Structure-activity relationship of CAP-1, a cuticle peptide of the crayfish Procambarus clarkii, in terms of calcification inhibitory activity

CAP-1 is a cuticle peptide isolated from the acid-insoluble fraction of the exoskeleton of the crayfish Procambarus clarkii. CAP-1 is an acidic peptide and comprises 78 amino acid residues. The C-terminal part is especially highly acidic by a phosphoserine and an Asprepeat, which is thought to be responsible for the calcification inhibitory activity in vitro. To examine the significance of the Asp-repeat and to get information on structure-activity relationship, various small related peptides with different sequences were synthesized and tested for the inhibitory activity. The results showed that 1) the activity depends not on the Asp-containing sequence but on the total number of Asp residues, 2) peptide conformation does not affect the activity, and 3) Asp is more effective in inhibitory activity than Glu. These characteristics seem to be consistent with the fact that acidic matrix proteins identified so far from various biominerals have almost no sequence similarity, leading to the idea that the molecular evolution of matrix proteins and peptides in biominerals might be intrinsically different from that of enzymes, hormones and other important functional proteins possibly due to the difference in the mode of interaction between proteins and inorganic compounds, or between proteins and organic compounds.     

西洋参中人参皂苷Rg1、Re、Rb1基体标准物质的研制

建立高效液相色谱法和高效毛细管电泳法,对研制的西洋参基体标准物质中人参皂苷Rg₁、Re、Rb₁含量进行准确定值,同时考察了样品的均匀性、稳定性和样品的最小取样量,最后对标准物质的不确定度进行了评定。评定结果为人参皂苷Rg₁、Re、Rb₁含量分别为（1.72±0.14）mg/g、（15.3±1.5）mg/g、（25.8±2.8）mg/g,相对扩展不确定度分别为8.4％、10％、11％,可为西洋参的质量控制提供依据。     

Enhanced photoelectrochemical activity of the TiO2 /ITO nanocomposites grown onto single-walled carbon nanotubes at a low temperature by nanocluster deposition

High-resolution transmission electron microscopy (HRTEM) is used to observe a TiO2/ITO-coated composite nanostructure grown onto single-walled carbon nanotubes (SWCNTs). The SWCNTs, indium tin oxide (ITO), and TiO2 mixtures of anatase (A) and rutile (R) are clearly distinguished in the HRTEM images. The thickness of the SWCNT was about 3 nm, and the TiO2 shell included different polycrystalline structures.     

Machine scheduling in the presence of sequence-dependent setup times and a rate-modifying activity

Rate modifying activity (RM) is a type of maintenance after which the processing rate of the machine increases. RM is a very new topic in academic studies. However, it is very common in real world situations. In this paper, we study the integrated problem of assigning a common due-date to all jobs, scheduling the jobs and making decisions about the position of RM in a single machine environment in which the setup times are sequence dependent. The objective is minimising the summation of earliness costs, tardiness costs and due date related costs. This problem has never been studied in the literature with any arbitrary criterion. We construct a time-dependent travelling salesman problem (TDTSP) formulation for this problem. The position of the optimal common due date and some dominance properties for the position of RM are presented. A branch and bound (B&B) procedure is developed to solve the problem optimally. Numerical results justify the effectiveness of the B&B method for small problems. For larger problems, two robust metaheuristics are proposed.     

Synthesis of an extremely stable ceramic in the system Si/B/C/N using 1-(trichlorosilyl)-1-(dichloroboryl)ethane as a single-source precursor

 A new material discovered in the Si/B/C/N system was found to remain in the amorphous state up to a very high temperature of 2000°C. This material, with the composition Si₂B₂N₅C₄, is the only material in this system which does not undergo any microstructural changes until such high temperatures. Furthermore, the substance shows an extremely high resistance to oxidation up to 1500°C. The synthesis of amorphous Si₂B₂N₅C₄ was achieved by using the novel single-source precursor 1-(trichlorosilyl)-1-(dichloroboryl)ethane (TSDE), which can be synthesized in high yields from inexpensive starting materials in a simple single pot reaction. Examination of the structural properties of the pyrolytic ceramic reveals a substructure consisting of tetrahedrally and trigonally-planar coordinated silicon and boron, respectively. Si-C- and B-C-bonds present in the molecular precursor could not be distinguished from Si-N- and B-N-bonds in the fully pyrolized ceramic. EDX and X-ray-diffraction showed the material to have a homogeneous elemental distribution, and no phase separation could be detected. Received: 15 August 1998 / Reviewed and accepted: 24 September 1998     

渤海辽东带地质认识的突破与金县1-1大油田的发现

辽东带系指渤海辽中凹陷的东部陡坡带及辽东凸起,被辽中及辽东凹陷所夹持。辽东带油源条件好,东营组储—盖条件优越,断鼻、断块圈闭发育。但在2002年之前的15年内,国内外公司在辽东带进行了长期研究和勘探,钻了12口探井,没有发现商业油气田。经过对辽东带油气地质条件3年的深入研究,对每口失利井原因进行了再次分析,认识到该带发育东营组及沙河街组两套主力成藏组合,控制东营组成藏的主要因素是油气运移,而沙河街组能否成藏关键是储层。在此认识指导下选择研究方向,评价有利目标,经钻探发现了金县1-1大油田,储量达1.5×108 m3,充分显示了科研在油气勘探中的作用。     

Photocatalytic activity of pulsed laser deposited TiO2 thin films in N2, O2 and CH4

We report on pulsed laser deposition of TiO₂ films on glass substrates in oxygen, methane, nitrogen and mixture of oxygen and nitrogen atmosphere. The nitrogen incorporation into TiO₂ lattice was successfully achieved, as demonstrated by optical absorption and XPS measurements. The absorption edge of the N-doped TiO₂ films was red-shifted up to ∼ 480 nm from 360 nm in case of undoped ones.The photocatalytic activity of TiO₂ films was investigated during toxic Cr(VI) ions photoreduction to Cr(III) state in aqueous media under irradiation with visible and UV light. Under visible light irradiation, TiO₂ films deposited in nitrogen atmosphere showed the highest photocatalytic activity, whereas by UV light exposure the best results were obtained for the TiO₂ structures deposited in pure methane and oxygen atmosphere.     

Al-Mg-Sc-Ti合金中Al3(Scx,Ti1-x)粒子的析出行为

用激冷铸造法制备Al-5.5Mg-0.25Sc-0.04Ti合金,研究了在不同温度退火后其硬度随时间的变化,并用金相显微镜(OM)和透射电镜(TEM)研究了这种合金中Al₃(Sc_x,Ti_1-x)第二相粒子的存在形式和形成机制。结果表明：用急冷铸造法制备的Al-5.5Mg-0.25Sc-0.04Ti铸态合金中Sc和Ti原子主要以固溶的形式存在于α(Al)基体中,在电镜下很难观察到这些粒子。铸态合金在较低温度(低于250℃)下退火时其硬度提高得比较慢,退火较长时间才能出现硬度的峰值;而在比较高的温度(高于350℃)退火硬度提高得非常快,很快出现峰值。但是,硬度出现峰值后继续退火则大幅度降低;在300℃退火硬度的热稳定性比较高。硬度的变化,与次生Al₃(Sc_x,Ti_1-x)粒子的析出密切相关。在较低温度下次生Al₃(Sc_x,Ti_1-x)粒子的析出不充分且粒径较小,对晶界、亚晶界和位错的钉扎作用较弱;而在过高的温度下Al₃(Sc_x,Ti_1-x)粒子发生粗化,使合金的性能降低。     

GexSi1-x/Si中应变的会聚束电子衍射研究

介绍了会聚束电子衍射（ＣＢＥＤ）技术与计算机模拟相结合测定ＧｅｘＳｉ１－ｘ／Ｓｉ化学梯度层中应变分布的实验结果,提供了一种高空间分辨率,高灵敏度,且适用于任何材料系中微区晶格常数测定及应变分布研究的技术途径。     

La2/3Sr1/3MnO3掺杂RE(RE=Pr、Eu、Y、Tb)的结构、红外及磁学性质

采用空气中固相反应烧结法制备了一系列钙钛矿结构的(La1-xREx)2/3Sr1/3MnO3(RE=Pr、Eu、Y、Tb;x=0、0.3或0.4)掺杂稀土锰氧化物多晶样品.X射线衍射(XRD)分析表明随着RE离子半径的减小,样品XRD的衍射峰位置普遍向高角度偏移,2θ增大0.02～0.62°.扫描电镜(SEM)观测的结果表明掺杂RE离子的半径越小,形成多晶样品的晶粒越小,未掺杂RE的La2/3Sr1/3MnO3在所有的样品中晶粒最大.红外吸收光谱测量发现样品在599～629cm-1范围出现了吸收峰并且峰的位置随掺杂RE离子半径的减小而向低频方向偏移.样品的磁性质测量表明掺杂稀土离子的半径及磁矩对材料的磁电阻有明显影响.     

Pressure difference across the free surface of a stable static meniscus in a possible Ge1−XSiX ribbon growth by edge-defined film-fed growth (E.F.G.) technique

In this paper, it is shown in which kind the pressure difference across the free surface has to be chosen to obtain a stable convex static meniscus with a prescribed size in the case of a Ge_1−XSi_X single crystal ribbon growth by E.F.G. technique. The dependence of the pressure difference on the composition X is analyzed. The same tools as for a Ge or Si single crystal ribbon growth are used. The results can be useful in a future experiment planning or manufacturing technology design.     

Systematic study of the complex structure of N1 Deep Level Transient Spectroscopy signal in Cu(In,Ga)Se2 based heterojunctions

The goal of this work is to classify and systematically investigate the N₁ Deep Level Transient Spectroscopy (DLTS) response characteristic for Cu(In,Ga)Se₂-based heterojunctions. Up to four different peaks giving rise to the N₁ signal are observed. It is shown that the contribution of the components strongly depends on the metastable state of the sample (different kind of light soaking and reverse bias treatment) and measurement conditions. In the second part of the paper the unusual features of the N₁ response, such as an enormously high signal level, are discussed. It is argued, basing on the correlations between capacitance-voltage curves and DLTS spectra, that some of the properties might be due to intrinsic In_Cu DX centers.     

Doping-induced microstructural, textural and optical properties of In2Ti1−xVxO5+δ semiconductors and their role in the photocatalytic splitting of water

The physicochemical properties of V-doped indium titanates (In₂Ti_1−xV_xO_5+δ, 0.0 ≤ x ≤ 0.2) were investigated by using XPS, powder XRD, UV–vis, SEM and luminescence spectroscopy techniques. The Rietveld refinement of XRD data revealed that even though the V-containing samples were isostructural with In₂TiO₅ (orthorhombic space group Pnma), a systematic x-dependent variation was noticeable in the Ti–O bond lengths in [TiO₆] octahedral units, cell parameters and in the value of δ. XPS results confirmed the coexistence of V⁵⁺ and V⁴⁺ states, leading thereby to an enhancement in oxygen non-stoichiometry in the doped samples. A loading-dependent progressive shift from 400 to 750 nm was also observed in the onset of the absorption edge, indicating a significant narrowing of the band gap. Furthermore, the samples with higher V-content were comprised of the grain clusters having larger size and an irregular shape. The UV–vis, photoluminescence and thermoluminescence studies indicate that the doping-induced lattice defects may give rise to certain closely spaced acceptor/donor energy levels in between the band gap of host matrix. The indium titanates are found to serve as stable photocatalysts for water splitting under visible light, where oxygen was the major reaction product. The role of microstructural and morphological properties in the photocatalytic activity is discussed.     

The Biofunctions of Phytochemicals and Their Applications in Farm Animals: The Nrf2/Keap1 System as a Target

Reactive oxygen species (ROS) can be caused by mechanical, thermal, infectious, and chemical stimuli, and their negative effects on the health of humans and other animals are of considerable concern. The nuclear factor (erythroid-derived 2)-like 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) system plays a major role in maintaining the balance between the production and elimination of ROS via the regulation of a series of detoxifying and antioxidant enzyme gene expressions by means of the antioxidant response element (ARE). Dietary phytochemicals, which are generally found in vegetables, fruits, grains, and herbs, have been reported to have health benefits and to improve the growth performance and meat quality of farm animals through the regulation of Nrf2-mediated phase II enzymes in a variety of ways. However, the enormous quantity of somewhat chaotic data that is available on the effects of phytochemicals needs to be properly classified according to the functions or mechanisms of phytochemicals. In this review, we first introduce the antioxidant properties of phytochemicals and their relation to the Nrf2/Keap1 system. We then summarize the effects of phytochemicals on the growth performance, meat quality, and intestinal microbiota of farm animals via targeting the Nrf2/Keap1 system. These exhaustive data contribute to better illuminate the underlying biofunctional properties of phytochemicals in farm animals.     

CdS/CNT-TiO2光催化剂的合成及其对亚甲基蓝的光催化降解（英文）

采用多壁碳纳米管(MWCNTs)为载体,分别以醋酸镉((CH3COO)2Cd.2H2O)和硫化钠(Na2S.5H2O)为镉源和硫源,经简单逐滴滴入途径制备了CdS/CNT复合材料。再以四丁氧基钛(TNB)为钛源,苯为溶剂,成功地将二氧化钛(TiO2)纳米粒子沉积在CdS修饰的MWCNTs表面而得到CdS/CNT-TiO2光催化剂。利用N2吸附等温线、扫描电子显微镜、X射线衍射、能量分散性X射线分析以及透射电子显微镜对所制CdS/CNT-TiO2光催化剂进行表征。CdS/CNT-TiO2复合材料呈多孔结构,MWCNTs均匀分散在材料中,且未出现明显的TiO2和CdS纳米颗粒团聚体。该材料在紫外和可见光照射下对亚甲基蓝具有优异的降解活性。这不仅归因于TiO2对自由基的反应和MWCNTs吸附能力,且归因于引入窄带隙半导体CdS,使粒子在MWCNTs表面的电子转移速率得到提高。     

Simultaneous determination of Np, Pu and Am in HNO3 solution by combining extraction, liquid scintillation counting, and α spectrometry

α Spectrometry is one of the most important and sensitive techniques for the assay of α-emitting nuclides, but various complicated procedures are often required for preparation of uniform thin plate source. Liquid scintillation counting (LSC) with pulse shape analysis (PSA) combining extraction is much simpler, more rapid and accurate technique, but the extraction processes are often very long. By combining extraction, LSC with PSA, and α spectrometry, we proposed a new approach to determine ²³⁷Np, ^238–240Pu and ²⁴¹Am. The new approach includes an extraction process of three steps for blind samples or of only one step for those samples without tailing interference with α spectra. Moreover, no complicated procedure is required for α plate source preparation because even non-uniform plate source is feasible for the new approach. The approach has taken advantages of high counting efficiency (nearly 100%) of LSC for α-radiation, high energy resolution of α spectrometry and high recovery yield of actinides by trialkylphosphine oxide (TRPO) extraction. The approach with one step extraction can be expected to determine ²³⁷Np, ^238–240Pu, ²⁴¹Am and ²⁴⁴Cm simultaneously.     

Differential effect of arecoline on the endogenous dioxin-responsive cytochrome P450 1A1 and on a stably transfected dioxin-responsive element-driven reporter in human hepatoma cells

Dioxin-responsive element-mediated chemical activated luciferase expression (DRE-CALUX) is one of alternative bioassays for the determination of dioxin levels. We have previously established a DRE-CALUX cell line, Huh7-DRE-Luc, by using stable transfection of Huh-7 cells with a reporter plasmid (4xDRE-TATA-Luc) carrying a DRE-driven firefly luciferase gene. It was also shown that arecoline, a major areca nut alkaloid, inhibited the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced cytochrome P450 1A1 (CYP1A1) activation in Huh-7 cells. The TCDD-activated aryl hydrocarbon receptor (AhR) induces the DRE-CALUX activation and CYP1A1 gene expression via binding to DRE in promoter regions of these dioxin-responsive genes. In the present study, the effect of arecoline on the TCDD-induced activation of DRE-CALUX and CYP1A1 enzyme in Huh7-DRE-Luc and Huh-7 cells, respectively, was examined. It was found that arecoline inhibited TCDD-induced CYP1A1 activation and however enhanced TCDD-induced DRE-CALUX activation. This finding indicates the differential effect of arecoline on the endogenous dioxin-responsive CYP1A1 and on a stably transfected DRE-driven reporter in human hepatoma cells. The present study suggests that induction of DRE-CALUX alone does not necessarily parallel with endogenous CYP1A1 gene expression, and that the reporter assay may detect interactions that are not functional in endogenous gene.