127 research outputs found

    DETECTION OF CLIMATE CHANGE IN THE SLOVAK MOUNTAINS

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    This paper is devoted to detection of some expected changes in the climatological regime (means, variability, frequency distribution) at selected elements due to climate change. Very reliable time series of daily data (air temperature and relative humidity since 1951) measured by the meteorological stations at Hurbanovo, 115 m a.s.l., SW Slovakia, Poprad, 695 m a.sl., at the foot of the High Tatras mountains and LomnickĆ½ Å”tĆ­t, 2635 m a.s.l., the 3rd highest peak in Slovakia have been utilized. More over the daily aerological data measured at the Poprad-GĆ”novce Observatory since 1961 (850 hPa) were elaborated for comparisons with those obtained by ground measurements. Some results are compared also with those designed as climate change scenarios for Slovakia based on the modified CGCM2 GCM outputs. The results showed very significant increase in temperature and decrease in relative humidity in the April to August season after 1990. Only selected results are presented in this extended abstract

    Occurrence of the Portevin Le-Chatelier effect in open-cell microcellular Al-2 wt% Mg

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    Microcellular open-cell metal foams with pores of 75 or 400 pm in diameter and made of pure Al or Al-2 wt% Mg are tested in compression. The aluminum foam exhibits a typical smooth plastic flow and a positive strain rate sensitivity, whereas plastic instabilities and a negative strain rate sensitivity appear in the stress-strain curves of the Al-2 wt Mg foams, indicating the presence of the Portevin Le-Chatelier (PLC) effect. The effect is further confirmed by acoustic emission analysis.Taken together, the data indicate that the PLC effect is caused in this material by the sudden collective deformation of many struts across the material. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

    A systematic review on the use of quantitative imaging to detect cancer therapy adverse effects in normal-appearing brain tissue

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    Cancer therapy for both central nervous system (CNS) and non-CNS tumors has been previously associated with transient and long-term cognitive deterioration, commonly referred to as ā€˜chemo fogā€™. This therapy-related damage to otherwise normal-appearing brain tissue is reported using post-mortem neuropathological analysis. Although the literature on monitoring therapy effects on structural magnetic resonance imaging (MRI) is well established, such macroscopic structural changes appear relatively late and irreversible. Early quantitative MRI biomarkers of therapy-induced damage would potentially permit taking these treatment side effects into account, paving the way towards a more personalized treatment planning. This systematic review (PROSPERO number 224196) provides an overview of quantitative tomographic imaging methods, potentially identifying the adverse side effects of cancer therapy in normal-appearing brain tissue. Seventy studies were obtained from the MEDLINE and Web of Science databases. Studies reporting changes in normal-appearing brain tissue using MRI, PET, or SPECT quantitative biomarkers, related to radio-, chemo-, immuno-, or hormone therapy for any kind of solid, cystic, or liquid tumor were included. The main findings of the reviewed studies were summarized, providing also the risk of bias of each study assessed using a modified QUADAS-2 tool. For each imaging method, this review provides the methodological background, and the benefits and shortcomings of each method from the imaging perspective. Finally, a set of recommendations is proposed to support future research

    Advanced MR techniques for preoperative glioma characterization: Part 1

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    Preoperative clinical magnetic resonance imaging (MRI) protocols for gliomas, brain tumors with dismal outcomes due to their infiltrative properties, still rely on conventional structural MRI, which does not deliver information on tumor genotype and is limited in the delineation of diffuse gliomas. The GliMR COST action wants to raise awareness about the state of the art of advanced MRI techniques in gliomas and their possible clinical translation or lack thereof. This review describes current methods, limits, and applications of advanced MRI for the preoperative assessment of glioma, summarizing the level of clinical validation of different techniques. In this first part, we discuss dynamic susceptibility contrast and dynamic contrast-enhanced MRI, arterial spin labeling, diffusion-weighted MRI, vessel imaging, and magnetic resonance fingerprinting. The second part of this review addresses magnetic resonance spectroscopy, chemical exchange saturation transfer, susceptibility-weighted imaging, MRI-PET, MR elastography, and MR-based radiomics applications. Evidence Level: 3 Technical Efficacy: Stage 2

    Improving the hyperpolarization of (31)p nuclei by synthetic design

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    Traditional (31)P NMR or MRI measurements suffer from low sensitivity relative to (1)H detection and consequently require longer scan times. We show here that hyperpolarization of (31)P nuclei through reversible interactions with parahydrogen can deliver substantial signal enhancements in a range of regioisomeric phosphonate esters containing a heteroaromatic motif which were synthesized in order to identify the optimum molecular scaffold for polarization transfer. A 3588-fold (31)P signal enhancement (2.34% polarization) was returned for a partially deuterated pyridyl substituted phosphonate ester. This hyperpolarization level is sufficient to allow single scan (31)P MR images of a phantom to be recorded at a 9.4 T observation field in seconds that have signal-to-noise ratios of up to 94.4 when the analyte concentration is 10 mM. In contrast, a 12 h 2048 scan measurement under standard conditions yields a signal-to-noise ratio of just 11.4. (31)P-hyperpolarized images are also reported from a 7 T preclinical scanner

    ATP synthase: from single molecule to human bioenergetics

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    ATP synthase (FoF1) consists of an ATP-driven motor (F1) and a H+-driven motor (Fo), which rotate in opposite directions. FoF1 reconstituted into a lipid membrane is capable of ATP synthesis driven by H+ flux. As the basic structures of F1 (Ī±3Ī²3Ī³Ī“Īµ) and Fo (ab2c10) are ubiquitous, stable thermophilic FoF1 (TFoF1) has been used to elucidate molecular mechanisms, while human F1Fo (HF1Fo) has been used to study biomedical significance. Among F1s, only thermophilic F1 (TF1) can be analyzed simultaneously by reconstitution, crystallography, mutagenesis and nanotechnology for torque-driven ATP synthesis using elastic coupling mechanisms. In contrast to the single operon of TFoF1, HFoF1 is encoded by both nuclear DNA with introns and mitochondrial DNA. The regulatory mechanism, tissue specificity and physiopathology of HFoF1 were elucidated by proteomics, RNA interference, cytoplasts and transgenic mice. The ATP synthesized daily by HFoF1 is in the order of tens of kilograms, and is primarily controlled by the brain in response to fluctuations in activity

    Roadmap on holography

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    From its inception holography has proven an extremely productive and attractive area of research. While specific technical applications give rise to 'hot topics', and three-dimensional (3D) visualisation comes in and out of fashion, the core principals involved continue to lead to exciting innovations in a wide range of areas. We humbly submit that it is impossible, in any journal document of this type, to fully reflect current and potential activity; however, our valiant contributors have produced a series of documents that go no small way to neatly capture progress across a wide range of core activities. As editors we have attempted to spread our net wide in order to illustrate the breadth of international activity. In relation to this we believe we have been at least partially successful
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