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Theophylline, a bronchodilator used in the treatment of respiratory diseases, displays a narrow therapeutic range requiring therapeutic drug monitoring to maximize its effectiveness and safety. Current measurements of theophylline concentrations are, however, achieved using chromatography or immunoassays, which, in spite of their high accuracy and sensitivity, rely on expensive laboratory-based instruments operated by trained personnel or provide only semi-quantitative results, respectively. In response, we developed an electrochemical DNA aptamer-based (E-AB) sensor for theophylline on screen-printed electrodes. Our sensors enable rapid (

In this research, graphene aerogel (GA) was fabricated by chemical reduction method, in which ethylenediamine (EDA) was used as a reducing and functionalising agent. The characterisation of GA was studied by density, field-emission scanning electron microscope, Brunauer-Emmett-Teller (BET) specific surface area, Fourier transform infrared spectroscopy, and X-ray diffraction. The results of the analysis showed that GA exhibits low density, ranging from 4-8 mg/cm3, high porosity, and BET specific surface area changes from 176 to 1845 m2/g. It was found that the suitable content of EDA on the synthesis of GA is 30 µl. The obtained GA was used as an adsorbent for removal of oils and methylene blue (MB) from aqueous solutions. The maximum adsorption capacities of GA for lubricant and crude oils are 160 g/g and 110 g/g respectively. The effecting factors including pH, contact time, and initial concentrations on the adsorption capacity of GA for MB were investigated. The adsorption process of MB onto GA followed the pseudosecond-order kinetic and well-fitted to Langmuir isotherm model. The maximum adsorption capacity for MB from linear Langmuir model was calculated to be 212.76 mg/g at pH 7. Accordingly, GA could be used as a potential adsorbent for removal of oils and MB from water.

Today, more and more Vietnamese firms consider continuous improvement as the best way to increase their manufacturing capability. This paper aims to illustrate the effectiveness of manufacturing processes management from the Samsung production system (SPS) approach when it was implemented to improve capability of existing production process in Vietnamese firms. The paper is a combination of descriptive and field research to demonstrate how SPS principles are appropriate for five real industry cases in particular and all Vietnamese manufacturing companies in general. In five cases, the usage of SPS-based tools has turned out to be fruitful. They solved problems of continuous improvement management in Vietnamese firms and created significant achievements in quality improvement and productivity increase. The paper investigates the core value of Samsung's continuous process improvement. The way that Samsung has used to improve quality and profitability simultaneously can be adapted by manufacturing companies. [ABSTRACT FROM AUTHOR]

In this study, silver/reduced graphene oxide (Ag/rGO) nanocomposites were synthesized in situ using three different mass ratios of silver nitrate and graphene oxide (1:1, 2:1, and 4:1). L-ascorbic acid (LAA) was used as an environment-friendly reducing agent. The characterization of Ag/rGO was investigated using Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. The investigated results showed that the Ag/rGO nanocomposites were successfully synthesized with silver nanoparticles in the size range of 10-25 nm uniform distribution on rGO sheets. The antibacterial activity of Ag/rGO was tested against Gram-negative (Salmonella typhimurium) and Grampositive (Staphylococcus aureus) bacteria using plate colony-counting and broth dilution methods, in comparison with individual rGO and silver nanoparticles. The tested results showed that the Ag/rGO nanocomposite with the AgNO3:GO ratio of 4:1 (Ag/rGO4:1) exhibited the strongest antibacterial activity. The minimal inhibitory concentration values of Ag/rGO4:1 against Salmonella typhimurium and Staphylococcus aureus were 10 µg/ml and 50 µg/ml, respectively. Hence, the Ag/rGO nanocomposite could be considered as a potential antibacterial agent.

In this study, silver‐titanium dioxide/graphene aerogel (Ag−TiO2/GA−ATG) was synthesized via chemical reduction using ethylene diamine (EDA). The effects of reductant doses on the formation of the three‐dimensional structure and the photocatalytic degradation efficiency of ATG were evaluated with five different volumes (20, 30, 40, 50, and 60 μL), corresponding to the ATG1, ATG2, ATG3, and ATG4, respectively. The results showed that 40 μL of EDA was the suitable condition for the formation of ATG three‐dimensional structure. Characterizations revealed that ATG3 was successfully synthesized with distinctive peaks of Ag and TiO2 in the X‐ray diffraction patterns whilst scanning electron microscope and high resolution transmission electron microscope images showed a porous structure, silver nanoparticles and TiO2 with an average size of 10–25 nm were uniformly distributed on the graphene surface. Furthermore, ATG3 possessed the highest photocatalytic capability to deteriorate methyl orange with an efficiency of up to 99.53 % with a catalyst dose of 0.3 mg/mL, superior compared to those of TiO2 and TiO2/GA. The radicals scavenging experiments elucidated ⋅O2 ${{{\rm { O}}}_{{\rm { 2}}}^{{\rm { \char60 M-\char62 }}}}$ to majorly contribute to the photodegradation process. Moreover, ATG3 showed high recyclability, which retains 80 % of yield even after 10 cycles. Those findings proved that ATG has high potential in the environmental remediation field. [ABSTRACT FROM AUTHOR]