356 research outputs found
Transcriptional Response of Selenopolypeptide Genes and Selenocysteine Biosynthesis Machinery Genes in Escherichia coli during Selenite Reduction
This work was supported by a United States Department of Agriculture-Cooperative State Research, Education, and Extension Service grant (no. 2009-35318-05032), a Biotechnology Research grant (no. 2007-BRG-1223) from the North Carolina Biotechnology Center, and a startup fund from the Golden LEAF Foundation to the Biomanufacturing Research Institute and Technology Enterprise (BRITE).Bacteria can reduce toxic selenite into less toxic, elemental selenium (Se0), but the mechanism on how bacterial cells reduce selenite at molecular level is still not clear. We used Escherichia coli strain K12, a common bacterial strain, as a model to study its growth response to sodium selenite (Na2SeO3) treatment and then used quantitative real-time PCR (qRT-PCR) to quantify transcript levels of three E. coli selenopolypeptide genes and a set of machinery genes for selenocysteine (SeCys) biosynthesis and incorporation into polypeptides, whose involvements in the selenite reduction are largely unknown. We determined that 5âmM Na2SeO3 treatment inhibited growth by âŒ50% while 0.001 to 0.01âmM treatments stimulated cell growth by âŒ30%. Under 50% inhibitory or 30% stimulatory Na2SeO3 concentration, selenopolypeptide genes (fdnG, fdoG, and fdhF) whose products require SeCys but not SeCys biosynthesis machinery genes were found to be induced â„2-fold. In addition, one sulfur (S) metabolic gene iscS and two previously reported selenite-responsive genes sodA and gutS were also induced â„2-fold under 50% inhibitory concentration. Our findings provide insight about the detoxification of selenite in E. coli via induction of these genes involved in the selenite reduction process.Publisher PDFPeer reviewe
A Deep Learning Approach to Predicting Collateral Flow in Stroke Patients Using Radiomic Features from Perfusion Images
Collateral circulation results from specialized anastomotic channels which are capable of providing oxygenated blood to regions with compromised blood flow caused by ischemic injuries. The quality of collateral circulation has been established as a key factor in determining the likelihood of a favorable clinical outcome and goes a long way to determine the choice of stroke care model - that is the decision to transport or treat eligible patients immediately.
Though there exist several imaging methods and grading criteria for quantifying collateral blood flow, the actual grading is mostly done through manual inspection of the acquired images. This approach is associated with a number of challenges. First, it is time-consuming - the clinician needs to scan through several slices of images to ascertain the region of interest before deciding on what severity grade to assign to a patient. Second, there is a high tendency for bias and inconsistency in the final grade assigned to a patient depending on the experience level of the clinician.
We present a deep learning approach to predicting collateral flow grading in stroke patients based on radiomic features extracted from MR perfusion data. First, we formulate a region of interest detection task as a reinforcement learning problem and train a deep learning network to automatically detect the occluded region within the 3D MR perfusion volumes. Second, we extract radiomic features from the obtained region of interest through local image descriptors and denoising auto-encoders. Finally, we apply a convolutional neural network and other machine learning classifiers to the extracted radiomic features to automatically predict the collateral flow grading of the given patient volume as one of three severity classes - no flow (0), moderate flow (1), and good flow (2)..
Production of Activated Carbon in a Multi-Functional Platform Pilot Plant
Activated carbons were produced from coconut shells as raw materials in a Multi-Functional Platform (MFP) pilot plant using the chemical activation method.. Derived activated carbon named, C1, C2, C3, C4, C5, and C6, based on the activation agent used and the heating rate employed, were compared to a commercial activated carbon based on acceptable parameters. C1, C2, C3, C4, C5 and C6 had relative hardness of 95.67%, 92.67%, 89.67, 91.6%, 90.67% and 93.33% respectively, averaging 92.26%, as compared to 95.6% relative hardness for the commercial activated carbon used. C6 the best performing activated carbon produced (using KOH and heating rate of 7.67 ÂșC/min) , had an adsorption rate of 188.68 mg Au/ h g, which was higher than the adsorption rate of the commercial activated carbon, which is 185.19 mg Au/ h g. This validates the possibility of activated carbon production commercially in Ghana
Assessment of genetic diversity for drought, heat and combined drought and heat stress tolerance in early maturing maize landraces
Open Access Article; Published online: 17 Nov 2019Climate change is expected to aggravate the effects of drought, heat and combined drought and heat stresses. An important step in developing âclimate smartâ maize varieties is to identify germplasm with good levels of tolerance to the abiotic stresses. The primary objective of this study was to identify landraces with combined high yield potential and desirable secondary traits under drought, heat and combined drought and heat stresses. Thirty-three landraces from Burkina Faso (6), Ghana (6) and Togo (21), and three drought-tolerant populations/varieties from the Maize Improvement Program at the International Institute of Tropical Agriculture were evaluated under three conditions, namely managed drought stress, heat stress and combined drought and heat stress, with optimal growing conditions as control, for two years. The phenotypic and genetic correlations between grain yield of the different treatments were very weak, suggesting the presence of independent genetic control of yield to these stresses. However, grain yield under heat and combined drought and heat stresses were highly and positively correlated, indicating that heat-tolerant genotypes would most likely tolerate combined drought and stress. Yield reduction averaged 46% under managed drought stress, 55% under heat stress, and 66% under combined drought and heat stress, which reflected hypo-additive effect of drought and heat stress on grain yield of the maize accessions. Accession GH-3505 was highly tolerant to drought, while GH-4859 and TZm-1353 were tolerant to the three stresses. These landrace accessions can be invaluable sources of genes/alleles for breeding for adaptation of maize to climate change
Early age at first childbirth and skilled birth attendance during delivery among young women in sub-Saharan Africa.
BACKGROUND:Despite the numerous policy interventions targeted at preventing early age at first childbirth globally, the prevalence of adolescent childbirth remains high. Meanwhile, skilled birth attendance is considered essential in preventing childbirth-related complications and deaths among adolescent mothers. Therefore, we estimated the prevalence of early age at first childbirth and skilled birth attendance among young women in sub-Saharan Africa and investigated the association between them. METHODS:Demographic and Health Survey data of 29 sub-Saharan African countries was utilized. Skilled birth attendance and age at first birth were the outcome and the key explanatory variables in this study respectively. Overall, a total of 52,875 young women aged 20-24âyears were included in our study. A multilevel binary logistic regression analysis was performed and the results presented as crude and adjusted odds ratios at 95% confidence interval. RESULTS:Approximately 73% of young women had their first birth when they were less than 20âyears with Chad having the highest proportion (85.7%) and Rwanda recording the lowest (43.3%). The average proportion of those who had skilled assistance during delivery in the 29 sub-Saharan African countries was 75.3% and this ranged from 38.4% in Chad to 93.7% in Rwanda. Young women who had their first birth at the age of 20-24 were more likely to have skilled birth attendance during delivery (aORâ=â2.4, CIâ=â2.24-2.53) than those who had their first birth before 20âyears. CONCLUSION:Early age at first childbirth has been found to be associated with low skilled assistance during delivery. These findings re-emphasize the need for sub-Saharan African countries to implement programs that will sensitize and encourage the patronage of skilled birth attendance among young women in order to reduce complications and maternal mortalities. The lower likelihood of skilled birth attendance among young women who had their first birth when they were adolescents could mean that this cohort of young women face some barriers in accessing maternal healthcare services
SEROPREVALENCE OF HEPATITIS B MARKERS IN A RURAL COMMUNITY IN GHANA
The seroprevalence of 2 hepatitis B virus markers, Hepatitis B surface antigen, and Hepatitis B core antibody were determined in 731 blood donors, and 1020 pregnant women in 3 hospitals in a rural community in Ghana during August 1991-July 1992 (blood donors) and August-November 1992 (pregnant women) by an Enzyme Immunoassay method. The prevalence of Hepatitis B surface antigen in the 2 groups was 19.5%, and 14% respectively. That hepatitis B virus infection is endemic in the community is borne out by the finding that 90% of the study population had serological evidence of Hepatitis B infection
A deep learning approach to predict collateral flow in stroke patients using radiomic features from perfusion images.
Collateral circulation results from specialized anastomotic channels which are capable of providing oxygenated blood to regions with compromised blood flow caused by arterial obstruction. The quality of collateral circulation has been established as a key factor in determining the likelihood of a favorable clinical outcome and goes a long way to determining the choice of a stroke care model. Though many imaging and grading methods exist for quantifying collateral blood flow, the actual grading is mostly done through manual inspection. This approach is associated with a number of challenges. First, it is time-consuming. Second, there is a high tendency for bias and inconsistency in the final grade assigned to a patient depending on the experience level of the clinician. We present a multi-stage deep learning approach to predict collateral flow grading in stroke patients based on radiomic features extracted from MR perfusion data. First, we formulate a region of interest detection task as a reinforcement learning problem and train a deep learning network to automatically detect the occluded region within the 3D MR perfusion volumes. Second, we extract radiomic features from the obtained region of interest through local image descriptors and denoising auto-encoders. Finally, we apply a convolutional neural network and other machine learning classifiers to the extracted radiomic features to automatically predict the collateral flow grading of the given patient volume as one of three severity classes - no flow (0), moderate flow (1), and good flow (2). Results from our experiments show an overall accuracy of 72% in the three-class prediction task. With an inter-observer agreement of 16% and a maximum intra-observer agreement of 74% in a similar experiment, our automated deep learning approach demonstrates a performance comparable to expert grading, is faster than visual inspection, and eliminates the problem of grading bias
Economic Analysis of Rubber Agroforestry Systems in Ghana
Even though rubber contributes massively to Ghanaâs economy, smallholder rubber farmersâ inability to wait for about 6-8 years to see the benefits constrains establishment and expansion of the rubber subsector. To lessen the waiting time to the benefits, an option exists to intercrop rubber with food crops. Cost benefits analysis of rubber/plantain intercropping system under different treatments on two experimental plots for sole crop plantain (P) and three intercropping treatments consisting of one (PR), two (PPR) and three (PPPR) rows of plantain each between two rows of rubber each were carried out to assess the most viable. Analysis using discounted cash flow was used to determine the benefit/cost ratio (BCR), net present value (NPV) in addition to internal rate of return (IRR) at 25 % interest rate. All the rubber/plantain intercropping systems (PR, PPR and PPPR) were found to be profitable from the results. The highest return of GHÈ»40, 331 (USD 9,379) per hectare from plantain over the period of two years was realized from the PPPR cropping system. Additional analysis performed to assess the profitability of rubber/plantain intercropping systems by varying the price of plantain, discount rate and the total cost of production showed that the systems were all profitable. The PPPR was the most profitable with the highest income to smallholder farmers. Extension education by the government through the Ministry of Food and Agriculture and Ghana Rubber Estates Limited and support to rubber farmers to access credit can help in farmersâ adoption of rubber agroforestry system
Environmental and socio-economic characteristics of the Kpene catchment in Northern Ghana: implications for soil and water conservation
Abstract: A detailed agro-ecosystem characterization was carried out in the Kpene catchment of the Jolo-Kwaha watershed in Northern Ghana at a scale of 1:5000. The objective was to examine the environmental and socio-economic characteristics of the Kpene area and identify the constraints on sustainable agricultural production, especially soil and water management. Environmental data, particularly land use and soil types were obtained through transect surveys while socio-economic data through participatory rural appraisal (PRA) techniques. The area falls within the Guinea Savanna agro-ecological zone of Ghana with a unimodal rainfall regime. With a Land Use Ratio (LUR) of almost 100%, land use is very intense and fallow is almost non-existent the farming system. The uplands have mainly deep, well -drained and nonconcretionary Lixisols, and the lowlands, deep and imperfectly to poorly drained Planosols and Gleysols. The Kpene community has an average of 40 persons per household, with majority (45%) being between 15-45 years of age. The major occupation is farming with land ownership being entirely through inheritance. Major crops grown are maize, yam, rice and groundnuts. In soil fertility management, 70% apply mineral fertilisers, especially to rice. Some constraints on agricultural production are erratic and unreliable rainfall, low soil fertility and poor water management. Levelling for proper water conservation in the valley bottoms and water harvesting can enhance agricultural production
Assessing the potential of extra-early maturing landraces for improving tolerance to drought, heat, and both combined stresses in maize
Open Access Journal; Published online: 25 Feb 2020Maize landrace accessions constitute an invaluable gene pool of unexplored alleles that can be harnessed to mitigate the challenges of the narrowing genetic base, declined genetic gains, and reduced resilience to abiotic stress in modern varieties developed from repeated recycling of few superior breeding lines. The objective of this study was to identify extra-early maize landraces that express tolerance to drought and/or heat stress and maintain high grain yield (GY) with other desirable agronomic/morpho-physiological traits. Field experiments were carried out over two years on 66 extra-early maturing maize landraces and six drought and/or heat-tolerant populations under drought stress (DS), heat stress (HS), combined both stresses (DSHS), and non-stress (NS) conditions as a control. Wide variations were observed across the accessions for measured traits under each stress, demonstrating the existence of substantial natural variation for tolerance to the abiotic stresses in the maize accessions. Performance under DS was predictive of yield potential under DSHS, but tolerance to HS was independent of tolerance to DS and DSHS. The accessions displayed greater tolerance to HS (23% yield loss) relative to DS (49% yield loss) and DSHS (yield loss = 58%). Accessions TZm-1162, TZm-1167, TZm-1472, and TZm-1508 showed particularly good adaptation to the three stresses. These landrace accessions should be further explored to identify the genes underlying their high tolerance and they could be exploited in maize breeding as a resource for broadening the genetic base and increasing the abiotic stress resilience of elite maize varieties
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