The first beam measurements with a cold-bore superconducting in-vacuum undulator in a storage ring are reported. Undulators are x-ray generators in light sources. The physical limitations of these devices limit the intensity and the brilliance of the x-ray beam. At present the undulators are made from permanent magnets. It was shown in earlier papers that at low electron beam intensities superconductive wires in the vacuum beam pipe can overcome the limitations inherent to permanent magnet undulators. It was argued that the use of these novel devices in light sources with high beam currents may be limited by the extreme anomalous skin effect regime in Cu at 4.2 K, which has so far undergone very little investigation, and the power deposited by the infrared part of the synchrotron radiation. The purpose of this paper is to present measurements of these effects at the synchrotron light source ANKA with stored currents up to 200 mA.

The beam heat load and the pressure in the vacuum chamber of the cold bore superconducting undulator installed at ANKA (ANgstrom source KArlsruhe) have been monitored for almost two years. Possible sources of the observed heat load could be synchrotron radiation from upstream magnets, image currents, electron and ion bombardment. In this paper, the various possible contributions to the heat load are discussed and compared with experimental results. The dynamic pressure increases nonlinearly with the average beam current. The current where it assumes a maximum varies both with the bunch intensity and with the initial vacuum pressure. A correlation between the heat load and the dynamic pressure has been observed. This study suggests that electron bombardment could explain the beam heat load and pressure rise observed for a bunch length of 10 mm.

A large spectrum of methods has been used in both routine and scientific studies of the hemostatic system. The particular interest of the investigators has been focused on methods simultaneously evaluating clotting and fibrinolysis processes. The aim of the present study was to develop an optical method for overall evaluation of clot formation and lysis (CL-test) that could be used in drug screening. The CL-test was performed in citrate plasma diluted with Tris-buffered saline. Thrombin was applied for plasma clotting (0.5 IU/ml), while tissue plasminogen activator (60 ng/ml) was used for fibrinolysis activation. Clot formation and lysis were monitored in thermostatic conditions (37 degrees C) as a continuous record of transmittance change. By means of own computer program, kinetic parameters of the processes studied and plasma overall clot formation and fibrinolysis potential, expressed as the area under the clotgeneration and fibrinolysis curves, were calculated. The CL-test was developed and checked by evaluation of the effect, on clot formation and lysis, of various concentrations of acetylsalicylic acid (a drug that affects hemostasis), aprotinin (fibrinolysis activator) and venoruton (fibrinolysis inhibitor). The obtained results confirmed that the test we propose for monitoring clot formation, stabilization and lysis is sensitive and enables precise estimation of the processes studied. In our opinion, it can be a useful tool in drug screening investigations.

IntroductionIt is generally assumed that cholesterol reduction by statins is the predominant therapeutic result underlying their beneficial effects in cardiovascular disease. However, the action of statins may be partially independent of their effects on plasma cholesterol levels, as they combine lipid lowering with positive effects on hemorheological conditions and endothelial function. We evaluated the impact of statin treatment on platelet adhesion to fibrinogen (spontaneous and ADP-activated), along with ADP, collagen or ristocetin-induced aggregation in type II hyperlipidemic patients.Material and methodsThe study group included 70 persons: 50 patients affected by type II hyperlipidemia without concomitant diseases and 20 healthy volunteers. The effects of 8-week statin treatment (atorvastatin 10 mg/day, simvastatin 20 mg/day, or pravastatin 20 mg/day) on platelet activation were evaluated.ResultsRegardless of the type of statin, a significant decrease in ADP-induced platelet aggregation was observed: for atorvastatin 50.6 ±12.8% vs. 41.1 ±15.8% (p < 0.05), for simvastatin 57.2 ±18.0% vs. 44.7 ±22.1% (p = 0.05), and for pravastatin 55.8 ±19.5% vs. 38.8 ±23.3% (p < 0.05). There was no significant effect of statins on collagen or ristocetin-induced platelet aggregation and adhesion.ConclusionsTherapy with statins beneficially modifies ADP-induced platelet aggregation in patients with hyperlipidemia and does not affect spontaneous or ADP-induced platelet adhesion to fibrinogen and platelet aggregation induced by collagen or ristocetin.

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