298 research outputs found

    Structural flax/PLA biocomposites: understanding of their thermo-mechanical behaviour.

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    The extended use of bio-composites for the manufacturing of vehicle components would largely benefit the industry. However, the properties of biocomposites, their mechanical performance under different environments and the effect of different loading conditions are still unclear. Systematic studies have been conducted on flax/PLA biocomposites, to determine the phenomena dominating their mechanical behaviour and their potential use in structural automotive applications

    A Guide for Gender Integration in Seed Companies : Legume Seed Value Chains of Tanzania

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    Gender inequality along a seed value chain impedes service delivery, ultimately holding back economic and social upliftment of rural communities. ‘A Guide for GENDER INTEGRATION IN SEED COMPANIES: Legume Seed Value Chains of Tanzania’ is aimed at seed companies in Tanzania that want to see greater gender integration in their businesses. This guide suggests gender-responsive actions that can be adapted by different companies based on their individual needs and context, in order to enhance their efficiencies. Seed companies can use this brief as a ‘tool’ to initiate and encourage discussions and actions that lead to more gender-inclusive value chains, improve results and lead to gains for the company, its women employees and the society in general

    Cloning, expression and functional activity of deoxyhypusine synthase from Plasmodium vivax

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    BACKGROUND: Plasmodium vivax is the most widespread human malaria parasite. However, genetic information about its pathogenesis is limited at present, due to the lack of a reproducible in vitro cultivation method. Sequencing of the Plasmodium vivax genome suggested the presence of a homolog of deoxyhypusine synthase (DHS) from P. falciparum, the key regulatory enzyme in the first committed step of hypusine biosynthesis. DHS is involved in cell proliferation, and thus a valuable drug target for the human malaria parasite P. falciparum. A comparison of the enzymatic properties of the DHS enzymes between the benign and severe Plasmodium species should contribute to our understanding of the differences in pathogenicity and phylogeny of both malaria parasites. RESULTS: We describe the cloning of a 1368 bp putative deoxyhypusine synthase gene (dhs) sequence from genomic DNA of P. vivax PEST strain Salvador I (Accession number AJ549098) after touchdown PCR. The corresponding protein was expressed and functionally characterized as deoxyhypusine synthase by determination of its specific activity and cross-reactivity to human DHS on a Western blot. The putative DHS protein from P. vivax displays a FASTA score of 75 relative to DHS from rodent malaria parasite, P. yoelii, and 74 relative to that from the human parasite, P. falciparum strain 3D7. The ORF encoding 456 amino acids was expressed under control of IPTG-inducible T7 promoter, and expressed as a protein of approximately 50 kDa (theoretically 52.7 kDa) in E. coli BL21 DE3 cells. The N-terminal histidine-tagged protein was purified by Nickel-chelate affinity chromatography under denaturing conditions. DHS with a theoretical pI of 6.0 was present in both eluate fractions. The specific enzymatic activity of DHS was determined as 1268 U/mg protein. The inhibitor, N-guanyl-1, 7-diaminoheptane (GC7), suppressed specific activity by 36-fold. Western blot analysis performed with a polyclonal anti-human DHS antibody revealed cross-reactivity to DHS from P. vivax, despite an amino acid identity of 44% between the proteins. CONCLUSION: We identify a novel DHS protein in the more benign malaria parasite,P. vivax, on the basis of specific enzymatic activity, cross-reactivity with a polyclonal antibody against human DHS, and amino acid identity with DHS homologs from the rodent malaria parasite, P. yoelii, and human P. falciparum strains

    Factors influencing cervical cancer screening in a Kenyan Health Facility: a mixed qualitative and quantitative study

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    Background: Cervical cancer is the commonest cause of cancer-related morbidity and mortality among women in developing countries in sub-Saharan Africa. Screening for cervical cancer among HIV infected women is crucial as they are more at risk of developing the disease and progressing faster once infected with Human Papilloma Virus (HPV).Methods: We aimed to determine the factors affecting the utilization of cervical cancer screening among HIV infected women above 18 years of age at Kenyatta National Hospital by conducting a cross-sectional mixed quantitative and qualitative methods study. Descriptive and inferential analysis was carried out on quantitative data to determine significant associations with cervical cancer utilization. Qualitative data were analyzed after coding for significant clauses and transcribing to determine themes arising.Results: Three hundred and twenty eight of the total 387 women enrolled reported they had been advised by their health providers to go for screening. However, only 179 (46%) reported cervical cancer screening.  Women were more likely to report cervical cancer screening if recommendation by a staff was made (p <0.001), and prior to joining KNH CCC (p <0.001). Qualitatively the main barrier to screening included fear of screening due to concerns about excessive pain or bleeding, lack of proper communication on screening procedures and long waiting timeConclusions: The utilization of cervical cancer screening services was low despite high rates of health care recommendation. The women were more likely to utilize the service if recommendation from the health care worker was made, and if they had ever screened before

    What unleashes innovations in the Legumes and Cereals farming Systems in the drylands: A gendered perspective

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    Agricultural and natural resource management innovations have often been introduced, promoted and adopted among local communities / farmers. However, how the innovation process is perceived by men and women, the relationships involved, the distribution of benefits and the differing capacities of women and men to take advantage of the new opportunities in agriculture are not always carefully thought-out. This study examined both community and individual men and women's experiences with agricultural innovations and practices and how these interactions support or hinder the achievement of agricultural innovations across various contexts. By providing robust empirical evidence on the relationship between gender norms, agency and agricultural innovation, the study revealed that sociocultural structures and household dynamics chiefly shapes how individuals negotiate for space, freedom, resources and the capacities needed to innovate

    Environmental Particle Emissions due to Automated Drilling of Polypropylene Composites and Nanocomposites Reinforced with Talc, Montmorillonite and Wollastonite

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    In this study, the effect on nanoparticle emissions due to drilling on Polypropylene (PP) reinforced with 20% talc, 5% montmorillonite (MMT) and 5% Wollastonite (WO) is investigated. The study is the first to explore the nanoparticle release from WO and talc reinforced composites and compares the results to previously researched MMT. With 5% WO, equivalent tensile properties with a 10 % weight reduction were obtained relative to the reference 20% talc sample. The materials were fabricated through injection moulding. The nanorelease studies were undertaken using the controlled drilling methodology for nanoparticle exposure assessment developed within the European Commission funded SIRENA Life 11 ENV/ES/506 project. Measurements were taken using CPC and DMS50 equipment for real-time characterization and measurements. The particle number concentration (of particles <1000nm) and particle size distribution (4.87nm - 562.34nm) of the particles emitted during drilling were evaluated to investigate the effect of the silicate fillers on the particles released. The nano-filled samples exhibited a 33% decrease (MMT sample) or a 30% increase (WO sample) on the average particle number concentration released in comparison to the neat polypropylene sample. The size distribution data displayed a substantial percentage of the particles released from the PP, PP/WO and PP/MMT samples to be between 5-20nm, whereas the PP/talc sample emitted larger particle diameters.The work is funded by and part of the European Commission Life project named Simulation of the release of nanomaterials from consumer products for environmental exposure assessment (SIRENA, Pr. No. LIFE 11 ENV/ES/596). The access and use of the facilities at the Flemish Institute for Technological Research (VITO) was funded by QualityNano Project through Transnational Access (TA Application VITO-TAF-382 and VITO-TAF-500) under the European Commission, Grant Agreement No: INFRA-2010-262163. Kristof is also thankful for partial funding by the School of Engineering at Robert Gordon University for his studentship

    Beyond a unitary household measure: Does Gender matter in Legume Seed Systems among Smallholder Farmers?

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    We employ a non-unitary household model to analyze the main Pigeonpea seed channels for in Kenya. The paper is based on a household survey conducted on a 500 randomly selected households within three counties of Eastern Kenya. The study sites are based on the distance from the main trading center (county headquarters) which informs agro business infrastructure. We assess the participation in seed channels with regards to joint plots, women plots and male plots for Pigeonpeas legumes. More than half of the Pigeonpea plots (>50 %) in the sample are managed jointly by men and women; while around 10% are managed entirely by women. There were very few plots (<1%) managed by men alone. The main legumes seed sources are own saved seeds and cereal stockists. There is very limited sourcing from the certified seed channel (<10%), the certified seeds from agrovets are only acquired for joint plots. Using a multinomial logistic regression, we analyze the factors influencing the choice of Pigeonpea seed channels, encompassing characteristics of the wife of the household head. Literate wives and wives with high exposure to extension services were more likely to access seed from the agrovets, these variables were however not significant for the male head. Other significant determinants were total livestock unit, distance to the source of seed, amount of seed required, location of the household, and occupation. We conclude that targeting women farmers with knowledge and capacity building on the advantages of using certified seeds for legumes has the potential to enhance adoption of legumes in Eastern Kenya, education levels notwithstanding

    Treatment of shigella infections: why sulfamethoxazole-trimethoprim, tetracyclines and ampicillin should no longer be used

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    Background: Bloody diarrhoea results in high morbidity and mortality especially in developing countries with shigellosis being the main cause of acute bloody diarrhoea. The use of appropriate antimicrobial agents in the treatment of acute diarrheal disease shortens the duration of illness and bacterial shedding leading to a reduction in morbidity and mortality. Treatment options for many infections are becoming limited due to globally emerging antibiotic resistance. Globally, resistance of shigella species to trimethoprim-sulfamethoxazole (TMP-SMX), tetracyclines and ampicillin has been reported with subsequent recommendations of not using these antimicrobial drugs for empirical therapy of acute bloody diarrhoea.Objective: To establish the antimicrobial susceptibility patterns and antimicrobial drug use for treatment of shigella species in patients with acute bloody diarrhoea.Design: A hospital based case control study.Setting: Six health facilities, three in Kilifi County and three in Nairobi County.Subject: A total of 284 stool specimens were collected from patients who fitted the standard cases definition for acute bloody diarrhoea.Results: Eighty (28.2%) bacterial isolates were recovered from 284 stool samples collected from cases presenting with acute bloody diarrhoea of which 67 (83.8%) were Shigella species, nine (11.3%) were Enteroinvassive Escherichia coli isolates, three (3.8%) were Salmonella Typhi and one (1.3%) were Yersinia enterocolitica. Shigella isolates had high resistance to sulfamethoxazole-trimethoprim (97%), tetracycline (83.6%) ampicillin (58.2%) and chloramphenicol (20.9%). The isolates showed low resistance to nalidixic (4.5%) and ciprofloxacin (3.0%) while there was no resistance to ceftriaxone. The most common multidrug resistance pattern detected in Shigella strains combined sulfamethoxazole-trimethoprim, amoxicillin/ampicillin and tetracyclines.Antibiotic prescriptions were given to 243(85.6%) of the patients presenting with acute bloody diarrhoea. Among these, 94 (38.7%) were given prescriptions for ciprofloxacin, 53 (21.8%) for sulfamethaxazole-trimethiprin and 36(14.8%) for Tetracyclines. Chloramphenicol, amoxicillin/ampicillin, nalidixic acid and ceftriaxone were prescribed to 10.7 %, 3.7%, 2.9% and 0.4% of the patients respectively. A total of 123 (51%) received antibiotics which were ranked to have high resistance (sulfamethoxazole-trimethoprim, tetracyclines ampicillin and chloramphenicol).Conclusion: The high rates of antimicrobial resistance among the commonly prescribed antimicrobials such as sulfamethoxazole-trimethoprim, tetracycline, ampicillin and chloramphenicol is of major concern. Despite recommendations discouraging the empirical use of sulfamethoxazole-trimethoprim, tetracycline, ampicillin and chloramphenicol for treatment of acute bloody diarrhoea, more than half of the patients with acute bloody diarrhoea were still treated with these antibiotics.There is need to train health care workers on the proper management of acute bloody diarrhoea and the importance of adhering to the clinical guidelines

    Tannin-based flax fibre reinforced composites for structural applications in vehicles.

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    Innovation is often driven by changes in government policies regulating the industries, especially true in case of the automotive. Except weight savings, the strict EU regulation of 95% recyclable material-made vehicles drives the manufactures and scientists to seek new 'green materials' for structural applications. With handing at two major drawbacks (production cost and safety), ECHOSHELL is supported by EU to develop and optimise structural solutions for superlight electric vehicles by using bio-composites made of high-performance natural fibres and resins, providing enhanced strength and bio-degradability characteristics. Flax reinforced tannin-based composite is selected as one of the candidates and were firstly investigated with different fabric lay-up angles (non-woven flax mat, UD, [0, 90°]4 and [0, +45°, 90°, −45°]2) through authors' work. Some of the obtained results, such as tensile properties and SEM micrographs were shown in this conference paper. The UD flax reinforced composite exhibits the best tensile performance, with tensile strength and modulus of 150 MPa and 9.6 MPa, respectively. It was observed that during tension the oriented-fabric composites showed some delamination process, which are expected to be eliminated through surface treatment (alkali treatment etc.) and nanotechnology, such as the use of nano-fibrils. Failure mechanism of the tested samples were identified through SEM results, indicating that the combination of fibre pull-out, fibre breakage and brittle resins failure mainly contribute to the fracture failure of composites
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