Evolution of zinc morphology during continuous electrodeposition

The morphology evolution of zinc continuous electrodeposits with nano-sized crystals on the ferrite substrate has been studied by in-situ scanning tunnel spectroscopy (STM). It is found that the morphology of zinc electrodeposits varies from initial granules with a size of about 30nm to layered platelets with increasing deposition time. Meanwhile, the crystal structure of the zinc electrodeposits is identified to be hexagonal η-phase by X-ray diffraction. The orientation relationship between zinc crystals and the substrate surface can be interpreted in terms of the misfit and the atomic correspondence of the interphase boundary between the η-phase deposits and α-Fe substrate.     

Topography,structure, and formation kinetic mechanism of carbon deposited onto nickel in the temperature range from 400 to 850℃

The carbon deposition behavior on nickel particles was observed within the temperature range from 400 to 800℃ in a pure methane atmosphere. The topography, properties, and molecular structure of the deposited carbon were investigated using field-emission scanning electron microscopy (FESEM), temperature-programmed oxidation (TPO) technology, X-ray diffraction (XRD), and Raman spectroscopy. The deposited carbon is present in the form of a film at 400-450℃, as fibers at 500-600℃, and as particles at 650-800℃. In addition, the structure of the deposited carbon becomes more ordered at higher temperatures because both the TPO peak temperature of deposited carbon and the Raman shift of the G band increase with the increase in experimental temperature, whereas the intensity ratio between the D bands and the G band decreases. An interesting observation is that the carbon deposition rate is suppressed in the medium-temperature range (M-T range) and the corresponding kinetic mechanism changes. Correspondingly, the FWHM of the G and D1 bands in the Raman spectrum reaches a maximum and the intensities of the D2, D3, and D4 bands decrease to low limits in the M-T range. These results indicate that carbon structure parameters exhibit two different tendencies with respect to varying temperature. Both of the two group parameters change dramatically as a peak function with increasing reaction temperature within the M-T range.     

One-pot synthesis and optical properties of In-and Sn-doped ZnO nanoparticles

Colloidal indium-doped zinc oxide (IZO) and tin-doped zinc oxide (ZTO) nanoparticles were successfully prepared in organic solution,with metal acetylacetonate as the precursor and oleylamine as the solvent.The crystal and optical properties were characterized by X-ray diffraction,UV-visible spectrophotometry,and fluorescence spectroscopy,respectively;the surface and structure morphologies were observed by scanning electron microscopy and transmission electron microscopy.The XRD patterns of the IZO and ZTO nanoparticles all exhibited similar diffraction peaks consistent with the standard XRD pattern of ZnO,although the diffraction peaks of the IZO and ZTO nanoparticles were slightly shifted with increasing dopant concentration.With increasing dopant concentration,the fluorescent emission peaks of the IZO nanoparticles exhibited an obvious red shift because of the difference in atomic radii of indium and zinc,whereas those of the ZTO nanoparticles exhibited almost no shift because of the similarity in atomic radii of tin and zinc.Furthermore,the sizes of the IZO and ZTO nanoparticles distributed in the ranges 20-40 and 20-25 nm,respectively,which is attributed to the difference in ionic radii of indium and tin.     

Circular dichroism spectral studies on the recombinant human neuroglobin

Neuroglobin (NGB) is a newly discov- ered member of the hemoglobin superfamily that is primarily expressed in the brain of humans and other vertebrates. The effects of protein concentration, solvent, pH and temperature on the secondary structure of NGB were investigated by employing far UV circular dichroism (CD) spectroscopy. The results show that NGB exists mainly in α-helix form when its concentration is less than 10 μmol/L. However, its α-helix content decreases with the increase of con- centration in the range of 10―40 μmol/L and remains unchanged when the concentration is higher than 40 μmol/L, which suggest that NGBs form intermolecular disulfide bond and aggregate in higher concentration. The α-helix content of NGB in methanol and ethanol is a little higher than that in water, indicating a higher stability of NGB in these solvents. NGB loses its α-helical secondary structure in either acidic or alka- line solution to some extent. Although increased temperature destabilizes the α-helices of NGB, over 16% of α-helices can be kept at 110°C. Therefore, NGB is a protein with hyperthermal stability.     

Topography,structure,and formation kinetic mechanism of carbon deposited onto nickel in the temperature range from 400 to 850°C

The carbon deposition behavior on nickel particles was observed within the temperature range from 400 to 800°C in a pure methane atmosphere.The topography,properties,and molecular structure of the deposited carbon were investigated using field-emission scanning electron microscopy(FESEM),temperature-programmed oxidation(TPO) technology,X-ray diffraction(XRD),and Raman spectroscopy.The deposited carbon is present in the form of a film at 400–450°C,as fibers at 500–600°C,and as particles at 650–800°C.In addition,the structure of the deposited carbon becomes more ordered at higher temperatures because both the TPO peak temperature of deposited carbon and the Raman shift of the G band increase with the increase in experimental temperature,whereas the intensity ratio between the D bands and the G band decreases.An interesting observation is that the carbon deposition rate is suppressed in the medium-temperature range(M-T range) and the corresponding kinetic mechanism changes.Correspondingly,the FWHM of the G and D1 bands in the Raman spectrum reaches a maximum and the intensities of the D2,D3,and D4 bands decrease to low limits in the M-T range.These results indicate that carbon structure parameters exhibit two different tendencies with respect to varying temperature.Both of the two group parameters change dramatically as a peak function with increasing reaction temperature within the M-T range.     

One-pot synthesis and optical properties of In-and Sn-doped ZnO nanoparticles

Colloidal indium-doped zinc oxide(IZO) and tin-doped zinc oxide(ZTO) nanoparticles were successfully prepared in organic solution,with metal acetylacetonate as the precursor and oleylamine as the solvent. The crystal and optical properties were characterized by X-ray diffraction,UV?visible spectrophotometry,and fluorescence spectroscopy,respectively; the surface and structure morphologies were observed by scanning electron microscopy and transmission electron microscopy. The XRD patterns of the IZO and ZTO nanoparticles all exhibited similar diffraction peaks consistent with the standard XRD pattern of Zn O,although the diffraction peaks of the IZO and ZTO nanoparticles were slightly shifted with increasing dopant concentration. With increasing dopant concentration,the fluorescent emission peaks of the IZO nanoparticles exhibited an obvious red shift because of the difference in atomic radii of indium and zinc,whereas those of the ZTO nanoparticles exhibited almost no shift because of the similarity in atomic radii of tin and zinc. Furthermore,the sizes of the IZO and ZTO nanoparticles distributed in the ranges 20–40 and 20–25 nm,respectively,which is attributed to the difference in ionic radii of indium and tin.     

Mechanical behavior study of microdevice and nanomaterials by Raman spectroscopy: a review

With the rapid development of micro/nano manufacturing technology and nanomaterials, the accurate measurement of the mechanical properties and behaviors at the micronano scale represents a new field of mechanical experiments. Raman spectroscopy, which is based on lat tice dynamics theory, is applicable to the detection of the statistical information of the lattice structure deformation within the measuring points. Due to its peculiarities, such as non-destructiveness, convenience and highresolution, this technology allows the online in situ measurement of residual stress in microstructures caused by processing and can also achieve the realtime deformation of graphene, carbon nanotubes and other nanomaterials under force loading. In recent years, mechanical measurements based on Raman spectroscopy technology have developed rapidly. In this review, Ramanbased stress measurement theories for several commonly used materials are briefly described. Applications related to the residual stress measurements of microstructure and experimental investigations of the mechanical properties of lowdimensional nanomaterials are then reviewed. Finally, the development trend of this method is proposed.     

Progress in measuring biophysical properties of membrane proteins with AFM single-molecule force spectroscopy

Membrane proteins are crucial in cell physiological activities and are the targets for most drugs.Thus,investigating the behaviors of membrane proteins not only provide deeper insights into cell function,but also help disease treatment and drug development.Atomic force microscopy is a unique tool for investigating the structure of membrane proteins.It can both image the morphology of single native membrane proteins with high resolution and,via single-molecule force spectroscopy(SMFS),directly measure their biophysical properties during molecular physiological activities such as ligand binding and protein unfolding.In the context of molecular biomechanics,SMFS has been successfully used to understand the structure and function of membrane proteins,complementing the static three-dimensional structures of proteins obtained by X-ray crystallography.Here,based on the authors’antigen-antibody binding force measurements in clinical tumor cells,the principle and method of SMFS is discussed,the progress in using SMFS to characterize membrane proteins is summarized,and challenges for SMFS are presented.     

A New Hidden Markov Model for Protein Quality Assessment Using Compatibility Between Protein Sequence and Structure

Protein structure Quality Assessment（QA） is an essential component in protein structure prediction and analysis. The relationship between protein sequence and structure often serves as a basis for protein structure QA.In this work, we developed a new Hidden Markov Model（HMM） to assess the compatibility of protein sequence and structure for capturing their complex relationship. More specifically, the emission of the HMM consists of protein local structures in angular space, secondary structures, and sequence profiles. This model has two capabilities：（1） encoding local structure of each position by jointly considering sequence and structure information, and（2）assigning a global score to estimate the overall quality of a predicted structure, as well as local scores to assess the quality of specific regions of a structure, which provides useful guidance for targeted structure refinement. We compared the HMM model to state-of-art single structure quality assessment methods OPUSCA, DFIRE, GOAP,and RW in protein structure selection. Computational results showed our new score HMM.Z can achieve better overall selection performance on the benchmark datasets.     

锌指蛋白ZNF191(243-368)G321A;N324L;G321A/N324L突变体的制备和表征

通过分子生物学的蛋白质工程方法对锌指蛋白ZNF191(243—368)的第三锌指区(Gly321和Asn324进行了定点突变，在大肠杆菌BL21中表达，通过DEAE52，CM23，肝素柱CL-6B纯化，最终获得了ZNF191(243—368)(G321A；N324L；G321A／N324L等3个突变体蛋白，运用凝胶电泳、UV光谱、EDTA滴定、金属离子(Co^2’，Ni^2 )取代等方法对突变体蛋白进行了初步表征，这为今后进一步研究该蛋白的结构和功能提供了必要的物质基础。     

人类锌指蛋白新基因ZNF641的克隆及表达

从人类心脏cDNA文库中分离并鉴定了一个新的人类锌指基因ZNF641,该基因的cDNA序列全长4．9kb,编码一个含438个氨基酸的蛋白质,从进化上看,该蛋白质在从小鼠到人的脊椎动物中都高度保守．Northern Blot分析显示：ZNF641在人类的多数组织中都有表达,尤其是在骨骼肌中有较高水平的表达．而亚细胞定位则显示ZNF641在细胞核及细胞质中均有定位．     

一个新C2H2型锌指蛋白的功能的初步研究

通过筛选人18周胎脑cDNA文库,得到一条编码332AA的全长新基因,生物信息学研究表明,该蛋白质序列有2个C2H2型锌指结构,其中1个锌指结构有RNA－binding蛋白特异锌指的特征,虽然同源比较发现与多种蛋白质精氨酸N端转甲基酶（protein arginine N-methyltransferase) 有一定的同源性,但新锌指蛋白不含转甲基酶的活性功能区域,属功能未知的基因,利用芯片研究功能未知基因的表达是一种较好的手段,通过代谢增强剂PMA（phorbol myristae acetate)刺激培养的血管内皮细胞,观察细胞受激活后新锌指蛋白基因的表达变化,结果表明新基因表达量提高了11倍以上,证实新基因属内皮细胞的极早期应答基因（Immediate early response gene,ERG)。     

健康家兔晶状体激光拉曼光谱研究

激光拉曼光谱法被公认为是研究生物大分子的结构、动力学和功能的有效方法。对健康家兔晶状体的激光拉曼光谱进行研究,发现在710 cm-1到1 280 cm-1区域内,健康家兔晶状体表现为典型的蛋白质拉曼光谱区,说明健康家兔晶状体主要由α、β和γ-蛋白组成的,以β折叠结构为主。对家兔晶状体蛋白侧链中酪氨酸残基的微环境研究表明,晶状体中酪氨酸残基大部分处于"暴露"状态,而有一小部分处于"埋藏"状态。     

水稻C2H2型锌指蛋白OsZAT12转化拟南芥功能的初步研究

摘要:植物C2H2型锌指蛋白是植物转录调节因子中的大家族,通过转录调控、翻译后调节和蛋白质间的相互作用在植物发育和环境胁迫中发挥关键作用. 本研究在水稻基因组中克隆到一个C2H2型锌指蛋白,命名为OsZAT12. 生物信息学分析显示OsZAT12全长597bp,其中不包含内含子,其蛋白质序列含有199个氨基酸,具有两个典型的C2H2锌指结构. OsZAT12蛋白定位于细胞核,在根中特异性表达.过表达拟南芥植株与野生型比较,其根变短,子叶的变绿率明显降低,植株矮小.初步推断OsZAT12可能影响植物生长发育尤其是根的伸长.     

同源模建法建立和检验人类新基因ZNF191锌指基序的三维构象

以实验室自行克隆的新基因ＺＮＦ１９１顺序为材料，按三联体密友转换出锌指基因编码的４个锌指结构域ＮＦ１９１ａ，ｂ，ｃ和ｄ的蛋白质一级顺序，并将它们与已用晶体衍射法确证了空间构象的７个Ｃｙｓ２Ｈｉｓ２（Ｃ２Ｈ２）型锌指进行同源比较，从中发现锌指７ＺＮＦ和１ＺＮＦ的一级结构与待检验的锌指顺序同源高且间隙较小。