Unbound states in quantum heterostructures

We report in this review on the electronic continuum states of semiconductor Quantum Wells and Quantum Dots and highlight the decisive part played by the virtual bound states in the optical properties of these structures. The two particles continuum states of Quantum Dots control the decoherence of the excited electron – hole states. The part played by Auger scattering in Quantum Dots is also discussed

Die Wertigkeit der hepatobiliären Funktionsszintigraphie mit 99mTc-Diaethyl-IDA

99mTc-DAIDA ist anderen cholotropen Radiopharmazeutika überlegen. Wie radiochromatographische Untersuchungen mit verschiedenen Systemen zeigten, wird es unverändert von den Leberparenchymzellen als Anion in die Galle sezcrniert.Nach Prüfung an einem hepatogastroenterologisch selektierten Krankengut (n = 45) ergaben sich bei lebergesunden Probanden für die hepatobiliären Funktionsparameter Tmax. T/2, Gallenblasen- und Darmerscheinungszeit folgende Werte (x ± s): 15,5 ± 5,2 min), 30,8 ± 8,2 min, 13,5 ± 6,1 min, und 22,0 ± 10,8 min. Die nach Vergleich verschiedener Bestimmungsregionen und Berechnungsarten ermittelte Clearance betrug in dieser Gruppe 323,8 ± 145,8 ml/min x 1,73 m2 (x ± s); die mit der hepatobiliären Elimination konkurrierende renale Ausscheidung während 5 1 min p. i. belief sich auf 5,15% der injizierten Gesamtaktivität.Die Werte der einzelnen Zeitparameter wie auch der Anteil der Nieren bei der 99mTc-DAIDA-Ausscheidung erhöhten sich in der Gruppe der Patienten mit intrahepatischem Ikterus deutlich, in der Gruppe mit sonstigen Leberzellschäden nur geringfügig. Bei Patienten mit extrahepatischem Ikterus war eine Bestimmung der verschiedenen Leberfunktionsgrößen nicht möglich. Aufgrund der großen Variationsbreite innerhalb der einzelnen Gruppen blieben diese Parameter im Einzelfall ohne diagnostische Relevanz.Die hepatobiliäre Sequenzszintigraphie mit 99mTc-DAIDA scheint ihr Indikationsgebiet in der funktionsmorphologischen Diagnostik zu finden.</jats:p

Mechanical Thrombectomy in Patients with Acute Ischemic Stroke and Concomitant Intracranial Hemorrhage

Abstract Purpose Intravenous thrombolysis and mechanical thrombectomy (MT) are standard of care in patients with acute ischemic stroke due to large vessel occlusion. Data on MT in patients with intracranial hemorrhage prior to intervention is limited to anecdotal reports, as these patients were excluded from thrombectomy trials. Methods We analyzed patients from an observational multicenter cohort with acute ischemic stroke and endovascular treatment, the German Stroke Registry—Endovascular Treatment trial, with intracranial hemorrhage before MT. Baseline characteristics, procedural parameters and functional outcome at 90 days were analyzed and compared to a propensity score matched cohort. Results Out of 6635 patients, we identified 32 patients (0.5%) with acute ischemic stroke due to large vessel occlusion and preinterventional intracranial hemorrhage who underwent MT. Risk factors of intracranial hemorrhage were head trauma, oral anticoagulation and intravenous thrombolysis. Overall mortality was high (50%) but among patients with a premorbid modified Rankin scale (mRS) of 0–2 (n = 15), good clinical outcome (mRS 0–2) at 90 days was achieved in 40% of patients. Periprocedural and outcome results did not differ between patients with and without preinterventional intracranial hemorrhage. Conclusion Preinterventional intracranial hemorrhage in acute ischemic stroke patients with large vessel occlusion is rare. The use of MT is technically feasible and a substantial number of patients achieve good clinical outcome, indicating that MT should not be withheld in patients with preinterventional intracranial hemorrhage. </jats:sec

Endovascular Treatment for Acute Stroke in Cerebral Amyloid Angiopathy

Background and Purpose: We aimed to compare outcome of endovascular thrombectomy in acute ischemic stroke in patients with and without cerebral amyloid angiopathy (CAA). Methods: We included patients with and without possible or probable CAA based on the modified Boston criteria from an observational multicenter cohort of patients with acute ischemic stroke and endovascular thrombectomy, the German Stroke Registry Endovascular Treatment trial. We analyzed baseline characteristics, procedural parameters, and functional outcome after 90 days. Results: Twenty-eight (17.3%) of 162 acute ischemic stroke patients were diagnosed with CAA based on iron-sensitive magnetic resonance imaging performed before endovascular thrombectomy. CAA patients were less likely to have a good 90-day outcome (14.3 versus 37.8%). National Institutes of Health Stroke Scale score (adjusted odds ratio, 0.88; P &lt;0.001), successful recanalization (adjusted odds ratio 6.82; P =0.005), and CAA (adjusted odds ratio 0.28; P =0.049) were independent outcome predictors. Intravenous thrombolysis was associated with an increased rate of good outcome (36.3% versus 0%, P =0.031) in CAA. Conclusions: Endovascular thrombectomy with or without thrombolysis appears beneficial in acute ischemic stroke patients with possible or probable CAA, but is associated with a worse functional outcome. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03356392. </jats:sec

Machine Learning-Based Identification of Target Groups for Thrombectomy in Acute Stroke

Whether endovascular thrombectomy (EVT) improves functional outcome in patients with large-vessel occlusion (LVO) stroke that do not comply with inclusion criteria of randomized controlled trials (RCTs) but that are considered for EVT in clinical practice is uncertain. We aimed to systematically identify patients with LVO stroke underrepresented in RCTs who might benefit from EVT. Following the premises that (i) patients without reperfusion after EVT represent a non-treated control group and (ii) the level of reperfusion affects outcome in patients with benefit from EVT but not in patients without treatment benefit, we systematically assessed the importance of reperfusion level on functional outcome prediction using machine learning in patients with LVO stroke treated with EVT in clinical practice (N=5235, German-Stroke-Registry) and in patients treated with EVT or best medical management from RCTs (N=1488, Virtual-International-Stroke-Trials-Archive). The importance of reperfusion level on outcome prediction in an RCT-like real-world cohort equaled the importance of EVT treatment allocation for outcome prediction in RCT data and was higher compared to an unselected real-world population. The importance of reperfusion level was magnified in patient groups underrepresented in RCTs, including patients with lower NIHSS scores (0-10), M2 occlusions, and lower ASPECTS (0-5 and 6-8). Reperfusion level was equally important in patients with vertebrobasilar as with anterior LVO stroke. The importance of reperfusion level for outcome prediction identifies patient target groups who likely benefit from EVT, including vertebrobasilar stroke patients and among patients underrepresented in RCT patients with low NIHSS scores, low ASPECTS, and M2 occlusions