid chromatograph coupled with tandem mass spectrometry (LC-MS-MS). The concentrations of PTX-2, PTX-2 SA, 7-epi-PTX-2 SA, and PTX-12 were analyzed in two batches of toxic blue mussels and the crabs. A one-compartment model was applied to describe the depuration of PTXs. The half-life of PTXs was estimated to be 6–7.5 days. After depuration for 42 days, the amount of PTXs measured in the crab digestive glands was less than 1 μg/kg.
文摘Natural frequencies for multilayer plates are calculated by mixed finite element method. The main object of this paper is to use the mixed model for multilayer plates, analyzing each layer as an isolated plate, where the continuity of displacements is achieved by Lagrange multipliers (representing static variables). This procedure allows us to work with any model for single plate (so as to ensure the proper behavior of each layer), and the complexity of the multilayer system is avoided by ensuring the condition of displacements by the Lagrange multipliers (static variables). The plate is discretized by finite element modeling based on a primary hybrid model, where the domain is divided by quadrilateral, both for the displacement field and static variables. This mixed element for plates was implemented and several examples of vibrations have been verified successfully by the results obtained by other methods in the literature.
基金Supported by Office of Vice Chancellor for Research, Shiraz University of Medical Sciences, Shiraz, Iran
文摘AIM: To investigate the prevalence and risk factors of gastroesophageal reflux disease (GERD) symptoms in Qashqai migrating nomads with a different life style in Fars province, southern Iran. METHODS: In summer 2006, 748 Qashqai migrating nomads aged 25 years or more were enrolled using a multiple-stage stratified cluster random sampling method. A questionnaire consisting of demographic characteristics, lifestyle and GERD symptoms (heartburn, regurgitation, chest pain, dysphagia, hoarseness and cough) as completed for each subject. RESULTS: The questionnaire was completed in 717 subjects. The prevalence rate of GERD, defined as reflux occurring at least one time per week in the preceding year, was 33% (237 subjects). The prevalence was higher in older individuals (36.0% vs 28.9%, P 〈 0.05) and in those with other gastrointestinal complaints (51.0% vs 27.8%, P 〈 0.001), but not different in obese and non-obese subjects. It was also higher in those consuming fruits and vegetables more than once a week (36.2% vs 17.3%, P 〈 0.001). GERD had a positive correlation with smoking (42.1% vs 27.8%, P 〈 0.001), but a negative relation with non-alcoholic beverages. The association between GERD and non-steroidal antiinflammatory drugs (NSAIDs) consumption was also significant (40.2% vs 25.4%, P 〈 0.001). CONCLUSION: The prevalence of GERD (33%) is very high in Qashqai migrating nomads which may be due to a lower socioeconomic and educational level of these people and difference in the life style. Older age, frequent consumption of fruits and vegetables, smoking and NSAIDs are risk factors for GERD in this population.
基金supported by the Iranian Institute for Geological Surveys and Mineral Exploration
文摘This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, northern Iran. Galandrud coal on an air-dried basis are characterized by broad variation in the amount of ash (ranging from 6.49g to 12.73%), a high content of volatile matter (33,32-37.45%) and high gross calorific values (7430-8880 kcal/kg). The mineral matter of the coal samples studied is made up of dolomite (〉909g), quartz, sphalerite, galena, pyrite and clay minerals. Major elements are positively cor- related with ash content suggesting an association with inorganic constituents. Based on statistical anal- yses, concentrations of trace elements such as Co (51.3 ×10^-6-152.9× 10^-6), Ba (368× 10^-6-3297.4×10^-6), Cr (65.5 ×10^-6-194.2 × 10^-6), Mo (5.6 × 10^-6-18.2× 10^-6), Hi (72.9 × 10^-6-152.9 × 10^-6) and V (245.5 × 10^-6-520 ×10^-6) are higher than world coal averages. However, low concentration of some vol- atile elements such as As, Hg and U are present in low concentrations of the various types of coal studied.
文摘Purpose: Trauma-related injuries are the leading cause of death worldwide. Some risk factors make trau- matic patients susceptible to infection. Furthermore, some mortality risk factors, including length of hos- pitalization and increasing age, were detected in non-traumatic infected patients. This study aimed to assess mortality risk factors among nosocomial infected traumatic patients in Rajaee trauma center, Shiraz, Iran. Methods: This prospective cohort study was conducted during a period of 2 years since April 2015 to March 2017 in Rajaee hospital, which is the center of emergency medical services for traumatic injuries in Shiraz, Iran. Centers for Disease Control and Prevention/National Healthcare Safety Network surveil- lance system criteria were applied to define 5 types of nosocomial infections. The variables analyzed as the risk factors of infection and mortality included sex, age, mechanism of injury, site of injury, injury severity score (ISS), surgical intervention, length of hospitalization, intensive care unit (ICU) admission, and type of pathogen. Then, the incidence of nosocomial infection and also risk factors of mortality in traumatic patients were evaluated. All data analyses were performed using the statistical package for social sciences, version 15 (SPSS Inc., Chicago) and p 〈 0.05 is considered to be statistically significant. Results: The incidence of nosocomial infection was 7.2% (p 〈 0.001). Pneumonia was the most common type of infection detected in our study. Infection led to a 7.8-fold increase in mortality of the traumatic patients (p 〈 O.001 ). Admission in intensive care units and old age were the main risk factors of mortality in infected traumatic patients. Old age, gunshot and motor vehicle accidents, trauma to extremities and abdomen, higher injury severity score, and prolonged hospitalization, made the traumatic patients more susceptible to infection.
基金supported by the National Natural Science Foundation of China (Grant No. 10972015)
文摘Using the concept of base forces as state variables,a new finite element method-the base force element method (BFEM) on complementary energy principle for linear elasticity problems is presented.Firstly,an explicit expression of compliance matrix for an element is derived through base forces by dyadic vectors.Then,the explicit control equations of finite element method of complementary energy principle are derived using Lagrange multiplier method.Thereafter,the base forces element procedure for linear elasticity is developed.Finally,several examples are analyzed to illustrate the reliability and accuracy of the formulation and the procedure.
基金supported by the National Hi-Tech Research and Development Program of China ("863" Project) (Grant No. 2012BAB02B04)
文摘Uncertainty analysis and risk analysis are two important areas of modern water resource management,in which accurate variance estimation is required.The traditional runoff model is established under the assumption that the variance is a constant or it changes with the seasons.However,hydrological processes in the real world are often heteroscedastic,which can be tested by McLeod-Li test and Engle Lagrange multiplier test.In such cases,the GARCH model of hydrological processes is established in this article.First,the seasonal factors in the sequence are removed.Second,the traditional ARMA model is established.Then,the GARCH model is used to correct the residual.At last,the daily runoff data in 1949-2001 of Yichang Hydrological Station is taken to be an example.The result shows that compared to the traditional ARMA model,the GARCH model has the ability to predict more accurate confidence intervals under the same confidence level.
基金Supported by the Isfahan University of Technology, Iranthe Technical University of Cartagena, Spain
文摘Limited information is available on the distribution and origin of palygorkite in soils developed on Tertiary sediments as the major soil parent materials in central Iran and other Middle Eastern countries. The objectives of this study were to determine the distribution and origin of palygorskite in soils developed on Tertiary sediments, and to identify the major soil properties that influence palygorskite distribution in the soils studied. Sixteen soil profiles developed on Paleocene, Eocene, Oligocene, Oligocene-Miocene, Miocene and Pliocene sediments were studied by X-ray diffraction analysis, transmission electron microscope, and scanning electron microscopy. Physicochemical characteristics of the soils and sediments including particle size distribution, pH, electrical conductivity, organic carbon, gypsum, carbonates, and soluble Si, Ca and Mg were determined. The principal component analysis was used to establish the relationships between palygorskite and the physicochemical characteristics of the soils studied. Results showed that clay fraction of all the soils in the study area was dominated by palygorskite. The highest amount of palygorskite was found in horizons where simultaneous accumulation of both carbonates and gypsum occurred. Limited amount of palygorskite was found in salic and calcic horizons. Palygorskite seemed to be of eolian origin in the surface horizon of all the soils. Using principal component analysis, the soluble Mg/Ca ratio, pH, soluble Si and gypsum contents were identified as the most important factors affecting the distribution and genesis of palygorskite in the soils studied. Results might suggest the neoformation of palygorskite by precipitation from solutions in which evaporation fluxes were very high. However, palygorskite in soils developed on Tertiary sediments in central Iran seems to be of both inherited and pedogenic origins.