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Cu2ZnSnSe4 (CZTSe) nanoparticles (NPs) were successfully synthesized via a solvothermal method. Their structural, compositional, morphological, optoelectronic, and electrochemical properties have been characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), UV–vis absorption spectroscopy, and electrochemical impedance spectroscopy (EIS) techniques. Porosimetry and specific surface area in terms of the Brunauer–Emmett–Teller (BET) technique have also been studied. XRD indicates the formation of a polycrystalline kesterite CZTSe phase. Raman peaks at 173 and 190 cm−1 confirm the formation of a pure phase. TEM micrographs revealed the presence of nanoparticles with average sizes of ~90 nm. A BET surface area of 7 m2/g was determined. The CZTSe NPs showed a bandgap of 1.0 eV and a p-type semiconducting behavior. As a proof of concept, for the first time, the CZTSe NPs have been used as a visible-light-driven photocatalyst to Congo red (CR) azo dye degradation. The nanophotocatalyst material under simulated sunlight results in almost complete degradation (96%) of CR dye after 70 min, following a pseudo-second-order kinetic model (rate constant of 0.334 min−1). The prepared CZTSe was reusable and can be repeatedly used to remove CR dye from aqueous solutions. [ABSTRACT FROM AUTHOR]

A hydrothermal method was successfully employed to synthesize kesterite Cu2ZnSnS4 (CZTS) nanoparticles. X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and optical ultraviolet-visible (UV-vis) spectroscopy were used for characterization of structural, chemical, morphological, and optical properties. XRD results confirmed that a nanocrystalline CZTS phase corresponding to the kesterite structure was formed. Raman analysis confirmed the existence of single pure phase CZTS. XPS results revealed the oxidation states as Cu+, Zn2+, Sn4+, and S2−. FESEM and TEM micrograph images revealed the presence of nanoparticles with average sizes between 7 nm to 60 nm. The synthesized CZTS nanoparticles bandgap was found to be 1.5 eV which is optimal for solar photocatalytic degradation applications. The properties as a semiconductor material were evaluated through the Mott–Schottky analysis. The photocatalytic activity of CZTS has been investigated through photodegradation of Congo red azo dye solution under solar simulation light irradiation, proving to be an excellent photo-catalyst for CR where 90.2% degradation could be achieved in just 60 min. Furthermore, the prepared CZTS was reusable and can be repeatedly used to remove Congo red dye from aqueous solutions. [ABSTRACT FROM AUTHOR]

Studies the modulatory role of peroxynitrite in glucose oxidation in neurons and astrocytes in primary culture. Nitric oxide-mediated apoptosis; Rapid stimulation of pentose phosphate pathway activity; Activation of glucose-6-phosphate dehydrogenase.

There is an increasing body of evidence demonstrating that inhibition of cytochrome c oxidase by nitric oxide (NO) may be one more step in a signaling cascade involved in the physiologic regulation of cell functions. For example, in both astrocytes and neurons the inhibition of mitochondrial respiration by endogenously produced NO induces transient and modest decreases in cellular ATP concentrations. This mitochondrial impairment may serve as a cellular sensor of energy charges, hence modulating metabolic pathways, such as glycolysis, through AMP-activated protein kinase (AMPK) in astrocytes. In neurons, the NO derivative peroxynitrite anion triggers signaling pathways leading to glucose oxidation through the pentose-phosphate pathway to form reducing equivalents in the form of NADPH. The modulation of these metabolic pathways by nitric oxide or its derivatives may be important for understanding the mechanisms by which this free radical affects neuronal death or survival., ((c) 2004 Wiley-Liss, Inc.)