期刊文献+
共找到70篇文章
< 1 2 4 >
每页显示 20 50 100
Immunoelectron microscopic localization of calmodulin in corn root cells 被引量:14
1
作者 LIJIAXU JIEWENLIU DAYESUN 《Cell Research》 SCIE CAS CSCD 1993年第1期10-10,12-19,共9页
Methods for the localization of plant calmodulin by immuno-gold and immuno-peroxidase electron microscopy have been developed. In both corn root-cap cells and meristematic cells, calmodulin was found to be localized i... Methods for the localization of plant calmodulin by immuno-gold and immuno-peroxidase electron microscopy have been developed. In both corn root-cap cells and meristematic cells, calmodulin was found to be localized in the nucleus, cytoplasm, mitochondria as well as in the cell wall, In the meristematic cells, calmodulin was distinctly localized on the plasma membrane, cytoplasmic face of rough endoplasmic rcticulum and polyribosomes. Characteristically, calmodulin was present in the amyloplasts of root-cap cells. The widespread distribution of calmodulin may reflect its plciotropic functions in plant cellular activities. 展开更多
关键词 玉米 根细胞 电子显微镜 免疫定位 钙调蛋白 钙调素
下载PDF
Changes of microvascular architecture,ultrastructure and permeability of rat jejunal villi at different ages 被引量:11
2
作者 Yan-MinChen Jin-ShengZhang Xiang-LinDuan 《World Journal of Gastroenterology》 SCIE CAS CSCD 2003年第4期795-799,共5页
AIM: To investigate the changes of microvascular architecture, ultrastructure and permeability of rat jejunal villi at different ages.METHODS: Microvascular corrosion casting, scanning electron microscopy, transmissio... AIM: To investigate the changes of microvascular architecture, ultrastructure and permeability of rat jejunal villi at different ages.METHODS: Microvascular corrosion casting, scanning electron microscopy, transmission electron microscopy and Evans blue infiltration technique were used in this study.RESULTS: The intestinal villous plexus of adult rats consisted of arterioles, capillary network and venules. The marginal capillary extended to the base part of the villi and connected to the capillary networks of adjacent villi. In newborn rats,the villous plexus was rather simple, and capillary network was not formed. The villous plexus became cone-shaped and was closely arrayed in ablactation rats. In adult rats,the villous plexus became tongue-shaped and was enlarged both in height and width. In aged rats, the villous plexus shrank in volume and became shorter and narrower. The diametral ratio of villous arteriole to villous venule increased as animals became older. The number of endothelial holes,the thickness of basal membrane and the permeability of microvasculature were increased over the entire course of development from newborn period to aged period.CONCLUSION: The digestive and absorptive functions of the rat jejunum at different ages are highly dependent upon the state of villous microvascular architecture and permeability, and blood circulation is enhanced by collateral branches such as marginal capillary, through which blood is drained to the capillary networks of adjacent villi. 展开更多
关键词 空肠茸毛 微血管体系 超微结构 血管渗透性 年龄 大鼠 消化道疾病
下载PDF
Probabilistic Teleportation of Two—Particle State of General Formation 被引量:11
3
作者 YANFeng-Li TANHong-Ge 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第6期649-654,共6页
A scheme for probabilistic teleporting an unknown two-particle state of general formation by partly pure entangled four-particle state is proposed. It is shown that after performing two Bell state measurements, proper... A scheme for probabilistic teleporting an unknown two-particle state of general formation by partly pure entangled four-particle state is proposed. It is shown that after performing two Bell state measurements, proper unitary transformation and the measurement on an auxiliary qubit, the unknown two-particle state of general formation, which was destroyed at one place, can be reconstructed at another place with certain probability. 展开更多
关键词 量子力学 二粒子态 远距传物
下载PDF
Platinum-polyaniline-modified carbon fiber electrode for the electrooxidation of methanol 被引量:9
4
作者 WUKezhong MENGXu +1 位作者 WANGXindong LIJingling 《Rare Metals》 SCIE EI CAS CSCD 2005年第1期33-36,共4页
Platinum was electrodeposited onto a polyaniline-modified carbon fiberelectrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in thelevel of platinum utilization currently achieved i... Platinum was electrodeposited onto a polyaniline-modified carbon fiberelectrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in thelevel of platinum utilization currently achieved in electrocatalytic systems. This electrodepreparation consists of a two-step procedure: first electropolymerization of aniline onto carbonfiber and then electrodeposition of platinum. The catalytic activity of theplatinum-polyanihne-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a barecarbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current ofmethanol on Pt/PAni/C is 50.7 mA centre dot cm^(-2), which is 6.7 times higher than 7.6 mA centredot cm^(-2) on the Pt/C. Scanning electron microscopy was used to investigate the dispersion of theplatinum particles of about 0.4 um. 展开更多
关键词 physical chemistry ELECTRODEPOSITION POLYANILINE catalytic oxidation platinum utilization
下载PDF
Effects of extracellular iron concentration on calcium absorption and relationship between Ca^(2+) and cell apoptosis in Caco-2 cells 被引量:5
5
作者 LiWang QingLi Xiang-LinDuan Yan-ZhongChang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第19期2916-2921,共6页
AIM: To determine the method of growing small intestinal epithelial cells in short-term primary culture and to investigate the effect of extracellular iron concentration ([Fe3+]) on calcium absorption and the relation... AIM: To determine the method of growing small intestinal epithelial cells in short-term primary culture and to investigate the effect of extracellular iron concentration ([Fe3+]) on calcium absorption and the relationship between the rising intracellular calcium concentration ([Ca2+]i) and cell apoptosis in human intestinal epithelial Caco-2 cells. METHODS: Primary culture was used for growing small intestinal epithelial cells. [Ca2+]i was detected by a confocal laser scanning microscope. The changes in [Ca2+]i were represented by fluorescence intensity (FI). The apoptosis was evaluated by flow cytometry.RESULTS: Isolation of epithelial cells and preservation of its three-dimensional integrity were achieved using the digestion technique of a mixture of collagenase Ⅺ and dispase Ⅰ. Purification of the epithelial cells was facilitated by using a simple differential sedimentation method. The results showed that proliferation of normal gut epithelium in vitro was initially dependent upon the maintenance of structural integrity of the tissue. If 0.25% trypsin was used for digestion, the cells were severely damaged and very difficult to stick to the Petri dish for growing. The Fe3+ chelating agent desferrioxamine (100, 200 and 300 μmol/L) increased the FI of Caco-2 cells from 27.50±13.18 (control,n = 150) to 35.71±13.99 (n = 150, P<0.01), 72.19±35.40 (n = 150, P<0.01) and 211.34±29.03 (n = 150, P<0.01) in a concentration-dependent manner. There was a significant decrease in the FI of Caco-2 cells treated by ferric ammonium citrate (FAC, a Fe3+ donor; 10, 50 and 100 μmol/L). The FIvalue of Caco-2 cells treated by FAC was 185.85±33.77 (n = 150, P<0.01), 122.73±58.47 (n = 150, P<0.01), and 53.29±19.82 (n = 150, P<0.01), respectively, suggesting that calcium absorption was influenced by [Fe3+]. Calcium ionophore A23187 (0.1, 1.0 and 10 μmol/L) increased the FI of Caco-2 cells from 40.45±13.95 (control, n = 150) to 45.19±21.95 (n = 150, P<0.01), 89.87±43.29 (n = 150,P<0.01) and 104.64±51.07 (n = 150, P<0.01) in a concentration-dependent manner. The positive apoptotic cell number of the Caco-2 cells after being treated with indicating that the increase in the positive apoptotic cell~ increased from 0.32% to 0.69%, 0.90% and 1.10%, number was positively correlated with [Ca2+]i.CONCLUSION: Ca2+ absorbability is increased with the decrease of extracellular iron concentration Fe3+ and hindered with the increase of Fe3+ consistence out of them. Furthermore, increase of [Ca2+]i can induce apoptosis in Caco-2 cells. 展开更多
关键词 细胞外浓缩 钙元素 吸收作用 细胞凋亡 CACO-2 小肠疾病
下载PDF
Probabilistic Teleportation of One-Particle State of S-level 被引量:5
6
作者 YANFeng-Li BAIYan-Kui 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第3X期273-278,共6页
A scheme for probabilistically teleporting an unknown one-particle state of S-level by a group of pairs of partially entangled 2-level particle state is proposed. In this scheme unitary transformation and local measu... A scheme for probabilistically teleporting an unknown one-particle state of S-level by a group of pairs of partially entangled 2-level particle state is proposed. In this scheme unitary transformation and local measurement take the place of Bell state measurement, then proper unitary transformation and the measurement on an auxiliary qubit with the aid of classical communication are performed. In this way the unknown one-particle state of S-level can be transferred onto a group of remote 2-level particles with certain probability. Furthermore, the receiver can recover the initial signal state on an S-level particle at his hand. 展开更多
关键词 直接傅里叶变换 概率输运 二阶粒子态 量子输运 量子态 量子论 局部测量
下载PDF
Distribution of constitutive nitric oxide synthase in the jejunum of adult rat 被引量:6
7
作者 ChenYM QianZM 《World Journal of Gastroenterology》 SCIE CAS CSCD 2002年第3期537-539,共3页
AIM:To study the distribution of the constitutive nitric oxide synthase(NOS) in the jejunom of adult rat.METHODS:The distribution of endothelial NOS(eNOS) was detected by immunohistochemistry.Immunofluorescence histo... AIM:To study the distribution of the constitutive nitric oxide synthase(NOS) in the jejunom of adult rat.METHODS:The distribution of endothelial NOS(eNOS) was detected by immunohistochemistry.Immunofluorescence histochemical dual stainging technique were used for studying the distribution of neuronal NOS( nNOS) and eNOS,The dual stained slides were observed under a confocal laser scanning microscope.RESULTS:Positive neuronal NOS(nNOS) and endothelial NOS(eNOS) cells were found to be distributed in lamina propria of villi,and the epithelial cell was not stained,eNOS was mainly located in submucosal vascular endothelia while nNOS was mainly sityated in myenteric plexus.Some cells in the villi had both nNOS and eNOS.More than 80% of the cells were positive for both nNOS and eNOS,the rest cells were positive either for nNOS or for eNOS.CONCLUSION:The two constitutive nitric oxide synthases are distributed differently in the jejunum of rat.nNOS distributed in myenteric plexus is a neurotransmitter in the non-adrenergic non-cholinergic(NANC)inhibitory nerves eNOS distributed in endothelial and smooth muscle cells of blood vessels plays vasodilator role .eNOS and nNOS are coexpressed in some cells of lamina propria of villi.NO genearted y those NOS is very important in the physiological and pathological process of small intestine. 展开更多
关键词 空肠 一氧化氮合酶 分布 成年鼠
下载PDF
Crystal structure and properties of terbium o-methylbenzoate complex with 1,10-phenanthroline [Tb(o-CH_3C_6H_4COO)_3(C_(12)H_8N_2)]_2 被引量:3
8
作者 WANGRuifen WANGShuping +1 位作者 SHIShikao ZHANGJianjun 《Rare Metals》 SCIE EI CAS CSCD 2004年第2期103-108,共6页
A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb(o-MBA)_3phen(where o-MBA = o-methylbenzoate and phen = 1,10-phenanthroline) was prepared from ethanol solutionand its crystal structure was determined by... A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb(o-MBA)_3phen(where o-MBA = o-methylbenzoate and phen = 1,10-phenanthroline) was prepared from ethanol solutionand its crystal structure was determined by X-ray diffraction. The crystal of the complexTb(o-MBA)_3phen belongs to triclinic crystal system and P1 (#2) space group. The crystal data are asfollows: a = 1.4371(4) nm, b = 1.7387(2) nm, c = 1.3109(2) nm, α = 96.37(1)°, β = 107.21(2)°,γ= 82.78(2)°, Ⅴ= 3.094(1) nm^3, Z= 2, M_r = 1489.12, D_c= 1.598 g·cm^(-3), μ = 2.330 mm^(-1)and F(000) = 1488.00. The final R and R_w are 0.038 and 0.047 for 8668 [Ⅰ > 2σ(Ⅰ)] uniquereflections, respectively. In the complex each Tb^(3+) ion is eight-coordinated by one1,10-phenanthroline molecule, one bidentate carboxylate group and four bridging carboxylate groups.The carboxylate groups are bonded to the terbium ion in two modes: the chelating bidentate and thebridging bidentate. Excitation and luminescence data observed at room temperature show that thetitle complex emits strong green fluorescence under ultraviolet light. The results of thermalanalysis indicate that the complex Tb(o-MBA)_3phen is quite stable to heat. 展开更多
关键词 inorganic chemistry crystal structure X-ray analysis terbium complex o-methylbenzoic acid 1 10-PHENANTHROLINE luminescence
下载PDF
Thermal Decomposition Mechanism and Non Isothermal Kinetics of Complex of [La_2(P-MBA)_6(PHEN)_2]2H_2O 被引量:3
9
作者 张建军 王瑞芬 +1 位作者 白继海 王淑萍 《Journal of Rare Earths》 SCIE EI CAS CSCD 2002年第5期449-452,共4页
The complex of [La 2(P MBA) 6(PHEN) 2]2H 2O (P MBA: p methylbenzoate and PHEN: 1,10 phenanthroline) was prepared and characterized by elemental analysis and IR spectroscopy. The thermal behavior of [La 2(P M... The complex of [La 2(P MBA) 6(PHEN) 2]2H 2O (P MBA: p methylbenzoate and PHEN: 1,10 phenanthroline) was prepared and characterized by elemental analysis and IR spectroscopy. The thermal behavior of [La 2(P MBA) 6(PHEN) 2]2H 2O in dynamic nitrogen atmosphere was investigated by TG DTG techniques. The results show that the thermal decomposition process of the [La 2(P MBA) 6(PHEN) 2]2H 2O occurs in five steps. The empirical kinetic model for the first step thermal decomposition obtained by Malek method is SB(m,n). The activation energy E and the pre exponential factor lnA for this step reaction are 76.4 kJ·mol -1 and 24.92, respectively. 展开更多
关键词 rare earths lanthanum complex non isothermal kinetics P methylbenzoic acid thermal decomposition TG DTG
下载PDF
Isolation and Characterization of the Wheat cDNA Fragments Involved in Salt Stress 被引量:5
10
作者 MAWen-shi Gui-ping +1 位作者 SHENYin-zhu HUANGZhan-jing 《Agricultural Sciences in China》 CAS CSCD 2004年第3期173-177,共5页
cDNA-AFLP(amplified fragment length polymorphism) is used to isolate genes differentiallyexpressed in salt-stressed and unstressed wheat lines RH8706-49 and H8706-34 derivedfrom a single seed, representing a salt-stre... cDNA-AFLP(amplified fragment length polymorphism) is used to isolate genes differentiallyexpressed in salt-stressed and unstressed wheat lines RH8706-49 and H8706-34 derivedfrom a single seed, representing a salt-stress resistant (SR) and salt-stress sensitive(SS) line, respectively. About 88.1% cDNA fragment are expressed in all the four samples,11.9% are different between the samples. 68 cDNA fragments were cloned, of which 35 weresubject to sequence analysis. Database searches indicate that 11 cDNA fragment show highhomology to known genes, which mainly include proteins related to ion transport, signaltransduction and oxidative stress. The remaining 24 cDNA show no detectable homology toknown genes, suggesting that they probably represent novel genes. 展开更多
关键词 Common wheat CDNA-AFLP Salt stress MUTANT
下载PDF
Synchronization and Asynchronization in Two Coupled Excitable Systems 被引量:4
11
作者 YUANGuo-Yong ZHANGGuang-Cai +1 位作者 WANGGuang-Rui CHENShi-Gang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第3期459-465,共7页
The synchronization and asynchronization of two coupled excitable systems are investigated. The two systems with different initial configurations, which are separately a single spiral wave (or a travel wave) and the r... The synchronization and asynchronization of two coupled excitable systems are investigated. The two systems with different initial configurations, which are separately a single spiral wave (or a travel wave) and the rest state, can be developed to the synchronizing state with the same spiral wave (or travel wave) in each system, when the coupling is very strong. Decreasing the coupling intensity, two rest states or two different configurations appear in the two systems. The qualitative analysis and interpretation are given. 展开更多
关键词 应激系统 空间波 时间同步 混沌 耦合模型
下载PDF
Non-isothermal decomposition kinetics and lifetime of Tb2(0-MBA)6(PHEN)2 被引量:3
12
作者 ZHANGJianjun BAIJihai +2 位作者 WANGRuifen WANGShuping LIJibiao 《Rare Metals》 SCIE EI CAS CSCD 2003年第3期155-159,共5页
The thermal decomposition of Tb_2(O-MBA)_6(PHEN)_2 (O-MBA: o-methylbenzoate;PHEN: 1,10-phenanthroline) and its kinetics were studied under the non-isothermal condition bythermogravimetry-derivative thermogravimetry (T... The thermal decomposition of Tb_2(O-MBA)_6(PHEN)_2 (O-MBA: o-methylbenzoate;PHEN: 1,10-phenanthroline) and its kinetics were studied under the non-isothermal condition bythermogravimetry-derivative thermogravimetry (TG-DTG) techniques. Kinetic parameters were obtainedfrom analysis of TG-DTG curves by the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method.The most probable mechanism function was suggested by comparing the kinetic parameters. The kineticequation for the first stage can be expressed as dα/dt = Aexp(-E/RT)·3(1 - α)^(2/3). Thelifetime equation at mass loss of 10% was deduced as lnτ= -28.7429 + 19797.795/T by isothermalthermogravimetric analysis. 展开更多
关键词 thermochimica non-isothermal kinetics TG-DTG terbium complex O-methylbenzoate 1 10-PHENANTHROLINE
下载PDF
Transglutaminase 3 expression in C57BL/6J mouse embryo epidermis and the correlation with its differentiation 被引量:3
13
作者 JianZHANG HuiYingZHI +2 位作者 FangDING AiPingLUO ZhiHuaLIU 《Cell Research》 SCIE CAS CSCD 2005年第2期105-110,共6页
Epidermal-type transglutaminase 3 (TGM3) is involved in the cross-linking of structural proteins to form the cornifiedenvelope in the epidermis. In the present study, we detected the expression of TGM3 in the mouse em... Epidermal-type transglutaminase 3 (TGM3) is involved in the cross-linking of structural proteins to form the cornifiedenvelope in the epidermis. In the present study, we detected the expression of TGM3 in the mouse embryo using RT-PCR.TGM3 mRNA is weakly presented from E11.5 to E14.5 and increases significantly from E15.5 to birth. Then wedetermined the spatial and temporal expression pattern of TGM3 in the skin and other organs by in situ hybridization. Wefound a deprivation of TGM3 in skin at E11.5, while a rich supply in periderm cells and a weak expression in basal cellsfrom E12.5 to E14.5. From the period of E15.5 to E16.5, after keratinization in the epidermis, TGM3 was expressed inthe granular and cornified layers. The electron microscopic observation of the C57BL/6J mouse limb bud skin develop-ment provided several morphological evidences for the epidermal differentiation. The above findings suggest that theexpression of TGM3 plays a important role in the epidermis differentiation in embryogenesis. 展开更多
关键词 谷氨酰胺转移酶3 相关分析 表皮细胞 差异表达 C57BL/6J老鼠胚胎
下载PDF
THE GLOBAL APPROXIMATION BY LEFT-BERNSTEIN-DURRMEYER QUASI-INTERPOLANTS IN Lp[0,1] 被引量:3
14
作者 DuanLiqin LiCuixiang 《Analysis in Theory and Applications》 2004年第3期242-251,共10页
In this paper, we will use the 2r-th Ditzian-Totik modulus of smoothness wψ2r(f,t)p to discuss the direct and inverse theorem of approximation by Left-Bernstein-Durrmeyer quasi-interpolants Mn[2r-1]f for functions of... In this paper, we will use the 2r-th Ditzian-Totik modulus of smoothness wψ2r(f,t)p to discuss the direct and inverse theorem of approximation by Left-Bernstein-Durrmeyer quasi-interpolants Mn[2r-1]f for functions of the space Lp[0,1] (1≤ p≤ +∞). 展开更多
关键词 direct and inverse theorem left-Bernstein-Durrmeyer quasi-interpolants modulus of smoothness
下载PDF
Thermal decomposition kinetics and lifetime of the complex of Tb_2(BA)_6(PHEN)_2 被引量:2
15
作者 ZHANGJianjun WANGRuifen +3 位作者 WANGShuping LIUHongmei LIJibiao BAIJihai 《Rare Metals》 SCIE EI CAS CSCD 2004年第2期126-130,共5页
The thermal behavior of Tb_2(BA)_6(PHEN)_2 (BA: benzoate, and PHEN:1,10-phenanthroline) in a static air atmosphere was investigated by TG-DTG, SEM and IR techniques.By the kinetic method of processing thermal analysis... The thermal behavior of Tb_2(BA)_6(PHEN)_2 (BA: benzoate, and PHEN:1,10-phenanthroline) in a static air atmosphere was investigated by TG-DTG, SEM and IR techniques.By the kinetic method of processing thermal analysis data put forward by Malek et al., it is definedthat the kinetic model for the first-step thermal decomposition is SB(m, n). The activation energyE for this step reaction is 99.07 kJ/mol, the entropy of activation ΔS~≠ is -84.72 J/mol, theenthalpy of activation ΔH~≠ is 94.26 kJ/mol, the free energy of activation ΔG~≠ is 144.77 kJ/moland the pre-exponential factor lnA is 20.93. The lifetime equation at mass-loss of 10% was deducedas lnτ = -29.0312 + 19760.83/T by isothermal thermogravimetric analysis. 展开更多
关键词 LIFETIME KINETICS benzoic acid terbium complex thermal decomposition
下载PDF
Synthesis and Crystal Structure of α-( N-Protected a mino)β-lactam Derivative of 1 ,5-Benzothiazepine 被引量:2
16
作者 李媛 金声 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 1999年第5期331-334,共4页
The crystal of the title compound C, C 30 H 30 N 2O 3S has been prepared by reaction of 1,5 benzothiazepine with N protected glycine and determined by X ray single crystal diffraction. Crystal data:... The crystal of the title compound C, C 30 H 30 N 2O 3S has been prepared by reaction of 1,5 benzothiazepine with N protected glycine and determined by X ray single crystal diffraction. Crystal data: M r =498.62, triclinic with P 1 space group, a=10.880(2), b=13.955(3), c=9.537(2), α=99.34(3)°, β=110.43(3)°, γ=88 56(3)°, V=1338.2(5) 3, F(000)=528, λ (Mo Kα)=0.71073, Z=2, D c =1 237g/cm 3, μ =0.154mm -1 . Final R=0.0453, wR =0.1256 for 3491 observed reflections 〔 I>2σ(I) 〕. Structure analysis reveals that the substituents at C(23) and C(7) in four membered ring are located on the same side. The conformation of seven membered ring is chair like. 展开更多
关键词 crystal structure cycloaddition reaction β lactam 1 5 benzothiazepine.
下载PDF
Microscopic Theory of Blue Phases Ⅰ and Ⅱ of Liquid Crystal 被引量:1
17
作者 LIUJian-Jun YANGGuo-Chen SHENMan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第1X期131-140,共10页
The microscopic theory of the blue phases of chiral liquid crystal is proposed. Beginning with the potential between two molecules, by using the cell model of liquid, applying statistical physical method, the distribu... The microscopic theory of the blue phases of chiral liquid crystal is proposed. Beginning with the potential between two molecules, by using the cell model of liquid, applying statistical physical method, the distribution function and the free energy of the system are obtained. By using variational approach and zero-order approximation, the differential equation that the order parameter tensor of the blue phase can satisfy is obtained. Then we change the differential equation to the eigenequation problem in quantum mechanics. Considering the symmetry of the blue phases,the order parameter tensors of blue phases Ⅰ and Ⅱ can be made up of the eigenvectors. Our results are the same as the results of Ginzberg-Landau's phenomenological theory. The parameters in the order parameter tensors that we calculate in the located system are close to the predecessors' results. 展开更多
关键词 液晶 蓝色位相 手性特征 统计物理 分布函数 变量分离
下载PDF
Contruction of the Genetic Engineering Strain Expressed Nontoxic ST_1-LT_B Fusion Protein Against Enterotoxigenic Eschenichia coli 被引量:1
18
作者 BAIJia-ning SUNYi-min BIANYan-qing ZHAOBao-hua 《Agricultural Sciences in China》 CAS CSCD 2004年第7期535-540,共6页
Thermostable enterotoxinⅠ(ST1) mutant genes and thermolabile enterotoxin B subunit (LTB)genes were amplified by PCR from plasmids of Eschenichia coli C83902. The recombinantexpression plasmid pZST3LTB containing ST1-... Thermostable enterotoxinⅠ(ST1) mutant genes and thermolabile enterotoxin B subunit (LTB)genes were amplified by PCR from plasmids of Eschenichia coli C83902. The recombinantexpression plasmid pZST3LTB containing ST1-LTB fusion gene was constructed by recombinantDNA technique and then transformed into Escherichia coli BL21(DE3). The ST1-LTB fusionprotein was highly expressed in recombinant strain BL21(DE3)(pZST3LTB) and the fusionprotein was about 38.53% of total cellular protein by SDS-PAGE and thin-layer gelscanning analysis. More important, mice immunized with crude preparation containing thefusion protein inclusion bodies or inactivated recombinant strain produced antibodiesthat were able to recognize ST1 in vitro. These sera antibodies were able to neutralizethe biological activity of native ST1 in the suckling mouse assay. Hence the ST1-LTBfusion protein was nontoxic and immunogenic, the constructed recombinant strain BL21(DE3)(pZST3LTB) could be used as a candidate of vaccine strain. 展开更多
关键词 Thermostable enterotoxinⅠgene Thermolabile enterotoxin B subunit gene Fusion GENE Fusion protein Gene expression
下载PDF
Thermal stability and luminescence properties of 1,10-phenanthroline-tris (m-methylbenzoate) europium (or terbium) complexes in SiO_2 gel 被引量:1
19
作者 WANGShuping WANGRuifen +1 位作者 ZHANGJianjun SHIShikao 《Rare Metals》 SCIE EI CAS CSCD 2002年第2期127-130,共4页
Silica gel luminophors containing 1, 10-phenanthroline-tris(M-Methylbenzoate) europium (or terbium) com- plexes were prepared bysol-gel method. The thermal decomposition, excitation and emissionspectra for the gel pho... Silica gel luminophors containing 1, 10-phenanthroline-tris(M-Methylbenzoate) europium (or terbium) com- plexes were prepared bysol-gel method. The thermal decomposition, excitation and emissionspectra for the gel phos- phors were measured and compared with thatof solid complex powders. The thermal stability of the complexes wasen- hanced in SiO_2 host matrix and the luminescence intensityremained unchanged. 展开更多
关键词 sol-gel thermal stability luminesscence europium (or terbium) complex
下载PDF
Radioactive Ages of Metal-Poor Halo Stars 被引量:1
20
作者 JiLi GangZhao 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2004年第1期75-87,共13页
The abundances of long-lived radioactive elements Th and U observed in metal-poor halo stars can be used as chronometers to determine the age of individual stars, and hence set a lower limit on the age of the Galaxy a... The abundances of long-lived radioactive elements Th and U observed in metal-poor halo stars can be used as chronometers to determine the age of individual stars, and hence set a lower limit on the age of the Galaxy and hence of the universe. This radioactive dating requires the zero-decay productions of Th and U, which involves complicated r-process nucleosynthesis calculations. Several parametric r-process models have been used to calculate the initial abundance ratios of Th/Eu and U/Th, but, due to the sharp sensitivity of these models to nuclear physics inputs, the calculations have relatively large uncertainties which lead to large uncertainties in the age determinations. In order to reduce these uncertainties, we present a simple method to estimate the initial productions of Th and U, which only depends on the solar system abundances and the stellar abundances of stable r-process elements. From our calculations of the initial abundance ratios of Th/Eu and U/Th, we re-estimate the ages of those very metal-poor halo stars with published abundances of Th and U. Our age estimates are consistent, within the errors, with the other age determinations derived from r-process models, and offer useful constrains for r-process theoretical calculations. The advantages and limitations of our simple method of radioactive dating are discussed. 展开更多
关键词 stars: abundances stars: population II galaxy: abundances galaxy: halo galaxy: evolution
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部