34 research outputs found

    A two-fluid model for solar wind fluid with higher order moments

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    A spherically symmetric two-fluid model for the solar wind with higher-order moments is presented. In this model, continuity, momentum, temperature and heat flux equations for two components (electrons and protrons) in steady solar wind states are simultaneously solved by using a time-dependent method. This work is used to compare solutions of the steady-state solar wind with and without higher order moments, and to study the effects of thermal conduction. The coupling between electrons and protrons is also given special attention. The numerical solutions of the steady-state solar wind in both subsonic and supersonic regions between the Sun and 1 AU are obtained and graphically illustrated

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Research on channel and power allocation of cognitive radio network based on hybrid NOMA

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    For the downlink of the cognitive radio network with hybrid non-orthogonal multiple access(NOMA), the improved model for channel and power resource allocation were established with the constraints of the primary user's interference power threshold, the secondary user's minimum information rate, and the number of subchannel multiplexing users. To optimize the problem model, a channel allocation method with adjustable fairness was proposed to obtain the matching result between the channel and the user. The convex approximation and the Charnes-Cooper transformation method were used to obtain the power allocation value of the multiplexing users. The simulation results showed that when the total power of the base station was 25 dBm, the user fairness index of the channel allocation algorithm proposed in this paper was improved by 50%

    Physicochemical property changes of Dendrobium officinale leaf polysaccharide LDOP‐A and it promotes GLP‐1 secretion in NCI‐H716 cells by simulated saliva‐gastrointestinal digestion

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    Abstract A polysaccharide LDOP‐A with a molecular weight of 9.9 kDa was isolated and purified from Dendrobium officinale leaves by membrane separation, cellulose column, and dextran gel column. The Smith degradable products, methylation products, and nuclear magnetic resonance analysis showed that LDOP‐A may be composed of →4)‐Glc‐(1→, →3,6)‐Man‐(1→, and →6)‐Glc‐(1→sugar residues. In vitro, simulated digestion assays showed that LDOP‐A could be partially digested in the stomach and small intestine, and produced a large amount of acetic acid and butyric acid during colonic fermentation. Further cell experiment results illustrated that LDOP‐A‐I (LDOP‐A digested by gastrointestinal tract) could induce glucagon‐like peptide‐1 (GLP‐1) secretion in NCI‐H716 cells without showing any cytotoxicity

    En-Garde! A Review of Fencing Blade Material Development

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    Using two fencing swords manufactured in Europe and China, we investigated the typical materials used for fencing blades and compared the experimental results with the nominal compositions of a variety of steels. We found that spring steels and maraging steels were the primary metals used in fencing blades. The review then provides an overview of the chemical compositions, heat treatment processes, microstructures and associated mechanical properties of these materials. By combining the requirements for the safety of athletes, mechanical behaviors of different steels, and production costs for industry, we introduced possible directions for the heat treatments and processing methods that have the potential to enhance performance and overcome the limitations of previous materials. In addition, an ultra-strong steel, Fe-9.95Mn-0.44C-1.87Al-0.67V which could be a promising new candidate in this area, was recommended. Finally, we suggested that successful cooperation between manufacturers and researchers is necessary to reach the various requirements of fencing blades to meet the growing popularity of fencing in China

    Wave-particle interaction in a plasmaspheric plume observed by a Cluster satellite

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    International audience[1] The wave-particle interaction is a possible candidate for the energy coupling between the ring current and plasmaspheric plumes. In this paper, we present wave and particle observations made by the Cluster C1 satellite in a plasmaspheric plume in the recovery phase of the geomagnetic storm on 18 July 2005. Cluster C1 simultaneously observed Pc1-2 waves and extremely low frequency (ELF) hiss in the plasmaspheric plume. Through an analysis of power spectral density and polarization of the perturbed magnetic field, we identify that the observed Pc1-2 waves are linearly polarized electromagnetic ion cyclotron (EMIC) waves and show that the ELF hiss propagates in the direction of the ambient magnetic field in whistler mode. In the region where the EMIC waves were observed, the pitch angle distribution of ions becomes more isotropic, likely because of the pitch angle scattering by the EMIC waves. It is shown that the ELF hiss and EMIC waves are spatially separated: The ELF hiss is located in the vicinity of the electron density peak within the plume while the EMIC waves are detected in the outer boundary of the plume because of the different propagation characteristics of the ELF hiss and EMIC waves. (2012), Wave-particle interaction in a plasmaspheric plume observed by a Cluster satellite
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