英国自然历史博物馆(British Museum of Natural History)最早是大英博物馆的一个部,1963年完全独立出来,后来,又不断发展扩大。到目前为止该博物馆包括自然历史馆、动物馆和地质馆三部分。以前,该博物馆与世界上其他大多数博物馆一样,...英国自然历史博物馆(British Museum of Natural History)最早是大英博物馆的一个部,1963年完全独立出来,后来,又不断发展扩大。到目前为止该博物馆包括自然历史馆、动物馆和地质馆三部分。以前,该博物馆与世界上其他大多数博物馆一样,都是将展品摆在玻璃柜中。展开更多
Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of ...Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of the 20th century. The dawn of the 21st has brought forward great expectations in harnessing the power of totipotentcy in medicine. Through stem cell biology, it is possible to generate any parts of the human body by stem cell engineering. Considerable resources will be devoted to harness the untapped potentials of stem cells in the foreseeable future which may transform medicine as we know today. At the molecular level, totipotency has been linked to a singular transcription factor and its expression appears to define whether a cell should be totipotent. Named Oct4, it can activate or repress the expression of various genes. Curiously, very little is known about Oct4 beyond its ability to regulate gene expression. The mechanism by which Oct4 specifies totipotency remains entirely unresolved. In this review, we summarize the structure and function of Oct4 and address issues related to Oct4 function in maintaining totipotency or pluripotency of embryonic stem cells.展开更多
The present work shows the results of a pilot methodology, designed after a series of observations and documented from 2006, on the process of acquisition of Translation Competence （TC） of students of translation. T...The present work shows the results of a pilot methodology, designed after a series of observations and documented from 2006, on the process of acquisition of Translation Competence （TC） of students of translation. This method of analysis, appointed Previous Protocol to Translation or PPT, emerged as an option in search of teaching strategies of translation. This PPT has provided data not only on how novice translators acquire the translation competence, but it has been uncovered some independent variables that directly affect their development. There has been, in the four semesters analyzed in this work, a clear pattern that shows that an appropriate quality control to translate （and to carry out punctual terminology management） determines a better or worse quality of the final product （translations）; therefore, this reflects in a better translation competence in the novice students.展开更多
Aiming at the issue of yaw and rollover stability control for off-road vehicles with non-pneumatic mechanical elastic wheel(MEW),an integrated control system based on fuzzy differential braking is developed.By simplif...Aiming at the issue of yaw and rollover stability control for off-road vehicles with non-pneumatic mechanical elastic wheel(MEW),an integrated control system based on fuzzy differential braking is developed.By simplifying the structure of the MEW,a corresponding fitting brush tire model is constructed and its longitudinal and lateral tire force expressions are set up,respectively.Then,a nonlinear vehicle simulation model with MEW is established to validate the proposed control scheme based on Carsim.The designed yaw and rollover control system is a two-level structure with the upper additional moment controller,which utilizes a predictive load transfer ratio(PLTR)as the rollover index.In order to design the upper integrated control algorithm,fuzzy proportional-integral-derivative(PID)is adopted to coordinate the yaw and rollover control,simultaneously.And the lower control allocator realizes the additional moment to the vehicle by differential braking.Finally,a Carsim-simulink co-simulation model is constructed,and simulation results show that the integrated control system could improve the vehicle yaw and roll stability,and prevent rollover happening.展开更多
AIM:To test the Genval recommendations and the usefulness of a short trial of proton pump inhibitor(PPI) in the initial management and maintenance treatment of gastroesophageal reflux disease(GERD)patients. METHODS:Fi...AIM:To test the Genval recommendations and the usefulness of a short trial of proton pump inhibitor(PPI) in the initial management and maintenance treatment of gastroesophageal reflux disease(GERD)patients. METHODS:Five hundred and seventy seven patients with heartburn were recruited.After completing a psychometric tool to assess quality of life(PGWBI)and a previously validated GERD symptom questionnaire (QUID),patients were grouped into those with esophagitis(EE,n=306)or without mucosal damage (NERD,n=271)according to endoscopy results. The study started with a 2-wk period of high dose omeprazole(omeprazole test);patients responding to this PPI test entered an acute phase(3 mo)of treatment with any PPI at the standard dose.Finally,those patients with a favorable response to the standard PPI dose were maintained on a half PPI dose for a further 3-mo period. RESULTS:The test was positive in 519(89.9%)patients,with a greater response in EE patients(96.4%) compared with NERD patients(82.6%)(P=0.011). Both the percentage of completely asymptomatic patients,at 3 and 6 mo,and the reduction in heartburn intensity were significantly higher in the EE compared with NERD patients(P<0.01).Finally,the mean PGWBI score was significantly decreased before and increased after therapy in both subgroups when compared with the mean value in a reference Italian population. CONCLUSION:Our study confirms the validity of the Genval guidelines in the management of GERD patients. In addition,we observed that the overall response to PPI therapy is lower in NERD compared to EE patients.展开更多
文摘Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of the 20th century. The dawn of the 21st has brought forward great expectations in harnessing the power of totipotentcy in medicine. Through stem cell biology, it is possible to generate any parts of the human body by stem cell engineering. Considerable resources will be devoted to harness the untapped potentials of stem cells in the foreseeable future which may transform medicine as we know today. At the molecular level, totipotency has been linked to a singular transcription factor and its expression appears to define whether a cell should be totipotent. Named Oct4, it can activate or repress the expression of various genes. Curiously, very little is known about Oct4 beyond its ability to regulate gene expression. The mechanism by which Oct4 specifies totipotency remains entirely unresolved. In this review, we summarize the structure and function of Oct4 and address issues related to Oct4 function in maintaining totipotency or pluripotency of embryonic stem cells.
文摘The present work shows the results of a pilot methodology, designed after a series of observations and documented from 2006, on the process of acquisition of Translation Competence （TC） of students of translation. This method of analysis, appointed Previous Protocol to Translation or PPT, emerged as an option in search of teaching strategies of translation. This PPT has provided data not only on how novice translators acquire the translation competence, but it has been uncovered some independent variables that directly affect their development. There has been, in the four semesters analyzed in this work, a clear pattern that shows that an appropriate quality control to translate （and to carry out punctual terminology management） determines a better or worse quality of the final product （translations）; therefore, this reflects in a better translation competence in the novice students.
基金Project(11672127)supported by the National Natural Science Foundation of ChinaProject(NHAl3002)supported by the Major Exploration Project of the General Armaments Department of China+1 种基金Project(KYCX17_0240)supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province,ChinaProjects(NP2016412,NP2018403,NT2018002)supported by the Fundamental Research Funds for the Central Universities,China
文摘Aiming at the issue of yaw and rollover stability control for off-road vehicles with non-pneumatic mechanical elastic wheel(MEW),an integrated control system based on fuzzy differential braking is developed.By simplifying the structure of the MEW,a corresponding fitting brush tire model is constructed and its longitudinal and lateral tire force expressions are set up,respectively.Then,a nonlinear vehicle simulation model with MEW is established to validate the proposed control scheme based on Carsim.The designed yaw and rollover control system is a two-level structure with the upper additional moment controller,which utilizes a predictive load transfer ratio(PLTR)as the rollover index.In order to design the upper integrated control algorithm,fuzzy proportional-integral-derivative(PID)is adopted to coordinate the yaw and rollover control,simultaneously.And the lower control allocator realizes the additional moment to the vehicle by differential braking.Finally,a Carsim-simulink co-simulation model is constructed,and simulation results show that the integrated control system could improve the vehicle yaw and roll stability,and prevent rollover happening.
文摘AIM:To test the Genval recommendations and the usefulness of a short trial of proton pump inhibitor(PPI) in the initial management and maintenance treatment of gastroesophageal reflux disease(GERD)patients. METHODS:Five hundred and seventy seven patients with heartburn were recruited.After completing a psychometric tool to assess quality of life(PGWBI)and a previously validated GERD symptom questionnaire (QUID),patients were grouped into those with esophagitis(EE,n=306)or without mucosal damage (NERD,n=271)according to endoscopy results. The study started with a 2-wk period of high dose omeprazole(omeprazole test);patients responding to this PPI test entered an acute phase(3 mo)of treatment with any PPI at the standard dose.Finally,those patients with a favorable response to the standard PPI dose were maintained on a half PPI dose for a further 3-mo period. RESULTS:The test was positive in 519(89.9%)patients,with a greater response in EE patients(96.4%) compared with NERD patients(82.6%)(P=0.011). Both the percentage of completely asymptomatic patients,at 3 and 6 mo,and the reduction in heartburn intensity were significantly higher in the EE compared with NERD patients(P<0.01).Finally,the mean PGWBI score was significantly decreased before and increased after therapy in both subgroups when compared with the mean value in a reference Italian population. CONCLUSION:Our study confirms the validity of the Genval guidelines in the management of GERD patients. In addition,we observed that the overall response to PPI therapy is lower in NERD compared to EE patients.
