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In vitro diagnosis requires target biomarkers to be reliably detected at an ultralow level. A dual-signal strategy permits self-calibration to overcome the interferences of experimental and environmental factors, and thus is regarded as a promising approach. However, currently reported works mainly concentrated on the same forms of energy of output signals. Herein, we propose a one-step strategy for synthesis of methylene blue-encapsulated zeolitic imidazolate framework-90 (MB@ZIF-90) with high loading, unique dual-signal property, exceptional recognition capability, and good stability, and we further pioneer MB@ZIF-90 as a dual-signal biosensor for label-free, enzyme-free, and ultrasensitive detection of adenosine triphosphate (ATP) by integration of fluorescence and homogeneous electrochemical techniques. The recognition of MB@ZIF-90 by target ATP spurs the decomposition of ZIF-90, subsequently permitting MB to be released into a supernatant. As compared to the case where ATP does not exist, obviously increased intensities in fluorescence and differential pulse voltammetry current are observed and both signals are directly proportional to ATP concentrations. Thus, the MB@ZIF-90-based biosensor achieved dual-signal detection of ATP in an ultrasensitive manner and displayed a more reliable diagnosis result than previously reported ATP biosensors. This dual-signal strategy provides a new opportunity to develop high-performance biosensors for in vitro diagnosis and demonstrates great potential for future applications in bioinformatics and clinical medicine.

Previous studies have suggested that testosterone levels are linked to a variety of diseases, such as cardiovascular disease, type-2 diabetes, the metabolic syndrome, erectile dysfunction, depression, stroke and osteoporosis. since cigarette smoking is a major health problem and highly prevalent among men, several groups have studied the effects of cigarette smoking on testosterone levels in men. However, the results have been conflicting. Our objectives were to examine the association of cigarette smoking and serum levels of sex hormone-binding globulin (sHbG), total testosterone (tt) and free testosterone (Ft) in a large male population. Data from 2,021 men (989 nonsmokers and 1,032 smokers), aged 20-69, were collected from the Fangchenggang Area Male Health and Examination survey using an in-person interview and self-administered questionnaires from september to December, 2009. We have found the following: (a) smokers had significantly higher tt and Ft levels compared to nonsmokers, even after stratification as per age, bMI, triglycerides and alcohol consumption. (b) both tt (r = -0.083, P <0.001) and Ft (r = -0.271, P <0.001) levels were negatively correlated to the amount of tobacco exposure. (c) smoking was an independent influencing factor for the levels of both tt (unadjusted Or = 1.64, 95% cI: 1.33-2.01, P <0.001; adjusted Or = 1.69, 95% cI: 1.34-2.13, P <0.001) and Ft (unadjusted Or = 1.32, 95% cI: 1.08-1.61, P = 0.007; adjusted Or = 1.27, 95% cI: 1-1.61, P = 0.050) levels in multivariate logistic regression models before and after adjusting for age, bMI, fasting blood glucose, triglycerides, alcohol consumption and estradiol. (d) smoking was not found to be an independent predictor of sHbG level after adjustment for confounders in multivariate regression model (P >0.05), although a positive HORMONES 2013, 12(4):567-577 Research paperAddress for correspondence: Zengnan Mo, MD, Tel.:+86-7715353342, Fax: +86-7715353342, E-mail: zengnanmo@hotmail.com Received 17-03-2012, Accepted 04-08-2012 568 Wei WaNg eT aL association between increasing pack-years and sHbG level was observed (r = 0.174, P <0.001). More research is needed to elucidate the biological mechanisms and clinical significance of these associations.

A carbene-catalyzed reductive coupling reaction of carboxylic esters and substituted Hantzsch esters is disclosed. Key steps of this reaction include one-electron reduction of a carbene catalyst-bound acyl azolium intermediate to generate the corresponding radical intermediate for subsequent alkylation reactions. The reaction is promoted by irradiation with visible light without the involvement of transition-metal photocatalysts. Mechanistic studies suggest that direct photoexcitation of the in situ formed acyl azolium intermediate is likely responsible for this light-induced one-electron-reduction process. Photoexcitation converts the acyl azolium intermediate to a single-electron oxidant, enabling single-electron oxidation of Hantzsch esters to generate radical intermediates. Our reactions work well for a broad range of aryl carboxylic ester and Hantzsch ester substrates. Sophisticated structures, including those present in medicines, can be incorporated into ketone molecules using our approach via very mild conditions that tolerate various functional groups.

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