Dual Band Deep Ultraviolet AlGaN Photodetectors

We report on the design, fabrication and characterization of a back-illuminated voltage bias selectable dual-band AlGaN UV photodetector. The photodetector can separate UVA and W-B band radiation by bias switching a two terminal n-p-n homojunction structure that is fabricated in the same pixel. When a forward bias is applied between the top and bottom electrodes, the detector can sense UV-A and reject W-B band radiation. Alternatively, under reverse bias, the photodetector can sense UV-B and reject UV-A band radiation

A Finite Element Analysis of a Crack Penetrating or Deflecting into an Interface in a Thin Laminate

The crack tip driving force of a crack growing from a pre-crack that is perpendicular to and terminating at an interface between two materials is investigated using a linear fracture mechanics theory. The analysis is performed both for a crack penetrating the interface, growing straight ahead, and for a crack deflecting into the interface. The results from finite element calculations are compared with asymptotic solutions for infinitesimally small crack extensions. The solution is found to be accurate even for fairly large amounts of crack growth. Further, by comparing the crack tip driving force of the deflected crack with that of the penetrating crack, it is shown how to control the path of the crack by choosing the adhesion of the interface relative to the material toughness

Multipixel characterization of imaging CZT detectors for hard X-ray imaging and spectroscopy

We report our in-depth study of Cd-Zn-Te (CZT) crystals to determine an optimum pixel and guard band configuration for Hard X-ray imaging and spectroscopy. We tested 20x20x5mm crystals with 8x8 pixels on a 2.46mm pitch. We have studied different types of cathode / anode contacts and different pixel pad sizes. We present the measurements of leakage current as well as spectral response for each pixel. Our I-V measurement setup is custom designed to allow automated measurements of the I-V curves sequentially for all 64 pixels, whereas the radiation properties measurement setup allows for interchangeable crystals with the same XAIM3.2 ASIC readout from IDEAS. We have tested multiple crystals of each type, and each crystal in different positions to measure the variation between individual crystals and variation among the ASIC channels. We also compare the same crystals with and without a grounded guard band deposited on the crystal side walls vs. a floating guard band and compare results to simulations. This study was carried out to find the optimum CZT crystal configuration for prototype detectors for the proposed Black-Hole Finder mission, EXIST.Comment: To appears in the SPIE 2004 proceedings (5540: Hard X-ray and gamma-ray detector physics V

Management and outcome of patients with established coronary artery disease: the Euro Heart Survey on coronary revascularization

Aims The purpose of the Euro Heart Survey Programme of the European Society of Cardiology is to evaluate to which extent clinical practice endorses existing guidelines as well as to identify differences in population profiles, patient management, and outcome across Europe. The current survey focuses on the invasive diagnosis and treatment of patients with established coronary artery disease (CAD). Methods and results Between November 2001 and March 2002, 7769 consecutive patients undergoing invasive evaluation at 130 hospitals (31 countries) were screened for the presence of one or more coronary stenosis >50% in diameter. Patient demographics and comorbidity, clinical presentation, invasive parameters, treatment options, and procedural techniques were prospectively entered in an electronic database (550 variables+29 per diseased coronary segment). Major adverse cardiac events (MACE) were evaluated at 30 days and 1 year. Out of 5619 patients with angiographically proven coronary stenosis (72% of screened population), 53% presented with stable angina while ST elevation myocardial infarction (STEMI) was the indication for coronary angiography in 16% and non-ST segment elevation myocardial infarction or unstable angina in 30%. Only medical therapy was continued in 21%, whereas mechanical revascularization was performed in the remainder [percutaneous coronary intervention (PCI) in 58% and coronary artery bypass grafting (CABG) in 21%]. Patients referred for PCI were younger, were more active, had a lower risk profile, and had less comorbid conditions. CABG was performed mostly in patients with left main lesions (21%), two- (25%), or three-vessel disease (67%) with 4.1 diseased segments, on average. Single-vessel PCI was performed in 82% of patients with either single- (45%), two- (33%), or three-vessel disease (21%). Stents were used in 75% of attempted lesions, with a large variation between sites. Direct PCI for STEMI was performed in 410 cases, representing 7% of the entire workload in the participating catheterization laboratories. Time delay was within 90 min in 76% of direct PCI cases. In keeping with the recommendations of practice guidelines, the survey identified under-use of adjunctive medication (GP IIb/IIIa receptor blockers, statins, and angiotensin-converting enzyme-inhibitors). Mortality rates at 30 days and 1 year were low in all subgroups. MACE primarily consisted of repeat PCI (12%). Conclusion The current Euro Heart Survey on coronary revascularization was performed in the era of bare metal stenting and provides a global European picture of the invasive approach to patients with CAD. These data will serve as a benchmark for the future evaluation of the impact of drug-eluting stents on the practice of interventional cardiology and bypass surger

Progress in the Development of Mo-Au Transition-Edge Sensors for X-Ray Spectroscopy

X-ray microcalorimeters using transition-edge sensors (TES) show great promise for use in astronomical x-ray spectroscopy. We have obtained very high energy resolution (2.8 electronvolts at 1.5 kiloelectronvolts and 3.7 electronvolts at 3.3 kiloelectronvolts) in a large, isolated TES pixel using a Mo/Au proximity-effect bilayer on a silicon nitride membrane. We will discuss the performance and our characterization of that device. In order to be truly suitable for use behind an x-ray telescope, however, such devices need to be arrayed with a pixel size and focal-plane coverage commensurate with the telescope focal length and spatial resolution. Since this requires fitting the TES and its thermal link, a critical component of each calorimeter pixel, into a far more compact geometry than has previously been investigated, we must study the fundamental scaling laws in pixel optimization. We have designed a photolithography mask that will allow us to probe the range in thermal conductance that can be obtained by perforating the nitride membrane in a narrow perimeter around the sensor. This mask will also show the effects of reducing the TES area. Though we have not yet tested devices of the compact designs, we will present our progress in several of the key processing steps and discuss the parameter space of our intended investigations

Characteristics and outcomes of patients treated with apremilast in the real world: results from the APPRECIATE study

Background APPRECIATE is a multinational, observational, retrospective, cross‐sectional study in patients treated for psoriasis with apremilast, an oral phosphodiesterase 4 inhibitor. Objectives To describe the characteristics of patients with psoriasis treated with apremilast in the clinical setting, to evaluate real‐world outcomes of psoriasis treatment with apremilast and to better understand the perspectives of patients and physicians on treatment outcomes. Methods In six European countries, patients with chronic plaque psoriasis treated in clinical practice who could be contacted 6 (±1) months after apremilast initiation were enrolled. Patient characteristics, Dermatology Life Quality Index (DLQI) and Psoriasis Area and Severity Index (PASI) were obtained from medical records when available. Outcomes were evaluated using patient/physician questionnaires. Results In 480 patients at treatment initiation, mean [median; 95% confidence interval (CI)] PASI and DLQI scores were 12.5 (10.7; 11.6–13.4) and 13.4 (13.0; 11.4–14.2), respectively. At 6 (±1) months, 72.3% of patients (n = 347) continued apremilast treatment [discontinuations: lack of efficacy (13.5%), safety (11.7%), other (2.5%)]. In patients continuing treatment, 48.6% achieved a ≥75% reduction in PASI score; mean (95% CI) DLQI score was 5.7 (4.5–6.9), and mean (SD) Patient Benefit Index score was 2.8 (1.2). Physicians perceived clinical improvement in 75.6% of patients. Physicians’ perspective on overall success of apremilast in meeting expectations correlated with patients’ perception of treatment benefit (r = 0.691). Most commonly reported adverse events (>5% of patients) were diarrhoea, nausea and headache. Conclusions Patients in APPRECIATE reported high disease burden despite more moderate skin involvement than those who enrolled in clinical trials of apremilast. Findings from APPRECIATE demonstrate the real‐world value of apremilast for psoriasis treatment, as 7 of 10 patients continued therapy and showed notable improvement in disease severity and quality of life 6 (±1) months after apremilast initiation

POSYDON: A General-Purpose Population Synthesis Code with Detailed Binary-Evolution Simulations

Most massive stars are members of a binary or a higher-order stellar systems, where the presence of a binary companion can decisively alter their evolution via binary interactions. Interacting binaries are also important astrophysical laboratories for the study of compact objects. Binary population synthesis studies have been used extensively over the last two decades to interpret observations of compact-object binaries and to decipher the physical processes that lead to their formation. Here, we present POSYDON, a novel, binary population synthesis code that incorporates full stellar-structure and binary-evolution modeling, using the MESA code, throughout the whole evolution of the binaries. The use of POSYDON enables the self-consistent treatment of physical processes in stellar and binary evolution, including: realistic mass-transfer calculations and assessment of stability, internal angular-momentum transport and tides, stellar core sizes, mass-transfer rates and orbital periods. This paper describes the detailed methodology and implementation of POSYDON, including the assumed physics of stellar- and binary-evolution, the extensive grids of detailed single- and binary-star models, the post-processing, classification and interpolation methods we developed for use with the grids, and the treatment of evolutionary phases that are not based on pre-calculated grids. The first version of POSYDON targets binaries with massive primary stars (potential progenitors of neutron stars or black holes) at solar metallicity.Comment: 60 pages, 33 figures, 8 tables, referee's comments addressed. The code and the accompanying documentations and data products are available at https:\\posydon.or

Upregulation of MMP-13 and TIMP-1 expression in response to mechanical strain in MC3T3-E1 osteoblastic cells

<p>Abstract</p> <p>Background</p> <p>Mechanical strain plays a significant role in the regulation of bone matrix turnover, which is mediated in part by matrix metalloproteinase (MMP)-13 and tissue inhibitors of matrix metalloproteinase (TIMP)-1. However, little is known about the correlation between mechanical strain and osteoblastic cell activities, including extracellular matrix (ECM) metabolism. Herein, we determined the effect of different magnitudes of cyclic tensile strain (0%, 6%, 12%, and 18%) on MMP-13 and TIMP-1 mRNA and protein expression in MC3T3-E1 osteoblasts. Furthermore, we employed specific inhibitors to examine the role of distinct signal transduction pathways known to mediate cellular responses to mechanical strain.</p> <p>Results</p> <p>We identified a magnitude-dependent increase in MMP-13 and TIMP-1 mRNA and protein levels in response to mechanical strains corresponding to 6%, 12%, and 18% elongation. The strain-induced increases in MMP-13 and TIMP-1 mRNA expression were inhibited by PD098059 and cycloheximide, respectively.</p> <p>Conclusions</p> <p>Our results suggest a mechanism for the regulation of bone matrix metabolism mediated by the differential expression of MMP-13 and TIMP-1 in response to increasing magnitudes of mechanical strain.</p