The freeze-thaw cycling process considerably changes the composition, structure, and properties of soils. Since the grain size is the most important factor in determining soil characteristics, our current research pri...The freeze-thaw cycling process considerably changes the composition, structure, and properties of soils. Since the grain size is the most important factor in determining soil characteristics, our current research primarily aims to investigate dynamic changes of the soil fraction when exposed to freeze-thaw conditions. We observed two series of Moscow morainic clayey specimens （gQⅡm）： （Ⅰ） the original series, and （Ⅱ） the remolded series. We subjected each series of soil specimens to different frequencies of freeze-thaw cycles （3, 6, 20, and 40 cycles）, and we used granulometric tests to analyze both series before and after exposure to freeze-thaw conditions. As a result of our experiments, the granulometric compositions tended to be distributed evenly after 40 freeze-thaw processes （i.e., content of fraction for 0.1-0.05 mm was increased after 40 freeze-thaw cycles） because the division of coarse grains and the aggregation of fine grains were synchronized during the freeze-thaw process. The soil grains in both series changed bi-directionally. In the original series, changes of the sand grains were conjugated with the clay grains, and in the remolded series, changes of the sand grains were conjugated with the silt grains, because potential energy difference caused the division and aggregation processes to relate to the counteraction process. The even distribution of soil grain size indicated the state of equilibrium or balance. The granulometric compositions were altered the most during the sixth freeze-thaw cycle, because the coefficient of the intensity variation of the grain fineness （Kvar） had its maximum value at that time.展开更多
Enteric viruses are the most common cause of acute gastroenteritis （AGE） in young children and a significant public health problem globally. Hospital admissions of children under 5 years of age with diarrhea are pri...Enteric viruses are the most common cause of acute gastroenteritis （AGE） in young children and a significant public health problem globally. Hospital admissions of children under 5 years of age with diarrhea are primarily associated with group A rotavirus （RVA） infection. In this retrospective study, the population structure of viruses linked to AGE etiology in young children hospitalized with AGE in Moscow was evaluated, and molecular characterization of RYA strains was performed. Fecal specimens were collected from children under 5 years old hospitalized with AGE between 2009 and 2014 in Moscow, Russia. Multiplex real-time reverse transcription PCR was used to detect enteric viruses and for G/[P]-genotyping of isolated RVAs. Sequencing of RVA VP7 and VP4 cDNA fragments was used to validate the data obtained by PCR- genotyping. The main causes for hospitalization of children with AGE were RVA （40.1%）, followed by noroviruses （11.4%）, while adenoviruses, astroviruses, sapoviruses, enteroviruses, and orthoreoviruses were detected in 4.7%, 1.9%, 1.4%, 1.2%, and 0.2% of samples tested, respectively. Nosocomial infections, predominantly associated with RVAs and noroviruses, were detected in 24.8% of cases and occurred significantly more frequently in younger infants. The predominant RVA genotype was G4P[8], detected in 38.7% of RVA-positive cases, whereas genotypes G1P[8], G9P[8], G3P[8], and G2P[4] were found in 11.8%, 6.6%, 4.2%, and 3.3% of cases, respectively. Together, the presence of circulating RVA strains with rare VP7 and VP4 gene variants （G6 and P[9]） highlights the need to conduct continuous epidemiological monitoring of RVA infection.展开更多
One decade ago,it was at the Moscow State Institute of International Relations that Xi Jinping first put forward the concept of a community with a shared future for humanity in his first overseas trip as President of ...One decade ago,it was at the Moscow State Institute of International Relations that Xi Jinping first put forward the concept of a community with a shared future for humanity in his first overseas trip as President of China.展开更多
基金supported in part by the National Natural Science Foundation of China(No.41301070)the West Light Program for Talent Cultivation of Chinese Academy of Sciencesthe project sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,which granted to Dr.Ze Zhang
文摘The freeze-thaw cycling process considerably changes the composition, structure, and properties of soils. Since the grain size is the most important factor in determining soil characteristics, our current research primarily aims to investigate dynamic changes of the soil fraction when exposed to freeze-thaw conditions. We observed two series of Moscow morainic clayey specimens （gQⅡm）： （Ⅰ） the original series, and （Ⅱ） the remolded series. We subjected each series of soil specimens to different frequencies of freeze-thaw cycles （3, 6, 20, and 40 cycles）, and we used granulometric tests to analyze both series before and after exposure to freeze-thaw conditions. As a result of our experiments, the granulometric compositions tended to be distributed evenly after 40 freeze-thaw processes （i.e., content of fraction for 0.1-0.05 mm was increased after 40 freeze-thaw cycles） because the division of coarse grains and the aggregation of fine grains were synchronized during the freeze-thaw process. The soil grains in both series changed bi-directionally. In the original series, changes of the sand grains were conjugated with the clay grains, and in the remolded series, changes of the sand grains were conjugated with the silt grains, because potential energy difference caused the division and aggregation processes to relate to the counteraction process. The even distribution of soil grain size indicated the state of equilibrium or balance. The granulometric compositions were altered the most during the sixth freeze-thaw cycle, because the coefficient of the intensity variation of the grain fineness （Kvar） had its maximum value at that time.
基金RVA G/[P]-genotypes was at the expense of the Russian Science Foundation(Grant No.16-15-10332)
文摘Enteric viruses are the most common cause of acute gastroenteritis （AGE） in young children and a significant public health problem globally. Hospital admissions of children under 5 years of age with diarrhea are primarily associated with group A rotavirus （RVA） infection. In this retrospective study, the population structure of viruses linked to AGE etiology in young children hospitalized with AGE in Moscow was evaluated, and molecular characterization of RYA strains was performed. Fecal specimens were collected from children under 5 years old hospitalized with AGE between 2009 and 2014 in Moscow, Russia. Multiplex real-time reverse transcription PCR was used to detect enteric viruses and for G/[P]-genotyping of isolated RVAs. Sequencing of RVA VP7 and VP4 cDNA fragments was used to validate the data obtained by PCR- genotyping. The main causes for hospitalization of children with AGE were RVA （40.1%）, followed by noroviruses （11.4%）, while adenoviruses, astroviruses, sapoviruses, enteroviruses, and orthoreoviruses were detected in 4.7%, 1.9%, 1.4%, 1.2%, and 0.2% of samples tested, respectively. Nosocomial infections, predominantly associated with RVAs and noroviruses, were detected in 24.8% of cases and occurred significantly more frequently in younger infants. The predominant RVA genotype was G4P[8], detected in 38.7% of RVA-positive cases, whereas genotypes G1P[8], G9P[8], G3P[8], and G2P[4] were found in 11.8%, 6.6%, 4.2%, and 3.3% of cases, respectively. Together, the presence of circulating RVA strains with rare VP7 and VP4 gene variants （G6 and P[9]） highlights the need to conduct continuous epidemiological monitoring of RVA infection.
文摘One decade ago,it was at the Moscow State Institute of International Relations that Xi Jinping first put forward the concept of a community with a shared future for humanity in his first overseas trip as President of China.
