The high-energy emission from the massive colliding-wind binary HD 93129A near periastron

We conducted an observational campaign towards one of the most massive and luminous colliding wind binaries in the Galaxy, HD 93129A, close to its periastron passage in 2018. During this time the source was predicted to be in its maximum of high-energy emission. We present the results from our observations with the X-ray satellites Chandra and NuSTAR and the γ-ray satellite AGILE. High-energy emission coincident with HD 93129A was detected in the X-ray band up to ∼18 keV, whereas in the γ-ray band only upper limits were obtained. We interpret the derived fluxes using a non-thermal radiative model for the wind-collision region. We estimate the fraction of the wind kinetic power that is converted into relativistic electron acceleration and the magnetic field in the wind-collision region. We conclude that multiwavelength, dedicated observing campaigns during carefully selected epochs are a powerful tool for characterizing the relativistic particle content and magnetic field intensity in colliding wind binaries.Fil: del Palacio, Santiago. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: García, Federico. Kapteyn Astronomical Institute; Países Bajos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Altamirano, D.. University of Southampton; Reino UnidoFil: Corcoran, M. Nasa Goddard Space Flight Center; Estados UnidosFil: Hamaguchi, K. Nasa Goddard Space Flight Center; Estados Unidos237th meeting of the American Astronomical SocietyWashingtonEstados UnidosThe American Astronomical Societ

Evidence for non-thermal X-ray emission from the double Wolf-Rayet colliding-wind binary Apep

Context. Massive colliding-wind binaries (CWBs) can be non-thermal sources. The emission produced in their wind-collision region (WCR) encodes information of both the shock properties and the relativistic electrons accelerated in them. The recently discovered system Apep, a unique massive system hosting two Wolf-Rayet stars, is the most powerful synchrotron radio emitter among the known CWBs. It is an exciting candidate in which to investigate the non-thermal processes associated with stellar wind shocks. Aims. We intend to break the degeneracy between the relativistic particle population and the magnetic field strength in the WCR of Apep by probing its hard X-ray spectrum, where inverse-Compton (IC) emission is expected to dominate. Methods. We observed Apep with NuSTAR for 60 ks and combined this with a reanalysis of a deep archival XMM-Newton observation to better constrain the X-ray spectrum. We used a non-thermal emission model to derive physical parameters from the results. Results. We detect hard X-ray emission consistent with a power-law component from Apep. This is compatible with IC emission produced in the WCR for a magnetic field of ≈105–190 mG, corresponding to a magnetic-to-thermal pressure ratio in the shocks of ≈0.007–0.021, and a fraction of ∼1.5 × 10−4 of the total wind kinetic power being transferred to relativistic electrons. Conclusions. The non-thermal emission from a CWB is detected for the first time in radio and at high energies. This allows us to derive the most robust constraints so far for the particle acceleration efficiency and magnetic field intensity in a CWB, reducing the typical uncertainty of a few orders of magnitude to just within a factor of a few. This constitutes an important step forward in our characterisation of the physical properties of CWBs

Secondary hyperparathyroidism in HIV-infected patients: relationship with bone remodeling and response to vitamin D supplementation

Purpose of the study: Secondary hyperparathyroidism (SH) is frequent in HIV-infected patients. However, the causes and consequences are not well established. The aim of our study was to determine the relationship between parathyroid hormone (PTH), vitamin D and bone mineral density (BMD) in HIV-infected patients, and the effect of vitamin D replacement on PTH levels. Methods: Prospective study of 506 patients with at least two sequential serum determinations of PTH and 25-hydroxyvitamin D levels. In all cases, a bone dual X-ray absorptiometry (DEXA) was performed at inclusion. Hyperparathyroidism was defined as a PTH level above 65 pg/ml. Summary of results: Mean age was 44 yrs (24–78), and 75% were male. Mean BMI was 23.7 (17.97–33.11), and only 3% were of black race. Median nadir CD4+ was 200 cells/µL (9–499), and median time of HIV infection was 15.3 yrs (1.7–25.2). At inclusion, 488 patients (86%) were on HAART (31% TDF+PI, 44% TDF+NNRTI, 25% non-TDF based regimen) for a median of 929.5 days (154–1969), and 40% were HCV-coinfected. Median eGFR was 97.9 ml/min (62.14–134.08). Overall, mean serum PTH was 56.3 pg/mL (27.2–95.07). SH was observed in 27% of cases, with a marked influence of seasonality (from 44% in January to 10% in August). Mean levels of vitamin D were 17.45 ng/mL (7.6–40.78), with 16% below 10 ng/ml, 59%<20 ng/ml (deficiency), 85%<30 ng/ml (insufficiency). SH was related to vitamin D deficiency (relative risk, RR, 2.44), age (RR 1.04 per year), and a higher decrease in eGFR (RR 1.03 per ml/min), after adjustment by season, antiretroviral therapy, GFR at baseline, and HCV coinfection. DEXA scan showed 18% osteoporosis and 54% osteopenia, and there was an inverse correlation between PTH levels and T and Z score in femoral neck (r=−0.14, p<0.01), higher in those patients below 40 yrs. Vitamin D supplementation in 181 patients produced a significant decrease in serum PTH (57.2 if not treated vs 50.5 pg/ml, p=0.02, 23% continues with SH) and the only factor associated with lack of response was persistent vitamin D deficiency. Conclusion: SH is relatively frequent in HIV patients, in close relation with vitamin D deficiency. It is associated with bone resorption, especially in the femoral neck. The use of vitamin D supplementation improves SH when levels above 20 ng/ml are achieved

Bloqueo atrioventricular completo en un perro : tratamiento mediante la implantación de un marcapasos endovenosos permanente

Una perra Labrador Retriever presentaba una historia de síncopes, fatiga e intolerancia al ejercicio debida a un bloqueo atrioventricular completo. Debido a que no respondía a la terapia médica (terbutalina, teofilina y posteriormente atropina), fue remitida al Hospital Clínico Veterinario de la Universidad de Murcia con el fin de considerar la implantación de un marcapasos. Las radiografías de tórax mostraron aumento global de la silueta cardiaca y la ecocardiografía puso de manifiesto, además, ligera regurgitación de válvulasatrioventriculares. Se le implantó un marcapasos endovenoso permanente unipolar con modo VVI bajo anestesia general, guiando el cable hacia el ventrículo derecho mediante fluoroscopia con amplificador de imagen. Ocho meses después de la implantación, no se han producido complicaciones y el marcapasos funciona según los parámetros programados.

Lamivudine plus a boosted-protease inhibitor as simplification strategy in HIV-infected patients with toxicity to nucleoside analogues

Purpose of the study: Dual therapy with lamivudine plus a PI boosted with ritonavir (PI/r) could be an alternative to standard triple therapy or PI/r monotherapy as a simplification strategy in patients with toxicity to nucleoside analogues (NA). Methods: Retrospective cohort study of 44 HIV-infected patients on suppressive HAART, with no chronic HBV, who simplified to this dual therapy since 2008. Virological and immunological outcome, lipids and renal changes were evaluated. Summary of results: Mean age was 50 years (38-70), 66% were male, and the median time of HIV infection was 18.6 years. The median nadir CD4+ count was 150 cells/ml (2–407). At inclusion, patients were receiving therapy with lamivudine plus atazanavir/r in 5 cases, lopinavir/r in 12, and darunavir/r in 27, and they had an HIV RNA level<50 copies/ml for a median time of 794 days (129–2344, 90% >6 months). The NA discontinued was tenofovir (27), didanosine (12), AZT (3), and d4T (2). The reasons for changing were toxicity in 76% of cases, especially renal impairment. They had received a mean of 8 regimens before (2–20), and 55% were in CDC-stage C. In 11 cases, history of resistance was available (to NA in 7 cases, including the 210W mutation in four). The mutations 184V was not observed, but four patients (9%) had a previous failure to therapy including 3tC. Mutations in the protease gene were observed in 8 patients (2 to 7 mutations, the most frequent 77I and 93L), without resistance to the current PI/r. During 62.8 patient-years of follow-up (median, 802 days), only 2 patients failed (4.5%), due to incomplete adherence, at 27 and 141 days. Of note, these two patients had no previous failed with 3tC or PI. Overall, CD4+ count increased for 55 cells/ml. No new adverse events were observed, but total cholesterol (from 180 to 246 mg/dl, p=0.007) and triglycerides (from 166 to 195, p=0.01) increased during the first 24 weeks with improvement at 48 weeks. On the other hand, estimated glomerular filtration rate improved during follow up (from 74.2 ml/min to 83.08 ml/min after 48 weeks, p=0.1). Conclusions: Dual therapy with lamivudine plus a boosted PI is safe and effective as simplification strategy in patients with toxicity to NA. This combination could be an alternative to mono or triple therapy in hard to treat patients, although an initial increase in lipid parameters could be observed

Investigation of the WR 11 field at decimeter wavelengths

The massive binary system WR 11 (γ2-Velorum) has recently been proposed as the counterpart of a Fermi source. If this association is correct, this system would be the second colliding wind binary detected in GeV γ-rays. However, the reported flux measurements from 1.4 to 8.64 GHz fail to establish the presence of nonthermal (synchrotron) emission from this source. Moreover, WR 11 is not the only radio source within the Fermi detection box. Other possible counterparts have been identified in archival data, some of which present strong nonthermal radio emission. We conducted arcsec-resolution observations toward WR 11 at very low frequencies (150-1400 MHz) where the nonthermal emission - if existent and not absorbed - is expected to dominate. We present a catalog of more than 400 radio emitters, among which a significant portion are detected at more than one frequency, including limited spectral index information. Twenty-one of these radio emitters are located within the Fermi significant emission. A search for counterparts for this last group pointed at MOST 0808-471; this source is 2´ away from WR 11 and is a promising candidate for high-energy emission, having a resolved structure along 325-1390 MHz. For this source, we reprocessed archive interferometric data up to 22.3 GHz and obtained a nonthermal radio spectral index of - 0.97 ± 0.09. However, multiwavelength observations of this source are required to establish its nature and to assess whether it can produce (part of) the observed γ-rays. WR 11 spectrum follows a spectral index of 0.74 ± 0.03 from 150 to 230 GHz, consistent with thermal emission. We interpret that any putative synchrotron radiation from the colliding-wind region of this relatively short-period system is absorbed in the photospheres of the individual components. Notwithstanding, the new radio data allowed us to derive a mass-loss rate of 2.5 × 10-5 M☉ yr-1, which, according to the latest models for γ-ray emission in WR 11, would suffice to provide the required kinetic power to feed nonthermal radiation processes.Full Table 4 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/A99The radio data presented in this work were obtained with the Giant Metrewave Radio Telescope (GMRT). The GMRT is operated by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research.Fil: Benaglia, Paula. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Observatorio Astronómico de La Plata - Sede Central; ArgentinaFil: del Palacio, Santiago. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Ishwara-Chandra, C. H.. International Centre Of Theoretical Science. Tata Institute Of Fundamental Research; EspañaFil: De Becker, M.. Université de Liège; BélgicaFil: Isequilla, Natacha Laura. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Observatorio Astronómico de La Plata - Sede Central; ArgentinaFil: Saponara, Juliana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentin

An upgrade on the rabbit model of anthracycline-induced cardiomyopathy: shorter protocol, reduced mortality, and higher incidence of overt dilated cardiomyopathy

Current protocols of anthracycline-induced cardiomyopathy in rabbits present with high premature mortality and nephrotoxicity, thus rendering them unsuitable for studies requiring long-term functional evaluation of myocardial function (e.g., stem cell therapy). We compared two previously described protocols to an in-house developed protocol in three groups: Group DOX2 received doxorubicin 2 mg/kg/week (8 weeks); Group DAU3 received daunorubicin 3 mg/kg/week (10 weeks); and Group DAU4 received daunorubicin 4 mg/kg/week (6 weeks). A cohort of rabbits received saline (control). Results of blood tests, cardiac troponin I, echocardiography, and histopathology were analysed. Whilst DOX2 and DAU3 rabbits showed high premature mortality (50% and 33%, resp.), DAU4 rabbits showed 7.6% premature mortality. None of DOX2 rabbits developed overt dilated cardiomyopathy; 66% of DAU3 rabbits developed overt dilated cardiomyopathy and quickly progressed to severe congestive heart failure. Interestingly, 92% of DAU4 rabbits showed overt dilated cardiomyopathy and 67% developed congestive heart failure exhibiting stable disease. DOX2 and DAU3 rabbits showed alterations of renal function, with DAU3 also exhibiting hepatic function compromise. Thus, a shortened protocol of anthracycline-induced cardiomyopathy as in DAU4 group results in high incidence of overt dilated cardiomyopathy, which insidiously progressed to congestive heart failure, associated to reduced systemic compromise and very low premature mortality

Contribution due to clumpy winds to the non-thermal emission in microquasar jets

Powerful jets in high-mass microquasars are likely to be crossed by dense inhomogeneities(clumps) from the stellar winds, which may lead to particle acceleration and thus nonthermalemission in X-rays and gamma-rays. We characterise a typical clump-jet interactionscenario and compute the contribution to the high-energy emission of these systems. Weuse hydrodynamical simulations of a single clump-jet interaction and we use this result tocompute its non-thermal (synchrotron and inverse Compton) radiation. We present severalradiative calculations for a number of clump states, as the clump is disrupted over time,letting different parameters vary (viewing angle, magnetic field). We obtain significantamounts of non-thermal radiation from jet-clump interactions in high-mass microquasars.Fil: de la Cita, M. V.. Universidad de Barcelona. Facultad de Física; EspañaFil: del Palacio, Santiago. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Bosch Ramon, Valentí. Universidad de Barcelona. Facultad de Física; EspañaFil: Paredes Fortuny, X.. Universidad de Barcelona. Facultad de Física; EspañaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Khangulyan, D.. Rikkyo University; JapónXII Scientific Meeting of the Spanish Astronomical SocietyBilbaoEspañaSociedad Española de Astronomí

Evidence for non-thermal X-ray emission from the double WR colliding-wind binary Apep

Context: Massive colliding-wind binaries (CWBs) can be non-thermal sources. The emission produced in their wind-collision region (WCR) encodes information of both the shocks properties and the relativistic electrons accelerated in them. The recently discovered system Apep, a unique massive system hosting two Wolf-Rayet stars, is the most powerful synchrotron radio emitter among the known CWBs, being an exciting candidate to investigate the non-thermal processes associated with stellar wind shocks. Aims: We intend to break the degeneracy between the relativistic particle population and the magnetic field strength in the WCR of Apep by probing its hard X-ray spectrum, where inverse-Compton (IC) emission is expected to dominate. Methods: We observe Apep with NuSTAR for 60 ks and combine this with a re-analysis of a deep archival XMM-Newton observation to better constrain the X-ray spectrum. We use a non-thermal emission model to derive physical parameters from the results. Results: We detect hard X-ray emission consistent with a power-law component. This is compatible with IC emission produced in the WCR for a magnetic field of 100-160 mG and a fraction of ~1.5e-4 of the total wind kinetic power being converted into relativistic electron acceleration. Conclusions: This is the first time that the non-thermal emission from a CWB is detected both in radio and high energies. This allows us to derive the most robust constraints of the particle acceleration efficiency and magnetic field intensity in a CWB so far, reducing the typical uncertainty of a few orders of magnitude to just within a factor of two. This constitutes an important step forward in our characterisation of the physical properties of CWBs.Comment: 12 pages, 6 figures, accepted for publication in A&

Novel compound shows in vivo anthelmintic activity in gerbils and sheep infected by Haemonchus contortus

8 páginas, 2 figuras, 2 tablas.The control of gastrointestinal nematodes in livestock is becoming increasingly difficult due to the limited number of available drugs and the rapid development of anthelmintic resistance. Therefore, it is imperative to develop new anthelmintics that are effective against nematodes. Under this context, we tested the potential toxicity of three compounds in mice and their potential anthelmintic efficacy in Mongolian gerbils infected with Haemonchus contortus. The compounds were selected from previous in vitro experiments: two diamine (AAD-1 and AAD-2) and one benzimidazole (2aBZ) derivatives. 2aBZ was also selected to test its efficacy in sheep. In Mongolian gerbils, the benzimidazole reduced the percentage of pre-adults present in the stomach of gerbils by 95% at a dose of 200 mg/kg. In sheep, there was a 99% reduction in the number of eggs shed in faeces after 7 days at a dose of 120 mg/kg and a 95% reduction in the number of worm adults present in the abomasum. In conclusion, 2aBZ could be considered a promising candidate for the treatment of helminth infections in small ruminants. © 2022, The Author(s).Financial support came from MINECO: RETOS (AGL2016-79813-C2-1R/2R) and MICINN/AEI (PID2020- 119035RB-100). EVG was funded by FPU17/00627, FPU17/05346; VCGA, MAB, MCP and LGP are recipients of Junta de Castilla y León (JCyL) (LE082-18, LE051-18, LE135-19, LE096-20, respectively) and MMV by the Spanish “Ramon y Cajal” Programme (Ministerio de Economía y competitividad; MMV, RYC-2015-18368).Peer reviewe