Pressure-dependent structural and electronic properties of quasi-one-dimensional (TMTTF)2PF6.

We have performed detailed x-ray investigations of the quasi-one-dimensional organic conductor (TMTTF)(2)PF(6) at room temperature and hydrostatic pressures up to 27 kbar. Based on the pressure-dependent crystal structure, the electronic band structure was calculated by density functional theory (DFT). Our systematic study provides important information on the coupling among the organic molecules but also to the anions. We discuss the consequences for the electronic properties and compare them with optical investigations under pressure. The increasing plasma frequency observed perpendicular to the stacks corresponds to a widening of the bands for the b-direction. Around 20 kbar a dimensional crossover occurs from a one-dimensional Mott insulator to a two-dimensional metal.

[Diagnostic image (244). A neonate with a hypoplastic lower leg]. / Diagnose in beeld (244). Een neonaat met een hypoplastisch onderbeen.

In a male neonate with left lower leg hypoplasia, a bowed shin bone and a skin dimple, fibular aplasia type II was diagnosed.

A new pairwise folding potential based on improved decoy generation and side-chain packing.

A new force field for pairwise residue interactions as a function of C(alpha) to C(alpha) distances is presented. The force field was developed through the solution of a linear programming formulation with large sets of constraints. The constraints are based on the construction of >80,000 low-energy decoys for a set of proteins and requiring the decoy energies for each protein system to be higher than the native conformation of that particular protein. The generation of a robust force field was facilitated by the use of a novel decoy generation process, which involved the rational selection of proteins to add to the training set and included a significant energy minimization of the decoys. The force field was tested on a large set of decoys for various proteins not included in the training set and shown to perform well compared with a leading force field in identifying the native conformation for these proteins.

[Hospital results of salvage angioplasty with coronary stenting after failure of thrombolysis in the acute phase of myocardial infarction]. / Résultats hospitaliers de l'angioplastie de sauvetage avec implantation d'endoprothèses coronaires après échec de thrombolyse à la phase aiguë de l'infarctus du myocarde.

Between December 1991 and February 19999, 25 patients (56 +/- 10 years) underwent salvage angioplasty with coronary stenting after failure of thrombolysis (TIMI 2), rtPA (N = 18), n-PA (N = 4), K2-tu-PA (N = 2) and streptokinase (N = 1). All were treated by aspirin and 96% were given ticlopidine for one month. The culprit artery was the left anterior descending (48%), the left circumflex (8%) or the right coronary (44%). The average ejection fraction was 41%; 4 patients (16%) had cardiogenic shock. The stents were implanted for occlusive coronary dissection (36%), threatening dissection (40%), partial result of angioplasty (20%) or of first intention (4%). In all, 31 stents were implanted (1.2 +/- 0.57 stent/target lesion ratio with an average length of 20.9 +/- 10.2 mm). The stents were tabular in 51% of cases. The angiographic success rate (TIMI 3 and residual stenosis < 50%) was 96% with maximum inflation pressures of 13.7 +/- 2.5 atm and balloons with an average diameter of 3.3 +/- 0.5 mm. Intra-aortic balloon pumping was required in 7 patients (28%). The 30 day results included a mortality rate of 16% (4 patients), a recurrence of infarction in 4%; there were no repeat angioplasties, coronary bypass surgery or blood transfusions. The predictive factors of recurrent coronary events were: age over 60 (p = 0.04), multivessel coronary disease (p = 0.007), cardiogenic shock (p = 0.004) and left ventricular dysfunction (p = 0.015). The authors conclude that cases of failure of thrombolysis are at high risk and that salvage angioplasty with coronary stenting is associated with excellent angiographic results. Patients with cardiogenic shock, however, have a high mortality, irrespective of coronary patency and the use of intra-aortic balloon pumping.

[Incidental CT discovery of an isolated thrombus in the aortic arch]. / Découverte scanographique fortuite d'un thrombus isolé de l'arche aortique.

The authors report a case of isolated thrombus of the aortic arch discovered incidentally during thoracic CT angiography, complicated by clinical features of embolic renal infarction despite introduction of anticoagulant treatment. This case confirms the value of transoesophageal echocardiography to diagnose and follow these lesions and illustrates the therapeutic approach following discovery of aortic thrombi.

Predator-induced diel vertical migration inDaphnia: Enrichment and preliminary chemical characterization of a kairomone exuded by fish.

Planktivorous fish release a cue of an unknown chemical nature into the water that induces diel vertical migration inDaphnia as predator avoidance response. We used a bioassay to obtain information about the chemical nature of the kairomone. We present a method to enrich the cue from holding water of fish by sorbent extraction. The kairomone exuded byLeucaspius delineatus can be characterized as a nonolefinic low-molecular-weight anion of intermediate lipophilicity. The presence of amino groups in the molecule can be excluded, whereas hydroxy groups are essential for activity. Separation by HPLC yielded only one active fraction. The kairomones released byCarassius carassius andRutilus rutilus showed the same chemical characteristics, suggesting that the kairomones from different species of fish, sensed byDaphia, are very similar, if not identical.