Chemical transformation,nutrient release and changes in the energy content of decomposing rape,sunflower and soybean residues confined in buried fiberglass bage were assessed in a laboratory study during a 340-day inc...Chemical transformation,nutrient release and changes in the energy content of decomposing rape,sunflower and soybean residues confined in buried fiberglass bage were assessed in a laboratory study during a 340-day incubation period.The organic C decreased by about 70% while total N,after initial decay,remained almost constant for each type of residue.The NH4^+-N was progressively oxidized and,consequently,the NO3^-N increased.The C/N ratio narrowed with loss of C.Hemicellulose,cellulose and lignin decreased with different trends for each crop residue.The energy content,was reduced to about 25% in rape,30% in sunflower and 20% in soybean residues.Total P,K,Ca and Mg contents decreased for each type of residue The results suggest that the three residues could imporve the nutrient pool of the soil.展开更多
Experiments were performed to investigate the change of hepatic T4 5'-deiodination and the preventive effects of selenium (Se) and vitamin E in rats fed grains from a Keshan disease (KD) endemic area. The results ...Experiments were performed to investigate the change of hepatic T4 5'-deiodination and the preventive effects of selenium (Se) and vitamin E in rats fed grains from a Keshan disease (KD) endemic area. The results showed that consumption of the endemic grain for 8 weeks caused a significant reduction in hepatic T4 5'-monodeiodinase and glutathione peroxidase activities, and a marked enhancement of hepatic malondialdehyde content. These changes could be effectively prevented through Se or vitamin E supplementation to the diet. These observations confirm the reduced ability of hepatic T4 5'-deiodination induced by the pathogenic factors existing in the endemic grains, and the preventive effects of selenium and vitamin E on the alterations. The present study suggests that the reduction in hepatic T4 deiodination in these animals may be the consequence of hepatic damage owing to uncontrolled free radical metabolism, and that the relative deficiency of vitamin E, besides selenium deficiency, may also play a role in the pathogenesis of KD.展开更多
Polar auxin transport plays a divergent role in plant growth and developmental processes including root and embryo development, vascular pattern formation and cell elongation. Recently isolated Arabidopsis pin gene fa...Polar auxin transport plays a divergent role in plant growth and developmental processes including root and embryo development, vascular pattern formation and cell elongation. Recently isolated Arabidopsis pin gene family was believed to encode a component of auxin efflux carrier (G(?)lweiler et al, 1998). Based on the Arabidopsis pin1 sequence we have isolated a Brassica juncea cDNA (designated Bjpin1), which encoded a 70-kDa putative auxin efflux carrier. Deduced BjPIN1 shared 65% identities at protein level with AtPINl and was highly homologous to other putative PIN proteins of Arabidopsis (with highest homology to AtPIN3). Hydrophobic analysis showed similar structures between BjPINl and AtPIN proteins. Presence of 6 exons (varying in size between 65 bp and 1229 bp) and 5 introns (sizes between 89 bp and 463 bp) in the genomic fragment was revealed by comparing the genomic and cDNA sequences. Northern blot analysis indicated that Bjpin1 was expressed in most of the tissues tested, with a relatively higher level of transcript in flowers and a lower level in root tissues. Promoter-reporter gene fusion studies further revealed the expression of Bjpin1 in the mature pollen grains, young seeds, root tip, leaf vascular tissue and trace bundle, stem epidermis, cortex and vascular cells. BjPINl was localized on the plasma membrane as demonstrated through fusion expression of green fluorescent protein (GFP). Auxin efflux carrier activity was elevated in transgenic Arabidopsis expressing BjPIN1.展开更多
The present study was carried out on rat heart to in situ determine the myocardial toxicity of moniliformin, a synthesized compound, originally isolated from mouldy corn and soil samples in the Keshan disease prevalen...The present study was carried out on rat heart to in situ determine the myocardial toxicity of moniliformin, a synthesized compound, originally isolated from mouldy corn and soil samples in the Keshan disease prevalent area in China. Perfusion of moniliformin 10~(-7 mol/liter in isolated heart decreased myocardial contractile force by 52±17%. Intravenous injection of moniliformin at 1/6 and 1/4 LD50 markedly inhibited cardiac hemodynamic variables relative to myocardial contractile function. Particularly, it decreased ±LV dP/dt max by 52± 6%, and induced ventricular arrhythmia. These data indicate that moniliformin is toxic to mammalian heart and might be an important factor relative to Keshan disease.展开更多
Inherent heterogeneity and distribution of knowledge strongly prevent knowledge from sharing and reusing among different agents and software entities, and a formal ontology has been viewed as a promising means to tack...Inherent heterogeneity and distribution of knowledge strongly prevent knowledge from sharing and reusing among different agents and software entities, and a formal ontology has been viewed as a promising means to tackle this problem. In this paper, a domain-specific formal ontology of archaeology is presented. The ontology mainly consists of three parts: archaeological categories, their relationships and axioms. The ontology not only captures the semantics of archaeological knowledge, but also provides archaeology with an explicit and formal specification of a shared conceptualization, thus making archaeological knowledge shareable and reusable across humans and machines in a structured fashion. Further, we propose a method to verify ontology. correctness based on the individuals of categories. As applications of the ontology,we have developed an ontology-driven approach to knowledge acquisition from archaeological text and a question answering system for archaeological knowledge.展开更多
Techniques using Coanda effect have been applied to the fiuid control devices. In this field, experimental studies were so far performed for the spiral jet obtained by the Coanda jet issuing from a conical cylinder wi...Techniques using Coanda effect have been applied to the fiuid control devices. In this field, experimental studies were so far performed for the spiral jet obtained by the Coanda jet issuing from a conical cylinder with an annular slit, thrust vectoring of supersonic Coanda jets and so on. It is important from the viewpoints of effective applications to investigate the characteristics of the supersonic Coanda jet in detail. In the present study the effects of pressure ratios and nozzle configurations on the characteristics of the supersonic Coanda jet have been investigated experhoentally by a schlieren optical method and pressure measurements. Furthermore, Navier-Stokes equations were solved numerically using a 2nd-order TVD finite-volume scheme with a 3rd-rorder three stage Runge-Kutta method for time integration. k - ε model was used in the computations. The effects of initial conditions on Coandaflow were investigated numerically As a result, the simulated flow helds were compared with experimental data in good agreement qualitatively.展开更多
The surface of capillary wall can be treated to have a periodic microrelief mathematically. The roughness is micro enough compared with the thickness of the liquid film. So, the surface roughness only exerts influence...The surface of capillary wall can be treated to have a periodic microrelief mathematically. The roughness is micro enough compared with the thickness of the liquid film. So, the surface roughness only exerts influence on the adsorptive potential. Macroscopically, the flow field of the liquid film can be considered as that when the rough surface has an equivalent smooth surface, whose position is at the crests of the microrelief. The mechanism of heat transfer is in connection with two resistances: the thermal resistance of the liquid film conduction and the thermal resistance of the interfacial evaporation. The capillary pressure between the two sides of the vapor-liquid interface due to the interfacial curvature and the disjoining pressure owing to the thin liquid film are considered simultaneously. Several micro tubes with different micro rough surfaces are studied. The length of the evaporating interfacial region decreases with the increase of roughness angle and/or the increase of the roughness height. The heat transfer coefficient and the temperature of the vapor-liquid interface will change to fit the constant mass flow rate.展开更多
文摘Chemical transformation,nutrient release and changes in the energy content of decomposing rape,sunflower and soybean residues confined in buried fiberglass bage were assessed in a laboratory study during a 340-day incubation period.The organic C decreased by about 70% while total N,after initial decay,remained almost constant for each type of residue.The NH4^+-N was progressively oxidized and,consequently,the NO3^-N increased.The C/N ratio narrowed with loss of C.Hemicellulose,cellulose and lignin decreased with different trends for each crop residue.The energy content,was reduced to about 25% in rape,30% in sunflower and 20% in soybean residues.Total P,K,Ca and Mg contents decreased for each type of residue The results suggest that the three residues could imporve the nutrient pool of the soil.
文摘Experiments were performed to investigate the change of hepatic T4 5'-deiodination and the preventive effects of selenium (Se) and vitamin E in rats fed grains from a Keshan disease (KD) endemic area. The results showed that consumption of the endemic grain for 8 weeks caused a significant reduction in hepatic T4 5'-monodeiodinase and glutathione peroxidase activities, and a marked enhancement of hepatic malondialdehyde content. These changes could be effectively prevented through Se or vitamin E supplementation to the diet. These observations confirm the reduced ability of hepatic T4 5'-deiodination induced by the pathogenic factors existing in the endemic grains, and the preventive effects of selenium and vitamin E on the alterations. The present study suggests that the reduction in hepatic T4 deiodination in these animals may be the consequence of hepatic damage owing to uncontrolled free radical metabolism, and that the relative deficiency of vitamin E, besides selenium deficiency, may also play a role in the pathogenesis of KD.
基金Studies were supported by 'the National NaturalScience Foundation of China, No. 30070073', StateKey Project of Basic Research, No. G199901l604'and 'National Natural Science Foundation of Pan-Deng'. We thank Dr. Charles Brearley and JianXu for hel
文摘Polar auxin transport plays a divergent role in plant growth and developmental processes including root and embryo development, vascular pattern formation and cell elongation. Recently isolated Arabidopsis pin gene family was believed to encode a component of auxin efflux carrier (G(?)lweiler et al, 1998). Based on the Arabidopsis pin1 sequence we have isolated a Brassica juncea cDNA (designated Bjpin1), which encoded a 70-kDa putative auxin efflux carrier. Deduced BjPIN1 shared 65% identities at protein level with AtPINl and was highly homologous to other putative PIN proteins of Arabidopsis (with highest homology to AtPIN3). Hydrophobic analysis showed similar structures between BjPINl and AtPIN proteins. Presence of 6 exons (varying in size between 65 bp and 1229 bp) and 5 introns (sizes between 89 bp and 463 bp) in the genomic fragment was revealed by comparing the genomic and cDNA sequences. Northern blot analysis indicated that Bjpin1 was expressed in most of the tissues tested, with a relatively higher level of transcript in flowers and a lower level in root tissues. Promoter-reporter gene fusion studies further revealed the expression of Bjpin1 in the mature pollen grains, young seeds, root tip, leaf vascular tissue and trace bundle, stem epidermis, cortex and vascular cells. BjPINl was localized on the plasma membrane as demonstrated through fusion expression of green fluorescent protein (GFP). Auxin efflux carrier activity was elevated in transgenic Arabidopsis expressing BjPIN1.
文摘The present study was carried out on rat heart to in situ determine the myocardial toxicity of moniliformin, a synthesized compound, originally isolated from mouldy corn and soil samples in the Keshan disease prevalent area in China. Perfusion of moniliformin 10~(-7 mol/liter in isolated heart decreased myocardial contractile force by 52±17%. Intravenous injection of moniliformin at 1/6 and 1/4 LD50 markedly inhibited cardiac hemodynamic variables relative to myocardial contractile function. Particularly, it decreased ±LV dP/dt max by 52± 6%, and induced ventricular arrhythmia. These data indicate that moniliformin is toxic to mammalian heart and might be an important factor relative to Keshan disease.
文摘Inherent heterogeneity and distribution of knowledge strongly prevent knowledge from sharing and reusing among different agents and software entities, and a formal ontology has been viewed as a promising means to tackle this problem. In this paper, a domain-specific formal ontology of archaeology is presented. The ontology mainly consists of three parts: archaeological categories, their relationships and axioms. The ontology not only captures the semantics of archaeological knowledge, but also provides archaeology with an explicit and formal specification of a shared conceptualization, thus making archaeological knowledge shareable and reusable across humans and machines in a structured fashion. Further, we propose a method to verify ontology. correctness based on the individuals of categories. As applications of the ontology,we have developed an ontology-driven approach to knowledge acquisition from archaeological text and a question answering system for archaeological knowledge.
文摘Techniques using Coanda effect have been applied to the fiuid control devices. In this field, experimental studies were so far performed for the spiral jet obtained by the Coanda jet issuing from a conical cylinder with an annular slit, thrust vectoring of supersonic Coanda jets and so on. It is important from the viewpoints of effective applications to investigate the characteristics of the supersonic Coanda jet in detail. In the present study the effects of pressure ratios and nozzle configurations on the characteristics of the supersonic Coanda jet have been investigated experhoentally by a schlieren optical method and pressure measurements. Furthermore, Navier-Stokes equations were solved numerically using a 2nd-order TVD finite-volume scheme with a 3rd-rorder three stage Runge-Kutta method for time integration. k - ε model was used in the computations. The effects of initial conditions on Coandaflow were investigated numerically As a result, the simulated flow helds were compared with experimental data in good agreement qualitatively.
基金NationalNW Sdence Foundation of China with the fort No.59995550-4 and the POst-doctoral FOundation. Thesupports are gIatef
文摘The surface of capillary wall can be treated to have a periodic microrelief mathematically. The roughness is micro enough compared with the thickness of the liquid film. So, the surface roughness only exerts influence on the adsorptive potential. Macroscopically, the flow field of the liquid film can be considered as that when the rough surface has an equivalent smooth surface, whose position is at the crests of the microrelief. The mechanism of heat transfer is in connection with two resistances: the thermal resistance of the liquid film conduction and the thermal resistance of the interfacial evaporation. The capillary pressure between the two sides of the vapor-liquid interface due to the interfacial curvature and the disjoining pressure owing to the thin liquid film are considered simultaneously. Several micro tubes with different micro rough surfaces are studied. The length of the evaporating interfacial region decreases with the increase of roughness angle and/or the increase of the roughness height. The heat transfer coefficient and the temperature of the vapor-liquid interface will change to fit the constant mass flow rate.
