Exploring the long-term variability and evolutionary stage of the interacting binary DQ Velorum

To progress in the comprehension of the double periodic variable (DPV) phenomenon, we analyse a series of optical spectra of the DPV system DQ Velorum during much of its long-term cycle. In addition, we investigate the evolutionary history of DQ Vel using theoretical evolutionary models to obtain the best representation for the current observed stellar and orbital parameters of the binary. We investigate the evolution of DQ Vel through theoretical evolutionary models to estimate the age and the mass transfer rate which are compared with those of its twin V393 Scorpii. Donor subtracted spectra covering around 60% of the long-term cycle, allow us to investigate time-modulated spectral variations of the gainer star plus the disc. We compare the observed stellar parameters of the system with a grid of theoretical evolutionary tracks computed under a conservative and a non-conservative evolution regime. We have found that the EW of Balmer and helium lines in the donor subtracted spectra are modulated with the long-term cycle. We observe a strenghtening in the EWs in all analysed spectral features at the minimum of the long-term cycle which might be related to an extra line emission during the maximum of the long-term variability. Difference spectra obtained at the secondary eclipse support this scenario. We have found that a non-conservative evolutionary model is a better representation for the current observed properties of the system. The best evolutionary model suggests that DQ Vel has an age of 7.40 x 10^{7} yr and is currently in a low mass transfer rate (-9.8x10^{-9} Msun/yr) stage, after a mass transfer burst episode. Comparing the evolutionary stages of DQ Vel and V393 Sco we observed that the former is an older system with a lower mass transfer rate. This might explain the differences observed in the physical parameters of their accretion discs.Comment: 10 pages, 13 figure

Fundamental stellar and accretion disc parameters of the eclipsing binary DQ Velorum

To add to the growing collection of well-studied double periodic variables (DPVs) we have carried out the first spectroscopic and photometric analysis of the eclipsing binary DQ Velorum to obtain its main physical stellar and orbital parameters. Combining spectroscopic and photometric observations that cover several orbital cycles allows us to estimate the stellar properties of the binary components and the orbital parameters. We also searched for circumstellar material around the more massive star. We separated DQ Velorum composite spectra and measured radial velocities with an iterative method for double spectroscopic binaries. We obtained the radial velocity curves and calculated the spectroscopic mass ratio. We compared our single-lined spectra with a grid of synthetic spectra and estimated the temperature of the stars. We modeled the V-band light curve with a fitting method based on the simplex algorithm, which includes an accretion disc. To constrain the main stellar parameters we fixed the mass ratio and donor temperature to the values obtained by our spectroscopic analysis. We obtain donor and gainer masses, the radii, and temperatures for the stellar components. We find that DQ Vel is a semi-detached system consisting of a B3V gainer and an A1III donor star plus an extended accretion disc around the gainer. The disc is filling 89% of the gainer Roche lobe and it has a concave shape that is thicker at its edge than at its centre. We find a significant sub-orbital frequency of 0.19 d^{-1} in the residuals of the V-band light curve, which we interpret as a pulsation of an slowly pulsating B-type (SPB) of a gainer star. We also estimate the distance to the binary (3.1 kpc) using the absolute radii, apparent magnitudes, and effective temperatures of the components found in our study.Comment: 12 pages, 13 Postscript figure

Optical spectroscopy of DPVs and the case of LP Ara

We present preliminary results of our spectroscopic campaign of a group of intermediate mass interacting binaries dubbed "Double Periodic Variables" (DPVs), characterized by orbital light curves and additional long photometric cycles recurring roughly after 33 orbital periods (Mennickent et al. 2003, 2005). They have been interpreted as interacting, semi-detached binaries showing cycles of mass loss into the interstellar medium (Mennickent et al. 2008, Mennickent & Kolaczkowski 2009). High resolution Balmer and helium line profiles of DPVs can be interpreted in terms of mass flows in these systems. A system solution is given for LP Ara, based on modeling of the ASAS V-band orbital light curve and the radial velocity of the donor star.Comment: To be published in the proceedings book of the IAUS 272, Cambridge University Press. Editors C. Neiner, G. Wade, G. Meynet and G. Peter

Manejo quirúrgico de la poliposis nasosinusal

Indexación: ScieloIntroducción: La poliposis nasosinusal es un proceso inflamatorio crónico de la mucosa rinosinusal, de etiología desconocida, y que requiere de tratamiento quirúrgico en más de 50% de los pacientes. Objetivo: Evaluar los resultados de la cirugía endoscópica en pacientes con poliposis nasosinusal en el Hospital Barros Luco-Trudeau. Material y método: Estudio retrospectivo de 180 fichas clínicas de pacientes operados en este hospital en el período 1999-2008. Resultados: La distribución según sexo fue de 63% varones y 37% mujeres (p <0,001) y el promedio etario, de 44,9 años. El motivo principal de consulta fue la obstrucción nasal. Un tercio de los pacientes tenía poliposis masiva. El 17% se asoció con asma. Más del 50% de los pacientes usó corticoides inhalados en el preoperatorio. En el 58% se realizó cirugía endoscópica hasta etmoides anterior. No hubo complicaciones mayores en esta serle estudiada. La recidiva global fue de 24%. El promedio de meses libres de recidiva fue 46,7 meses (IC 95%: 37,5-55,5), con una recidiva de 25% al año de seguimiento. No se encontró asociación entre recidiva y los factores de riesgo estudiados. Discusión: En comparación con la literatura, se observa similares características demográficas. Sin embargo, los factores de riesgo de recidiva no fueron significativos, aparentemente debido a una baja prevalenciay a pérdida del seguimiento. La tasa de recidiva aumenta con el tiempo, motivo por el cual se requiere un seguimiento a largo plazo. Conclusiones: No se detectó asociación entre recidiva y los factores de riesgo clásicamente descritos en la literatura. Las recidivas fueron tardías y se obtuvieron tasas de recidiva similares a lo publicado en la literatura.Introduction: Sinonasal polyposis is a chronic inflammatory process rhinosinusal mucosa of unknown etiology which in over 50% of patients requires surgical treatment. Aim: To evaluate the results of endoscopic surgery in patients with sinonasal polyposis in the Barros Luco-Trudeau Hospital. Material and method: Retrospective study of 180 medical records of patients operated at this hospital from 1999 to 2008. Results: The sexual distribution was 63% male and 37% women (p <0.001). The average age was 44.9years. The chief complaint was nasal obstruction. A third of the patients had massive polyposis. The 17% was associated with asthma. Over 50% of patients used inhaled corticosteroids preoperatively in 58% performed endoscopic surgery to anterior ethmoid. There were no major complications in these series studied. The overall recurrence was 24%. The average number of months free of recurrence was 46.7 months (95% Cl 37.5 to 55.5) with a recurrence of 25% per year of follow up. We found no association between recurrence and the risk factors studied. Discussion: Comparing with the lierature, we see the same demographic characteristics but risk factors for recurrence are not significant, apparently due to the low prevalence and loss of follow-up. The recurrence rate is increased over time and therefore requires a long-term monitoring. Conclusions: We found no association between recurrence and the risk factors classically described in literature. Recurrences were late and we had similar recurrence rates to publish in the lierature.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-48162010000100002&nrm=is

Filamentous fungi isolated and identified from Antarctic soil (Fildes Bay, Antarctica)

Purpose: Antarctica is a unique place with extreme environmental conditions, including low temperature, high solar radiation, low nutrient availability and strong winds. This different environment represents a gateway to studies on the taxonomy, ecology, and biotechnology of organisms under extreme conditions. Fungi are ubiquitous and diverse organisms in Antarctica and have been described as growing in different substrates such as plants, soil, rocks, ice, snow, and animals. To survive in such extreme conditions fungi might display unusual biochemical pathways able to generate specific or novel compounds with biotechnological relevance. Before accessing the fungal biotechnological potential, knowing the fungal species is mandatory. The main aim of this study was to isolate and identify fungal strains from Antarctic soil (Fildes Bay, Antarctica). Material and methods: Soil samples were collected using a 4x25 m transect at a depth of 0- 20 cm in different geographic areas of Fildes Bay (Antarctica). A total of 13 composed soil samples were collected. Composed soil aqueous suspensions were incubated on Potato Dextrose Agar (PDA), Dichloran Glycerol Agar 18% (DG18) and Dichloran Rose Bengal Chloramphenicol Agar (DRBC) media at 10 ºC for 21 days in the dark. Subsequently, filamentous fungi were isolated and cultured on PDA. The morphological identification of the isolated strains was carried out according to the classic macro- and micromorphological taxonomy. Results: A set of c.a. 1600 fungal strains belonging to the genera Acremonium, Aspergillus, Cladosporium, Mortierella, Mucor, Penicillium, Psudogymnoascus and other four nonidentified fungal genera were isolated. In addition, a relationship between the geographical area of the soil sample and the fungal genera was observed. Conclusions: Despite both the adverse environmental conditions and Antarctic soils that are not completely devoid of life, it was possible to observe a great diversity of filamentous fungi in some assessed soil samples. This indicates the ability of filamentous fungi in adapting to and survive in extreme conditions such as some of those found in Antarctica. This work represents the first report of large-scale fungal isolation in Fildes Bay, Antarctica. Molecular biology identification is being developed for isolated fungal strains.info:eu-repo/semantics/publishedVersio

Evaluation of lipid extraction methods from Antarctic filamentous fungi

Purpose: The benefits of natural compounds have been studied for decades for the development of new technologies to answer the global change challenges. In order to develop these new technologies, lipids represent a great class of bioactive molecules. However, the research on lipids and their applications still present gaps about new sources as well as on the extraction methods. Filamentous fungi found in Antarctic territory could represent a new source of novel bioactive lipids. Currently Folch, Bligh & Dyer and Lewis methods are the most widely employed for extraction of lipid from different sample types. Nonetheless, choosing a single extraction method as the gold standard could represent a limitation, especially when the microorganism has not been studied yet. Taking the above into consideration, the main objective of the present study was to evaluate the best extraction method to obtain lipids from different Antarctic filamentous fungal genera. Material and methods: Three isolates of Antarctic fungi belonging to each genus: Mucor, Mortierella, Cladosporium, Penicillium and Pseudogymnoascus isolates from Fildes Bay, Antarctica, were evaluated. A total of 15 isolates were assessed. Folch, Bligh & Dyer and Lewis extraction method were performed. Extraction was monitored by recording spectra of FT-IR spectroscopy of the biomass before and after lipid extraction. Results: Folch was the best method to obtain lipids from filamentous Antarctic fungi, followed by Lewis extraction. Among the three extraction methods evaluated, Bligh & Dyer was the method that presented the lowest yield, compared to Folch and Lewis for each genus and strain. Strains of the genera Mortierella and Mucor were the ones that showed the best performance for the Folch and Lewis methods. The three Penicillium isolates were the third group with the best lipids yield for the Folch method. The strains of genera Cladosporium and Pseudogymnoascus showed better yields for the Lewis method. Conclusions: In this study it was observed that the lipids yield varies according to the extraction methods, as well as both the fungal isolate and fungal genus. Depending on the purpose and fungi taxa, to obtain lipids from Antarctic fungi Folch or Lewis extraction methods are recommended.info:eu-repo/semantics/publishedVersio

Characterisation of different Chilean Capsicum spp. varieties and the antifungal activity of their aqueous extracts

The increase in fungal resistance to synthetic antifungals used in agrifood production has brought the need to develop new technologies based on an eco-friendly approach. The main aim of this work was to evaluate the antifungal potential of Chilean Capsicum spp. extracts against plant pathogens and mycotoxigenic fungi found in agrifood production. Five different varieties of Chilean Capsicum spp. were obtained from both farmers and local markets in the city of Temuco, Chile. A specialist Botanist at the Universidad de La Frontera (Chile) confirmed the identification of pepper species and varieties. Fresh samples were grounded with a blender and freeze-dried for 7 days in the dark. After that, dry powder samples were stored at -20 °C in the dark until use. Pepper pod aqueous extracts were obtained by blending the freeze-dried puree from Capsicum spp. with 300 mL distilled water. Samples were incubated at 90°C for 20 minutes in a water bath with intermittent cycles of manual stirring every 2 minutes. The determination of capsaicinoid content was performed on an HPLC-FD system and the total polyphenols content was performed on an HPLC-DAD system. The antioxidant activity was carried out in a microplate reader using the DPPH and CUPRAC method. Reference strains of Alternaria, Aspergillus, Fusarium, Penicillium and Rhizopus were subjected to susceptibility tests (disc and culture media diffusion methods and MIC assay) against different concentrations of each pepper pod extract. Pure capsaicin, dihydrocapsaicin, nordihydrocapsaicin and amphotericin B were used as standard in the susceptibility tests. Significant differences in the concentration of capsaicinoids were found among the different varieties of the same Capsicum species. The pepper pod extracts affected the macro- and micro-morphological features of the analysed filamentous fungal strains. Fungal strains belonging to the genera Alternaria, Aspergillus, Fusarium, Penicillium and Rhizopus produced mycelium with thinning, fragile and easily-break structure. In addition, their conidiophores became fragile presenting easily-break structures. Regarding other fungal genera (data not shown), the main alteration was the absence of conidiophore formation in some strains. The morphological changes observed in the filamentous fungi strains suggest the fungistatic potential of pepper pod extracts. Results suggest pepper pod extracts could not kill non/target fungal biodiversity but could control the growth and reproduction of some fungal plant pathogens. Inhibition of mycotoxin production is now under evaluation. Additional work is being developed in the field to validate the in vitro results.ANID (Agencia Nacional de Investigación y Desarrollo, Chile) through the ANID/FONDECYT/1221024 project. This work was partially funded by the Universidad de La Frontera (Chile). Authors thank the InES19-FRO19001 project, funded by the Ministerio de Educación (Chile) and executed by the Universidad de La Frontera. The authors thank Professor Ruben Carrillo (UFRO) for his support in confirming the pepper species and varieties identification.info:eu-repo/semantics/publishedVersio