Recent activity of the Be/X-ray binary system SAX J2103.5+4545

Aims. We present a multiwavelength study of the Be/X-ray binary system SAX J2103.5+4545 with the goal of better characterizing the transient behaviour of this source. Methods. SAX J2103.5+4545 was observed by Swift-XRT four times in 2007 from April 25 to May 5, and during quiescence in 2012 August 31. In addition, this source has been monitored from the ground-based astronomical observatories of El Teide (Tenerife, Spain), Roque de los Muchachos (La Palma, Spain) and Sierra Nevada (Granada, Spain) since 2011 August, and from the TUBITAK National Observatory (Antalya, Turkey) since 2009 June. We have performed spectral and photometric temporal analyses in order to investigate the different states exhibited by SAX J2103.5+4545. Results. In X-rays, an absorbed power law model provided the best fit for all the XRT spectra. An iron-line feature at ~6.42 keV was present in all the observations except for that taken during quiescence in 2012. The photon indexes are consistent with previous studies of SAX J2103.5+4545 in high/low luminosity states. Pulsations were found in all the XRT data from 2007 (2.839(2) mHz; MJD 54222.02), but not during quiescence. Both optical outbursts in 2010 and 2012 lasted for about 8/9 months (as the one in 2007 probably did and the current one in 2014 might do) and were most probably caused by mass ejection events from the Be star that eventually fed the circumstellar disc. All of these outbursts started about 3 months before the triggering of the X-ray activity, and about the same period before the maximum of the H_alpha line equivalent width (in emission) was reached at only ~ -5 \AA. In this work we found that the global correlation between the BV variability and the X-ray intensity was also observed at longer wavelengths in the IR domain.Comment: 11 pages, 7 figures, and online material (2 tables). Submitted to A&A in 2014 Januar

Investigation of Single Air Bubble Dynamics and the Effect of Nanoparticles in Rectangular Minichannels

Bubble dynamics and understanding related mechanisms based on force analysis are necessary for better understanding two-phase flow phenomena in small channels. To address this subject, experiments were conducted with injected single air bubbles into rectangular minichannels containing flows of pure water, pure ethanol and TiO2-nanoparticle-based nanofluids, which had a nanoparticle mass fraction of 0.005 wt% for both water and ethanol base fluids. For a range of fluid flow rates, bubble movement and temperature profiles were captured along the channel using high-speed and infrared (IR) cameras, respectively. Upon heating, when using nanofluids, deposition of TiO2 nanoparticles occurred. The results in the channels with cross sectional dimensions of 2 mm × 4 mm and heated length of 7 cm were compared with their counterparts on plain surfaces. Heat fluxes were applied by means of a tantalum film heater on the outer surface of the channel. Bubble dynamics and forces acting on the bubbles were quantitatively analyzed in relation to the fluid type, heat flux, flow rate and deposition. This study highlights the effects of TiO2-nanoparticles (dispersed in two different base fluids) on single-bubble dynamics in minichannels. The nanoparticle deposition was found to have a retarding effect on the bubble movement and led to a more elliptical shape rather than a spherical bubble shape. The bubble behavior is comprehensively assessed in the light of the visualization data and acting forces

Detection of a large Be circumstellar disk during X-ray quiescence of XTE J1946+274

We present a multiwavelength study of the Be/X-ray binary system XTE J1946+274 with the main goal of better characterizing its behavior during X-ray quiescence. We aim to shed light on the mechanism which triggers the X-ray activity for this source. XTE J1946+274 was observed by Chandra-ACIS during quiescence in 2013 March 12. In addition, this source has been monitored from the ground-based astronomical observatories of El Teide (Tenerife, Spain), Roque de los Muchachos (La Palma, Spain) and Sierra Nevada (Granada, Spain) since 2011 September, and from the TUBITAK National Observatory (Antalya, Turkey) since 2005 April. We have performed spectral and photometric temporal analyses in order to investigate the quiescent state and transient behavior of this binary system. In 2006, a long mass ejection event took place from the Be star, lasting for about seven years. We also found that a large Be circumstellar disk was present during quiescence, although major X-ray activity was not observed. We made an attempt to explain this scenario by assuming the permanently presence of a tilted and warped Be circumstellar disk. The 0.3-10 keV X-ray spectrum during quiescence was well fitted with either an absorbed blackbody or absorbed power-law models. The main parameters obtained for these models were kT=1.43+/-0.17 and Gamma=0.9+/-0.4 (with N_H~2-7E+22 cm-2). The 0.3-10 keV flux of the source was ~0.8E-12 erg-1 cm-2 s-1. Pulsations were found with P_pulse=15.757(1) s (MJD 56363.115) and an rms pulse fraction of 32.1(3)%. The observed X-ray luminosity during quiescent periods may be explained by the neutron star being in supersonic propeller regimen.Comment: 9 pages, 7 figures, accepte

In-depth investigation of the molecular pathogenesis of bladder cancer in a unique 26-year old patient with extensive multifocal disease: A case report

Background. The molecular characteristics and the clinical disease course of bladder cancer (BC) in young patients remain largely unresolved. All patients are monitored according to an intensive surveillance protocol and we aim to gain more insight into the molecular pathways of bladder tumors in young patients that could ultimately contribute to patient stratification, improve patient quality of life and reduce associated costs. We also determined whether a biomarker-based surveillance could be feasible. Case Presentation. We report a unique case of a 26-year-old Caucasian male with recurrent non-muscle invasive bladder tumors occurring at a high frequency and analyzed multiple tumors (maximal pTaG2) and urine samples of this patient. Analysis included FGFR3 mutation detection, FGFR3 and TP53 immunohistochemistry, mircosatellite analysis of markers on chromosomes 8, 9, 10, 11 and 17 and a genome wide single nucleotide polymorphism-array (SNP). All analyzed tumors contained a mutation in FGFR3 and were associated with FGFR3 overexpression. None of the tumors showed overexpression of TP53. We found a deletion on chromosome 9 in the primary tumor and this was confirmed by the SNP-array that showed regions of loss on chromosome 9. Detection of all recurrences was possible by urinary FGFR3 mutation analysis. Conclusions. Our findings would suggest that the BC disease course is determined by not only a patient's age, but also by the molecular characteristics of a tumor. This young patient contained typical genetic changes found in tumors of older patients and implies a clinical disease course comparable to older patients. We demonstrate that FGFR3 mutation analysis on voided urine is a simple non-invasive method and could serve as a feasible follow-up approach for this young patient presenting with an FGFR3 mutant tumor

Pituitary and systemic autoimmunity in a case of intrasellar germinoma

Germinomas arising in the sella turcica are difficult to differentiate from autoimmune hypophysitis because of similar clinical and pathological features. This differentiation, nevertheless, is critical for patient care due to different treatments of the two diseases. We report the case of an 11-year-old girl who presented with diabetes insipidus and growth retardation, and was found to have an intra- and supra-sellar mass. Initial examination of the pituitary biopsy showed diffuse lymphocytic infiltration of the adenohypophysis and absent placental alkaline phosphatase expression, leading to a diagnosis of hypophysitis and glucocorticoid treatment. Because of the lack of clinical and radiological response, the pituitary specimen was re-examined, revealing this time the presence of scattered c-kit and Oct4 positive germinoma cells. The revised diagnosis prompted the initiation of radiotherapy, which induced disappearance of the pituitary mass. Immunological studies showed that the patient’s serum recognized antigens expressed by the patient’s own germinoma cells, as well as pituitary antigens like growth hormone and systemic antigens like the Sjögren syndrome antigen B and alpha-enolase. The study first reports the presence of pituitary and systemic antibodies in a patient with intrasellar germinoma, and reminds us that diffuse lymphocytic infiltration of the pituitary gland and pituitary antibodies does not always indicate a diagnosis of autoimmune hypophysitis

First results of the CAST-RADES haloscope search for axions at 34.67 µeV

We present results of the Relic Axion Dark-Matter Exploratory Setup (RADES), a detector which is part of the CERN Axion Solar Telescope (CAST), searching for axion dark matter in the 34.67 µeV mass range. A radio frequency cavity consisting of 5 sub-cavities coupled by inductive irises took physics data inside the CAST dipole magnet for the first time using this filter-like haloscope geometry. An exclusion limit with a 95% credibility level on the axion-photon coupling constant of ga¿ ¿ 4 × 10-13 GeV-1 over a mass range of 34.6738 µeV < ma< 34.6771 µeV is set. This constitutes a significant improvement over the current strongest limit set by CAST at this mass and is at the same time one of the most sensitive direct searches for an axion dark matter candidate above the mass of 25 µeV. The results also demonstrate the feasibility of exploring a wider mass range around the value probed by CAST-RADES in this work using similar coherent resonant cavities. © 2021, The Author(s)

First results on the search for chameleons with the KWISP detector at CAST

We report on a first measurement with a sensitive opto-mechanical force sensor designed for the direct detection of coupling of real chameleons to matter. These dark energy candidates could be produced in the Sun and stream unimpeded to Earth. The KWISP detector installed on the CAST axion search experiment at CERN looks for tiny displacements of a thin membrane caused by the mechanical effect of solar chameleons. The displacements are detected by a Michelson interferometer with a homodyne readout scheme. The sensor benefits from the focusing action of the ABRIXAS X-ray telescope installed at CAST, which increases the chameleon flux on the membrane. A mechanical chopper placed between the telescope output and the detector modulates the incoming chameleon stream. We present the results of the solar chameleon measurements taken at CAST in July 2017, setting an upper bound on the force acting on the membrane of 80pN at 95% confidence level. The detector is sensitive for direct coupling to matter 104 = ßm = 108, where the coupling to photons is locally bound to ß¿ = 1011

Isolation and Characterization of Novel Murine Epiphysis Derived Mesenchymal Stem Cells

BACKGROUND: While bone marrow (BM) is a rich source of mesenchymal stem cells (MSCs), previous studies have shown that MSCs derived from mouse BM (BMMSCs) were difficult to manipulate as compared to MSCs derived from other species. The objective of this study was to find an alternative murine MSCs source that could provide sufficient MSCs. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we described a novel type of MSCs that migrates directly from the mouse epiphysis in culture. Epiphysis-derived MSCs (EMSCs) could be extensively expanded in plastic adherent culture, and they had a greater ability for clonogenic formation and cell proliferation than BMMSCs. Under specific induction conditions, EMSCs demonstrated multipotency through their ability to differentiate into adipocytes, osteocytes and chondrocytes. Immunophenotypic analysis demonstrated that EMSCs were positive for CD29, CD44, CD73, CD105, CD166, Sca-1 and SSEA-4, while negative for CD11b, CD31, CD34 and CD45. Notably, EMSCs did not express major histocompatibility complex class I (MHC I) or MHC II under our culture system. EMSCs also successfully suppressed the proliferation of splenocytes triggered by concanavalin A (Con A) or allogeneic splenocytes, and decreased the expression of IL-1, IL-6 and TNF-α in Con A-stimulated splenocytes suggesting their anti-inflammatory properties. Moreover, EMSCs enhanced fracture repair, ameliorated necrosis in ischemic skin flap, and improved blood perfusion in hindlimb ischemia in the in vivo experiments. CONCLUSIONS/SIGNIFICANCES: These results indicate that EMSCs, a new type of MSCs established by our simple isolation method, are a preferable alternative for mice MSCs due to their better growth and differentiation potentialities