Biomimetic acellular detoxified glutaraldehyde cross-linked bovine pericardium for tissue engineering

Glutaraldehyde (GLUT) processing, cellular antigens, calcium ions in circulation, and phospholipids present in the native tissue are predominantly responsible for calcification, degeneration, and lack of natural microenvironment for host progenitor cell migration in tissue implants. The study presents an improved methodology for adhesion and proliferation of endothelial progenitor cells (EPCs) without significant changes in biomechanical and biodegradation properties of the processed acellular bovine pericardium. The anti-calcification potential of the processed tissue was enhanced by detoxification of GLUT-cross-linked bovine pericardium by decellularization, pretreating it with ethanol or removing the free aldehydes by citric acid treatment and lyophilization. The treated tissues were assessed for biomechanical properties, GLUT ligand quantification, adhesion, proliferation of EPCs, and biodegradability. The results indicate that there was no significant change in biomechanical properties and biodegradability when enzymatic hydrolysis (p > 0.05) is employed in detoxified acellular GLUT cross-linked tissue (DBP–G–CA–ET), compared with the native detoxified GLUT cross-linked bovine pericardium (NBP–G–CA–ET). DBP–G–CA–ET exhibited a significant (p > 0.05) increase in the viability of EPCs and cell adhesion as compared to acellular GLUT cross-linked bovine pericardium (p < 0.05). Lyophilized acellular detoxified GLUT cross-linked bovine pericardium, employed in our study as an alternative to conventional GLUT cross-linked bovine pericardium, might provide longer durability and better biocompatibility, and reduce calcification. The developed bovine pericardium patches could be used in cardiac reconstruction and repair, arteriotomy, soft tissue repair, and general surgical procedures with tissue regeneration dimensions.     

Incidence of intermediate syndrome in organophosphorous poisoning

Seventy two patients admitted to the Intensive Care Unit following ingestion of organophosphorus compounds were studied prospectively with two different doses of pralidoxime (PAM). One group received 1 gm immediately after admission and no further PAM and the other group received infusion of PAM, 1 gm 8 hourly for four days (total 12 gms). The incidence of type II paralysis or intermediate syndrome was 47%. We observed a higher incidence in the 4 days of infusion of PAM group (61%) (20 patients) as compared to the single Bolus dose group (39%) (13 patients). Relative risk 1.48 (confidence interval = 0.9-2.4).     

Rheological behavior of nanocomposites of natural rubber and carboxylated styrene butadiene rubber latices and their blends

Flow behavior of latices is industrially important for the manufacturing of various latex goods. Rheology of latices having fillers can assist in the understanding and quantification of the matrix–filler interaction. The impact of layered silicates such as sodium bentonite and sodium fluorohectorite on the rheological behavior of natural rubber, carboxylated styrene butadiene rubber latices, and their blends was analyzed with special reference to shear rate, temperature, and filler loading. The layered silicates‐reinforced latex samples were characterized by X‐ray diffraction technique to analyze the extent of intercalation and exfoliation. In the presence of layered silicates, latex systems exhibited enhancement in viscosity due to the network formation. Because of the breaking of networks at higher temperature, the viscosity of all systems decreased with increase in temperature. Layered silicates‐reinforced latex systems showed pseudoplastic flow behavior and possesses enhanced zero shear viscosity and yield stress. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2355–2362, 2006     

Dietary CLA alters yolk and tissue FA composition and hepatic histopathology of laying hens

The effect of dietary CLA along with n-3 PUFA on yolk FA profile and hepatic lipid accumulation was investigated. Laying hens (n=40) were randomly assigned to four experimental diets containing 0, 0.5, 1.0, or 2.0% CLA. Menhaden oil was used as the source of n-3 PUFA. Dietary CLA did not affect the total lipid content of egg yolk (P>0.05). The amounts of CLA isomers (cis-9 trans-11, trans-10 cis-12) in the egg yolk were proportional to the levels of CLA in the diet (P<0.05). The total CLA content in the egg yolk was 0, 0.97, 2.4, and 5.3 wt%, respectively (P<0.05). Addition of CLA resulted in an increase in saturated FA (P<0.05) with a concomitant reduction in monounsaturated FA (P<0.05) in the yolk, liver, abdominal fat, breast, and thigh muscle. No difference in saturated and monounsaturated FA content in heart and spleen tissue was noted. Dietary CLA at all concentrations resulted in an increase (P<0.05) in the total number of fat vacuoles and lipid infiltration in hepatocytes. The number of cells with 75% or higher lipid vacuolation in the cytoplasm was also increased (P<0.05) by 2.0% CLA. Dietary CLA at 0.5% levels resulted in an increase (P<0.05) in the total lipid content of hepatic tissue. The total lipid content in leg muscle was lower (P<0.05) in CLA-fed birds. However, no effect of CLA on lipid content of breast muscle, heart, spleen and adipose tissue was observed (P>0.05). The current study used CLA in a FFA form. The effects of using CLA in other form such as TG on avian hepatic tissue need to be investigated.     

Integration of the IMS/PCC framework into the mobile WiMAX network

This article highlights WiMAX network requirements and functionality for integration with 3GPP Rel 7 IMS/PCC architectures.     

Scanning AES and XPS analysis of a thin Au emissivity barrier on Ni alloy

Scanning Auger electron spectroscopy and x-ray photoelectron spectroscopy were used to analyze discolored gold plating on nickel alloys. Gold plated nickel alloy sheets have been used as a thermal shield inside nacelle housings for various jet engines. The thin gold film is applied to serve as a low emissivity coating to reflect thermal radiation. Inconel 625 sheet was gold plated and exposed to 590°C in air for 924 hours to achieve an appropriate service use reference point. The visual appearance of the gold thin-film surface had noticeably dulled after this prolonged exposure. In some cases, several dark spots a few microns in size also appeared on the dulled gold surface. Our hypothesis was that nickel or some alloy constituent had diffused through the gold film and changed the color of the gold surface. X-ray photoelectron spectroscopy and Auger electron spectroscopy were used to differentiate the composition of the gold plated Inconel samples prior to thermal exposure and after the prolonged exposure. Scanning Auger micrographs showed that the composition of the dulled gold surface had changed due to the diffusion of nickel from the substrate alloy through the gold thin film. Nickel was absent at the surface of the unexposed samples while significant nickel concentrations were detected on the discolored gold surface and with the highest nickel levels detected in the dark spots on the gold surfaces. Auger depth profiles made on the exposed gold film verified that a discrete gold layer remained on top of the Inconel with a broad Ni-Cr-Au zone beneath this gold layer.     

Mercury-metallothionein and the renal accumulation and handling of mercury

In the present study, we evaluated the renal and hepatic accumulation of mercury, the intrarenal distribution of mercury and the urinary and fecal excretion of mercury in rats injected intravenously with a non-toxic 0.1 mumol/kg-dose of mercury in the form of mercuric chloride (HgCl2) or a complex of mercury-metallothionein (Hg-MT). Between 6 and 72 h after injection, the concentration of mercury in the kidneys of the rats injected with Hg-MT was significantly greater than that in the rats injected with HgCl2. The greatest difference in the renal concentration of mercury between the two groups of rats was detected 6 h after injection. In the kidneys of both experimental groups of rats, the cortex and the outer stripe of the outer medulla contained the highest concentrations of mercury, with the greatest concentrations found in the renal cortex and outer stripe of the outer medulla of the rats injected with Hg-MT. No differences were found between the two experimental groups with respect to the concentration of mercury in the renal inner stripe of the outer medulla and inner medulla throughout 72 h of study. The content of mercury in the blood and liver decreased over time in both groups of rats, but was always significantly greater in the blood and liver of rats injected with HgCl2. The rats injected with Hg-MT excreted more than eight times the amount of mercury in the urine than the corresponding rats injected with HgCl2 during 72 h. These data indicate that there may be decreased tubular reabsorption of filtered Hg-MT and/or tubular secretion of mercury in the rats injected with Hg-MT. In contrast, the rats injected with HgCl2 excreted significantly more mercury in the feces during the same period of time than the corresponding rats injected with Hg-MT. In conclusion, our data clearly indicate that the renal and hepatic uptake and accumulation of mercury, and the urinary and fecal excretion of mercury, are altered significantly when inorganic mercury is administered intravenously as a complex with metallothionein.     

Characteristics of turbulent nonpremixed jet flames under normal- and low-gravity conditions

An experimental study was performed with the aim of investigating the structure of transitional and turbulent nonpremixed jet flames under different gravity conditions. Experiments were conducted under three gravity levels, viz., 1 g, 20 mg, and 100 μg. The milligravity and microgravity conditions were achieved by dropping a jet-flame rig in the University of Texas at Austin 1.25-s and NASA-Glenn Research Center 2.2-s drop towers, respectively. The flames studied were piloted nonpremixed propane, ethylene, and methane jet flames at source Reynolds numbers ranging from 2000 to 10,500. The principal diagnostic employed was time-resolved cinematographic imaging of the visible soot luminosity. Mean and root-mean-square (RMS) images were computed, and volume rendering of the image sequences was used to investigate the large-scale structure evolution and flame tip dynamics. The relative importance of buoyancy was quantified with the parameter, ξL, as defined by Becker and Yamazaki (Combust. Flame 33 (1978) 123-149). The results showed, in contrast to some previous microgravity studies, that the high-Reynolds-number flames have the same flame length irrespective of the gravity level. The mean and RMS luminosity images and the volume renderings indicate that the large-scale structure and flame tip dynamics are essentially identical to those of purely momentum-driven flames provided ξL is less than approximately 2-3. The volume renderings show that the luminous structure velocities (i.e., celerities) normalized by the jet exit velocity are approximately constant for ξL<6, but scale as for ξL>8. The flame length fluctuation measurements and volume renderings also indicate that the luminous structures are more organized in low gravity than in normal gravity. Finally, taken as a whole, this study shows that ξL is a sufficient parameter for quantifying the effects of buoyancy on the fluctuating and mean characteristics of turbulent jet flames.