4,852 research outputs found
An Examination of the Structure of Sustainable Facilities Planning Scale for User Satisfaction in Nigerian Universities
Universities are under increasing pressure to demonstrate that continuous performance improvement is being delivered for user satisfaction, but the importance of facilities planning as a student-staff focused tool needs to be emphasised. This research sought answers to questions relating to the underlying structure of sustainable facilities planning and user satisfaction, and the number of factors that make up the facilities planning scale. Three universities from the south-western part of Nigeria were selected randomly using ownership structure to define the cases: University of Lagos, Akoka, Lagos, Ladoke Akintola University of Technology, Ogbomoso and Joseph Ayo Babalola University, Ikeji Arakeji, each representing the Federal, State, and Private ownership. A questionnaire survey was used on a random sample of 651 staff and students from the three universities. Six hundred questionnaires were retrieved (response rate of 92.2%). An exploratory factor analysis was used to understand the responses and the interrelationships. The results showed a two-factor solution of ‘locational advantages and user needs’ and ‘adequacy of facilities/functional connection and four core determinants for acceptance. It is concluded that universities should factor student-staff focus points into their facilities planning schemes to optimise their service deliveries. The study contributes to the discussion on factor structure of sustainable facilities planning scale with a focus on students and staff of universities. Keywords: Facilities planning, universities, data structure, factors, Nigeria
Hexane Extracts of Calophyllum brasiliense Inhibit the Development of Gastric Preneoplasia in Helicobacter felis Infected INS-Gas Mice
Objectives: Indigenous Latin American populations have used extracts from Calophyllum brasiliense, a native hardwood, to treat gastrointestinal symptoms for generations. The hexane extract of Calophyllum brasiliense stem bark (HECb) protects against ethanol-mediated gastric ulceration in Swiss–Webster mice. We investigated whether HECb inhibits the development of gastric epithelial pathology following Helicobacter felis infection of INS-Gas mice. Materials and Methods: Groups of five male, 6-week-old INS-Gas mice were colonized with H. felis by gavage. From 2 weeks after colonization their drinking water was supplemented with 2% Tween20 (vehicle), low dose HECb (33 mg/L, lHECb) or high dose HECb (133 mg/L, hHECb). Equivalent uninfected groups were studied. Animals were culled 6 weeks after H. felis colonization. Preneoplastic pathology was quantified using established histological criteria. Gastric epithelial cell turnover was quantified by immunohistochemistry for Ki67 and active-caspase 3. Cytokines were quantified using an electrochemiluminescence assay. Results: Vehicle-treated H. felis infected mice exhibited higher gastric atrophy scores than similarly treated uninfected mice (mean atrophy score 5.6 ± 0.87 SEM vs. 2.2 ± 0.58, p < 0.01). The same pattern was observed following lHECb. Following hHECb treatment, H. felis status did not significantly alter atrophy scores. Gastric epithelial apoptosis was not altered by H. felis or HECb administration. Amongst vehicle-treated mice, gastric epithelial cell proliferation was increased 2.8-fold in infected compared to uninfected animals (p < 0.01). Administration of either lHECb or hHECb reduced proliferation in infected mice to levels similar to uninfected mice. A Th17 polarized response to H. felis infection was observed in all infected groups. hHECb attenuated IFN-γ, IL-6, and TNF production following H. felis infection [70% (p < 0.01), 67% (p < 0.01), and 41% (p < 0.05) reduction vs. vehicle, respectively]. Conclusion: HECb modulates gastric epithelial pathology following H. felis infection of INS-Gas mice. Further studies are indicated to confirm the mechanisms underlying these observations
Isolation, identification and diesel-oil biodegradation capacities of indigenous hydrocarbon-degrading strains of Cellulosimicrobium cellulans and Acinetobacter baumannii from tarball at Terengganu beach, Malaysia
In this study, we isolated two indigenous hydrocarbon-degrading bacteria from tarball found in Rhu Sepuluh beach, Terengganu, Malaysia. These bacteria were identified based on their physiological characteristic and 16S rRNA gene sequence analysis, and they showed 99% similarity with Cellulosimicrobium cellulans DSM 43879 and Acinetobacter baumannii ATCC 19606 respectively. Their hydrocarbon-degrading capabilities were tested using diesel-oil as sole carbon source. Results analysed using GC–MS, showed diesel-oil alkanes were degraded an average 64.4% by C. cellulans and 58.1% by A. baumannii with medium optical density reaching 0.967 (C. cellulans) and 1.515 (A. baumannii) in minimal salt media at 32 °C for 10 days. Individual diesel-oil alkanes were degraded between 10%–95.4% by C. cellulans and 0.2%–95.9% by A. baumannii. Both strains utilized diesel-oil for growth. The study suggests both strains are part of indigenous hydrocarbon-degrading bacteria in tarball with potential for bioremediation of oil-polluted marine environment
Isolation, molecular identification and biodegradation capacities of indigenous hydrocarbon-degrading bacteria from tarball at Terengganu beach, Malaysia
In this study, we isolated four indigenous hydrocarbon-degrading bacteria from tarball found in Rhu Sepuluh beach, Terengganu, Malaysia. These bacteria were identified based on their physiological characteristic and 16S rRNA gene sequence analysis, and they showed 99% similarity with Pseudomonas stutzeri strain A1501, Pseudomonas balearica strain SP1402, Cellulosimicrobium cellulans DSM 43879 and Acinetobacter baumannii ATCC 19606 respectively. Their hydrocarbon-degrading capabilities were tested using diesel-oil as sole carbon source. Results analysed using GC-MS, showed diesel-oil alkanes were degraded an average 30.5%, 16.4%, 64.4% and 58.1% with medium optical density reaching 1.172, 1.503, 0.967 and 1.515 by Pseudomonas stutzeri, Pseudomonas balearica, Cellulosimicrobium cellulans and Acinetobacter baumannii respectively in minimal salt media at 32oC for 10 days. Individual diesel-oil alkanes were degraded between 19.7% - 49.2% (P. stutzeri), 2.5% to 27.5% (P. balearica), 10% - 95.4% (C. cellulans) and 0.2% - 95.9% (A. baumannii). All strains utilized diesel-oil for growth. The study suggests all strains are part of indigenous hydrocarbon-degrading bacteria in tarball with potential for bioremediation of oil-polluted marine environment
Isolation and optimization of diesel-oil biodegradation using Cellulosimicrobium cellulans from tarball
Oil spill introduces hydrocarbons into the marine environment and forms oil slicks, which aggregate with other debris to form tarballs. Tarballs are composed of toxic hydrocarbons, which persist in the environment, causing economic and ecological damages. This work studied the isolation and optimization of diesel-oil biodegradation by an indigenous bacterium, identified by 16S rRNA gene sequence analysis, in tarball. An experimental methodology using a Taguchi orthogonal array was applied to optimize the effects of diesel concentration, salinity, nitrate concentration, pH, temperature, agitation speed and time. An isolated bacterium identified as Cellulosimicrobium cellulans removed 88.4% of diesel oil under optimized conditions, where initial diesel-oil concentration was 5% (v/v), NaCl concentration was 20 gL-1 and NH4NO3 concentration was 2 gL-1 in Minimal Salt Media at pH 7, 40°C and 100 revolutions per minute for 5 days. Tarballs harbor hydrocarbon-degrading C. cellulans that can be used under optimized conditions to design an effective oil spill bioremediation technique for mitigating oil pollution
Experimental investigation of the air-fuel charging process in a four-valve supercharged two-stroke cycle GDI engine
Fuel consumption standards imposed in several countries for the next years have prompted the development of hybrid passenger cars with ever smaller internal combustion engines. In such powertrain, fuel consumption is as important as engine packaging and power density, so two-stroke engines may be an option due to their higher combustion frequency compared to four-stroke engines. Therefore, the present research investigates the air–fuel charging process of an overhead four-valve direct injection supercharged engine operating in the two-stroke cycle. The optimum start of fuel injection was evaluated for commercial gasoline by means of indicated and combustion efficiencies where a trade-off was found between early and late fuel injections. By advancing the injection timing, more fuel was prone to short circuit to the exhaust during the valve overlap, while late injections resulted in poor charge preparation. The gas exchange parameters, i.e. charging and trapping efficiencies, were obtained from seventy operating points running at fuel-rich conditions. The Benson–Brandham mixing-displacement scavenging model was then fit to the experimental data with a coefficient of determination better than 0.95. With such model, the air trapping and charging efficiencies could be estimated solely based on the scavenge ratio and exhaust lambda, regardless of the engine load, speed, or air/fuel ratio employed. Further twenty-five different lean-burn testing points were tested to certify the proposed methodology applied to the poppet valve two-stroke engine. The in-cylinder lambda was calculated and found different from the exhaust lambda due to mixing between burned gases and intake air during the scavenging process
Polycomb Repressive Complex 2 Regulates Genes Necessary for Intestinal Microfold Cell (M Cell) Development
BACKGROUND & AIMS: Microfold cells (M cells) are immunosurveillance epithelial cells located in the Peyer's patches (PPs) in the intestine and are responsible for monitoring and transcytosis of antigens, microorganisms, and pathogens. Mature M cells use the receptor glycoprotein 2 (GP2) to aid in transcytosis. Recent studies have shown transcription factors, Spi-B and SRY-Box Transcription Factor 8 (Sox8). are necessary for M-cell differentiation, but not sufficient. An exhaustive set of factors sufficient for differentiation and development of a mature GP2+ M cell remains elusive. Our aim was to understand the role of polycomb repressive complex 2 (PRC2) as an epigenetic regulator of M-cell development. Estrogen-related-receptor gamma (Esrrg), identified as a PRC2-regulated gene, was studied in depth, in addition to its relationship with Spi-B and Sox8. METHODS: Comparative chromatin immunoprecipitation and global run-on sequencing analysis of mouse intestinal organoids were performed in stem condition, enterocyte conditions, and receptor activator of nuclear factor kappa B ligand-induced M-cell condition. Esrrg, which was identified as one of the PRC2-regulated transcription factors, was studied in wild-type mice and knocked out in intestinal organoids using guide RNA's. Sox8 null mice were used to study Esrrg and its relation to Sox8. RESULTS: chromatin immunoprecipitation and global run-on sequencing analysis showed 12 novel PRC2 regulated transcription factors, PRC2-regulated Esrrg is a novel M-cell-specific transcription factor acting on a receptor activator of nuclear factor kappa B ligand-receptor activator of nuclear factor kappa B-induced nuclear factor-kappa B pathway, upstream of Sox8, and necessary but not sufficient for a mature M-cell marker of Gp2 expression. CONCLUSIONS: PRC2 regulates a significant set of genes in M cells including Esrrg, which is critical for M-cell development and differentiation. Loss of Esrrg led to an immature M-cell phenotype lacking in Sox8 and Gp2 expression. Transcript profiling: the data have been deposited in the NCBI Gene Expression Omnibus database (GSE157629).Peer reviewe
In vitro mycorrhization of micropropagated plants: studies on Castanea sativa Mill.
In vitro mycorrhization can be made by several axenic and nonaxenic
techniques but criticism exists about their artificiality and inability to
reproduce under natural conditions. However, artificial mycorrhization under
controlled conditions can provide important information about the physiology
of symbiosis. Micropropagated Castanea sativa plants were inoculated with
the mycorrhizal fungus Pisolithus tinctorius after in vitro rooting. The
mycorrhizal process was monitored at regular intervals in order to evaluate the
mantle and hartig net formation, and the growth rates of mycorrhizal and
nonmycorrhizal plants. Plant roots show fungal hyphae adhesion at the surface
after 24 hours of mycorrhizal induction. After 20 days a mantle can be
observed and a hartig net is forming although the morphology of the epidermal
cells remains unaltered. At 30 days of root–fungus contact the hartig net is
well developed and the epidermal cells are already enlarged. After 50 days of
mycorrhizal induction, growth was higher for mycorrhizal plants than for
nonmycorrhizal ones. The length of the major roots was lower in mycorrhizal
plants after 40 days. Fresh and dry weights were higher in mycorrhizal plants
after 30 days. The growth rates of chestnut mycorrhizal plants are in agreement
with the morphological development of the mycorrhizal structures observed at
each mycorrhizal time. The assessment of symbiotic establishment takes into
account the formation of a mantle and a hartig net that were already developed
at 30 days, when differences between fresh and dry weights of mycorrhizal and
nonmycorrhizal plants can be quantified. In vitro conditions, mycorrhization
influences plant physiology after 20 days of root–fungus contact, namely in
terms of growth rates. Fresh and dry weights, heights, stem diameter and
growth rates increased while major root growth rate decreased in mycorrhizal
plants.Springe
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