Genetic Diversity of Selected Upland Rice Genotypes (Oryza sativa L.) for Grain Yield and Related Traits

Seventy-seven upland rice genotypes including popular cultivars in Nigeria and introduced varieties selected from across rice-growing regions of the world were evaluated under optimal upland ecology. These genotypes were characterised for 10 traits and the quantitative data subjected to Pearson correlation matrix, Principal Component Analysis and cluster analysis to determine the level of diversity and degree of association existing between grain yield and its related component traits. Yield and most related component traits exhibited higher PCV compared to growth parameters. Yield had the highest PCV (41.72%) while all other parameters had low to moderate GCV. Genetic Advance (GA) ranged from 9.88% for plant height at maturity to 41.08% for yield. High heritability estimates were recorded for 1000 grain weight (88.71%), days to 50% flowering (86.67%) and days to 85% maturity (71.98%). Furthermore, grain yield showed significant positive correlation with days to 50% flowering and number of panicles m-2. Three cluster groups were obtained based on the UPGMA and the first three principal components explained about 64.55% of the total variation among the 10 characters. The PCA results suggests that characters such as grain yield, days to flowering, leaf area and plant height at maturity were the principal discriminatory traits for this rice germplasm indicating that selection in favour of these traits might be effective in this population and environment

Physiological responses of cowpea simultaneously exposed to water deficit stress and varying light intensities at vegetative and reproductive growth stages

A combination of stresses as it occurs on the field poses more challenges to crop production than individual stress. Crops’ response to single stress also differs from that of combined stresses. The morpho-physiological responses of two cowpea varieties (IT89KD-288 and IT99K573-1-1) to a combination of stresses (water deficit stress and high light intensity) were investigated at different growth stages. Three levels of light intensities (L3: 259 Lux- 36%, L2: 394 Lux-55% and L1: 710.2 Lux-100%) were imposed using one, two and zero layer(s) of the net, respectively, while, water deficit stress at four levels (W1: no water stress; 0-5 bars, W2: moderate water stress; 5-15 bars, W3: moderately-severe; 15-40 bars and W4: severe water stress; 40 -70 bars) was imposed differently at vegetative and reproductive growth stages. Data were collected on the cowpea yield, Leaf Temperature (LT), Chlorophyll (C), Photosynthesis (P), Stomatal Conductance (SC) and Canopy Transpiration Rate (CTR). Exposure to W4 under L1 considerably reduced cowpea yield by 80% compared to those grown under L3 and full watering. Reduced light intensity enhanced cowpea grain yield irrespective of water deficit stress and IT89KD-288 was superior to IT99K573-1-1. Reduction in light intensity also increased the SC from 55.18 in L1 to 76.88 in 36 % L3. Full light intensity without water stress (100% light intensity), increased C content, while severe water stress reduced the C content and CTR. Photosynthesis was, however, reduced under low light intensity compared to 100% light intensity. It was also observed that water deficit stress imposed at the reproductive stage did not affect P, CTR and SC unlike that of the vegetative stage. In conclusion, reduced light intensity enhanced cowpea tolerance to water deficit and increased yield. Cowpea response was dependent on growth stage, variety and severity of stress

Special Issue "Selected Papers from the 2018 IEEE International Conference on High Voltage Engineering (ICHVE 2018)"

Articles sélectionnés, ICHVE 2018, Conférence internationale, Ingénierie de haute tension, IEE

responder analysis based on patient reported outcomes pros and clinical endpoints ceps in patients pts with metastatic merkel cell carcinoma mmcc treated with avelumab

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Hepatitis C virus cell-cell transmission and resistance to direct-acting antiviral agents

Hepatitis C virus (HCV) is transmitted between hepatocytes via classical cell entry but also uses direct cell-cell transfer to infect neighboring hepatocytes. Viral cell-cell transmission has been shown to play an important role in viral persistence allowing evasion from neutralizing antibodies. In contrast, the role of HCV cell-cell transmission for antiviral resistance is unknown. Aiming to address this question we investigated the phenotype of HCV strains exhibiting resistance to direct-acting antivirals (DAAs) in state-of-the-art model systems for cell-cell transmission and spread. Using HCV genotype 2 as a model virus, we show that cell-cell transmission is the main route of viral spread of DAA-resistant HCV. Cell-cell transmission of DAA-resistant viruses results in viral persistence and thus hampers viral eradication. We also show that blocking cell-cell transmission using host-targeting entry inhibitors (HTEIs) was highly effective in inhibiting viral dissemination of resistant genotype 2 viruses. Combining HTEIs with DAAs prevented antiviral resistance and led to rapid elimination of the virus in cell culture model. In conclusion, our work provides evidence that cell-cell transmission plays an important role in dissemination and maintenance of resistant variants in cell culture models. Blocking virus cell-cell transmission prevents emergence of drug resistance in persistent viral infection including resistance to HCV DAAs

Apolipoprotein E mediates evasion from hepatitis C virus−neutralizing antibodies

Background & Aims Efforts to develop an effective vaccine against hepatitis C virus (HCV) have been hindered by the propensity of the virus to evade host immune responses. HCV particles in serum and in cell culture associate with lipoproteins, which contribute to viral entry. Lipoprotein association has also been proposed to mediate viral evasion of the humoral immune response, though the mechanisms are poorly defined. Methods We used small interfering RNAs to reduce levels of apolipoprotein E (apoE) in cell culture−derived HCV−producing Huh7.5-derived hepatoma cells and confirmed its depletion by immunoblot analyses of purified viral particles. Before infection of naïve hepatoma cells, we exposed cell culture−derived HCV strains of different genotypes, subtypes, and variants to serum and polyclonal and monoclonal antibodies isolated from patients with chronic HCV infection. We analyzed the interaction of apoE with viral envelope glycoprotein E2 and HCV virions by immunoprecipitation. Results Through loss-of-function studies on patient-derived HCV variants of several genotypes and subtypes, we found that the HCV particle apoE allows the virus to avoid neutralization by patient-derived antibodies. Functional studies with human monoclonal antiviral antibodies showed that conformational epitopes of envelope glycoprotein E2 domains B and C were exposed after depletion of apoE. The level and conformation of virion-associated apoE affected the ability of the virus to escape neutralization by antibodies. Conclusions In cell-infection studies, we found that HCV-associated apoE helps the virus avoid neutralization by antibodies against HCV isolated from chronically infected patients. This method of immune evasion poses a challenge for the development of HCV vaccines

Potential of determining moisture content in mineral insulating oil by fourier transform infrared spectroscopy

Transformer oils are vulnerable to moisture, which can have adverse effects including a dramatic reduction in dielectric strength, accelerating the aging of the solid insulation (cellulose depolymerization) and the formation of decompositional gasses at high temperatures. Moisture may be generated inside the transformer due to degradation of the oil-paper insulation or there may be ingress of moisture due to free-breathing arrangements. A moisture content exceeding 50% of oil saturation greatly reduces the breakdown voltage, resulting in catastrophic failures as well as the potential for transformer fires [1]. The detrimental effect of water within a transformer is not only limited to the breakdown voltage of the oil. The rate of degradation of paper insulation increases in direct proportion to the water content [2], [3]. Moisture also has a decisive effect on the maximum temperature that the transformer can run at before moisture-induced failure occurs. Consequently, transformer life expectancy can be calculated from water content and temperature [3]. A failure of transformer accessories such as condenser bushings sometimes leads to a transformer failure and long-term outage. Often, moisture is a cause of explosion for service-aged bushings