Response of precast foamed concrete sandwich panels to flexural loading

This paper presents the results of an experimental and analytical investigation of a total of six precast foamed concrete sandwich panels (PFCSPs) as one-way acting slabs tested under flexural loads. Foamed concrete of 25.73 MPa was used to produce the PFCSP concrete wythes. The results obtained from the tests have been discussed in terms of ultimate flexural strength capacity, moment-vertical deflection profile, load–strain relationship, strain variation across the slab depth, influence of aspect ratio, cracking patterns, and ultimate flexural load at failure. An analytical study of finite element analysis (FEA) as a one-way slab model was then conducted. The increase in aspect ratio (L/d) from 18.33 to 26.67 shows a reduction of 50% and 69.6% on the ultimate flexural strength capacity as obtained experimentally and in FEA models, respectively. Theoretical analyses on the extremes of fully composite and non-composite actions were also determined. The experimental results showed that cracking patterns were observed in one direction only, similar to those reported on a reinforced concrete solid slab, as well as precast concrete sandwich panels, when both concrete wythes act in a single composite manner. The experimental results were compared with FEA model data, and a significant degree of accuracy was obtained. Therefore, the PFCSP slab can serve as an alternative to the normal concrete slab system in buildings

Nutritional and socio-economic determinants of cognitive function and educational achievement of Aboriginal schoolchildren in rural Malaysia

A community-based cross-sectional study was carried out among Aboriginal schoolchildren aged 7-12 years living in remote areas in Pos Betau, Pahang, Malaysia to investigate the potential determinants influencing the cognitive function and educational achievement of these children. Cognitive function was measured by intelligence quotient (IQ), while examination scores of selected school subjects were used in assessing educational achievement. Blood samples were collected to assess serum Fe status. All children were screened for soil-transmitted helminthes. Demographic and socio-economic data were collected using pre-tested questionnaires. Almost two-thirds (67.6 ) of the subjects had poor IQ and most of them (72.6) had insufficient educational achievement. Output of the stepwise multiple regression model showed that poor IQ was significantly associated with low household income which contributed the most to the regression variance (r(2) 0.059; P=0.020). Low maternal education was also identified as a significant predictor of low IQ scores (r(2) 0.042; P=0.043). With educational achievement, Fe-deficiency anaemia (IDA) was the only variable to show significant association (r(2) 0.025; P=0.015). In conclusion, the cognitive function and educational achievement of Aboriginal schoolchildren are poor and influenced by household income, maternal education and IDA. Thus, effective and integrated measures to improve the nutritional and socio-economic status of rural children would have a pronounced positive effect on their education

Friction performance analysis of waste tire rubber powder reinforced polypropylene using pin-on-disk tribometer

Waste tire rubber powder reinforced polypropylene composites were established with different set of compositions ranging from 0% to 40%, where coefficient of friction for each of them was analyzed by pin on disk tribometer. The tribological effect between the pin-disk reveals of how the reinforcement plays a vital role in enhancing the coefficient of friction as compared to virgin polypropylene. This paper also elaborates in detail of how the matrix, reinforcement, specimen and test were prepared and conducted via critically designed methodology. A specially designed non-metallic parted line mold was used to ease specimen removal. SEM micrographs provides clearer view of what actually happens between the inter layer bonding of matrix and reinforced materials. The promising findings not only save the environment by utilizing waste tires which are often difficult to be disposed, but it also significantly enhanced the coefficient of friction for pure polypropylene which is highly potential to be used in engineering applications. The correlation between these materials was found towards routing an alternative way of how waste tires could be utilized to engineer new composite materials

Evaluation of the use of Cocos nucifera as antimalarial remedy in Malaysian folk medicine

Ethnopharmacological relevance: White flesh extract of Cocos nucifera (coconut) was studied to ascertain the ethnopharmacological standing of its antimalarial usage in Malaysian folk medicine. Materials and methods: The crude methanol extract was investigated for phytochemical constituents and acute oral toxicity. Antimalarial activity of different extract doses of 50, 100, 200 and 400 mg/kg were investigated in vivo against Plasmodium berghei (NK65) infections in mice during early, established and residual infections. Chloroquine (20 mg/kg) and pyrimethamine (1.2 mg/kg) were used as reference drugs. Results: The results revealed that the extract contained some phytochemical constituents and is toxicologically safe by oral administration. The extract significantly reduced the parasitaemia by the 200 and 400 mg/kg doses in the all three in vivo assessment assays. However, the extract did not significantly increase the survival time of the infected mice. Conclusions: The observed pharmacological activities suggest that the Malaysian folkloric medicinal application of Cocos nucifera has a pharmacological basis. (C) 2011 Elsevier Ireland Ltd. All rights reserved

Effect of methanolic extract of piper sarmentosum leaves on neointimal foam cell infiltration in rabbits fed with high cholesterol diet

Previous research has shown the beneficial effects of aqueous extract of Piper sarmentosum (P.s) on atherosclerosis. The first stage in atherosclerosis is the formation of foam cell. The aim of this study was to investigate the effect of the methanol extract of P.s on fatty streaks by calculating neointimal foam cell infiltration in rabbits fed with high cholesterol diet. Thirty six male New Zealand white rabbits were divided equally into six groups: (i) C: control group fed normal rabbit chow; (ii) CH: cholesterol diet (1 cholesterol); (iii) PM1: 1 cholesterol with methanol extract of P.s (62.5 mg/kg); (iv) PM2: 1 cholesterol with methanol extract of P.s (125 mg/kg); (v) PM3: 1 cholesterol with methanol extract of P.s (250 mg/kg); (vi) SMV group fed 1 cholesterol supplemented with Simvistatin drug (1.2 mg/kg). All animals were treated for 10 weeks. At the end of the treatment, the rabbits were fasted and sacrificed and the aortic tissues were collected for histological studies to measure the area of the neointimal foam cell infiltration using software. The thickening of intima ratio of atherosclerosis and morphological changes by scanning electron microscope were measured. The results showed that the atherosclerotic group had significantly bigger area of fatty streak compared to the control group. The area of fatty streak in the abdominal aorta was significantly reduced in the treatment groups which were similar with the SMV group. Similarly, there was a reduction in the number of foam cell in the treatment groups compared to the atherosclerotic group as seen under scanning microscope. In conclusion, histological study demonstrated that the methanol extract of the P.s could reduce the neointimal foam cell infiltration in the lumen of the aorta and the atherosclerotic lesion

Happiness among dentists: a multi-scale, multi-national study from 21 countries

Objectives: The extent to which dentists are happy with their profession and their life has not been well studied. The present study aimed to explore the level of happiness, satisfaction with life and psychological well-being among a sample of dental professionals from 21 countries. Materials and Methods: The sample comprised 2,200 dentists from 21 countries. Three scales – Subjective Happiness Scale (SHS), Satisfaction With Life Scale (SWLS), and Affect Balance Scale (ABS) – were used to measure the subjective responses. Data related to demographic and social characteristics were recorded. Mann–Whitney and Kruskal–Wallis tests were used as appropriate. Scales were correlated, and multiple linear regression analyses were employed to identify the independent determinants of SHS, SWLS and ABS. Data were analysed using the SPSS software program; a value of P lt 0.05 was considered significant. Results: The overall mean scores of SHS, SWLS and ABS were 18.53 ± 5.06, 23.06 ± 6.25 and 1.26 ± 2.40, respectively, with significant differences found across countries: dentists working in Croatia, Peru and Serbia recorded the highest scores, unlike dentists practicing in Yemen, Syria, and Iraq, who recorded the lowest scores. There were significant, moderately positive correlations between the various scales: SHS and SWLS: r = 0.535, P  lt  0.001; SHS and ABS: r = 0.58, P  lt  0.001; and SWLS and ABS: r = 0.533, P  lt  0.001. Country of practice, age, qualification and monthly income were the significant independent predictors of SHS, SWLS and ABS. Conclusion: Country of residence and social characteristics were associated with dentists’ responses regarding their feelings and subjective well-being