Nebulae in the Magellanic clouds

In this thesis I am primarily concerned with radio observations of the nebulae in the Magellanic Clouds, with particular emphasis on the regions of ionised gas in the Small Magellanic Cloud (SMC). Nebulae (Latin for ‘clouds’) are luminous fuzzy celestial objects with diverse size, shape and brightness. After several generations of observational and theoretical work, nebulae have been classified into four categories: external galaxies, H II regions, supernova remnants (SNRs) and planetary nebulae (PN). External galaxies are no longer regarded as true nebulae. H II regions are ionised hydrogen and are excited by the intense ultraviolet radiation of central or nearby hot stars. A planetary nebula is an extended, low density envelope which has expanded outward from a red giant star at a late stage in its evolution. SNRs are formed by the high velocity and high temperature material ejected when a star ends its life with a violent explosion. The current matters of interest in nebulae research concentrate on their classification and evolution, and their relation to the interstellar medium and to nucleosynthesis in their parent galaxies. Specifically, many investigations are directed toward the measurements of physical parameters such as electron temperature, density and elemental abundances, the morphologies of individual nebulae, spatial distributions of each type of nebula in galaxies, the number counts of sources within different luminosity ranges (the luminosity functions) and within different diameter ranges (diameter functions), the global absorption, scattering or reflection by dust (extinction) inside or outside of a nebula and the extinction distribution over a nebula

Nevirapine Plasma Concentrations Are Associated with Virologic Response and Hepatotoxicity in Chinese Patients with HIV Infection

BACKGROUND: Limited information is available on the relationship between nevirapine plasma concentrations and virologic response or liver toxicity in Chinese patients with HIV infection. The objective of this prospective study was to test this relationship and to determine the minimal therapeutic trough concentration of nevirapine for Chinese patients. METHODS: A total of 227 HIV-infected, treatment naïve patients were enrolled into this study. Blood samples were taken at C(trough) (12 hr postdose) and C(2) (2 hr postdose) for measurement of nevirapine concentrations 6 months after treatment initiation. Therapeutic outcomes, viral load and CD4 cell count, were assessed at 3 and 6 months after starting therapy, while the evaluation of hepatotoxicity was undertaken 12 months after nevirapine treatment. RESULTS: A significant correlation between nevirapine trough concentrations and viral load was noticed after 6 months of treatment, particularly in patients with partial response and viral failure (p<0.01). The therapeutic C(trough) of nevirapine for Chinese patients was determined to be 3.9 µg/ml using the receiver operating characteristic curve. Virologic failure was observed in 21% (6/29) of patients with low nevirapine concentrations (<3.9 µg/ml) versus 5% (4/87) in patients with concentrations higher than 3.9 µg/ml (p = 0.015). Hepatotoxicity was significantly associated with the median nevirapine trough concentrations among male patients (8.20 vs. 5.48 µg/ml, p = 0.015) and hepatitis C virus co-infection (p = 0.039). CONCLUSIONS: Among Chinese patients with HIV infection, the therapeutic C(trough) of nevirapine was 3.9 µg/ml, higher than the recommended 3.0 µg/ml. The correlation between nevirapine concentrations, efficacy and hepatotoxicity suggests the benefit of dosage adjustment based on therapeutic drug monitoring among Chinese HIV-infected patients to optimize nevirapine containing antiretroviral therapy

The Molonglo Galactic Plane Survey: I. Overview and Images

The first epoch Molonglo Galactic Plane Survey (MGPS1) is a radio continuum survey made using the Molonglo Observatory Synthesis Telescope (MOST) at 843 MHz with a resolution of 43" X 43" cosec |delta|. The region surveyed is 245 deg < l < 355 deg, |b| < 1.5 deg. The thirteen 9 deg X 3 deg mosaic images presented here are the superposition of over 450 complete synthesis observations, each taking 12 h and covering 70' X 70' cosec |delta|. The root-mean-square sensitivity over much of the mosaiced survey is 1-2 mJy/beam (1 sigma), and the positional accuracy is approximately 1" X 1" cosec |delta| for sources brighter than 20 mJy. The dynamic range is no better than 250:1, and this also constrains the sensitivity in some parts of the images. The survey area of 330 sq deg contains well over 12,000 unresolved or barely resolved objects, almost all of which are extra-galactic sources lying in the Zone of Avoidance. In addition a significant fraction of this area is covered by extended, diffuse emission associated with thermal complexes, discrete H II regions, supernova remnants, and other structures in the Galactic interstellar medium.Comment: Paper with 3 figures and 1 table + Table 2 + 7 jpg grayscales for Fig 4. Astrophysical Journal Supplement (in press) see also http://www.astrop.physics.usyd.edu.au/MGP

The Double Burdens of Mental Health Among AIDS Patients With Fully Successful Immune Restoration: A Cross-Sectional Study of Anxiety and Depression in China

Background: Anxiety and depression continue to be significant comorbidities for people with HIV infection. We investigated the prevalence of and factors associated with anxiety and depression among adult HIV-infected patients across China.Methods: In this cross-sectional study, we described clinical and psychosocial variables related to depression and anxiety in 4103 HIV-infected persons. Doctors assessed anxiety and depression by asking patients whether they had experienced anxiety or depression in the prior month. Patients also self-administered the Hospital Anxiety and Depression (HAD) scale; those with score ≥8 on HAD-A/D were considered to be at high risk of anxiety or depression.Results: Associations between socio-demographic, psychosocial, and ART-related clinical factors and risk of depression or anxiety were investigated using multivariable logistic regression. Among patients assessed between 9/2014 and 11/2015, 27.4% had symptoms of anxiety, 32.9% had symptoms of depression, and 19.0% had both. Recentness of HIV diagnoses (P = 0.046) was associated with elevated odds of anxiety. Older age (P = 0.004), higher educational attainment (P &lt; 0.001), employment (P = 0.001), support from family / friends (P &lt; 0.001), and sleep disturbance (P &lt; 0.001), and number of ART regimen switches (P = 0.046) were associated with risk of depression, while neither sex nor transmission route showed any associations. There were no significant associations with HIV-specific clinical factors including current CD4+ T cell count and current viral load.Conclusions: Prevalence of symptoms of anxiety and depression is high in this cohort of treatment-experienced HIV patients. Psychological and social-demographic factors, rather than HIV disease status, were associated with risk of depression and anxiety. This finding highlights the need to deliver interventions to address the mental health issues affecting HIV-infected persons with fully successful immune restoration across China

Comparison of Nevirapine Plasma Concentrations between Lead-In and Steady-State Periods in Chinese HIV-Infected Patients

<div><h3>Objectives</h3><p>To investigate the potential of nevirapine 200 mg once-daily regimen and evaluate the influence of patient characteristics on nevirapine concentrations.</p> <h3>Methods</h3><p>This was a prospective, multicentre cohort study with 532 HIV-infected patients receiving nevirapine as a part of their initial antiretroviral therapy. Plasma samples were collected at trough or peak time at the end of week 2 (lead-in period) and week 4, 12, 24, 36, and 48 (steady-state period), and nevirapine concentrations were determined using a validated HPLC method. Potential influencing factors associated with nevirapine concentrations were evaluated using univariate and multivariate logistic regression.</p> <h3>Results</h3><p>A total of 2348 nevirapine plasma concentrations were collected, including 1510 trough and 838 peak values. The median nevirapine trough and peak concentration during the lead-in period were 4.26 µg/mL (IQR 3.05–5.61) and 5.07 µg/mL (IQR 3.92–6.44) respectively, which both exceeded the recommended thresholds of nevirapine plasma concentrations. Baseline hepatic function had a moderate effect on median nevirapine trough concentrations at week 2 (4.25 µg/mL <em>v.s.</em> 4.86 µg/mL, for ALT <1.5×ULN and ≥1.5×ULN, respectively, <em>P</em> = 0.045). No significant difference was observed in median nevirapine trough concentration between lead-in and steady-state periods in patients with baseline ALT and AST level ≥1.5×ULN (<em>P</em> = 0.171, <em>P</em> = 0.769), which was different from the patients with ALT/AST level <1.5ULN. The median trough concentrations were significantly higher in HIV/HCV co-infected patients than those without HCV at week 48 (8.16 µg/mL <em>v.s.</em> 6.15 µg/mL, <em>P</em> = 0.004).</p> <h3>Conclusions</h3><p>The 200 mg once-daily regimen of nevirapine might be comparable to twice-daily in plasma pharmacokinetics in Chinese population. Hepatic function prior to nevirapine treatment and HIV/HCV coinfection were significantly associated with nevirapine concentrations.</p> <h3>Registration</h3><p>Clinicaltrial.gov ID: <a href="http://clinicaltrials.gov/ct2/show/NCT00872417">NCT00872417</a></p> </div