529 research outputs found
Computational determination of macroscopic mechanical and thermal material properties for different morphological variants of cast iron
The sensitivity of macroscopic mechanical and thermal properties of grey cast iron is computationally investigated for a variety of graphite morphologies over a wide temperature range. In order to represent common graphite morphologies according to EN ISO 945-1, a synthetic approach is used to algorithmically generate simulation domains. The developed mechanical and thermal model is applied in a large simulation study. The study includes statistical volume elements of the graphite morphology classes GJL-150 and IA2 to IA5, with 10, 11 and 12 v.−% of graphite precipitations, respectively, for a temperature range from 20 to 750 °C. Homogenised macroscopic quantities, such as the Young’s moduli, Poisson’s ratios, yield strengths and thermal conductivities, are predicted for different morphology classes by applying simulation and data analysis tools of the research data infrastructure Kadi4Mat. This is the first work to determine the mechanical and thermal properties of the morphology classes defined in EN ISO 945-
Adoptive Immunotherapy in Chimeras with Donor Lymphocytes
Allogeneic stem cell transplantation has a well-defined indication in the treatment of hematological malignancies. The beneficial immune effect of allogeneic marrow transplantation has long been known, but only recently have methods been developed to separate the graft-versus-leukemia (GVL) effect from graft-versus-host disease (GVHD). Animal experiments have shown that lymphocytes from the marrow donor can be transfused without causing severe GVHD if stable chimerism and tolerance is established. First clinical studies have been preformed in patients with recurrent chronic myelogenous leukemia. In these patients complete molecular remissions were induced that persist without further maintenance treatment. These results have been confirmed in larger multicenter studies in Europe and the USA. The best results were obtained in chronic myelogenous leukemia (CML); repeated successes have been reported in relapsing acute myeloid leukemia (AML), myelodysplastic syndromes and multiple myeloma (MMY), and rare responses were reported for acute lymphoid leukemia. Contrary to animal experiments GVHD has been observed in human patients although to a lesser extent than expected in transplants not given immunosuppression. Secondly myelosuppression has been observed in patients treated with relapsing CML. In CML the incidence of GVHD could be reduced by depleting CD8(+) T cells from the donor lymphocyte concentrate. Alternatively only small numbers of T lymphocytes can be transfused and in the case of failing responses, the numbers of donor lymphocytes may be increased. Results in recurrent AML have been improved by the use of low-dose cytosine arabinoside, granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor mobilized blood cells as compared to lymphocytes only. In MMY the response rate is higher than in AML, but the remissions are of limited duration in most patients. Several protocols have been designed to include preemptive donor lymphocyte transfusion in patients with a high relapse risk after transplantation. Problems remain to avoid chronic GVHD and to circumvent the immune escape mechanisms of leukemia. Copyright (C) 2003 S. Karger AG, Basel
A new modification of the chiron ACS assay for total prostate-specific antigen achieves equimolar response characteristics and improves the detection of prostate cancer
Nonequimolar-response assays for prostate-specific antigen (PSA) are criticized for overestimating total PSA in some men without prostate cancer (PCA), and underestimating total PSA in some men with PCA. We recently studied three nonequimolar-response PSA assays that had undergone modifications. While two of the studied assays achieved equimolar-response characteristics with improved areas under receiver operating characteristic (ROC) curves (AUC), the modification of the Chiron ACS PSA assay (ACS PSA2, Chiron) failed to achieve this. Recently, the ACS assay underwent another modification (ACS PSA, Bayer), which we investigated. Sera from 305 men (155 without and 150 with PCA, PSA greater than or equal to2 and less than or equal to30 mug/l, TandemE) were measured using both modifications of the ACS assay and equimolar-response reference methods (TandemR free and Tandem E, Hybritech). Molar response relative to the reference method and clinical performance (comparison of AUCs) between the previous and new ACS assay modifications were studied. The new modification of the ACS assay (ACS PSA, Bayer) achieved equimolar-response characteristics but reported lower values (average 10%) than the Tandem E assay. Compared to the previous modification (ACS PSA2, Chiron), a 3% improvement in AUC (p=0.01) was found. Using results of the redesigned equimolar-response assay (ACS PSA, Bayer), we calculated that 6 of 155 men without PCA in this sample set could be spared unnecessary biopsy compared with the previous nonequimolar-response assay (ACS PSA2, Chiron) without missing additional PCA (90% sensitivity). These data provide additional evidence for clinical advantages of equimolar-response over nonequimolar-response PSA assay formats
Internet based multicenter study for thoracolumbar injuries: a new concept and preliminary results
This article reports about the internet based, second multicenter study (MCS II) of the spine study group (AG WS) of the German trauma association (DGU). It represents a continuation of the first study conducted between the years 1994 and 1996 (MCS I). For the purpose of one common, centralised data capture methodology, a newly developed internet-based data collection system ( http://www.memdoc.org ) of the Institute for Evaluative Research in Orthopaedic Surgery of the University of Bern was used. The aim of this first publication on the MCS II was to describe in detail the new method of data collection and the structure of the developed data base system, via internet. The goal of the study was the assessment of the current state of treatment for fresh traumatic injuries of the thoracolumbar spine in the German speaking part of Europe. For that reason, we intended to collect large number of cases and representative, valid information about the radiographic, clinical and subjective treatment outcomes. Thanks to the new study design of MCS II, not only the common surgical treatment concepts, but also the new and constantly broadening spectrum of spine surgery, i.e. vertebro-/kyphoplasty, computer assisted surgery and navigation, minimal-invasive, and endoscopic techniques, documented and evaluated. We present a first statistical overview and preliminary analysis of 18 centers from Germany and Austria that participated in MCS II. A real time data capture at source was made possible by the constant availability of the data collection system via internet access. Following the principle of an application service provider, software, questionnaires and validation routines are located on a central server, which is accessed from the periphery (hospitals) by means of standard Internet browsers. By that, costly and time consuming software installation and maintenance of local data repositories are avoided and, more importantly, cumbersome migration of data into one integrated database becomes obsolete. Finally, this set-up also replaces traditional systems wherein paper questionnaires were mailed to the central study office and entered by hand whereby incomplete or incorrect forms always represent a resource consuming problem and source of error. With the new study concept and the expanded inclusion criteria of MCS II 1, 251 case histories with admission and surgical data were collected. This remarkable number of interventions documented during 24 months represents an increase of 183% compared to the previously conducted MCS I. The concept and technical feasibility of the MEMdoc data collection system was proven, as the participants of the MCS II succeeded in collecting data ever published on the largest series of patients with spinal injuries treated within a 2 year period
Validation of a novel instrumentation (FlexOmega system) measuring oar bending moments on-water in rowing
Quantifying rowing performance can facilitate control of training load or assessment of skill level. Accordingly, the FlexOmega system was developed, which records the bending moment of the oar. This work aimed to validate this new instrumentation during a dynamic load case. Two force profiles were first derived from bending moments acquired during on-water rowing (one at race pace, one at training pace). These force profiles were then used to repeatedly load the instrumented oar on a newly developed test bench. To ultimately elaborate how precision and accuracy determined on the test bench affects everyday training, i.e., whether practitioners can reasonably use the FlexOmega system, the measurement variability observed on the test bench was related to the measurement variability seen for on-water measurements.
On the test bench (featuring a mean precision of 99% and mean accuracy of 95%), a mean error of 3 Nm (mean precision: 98%, mean accuracy: 97%) was determined for the FlexOmega system for the force profile A characterised by bending moments of up to 300 Nm (racing simulated, 37 strokes per minute). For the force profile B with lower stroke rate and less force (21 strokes per minute, up to 150 Nm), the mean error was 2 Nm (mean precision: 98%, mean accuracy: 97%).
The measurement variability observed on the test bench was on average for the two force profiles 30% (profile A) and 15% (profile B) of the measurement variability that occurred during on-water rowing. We conclude that improving the measurement characteristics of the instrumentation would hardly result in any practical benefit as on-water measurements seem mainly to be influenced by the rower’s skill level and environmental condition. Thus, the FlexOmega system can be used to control training intensity or to evaluate rowing performance. In addition, the presented approach for elaborating measurement characteristics could contribute to
Proceedings from the National Cancer Institute’s Second International Workshop on the Biology, Prevention, and Treatment of Relapse after Hematopoietic Stem Cell Transplantation: Part III. Prevention and treatment of relapse after allogeneic transplantation
AbstractIn the Second Annual National Cancer Institute’s Workshop on the Biology, Prevention, and Treatment of Relapse after Hematopoietic Stem Cell Transplantation, the Scientific/Educational Session on the Prevention and Treatment of Relapse after Allogeneic Transplantation highlighted progress in developing new therapeutic approaches since the first relapse workshop. Recent insights that might provide a basis for the development of novel, practical clinical trials were emphasized, including utilization of newer agents, optimization of donor lymphocyte infusion (DLI), and investigation of novel cellular therapies. Dr. de Lima discussed pre-emptive and maintenance strategies to prevent relapse after transplantation, for example, recent promising results suggestive of enhanced graft-versus-tumor activity with hypomethylating agents. Dr. Schmid provided an overview of adjunctive strategies to improve cell therapy for relapse, including cytoreduction before DLI, combination of targeted agents with DLI, and considerations in use of second transplantations. Dr. Porter addressed strategies to enhance T cell function, including ex vivo activated T cells and T cell engineering, and immunomodulatory approaches to enhance T cell function in vivo, including exogenous cytokines and modulation of costimulatory pathways
Структура Водораздельной рудной зоны Многовершинного месторождения золота: данные по открытым горным выработкам и керну скважин
Актуальность работы обусловлена необходимостью доизучения структуры Многовершинного месторождения золота с целью повышения точности прогнозирования размеров потенциально рудных жил при проведении разведочных работ. Цель работы: уточнение строения рудной зоны Водораздельная Многовершинного месторождения золота. Методы исследования. Определение кинематики перемещений по разрывным нарушениям было выполнено методами стрейн-анализа. Прослеживание на глубину структур и увязка их пересечений в открытых выработках и керне скважин выполнено по разработанной нами методике учета структурных данных по неориентированному керну. Результаты. Выдвинута гипотеза о генетической связи отдельных систем разрывных нарушений с перемещениями по крупным разломам, определяющим структуру месторождения. Выделены системы сопряженных трещин, соответствующие дорудному, рудному, пострудному этапам становления месторождения. Результаты структурного анализа показывают, что основными рудоконтролирующими структурами являются трещины скола - сместители разрывов северо-восточного простирания, заложенные в предрудный этап и испытавшие подновление в рудный. На основе предложенной методики статистической обработки и учета углов к оси неориентированного керна проведен поиск рудоконтролирующих разрывных структур, прослеженных как на поверхности, так и бурением. Была подтверждена высокая вероятность их идентификации в керне скважин. Глубина экстраполяции выбрана исходя из наиболее вероятной максимальной глубины влияния рудоконтролирующих разрывов и глубины эрозионного среза. Замеренные для контактов жил углы к оси керна были пересчитаны в углы и азимуты падения с шагом поворота вокруг оси керна в 10? - для каждого замера рассчитаны 36 равновероятных положения. Из полученного массива данных по углу и азимуту падения были выбраны с определенным допуском замеры по элементам, сонаправленным структурным элементам, выделенным по поверхности. Таким образом, была оценена глубина развития отдельных систем трещин, относящихся к рудному этапу. Полученные результаты дают количественную характеристику выдержанности рудовмещающих трещин. Сформулированы требования к результатам документации керна для применения использованной методики для увязки пересечений по неориентированному керну.The relevance of the discussed issue is caused by the need of further investigation of the MNV gold deposit tectonic structure. The main aim of the studyis to increase the probability of forecasting the spatial properties of ore-bearing vein zones. The methods used in the study: strain-analysis of vein-containing structures and a new method of recognizing geological structures between the surface and the deep horizons using statistic data obtained from core documentation. The results. The author has put forward the hypothesis on a genetic relation of individual fault systems in the Vodorazdelnaya ore zone and the movements upon major faults. These faults define the structure of the whole Mnogovershinnoye deposit. Few systems of ajoint cracks were dedicated. These fractures were formed before, after and exactly in the ore stage. The carried out analysis shows that shear cracks (the main faults with North-Eastern strike) were the ore-controlling structures. They were formed in pre-ore stage and then they were reactivated in the ore stage. The proposed method for recognizing geological structures is based on finding intersections (data extrapolation) between structural data obtained by open mining and the accounted results of undirected diamond drilling core documentation. The depth of extrapolation was chosen as a maximum dipping depth of single investigated fractures due to erosion. Strike and dip angles for contacts, measured against core axis, were calculated in 36 positions of equal probability as if the plane of the contact was turned around the core axis with 10° discretion. A pair of dipping azimuth and angle was the key to recognize the same structures in trenches and in the core. So the author could measure the vertical dimension of cracks and veinlets as well as their consistency and proposed the requirements for documentation of core for implementation of the discussed method
Strategies for increasing diagnostic yield of community-onset bacteraemia within the emergency department: A retrospective study
Bloodstream infections (BSI) are associated with high mortality. Therefore, reliable methods of detection are of paramount importance. Efficient strategies to improve diagnostic yield of bacteraemia within the emergency department (ED) are needed. We conducted a retrospective analysis of all ED encounters in a high-volume, city-centre university hospital within Germany during a five-year study period from October 2013 to September 2018. A time-series analysis was conducted for all ED encounters in which blood cultures (BCs) were collected. BC detection rates and diagnostic yield of community-onset bacteraemia were compared during the study period (which included 45 months prior to the start of a new diagnostic Antibiotic Stewardship (ABS) bundle and 15 months following its implementation). BCs were obtained from 5,191 out of 66,879 ED admissions (7.8%). Bacteraemia was detected in 1,013 encounters (19.5% of encounters where BCs were obtained). The overall yield of true bacteraemia (defined as yielding clinically relevant pathogens) was 14.4%. The new ABS-related diagnostic protocol resulted in an increased number of hospitalised patients with BCs collected in the ED (18% compared to 12.3%) and a significant increase in patients with two or more BC sets taken (59% compared to 25.4%), which resulted in an improved detection rate of true bacteraemia (2.5% versus 1.8% of hospital admissions) without any decrease in diagnostic yield. This simultaneous increase in BC rates without degradation of yield was a valuable finding that indicated success of this strategy. Thus, implementation of the new diagnostic ABS bundle within the ED, which included the presence of a skilled infectious disease (ID) team focused on obtaining BCs, appeared to be a valuable tool for the accurate and timely detection of community-onset bacteraemia
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