A Comparison of Inspector Performance Measures

Using experimental data from their signal-detection study, the authors examine traditional measures of inspector performance along with measures based on Bayes'rule. Results indicate that the inspector's decision process is affected by the a priori probability of nonconforming product in the inspection lot and that inspector decision error may result in a tighter OC curve for a sampling plan. The conclusions are that performance measures should be selected relative to performance evaluation objectives and that graphs describing acceptance sampling plans for ideal inspectors should be modified to reflect performance of real inspectors under actual conditions.     

Basics of cutaneous wound repair

BACKGROUND: Cutaneous wound repair consists of multiple integrated networks of cell-matrix-cytokine interactions. It is generally believed that a better understanding of these networks will lead to improved care of cutaneous wounds, whether freshly made by the surgeon's scalpel or previously existing and not healing secondary to underlying abnormalities. OBJECTIVE: This review is intended to update the readership in some of the salient aspects of wound repair networks. METHODS: To facilitate the review of multiple integrated networks, cutaneous wound repair was arbitrarily divided into three phases: inflammation, tissue regeneration including re-epithelialization and granulation tissue formation, and tissue reorganization. RESULTS: Throughout the entire process of wound repair it is clear that cells produce or alter various cytokines and extracellular matrix. The cytokines and matrix in turn alter the behavior of the producer cells (autocrine response) or neighbor cells (paracrine response). CONCLUSION: The dynamic reciprocity among cells, cytokines, and matrix material helps explain how integrated wound healing networks are sequential as well as tightly controlled.     

Effects of hydrogen peroxide on lipoproteins and associated lipids

Lipoproteins isolated from human or chimpanzee serum were treated with H₂O₂ and allowed to stand varying lengths of time before quantitative analysis in the ultracentrifuge. Marked instability of ultracentrifugal boundaries (convection) occurred during the first 24 hr, but diminished thereafter. Simultaneously, the quantity of lipoprotein decreased. The instability of boundaries in H₂O₂-treated samples was presumed to reflect loss of lipid-protein affinity and breakdown of lipoproteins under the force of ultracentrifugation. Analysis of extracted lipids showed that H₂O₂ caused little loss of phospholipid, significant loss of triglyceride, and apparent loss of cholesteryl ester. The latter loss, however, was accompanied by appearance of esterified cholesterol in the free cholesterol eluent. Apparently H₂O₂ converted some cholesteryl esters to a more polar form which was eluted later from the column, with the free cholesterol fraction. Gas chromatographic analysis of the fractions eluted from the column showed that selective degradation of polyunsaturated fatty acids was most marked with cholesteryl esters, somewhat less with triglycerides, and negligible with phospholipids. It was postulated that the loss of lipid-protein affinity caused by H₂O₂ in vitro may reflect a similar process in vivo, i.e., that one process contributing to development of atherosclerosis can be oxidation of lipoprotein, with loss of lipid-protein affinity and accumulation of lipid products in (or on) cells of the vascular system. Presented at the AOCS Meeting, Washington, D. C., April, 1968.     

Effect of methionine hydroxy analog supplementation on dairy cattle hoof growth and composition

Fifty lactating Holstein cows were assigned randomly to one of two treatments, control and control plus approximately 30 g methionine hydroxy analog, and confined on concrete for 11 mo. The control diet consisted of sorghum silage and concentrate fed as a blended ration. Sulfur contents of dry matter were .12% and .16% for control and methionine hydroxy analog rations. Hoof growth and hardness were measured on front and rear right abaxial claws in the dorsal and lateral regions. Hoof growth rates were measured for four periods; summer-fall, fall-winter, winter-spring, and spring-summer, each 70 to 90 days. Hooves of cows fed methionine hydroxy analog grew faster than those of control cows during spring-summer in all regions. Variations of growth rates of hooves were seasonal and tended to follow variations in daily photoperiod. Wear rates were not affected significantly by treatment. Hooves of cows fed methionine hydroxy analog were softer in the top dorsal region at the end of winter-spring and in the dorsal toe region at the end of spring-summer. All other locations were not affected significantly by treatment. The toe region was harder than the top of the hoof. Cows fed methionine hydroxy analog had less cysteine and proline in hoof than control cows and greater percentages of methionine lysine, tyrosine, and glutamic acid. These results suggest that a decrease of disulfide bonding occurred in the hoof tissue of cows fed methionine hydroxy analog. Cows fed methionine hydroxy analog produced more actual milk, milk fat, and 4% fat-corrected milk during 180 days than did control cows.     

NEURAL NETWORK PATTERN RECOGNITION OF BLAST FRAGMENT SIZE DISTRIBUTIONS

Neural networks have considerable potential for applications in particulate image analysis. An area of great current interest is to use image analysis techniques to characterize particle size distributions in video images of blasted rock. A simulated neural network was trained to recognize fragmented rock size classes taken from images of blasted ore in a large open pit mining operation. Size distributions were assigned to categories such as 40% and 60% minus six inches. Pattern recognition features were extracted from digitized images using two-dimensional Fourier transforms. These features were then used as a training set to enable the neural network to recognize the size category of subsequent images of blasted rock taken from the mining operation. Training sets were developed for a back propagation algorithm by hand sorting and sizing the blast fragments from photographed piles. Within the limits of this experiment, the trained network consistently recognized the size distribution categories. A trained neural network can be readily calibrated to adjust for changes in light and shadow, a problem which plagues algorithm-based blast fragmentation analysis routines. Neural network techniques may provide a solution to the problem of rapid and reliable on-line and on-site size distribution recognition and assessment.     

Effects of in vivo hypoxia on acetylcholine synthesis by rat brain synaptosomes

Synaptosomes from normoxic and hypoxic rats were incubated aerobically in the presence and absence of veratridine. In the absence of veratridine, no significant difference was observed between the two types of preparation regarding either ATP/ADP ratio or 14CO2 or [14C]acetylcholine synthesis from D-[U-14C]glucose. However, in the presence of veratridine, significant reductions in the output of 14CO2 and [14C]acetylcholine by synaptosomes from hypoxic rats were apparent. It was concluded that irreversible metabolic lesions occur at the synapse as a result of hypoxia, which are apparent only when the metabolism of the preparation is accelerated to a level comparable with the maximal rate occurring in vivo. The presence of such lesions is further evidenced by the significant reductions in ATP/ADP ratio, 14CO2 output, and [14C]acetylcholine synthesis that occur in synaptosomes from hypoxic rats made anoxic in vitro and permitted to recover. Such decreases are not seen when synaptosomes from normoxic rats are similarly treated.     

In vivo kinematics of the cervical spine. Part I: Development of a roentgen stereophotogrammetric technique using metallic markers and assessment of its accuracy

A technique for simultaneous roentgen stereophotogrammetry (RS) was developed, and its accuracy was assessed. In vitro models fabricated from dried cadaveric C4 and C5 vertebrae were used to simulate the motion behavior of the cervical spine. Metallic markers made of Vitallium beads (diameter < 0.3 mm) were implanted into the posterior and anterior surfaces of each vertebra at surgically accessible locations to simulate the bead placement for both posterior and anterior surgical approaches to the cervical spine. A series of roentgen stereo pairs were obtained to systematically assess the accuracy (validity) of displacement measurements in anteroposterior (AP) translation, axial rotation, and flexion/extension. In addition, the effects of soft tissue density on the accuracy of the system were investigated by obtaining a series of roentgen stereo pairs with the experimental model immersed in a water bath. The coordinates of the metallic markers on the radiographs were then digitized by two raters who were not informed of the actual motion (i.e., blind study). The results indicated a high accuracy throughout the study. Overall root mean square errors were 0.07 mm for AP translation, 0.08 degrees for axial rotation, and 0.14 degrees for flexion/extension. The corresponding accuracy estimates (R2 values by linear regression analysis) were very high (0.992, 0.998, and 0.995) when the measurement results were compared with the actual displacements. The water bath did not affect measurement accuracy, indicating that soft tissue density should have little effect on the accuracy of the technique for in vivo applications. This system appears to be an accurate and reliable method for assessment of simulated in vivo cervical spine motion, regardless of the rater. The technique has been further used in in vivo assessment of cervical spine kinematics in one patient to confirm the efficacy of the developed technique.     

Anomalous vapour pressure over liquid D-T

The presence of a few tenths mol % helium in hydrogen causes anomalous vapour pressures as high as 10 kPa. This effect is caused by the combination of a small cold cell, a single, long fill tube, and the insolubility of helium in liquid hydrogen. This effect is important in the handling of deuterium-tritium, as radioactive decay produces He³.     

Pyridoxal 5'-phosphate and the regulation of ornithine decarboxylase activity and stability

There are two forms of ornithine decarboxylase with respect to pyridoxal 5'-phosphate (pyridoxal-P) affinity in exponentially-growing Swiss 3T3 mouse fibroblasts: form I (Km approximately 10 muM) accounts for 30% of the total activity, and form II (Km approximately 0.4 muM) the remainder. Each form of the enzyme is in rapid equilibrium with ornithine and pyridoxal-P; neither form recognizes the Schiff base between ornithine and pyridoxal-P as a substrate. Total pyridoxal-P concentrations indicate that both forms may normally be at least partially active in vivo. Upon stimulation of 3T3 cells by pituitary growth factors, form I becomes undetectable within 4 h. As total activity increases over 10-fold during this time and continues to increase thereafter, a possible conversion of form I to form II could account for this increase only if the Km change reflects other changes in preexisting enzyme. The rates of cofactor dissociation are apparently the same for each form and neither rate changes with the growth state. Since rapid equilibrium kinetics apply, the forms apparently differ in their rate of cofactor association. The half-lives of the two forms in vivo are the same in unstimulated cells when measured concurrently. Also, the half-life of total activity decreases markedly upon stimulation as form II becomes dominant. These and other observations are not consistent with pyridoxal-P serving a major protective function for the enzyme in vivo.     

Getting blood from collective turnips: Volunteer donation in mass blood drives.

Analyzed correlates of volunteer blood donation in 2 separate mass blood drives, based on data from 1,722 university students, 1,080 donors and 642 nondonors. Previous research on blood donor motivation has suggested that altruistic, humanitarian reasons are the chief motives for donation. Present results indicate virtually no association between donorship and altruism (measured by a modified version of Wrightman's Philosophies of Human Nature Scale). Donors were more responsive to social pressure and incentives and less impeded by a free-rider tendency and the costs of giving than were nondonors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)