544 research outputs found
Random walks of molecular motors arising from diffusional encounters with immobilized filaments
Movements of molecular motors on cytoskeletal filaments are described by
directed walks on a line. Detachment from this line is allowed to occur with a
small probability. Motion in the surrounding fluid is described by symmetric
random walks. Effects of detachment and reattachment are calculated by an
analytical solution of the master equation in two and three dimensions. Results
are obtained for the fraction of bound motors, their average velocity and
displacement. The diffusion coefficient parallel to the filament becomes
anomalously large since detachment and subsequent reattachment, in the presence
of directed motion of the bound motors, leads to a broadening of the density
distribution.
The occurrence of protofilaments on a microtubule is modeled by internal
states of the binding sites. After a transient time all protofilaments become
equally populated.Comment: 20 pages Phys Rev E format + 11 figure
Behavioral and neurophysiological effects of morphological awareness training on spelling and reading
Behavioral and neurophysiological effects of a computer-aided morphological training protocol were examined in German-speaking children from Grades 3 to 9. Study 1 compared morphological awareness, reading, and spelling skills of 34 trained children with an untrained control group of 34 children matched for age, sex, and intelligence. All participants in the training group showed increases in morphological awareness, but only students from secondary school improved significantly in reading and spelling competences. In Study 2, a subsample of 8 trained children with poor spelling and reading abilities and 10 untrained children with higher language competencies underwent an electroencephalography testing involving three different language tasks. The training resulted in decreased theta-activity and increased activity in lower (7-10Hz) and upper alpha (10-13Hz). These findings reflect more effortful and attention-demanding processing after the training and suggest that children with poor spelling and reading abilities use the acquired morphological knowledge in terms of a compensatory strateg
T lymphocytes from patients with primary biliary cirrhosis produce reduced amounts of lymphotoxin, tumor necrosis factor and interferon-gamma upon mitogen stimulation
Primary biliary cirrhosis (PBC) is considered an autoimmune disease characterized by destruction of small intrahepatic
bile ducts by lymphocytes. Altered functions of these lymphocytes might reflect an abnormal immune response leading
to tissue damage. We investigated lymphokine secretion by mitogen-stimulated T lymphocytes from the liver biopsies
of patients with PBC and for comparison also peripheral blood. In PBC, diminished synthesis of lymphotoxin (TNFP),
tumor necrosis factor (TNFa) and interferon-y (IFIVy) was found both in T-cell lines from liver tissue and in peripheral
blood. The reduction was most prominent for TNFP in early histological stages of PBC, and appeared to be a stable
phenomenon when T cells were tested after long-term tissue culture. Analysis of mRNA levels indicates a possible link
between reduced TNFP production and a defect in interleukin-2 transcription. The data suggest that diminished
lymphokine production in patients with PBC may play ;In important role in the immanopathogenesis of this disease
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Long-Term Experience of Chemoradiotherapy Combined with Deep Regional Hyperthermia for Organ Preservation in High-Risk Bladder Cancer (Ta, Tis, T1, T2).
BackgroundThe aim of this study was to evaluate the efficacy and safety of chemoradiotherapy (RCT) combined with regional deep hyperthermia (RHT) of high-risk bladder cancer after transurethral resection of bladder tumor (TUR-BT).Materials and methodsBetween 1982 and 2016, 369 patients with pTa, pTis, pT1, and pT2 cN0-1 cM0 bladder cancer were treated with a multimodal treatment after TUR-BT. All patients received radiotherapy (RT) of the bladder and regional lymph nodes. RCT was administered to 215 patients, RCT + RHT was administered to 79 patients, and RT was used in 75 patients. Treatment response was evaluated 4-6 weeks after treatment with TUR-BT.ResultsComplete response (CR) overall was 83% (290/351), and in treatment groups was RT 68% (45/66), RCT 86% (178/208), and RCT + RHT 87% (67/77). CR was significantly improved by concurrent RCT compared with RT (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.05-5.12; p = .037), less influenced by hyperthermia (OR, 2.56; 95% CI, 0.88-8.00; p = .092). Overall survival (OS) after RCT was superior to RT (hazard ratio [HR], 0.7; 95% CI, 0.50-0.99; p = .045). Five-year OS from unadjusted Kaplan-Meier estimates was RCT 64% versus RT 45%. Additional RHT increased 5-year OS to 87% (HR, 0.32; 95% CI, 0.18-0.58; p = .0001). RCT + RHT compared with RCT showed a significantly better bladder-preservation rate (HR, 0.13; 95% CI, 0.03-0.56; p = .006). Median follow-up was 71 months. The median number of RHT sessions was five.ConclusionThe multimodal treatment consisted of a maximal TUR-BT followed by RT; concomitant platinum-based chemotherapy combined with RHT in patients with high-grade bladder cancer improves local control, bladder-preservation rate, and OS. It offers a promising alternative to surgical therapies like radical cystectomy.Implications for practiceRadical cystectomy with appropriate lymph node dissection has long represented the standard of care for muscle-invasive bladder cancer in medically fit patients, despite many centers reporting excellent long-term results for bladder preserving strategies. This retrospective analysis compares different therapeutic modalities in bladder-preservation therapy. The results of this study show that multimodal treatment consisting of maximal transurethral resection of bladder tumor followed by radiotherapy, concomitant platinum-based chemotherapy combined with regional deep hyperthermia in patients with Ta, Tis, T1-2 bladder carcinomas improves local control, bladder-preservation rate, and survival. More importantly, these findings offer a promising alternative to surgical therapies like radical cystectomy. The authors hope that, in the future, closer collaboration between urologists and radiotherapists will further improve treatments and therapies for the benefit of patients
Repair of stent graft-induced retrograde type A aortic dissection using the E-vita open prosthesis†
OBJECTIVES Stent graft-induced retrograde type A dissection is a life-threatening complication after endovascular treatment of acute aortic type B dissections. METHODS From August 2005 to February 2011, retrograde aortic dissection occurred in 4 of 29 patients (13.8%) undergoing thoracic endovascular aortic repair (TEVAR) for acute complicated aortic type B dissection. Three patients underwent emergent surgical conversion immediately after TEVAR. The operative strategy was a combined surgical and endovascular approach (frozen elephant trunk technique) using a specially designed hybrid prosthesis (Jotec E-vita open). All operations were performed under moderate hypothermia (25-28°C) and selective bilateral antegrade cerebral perfusion. The mean duration of circulatory arrest was 56±7min. Operative data and the outcome of surgery were analysed retrospectively. Data were analysed retrospectively in the limited number of patients. RESULTS All patients survived the surgical procedure. No stroke, paraplegia, renal failure or other major complications occurred. Postoperative CT scans revealed perigraft thrombus formation and stable aortic dimensions in all patients after 6 months. In one patient, the retrograde dissection remained primarily undetected and untreated. The patient died suddenly, with no clinical signs, within 7 days after stent graft implantation. Autopsy revealed cardiac tamponade due to retrograde type A aortic dissection. CONCLUSIONS Retrograde aortic dissection type A is a serious complication of thoracic endovascular repair of acute aortic type B dissection. Despite the small number of patients investigated in this study, the frozen elephant trunk technique appears to be a feasible bail-out strategy for the treatment of these acute aortic event
Self-trapping in an array of coupled 1D Bose gases
We study the transverse expansion of arrays of ultracold Rb atoms
weakly confined in tubes created by a 2D optical lattice, and observe that
transverse expansion is delayed because of mutual atom interactions. A
mean-field model of a coupled array shows that atoms become localized within a
roughly square fort-like self-trapping barrier with time-evolving edges. But
the observed dynamics is poorly described by the mean-field model. Theoretical
introduction of random phase fluctuations among tubes improves the agreement
with experiment, but does not correctly predict the density at which the atoms
start to expand with larger lattice depths. Our results suggest a new type of
self-trapping, where quantum correlations suppress tunneling even when there
are no density gradients
Die Europäische sozio-ökonomische Klassifikation (ESeC): zukünftiges Standardinstrument für internationale Vergleiche im Bereich sozialer Ungleichheit
"Die europäische und auch bundesdeutsche Ungleichheitsforschung steht aus guten Gründen in der Tradition, in erster Linie kategoriale Konzepte zur Messung sozialer Ungleichheit zu verwenden (z.B. Klassen, Schichten, Milieus, Berufsgruppierungen). Während sich im nationalen Kontext einige Deutschland-spezifische Konzepte etablieren konnten (z.B. Stellung im Beruf/ Betrieb), ist es in internationalen Untersuchungen vor allem das Erikson-Goldthorpe-Klassenschema (EGP), das eine vergleichbare Messung von sozialer Ungleichheit herstellen kann. Das Problem des EGP-Klassenschemas besteht jedoch in der zum Teil mittlerweile veralteten Klasseneinteilung und der je nach Land unterschiedlichen Generierung des Klassenschemas. In Deutschland beispielsweise werden Informationen (u.a. Stellung im Beruf/ Betrieb) zur Generierung dieses Klassenschemas herangezogen, die es in dieser Detailliertheit in vielen anderen Ländern nicht gibt. Ziel der neuen Europäischen Sozio-ökonomischen Klassifikation (ESeC) ist es, die Vergleichbarkeit sozialer Disparitäten in Europa deutlich zu verbessern. Die Klassifikation stellt konzeptionell eine Weiterentwicklung des bisherigen EGP-Klassenschemas dar und garantiert eine einheitliche Messung der sozio-ökonomischen Positionen von Individuen und Haushalten in Europa. Die neue Klassifikation wird aller Voraussicht nach in die amtlichen Statistiken aller 25 EU-Staaten eingehen (für Deutschland z.B. in den Mikrozensus, die Arbeitskräfteerhebung, EU-SILC) und soll eine möglichst große Verbreitung in europaweiten und nationalen wissenschaftlichen Umfragen finden. Sie ermöglicht somit einen genaueren deskriptiven Vergleich zwischen den EU-Ländern und eröffnet insbesondere für Wissenschaftler/innen eine Vielzahl von Möglichkeiten für Zusammenhangsanalysen in den verschiedensten Bereichen der Ungleichheitsforschung. Entwickelt wird diese neue Klassifikation als EU-Projekt von einem Konsortium, in dem international erfahrene Ungleichheitsforscher unter der Leitung von David Rose vereinigt sind ( http://www.iser.essex.ac.uk/esec ). Im Rahmen der Sektionssitzung zu aktuellen Forschungsprojekten möchten die Verfasser als deutsche Vertreter/innen des Konsortiums den Prototypen dieser neuen Klassifikation vorstellen und die Klassifikation einer kritischen Diskussion der Sektionsmitglieder aussetzen. Der Vortrag soll sich in fünf Teile aufgliedern: Im ersten Schritt möchten sie die konzeptionellen Grundlagen der Klassifikation erläutern und dabei vor allem die Weiterentwicklungen im Vergleich zu dem EGP-Klassenschema hervorheben. Es folgt zweitens eine kurze Darstellung der Operationalisierung von ESeC. Als Schwerpunkt werden drittens mehrere Analysen zur Kriteriums- und Konstruktvalidität des neuen Klassenschemas für Deutschland vorgestellt, basierend auf Daten des Bundesinstituts für Berufsbildung (BIBB-IAB-Erhebung 1998/1999) und des sozio-ökonomischen Panels. Viertens erfolgt ein Vergleich der Performanz der neuen Klassifikation zu bestehenden nationalen und internationalen Konzepten zur Messung sozialer Ungleichheit. Eine ausführliche Diskussion über die Vor- und Nachteile der neuen Klassifikation für Analysen im nationalen und internationalen Kontext beschließen die Vorstellung der neuen Klassifikation." (Autorenreferat
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