Redox-Active Tin Metal-Organic Framework with a Thiolate-Based Ligand.

Metal-organic frameworks (MOFs) and coordination polymers composed of thiolates as coordinating functional groups are interesting materials with unique optical and electronical properties. Herein, we report the preparation of KGF-4 and KGF-10, two Sn-MOF crystal structures with bonds between Sn and thiolate. KGF-10 was isolated as a pure phase and found to exhibit redox properties and a semiconducting band structure, as confirmed by first-principles (density functional theory) calculations.

Paraben exposure and semen quality of Japanese male partners of subfertile couples.

OBJECTIVES: Possible relationship between semen quality (semen volume, sperm concentration and sperm motility) and parabens exposure was investigated in male partners of couples who visited a gynecology clinic in Tokyo for infertility consultation (n = 42, 36.8 ± 5.4 years). METHODS: Semen parameters were measured according to WHO guideline at the clinic, and urinary methyl- (MP), ethyl- (EP), propyl- (PP) and butyl (BP) paraben concentrations were measured with liquid chromatography-tandem mass spectrometry. RESULTS: Geometric mean urinary concentrations (geometric standard deviation) of the subjects were 48.2 (4.52), 1.88 (4.72), 1.13 (6.75) and 0.184 (11.1) ng/mL for MP, EP, PP and BP, respectively. No significant association was found between semen parameters and urinary paraben concentrations in multiple regression analyses and logistic regression analyses. CONCLUSIONS: Two reasons of the absence of adverse effects on semen quality might be suggested: lower paraben exposure level of the subjects and small sample size. Further investigation of effect of paraben exposure among general male population at environmental levels is warranted.

Urinary inorganic arsenic concentrations and semen quality of male partners of subfertile couples in Tokyo.

Inorganic arsenic (iAs) has been known as a testicular toxicant in experimental rodents. Possible association between iAs exposure and semen quality (semen volume, sperm concentration, and sperm motility) was explored in male partners of couples (n = 42) who visited a gynecology clinic in Tokyo for infertility consultation. Semen parameters were measured according to WHO guideline at the clinic, and urinary iAs and methylarsonic acid (MMA), and dimethylarsinic acid concentrations were determined by liquid chromatography-hydride generation-ICP mass spectrometry. Biological attributes, dietary habits, and exposure levels to other chemicals with known effects on semen parameters were taken into consideration as covariates. Multiple regression analyses and logistic regression analyses did not find iAs exposure as significant contributor to semen parameters. Lower exposure level of subjects (estimated to be 0.5 µg kg(-1) day(-1)) was considered a reason of the absence of adverse effects on semen parameters, which were seen in rodents dosed with 4-7.5 mg kg(-1).

Comparison of different urine pretreatments for biological monitoring of pyrethroid insecticides.

During a cross-validation practice of urinary analysis of pyrethroid insecticide metabolite (3-phenoxybenzoic acid, 3-PBA) by two laboratories (Lab A and Lab B), difference in 3-PBA concentration was noticed. The analytical methods used in the exercise were enzymatic deconjugation (glucuronidase/sulfatase) followed by solid phase extraction and isotope dilution LC-MS-MS determination (Lab A) and acidic deconjugation followed by liquid-liquid extraction and gas chromatography-mass spectrometry determination (Lab B). A significant difference was found for one of the five samples: lower value was obtained in Lab A. Use of acidic deconjugation in Lab A resulted in comparable value with the analytical result for this sample originally obtained in Lab B. The comparison was extended to 42 urine samples taken from Japanese males in Lab A by using the two different deconjugation methods and LC-MS-MS determination. Significantly lower value was obtained for enzymatic deconjugation in some of the 42 urine samples. The results suggested the presence of other conjugated species of 3-PBA than glucuronide and sulfate in human urine. Although the overall agreement between the values obtained by the deconjugation methods was fair, it appears that urine samples should be pretreated by acidic deconjugation for the analysis in biological monitoring of pyrethroid exposure.

Endocrine disrupting chemicals in urine of Japanese male partners of subfertile couples: a pilot study on exposure and semen quality.

The concentrations of chemicals with suspected endocrine disrupting effect were measured in urine samples collected from 42 Japanese male partners of couples who had infertility consultation at a gynecology clinic in Tokyo. The urinary analytes included metabolites of 5 phthalate diesters, pyrethroid insecticide (3-phenoxybenzoic acid, 3-PBA) and soy isoflavones (daidzein and equol), and cadmium. The semen parameters (semen volume, concentration and motility) of the male subjects were examined at the clinic as a diagnostic screening. Multiple regression analysis using one of the semen parameters examined as dependent variable and urinary biomarkers with age, body mass index, abstinent period, alcohol drinking, smoking and consumption frequency of selected foods as independent variables. For sperm concentration, urinary mono-n-butyl phthalate was selected as a significant independent variable with positive beta, while urinary daidzein was with negative beta. Consumption frequency of coffee (negative) and fruits (positive) were also significant. For sperm motility, urinary 3-PBA was selected as significant with negative beta as well as detectability of equol and frequency of coffee consumption with negative beta while smoking was with positive beta. This pilot study suggested the pyrethroid exposure level and dietary habit (coffee and soy products) as a significant contributor to poorer semen quality.