Extended cavity quantum cascade laser with cavity resonator integrated grating filter.

We report on an extended cavity quantum cascade laser based on a cavity resonator integrated grating filter (CRIGF) that acts as both cavity end-reflector and spectral selector. Stable, mode-hop free, single-mode emission around 2150 cm-1 is obtained over large injection current ranges (more than 50 mA) with a typical threshold around 290 mA. A digital frequency tuning over more than 65 cm-1 is obtained by changing the periodicity of the CRIGF ending the extended cavity.

Mid-infrared cavity resonator integrated grating filters.

Cavity Resonator Grating Filters (CRIGFs) working in the Mid-Infrared are reported, with narrow-band resonant reflectivity peaks around 2200 cm-1 (4.6 µm). They are fabricated in the GaAs/AlGaAs material system that can potentially cover the whole [1-12] µm spectral range. TE-polarized peak reflectivity is 30% with a 4 cm-1 full width at half maximum.

Tunable graded cavity resonator integrated grating filters.

We demonstrated Graded Cavity Resonator Integrated Grating Filters (G-CRIGFs) that are narrowband spectral reflectors, spectrally tunable over more than 40 nm around 850 nm using a spatial gradient. A simple analytical model is introduced and validated experimentally to determine spectral performance of G-CRIGFs from the spectral properties of a standard Cavity Resonator Integrated Grating Filter (CRIGF).

Characterization of substance P-membrane interaction by transferred nuclear Overhauser effect.

Substance P, one of the mammalian tachykinins, is known to interact strongly with lipid bilayers and this interaction may play a role in the receptor-peptide recognition process. The conformation of substance P bound to vesicles consisting of perdeuterated phosphatidylcholine has been investigated by means of two-dimensional transferred nuclear Overhauser (trNOE) spectroscopy. Nuclear magnetic resonance data analysis resulted in a unique conformational family characterized by a well-defined conformation of the last seven C-terminal amino acids, which consists of a sequence of nonstandard turns following each other in a helix-like manner. The absence of short- or medium-range trNOE in the N-terminal part indicates its structural flexibility.

Naturalistic observation of athletic drug-use patterns and behavior in professional-caliber bodybuilders.

Athletic performance-enhancing drug use is widespread. Awareness in the medical community lags because various athletic subcultures have not been penetrated by conventional medical literature. This report presents a current and comprehensive assessment of drugs used by professional-caliber bodybuilders to enhance athletic performance. The scale of drug use documented significantly exceeds all previous reports from athletic populations and indicates that this group is at significant risk for use. Drug-use patterns and behavior encompass multiple domestic, foreign, and veterinary agents to create "successful" training programs. The presence of interathlete and intersport communication at amateur and professional levels creates a wide application for this information in athletic settings. Since use may not be limited to the competitive athlete, a heightened awareness will aid practitioners in correlating clinical observations with accurate athletic drug-use information.

Implantación de stent coronario por angina de pecho recurrente secundaria a puente muscular / Coronary stent placement for recurrent angina secondary to myocardial bridging: report of two cases

Myocardial bridging of the epicardic coronary arteries is not an uncommon finding in angiographic or necropsic studies. Patients who have symptoms usually improve with medical treatment. However, in refractory patients a surgical myotomy of overlying myocardium and/or a coronary bypass may be needed. We report two patients with long myocardial bridges in the mid-left anterior descending coronary artery, who had recurrent angina refractory to conventional treatment. In both patients two consecutive coronary stents were successfully implanted. At five and six months follow-up they are asymptomatic and with good exercise tolerance

Structure of a novel glycopeptidolipid antigen containing a O-methylated serine isolated from Mycobacterium xenopi. Complete 1H-NMR and 13C-NMR assignment.

GPL X-1, a novel glycopeptidolipid (GPL) isolated from Mycobacterium xenopi (CIPT 140 35004), has recently been found to typify a new class of mycobacterial glycopeptidolipids devoid of C-mycoside core structure, the so-called serine-containing glycopeptidolipid [Rivière, M. & Puzo, G. (1991) J. Biol. Chem. 266, 9057-9063]. Here we report the purification and characterization of a novel serine-containing GPL termed GPL X-IIb, isolated from the M. xenopi strain NCTC 10042. On thin-layer chromatography, this GPL was found to be present in some other M. xenopi strains isolated from patients with pulmonary infections. The sugar and amino-acid compositions of this GPL were elucidated from the native form using a combination of two-dimensional homonuclear and heteronuclear scalar coupling NMR. The peptide and sugar sequences, as well as the methoxyl group locations on the C-3 of the 6-deoxy-alpha-L-talopyranoside (6dTalp) and on a Ser, were unambiguously determined by heteronuclear multiple-bond correlation experiments. GPL X-IIb was found to be composed of a lipotetrapeptide of the following structure C12-Ser-OMe-Ser-Phe-aThr-OMe (aThr = allothreonine). The sugar part is made up of 3OMe-alpha-L-6dTalp and the following disaccharide: alpha-L-Rhap-(1-->3)-2-O-Lau-alpha-L-Rhap (Rhap = rhanmopyranose). Unlike GPL X-I, the sugar attachment sites on the tetrapeptide were successfully determined from heteronuclear three-bond coupling correlation observed in the heteronuclear multiple bond correlation spectrum between the anomeric carbon resonances and the beta protons of aThr-OMe and Ser. It was established that the 3OMe-6dTalp glycosylates the Ser while the disaccharide is linked to the aThr-OMe. Thus both GPL X-I and GPL X-IIb share a common lipotetrapeptide core [with the exception of Ser(OMe)] but drastically differ in their oligosaccharide appendage. Thus, by analogy with the M. avium complex, the present report suggests that M. xenopi species can be divided in various serovars characterized by the unique structure of their C-mycoside GPL oligosaccharide appendage, enhancing the interest for this new type of serine-containing glycopeptidolipid.