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Purpose – The purpose of this paper is to develop a new simple technique to synthesize graphene film on a flexible polyethylene terephthalate (PET) substrate and applied as a strain sensor. Design/methodology/approach – Graphene film was synthesized using laser treatment of graphene oxide (GO) film deposited on PET substrate. A universal laser system was used to simultaneously reduce and pattern the GO film into laser reduced graphene oxide (LRGO) film. Findings – The laser treatment synthesizes a multilayer graphene film with overlapped flakes, which shows structure integrity, mechanical flexibility and electrical conductivity of 1,330 S/m. The developed LRGO/PET film was used to fabricate a high sensitivity strain sensor. The sensitivity and temperature dependency of its gauge factor (GF) was examined at applied strains up to 0.25 per cent and operating temperatures up to 80°C. The fabricated sensor shows stable GF of approximately 78 up to 60°C with standard error of the mean not exceeding approximately ± 0.2. Originality/value – The proposed method offers a new simple and productive technique of fabricating large-scale graphene-based flexible devices at a low cost. [ABSTRACT FROM AUTHOR]

An inorganic/organic hybrid composite of CuS nanoparticles (NPs) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was prepared via a facile mixing process. Counter electrodes (CEs) of quantum dot sensitized solar cells (QDSSCs) were prepared by coating the hybrid CuS-PEDOT:PSS composite on fluoride-doped tin oxide (FTO) substrates using simple drop-casting technique. The SEM micrographs of CuS-PEDOT:PSS CEs revealed three-dimensional surface morphology and homogeneous dispersion of CuS NPs on the PEDOT:PSS. The electrochemical measurements of the hybrid CEs showed high electrocatalytic activity towards polysulfide electrolyte resulted from embedding the catalytic active CuS NPs into the continuous PEDOT:PSS conducting matrix. The CdS-QDSSC fabricated with CuS- PEDOT:PSS CE exhibited an remarkable stable power conversion efficiency (PCE) of 1.04%, that is higher than that of Pt CE (0.48%) measured under one-sun illumination. The enhancements in the photovoltaic performance of QDSSCs fabricated with hybrid CEs are discussed based on the analysis of electrochemical results. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the possible radioprotective effect of Costus speciosus and carnosine as natural antioxidants in order to control the hyperglycemia developed in male albino rats exposed to acute oxidative stress induced by gamma radiation. Methods: Twenty-eight adult male albino rats were divided into four groups. The first group was taken as a control group, while the three other groups were exposed to γ irradiation at a single 7.5 Gy dose. Furthermore, the rats in the second and third groups were i.p. injected with Costus speciosus root powder and carnosine, respectively. On the 3rd day, after irradiation, the serum levels of glucose, insulin, C peptide, copper, iron, calcium, total antioxidant capacity (TAC) and malondialdehyde (MDA) were measureded. Results: The results revealed that exposure to γ irradiation induced significant increases in serum glucose, iron, and malondialdehyde. However, the levels of serum calcium, copper, total antioxidant capacity and insulin significantly decreased (p < 0.05). A significant decrease was observed in C peptide in the exposed group, compared to control group. All the test parameters indicate improvement after treatment with Costus speciosus and carnosine (p < 0.05). Conclusion: Costus speciosus and carnosine ameliorate the effect of gamma radiation, indicating their role as antidiabetic agents and radioprotectors; however, Costus speciosus was critically more efficient than carnosine. [ABSTRACT FROM AUTHOR]