1,000 research outputs found

    Cholesterol promotes interaction of the protein CLIC1 with phospholipid monolayers at the air–water interface

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    © 2016 by the authors; licensee MDPI, Basel, Switzerland. CLIC1 is a Chloride Intracellular Ion Channel protein that exists either in a soluble state in the cytoplasm or as a membrane bound protein. Members of the CLIC family are largely soluble proteins that possess the intriguing property of spontaneous insertion into phospholipid bilayers to form integral membrane ion channels. The regulatory role of cholesterol in the ion‐channel activity of CLIC1 in tethered lipid bilayers was previously assessed using impedance spectroscopy. Here we extend this investigation by evaluating the influence of cholesterol on the spontaneous membrane insertion of CLIC1 into Langmuir film monolayers prepared using 1‐palmitoyl‐2‐oleoylphosphatidylcholine, 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phospho‐ethanolamine and 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phospho‐L‐serine alone or in combination with cholesterol. The spontaneous membrane insertion of CLIC1 was shown to be dependent on the presence of cholesterol in the membrane. Furthermore, pre‐incubation of CLIC1 with cholesterol prior to its addition to the Langmuir film, showed no membrane insertion even in monolayers containing cholesterol, suggesting the formation of a CLIC1‐cholesterol pre‐complex. Our results therefore suggest that CLIC1 membrane interaction involves CLIC1 binding to cholesterol located in the membrane for its initial docking followed by insertion. Subsequent structural rearrangements of the protein would likely also be required along with oligomerisation to form functional ion channels

    Microleakage of composite resin restorations in cervical cavities prepared by Er,Cr: YSGG laser radiation

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    Background: Evaluation of microleakage is important for assessing the success of new methods for surface preparation and new adhesive restorative materials. The aim of this laboratory study was to assess microleakage at the margins of composite restorations in Er,Cr:YSGG laser prepared cavities on the cervical aspects of teeth by means of dye penetration, and compare this with conventionally prepared and conditioned cavities. Methods: Class V cavities were produced on sound extracted human teeth, which had been assigned randomly to one of three groups (N = 10 each), as follows: Group 1 – prepared using a diamond cylindrical bur and then treated with 37% phosphoric acid; Group 2 – irradiated with an Er,Cr:YSGG laser (Biolase Waterlase) and then treated with 37% phosphoric acid; Group 3 – irradiated only with the laser. After application of bonding agent (Excite, Ivoclar Vivadent), all cavities were restored with composite resin (Heliomolar). After polishing the restorations, the teeth were thermocycled from 5–50°C for 500 cycles. Dye leakage was assessed after immersion in methylene blue, by examining longitudinal sections in a stereomicroscope at ×30 magnification. Results: The extent of dye penetration was lowest in the laser only group (Group 3). Penetration of dye to dentine and axial walls occurred in 80 per cent of conventionally prepared (bur + acid) specimens, but in the laser group, dye penetration to the axial wall occurred in only 30 per cent of cases. There was a strong statistical association between treatment group and the distribution of microleakage scores (Chi-square, P = 0.0023). Conclusions: For Class V cavities, with the adhesive materials employed, higher microleakage occurs with phosphoric acid etching of bur- or laser-cut surfaces, than with the surface created by use of the laser alone without additional conditioning

    Obesity, Disability and Self-Perceived Health Outcomes in Australian Adults: A Longitudinal Analysis Using 14 Annual Waves of the HILDA Cohort.

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    Background: Both obesity and disability have been widely recognised as major public health challenges because they play significant roles in determining self-perceived general and mental health. Longitudinal studies of the relationship between obesity and disability with self-reported health outcomes are scarce. Therefore, the objective of the present study is to examine the relationship between obesity and disability with self-perceived general and mental health among Australian adults aged 15 years and above. Methods: Data were extracted from the most recent 14 waves (waves 6 through 19) of the annual individual person dataset of the Household, Income and Labour Dynamics in Australia (HILDA) survey. The longitudinal random-effects logistic regression model was adopted to investigate the relationships between obesity and disability with self-reported health outcomes. Results: The results revealed that obese individuals and adults with some form of disability are more likely to report poor or fair general and mental health. The odds of self-reporting poor or fair general health were 2.40 and 6.07 times higher among obese (aOR: 2.40, 95% CI: 2.22-2.58) and adults with some form of disability (aOR: 6.07, 95% CI: 5.77-6.39), respectively, relative to adults with healthy weight and those without disability . The results also showed that self-rated poor or fair mental health were 1.22 and 2.40 times higher among obese adults (aOR: 1.22, 95% CI: 1.15-1.30) and adults with disability (aOR: 2.40, 95% CI: 2.30-2.51), respectively, compared to their healthy weight peers and peers without disability. Conclusion: As governmental and non-governmental organisations seek to improve the community's physical and mental well-being, these organisations need to pay particular attention to routine health care prevention, specific interventions, and treatment practices, especially for obese and/or people with disabilities

    A systematic review of economic evaluations of health and health-related interventions in Bangladesh

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    <p>Abstract</p> <p>Background</p> <p>Economic evaluation is used for effective resource allocation in health sector. Accumulated knowledge about economic evaluation of health programs in Bangladesh is not currently available. While a number of economic evaluation studies have been performed in Bangladesh, no systematic investigation of the studies has been done to our knowledge. The aim of this current study is to systematically review the published articles in peer-reviewed journals on economic evaluation of health and health-related interventions in Bangladesh.</p> <p>Methods</p> <p>Literature searches was carried out during November-December 2008 with a combination of key words, MeSH terms and other free text terms as suitable for the purpose. A comprehensive search strategy was developed to search Medline by the PubMed interface. The first specific interest was mapping the articles considering the areas of exploration by economic evaluation and the second interest was to scrutiny the methodological quality of studies. The methodological quality of economic evaluation of all articles has been scrutinized against the checklist developed by Evers Silvia and associates.</p> <p>Result</p> <p>Of 1784 potential articles 12 were accepted for inclusion. Ten studies described the competing alternatives clearly and only two articles stated the perspective of their articles clearly. All studies included direct cost, incurred by the providers. Only one study included the cost of community donated resources and volunteer costs. Two studies calculated the incremental cost effectiveness ratio (ICER). Six of the studies applied some sort of sensitivity analysis. Two of the studies discussed financial affordability of expected implementers and four studies discussed the issue of generalizability for application in different context.</p> <p>Conclusion</p> <p>Very few economic evaluation studies in Bangladesh are found in different areas of health and health-related interventions, which does not provide a strong basis of knowledge in the area. The most frequently applied economic evaluation is cost-effectiveness analysis. The majority of the studies did not follow the scientific method of economic evaluation process, which consequently resulted into lack of robustness of the analyses. Capacity building on economic evaluation of health and health-related programs should be enhanced.</p

    Evidence of the Key Role of H<inf>3</inf>O<sup>+</sup> in Phospholipid Membrane Morphology

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    © 2016 American Chemical Society. This study explains the importance of the phosphate moiety and H3O+ in controlling the ionic flux through phospholipid membranes. We show that despite an increase in the H3O+ concentration when the pH is decreased, the level of ionic conduction through phospholipid bilayers is reduced. By modifying the lipid structure, we show the dominant determinant of membrane conduction is the hydrogen bonding between the phosphate oxygens on adjacent phospholipids. The modulation of conduction with pH is proposed to arise from the varying H3O+ concentrations altering the molecular area per lipid and modifying the geometry of conductive defects already present in the membrane. Given the geometrical constraints that control the lipid phase structure of membranes, these area changes predict that organisms evolving in environments with different pHs will select for different phospholipid chain lengths, as is found for organisms near highly acidic volcanic vents (short chains) or in highly alkaline salt lakes (long chains). The stabilizing effect of the hydration shells around phosphate groups also accounts for the prevalence of phospholipids across biology. Measurement of ion permeation through lipid bilayers was made tractable using sparsely tethered bilayer lipid membranes with swept frequency electrical impedance spectroscopy and ramped dc amperometry. Additional evidence of the effect of a change in pH on lipid packing density is obtained from neutron reflectometry data of tethered membranes containing perdeuterated lipids

    Student Performance Analysis System (SPAS)

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    Almost every university have their own management system to manage the students' records. Currently, even though there is a student management system that manages the students' records in Universiti Malaysia Sarawak (UNIMAS), no permission is provided for lecturers to access the system. This is because the access permission is only to top management such as Deans and Deputy Deans of Undergraduate and Student Development due to its privacy setting. Thus, this project proposes a system named Student performance analysis system (SPAS) to keep track of students' result in the Faculty of Computer Science and Information Technology (FCSIT). The proposed system offer a predictive system that is able to predict the students' performance in course “TMC1013 System Analysis and Design”, which in turns assists the lecturers from Information System department to identify students that are predicted to have bad performance in course “TMC1013 System Analysis and Design”. The proposed system offers student performance prediction through the rules generated via data mining technique. The data mining technique used in this project is classification, which classifies the students based on students' grade

    Epidemiology and genetic characterization of Peste des petits ruminants virus in Bangladesh

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    Peste des petits ruminants (PPR) is an acute, highly contagious disease responsible for high morbidity and mortality rates in susceptible sheep and goats. Adequate knowledge of the diversity of circulating strains of PPR virus will help livestock authorities choose appropriate vaccines. The objective of this study was to describe the epidemiology of PPR and characterize the strains circulating in Bangladesh. Veterinarians enrolled goats showing signs consistent with PPR, including diarrhoea, fever and respiratory distress, from three veterinary hospitals. Post-treatment follow up was carried out to ascertain health outcomes of the goats. Faecal and throat swab samples were collected from the goats and tested for PPRV RNA using real-time reverse transcription polymerase chain reaction (rRT-PCR). Nucleotide sequence-based phylogenetic analyses of two structural genes, the nucleocapsid (N gene), and the haemagglutinin (H gene) were studied to determine the genetic variations of PPRV strains. Of the 539 goats enrolled, 38% (203/539) had detectable RNA for PPRV. We were able to follow up with 91% (184/203) of the PPRV infected goats; 44 of them died (24%). PPRV was more frequently identified in the summer (45%) than in the rainy season (29%) (Odds ratio = 1.9, 95% confidence interval: 1.3–3.1). Bangladeshi strains were phylogenetically similar to the lineage IV PPRV strains; showing particularly strong affiliation with Tibetan and Indian strains. PPR is a common viral infection of the goats in Bangladesh, with a high case-fatality rate. This study confirms the circulation of lineage IV PPRV in the country with unique amino acid substitutions in N and H proteins and provides baseline data for vaccine development and implementation

    Radiative and magnetohydrodynamics flow of third grade viscoelastic fluid past an isothermal inverted cone in the presence of heat generation/absorption

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    A mathematical analysis is presented to investigate the nonlinear, isothermal, steady-state, free convection boundary layer flow of an incompressible third grade viscoelastic fluid past an isothermal inverted cone in the presence of magnetohydrodynamic, thermal radiation and heat generation/absorption. The transformed conservation equations for linear momentum, heat and mass are solved numerically subject to the realistic boundary conditions using the second-order accurate implicit finite-difference Keller Box Method. The numerical code is validated with previous studies. Detailed interpretation of the computations is included. The present simulations are of interest in chemical engineering systems and solvent and low-density polymer materials processing

    Alkali activation of vitreous calcium aluminosilicate derived from glass fiber waste

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    The properties and microstructure of alkali-activated (AA) vitreous calcium aluminosilicate (VCAS) are presented in this paper. VCAS is manufactured from a by-product of the glass fiber industry and has been activated using NaOH and KOH solutions. The microstructure and mechanical properties of AA VCAS pastes and mortars are reported. The results show that depending on the type and concentration of hydroxide solution used, mortar samples with compressive strengths up to 77 MPa can be formed after curing for three days at 65 °C. The research demonstrates the potential of VCAS to produce AA cements and the importance of alkali type and concentration in optimizing properties and microstructure.Mitsuuchi Tashima, M.; Soriano Martinez, L.; Borrachero Rosado, MV.; MonzĂł Balbuena, JM.; Cheeseman, CR.; Paya Bernabeu, JJ. (2012). Alkali activation of vitreous calcium aluminosilicate derived from glass fiber waste. 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Effect of curing time on the microstructure and mechanical strength development of alkali activated nbinders based on vitreous calcium aluminosilicate (VCAS). Bull. Mater. Sci. in press.Hemmings RT, Nelson RD, Graves PL, Cornelius BJ. White pozzolan composition and blended cements containing same. Patent US6776838. 2004.Provis, J. L., Lukey, G. C., & van Deventer, J. S. J. (2005). Do Geopolymers Actually Contain Nanocrystalline Zeolites? A Reexamination of Existing Results. Chemistry of Materials, 17(12), 3075-3085. doi:10.1021/cm050230iCriado, M., FernĂĄndez-JimĂ©nez, A., de la Torre, A. G., Aranda, M. A. G., & Palomo, A. (2007). An XRD study of the effect of the SiO2/Na2O ratio on the alkali activation of fly ash. Cement and Concrete Research, 37(5), 671-679. doi:10.1016/j.cemconres.2007.01.013Rees, C. A., Provis, J. L., Lukey, G. C., & van Deventer, J. S. J. (2007). In Situ ATR-FTIR Study of the Early Stages of Fly Ash Geopolymer Gel Formation. 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R., BĂŒcker, M., Bossert, J., & Marszalek, K. (1997). Glass matrix composites from coal flyash and waste glass. Waste Management, 17(1), 39-45. doi:10.1016/s0956-053x(97)00035-4Kourti, I., Rani, D. A., Deegan, D., Boccaccini, A. R., & Cheeseman, C. R. (2010). Production of geopolymers using glass produced from DC plasma treatment of air pollution control (APC) residues. Journal of Hazardous Materials, 176(1-3), 704-709. doi:10.1016/j.jhazmat.2009.11.089Lampris, C., Lupo, R., & Cheeseman, C. R. (2009). Geopolymerisation of silt generated from construction and demolition waste washing plants. Waste Management, 29(1), 368-373. doi:10.1016/j.wasman.2008.04.007Wu, H.-C., & Sun, P. (2007). New building materials from fly ash-based lightweight inorganic polymer. Construction and Building Materials, 21(1), 211-217. doi:10.1016/j.conbuildmat.2005.06.052Kourti, I., Amutha Rani, D., Boccaccini, A. R., & Cheeseman, C. R. (2011). Geopolymers from DC Plasma–Treated Air Pollution Control Residues, Metakaolin, and Granulated Blast Furnace Slag. Journal of Materials in Civil Engineering, 23(6), 735-740. doi:10.1061/(asce)mt.1943-5533.000017
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