Behavior of High Strength Concrete Containing Rice Husk Ash (RHA) and Superplasticizer

Rice-husk is a waste product that cause pollution aud disposal problem. Rice-husk ash however has been acknowledged as a natural pozzolan that cau contribute in concrete industry with its high silica contain aud easily obtained with very low cost. This paper presents the results of au experimental investigation regarding the effect of microwave incinerated rice-husk ash (MIRRA) into the mix of high strength concrete, in which the source of ricehusk is from BERNAS rice paddy milling industry in Malaysia. Five trial mix proportion containing MIRRA were design and cast into cubes, cylinders and slabs in the laboratory aud the strength development of the hardened concrete investigated. From the observation, MIRRA accelerate the hydration process aud provide the cube with high compressive strength capability at early age (i.e 3 day). This is due to high silica contain in the MIRRA which is proved by the XRD test at SIRIM facilities. The investigation showed that it is possible to cast concrete with strength above 70MPa by using locally available rice-husk. It cau be concluded that MIRRA provides high compressive strength at early age and the contribution of MIRRA is similar to silica fume

Behavior of High Strength Concrete Containing Rice Husk Ash (RHA) and Superplasticizer

Rice-husk is a waste product that cause pollution aud disposal problem. Rice-husk ash however has been acknowledged as a natural pozzolan that cau contribute in concrete industry with its high silica contain aud easily obtained with very low cost. This paper presents the results of au experimental investigation regarding the effect of microwave incinerated rice-husk ash (MIRRA) into the mix of high strength concrete, in which the source of ricehusk is from BERNAS rice paddy milling industry in Malaysia. Five trial mix proportion containing MIRRA were design and cast into cubes, cylinders and slabs in the laboratory aud the strength development of the hardened concrete investigated. From the observation, MIRRA accelerate the hydration process aud provide the cube with high compressive strength capability at early age (i.e 3 day). This is due to high silica contain in the MIRRA which is proved by the XRD test at SIRIM facilities. The investigation showed that it is possible to cast concrete with strength above 70MPa by using locally available rice-husk. It cau be concluded that MIRRA provides high compressive strength at early age and the contribution of MIRRA is similar to silica fume

One step closer to understanding the role of bacteria in diabetic foot ulcers: characterising the microbiome of ulcers

Background: The aim of this study was to characterise the microbiome of new and recurrent diabetic foot ulcers using 16S amplicon sequencing (16S AS), allowing the identification of a wider range of bacterial species that may be important in the development of chronicity in these debilitating wounds. Twenty patients not receiving antibiotics for the past three months were selected, with swabs taken from each individual for culture and 16S AS. DNA was isolated using a combination of bead beating and kit extraction. Samples were sequenced on the Illumina Hiseq 2500 platform. Results: Conventional laboratory culture showed positive growth from only 55 % of the patients, whereas 16S AS was positive for 75 % of the patients (41 unique genera, representing 82 different operational taxonomic units (OTU’s). S. aureus was isolated in 72 % of culture-positive samples, whereas the most commonly detected bacteria in all ulcers were Peptoniphilusspp., Anaerococcus spp. and Corynebacterium spp., with the addition of Staphylococcus spp. in new ulcers. The majority of OTU’s residing in both new and recurrent ulcers (over 67 %) were identified as facultative or strict anaerobic Gram-positive organisms. Principal component analysis (PCA) showed no difference in clustering between the two groups (new and recurrent ulcers). Conclusions: The abundance of anaerobic bacteria has important implications for treatment as it suggests that the microbiome of each ulcer “starts afresh” and that, although diverse, are not distinctly different from one another with respect to new or recurrent ulcers. Therefore, when considering antibiotic therapy the duration of current ulceration may be a more important consideration than a history of healed ulcer

Inhibition of arachidonic acid metabolism and its implication on cell proliferation and tumour-angiogenesis

Arachidonic acid (AA) and its metabolites have recently generated a heightened interest due to growing evidence of their significant role in cancer biology. Thus, inhibitors of the AA cascade, first and foremost COX inhibitors, which have originally been of interest in the treatment of inflammatory conditions and certain types of cardiovascular disease, are now attracting attention as an arsenal against cancer. An increasing number of investigations support their role in cancer chemoprevention, although the precise molecular mechanisms that link levels of AA, and its metabolites, with cancer progression have still to be elucidated. This article provides an overview of the AA cascade and focuses on the roles of its inhibitors and their implication in cancer treatment. In particular, emphasis is placed on the inhibition of cell proliferation and neo-angiogenesis through inhibition of the enzymes COX-2, 5-LOX and CYP450. Downstream effects of inhibition of AA metabolites are analysed and the molecular mechanisms of action of a selected number of inhibitors of catalytic pathways reviewed. Lastly, the benefits of dietary omega-3 fatty acids and their mechanisms of action leading to reduced cancer risk and impeded cancer cell growth are mentioned. Finally, a proposal is put forward, suggesting a novel and integrated approach in viewing the molecular mechanisms and complex interactions responsible for the involvement of AA metabolites in carcinogenesis and the protective effects of omega-3 fatty acids in inflammation and tumour prevention

THE EFFECT OF FLY ASH/ALKALINE ACTIVATOR RATIO IN CLASS F FLY ASH BASED GEOPOLYMERS

This study focused on the effect of fly ash/alkaline activator ratio and Na2SiO3/NaOH ratio in class F based geopolymers. The objective of this study is to observe the variation of the compressive strength of the final product depending the solid/liquid ratio. In order to form the geopolymer, various parameters were changed during the geopolymerisation process. The fly ash/alkaline activator ratio studied was: 1.5; 2.0; 2.5. The geopolymeric pasta was heated up to 400 °C, 600 °C and 800 °C. After heating the compressive value of geopolymer, with the fly ash and alkaline activator ratio equal to 2 and Na2SiO3/NaOH ratio of 2.5, decreased with approximative 40 MPa comparative with the value of the sample obtained from the same composition dried for 7 days at normal temperatur

Assessment of dental caries predictors in 6-year-old school children - results from 5-year retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>This was a retrospective cohort study undertaken to assess the rate and pattern of dental caries development in 6-year-old school children followed-up for a period of 5 years, and to identify baseline risk factors that were associated with 5 years caries experience in Malaysian children.</p> <p>Methods</p> <p>This 5-years retrospective cohort study comprised primary school children initially aged 6 years in 2004. Caries experience of each child was recorded annually using World Health Organization criteria. The rates of dental caries were recorded in prevalence and incidence density of carious lesions from baseline to final examination. Risk assessment was done to assess relative risk for caries after 5 years in children with baseline caries status. Simple and multiple logistic regression analysis were performed to identify significant independent risk factors for caries.</p> <p>Results</p> <p>The sample consisted of 1830 school children. All components of DMFT showed significant differences between baseline and final examination. Filled teeth (FT) component of the DMFT showed the greatest increases. Results revealed the initial baseline caries level in permanent dentition was a strong predictor for future caries after 5 years (RR=3.78, 95% CI=3.48-4.10, P<it><</it>0.001). Logistic regression analysis showed significant association between caries occurrence and residence (urban/rural) (OR=1.80, <it>P</it><0.001). However, it was not significantly associated with gender and ethnicity. The incidence density of caries, affected persons (ID_p) observed from baseline and after 5 years was 5.80 persons/100 person-year of observation. The rate of new caries-affected tooth (ID_t) in the period from baseline and after 5-years was 0.76 teeth/100 teeth-year of observation.</p> <p>Conclusion</p> <p>The majority of 12-year-old school children (70%) were caries-free and most of the caries were concentrated in only a small proportion (30%) of them. We found that the presence of caries in permanent teeth at the age of 6 years was a strong predictor of future caries development in this population. The strong evidence of early permanent teeth caries at six years old to predict future caries incidence at 12-year-olds, which could be obtained at almost no cost, questions the need for and cost-effectiveness of expensive technology-based commercial caries predictions kits.</p

Evaluation of PD/PID controller for insulin control on blood glucose regulation in a Type-I diabetes

This project introduces a simulation of Proportional-Derivative (PD) and Proportional-Integral-Derivative (PID) controller based on a virtual Type 1 Diabetes Mellitus (T1DM) patient: Hovorka diabetic model using MATLABSimulink software. The results of these simulations are based on three tuning responses for each controller which are fast, slow and oscillation responses. The main purpose of this simulation is to achieve an acceptable stability and fastness response towards the regulation of glucose concentration using PD and PID controller response with insulin infusion rate. Therefore, in order to analyze and compare the responses of both controller performances, one-day simulations of the insulin-glucose dynamic have been conducted using a typical day meal plan that contains five meals of different bolus size. It is found that the PID closed-loop control with a short rise time is required to retrieve a satisfactory glucose regulation