Intraoperative blood salvage in children and young adults undergoing spinal surgery with predeposited autologous blood: efficacy and cost effectiveness

We conducted a retrospective review of 155 spinal operations at our institution to determine the efficacy of intraoperative salvage. Addition of intraoperative salvage had little effect on the success of a preoperative autologous donation program. Only patients with operative blood loss > 2,000 ml (12% of patients) benefited from this expensive source of autologous blood. The technique tended to be most effective in children aged 16-18 years. Use of intraoperative salvage for all pediatric spinal procedures is neither necessary nor cost effective.     

Double-diffusive convection in a circular cylinder

Summary A theoretical study is made of the onset of steady double-diffusive convection in a circular cylinder of small to moderate aspect ratio. An eigenfunction expansion method is used to derive systems of amplitude equations for weakly nonlinear evolution of critical disturbances. It is shown that the nature of the convective solution near criticality depends strongly on the cylinder's aspect ratio; this is particularly the case at or near aspect ratios where two modes become unstable at the same Rayleigh number. There is also a strong dependence on Prandtl number, which is discussed.With 7 Figure     

A model for the dc electrical behavior of bulk-barrier diodes

Contents  This paper presents an analytical model for the dc electrical behavior of bulk barrier diodes (BBD's). The proposed model extends previously published models, and includes analytical expressions for all significant quantities of the device dc performance, i.e. barrier height, current density and ideality factor, with respect to the technological parameters and the applied voltage in both bias conditions. The analytical results have been compared with those obtained using the 2-D device simulator S-PISCES, which takes into account the drift–diffusion theory, as well as a concentration and field dependent mobility, the Shockley–Read–Hall and Auger carrier recombination, and the band gab narrowing. Good agreement was obtained between theory and simulation. The device simulation played a very important role in best understanding BBD's behavior, because it could easily take into account parameters strongly affecting the behavior of BBD's, e.g. the free carrier presence in depletion layers, which was very difficult for the analytical model to include. Received: 15 January 2001     

Dynamic response of reinforced masonry columns in classical monuments

From the mechanical point of view, the particularity of masonry structures stems from the fact that the structural system is hard to be modeled by the classical Continuum Mechanics approach. The problem gets more complicated when imperfections, such as cracks are present. An example of a single multi-drum column, with fractured drums, is studied herein, using the Distinct Element Method (DEM). The purpose of the research is the investigation of the impact of the fractures to the overall stability of the structure. The 3D DEM numerical results are explained on the basis of simple 2D analytical considerations. The shear and normal crack deformation is monitored and the minimum required strength of the crack interface is quantified. An experimental program of direct shear tests is set in order to estimate the strength of the marble–cement interface. The experimental values are compared to the minimum required from the numerical analysis.     

Stochastic response surface methods (SRSMs) for uncertainty propagation: application to environmental and biological systems

Indicators of self-efficacy and motivation to change (stage of change) with regard to drinking and to drinking and driving were examined in a sample of Driving Under the Influence (DUI) offenders in a court-mandated intervention program. Self-administered questionnaires that contained pertinent measures were completed by 210 consenting offenders (34 of whom were female) during the intervention program. A factor analysis of efficacy and stages of change items showed distinct factors for the respective constructs; however, drinking and drinking-and-driving items of the same type (e.g., efficacy or stages of change) tended to codefine common factors, and the factor pattern suggested that motivations and efficacy for changing drinking behavior are critical for avoiding the drinking-and-driving sequence. Most participants were classified into the action stage in both drinking and drinking-and-driving domains. In regression analysis, contemplation of action and self-efficacy measures pertaining to drinking and driving predicted prior crashes and arrests; however, after accounting for recent alcohol problems, action items pertaining to drinking and driving were the best predictors of recent drinking-and-driving incidents.     

Both the Escherichia coli chaperone systems, GroEL/GroES and DnaK/DnaJ/GrpE, can reactivate heat-treated RNA polymerase. Different mechanisms for the same activity

In this work we show that the GroEL (Hsp60 equivalent) chaperone protein can protected purified Escherichia coli RNA polymerase (RNAP) holoenzyme from heat inactivation better than the DnaK (Hsp70 equivalent) chaperone can. In this protection reaction, the GroES protein is not essential, but its presence reduces the amount of GroEL required. GroEL and GroES can also reactivate heat-inactivated RNAP in the presence of ATP. The mutant GroEL673 protein, with or without GroES, is incapable of reactivating heat-inactivated RNAP. GroEL673 can only protect RNAP, and this protecting ability is not stimulated by GroES. The mechanism by which the DnaJ and GrpE heat shock proteins contribute to DnaK's ability to reactivate heat-inactivated RNAP GroEL673 has also been investigated. We found that the DnaJ protein substantially reduces the levels of DnaK protein needed in this reactivation assay. However, the observed lag in reactivation is diminished only in the additional presence of the GrpE protein. Hence, DnaJ and GrpE are involved in both steps of this reactivation reaction (recognition of substrate and release of chaperone from the substrate-chaperone complex) while, in the case of the GroEL-dependent reaction, GroES is involved only during the release of chaperone from the substrate-chaperone complex.     

ApoA1 Deficiency Reshapes the Phenotypic and Molecular Characteristics of Bone Marrow Adipocytes in Mice

In the present study, we studied the effect of apolipoprotein A-1 (APOA1) on the spatial and molecular characteristics of bone marrow adipocytes, using well-characterized ApoA1 knockout mice. APOA1 is a central regulator of high-density lipoprotein cholesterol (HDL-C) metabolism, and thus HDL; our recent work showed that deficiency of APOA1 increases bone marrow adiposity in mice. We found that ApoA1 deficient mice have greatly elevated adipocytes within their bone marrow compared to wild type counterparts. Morphologically, the increased adipocytes were similar to white adipocytes, and displayed proximal tibial-end localization. Marrow adipocytes from wild type mice were significantly fewer and did not display a bone-end distribution pattern. The mRNA levels of the brown/beige adipocyte-specific markers Ucp1, Dio2, Pat2, and Pgc1a; and the expression of leptin were greatly reduced in the ApoA1 knock-out in comparison to the wild-type mice. In the knock-out mice, adiponectin was remarkably elevated. In keeping with the close ties of hematopoietic stem cells and marrow adipocytes, using flow cytometry we found that the elevated adiposity in the ApoA1 knockout mice is associated with a significant reduction in the compartments of hematopoietic stem cells and common myeloid, but not of the common lymphoid, progenitors. Moreover, the ‘beiging’-related marker osteopontin and the angiogenic factor VEGF were also reduced in the ApoA1 knock-out mice, further supporting the notion that APOA1—and most probably HDL-C—regulate bone marrow microenvironment, favoring beige/brown adipocyte characteristics.     

Transgenic and knockout analyses of the role of TNF in immune regulation and disease pathogenesis

Transgenic mutagenesis in whole animals has become without doubt the most rewarding approach to analyse gene structure, expression, and function. In the TNF field, much of what we now question about TNF/TNF receptor function is based, to a large extent, on what we have already learned by overexpressing these molecules in transgenic mice or by ablating their expression in knockout systems. In addition, a clearer view of the involvement of these molecules in disease pathogenesis has emerged, and useful models for human disease have been generated. In this overview, we summarise our experience with TNF transgenic and knockout systems, and highlight advances made in our understanding of the role played by TNF and its receptors in immune regulation and in the pathogenesis of infectious, inflammatory, and autoimmune disease.     

Slow solidification of a cylinder with constant heat efflux

An asymptotic solution for the slow solidification of an infinite cylinder with constant surface heat flux is presented. The solidification of a 10 cm. diameter aluminum cylinder in 30 minutes corresponds to a value of 0.00901 for the small parameter. The predictions of the solidification front position based on the first three terms in the asymptotic expansion are presented. The extension to steady-state continuous casting is discussed.     

Endothelial cell compatibility of glycopeptide antibiotics for intravenous use

OBJECTIVE: The aim of this study was to evaluate the pulmonary CT findings in patients with Churg-Strauss syndrome to determine the frequency and nature of parenchymal abnormalities. MATERIALS AND METHODS: CT examinations performed at the time of diagnosis in 17 patients with Churg-Strauss syndrome were retrospectively evaluated by two observers who reached a decision by consensus about the presence and nature of parenchymal abnormalities. High-resolution CT (1- to 3-mm collimation) was performed in 14 patients and conventional CT (6- to 10-mm collimation) was performed in three cases. RESULTS: Predominant CT findings consisted of parenchymal opacification (consolidation or ground-glass attenuation) (n = 10), pulmonary nodules (n = 2), bronchial wall thickening or dilatation (n = 2), interlobular septal thickening (n = 1), and normal anatomy (n = 2). Parenchymal opacification was predominantly peripheral (n = 6) or random in distribution (n = 4). CONCLUSION: The most common CT finding in patients with Churg-Strauss syndrome consists of areas of parenchymal opacification that may be random or peripheral in distribution. These findings are nonspecific.