Fisheries Centre Research Reports, Vol. 20, No. 1

Science, Faculty ofOceans and Fisheries, Institute for theUnreviewedFacultyGraduat

Fabrication of dual function disposable substrates for spectroelectrochemical nanosensing

In this work, we demonstrate the fabrication of disposable and field deployable nanostructured conductive substrates for dual detection by Surface Enhanced Raman Scattering (SERS) and electrochemistry. Using a one-step potentiostatic process, gold nanostructures were electrodeposited on three substrates: bare indium tin oxide (ITO) electrode, ITO coated with plane gold and carbon fibre (CF) covered with ZnO nanowires (ZnO NWs). Their sensitivities were enhanced by incorporating the plane gold layer and ZnO NWs. The intensity of SERS signals produced on the nanostructured ITO substrates with 0.1µM quinolinethiol were of the order: nanostructured gold-coated ITO > nanostructured bare ITO. The higher SERS signal on the nanostructured gold-coated ITO was attributed to the coupling between the surface plasmon polariton provided by the gold under layer and the surface plasmon resonance of the Au nanostructures. The ZnO NWs on the carbon fibre provided additional surface area for electrodeposition of gold nanostructures at high density. This led to multiple hotspots formation yielding high SERS signal intensity relative to that on a nanostructured bare carbon fibre. The nanostructured substrates, demonstrated good SERS signal reproducibility with relative standard deviation of 5.19%, 3.28% and 4.53% for Au/ITO, Au/Au-ITO and Au/ZnO-CF respectively. To demonstrate the potential application of these substrates and estimate their sensitivities, they were used to detect melamine by SERS at 1 pM (for Au nanostructures on bare ITO), 1 fM (for Au nanostructured gold-coated ITO), and 0.1 nM (for Au nanostructures on ZnO NWs-coated CF) concentrations with LOD of 0.118 pM, 0.189 fM and 57.4 pM respectively. Taking advantage of the conductive properties of gold nanostructured ITOs, electrochemical detection of 0.1 µM melamine (with an LOD of 0.05 µM) was also demonstrated. Hence, these substrates are potentially useful for SERS and electrochemical-based detection of organic toxicants

Seroprevalence of transfusion-transmissible infections among blood donors at National Blood Transfusion Service, Eritrea: a seven-year retrospective study

Abstract Background Blood transfusion is associated with several risks particularly exposure to blood transfusion-transmissible infections (TTI), including: Hepatitis B virus (HBV), Hepatitis C virus (HCV), Human immunodeficiency virus (HIV) and Syphilis, among others. The threat posed by these blood-borne pathogens is disproportionately high in Sub-Saharan Africa (SSA). This fact underscores the need for continuous surveillance of TTIs in the region. Therefore, the study objectives were to evaluate the prevalence of TTIs and donor characteristics associated with positivity for TTIs at the National Blood Transfusion Center (NBTC) in Asmara, Eritrea. Methods A retrospective analysis of blood donors’ records covering the period from January 2010 to December 2016 was undertaken. The records were analyzed to evaluate the annualised cumulative prevalence of TTIs. Chi-square test (χ2) or Fisher’s exact test was used to evaluate the relationship between serological positivity and particular donor characteristics. Logistic regression was fitted to identify factors associated with cumulative TTIs positivity. A P-value < 0.05 was considered statistically significant. Result A total of 60,236 consecutive blood donors were screened between 2010 and 2016. At least 3.6% of donated blood was positive for at least one TTI and 0.1% showed evidence of multiple infections. The sero-prevalence of HBV, HCV, HIV, syphilis and co-infection was 2.0, 0.7, 0.3 and 0.6%, respectively. Sex, type of donor and region were associated with TTI positivity. Except for donation frequency, there was a significant relationship (P < 0.005) between HBV, HCV, HIV and syphilis sero-positivity and other donor characteristics evaluated in the study. Conclusion The result demonstrates that Eritrea has relatively low TTI prevalence compared to other countries in Sub-Saharan Africa. However, the prevalence, particularly that of HCV, increased significantly in 2016. Enhancing donor screening and additional research utilizing nucleic acid based techniques should therefore be prioritized

Not Available

Not AvailableThe extinction risk of sharks, rays and chimaeras is higher than that for most other vertebrates due to low intrinsic population growth rates of many species and the fishing intensity they face. The Arabian Sea and adjacent waters border some of the most important chondrichthyan fishing and trading nations globally, yet there has been no previous attempt to assess the conservation status of species occurring here. Using IUCN Red List of Threatened Species Categories and Criteria and their guidelines for application at the regional level, we present the first assessment of extinction risk for 153 species of sharks, rays and chimaeras. Results indicate that this region, home to 15% of described chondrichthyans including 30 endemic species, has some of the most threatened chondrichthyan populations in the world. Seventy‐eight species (50.9%) were assessed as threatened (Critically Endangered, Endangered or Vulnerable), and 27 species (17.6%) as Near Threatened. Twenty‐nine species (19%) were Data Deficient with insufficient information to assess their status. Chondrichthyan populations have significantly declined due to largely uncontrolled and unregulated fisheries combined with habitat degradation. Further, there is limited political will and national and regional capacities to assess, manage, conserve or rebuild stocks. Outside the few deepsea locations that are lightly exploited, the prognosis for the recovery of most species is poor in the near‐absence of management. Concerted national and regional management measures are urgently needed to ensure extinctions are avoided, the sustainability of more productive species is secured, and to avoid the continued thinning of the regional food security portfolio.Not Availabl

Not Available

Not AvailableThe extinction risk of sharks, rays and chimaeras is higher than that for most other vertebrates due to low intrinsic population growth rates of many species and the fishing intensity they face. The Arabian Sea and adjacent waters border some of the most important chondrichthyan fishing and trading nations globally, yet there has been no previous attempt to assess the conservation status of species occurring here. Using IUCN Red List of Threatened Species Categories and Criteria and their guidelines for application at the regional level, we present the first assessment of extinction risk for 153 species of sharks, rays and chimaeras. Results indicate that this region, home to 15% of described chondrichthyans including 30 endemic species, has some of the most threatened chondrichthyan populations in the world. Seventy‐eight species (50.9%) were assessed as threatened (Critically Endangered, Endangered or Vulnerable), and 27 species (17.6%) as Near Threatened. Twenty‐nine species (19%) were Data Deficient with insufficient information to assess their status. Chondrichthyan populations have significantly declined due to largely uncontrolled and unregulated fisheries combined with habitat degradation. Further, there is limited political will and national and regional capacities to assess, manage, conserve or rebuild stocks. Outside the few deepsea locations that are lightly exploited, the prognosis for the recovery of most species is poor in the near‐absence of management. Concerted national and regional management measures are urgently needed to ensure extinctions are avoided, the sustainability of more productive species is secured, and to avoid the continued thinning of the regional food security portfolio.Not Availabl