1,184 research outputs found
Geodesics of electrically and magnetically charged test particles in the Reissner-Nordstr\"om space-time: analytical solutions
We present the full set of analytical solutions of the geodesic equations of
charged test particles in the Reissner-Nordstr\"om space-time in terms of the
Weierstra{\ss} , and elliptic functions. Based on the
study of the polynomials in the and equations we characterize
the motion of test particles and discuss their properties. The motion of
charged test particles in the Reissner-Nordstr\"om space-time is compared with
the motion of neutral test particles in the field of a gravitomagnetic
monopole. Electrically or magnetically charged particles in the
Reissner-Nordstr\"om space-time with magnetic or electric charges,
respectively, move on cones similar to neutral test particles in the Taub-NUT
space-times
Geodesic motion in the space-time of a cosmic string
We study the geodesic equation in the space-time of an Abelian-Higgs string
and discuss the motion of massless and massive test particles. The geodesics
can be classified according to the particles energy, angular momentum and
linear momentum along the string axis. We observe that bound orbits of massive
particles are only possible if the Higgs boson mass is smaller than the gauge
boson mass, while massless particles always move on escape orbits. Moreover,
neither massive nor massless particles can ever reach the string axis for
non-vanishing angular momentum. We also discuss the dependence of light
deflection by a cosmic string as well as the perihelion shift of bound orbits
of massive particles on the ratio between Higgs and gauge boson mass and the
ratio between symmetry breaking scale and Planck mass, respectively.Comment: 20 pages including 14 figures; v2: references added, discussion on
null geodesics extended, numerical results adde
X-ray and UV spectroscopy of Galactic diffuse hot gas along the LMC X--3 sight line
We present Suzaku spectra of X-ray emission in the fields just off the LMC
X-3 sight line. OVII, OVIII, and NeIX emission lines are clearly detected,
suggesting the presence of an optically thin thermal plasma with an average
temperature of 2.4E6. This temperature is significantly higher than that
inferred from existing X-ray absorption line data obtained with Chandra grating
observations of LMC X-3, strongly suggesting that the gas is not isothermal. We
then jointly analyze these data to characterize the spatial and temperature
distributions of the gas. Assuming a vertical exponential Galactic disk model,
we estimate the gas temperature and density at the Galactic plane and their
scale heights as 3.6(2.9, 4.7)E6 K and 1.4(0.3, 3.4)E-3 cm^{-3} and 1.4(0.2,
5.2) kpc and kpc, respectively. This characterization can
account for all the \ovi line absorption, as observed in a FUSE spectrum of LMC
X-3, but only predicts less than one tenth of the OVI line emission intensity
typically detected at high Galactic latitudes. The bulk of the OVI emission
most likely arises at interfaces between cool and hot gases.Comment: 10 pages, 7 figures, 3 tables, accepted for publication in ApJ, 200
Upregulation of ERK1/2-eNOS via AT2 Receptors Decreases the Contractile Response to Angiotensin II in Resistance Mesenteric Arteries from Obese Rats
It has been clearly established that mitogen-activated protein kinases (MAPKS) are important mediators of angiotensin II (Ang II) signaling via AT1 receptors in the vasculature. However, evidence for a role of these kinases in changes of Ang II-induced vasoconstriction in obesity is still lacking. Here we sought to determine whether vascular MAPKs are differentially activated by Ang II in obese animals. the role of AT2 receptors was also evaluated. Male monosodium glutamate-induced obese (obese) and non-obese Wistar rats (control) were used. the circulating concentrations of Ang I and Ang II, determined by HPLC, were increased in obese rats. Ang II-induced isometric contraction was decreased in endothelium-intact resistance mesenteric arteries from obese compared with control rats and exhibited a retarded AT1 receptor antagonist response. Blocking of AT2 receptors and inhibition of either endothelial nitric oxide synthase (eNOS) or extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) restored Ang II-induced contraction in obese rats. Western blot analysis revealed increased protein expression of AT2 receptors in arteries from obese rats. Basal and Ang II-induced ERK1/2 phosphorylation was also increased in obese rats. Blockade of either AT1 or AT2 receptors corrected the increased ERK1/2 phosphorylation in arteries from obese rats to levels observed in control preparations. Phosphorylation of eNOS was increased in obese rats. Incubation with the ERK1/2 inhibitor before Ang II stimulation did not affect eNOS phosphorylation in control rats; however, it corrected the increased phosphorylation of eNOS in obese rats. These results clearly demonstrate that enhanced AT2 receptor and ERK1/2-induced, NO-mediated vasodilation reduces Ang II-induced contraction in an endothelium-dependent manner in obese rats.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ São Paulo, Inst Biomed Sci, Dept Pharmacol, São Paulo, BrazilUniv Fed Goias, Div Cardiovasc Physiol, Dept Biol Sci, Jatai, BrazilUniversidade Federal de São Paulo, Div Nephrol, Dept Med, Escola Paulista Med, São Paulo, BrazilUniversidade Federal de São Paulo, Div Nephrol, Dept Med, Escola Paulista Med, São Paulo, BrazilFAPESP: 2007/58311-0FAPESP: 2008/51622-3FAPESP: 2010/03642-5Web of Scienc
Energy Spectra of the Soft X-ray Diffuse Emission in Fourteen Fields Observed with Suzaku
The soft diffuse X-ray emission of twelve fields observed with Suzaku are
presented together with two additional fields from previous analyses. All have
galactic longitudes 65 deg < l < 295 deg to avoid contributions from the very
bright diffuse source that extends at least 30 deg from the Galactic center.
The surface brightnesses of the Suzaku nine fields for which apparently
uncontaminated ROSAT All Sky Survey (RASS) were available were statistically
consistent with the RASS values, with an upper limit for differences of 17 x
10^{-6} c s^{-1} amin^{-2} in R45}-band. The Ovii and Oviii intensities are
well correlated to each other, and Ovii emission shows an intensity floor at ~2
photons s^{-1} cm^{-2 str^{-1} (LU). The high-latitude Oviii emission shows a
tight correlation with excess of Ovii emission above the floor, with (Oviii
intensity) = 0.5 x [(Ovii intensity) -2 LU], suggesting that temperatures
averaged over different line-of-sight show a narrow distribution around ~0.2
keV. We consider that the offset intensity of Ovii arises from the Heliospheric
solar wind charge exchange and perhaps from the local hot bubble, and that the
excess Ovii (2-7 LU) is emission from more distant parts of the Galaxy. The
total bolometric luminosity of this galactic emission is estimated to be 4 x
10^{39} erg s^{-1}, and its characteristic temperature may be related to the
virial temperature of the Galaxy.Comment: 22 Pages, 8 figures, to appear in PASJ (Vol.61 No.4
Energetic Components of Cooperative Protein Folding
A new lattice protein model with a four-helix bundle ground state is analyzed
by a parameter-space Monte Carlo histogram technique to evaluate the effects of
an extensive variety of model potentials on folding thermodynamics. Cooperative
helical formation and contact energies based on a 5-letter alphabet are found
to be insufficient to satisfy calorimetric and other experimental criteria for
two-state folding. Such proteinlike behaviors are predicted, however, by models
with polypeptide-like local conformational restrictions and
environment-dependent hydrogen bonding-like interactions.Comment: 11 pages, 4 postscripts figures, Phys. Rev. Lett. (in press
Psychological process from hospitalization to death among uninformed terminal liver cancer patients in Japan
BACKGROUND: Although the attitude among doctors toward disclosing a cancer diagnosis is becoming more positive, informing patients of their disease has not yet become a common practice in Japan. We examined the psychological process, from hospitalization until death, among uninformed terminal cancer patients in Japan, and developed a psychological model. METHODS: Terminal cancer patients hospitalized during the recruiting period voluntarily participated in in-depth interviews. The data were analyzed by grounded theory. RESULTS: Of the 87 uninformed participants at the time of hospitalization, 67% (N = 59) died without being informed of their diagnosis. All were male, 51–66 years of age, and all experienced five psychological stages: anxiety and puzzlement, suspicion and denial, certainty, preparation, and acceptance. At the end of each stage, obvious and severe feelings were observed, which were called "gates." During the final acceptance stage, patients spent a peaceful time with family, even talking about their dreams with family members. CONCLUSION: Unlike in other studies, the uninformed patients in this study accepted death peacefully, with no exceptional cases. Despite several limitations, this study showed that almost 70% of the uninformed terminal cancer patients at hospitalization died without being informed, suggesting an urgent need for culturally specific and effective terminal care services for cancer patients in Japan
Early administration of IL-6RA does not prevent radiation-induced lung injury in mice
<p>Abstract</p> <p>Background</p> <p>Radiation pneumonia and subsequent radiation lung fibrosis are major dose-limiting complications for patients undergoing thoracic radiotherapy. Interleukin-6 (IL-6) is a pleiotropic cytokine and plays important roles in the regulation of immune response and inflammation. The purpose of this study was to investigate whether anti-IL-6 monoclonal receptor antibody (IL-6RA) could ameliorate radiation-induced lung injury in mice.</p> <p>Methods</p> <p>BALB/cAnNCrj mice having received thoracic irradiation of 21 Gy were injected intraperitoneally with IL-6RA (MR16-1) or control rat IgG twice, immediately and seven days after irradiation. Enzyme-linked immunosorbent assay was used to examine the plasma level of IL-6 and serum amyloid A (SAA). Lung injury was assessed by histological staining with haematoxylin and eosin or Azan, measuring lung weight, and hydroxyproline.</p> <p>Results</p> <p>The mice treated with IL-6RA did not survive significantly longer than the rat IgG control. We observed marked up-regulation of IL-6 in mice treated with IL-6RA 150 days after irradiation, whereas IL-6RA temporarily suppressed early radiation-induced increase in the IL-6 release level. Histopathologic assessment showed no differences in lung section or lung weight between mice treated with IL-6RA and control.</p> <p>Conclusions</p> <p>Our findings suggest that early treatment with IL-6RA after irradiation alone does not protect against radiation-induced lung injury.</p
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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