Introduction: Computer Tomography Angiograph (CTA) can assess coronary atherosclerosis which is an important substrate for acute coronary syndrome contributing to cardiovascular morbidity and mortality. However, CTA findings alone cannot adequately predict the risk of arterial plaque instability that is likely more dependent on their biomechanical environments. This study is to investigate biomechanical modelling of CTA using fluid-structure interaction (FSI) simulation of coronary artery atherosclerosis.

The LCLS generates linearly polarized, intense, high brightness x-ray pulses from planar fixed-gap undulators. While the fixed-gap design supports a very successful and tightly controlled alignment concept, it provides only limited taper capability (up to 1% through canted pole and horizontal position adjustability) and lacks polarization control. The latter is of great importance for soft x-ray experiments. A new compact out-of-vacuum undulator design (Delta), based on a 30-cm-long in-vacuum prototype at Cornell University, is being developed and tested to add those missing properties to the LCLS undulator line. Tuning Delta undulators within tight, FEL type tolerances is a challenge due to the fact that the magnetic axis and the magnet blocks are not easily accessible for measurements and tuning in the fully assembled state. An R&D project is underway to install a 3.2-m long out-of-vacuum device in place of the last LCLS undulator, to provide controllable levels of polarized radiation and to develop measurement and tuning techniques to achieve x-ray FEL type tolerances. Presently, the installation of the device is scheduled for August 2014.

SummaryFondaparinux is widely approved for prophylaxis and treatment of venous thromboembolic events (VTE). However, its longer half-life time compared to heparins limits its peri-procedural use. Aim: To investigate 3h peak and 24h baseline concentrations of fondaparinux when administered for prophylaxis (1 x 2.5 mg qd). Secondary outcome measures: incidences of VTE, bleedings, HIT, allergic skin reactions, 30 days mortality. Patients, methods: Between 02/2010 and 03/2011, 3h peak and 24h baseline levels of fondaparinux were measured with a chromogenic anti-FXa method in 75 consecutive patients. Medical data were obtained from patients' records. Results: The 5% and 95% percentile of the 3h peak level were 0.20 μg/ml and 0.83 μg/ml (median: 0.53 μg/ml), and of the 24h baseline level 0.08 μg/ml and 0.53 μg/ml (median 0.21 μg/ml), respectively. An inverse correlation was found between fondaparinux levels and GFRs (rho=-0.617 (3h); rho=-0.648 (24h); p=0.01). Shorter (≤5 days) or longer (≥8 days) duration of prior fondaparinux exposure showed no significantly different 3h peak/24h baseline levels (p>0.6). One progressive thrombosis occurred but no major bleedings, HIT, allergic skin reactions or fatalities. Conclusions: After fondaparinux exposure, >75% of the patients still had relevant prophylactic 24h baseline levels. This did not coincide with a high rate of bleeding events. Due to the low patient number in this study undergoing surgery or interventions, it remains to be investigated whether or at which concentrations the bleeding risk is increased when baseline levels are within prophylactic ranges.

Zum Nachweis einer Plättchenfunktionsstörung stehen verschiedene Testmethoden zur Verfügung, mit denen sowohl angeborene Thrombozytendefekte als auch erworbene Störungen der Thrombozytenfunktion erfasst werden können. Die induzierte Thrombozytenaggregation unter Einsatz verschiedener Aktivatoren, wie ADP, Kollagen, Arachidonsäure oder Ristocetin, stellt dabei den Standard der Thrombozytenfunktionsdiagnostik dar. Neben der Abklärung einer Blutungsneigung werden die Thrombozytenfunktionstestsysteme auch zur Ermittlung eines ausreichenden antithrombozytären Therapieansprechens verwendet. Studien zeigen, dass eine gesteigerte Thrombozyteninhibierung durch individuelle Veränderung der antithrombozytären Therapie bei laborchemisch nachgewiesener Non-Response zu einer Prognoseverbesserung führt, sodass die Identifikation von Patienten mit inadäquatem Ansprechen auf eine Acetylsalicylsäure- oder Clopidogreltherapie von großer Wichtigkeit ist. Bisher hat sich jedoch noch kein Testverfahren der Thrombozytenaggregationsdiagnostik als Standardmethode für diese Indikation durchgesetzt.

Summary Both for diagnosis of congenital and acquired platelet dysfunction as well as for therapy monitoring after application of platelet function inhibitors various methods have been established for evaluation of platelet function. In contrast to the gold standard of platelet function testing, the light transmission aggregometry in platelet rich plasma the Point-of-care (POC) analyzers allow fast analysis of platelet function without extensive laboratory work up. The conditions of the pre-analytical phase, however, are still of enormous importance in the prevention of medical errors. There is increasing clinical data in monitoring the effect of platelet aggregation inhibitors, showing that quantitative determination of the platelet function degree correlates with risk of increased bleeding or stent thrombosis. However, it is still unclear, which is the optimal test system, to predict the clinical outcome of these patients.

Numerous laboratory tests are in use to detect congenital or acquired platelet function disorders. Platelet aggregometry, using ADP, collagen, arachidonic acid or ristocetin as inductor is the standard test system for diagnosis. It is also used to detect platelet non-response to antiplatelet therapy. Studies have demonstrated that laboratory assessment of platelet non response to aspirin or clopidogrel is associated with adverse outcomes, and they indicate the importance of adjusting antiplatelet therapy in patients with a low degree of platelet inhibition. Nevertheless, a standardized method for identifying these patients is still missing.

Both for diagnosis of congenital and acquired platelet dysfunction as well as for therapy monitoring after application of platelet function inhibitors various methods have been established for evaluation of platelet function. In contrast to the gold standard of platelet function testing, the light transmission aggregometry in platelet rich plasma the Point-of-care (POC) analyzers allow fast analysis of platelet function without extensive laboratory work up. The conditions of the pre-analytical phase, however, are still of enormous importance in the prevention of medical errors There is increasing clinical data in monitoring the effect of platelet aggregation inhibitors, showing that quantitative determination of the platelet function degree correlates with risk of increased bleeding or stent thrombosis. However, it is still unclear, which is the optimal test system, to predict the clinical outcome of these patients.

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LCs) to improve reliability and longevity since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and gammas. Examples include NdFeB magnets, considered for the damping rings, injection and extraction lines and final focus; electronic, electro- and fiber-optics to be utilized in detector readout, accelerator controls and the CCDs required for the vertex detector; as well as high and low temperature superconducting materials (LTSMs) for cavities and some magnets. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were for NdFeB materials at EPACO4[1]. We have extended the doses, included more manufacturer's samples and measured radioactivities. We also added L and HTSMs and various semiconductor and electro-optic materials such as photonic band-gap (PBG) fiber that we studied previously with gamma rays.

The Stanford Linear Accelerator Center is evaluating the feasibility of placing a free electron laser (FEL) at the end of the linear accelerator. The proposal is to inject electrons two thirds of the way down the linac, accelerate the electrons for the last one third of the linac, and then send the electrons into the FEL. This project is known as the LCLS (Linac Coherent Light Source). To test the feasibility of the LCLS, a smaller experiment VISA (Visual to Infrared SASE (Self Amplified Stimulated Emission) Amplifier) is being performed at Brookhaven National Laboratory. VISA consists of four wiggler segments, each 0.99 m long. The four segments are required to be aligned to the beam axis with an rms error less than 50 {micro}m [1]. This very demanding alignment is carried out in two steps [2]. First the segments are fiducialized using a pulsed wire system. Then the wiggler segments are placed along a reference laser beam which coincides with the electron beam axis. In the wiggler segment fiducialization, a wire is stretched through a wiggler segment and a current pulse is sent down the wire. The deflection of the wire is monitored. The deflection gives information about the electronmore » beam trajectory. The wire is moved until its x position, the coordinate without wire sag, is on the ideal beam trajectory. (The y position is obtained by rotating the wiggler 90{sup o}.) Once the wire is on the ideal beam trajectory, the wire's location is measured relative to tooling balls on the wiggler segment. To locate the wire, a device was constructed which measures the wire position relative to tooling balls on the device. The device is called the wire finder. It will be discussed in this paper. To place the magnets along the reference laser beam, the position of the laser beam must be determined. A device which can locate the laser beam relative to tooling balls was constructed and is also discussed in this paper. This device is called the laser finder. With a total alignment error budget less than 50 {micro}m, both the fiducialization and magnet placement must be performed with errors much smaller than 50 {micro}m. It is desired to keep the errors from the wire finder and laser finder at the few {micro}m level.« less

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and γ’s over the life of the facility[1]. While the linacs will be superconducting, there are still many uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the situation for rare earth, permanent magnet materials was presented at PAC03[2]. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC04[3]. We have extended the doses, included other manufacturer’s samples, and measured induced radioactivities which are discussed in detail.

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to -20% and effective lengths from 324 mm to 972 mm,. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use samarium cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype

The Next Linear Collider (NLC) will require over 5600 magnets, each of which must be highly reliable and/or quickly repairable in order that the NLC reach its 85% overall availability goal. A multidiscipline engineering team was assembled at SLAC to develop a more reliable electromagnet design than historically had been achieved at SLAC. This team carried out a Failure Mode and Effects Analysis (FMEA) on a standard SLAC quadrupole magnet system. They overcame a number of longstanding design prejudices, producing 10 major design changes. This paper describes how a prototype magnet was constructed and the extensive testing carried out on it to prove full functionality with an improvement in reliability. The magnet's fabrication cost will be compared to the cost of a magnet with the same requirements made in the historic SLAC way. The NLC will use over 1600 of these 12.7 mm bore quadrupoles with a range of integrated strengths from 0.6 to 132 Tesla, a maximum gradient of 135 Tesla per meter, an adjustment range of 0 to -20% and core lengths from 324 mm to 972 mm. The magnetic center must remain stable to within I micron during the 20% adjustment. A magnetic measurement set-up has been developed that can measure sub-micron shifts of a magnetic center. The prototype satisfied the center shift requirement over the full range of integrated strengths.

The second phase accelerator for the Dual Axis Hydrodynamic Test facility (DARHT) is designed to provide an electron beam pulse that is 2 microsec long, 2kA, and 20 MeV in particle energy. The injector provides 3.2 MeV so that the linac need only provide 16.8 MeV. The linac is made with two types of induction accelerator cells. The first block of 8 cells have a 14 in. beam pipe compared to 10 in. in the remaining 80 cells. The other principal difference is that the first 8 cells have reduced volt-sec in their induction cores as a result of a larger diameter beam pipe. The cells are designed for very reliable high voltage operation. The insulator is Mycalex. Results from prototype tests are given including results from solenoid measurements. Each cell contains a solenoid for beam transport and a set of x-y correction coils to reduce corkscrew motion. Details of tests to determine RF mode impedances relevant to BBU generation are given. Blocks of cells are separated by "intercells" some of which contain transport solenoids. The intercells provide vacuum pumping stations as well. Issues of alignment and installation are discussed.

In the context of the SLAC PEP-II asymmetric e+e− collider and the BaBar detector with its 1.5 T solenoid, we have calculated and measured the fringe field at the nearby beam elements and at the position of the photomultipliers external to the return iron but within a specially designed iron shield. The comparisons of these measurements with the simulations based on finite element analysis are remarkably good, within about 5 G at the most critical beam element. The field at the photomultipliers is less than 1 G, in agreement with the simulation. With a simple method of demagnetization of the shield, a maximum field of 0.6 G is obtained.