Alterations of Hair and Nail Content of Selected Trace Elements in Nonoccupationally Exposed Patients with Chronic Depression from Different Geographical Regions.

The aim of this study was to determine if altered levels of selected trace elements manifest themselves during chronic depression. To identify elements strongly associated with chronic depression, relationships between the elemental contents of hair and nails and the interelement correlations were checked. Inductively coupled plasma mass spectrometry and ion chromatography were used to evaluate the contents of Zn, Cu, Co, Pb, Mn, and Fe in hair and nail samples from a total of 415 subjects (295 patients and 120 healthy volunteers). The study included logistic regression models to predict the probability of chronic depression. To investigate possible intercorrelations among the studied elements, the scaled principal component analysis was used. The research has revealed differences in TE levels in the group of depressed men and women in comparison to the healthy subjects. Statistically significant differences in both hair and nails contents of several elements were observed. Our study also provides strong evidence that the intermediary metabolism of certain elements is age- and gender-dependent. Zn, Mn, Pb, and Fe contents in hair/nails seem to be strongly associated with chronic depression. We found no statistically significant residence-related differences in the contents of studied elements in nonoccupationally exposed patients and healthy subjects.

Polarized photon-pairs heterodyne polarimetry for ultrasensitive optical activity detection of a chiral medium.

A polarized photon-pairs heterodyne polarimetry is proposed in order to measure in an ultrasensitive manner the circular birefringence of a chiral medium via optical rotation detection. A balanced detector is integrated into this polarimeter. Thus, shot-noise-limited detection by this polarimeter can be achieved. Experimentally, the detection sensitivity for the circular birefringence of a glucose-water solution up to partial differential |n(r) - n(l)| = 2 x 10(-11) at 10 mg/dL is verified. To our knowledge, this is the highest sensitivity ever measured of a chiral liquid solution based on single traveling sample cell geometry. Finally, when compared to a fiber loop ring-resonator in the frequency domain for a chiral liquid, this polarimeter shows an order of 10(4) enhancement on the sensitivity of natural optical activity measurement.

Optical activity measurement by use of a balanced detector optical heterodyne interferometer.

What we believe to be a novel amplitude sensitive optical heterodyne polarimeter in which a Zeeman laser is associated with balanced detector detection was set up. The aim was to measure the optical activity of a quartz crystal with a Cornu depolarizer at high accuracy. The features of this novel polarimeter, which include the use of a two-frequency laser that ensures the accuracy of the measurement, are discussed. Furthermore, the detection sensitivity of the optical activity of a quartz crystal was measured as 8.5x10(-10). To our knowledge, this is the highest sensitivity obtained for optical activity measurement of a quartz crystal when the error of the measurement is also analyzed.