625 research outputs found
Passive components used in power converters
In power converters, passive components play an important role, and have in general specific nature and properties. The goal of this tutorial is to give an overview, first on inductive components for power conversion, and second on dedicated power capacitors. In a third part, new components— supercapacitors—will be presented. Generally, inductors for power applications must be custom designed. In this tutorial, the most important effects encountered when realising inductive components will be presented in the first part, without entering into the detailed design of such components. For that purpose, the referenced documents that have served as a base for this tutorial must be consulted [1], [2], and mainly [3]. The second part of this tutorial (Capacitors used in power electronics) is dedicated to power capacitors. Unlike inductors, capacitors cannot be specifically designed, but must be selected from a manufacturer’s list of components. Here, the documentation corresponds to a subset of Ref. [4] that has been translated by Dr. Martin Veenstra. The third part of the tutorial (Supercapacitors and applications) presents supercapacitors, new components that have very high energy density and high power density. Modelling and design rules for several applications are presented. This part of the document uses as a base the study made by Dr. Philippe Barrade [5]. Finally, it must be noted that, even with a correct selection or design of passive elements, there can be parasitic effects caused by interactions between components of the same or different nature. As an example, by designing filters combining several passives like inductors and capacitors, the primary specification may be modified by the interaction of parasitics, typically a mutual coupling between the parasitic inductances of neighbouring capacitors. A good description of such effects can be found in Ref. [6]
Unsteady Heat-Flux Measurements of Second-Mode Instability Waves in a Hypersonic Boundary Layer
In this paper, we report on the application of the atomic layer thermopile (ALTP) heat-flux sensor to the measurement of laminar-to-turbulent transition in a hypersonic flat-plate boundary layer. The centerline of the flat-plate model was instrumented with a streamwise array of ALTP sensors, and the flat-plate model was exposed to a Mach 6 freestream over a range of unit Reynolds numbers. Here, we observed an unstable band of frequencies that are associated with second-mode instability waves in the laminar boundary layer that forms on the flat-plate surface. The measured frequencies, group velocities, phase speeds, and wavelengths of these instability waves are consistent with data previously reported in the literature. Heat flux time series, and the Morlet wavelet transforms of them, revealed the wave-packet nature of the second-mode instability waves. In addition, a laser-based radiative heating system was used to measure the frequency response functions (FRF) of the ALTP sensors used in the wind tunnel test. These measurements were used to assess the stability of the sensor FRFs over time and to correct spectral estimates for any attenuation caused by the finite sensor bandwidth
Unsteady Heat-Flux Measurements of Second-Mode Instability Waves in a Hypersonic Boundary Layer
In this paper we report on the application of the atomic layer thermopile (ALTP) heat- flux sensor to the measurement of laminar-to-turbulent transition in a hypersonic flat plate boundary layer. The centerline of the flat-plate model was instrumented with a streamwise array of ALTP sensors and the flat-plate model was exposed to a Mach 6 freestream over a range of unit Reynolds numbers. Here, we observed an unstable band of frequencies that are associated with second-mode instability waves in the laminar boundary layer that forms on the flat-plate surface. The measured frequencies, group velocities, phase speeds, and wavelengths of these instability waves are in agreement with data previously reported in the literature. Heat flux time series, and the Morlet-wavelet transforms of them, revealed the wave-packet nature of the second-mode instability waves. In addition, a laser-based radiative heating system was developed to measure the frequency response functions (FRF) of the ALTP sensors used in the wind tunnel test. These measurements were used to assess the stability of the sensor FRFs over time and to correct spectral estimates for any attenuation caused by the finite sensor bandwidth
Long-term course and outcome of obsessive-compulsive patientsafter cognitive-behavioral therapy in combination with eitherfluvoxamine or placebo: A 7-year follow-up of a randomized double-blind trial
Longitudinal studies with very long follow-up periods of patients with obsessive-compulsive disorder (OCD) who have received adequate treatment are rare. In the current study, 30 of 37 inpatients (81%) with severe OCD were followed up 6-8 years after treatment with cognitive-behavioral therapy (CBT) in combination with either fluvoxamine or placebo in a randomized design. The significant improvements (with large effectsizes) in obsessive-compulsive symptoms from pre- to post-treatment (41% reduction on the Y-BOCS) remained stable at follow-up (45 %). Responder rates, defined as ≥35% reduction on the Y-BOCS, were 67% and 60%, respectively. Depressive symptoms decreased significantly not only from pre- to post-treatment but also during follow-up. Re-hospitalization, which occurred in 11 patients (37 %), was associated with more severe depressive symptoms at pre-treatment and living without a partner. Full symptom remission at follow-up, defined as both Y-BOCS total score ≤ 7 and no longer meeting diagnostic criteria for OCD, was achieved by 8 patients (27 %). Patients without full remission at follow-up had a significantly longer history of OCD, assessed at pretreatment, compared to remitted patients. The shortterm treatment outcome had no predictive value for the long-term course. Throughout the naturalistic follow-up, nearly all patients (29 patients) received additional psychotherapy and/or medication. This might indicate that such chronic OCD patients usually need additional therapeutic support after effective inpatient treatment to maintain their improvements over long period
Bedeutung einer Veterinäranästhesistin oder eines Veterinäranästhesisten und einer optimalen Schmerztherapie aus Sicht von Hunde- und Katzenbesitzerinnen und -besitzer
In Switzerland, compared to the United Kingdom or the United States of America, fewer veterinary anaesthetists are employed in private practice, which raises the question about the reason. The present survey aimed at investigating the awareness of pet owners concerning the specialization of veterinary anaesthesia and the value they attribute to such a specialist. Also, estimation of pain in dogs and cats and the importance of its treatment from the point of view of the pet owners was analysed. Furthermore, the necessity of veterinary anaesthetists in private practice and the influencing factors were investigated. The survey was created on LimeSurvey, an online tool for questionnaires and sent to dog and cat owners of the small animal clinic of the University Hospital of Zurich. 317 fully completed questionnaires were evaluated. In general, pet owners appreciated the specialization of veterinary anaesthesiology. Great importance was attributed to the supervision of anaesthesia and analgesic therapy by a specialist. A preliminary talk with an anaesthetist would be appreciated. Owners would be willing to cover additional costs for a specialized anaesthetist, if recommended by the private veterinarian, and to bring their animal to the University Hospital, in case of an increased anaesthetic risk
Rapid and Continued T-Cell Differentiation into Long-term Effector and Memory Stem Cells in Vaccinated Melanoma Patients.
<b>Purpose:</b> Patients with cancer benefit increasingly from T-cell-based therapies, such as adoptive T-cell transfer, checkpoint blockade, or vaccination. We have previously shown that serial vaccinations with Melan-A <sup>MART-1</sup> <sub>26-35</sub> peptide, CpG-B, and incomplete Freund adjuvant (IFA) generated robust tumor-specific CD8 T-cell responses in patients with melanoma. Here, we describe the detailed kinetics of early- and long-term establishment of T-cell frequency, differentiation (into memory and effector cells), polyfunctionality, and clonotype repertoire induced by vaccination. <b>Experimental Design:</b> Twenty-nine patients with melanoma were treated with multiple monthly subcutaneous vaccinations consisting of CpG-B, and either the native/EAA ( <i>n</i> = 13) or the analogue/ELA ( <i>n</i> = 16) Melan-A <sup>MART-1</sup> <sub>26-35</sub> peptide emulsified in IFA. Phenotypes and functionality of circulating Melan-A-specific CD8 T cells were assessed directly <i>ex vivo</i> by multiparameter flow cytometry, and TCR clonotypes were determined <i>ex vivo</i> by mRNA transcript analyses of individually sorted cells. <b>Results:</b> Our results highlight the determining impact of the initial vaccine injections on the rapid and strong induction of differentiated effector T cells in both patient cohorts. Moreover, long-term polyfunctional effector T-cell responses were associated with expansion of stem cell-like memory T cells over time along vaccination. Dominant TCR clonotypes emerged early and persisted throughout the entire period of observation. Interestingly, one highly dominant clonotype was found shared between memory and effector subsets. <b>Conclusions:</b> Peptide/CpG-B/IFA vaccination induced powerful long-term T-cell responses with robust effector cells and stem cell-like memory cells. These results support the further development of CpG-B-based cancer vaccines, either alone or as specific component of combination therapies. <i>Clin Cancer Res; 23(13); 3285-96. ©2016 AACR</i>
TIE-2-expressing monocytes are lymphangiogenic and associate specifically with lymphatics of human breast cancer.
In experimental mouse models of cancer, increasingly compelling evidence point toward a contribution of tumor associated macrophages (TAM) to tumor lymphangiogenesis. Corresponding experimental observations in human cancer remain scarce although lymphatic metastasis is widely recognized as a predominant route for tumor spread. We previously showed that, in malignant tumors of untreated breast cancer (BC) patients, TIE-2-expressing monocytes (TEM) are highly proangiogenic immunosuppressive cells and that TIE-2 and VEGFR signaling pathways drive TEM immunosuppressive function. We report here that, in human BC, TEM express the canonical lymphatic markers LYVE-1, Podoplanin, VEGFR-3 and PROX-1. Critically, both TEM acquisition of lymphatic markers and insertion into lymphatic vessels were observed in tumors but not in adjacent non-neoplastic tissues, suggesting that the tumor microenvironment shapes both TEM phenotype and spatial distribution. We assessed the lymphangiogenic activity of TEM isolated from dissociated primary breast tumors in vitro and in vivo using endothelial cells (EC) sprouting assay and corneal vascularization assay, respectively. We show that, in addition to their known hemangiogenic function, TEM isolated from breast tumor display a lymphangiogenic activity. Importantly, TIE-2 and VEGFR pathways display variable contributions to TEM angiogenic and lymphangiogenic activities across BC patients; however, combination of TIE-2 and VEGFR kinase inhibitors abrogated these activities and overcame inter-patient variability. These results highlight the direct contribution of tumor TEM to the breast tumor lymphatic network and suggest a combined use of TIE-2 and VEGFR kinase inhibitors as a therapeutic approach to block hem- and lymphangiogenesis in BC
NASA Langley Experimental Aerothermodynamic Contributions to Slender and Winged Hypersonic Vehicles
No abstract availabl
Vaccination with LAG-3Ig (IMP321) and Peptides Induces Specific CD4 and CD8 T-Cell Responses in Metastatic Melanoma Patients-Report of a Phase I/IIa Clinical Trial.
PURPOSE: Cancer vaccines aim to generate and maintain antitumor immune responses. We designed a phase I/IIa clinical trial to test a vaccine formulation composed of Montanide ISA-51 (Incomplete Freund's Adjuvant), LAG-3Ig (IMP321, a non-Toll like Receptor agonist with adjuvant properties), and five synthetic peptides derived from tumor-associated antigens (four short 9/10-mers targeting CD8 T-cells, and one longer 15-mer targeting CD4 T-cells). Primary endpoints were safety and T-cell responses.
EXPERIMENTAL DESIGN: Sixteen metastatic melanoma patients received serial vaccinations. Up to nine injections were subcutaneously administered in three cycles, each with three vaccinations every 3 weeks, with 6 to 14 weeks interval between cycles. Blood samples were collected at baseline, 1-week after the third, sixth and ninth vaccination, and 6 months after the last vaccination. Circulating T-cells were monitored by tetramer staining directly ex vivo, and by combinatorial tetramer and cytokine staining on in vitro stimulated cells.
RESULTS: Side effects were mild to moderate, comparable to vaccines with Montanide alone. Specific CD8 T-cell responses to at least one peptide formulated in the vaccine preparation were found in 13 of 16 patients. However, two of the four short peptides of the vaccine formulation did not elicit CD8 T-cell responses. Specific CD4 T-cell responses were found in all 16 patients.
CONCLUSIONS: We conclude that vaccination with IMP321 is a promising and safe strategy for inducing sustained immune responses, encouraging further development for cancer vaccines as components of combination therapies. Clin Cancer Res; 22(6); 1330-40. ©2015 AACR
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