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 (sodiu...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).展开更多
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...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。展开更多
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:...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.展开更多
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 determine...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.展开更多
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 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.展开更多
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 magnitude...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.展开更多
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 hydrogeolog...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.展开更多
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 car...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.展开更多
文摘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).
文摘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。
基金theNationalNaturalScienceFoundationofChina (No .2 9835 110 )andtheDoctoralFoundationoftheNationalE ducationMinistryofChina (No .980 2 8435 )
文摘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.
基金Project supported by the Naural Science Foundation of the Education Commission of Jiangsu Province.
文摘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.
文摘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.
文摘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.
文摘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.
文摘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.
