Periodic signals from the Circinus region: two new cataclysmic variables and the ultraluminous X-ray source candidate GC X-1

The examination of two 2010 Chandra ACIS exposures of the Circinus galaxy resulted in the discovery of two pulsators: CXO J141430.1-651621 and CXOU J141332.9-651756. We also detected 26-ks pulsations in CG X-1, consistently with previous measures. For ~40 other sources, we obtained limits on periodic modulations. In CXO J141430.1-651621, which is ~2 arcmin outside the Circinus galaxy, we detected signals at 6120(1) s and 64.2(5) ks. In the longest observation, the source showed a flux of ~1.1e-13 erg/cm^2/s (absorbed, 0.5-10 keV) and the spectrum could be described by a power-law with photon index ~1.4. From archival observations, we found that the luminosity is variable by ~50 per cent on time-scales of weeks-years. The two periodicities pin down CXO J141430.1-651621 as a cataclysmic variable of the intermediate polar subtype. The period of CXOU J141332.9-651756 is 6378(3) s. It is located inside the Circinus galaxy, but the low absorption indicates a Galactic foreground object. The flux was ~5e-14 erg/cm^2/s in the Chandra observations and showed ~50 per cent variations on weekly/yearly scales; the spectrum is well fit by a power law ~0.9. These characteristics and the large modulation suggest that CXOU J141332.9-651756 is a magnetic cataclysmic variable, probably a polar. For CG X-1, we show that if the source is in the Circinus galaxy, its properties are consistent with a Wolf-Rayet plus black hole binary. We consider the implications of this for ultraluminous X-ray sources and the prospects of Advanced LIGO and Virgo. In particular, from the current sample of WR-BH systems we estimate an upper limit to the detection rate of stellar BH-BH mergers of ~16 events per yr.Comment: 17 pages, 7 figures, 6 tables; accepted for publication in MNRA

Discovery of a 0.42-s pulsar in the ultraluminous X-ray source NGC 7793 P13

NGC 7793 P13 is a variable (luminosity range ~100) ultraluminous X-ray source (ULX) proposed to host a stellar-mass black hole of less than 15 M$_{\odot}$ in a binary system with orbital period of 64 d and a 18-23 M$_{\odot}$ B9Ia companion. Within the EXTraS project we discovered pulsations at a period of ~0.42 s in two XMM-Newton observations of NGC 7793 P13, during which the source was detected at $L_{\mathrm{X}}\sim2.1\times10^{39}$ and $5\times10^{39}$ erg s$^{-1}$ (0.3-10 keV band). These findings unambiguously demonstrate that the compact object in NGC 7793 P13 is a neutron star accreting at super-Eddington rates. While standard accretion models face difficulties accounting for the pulsar X-ray luminosity, the presence of a multipolar magnetic field with $B$ ~ few $\times$ 10$^{13}$ G close to the base of the accretion column appears to be in agreement with the properties of the system.Comment: 5 pages, 5 figures, 2 tables; Version accepted for publication in MNRAS Letter

Swift J201424.9+152930: discovery of a new deeply eclipsing binary with 491 s and 3.4 h modulations

We report on the discovery of a new X-ray pulsator, Swift J201424.9+152930 (Sw J2014). Owing to its X-ray modulation at 491 s, it was discovered in a systematic search for coherent signals in the archival data of the Swift X-ray Telescope. To investigate the nature of Sw J2014, we performed multi-wavelength follow-up observations with space-borne (Swift and XMM-Newton) and ground-based (the 1.5-m Loiano Telescope and the 3.6-m Telescopio Nazionale Galileo) instruments. The X-ray spectrum of Sw J2014 can be described by a hard and highly absorbed power law. The optical observations made it possible to single out the optical counterpart to this source, which displays several variable emission lines and total eclipses lasting ~20 min. Total eclipses of similar length were observed also in X-rays. The study of the eclipses, allowed us to infer a second periodicity of 3.44 h, which we interpret as the orbital period of a close binary system. We also found that the period has not significantly changed over a ~7 yr timespan. Based on the timing signatures of Sw J2014, and its optical and X-ray spectral properties, we suggest that it is a close binary hosting an accreting magnetic white dwarf. The system is therefore a cataclysmic variable of the intermediate polar type and one of the very few showing deep eclipses.Comment: 12 pages, 8 figures, 5 tables; minor changes to match the final MNRAS versio

Enhancing dendritic cell immunotherapy for melanoma using a simple mathematical model

ABSTRACT Background: The immunotherapy using dendritic cells (DCs) against different varieties of cancer is an approach that has been previously explored which induces a specific immune response. This work presents a mathematical model of DCs immunotherapy for melanoma in mice based on work by Experimental Immunotherapy Laboratory of the Medicine Faculty in the Universidad Autonoma de Mexico (UNAM). Method: The model is a five delay differential equation (DDEs) which represents a simplified view of the immunotherapy mechanisms. The mathematical model takes into account the interactions between tumor cells, dendritic cells, naive cytotoxic T lymphocytes cells (inactivated cytotoxic cells), effector cells (cytotoxic T activated cytotoxic cells) and transforming growth factor β cytokine (TGF − β). The model is validated comparing the computer simulation results with biological trial results of the immunotherapy developed by the research group of UNAM. Results: The results of the growth of tumor cells obtained by the control immunotherapy simulation show a similar amount of tumor cell population than the biological data of the control immunotherapy. Moreover, comparing the increase of tumor cells obtained from the immunotherapy simulation and the biological data of the immunotherapy applied by the UNAM researchers obtained errors of approximately 10 %. This allowed us to use the model as a framework to test hypothetical treatments. The numerical simulations suggest that by using more doses of DCs and changing the infusion time, the tumor growth decays compared with the current immunotherapy. In addition, a local sensitivity analysis is performed; the results show that the delay in time “τ ”, the maximal growth rate of tumor “r” and the maximal efficiency of tumor cytotoxic cells rate “aT” are the most sensitive model parameters. Conclusion: By using this mathematical model it is possible to simulate the growth of the tumor cells with or without immunotherapy using the infusion protocol of the UNAM researchers, to obtain a good approximation of the biological trials data. It is worth mentioning that by manipulating the different parameters of the model the effectiveness of the immunotherapy may increase. This last suggests that different protocols could be implemented by the Immunotherapy Laboratory of UNAM in order to improve their results

Looking for blazars in a sample of unidentified high-energy emitting Fermi sources

Context. Based on their overwhelming dominance among associated Fermi γ-ray catalogue sources, it is expected that a large fraction of the unidentified Fermi objects are blazars. Through crossmatching between the positions of unidentified γ-ray sources from the First Fermi Catalog of γ-ray sources emitting above 10 GeV (1FHL) and the ROSAT and Swift/XRT catalogues of X-ray objects and between pointed XRT observations, a sample of 36 potential associations was found in previous works with less than 15 arcsec of positional offset. One-third of them have recently been classified; the remainder, though believed to belong to the blazar class, still lack spectroscopic classifications. Aims. We study the optical spectrum of the putative counterparts of these unidentified gamma-ray sources in order to find their redshifts and to determine their nature and main spectral characteristics. Methods. An observational campaign was carried out on the putative counterparts of 13 1FHL sources using medium-resolution optical spectroscopy from the Osservatorio Astronomico di Bologna in Loiano, Italy; the Telescopio Nazionale Galileo and the Nordic Optical Telescope, both in the Canary Islands, Spain; and the Observatorio Astronómico Nacional San Pedro Mártir in Baja California, Mexico. Results. We were able to classify 14 new objects based on their continuum shapes and spectral features. Conclusions. Twelve new blazars were found, along with one new quasar and one new narrow line Seyfert 1 (NLS1) to be potentially associated with the 1FHL sources of our sample. Redshifts or lower limits were obtained when possible alongside central black hole mass and luminosity estimates for the NLS1 and the quasar.Fil: Marchesini, Ezequiel Joaquín. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Masetti, Nicola. Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna; ItaliaFil: Chavushyan, V.. Instituto Nacional de Astrofísica, Óptica y Electrónica; MéxicoFil: Cellone, Sergio Aldo. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Andruchow, Ileana. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Bassani, L.. Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna; ItaliaFil: Bazzano, A.. Istituto di Astrofisica e Planetologia Spaziali; ItaliaFil: Jiménez-Bailón, E.. Universidad Nacional Autónoma de México; MéxicoFil: Landi, R.. Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna; ItaliaFil: Malizia, A.. Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna; ItaliaFil: Palazzi, E.. Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna; ItaliaFil: Patiño Álvarez, V.. Instituto Nacional de Astrofísica, Óptica y Electrónica; MéxicoFil: Rodríguez Castillo, G. A.. Osservatorio Astronomico di Roma; ItaliaFil: Stephen, J. B.. Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna; ItaliaFil: Ubertini, P.. Istituto di Astrofisica e Planetologia Spaziali; Itali

Malignant pheochromocytoma treated with minimally invasive surgery

Indexación: Web of Science; Scielo.Introducción: El Feocromocitoma es un tumor de células cromafines productor de catecolaminas. Su variedad maligna es muy poco frecuente. Objetivo: Describir 2 casos de Feocromocitoma maligno tratados con cirugía mínimamente invasiva. Casos clínicos: Presentamos 2 pacientes de sexo femenino, de 31 y 51 años respectivamente. La primera con historia de hipertensión arterial de larga data y uso de múltiples fármacos. La segunda paciente debuta con dolor abdominal. En ambos casos los estudios radiológicos y metabólicos confirmaron el diagnóstico de Feocromocitoma. A la primera paciente se le realizó un procedimiento laparoscópico puro, mientras que a la segunda paciente se le realizó un procedimiento laparoscópico asistido por robot. En ambos casos fue necesario realizar adrenalectomía en bloque con el riñón, por compromiso del hilio renal. No hubo complicaciones severas intra ni post-operatorias, como tampoco conversión a cirugía abierta. La histopatología confirmó el diagnóstico de Feocromocitoma maligno con metástasis ganglionares regionales y márgenes quirúrgicos negativos. Ambas se mantienen en control, sin evidencia de recurrencia. Conclusión: El Feocromocitoma maligno puede ser manejado de forma mínimamente invasiva, con morbilidad y resultados oncológicos comparables a cirugía abierta.Introduction: Pheochromocytoma is a tumor derived from chromaffin cells that produces cathecolamines. Malignant pheochromocytomas are extremely rare. Aim: To describe 2 cases of malignant Pheochromocytoma treated with pure laparoscopic and robot assisted surgery. Clinical cases: Two female patients, 31 and 51 years of age, presented with a history of high blood pressure and abdominal pain. Radiologic and metabolic studies confirmed the diagnosis of Pheochromocytoma in both patients. A pure laparoscopic approach was performed in the first patient while a robotic assisted laparoscopy was done in the second patient. In both cases, adrenalectomy with in bloc nephrectomy was performed due to compromise of the renal sinus. There were no complications or conversion to open surgery. Histopathology confirmed the diagnosis of malignant Pheochromocytoma with metastasis to regional nodes and negative surgical margins. At follow-up, there is no evidence of recurrence. Conclusion: Malignant Pheochromocytoma can be treated with minimally invasive surgery, with morbidity and oncological outcomes similar to open approach.http://ref.scielo.org/ksq86

Failure analysis of Co–Cr hip resurfacing prosthesis during solidification

In this study a failure originated during solidification process into the femoral stem component of Hip Resurfacing prosthesis was investigated. Visual inspection, optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and a commercial software simulation ProCAST were carried out in order to determine the cause and solution of this failure. The results exhibited hot tearing, shrinkage porosity and metal oxide films due to inadequate heat dissipation during solidification process, as a consequence of poor investment casting ceramic mold configuration. Also in this paper was improved the casting design solving this kind of defects