Cooperative Lamb shift in an atomic vapor layer of nanometer thickness.

We present an experimental measurement of the cooperative Lamb shift and the Lorentz shift using a nanothickness atomic vapor layer with tunable thickness and atomic density. The cooperative Lamb shift arises due to the exchange of virtual photons between identical atoms. The interference between the forward and backward propagating virtual fields is confirmed by the thickness dependence of the shift, which has a spatial frequency equal to twice that of the optical field. The demonstration of cooperative interactions in an easily scalable system opens the door to a new domain for nonlinear optics.

Association between depression and subclinical carotid atherosclerosis in patients with Type 1 diabetes.

AIMS: Recent studies have suggested an association between depression and subclinical atherosclerosis as measured by presence of carotid atherosclerotic plaque and increased intima-media thickening in non-clinical populations. Given the high prevalence of depression in patients with Type 1 diabetes and the diabetes-related risk factors for atherosclerosis, we hypothesized that this relation might also be of special relevance in Type 1 diabetic patients. METHODS: Intima-media thickness (IMT) and the presence of plaques in the carotid arteries were quantitatively assessed by high-resolution ultrasound in 175 adults (89 men, 86 women) with an established diagnosis of Type 1 diabetes. Having been treated for depression or current Beck Depression Inventory scores > 10 were considered to indicate depression. RESULTS: In men, the risk of plaque was higher in depressed subjects relative to non-depressed participants after adjustment for age, smoking status, systolic blood pressure, dyslipidaemia and body mass index [odds ratio (OR) 5.19; 95% confidence interval (CI) 1.29, 20.81]. Depressed women did not have an increased risk of plaque compared with non-depressed women (OR 0.97; 95% 95% CI 0.22, 4.34). We did not observe an association between depression and IMT, in men or in women. CONCLUSIONS: In line with previous research, our findings suggest a link between depression and subclinical atherosclerosis in Type 1 diabetic men, but not in women.

Characterization of yeasts with high L[+]-lactic acid production: lactic acid specific soft-agar overlay (LASSO) and TAFE-patterns.

Only few yeast strains are known for the high level production of L[+]-lactate. We report indications for the conspecifity of Kluyveromyces thermotolerans (formerly Saccharomyces veronae) strain CBS 4728 with Stamm 42 (formerly Saccharomyces pretoriensis, RADLER 1984). We suggest that Stamm 42 has little, if any relationship to Saccharomyces cerevisiae. Furthermore, we have optimized the method of Subden et al. (1982) for the detection of lactate producing microorganisms. Using this method in a screening with 100 yeast strains of our institute collection, we could not find additional strains with high L[+]-lactate production. This method may provide a useful tool for the molecular cloning of the unique yeast L[+]-LDH1) gene (s).