Measurement of water vapor in the stratosphere by photodissociation with Ly alpha (1216 A) light

Photodissociation of polyatomic molecules by vacuum-uv light often results in the formation of electronically excited diatomic molecular fragments. Based on this, instruments that measure mixing ratios or densities of selected polyatomic species in the stratosphere and higher troposphere can be constructed. This is demonstrated by an instrument to detect and measure stratospheric water mixing ratios utilizing H(2)O photodissociation by Ly alpha (1216 A) light and detecting OH(A(2)J(+)X(2)Pi) emission. Also, detectors for H(2)O(2), HNO(3), and NO(2) are discussed.     

Open compared with laparoscopic approach to Burch colposuspension: a cost analysis

OBJECTIVE: To compare postoperative course and hospital charges of an open versus laparoscopic approach to Burch colposuspension for the treatment of genuine stress urinary incontinence. METHODS: A retrospective chart review was performed to identify all patients undergoing open or laparoscopic Burch colposuspension by the same surgeon over a 2-year period. Patients undergoing additional surgical procedures at the time of colposuspension were excluded from the study. Twenty-one patients underwent open Burch colposuspension and 17 patients underwent laparoscopic colposuspension. Demographic data including age, parity, height, and weight were collected for each group. Both groups also were compared with regard to operative time, operating room charges, estimated blood loss, intraoperative complications, change in postoperative hematocrit, time required to resume normal voiding, length of hospital stay, and total hospital charges. RESULTS: The laparoscopic colposuspension group had significantly longer operative times (110 versus 66 minutes, P < .01) and increased operating room charges ($3479 versus $2138, P < .001). There was no statistical difference in estimated blood loss or change in postoperative hematocrit between the two groups. No major intraoperative complications occurred in either group. Mean length of hospital stay was 1.3 days for the laparoscopic group and 2.1 days for the open group (P < .005). However, total hospital charges for the laparoscopic group were significantly higher ($4960 versus $4079, P < .01). CONCLUSION: Laparoscopic colposuspension has been described as a minimally invasive, cost-effective technique for the surgical correction of stress urinary incontinence. Although the laparoscopic approach was found to be associated with a reduction in length of hospital stay, it had significantly higher total hospital charges than the traditional open approach because of expenses associated with increased operative time and use of laparoscopic equipment.     

Influence of human model resolution on computed currents induced in organs by 60-Hz magnetic fields

The effects of human body model resolution on computed electric fields induced by 60 Hz uniform magnetic fields are investigated. A recently-developed scalar potential finite difference code for low-frequency electromagnetic computations is used to model induction in two anatomically realistic human body models. The first model consists of 204290 cubic voxels with 7.2-mm edges, while the second comprises 1639146 cubic voxels with 3.6-mm edges. Calculations on the lower-resolution model using, for example, the finite difference time domain or impedance methods, push the capabilities of workstations. The scalar method, in contrast, can handle the higher-resolution model using comparable resources. The results are given in terms of average and maximum electric field intensities and current density magnitudes in selected tissues and organs. Although the lower-resolution model provides generally acceptable results, there are important differences that make the added computational burden of the higher-resolution calculations worthwhile. In particular, the higher-resolution modelling generally predicts peak electric fields intensities and current density magnitudes that are slightly higher than those computed using the lower-resolution modelling. The differences can be quite large for small organs such as glands.     

Stimulation of nitric oxide production in macrophages by Babesia bovis

Gamma interferon (IFN-gamma)-activated macrophages are believed to play a key role in resistance to Babesia bovis through parasite suppression by macrophage secretory products. However, relatively little is known about interactions between this intraerythrocytic parasite and the macrophages of its bovine host. In this study, we examined the in vitro effect of intact and fractionated B. bovis merozoites on bovine macrophage nitric oxide (NO) production. In the presence of IFN-gamma, B. bovis merozoites stimulated NO production, as indicated by the presence of increased L-arginine-dependent nitrite (NO2-) levels in culture supernatants of macrophages isolated from several cattle. The merozoite crude membrane (CM) fraction stimulated greater production of NO, in a dose-dependent manner, than did the merozoite homogenate or the soluble, cytosolic high-speed supernatant fraction. Stimulation of NO production by CM was enhanced by as little as 1 U of IFN-gamma per ml of culture medium. Upregulation of inducible NO synthase mRNA in bovine macrophages by either B. bovis-parasitized erythrocytes and IFN-gamma or CM was also observed. B. bovis-specific T-helper lymphocyte culture supernatants, all of which contained IFN-gamma, were also found to induce L-arginine-dependent NO2- production. Supernatants that induced the highest levels of NO also contained biologically active TNF. These results show that B. bovis merozoites and antigen-stimulated B. bovis-immune T cells can induce the production of NO, a molecule implicated in both protection and pathologic changes associated with hemoprotozoan parasite infections.     

The use of vibration measurements for quality control of machine tool spindles

The assembly of machine tool spindles results in a degree of variability in the effective stiffness of the bearings. This may result in a poor machining performance if the bearing stiffnesses are below their specified design values. Alternatively, the life of the bearings may be reduced if the bearings stiffnesses are above the design values because of excessive preload. This paper describes a method of checking the spindle assembly by making vibration measurements. From these measurements it is possible to determine which bearings (if any) are not at their design stiffness. This then allows appropriate adjustments to be made to ensure the assembled spindle is close to the design specifications.     

Repair phenotype in corneal fibroblasts is controlled by an interleukin-1 alpha autocrine feedback loop

PURPOSE: To explore the role of autocrine interleukin-1 alpha (IL-1 alpha) as a central regulator of the repair phenotype in corneal fibroblasts. METHODS: Disruption of the actin cytoskeleton with cytochalasin B (CB), which mimics changes in shape that occur in repair tissues, was used to stimulate repair gene expression in early-passage fibroblasts. Changes in expression of IL-1 alpha, IL-8, collagenase, and ENA-78 were determined by Northern blot analysis, radioimmunoassay, and an enzyme-amplified sensitivity immunoassay (EASIA). Expression of repair genes was also examined in repair fibroblasts, isolated from healing, penetrating keratectomy wounds in rabbits. RESULTS: Blocking IL-1 alpha activity prevented both constitutive and stimulated increases in synthesis of IL-8 and collagenase in early-passage cultures of corneal fibroblasts, demonstrating the role of IL-1 alpha as a necessary intermediate for expression of these genes. Evidence is also presented that the IL-1 alpha autocrine controls expression of an IL-8 related factor, ENA-78. Unlike early-passage fibroblasts, fibroblasts freshly isolated from the uninjured cornea did not express IL-1 alpha. However, fibroblasts freshly isolated from remodeling corneal repair tissue 3 weeks after injury were found to express substantial levels of IL-1 alpha, regulated through an autocrine feedback loop. Neutralization experiments demonstrated that the IL-1 alpha autocrine is largely responsible for controlling both collagenase and IL-8 synthesis in repair fibroblasts, as it is in early-passage fibroblasts. CONCLUSIONS: These findings provide evidence that activation of an autocrine IL-1 alpha feedback loop is an important mechanism by which fibroblasts adopt a repair phenotype during remodeling of the cornea.     

Determination of Strength and Index Properties of Fine-Grained Soils Using a Soil Minipenetrometer

This paper describes the use of a soil minipenetrometer (SMP) to determine the strength and index properties of fine-grained soils. The SMP has been developed to allow both fall cone and quasi-static penetration tests to be performed. Displacement controlled quasi-static penetration tests can be used for the direct measurement of undrained shear strength, both for remolded and undisturbed samples. In addition the quasi-static penetration test can be used to define an additional lower plastic limit parameter, the PL100, which represents the moisture content of a fine-grained soil with an undrained strength 100 times that at the liquid limit. This approach offers the advantage that removal of the coarse fraction is not required to estimate the PL100.     

Identification of a complex congenital heart defect susceptibility locus by using DNA pooling and shared segment analysis

The isotope dilution technique of [6-3H]glucose, [U-14C]lactate and [l-14C]propionate was used to evaluate the effect of dietary chromium (Cr) supplementation on whole-body kinetics of glucose, lactate, and propionate in rams. Rams were fed a high grain diet at 2% of body weight with or without 0.5 ppm of supplemental Cr from chelated Cr for the initial 14 days, and then intake was increased to 2.5% at body weight for the last 9 days. Weight gain was enhanced (P < 0.01) with Cr supplementation. Plasma concentrations of glucose, lactate, and propionate were not influenced by Cr supplementation. Turnover rates of glucose and lactate, and their interconversion were also not influenced. Propionate turnover rate tended to increase (P = 0.11) and the conversion of propionate to glucose increased (P < 0.05) with Cr supplementation, leading the increased proportional contribution of propionate to glucose turnover rate (P < 0.05). Chromium supplementation may influence the contribution of each glucogenic substrate for glucose production in rams fed a high grain diet.     

Intracranial aneurysms treated with the Guglielmi detachable coil: midterm clinical results in a consecutive series of 100 patients

The purpose of this study was to investigate in vitro the potential effect of type 1 collagen gel containing alpha-elastin on the proliferation of vascular smooth muscle cells and vascular endothelial cells, and on smooth muscle cell migration. Vascular smooth muscle cell and endothelial cell were cultured in 12-well plates precoated with collagen gels and alpha-elastin. Cell proliferation rates were measured by monitoring [3H]-thymidine incorporation. After 2, 3 or 4 days of culture, the proliferation rate of both smooth muscle cells and endothelial cells was significantly decreased on collagen gel containing 10 mg/ml alpha-elastin compared with collagen gel only as control. Smooth muscle cell proliferation on collagen gel containing alpha-elastin on the 4th day of culture was decreased dose-dependently, e.g. 1 mg/ml of alpha-elastin (74.8(2.3)% of control, P=n.s.); 5 mg/ml (56.7(2.1)%; P<0.05); 10 mg/ml (30.3(3.1)%; P<0.005). In the case of cultured endothelial cells, however, [3H]-thymidine incorporation was not decreased significantly in the presence of 5 mg/ml alpha-elastin (83.1(7.9)%, P=n.s.). After stimulation by platelet-derived growth factor, the smooth muscle cell migration rate on collagen gel containing alpha-elastin (5 mg/ml) was decreased over time. The area of migration on the 6th day of culture was also significantly decreased dose-dependently in the presence of alpha-elastin, e.g. 1 mg/ml (72.6(3.4)% of control, P<0.05), 5 mg/ml (56.9%(1.5)%; P<0.05); 10 mg/ml (37.3(2.7)%; P<0.0005). In conclusion, alpha-elastin inhibited the proliferation and migration of smooth muscle cell in a dose-dependent manner on collagen gel culture, however, at high concentrations of alpha-elastin (10 mg/ml), the endothelial cell proliferation rate was also inhibited. At 5 mg/ml, alpha-elastin significantly inhibited smooth muscle cell proliferation and migration but did not significantly inhibit endothelial cell proliferation. Incorporation of collagen gel containing alpha-elastin into the structure of arterial prosthesis offers the possibility of inhibiting smooth muscle cell hyperplasia without significant effect on endothelial cell formation.