83 research outputs found

    In vitro multiplication of Pogostemon cablin Benth. through direct regeneration

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    An efficient method was developed to initiate multiple shoots from nodal explants of Pogostemon cablin Benth. MS medium supplemented with 0.5 mg/L BA initiated a mean of 45.66 shoots/nodal explant. Within 4 weeks of initiation, regenerated multiple shoots attained a height of 3.6 cm. Subsequent transfer of these in vitro derived nodal segments onto MS medium supplemented with BA and KN ( 0.5 mg/L), induced mean of 62.45 shoots. Higher concentration of either BA or KN more than 0.5 mg/L resulted in callus proliferation and showed hyperhydric shoots with morphological abnormalities. Rooting was readily achieved upon transfer of shoots on half strength MS medium supplemented with 100mg/L activated charcoal. Rooted shoots, following acclimatization in green house, were successfully transferred to soil with 91% survival. Also shoots regenerated in vitro were directly transplanted to soil and acclimatized. Tissue cultured plants were analyzed for oil content by employing gas chromatography and found that the patterns were similar to mother plants

    Fabrication, Mechanical and Wear Properties of Aluminum (Al6061)-Silicon Carbide-Graphite Hybrid Metal Matrix Composites

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    In recent times, the use of aluminum alloy-based Hybrid Metal Matrix Composites (HMMCs) is being increased in aerospace and automotive applications. HMMCs compensate for the low desirable properties of each filler used. However, the mechanical properties of HMMCs are not well understood. In particular, microstructural investigations and wear optimization studies of HMMCs are not clear. Therefore, further studies are required. The present study is aimed at fabricating and mechanical and wear characterizing and microstructure investigating of Silicon Carbide (SiC) and Graphite (Gr) added in Aluminum (Al) alloy Al6061 HMMCs. The addition of SiC particles was in the range from 0 to 9 weight percentage (wt.%) in steps of 3, along with the addition of 1 wt.% Gr in powder form. The presence of alloying elements in the Al6061 alloy was identified using the Energy Dispersive X-Ray Analysis (EDX). The dispersion of SiC and Gr particles in the alloy was investigated using metallurgical microscope and Scanning Electron Microscopy (SEM). The gain in strength can be attributed to the growth in dislocation density. The nature of fracture was quasi-cleavage. The microstructure examination reveals the uniform dispersion of the reinforcement. Density, hardness, and Ultimate Tensile Strength values observed to be increased with increased contents of SiC reinforcement. Besides, wear studies were performed in dry sliding conditions. Optimization studies were performed to investigate the effect of parameters that affecting the wear. The sliding wear resistance was noticed to be improved concerning higher amounts of reinforcement leading to a decrease in delamination and adhesive wear. The predicted values for the wear rate have also been compared with the experimental results and good correlation is obtained

    Asp-89: a critical residue in maintaining the oligomeric structure of sheep liver cytosolic serine hydroxymethyltransferase

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    Aspartate residues function as proton acceptors in catalysis and are involved in ionic interactions stabilizing subunit assembly. In an attempt to unravel the role of a conserved aspartate (D89) in sheep-liver tetrameric serine hydroxymethyltransferase (SHMT), it was converted into aspargine by site-directed mutagenesis. The purified D89N mutant enzyme had a lower specific activity compared with the wild-type enzyme. It was a mixture of dimers and tetramers with the proportion of tetramers increasing with an increase in the pyridoxal-5′-phosphate (PLP) concentration used during purification. The D89N mutant tetramer was as active as the wild-type enzyme and had similar kinetic and spectral properties in the presence of 500 μM PLP. The quinonoid spectral intermediate commonly seen in the case of SHMT was also seen in the case of D89N mutant tetramer, although the amount of intermediate formed was lower. Although the purified dimer exhibited visible absorbance at 425 nm, it had a negligible visible CD spectrum at 425 nm and was only 5% active. The apo-D89N mutant tetramer was a dimer unlike the apo-form of the wild-type enzyme which was present predominantly as a tetramer. Furthermore the apo mutant dimer could not be reconstituted to the holo-form by the addition of excess PLP, suggesting that dimer-dimer interactions are weak in this mutant. The recently published crystal structure of human liver cytosolic recombinant SHMT indicates that this residue (D90 in the human enzyme) is located at the N-terminal end of the fourth helix of one subunit and packs against K39 from the second N-terminal helix of the other symmetry related subunit forming the tight dimer. D89 is at the interface of tight dimers where the PLP 5'-phosphate is also bound. Mutation of D89 could lead to weakened ionic interactions in the tight dimer interface, resulting in decreased affinity of the enzyme for the cofactor

    VeSV- Value at the end of the Sanitation Value Chain: Final Report

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    Bangladesh is no stranger to composting projects using both green waste and faecal sludge (FS). There have been many initiatives over the years with varying degrees of success. Similarly there have been hundreds, if not thousands of projects to improve access to latrines, latrine use and latrine management. Again there has been a great deal of success, especially in increasing the number of latrines being built. However, a key gap regarding the safe collection and processing of the waste from the pit still remains. In cases where projects have attempted addressing this, the solution has rarely been viable on a large scale. That is where this project—VeSV—is different. The aim of this project is to provide scientific evidence to support the commercial viability of collecting and composting faecal sludge for use in agriculture and horticulture. The gap between a good idea and commercial success is bridged on this project by producing primary scientific data based on qualitative and quantitative research methods and by engaging a number of stakeholders across sectors. A rigorous research was conducted to characterize raw faecal sludge material from single pit latrines in rural Bangladesh, as the starting point to develop value across the sanitation chain from processing FS material, through adding value by recovering nutrient and finally by assessing the potential commercialization of the final product in the fertilizer market. Crucially academics, NGOs, business groups and existing fertilizer, composting and latrine management companies were involved as part of our Reference Group, which helped to develop practical engineering solutions in harmony with the right and relevant context in rural Bangladesh. Our research outcomes include the development of safe methodologies for pit emptying; the assessment of people's intentions to change current operation and maintenance practices of pit latrines at household level and their willingness to participate in commercially viable and sustainable methods for FS management; the assessment of optimised engineering process for FS stabilisation and the production of a safe, high quality fertilizer that is desirable to farmers; and the identification of potential hurdles that may obstruct the widespread adoption of business models for FS fertiliser

    Towards sustainable sanitation management: Establishing the costs and willingness to pay for emptying and transporting sludge in rural districts with high rates of access to latrines

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    MOTIVATION: Proper management of fecal sludge has significant positive health and environmental externalities. Most research on managing onsite sanitation so far either simulates the costs of, or the welfare effects from, managing sludge in situ in pit latrines. Thus, designing management strategies for onsite rural sanitation is challenging, because the actual costs of transporting sludge for treatment, and sources for financing these transport costs, are not well understood. METHODS: In this paper we calculate the actual cost of sludge management from onsite latrines, and identify the contributions that latrine owners are willing to make to finance the costs. A spreadsheet-based model is used to identify a cost-effective transport option, and to calculate the cost per household. Then a double-bound contingent valuation method is used to elicit from pit-latrine owners their willingness-to-pay to have sludge transported away. This methodology is employed for the case of a rural subdistrict in Bangladesh called Bhaluka, a unit of administration at which sludge management services are being piloted by the Government of Bangladesh. RESULTS: The typical sludge accumulation rate in Bhaluka is calculated at 0.11 liters/person/day and a typical latrine will need to be emptied approximately once every 3 to 4 years. The costs of emptying and transport are high; approximately USD 13 per emptying event (circa 14% of average monthly income); household contributions could cover around 47% of this cost. However, if costs were spread over time, the service would cost USD 4 per year per household, or USD 0.31 per month per household-comparable to current expenditures of rural households on telecommunications. CONCLUSION: This is one of few research papers that brings the costs of waste management together with financing of that cost, to provide evidence for an implementable solution. This framework can be used to identify cost effective sludge management options and private contributions towards that cost in other (context-specific) administrative areas where onsite sanitation is widespread

    Incisional hernia following colorectal cancer surgery according to suture technique: Hughes Abdominal Repair Randomized Trial (HART).

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    BACKGROUND: Incisional hernias cause morbidity and may require further surgery. HART (Hughes Abdominal Repair Trial) assessed the effect of an alternative suture method on the incidence of incisional hernia following colorectal cancer surgery. METHODS: A pragmatic multicentre single-blind RCT allocated patients undergoing midline incision for colorectal cancer to either Hughes closure (double far-near-near-far sutures of 1 nylon suture at 2-cm intervals along the fascia combined with conventional mass closure) or the surgeon's standard closure. The primary outcome was the incidence of incisional hernia at 1 year assessed by clinical examination. An intention-to-treat analysis was performed. RESULTS: Between August 2014 and February 2018, 802 patients were randomized to either Hughes closure (401) or the standard mass closure group (401). At 1 year after surgery, 672 patients (83.7 per cent) were included in the primary outcome analysis; 50 of 339 patients (14.8 per cent) in the Hughes group and 57 of 333 (17.1 per cent) in the standard closure group had incisional hernia (OR 0.84, 95 per cent c.i. 0.55 to 1.27; P = 0.402). At 2 years, 78 patients (28.7 per cent) in the Hughes repair group and 84 (31.8 per cent) in the standard closure group had incisional hernia (OR 0.86, 0.59 to 1.25; P = 0.429). Adverse events were similar in the two groups, apart from the rate of surgical-site infection, which was higher in the Hughes group (13.2 versus 7.7 per cent; OR 1.82, 1.14 to 2.91; P = 0.011). CONCLUSION: The incidence of incisional hernia after colorectal cancer surgery is high. There was no statistical difference in incidence between Hughes closure and mass closure at 1 or 2 years. REGISTRATION NUMBER: ISRCTN25616490 (http://www.controlled-trials.com)
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