Numerical simulation of small perturbation on an accretion disk due to the collision of a star with the disk near the black hole

In this paper, perturbations of an accretion disk by a star orbiting around a black hole are studied. We report on a numerical experiment, which has been carried out by using a parallel-machine code originally developed by D\"{o}nmez (2004). An initially steady state accretion disk near a non-rotating (Schwarzschild) black hole interacts with a "star", modeled as an initially circular region of increased density. Part of the disk is affected by the interaction. In some cases, a gap develops and shock wave propagates through the disk. We follow the evolution for order of one dynamical period and we show how the non-axisymetric density perturbation further evolves and moves downwards where the material of the disk and the star become eventually accreted onto the central body. When the star perturbs the steady state accretion disk, the disk around the black hole is destroyed by the effect of perturbation. The perturbed accretion disk creates a shock wave during the evolution and it loses angular momentum when the gas hits on the shock waves. Colliding gas with the shock wave is the one of the basic mechanism of emitting the $X-$rays in the accretion disk. The series of supernovae occurring in the inner disk could entirely destroy the disk in that region which leaves a more massive black hole behind, at the center of galaxies.Comment: 20pages, 8 figures, accepted for publication in Astrophysics and Space Scienc

Ba3Ga3N5 - A Novel Host Lattice for Eu2+ - Doped Luminescent Materials with Unexpected Nitridogallate Substructure

The alkaline earth nitridogallate Ba3Ga3N5 was synthesized from the elements in a sodium flux at 760°C utilizing weld shut tantalum ampules. The crystal structure was solved and refined on the basis of single-crystal X-ray diffraction data. Ba3Ga3N5 (space group C2/c (No. 15), a = 16.801(3), b = 8.3301(2), c = 11.623(2) Å, β = 109.92 (3)°, Z = 8) contains a hitherto unknown structural motif in nitridogallates, namely, infinite strands made up of GaN4 tetrahedra, each sharing two edges and at least one corner with neighboring GaN4 units. There are three Ba2+ sites with coordination numbers six or eight, respectively, and one Ba2+ position exhibiting a low coordination number 4 corresponding to a distorted tetrahedron. Eu2+ - doped samples show red luminescence when excited by UV irradiation at room temperature. Luminescence investigations revealed a maximum emission intensity at 638 nm (FWHM =2123 cm−1). Ba3Ga3N5 is the first nitridogallate for which parity allowed broadband emission due to Eu2+ - doping has been found. The electronic structure of both Ba3Ga3N5 as well as isoelectronic but not isostructural Sr3Ga3N5 was investigated by DFT methods. The calculations revealed a band gap of 1.53 eV for Sr3Ga3N5 and 1.46 eV for Ba3Ga3N5

A solitary primary subcutaneous hydatid cyst in the abdominal wall of a 70-year-old woman: a case report

<p>Abstract</p> <p>Introduction</p> <p>A solitary primary hydatid cyst in the subcutaneous abdominal wall is an exceptional entity, even in countries where the <it>Echinococcus </it>infestation is endemic.</p> <p>Case presentation</p> <p>We report a case of a 70-year-old Caucasian woman who presented to our hospital with a subcutaneous mass in the para-umbilical area with a non-specific clinical presentation. The diagnosis of subcutaneous hydatid cyst was suspected on the basis of radiological findings. A complete surgical resection of the mass was performed and the patient had an uneventful post-operative recovery. The histopathology confirmed the suspected diagnosis.</p> <p>Conclusion</p> <p>Hydatid cyst should be considered in the differential diagnosis of every subcutaneous cystic mass, especially in regions where the disease is endemic. The best treatment is the total excision of the cyst with an intact wall.</p

Nuclear medicine procedures and the evaluation of male sexual organs: a short review

Sexuality consists of three aspects that are interrelated and inseparable, biological, physiological and social. The biological aspect considers the individual's capability to give and to receive pleasure. In consequence, it covers the functionality of the sexual organs and the physiology of human sexual response cycle. Diagnostic imaging modalities, such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) have been used to evaluate clinical disorders of the male reproductive system. PET and SPECT procedures basically involve the administration of a radiopharmaceutical that has a higher uptake in a specific tumor or tissue. The aim of this brief review is to present some radiopharmaceuticals that have been used in the clinical evaluation of the male sexual organs (testes, prostate, seminal vesicles, penis) related with male sexuality. This information could be useful in better understanding the male sexual response cycle, as well as the sexual disorders, when considering the male sexual organs and the pelvic floor. Moreover, the findings obtained with PET and SPECT imaging could help to evaluate the efficacy of clinical results of therapeutic procedures. In conclusion, the knowledge from these images could aid in better understanding the physiology of the different organs related with sexuality. Furthermore, they could be important tools to evaluate the physiological integrity of the involved organs, to improve clinical strategies and to accompany the patients under treatment

TESS asteroseismology of the known red-giant host stars HD 212771 and HD 203949

International audienc

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016.

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

A Reference High-Pressure CO2\u3c/sub\u3e Adsorption Isotherm for Ammonium ZSM-5 Zeolite: Results of an Interlaboratory Study

© 2018, The Author(s). This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess carbon dioxide adsorption isotherms on NIST Reference Material RM 8852 (ammonium ZSM-5 zeolite), at 293.15 K (20 °C) from 1 kPa up to 4.5 MPa. Eleven laboratories participated in this exercise and, for the first time, high-pressure adsorption reference data are reported using a reference material. An empirical reference equation nex=d(1+exp[(-ln(P)+a)/b])c, [nex-surface excess uptake (mmol/g), P-equilibrium pressure (MPa), a = −6.22, b = 1.97, c = 4.73, and d = 3.87] along with the 95% uncertainty interval (Uk = 2 = 0.075 mmol/g) were determined for the reference isotherm using a Bayesian, Markov Chain Monte Carlo method. Together, this zeolitic reference material and the associated adsorption data provide a means for laboratories to test and validate high-pressure adsorption equipment and measurements. Recommendations are provided for measuring reliable high-pressure adsorption isotherms using this material, including activation procedures, data processing methods to determine surface excess uptake, and the appropriate equation of state to be used

Extrapulmonary small cell sarcinoma: involvement of the brain without evidence of extracranial malignancy by serial PET/CT scans

<p>Abstract</p> <p>Background</p> <p>Extrapulmonary small cell carcinoma (EPSCC) involving the brain is a rare manifestation of an uncommon tumor type.</p> <p>Case presentation</p> <p>We report a 59 year-old Caucasian female diagnosed with an EPSCC involving the left parietal lobe without detectable extracranial primary tumor followed by serial positron emission tomography/computed tomography (PET/CT) imaging. Histopathological examination at both initial presentation and recurrence revealed small cell carcinoma. Serial PET/CT scans of the entire body failed to reveal any extracranial [¹⁸F]2-fluoro-2-deoxy-D-glucose (FDG) avid lesions at either diagnosis or follow-up.</p> <p>Conclusion</p> <p>Chemotherapy may show a transient response in the treatment of EPSCC. Further studies are needed to help identify optimal treatment strategies. Combination PET/CT technology may be a useful tool to monitor EPSCC and assess for an occult primary malignancy.</p

Infection-mediated priming of phagocytes protects against lethal secondary Aspergillus fumigatus challenge

Phagocytes restrict the germination of Aspergillus fumigatus conidia and prevent the establishment of invasive pulmonary aspergillosis in immunecompetent mice. Here we report that immunecompetent mice recovering from a primary A. fumigatus challenge are protected against a secondary lethal challenge. Using RAGγc knock-out mice we show that this protection is independent of T, B and NK cells. In protected mice, lung phagocytes are recruited more rapidly and are more efficient in conidial phagocytosis and killing. Protection was also associated with an enhanced expression of CXCR2 and Dectin-1 on bone marrow phagocytes. We also show that protective lung cytokine and chemokine responses are induced more rapidly and with enhanced dynamics in protected mice. Our findings support the hypothesis that following a first encounter with a non-lethal dose of A. fumigatus conidia, the innate immune system is primed and can mediate protection against a secondary lethal infection