Contributions of Fisheries for Food and Nutrition Security: A Review with Ethiopian Contexts

In Ethiopia, mainly fish productions are from Great Rift Valley lakes and in some other northern parts of the country.  Despite the potential of fish production its fish consumption is insignificant and found to play little role in the households’ livelihood. The demand for fish in the country is increasing; however, the supply side is not increasing with large opportunities to produce.  For The consumption pattern and demand is increasing. The total fish production of the country accounts less than 1 percent of total production in Sub-Saharan African countries. Therefore with a little contribution for food and nutrition security the fishery sector has challenges related to existing climate changes, mismanagement fishery resources, lack of timely policies and institution and other technical backups related to loose rules and regulations. There are numerous explanations ascribing to the low and poor production due to inappropriate and not advancing fishing methods, economic disabilities related to infrastructures like preservation technologies. The absence of appropriate managements has been affecting the utilization of fishery resources. Thus future works has to give due attentions to exploit the fish production potentials and enhance the contributions to food and nutrition security. DOI: 10.7176/FSQM/108-04 Publication date:May 31st 202

Estudo de células solares híbridas de Si-NC/P3HT

Mestrado em Ciência e Engenharia dos MateriaisNeste trabalho são estudadas células solares híbridas formadas por poli(3- hexiltiofeno-2,5-diyl) (P3HT) como condutor orgânico de buracos e nanocristais de silício (Si-NCs) como conductor de electrões inorgânico. Células solares híbridas têm atraído muita atenção nos últimos anos devido ao facto de serem potencialmente fabricadas a baixo custo, a sua flexibilidade e baixo peso. As possibilidades de processamento em solução e ajuste da região espectral de absorção, a baixa toxicidade, e a abundância fazem dos Si-NCs um material atractivo para aplicação em células solares. Si-NCs de elevada qualidade podem hoje em dia ser produzidos em larga escala a partir da fase gasosa através da decomposição de silano num plasma. Embora a superfícies destes Si-NCs seja terminada com ligações Si-H durante a sua síntese, estes desenvolvem uma camada de óxido na superfície quando são expostos ao ar. Até agora, células híbridas de Si-NC/P3HT foram fabricadas com Si- NCs que não foram expostos ao ar após a sua síntese e foram posteriormente estudadas em condições de atmosfera inerte, devido à expectativa de que a exposição ao ar resulta na sua degradação. No entanto, o processamento de dispositivos em atmosfera inerte impõe limitações em termos técnicos e custo. Nesta tese estudamos o efeito do processamento em atmosfera de ar na performance e degradação de células solares híbridas de Si-NC/P3HT. As células foram fabricadas em ar e em atmosfera de azoto e caracterizadas à temperatura ambiente e condições de exposição ao ar. Para produzir a células solares foram usados Si-NCs que foram expostos ao ar após a síntese e que por isso contêm uma camada de óxido na sua superfície. Para remover esta camada, nós usamos um método de erosão química com uma solução diluída de ácido hidroflurico (HF). Células solares fabricadas com uma mistura de 1:1 em percentagem de peso (wt.%) de Si-NC:P3HT não revelaram qualquer efeito fotovoltaico. Dispositivos fabricados com uma mistura de 2:1 wt.% de Si-NC:P3HT mostraram efeito fotovoltaico, devido à formação de uma rede interpenetrara de Si-NC e P3HT em toda a extensão do filme foto activo, tal como revelado em imagens de microscopia electrónica de varrimento. Dispositivos fabricados em atmosfera inerte não revelaram uma performance melhorada em relação aos dispositivos produzido em atmosfera de ar, indicando que a fabricação das células solares em ar não é o factor determinante da performance das nossas células solares. Células solares que mostraram um efeitos fotovoltaico degradaram-se rapidamente por exposição ao ar. Em contrate, filmes de P3HT e de misturas Si-NC/P3HT, estudados em experiências separadas, não revelaram uma degradação significativa por exposição ao ar. Estes resultados indicma que a degradação das células solares não deve resultar da degradação da camada foto activa de Si-NC/P3HT, mas poderá resultar da degradação de interfaces entre as varias camadas que compõem as células. Medidas de ressonância paramagnética electrónica (RPE) foram levadas a cabo com os Si-NCs usados nas nossas células e com Si-NCs usados para fabricar as células estudadas em trabalhos publicados anteriormente por outros grupos. Estas medidas revelaram que o número de defeitos superficiais por nanocristal nos nossos Si-NCs é cerca de três ordens de grandeza superior ao número encontrado nos Si- NCs usados anteriormente. Este facto poderá explicar a baixa performance fotovoltaica os nossos dispositivos.We study-air-processed organic-inorganic hybrid solar cells, which incorporate poly(3-hexylthiophene-2,5-diyl) (P3HT) as organic hole conductor and silicon nanocrystals (Si-NCs) as inorganic electron conductor. Hybrid solar cells have received a lot of attention in recent years due to their low cost, flexibility and lightweight. Solution processability, nontoxicity, abundance and tunable absorption spectral range of Si-NCs make them attractive materials for application in solar cells. High quality Si-NCs can now a days be produced in large amounts from the gas phase decomposition of silane in a plasma. Although the surface of these Si-NCs is terminated with Si-H bonds immediately after synthesis, they develop an insulating native oxide shell after being exposed to air. So far, Si-NC/P3HT hybrid solar cells have only been fabricated using Si-NCs that have not been exposed to air after synthesis and afterwards characterized under inert atmosphere conditions due to the expectation that air exposure of the devices leads to their degradation. However, inert atmosphere processing has some technical and cost efficiency limitations. In this thesis, we study the effect of air-processing on the performance and degradation of solar cells based on Si-NC/P3HT. Hybrid solar cells were fabricated in air and under nitrogen ambient and characterized at room temperature under atmospheric air. To produce our solar cells we use Si-NCs that have been stored in air after plasma synthesis and, therefore, contain a native oxide at their surface. To remove this oxide layer we apply wet etching with a dilute hydrofluoric acid (HF) solution. Solar cells made from 1:1 wt.% (HF-etched Si-NC:P3HT) composition did not show detectable photovoltaic effect. A very small photovoltaic effect has been observed for devices made from 2:1 wt.% (HF-etched Si-NC:P3HT) composition as a result of the formation of an interpenetrated network throughout the photoactive film at higher NC concentration as seen from scanning electron microscopy. Device fabrication under inert atmosphere did not result in improved solar cell performance. This shows that fabrication of the devices in air was not the main reason for the poor performance of the hybrid solar cells. Moreover, solar cells that exhibited a photovoltaic effect were found to degrade within one day of air exposure. In contrast to this, the conductivity of P3HT, (unetched Si-NC)/P3HT and (HF-etched Si-NC)/P3HT films, studied in separate experiments, did not show significant degradation upon air exposure. These results indicate that the degradation of the solar cells is not due to degradation of individual photoactive layers, but could rather originate from degradation of interfaces between the different layers. Electron paramagnetic resonance measurements carried out with our Si- NCs and with Si-NCs used in previous investigations of Si-NC/P3HT solar cells revealed that the number of surface defects per NC is about three orders of magnitude larger in our NCs than in those used in the previous investigations. This could be a reason for the poor performance of our Si- NC/P3HT hybrid solar cells

Nile tilapia (\u3ci\u3eOreochromis niloticus\u3c/i\u3e) fried in recycled palm oil: implications for nutrition and health

Fish constitutes a occasional food for the Sidama people of Hawassa, the capital city of Ethiopia’s Sidama Region and the site of a large endorheic lake. Freshly-caught fish, especially Nile tilapia or koroso in Local name, are typically fried prior to consumption. Despite the sensory qualities, fried foods are not always advisable due to the impact of frying on the nutritional quality of food. This study was designed to assess the nutritional quality of Nile tilapia that had been fried in the same palm oil over six consecutive frying cycles. The raw fish were purchased from the Lake Hawassa fish market and fried at Hawassa University by simulating local preparation methods. A gas chromatography- mass spectrophotometer (GCMS) was used for the fatty acid profile analysis and a total of 22 fatty acids were elucidated. The nutritional quality indices of fatty acids was determined by calculating the recommended formula and JMP pro 13 was used for statistical analysis. The study results revealed that the tilapia fried in the oldest, most used oil, cycles 3–6, contained high amounts of saturated and trans fatty acids, as well as high atherogenic and thrombogenic indices; however, it was also lower in essential and cis fatty acids, the hypocholesterolemic/hypercholesterolemic ratio, the per-oxidizability index, and the nutritive value index. Conversely, fish prepared earlier (cycles 1–3) with fresher oil were higher in essential fatty acids and cis fatty acids, while the hypocholesterolemic/hypercholesterolemic ratio, the per-oxidizability index, and the nutritive value index were also high. Fish fried in an earlier cycle were also low in saturated and trans-fatty acids, with a lower atherogenic index, and thrombogenic index. Therefore, it can be concluded that repeatedly using the same frying oil to prepare Nile tilapia contributed to the loss of nutritional value. Results suggest that palm oil should be limited to no more than three frying cycles to maximize nutritional intake in of fish consumption

Laser-Patternable Graphene Field Emitters for Plasma Displays

This paper presents a plasma display device (PDD) based on laser-induced graphene nanoribbons (LIGNs), which were directly fabricated on polyimide sheets. Superior field electron emission (FEE) characteristics, viz. a low turn-on field of 0.44 V/μm and a large field enhancement factor of 4578, were achieved for the LIGNs. Utilizing LIGNs as a cathode in a PDD showed excellent plasma illumination characteristics with a prolonged plasma lifetime stability. Moreover, the LIGN cathodes were directly laser-patternable. Such superior plasma illumination performance of LIGN-based PDDs has the potential to make a significant impact on display technology

Improved Field Electron Emission Properties of Phosphorus and Nitrogen Co-Doped Nanocrystalline Diamond Films

Nanocrystalline diamond (NCD) field emitters have attracted significant interest for vacuum microelectronics applications. This work presents an approach to enhance the field electron emission (FEE) properties of NCD films by co-doping phosphorus (P) and nitrogen (N) using microwave plasma-enhanced chemical vapor deposition. While the methane (CH4) and P concentrations are kept constant, the N(2)concentration is varied from 0.2% to 2% and supplemented by H-2. The composition of the gas mixture is tracked in situ by optical emission spectroscopy. Scanning electron microscopy, atomic force microscopy (AFM), transmission electron microscopy, and Raman spectroscopy are used to provide evidence of the changes in crystal morphology, surface roughness, microstructure, and crystalline quality of the different NCD samples. The FEE results display that the 2% N(2)concentration sample had the best FEE properties, viz. the lowest turn-on field value of 14.3 V/mu m and the highest current value of 2.7 mu A at an applied field of 73.0 V/mu m. Conductive AFM studies reveal that the 2% N(2)concentration NCD sample showed more emission sites, both from the diamond grains and the grain boundaries surrounding them. While phosphorus doping increased the electrical conductivity of the diamond grains, the incorporation of N(2)during growth facilitated the formation of nano-graphitic grain boundary phases that provide conducting pathways for the electrons, thereby improving the FEE properties for the 2% N(2)concentrated NCD films

Fatty Acid-Related Health Lipid Index of Raw and Fried Nile Tilapia (Oreochromis niloticus) Fish Muscle

Fried food consumption is popular in most parts of the world including Ethiopia. Among many fried products available in Ethiopia, fried fish is most commonly consumed in Hawassa Town due to the easy access to the fish from the lake. Recently, there is growing concern among fryers to recycle the oil while frying fish. However, there is limited evidence about the frying effect on the fatty-acid-related health lipid index of fried fish. Thus, the study was aimed to determine the fatty acid profile and the fatty-acid-related health lipid of raw and fried fish. Raw and fried fish were taken from the Hawassa open fish market. Fatty acid profiles were analyzed using a gas chromatography-mass spectrophotometer (GCMS), and the health lipid index was determined by calculation using the recommended formula. JMP pro 13 version software was used for data analysis. Our result showed that raw fish had a high amount of essential fatty acid, nutritive value index, hypocholesterolemic ratio, and peroxidizability index. In contrary to this, the fried fish had a high amount of trans-fatty acids, nonessential fatty acids, atherogenic index, and thrombogenic index. In conclusion, the fried fish loses its fatty-acid-related nutritional quality in uncontrolled frying conditions. Therefore, frying needs to be controlled, as it risks human health otherwise

Nile tilapia (Oreochromis niloticus) fried in recycled palm oil: implications for nutrition and health

Fish constitutes a occasional food for the Sidama people of Hawassa, the capital city of Ethiopia’s Sidama Region and the site of a large endorheic lake. Freshly-caught fish, especially Nile tilapia or koroso in Local name, are typically fried prior to consumption. Despite the sensory qualities, fried foods are not always advisable due to the impact of frying on the nutritional quality of food. This study was designed to assess the nutritional quality of Nile tilapia that had been fried in the same palm oil over six consecutive frying cycles. The raw fish were purchased from the Lake Hawassa fish market and fried at Hawassa University by simulating local preparation methods. A gas chromatography-mass spectrophotometer (GCMS) was used for the fatty acid profile analysis and a total of 22 fatty acids were elucidated. The nutritional quality indices of fatty acids was determined by calculating the recommended formula and JMP pro 13 was used for statistical analysis. The study results revealed that the tilapia fried in the oldest, most used oil, cycles 3–6, contained high amounts of saturated and trans fatty acids, as well as high atherogenic and thrombogenic indices; however, it was also lower in essential and cis fatty acids, the hypocholesterolemic/hypercholesterolemic ratio, the per-oxidizability index, and the nutritive value index. Conversely, fish prepared earlier (cycles 1–3) with fresher oil were higher in essential fatty acids and cis fatty acids, while the hypocholesterolemic/hypercholesterolemic ratio, the per-oxidizability index, and the nutritive value index were also high. Fish fried in an earlier cycle were also low in saturated and trans-fatty acids, with a lower atherogenic index, and thrombogenic index. Therefore, it can be concluded that repeatedly using the same frying oil to prepare Nile tilapia contributed to the loss of nutritional value. Results suggest that palm oil should be limited to no more than three frying cycles to maximize nutritional intake in of fish consumption

Effect of nutrition education on improving dietary diversity of children aged 6–23 months in Horo district, Oromia region, Ethiopia

Background: Unmet minimum dietary diversity (MDD) feeding practices in poor nations place children at high risk of undernutrition and its related effects, which are far-reaching and difficult to correct later in life. Objective: This study aimed to assess the effect of maternal nutrition education and another determinant on the dietary diversity of children aged 6–23 months. Methods: A community-based cluster randomized trial study design was conducted from July 2019 to January 2020 in the Horo district. Twenty-three kebeles were assigned to two clusters. From two clusters, two kebeles were selected by simple random sampling. Two kebeles were assigned as intervention (150) and control (150) groups by the lottery method, at the end of the line as intervention (139) and control (137) groups. Simple random sampling techniques were used to select the study subjects. The nutrition education intervention, which lasted three months and consisted of eight sessions, was given to the intervention group, which was made up of mothers and other caregivers of children aged 6–23 months.Data entry into Epi-data and analysis were done using IBM SPSS version 26 computer software. At a 95% confidence level, values with P ≤ 0.05 were considered statistically significant. B-ivariable and multivariable conditional fixed-effect logistic regression analyses were done to identify the determinants of the dietary diversity score. Variables with a p-value of less than 0.05 were considered statistically significant. The crude odds ratio (COR) and adjusted odds ratio (AOR) were used to describe the strength and direction of the association. Result: The result was that the proportion of children with a good dietary diversity score was 52 (34.7%) and 40 (26.7%) in the control group and intervention groups at baseline, respectively. Household food security [AOR = 4.06, 95% CI: (2.45, 6.73] and being in the intervention group [AOR = 1.90, 95% CI: (1.10, 3.29] were both positive predictors of the dietary diversity score, while maternal age (35–45 years) was a negative predictor. Conclusion: At baseline, a high proportion of children aged 6–23 months did not receive the World Health Organization's minimum dietary diversity recommendation for both groups. The consumption of animal sources and vitamin-A-rich fruits and vegetables was poor among both groups. At the end of the day, after nutrition education, the dietary diversity score improved in the intervention groups but not in the control groups. New strategies and programs should be made at all levels to improve childhood nutritional status. This includes providing nutrition education for mothers aged between 35 and 45 years old

Prevalence and antimicrobial susceptibility pattern of Enterococcus species isolated from different clinical samples at Black Lion Specialized Teaching Hospital, Addis Ababa, Ethiopia

Abstract Objective Enterococci which are parts of the normal intestinal flora are opportunistic human pathogens. Their increasing importance is largely due to their resistance to antimicrobials. So the aim this study was to determine the prevalence and antimicrobial pattern of Enterococcus spp. Result From the total of 422 samples processed, 15 Enterococcus species were isolated. In this study, linezolid were the drug of choice for Enterococcus species, which showed 100% sensitive followed by vancomycin 93.3% sensitive. In contrast, highly resistance (80%) was observed for ampicillin followed by doxycycline (73.3%). All of isolated Enterococci were sensitive to linezolid, however, resistance was observed to common antibiotics. The presence of multidrug resistant Enterococci in our study should be considered as an alarm for Enterococcal infections

Nanomolded buried light-scattering (BLiS) back-reflectors using dielectric nanoparticles for light harvesting in thin-film silicon solar cells

The article presents a nanoparticle-based buried light-scattering (BLiS) back-reflector design realized through a simplified nanofabrication technique for the purpose of light-management in solar cells. The BLiS structure consists of a flat silver back-reflector with an overlying light-scattering bilayer which is made of a TiO2 dielectric nanoparticles layer with micron-sized inverted pyramidal cavities, buried under a flat-topped silicon nanoparticles layer. The optical properties of this BLiS back-reflector show high broadband and wide angular distribution of diffuse light-scattering. The efficient light-scattering by the buried inverted pyramid back-reflector is shown to effectively improve the short-circuit-current density and efficiency of the overlying n-i-p amorphous silicon solar cells up to 14% and 17.5%, respectively, compared to the reference flat solar cells. A layer of TiO2 nanoparticles with exposed inverted pyramid microstructures shows equivalent light scattering but poor fill factors in the solar cells, indicating that the overlying smooth growth interface in the BLiS back-reflector helps to maintain a good fill factor. The study demonstrates the advantage of spatial separation of the light-trapping and the semiconductor growth layers in the photovoltaic back-reflector without sacrificing the optical benefit