The photoluminescence of intrinsic excitons in high purity AlxGa1−xAs layers is studied under interband excitation by circularly polarized light. To determine the nature of excitons, the luminescence depolarization effect in a transverse magnetic field (Hanle effect) is used. The experimental curves represent two contours. For the composition x = 0.15, additional peaks arranged symmetrically with respect to zero magnetic field are observed. It is shown that the luminescence is determined by excitons localized in a potential associated with alloy fluctuations. The appearance of the additional peaks is due to the crossing of J = 1 and J = 2 levels in a magnetic field. The exchange splitting of exciton levels, recombination and spin relaxation times are determined from a comparison between theoretical and experimental dependences.

Chronische Wunden der unteren Extremität erfordern immer eine konsequente Diagnostik zum Nachweis oder Ausschluß einer Durchblutungsstörung. Durch sie läßt sich eine arterielle, venöse oder gemischt arteriell-venöse Genese voneinander abgrenzen. Nach Debridement und resistenzgerechter Antibiose folgt bei arterieller Genese die endovaskuläre oder/und operative Revaskularisation. Konservative Maßnahmen sind nur bei mangelnder Revaskularisationsmöglichkeit indiziert. Die Sepsis und gescheiterte konservative oder operative Therapie zwingen zur Amputation. Venöse Ulcéra müssen chirurgisch saniert werden. Die crurale Lipofasziektomie stellt bei Manschettenulcera eine Alternative zur Amputation dar. Gemischt arteriell-venöse Ulcéra werden primär arteriell revaskularisiert und sekundär venös saniert. Zusätzliche plastische Deckungsverfahren können sich anschließen. Vorgestellt wird das Konzept an 206 gefäßchirurgisch versorgten Patienten (art. = 180, ven.= 18, gemischt=8).

Arteriosklerotische Prozesse im aortoiliakalen Bereich resultieren meist nicht in der extremitätenbedrohenden Ischämie, sind aber verantwortlich für Behinderungen durch Gesäß-, Oberschenkel- und Unterschenkelclaudicatio sowie für Impotenz. Zur Behandlung dieser Erkrankungen kommen mehrere Behandlungsregime in Betracht. Neben der alleinigen konservativen Therapie mit vasoaktiven Medikamenten und Gehtraining müssen bei stärkeren Beschwerden invasive Maßnahmen eingesetzt werden. Dies sind insbesondere gefäßchirurgische und katheterassistierte Verfahren, die alleine oder in Kombination einzeitig oder zweizeitig im Intervall eingesetzt werden können.

TRIUMF experiment E704 is a study of Charge Symmetry Breaking in the reaction np→dπ0. The observable is the forward–backward asymmetry in the centre-of-mass differential cross-section, predicted to be −0.0035 at 5 MeV above threshold. As a check on the understanding of certain systematic effects the reaction pp→dπ+, which cannot have an asymmetry, is measured also. Similarly, neutron–proton elastic scattering is used to verify spectrometer acceptance. We describe the beams, target, and detectors developed for this experiment.

Intestinal ischemia is still a challenge for clinicians and requires a close interdisciplinary cooperation between internist, surgeon and radiologist. In the East years the diagnosis and therapy, classically invasive and surgical, was supplemented by duplex ultrasound and percutaneous techniques like angioplasty and stenting.A 56 year-old man from Greece presented with epigastric pain, which was intensified by food ingestion. These symptoms were caused by a stenosis of the superior mesenteric artery, which was diagnosed by duplexsonography and angiography. No bloodflow was detected in the inferior mesenteric and the celiac artery Occlusion of one internal carotid artery made the patient a poor candidate for surgery. Therefore an interventional approach was chosen. A good result was achieved by angioplasty and stent implantation. On the day after the intervention oral food intake was possible without any pain. 18 months after the intervention the patient was free of abdominal symptoms.Therapy of mesenteric ischemia by percutaneous angioplasty and stenting is published only in case-reports and small series. Therefore the indication is mainly restricted to patients with a high risk for a surgical intervention.

This paper presents an investigation of the low-temperature band-edge photoluminescence (PL) of ZnO films prepared by spray pyrolysis. Annealing samples in forming gas modified the PL spectra and density of conduction electrons. Photoluminescence revealed a complicated multi-line structure. The origin of the observed near-UV lines was identified in terms of bound exciton complexes and the phonon replicas. In annealed high-conductivity samples this was the usual optical phonon replica with a period of 71.6 meV. In low-conductive as-grown films an oscillating structure with a period of 108 meV was revealed. This new structure was attributed to a two transverse optical phonon replica.

Intestinal ischemia is still a challenge for clinicians and requires a close interdisciplinary cooperation between internist, surgeon and radiologist. In the last years the diagnosis and therapy, classically invasive and surgical, was supplemented by duplex ultrasound and percutaneous techniques like angioplasty and stenting. A 56 year-old man from Greece presented with epigastric pain, which was intensified by food ingestion. These symptoms were caused by a stenosis of the superior mesenteric artery, which was diagnosed by duplex sonography and angiography. No blood flow was detected in the inferior mesenteric and the celiac artery. Occlusion of one internal carotid artery made the patient a poor candidate for surgery. Therefore an interventional approach was chosen. A good result was achieved by angioplasty and stent implantation. On the day after the intervention oral food intake was possible without any pain. 18 months after the intervention the patient was free of abdominal symptoms. Therapy of mesenteric ischemia by percutaneous angioplasty and stenting is published only in case-reports and small series. Therefore the indication is mainly restricted to patients with a high risk for a surgical intervention.

PURPOSE:To assess the efficiency and long-term patency of the Cragg EndoPro System I in patients with peripheral arterial aneurysms.MATERIALS AND METHODS:In 10 patients, 13 stent-grafts were used to treat 15 arterial aneurysms. Aneurysms were located in the common iliac (n = 4), superficial femoral (n = 4), popliteal (n = 3), and subclavian arteries (n = 2), and in a femoropopliteal bypass-graft (n = 2). Follow-up ranged between 2 and 46 months (mean, 36 months). Examination included clinical status, color-coded duplex sonography, computed tomography angiography, and intra-arterial digital subtraction angiography (DSA).RESULTS:Technical success was achieved in all patients. Primary patency was four of four in iliac vessels and three of nine in non-iliac vessels; secondary patency in noniliac vessels was four of nine. Repairs included one local lysis, four percutaneous transluminal angioplasties, one surgical thrombectomy, and one bypass surgery. Stent wire disintegration was detected in one of four iliac stent-grafts and in seven of nine noniliac stent-grafts. In noniliac grafts, significant stenoses occurred in three of nine; occlusion occurred in five of nine. One complication at the iliac level was a vessel wall penetration at the proximal stent edge, with development of a new aneurysmal formation. No late endoleaks were found.CONCLUSION:Exclusion of peripheral arterial aneurysms with stent-grafts is feasible. Long-term results are excellent in iliac vessels. Mechanical weakness of the stent assembly and frequent re-stenoses or occlusions are significant drawbacks in noniliac vessels with low patency rates.

Die intraoperative Kombinationstherapie definiert die endovaskuläre und rekonstruktive Behandlung komplexer Gefäßerkrankungen. Dabei hat sich die transprothetisch-transluminale Angioplastie einen besonderen Platz erobert. Die Offenheitsrate der femoralen Ballondilatation simultan zu Patchplastiken in der Leiste (n=58) betrug 70% nach 5 Jahren. Die transprothetische Angioplastie beim Cross-over-Bypass mit iliakalem Stent (n = 46) und jene beim femoro-poplitealen Bypass mit transprothetisch-poplitealer-cruraler Dilatation (n = 52) zeigten nach 5 Jahren Durchgängigkeitsraten von 83% bzw. 63%. 3 Pat. mit Aneurysma Typ IIb (nach Allenberg) erhielten eine aorto-uni-iliakale Stentprothese mit Cross-over-Bypass ohne Komplikationen nach 36, 16 und 2 Monaten.

Complex vascular disease requires combined, intraoperative endovascular and reconstructive therapy. Hereby, transprosthetic, transluminal angioplasty is particularly well suited for this purpose. The 5-year patency rate after combined inguinal patch plasty and femoral balloon dilation (n = 58) was 70%. The 5-year patency rates following transgraft angioplasty, with subsequent stent implantation and cross-over bypass (n = 46) and after transprosthetic, popliteal-crural dilation was 83% and 63%, respectively. Three patients with a type IIb (after Allenberg) aneurysm were treated with an aortoiliac stent prosthesis, combined with a cross-over bypass. The follow-up examinations at 2, 16 and 36 months were uneventful.

A liquid hydrogen target has been constructed for use in the measurement of low cross section reactions with a single detected charged particle in the final state, for example p(n, d)γ, n(p, d)π0 or p(p, d)π+. It uses thin plastic scintillation counters mounted close to the target container, in contact with a cold gas cell between the liquid hydrogen and an insulation vacuum. Pulse height information from these counters allows background events originating in most of the windows of the target assembly to be eliminated. The design and operational characteristics of the target are described.

Differential cross section measurements for the radiative capture reaction p(n,d)γ at 0°–3° laboratory angle and neutron energies of 360, 410 and 460 MeV (corresponding to photon lab energies of 182.5, 207.7 and 232.5 MeV for the inverse reaction) have been made using the TRIUMF medium resolution spectrometer. These data complement measured photo-disintegration differential cross sections at forward angles in this energy range and are the first capture cross sections at 0° above the pion-production energy threshold. The results are in qualitative agreement with three recent theoretical treatments of this reaction.