5 research outputs found

    6.7 GHz variability characteristics of new periodic methanol maser sources

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    Discovery of periodic maser emission was an unexpected result from monitoring observations of methanol transitions in high-mass young stellar objects. We report on the detection of five new periodic sources from a monitoring program with the Torun 32 m telescope. Variability with a period of 149 to 540 d and different patterns from sinusoidal-like to intermittent was displayed. Three-dimensional structure of G59.633−0.192 determined from the time delays of burst peaks of the spectral features and high angular resolution map implies that the emission traces a disc. For this source the 6.7 GHz light curve followed the infrared variability supporting a radiative scheme of pumping. An unusual time delay of ∼80 d occurred in G30.400−0.296 could not be explained by the light travel time and may suggest a strong differentiation of physical conditions and excitation in this deeply embedded source. Our observations suggest the intermittent variability may present a simple response of maser medium to the underlying variability induced by the accretion luminosity while other variability patterns may reflect more complex changes in the physical conditions

    Monitoring observations of 6.7 GHz methanol masers

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    We report results of 6.7 GHz methanol maser monitoring of 139 star-forming sites with theTorun 32 m radio telescope from June 2009 to February 2013. The targets were observedat least once a month, with higher cadences of 2-4 measurements per week for circumpolarobjects. Nearly 80 per cent of the sources display variability greater than 10 per cent on atime-scale between a week and a few years but about three quarters of the sample have only1-3 spectral features which vary significantly. Irregular intensity fluctuation is the dominanttype of variability and only nine objects show evidence for cyclic variations with periodsof 120 to 416 d. Synchronised and anti-correlated variations of maser features are detectedin four sources with a disc-like morphology. Rapid and high amplitude bursts of individualfeatures are seen on 3-5 occasions in five sources. Long (>50 d to 20 months) lasting burstsare observed mostly for individual or groups of features in 19 sources and only one sourceexperienced a remarkable global flare. A few flaring features display a strong anti-correlationbetween intensity and line-width that is expected for unsaturated amplification. There is aweak anti-correlation between the maser feature luminosity and variability measure, i.e. maserfeatures with low luminosity tend to be more variable than those with high luminosity. Theanalysis of the spectral energy distribution and continuum radio emission reveals that thevariability of the maser features increases when the bolometric luminosity and Lyman fluxof the exciting object decreases. Our results support the concept of a major role for infraredpumping photons in triggering outburst activity of maser emission

    A retrospective evaluation of associations between chronic obstructive pulmonary disease, smoking, and efficacy of chemotherapy and selected laboratory parameters in patients with advanced non-small cell lung cancer

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    Aim of the study: To was to determine the impact of chronic obstructive pulmonary disease (COPD) and active smoking on the efficacy of chemotherapy and complete blood count (CBC) in patients with non-small cell lung cancer (NSCLC). Material and methods: The retrospective evaluation included 50 patients with stage IIIB–IV NSCLC, who started cisplatin-based chemotherapy. Peripheral blood CBC values were collected for testing before chemotherapy and after the first and third cycles. Results : COPD was diagnosed in 49% of patients, while 42% of those enrolled were current smokers. Current smoking (p = 0.92) and COPD (p = 0.91) status did not affect the response to treatment. The non-COPD population presented a significantly higher pretreatment absolute lymphocyte count (ALC) than the COPD population (2.31 vs. 1.81 × 109/l; p = 0.0374). Also, only the non-COPD group demonstrated an elevated absolute monocyte count (AMC) following the first and third cycles of chemotherapy (p = 0.004). In current smokers, pretreatment values for white blood cells (WBC), absolute neutrophil count (ANC), and platelets (PLT) were higher than in the ex-smoker population (WBC 9.94 vs. 8.7 (× 109/l); p = 0.01; ANC 6.47 vs. 5.61 (× 109/l); p = 0.037; PLT 316 vs. 266 (× 109/l); p = 0.049). Ex-smokers demonstrated AMC level elevation after the first cycle of chemotherapy and PLT level elevation after the third cycle, while current smokers also demonstrated an early decrease in LMR. Conclusions : COPD and smoking induce chronic systemic inflammation and oxidative stress, which influence the results of standard laboratory tests, but do not change the response rate of lung cancer on chemotherapy

    Kidney Transplant Recipients Show Limited Lung Diffusion Capacity but Similar Hydrogen Peroxide Exhalation as Healthy Matched Volunteers: A Pilot Study

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    Patients with end-stage chronic kidney disease show higher systemic oxidative stress and exhale more hydrogen peroxide (H2O2) than healthy controls. Kidney transplantation reduces oxidative stress and H2O2 production by blood polymorphonuclear leukocytes (PMNs). Kidney transplant recipients (KTRs) may be predisposed to an impairment of lung diffusing capacity due to chronic inflammation. Lung function and H2O2 concentration in the exhaled breath condensate (EBC) were compared in 20 KTRs with stable allograft function to 20 healthy matched controls. Serum interleukin eight (IL-8) and C-reactive protein (CRP), blood cell counts, and spirometry parameters did not differ between groups. However, KTRs showed lower total lung diffusing capacity for carbon monoxide, corrected for hemoglobin concentration (TLCOc), in comparison to healthy controls (92.1 ± 11.5% vs. 102.3 ± 11.9% of predicted, p = 0.009), but similar EBC H2O2 concentration (1.63 ± 0.52 vs. 1.77 ± 0.50 µmol/L, p = 0.30). The modality of pre-transplant renal replacement therapy had no effect on TLCOc and EBC H2O2. TLCOc did not correlate with time after transplantation. In this study, TLCOc was less reduced in KTRs in comparison to previous reports. We suggest this fact and the non-elevated H2O2 exhalation exhibited by KTRs, may result perhaps from the evolution of the immunosuppressive therapy
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