Effect of 0.25 and 2.0 MeV He-ion irradiation on short-range ordering in model (EFDA) Fe-Cr alloys

The effect of He+ ion irradiation on a distribution of Cr atoms in model (EFDA) Fe(100-x)Cr(x) (x=5.8, 10.75, 15.15) was studied by means of conversion electrons Mossbauer spectroscopy. The alloys were irradiated to the dose of 1.2E16 ions per cm2 (7.5 dpa) with He+ of 0.25 and 2.0 MeV. The distribution of Cr atoms within the first two coordination shells around the probe Fe atoms was expressed in terms of the Warren-Cowley short-range order parameters alpha1 (first-neighbour shell, 1NN), alpha2 (second-neighbour shell, 2NN) and alpha12 (1NN+2NN. In non-irradiated alloys alpha1 was positive and alpha2 was negative for all three samples which indicates an ordering of Cr atoms. Yet, the value of alpha12 were close to zero, i.e. the distribution of Cr atoms averaged over the first two coordination shells around the probe Fe atoms, was random. The effect of the irradiation of the Fe5Cr sample is similar for the two energies of the He+ projectiles viz. increase of number of Cr atoms in the 1NN and decrease in the 2NN shell. Consequently, the degree of the ordering increased. For the other two samples, the effect of the irradiation depends on the composition, and it is stronger for the less energetic ions where, in the case of Fe10Cr, the disordering disappeared and some traces of Cr clustering (alpha12 weakly positive) can be seen. In the Fe15Cr sample the clustering is clear. In the samples irradiated with 2.0 MeV ions the ordering also survived in the samples with x=10.75 and 15.15, although its degree became smaller than in the Fe5Cr sample. Small changes in the magnetic texture were revealed.Comment: 19 pages, 11 figures, 41 references. arXiv admin note: text overlap with arXiv:1402.561

Intracoronary Blood Flow Velocity and Transstenotic Pressure Drop in an Awake Human Being During Coronary Vasodilation

The pressure drop over a coronary stenosis and the intracoronary Doppler blood flow velocity were measured at rest and during coronary vasodilation. We report the first observation that confirms the validity of fluid dynamic equations to describe the hemodynamics of a coronary stenosis based on quantitative arteriography in a human being. (J Interven Cardiol 1988:1:1) Copyrigh

Drug-eluting stents: current issues

Early stent thrombosis occurs in about 1% to 1.5% of patients with drug-eluting stents, very similar to the rate with bare-metal stents. Late stent thrombosis is more of a concern with drug-eluting stents, with an incidence of at least 0.35%. I would urge caution if you feel you have to stop antiplatelet therapy in patients with drug-eluting stents. While neointima formation peaks at 6 months and then may actually regress with bare-metal stents, it continues to grow with drug-eluting stents--although this process appears to plateau by 4 years with sirolimus. With the others, we have to wait and see. We still don't know the best drug-eluting stent. Trials are under way to compare stents with surgery, and the future brings the arrival of a number of exciting new devices and approaches that are now entering clinical trials

Thrombolysis of acute total occlusion of the left main coronary artery in evolving myocardial infarction

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