Precise analyses of photoelectrochemical reactions on particulate Zn0.25Cd0.75Se photoanodes in nonaqueous electrolytes using Ru bipyridyl complexes as a probe.

Recombination of photoexcited carriers at interface states is generally believed to strongly govern the photoelectrochemical (PEC) performance of semiconductors in electrolytes. Sacrificial reagents (e.g., methanol or Na2SO3) are often used to assess the ideal PEC performance of photoanodes in cases of minimised interfacial recombination kinetics as well as accelerated surface reaction kinetics. However, varying the sacrificial reagents in the electrolyte means simultaneously changing the equilibrium potential and the number of electrons required to perform the sacrificial reaction, and thus the thermodynamic and kinetic aspects of the PEC reactions cannot be distinguished. In the present study, we propose an alternative methodology to experimentally evaluate the energy levels of interfacial recombination centres that can reduce PEC performance. We prepare nonaqueous electrolytes containing three different Ru complexes with different bipyridyl ligands; redox reactions of Ru complexes represent one-electron processes with similar charge transfer rates and diffusion coefficients. Therefore, the Ru complexes can serve as a probe to isolate and evaluate only the thermodynamic aspects of PEC reactions. Recombination centres at the interface between a nonaqueous electrolyte and a Zn0.25Cd0.75Se particulate photoanode are elucidated using this method as a model case. The energy level at which photocorrosion proceeds is also determined.

Subclinical generation of acyclovir-resistant herpes simplex virus with mutation of homopolymeric guanosine strings during acyclovir therapy.

BACKGROUND: Suppressive therapy in patients with genital herpes has been used in Japan since 2006. Susceptibility and resistance of herpes simplex virus (HSV)-2 to acyclovir were examined in genital isolates from patients receiving suppressive therapy and compared with those from those naïve to acyclovir and receiving episodic treatment with acyclovir. OBJECTIVE: The aim of this study was to analyze the effect of acyclovir use on the susceptibility to acyclovir and analysis of the thymidine kinase gene by acyclovir treatment. METHODS: Genital HSV isolates were obtained from three patients groups. Susceptibility to acyclovir, the frequency of acyclovir-resistant clones and mutations in the thymidine kinase gene of acyclovir-resistant clones were determined. RESULTS: Susceptibility to ACV was significantly higher in isolates from patients receiving suppressive therapy than those naïve to acyclovir and receiving episodic treatment, but the frequencies of resistant clones were similar among the three groups. Mutation in guanosine homopolymeric strings (G-string mutation) was significantly more frequent in clones during episodic treatment and suppressive therapy than clones from patients naïve to ACV. The frequency of G-string mutation was significantly less frequent in isolates from patients naïve to ACV than those experienced ACV therapy. CONCLUSION: The frequency of acyclovir-resistant mutants was not increased by episodic and suppressive therapy, but exposure to acyclovir significantly generated G-string mutations, possibly induced by acyclovir. Acyclovir therapy had no substantial effects on the susceptibility of HSV-2 or frequency of resistant virus but did generate subclinical G-string mutants in patients' HSV-2.

Intestinal cryptosporidiosis as an initial manifestation in a previously healthy Japanese patient with AIDS.

BACKGROUND: Cryptosporidium parvum infection has been recognized as one of the pathogens causing severe and persistent diarrhea in immunodeficient patients, such as those with AIDS, worldwide. However, in Japan, the frequency of this infection has been rare, except for environmental contamination through the water supply. In this communication, we describe a Japanese patient with AIDS presenting with intestinal Cryptosporidiosis as an initial manifestation. METHODS: The oocysts of Cryptosporidium parvum in his stool were detected by the Ziehl-Neelsen method and electron microscopy. The antigen-specificity was proved by immunostaining, using a fluorescein isothiocyanate (FITC)-labeled monoclonal antibody and enzyme-linked immunosorbent assay (ELISA), using Cryptosporidium-specific antibody. RESULTS: A 28-year-old Japanese homosexual man was admitted to our hospital because of severe watery diarrhea of 1-week duration. Numerous oocysts of Cryptosporidium parvum were observed in his stool. Cryptosporidium parvum antigen was detected in stool samples. Serological examinations revealed that anti-HIV-1 antibody was positive, and HIV RNA was positive at a high level. He was diagnosed as having AIDS associated with intestinal Cryptosporidiosis. The circulating CD4+ T-cell count was 152/microl. His diarrhea was not alleviated by administration of loperamide and an ordinary antibiotic agent, but ultimately resolved by the administration of the macrolide antibiotic agent, clarithromycin. CONCLUSIONS: We emphasize that the presence of Cryptosporidium parvum infection should be kept in mind in searching for pathogens causative of severe diarrhea in AIDS patients.

[Antimicrobial susceptibility and beta-lactamase producibility of bacteria clinically isolated during the period from December 1999 to February 2000].

Antimicrobial susceptibility and beta-lactamase producibility were tested in 848 clinical strains collected at 8 hospitals in Kanagawa prefecture during the period from December 1999 to February 2000. Positive rates of beta-lactamase used the nitrocefin method (Cefinase) were 21.9% of Staphylococcus aureus, 10.0% of Haemophilus influenzae, and 99.0% of Moraxella catarrhalis. Furthermore, on the acidometric method (P/Case test) penicillinase (PCase), cephalosporinase (CEPase), and both of PCase and CEPase were found to be positive in 19.0%, 16.0%, and 16.0% for Escherichia coli, 6.2/0/3.1% for Klebsiella pneumoniae, 0/66.3/26.5% for Enterobacter cloacae, 2.8/57.7/15.5% for Serratia marcescens, and 4.0/15.0/22.0% for Pseudomonas aeruginosa, respectively. Based on the assessment of minimal inhibitory concentrations (MICs) of antibacterial agents among beta-lactamase producing strains, there were 5 strains (4 strains of K. pneumoniae and 1 strain of E. coli) that may be ESBLs producing bacteria out of a total of 466 strains of Enterobacteriaceae and P. aeruginosa. During this process, 1 strain of class-B beta-lactamase-producing E. cloacae was isolated. MRSA were found in 79.2% of S. aureus, and BLNAR were found in 8.9% of H. influenzae.