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PubMed1976

A mathematical analysis of the substrate effect observed in 3beta-hydroxysteroid dehydrogenase reactions of rat testicular microsomes.

The substrate effect in enzyme reactions has been explained mostly in terms of an additional substrate binding site on the enzyme other than the catalytic site. A rate equation for the reaction is introduced according to the steady state mechanism as follows: v = (Ps3+Qs2+Rs)/(s3+Ls2+Ms+N), were the six parameters, L,M,N,P,Q, and R, can be determined by the least-squares method from the experimental points. The v vs. s curve has an asymptote parallel to the s abscissa, and can be classified into one of four types. The type A curve has an intersection with the asymptote and an apparent maximum velocity; the curve descends toward the asymptote. Type B has no intersection and no stationary point; the curve ascends toward the asymptote. Type C has two intersections and two stationary points, an apparent maximum velocity and a minimum velocity; the curve ascends toward the asymptote. Type D has no intersection and two stationary points; the curve ascends toward the asymptote. The equation was applied to the 3beta-hydroxysteroid dehydrogenase [EC 1.1.1.145] reaction of rat testicular microsomes. The conversion of 3beta-hydroxyandrost-5-ene-17-one was represented by type C, with an apparent maximum velocity of 0.338 nmole/min/mg protein at 0.912 muM of the substrate concentration, minimum velocity of 0.108 nmole/min at 16.6 muM, and saturating velocity of 0.169 nmole/min at infinite concentration of the substrate. The converson of 3beta-hydroxypregn-5-ene-20-one was of type B, having two inflexion points, 0.320 nmole/min at 2.735 muM and 0.814 nmole/min at 12.39 muM, and a saturating velocity of 3.80 nmoles/min at infinite concentration of the substrate.

Animals↗

PubMed1998

Anatomic study for ideal and safe posterior C1-C2 transarticular screw fixation.

STUDY DESIGN: Directions of the C1-C2 posterior transarticular screw trajectories making the longest path or violating the transverse foramen were measured by using an objective measuring method. OBJECTIVES: To clarify the directions of the screw trajectory marking the longest paths without violating the transverse foramen. To achieve this, diverse directions of the screw trajectories were objectified by measuring the locations of the points of screw intersection on the superior articular surface of C2. SUMMARY OF BACKGROUND DATA: The principal limitation of posterior C1-C2 transarticular screw fixation is the location of the vertebral artery. Because of the lack of an objective measuring method, surgical unsuitability has been decided on the basis of individual experiences as reported in 18% to 23% of cases. METHODS: Sagittal reconstructed computed tomographic images were made at 3.5 mm and 6 mm from the spinal canal. C1-C2 transarticular screw trajectories making the longest path or violating the transverse foramen (dangerous trajectory) were drawn, and their points of screw intersection on the superior articular surface of C2 were measured from the posterior rim of the superior articular surface of C2. When the space available for the screw behind the points of screw intersection by the dangerous trajectory was equal to or less than 3.5 mm, the case was defined as "unacceptable"; when the space available for the screw was more than 3.5 mm but equal to or less than 4.5 mm, it was defined as "risky" for the placement of the screw. RESULTS: Trajectories make the longest paths when they pass an average of 3.6 mm and 2.8 mm anterior to the posterior rim of the posterior articular surface of C2 at 3.5-mm lateral images and 6-mm lateral images, respectively. Four of 64 cases were unacceptable or risky unilaterally on 3.5-mm lateral images, and 21 cases were unacceptable or risky on 6-mm lateral images. A sigmoid-shaped increment curve of the risk was noted as the increasing forward inclination of the screw trajectories increased. CONCLUSIONS: The areas on the superior articular surface of C2 intersected by the trajectories making the longest paths without violating the transverse foramen are clarified as a guide to the ideal and safe trajectories. The theoretical minimal risk and usual risk of the posterior C1-C2 transarticular screw fixation are presented as well.

Adult↗

PubMed2003

Interobserver reproducibility of MIB-1 labeling index in astrocytic tumors using different counting methods.

MIB-1 labeling index has been used as a complementary method to differentiate better and worse prognostic groups of astrocytic tumors. However, its reproducibility has been doubted because of the interlaboratory and interobserver variability. We studied the interobserver reproducibility of four manual counting methods of MIB-1 labeling index, including direct counting, area fraction, line intersection with a graticule, and line intersection without a graticule to estimate the total number of the cells. Using line intersection estimate, either with or without a graticule, yielded a worse result. Those MIB-1 labeling indices of astrocytomas were overlapping with those of anaplastic astrocytomas and glioblastomas. Besides, the intraclass correlation coefficient was smaller, and the coefficient of variation was greater than that attained when using a graticule and counting the total number of cells either directly or by area-fraction estimate. The level of interobserver agreement using an MIB-1 labeling index cutoff value of 11.0 was moderate to substantial when applying the line-intersection estimate, and it was almost perfect when applying the direct counting or the area-fraction estimate. The interobserver reproducibility and agreement of MIB-1 labeling index in astrocytic tumors were different depending on the counting methods. Direct counting with a graticule yielded the best result. Before establishing reference standards for staining and counting, the reproducibility of MIB-1 labeling index should be verified.

Adolescent↗

PubMed2002

A real-time algorithm for the quantification of blood pressure waveforms.

A real-time algorithm for quantification of biological oscillatory signals, such as arterial blood pressure (BP) is proposed which does not require user intervention and works on waveforms complicated by rapid changes in the mean level, frequency, or by the presence of arrhythmia. The algorithm is based on the continous independent assessment of the refractory period (RP). In the first stage, a sample of the signal is band-pass filtered. During the next stage: 1) the local maxima in the filtered signal are identified and their pulse amplitudes (PA) measured on the side opposite to the possible notch position and 2) those maxima whose PA exceeds some threshold are selected and an array of RP values is formed as a fraction of the moving estimate of the interval between successive selected peaks. Finally, the original signal is analyzed by means of two moving averages (MAs) with short and long averaging time intervals. The true peaks are determined as the maxima between intersections of MAs if the peak-to-peak or the intersection-to-intersection intervals since the previous peak and the previous intersection exceed the RP. The algorithm proved to be superior against three commercially available heartbeat detectors yielding an error rate of 0.09%.

Algorithms↗

PubMed1978

Synaptic transmission to the horizontal cells in the retina of the larval tiger salamander.

1. The receptive field diameter for most horizontal cells far exceeds the lateral spread of processes for any cell. Therefore horizontal cells probably receive synaptic input from neighbours as well as from the photoreceptors. The electrical effects of these two synaptic inputs were studied. 2. We have characterized the electrical properties of the horizontal cell inputs by determining the current-voltage curves in dark and light. These curves were compared with those obtained in the presence of Co2+ or Mg2 was nearly identical to the curve in the light. 4. The putative transmitter substances glutamate, aspartate and GABA depolarized the cells by increasing conductance. Current-voltage curves measured in the presence of these substances intersected the dark and light curves at +50 mV, the same level at which the dark and light curves intersect. 5. The light response of cells uith broad receptive fields, between 1.0 and 2.0 mm, showed little or no change in conductance associated with the light response. The input resistance was near 20 Momega, and the current-voltage curves intersected at an extrapolated potential level near 200 mV. 6. In the presence of ACh, electrical properties of the broad field cells reverted to those of the narrow field cells: the receptive field was reduced to 0.5 mm, the imput resistance increased, and the current-voltage curves intersected near +50 mV. Thus ACh appeared to interrupt synaptic input from neighbouring horizontal cells. 7. The results confirm the suggestion that horizontal cells receive a tonic excitatory input from the photoreceptors which is decreased by light. They show that horizontal cells receive an additional input from their neighbours, not associated with a measurable conductance change. The input from neighbours is selectively interrupted by ACh, but the nature of this synapse and of the cholinergic action is not known.

Acetylcholine↗

PubMed2001

Differences in parasympathetic vasodilator and salivary responses in the cat submandibular gland between lingual and chorda-lingual nerve stimulation.

Experimental activation of parasympathetic vasodilatation and salivation in the submandibular gland by a "pseudoreflex" method has definite advantages over other commonly used methods. However, it is unclear which stimulation sites allow for avoidance of direct activation of the parasympathetic efferents to this gland. We examined this question in heavily anesthetized (alpha-chloralose and urethane), artificially ventilated, cervically vago-sympathectomized cats, using the intersection of the chorda-lingual nerve and the submandibular gland duct ("the intersection") as our reference point. Both vasodilatation and salivation evoked by electrical stimulation of the lingual nerve were abolished by section of the chorda-lingual nerve (10 mm proximal to the intersection), provided the stimulation site was distal to the intersection by 4 mm or more. This salivation was abolished by the muscarinic receptor antagonist, scopolamine. Thus, by careful choice of stimulation site, submandibular gland responses mediated solely by reflex parasympathetic mechanisms can be evoked by lingual nerve stimulation in this preparation.

Adrenergic alpha-Antagonists↗

PubMed1995

The endolymphatic sac: microsurgical topographic anatomy.

The endolymphatic sac is part of the membranous labyrinth; it plays an important role in the hearing mechanism. Injury to the endolymphatic sac may, over time, severely compromise hearing. The endolymphatic sac is located in a duplication of the dura of the posterior aspect of the petrous pyramid and is, therefore, in the surgical field of many neurosurgical operations performed on the posterolateral cranial base. The endolymphatic sac was exposed bilaterally in 10 anatomic specimens; the distance from the center of the sac to the posterior lip of the internal auditory meatus and to the XIth nerve in the jugular foramen was measured with a caliper. Also measured was the distance between the center of the sac and the closest point on the petrous ridge and the distance between that point and the petro-sigmoid intersection. The petro-sigmoid intersection was defined as the point at which the medial aspect of the sigmoid sinus intersects the lateral aspect of the petrous ridge. The dimensions of the sac were also recorded. On the average, the sac was found to be 15.7 mm posterosuperior (superolateral) to the XIth nerve in the jugular foramen (range, 11.0-18.5 mm) and 13.3 mm posterior (lateral) to the internal auditory meatus (range, 10.0-18.0 mm). The center of the sac was 24.1 mm (mean value) (range, 20.0-28.0 mm) in front of the petro-sigmoid intersection at a point 11.5 mm (mean value) (range, 8-17 mm) below the petrous ridge. The mean width and height of the sac were 3.83 (range, 2-6 mm) and 3.80 mm (range, 2.5-8 mm), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomy, Artistic↗

PubMed1981

Saturation constancy in surface colors.

The level of reflectance of pigmented surfaces observed in daylight affects saturation growth in different ways, depending on the wavelength of the samples. Numerical and matching judgments collected in previous experiments were replotted in families of monochromatic (constant hue) saturation power functions for blue, green, yellow, and red. For each hue the set of functions intersected at a point at which the colorimetric purity and saturation were invariant with reflectance. The points of intersection were: blues, 0.081 colorimetric purity (Pc) and 2.7 cromes; greens, 0.257 Pc and 4.6 cromes; yellows, 0.694 Pc and 8.3 cromes; and reds, 0.144 Pc and 3.6 cromes. A straight line fitted to these four intersecting points makes it possible to interpolate other intersecting points for other hues. Two additional experiments were designed to compare a function of saturation with a function of lightness for a set of different hues (heterochromatic functions). Observers judged saturation in one experiment and lightness in the other. Lightness grows linearly with reflectance, and saturation increases as the 0.5 power of Pc, suggesting a different perceptual discrimination for the two dimensions. The relation between changes in quantity and percentage of color perceived was tested in an additional experiment. Observers assigned the following saturation values to the samples with Pc close to the converging points: 13% of color for blues, 20% for reds, 25% for greens, and 40% for yellows.

Color↗

PubMed2024

Identification of cuproptosis-realated key genes and pathways in Parkinson's disease via bioinformatics analysis.

INTRODUCTION: Parkinson's disease (PD) is the second most common worldwide age-related neurodegenerative disorder without effective treatments. Cuproptosis is a newly proposed conception of cell death extensively studied in oncological diseases. Currently, whether cuproptosis contributes to PD remains largely unclear. METHODS: The dataset GSE22491 was studied as the training dataset, and GSE100054 was the validation dataset. According to the expression levels of cuproptosis-related genes (CRGs) and differentially expressed genes (DEGs) between PD patients and normal samples, we obtained the differentially expressed CRGs. The protein-protein interaction (PPI) network was achieved through the Search Tool for the Retrieval of Interacting Genes. Meanwhile, the disease-associated module genes were screened from the weighted gene co-expression network analysis (WGCNA). Afterward, the intersection genes of WGCNA and PPI were obtained and enriched using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Subsequently, the key genes were identified from the datasets. The receiver operating characteristic curves were plotted and a PPI network was constructed, and the PD-related miRNAs and key genes-related miRNAs were intersected and enriched. Finally, the 2 hub genes were verified via qRT-PCR in the cell model of the PD and the control group. RESULTS: 525 DEGs in the dataset GSE22491 were identified, including 128 upregulated genes and 397 downregulated genes. Based on the PPI network, 41 genes were obtained. Additionally, the dataset was integrated into 34 modules by WGCNA. 36 intersection genes found from WGCNA and PPI were significantly abundant in 7 pathways. The expression levels of the genes were validated, and 2 key genes were obtained, namely peptidase inhibitor 3 (PI3) and neuroserpin family I member 1 (SERPINI1). PD-related miRNAs and key genes-related miRNAs were intersected into 29 miRNAs including hsa-miR-30c-2-3p. At last, the qRT-PCR results of 2 hub genes showed that the expressions of mRNA were up-regulated in PD. CONCLUSION: Taken together, this study demonstrates the coordination of cuproptosis in PD. The key genes and miRNAs offer novel perspectives in the pathogenesis and molecular targeting treatment for PD.

Humans↗

PubMedDate not supplied

The fluorescence mechanism of 5-methyl-2-pyrimidinone: an ab initio study of a fluorescent pyrimidine analog.

The photophysically important potential energy surfaces of the fluorescent pyrimidine analog 5-methyl-2-pyrimidinone have been explored using multireference configuration-interaction ab initio methods at three levels of dynamical correlation, all of which support a fluorescence mechanism. At vertical excitation S1 (dark, n(N)pi*) and S2 (bright, pipi*) are almost degenerate at 4.4 eV, with S3 (dark, n(O)pi*) at 5.1 eV. The excited system can follow the S1-S2 seam of conical intersections, accessible from the Franck-Condon region, to its minimum and then evolve from this conical intersection on the S1 (pipi*) surface to a global minimum. At lower levels of correlation, the S1 surface shows two minima separated by a barrier of up to 0.18 eV. The secondary minimum found at the lower levels of correlation becomes the global minimum with higher correlation. The S1 population at this minimum can be trapped from accessing the lowest energy S0-S1 (pipi*/gs) conical intersection by an energy gap at least 0.3-0.4 eV higher than the S1 minimum. The calculated emission energy from this minimum is 2.80 eV. Gradient pathways connecting important S1 geometries are presented, as well as other excited state conical intersections.

Fluorescence↗

PubMed1996

The safety of older pedestrians at signal-controlled crossings.

The extent to which pedestrians checked for oncoming traffic before crossing signal-controlled intersections on busy city streets was observed. Contrary to the portrayal of older pedestrians as being less aware of the traffic environment, pedestrians over the age of fifty were the most cautious, especially under dangerous traffic conditions. Older pedestrians were least likely to use other pedestrians as "guides" to safety and, instead, checked for oncoming traffic themselves before crossing. There was an overall tendency for pedestrians to check for oncoming traffic, the fewer the number of other pedestrians crossing the intersection. "Diffusion of responsibility" and "safety in numbers" explanations were offered to account for this. Wide intersections elicited more traffic checking than narrow intersections only if traffic conditions were hazardous.

Accidents, Traffic↗

PubMed2004

Isoleucine requirements and ratios in starting (7 to 11 kg) pigs.

Two experiments were conducted to refine the Ile needs in 7- to 11-kg pigs. In Exp. 1, 1,680 pigs were fed a 1.25% digestible Lys diet containing 7.5% spray-dried blood cells (as-fed basis) with supplemental crystalline Ile (0.06% increments) to generate seven levels of apparent digestible Ile (0.47 to 0.83%). There were 12 replicates of each treatment with 20 pigs per pen, and treatments were imposed at an initial BW of 7 kg and continued for 16 d. Responses in ADG, ADFI, G:F, and plasma urea nitrogen (PUN) were quadratic (P < 0.01) over the 16-d period. Data were fitted to both a single-slope broken line and a quadratic fit, and when the quadratic response curve was superimposed on the broken line, the points at which the quadratic curve first intersected the plateau of the broken line occurred at 0.70, 0.73, 0.66, and 0.65% digestible Ile for ADG, ADFI, G:F, and PUN, respectively. Using the ADG and ADFI obtained at this intersection point resulted in an estimate of 9.1 mg of digestible Ile per gram of weight gain. In Exp. 2, 1,840 pigs were fed similarly composed diets, except that digestible Lys was lowered in six diets to 1.10% by decreasing soybean meal. Crystalline Ile was supplemented at 0.09% increments to generate six levels of digestible Ile (0.37 to 0.83%). A seventh diet contained 1.25% digestible Lys by supplementing the 0.83% digestible Ile diet with 0.19% L-Lys HCl to verify that 1.10% digestible Lys was deficient for these pigs. There were 12 replicates of each treatment with 22 pigs per pen, and treatments imposed at an initial BW of 7 kg and continued for 16 d. Supplementation of Lys to the 0.83% digestible Ile diet (1.10 vs. 1.25% digestible Lys) did not affect ADG (260 vs. 264 g/d, P = 0.60) and ADFI (359 vs. 343 g/d, P = 0.20), whereas G:F (725 vs. 774 g/kg, P < 0.01) was improved by increasing dietary Lys. Responses in ADG, ADFI, and G:F to the first six diets were quadratic (P < 0.01) over the 16-d period. The points at which the quadratic curve first intersected the plateau of the broken line occurred at 0.686, 0.638, and 0.684% digestible Ile for ADG, ADFI, and G:F, respectively. Using the ADG and ADFI obtained at this intersection point results in an estimate of 9.9 mg of digestible Ile per gram of weight gain. These results suggest that although the percent digestible Ile requirement and digestible Ile:Lys ratio for starter (7 to 11 kg) pigs may be higher than 1998 NRC recommendations, the requirement may be lower than current recommendations when taking gain and feed intake into account.

Animal Feed↗

PubMedDate not supplied

Neighborhood design and rates of walking and biking to elementary school in 34 California communities.

PURPOSE: This study evaluates the relationship between neighborhood design and rates of students walking and biking to elementary school. DESIGN: Pairwise correlations and multiple regression models were estimated based on a cross-sectional study of elementary schools and their surrounding neighborhoods. Setting and Subjects. Thirty-four (23%) of 150 California public elementary schools holding October 1999 Walk to School Day events participated in the study. MEASURES: Teachers asked fifth-grade students how they arrived to school 1 week before Walk to School Day. 1990 U.S. Census data measured population density and number of intersections per street mile, whereas 1998-1999 California Department of Education data measured school size, the percentage of students receiving public welfare, and the percentage of students of various ethnicities. RESULTS: Population density (p = .000) and school size (p = .053) were significantly associated with walking and biking rates in regression models controlling for number of intersections per street mile, the percentage of students receiving public welfare, and the percentage of students of various ethnicities. The number of intersections per street mile was associated with walking and biking rates in pairwise correlations (p = .003) but not in regression models. CONCLUSIONS: The results support the hypothesis that the walking and biking rates are higher in denser neighborhoods and to smaller schools but do not support the hypothesis that rates are higher in neighborhoods with a high number of intersections per street mile. We suggest that detailed data for a larger sample of students would allow statistical models to isolate the effect of specific design characteristics.

Bicycling↗

PubMed2003

Direction of foot force for pushes against a fixed pedal: variation with pedal position.

The force that healthy humans generated against a fixed pedal was measured and compared with that predicted by four models. The participants (n = 11) were seated on a stationary bicycle and performed brief pushing efforts against an instrumented pedal with the crank fixed. Pushes were performed to 10 force magnitude targets and at 12 crank angles. The increasing magnitude portion of the sagittal-plane force path for each push effort was fitted with a line to determine the direction of the muscle component of the foot force. Those directions varied systematically with the position of the pedal (crank angle) such that the force path lines intersected a common region superior and slightly anterior to the hip. The ability of four models to predict force path direction was tested. All four models captured the general variation of direction with pedal position. Two of the models provided the best performance. One was a musculoskeletal model consisting of nine muscles with parameters adjusted to provide the best possible fit. The other model was derived from (a) observations that the lines-of-action of the muscle component of foot force tended to intersect in a common region near the hip, and (b) the corresponding need for foot force to intersect the center-of-mass during walking. Thus, this model predicted force direction at each pedal position as that of a line intersecting the pedal pivot and a common point located near the hip (divergent point). The results suggest that the control strategy employed in this seated pushing task reflects the extensive experience of the leg in directing force appropriately to maintain upright posture and that relative muscle strengths have adapted to that pattern of typical activation.

Adult↗

PubMed2003

Perception-based road hazard identification with Internet support.

One of the most important tasks faced by highway agencies is identifying road hazards. Agencies use crash statistics to detect road intersections and segments where the frequency of crashes is excessive. With the crash-based method, a dangerous intersection or segment can be pointed out only after a sufficient number of crashes occur. A more proactive method is needed, and motorist complaints may be able to assist agencies in detecting road hazards before crashes occur. This paper investigates the quality of safety information reported by motorists and the effectiveness of hazard identification based on motorist reports, which were collected with an experimental Internet website. It demonstrates that the intersections pointed out by motorists tended to have more crashes than other intersections. The safety information collected through the website was comparable to 2-3 months of crash data. It was concluded that although the Internet-based method could not substitute for the traditional crash-based methods, its joint use with crash statistics might be useful in detecting new hazards where crash data had been collected for a short time.

Accidents, Traffic↗

PubMed2006

Limitations of clinical utility of growth hormone stimulating tests in diagnosing children with short stature.

OBJECTIVE: The diagnosis of growth hormone (GH) deficiency (GHD) is routinely based on the results of two stimulating tests performed with different stimuli. Arbitrarily established, equal cutoff levels for the tests with different pharmacological stimuli, as well as a relatively high incidence of falsely decreased (FD) response in the tests have been reported. Falsely decreased GH response in one of the two performed tests does not exclude FD response in the second one, so, it seems very important to assess the incidence of FD response in both GH stimulating tests. SUBJECTS AND METHODS: The analysis comprised the results of two GH stimulating tests (the 1st one with clonidine, the 2nd one with either insulin or glucagon) performed in 780 short children. RESULTS: The mean GH peak in the test with clonidine was significantly higher than that in both other tests (p<0.01). The rate of decreased GH secretion was 48.7 % in the test with clonidine, 80.5 % in the test with insulin and 81.5 % in the test with glucagon. Similar frequency of normal and subnormal test results was obtained for the cut-off value for the tests with insulin and with glucagon at the level of 6.4 ng/ml. The correlation between the results of the two tests as performed in particular patients was weak (r=0.27; p<0.05). Following cases of test results were found: 1. both results normal (1st NT, 2nd NT) in 117 patients (15.0 %), 2. 1st result normal, while the 2nd one falsely decreased (1st NT, 2nd FD) in 283 (36.3 %), 3. reverse situation (1st FD, 2nd NT) in 62 (7.9 %), 4. both results decreased in 318 (40.8 %), either truly (1st TD, 2nd TD) or falsely (1st FD, 2nd FD) - with unknown incidence. The following incidences (probabilities - P) result from the above data: A. P(1st NT, 2nd NT) = P(1st NT) intersection P(2nd NT) = 0.150; B. P(1st NT, 2nd FD) = P(1st NT) intersection P(2nd FD) = 0.363; C. P(1st FD, 2nd NT) = P(1st FD) intersection P(2nd NT) = 0.079. The expression (B intersection C)/A was calculated by transforming the right side of the equations: (B x C)/A = 0.192. Thus, 19.2 %, out of all 780 patients, i.e., 150 children (47.2 % of 318 patients, assessed as GH-deficient), could have both test results FD. CONCLUSIONS: The observed differences in GH response to particular pharmacological stimuli, as well as the high incidence of falsely decreased GH response in the two stimulating tests, should be taken into account in qualifying short children to GH therapy.

Adolescent↗

PubMedDate not supplied

A theoretical analysis of cast wedging with practical applications.

Cast wedging using vector and geometrical analysis demonstrated that the open wedge produces distraction of the fracture, the closing wedge shortening, and that the opening--closing wedge can perfectly correct skeletal deformity. The level of wedging should lie at the axis intersection, i.e., at the intersection of the long axes of the 2 major fracture fragments. An open wedge at the axis intersection is recommended for tibial shaft fractures immobilized with long leg casts; an opening--closing wedge at the axis intersection, for fractures immobilized with "pins and plaster".

Bone Nails↗

PubMed1994

Carbon monoxide exposures inside an automobile traveling on an urban arterial highway.

Carbon monoxide (CO) exposures were measured inside a motor vehicle during 88 standardized drives on a major urban arterial highway, El Camino Real (traffic volume of 30,500-45,000 vehicles per day), over a 13-1/2 month period. On each trip (lasting between 31 and 61 minutes), the test vehicle drove the same 5.9-mile segment of roadway in both directions, for a total of 11.8 miles, passing through 20 intersections with traffic lights (10 in each direction) in three California cities (Menlo Park, Palo Alto, and Los Altos). Earlier tests showed that the test vehicle was free of CO intrusion. For the 88 trips, the mean CO concentration was 9.8 ppm, with a standard deviation of 5.8 ppm. Of nine covariates that were examined to explain the variability in the mean CO exposures observed on the 88 trips (ambient CO at two fixed stations, atmospheric stability, seasonal trend function, time of day, average surrounding vehicle count, trip duration, proportion of time stopped at lights, and instrument type), a fairly strong seasonal trend was found. A model consisting of only a single measure of traffic volume and a seasonal trend component had substantial predictive power (R2 = 0.68); by contrast, the ambient CO levels, although partially correlated with average exposures, contributed comparatively little predictive power to the model. The CO exposures experienced while drivers waited at the red lights at an intersection ranged from 6.8 to 14.9 ppm and differed considerably from intersection to intersection.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution, Indoor↗