A Novel Reagentless Biosensor Constructed by Layer-by-Layer Assembly of HRP and Nile Blue Premixed with Polyanion

A novel reagentless biosensor constructed by the organic dye nile blue (NB) and horseradish peroxidase (HRP) has been fabricated via layer-by-layer (LBL) self-assembly technique. NB premixed with polyanion poly (sodium-p-styrenesulfonate) (PSS) acts as the mediator between the immobilized HRP and the electrode surface. The response of the biosensor to hydrogen peroxide has been investigated. The linear range of the biosensor to hydrogen peroxide was from 0.20 mmol/L to 7.03 mmol /L with a sensitivity of 8.45 μA/(mmol/L).

Low Flow Trends and Frequency Analysis in the Blue Nile Basin, Ethiopia

Low flow analysis provides crucial information for the planning and design water resource development, risk assessment and environmental flow management. Understanding the low flow regimes and evaluating the magnitudes for incorporating in water resources management is vital for the countries like Ethiopia where demand for water is increasing. However, there were hardly enough studies in understanding the trends of low flow and frequency analysis. Therefore, this study focuses on evaluation of the trends in low flows and regional low flow analysis in the Blue Nile Basin, Ethiopia. In order to carry out the study, 15 river sub-basins in the Blue Nile Basin were selected based on the long term data availability and presence of quality of data. The 3-day sustained low flow (3d-slf), the 7-day sustained low flow (7d-slf) and the 14-day sustained low flow (14d-slf) models were used to extract the data from the daily time series stream data obtained from MoWIE. Trends in low flow were analyzed separately by using Mann-Kendall (MK) trend test. Low flow frequency analysis was used to estimate the long term low flow quantiles. In addition, regional analysis for estimating the quantiles for ungaged catchments was also developed based on the regional growth curve and catchment characteristic of drainage basins. The results indicated that 3d-slf, 7d-slf and 14d-slf models of low flow series indicated no significant difference for each station at 95% CI. Out of the 15 selected stations, 12 of stations have indicated decreasing;two stations indicated increasing and remaining one station with no trend. Mainly decreasing trend was associated with the land cover and climate change which results in increasing runoff and evapotranspiration respectively. Weibull distribution—GEV and LGN was found best fit based on the L-Moment Ratio Diagram (L-MRD). Hence quantile estimations have indicated diminishing magnitudes of low flow quintiles for 2 - 500 years return periods. Regional low frequency analysis has provided a very good relationship between discharge and catchment characteristics with an R2 of 0.72. Where area (A) and rainfall (R) followed by slope were found sensitive to compute in developing the regional region equations between mean low flows and the physiographic data. This study indicated that there needs to be a new water management scenario and adaptation mechanism of climate change and land use land cover dynamics for utilizing water resource in the Blue Nile Basin.

Prediction of Groundwater Level Fluctuation towards Rainfall Induced Landslide: Case of Blue Nile Gorge, Central Ethiopia

The groundwater level fluctuation was studied in a complex geological setting region where a frequent landslide is observed in a rainy season. Steady and transient states of flow are modeled with different hydrogeological parameters. The models are calibrated to satisfy the observed field conditions and expected results from the scientific point of view. The results reveal that the groundwater level fluctuation and flow direction in the region are complex. In limited areas, the fluctuation of groundwater is significant from season to season while in others the level remains stable in all seasons of the year. Following that, the result of groundwater flow model was exported to GeoStudio to simulate the slope stability of selected slope. The factor of safety was calculated using Slope/W. The effect of pore-water on the factor of safety was cross-checked by remodeling the slope without water. The results and sensitivity analysis of slope stability confirm that the rise of groundwater level decreases the factor of safety significantly only on critical slope section.

Rainfall Partitioning for Integrated Water Resources Management： Case Study of Upper Blue Nile Basin, Ethiopia

The Upper Blue Nile Basin, the highest sources of the Nile River flow through this area, is still under severe land degradation, which aggravates water scarcity. The productivity of subsistence farming is below 50% of the potential of agriculture, mainly because of inappropriate rainwater management. At farm level, rainwater is exposed to poor partitioning described as flooding, land degradation, siltation and water scarcity for domestic, irrigation, hydropower and environmental uses in the basin. Hence, it is one of the root causes of food-insecurity in the region. To reverse this situation and achieve increased rainwater productivity knowledge of rainfall partitioning at grassroots level is significantly important. However, rainwater partitioning and partitioning points are not clearly known by farmers in the area. Besides, understanding water-routes helps to manage rainwater with integrated water resources management （IWRM） processes. The objective of this study was to identify the knowledge gap of farmers and experts on rainwater partitioning that help for increased water productivity. Intensive monitoring and interviews have been carried out for 81 farmers and 22 local experts in three pilot sites. The interviewed farmers and experts are clearly aware of the runoff partitioning, since it is easily observable. While, only 10% of the farmers and 25% of experts know about evaporation partitioning, which is the largest compared to other losses. The paper gives recommendations for better understanding of rainfall partitioning points and management of water-routes at grassroots level to increase rainwater productivity and enhance food security in the area with IWRM processes.

Validation of General Climate Models (GCMs) over Upper Blue Nile River Basin, Ethiopia

Potential of climate change impact assessment on hydrology and water resources of rivers is increasing from time to time due to its importance for water resources planning and management in the future. In order to carry out climate change impact studies, using General Climate Models (GCM) is a common practice and before using any of these models, it is essential to validate the models for the selected study area. Blue Nile River is one of the most sensitive rivers towards climate change impacts. The main source of Blue Nile River is Lake Tana where the two adjacent tributary rivers, Ribb & Gumera, are located and the main object of this paper is validation of current 15 GCM outputs (IPCC-AR5) over these two rivers using empirical quantile perturbation downscaling technique. The performance of the downscaled outputs of GCMs were evaluated using statistical indicators and graphical techniques for evapotranspiration, rainfall and temperature variables using observed daily meteorological datasets collected from five stations (Addis Zemen, Bahirdar, Debretabor, Woreta and Yifag) for the control period 1971-2000. Analysis results showed that the correlation coefficient of all models for mean monthly (MM) rainfall are 12% - 45%;and the Bias and RMSE -46 mm to +169 mm and 62 mm to 241 mm, respectively. The Bias and RMSE for MM maximum temperature are -2.5°C to +35°C;and 1°C to 35°C whereas for MM minimum temperature -6°C to +22°C and 1.7°C to 23°C, respectively. For the case of MM evapotranspiration, which is estimated using FAO-Penman-Montheith equation, the Bias and RMSE values vary from -35 mm to +10 mm;and +11 mm to +36 mm, respectively. The variation in the performance level of these models indicates that there is high uncertainty in the GCM outputs. Therefore, to use these GCM models for any climate change studies in the basin, careful selection has to be made.

新型Nile blue材料对多种客体上潜在手印显现研究

尼罗蓝类化合物是灵敏度高、生物毒性较低的吩恶嗪类荧光试剂。从尼罗蓝A(Nile blue A)的光学性能入手,考察了Nile blue A显现潜在手印时的最佳适用条件及在不同客体上的显现效果。通过连续捺印显现实验进一步探究了该方法的灵敏度和对陈旧性手印的显现能力。实验结果证实,该方法在潜在手印显现时具有较高的显现灵敏度和广泛的客体适用性,在Nile blue A质量浓度为0.03mg/mL时达到最佳,其显现手印具有显色和荧光双重效果,能够适用于大多数渗透性与非渗透性客体表面潜在手印显现,甚至对于潮湿及复杂背景客体仍具有良好的效果,为犯罪现场潜在手印的显现提供了更有效的方法。

Third Order Optical Nonlinearities and Spectral Characteristics of Methylene Blue

We have investigated third order nonlinear optical properties and spectral characteristics of methylene blue dye in both polymer and liquid mixtures. The spectral characteristics of the dye is studied by recording the absorption and fluorescence spectra of the dye doped in poly(methylmethacrylate) modified with additive n-butyl acetate(nBA) and the dye in MMA and nBA (liquid mixture). The spectral results of the dye doped polymer rod are compared with dye in liquid Mixture. The nonlinear measurements of the dye in liquid and polymer medium were performed using CW He-Ne laser of wavelength 632.8 nm by employing z-scan technique. The dye methylene blue showed a negative nonlinear refractive index.

钌（Ⅲ）－钼酸盐－耐尔蓝－PVA＿（124）体系缔合显色反应的研究

在聚乙烯醇存在下，钌与铜酸盐和耐尔蓝（ＮＢ）形成离子缔合物，缔合物的λ＿（ｍａｘ）为５８５ｎｍ，ε为１．３２×１０￣６Ｌ·ｍｏｌ·ｃｍ￣（－１），符合比耳定律范围０～１．２μｇ／２５ｍＬＲｕ，检测限为２．６ｎｇ／ｍＬ（ｎ＝１１），用平衡移动法测定缔合物的摩尔比为Ｒｕ：ＮＢ＝１：２。考察了４３种共存离子的影响，仅Ｏ＿ｓ（Ⅲ）、、Ａｓ（Ⅲ）、Ｓｂ（Ⅲ）、Ｇｅ（Ⅳ）有干扰，需用蒸馏分离。本法已用于某些岩矿和冶金产品中钌的测定，结果满意。

罗非鱼雌、雄群体遗传差异的RAPD分析

从40个随机引物中分别筛选出15和18个,对奥利亚罗非鱼和尼罗罗非鱼雌、雄群体进行RAPD分析,结果显示:奥利亚罗非鱼雌性群体的多态位点比例为56.25%,基因多样性指数为0.2358,Shannon氏指数为0.3417,群体内的遗传相似指数为0.8625;雄性群体的多态位点比例为57.50%,基因多样性指数为0.2356,Shannon氏指数为0.3418,群体内的遗传相似指数为0.8375。尼罗罗非鱼雌性群体的多态位点比例为47.44%,基因多样性指数为0.1788,Shannon氏指数为0.2637,群体内的遗传相似指数为0.7667;雄性群体的多态位点比例为64.10%,基因多样性指数为0.2347,Shannon氏指数为0.3486,群体内的遗传相似指数为0.6769。试验结果表明,奥利亚罗非鱼雌、雄性群体的遗传多样性程度接近,而尼罗罗非鱼雄性群体的遗传多样性要比雌性群体丰富,遗传变异比雌性群体大。

探针体耐尔蓝(NB)与DNA结合反应研究

应用微相吸附 -光谱修正 (MPASC)新技术研究DNA与耐尔蓝 (NB)探针分子间的相互作用 ,分析生物大分子内静电场的形成与Langmuir吸附的关联性 ,测定了结合产物结合比、平衡常数等。通过在pH =10 .38介质中对DNA -NB反应的光谱分析 ,结果表明产物结合比NB∶DNA -P =3∶1、平衡常数K =3.33× 10 5,摩尔吸收系数ε660nm=4 .81× 10 3 L/molcm。样品分析表明DNA回收率95 .6 %～ 10 8% ,相对标准偏差RSD =2 .8%。

耐尔兰A修饰碳纤维微柱电极的电化学性质研究

用循环伏安法将碳纤维微柱电极表面官能团化，利用正负离子间的静电作用将耐尔兰Ａ修饰在碳纤维微柱电极（ＣＦＭＣＥ）表面。对该修饰电极的电化学性质进行了研究，讨论了它的稳定性，测定了不同ｐＨ值下固定化耐尔兰Ａ电极反应的表现电子转移速率常数κ、电荷转移系数α以及参加电极反应的Ｈ＋数。实验表明：电极对血红蛋白在ＣＦＭＣＥ上的还原有电催化作用．

耐尔蓝A硫酸盐作探针的共振散射法测定痕量肝素钠

目的以耐尔蓝A硫酸盐为探针,建立一种共振散射(RS)技术测定痕量肝素钠的新方法。方法在pH3.29的Britton-Robinson缓冲溶液中,肝素钠与耐尔蓝A硫酸盐反应,导致体系的共振散射强度增强,最强共振散射峰为732nm。本文研究了耐尔蓝A硫酸盐-肝素钠体系的光谱特征、适宜的反应条件和共存物质的影响。结果肝素钠的浓度在0.16￣4.52μg/mL范围内与732nm处的共振散射强度增强呈良好的线性关系,其回归方程为△IRS=3.22+50.48c(R=0.9991),检出限(3σ)为3.33ng/mL,该方法已用于肝素钠注射液的分析,回收率在95.6%-104.2%之间。结论建立了一种简便、快速、灵敏的RS法测定痕量肝素钠的方法。

聚耐尔蓝/氧化石墨烯光电极对NADH的光致电化学响应

在氧化石墨烯修饰的ITO电极上,通过电聚合光敏材料耐尔蓝,构建了具有电子受体功能的光电极.该光电极能与电子供体NADH（烟酰胺腺嘌呤二核苷酸）产生光致电化学反应,通过测量反应产生的光电流实现了对NADH的检测.探讨了光致电化学响应机理,研究了氧化石墨烯固定量和耐尔蓝初始浓度对光电极性能的影响.在优化了电解质溶液pH和偏压的测试条件下,该光电极对NADH的响应范围为0.01~80.0μmol/L,检出限为7.0nmol/L,相对标准偏差小于2.73%.该光电极的制备和对NADH的检测不需要除氧,有经济、简便等优点.

KBrO_3-耐尔蓝A体系催化光度法测定痕量钒

研究了在H2SO4介质中,柠檬酸存在下,痕量V（Ⅴ）催化KBrO3氧化耐尔蓝A的褪色反应,通过测定640 nm波长下催化体系和非催化体系的吸光度,建立了催化光度法测定痕量V（Ⅴ）的新方法。方法的线性范围为0.00020-0.0040μg/mL,检出限为7.1×10^-12g/mL。已用于自来水和大米中痕量钒的测定。

Spectroscopic and Spectroelectrochemical Studies of Interaction of Nile Blue with DNA

Nile Blue can strongly bind to DNA and its affinity for DNA has beeninvestigated by spectroscopy and spectroelectrochemistry. At low DNA concentrations, Nile Blue canbind to DNA (per nucleotide phosphate) to form a 1:1 association complex with the binding constantof 4.7 * 10~4 L/mol and the major binding model of Nile Blue to DNA is 'electrostatic binding'.However, the major binding model changes into 'intercalative binding' at high DNA concentrations. Inorder to confirm which part of Nile Blue intercalating into DNA, the inclusion action ofβ-cyclodextrin (β-CD) has been used to study the interaction. Nile Blue can be included into thehydrophobic cavity of β-CD to form an inclusion complex with a stability constant of 1.9 * 10~3L/mol. The experimental results indicate that the naphthalene ring part of Nile Blue is includedinto β-CD's hydrophobic cavity and the inclusion complex decomposes at high DNA concentrations. Itmay be deduced reasonably that the naphthalene ring part of Nile Blue molecule intercalates into DNAhelix Strand.

A molecular survey on cystic echinococcosis in Sinnar area, Blue Nile state （Sudan）

Background Cystic echinococcosis （CE） is a zoonosis caused by the cestodes of the Echinococcus species. Its life cycle involves dogs and other canids as definitive hosts for the intestinal tapeworm, as well as domestic and wild ungulates as intermediate hosts for the tissue-invading metacestode （larval） stage. The disease has a special impact on disadvantaged pastoralist communities and is listed now among the three top priority neglected tropical disease （NTD）. Therefore, CE is a neglected disease even in high endemicity regions. This study aimed at investigation of the prevalence of CE in different animals slaughtered for food consumption in Sinnar area, Blue Nile states in Sudan. Methods A survey of CE in livestock was conducted from April 2009 to March 2011 in Sinnar area, Blue Nile state in Sudan. Location, parasitological status and fertility conditions were determined. In addition, 120 hydatid cysts （30 from camels, 62 from cattle and 28 from sheep） were examined by polymerase chain reaction （PCR） and mitochondrial gene sequencing for the genetic allocation of Echinococcus strains or species Results The prevalence of CE was 29.7% （30/101） in camels, 2.7% （62/2310） in cattle and 0.6% （26/4378） in sheep. It was shown that infection rates increased with age in camels, cattle and sheep. In camels, 67% （20/30） of the infected animals were aged between 2-5 years whereas 58% （36/62） of the infected cattle were 〉5 years. In sheep, the prevalence rate was distributed equally between animals ranging 2-5 years and 〉5 years. Even though multiple cysts were found in some animals, the average number of cysts per animal was close to 1 in all examined species. Lungs were found to be the predilection sites for the parasite in both camels and cattle, while most of the cysts found in sheep were located in the liver. About 63.4% of cysts encountered in camels were considered as large （5-7 cm）, whereas those in cattle and sheep were medium （2-4 cm） and small （〈2 cm） respectively. The highest fertility rate was found in camel cysts with 85.4% （35/41） followed by cattle （50.0%, 32/64） and sheep （39.0%, 11/28）. All examined cysts belonged to Echinococcus canadensis G6, which was confirmed to be the overwhelmingly predominant species in that area. Conclusion The epidemiological situation in Sinnar area, Blue Nile state is characterized by intense transmission of Echinococcus canadensis G6, thereby closely resembling the situation in most other regions of Sudan.

Electrocatalytic oxidation of NADH at glassy carbon electrodes modified with an electropolymerized film of nile blue A

The kinetic parameters for the etectrocatalytic oxidation of dihydronicotiamide adenine dinucleotide (NADH) at glassy carbon electrodes modified with an electropolymerized film of nile blue A (PNB) have been determined based on rotating disk electrode measurements. The rate constant for the chemical reaction between NADH and PNB is strongly influenced by NADH concentration and the pH value of solution, and it decreases with increasing NADH concentration, indicating that the electrocatalytic process proceeds via the formation of an intermediate of charge-transfer complex between NADH and PNB.

耐尔蓝-高碘酸钾-溴代十六烷基吡啶-氨三乙酸体系催化动力学光度法测定锰

在增敏剂溴代十六烷基吡啶和活化剂氨三乙酸存在的条件下 ,锰 对高碘酸钾氧化耐尔蓝的反应具有催化作用 ,据此建立了测定锰的新方法。该法具有很高的灵敏度和选择性。在最优化的实验条件下 ,其线性范围为 0 .4～ 5 .6 μg L ;检出限为 0 .0 5 4μg L (n =8) ;相对标准偏差为 3.8%。用于水样、蔬菜样品中锰含量的测定 ,结果令人满意。

用耐尔蓝和高碘酸盐催化光度法测定痕量铱(Ⅳ)

研究了在弱酸性介质中,利用铱(Ⅳ)催化高碘酸钾氧化耐尔蓝(NB)形成桃红色产物,建立了催化光度法测定痕量铱的新方法.方法的线性范围为4.0～40μg/L;检出限为4.0μg/L;对40μg/L Ir(Ⅳ)测定的RSD为2.02%.Os(Ⅷ)、Ru(Ⅲ)、Rh(Ⅲ)干扰,100倍量Au(Ⅲ)和Pd(Ⅱ)、40倍量Pt(Ⅳ)和很多非贵金属不干扰.本法满意地用于某些矿石和冶金产品中铱的测定.

铑(Ⅲ)-耐尔蓝-高碘酸钾体系催化动力学光度法测定痕量铑

研究了催化动力学光度法测定痕量铑。在氯化钠存在的磷酸溶液中及加热条件下，铑（Ⅲ）对高碘酸钾氧化耐尔蓝褪色的反应具有催化作用．该催化反应对耐尔蓝或铑（Ⅲ）均为一级反应，表观活化能为６１．０ｋＪ／ｍｏｌ；ｌｏｇ（Ａｏ／Ａ）与铑（Ⅲ）浓度呈线性的范围为０～６．０μｇ／２５ｍＬ，检出限为３．８０×１０－１０ｇ／ｍＬ。本法用于实际样品中铑的测定，其相对标准偏差为２．４％～７．２％，标准加入回收率为９８．２％～１０１．２％。