Hafnia nanoparticles - a model system for graphene growth on a dielectric

We study graphene growth on hafnia (HfO2) nanoparticles by chemical vapour deposition using optical microscopy, high resolution transmission electron microscopy and Raman spectroscopy. We find that monoclinic HfO2 nanoparticles neither reduce to a metal nor form a carbide while nucleating nanometer domain-sized few layer graphene. Hence we regard this as an interesting non-metallic catalyst model system with the potential to explore graphene growth directly on a (high-k) dielectric. HfO2 nanoparticles coated with few layer graphene by atmospheric pressure CVD with methane and hydrogen at 950 °C. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Graphene growth on hafnia (HfO2) nanoparticles by chemical vapour deposition (CVD) is studied. It is found that monoclinic HfO2 nanoparticles neither reduce to a metal nor form a carbide while nucleating nanometer domain-sized few layer graphene. Hence the authors of this Letter regard this as an interesting non-metallic catalyst model system with the potential to explore graphene growth directly on a (high-k) dielectric. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparative study of three short-chain neurotoxins from the venom of Naja kaouthia (Yunnan, China)

Three short-chain neurotoxins named NT-I, NT-II, and NT-III were purified from the venom of Naja kaouthia, a snake distributed throughout the south of Yunnan province, China, by a series of chromatographic steps, including an FPLC Resource S column. Their molecular weights, determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS, were 6952.19 Da, 6854.92 Da, and 6828.80 Da, respectively. NT-I consisted of 62 amino acid residues, and the other two consisted of 61 amino acid residues, including 8 cysteines. After hydrolysis by endoproteinase Glu-C, their primary sequences were determined. A test of their activities demonstrated that they effectively inhibited muscle contractions induced by electric stimulation. Furthermore, the extent of inhibition caused by NT-II and NT-III was less than that of NT-I. The IC(50)s were 0.04 mug/ml, 0.20 mug/ml, and 0.23 mug/ml for NT-I, NT-II, and NT-III, respectively. Compared with NT-II and NT-III, the higher activity of NT-I may be a result of the amino acid residue substitution Ile36 to Arg36.

Demonstration of some selected aquaculture technologies under farming system research in Jessore and Santahar, Bangladesh

BFRI evolved some selected aquaculture technologies viz. polyculture of carps in perennial ponds, monoculture of short cycled fish species (BFRI super strain) in seasonal ponds and prawn seed production through backyard hatchery system have been demonstrated under Farming System Research (FSR) component in Jessore and Santahar regions. Both polyculture of carps and monoculture of short cycled fish species technologies were tested in farmer's ponds in Kaium Kula village near Jessore town. In polyculture trials, seven species comprising of silver carp (Hypophthalmichthys molirrix), catla (Catla catla), rohu (Labeo rohita), grass carp (Ctenopharyngodon idellus), common carp (Cyprinus carpio), mrigal (Cirrhinus cirrhosus) and silver barb (Barbonymus gonionotus) were stocked @ 9,500 (ratio 6:2:4:2:1:5:5); 10,750 (ratio 6:2:4:2:1:5:5) and 12,000 (ratio 6:2:4:2:1:5:4) fish/ha respectively in ponds of T1, T2 and T3 having three replications of each. The mean highest fish production was 3,148 kg/ha in T3, followed by 2,899 kg/ha in T1 and 2,875 kg/ha in T2. Production of T3 was significantly different (P<0.05) than both T1 and T2, while there was no significant differences (P>0.05) between the production of T1 and T2. In case of trial of short cycled fish species, two treatments were tested: T1 (comprising of BFRI super strain of Nile tilapia, silver carp, common carp and silver barb; ratio 3:5:1:1) and T2 (having only BFRI super strain of Nile tilapia). Stocking density in both the treatments were same (20,000 fish/ha). In this trial average production was higher in T1 (2,743 kg/ha) than that of T2 (2,369 kg/ha) but the production figure in these two treatments was not significantly different (P>0.05). Demonstration of backyard prawn hatchery technology was tested at Santahar region of Bogra district, North-west part of Bangladesh. This hatchery consisted of three main components i) bio-filter, ii) rearing tank unit (chari) and iii) air blower/air pump unit. Plastic drum of 200-250 l capacity and cemented chari of 200-250 l capacity were used as bio-filter and larval rearing containers respectively. A 0.5 hp air blower with 6 aquarium air pump were used to operate the aeration system in the hatchery. Diluted sea water (10-12 ppt) made from brine solution (200-250 ppt) collected from salt-bed was used in the backyard hatchery system of hatching of eggs and rearing of larvae. Rearing of first stage zoea-larvae was reared in three rearing tanks following the stocking densities of 40, 50 and 60/l of water respectively. Production of post-larvae were 20±0.82, 22±1.12 and 28±1.63/liter of water in treatments I, II and III respectively in 38, 40 and 39 days rearing period.

随机扩增多态DNA影响因素的研究

随机扩增多态 DNA(PAPD）分析受诸多因素的影响, 作者发现不同厂家制造的 PCR 扩增仪, 不同厂家出品的 TaqDNA 聚合酶和 PCR 缓冲液, PAPD 反应体系中的引物浓度, Mg~(2+)浓度, dNTP 浓度, BSA（牛血清白蛋白）和明胶, 以及模板 DNA的量等均可能对 PAPD 结果有不同程度的影响. 为了使 PAPD 结果在不同实验室间具有重复性和可比性, 提高 PAPD 数据的科学价值, 作者建议在 PAPD 分析过程和文章写作中应规范化. 方法部分, 除一般写明的引物浓度、TaqDNA 聚合酶单位数、dNTP 浓度、每一次 PCR 反应的循环条件和循环数等外, 还应注明 PCR 仪的制造厂家及型号、TaqDNA 聚合酶生产厂家 、PCR 缓冲液的成分、Mg~(2+)浓度, 模板 DNA 浓度等。

抚仙湖有机污染物化学背景值及人淋巴细胞体外致突变性评定

用 XAD－2树脂提取抚仙湖7个采样点的有机物质水样提取物, 用气相色谱/质谱 (GC/MS) 进行分析. 在每种水样品中发现有上百种有机污染物. 提取物用培养的人淋巴细胞系姐妹染色单体交换 (SCE) 试验作致突变潜力检查. 结果显示, 仅入湖口水样在高浓度组 (0.0625L/mL) 诱发 SCE 明显增加。

HIV-1慢性感染Jurkat细胞系的建立及其特性研究

目的　建立艾滋病病毒Ⅰ型( HIV21) 慢性感染J urkat 细胞系,研究其生物学特性。方法　参照文献方法改良,建立HIV21 ⅢB慢性感染J urkat 细胞系。其细胞系特性采用以下方法检测:光学显微镜观察细胞形态;流式细胞仪检测HIV21 ⅢB感染细胞的阳性率;噻唑蓝(MTT) 法检测抗病毒药物对慢性感染细胞的毒性作用;酶联免疫吸附试验( EL ISA) 检测药物对慢性感染细胞中病毒复制的影响;合胞体形成方法检测药物对HIV21 ⅢB慢性感染细胞与正常细胞融合的阻断作用。结果　成功建立了HIV21 慢性感染J urkat 细胞系(J urkat/ HIV21 ⅢB ) ,感染细胞阳性率> 90 %。检测影响病毒复制各周期的抗病毒药物对J urkat/ HIV21 ⅢB细胞的作用,发现J urkat/ HIV21 ⅢB细胞具有 HIV21 慢性感染细胞的生物学特征。结论　成功建立J urkat/ HIV21 ⅢB 细胞系,为抗HIV21 药物的研发和病毒感染机制研究提供了新的工具。

Zinc coupling potentiates anti-HIV-1 activity of baicalin

Baicalin (BA) has been shown with anti-HIV-1 activity. Zinc is a nutrient element. The anti-HIV-1 activity of zinc complex of baicalin (BA-Zn) in vitro was studied and compared with the anti-HIV-1 activities between BA and BA-Zn in the present study. Our results suggested that BA-Zn has lower cytotoxicity and higher anti-HIV-1 activity compared with those of BA in vitro. The CC(50)s of BA-Zn and BA were 221.52 and 101.73 muM, respectively. The cytotoxicity of BA-Zn was about 1.2-fold lower than that of BA. The BA and BA-Zn inhibited HIV-1 induced syncytium formation, HIV-1 p24 antigen and HIV-1 RT production. The EC(50)s of BA-Zn on inhibiting HIV-1 induced syncytium formation (29.08 muM) and RT production (31.17 muM) were lower than those of BA (43.27 and 47.34 muM, respectively). BA-Zn was more effective than BA in inhibiting the activities of recombinant RT and HIV-1 entry into host cells. Zinc coupling enhanced the anti-HTV-1 activity of baicalin. (C) 2004 Elsevier Inc. All rights reserved.

Chemical Constituents from the Leaves and Stems of Schisandra rubriflora

Six new nortriterpenoids, schirubridilactones A-F (1-6). as well as 14 known compounds, were isolated from the leaves and stems of Schisandra rubriflora. The Structures of 1-6 were elucidated oil the basis of spectroscopic methods including HSQC, HMBC, H-1-H-1 COSY, and ROESY NMR experiments. The relative stereochemistry of I was confirmed through single-crystal X-ray analysis. In addition, compounds 1-6 showed anti-HIV-1 activity with EC50 values in the range 14.3-80.8 mu g/mL and Selectivity indices in the range 2.2-9.0.

Investigation on water quality in the Ashulia beel, Dhaka

The study was conducted to get an idea about the water quality of the Ashulia beel, and its temporal change over wet and dry seasons due to change of the physicochemical parameters. The water body has become a dumping ground of all kinds of solid, liquid and chemical wastes of bank side population and industries. Encroachment and illegal dredging has become a serious threat for the sound environment of the beel. The water parameters of pH 7.1-7.8 and alkalinity 30-63 mg/l in wet, and pH 7.1-8.4 and alkalinity 90-115 mg/l in dry season, respectively, which were within the standard range of DoE investigation. During wet season, EC 130-310 mg/l, TDS 80-132 mg/l, DO 1.1-2.1 mg/l and BOD -4.4-1.6 mg/l were measured. In dry season, EC 341-442 mg/l, TDS 207-276 mg/l, DO 0.5-2.0 mg/l and BOD 1.0-3.0 mg/l were measured. The comparative analysis showed that most of the water quality parameters of the Ashulia beel were suitable for aquatic organisms including fishes while the DO contents were much lower than the desirable level which may not be suitable for fishes.

Ecological impact of Mahshahr petrochemical activities on abundance and diversity of macrobenthic fauna in Zangi Creek (Persian Gulf)

The Moosa Creek extends from its opening into the Persian Gulf, with some sub narrow creeks leading to it. Zangi creek is one of the main branches of Moosa creek. The creek contains numerous sources of organic pollution, including sewage outlet flows and boat waste. After establishing the Petrochemical special Economic Zone (PETZONE) in 1997 near to the Zangi Creek, the pipelines, streets and railway made it distinct from eastern and western parts of this creek. Industrial activities have released sludge and effluents in this creek along these years. A survey of the Zangi creek was performed, assessing water properties, organic pollution, and the population density, distribution and diversity of macrobenthic fauna through bi-monthly sampling from July 2006 to September 2007. Samples were collected from water near the bottom and sediment at 7 stations include 2 stations inside the distinct Zangi creek and 4 stations along a transect with 1 km distances between them in eastern free part and one reference station located at the Persian Gulf entrance to the Moosa creek. The environmental parameters such as temperature, salinity, pH, dissolved oxygen, COD, turbidity, EC and heavy metals include Hg, Cd, Pb, Ni as well as percentage silt-clay and total organic matter of the sediment were measured. The faunal population density and their distribution are discussed in relation to the environmental changes. Results showed spatial heterogeneity in faunal distribution of the Zangi creek. Nine groups of macrofauna were identified out of distinct zangi creek. Polychaets formed the dominant group (48%) followed by bivalves (13%), gastropods (10%), Decapods (2%), Tanaids (5%), and all other groups (22%). The distinct creek was heavily polluted without any macrofauna communities probably as a consequence of the high pH, COD, low salinity and heavy metals contamination specially Cd and Pb. The other stations near to the disposal site were found with macrofauna communities commonly tolerant to organic pollution, At 3 km east of the disposal site, macrofauna is comparable to the surrounded creek, whereas macrofauna still indicate environmental degradation. Farther a way, faunal density decreases and equilibrium taxa gradually replace opportunistic species, while the other stations were far from polluted area contained lower pollution and relatively healthy macrofauna. The mean biomass of macrobenthic fauna were estimated for the whole studied area. The results are considered in Minimum density and biomass in surrounded creek and maximum density and biomass in 3 km of surrounded area. Biodiversity Indices were low in surrounded creek. The Shanon-weaver information index was used to describe the spatially variations in diversity. Macrofauna density, shanon and simpson index were significantly variable between surrounded and free parts of Zangi creek (p<0.05). The numerical abundance of macrobenthose varied from 221. m-2 in polluted area to 4346 m-2 in free part of Zangi creek. The Shanon-weaver information index varied from 0.4 in distinct area to 2.9 in reference station. The physico- chemical changes between distinct and free creeks showed significant variations such as pH, salinity and EC. Salinity and EC were significantly positive correlate to macrofauna density, whereas pH and TOM percentage indicated significantly negative correlation to density. Heavy metals concentrations in sediments were higher than water samples. Concentration pattern of heavy metals in sediments and water samples were Ni>Pb>Cd>Hg. Salinity and pH were significantly correlated to metals in sediments (p<0.01). No significant correlation were found between Macrofauna density and heavy metals (p<0.05).