A two-level full factorial design was used to analyze several factors involved in PSF-GO-Pebax thin film nanocomposite membranes development. Permeate flux was chosen as a single response for four possible factors: Pebax selective layer concentration, amount of GO load to Pebax selective layer, Pebax-GO selective layer thickness, and amount of GO load to PSF substrate. The study is aimed at factors interaction and contribution towards the highest permeation flux via FFD and RSM approach. R2 obtained from the ANOVA is 0.9937 with Pebax concentration as the highest contributing factor. Pebax concentration-amount of GO load to PSF substrate is the only interaction contributing to the highest flux. A regression analysis concluded the study with model development and an optimized condition for the membrane design.
A novel optical detection system consisting of combination of uricase/HRP-CdS quantum dots (QDs) for the determination of uric acid in urine sample is described. The QDs was used as an indicator to reveal fluorescence property of the system resulting from enzymatic reaction of uricase and HRP (horseradish peroxidase), which is involved in oxidizing uric acid to allaintoin and hydrogen peroxide. The hydrogen peroxide produced was able to quench the QDs fluorescence, which was proportional to uric acid concentration. The system demonstrated sufficient activity of uricase and HRP at a ratio of 5U:5U and pH 7.0. The linearity of the system toward uric acid was in the concentration range of 125-1000 µM with detection limit of 125 µM.
A semiconducting water-soluble core-shell quantum dots (QDs) system capped with thiolated ligand was used in this study for the sensitive detection of glucose in aqueous samples. The QDs selected are of CdSe-coated ZnS and were prepared in house based on a hot injection technique. The formation of ZnS shell at the outer surface of CdSe core was made via a specific process namely, SILAR (successive ionic layer adsorption and reaction). The distribution, morphology, and optical characteristics of the prepared core-shell QDs were assessed by transmission electron microscopy (TEM) and spectrofluorescence, respectively. From the analysis, the results show that the mean particle size of prepared QDs is in the range of 10-12 nm and that the optimum emission condition was displayed at 620 nm. Further, the prepared CdSe/ZnS core shell QDs were modified by means of a room temperature ligand-exchange method that involves six organic ligands, L-cysteine, L-histidine, thio-glycolic acid (TGA or mercapto-acetic acid, MAA), mercapto-propionic acid (MPA), mercapto-succinic acid (MSA), and mercapto-undecanoic acid (MUA). This process was chosen in order to maintain a very dense water solubilizing environment around the QDs surface. From the analysis, the results show that the CdSe/ZnS capped with TGA (CdSe/ZnS-TGA) exhibited the strongest fluorescence emission as compared to others; hence, it was tested further for the glucose detection after their treatment with glucose oxidase (GOx) and horseradish peroxidase (HRP) enzymes. Here in this study, the glucose detection is based on the fluorescence quenching effect of the QDs, which is correlated to the oxidative reactions occurred between the conjugated enzymes and glucose. From the analysis of results, it can be inferred that the resultant GOx:HRP/CdSe/ZnS-TGA QDs system can be a suitable platform for the fluorescence-based determination of glucose in the real samples.
Aim: Mothers knowledge and attitude toward childhood vaccination influence uptake is the most adequate tool and preventive aspects to infectious disease epidemics. The present study assesses and measures knowledge and attitude of postnatal mothers toward vaccination.Methods and results: The present study adopted a cross-sectional study design, whereby 200 postnatal mothers were identified during their postnatal visit to clinics. The subjects were accessed using questionnaire to assess the level of knowledge and attitude of mothers regarding vaccination. The objectives were to study the level of knowledge, the attitude, and to find the association between knowledge and attitude of the study subjects. The data were analyzed using SPSS version 16. The results was analyzed through chi-square test. The association between age (p = .031), education (p = .021), occupation (p = .013), and knowledge score toward vaccination was found to be statistically significant. However, ethnicity (p = .127), employment (p = .197), and mode of delivery (p = .750) toward mothers vaccination knowledge were not significant for the study. Mothers education, age, and occupation were found to be associated with attitude toward childhood vaccination. No association was found between ethnicity, employment, and mode of delivery with attitude of childhood vaccination.Conclusion: More than half of the studied mothers had good knowledge scores on vaccination, more than two-thirds of the studied mothers had good attitude scores on vaccination. However, the religious misconception and fear of autism was the main cause of vaccine resistance in Malaysia.