5,017 research outputs found
Swift Observations of the Be/X-ray Transient System 1A 1118-615
We report results of Swift observations for the high mass Be/X-ray binary
system 1A 1118-615, during an outburst stage in January, 2009 and at a flaring
stage in March, 2009. Using the epoch-folding method, we successfully detected
a pulsed period of 407.69(2) sec in the outburst of January and of 407.26(1)
sec after the flare detection in March. We find that the spectral detection for
the source during outburst can be described by a blackbody model with a high
temperature (kT ~ 1-3 keV) and a small radius (R ~ 1 km), indicating that the
emission results from the polar cap of the neutron star. On the other hand, the
spectra obtained after the outburst can further be described by adding an
additional component with a lower temperature (kT ~ 0.1-0.2 keV) and a larger
emission radius (R ~ 10-500 km), which indicates the emission from around the
inner region of an accretion disk. We find that the thermal emission from the
hot spot of the accreting neutron star dominates the radiation in outburst; the
existence of both this X-ray contribution and the additional soft component
suggest that the polar cap and the accretion disk emission might co-exist after
the outburst. Because the two-blackbody signature at the flaring stage is a
unique feature of 1A 1118-615, our spectral results may provide a new insight
to interpret the X-ray emission for the accreting neutron star. The time
separation between the three main outbursts of this system is ~17 years and it
might be related to the orbital period. We derive and discuss the associated
physical properties by assuming the elongated orbit for this specific Be/X-ray
transient.Comment: 9 pages, 3 figures and 4 tables; accepted by MNRA
Stimulatory Effect of 5-Hydroxytryptamine (5-HT) on Rat Capsaicin-Sensitive Lung Vagal Sensory Neurons via Activation of 5-HT\u3csub\u3e3\u3c/sub\u3e Receptors
5-hydroxytryptamine (5-HT) is an inflammatory mediator known to be released in lung. Capsaicin-sensitive lung vagal (CSLV) afferents function as a primary sensor for detecting chemical stimuli and produce consequent reflexes during lung inflammation. To characterize the effect of 5-HT on CSLV afferents, responses of cardiorespiratory reflexes and single-unit C-fiber afferents to right-atrial injections of 5-HT were investigated in anesthetized Sprague-Dawley rats. Bolus injection of 5-HT (8 μg/kg) caused an immediate augmented breath and apnea, accompanied by hypotension and bradycardia. These initial responses were then followed by a brief pressor response and a more sustained depressor response. After a perineural treatment of both cervical vagi with capsaicin to block the conduction of C fibers, 5-HT still triggered the augmented breath, but no longer evoked the apnea, bradycardia and hypotension, indicating an involvement of C-fiber activation. The remaining augmented breath induced by 5-HT after perineural capsaicin treatment was totally eliminated by vagotomy. To further study the effect of 5-HT on CSLV afferents, activities arising from these afferents were determined using the single-fiber recording technique. Right-atrial injection of 5-HT evoked an intense discharge in CSLV afferents in a dose-dependent manner. The highest dose of 5-HT (16 μg/kg) activated 79% (19/24) of CSLV afferents which were also sensitive to capsaicin (0.8 μg/kg). The pretreatment of tropisetron, a selective antagonist of the 5-HT3 receptor, completely blocked CSLV-afferents stimulation induced by 5-HT but did not affect that by capsaicin. Furthermore, a similar afferent response of CSLV afferents was mimicked by phenylbiguanide, a selective agonist of the 5-HT3 receptor. In isolated rat lung vagal C neurons, 5-HT induced intense calcium transients in a dose-dependent manner. The highest concentration (3 μM) of 5-HT activated 67% (18/27) of the CSLV neurons. The 5-HT-induced response was totally abolished by pretreatment of tropisetron. In conclusion, 5-HT exerts an intense stimulatory effect on lung C-fiber terminals mediated through an activation of the 5-HT3 receptor, which may contribute to the airway hypersensitivity under lung inflammation
Mitochondrial redox signaling by p66Shc is involved in regulating androgenic growth stimulation of human prostate cancer cells.
p66Shc is shown to negatively regulate the life span in mice through reactive oxygen species (ROS) production. Recent reports, however, revealed that p66Shc protein level is significantly elevated in several human cancer tissues and growth-stimulated carcinoma cells, suggesting a mitogenic and carcinogenic role for p66Shc. In this communication, we demonstrate for the first time that p66Shc mediates androgenic growth signals in androgen-sensitive human prostate cancer cells through mitochondrial ROS production. Growth stimulation of prostate cancer cells with 5alpha-dihydrotestosterone (DHT) is accompanied by increased p66Shc level and ROS production, which is abolished by antioxidant treatments. However, antioxidant treatments do not affect the transcriptional activity of androgen receptor (AR) as observed by its inability to block DHT-induced prostate-specific antigen expression, an AR-dependent correlate of prostate cancer progression. Elevated expression of p66Shc by cDNA transfection increases the basal cell proliferation and, thus, reduces additional DHT-induced cell proliferation. Furthermore, DHT increases the translocation of p66Shc into mitochondria and its interaction with cytochrome c. Conversely, both redox-negative p66Shc mutant (W134F), which is deficient in cytochrome c interaction, and p66Shc small interfering RNA decrease DHT-induced cell proliferation. These results collectively reveal a novel role for p66Shc-ROS pathway in androgen-induced prostate cancer cell proliferation and, thus, may play a role in early prostate carcinogenesis
A High Efficiency Aluminum-Ion Battery Using an AlCl3-Urea Ionic Liquid Analogue Electrolyte
In recent years, impressive advances in harvesting renewable energy have led
to pressing demand for the complimentary energy storage technology. Here, a
high coulombic efficiency (~ 99.7%) Al battery is developed using
earth-abundant aluminum as the anode, graphite as the cathode, and a cheap
ionic liquid analogue electrolyte made from a mixture of AlCl3 and urea in 1.3
: 1 molar ratio. The battery displays discharge voltage plateaus around 1.9 V
and 1.5 V (average discharge = 1.73 V) and yielded a specific cathode capacity
of ~73 mAh g-1 at a current density of 100 mA g-1 (~ 1.4 C). High coulombic
efficiency over a range of charge-discharge rates and stability over ~150-200
cycles was easily demonstrated. In-situ Raman spectroscopy clearly showed
chloroaluminate anion intercalation/deintercalation of graphite in the cathode
side during charge/discharge and suggested the formation of a stage 2 graphite
intercalation compound when fully charged. Raman spectroscopy and nuclear
magnetic resonance suggested the existence of AlCl4-, Al2Cl7- anions, and
[AlCl2. (urea)n]+ cations in the urea/AlCl3 electrolyte when an excess of AlCl3
was present. Aluminum deposition therefore proceeded through two pathways, one
involving Al2Cl7- anions and the other involving [AlCl2.(urea)n]+ cations. This
battery is a promising prospect for a future high performance, low cost energy
storage device
Development and Validations of a 3-D Numerical Wave Model in Cartesian Grid System Using Level Set Method
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
Integrating the BWM and TOPSIS algorithm to evaluate the optimal token exchanges platform in Taiwan
This research presents procedures for determining the optimal solution of token exchanges platform for investors in Taiwan via integrating the best-worst method (BWM) and the technique for ordering preference by similarity to the ideal solution (TOPSIS). Firstly, this research applies the modified Delphi method to develop the perspectives and factors via literature review and experts opinion. Secondly, the BWM is implemented to obtain weights of perspectives and factors on the linear programming concept. Thirdly, the TOPSIS model is used to rank the optimal solution of the token exchange for investors or corporations. Finally, the proposed model BWMTOPSIS-based procedures will list the optimal token exchanges platform on the three token exchange platforms to investors or corporations in Taiwan on the basis of their rankings in the architecture. The proposed combination framework is able to provide academic and commerce support to investors or corporations in implementing the token into their portfolio as a valuable objective guide to determine the optimal token exchange platform.
First published online 09 December 202
Control Design for Signal Transduction Networks
Signal transduction networks of biological systems are highly complex. How to mathematically describe a signal transduction network by systematic approaches to further develop an appropriate and effective control strategy is attractive to control engineers. In this paper, the synergism and saturation system (S-systems) representations are used to describe signal transduction networks and a control design idea is presented. For constructing mathematical models, a cascaded analysis model is first proposed. Dynamic analysis and controller design are simulated and verified
Construction of Solar Panel Laying System based on Genetic Algorithm
Solar power generation is an important energy resource in most countries. It plays an important role in meeting energy demand, improving energy structure and reducing environmental pollution. The main carrier of solar power generation is solar panels, but the utilization efficiency of most existing solar cells is low, which causes serious waste of solar energy. In response to this phenomenon, we propose a Solar Panel Laying System(SPLS) based on genetic algorithm(GA) to construct solar panels, which solves four problems: the determination of the number of battery components, the layout of the panels, the selection of the inverter and the connection of the inverter. In the SPLS ,we introduce an improved genetic algorithm and multi-objective optimization solution. Under the double premise that the total amount of solar photovoltaic power generation is as large as possible and the cost per unit of power generation is as small as possible, the quantitative solution of the laying system is realized
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