709 research outputs found
An experimental investigation of the propulsive thrust of oscillating foils of different planforms
A second design loop in the development of the computer controlled oscillating motion apparatus was completed as a part of this research. Specifically, work was concentrated in two areas: first, modifications to the existing motion control software with the aim to produce a continuous sinusoidal motion, and second, design of a dynamometer to measure more accurately the thrust developed by the oscillating foil. -- Bench tests conducted with the changes in the motion control indicated that the limitations to produce true sinusoidal oscillatory motion were due to the oscillating apparatus drive system. A single degree of freedom dynamometer consisted of two flexible vertical sheets to which a rigid plate was connected forming a U frame. This design allowed for sensitivity in the fore and aft direction, but was very rigid in the transverse direction. The oscillating apparatus was supported by the frame, and thrust or drag forces developed by the oscillating foil were transmitted through this frame to the load cell. -- An experimental study to measure developed thrust from a series of rigid foils subjected to unsteady, oscillatory motion has been conducted in the towing tank at Memorial University of Newfoundland. The foils tested consisted of a rectangular planform, a straight tapered and swept back planform, as well as the planform with curved leading edge, similar to the flukes of a fin whale. The foils had the same aspect ratio of 6. Two foils were fabricated out of brass, and another was made out of wood. The brass foils had a span of 200 mm, while the wooden foil had a span of 400 mm. In the experiment the heave amplitude to chord ratio was large (of order 1) and the pitch amplitudes tested were :6, 13, 17.5 and 21 deg. The pitching axis position was fixed at chord/2, and pitch led heave by 90 deg. -- Results of developed thrust from different planforms are presented and examined with respect to four areas of interest: large amplitude motion, effects of different planforms on developed thrust, foil performance at large angles of attack, and a comparison of an existing 3D unsteady flow panel code to predict developed thrust with the experimental results. -- Comparison of experimental results with the panel method showed that for small reduced frequencies and angles of attack, agreement in the magnitude of the thrust coefficient was good. At large reduced frequencies and angles of attack results from the panel method underpredicted the developed thrust. This discrepancy in results was due to separation and dynamic stall which occurred in the range of 33 to 40 deg. angle of attack. The combination of a leading edge sweep and taper of the foil's planform has a marked difference in developed thrust compared to the foil with a straight leading edge. This was due to different stall behaviour over foils with leading edge sweep compared to the stall of foils with a straight leading edge
Anatomical success rate of pars plana vitrectomy for treatment of complex rhegmatogenous retinal detachment
BACKGROUND: Pars plana vitrectomy (PPV) is preferred surgical procedure for the management of complex rhegmatogenous retinal detachment (RRD). The purpose of this study was to evaluate the anatomical results of primary PPV for the treatment of primary complex RRD and to determine the influence of lens status, tamponading agent, preoperative proliferative vitreoretinopathy (PVR) and axial length (AL) of the eye upon the anatomical outcome. METHODS: A retrospective consecutive chart analysis was performed on 117 eyes from 117 patients with complex RRD managed with PPV. Fifty-nine eyes were phakic and 58 pseudophakic eyes. All patients had a minimum follow-up period of 12 months. Eyes were classified into groups using independent variables (first classification based upon lens status and tamponade used, second classification based upon lens and PVR status and third classification based upon AL of the eye). The groups were compared for anatomical outcomes (dependent variables) using nonparametric- or, in case of normally distributed data, parametric- statistical tests. RESULTS: Retinal reattachment rate in phakic eyes was 94.9% compared to 93.1% in pseudophakic, with no statistically significant difference between the two. The overall retinal reattachment rate with single surgery was 94.0%. Final reattachment rate was 97.4%. In case of established PVR >/= C1, the reattachment rate was not statistically different (92.6%) from eyes with no PVR (91.1%) irrespective of lens status. A statistically significant difference was found between redetachment rates only between phakic eyes with gas tamponade compared to silicon oil (SO) (p = 0.001). Reattachment rate proved to be similar in both AL groups ( 24 mm). CONCLUSIONS: High anatomical success rate of primary vitrectomy for complex RRD with either gas or SO tamponade was achieved in phakic as well as pseudophakic eyes irrespective of AL of the eye
Novel regulatory therapies for prevention of Graft-versus-host disease
Graft-versus-host disease is one of the major transplant-related complications in allogeneic hematopoietic stem cell transplantation. Continued efforts have been made to prevent the occurrence of severe graft-versus-host disease by eliminating or suppressing donor-derived effector T cells. Conventional immunosuppression does not adequately prevent graft-versus-host disease, especially in mismatched transplants. Unfortunately, elimination of donor-derived T cells impairs stem cell engraftment, and delays immunologic reconstitution, rendering the recipient susceptible to post-transplant infections and disease relapse, with potentially lethal consequences. In this review, we discuss the role of dynamic immune regulation in controlling graft-versus-host disease, and how cell-based therapies are being developed using regulatory T cells and other tolerogenic cells for the prevention and treatment of graft-versus-host disease. In addition, advances in the design of cytoreductive conditioning regimens to selectively target graft-versus-host disease-inducing donor-derived T cells that have improved the safety of allogeneic stem cell transplantation are reviewed. Finally, we discuss advances in our understanding of the tolerogenic facilitating cell population, a phenotypically and functionally distinct population of bone marrow-derived cells which promote hematopoietic stem cell engraftment while reducing the risk of graft-versus-host disease
“BIG DATA” EN PROSPECCIÓN ARQUEOLÓGICA DEL PAISAJE
[EN] While traditionally archaeological research has mainly been focused on individual cultural heritage monuments or distinct archaeological sites, the Austrian based Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology goes beyond the limitations of discrete sites in order to understand their archaeological context. This is achieved by investigating the space in-between the sites, studying entire archaeological landscapes from the level of individual postholes to the mapping of numerous square kilometres. This large-scale, high-resolution, multi-method prospection approach leads to enormous digital datasets counting many terabytes of data that until recently were technically not manageable. Novel programs and methods of data management had to be developed for data acquisition, processing and archaeological interpretation, in order to permit the extraction of the desired information from the very big amount of data. The analysis of the generated datasets is conducted with the help of semi-automatic algorithms within complex three-, or even four-dimensional geographical information systems. The outcome of landscape archaeological prospection surveys is visually communicated to the scientific community as well as to the general public and stakeholders. In many cases, a visualization of the scientific result and archaeological interpretations can be a powerful and suitable tool to illustrate and communicate even complex contexts to a wide audience. This paper briefly presents the great potential offered by a combination of large-scale non-invasive archaeological prospection methods and standardized workflows for the integration of big data, its interpretation and visualization. The proposed approach provides a context for buried archaeology across entire archaeological landscapes, changing our understanding of known monuments. We address the overcome and remaining challenges with the help of examples taken from outstanding landscape archaeological prospection case studies.[ES] Aunque tradicionalmente la investigación arqueológica ha estado fundamentalmente centrada en monumentos y
yacimientos arqueológicos de forma individual, el Ludwig Boltzmann Institute for Archaeological Prospection and Virtual
Archaeology (Austria) va más allá de los límites de yacimientos particulares con el objetivo de entender su contexto
arqueológico. Esto es conseguido mediante la investigación del espacio entre yacimientos y estudiando paisajes
arqueológicos completos yendo desde un hoyo de poste hasta el mapeado de varios kilómetros cuadrados. El enfoque
de prospección multi-metodológico a gran escala y de alta resolución conduce hacia un enorme conjunto de datos digital
que incluye varios Terabytes de información los cuales no habían podido ser manipulados hasta hace poco debido a
limitaciones tecnológicas. Por consiguiente, nuevos programas y métodos de gestión de datos han sido diseñados para
la adquisición y procesado de datos así como interpretación arqueológica para así permitir la extracción de la
información deseada desde estos enormes bancos de datos. El análisis de estos conjuntos de datos generados es
llevado a cabo a través de análisis de sistemas de información geográfica tridimensionales e incluso
cuatridimensionales. El resultado de la prospección de paisajes arqueológicos es transferido de forma visual a la
comunididad científica así como al gran público e interesados en la materia. En muchos casos una visualización de los
resultados científicos e interpretaciones arqueológicas puede ser una herramienta más poderosa y adecuada para
ilustrar y comunicar contextos arqueológicos complejos a un público mayor. Este artículo presenta de forma breve el
gran potencial ofrecido por la combinación de métodos de prospección arqueológica de gran resolución a gran escala y
unos flujos de trabajo estandarizados para integración, interpretación y visualización de datos. La estrategía propuesta
proporciona un contexto para restos arqueológicos enmarcados en paisajes arqueológicos que viene a cambiar nuestra forma de entender monumentos ya conocidos. Pretendemos también superar los desafios que quedan con la ayuda de
ejemplos sacados de excepcionales paisajes arqueológicos que son nuestros estudios de caso a prospectar.Torrejón Valdelomar, J.; Wallner, M.; Trinks, I.; Kucera, M.; Luznik, N.; Löcker, K.; Neubauer, W. (2016). BIG DATA IN LANDSCAPE ARCHAEOLOGICAL PROSPECTION. En 8th International congress on archaeology, computer graphics, cultural heritage and innovation. Editorial Universitat Politècnica de València. 238-246. https://doi.org/10.4995/arqueologica8.2015.4200OCS23824
Fludarabine as a cost-effective adjuvant to enhance engraftment of human normal and malignant hematopoiesis in immunodeficient mice
There is still an unmet need for xenotransplantation models that efficiently recapitulate normal and malignant human hematopoiesis. Indeed, there are a number of strategies to generate humanized mice and specific protocols, including techniques to optimize the cytokine environment of recipient mice and drug alternatives or complementary to the standard conditioning regimens, that can be significantly modulated. Unfortunately, the high costs related to the use of sophisticated mouse models may limit the application of these models to studies that require an extensive experimental design. Here, using an affordable and convenient method, we demonstrate that the administration of fludarabine (FludaraTM) promotes the extensive and rapid engraftment of human normal hematopoiesis in immunodeficient mice. Quantification of human CD45+ cells in bone marrow revealed approximately a 102-fold increase in mice conditioned with irradiation plus fludarabine. Engrafted cells in the bone marrow included hematopoietic stem cells, as well as myeloid and lymphoid cells. Moreover, this model proved to be sufficient for robust reconstitution of malignant myeloid hematopoiesis, permitting primary acute myeloid leukemia cells to engraft as early as 8 weeks after the transplant. Overall, these results present a novel and affordable model for engraftment of human normal and malignant hematopoiesis in immunodeficient mice
Nonmyeloablative, HLA-haploidentical bone marrow transplantation with high dose, post-transplantation cyclophosphamide
Allogeneic stem cell transplantation (SCT) from an HLA-haploidentical relative provides a potentially curative treatment option for hematologic malignancies patients who lack a suitably HLA-matched donor. The greatest challenge to performing HLA-haploidentical SCT has been high rates of graft failure and severe graft-versus-host disease (GVHD). Our group has been exploring high dose, post-transplantation cyclophosphamide (Cy) as prophylaxis of GVHD after nonmyeloablative, HLA-haploidentical bone marrow transplantation, or mini-haploBMT. Among 210 recipients of mini-haploBMT, 87% of patients have experienced sustained donor cell engraftment. The cumulative incidences of grades II-IV acute GVHD and chronic GVHD are 27% and 13%, respectively. Five-year cumulative incidence of non-relapse mortality is 18%, relapse is 55%, and actuarial overall survival and event-free survivals are 35% and 27%, respectively. These outcomes suggest that mini-haploBMT with post-transplantation Cy is associated with acceptably low toxicities and can provide longterm survival, if not cure, for many patients with advanced hematologic malignancies
Rarity of Donor-Derived Malignancy after Allogeneic BMT with High-Dose Post-Transplantation Cyclophosphamide
Lymphocyte Phenotype during Therapy for Acute Graft-versus-Host Disease: A Brief Report from BMT-CTN 0302
AbstractAlthough significant strides have been made in understanding the biology of graft-versus-host disease (GVHD) and its prevention over the last 4 decades, little is known about the different populations of lymphocytes and the changes in response to treatment for this condition. BMT-CTN 0302 was a randomized phase II clinical trial in the Blood and Marrow Transplant Clinical Trials Network that assessed the efficacy of combination therapy with steroids plus pentostatin, mycophenolate mofetil, etanercept, or denileukin diftitox in patients with acute GVHD. Patients enrolled in the study underwent blood analysis by flow cytometry on days 0, 14, and 28 of therapy to enumerate the number of total lymphocytes, T cells, B cells, and lymphocytes expressing activation markers. Baseline total lymphocyte counts and subpopulations were similar in the 4 treatment arms. Responding patients had a smaller decrease in total CD45+ cell count (P = .005) compared with nonresponding patients at day 28. On univariate analysis, those who developed chronic GVHD had significantly higher CD8+ cell counts at day 14 compared with those without it (P = .005). There was no significant association between baseline lymphocyte count and survival. On univariate analysis, among the patients with higher lymphocyte counts at days 14 and 28, there was a trend toward better survival at day 180, although this trend did not reach the predetermined threshold for significance. We found no significant differences in lymphocyte total or subpopulation counts among the 4 treatment arms, and no notable influence on outcomes
feasibility and outcome of haploidentical hematopoietic stem cell transplantation with post transplant high dose cyclophosphamide for children and adolescents with hematologic malignancies an aieop gitmo retrospective multicenter study
Post-transplant high-dose cyclophosphamide (PTCy) is a novel approach to prevent graft-versus-host disease (GVHD) and rejection in patients given haploidentical hematopoietic stem cell transplantation (HSCT). Thirty-three patients with high-risk hematologic malignancies and lacking a match-related or -unrelated donor were treated with PTCy haploidentical HSCT in 5 Italian AIEOP centers. Nineteen patients had a nonmyeloablative preparative regimen (57%), and 14 patients received a full myeloablative conditioning regimen (43%). No patients received serotherapy; GVHD prophylaxis was based on PTCy (50 mg/kg on days +3 and +4) combined with mycophenolate plus tacrolimus or cyclosporine A. Neutrophil and platelet engraftment was achieved on days +17 (range, 14 to 37) and +27 (range, 16 to 71). One patient had autologous reconstitution for anti-HLA antibodies. Acute GVHD grades II to IV and III to IV and chronic GVHD developed in 22% (95% CI, 11 to 42), 3% (95% CI, 0 to 21), and 4% (95% CI, 0 to 27) of cases, respectively. The 1-year overall survival rate was 72% (95% CI, 56 to 88), progression-free survival rate was 61% (95% CI, 43 to 80), cumulative incidence of relapse was 24% (95% CI, 13 to 44), and transplant-related mortality was 9% (95% CI, 3 to 26). The univariate analysis for risk of relapse incidence showed how 3 significant variables, mother as donor (P = .02), donor gender as female (P = .04), and patient gender as female (P = .02), were significantly associated with a lower risk of relapse. Disease progression was the main cause of death. PTCy is a safe procedure also for children and adolescents who have already received several lines of chemotherapy. Among the different diseases, a trend for better 1-year rates of overall survival was obtained for nonacute leukemia patients
PIV Measurements in the Atmospheric Boundary Layer within and above a Mature Corn Canopy. Part I: Statistics and Energy Flux
Particle image velocimetry (PIV) measurements just within and above a mature corn canopy have been performed to clarify the small-scale spatial structure of the turbulence. The smallest resolved scales are about 15 times the Kolmogorov length scale ( 0.4 mm), the Taylor microscales are about , and the Taylor scale Reynolds numbers range between and 3000. The vertical profiles of mean flow and turbulence parameters match those found in previous studies. Frequency spectra, obtained using the data as time series, are combined with instantaneous spatial spectra to resolve more than five orders of magnitude of length scales. They display an inertial range spanning three decades. However, the small-scale turbulence in the dissipation range exhibits anisotropy at all measurement heights, in spite of apparent agreement with conditions for reaching local isotropy, following a high-Reynolds-number wind tunnel study. Directly calculated subgrid-scale (SGS) energy flux, determined by spatially filtering the PIV data, increases significantly with decreasing filter size, providing support for the existence of a spectral shortcut that bypasses the cascading process and injects energy directly into small scales. The highest measured SGS flux is about 40% of the estimated energy cascading rate as determined from a -5/3 fit to the spectra. Terms appearing in the turbulent kinetic energy budget that can be calculated from the PIV data are in agreement with previous results. Evidence of a very strong correlation between dissipation rate and out-of-plane component of the vorticity is demonstrated by a striking similarity between their time series. 1. Introductio
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