Many patients with spinal injures are confined to wheelchairs, leading to a sedentary lifestyle with secondary pathologies and increased dependence on a carer. Increasing evidence has shown that locomotor training red...Many patients with spinal injures are confined to wheelchairs, leading to a sedentary lifestyle with secondary pathologies and increased dependence on a carer. Increasing evidence has shown that locomotor training reduces the incidence of these secondary pathologies, but the physical effort involved in this training is such that there is poor compliance. This paper reports on the design and control of a new ＂human friendly＂ orthosis （exoskeleton）, powered by high power pneumatic Muscle Actuators （pMAs）. The combination of a highly compliant actuation system, with an intelligent embedded control mechanism which senses hip, knee, and ankle positions, velocity, acceleration and force, produces powerful yet inherently safe operation for paraplegic patients. This paper analyzes the motion of ankle, knee, and hip joints under zero loading, and loads which simulate human limb mass, showing that the use of ＂soft＂ actuators can provide a smooth user friendly motion. The application of this technology will greatly improve the rehabilitative protocols for paraplegic patients.展开更多
In the early 1980s, evidence that crustal rocks had reached temperatures 〉1000 ℃ at normal lower crustal pressures while others had followed low thermal gradients to record pressures characteristic of mantle conditi...In the early 1980s, evidence that crustal rocks had reached temperatures 〉1000 ℃ at normal lower crustal pressures while others had followed low thermal gradients to record pressures characteristic of mantle conditions began to appear in the literature, and the importance of melting in the tectonic evolution of orogens and metamorphic-metasomatic reworking of the lithospheric mantle was realized. In parallel, new developments in instrumentation, the expansion of in situ analysis of geological ma- terials and increases in computing power opened up new fields of investigation. The robust quantifi- cation of pressure （P）, temperature （T） and time （t） that followed these advances has provided reliable data to benchmark geodynamic models and to investigate secular change in the thermal state of the lithosphere as registered by metamorphism through time. As a result, the last 30 years have seen sig- nificant progress in our understanding of lithospheric evolution, particularly as it relates to Precambrian geodynamics.展开更多
Supercritical fluid and granitic melt are commonly generated as pressure decreases during exhumation of deeply subducted continental crust from mantle depths,promoting crust–mantle interaction,changing the rheology o...Supercritical fluid and granitic melt are commonly generated as pressure decreases during exhumation of deeply subducted continental crust from mantle depths,promoting crust–mantle interaction,changing the rheology of material along much of the subduction channel and,in a feedback loop,facilitating ongoing exhumation.However.展开更多
Over 200 humans have been treated with myoblast transplantation for heart muscle repair since June 2000. Bioheart sponsored percutaneous delivery studies began in May 2001 in Europe. Approximately one third of the pat...Over 200 humans have been treated with myoblast transplantation for heart muscle repair since June 2000. Bioheart sponsored percutaneous delivery studies began in May 2001 in Europe. Approximately one third of the patients have exhibited substantial improvement in left ventricular ejection fraction (LVEF) of over 30% and two heart failure class improvements. Over 80% of the patients have exhibited one heart failure class improvement with moderate improvement of LVEF. Clinical trials seem to demonstrate a marked reduction in emergency hospitalizations in myoblast treated patients. Many years of careful studies have lead to randomized controlled studies that are enrolling patients now at numerous centers worldwide. A firm conclusion on the safety and efficacy of myoblast transplantation cannot be determined until these randomized studies are completed. Final results from randomized controlled studies should be available soon.展开更多
Introduction: Acute viral hepatitis is a relatively common infection resulting in hospital attendance after foreign travel. Travellers and doctors are generally aware of hepatitis A and the fact that safe and effectiv...Introduction: Acute viral hepatitis is a relatively common infection resulting in hospital attendance after foreign travel. Travellers and doctors are generally aware of hepatitis A and the fact that safe and effective immunisation is available. In contrast, there is no widely available vaccine for hepatitis E and most physicians’ experience with this condition is limited. Over the last few years, the number of cases of hepatitis E has increased. Methods: We examined the prevalence of hepatitis A and E among patients presenting to the Hospital for Tropical Diseases between 2000 and 2009. Travel history, demographics and laboratory parameters of these patients were compared. Results: The annual incidence of hepatitis A remained static, while that of hepatitis E increased from 1 to 4. Hepatitis E was associated with older age, travel to the Indian sub-continent (ISC), and visiting friends and relatives (VFR). Peak ALT was similar between patients with hepatitis A or E, but as many as a third of those with hepatitis E developed a prolonged INR, compared to 11% of those with hepatitis A. In addition, patients with hepatitis E had a longer hospital admission by a median of 3 days. Conclusion: Hepatitis E is now the commonest cause of faeco-oral viral hepatitis at this centre, and is associated with laboratory features suggestive of more severe liver damage and longer hospital stay.展开更多
The complex genetic architecture of quality traits has hindered efforts to modify seed nutrients in soybean. Genome-wide association studies were conducted for seed composition, including protein, oil, fatty acids, an...The complex genetic architecture of quality traits has hindered efforts to modify seed nutrients in soybean. Genome-wide association studies were conducted for seed composition, including protein, oil, fatty acids, and amino acids, using 313 diverse soybean germplasm accessions genotyped with a high-density SNP array. A total of 87 chromosomal regions were identified to be associated with seed composition, explain- ing 8%-89% of genetic variances. The candidate genes GmSAT1, AK-HSDH, SACPD-C, and FAD3A of known function, and putative MtN21 nodulin, FATB, and steroid-5-^-reductase involved in N2 fixation, amino acid biosynthesis, and fatty acid metabolism were found at the major-effect loci. Further analysis of additional germplasm accessions indicated that these major-effect loci had been subjected to domes- tication or modern breeding selection, and the allelic variants and distributions were relevant to geographic regions. We also revealed that amino acid concentrations related to seed weight and to total protein had a different genetic basis. This helps uncover the in-depth genetic mechanism of the intricate relationships among the seed compounds. Thus, our study not only provides valuable genes and markers for soybean nutrient improvement, both quantitatively and qualitatively, but also offers insights into the alteration of soybean quality during domestication and breeding.展开更多
Few-layer graphene (FLG) has recently been intensively investigated for its variable electronic properties, which are defined by a local atomic arrangement. While the most natural arrangement of layers in FLG is ABA (...Few-layer graphene (FLG) has recently been intensively investigated for its variable electronic properties, which are defined by a local atomic arrangement. While the most natural arrangement of layers in FLG is ABA (Bernal) stacking, a metastable ABC (rhombohedral) stacking, characterized by a relatively high-energy barrier, can also occur. When both types of stacking occur in one FLG device, the arrangement results in an in-plane heterostructure with a domain wall (DW). In this paper, we present two approaches to demonstrate that the ABC stacking in FLG can be controllably and locally turned into the ABA stacking. In the first approach, we introduced Joule heating, and the transition was characterized by 2D peak Raman spectra at a submicron spatial resolution. The transition was initiated in a small region, and then the DW was controllably shifted until the entire device became ABA stacked. In the second approach, the transition was achieved by illuminating the ABC region with a train of 790-nm-wavelength laser pulses, and the transition was visualized by transmission electron microscopy in both diffraction and dark-field imaging modes. Further, using this approach, the DW was visualized at a nanoscale spatial resolution in the dark-field imaging mode.展开更多
When it comes to convection,what goes up must come down.Or is it,what goes down must come up?The truth is,it depends.Although convection must be mass-balanced,there is no reason that it must be force-balanced:the posi...When it comes to convection,what goes up must come down.Or is it,what goes down must come up?The truth is,it depends.Although convection must be mass-balanced,there is no reason that it must be force-balanced:the positive and negative buoyancy forces driving convection up and down,respectively,do not necessarily need to be balanced.The balance,or imbalance,all depends on the top and bottom boundary layers.展开更多
文摘Many patients with spinal injures are confined to wheelchairs, leading to a sedentary lifestyle with secondary pathologies and increased dependence on a carer. Increasing evidence has shown that locomotor training reduces the incidence of these secondary pathologies, but the physical effort involved in this training is such that there is poor compliance. This paper reports on the design and control of a new ＂human friendly＂ orthosis （exoskeleton）, powered by high power pneumatic Muscle Actuators （pMAs）. The combination of a highly compliant actuation system, with an intelligent embedded control mechanism which senses hip, knee, and ankle positions, velocity, acceleration and force, produces powerful yet inherently safe operation for paraplegic patients. This paper analyzes the motion of ankle, knee, and hip joints under zero loading, and loads which simulate human limb mass, showing that the use of ＂soft＂ actuators can provide a smooth user friendly motion. The application of this technology will greatly improve the rehabilitative protocols for paraplegic patients.
基金support from the International Precambrian Research Centre of China
文摘In the early 1980s, evidence that crustal rocks had reached temperatures 〉1000 ℃ at normal lower crustal pressures while others had followed low thermal gradients to record pressures characteristic of mantle conditions began to appear in the literature, and the importance of melting in the tectonic evolution of orogens and metamorphic-metasomatic reworking of the lithospheric mantle was realized. In parallel, new developments in instrumentation, the expansion of in situ analysis of geological ma- terials and increases in computing power opened up new fields of investigation. The robust quantifi- cation of pressure （P）, temperature （T） and time （t） that followed these advances has provided reliable data to benchmark geodynamic models and to investigate secular change in the thermal state of the lithosphere as registered by metamorphism through time. As a result, the last 30 years have seen sig- nificant progress in our understanding of lithospheric evolution, particularly as it relates to Precambrian geodynamics.
基金supported by the National Natural Science Foundation of China(42072228,41572182,41272225)the project from Chinese Ministry of Education(BP071922)
文摘Supercritical fluid and granitic melt are commonly generated as pressure decreases during exhumation of deeply subducted continental crust from mantle depths,promoting crust–mantle interaction,changing the rheology of material along much of the subduction channel and,in a feedback loop,facilitating ongoing exhumation.However.
文摘Over 200 humans have been treated with myoblast transplantation for heart muscle repair since June 2000. Bioheart sponsored percutaneous delivery studies began in May 2001 in Europe. Approximately one third of the patients have exhibited substantial improvement in left ventricular ejection fraction (LVEF) of over 30% and two heart failure class improvements. Over 80% of the patients have exhibited one heart failure class improvement with moderate improvement of LVEF. Clinical trials seem to demonstrate a marked reduction in emergency hospitalizations in myoblast treated patients. Many years of careful studies have lead to randomized controlled studies that are enrolling patients now at numerous centers worldwide. A firm conclusion on the safety and efficacy of myoblast transplantation cannot be determined until these randomized studies are completed. Final results from randomized controlled studies should be available soon.
文摘Introduction: Acute viral hepatitis is a relatively common infection resulting in hospital attendance after foreign travel. Travellers and doctors are generally aware of hepatitis A and the fact that safe and effective immunisation is available. In contrast, there is no widely available vaccine for hepatitis E and most physicians’ experience with this condition is limited. Over the last few years, the number of cases of hepatitis E has increased. Methods: We examined the prevalence of hepatitis A and E among patients presenting to the Hospital for Tropical Diseases between 2000 and 2009. Travel history, demographics and laboratory parameters of these patients were compared. Results: The annual incidence of hepatitis A remained static, while that of hepatitis E increased from 1 to 4. Hepatitis E was associated with older age, travel to the Indian sub-continent (ISC), and visiting friends and relatives (VFR). Peak ALT was similar between patients with hepatitis A or E, but as many as a third of those with hepatitis E developed a prolonged INR, compared to 11% of those with hepatitis A. In addition, patients with hepatitis E had a longer hospital admission by a median of 3 days. Conclusion: Hepatitis E is now the commonest cause of faeco-oral viral hepatitis at this centre, and is associated with laboratory features suggestive of more severe liver damage and longer hospital stay.
文摘The complex genetic architecture of quality traits has hindered efforts to modify seed nutrients in soybean. Genome-wide association studies were conducted for seed composition, including protein, oil, fatty acids, and amino acids, using 313 diverse soybean germplasm accessions genotyped with a high-density SNP array. A total of 87 chromosomal regions were identified to be associated with seed composition, explain- ing 8%-89% of genetic variances. The candidate genes GmSAT1, AK-HSDH, SACPD-C, and FAD3A of known function, and putative MtN21 nodulin, FATB, and steroid-5-^-reductase involved in N2 fixation, amino acid biosynthesis, and fatty acid metabolism were found at the major-effect loci. Further analysis of additional germplasm accessions indicated that these major-effect loci had been subjected to domes- tication or modern breeding selection, and the allelic variants and distributions were relevant to geographic regions. We also revealed that amino acid concentrations related to seed weight and to total protein had a different genetic basis. This helps uncover the in-depth genetic mechanism of the intricate relationships among the seed compounds. Thus, our study not only provides valuable genes and markers for soybean nutrient improvement, both quantitatively and qualitatively, but also offers insights into the alteration of soybean quality during domestication and breeding.
文摘Few-layer graphene (FLG) has recently been intensively investigated for its variable electronic properties, which are defined by a local atomic arrangement. While the most natural arrangement of layers in FLG is ABA (Bernal) stacking, a metastable ABC (rhombohedral) stacking, characterized by a relatively high-energy barrier, can also occur. When both types of stacking occur in one FLG device, the arrangement results in an in-plane heterostructure with a domain wall (DW). In this paper, we present two approaches to demonstrate that the ABC stacking in FLG can be controllably and locally turned into the ABA stacking. In the first approach, we introduced Joule heating, and the transition was characterized by 2D peak Raman spectra at a submicron spatial resolution. The transition was initiated in a small region, and then the DW was controllably shifted until the entire device became ABA stacked. In the second approach, the transition was achieved by illuminating the ABC region with a train of 790-nm-wavelength laser pulses, and the transition was visualized by transmission electron microscopy in both diffraction and dark-field imaging modes. Further, using this approach, the DW was visualized at a nanoscale spatial resolution in the dark-field imaging mode.
基金by the Natural National Science Foundation of China(41888101 and 42125206)and the Key Research Program of the Institute of Geology&Geophysics,Chinese Academy of Sciences(IGGCAS-201905).
文摘When it comes to convection,what goes up must come down.Or is it,what goes down must come up?The truth is,it depends.Although convection must be mass-balanced,there is no reason that it must be force-balanced:the positive and negative buoyancy forces driving convection up and down,respectively,do not necessarily need to be balanced.The balance,or imbalance,all depends on the top and bottom boundary layers.
