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.

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).

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.

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.

Assessing the costs and benefits of improved land management practices in three watershed areas in Ethiopia

Unsustainable land use management and the resulting soil erosion are among the most pervasive problems in rural Ethiopia,where most of the country’s people live,jeopardizing food security.Despite various efforts to introduce soil conservation measures and assess their costs and benefits,it is unclear how efficient these measures are from an economic point of view in securing food production.This paper examines the costs and benefits of three soil conservation measures applied in the country in three different rural districts facing different degrees of soil erosion problems using survey data collected from 750 farm households.A production function is estimated to quantify the costs and benefits of more sustainable land use management practices.We show that the soil conservation measures significantly increase productivity and hence food security.Comparing the costs and benefits,the results indicate that implementing soil conservation measures would benefit farm communities in the case study areas through increased grain productivity and food security.

Changes in ecosystem service values strongly influenced by human activities in contrasting agro-ecological environments

Background:Evaluating the impacts of land-use/land-cover(LULC)changes on ecosystem service values(ESVs)is essential for sustainable use and management of ecosystems.In this study,we evaluated the impact of human activity driven LULC changes on ESVs over the period 1982–2016/17 in contrasting agro-ecological environments:Guder(highland),Aba Gerima(midland),and Debatie(lowland)watersheds of the Upper Blue Nile basin,Ethiopia.Results:During the study period,the continuous expansion of cultivated land at the expense of natural vegetation(bushland,forest,and grazing land)severely reduced the total ESV by about US$58 thousand(35%)in Aba Gerima and US$31 thousand(29%)in Debatie watersheds.In contrast,the unprecedented expansion of plantations,mainly through the planting of Acacia decurrens,led,from 2006,to a ESV rebound by about US$71 thousand(54%)in Guder watershed,after it had decreased by about US$61 thousand(32%)between 1982 and 2006.The reduction in natural forest area was the major contributor to the loss of total ESV in the study watersheds,ranging from US$31 thousand(63%)in Debatie to US$96.9 thousand(70%)in Guder between 1982 and 2016/17.On an areaspecific basis,LULC changes reduced the average ESV from US$560 ha^(−1) year^(−1)(1982)in Guder to US$306 ha^(−1) year^(−1)(2017)in Debatie watersheds.Specific ESVs such as provisioning(mainly as food production)and regulating services(mainly as erosion control and climate regulation)accounted for most of the total ESVs estimated for the study watersheds.Conclusions:In most cases,the total and specific ESVs of the watersheds were negatively associated with the population growth,which in turn was positively associated with the expansion of cultivated land over the study period.In Guder,however,ESVs were positively associated with population growth,especially after 2012.This is mainly due to the expansion of Acacia decurrens plantations.Our results suggest,therefore,that future policy measures and directions should focus on improving vegetation cover through planting multipurpose trees such as Acacia decurrens to prevent future loss of ESV in the midland and lowland regions of the Upper Blue Nile basin and beyond.However,caution must be taken during plantation of invasive species as they may have undesirable consequences.