By using the first-principles calculations, the electronic Structure and quantum transport properties of metallic carbon nanotubes with B/N pairs co-doping have been investigated. It is shown that the total energies o...By using the first-principles calculations, the electronic Structure and quantum transport properties of metallic carbon nanotubes with B/N pairs co-doping have been investigated. It is shown that the total energies of metallic carbon nanotubes are sensitive to the doping sites of the B/N pairs. The energy gaps of the doped metallic carbon nanotubes decrease with decreasing the concentration of the B/N pair not only along the tube axis but also around the tube. Moreover, the I-V characteristics and transmissions of the doped tubes are studied. Our results reveal that the conducting ability of the doped tube decreases with increasing the concentrations of the B/N pairs due to symmetry breaking of the system. This fact opens a new way to modulate band structures of metallic carbon nanotubes by doping B/N pair with suitable concentration and the novel characteristics are potentially useful in future applications.展开更多
The iron rhenate was compounded by chemical method, whichmay be generated during wear process of FeRe alloys at elevated temperature. The friction coefficient of iron rhenate has been determined by a pinondisc device....The iron rhenate was compounded by chemical method, whichmay be generated during wear process of FeRe alloys at elevated temperature. The friction coefficient of iron rhenate has been determined by a pinondisc device. The results show that iron rhenate plays role of lubricating at RT600 ℃. The lubricating behavior is related to the matching pairs. The hardness of the materials of matching pairs, compatibility of iron rhenate with materials of matching pairs and surface roughness of disc affect the lubricating behavior of iron rhenate mostly. The principle of matching pairs is proposed.展开更多
Regenerative capacity is weak after central nervous system injury because of the absence of an enhancing microenvironment and presence of an inhibitory microenvironment for neuronal and axonal repair. In addition to t...Regenerative capacity is weak after central nervous system injury because of the absence of an enhancing microenvironment and presence of an inhibitory microenvironment for neuronal and axonal repair. In addition to the Nogo receptor（Ng R）, the paired immunoglobulin-like receptor B（Pir B） is a recently discovered coreceptor of Nogo, myelin-associated glycoprotein, and myelin oligodendrocyte glycoprotein. Concurrent blocking of Ng R and Pir B almost completely eliminates the inhibitory effect of myelin-associated inhibitory molecules on axonal regeneration. Pir B participates in a key pathological process of the nervous system, specifically axonal regeneration inhibition. Pir B is an inhibitory receptor similar to Ng R, but their effects are not identical. This study summarizes the structure, distribution, relationship with common nervous system diseases, and known mechanisms of Pir B, and concludes that Pir B is also distributed in cells of the immune and hematopoietic systems. Further investigations are needed to determine if immunomodulation and blood cell migration involve inhibition of axonal regeneration.展开更多
Paired immunoglobulin-like receptor B（Pir B） is a functional receptor of myelin-associated inhibitors for axonal regeneration and synaptic plasticity in the central nervous system, and thus suppresses nerve regenera...Paired immunoglobulin-like receptor B（Pir B） is a functional receptor of myelin-associated inhibitors for axonal regeneration and synaptic plasticity in the central nervous system, and thus suppresses nerve regeneration. The regulatory effect of Pir B on injured nerves has received a lot of attention. To better understand nerve regeneration inability after spinal cord injury, this study aimed to investigate the distribution of Pir B（via immunofluorescence） in the central nervous system and peripheral nervous system 10 days after injury. Immunoreactivity for Pir B increased in the dorsal root ganglia, sciatic nerves, and spinal cord segments. In the dorsal root ganglia and sciatic nerves, Pir B was mainly distributed along neuronal and axonal membranes. Pir B was found to exhibit a diffuse, intricate distribution in the dorsal and ventral regions. Immunoreactivity for Pir B was enhanced in some cortical neurons located in the bilateral precentral gyri. Overall, the findings suggest a pattern of Pir B immunoreactivity in the nervous system after unilateral spinal transection injury, and also indicate that Pir B may suppress repair after injury.展开更多
对分布于我国不同地区的冰草属(Agropyron Gaertn.)4个种的33份材料进行了花粉母细胞减数分裂期染色体行为观察。发现含 B 染色体的材料主要集中在沙芦草(A.mongolicumKeng,2n=2x=14)中。在沙生冰草(A.deseriorum〈Fi sch.〉Schult.,2n=...对分布于我国不同地区的冰草属(Agropyron Gaertn.)4个种的33份材料进行了花粉母细胞减数分裂期染色体行为观察。发现含 B 染色体的材料主要集中在沙芦草(A.mongolicumKeng,2n=2x=14)中。在沙生冰草(A.deseriorum〈Fi sch.〉Schult.,2n=4x=28)中有40%的材料含 B 染色体。而在四倍体冰草(A.cristatum〈L.〉Gaertn.,2n=4x=28)和根茎冰草(A.michnoi Roshev.,2n=4x=28)中未找到含 B 染色体的材料。偶数 B 染色体间的配对通常发生在终变期,而奇数 B 染色体间的配对通常在中期 I。B 染色体在后期 I的分离是随机的。落后 B 染色体的分离,一般是通过本身的提前分裂以染色单体的形式趋向两极。含有较高数目的 B 染色体有提高 A 染色体间配对和交叉频率的作用。讨论了 B 染色体的存在与倍性水平间的关系以及 B 染色体间的同源性等问题。展开更多
基金supported by the Major Research Plan from the Ministry of Science and Technology of China (Grant No. 2011CB921900)the China Postdoctoral Science Special Foundation (Grant No. 201003009)+2 种基金the China Postdoctoral Science Foundation (GrantNo. 20090460145)the Fundamental Research Funds for the Central Universities (Grant No. 201012200053)the Science and Technology Program of Hunan Province of China (Grant No. 2010DFJ411)
文摘By using the first-principles calculations, the electronic Structure and quantum transport properties of metallic carbon nanotubes with B/N pairs co-doping have been investigated. It is shown that the total energies of metallic carbon nanotubes are sensitive to the doping sites of the B/N pairs. The energy gaps of the doped metallic carbon nanotubes decrease with decreasing the concentration of the B/N pair not only along the tube axis but also around the tube. Moreover, the I-V characteristics and transmissions of the doped tubes are studied. Our results reveal that the conducting ability of the doped tube decreases with increasing the concentrations of the B/N pairs due to symmetry breaking of the system. This fact opens a new way to modulate band structures of metallic carbon nanotubes by doping B/N pair with suitable concentration and the novel characteristics are potentially useful in future applications.
基金the NationalNatural+3 种基金 Science Foundation of China
文摘The iron rhenate was compounded by chemical method, whichmay be generated during wear process of FeRe alloys at elevated temperature. The friction coefficient of iron rhenate has been determined by a pinondisc device. The results show that iron rhenate plays role of lubricating at RT600 ℃. The lubricating behavior is related to the matching pairs. The hardness of the materials of matching pairs, compatibility of iron rhenate with materials of matching pairs and surface roughness of disc affect the lubricating behavior of iron rhenate mostly. The principle of matching pairs is proposed.
基金supported by the National Natural Science Foundation of China,No.81170577
文摘Regenerative capacity is weak after central nervous system injury because of the absence of an enhancing microenvironment and presence of an inhibitory microenvironment for neuronal and axonal repair. In addition to the Nogo receptor（Ng R）, the paired immunoglobulin-like receptor B（Pir B） is a recently discovered coreceptor of Nogo, myelin-associated glycoprotein, and myelin oligodendrocyte glycoprotein. Concurrent blocking of Ng R and Pir B almost completely eliminates the inhibitory effect of myelin-associated inhibitory molecules on axonal regeneration. Pir B participates in a key pathological process of the nervous system, specifically axonal regeneration inhibition. Pir B is an inhibitory receptor similar to Ng R, but their effects are not identical. This study summarizes the structure, distribution, relationship with common nervous system diseases, and known mechanisms of Pir B, and concludes that Pir B is also distributed in cells of the immune and hematopoietic systems. Further investigations are needed to determine if immunomodulation and blood cell migration involve inhibition of axonal regeneration.
基金supported by the National Natural Science Foundation of China,No.81171178the Natural Science Foundation of Shanxi Province in China,No.2012011036-3the Research Project of Shanxi Scholarship Council of China,No.2012-047
文摘Paired immunoglobulin-like receptor B（Pir B） is a functional receptor of myelin-associated inhibitors for axonal regeneration and synaptic plasticity in the central nervous system, and thus suppresses nerve regeneration. The regulatory effect of Pir B on injured nerves has received a lot of attention. To better understand nerve regeneration inability after spinal cord injury, this study aimed to investigate the distribution of Pir B（via immunofluorescence） in the central nervous system and peripheral nervous system 10 days after injury. Immunoreactivity for Pir B increased in the dorsal root ganglia, sciatic nerves, and spinal cord segments. In the dorsal root ganglia and sciatic nerves, Pir B was mainly distributed along neuronal and axonal membranes. Pir B was found to exhibit a diffuse, intricate distribution in the dorsal and ventral regions. Immunoreactivity for Pir B was enhanced in some cortical neurons located in the bilateral precentral gyri. Overall, the findings suggest a pattern of Pir B immunoreactivity in the nervous system after unilateral spinal transection injury, and also indicate that Pir B may suppress repair after injury.
文摘对分布于我国不同地区的冰草属(Agropyron Gaertn.)4个种的33份材料进行了花粉母细胞减数分裂期染色体行为观察。发现含 B 染色体的材料主要集中在沙芦草(A.mongolicumKeng,2n=2x=14)中。在沙生冰草(A.deseriorum〈Fi sch.〉Schult.,2n=4x=28)中有40%的材料含 B 染色体。而在四倍体冰草(A.cristatum〈L.〉Gaertn.,2n=4x=28)和根茎冰草(A.michnoi Roshev.,2n=4x=28)中未找到含 B 染色体的材料。偶数 B 染色体间的配对通常发生在终变期,而奇数 B 染色体间的配对通常在中期 I。B 染色体在后期 I的分离是随机的。落后 B 染色体的分离,一般是通过本身的提前分裂以染色单体的形式趋向两极。含有较高数目的 B 染色体有提高 A 染色体间配对和交叉频率的作用。讨论了 B 染色体的存在与倍性水平间的关系以及 B 染色体间的同源性等问题。
