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Wang Z.,China University of Mining and Technology | Gao Q.,China University of Mining and Technology | Pan C.,China University of Mining and Technology | Zhao Y.,China University of Mining and Technology | And 2 more authors.
Inorganic Chemistry | Year: 2012

The thiosulfate-bromate reaction has been studied by high-performance liquid chromatography, monitoring the concentrations of thiosulfate and tetrathionate simultaneously. It is found that concentration-time curves of both species display a sigmoidal shape in a slightly acidic, well-buffered medium. Unlike the previously reported complex reaction systems involving bromate, this nonlinear dynamical behavior originates from neither proton nor bromine(III) autocatalysis under our experimental conditions. We demonstrated that sulfur(IV) species significantly accelerates the reaction; therefore, it acts as an autocatalyst. To the best of our knowledge, no reaction system has yet been reported among the pH-driven oxysulfur-oxyhalogen systems, where sulfur(IV) has such a remarkable role. On the basis of the simultaneous evaluation of [S 2O 3 2-] and [S 4O 6 2-] time series, an eight-step kinetic model is proposed to account for the experimental observations. The model employed here may serve as a solid starting point to extend it for other oxysulfur-oxyhalogen systems where such a seemingly general phenomenon may become observable. © 2012 American Chemical Society.

Li H.,Xiamen University | Li H.,University of Pecs | Nie J.C.,Beijing Normal University | Li J.C.,Xiamen University | And 2 more authors.
Carbon | Year: 2013

Ethanol has etching effect on the side wall of multiwalled carbon nanotubes (MWCNTs). Under proper treating temperature and employing ultrasonic treatment, graphene fractions might form and suspend in acetonitrile due to the ethanol induced breaking down of the ektexine of the MWCNTs. High resolution images by transmission electron microscopy validated these processes. Furthermore, due to the requirements of industrial applications, entropy driven selective adsorption was successfully tested for separation of the graphene layers from the remained MWCNTs. © 2012 Elsevier Ltd. All rights reserved.

Szabadfi K.,University of Pecs | Szabo A.,University of Pecs | Kiss P.,University of Pecs | Reglodi D.,University of Pecs | And 6 more authors.
Neurochemistry International | Year: 2014

Metabolic changes induced by diabetes lead to a multifactorial progressive disease of the retina with an extremely complex pathogenesis. One of the mechanisms of retinal cell death in diabetes is via apoptosis. Our previous results show that pituitary adenylate cyclase activating polypeptide (PACAP) attenuates the morphological and neurochemical changes in a rat model of diabetic retinopathy. The aim of this study was to investigate the mechanisms of this protective effect. Retinas of streptozotocin-induced diabetic rats were analyzed using apoptosis detection combined with immunolabeling. Western blot was used to measure levels of pro- and anti-apoptotic pathways. Intraocular PACAP injection markedly attenuated diabetic retinal injury: increased levels of the anti-apoptotic p-Akt, p-ERK1, p-ERK2, PKC, Bcl-2, while decreased levels of the pro-apoptotic p-p38MAPK and activated caspases (8, 3, 12) were detected. The number of apoptotic cells increased in all nuclear layers of diabetic retinas, but significantly decreased after PACAP treatment. Our results clearly demonstrate that the protective effects of PACAP are mediated, at least partly, by attenuating apoptosis, including also that of the dopaminergic amacrine cells. Inhibition of apoptosis is one of the PACAP-induced pathways with therapeutic potential in early experimental diabetic retinopathy. © 2013 Elsevier Ltd. All rights reserved.

Kunsagi-Mate S.,University of Pecs | Kunsagi-Mate S.,Janos Szentagothai Research Center | Iwata K.,Gakushuin University
Journal of Solution Chemistry | Year: 2013

The dynamic motions of solvent molecules in the solvation shell of phenols in binary water-ethanol solutions have been examined experimentally by measuring the solvent relaxation times using phase-fluorometry. The results show that the mono-exponential character of the solvent relaxation changes to bi-exponential just after the ethanol content of the bulk solution exceeds a critical value. This value depends on the electron density of the aromatic rings of the phenolic molecules. Above the critical values much higher ethanol content is observed in the solvation shell compared to the bulk solutions. This observation is applicable in wide scale of chemical processes in condensed phase and indicates that further research is needed towards development of a picture at the atomic scale. © 2012 Springer Science+Business Media New York.

Koszegi T.,University of Pecs | Koszegi T.,Janos Szentagothai Research Center | Poor M.,University of Pecs
Toxins | Year: 2016

Ochratoxin A (OTA) is a widely-spread mycotoxin all over the world causing major health risks. The focus of the present review is on the molecular and cellular interactions of OTA. In order to get better insight into the mechanism of its toxicity and on the several attempts made for prevention or attenuation of its toxic action, a detailed description is given on chemistry and toxicokinetics of this mycotoxin. The mode of action of OTA is not clearly understood yet, and seems to be very complex. Inhibition of protein synthesis and energy production, induction of oxidative stress, DNA adduct formation, as well as apoptosis/necrosis and cell cycle arrest are possibly involved in its toxic action. Since OTA binds very strongly to human and animal albumin, a major emphasis is done regarding OTA-albumin interaction. Displacement of OTA from albumin by drugs and by natural flavonoids are discussed in detail, hypothesizing their potentially beneficial effect in order to prevent or attenuate the OTA-induced toxic consequences. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

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