Software reuse issues and perspectives

Software reuse could be implemented at several levels including the specification level, design level, program/subprogram library level, code level, and object-code level. However, reuse has a distinct definition for each of the above-mentioned levels. Moreover, the techniques applied to organize and manage reuse is different from one level to another. What's more, the complexity of the reuse methods and techniques increases as it moves from the specification level to the code and object-code levels. On the positive side, the time and space efficiency resulting from the application of reuse techniques improves in the same direction. Specification and design levels are at higher levels of abstraction than the other reuse levels, therefore their potential for accommodating reuse is greater and their adaptation to new applications can be simpler. However, the reuse process of the specification and design levels ultimately involves coding (be it system-generated or manual), testing, and debugging. On the other hand, reuse at code and object-code levels essentially eliminates coding and overall testing, hence it is more economical where a large collection of reusable software is organized in a software library     

On the detection of motion and the computation of optical flow

A method for the detection of motion in image sequences is presented. In this method, the intensity history at each pixel is convolved with the second derivative in time of a temporal Gaussian smoothing function. The zero crossings in a single frame of the resulting function indicate the positions of moving edges. Intensity changes in time due to illumination effects do not produce zero crossings; thus, they are not interpreted as motion by the present method. It is also shown that the spatial and temporal derivatives of this function can be used to compute the component of the optical flow that is normal to the zero-crossing contours. This computation is also insensitive to nonconvective temporal and spatial variations in the image intensity that are caused by illumination effects     

Assessment of improvement of myocardial fatty acid uptake and function after revascularization using iodine-123-BMIPP

We investigated the effect of bioflavonoid quercetin on tyrosine phosphorylation and phospholipase D (PLD, EC 3.1.4.4) activation in rabbit peritoneal neutrophils stimulated by N-formylmethionyl-leucyl-phenylalanine (fMLP). The quercetin dose-dependently inhibited degranulation and superoxide production in fMLP-stimulated neutrophils. A strong inhibitory effect of quercetin on the tyrosine phosphorylation of several proteins (40, 42, 43, 45, 46 and 75 kDa) was observed when the neutrophils were pretreated with different concentrations of quercetin. Furthermore, quercetin inhibited mitogen activated protein kinase (MAP kinase) and PLD activation induced by fMLP in a dose-dependent manner. The reduction in PLD activity was 30% at 0.1 microM and 70% at 100 microM of quercetin. These results suggest that impairment of neutrophil functions by quercetin may be due, at least in part, to inhibition of tyrosine phosphorylation and PLD activation.     

Cloning of a novel retinoic acid-inducible mRNA from human osteoblast-like cells

Retinoids have long been known to influence skeletal development and bone remodeling. Cells of the osteoblastic lineage play a key role in these processes. In this study we have used the differential display PCR technique to identify retinoic acid (RA)-induced mRNAs in human osteoblast-like cells. We report the cloning and sequencing of one such mRNA, AT-RA 6, which was specifically induced by all-trans RA both in normal human osteoblast-like cells and in MG-63 osteosarcoma cells. Maximal expression was found after 60 min, suggesting that this may be an early response gene. Expression was found in all tissues examined. No homology to known mRNA sequences was detected.     

Investigation of driving performance, vection, postural sway, and simulator sickness in a fixed-based driving simulator

This paper reports the results of a pilot study conducted to determine whether there is a relationship between simulator sickness and measures of driver inputs, vection, and postural sway, in a fixed base driving simulator. Seven males and four females performed a series of alternating left and right turns (20 each), with straigth-aways inbetween. The task was designed to promote experiences of circular and linear vection, and associated sway. It was hypothesized that greater driver inputs (i.e., steering wheel and braking activity; deviation from the centerline) would correlate: with reports of vection and measures of postural sway. Ten of the eleven subjects reported moderate sickness, which precluded any statistical comparisons between “sick” and “not sick” however, there was a significant tendency for persons who reported vection to also report sickness. There were no gender differences in reported incidence of vection or sickness, however, males tended to exhibit greater lateral velocity. The next phase of investigation will necessitate reducing the strength of the stimulus (i.e., require less turns) to increase variability of sickness scores amongst subjects and permit comparisons between “sick” and “not sick.” Measurement considerations include increasing the sensitivity of vection ratings, and examination of the timecourse for the development of postural sway.     

Separation of paraproteins from human plasma by membrane chromatography

The purpose of this study was to assess the effects of acute pharmacological interventions on the ischemia-reperfusion damage in a canine model of hypothermic global myocardial ischemia. Three experimental groups each consisting of seven animals were subjected to 2 h of global ischemia followed by 1 h of reperfusion. Group A (control) used Tyers' iso-osmolar potassium cardioplegia solution; group B received allopurinol (40 mg/kg), 95% intravenously (IV) systemically with 5% added to the final infusion of Tyers' solution. In group C, superoxide dismutase (6.5 mg/kg) was used, one third of the total dose in the final delivery of the Tyers' cardioplegia solution and two thirds IV during the initial 5 min of reperfusion. In all three groups, myocardial temperature was maintained between 15 and 19 degrees C. Methods of evaluation included hemodynamic and echocardiographic parameters of ventricular function. Assessment was performed at three time periods: pre-cardiopulmonary bypass (control), 60 min postreperfusion and immediately post-volume loading (at 2 h after cardiopulmonary bypass). No significant deterioration of myocardial function was observed in either of the experimental groups after the use of these preservation techniques. Comparison of regression slopes based on analysis of covariance for myocardial performance, systolic function, and diastolic compliance did not demonstrate any significant differences between the groups. Two hours of global ischemia was not sufficient to cause measurable damage to the myocardium on the basis of which the pharmacological intervention with allopurinol and superoxide dismutase could be evaluated. The controversy surrounding the use of allopurinol and superoxide dismutase is discussed with the findings of this experimental protocol and is brought up for scientific dialogue.