807 research outputs found

    H2-Induced Pressure Broadening and Pressure Shift in the P-Branch of the v3 Band of CH4 from 300 to 700 K

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    For accurate modelling of observations of exoplanet atmospheres, quantification of the pressure broadening of infrared absorption lines for and by a variety of gases at elevated temperatures is needed. High-resolution high-temperature H2-pressure-broadened spectra are recorded for the CH4 v3-band P-branch. Measured linewidths for 116 transitions between 2840 and 3000 cm^{-1} with temperature and pressures ranging between 300 and 700 K, and 10 and 933 Torr, respectively, were used to find rotation- and tetrahedral-symmetry-dependent coefficients for pressure and temperature broadening and pressure-induced lineshifts. The new pressure-broadening data will be useful in radiative-transfer models for retrieving the properties of observed expolanet atmospheres.Comment: 23 pages, 10 figures, 7 tables, Resubmitted for 2nd round of revisions to JQSRT (Journal of Quantitative Spectroscopy & Radiative Transfer). Comments welcome

    Structure and function relationship of human heart from DENSE MRI

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    The study here, suggests a macroscopic structure for the Left Ventricle (LV), based on the heart kinematics which is obtained through imaging. The measurement of the heart muscle deformation using the Displacement ENcoding with Stimulated Echoes (DENSE) MRI, which describes the heart kinematics in the Lagrangian frame work, is used to determine the high resolution patterns of true myocardial strain. Subsequently, the tangential Shortening Index (SI) and the thickening of the LV wall are calculated for each data point. Considering the heart as a positive-displacement pump, the contribution of each segment of LV in the heart function, can be determined by the SI and thickening of the wall in the same portion. Hence the SI isosurfaces show the extent and spatial distribution of the heart activity and reveals its macro structure. The structure and function of the heart are, therefore, related which in turn results in a macroscopic model for the LV. In particular, it was observed that the heart functionality is not uniformly distributed in the LV, and the regions with greater effect on the pumping process, form a band which wraps around the heart. These results, which are supported by the established histological evidence, may be considered as a landmark in connecting the structure and function of the heart through imaging. Furthermore, the compatibility of this model with microscopic observations about the fiber direction is investigated [1]. This method may be used for planning as well as post evaluation of the ventriculoplasty

    Optimisation criterion for pulsatile timing: observation in the human fetus

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    Objectives: Pulsatile cardiac action is an energy consuming process. During pulse wave (PW) travel to the periphery, reflection back to the LV occurs. The concept of wave condition number, WCN, provides evidence that energy consumption of cardiac action is minimised when time of return Tr to LV takes a certain percentage of the cardiac cycle T. Our objective was to assess WCN and reflection timing Tr/T in the human fetus. Methods: Based on the WCN relation: WCN = HR×L/PWV, energy consumption of pulsatile LV action is optimised for WCN = 0.1 (HR: heart rate, L: effective aortic length, PWV: aortic PW velocity; Pahlevan 2014, 2020). Rearranging with Tr = 2L/PWV (figure) yield Tr/T = 0.2 as optimal reflection timing. To obtain Tr in the fetus by Doppler, hemodynamic modelling is required (figure): PWs arrive twice at cerebral circulation: 1st as a primary wave and 2nd after reflection and return. A systolic shoulder (S) in MCA Doppler (MCA‐S) represents this 2nd impulse and delay δt corresponds to Tr (Mills 1970). Results: Tr data of IUGR fetuses with MCA‐S were obtained by this method (Gonser 2018): Tr = 96 ± 15ms (GA 31 ± 3w). T = 423ms (FHR 140bpm) yield Tr/T = 96ms/423ms = 0.23, showing good agreement with optimal reflection timing of 20%, as suggested by the WCN. Conclusions: In spite of circulatory stress, IUGR fetuses maintain nearly optimal pulsatile timing, probably due to the priority of minimal energy consumption. Thus appearance of MCA‐S is not an artifact, but a sign of nearly optimal timed PW reflection

    Une tumeur maligne des gaines des nerfs périphériques compliquant la maladie de Von Recklinghausen

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    Les tumeurs malignes des gaines des nerfs périphériques ou MPNST (Malign Peripheral Nerve Sheath Tumors selon les anglo-saxons) sont des tumeurs rares qui constituent la principale complication des neurofibromatoses de type 1 (NF1) à l'âge adulte. Du fait de leur rareté ces tumeurs posent à la fois des problèmes diagnostiques et thérapeutiques. Nous rapportons une nouvelle observation de MPNST survenue chez une patiente suivie pour une NF1 et dont le traitement a consisté en une exérèse large suivi d'une radiothérapie. Le but de ce travail est d'étudier les critères diagnostiques ainsi que la prise en charge thérapeutique de ce type de tumeurs

    Fahr’s syndrome with seizure presentation

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    Fahr's disease (FD) or Fahr’s syndrome is characterized by basal ganglia calcification with clinical manifestations in the form of neuropsychiatric disorders, neurological symptoms, and cognitive symptoms. FD commonly affects young to middle aged adults. The etiology of this syndrome does not identify a specific agent. Clinical manifestations of this disease incorporate a wide variety of symptoms. The diagnostic criteria of Fahr’s Syndrome consist of bilateral calcification of basal ganglia, progressive neurologic dysfunction, absence of biochemical abnormalities, infectious, traumatic, and a significant family history. Medical imaging techniques for the diagnosis consist of computed tomography (CT), magnetic resonance imaging (MRI), and plain radiography of the skull. This paper presents a case of Fahr’s syndrome in a 60-year-old married prisoner with antisocial personality and seizures. Furthermore, CT and MRI scans showed bilateral symmetric calcifications in the basal ganglia calcification (BGC) and dentate nuclei, cerebellum, and centrum semiovale

    Effects of softwood biochar on the status of nitrogen species and elements of potential toxicity in soils

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    The effects of softwood-derived biochar materials on the chemical behaviour of environmental contaminants in soils were examined in two microcosm scenarios. Addition of the biochar materials into an alkaline sandy soil significantly reduced NH3 volatilization and made it available for conversion into NO3- via nitrification. This process could be enhanced by an increased application rate of biochar produced at a higher pyrolysis temperature. Under the alkaline conditions encountered in the experiment, the biochar surfaces tended to be negatively charged which disfavours the adsorption of NO3-. Therefore, in a fully open system, the addition of biochar materials was likely to contribute to nitrate leaching from the fertilized alkaline sandy soil. The effects of the biochar materials on the immobilization of Fe2+ generated via anaerobic iron reduction in the inundated contaminated soil were not observed, except for the treatment with a higher dose of biochar material produced under pyrolysis temperature at 700°C after the 240th h of incubation. Arsenic showed similar behaviour to Fe. Zn tended to have a higher affinity to the biochar, as compared to Mn. Immobilization of Pb occurred regardless of whether or not the biochar is present

    Structure and function relationship of Zebrafish embryonic heart from confocal microscopy images

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    Confocal microscopy enables us to track myocytes in the embryonic zebrafish heart. The Zeiss LSM 5 Live high speed confocal microscope has been used to take optical sections (at 3 µm intervals and 151 frames per second) through a fluorescently labeled zebrafish heart at two developmental stages (26 and 34 hours post fertilization (hpf)). This data provides unique information allowing us to conjecture on the morphology and biomechanics of the developing vertebrate heart. Nevertheless, the myocytes, whose positions could be determined in a reliable manner, were located sparsely and mostly in one side of the heart tube. This difficulty was overcome using computational methods, that give longitudinal, radial and circumferential displacements of the myocytes as well as their contractile behavior. Applied strain analysis has shown that in the early embryonic heart tube, only the caudal region (near the in-flow) and another point in the middle of the tube can be active; the rest appears to be mostly passive. This statement is based on the delay between major strain and displacement which a material point experiences. Wave-like propagation of all three components of the displacement, especially in the circumferential direction, as well as the almost-periodic changes of the maximum strain support the hypothesis of helical muscle structure embedded in the tube. Changes of geometry in the embryonic heart after several hours are used to verify speculations about the structure based on the earlier images and aforementioned methods

    Fluctuations and transport in a stirred fluid with a mean gradient

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    The effective thermal diffusivity D* and the probability distribution of temperature fluctuations are measured in a stirred fluid across which a temperature gradient is maintained. A distinct mixing transition is observed for D* as a function of Reynolds number R. Above the transitions, the distribution is strongly non-Gaussian and approaches an exponential exp(-‖δT‖/βξ), where β is the local temperature gradient and ξ the correlation length

    The dietary administration of miswak leaf powder promotes performance, antioxidant, immune activity, and resistance against infectious diseases on Nile tilapia (Oreochromis niloticus)

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    The feeding experiment's main purpose was to estimate the influence of fortification of tilapia diets with miswak leaf powder (MLP) on performance, digestive enzyme activity, chemical body composition, antioxidant status, immune response, and resistance against bacterial and fungal infections. O. niloticus fingerlings (15.22 ± 0.06 g) were fed four formulated diets fortified with MLP at 0, 2.5, 5, and 10 g kg−1 diet for 56 days. The fish were injected with Aeromonas hydrophila for 14 days at the end of the feeding trial, and then the mortality percentage was recorded daily in all treated groups. The obtained results showed that dietary administration of MLP at 2.5 g kg−1 recorded significantly higher values in all growth, feed utilization, and feed efficiency parameters. The digestive enzyme activity was significantly (P < 0.01) higher in fish fed a low level of MLP (2.5 or 5 g kg−1) when compared with the control group. Furthermore, the higher concentration of MLP (10 g kg−1) significantly reduced the mortality rate induced by Aeromonas hydrophila infection, increased crude protein percentage in fish body and represented highly in vitro antibacterial and antifungal efficiency. Based on the findings of the challenge tests against A. hydrophilia, higher survival was found in infected fish, explaining that MLP at high level of 10 g kg can be used to resist the outbreak of the A. hydophilia disease in tilapia. In conclusion, our obtained data showed that applied MLP in tilapia diets could promote performance, feed efficiency, antioxidant status, immune activity, and enhanced resistance of O. niloticus against infections
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