Showing papers by "Aix-Marseille University published in 1979"

Structure and sequence of the multihaem cytochrome c3.

Abstract: The molecular structure of cytochrome c3 isolated from Desulfovibrio desulfuricans has been solved on the basis of its crystallographic determination at 2.5 A resolution and of an essentially complete sequence. The molecule consists of a single polypeptide chain wrapped around a very compact core of four non-parallel haems which present a relatively high degree of exposure to the solvent. Alignment of the amino acid sequences of cytochrome c3 from several species suggests that the structure reported here is characteristic of the cytochrome c3 group.

Monte Carlo simulation of the crystal-melt interface of a Lennard-Jones substance

Abstract: The Monte Carlo method is used to study the properties of the interface between the (0001) face of a hexagonal-close-packed crystal of an idealized substance and its melt. The simulated system consists of 860 moveable ‘Lennard-Jones’ molecules, with boundary conditions periodic only in those directions parallel to the interface. The starting configuration is a computer-built dense hard-sphere model of the interface. After only a relatively short period of thermal equilibration, the potential energy remains essentially constant, and the system is considered as being in equilibrium. The principal results are (a) a density deficit at the interface and (b) a molecular mobility in the interfacial layer that is the same as that in the body of the liquid. Molecular mobility in the crystal layer adjacent to the interface is practically zero.

Transient left anterior hemiblock during angina pectoris: coronarographic aspects and clinical significance.

Abstract: The data of 6 patients in whom a left anterior hemiblock appeared in the course of angina pectoris attacks were reviewed. All 6 patients were found to fulfill the criteria for unstable angina. 1 patient who presented the features of Prinzmetal variant angina was included in this group. Coronary arteriography showed significant coronary artery disease in all 6 patients involving 3 vessels in 2 patients, 2 vessels in 1 and 1 vessel in 3. A severe lesion (70--100%) of the left anterior descending artery in the vicinity of the first perforator was demonstrated in every case. The 2 patients with 3-vessel disease were not operable and died 4 and 5 days after the hemodynamic study. These deaths were caused by myocardial infarction with cardiogenic shock in one case and intractable ventricular arrhythmias in the other case. 4 patients were operable and underwent aortocoronary saphenous bypass surgery. There were 2 operative deaths. The 2 survivors are asymptomatic 7 and 16 mth after surgery. This study suggest that transient left anterior hemiblock during an attack of angina pectoris may be a feature of impending myocardial infarction and may be indicative of a severe obstruction of the left anterior descending coronary artery.

Observation of NaClLiCl high‐temperature phases by gold decoration on the solid—melt interface of czochralski grown crystals

Abstract: Applying bubble method and gold decoration technique to the study of the crystal—melt interface of Czochralski grown mixed NaClLiCl crystals, with variable compositions, phase separation on a microscopic scale is observed in different domains of the phase diagram. The shape, surface morphology, and growth mechanism of these phases are discussed, sometimes in relation with the microscopic wetting of the growing interface by the melt. Durch Anwendung der Blaschen-Methode und der Golddekorationstechnik auf die Untersuchung der Grenzflache Kristall-Schmelze von nach dem Czochralski-Verfahren gezuchteten NaClLiCl-Mischkristallen variabler Zusammensetzung wird in verschiedenen Bereichen des Phasendiagramms eine Phasentrennung von mikroskopischer Grosenordnung beobachtet. Die Kristallform, Oberflachenmorphologie und der Wachstumsmechanismus dieser Phasen werden diskutiert, zum Teil in Beziehung zu einer mikroskopischen Benetzung der Grenzflache durch die Schmelze.