438 research outputs found

    Molecular dynamics of n-hexane: A quasi-elastic neutron scattering study on the bulk and spatially nanochannel-confined liquid

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    We present incoherent quasi-elastic neutron scattering measurements in a wavevector transfer range from 0.4 AA^{-1} to 1.6AA^{-1} on liquid n-hexane confined in cylindrical, parallel-aligned nanochannels of 6 nm mean diameter and 260 micrometer length in monolithic, mesoporous silicon. They are complemented with, and compared to, measurements on the bulk system in a temperature range from 50K to 250K. The time-of-flight spectra of the bulk liquid can be modeled by microscopic translational as well as fast localized rotational, thermally-excited, stochastic motions of the molecules. In the nano-confined state of the liquid, which was prepared by vapor condensation, we find two molecular populations with distinct dynamics, a fraction which is immobile on the time scale of 1ps to 100ps probed in our experiments and a second component with a self-diffusion dynamics slightly slower than observed for the bulk liquid. No hints of an anisotropy of the translational diffusion with regard to the orientation of the channels' long axes have been found. The immobile fraction amounts to about 5% at 250K, gradually increases upon cooling and exhibits an abrupt increase at 160K (20K below bulk crystallization), which indicates pore freezingComment: 10 pages, 7 figure

    Affiliation und Kontrolle in Partnerschaften

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    'Die von den beiden Autoren geplante Längsschnittstudie hat das Ziel, Unterschiede im interpersonalen Verhalten zufriedener und unzufriedener Partner zu identifizieren und den Einfluß dieses interpersonalen Verhaltens auf die Partnerschaftsstabilität und -zufriedenheit zu einem späteren Zeitpunkt zu untersuchen. Unterschiede vor allem im Ausmaß feindselig-kontrollierenden und freundlich-autonomiegewährendem Verhaltens werden erwartet.' (Autorenreferat

    The BCR-ABL1 Kinase Bypasses Selection for the Expression of a Pre–B Cell Receptor in Pre–B Acute Lymphoblastic Leukemia Cells

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    The BCR-ABL1 kinase expressed in acute lymphoblastic leukemia (ALL) drives malignant transformation of human pre–B cells. Comparing genome-wide gene expression profiles of BCR-ABL1+ pre–B ALL and normal bone marrow pre–B cells by serial analysis of gene expression, many genes involved in pre–B cell receptor signaling are silenced in the leukemia cells. Although normal pre–B cells are selected for the expression of a functional pre–B cell receptor, BCR-ABL1+ ALL cells mostly do not harbor a productively rearranged IGH allele. In these cases, we identified traces of secondary VH gene rearrangements, which may have rendered an initially productive VH region gene nonfunctional. Even BCR-ABL1+ ALL cells harboring a functional VH region gene are unresponsive to pre–B cell receptor engagement and exhibit autonomous oscillatory Ca2+ signaling activity. Conversely, leukemia subclones surviving inhibition of BCR-ABL1 by STI571 restore responsiveness to antigen receptor engagement and differentiate into immature B cells expressing immunoglobulin light chains. BCR-ABL1 kinase activity is linked to defective pre–B cell receptor signaling and the expression of a truncated isoform of the pre–B cell receptor–associated linker molecule SLP65. Also in primary leukemia cells, truncated SLP65 is expressed before but not after treatment of the patients with STI571. We conclude that inhibition of BCR-ABL1 reconstitutes selection for leukemia cells expressing a functional (pre–) B cell receptor

    Dynamics of conversion of supercurrents into normal currents, and vice versa

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    The generation and destruction of the supercurrent in a superconductor (S) between two resistive normal (N) current leads connected to a current source is computed from the source equation for the supercurrent density. This equation relates the gradient of the pair potential's phase to electron and hole wavepackets that create and destroy Cooper pairs in the N/S interfaces. Total Andreev reflection and supercurrent transmission of electrons and holes are coupled together by the phase rigidity of the non-bosonic Cooper-pair condensate. The calculations are illustrated by snapshots from a computer film.Comment: 8 pages, 1 figure, accepted by Phys. Rev.

    Radical surgical resection of advanced thymoma and thymic carcinoma infiltrating the heart or great vessels with cardiopulmonary bypass support

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    Background Radical surgical resection of advanced thymic tumors invading either the heart or great vessels facing towards the heart is uncommonly performed because of the potential morbidity and mortality. To achieve a complete tumor resection, the use of cardiolpulmonary bypass (CPB) support might be necessary. Methods Retrospective analysis of the results in six patients, who underwent radical tumor resection with CBP support. Results Mean age was 46 years (27 to 66 years) and five patients were male. Tumor infiltration of the heart or the great vessels was evident in all patients. Five patients underwent induction therapy. Two patients were operated in complete cardioplegic arrest (antegrade cerebral perfusion: n = 1). Arterial cannulation of the ascending aorta (n = 5) or the femoral artery (n = 1) and venous cannulation of the right atrium (n = 4) or the femoral vein (n = 2) were performed. Resection of the left brachiocephalic vein (n = 6), resection of the superior caval vein (n = 2), the ascending aorta (n = 1) and the complete aortic arch with outgoing branches (n = 1) were performed. A macroscopic complete resection (R0/R1) was achieved in five patients, whereas one patient was resected incompletely (R2). In-hospital mortality was 0 %. Three (50 %) patients needed operative revision (hematothorax: n = 2, chylothorax: n = 1). All patients had a complicated postoperative course and developed respiratory insufficiency. Conclusions Locally advanced thymoma/thymic carcinoma invading the heart or great vessels can be treated with radical surgical resection alongside with increased perioperative morbidity. The usage of CBP improves the chance of complete tumor resection in selected patients and might lead to a prolonged survival

    Minimally Invasive Vacuum-Assisted Closure Therapy With Instillation (Mini-VAC-Instill) for Pleural Empyema

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    Enthusiasm for minimally invasive thoracic surgery is increasing. Thoracoscopy plays a significant therapeutic role in the fibrinopurulent stage (stage II) of empyema, in which loculated fluid cannot often be adequately drained by chest tube alone. For some debilitated and septic patients, further procedures such as open-window thoracostomy (OWT) with daily wound care or vacuum-assisted closure (VAC) therapy are necessary. In the present article, we propose a new option of minimally invasive VAC therapy including a topical solution of the empyema without open-window thoracostomy (Mini-VAC-instill). Three patients who underwent surgery using this technique are also presented. The discussion is focused on the advantages and disadvantages of the approach

    Extrakorporale hydrostatische Hochdruckbehandlung als neues Verfahren zur Desinfektion infizierter Knochenpräparate

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    Background: Allogeneic bone transplantation is at risk of infection, and established disinfection methods typically compromise bone quality. High hydrostatic pressure (HHP) is well established for disinfection in food technology, and also it does protect biomechanical and biological properties of bone. This study is the first investigation of HHP regarding disinfection of bone biopsies. Materials and methods: Bone biopsies of 34 patients with chronic infections were subjected to HHP and assessed for persisting bacterial growth. In series 1, bone biopsies were proceeded directly to HHP (10 min; maximal pressure P-max 600 MPa). In series 2, HHP was applied after 5-day incubation in growth media (10 min or 2 x 30 min; P-max 600 MPa). Furthermore, HHP-induced changes of bacterial morphology on artificially infected bone samples were evaluated by scanning electron microscopy (SEM). Results: For series 1, 71% of the bone samples were sterilised by HHP (n = 17), compared to 38% of the untreated control samples, which were obtained during the same surgery (n = 8). For series 2, after prior incubation, HHP disinfected 7% of the bone specimens (n = 55), all control samples showed bacterial growth (n = 33). Destruction of cell wall integrity of Gram-negative strains was observed by SEM. Conclusion: The effectiveness of HHP for bone disinfection should be improved by optimising treatment parameters. Infections with barosensitive Gram-negative bacteria or yeast might represent possible clinical indications

    Evaluation of Surgical Therapy in Advanced Thymic Tumors

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    A complete resection of thymic tumors is known to be the most important prognostic factor, but it is often difficult to perform, especially in advanced stages. In this study, 73 patients with advanced thymic tumors of UICC stages III and IV who underwent radical resection were examined retrospectively. The primary endpoint was defined as the postoperative resection status. Secondary endpoints included postoperative morbidity, mortality, recurrence/progression-free, and overall survival. In total, 31.5% of patients were assigned to stage IIIa, 9.6% to stage IIIb, 47.9% to stage IVa, and 11% to stage IVb. In stages III a R0 resection was achieved in 53.3% of patients. In stages IV a R0/R1 resection was documented in 76.7% of patients. Surgical revision was necessary in 17.8% of patients. In-hospital mortality was 2.7%. Median recurrence/progression-free interval was 43 months (p = 0.19) with an overall survival of 79 months. The 5-year survival rate was 61.3%, respectively. Median survival after R2 resection was 25 months, significantly shorter than after R0 or R1 resection (115 months; p = 0.004). Advanced thymic tumors can be resected with an acceptable risk of complications and low mortality. In stage III as well as in stage IV the promising survival rates are dependent on the resection-status

    Adequate nephroprotection reduces renal complications after hyperthermic intrathoracic chemotherapy

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    Background and Objectives Hyperthermic intrathoracic chemotherapy (HITOC) is used for the treatment of malignant pleural tumors. Although HITOC proved to be safe, postoperative renal failure due to nephrotoxicity of intrapleural cisplatin remains a concern. Methods This single-center study was performed retrospectively in patients who underwent pleural tumor resection and HITOC between September 2008 and December 2018. Results A total of 84 patients (female n = 33; 39.3%) with malignant pleural tumors underwent surgical cytoreduction with subsequent HITOC (60 minutes; 42 degrees C). During the study period, we gradually increased the dosage of cisplatin (100-150 mg/m(2) BSA n = 36; 175 mg/m(2) BSA n = 2) and finally added doxorubicin (cisplatin 175 mg/m(2) BSA/doxorubicin 65 mg; n = 46). All patients had perioperative fluid balancing. The last 54 (64.3%) patients also received perioperative cytoprotection. Overall 29 patients (34.5%) experienced renal insufficiency. Despite higher cisplatin concentrations, patients with cytoprotection showed significantly lower postoperative serum creatinine levels after 1 week (P = .006) and at discharge (P = .020). Also, they showed less intermediate and severe renal insufficiencies (5.6% vs 13.3%). Conclusions Adequate perioperative fluid management and cytoprotection seem to be effective in protecting renal function. This allows the administration of higher intracavitary cisplatin doses without raising the rate of renal insufficiencies

    Complex pleural empyema can be safely treated with vacuum-assisted closure

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    <p>Abstract</p> <p>Objective</p> <p>For patients with postoperative pleural empyema, open window thoracostomy (OWT) is often necessary to prevent sepsis. Vacuum-assisted closure (VAC) is a well-known therapeutic option in wound treatment. The efficacy and safety of intrathoracal VAC therapy, especially in patients with pleural empyema with bronchial stump insufficiency or remain lung, has not yet been investigated.</p> <p>Methods</p> <p>Between October 2009 and July 2010, eight consecutive patients (mean age of 66.1 years) with multimorbidity received an OWT with VAC for the treatment of postoperative or recurrent pleural empyema. Two of them had a bronchial stump insufficiency (BPF).</p> <p>Results</p> <p>VAC therapy ensured local control of the empyema and control of sepsis. The continuous suction up to 125 mm Hg cleaned the wound and thoracic cavity and supported the rapid healing. Additionally, installation of a stable vacuum was possible in the two patients with BPF. The smaller bronchus stump fistula closed spontaneously due to the VAC therapy, but the larger remained open.</p> <p>The direct contact of the VAC sponge did not create any air leak or bleeding from the lung or the mediastinal structures. The VAC therapy allowed a better re-expansion of remaining lung.</p> <p>One patient died in the late postoperative period (day 47 p.o.) of multiorgan failure. In three cases, VAC therapy was continued in an outpatient service, and in four patients, the OWT was treated with conventional wound care. After a mean time of three months, the chest wall was closed in five of seven cases. However, two patients rejected the closure of the OWT. After a follow-up at 7.7 months, neither recurrent pleural empyema nor BPF was observed.</p> <p>Conclusion</p> <p>VAC therapy was effective and safe in the treatment of complicated pleural empyema. The presence of smaller bronchial stump fistula and of residual lung tissue are not a contraindication for VAC therapy.</p
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