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OBJECTIVE: To compare the subjective image quality of three intra-oral storage phosphor systems. METHODS: DenOptix (Dentsply/Gendex, Chicago, IL, USA), Digora (Soredex, Helsinki, Finland), and CD-Dent (DigiDent Digital Imaging Technologies, Nesher, Israel) were compared. Two different imaging plates (IPs), BAS300 and HR300 (Fuji Photo Film Co., Tokyo, Japan) were used with the DenOptix system. The specimen was the maxilla and surrounding soft tissues of an adult cadaver. Imaging was at 70 kVp and 8 mA with a focus-detector distance of 38 cm using an optical bench. The exposure times were varied and a panel of five dentists independently evaluated the images produced with each system/IP receptor for seven features; proximal caries, gingival soft tissues, cortical bone, root canal space, root apices, periodontal ligament space and endodontic instrument clarity on a three-interval confidence scale. The best three exposures were chosen according to the highest scores for each system. These images were re-read in random order a total of 10 times. Pair-wise comparisons were made by use of odd's ratio analysis. A 95% confidence interval was applied. RESULTS: Images made with the DenOptix system/BAS IP combination were perceived to have the best overall image quality. The DenOptix/HR IP combination and Digora were rated almost equally in second place. The DigiDent system was ranked inferior. The Digora was considered to be the best for demonstrating gingival soft tissues (P < 0.05) and the DenOptix/HR300 combination the best for clarity of endodontic instruments (P < 0.05). CONCLUSIONS: While the DenOptix/BAS 300 combination was rated highest overall, the ranking of image quality by modality was found to be task-dependent. Digora was rated best for demonstrating gingival soft tissues.

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We recently identified a simian parvovirus (SPV) in cynomolgus monkeys with severe anemia. We describe here the clinical and epidemiological findings in the original outbreak and in a second episode of anemia involving monkeys in a drug safety study at a separate facility. The major clinical findings associated with SPV infection were a severe normocytic, normochromic anemia. In the original episode the anemia was predominantly nonregenerative, whereas in the second outbreak there was an initial strong, regenerative response. In the absence of predisposing factors, SPV infection was mild or inapparent. However, the presence of concurrent acute infection with type D simian retrovirus in the original episode is believed to have been a major predisposing factor for the development of immunodeficiency and persistent SPV infection, culminating in severe anemia. It is unclear whether simian retrovirus infection played a role in the second episode, but it is possible that the drug used may have been a factor, because severely anemic monkeys were in the high drug dosage group. We conclude that SPV should be considered in the differential diagnosis of severe anemia in monkeys.

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Cardiovascular changes associated with indwelling catheters were evaluated in 51 adult beagle dogs catheterized for 4 to 9 weeks. Pathologic changes consistent with traumatic injury were in the vena cava and endocardium of the right atrium of 88% of cannulated dogs. Lesions were characterized by surface denudation and diffuse intimal thickening due to myointimal hyperplasia and deposition of extracellular matrix. Affected intima was lined by hyperplastic, poorly differentiated endothelial cells and contained round to oval cells with characteristics of smooth muscle cells. After 9 weeks, thickened intima was vascularized and composed of spindle-shaped cells and fibrillar stroma. Intimal sclerosis and localized proliferative papillary projections in the vena cava cranial to areas of myointimal hyperplasia occurred infrequently. Traumatic lesions, regardless of location or severity, did not extend below the internal elastic membrane. Inflammatory cellular responses, when present, were minimal. The location, distribution, and morphogenesis of catheter-related cardiovascular lesions distinguishes them from those induced by chemical toxicity or pharmacotoxicity.

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An experimental investigation of laser-oscillator frequency locking by a four-wave interaction was conducted. An experiment was performed that successfully demonstrated the locking of two cw dye lasers using this concept with Na vapor serving as the nonlinear (coupling) medium.

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Concentration of iron in plasma, total iron-binding capacity (TIBC), and transferrin saturation are often determined by standard spectrophotometric methods, but iron concentration may be quantified by immunoprecipitation or, electrochemically, by controlled-potential coulometry. Because these iron assays do not all measure the same form(s) of iron, we studied subjects in various states of iron nutriture: normal adults, iron-deficient patients, thalassemia patients with unsaturated transferrin or oversaturated transferrin, and patients with idiopathic hemochromatosis. The spectrophotometric and coulometric methods detected essentially all non-heme iron in plasma; results correlated well but showed a negative bias toward the coulometric method. Results by an immunoprecipitation procedure, which measures only transferrin-bound iron, correlated well with those obtained coulometrically but were slightly higher than the latter. The characteristics of the various methods for iron must be understood by the clinical laboratory if diagnosis of iron disorders is to be accurate.

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The results of a Monte Carlo calculation of the probability distribution of the far-field irradiance produced by a thin turbulent layer placed in front of a finite-aperture transmitter are discussed. These results clearly show that Rice-Nakagami and other well-known distributions such as the lognormal distribution are inapplicable to this problem.

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Three alternative selection methods for extending selection limits or breaking response plateaus were compared over ten generations in a replicated model experiment using two unrelated populations of Drosophila melanogaster that no longer responded to purebred selection for high egg number, a heterotic polygenic trait. The three methods were: (1) reciprocal recurrent selection (RRS) with selection within each of the plateaued populations based solely on crossbred performance, (2) a modification of reciprocal recurrent selection (MRRS) with selection within each population based on both purebred and crossbred performance, and (3) purebred selection within a new synthetic population formed by crossing the two plateaued populations.--Conflicting estimates were obtained for heritability of purebred egg number in each of the plateaued populations. The realized heritability values and estimates from diallel analyses indicated an absence of additive genetic variation for both populations; however, estimates from conventional intraclass correlation methods were positive. The diallel analyses revealed significant amounts of nonadditive gene effects for purebred egg number in each population, while the significant gene effects for crossbred egg numbers were additive. Estimates of the genetic correlation between purebred and crossbred egg number were negative (-0.85 +/- 0.68 and -0.32 +/- 0.25) for the two base populations.--All three alternatives to continued purebred selection gave significant responses, with the average gain per generation from MRRS being significantly superior to the other two methods. Observed purebred and crossbred responses under RRS were in agreement with quantitative genetic theory. Such was not the case for MRRS, which suggested the possibility of major gene segregation.--Evidence supporting a negative genetic correlation between purebred and crossbred performance and the possibility of overdominance is presented and discussed.

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The Coulter Model S provides an accurate measurement of total hemoglobin (Hb) content in peripheral blood even when elevated levels of carboxyhemoglobin (HbCO) are present. Commercial standards and diluents for spectrophotometric determinations of cyanmethemoglobin (HiCN) are variable in quality. All diluents studied produce turbidity in some samples, and this may explain why manual Hb determinations tend to be higher than hemoglobin measurement on the Coulter S. The most reliable diluent was the reagent described by Van Kampen and Zijlstra. Its reliability is enhanced by centrifugation of sample in diluent. The use of a narrow-band-pass spectrophotometer for routine HiCN determinations in a clinical laboratory is not recommended because of its sensitivity to turbidity and HbCO.

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A numerical technique to obtain the wave behavior in tightly coupled multimode fibers with inhomogeneous indices is introduced in this paper. The specific problem of the coupling characteristics of two parallel multimode fibers whose index profile is parabolic is treated in detail. It was found that in spite of the fact that rather complicated coupling behavior is observed when multimodes exist, total guide power still exchanges among the fibers in a periodic manner, and the coupling length still increases monotonically as a function of the separation distance between the fibers. It has also been demonstrated that by simply specifying the index profiles of the coupling structure (provided that the profiles are slowly varying), the coupling characteristics can be generated with our technique.

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An efficient and powerful technique has been developed to treat the problem of wave propagation along arbitrarily shaped single-mode dielectric waveguides with inhomogeneous index variations in the cross-sectional plane. This technique is based on a modified finite-element method. Illustrative examples were given for the following guides: (a) the triangular fiber guide; (b) the elliptical fiber guide; (c) the single material fiber guide; (d) the rectangular fiber guide; guide; (g) the optical stripline guide.

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Isolates of Vibrio parahaemolyticus and V. alginolyticus from human and environmental sources were examined for antibiotic susceptibility by the methods of minimal inhibitory concentration (MIC) in broth and agar diffusion. These strains were found to be almost uniformly susceptible to chloramphenicol and tetracycline within attainable serum levels. The relationships of zone sizes to MICs for these two antimicrobial agents and ampicillin conformed essentially to those obtained by standard methods with gram-negative rods. Most strains were resistant to ampicillin and exhibited beta-lactamase activity, which accounted for this resistance. Nine of 30 V. alginolyticus strains from environmental sources were ampicillin resistant but did not produce measurable amounts of beta-lactamase. Three strains exhibited multiresistance to high concentrations of chloramphenicol, tetracycline, and ampicillin, which suggests the presence of plasmids. Although the great majority of vibrios appeared to be susceptible to gentamicin by agar diffusion, susceptibility could not be measured by MIC because the added NaCl, required for growth by the halophilic vibrios, diminished gentamicin activity.

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The use of multiple transmitter beams is shown to significantly increase the peak focal-plane irradiance that can be achieved in the presence of thermal blooming. Computer simulation studies of the beam propagation problem show over a factor of 2 increase in the irradiance of a single beam and a factor of 9 increase when three coherent beams are focused on the same target spot. Preliminary experimental results with three mutually noncoherent, nonoverlapping beams are in qualitative agreement with the computer simulation.

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The theory of multidither adaptive optical radar phased arrays is briefly reviewed as an introduction to the experimental results obtained with seven-element linear and three-element triangular array systems operating at 0.6328 microm. Atmospheric turbulence compensation and adaptive tracking capabilities are demonstrated.

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In two experiments, "proactive inhibition" was observed in the free recall of a succession of 15-word lists. Recall performancc declined across lists when all lists were drawn from the same taxonomic category (e.g., occupations). But this decline did not appear when the successive lists were drawn from discrete subcategories (such as "professional" and "skilled manual" occupations). The findings clarify the conditions in which proactive inhibition effects in free recall are likely to occur. Specifically, when the set of items on any one list is more homogeneous than the set of items from all lists taken together, "proactive inhibition" will be attenuated.

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The sensitivity of Streptococcus faecalis growth to hydrostatic pressures ranging up to 550 atm was found to depend on the source of adenosine triphosphate for growth. Barotolerance of cultures growing in a complex medium with ribose as major catabolite appeared to be determined primarily by the pressure sensitivity of ribose-degrading enzymes. Apparent activation volumes for growth were nearly identical to those for lactate production from ribose, and yield coefficients per mole of ribose degraded were relatively independent of pressure. In contrast, cultures with glucose as main catabolite were less sensitive to pressure; glycolysis was less severely restricted under high pressure than was growth, and yield coefficients declined with pressure, especially above 400 atm. Thus, two distinct types of barotolerance could be defined-one dominated by catabolic reactions and one dominated by noncatabolic reactions. The results of experiments with a series of other catabolites further supported the view that catabolic reactions can determine streptococcal barotolerance. We also found that growing, glucose-degrading cultures increased in volume under pressure in the same manner that they do at 1 atm. Thus, it appeared that the bacterium has no alternative means of carrying out glycolysis under pressure without dilatation. Also, the observation that cultures grown under pressure did not contain abnormally large or morphologically deformed cells suggested that pressure did not inhibit cell division more than cell growth.

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