Inducible and endothelial nitric oxide synthase expression during development of transplant arteriosclerosis in rat aortic grafts

In the vascular system, distinct isoforms of nitric oxide synthase (NOS) generate nitric oxide (NO), which acts as a biological messenger. Its role in the development of transplant arteriosclerosis (TA) is still unclear. To investigate whether NO is involved in TA, we studied the expression of NOS isoforms, inducible NOS (iNOS) and endothelial NOS (eNOS), by immunohistochemistry and in situ hybridization during the first two post-transplantation months and their relation with cold ischemia (1 to 24 hours) and reperfusion injury using an aortic transplantation model in the rat. We found an increased iNOS expression in the intima and adventitia and a decreased expression in the media, whereas eNOS expression was not significantly altered during the development of TA. Co-localization studies suggested that iNOS-positive cells were vascular smooth muscle cells, monocyte-derived macrophages, and endothelial cells. Prolonged ischemic storage time resulted in an increase in eNOS expression in the neointima. In situ hybridization showed iNOS mRNA expression by vascular cells in the neointima and media. NO produced by iNOS and eNOS may be involved, at least in part, in the pathogenesis of TA in aortic grafts. Additional studies are needed to confirm the modulatory mechanism of NO during the development of TA.     

High-performance 10 GHz all-active monolithic modelocked semiconductor lasers

Using a novel design strategy for the epitaxial structure for monolithic modelocked semiconductor lasers, lasers capable of producing <2 ps pulses at 10 GHz with very low high-frequency jitter have been fabricated in a single growth step.     

Mobile robot navigation using the range-weighted Hough transform

Accurate navigation of a mobile robot in cluttered rooms using a range-measuring laser as a sensor has been achieved. To extract the directions and distances to the walls of the room the range-weighted Hough transform is used. The following experimental results are emphasized: The robot extracts the walls of the surrounding room from the range measurements. The distances between parallel walls are estimated with a standard deviation smaller than 1 cm. It is possible to navigate the robot along any preselected trajectory in the room. One special case is navigation through an open door detected by the laser. The accuracy of the passage is 1 cm at a speed of 0.5 m/s. The trajectory is perpendicular to the wall within 0.5 degrees in angle. When navigating through corridors, the accuracy is better than 1 cm at 0.8 m/s-the maximum speed of the robot. Odometric data and laser measurements are combined using the extended Kalman filter. The size of the cluttered rectangular room and the position and orientation (pose) of the robot are estimated during motion. The extraction and the resulting navigation are very robust against both spurious measurements in the laser measurements and disturbing objects     

Ethanol exposure increases expression of c-jun and junD in human neuroblastoma cells

The aim of this study was to investigate the effect of ethanol exposure on the expression of fos and jun genes. Exposure of human neuroblastoma SH-SY5Y cells to ethanol for 2-4 days caused a dose-dependent increase in c-jun and junD mRNA levels, whereas mRNAs for c-fos, fosB and junB were not detectable in control or ethanol-treated cells. Four days of ethanol exposure also enhanced the AP-1 binding activity. Experiments with actinomycin D demonstrated that ethanol did not influence the degradation of c-jun and junD mRNAs. These results demonstrate that long-term exposure to ethanol increases c-jun and junD expression. This effect may be one of the mechanisms through which ethanol influences the gene regulatory system in neuronal cells.     

Allergic sensitization is associated with increased bronchial responsiveness: a prospective study of allergy to laboratory animals

The purpose of this prospective study was to investigate the extent of change in bronchial responsiveness and the prognostic value of methacholine provocation in early sensitization to laboratory animals. Thirty eight laboratory technicians were studied during training (before first exposure) and after having been exposed to laboratory animals for a median 18 (range 5-33) months. On both occasions they were subjected to spirometry, bronchial methacholine challenge, skin-prick tests and blood sampling, and responded to questionnaires. Nine (24%) developed laboratory animal allergy (LAA), defined as animal work-related symptoms (n = 8), or specific immunoglobulin E (IgE) (n = 7) or both. In the LAA group, bronchial responsiveness was normal before employment, but had increased significantly at follow-up compared to technicians who had not developed LAA. Six of the nine LAA subjects had a more than threefold increase in bronchial responsiveness, and three of these reported chest symptoms. Spirometric values were not different between the groups prior to exposure or at follow-up, and had no prognostic value. However, a pre-employment level of total IgE > 100 kU.L-1 predicted the development of LAA (relative risk 2.8). Thus, early LAA was associated with increased bronchial responsiveness in most subjects. In contrast to total IgE, the level of pre-employment bronchial responsiveness or lung function did not influence the magnitude of change in responsiveness, nor predict sensitization.     

Improved spectral properties of an optically pumped semiconductor disk laser using a thin diamond heat spreader as an intracavity filter

This letter describes an optically pumped high-power InP-based semiconductor disk laser with a thin (50 /spl mu/m) diamond heat spreader bonded to the surface of the gain chip. The diamond heat spreader performs the multiple functions of heat removal, spectral filtering, and wavelength stabilization by utilizing the high thermal conductivity and the low thermooptic coefficient of diamond, along with the large free-spectral range of a thin intracavity etalon. A pump-power-limited output power of 680 mW at 1.55 /spl mu/m is demonstrated at a heat sink temperature of -30/spl deg/C, and 140 mW at room temperature. The spectral width was measured to be less than 0.08 nm and the spectral drift with temperature and pump power as low as 0.03 nm//spl deg/C and 0.14 nm/W, respectively.     

A low-power 128-tap digital adaptive equalizer for broadband modems

This paper describes a modem receiver chip containing two 64-tap adaptive finite impulse response (FIR) filters configured in parallel as in-phase and quadrature-phase filters. Each filter has a span of 16 symbols and can be configured for T/2, T/3, or T/4 fractional spacing. A zero-latency pipeline technique is used that allows adaptive filters of arbitrary length without degrading the speed. Power is saved at the algorithmic, architectural, and circuit levels. The chip has support for dynamically tuning coefficient precision, updating rates and filter lengths to reduce power consumption. The chip was fabricated in 0.5-μm CMOS technology and consumes 535 mW of power when operating at 50 MHz with 128 taps, T/4 spacing, and symbol-rate power-of-two LMS updating. This can be further reduced to 280 mW using dynamic power reduction techniques. The power in the FIR filter is 162 mW with maximum precision converged coefficients which corresponds to 5.1 mW per multiply-accumulate operation     

Overnight urinary growth hormone in normally growing prepubertal children: effect of urine volume. The one-year growth study

Wear of the polyethylene tibial components is a potential cause of failure in total knee arthroplasty. In addition to pitting, burnishing, and scratching, subtle striations on the bearing portion of the tibial surface have been observed in components retrieved relatively early after implantation. The striated pattern most typically occurred in areas centrally located within the articulating surface. The striations were anteroposterior directed and were identified as local cold flow at the surface. There was a strong correlation between the medial and lateral striated areas, suggesting that these patterns are related to cyclic rolling of the knee. The general characteristics and alignment of the striations could be attributed to the compressive and tractive forces occurring during femoral rollback. For the clinician, these results suggest that kinematics, as well as contact stress, should be considered when evaluating wear of polyethylene components.