494 research outputs found

    Rogowski and D-Dot Sensors for Nanosecond High-Voltage and High-Current Pulse Measurements in Impedance-Matched Pulse Generators

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    To measure the output voltage and current in our impedance-matched solid-state Marx generator we developed a voltage and current sensor integrated with the IMG structure. One of the advantages of our IMG structure is the coaxial inner transmission line (TL). The end of this TL is the output connection, which consists of a grounded ring and a smaller high-voltage (HV) inner conductor (coaxial). This structure is ideal for fitting D-dot and Rogowski-coil sensors, as these sensors can benefit from the strictly defined electric and magnetic fields in this waveguide. We developed D-dot and Rogowski-coil sensors on printed circuit boards (PCB) and show their usability in our application for measuring HV pulses. The sensors have a bandwidth of about 200 MHz, measure voltages up to 20 kV, and currents up to hundreds of amperes. Their simple PCB design makes them easily reproducible and cheap compared to commercial sensors. Although designed for our IMG, they can be fit on any coaxial line. Next, we made passive integrators to partly integrate the differentiated sensor signal, which improves the signal quality when measured with an oscilloscope. Finally, after software signal postprocessing, we achieve far better voltage measurements and similar current measurements compared to commercial probes.</p

    Химиотерапия взрослых больных с саркомами мягких тканей

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    В обзоре рассмотрены общие принципы цитостатического лечения взрослых больных с саркомами мягких тканей. Роль химиотерапии при этом заболевании на протяжении последних лет повышается. Hаиболее эффективными цитостатиками являются доксорубицин и ифосфамид, причем у обоих препаратов установлена зависимость эффективности от дозы. Химиотерапию применяют как элемент радикального комбинированного лечения, а также как паллиативный метод при метастатическом процессе. При рабдомиосаркоме химиотерапия эффективна практически при любой стадии заболевания.Chemotherapy has an increasing role in the therapy of soft tissue sarcomas. Meanwhile, chemotherapy of these tumors is frequently considered in general without taking into account the peculiar clinical features of various subtypes. Doxorubicin and ifosfamide are the most active drugs in the treatment of soft tissue sarcomas. Chemotherapy could be used both for radical and for palliative treatment. For rhabdomyosarcoma, chemotherapy is effective in all the stages of such disease

    MRI-based screening for metabolic insufficiency of leg muscle during aerobic exercise in Cystic Fibrosis

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    There is evidence for mitochondrial dysfunction in various tissues in Cystic Fibrosis (CF) including muscle. Among others, a slow rate of high-energy phosphate resynthesis following exercise involving single limb muscle activity was found in human CF using in vivo 31P magnetic resonance spectroscopy (MRS). This raises the question whether this outcome would be ameliorated versus exacerbated if instead an exercise regime is used that puts a significant cardiopulmonary load on the body as in running or bicycling. This is of interest because exercise therapy is commonly prescribed in CF. To investigate this matter, ten pediatric CF patients (age 12–16 years) and healthy peers performed two ramp exercise tests to volitional exhaustion using a bicycle ergometer fit for use inside a MR scanner. Endurance, VO2max and heart rate were determined in the exercise laboratory. Quadriceps muscle energy-and acid/base balance during exercise and recovery were measured on a separate day using MR imaging-based 31P MRS. This study brings together for the first time this powerful biomedical imaging platform and whole body exercise testing in the clinical setting of human CF

    The influence of a six degrees of freedom couch and an individual head support in patient positioning in radiotherapy of head and neck cancer

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    Reproducible patient positioning is important in radiotherapy (RT) of head-and-neck cancer. We therefore compared set-up errors in head-and-neck RT resulting from three different patient positioning systems. Patients were either treated with a standard head support (SHS) and conventional treatment couch (SHS-3, n = 10), a SHS and rotational couch (SHS-6, n = 10), or an individual head support (IHS) and rotational couch (IHS-6, n = 10). Interfraction mean translation vector lenghts were significantly lower for IHS-6 compared to SHS-3 (0.8 ± 0.3 mm vs. 1.4 ± 0.7 mm, P = 0.001). Intrafraction displacement was comparable among cohorts. This study showed that the use of a six degrees of freedom couch combined with an IHS in head-and-neck RT resulted in better interfraction reproducibilit

    Assessing urban ecosystem services in support of spatial planning in the Hague, the Netherlands

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    Green infrastructure (GI) is increasingly addressed in urban planning and research to enhance urban sustainability and resilience through the provisioning of ecosystem services (ES). Yet, few applications exist of planning models for multifunctional GI in high spatial and thematic detail that simultaneously align with stakeholder interests. We address these gaps by developing and presenting a spatially explicit model to inform urban planners on priority areas for multifunctional GI development. This model was made possible by spatial analyses on multiple scales, enabling us to assess ES in sufficient detail, while simultaneously matching the preferences for scale and ES-indicators of decision makers and urban planners. The model involves a novel weighting scheme based upon the local capacity of GI to mitigate problems. We applied our model to the city of The Hague using a set of three policy-relevant problems: air pollution, the urban heat island effect and storm water flooding. Our results show that the capacity of GI to mitigate these problems varies spatially, both within and between ES, and depends on local characteristics of GI and the environmental context. We illustrate the relevance of using a multiscale approach in spatial ES analysis, and underline that GI planning measures should be assessed in high spatial detail due to their often locally distinct ES capacity. Our approach makes important strides towards the deployment of nature-based solutions for urban challenges in the light of demands for increasing resilience and sustainability.Environmental BiologyIndustrial Ecolog

    Institutions versus market forces: Explaining the employment insecurity of European individuals during (the beginning of) the financial crisis

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    In reaction to the recent financial crisis, the European Commission re-stated its view that the balance between flexibility and security is the key to success for the future of the European social economy, as well as its belief in the power of institutional arrangements it deems necessary for this balance. However, do powerful institutions actually counter market forces where flexicurity is concerned? In this paper we address this question by analysing the impact of institutional configurations and market factors on perceived employment insecurity among workers in Europe. We use the 4th wave of the European Social Survey for 2008/2009, which covers 22 countries, and implement a multi-level approach where contextual effects are taken into account and individuals are considered to be embedded within a country. We find that policies that secure one’s income and employability skills, such as passive and active labour market policies, are more important for providing employment security for individuals than institutions that secure one’s current job, such as employment protection. Of the economic and labour market factors, general market conditions (measured as employment rate average) and the strength of the financial crisis (measured as gross domestic product growth rate from 2008 to 2009) are both similarly influential in explaining cross-national variance in the employment insecurity perception of individuals. More generally, and most interestingly, we find that institutional factors lose their significance when market factors are taken into account. Thus, it seems that differences in economic and labour market conditions between countries better explain why workers feel insecure about their employment, than the differences in employment and income policies. Although this result could be influenced by the time period under investigation, which is characterized by a financial crisis, results from previous studies using data from different periods suggest that it is not period-specific

    Harnessing RNA sequencing for global, unbiased evaluation of two new adjuvants for dendritic-cell immunotherapy

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    Effective stimulation of immune cells is crucial for the success of cancer immunotherapies. Current approaches to evaluate the efficiency of stimuli are mainly defined by known flow cytometry-based cell activation or cell maturation markers. This method however does not give a complete overview of the achieved activation state and may leave important side effects unnoticed. Here, we used an unbiased RNA sequencing (RNA-seq)-based approach to compare the capacity of four clinical-grade dendritic cell (DC) activation stimuli used to prepare DC-vaccines composed of various types of DC subsets; the already clinically applied GM-CSF and Frühsommer meningoencephalitis (FSME) prophylactic vaccine and the novel clinical grade adjuvants protamine-RNA complexes (pRNA) and CpG-P. We found that GM-CSF and pRNA had similar effects on their target cells, whereas pRNA and CpG-P induced stronger type I interferon (IFN) expression than FSME. In general, the pathways most affected by all stimuli were related to immune activity and cell migration. GM-CSF stimulation, however, also induced a significant increase of genes related to nonsense-mediated decay, indicating a possible deleterious effect of this stimulus. Taken together, the two novel stimuli appear to be promising alternatives. Our study demonstrates how RNA-seq based investigation of changes in a large number of genes and gene groups can be exploited for fast and unbiased, global evaluation of clinical-grade stimuli, as opposed to the general limited evaluation of a pre-specified set of genes, by which one might miss important biological effects that are detrimental for vaccine efficacy

    The impact of 24 weeks of supervised endurance versus resistance exercise training on left ventricular mechanics in healthy untrained humans.

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    BACKGROUND: In addition to the well-known cardiac structural adaptation to exercise training, little work examined changes in LV mechanics. With new regional and global indices available we sought to determine the effect of 24 weeks endurance versus resistance training on LV mechanics. METHODS AND RESULTS: 23 male subjects were randomly allocated to either a 24-week endurance- or resistance-training program. Pre- and post-training 2D echocardiographic images were acquired. Global LV mechanics (strain [ε]) were recorded in longitudinal, circumferential and radial planes. Rotation was assessed at apical and basal levels. In addition, longitudinal ε-volume loops, across the cardiac cycle, were constructed from simultaneous LV ε (longitudinal and transverse strain) and volume measurements across the cardiac cycle as a novel measure of LV mechanics. Marginal differences in ε and rotation data were found between groups. Post-training, we found no change in global peak ε data. Peak basal rotation significantly increased after training with changes in the endurance group (-2.2±1.9o to -4.5±3.3o) and the resistance group (-2.9±3.0o to -3.4±2.9o) . LV ε-volume loops revealed a modest rightward shift in both groups. CONCLUSIONS: Whilst most global and regional indices of LV mechanics were not significantly altered, 24 weeks of intense supervised exercise training increased basal rotation. Further studies that assess LV mechanics in larger cohorts of subjects and those with cardiovascular disease and risk factors may reveal important training impacts
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