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71.
Chemical synthesis in combination with precision polymer modification allows the systematic exploration of the effect of protein properties, such as charge and hydrodynamic radius, on potency using defined, homogeneous conjugates. A series of polymer-modified synthetic erythropoiesis proteins were constructed that had a polypeptide chain similar to the amino acid sequence of human erythropoietin but differed significantly in the number and type of attached polymers. The analogs differed in charge from +5 to -26 at neutral pH and varied in molecular weight from 30 to 54 kDa. All were active in an in vitro cell proliferation assay. However, in vivo potency was found to be strongly dependent on overall charge and size. The trends observed in this study may serve as starting points for the construction of more potent synthetic EPO analogs in the future.  相似文献   
72.
A newly developed unbiased structural optimization method, named dynamic lattice searching (DLS), is proposed as an approach for conformational analysis of atomic/molecular clusters and used in understanding the energy landscape of large clusters. The structures of clusters are described in terms of the number of basic tetrahedron (BT) units they contain. We found that the hit numbers of different structural motifs in DLS runs is proportional to the number of BTs. A parameter T(max) is defined to limit the maximal number of atoms moved in a structural transition. Results show that T(max) is a key parameter for modulating the efficiency of the DLS method and has a great influence on the hit number of different motifs in DLS runs. Finally, the effect of potential range on the conformational distribution of the (Morse)(98) cluster is also discussed with different potential-range parameters.  相似文献   
73.
人血清与头发中铜,锌,铁,钙,镁,锰含量的相关分析   总被引:3,自引:0,他引:3  
平行测定了54例(男31例,女23例)成人血清和头发中铜,锌,铁,钙,镁和锰的含量,相关分析结果表明,血清与头发中6种元素的不相关两类样品比较,血清测定方法简便,误差小,但在检测人体内元素含量水平时,头发的测量结果比血清更灵敏。  相似文献   
74.
CO2部分氧化乙烷制乙烯Pd—Cu/MoO3—SiO2催化剂的研究   总被引:7,自引:0,他引:7  
李青  钟顺和 《应用化学》1998,15(6):49-52
用化学吸附-红外光谱、化学吸附-程序升温脱附(TPD)和微型反应技术研究了Pd-Cu/MoO3-SiO2(MoSO)催化剂对CO2和乙烷的吸附活化和部分氧化反应性能.结果表明,乙烷以C—H键中的H吸附于MoSO载体表面MoO键的端基氧上;Pd-Cu/MoSO催化剂对CO2有良好的化学吸附活化性能,CO2的吸附除有线式吸附态和剪式吸附态外,还有一种新的卧式吸附态;Pd-Cu/MoSO催化剂的晶格氧参与了化学反应.探讨了在Pd-Cu/MoSO催化剂上CO2的部分氧化乙烷反应机理  相似文献   
75.
A new isoprenyl phenyl ether, 3-hydroxy-4-(3-methylbut-2-enyloxy)benzoic acid methyl ester (1), together with 4-hydroxybenzoic acid (2), 2-hydroxy-6-methylbenzoic acid (3), and 4-hydroxy-3-methoxybenzoic acid (4) were isolated from Mangrove fungus (No. B60) from the South China Sea. The structures of the compounds were established on the basis of NMR spectroscopic and mass spectrometric data. In the preliminary bioassay, compound 1 exhibited antibacterial and antifungal activities. Compound 1 also inhibited cytotoxicity to the hepG2 cell line with an IC50 value of 10.0 μg/mL. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 313–314, July–August, 2007.  相似文献   
76.
煤中15种微量元素在燃烧产物中的分配   总被引:21,自引:1,他引:21  
建立了燃煤中15种向量元素在悄灰和底灰中含量分布的经验公式,该公式可以估算煤中微量元素在燃烧产物中的分配及传输通量。煤中非挥发性元素大部分存在于底灰和飞灰中,挥发性元素进入大气的量较高。  相似文献   
77.
  Electrospraying/electrospinning of poly(γ-stearyl-L-glutamate) (PSLG) was investigated on a series solutions with different concentrations in chloroform. Field emission scanning electron microscopy (FESEM) and attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR) were used to characterize the morphology and structure of the electrosprayed/electrospun polypeptide mats. It was found that electrospraying of PSLG with concentrations lower than 16 wt% afforded beads, while microfibers could be electrospun at the concentration of 22 wt%. The hydrophobicity of the electrosprayed/electrospun PSLG mats was investigated with static water contact angle (WCA) and tilt angle measurements. It was demonstrated that the superhydrophobic surfaces of PSLG with WCAs and tilt angles in the ranges of 150°-170° and 16.5°-4.2°, respectively, were obtained through electrospraying/electrospinning process.  相似文献   
78.
The structure and properties of the blend of regenerated silk fibroin (RSF) and poly(vinyl alcohol) (PVA) were investigated. The two polymers in the blend are in the state of phase segregation. Infrared (IR) spectra indicate that the RSF in the blend maintains its intrinsic properties, thus, ethanol treatment can transfer silk I structure of RSF to silk II structure. The water absorption property and mechanical property of the blend are improved in comparison with those of RSF. The blend maintains the major merit of RSF, that is, it can immobilize glucose oxidase on the basis of the conformational transition from silk I structure to silk II structure. The properties of the immobilized enzyme are examined. Moreover, the second generation of glucose sensor based on the immobilized enzyme is fabricated and it has a variety of advantages including easy maintenance of enzyme, simplicity of construction, fast response time and high stability.  相似文献   
79.
烟酸对酸性硫酸盐体系铜电沉积的影响   总被引:2,自引:0,他引:2  
对溶液A: 0.8 mol•L-1硫酸铜,0.6 mol•L-1硫酸,5.0×10-5 mol•L-1氯离子,1.0×10-4 mol•L-1聚乙二醇的溶液,溶液B:在溶液A中加入2.0×10-2 mol•L-1烟酸,pH为0.5,运用循环伏安和计时安培法研究玻碳电极上铜的电沉积行为.结果表明,铜的电沉积过程经历了晶核形成过程,其电结晶按瞬时成核和三维生长方式进行.烟酸的加入对铜的电沉积具有阻化作用,但不改变铜的电结晶机理.沉积层的X射线衍射表明Cu为面心立方结构,在烟酸存在下沉积层出现(220)高择优取向,这可能是烟酸在Cu(220)晶面上发生强烈吸附作用的结果.  相似文献   
80.
将叔丁基引入到酰基 (硫 )脲骨架中 ,设计合成了 8个未见文献报道的N′ 叔丁基 N 取代酰基脲及N′ 叔丁氨基羰基 N 取代酰基硫脲类化合物 ,其结构经元素分析、IR和1 HNMR得到确证 .初步的生物活性测试结果表明部分化合物具有较好的除草活性  相似文献   
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