102 research outputs found

    Adaptation and Recovery of a Styrene‐Acrylic Acid Copolymer Surface to Water

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    Drops sliding down an adaptive surface lead to changes of the dynamic contact angles. Two adaptation processes play a role: 1) the adaptation of the surface upon bringing it into contact to the drop (wetting) and 2) the adaptation of the surface after the drop passed (dewetting). In order to study both processes, the authors investigate samples made from random styrene (PS)/acrylic acid (PAA) copolymers, which are exposed to water. Sum-frequency generation spectroscopy and tilted-plate measurements indicate that during wetting, the PS segments displace from the interface, while PAA segments are enriched. This structural adaptation of the PS/PAA random copolymer to water remains after dewetting. Annealing the adapted polymer induces reorientation of the PS segments to the surface

    Роля на 18F-FDG ПЕТ/КТ в диагностичния алгоритъм при злокачествените епителни тумори на глава и шия

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    Туморите на глава и шия са хетерогенна група с разнообразна локализация. Епителните тумори на глава и шия, от които 90% са с плоскоклетъчна хистология, имат сходно развитие, което определя еднотипния диагностичен подход при тях. Целта на настоящия обзор е да направи преглед на литературните данни, касаещи ролята на 18F-FDG ПЕТ/КТ в диагностичния алгоритъм при злокачествени тумори на глава и шия. Проучванията сочат, че целотелесният хибриден образен метод има важна роля при нодално и далечно стадиране, рестадиране, преценка за терапевтичен подход, оценка ефекта от лечение, ранна визуализация на рецидиви, скринингова детекция на синхронни/метахронни тумори и далечни метастази, дори без клинична изява. При пациенти с доказани метастатични шийни лимфни възли с плоскоклетъчна хистология FDG-ПЕТ/КТ помага за водене на насочена биопсия (панендоскопия) и откриване на първично туморно огнище. По-голям брой от пациентите са в напреднал стадий при установяване на заболяването. Точното стадиранe с целотелесно FDG-ПЕТ/КТ изследване, ранна визуализация на далечни метастази и втори първичен тумор при пациенти с епителни злокачествени тумори на глава и шия позволява своевременна промяна на терапевтичния подход, избор на индивидуален терапевтичен план и своевременно лечение според нуждите на пациента

    Case Report of Advanced Childhood Nasopharyngeal Carcinoma: Is Radiotherapy Dose Deescalation the Right Way in Good Responders to Induction Chemotherapy

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    Objectives:. Treatment of childhood NPC similar to adults consists of radiotherapy and chemotherapy, but distant failure is often observed, which led to introducing the induction chemotherapy followed by radiation or chemoradiation. The improved survival rates raised the question of late toxicity. The options for lowering the toxicity rate is the application of advanced radiotherapy techniques like IMRT and VMAT, and deescalation of the radiation dose in good responders and early NPC.Case report: We report a case of13-years old male patient with a high-risk childhood undifferentiated NPC, stage cT4 cN2b M0. He presented with unilateral swallowing at the middle third of left muscle sterenocleidomastoideus, and headache, fever, sore throat and intermittent nasal bleeding for an year. Diagnostic MRI and PET/CT showed good concordance for primary tumor extension and lymph node involvement. Three coursesinduction chemotherapy were applied according to NPC2003-GPOH protocolwith good treatment response. The restaging PET/CT found no distant metastasis. Deescalated protocol of radiotherapy alone was delivered to 50.4 Gy total dose with IGRT, VMAT irradiation technique. At three month PET/CT follow up a solitary bone lesion was detected.Conclusion: The present case proved that in high risk patients more aggressive treatment strategies should be recommended with no omission of concurrent chemotherapy even after full response. Deescalation of radiotherapy dose probably is not appropriate in this group of patients. MRI and PET CT should be used as complementary imaging modalities for early detection of locoregional or distant metastasis

    3D Thermal and CFD Simulations of the Divertor Magnetic Coils for ITER

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    Magnetic diagnostics for the new generation fusion reactor “ITER” are required to be extremely reliable since they provide measurements essential for reactor operation and protection, plasma control and for measurement of several parameters fundamental to the plasma operation, such as plasma current and shape, disruptions and high frequency macro instabilities. ITER magnetic diagnostics consist of various sets of inductive coils and loops mounted on the inner wall, outside the vacuum vessel and in some of the divertor cassettes [1]. All these probes measure magnetic field or flux variations with respect to time, requiring a precise integration of the signals to recover the absolute values of the field components. They operate in a harsh reactor environment, subjected to nuclear heat loads mainly due to the neutron radiation, generated by the burning plasma. Difficult or impossible access after assembly requires reliability, especially in the area of wiring, connections and vacuum feed-throughs and in choosing margin against radiation damage and extreme transient electrical loads. Additional disturbing effects can arise when both a strong transient magnetic field and thermal gradient occur within the coil structure. All these aspects set a serial of strict design requirements and imply a serious technical challenge. This paper is focused on the design, simulation and optimization of the ITER divertor magnetic tangential coils. The divertor is one of the components exposed to the highest heat load in a fusion reactor, with a surface thermal peak load of 20 MW/m2. About 15 % of the energy produced by fusion reactions is absorbed in the divertor region. The radially-oriented divertor cassettes are exposed to inhomogeneous and time-dependent neutron flux. Six similar divertor cassettes are instrumented for magnetic measurements. Six pairs of equilibrium coils (normal and tangential to the mounting surface) are mounted within each of these cassettes. Of those, pairs near the top region of divertor dome will be exposed to the highest nuclear heating of all magnetic sensors, 2.5 MW/m3. The most critical issue for the divertor coils is to minimise Radiation Induced Thermo-Electric Sensitivity (RITES) [2] and Thermally Induced Electromagnetic Force (TIEMF) [3] by combining a proper choice of conductor with low temperature variation in the coil. Instead of Mineral Insulated Cable (MIC), which was foreseen as the preferred winding for the magnetic coils, a winding made of ceramic-coated steel wire was recently proposed [4]. It is thought that, for this wire, maintaining a temperature variation in the wiring below 10K will be sufficient to allow long-pulse operation. Variations of the divertor coil design have been investigated and simulated with the help of ANSYS programme. The aim was to keep the temperature variation in the winding pack within this limit. The optimisation of the coil, based only on a cooling by conduction was not sufficient to meet the 10 K target. Therefore, an actively water cooled coil was designed and simulated by the CFD code – ANSYS CFX

    Prototyping Conventionally Wound High-Frequency Magnetic Sensors for ITER

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    The high-frequency (HF) magnetic sensors for ITER are currently based on a conventional, Mirnov-type, pick-up coil, with an effective area in the range 0.03<(NA)EFF[m2]<0.1; the sensor is required to provide measurements of magnetic instabilities with magnitude around |deltaB/BPOL|~10-4 in the 10kHz to 2MHz frequency range. The physical, mechanical and electrical properties of one representative ITER HF pick-up coil design have been analyzed with particular attention to the manufacturing and assembly process for the winding pack, as its integrity was found to be of concern when performing a coupled electro-magnetic, structural and thermal analysis of the sensor. Three different options for the guiding grooves in that design have been tested, using copper and tungsten for the winding pack, but none of them has been convincing enough due to the likelihood of breakages of the thin grooving and of the tungsten wire itself. Hence, alternative designs still based on a conventional Mirnov-type pick-up coil have been explored, and a non-conventional Mirnov-type pick-up coil was produced using direct laser-cutting of a stainless steel hollow tube, avoiding the difficulties encountered during the winding operations for the conventional Mirnov-type sensors. This process manufacturing appears to be acceptable for HF magnetic sensors of Mirnov-type design in ITER, and it is recommended for future prototyping studies, as the effective area of our first prototype (NA)EFF~0.01m2 was well below the ITER requirement. The electrical characteristics and the frequency response of all these prototypes were evaluated up to 8MHz, with the results in good agreement with model calculations. The conventional Mirnov-type prototypes behave as expected in terms of their main electrical properties, and should satisfy the present measurement performance requirements. Finally, a direct measurement of the effective area of these sensors has shown that the geometrical value is a sufficiently correct estimate of its actual value at low frequencies (<10kHz) when the winding pack closely follows the nominal shape of the coil itself

    Baseline System Design And Prototyping For The Iter High-Frequency Magnetic Diagnostics Set

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    This paper reports the mechanical and electrical tests performed for the prototyping of the ITER high-frequency magnetic sensor and the analysis of the measurement performance of this diagnostic. The current design for the sensor is not suitable for manufacturing for ITER due to the high likelihood of breakages of the un-guided tungsten wire during the winding. A number of alternative designs and manufacturing processes have been investigated, with the Low Temperature Co-fired Ceramic technology giving the best results. The measurement performance of the baseline system design for the high-frequency magnetic diagnostic cannot meet the intended ITER requirements due to its intrinsic spatial periodicities

    Fumarate Reductase Activity Maintains an Energized Membrane in Anaerobic Mycobacterium tuberculosis

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    Oxygen depletion of Mycobacterium tuberculosis engages the DosR regulon that coordinates an overall down-regulation of metabolism while up-regulating specific genes involved in respiration and central metabolism. We have developed a chemostat model of M. tuberculosis where growth rate was a function of dissolved oxygen concentration to analyze metabolic adaptation to hypoxia. A drop in dissolved oxygen concentration from 50 mmHg to 0.42 mmHg led to a 2.3 fold decrease in intracellular ATP levels with an almost 70-fold increase in the ratio of NADH/NAD+. This suggests that re-oxidation of this co-factor becomes limiting in the absence of a terminal electron acceptor. Upon oxygen limitation genes involved in the reverse TCA cycle were upregulated and this upregulation was associated with a significant accumulation of succinate in the extracellular milieu. We confirmed that this succinate was produced by a reversal of the TCA cycle towards the non-oxidative direction with net CO2 incorporation by analysis of the isotopomers of secreted succinate after feeding stable isotope (13C) labeled precursors. This showed that the resulting succinate retained both carbons lost during oxidative operation of the TCA cycle. Metabolomic analyses of all glycolytic and TCA cycle intermediates from 13C-glucose fed cells under aerobic and anaerobic conditions showed a clear reversal of isotope labeling patterns accompanying the switch from normoxic to anoxic conditions. M. tuberculosis encodes three potential succinate-producing enzymes including a canonical fumarate reductase which was highly upregulated under hypoxia. Knockout of frd, however, failed to reduce succinate accumulation and gene expression studies revealed a compensatory upregulation of two homologous enzymes. These major realignments of central metabolism are consistent with a model of oxygen-induced stasis in which an energized membrane is maintained by coupling the reductive branch of the TCA cycle to succinate secretion. This fermentative process may offer unique targets for the treatment of latent tuberculosis

    Microbiological testing of adults hospitalised with community-acquired pneumonia: An international study

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    This study aimed to describe real-life microbiological testing of adults hospitalised with community-acquired pneumonia (CAP) and to assess concordance with the 2007 Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) and 2011 European Respiratory Society (ERS) CAP guidelines. This was a cohort study based on the Global Initiative for Methicillin-resistant Staphylococcus aureus Pneumonia (GLIMP) database, which contains point-prevalence data on adults hospitalised with CAP across 54 countries during 2015. In total, 3702 patients were included. Testing was performed in 3217 patients, and included blood culture (71.1%), sputum culture (61.8%), Legionella urinary antigen test (30.1%), pneumococcal urinary antigen test (30.0%), viral testing (14.9%), acute-phase serology (8.8%), bronchoalveolar lavage culture (8.4%) and pleural fluid culture (3.2%). A pathogen was detected in 1173 (36.5%) patients. Testing attitudes varied significantly according to geography and disease severity. Testing was concordant with IDSA/ATS and ERS guidelines in 16.7% and 23.9% of patients, respectively. IDSA/ATS concordance was higher in Europe than in North America (21.5% versus 9.8%; p&lt;0.01), while ERS concordance was higher in North America than in Europe (33.5% versus 19.5%; p&lt;0.01). Testing practices of adults hospitalised with CAP varied significantly by geography and disease severity. There was a wide discordance between real-life testing practices and IDSA/ATS/ERS guideline recommendations
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