14 research outputs found

    A review of elliptical and disc galaxy structure, and modern scaling laws

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    A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

    Systems biology analysis of drivers underlying hallmarks of cancer cell metabolism

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    Malignant transformation is often accompanied by significant metabolic changes. To identify drivers underlying these changes, we calculated metabolic flux states for the NCI60 cell line collection and correlated the variance between metabolic states of these lines with their other properties. The analysis revealed a remarkably consistent structure underlying high flux metabolism. The three primary uptake pathways, glucose, glutamine and serine, are each characterized by three features: (1) metabolite uptake sufficient for the stoichiometric requirement to sustain observed growth, (2) overflow metabolism, which scales with excess nutrient uptake over the basal growth requirement, and (3) redox production, which also scales with nutrient uptake but greatly exceeds the requirement for growth. We discovered that resistance to chemotherapeutic drugs in these lines broadly correlates with the amount of glucose uptake. These results support an interpretation of the Warburg effect and glutamine addiction as features of a growth state that provides resistance to metabolic stress through excess redox and energy production. Furthermore, overflow metabolism observed may indicate that mitochondrial catabolic capacity is a key constraint setting an upper limit on the rate of cofactor production possible. These results provide a greater context within which the metabolic alterations in cancer can be understood

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    Verteporfin therapy of subfoveal choroidal neovascularization in age-related macular degeneration: Two-year results of a randomized clinical trial including lesions with occult with no classic choroidal neovascularization-verteporfin in photodynamic therapy report 2

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    PURPOSE: To determine if photodynamic therapy with verteporfin (Visudyne; Novartis AG, Bulach, Switzerland), termed verteporfin therapy, can safely reduce the risk of vision loss compared with a placebo (with sham treatment) in patients with subfoveal choroidal neovascularization caused by age-related macular degeneration who were identified with a lesion composed of occult with no classic choroidal neovascularization, or with presumed early onset classic choroidal neovascularization with good visual acuity letter score, METHODS: This was a double-masked, placebo controlled (sham treatment), randomized, multicenter clinical trial involving 28 ophthalmology practices in Europe and North America. The study population was patients with age related macular degeneration, with subfoveal choroidal neovascularization lesions measuring no greater than 5400 mum in greatest linear dimension with either 1) occult with no classic choroidal neovascularization, best-corrected visual acuity score of at least 50 (Snellen equivalent approximately 20/100), and evidence of hemorrhage or recent disease progression; or 2) evidence of classic choroidal neovascularization with a best-corrected visual acuity score of at least 70 (better than a Snellen equivalent of approximately 20/40); assigned randomly (2:1) to verteporfin therapy or placebo therapy. Verteporfin (6 mg per square meter of body surface area) or placebo (5% dextrose in water) was administered by means of intravenous infusion of 30 mi over 10 minutes. Fifteen minutes after the start of the infusion, a laser light at 689 nm delivered 50 J/cm(2) by application of an intensity of 600 mW/cm(2) over 83 seconds using a spot size with a diameter 1000 mum larger than the greatest linear dimension of the choroidal neovascularization lesion on the retina. At follow-up examinations every 3 months, retreatment with the same regimen was applied if angiography showed fluorescein leakage. The main outcome measure was at least moderate vision loss, that is, a loss of at least 15 letters (approximately 3 lines), adhering to an intent-to treat analysis with the last observation carried forward to impute for missing data. RESULTS: Two hundred ten (93%) and 193 (86%) of the 225 patients in the verteporfin group compared with 104 (91%) and 99 (87%) of the 114 patients in the placebo group completed the month 12 and 24 examinations, respectively. On average, verteporfin-treated patients received five treatments over the 24 months of follow-up. The primary outcome was similar for the verteporfin-treated and the placebo-treated eyes through the month 12 examination, although a number of secondary visual and angiographic outcomes significantly favored the verteporfin-treated group. Between the month 12 and 24 examinations, the treatment benefit grew so that by the month 24 examination, the vertepor-fin-treated eyes were less likely to have moderate or severe vision loss. Of the 225 verteporfin-treated patients, 121 (54%) compared with 76 (67%) of 114 placebo-treated patients lost at least 15 letters (P =.023). Likewise, 61 of the verteporfin-treated patients (30%) compared with 54 of the placebo-treated patients (47%) lost at least 30 letters (P = .001). Statistically significant results favoring verteporfin therapy at the month 24 examination were consistent between the total population and the subgroup of patients with a baseline lesion composition identified as occult choroidal neovascularization with no classic choroidal neovascularization, This subgroup included 166 of the 225 verteporfin-treated patients (74%) and 92 of the 114 placebo-treated patients (81%). In these patients, 91 of the verteporfin-treated group (55%) compared with 63 of the placebo-treated group (68%) lost at least 15 letters (P =.032), whereas 48 of the verteporfin-treated group (29%) and 43 of the placebo-treated group (47%) lost at least 30 letters (P =.004). Other secondary outcomes, including visual acuity letter score worse than 34 (approximate Snellen equivalent of 20/200 or worse), mean change in visual acuity letter score, development of classic choroidal neovascularization, progression of classic choroidal neovascularization and size of lesion, favored the verteporfin-treated group at both the month 12 and month 24 examination for both the entire study group and the subgroup of cases with occult with no classic choroidal neovascularization at baseline. Subgroup analyses of lesions composed of occult with no classic choroidal neovascularization at baseline suggested that the treatment benefit was greater for patients with either smaller lesions (4 disc areas or less) or lower levels of visual acuity (letter score less than 65, an approximate Snellen equivalent of 20/50(-1) or worse) at baseline. Prospectively planned multivariable analyses confirmed that these two baseline variables affected the magnitude of treatment benefit. Of the 123 verteporfin-treated patients and 64 placebo-heated patients with either visual acuity score Less than 65 or lesion size 4 disc areas or less at baseline, 60 (49%) and 48 (75%) lost at least 15 letters (P 2001 by Elsevier Science Inc. All rights reserved.)
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