Prediction of key aroma development in coffees roasted to different degrees by colorimetric sensor array.

We developed a colorimetric sensor array (CSA) that is sensitive to highly contributory volatile compounds of coffee aroma for discrimination of coffee samples roasted to different roast degrees. Strecker aldehydes and α-diketones were significantly higher for the medium roast than the other roast degrees. The development of several sulfur compounds was pronounced in the medium-dark and dark roasts, except for dimethyl sulfide, which was only detected in the light roast. The CSA method coupled with principal component analysis or hierarchical cluster analysis successfully distinguished the roasted coffee samples according to roast degree. Partial least squares regression results showed that the CSA responses were well-correlated with the concentrations of volatile compounds in the coefficient of determination (rp2) range of 0.686-0.955. These results demonstrate that the CSA rapidly responded to coffee aroma compounds and was capable of predicting coffee aroma development.

Psychosocial Factors Associated with Suicide Re-attempts in Persons with Chronic Mental Disabilities in Korea.

Suicide re-attempters are clinically different from single-episode attempters and are at higher risk of completed suicide. This study explored psychosocial risk factors and modifiable factors related to suicide re-attempt in a representative sample of 441 chronic mentally disabled individuals in Seoul, Korea. The participants were listed on the public sector registry based on the Act for the Welfare of Disabled Persons. Individualized interviews were conducted, and the authors analyzed the data via multiple logistic regression analysis. The results showed that physical illness (under treatment OR 1.7; left untreated OR 4.2) and no leisure activities (OR 1.9) were factors related to a higher risk of re-attempted suicide. Unmet and modifiable needs in addition to mental health services should be considered to prevent suicide re-attempts in the chronic mentally disabled.

Application of magnetic and core-shell nanoparticles to determine enrofloxacin and its metabolite using laser induced fluorescence microscope.

A unique analytical method using nanoparticles and laser-induced fluorescence microscopy (LIFM) was developed to determine enrofloxacin in this work. For sample pretreatment, two different kinds of particles, i.e., synthesized dye-doped core-shell silica nanoparticles and magnetic micro-particles (MPs), were used for fluorescent tagging and concentrating the enrofloxacin, respectively. The antibody of enrofloxacin was immobilized on the synthesized FITC-doped core-shell nanoparticles, and the enrofloxacin target was extracted by the MPs. At this moment, the average number of antibodies on each core-shell silica nanoparticle was ~0.9, which was determined by the fluorescence ratiometric method. The described method was demonstrated for a meat sample to determine enrofloxacin using LIFM, and the result was compared with enzyme-linked immunosorbent assay (ELISA). The developed technique allowed the simplified analytical procedure, improved the detection limit about 54-fold compared to ELISA.