Preparation of an AgI/CuBi2O4 heterojunction on a fluorine-doped tin oxide electrode for cathodic photoelectrochemical assays: application to the detection of L-cysteine.

Photocathodic methods in photoelectrochemical (PEC) analysis are based on the use of functional photocathodes. Heterojunction cathodes consisting of different kinds of semiconductors are being considered as favorite schemes when compared to the single-component ones. A semiconductor heterojunction between CuBi2O4 (CBO) and other semiconductors has not been exploited in PEC assays so far. Herein, CBO nanospheres were initially electrochemically deposited on a fluorine-doped tin oxide (FTO) conductive glass and then coupled to chemically deposited AgI nanoparticles to obtain an electrode of type AgI/CBO/FTO. It was applied as a cathode in the PEC detection of L-cysteine as a model analyte. The sensor can selectively detect L-cysteine, and it is assumed that this is due to the selective interaction between the L-cysteine and both copper and silver via the formation of Cu-S and Ag-S bonds. The photocurrent of the electrode increases linearly with the logarithm of the cysteine concentration in the range from 0.1 and 50 µM, and the detection limit is 0.1 µM. Graphical abstract Schematic presentation of the preparation of an AgI/CuBi2O4 (AgI/CBO) heterojunction on a fluorine-doped tin oxide (FTO) electrode and its application to the cathodic photoelectrochemical detection of L-cysteine.

[Sperm DNA damage and unexplained recurrent spontaneous abortion].

OBJECTIVE: To explore the relationship of sperm DNA damage with unexplained recurrent spontaneous abortion (URSA). METHODS: Sperm DNA fragmentation was evaluated by sperm chromatin dispersion (SCD), and the results were expressed in terms of DNA fragmentation index (DFI). DFIs were measured in the male partners of 56 women with URSA (the experiment group) and of 31 without URSA (the control group). RESULTS: The DFI was shown to be (11.0% - 56.9%) in the experiment group, 21 (37.5%) of the subjects over 30%, as compared with (10.0% -36.8%) in the control group, only 8 (25.8%) of the subjects over 30%, significantly higher in the former than in the latter (29.4% vs 25.5%, P < 0.05). CONCLUSION: There is a relationship between sperm DNA damage and URSA.

[Effect of adenosine on electrophysiological changes of ventricular myocardium in rats with experimental diabetes].

OBJECTIVE: To investigate the electrophysiological changes of ventricular myocardium of rats with experimental diabetes and the effect of adenosine on its electrophysiology. METHODS: Diabetes was induced in male SD rats, using a single injection of alloxan into tail vein. Untreated animals were used as controls. The electrocardiograms (ECG) were recorded 6 weeks after diabetes was induced. Effects of adenosine on ventricular myocardium in diabetic rats and controls were observed by measuring the transmembrane potentials with conventional glass microelectrodes. RESULTS: QT interval in ECG and action potential duration (APD) at all levels (APD30, APD50, APD70 and APD90) were significantly prolonged in right ventricular papillary muscle 6 week after diabetes was induced. No differences were observed in the resting membrane potential (RP), action potential amplitude (APA) and overshoot (OS) as well as the maximum rate of depolarization (Vmax) between the diabetic rats and control rats. At concentration of 10 approximately 400 micromol/L, ADO had little influence on all transmembrane potential parameters of right ventricular papillary muscle in diabetic rats and controls. At 500 micromol/L, ADO shortened APD30, APD50, APD70 and APD90 of control group, while having no effect on diabetic rats. CONCLUSION: QT interval in ECG and APD at all levels are significantly prolonged in right ventricular papillary muscle of experimentally induced-diabetic rats.