Natural convection heat transfer inside horizontal rectangular enclosure filled with the anisotropic porous media, with isothermally heated bottom and cooled top while the vertical walls are adiabatic, is analyzed num...Natural convection heat transfer inside horizontal rectangular enclosure filled with the anisotropic porous media, with isothermally heated bottom and cooled top while the vertical walls are adiabatic, is analyzed numerically by applying the Brinkman model-a modified form of Darcy model giving consideration to the viscous effect. The results show that: (1)the permeability ratio (K*=Ky/Kx) is an important factor affecting natural convection heat transfer in the porous media. As K' decreases, the circulation intensity of the natural convectioncells increase significantly, resulting in an enhancement of heat transfer coefficient; (2)the increase of Darcy number (aa=Ky/H2) implies that the viscous effect is more significant. As Da≥10-, there exists a certain difference between the Darcy model and the Brinkman model. It is more significant at a lower permeability ratio. In particalar, with K*≤0. 25, the Nusselt number for Da=10-3 would differ form that of Darcy model up to an amount of 30K. The Darcy flow as depicted by Darcy model is no longer existing and an analysis neglecting the viscous effect will inevitably be of considerable error.展开更多
We have previously shown a critical role of prolactin (PRL) during maturation and anti-tumor effects of murine natural killer (NK) cells in vitro and in vivo. We extended that study by exploring the ability of human N...We have previously shown a critical role of prolactin (PRL) during maturation and anti-tumor effects of murine natural killer (NK) cells in vitro and in vivo. We extended that study by exploring the ability of human NK cell lines (NK-92 and YT cell) to express PRL receptor (PRL-R) and to respond to PRL stimulation in vitro. Both human NK cell lines constitutively expressed PRL-R on membrane and mRNA transcripts,NK-92 cells contained higher level of PRL-R than YT cells,which correlated to the enhanced capacity of the cells to proliferate and to lyse target cells in response to PRL stimulation in the presence of trace amount of IL-2 or IL-15 in vitro. Two differences between IL-2 and IL-15 in functioning on human NK cells were for the first time observed. PRL synergized with IL-15 to improve proliferation of NK cells in a dose-dependent manner without double peak manifesting like IL-2. Although PRL enhanced the cytotoxicity of IL-2 or IL- 15 activated NK cells,it exerted the function through up-regulating gene expression of perforin without influence of FasL in IL-2-stimulated NK cells,while in IL-15-stimulated NK cells,PRL did the function through up-regulating gene expression of both perforin and FasL but not IFNγ. PRL increased expressions of IL-2Rα on membrane and of IL-2 mRNA in cells,indicating that PRL up-regulated NK cell function by improving positive feedback between IL-2 and IL-2R. The similar results were also observed in network between IL-15 and IL-15R. These data indicate a potential role of PRL in human NK cell modulation.展开更多
Entanglement dynamics of the atoms in the double Jaynes-Cummings models with the Kerr medium isstudied, and the effect of the Kerr medium on that is examined.The result shows that, the Kerr medium can control theentan...Entanglement dynamics of the atoms in the double Jaynes-Cummings models with the Kerr medium isstudied, and the effect of the Kerr medium on that is examined.The result shows that, the Kerr medium can control theentanglement dynamics of the atoms and repress entanglement sudden death.We can obtain the maximum entanglementbetween the atoms by strengthening the nonlinear interaction of the Kerr medium.展开更多
The lethal effect produced by sunlight in bacteria depends on the photodynamic action of the ultraviolet component of the radiation. Neither the reactive oxygen species involved nor the targets for damage have been ce...The lethal effect produced by sunlight in bacteria depends on the photodynamic action of the ultraviolet component of the radiation. Neither the reactive oxygen species involved nor the targets for damage have been certainly identified, and the aim of this study was to address these issues. During exposures to natural sunlight, photo-protection provided by nitrogen sparging was compared with which provided by the addition of L-histidine (an efficient scavenger for hydroxyl radical and singlet oxygen) or mannitol (an hydroxyl radical scavenger which reacts poorly with singlet oxygen) to the irradiation medium. Both scavengers reproduced for the most part the effect of oxygen depletion, indicating that damage depends mainly on hydroxyl radical generation. Survival of irradiated bacteria decreased considerably when they were cultured using a substrate unsuitable for fermentation, suggesting that respiration impairment is a key factor in cell killing. This observation is in keeping with the notion that the respiratory chain is the main target for the action of sunlight in Escherichia coli.展开更多
: To study the effect of acupuncture on interleukin 2 (IL 2)-interferon(IFN)-natural killer cells (NKC) immunoregulatory network of mice with transplanted hepatocarcinoma(HAC) in order to provide new evidence for acup...: To study the effect of acupuncture on interleukin 2 (IL 2)-interferon(IFN)-natural killer cells (NKC) immunoregulatory network of mice with transplanted hepatocarcinoma(HAC) in order to provide new evidence for acupuncture treatment of hypofunction of immune system. Methods:The 28 HAC-vaccinated BALB/C mice are randomly divided into control group (n=14) and acupunctrue group (n=14). In the latter group bilateral'Dazhui' (BL 11) and 'Zusanili' (ST 36) which are located according to the same positions indicated in Comparative Anatomy of Macro-animals, are needled once every day, twelve sessions altogether. Twenty-four hours after the needling treatment the mice are killed and the spleen is taken out to be made into cell suspension for assaying concentrations of IL2 (MTT method) and NKC (colorimetric method) respectively. Obital Serum IFN is determined by using (CPE microplate staining), and the tumor mass is taken out and balanced with an analytical balance (1/10000) to calculate the tumor inhibition rate according to the formula. Results: The tumor weight of the mice of aupuncture group is obviously decreased (inhibition rate 43.06%) while the activity of the IL2 and NKC, and the IFN tiler are increased greatly, which have significant differences compared with those of control group (P>0.01). Conclusion:The results of the study show that acupuncture can strengthen the positive immunoregulatory function of the IL2 -IFN-NKC network in immune hypofunction mice bearing HAC.展开更多
The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (...The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (SDS) existing in the system.The results show that A-type zeolite can influence methane hydrate formation.At the temperature of 273.5 K and pressure of 8.3 MPa,the distilled water with A-type zeolite can form methane hydrate with gaseous methane in 12 hours.The formation process of the system with A-type zeolite was quite steady and the amount of A-type zeolite can influence the gas storage capacity significantly.The adding of A-type zeolite with 0.067 g·(g water)-1 into 2×10-3 g·g-1 SDS-water solution can increase the gas storage capacity,and the maximum increase rate was 31%.Simultaneously the promotion effect on hydrate formation of 3A-type zeolite is much more obvious than that of 5A-type zeolite when the water adding amounts are 0.033 g·g-1 and 0.067 g·g-1 at the experimental conditions.展开更多
In the present work the effect of the power law exponent of power-law fluid and non-Darcy number of non-Darcy flow on stability of natural convection in porous media are studied. The computation analysis of effect of ...In the present work the effect of the power law exponent of power-law fluid and non-Darcy number of non-Darcy flow on stability of natural convection in porous media are studied. The computation analysis of effect of powerlaw exponent of power-law fluid and non-Darcy number of non-Darcy flow in the rectangular duct on the transition Rayleigh number Ra, which means the convective model transiting from stationary state to periodic solution. The duct has filled a porous medium saturated with the power-law non-Newtonian fluid or Newtonian fluid for non-Darcy now, in which there is uniform internal heat generation per unit volume q. In thes paper the relationship between the transition Rayleigh number Ra* and the power-law exponent n, Ra* and non-Darcy number Be, are shown .To these two aspects, the transition route from steady to chaotic convection is also obtained.展开更多
Natural convection heat transfer in a horizontal enclosure filled with anisotropic porous media,being isothermally heated at bettom and cooled at top while the vertical walls being adiabatic, is numerically studied by...Natural convection heat transfer in a horizontal enclosure filled with anisotropic porous media,being isothermally heated at bettom and cooled at top while the vertical walls being adiabatic, is numerically studied by applying the Brinkman model-a modified form of Darcy model giving consideration to the viscous effect. The results show that:(1)a larger permeability ratio (K*) causes a lower flow intensity in the enclosure and a smaller Nusselt number, all Nusselt numbers approach unity in the limit of K* → ∞;a larger thermal conductivity ratio (λ*) causes a stranger distortion of isotherms in the enclosure and a higher flow velocity near the walls, all the Nusselt numbers approach unity in the limit of λ*→0; the permeability and thermal conductivity ratios generally have opposing effects on the Nusselt number. (2) an increasing Darcy number decreases the flow intensity and heat transfer rates,which is more significant at a lower permeability ratio. In particular, with K*0.25, the Nusselt number for Da=10-3 would differ from that of Darcy flow up to an amount of 30%, an analysis neglecting the non-Darican effect will inevitably be of considerable error.展开更多
We measured in the laboratory compressional wave velocity and electrical resistivity on 434 sediment samples collected from the Yellow Sea to study the joint elastic-electrical properties of marine sediments. Porosity...We measured in the laboratory compressional wave velocity and electrical resistivity on 434 sediment samples collected from the Yellow Sea to study the joint elastic-electrical properties of marine sediments. Porosity was found to reduce both elastic velocity and electrical resistivity of the marine sediments in a non-linear fashion; velocity showed an approximate linear increase with increasing logarithm of resistivity. Various effective medium models either implemented or developed were compared with the new dataset. The model results showed that the combined self-consistent approximation and differential effective medium model using critical porosity of 0.6 and 0.5 for velocity and resistivity respectively gave a reasonable description of the joint elastic-electrical behaviors of the marine sediments. The joint elastic-electrical properties of the marine sediments established would be used to estimate resistivity from measured velocity and vice versa, and could also be suitable for detection of gas hydrate or other suitable targets from joint seismic-resistivity surveys.展开更多
文摘Natural convection heat transfer inside horizontal rectangular enclosure filled with the anisotropic porous media, with isothermally heated bottom and cooled top while the vertical walls are adiabatic, is analyzed numerically by applying the Brinkman model-a modified form of Darcy model giving consideration to the viscous effect. The results show that: (1)the permeability ratio (K*=Ky/Kx) is an important factor affecting natural convection heat transfer in the porous media. As K' decreases, the circulation intensity of the natural convectioncells increase significantly, resulting in an enhancement of heat transfer coefficient; (2)the increase of Darcy number (aa=Ky/H2) implies that the viscous effect is more significant. As Da≥10-, there exists a certain difference between the Darcy model and the Brinkman model. It is more significant at a lower permeability ratio. In particalar, with K*≤0. 25, the Nusselt number for Da=10-3 would differ form that of Darcy model up to an amount of 30K. The Darcy flow as depicted by Darcy model is no longer existing and an analysis neglecting the viscous effect will inevitably be of considerable error.
基金supported partly by Outstanding Young Scientist Award and Key Project by Natural Science Foundation of China(No.30125038,No.30230340)The Major Sate Basic research Development program of China(No.2001CB510009)+1 种基金The National high technology research and Development program of China(No.2002AA216151)by Ministry of Science and Technology of ChinaKey Project by Chinese Academy of Science(No.KSCX2-2-08).
文摘We have previously shown a critical role of prolactin (PRL) during maturation and anti-tumor effects of murine natural killer (NK) cells in vitro and in vivo. We extended that study by exploring the ability of human NK cell lines (NK-92 and YT cell) to express PRL receptor (PRL-R) and to respond to PRL stimulation in vitro. Both human NK cell lines constitutively expressed PRL-R on membrane and mRNA transcripts,NK-92 cells contained higher level of PRL-R than YT cells,which correlated to the enhanced capacity of the cells to proliferate and to lyse target cells in response to PRL stimulation in the presence of trace amount of IL-2 or IL-15 in vitro. Two differences between IL-2 and IL-15 in functioning on human NK cells were for the first time observed. PRL synergized with IL-15 to improve proliferation of NK cells in a dose-dependent manner without double peak manifesting like IL-2. Although PRL enhanced the cytotoxicity of IL-2 or IL- 15 activated NK cells,it exerted the function through up-regulating gene expression of perforin without influence of FasL in IL-2-stimulated NK cells,while in IL-15-stimulated NK cells,PRL did the function through up-regulating gene expression of both perforin and FasL but not IFNγ. PRL increased expressions of IL-2Rα on membrane and of IL-2 mRNA in cells,indicating that PRL up-regulated NK cell function by improving positive feedback between IL-2 and IL-2R. The similar results were also observed in network between IL-15 and IL-15R. These data indicate a potential role of PRL in human NK cell modulation.
基金Supported by the National Natural Science Foundation of China under Grant No.10374025 the Natural Science Foundation of Hunan Province under Grant No.07JJ3013 the Education Ministry of Hunan Province under Grant No.06A038
文摘Entanglement dynamics of the atoms in the double Jaynes-Cummings models with the Kerr medium isstudied, and the effect of the Kerr medium on that is examined.The result shows that, the Kerr medium can control theentanglement dynamics of the atoms and repress entanglement sudden death.We can obtain the maximum entanglementbetween the atoms by strengthening the nonlinear interaction of the Kerr medium.
文摘The lethal effect produced by sunlight in bacteria depends on the photodynamic action of the ultraviolet component of the radiation. Neither the reactive oxygen species involved nor the targets for damage have been certainly identified, and the aim of this study was to address these issues. During exposures to natural sunlight, photo-protection provided by nitrogen sparging was compared with which provided by the addition of L-histidine (an efficient scavenger for hydroxyl radical and singlet oxygen) or mannitol (an hydroxyl radical scavenger which reacts poorly with singlet oxygen) to the irradiation medium. Both scavengers reproduced for the most part the effect of oxygen depletion, indicating that damage depends mainly on hydroxyl radical generation. Survival of irradiated bacteria decreased considerably when they were cultured using a substrate unsuitable for fermentation, suggesting that respiration impairment is a key factor in cell killing. This observation is in keeping with the notion that the respiratory chain is the main target for the action of sunlight in Escherichia coli.
基金the National Natural Science Fundationa of China(38970885)
文摘: To study the effect of acupuncture on interleukin 2 (IL 2)-interferon(IFN)-natural killer cells (NKC) immunoregulatory network of mice with transplanted hepatocarcinoma(HAC) in order to provide new evidence for acupuncture treatment of hypofunction of immune system. Methods:The 28 HAC-vaccinated BALB/C mice are randomly divided into control group (n=14) and acupunctrue group (n=14). In the latter group bilateral'Dazhui' (BL 11) and 'Zusanili' (ST 36) which are located according to the same positions indicated in Comparative Anatomy of Macro-animals, are needled once every day, twelve sessions altogether. Twenty-four hours after the needling treatment the mice are killed and the spleen is taken out to be made into cell suspension for assaying concentrations of IL2 (MTT method) and NKC (colorimetric method) respectively. Obital Serum IFN is determined by using (CPE microplate staining), and the tumor mass is taken out and balanced with an analytical balance (1/10000) to calculate the tumor inhibition rate according to the formula. Results: The tumor weight of the mice of aupuncture group is obviously decreased (inhibition rate 43.06%) while the activity of the IL2 and NKC, and the IFN tiler are increased greatly, which have significant differences compared with those of control group (P>0.01). Conclusion:The results of the study show that acupuncture can strengthen the positive immunoregulatory function of the IL2 -IFN-NKC network in immune hypofunction mice bearing HAC.
基金Supported by the National Natural Science Foundation of China (50876107), the National Basic Research Program of China (2009CB219504), NSFC-Guangdong Union Foundation (NSFC-U0733033) and CAS Program (KGCX2-YW-805).
文摘The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (SDS) existing in the system.The results show that A-type zeolite can influence methane hydrate formation.At the temperature of 273.5 K and pressure of 8.3 MPa,the distilled water with A-type zeolite can form methane hydrate with gaseous methane in 12 hours.The formation process of the system with A-type zeolite was quite steady and the amount of A-type zeolite can influence the gas storage capacity significantly.The adding of A-type zeolite with 0.067 g·(g water)-1 into 2×10-3 g·g-1 SDS-water solution can increase the gas storage capacity,and the maximum increase rate was 31%.Simultaneously the promotion effect on hydrate formation of 3A-type zeolite is much more obvious than that of 5A-type zeolite when the water adding amounts are 0.033 g·g-1 and 0.067 g·g-1 at the experimental conditions.
文摘In the present work the effect of the power law exponent of power-law fluid and non-Darcy number of non-Darcy flow on stability of natural convection in porous media are studied. The computation analysis of effect of powerlaw exponent of power-law fluid and non-Darcy number of non-Darcy flow in the rectangular duct on the transition Rayleigh number Ra, which means the convective model transiting from stationary state to periodic solution. The duct has filled a porous medium saturated with the power-law non-Newtonian fluid or Newtonian fluid for non-Darcy now, in which there is uniform internal heat generation per unit volume q. In thes paper the relationship between the transition Rayleigh number Ra* and the power-law exponent n, Ra* and non-Darcy number Be, are shown .To these two aspects, the transition route from steady to chaotic convection is also obtained.
文摘Natural convection heat transfer in a horizontal enclosure filled with anisotropic porous media,being isothermally heated at bettom and cooled at top while the vertical walls being adiabatic, is numerically studied by applying the Brinkman model-a modified form of Darcy model giving consideration to the viscous effect. The results show that:(1)a larger permeability ratio (K*) causes a lower flow intensity in the enclosure and a smaller Nusselt number, all Nusselt numbers approach unity in the limit of K* → ∞;a larger thermal conductivity ratio (λ*) causes a stranger distortion of isotherms in the enclosure and a higher flow velocity near the walls, all the Nusselt numbers approach unity in the limit of λ*→0; the permeability and thermal conductivity ratios generally have opposing effects on the Nusselt number. (2) an increasing Darcy number decreases the flow intensity and heat transfer rates,which is more significant at a lower permeability ratio. In particular, with K*0.25, the Nusselt number for Da=10-3 would differ from that of Darcy flow up to an amount of 30%, an analysis neglecting the non-Darican effect will inevitably be of considerable error.
基金supported by the Oceanic Special Public Sector Research Project (Grant No. 200805008)
文摘We measured in the laboratory compressional wave velocity and electrical resistivity on 434 sediment samples collected from the Yellow Sea to study the joint elastic-electrical properties of marine sediments. Porosity was found to reduce both elastic velocity and electrical resistivity of the marine sediments in a non-linear fashion; velocity showed an approximate linear increase with increasing logarithm of resistivity. Various effective medium models either implemented or developed were compared with the new dataset. The model results showed that the combined self-consistent approximation and differential effective medium model using critical porosity of 0.6 and 0.5 for velocity and resistivity respectively gave a reasonable description of the joint elastic-electrical behaviors of the marine sediments. The joint elastic-electrical properties of the marine sediments established would be used to estimate resistivity from measured velocity and vice versa, and could also be suitable for detection of gas hydrate or other suitable targets from joint seismic-resistivity surveys.