Microvascular endothelial injury and dysfunction during ischemic acute renal failure

Microvascular endothelial injury and dysfunction during ischemic acute renal failure. The pathophysiology of ischemic acute renal failure (ARF) appears to involve a complex interplay between renal hemodynamics, tubular injury, and inflammatory processes. While the current paradigm of the pathophysiology of ischemic ARF invokes both sublethal and lethal tubular injury as being of paramount importance to diminished renal function, a growing body of evidence supports the contribution of altered renal vascular function in potentially initiating and subsequently extending the initial tubular injury. We propose that the “extension phase” of ischemic ARF involves alterations in renal perfusion, continued hypoxia, and inflammatory processes that all contribute to continued tubular cell injury. Vascular endothelial cell injury and dysfunction play a vital part in this extension phase. In the constitutive state the endothelium regulates migration of inflammatory cells into tissue, vascular tone and perfusion, vasopermeability, and prevents coagulation. Upon injury, the endothelial cell loses its ability to regulate these functions. This loss of regulatory function can have a subsequent detrimental impact upon renal function. Vascular congestion, edema formation, diminished blood flow, and infiltration of inflammatory cells have been documented in the corticomedullary junction of the kidney, but linking their genesis to vascular endothelial injury and dysfunction has been difficult. However, new investigative approaches, including multiphoton microscopy and the Tie2-GFP mouse, have been developed that will further our understanding of the roles endothelial injury and dysfunction play in the pathophysiology of ischemic ARF. This knowledge should provide new diagnostic and therapeutic approaches to ischemic ARF

Fitting density models to observational data - The local Schmidt law in molecular clouds

We consider the general problem of fitting a parametric density model to discrete observations, taken to follow a non-homogeneous Poisson point process. This class of models is very common, and can be used to describe many astrophysical processes, including the distribution of protostars in molecular clouds. We give the expression for the likelihood of a given spatial density distribution of protostars and apply it to infer the most probable dependence of the protostellar surface density on the gas surface density. Finally, we apply this general technique to model the distribution of protostars in the Orion molecular cloud and robustly derive the local star formation scaling (Schmidt) law for a molecular cloud. We find that in this cloud the protostellar surface density, $\Sigma_\mathrm{YSO}$, is directly proportional to the square gas column density, here expressed as infrared extinction in the $K$-band, $A_K$: more precisely, $\Sigma_\mathrm{YSO} = (1.65 \pm 0.19) A_K^{(2.03 \pm 0.15)}$ stars pc$^{-2}$.Comment: 6 pages, A&A in press. References fixe

AUTOMATING SOFTWARE DEVELOPMENT PRODUCTIVITY METRICS

Measurement of software development productivity is needed in order to control software costs, but it is discouragingly labor-intensive and expensive. Computer aided software engineering (CASE) technologies -- especially object-oriented, integrated CASE -- have the potential to support the automation of this measurement. In this paper, we describe automated analyzers for function point and code reuse measurement. Both analyzers take advantage of the existence of a meta-model of the application system, stored within an object repository, which contains the necessary information about the application system. We also propose new metrics for code reuse analysis, including reuse leverage, reuse value and reuse classification. The state-of-the-art automated software metrics analyzers are illustrated in the context of an investment banking industry application.Information Systems Working Papers Serie

Re\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e7\u3c/sub\u3e-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles

Re(VII) oxides catalyze the acetalization, monoperoxyacetalization, monothioacetalization and allylation of hemiacetals. The reactions, which take place under mild conditions and at low catalyst loadings, can be conducted using hemiacetals, the corresponding O-silyl ethers, and, in some cases, the acetal dimers. Aldehydes react under similar conditions to furnish good yields of dithioacetals. Reactions of hemiacetals with nitrogen nucleophiles are unsuccessful. 1,2-Dioxolan-3-ols (peroxyhemiacetals) undergo Re(VII)-promoted etherification but not allylation. Hydroperoxyacetals (1-alkoxyhydroperoxides) undergo selective exchange of the alkoxide group in the presence of either Re2O7 or a Brønsted acid

Re\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e7\u3c/sub\u3e-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles

Re(VII) oxides catalyze the acetalization, monoperoxyacetalization, monothioacetalization and allylation of hemiacetals. The reactions, which take place under mild conditions and at low catalyst loadings, can be conducted using hemiacetals, the corresponding O-silyl ethers, and, in some cases, the acetal dimers. Aldehydes react under similar conditions to furnish good yields of dithioacetals. Reactions of hemiacetals with nitrogen nucleophiles are unsuccessful. 1,2-Dioxolan-3-ols (peroxyhemiacetals) undergo Re(VII)-promoted etherification but not allylation. Hydroperoxyacetals (1-alkoxyhydroperoxides) undergo selective exchange of the alkoxide group in the presence of either Re2O7 or a Brønsted acid

A dust disk surrounding the young A star HR4796A

We report the codiscovery of the spatially-resolved dust disk of the Vega-like star HR 4796A. Images of the thermal dust emission at $\lambda = 18 \mu$m show an elongated structure approximately 200 AU in diameter surrounding the central A0V star. The position angle of the disk, $30^{\circ} \pm 10^{\circ}$, is consistent to the position angle of the M companion star, $225^{\circ}$, suggesting that the disk-binary system is being seen nearly along its orbital plane. The surface brightness distribution of the disk is consistent with the presence of an inner disk hole of approximately 50 AU radius, as was originally suggested by Jura et al. on the basis of the infrared spectrum. HR 4796 is a unique system among the Vega-like or $\beta$ Pictoris stars in that the M star companion (a weak-emission T Tauri star) shows that the system is relatively young, $\sim 8 \pm 3$ Myr. The inner disk hole may provide evidence for coagulation of dust into larger bodies on a timescale similar to that suggested for planet formation in the solar system.Comment: 12 pages, 3 PostScript figures, accepted for publication in Astrophysical Journal Letter

The Safety Profile of Intentional or Iatrogenic Sacrifice of the Artery of Adamkiewciz and Its Vicinity’s Spinal Segmental Arteries: A Systematic Review

Study Design: Systematic review. Objectives: There is paucity of consensus on whether (1) the artery of Adamkiewicz (AoA) and (2) the number of contiguous segmental spinal arteries (SSAs) that can be safely ligated without causing spinal cord ischemia. The objective of this review is to determine the risk of motor neurological deficits from iatrogenic sacrifice of the (1) AoA and (2) its vicinity’s SSAs. Methods: Systematic review of the spine and vascular surgery was carried out in accordance to PRISMA guidelines. Outcomes in terms of risk of postoperative motor neurological deficit with occlusion of the AoA, bilateral contiguous SSAs, or unilateral contiguous SSAs were analyzed. Results: Ten articles, all retrospective case series, were included. Three studies (total N = 50) demonstrated a postoperative neurological deficit risk of 4.0% when the AoA is occluded. When 1 to 6 pairs of SSAs (without knowledge of AoA location) were ligated, the postoperative neurological deficit risk was 0.6%, as compared with 5.4% when more than 6 bilateral pairs of SSAs were ligated (relative risk [RR] = 0.105, 95% CI 0.013-0.841, P =.0337). For unilateral ligation of SSAs of two to nine levels, the risk of postoperative neurological deficit does not exceed 1.3%. Conclusion: The current best evidence indicates that (1) occlusion of the AoA and (2) occlusion of up to 6 pairs of SSAs is associated with a low risk of postoperative neurological deficit. This limited number of low quality studies restrict the ability to draw definitive conclusions. Ligation of AoA and SSAs should only be undertaken when absolutely required to mitigate the small but devastating risk of paralysis