Objective： Correct nutritional assessment is essential for leukemia patients after hematopoietic stem cell transplantation （HSCT）. This study aimed to investigate the best nutritional assessment method for leukemia...Objective： Correct nutritional assessment is essential for leukemia patients after hematopoietic stem cell transplantation （HSCT）. This study aimed to investigate the best nutritional assessment method for leukemia patients after HSCT, and find the possible nutritional risk of the patients during the transplantation process in order to intervene in the patients with nutritional risks and undernourished patients timely, so that the entire transplantation process could be successfully completed. Methods： A prospective study was performed in 108 leukemia patients after HSCT, and different nutritional assessment methods, including nutritional risk screening 2002 （NRS2002）, mini nutritional assessment （MNA）, subjective globe assessment （SGA） and malnutritional universal screening tools （MUST）, were used. The associations between nutritional status of these patients and nutritional assessment methods were analyzed. Results： A total of 108 patients completed SGA, and 99 patients completed NRS2002, MNA and MUST. During the treatment process, 85.2% of the patients lost weight, wherein, 50% lost weight greater than 5%, and 42.6% had significantly reduced food intake. For nutritional risk assessment, the positive rates of NRS2002, MNA and MUST were 100%, 74.7% and 63.6%, respectively. There was a significant difference （P〈0.05） among the positive rates of NRS2002, MNA and MUST. In undernutrition assessment, the positive rate of SGA （83.3%） was significantly higher than that of MNA （17.2%） （P〈0.05）, and the incidence rate of nutritional risk among leukemia patients _〈30 years old was greater than that of patients 〉30 years old （P〈0.05）. Conclusions： Patients with leukemia were in poor nutritional status during and after HSCT. The leukemia patients 〈30 years old had a greater incidence rate of nutritional risk. As nutritional risk screening tool, the specificity of NRS2002 is not high, but it can be used for evaluating nutritional deficiencies. MNA is a good nutritio展开更多
microRNAs （miRNAs） play an important regulatory role in the self-renewal and differentiation of stem cells. In this study, we examined the effects of miRNA-124 （miR-124） overexpression in bone marrow-derived mesen...microRNAs （miRNAs） play an important regulatory role in the self-renewal and differentiation of stem cells. In this study, we examined the effects of miRNA-124 （miR-124） overexpression in bone marrow-derived mesenchymal stem cells. In particular, we focused on the effect of overexpression on the differentiation of bone marrow-derived mesenchymal stem cells into neurons. First, we used GeneChip technology to analyze the expression of miRNAs in bone marrow-derived mesen- chymal stem cells, neural stem cells and neurons, miR-124 expression was substantially reduced in bone marrow-derived mesenchymal stem cells compared with the other cell types. We con- structed a lentiviral vector overexpressing miR-124 and transfected it into bone marrow-derived mesenchymal stem cells. Intracellular expression levels of the neuronal early markers [3-III tu- bulin and microtubule-associated protein-2 were significantly increased, and apoptosis induced by oxygen and glucose deprivation was reduced in transfected cells. After miR-124-transfected bone marrow-derived mesenchymal stem cells were transplanted into the injured rat spinal cord, a large number of cells positive for the neuronal marker neurofilament-200 were observed in the transplanted region. The Basso-Beattie-Bresnahan locomotion scores showed that the motor function of the hind limb of rats with spinal cord injury was substantially improved. These re- sults suggest that miR-124 plays an important role in the differentiation of bone marrow-derived mesenchymal stem cells into neurons. Our findings should facilitate the development of novel strategies for enhancing the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for spinal cord injury.展开更多
Background Hematopoietic stem cells （HSCs） give rise to all blood and immune cells and are used in clinical transplantation protocols to treat a wide variety of refractory diseases, but the amplification of HSCs has...Background Hematopoietic stem cells （HSCs） give rise to all blood and immune cells and are used in clinical transplantation protocols to treat a wide variety of refractory diseases, but the amplification of HSCs has been difficult to achieve in vitro. In the present study, the expansive effects of aorta-gonad-mesonephros （AGM） region derived stromal cells on HSCs were explored, attempting to improve the efficiency of HSC transplantation in clinical practice.Methods The murine stromal cells were isolated from the AGM region of 12 days postcoitum （dpc） murine embryos and bone marrow（BM） of 6 weeks old mice, respectively. After identification with flow cytometry and immunocytochemistry, the stromal cells were co-cultured with ESCs-derived, cytokines-induced HSCs. The maintenance and expansion of ESCs-derived HSCs were evaluated by detecting the population of CD34^＋ and CD34^＋ Sca-1^＋ cells with flow cytometry and the blast colony-forming cells （BL-CFCs）, high proliferative potential colony-forming cells （HPP-CFCs） by using semi-solid medium colonial culture. Finally, the homing and hematopoietic reconstruction abilities of HSCs were evaluated using a murine model of HSC transplantation in vivo.Results AGM and BM-derived stromal cells were morphologically and phenotypically similar, and had the features of stromal cells. When co-cultured with AGM or BM stromal cells, more primitive progenitor cells （ HPP-CFCs ） could be detected in ESCs derived hematopoietic precursor cells, but BL-CFC＇ s expansion could be detected only when co-cultured with AGM-derived stromal cells. The population of CD34^＋ hematopoietic stem/ progenitor cells were expanded 3 times, but no significant expansion in the population of CD34^＋ Sca-1^＋ cells was noted when co-cultured with BM stromal cells. While both CD34^＋ hematopoietic stem/progenitor cells and CD34^＋ Sca-1^＋ cells were expanded 4 to 5 times respectively derived stromal cells, like BM-derived stromal cells, homing to BM in vivo. when co展开更多
Because of their strong proliferative capacity and multi-potency, placenta-derived mesenchymal stem cells have gained interest as a cell source in the field of nerve damage repair. In the present study, human placenta...Because of their strong proliferative capacity and multi-potency, placenta-derived mesenchymal stem cells have gained interest as a cell source in the field of nerve damage repair. In the present study, human placenta-derived mesenchymal stem ceils were induced to differentiate into neural stem cells, which were then transplanted into the spinal cord after local spinal cord injury in rats. The motor functional recovery and pathological changes in the injured spinal cord were observed for 3 successive weeks. The results showed that human placenta-derived mesenchymal stem cells can differentiate into neuron-like cells and that induced neural stem cells contribute to the restoration of injured spinal cord without causing transplant rejection. Thus, these cells promote the recovery of motor and sensory functions in a rat model of spinal cord injury. Therefore, human placenta-derived mesenchymal stem cells may be useful as seed cells during the repair of spinal cord injury.展开更多
Transplantation of neural stem cells has been reported as a possible approach for replacing impaired dopaminergic neurons. In this study, we tested the efficacy of early-stage human dental papilla-derived stem cells a...Transplantation of neural stem cells has been reported as a possible approach for replacing impaired dopaminergic neurons. In this study, we tested the efficacy of early-stage human dental papilla-derived stem cells and human brain-derived neural stem cells in rat models of 6-hydroxydopamine-induced Parkinson＇s disease. Rats received a unilateral injection of 6-hydroxydopamine into right medial forebrain bundle, followed 3 weeks later by injections of PBS, early-stage human dental papilla-derived stem cells, or human brain-derived neural stem cells into the ipsilateral striatum. All of the rats in the human dental papilla-derived stem cell group died from tumor formation at around 2 weeks following cell transplantation. Postmortem examinations revealed homogeneous malignant tumors in the striatum of the human dental papilla-derived stem cell group. Stepping tests revealed that human brain-derived neural stem cell transplantation did not improve motor dysfunction. In apomorphine-induced rotation tests, neither the human brain-derived neural stem cell group nor the control groups （PBS injection） demonstrated significant changes. Glucose metabolism in the lesioned side of striatum was reduced by human brain-derived neural stem cell transplantation. [18F]-FP-CIT PET scans in the striatum did not demonstrate a significant increase in the human brain-derived neural stem cell group. Tyrosine hydroxylase （dopaminergic neuronal marker） staining and G protein-activated inward rectifier potassium channel 2 （A9 dopaminergic neuronal marker） were positive in the lesioned side of striatum in the human brain-derived neural stem cell group. The use of early-stage human dental papilla-derived stern cells confirmed its tendency to form tumors. Human brain-derived neural stem cells could be partially differentiated into dopaminergic neurons, but they did not secrete dopamine.展开更多
In order to solve the severe vibration problems of an ocean engineering ship with a full-revolving propulsion system, the navigation tests, including forced vibration response test and modal test, are carded out in it...In order to solve the severe vibration problems of an ocean engineering ship with a full-revolving propulsion system, the navigation tests, including forced vibration response test and modal test, are carded out in its stem. It is concluded from the comparison of the time-domain waveform and spectrum from different measurement points that three main factors lead to a high-level stern vibration. Firstly, the specific dynamic stiffness of a water tank is relatively small compared with its neighbor hold, which makes it act like a vibration isolator preventing vibrational energy transmitting to the main hold. Secondly, there exists high-density local modes in the working frequency range of the main engine and thus the local resonance occurs. Thirdly, the abnormal engagement of gears caused by the large deflection of the shaft bearing due to its low mounting rigidity leads to violent extra impulse excitations at high speeds. Then the modification against the dynamic defects is given by simply improving the specific stiffness of the water tanks. And the effect is validated by the FEM calculation. Some important experience is obtained with the problems being solved, which is useful in the design of ships with the same propulsion system. It is also believed that the dynamic consideration is as important as the static analysis for the ships, and that most of the vibration problems may be avoided with a proper acoustic design.展开更多
In vitro experiments have demonstrated that neuronal-like cells derived from bone marrow mesen- chymal stem cells can survive, migrate, integrate and help to restore the function and behaviors of spinal cord injury mo...In vitro experiments have demonstrated that neuronal-like cells derived from bone marrow mesen- chymal stem cells can survive, migrate, integrate and help to restore the function and behaviors of spinal cord injury models, and that they may serve as a suitable approach to treating spinal cord injury. However, it is very difficult to track transplanted cells in vivo. In this study, we injected su- perparamagnetic iron oxide-labeled neuronal-like cells into the subarachnoid space in a rabbit model of spinal cord injury. At 7 days after cell transplantation, a small number of dot-shaped low signal intensity shadows were observed in the spinal cord injury region, and at 14 days, the number of these shadows increased on T2-weighted imaging. Perl＇s Prussian blue staining detected dot-shaped low signal intensity shadows in the spinal cord injury region, indicative of superpara- magnetic iron oxide nanoparticle-labeled cells. These findings suggest that transplanted neu- ronal-like cells derived from bone marrow mesenchymal stem cells can migrate to the spinal cord injury region and can be tracked by magnetic resonance in vivo. Magnetic resonance imaging represents an efficient noninvasive technique for visually tracking transplanted cells in vivo.展开更多
Glaucoma and other optic neuropathies result in optic nerve degeneration and the loss of retinal ganglion cells（RGCs）through complex signaling pathways.Although the mechanisms that regulate RGC development remain un...Glaucoma and other optic neuropathies result in optic nerve degeneration and the loss of retinal ganglion cells（RGCs）through complex signaling pathways.Although the mechanisms that regulate RGC development remain unclear,uncovering novel developmental pathways may support new strategies to regenerate the optic nerve or replace RGCs.Here we review recent studies that provide strong evidence that the Sry-related high-mobility-group C（SoxC）subfamily of transcription factors（TFs）are necessary and sufficient for axon guidance and RGC fate specification.These findings also uncover novel SoxC-dependent mechanisms that serve as master regulators during important steps of RGC development.For example,we review work showing that SoxC TFs regulate RGC axon guidance and direction through the optic chiasm towards their appropriate targets in the brain.We also review work demonstrating that Sox11 subcellular localization is,in part,controlled through small ubiquitin-like post-translational modifier（SUMO）and suggest compensatory cross-talk between Sox4 and Sox11.Furthermore,Sox4 overexpression is shown to positively drive RGC differentiation in human induced pluripotent stem cells（hi PSCs）.Finally,we discuss how these findings may contribute to the advancement of regenerative and cell-based therapies to treat glaucoma and other optic nerve neuropathies.展开更多
The effects of vascular endothelial growth factor （VEGF） on neural differentiation of human embryonic stem cells （hESCs） in vitro and the possible mechanism were observed. The hESCs lines, TJMU1 and TJMU2, were es...The effects of vascular endothelial growth factor （VEGF） on neural differentiation of human embryonic stem cells （hESCs） in vitro and the possible mechanism were observed. The hESCs lines, TJMU1 and TJMU2, were established and stored by our laboratory, hESCs differentiated into neuronal cells through embryonic body formation. In this induction process, hESCs were divided into three groups： group A, routine induction; group B, routine induction＋10 ng/mL VEGF; group C, routine in- duction＋10 ng/mL VEGF＋10 ng/mL VEGFR2/Fc. OCT4, Nestin and GFAP in each group were de- tected by RT-PCR, and the cells expressing Nestin and GFAP were counted by immunofluorescence. The percentage of Nestin positive cells in group B was significantly higher than in groups A and C, while the percentage of GFAP positive cells in group B was significantly lower than in groups A and C （P〈0.01）. There was no significant difference between groups A and C （P〉0.05）. It was concluded that VEGF, via VEGFR2, stimulated the neural differentiation of hESCs in vitro.展开更多
The coupled level-set and volume of fluid(CLSVOF)method is an advanced interface-capturing method that has been extended to handle overset grid systems.However,artificial uneven interface may be observed across block ...The coupled level-set and volume of fluid(CLSVOF)method is an advanced interface-capturing method that has been extended to handle overset grid systems.However,artificial uneven interface may be observed across block boundaries of different sizes and geometries.We present an improved inter-grid VOF interpolation and mass correction scheme to address the issue.To demonstrate the capability of the improved CLSVOF method,it is applied to the simulation of a container ship in pitch and heave motions under both head sea and following sea irregular wave conditions.Our simulation proves that the improved CLSVOF method is capable of revealing detailed physics difficult to see with other methods.Those phenomena simulated in our work include the extensive greenwater propagation on the ship deck,the breakup of overtopping waves into small droplets,and the formation and collapse of air pockets in sudden bow and stern slamming which cause strong and highly localized impacts on the ship bow,stern,and rudder.展开更多
Suitability of S-Glass/carbon fiber reinforced polymer composite for submarine hull subjected to hydrostatic pressure has been investigated in the present study.Metallic materials have raised concerns owing to their d...Suitability of S-Glass/carbon fiber reinforced polymer composite for submarine hull subjected to hydrostatic pressure has been investigated in the present study.Metallic materials have raised concerns owing to their decomposition due to low resistance towards salinity and hence polymer composites have been explored to showcase their mechanical stability to withstand transverse and impact loads.To this end,the mechanical properties of S-Glass/carbon fiber reinforced polymer composite were experimentally investigated and higher specific strength and stiffness of the composite in comparison to many metallic materials used for submarine hull were reported.The obtained experimental values were used for the static and dynamic crash analysis of the bow,stern and foil through Finite Element Analysis(FEA);where depth of travel was varied from sea surface level of 0-7000 m.Submarine assembly was later developed with the optimum shape and thickness of each part.We also report the nonlinear crash analysis upon impact at velocity ranging from 3 to 21 m/s.Besides,kinetic energy,acceleration peak and internal energy in struck submarine revealed that travel depth 1750 m and 3500 m is recommendable,more particularly,crash safety factor of the submarine is found to be within limit when submarine encounters crash at 1750 m.展开更多
The variations of ship stern flow field structure and its corresponding hydrodnamic performance under full scale Reynolds numbal (5 109) and model scale Reynolds numbal(5 106) are investigated numerically in this pape...The variations of ship stern flow field structure and its corresponding hydrodnamic performance under full scale Reynolds numbal (5 109) and model scale Reynolds numbal(5 106) are investigated numerically in this paper. The governing equations for 3-D incompressible turbulent flow which consist of RANS equation and K-ε two equation turbulence model are solved by finite difference scheme. Derailed computational results are presented graphically. The comparisons between present calculation, existing measurement and other calculation are made.展开更多
In this paper the complex structure and pattern of ship stern flow driven by multi-propellers is simulated numerically by using RANS equations with K turbulence model and propeller lifting surface theory as essential ...In this paper the complex structure and pattern of ship stern flow driven by multi-propellers is simulated numerically by using RANS equations with K turbulence model and propeller lifting surface theory as essential research tool and coupling the computer code of ship stern flow to the computer code of propeller performance prediction through the medium of body force. A ship model with four propellers is selected as the numerical example. Detailed computational results are presented graphically and the qualitative and quantitative analysis is made. Finally,the comparison between the calculated result and the avaikble experimental data is made. The agreement between them is satisfac-展开更多
Orlic et al treated mice （splenectomized two weeks ago） with granulocyte colony stimulating factor （G-CSF） and stem cell factor （SCF） for five days before acute myocardium infarction （AMI） and three days after...Orlic et al treated mice （splenectomized two weeks ago） with granulocyte colony stimulating factor （G-CSF） and stem cell factor （SCF） for five days before acute myocardium infarction （AMI） and three days after AMI. They found that those treatments could repair infarcted hearts, improve heart performance and decrease mortality. However, from the clinical standpoint, the work of Orlic and his co-workers has an obvious limitation.展开更多
文摘Objective： Correct nutritional assessment is essential for leukemia patients after hematopoietic stem cell transplantation （HSCT）. This study aimed to investigate the best nutritional assessment method for leukemia patients after HSCT, and find the possible nutritional risk of the patients during the transplantation process in order to intervene in the patients with nutritional risks and undernourished patients timely, so that the entire transplantation process could be successfully completed. Methods： A prospective study was performed in 108 leukemia patients after HSCT, and different nutritional assessment methods, including nutritional risk screening 2002 （NRS2002）, mini nutritional assessment （MNA）, subjective globe assessment （SGA） and malnutritional universal screening tools （MUST）, were used. The associations between nutritional status of these patients and nutritional assessment methods were analyzed. Results： A total of 108 patients completed SGA, and 99 patients completed NRS2002, MNA and MUST. During the treatment process, 85.2% of the patients lost weight, wherein, 50% lost weight greater than 5%, and 42.6% had significantly reduced food intake. For nutritional risk assessment, the positive rates of NRS2002, MNA and MUST were 100%, 74.7% and 63.6%, respectively. There was a significant difference （P〈0.05） among the positive rates of NRS2002, MNA and MUST. In undernutrition assessment, the positive rate of SGA （83.3%） was significantly higher than that of MNA （17.2%） （P〈0.05）, and the incidence rate of nutritional risk among leukemia patients _〈30 years old was greater than that of patients 〉30 years old （P〈0.05）. Conclusions： Patients with leukemia were in poor nutritional status during and after HSCT. The leukemia patients 〈30 years old had a greater incidence rate of nutritional risk. As nutritional risk screening tool, the specificity of NRS2002 is not high, but it can be used for evaluating nutritional deficiencies. MNA is a good nutritio
基金supported by the National Natural Science Foundation of China,No.81070971
文摘microRNAs （miRNAs） play an important regulatory role in the self-renewal and differentiation of stem cells. In this study, we examined the effects of miRNA-124 （miR-124） overexpression in bone marrow-derived mesenchymal stem cells. In particular, we focused on the effect of overexpression on the differentiation of bone marrow-derived mesenchymal stem cells into neurons. First, we used GeneChip technology to analyze the expression of miRNAs in bone marrow-derived mesen- chymal stem cells, neural stem cells and neurons, miR-124 expression was substantially reduced in bone marrow-derived mesenchymal stem cells compared with the other cell types. We con- structed a lentiviral vector overexpressing miR-124 and transfected it into bone marrow-derived mesenchymal stem cells. Intracellular expression levels of the neuronal early markers [3-III tu- bulin and microtubule-associated protein-2 were significantly increased, and apoptosis induced by oxygen and glucose deprivation was reduced in transfected cells. After miR-124-transfected bone marrow-derived mesenchymal stem cells were transplanted into the injured rat spinal cord, a large number of cells positive for the neuronal marker neurofilament-200 were observed in the transplanted region. The Basso-Beattie-Bresnahan locomotion scores showed that the motor function of the hind limb of rats with spinal cord injury was substantially improved. These re- sults suggest that miR-124 plays an important role in the differentiation of bone marrow-derived mesenchymal stem cells into neurons. Our findings should facilitate the development of novel strategies for enhancing the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for spinal cord injury.
文摘Background Hematopoietic stem cells （HSCs） give rise to all blood and immune cells and are used in clinical transplantation protocols to treat a wide variety of refractory diseases, but the amplification of HSCs has been difficult to achieve in vitro. In the present study, the expansive effects of aorta-gonad-mesonephros （AGM） region derived stromal cells on HSCs were explored, attempting to improve the efficiency of HSC transplantation in clinical practice.Methods The murine stromal cells were isolated from the AGM region of 12 days postcoitum （dpc） murine embryos and bone marrow（BM） of 6 weeks old mice, respectively. After identification with flow cytometry and immunocytochemistry, the stromal cells were co-cultured with ESCs-derived, cytokines-induced HSCs. The maintenance and expansion of ESCs-derived HSCs were evaluated by detecting the population of CD34^＋ and CD34^＋ Sca-1^＋ cells with flow cytometry and the blast colony-forming cells （BL-CFCs）, high proliferative potential colony-forming cells （HPP-CFCs） by using semi-solid medium colonial culture. Finally, the homing and hematopoietic reconstruction abilities of HSCs were evaluated using a murine model of HSC transplantation in vivo.Results AGM and BM-derived stromal cells were morphologically and phenotypically similar, and had the features of stromal cells. When co-cultured with AGM or BM stromal cells, more primitive progenitor cells （ HPP-CFCs ） could be detected in ESCs derived hematopoietic precursor cells, but BL-CFC＇ s expansion could be detected only when co-cultured with AGM-derived stromal cells. The population of CD34^＋ hematopoietic stem/ progenitor cells were expanded 3 times, but no significant expansion in the population of CD34^＋ Sca-1^＋ cells was noted when co-cultured with BM stromal cells. While both CD34^＋ hematopoietic stem/progenitor cells and CD34^＋ Sca-1^＋ cells were expanded 4 to 5 times respectively derived stromal cells, like BM-derived stromal cells, homing to BM in vivo. when co
基金supported by a grant from the Scientific Research Program of Liaoning Provincial Science and Technology Ministry in China,No.2012225014
文摘Because of their strong proliferative capacity and multi-potency, placenta-derived mesenchymal stem cells have gained interest as a cell source in the field of nerve damage repair. In the present study, human placenta-derived mesenchymal stem ceils were induced to differentiate into neural stem cells, which were then transplanted into the spinal cord after local spinal cord injury in rats. The motor functional recovery and pathological changes in the injured spinal cord were observed for 3 successive weeks. The results showed that human placenta-derived mesenchymal stem cells can differentiate into neuron-like cells and that induced neural stem cells contribute to the restoration of injured spinal cord without causing transplant rejection. Thus, these cells promote the recovery of motor and sensory functions in a rat model of spinal cord injury. Therefore, human placenta-derived mesenchymal stem cells may be useful as seed cells during the repair of spinal cord injury.
基金supported by a"KRCF National Agenda Project",by an Asan Life Science Institute Grant(12-241)from the Asan Medical Center,Seoul,Korea
文摘Transplantation of neural stem cells has been reported as a possible approach for replacing impaired dopaminergic neurons. In this study, we tested the efficacy of early-stage human dental papilla-derived stem cells and human brain-derived neural stem cells in rat models of 6-hydroxydopamine-induced Parkinson＇s disease. Rats received a unilateral injection of 6-hydroxydopamine into right medial forebrain bundle, followed 3 weeks later by injections of PBS, early-stage human dental papilla-derived stem cells, or human brain-derived neural stem cells into the ipsilateral striatum. All of the rats in the human dental papilla-derived stem cell group died from tumor formation at around 2 weeks following cell transplantation. Postmortem examinations revealed homogeneous malignant tumors in the striatum of the human dental papilla-derived stem cell group. Stepping tests revealed that human brain-derived neural stem cell transplantation did not improve motor dysfunction. In apomorphine-induced rotation tests, neither the human brain-derived neural stem cell group nor the control groups （PBS injection） demonstrated significant changes. Glucose metabolism in the lesioned side of striatum was reduced by human brain-derived neural stem cell transplantation. [18F]-FP-CIT PET scans in the striatum did not demonstrate a significant increase in the human brain-derived neural stem cell group. Tyrosine hydroxylase （dopaminergic neuronal marker） staining and G protein-activated inward rectifier potassium channel 2 （A9 dopaminergic neuronal marker） were positive in the lesioned side of striatum in the human brain-derived neural stem cell group. The use of early-stage human dental papilla-derived stern cells confirmed its tendency to form tumors. Human brain-derived neural stem cells could be partially differentiated into dopaminergic neurons, but they did not secrete dopamine.
基金financially supported by the National Natural Science Foundation of China(Grant No.51109131)
文摘In order to solve the severe vibration problems of an ocean engineering ship with a full-revolving propulsion system, the navigation tests, including forced vibration response test and modal test, are carded out in its stem. It is concluded from the comparison of the time-domain waveform and spectrum from different measurement points that three main factors lead to a high-level stern vibration. Firstly, the specific dynamic stiffness of a water tank is relatively small compared with its neighbor hold, which makes it act like a vibration isolator preventing vibrational energy transmitting to the main hold. Secondly, there exists high-density local modes in the working frequency range of the main engine and thus the local resonance occurs. Thirdly, the abnormal engagement of gears caused by the large deflection of the shaft bearing due to its low mounting rigidity leads to violent extra impulse excitations at high speeds. Then the modification against the dynamic defects is given by simply improving the specific stiffness of the water tanks. And the effect is validated by the FEM calculation. Some important experience is obtained with the problems being solved, which is useful in the design of ships with the same propulsion system. It is also believed that the dynamic consideration is as important as the static analysis for the ships, and that most of the vibration problems may be avoided with a proper acoustic design.
基金supported by a grant from Science and Technology Research Projects of Shanxi Province,No.20120321028-02a grant from the Scientific and Technical Foundation of Shanxi Provincial Health Department,No.201201067+1 种基金a grant from University Research and Development Projects of Shanxi Province,No.20131101grant from the National Natural Science Foundation of China,No.81371628
文摘In vitro experiments have demonstrated that neuronal-like cells derived from bone marrow mesen- chymal stem cells can survive, migrate, integrate and help to restore the function and behaviors of spinal cord injury models, and that they may serve as a suitable approach to treating spinal cord injury. However, it is very difficult to track transplanted cells in vivo. In this study, we injected su- perparamagnetic iron oxide-labeled neuronal-like cells into the subarachnoid space in a rabbit model of spinal cord injury. At 7 days after cell transplantation, a small number of dot-shaped low signal intensity shadows were observed in the spinal cord injury region, and at 14 days, the number of these shadows increased on T2-weighted imaging. Perl＇s Prussian blue staining detected dot-shaped low signal intensity shadows in the spinal cord injury region, indicative of superpara- magnetic iron oxide nanoparticle-labeled cells. These findings suggest that transplanted neu- ronal-like cells derived from bone marrow mesenchymal stem cells can migrate to the spinal cord injury region and can be tracked by magnetic resonance in vivo. Magnetic resonance imaging represents an efficient noninvasive technique for visually tracking transplanted cells in vivo.
文摘Glaucoma and other optic neuropathies result in optic nerve degeneration and the loss of retinal ganglion cells（RGCs）through complex signaling pathways.Although the mechanisms that regulate RGC development remain unclear,uncovering novel developmental pathways may support new strategies to regenerate the optic nerve or replace RGCs.Here we review recent studies that provide strong evidence that the Sry-related high-mobility-group C（SoxC）subfamily of transcription factors（TFs）are necessary and sufficient for axon guidance and RGC fate specification.These findings also uncover novel SoxC-dependent mechanisms that serve as master regulators during important steps of RGC development.For example,we review work showing that SoxC TFs regulate RGC axon guidance and direction through the optic chiasm towards their appropriate targets in the brain.We also review work demonstrating that Sox11 subcellular localization is,in part,controlled through small ubiquitin-like post-translational modifier（SUMO）and suggest compensatory cross-talk between Sox4 and Sox11.Furthermore,Sox4 overexpression is shown to positively drive RGC differentiation in human induced pluripotent stem cells（hi PSCs）.Finally,we discuss how these findings may contribute to the advancement of regenerative and cell-based therapies to treat glaucoma and other optic nerve neuropathies.
文摘The effects of vascular endothelial growth factor （VEGF） on neural differentiation of human embryonic stem cells （hESCs） in vitro and the possible mechanism were observed. The hESCs lines, TJMU1 and TJMU2, were established and stored by our laboratory, hESCs differentiated into neuronal cells through embryonic body formation. In this induction process, hESCs were divided into three groups： group A, routine induction; group B, routine induction＋10 ng/mL VEGF; group C, routine in- duction＋10 ng/mL VEGF＋10 ng/mL VEGFR2/Fc. OCT4, Nestin and GFAP in each group were de- tected by RT-PCR, and the cells expressing Nestin and GFAP were counted by immunofluorescence. The percentage of Nestin positive cells in group B was significantly higher than in groups A and C, while the percentage of GFAP positive cells in group B was significantly lower than in groups A and C （P〈0.01）. There was no significant difference between groups A and C （P〉0.05）. It was concluded that VEGF, via VEGFR2, stimulated the neural differentiation of hESCs in vitro.
基金This work was supported by the Ocean Systems Simulation and Control Laboratory(OSSCL)Consortium.
文摘The coupled level-set and volume of fluid(CLSVOF)method is an advanced interface-capturing method that has been extended to handle overset grid systems.However,artificial uneven interface may be observed across block boundaries of different sizes and geometries.We present an improved inter-grid VOF interpolation and mass correction scheme to address the issue.To demonstrate the capability of the improved CLSVOF method,it is applied to the simulation of a container ship in pitch and heave motions under both head sea and following sea irregular wave conditions.Our simulation proves that the improved CLSVOF method is capable of revealing detailed physics difficult to see with other methods.Those phenomena simulated in our work include the extensive greenwater propagation on the ship deck,the breakup of overtopping waves into small droplets,and the formation and collapse of air pockets in sudden bow and stern slamming which cause strong and highly localized impacts on the ship bow,stern,and rudder.
文摘Suitability of S-Glass/carbon fiber reinforced polymer composite for submarine hull subjected to hydrostatic pressure has been investigated in the present study.Metallic materials have raised concerns owing to their decomposition due to low resistance towards salinity and hence polymer composites have been explored to showcase their mechanical stability to withstand transverse and impact loads.To this end,the mechanical properties of S-Glass/carbon fiber reinforced polymer composite were experimentally investigated and higher specific strength and stiffness of the composite in comparison to many metallic materials used for submarine hull were reported.The obtained experimental values were used for the static and dynamic crash analysis of the bow,stern and foil through Finite Element Analysis(FEA);where depth of travel was varied from sea surface level of 0-7000 m.Submarine assembly was later developed with the optimum shape and thickness of each part.We also report the nonlinear crash analysis upon impact at velocity ranging from 3 to 21 m/s.Besides,kinetic energy,acceleration peak and internal energy in struck submarine revealed that travel depth 1750 m and 3500 m is recommendable,more particularly,crash safety factor of the submarine is found to be within limit when submarine encounters crash at 1750 m.
文摘The variations of ship stern flow field structure and its corresponding hydrodnamic performance under full scale Reynolds numbal (5 109) and model scale Reynolds numbal(5 106) are investigated numerically in this paper. The governing equations for 3-D incompressible turbulent flow which consist of RANS equation and K-ε two equation turbulence model are solved by finite difference scheme. Derailed computational results are presented graphically. The comparisons between present calculation, existing measurement and other calculation are made.
文摘In this paper the complex structure and pattern of ship stern flow driven by multi-propellers is simulated numerically by using RANS equations with K turbulence model and propeller lifting surface theory as essential research tool and coupling the computer code of ship stern flow to the computer code of propeller performance prediction through the medium of body force. A ship model with four propellers is selected as the numerical example. Detailed computational results are presented graphically and the qualitative and quantitative analysis is made. Finally,the comparison between the calculated result and the avaikble experimental data is made. The agreement between them is satisfac-
文摘Orlic et al treated mice （splenectomized two weeks ago） with granulocyte colony stimulating factor （G-CSF） and stem cell factor （SCF） for five days before acute myocardium infarction （AMI） and three days after AMI. They found that those treatments could repair infarcted hearts, improve heart performance and decrease mortality. However, from the clinical standpoint, the work of Orlic and his co-workers has an obvious limitation.
