645 research outputs found
Liver failure occurring as a component of exertional heatstroke.
An unusual case of an exertional heatstroke in a healthy 25-year-old man is presented. Initially, the patient was deeply comatose and developed severe rhabdomyolysis and massive hepatic necrosis. Subsequently, he received a liver transplant with remarkable improvement in his mental status, although the rhabdomyolysis continued. The patient died 41 days after the transplant due to a complicating infection. Providing that infections can be effectively controlled, liver transplants might be a promising therapeutic alternative for the few patients who survive the initial neurological consequences of this unusual event
The physiological and physical response to capture stress in sharks
Exhaustive exercise leads to severe metabolic, acid-base, ionic and hematological
changes in sharks. It has been shown that these changes are species-specific and are
affected by the magnitude of the cumulative effects of physiological and physical trauma
associated with capture. Blood lactate, glucose and pH levels are reliable indicators of the
shark stress response and have been extensively studied. Several shark species have
been reported to be able to survive physiological stress unless severe physical trauma
occurs. As comprehensive information about post release mortality is missing, future
investigations should focus on the relationship between physiological disruption and
survival rates of tagged and released sharks
Water flow between soil aggregates
Aggregated soils are structured systems susceptible to non-uniform flow. The hydraulic properties depend on the aggregate fabric and the way the aggregates are assembled. We examined the hydraulic behavior of an aggregate packing. We focused on conditions when water mostly flows through the aggregates, leaving the inter-aggregate pore space air-filled. The aggregates were packed in 3mm thick slabs forming a quasi two-dimensional bedding. The larger aggregates were wetted with water and embedded in smaller aggregates equilibrated at a lower water content. The water exchange between wet and drier aggregates was monitored by neutron radiography. The three-dimensional arrangement of the aggregates was reconstructed by neutron tomography. The water flow turned out to be controlled by the contacts between aggregates, bottle-necks that slow down the flow. The bottle-neck effect is due to the narrow flow cross section of the contacts. The water exchange was simulated by considering the contact area between aggregates as the key parameter. In order to match the observed water flow, the contact area must be reduced by one to two orders of magnitude relative to that obtained from image analysis. The narrowness of the contacts is due to air-filled voids within the contact
The Formation of a Power Multi-Pulse Extreme Ultraviolet Radiation in the Pulse Plasma Diode of Low Pressure
In this paper results are presented on experimental studies of the temporal characteristics of spike extreme ultraviolet (EUV) radiation in the spectral range of 12.2 Ă· 15.8 nm from the anode region of high-current (I = 40 kA) pulsed discharges in tin vapor. It is observed that the intense multi-spike radiation in this range arises at an inductive stage of the discharge. It has been shown that the radiation spikes correlate with the sharp increase of active resistance and of pumped power, due to plasma heating by an electron beam, formed in the double layer of charged particles. It has been observed that for large number of spikes the conversion efficiency of pumped energy into radiationat double layer formation is essentially higher in comparison with collisional heating
Water flow between soil aggregates
Aggregated soils are structured systems susceptible to non-uniform flow. The hydraulic properties depend on the aggregate fabric and the way the aggregates are assembled. We examined the hydraulic behavior of an aggregate packing. We focused on conditions when water mostly flows through the aggregates, leaving the inter-aggregate pore space air-filled. The aggregates were packed in 3mm thick slabs forming a quasi two-dimensional bedding. The larger aggregates were wetted with water and embedded in smaller aggregates equilibrated at a lower water content. The water exchange between wet and drier aggregates was monitored by neutron radiography. The three-dimensional arrangement of the aggregates was reconstructed by neutron tomography. The water flow turned out to be controlled by the contacts between aggregates, bottle-necks that slow down the flow. The bottle-neck effect is due to the narrow flow cross section of the contacts. The water exchange was simulated by considering the contact area between aggregates as the key parameter. In order to match the observed water flow, the contact area must be reduced by one to two orders of magnitude relative to that obtained from image analysis. The narrowness of the contacts is due to air-filled voids within the contact
The Formation of a Power Multi-Pulse Extreme Ultraviolet Radiation in the Pulse Plasma Diode of Low Pressure
In this paper results are presented on experimental studies of the temporal characteristics of spike extreme ultraviolet (EUV) radiation in the spectral range of 12.2 Ă· 15.8 nm from the anode region of high-current (I = 40 kA) pulsed discharges in tin vapor. It is observed that the intense multi-spike radiation in this range arises at an inductive stage of the discharge. It has been shown that the radiation spikes correlate with the sharp increase of active resistance and of pumped power, due to plasma heating by an electron beam, formed in the double layer of charged particles. It has been observed that for large number of spikes the conversion efficiency of pumped energy into radiationat double layer formation is essentially higher in comparison with collisional heating
Novel Cu(I)-5-nitropyridine-2-thiol Cluster with NIR Emission: Structural and Photophysical Characterization
A novel Cu(I) cluster compound has been synthesized by reacting CuI with the 2,2′-dithiobis(5-nitropyridine) ligand under solvothermal conditions. During the reaction, the original ligand breaks into the 5-nitropyridine-2-thiolate moiety, which acts as the coordinating ligand with both N- and S-sites, leading to a distorted octahedral Cu6S6 cluster. The structure has been determined by single-crystal X-ray diffraction and FT-IR analysis, and the photophysical properties have been determined in the solid state by means of steady-state and time-resolved optical techniques. The cluster presents a near-infrared emission showing an unusual temperature dependence: when passing from 77 to 298 K, a blue-shift of the emission band is observed, associated with a decrease in its intensity. Time-dependent-density functional theory calculations suggest that the observed behavior can be ascribed to a complex interplay of excited states, basically in the triplet manifold
Apparent diffusion coefficient for molecular subtyping of non-gadolinium-enhancing WHO grade II/III glioma: volumetric segmentation versus two-dimensional region of interest analysis
OBJECTIVES: To investigate if quantitative apparent diffusion coefficient (ADC) measurements can predict genetic subtypes of non-gadolinium-enhancing gliomas, comparing whole tumour against single slice analysis. METHODS: Volumetric T2-derived masks of 44 gliomas were co-registered to ADC maps with ADC mean (ADCmean) calculated. For the slice analysis, two observers placed regions of interest in the largest tumour cross-section. The ratio (ADCratio) between ADCmeanin the tumour and normal appearing white matter was calculated for both methods. RESULTS: Isocitrate dehydrogenase (IDH) wild-type gliomas showed the lowest ADC values throughout (p < 0.001). ADCmeanin the IDH-mutant 1p19q intact group was significantly higher than in the IDH-mutant 1p19q co-deleted group (p < 0.01). A volumetric ADCmeanthreshold of 1201 × 10-6mm2/s identified IDH wild-type with a sensitivity of 83% and a specificity of 86%; a volumetric ADCratiocut-off value of 1.65 provided a sensitivity of 80% and a specificity of 92% (area under the curve (AUC) 0.9-0.94). A slice ADCratiothreshold for observer 1 (observer 2) of 1.76 (1.83) provided a sensitivity of 80% (86%), specificity of 91% (100%) and AUC of 0.95 (0.96). The intraclass correlation coefficient was excellent (0.98). CONCLUSIONS: ADC measurements can support the distinction of glioma subtypes. Volumetric and two-dimensional measurements yielded similar results in this study. KEY POINTS: • Diffusion-weighted MRI aids the identification of non-gadolinium-enhancing malignant gliomas • ADC measurements may permit non-gadolinium-enhancing glioma molecular subtyping • IDH wild-type gliomas have lower ADC values than IDH-mutant tumours • Single cross-section and volumetric ADC measurements yielded comparable results in this study
Hyaluronic acid combined with mannitol to improve protection against free-radical endothelial damage: Experimental Model
Purpose: To evaluate the protective properties of combined sodium hyaluronate2%
and mannitol 0.5% (Visiol) on the corneal endothelium in the presence of oxidative
stress induced by hydrogen peroxide (H2O2).
Setting: Instituto Oftalmolo´ gico de Alicante, Universidad Miguel Herna´ ndez,
Alicante, Spain.
Methods: This was an exploratory randomized controlled parallel-group, maskedassessor
study of 3 sodium hyaluronate-based ophthalmic viscosurgical devices
(OVDs): Visiol, Healon (sodium hyaluronate 1%), and Viscoat (sodium hyaluronate
3%–chondroitin sodium 4%). The OVDs were tested for protective effects on the
endothelium following oxidative stress induced by H2O2 at increased concentrations:
control (lactated Ringer’s solution), 1mM, 10mM, and 100 mM. Groups without OVD
were used as controls at the same concentrations of peroxide. Each animal received
the same treatment in both eyes (10 eyes per group). Endothelial cell lesion was
assessed using the Janus green photometry absorbance technique.
Results: At 10 mM peroxide concentration, the value of endothelial cell lesion was
significantly lower in the Visiol (16.8%, P Z .0056), Healon (22.2%, P Z .0302), and
Viscoat (21.6%, PZ .0336) groups than in the control group (29.4%, no OVD). There
was a trend in favor of Visiol to more efficiently reduce cell lesions of the endothelium,
than Healon (PZ .055) and Viscoat (P Z .1013). Values of endothelial cell lesion at
peroxide concentrations of 1 mM and 100 mM showed the same trends than those
observed at 10 mM.
Conclusions: All of the OVDs tested efficiently reduced endothelial lesions against
free radicals compared with the control group in which no OVD was used. The
following sequence for the efficacy of endothelial cell protection was established:
Visiol O Viscoat O Healon O no OVD
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Influence of solar-probe inherent atmosphere on in-situ observations
The solar corona is the source of the solar wind, which is responsible for the heliosphere and plays a crucial role in solar/terrestrial phenomena. A comprehensive understanding of these phenomena can be established only by directly measuring ion and electron velocity distributions, plasma waves, and fluxes of energetic particles near the sun. The problem resulting from the inherent atmosphere of a spacecraft moving in the vicinity of the sun and the influence of this atmosphere on in-situ measurements of the solar corona plasma is key to the realization and success of any solar probe mission. To evaluate the influence of the probe-inherent atmosphere on in-situ observations, the authors have developed comprehensive radiation hydrodynamic models. The physics of plasma/probe/vapor interaction are also being developed in a self-consistent model to predict the effect of probe inherent atmosphere on in-situ measurements of corona parameters during solar flares. Interaction of the ionized atmosphere with the ambient natural plasma will create a turbulent shock wave that can affect in-situ measurements and must be taken into account in designing the spacecraft and its scientific components
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