Based on historical data and field investigation, some major fluxes and reserves of carbon were estimated, and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin Rive...Based on historical data and field investigation, some major fluxes and reserves of carbon were estimated, and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin River basin of Inner Mongolia. Major results were reported as follows: 1) Annual average carbon input from above-ground biomass production was 79.8 g C(.)m(-2.)a(-1), and from root biomass to 30 cm. depth averaged 311.9 g C(.)m(-2.)a(-1). The summed mean annual carbon input of shoot and root materials in the study site was approximately 391.7 g C(.)m(-2.)a(-1). 2) The annual amount of above-ground biomass consumed by insects averaged 14.7 g C(.)m(-2.)a(-1), and the carbon output by leaching or light-chemical oxidation was 3.2 g C(.)m(-2.)a(-1) The annual evolution rate of CO2 from net soil respiration averaged 346.9 g C(.)m(-2.)a(-1), and the summed mean annual output was approximately 364.8 g C(.)m(-2.)a(-1). 3) A mature, steady-state system could be assumed for the community for which growth and decay were approximately in balance, with a net carbon accumulation of about 26.9 g C(.)m(-2.)a(-1). Based on the soil organic carbon density of the field, the turnover Irate of soil carbon in 0 - 30 cm depth was calculated to be 6.2%, with a turnover time of 16 years.展开更多
Duplication cyst of the stomach with a pseudostratifie columnar ciliated epithelium is extremely rare.We de scribe two cases of these cysts,with emphasis on the immunophenotype and embryogenesis.The first patien was a...Duplication cyst of the stomach with a pseudostratifie columnar ciliated epithelium is extremely rare.We de scribe two cases of these cysts,with emphasis on the immunophenotype and embryogenesis.The first patien was a 29-year-old man who presented with crampin abdominal pain in his left lower quadrant.The secon patient was a 26-year-old woman who had a history over several years,of chronic epigastric abdominal pai radiating to her back.Both lesions were surgically re moved.They showed the same histomorphology.Th cysts were lined by a pseudostratified respiratory ep thelium with ciliated cells.The first cyst was connecte to the stomach,while the second cyst was not connect ed.Both cysts expressed thyroid transcription factor(TTF-1) and surfactant.In this report,we explore th possible embryogenesis of these lesions in the light o TTF-1 and surfactant expression.展开更多
AIM:Elevation of alanine aminotransferase (ALT) level is commonly seen among patients suffering from severe acute respiratory syndrome (SARS). We report the progression and clinical significance of liver derangement i...AIM:Elevation of alanine aminotransferase (ALT) level is commonly seen among patients suffering from severe acute respiratory syndrome (SARS). We report the progression and clinical significance of liver derangement in a large cohort of SARS patient. METHODS: Serial assay of serum ALT was followed in patients who fulfilled the WHO criteria of SARS. Those with elevated ALT were compared with those with normal liver functions for clinical outcome. Serology for hepatitis B virus (HBV) infection was checked. Adverse outcomes were defined as oxygen desaturation, need of intensive care unit (ICU) and mechanical ventilation and death. RESULTS: Two hundred and ninety-four patients were included in this study. Seventy (24%) patients had elevated serum ALT on admission and 204 (69%) patients had elevated ALT during the subsequent course of illness. Using peak ALT >5xULN as a cut-off and after adjusting for potential confounding factors, the odds ratio of peak ALT >5x ULN for oxygen desaturation was 3.24 (95%CI 1.23-8.59, P= 0.018), ICU care was 3.70 (95%CI 1.38-9.89, P= 0.009), mechanical ventilation was 6.64 (95%CI 2.22-19.81, P = 0.001) and death was 7.34 (95%CI 2.28-24.89, P= 0.001). Ninety-three percent of the survived patients had ALT levels normalized or were on the improving trend during follow-up. Chronic hepatitis B was not associated with worse clinical outcomes. CONCLUSION: Reactive hepatitis is a common complication of SARS-coronavirus infection. Those patients with severe hepatitis had worse clinical outcome.展开更多
The dynamics of different kinds of discrete breathers in three types of one-dimensionai monatomic chains with on-site and inter-site potentiais are investigated. The existence and evolution of symmetric breather, anti...The dynamics of different kinds of discrete breathers in three types of one-dimensionai monatomic chains with on-site and inter-site potentiais are investigated. The existence and evolution of symmetric breather, antisymmetric breather, and multibreather in one-dimensionai models are proved by using rotating wave approximation, local anharmonic approximation, and the numerical method. The linear stability of these breathers is investigated by using Lyapunov stable anaiysis. The localization and stability of breathers in three types of models correlate closely to the system nonlinear parameter β.展开更多
The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain rea...The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain reaction （PCR） assay, along with the incidence and severity of morbidity, mortality, and gross lesions. ARV RNA was detected in cloacal swabs in both bird groups from the first day throughout the 21 days experiment. Commercial broiler chickens, which had high maternal antibodies against ARV, showed minimum clinical signs, gross lesions, and lower numbers of birds with viral RNA excretion, whereas specific pathogen free （SPF） broiler chickens, which did not have antibody against ARVs, had 30% mortality, more severe signs, and higher numbers of birds excreting viral RNA. The highest peak of SPF birds excreting viral RNA occurred during the time of maximum mortality. The protective effect of maternal antibody on ARV pathogenesis in broiler chickens correlated with the detection of ARV RNA using the real-time RT-PCR.展开更多
A general and efficient method is presented in this paper for studying the effects of unbalance on the breathing mechanism of crack.Based on 3D finite element models combined with a nonlinear contact approach for crac...A general and efficient method is presented in this paper for studying the effects of unbalance on the breathing mechanism of crack.Based on 3D finite element models combined with a nonlinear contact approach for crack modeling, the method is free from theassumption of weight-dominance and can be used to gain deep insights into the breathing mechanism of crack. In order to greatlyreduce the computational time, a complex free-interface component mode synthesis (CMS) method is employed to reduce theorder of the model. Based on the proposed method, the effects of unbalance on the breathing mechanism of crack are discussed.Numerical results show that the unbalance can lead to significant changes in the breathing of crack, even when the unbalance force is about an order of magnitude smaller than the self-weight. Moreover, the level and orientation of the unbalance have also remarkable effects on the breathing behaviors of crack. Besides, a new universal non-steady breathing phenomenon of crack is firstly found in this paper, which denotes that the breathing speed of a crack is fluctuated over one revolution when there exists residual unbalance in the cracked rotor.展开更多
A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighbo...A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighboring area Hangzhou City in Zhejiang Province.In this study,epidemiologic,clinical,and virological data from three patients in Hangzhou who were confirmed to be infected by the novel H7N9 influenza A virus were collected and analyzed.Human respiratory specimens and chicken feces from a contacted free market were tested for influenza virus by real-time reverse transcription PCR(RT-PCR) and sequencing.The clinical features of the three cases were similar featured with high fever and severe respiratory symptoms;however,only one of the patients died.A certain degree of diversity was observed among the three Hangzhou viruses sequenced from human samples compared with other reported H7N9 influenza A viruses.The sequences of the novel avian-origin H7N9 influenza viruses from Hangzhou City contained important amino acid substitutions related to human adaptation.One of the Hangzhou viruses had gained a novel amino acid substitution(Q226I) in the receptor binding region of hemagglutinin.More importantly,the virus sequenced from the chicken feces had a 627E substitution in the PB2 protein instead of the mammalian-adapted 627K substitution that was found in the PB2 proteins from the Hangzhou viruses from the three patients.Therefore,the newly-emerging H7N9 virus might be under adaptation pressure that will help it "jump" from avian to human hosts.The significance of these substitutions needs further exploration,with both laboratory experiments and extensive field surveillance.展开更多
文摘Based on historical data and field investigation, some major fluxes and reserves of carbon were estimated, and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin River basin of Inner Mongolia. Major results were reported as follows: 1) Annual average carbon input from above-ground biomass production was 79.8 g C(.)m(-2.)a(-1), and from root biomass to 30 cm. depth averaged 311.9 g C(.)m(-2.)a(-1). The summed mean annual carbon input of shoot and root materials in the study site was approximately 391.7 g C(.)m(-2.)a(-1). 2) The annual amount of above-ground biomass consumed by insects averaged 14.7 g C(.)m(-2.)a(-1), and the carbon output by leaching or light-chemical oxidation was 3.2 g C(.)m(-2.)a(-1) The annual evolution rate of CO2 from net soil respiration averaged 346.9 g C(.)m(-2.)a(-1), and the summed mean annual output was approximately 364.8 g C(.)m(-2.)a(-1). 3) A mature, steady-state system could be assumed for the community for which growth and decay were approximately in balance, with a net carbon accumulation of about 26.9 g C(.)m(-2.)a(-1). Based on the soil organic carbon density of the field, the turnover Irate of soil carbon in 0 - 30 cm depth was calculated to be 6.2%, with a turnover time of 16 years.
文摘Duplication cyst of the stomach with a pseudostratifie columnar ciliated epithelium is extremely rare.We de scribe two cases of these cysts,with emphasis on the immunophenotype and embryogenesis.The first patien was a 29-year-old man who presented with crampin abdominal pain in his left lower quadrant.The secon patient was a 26-year-old woman who had a history over several years,of chronic epigastric abdominal pai radiating to her back.Both lesions were surgically re moved.They showed the same histomorphology.Th cysts were lined by a pseudostratified respiratory ep thelium with ciliated cells.The first cyst was connecte to the stomach,while the second cyst was not connect ed.Both cysts expressed thyroid transcription factor(TTF-1) and surfactant.In this report,we explore th possible embryogenesis of these lesions in the light o TTF-1 and surfactant expression.
文摘AIM:Elevation of alanine aminotransferase (ALT) level is commonly seen among patients suffering from severe acute respiratory syndrome (SARS). We report the progression and clinical significance of liver derangement in a large cohort of SARS patient. METHODS: Serial assay of serum ALT was followed in patients who fulfilled the WHO criteria of SARS. Those with elevated ALT were compared with those with normal liver functions for clinical outcome. Serology for hepatitis B virus (HBV) infection was checked. Adverse outcomes were defined as oxygen desaturation, need of intensive care unit (ICU) and mechanical ventilation and death. RESULTS: Two hundred and ninety-four patients were included in this study. Seventy (24%) patients had elevated serum ALT on admission and 204 (69%) patients had elevated ALT during the subsequent course of illness. Using peak ALT >5xULN as a cut-off and after adjusting for potential confounding factors, the odds ratio of peak ALT >5x ULN for oxygen desaturation was 3.24 (95%CI 1.23-8.59, P= 0.018), ICU care was 3.70 (95%CI 1.38-9.89, P= 0.009), mechanical ventilation was 6.64 (95%CI 2.22-19.81, P = 0.001) and death was 7.34 (95%CI 2.28-24.89, P= 0.001). Ninety-three percent of the survived patients had ALT levels normalized or were on the improving trend during follow-up. Chronic hepatitis B was not associated with worse clinical outcomes. CONCLUSION: Reactive hepatitis is a common complication of SARS-coronavirus infection. Those patients with severe hepatitis had worse clinical outcome.
基金Supported by the National Natural Science Foundation of China under Grant No.1057411 the Foundation for Researching Group by Beijing Normal University
文摘The dynamics of different kinds of discrete breathers in three types of one-dimensionai monatomic chains with on-site and inter-site potentiais are investigated. The existence and evolution of symmetric breather, antisymmetric breather, and multibreather in one-dimensionai models are proved by using rotating wave approximation, local anharmonic approximation, and the numerical method. The linear stability of these breathers is investigated by using Lyapunov stable anaiysis. The localization and stability of breathers in three types of models correlate closely to the system nonlinear parameter β.
文摘The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain reaction （PCR） assay, along with the incidence and severity of morbidity, mortality, and gross lesions. ARV RNA was detected in cloacal swabs in both bird groups from the first day throughout the 21 days experiment. Commercial broiler chickens, which had high maternal antibodies against ARV, showed minimum clinical signs, gross lesions, and lower numbers of birds with viral RNA excretion, whereas specific pathogen free （SPF） broiler chickens, which did not have antibody against ARVs, had 30% mortality, more severe signs, and higher numbers of birds excreting viral RNA. The highest peak of SPF birds excreting viral RNA occurred during the time of maximum mortality. The protective effect of maternal antibody on ARV pathogenesis in broiler chickens correlated with the detection of ARV RNA using the real-time RT-PCR.
基金supported by the Project of National Natural Science Foundation of China for Innovation Research Group (Grant No. 51421004)the National Natural Science Foundation of China (Grant No. 51275384)China Postdoctoral Science Foundation (Grant No. 2014M560765)
文摘A general and efficient method is presented in this paper for studying the effects of unbalance on the breathing mechanism of crack.Based on 3D finite element models combined with a nonlinear contact approach for crack modeling, the method is free from theassumption of weight-dominance and can be used to gain deep insights into the breathing mechanism of crack. In order to greatlyreduce the computational time, a complex free-interface component mode synthesis (CMS) method is employed to reduce theorder of the model. Based on the proposed method, the effects of unbalance on the breathing mechanism of crack are discussed.Numerical results show that the unbalance can lead to significant changes in the breathing of crack, even when the unbalance force is about an order of magnitude smaller than the self-weight. Moreover, the level and orientation of the unbalance have also remarkable effects on the breathing behaviors of crack. Besides, a new universal non-steady breathing phenomenon of crack is firstly found in this paper, which denotes that the breathing speed of a crack is fluctuated over one revolution when there exists residual unbalance in the cracked rotor.
基金supported by the Hangzhou Key Medicine Discipline Fund for Public Health Laboratory sponsored by the Hangzhou government,National Basic Research Program of China (2010CB530303,2011-CB504703)an intramural special grant for influenza virus research from Chinese Academy of Sciences (KSZD-EW-Z-002)
文摘A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai,China.This virus has also been identified in cases of infection in the neighboring area Hangzhou City in Zhejiang Province.In this study,epidemiologic,clinical,and virological data from three patients in Hangzhou who were confirmed to be infected by the novel H7N9 influenza A virus were collected and analyzed.Human respiratory specimens and chicken feces from a contacted free market were tested for influenza virus by real-time reverse transcription PCR(RT-PCR) and sequencing.The clinical features of the three cases were similar featured with high fever and severe respiratory symptoms;however,only one of the patients died.A certain degree of diversity was observed among the three Hangzhou viruses sequenced from human samples compared with other reported H7N9 influenza A viruses.The sequences of the novel avian-origin H7N9 influenza viruses from Hangzhou City contained important amino acid substitutions related to human adaptation.One of the Hangzhou viruses had gained a novel amino acid substitution(Q226I) in the receptor binding region of hemagglutinin.More importantly,the virus sequenced from the chicken feces had a 627E substitution in the PB2 protein instead of the mammalian-adapted 627K substitution that was found in the PB2 proteins from the Hangzhou viruses from the three patients.Therefore,the newly-emerging H7N9 virus might be under adaptation pressure that will help it "jump" from avian to human hosts.The significance of these substitutions needs further exploration,with both laboratory experiments and extensive field surveillance.
