The 3-Dimensional Distribution of Dust in NGC 891

We produce three-dimensional Monte-Carlo radiative transfer models of the edge-on spiral galaxy NGC 891, a fast-rotating galaxy thought to be an analogue to the Milky Way. The models contain realistic spiral arms and a fractal distribution of clumpy dust. We fit our models to Hubble Space Telescope images corresponding to the B and I bands, using shapelet analysis and a genetic algorithm to generate 30 statistically best-fitting models. These models have a strong preference for spirality and clumpiness, with average face-on attenuation decreasing from 0.24(0.16) to 0.03(0.03) mag in the B(I) band between 0.5 and 2 radial scale-lengths. Most of the attenuation comes from small high-density clumps with low (<10%) filling factors. The fraction of dust in clumps is broadly consistent with results from fitting NGC 891's spectral energy distribution. Because of scattering effects and the intermixed nature of the dust and starlight, attenuation is smaller and less wavelength-dependent than the integrated dust column-density. Our clumpy models typically have higher attenuation at low inclinations than previous radiative transfer models using smooth distributions of stars and dust, but similar attenuation at inclinations above 70 degrees. At all inclinations most clumpy models have less attenuation than expected from previous estimates based on minimizing scatter in the Tully-Fisher relation. Mass-to-light ratios are higher and the intrinsic scatter in the Tully-Fisher relation is larger than previously expected for galaxies similar to NGC 891. The attenuation curve changes as a function of inclination, with R_(B,B-I)=A_(B)/E(B-I) increasing by ~0.75 from face-on to near-edge-on orientations.Comment: 26 pages, 18 figures, accepted for publication in Ap

The 3-Dimensional Structure of NGC 891 and M51

We investigate the three-dimensional structure of the nearby edge-on spiral galaxy NGC 891 using 3D Monte Carlo radiative transfer models, with realistic spiral structure and fractally clumped dust. Using the spiral and clumpiness parameters found from recently completed scattered light models we produce lower resolution SED models which reproduce the global UV-to-FIR SED of NGC 891. Our models contain a color gradient across the major axis of the galaxy - similar to what is seen in images of the NGC 891. With minor adjustment our SED models are able to match the majority of M51's SED, a similar galaxy at a near face-on different inclination.Comment: 3 pages, 1 figure. To appear in the Conference Proceedings of IAU Symposium No. 284: The Spectral Energy Distribution of Galaxies, R.J. Tuffs & C.C. Popescu, ed

Atherosclerosis of the ascending aorta is a predictor of renal dysfunction after cardiac operations

AbstractObjectives: Renal dysfunction occurring after cardiac operations has been attributed to various factors, but the importance of an atherosclerotic thoracic aorta has not been previously evaluated. The purpose of this study was to identify predictors of postoperative renal dysfunction (50% or more increase from preoperative values) and to evaluate the importance of atherosclerosis of the ascending aorta as a predictor of this complication. Methods: Nine hundred seventy-eight consecutive patients, 50 years of age and older with normal preoperative renal function (serum creatinine level of 1.5 mg/dL or less), who were scheduled to undergo cardiac surgery were prospectively evaluated. Atherosclerosis of the ascending aorta was assessed during the operation (with epiaortic ultrasound), and patients were divided into 3 groups according to its severity (normal-to-mild, moderate, and severe). Results: Univariate predictors of renal dysfunction at postoperative day 1 were atherosclerosis of the ascending aorta (P < .045) and postoperative low cardiac output (P = .05); at postoperative day 6 they were atherosclerosis of the ascending aorta (P < .0001), postoperative low cardiac output (P < .0001), advanced age (P = .001), decreased preoperative left ventricular function (P = .01), and female gender (P = .03). Multivariate analysis showed that atherosclerosis of the ascending aorta (odds ratio, 3.06; P = .04) was the only independent predictor of postoperative renal dysfunction at day 1 and that postoperative low cardiac output (odds ratio, 4.83; P < .0001), atherosclerosis of the ascending aorta (odds ratio, 2.13; P = .0006), and preoperative left ventricular dysfunction (odds ratio, 1.48; P = .028) were independent predictors of postoperative renal dysfunction at day 6. Conclusions: An atherosclerotic ascending aorta is an important predictor of postoperative renal dysfunction, possibly because atheroembolism to the kidneys occurs in the perioperative period (ie, during surgical manipulation of an atherosclerotic aorta) or because the diseased aorta may be a marker of widespread atherosclerotic disease that may predispose to perioperative renal dysfunction. (J Thorac Cardiovasc Surg 1999;117:111-6

Atherosclerosis of the ascending aorta is an independent predictor of long-term neurologic events and mortality

AbstractOBJECTIVESThis study was undertaken to determine whether atherosclerosis of the ascending aorta is a predictor of long-term neurologic events and mortality.BACKGROUNDAtherosclerosis of the thoracic aorta has been recently considered a significant predictor of neurologic events and peripheral embolism, but not of long-term mortality.METHODSLong-term follow-up (a total of 5,859 person-years) was conducted of 1,957 consecutive patients ≥50 years old who underwent cardiac surgery. Atherosclerosis of the ascending aorta was assessed intraoperatively (epiaortic ultrasound) and patients were divided into four groups according to severity (normal, mild, moderate or severe). Carotid artery disease was evaluated (carotid ultrasound) in 1,467 (75%) patients. Cox proportional-hazards regression analysis was performed to assess the independent effect of predictors on neurologic events and mortality.RESULTSA total of 491 events occurred in 472 patients (neurologic events 92, all-cause mortality 399). Independent predictors of long-term neurologic events were: hypertension (p = 0.009), ascending aorta atherosclerosis (p = 0.011) and diabetes mellitus (p = 0.015). The independent predictors of mortality were advanced age (p < 0.0001), left ventricular dysfunction (p < 0.0001), ascending aorta atherosclerosis (p < 0.0001), hypertension (p = 0.0001) and diabetes mellitus (p = 0.0002). There was >1.5-fold increase in the incidence of both neurologic events and mortality as the severity of atherosclerosis increased from normal-mild to moderate, and a greater than threefold increase in the incidence of both as the severity of atherosclerosis increased from normal-mild to severe.CONCLUSIONSAtherosclerosis of the ascending aorta is an independent predictor of long-term neurologic events and mortality. These results provide additional evidence that in addition to being a direct cause of cerebral atheroembolism, an atherosclerotic ascending aorta may be a marker of generalized atherosclerosis and thus of increased morbidity and mortality

Recombinant human perlecan DV and its LG3 subdomain are neuroprotective and acutely functionally restorative in severe experimental ischemic stroke

Despite recent therapeutic advancements, ischemic stroke remains a major cause of death and disability. It has been previously demonstrated that  ~ 85-kDa recombinant human perlecan domain V (rhPDV) binds to upregulated integrin receptors (α2β1 and α5β1) associated with neuroprotective and functional improvements in various animal models of acute ischemic stroke. Recombinant human perlecan laminin-like globular domain 3 (rhPD