Intraocular lens materials and styles: a review

OBJECTIVE: To compare criteria for coronary revascularization developed by the expert panel process and by decision analysis. METHOD: We reviewed the medical records of 3080 chronic stable angina patients who either underwent coronary artery bypass graft surgery (CABG) or percutaneous transluminal coronary angioplasty (PTCA) and determined the agreement between appropriateness ratings made by two expert physician panels, one from the United States and the second from The Netherlands. We also evaluated the agreement between these panels' appropriateness ratings and a decision analytic model's effectiveness categories. RESULTS: There was poor agreement between U.S. and Dutch panel appropriateness ratings for PTCA (kappa = 0.03) and slight agreement for bypass surgery (kappa = 0.18). Dutch ratings had substantial agreement with the decision analytic models effectiveness categories for both PTCA and CABG (kappa = 0.83 and 0.79, respectively) whereas there was no systematic agreement between U.S. ratings and the decision analytic model for PTCA and poor agreement for CABG (kappa = 0.00 and 0.18, respectively). CONCLUSIONS: Although the level of agreement between expert panels and decision analysis on when a procedure is appropriate or effective may vary by procedure and the strength of the scientific evidence, we found that Dutch physicians agree much more strongly with decision analysis than U.S. physicians.     

Locus of control, coping behaviors, and performance in a stress setting: a longitudinal study

Examined the relationship between managerial locus of control (Rotter's Internal–External Control Scale), perceived stress (Subjective Stress Scale), coping behaviors (task- vs emotion-centered as defined in the R. L. Kahn et al 1964 typology), and performance (credit ratings). 90 small business owner-managers participated in 2 data collection phases over a 2?-yr interval following the effects of a major disaster. Internals were found to perceive less stress, employ more task-centered coping behaviors, and employ fewer emotion-centered coping behaviors than externals. Successful internals became more internal, whereas unsuccessful externals became more external over the 2?-yr interval. Changes in performance were related to changes in locus of control. The nature of locus of control as a possible cause of task behavior and as an effect of environmental experience is examined. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High power lens with a measurement water cell

A simple water cell can be used to increase the range of an ordinary lensometer by about three times by using an application of Snell's law. This technique can be very useful in low vision applications where other methods of measuring high plus ophthalmic lenses are always cumbersome and time consuming and sometimes inaccurate or inconclusive.     

Theoretical and practical performance of a concentric bifocal intraocular implant lens

Some results from a survey of 43 patients who had a monofocal intra-ocular-lens (IOL) in one eye and a concentric bifocal intra-ocular-lens in the fellow eye are reported. Twenty patients with 6/9 or better post-operative visual acuity in both eyes, participated in the main part of the study. Optical transfer functions for the bifocal lens showed that, compared to an optimal single-vision correction, there is a 50% contrast degradation of the distance retinal image across all spatial frequencies above around 3 c/deg. For the patients in the main study, there was a close correspondence between practical measurement of contrast sensitivity and the theoretical predictions of the modulation transfer functions. Measuring contrast sensitivity proved an effective means of assessing misalignment of the bifocal IOLs.     

Emotional labor, strain, and performance: Testing reciprocal relationships in a longitudinal panel study.

Models of emotional labor suggest that emotional labor leads to strain and affects job performance. Although the link between emotional labor, strain, and performance has been well documented in cross-sectional field studies, not much is known about the causal direction of relationships between emotional labor, strain, and performance. Goal of the present study was therefore to test the direction of effects in a two-wave longitudinal panel study using a sample of 151 trainee teachers. Longitudinal lagged effects were tested using structural equation modeling. Results revealed that the emotional labor strategy of surface acting led to increases in subsequent strain while deep acting led to increases in job performance. In contrast, there was no indication of reverse causation: Neither strain nor job performance had a significant lagged effect on subsequent surface or deep acting. Overall, results support models of emotional labor suggesting that surface and deep acting causally precede individual and organizational well-being. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association between air pollution and low birth weight: a community-based study

The relationship between maternal exposure to air pollution during periods of pregnancy (entire and specific periods) and birth weight was investigated in a well-defined cohort. Between 1988 and 1991, all pregnant women living in four residential areas of Beijing were registered and followed from early pregnancy until delivery. Information on individual mothers and infants was collected. Daily air pollution data were obtained independently. The sample for analysis included 74,671 first-parity live births were gestational age 37-44 weeks. Multiple linear regression and logistic regression were used to estimate the effects of air pollution on birth weight and low birth weight (< 2,500 g), adjusting for gestational age, residence, year of birth, maternal age, and infant gender. There was a significant exposure-response relationship between maternal exposures to sulfur dioxide (SO2) and total suspended particles (TSP) during the third trimester of pregnancy and infant birth weight. The adjusted odds ratio for low birth weight was 1.11 (95% CI, 1.06-1.16) for each 100 micrograms/m3 increase in SO2 and 1.10 (95% CI, 1.05-1.14) for each 100 micrograms/m3 increase in TSP. The estimated reduction in birth weight was 7.3 g and 6.9 g for each 100 micrograms/m3 increase in SO2 and in TSP, respectively. The birth weight distribution of the high-exposure group was more skewed toward the left tail (i.e., with higher proportion of births < 2,500 g) than that of the low-exposure group. Although the effects of other unmeasured risk factors cannot be excluded with certainty, our data suggests that TSP and SO2, or a more complex pollution mixture associated with these pollutants, contribute to an excess risk of low birth weight in the Beijing population.     

Temperature regulation during exercise in water and air

Four healthy subjects were studied during exercise in water, using a swimming flume, and in air, on a stationary bicycle ergometer at mean skin temperatures of 30 and 33 degrees C, respectively. Measurements included rectal (Tre), esophageal (Tes), and mean skin (Ts) temperatures, metabolic energy liberation (M) and total heat production (H), maximal aerobic power output (Vo2 max), cardiac frequency and calculated peripheral tissue heat conductance (K). The results showed that for a given M and Ts, Tes and Tre were about 0.4 degree C lower and the K values were consistently higher in swimming than in bicycling. The intersubject variability in Tes and Tre was reduced by considering relative (expressed as %VO2max) rather than absolute work load, but the differences in the body temperatures between the two types of exercise remained. It was concluded that during exercise in water where the capacity for heat dissipation is increased, the body core temperature (Tc) is maintained at a lower level due to the higher forced convective and conductive heat transfer from the skin in water. This reduces the heat storage at the beginning of exercise compared with conditions in air. The lower Tc-Ts gradient for a given H in swimming, which results in higher K values implies a greater skin circulation than during cycling in air.     

Distribution of striatin, a newly identified calmodulin-binding protein in the rat brain: an in situ hybridization and immunocytochemical study

The worm-like chain model has often been employed to describe the average conformation of long, intrinsically straight polymer molecules, including DNA. The present study extends the applicability of the worm-like chain model to polymers containing bends or sections of different flexibility. Several cases have been explicitly considered: (i) polymers with a single bend; (ii) polymers with multiple coplanar bends; (iii) polymers with two non-coplanar bends; and (iv) polymers comprised of sections with different persistence lengths. Expressions describing the average conformation of such polymers in terms of the mean-square end-to-end distance have been derived for each case. For cases (i) and (iv), expressions for the projection of the end-to-end vector onto the initial orientation of the chain are presented. The expressions derived here have been used to investigate DNA molecules with sequence-induced bending (A-tracts). Mean-square end-to-end distance values determined from a large number of A-tract containing DNA molecules visualized by scanning force microscopy resulted in an average bend angle of 13.5 degrees per A-tract. A similar study was performed to characterize the flexibility of double-strandedDNA molecules containing a single-stranded region. Analysis of their mean-square end-to-end distance yielded a persistence length of 1.3 nm for single-stranded DNA.     

Impression management, social desirability, and computer administration of attitude questionnaires: Does the computer make a difference?

G. J. Lautenschlager and V. L. Flaherty (1990) unexpectedly found that more socially desirable responding occurred on a computer version of an attitude and personality questionnaire than on a paper-and-pencil version. The present study attempted to replicate and extend their findings in a noncollege environment. Male Navy recruits (N?=?246) completed several questionnaires in either a computer-administered or paper-and-pencil condition and in either an anonymous or identified condition. Identified respondents had higher impression management and self-deceptive enhancement scores than anonymous respondents. Contrary to Lautenschlager and Flaherty's results, however, there was no systematic difference between computer and paper-and-pencil modes. It is concluded that computer and paper-and-pencil modes of administration yield similar responses on attitude questionnaires. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kinetics of peptide folding: computer simulations of SYPFDV and peptide variants in water

The folding of Ser-Tyr-Pro-Phe-Asp-Val (SYPFDV), and sequence variants of this peptide (SYPYD and SYPFD) are studied computationally in an explicit water environment. An atomically detailed model of the peptide is embedded in a sphere of TIP3P water molecules and its optimal structure is computed by simulated annealing. At distances from the peptide that are beyond a few solvation shells, a continuum solvent model is employed. The simulations are performed using a mean field approach that enhances the efficiency of sampling peptide conformations. The computations predict a small number of conformations as plausible folded structures. All have a type VI turn conformation for the peptide backbone, similar to that found using NMR. However, some of the structures differ from the experimentally proposed ones in the packing of the proline ring with the aromatic residues. The second most populated structure has, in addition to a correctly folded backbone, the same hydrophobic packing as the conformation measured by NMR. Our simulations suggest a kinetic mechanism that consists of three separate stages. The time-scales associated with these stages are distinct and depend differently on temperature. Electrostatic interactions play an initial role in guiding the peptide chain to a roughly correct structure as measured by the end-to-end distance. At the same time or later the backbone torsions rearrange due to local tendency of the proline ring to form a turn: this step depends on solvation forces and is helped by loose hydrophobic interactions. In the final step, hydrophobic residues pack against each other. We also show the existence of an off the pathway intermediate, suggesting that even in the folding of a small peptide "misfolded" structures can form. The simulations clearly show that parallel folding paths are involved. Our findings suggest that the process of peptide folding shares many of the features expected for the significantly larger protein molecules.     

Review of Mind and performance: a comparative study of learning in mammals, birds, and reptiles.

Reviews "Mind and performance: a comparative study of learning in mammals, birds, and reptiles," by Harold K. Fink (see record 1955-00447-000). One of the objectives of comparative psychology, as its name implies, is to compare the sensory and motor abilities of animals to those of man. Yet surprisingly few investigators have devoted themselves seriously to this problem. The present monograph describes a five-year research which examines the learning ability of seven species of mammals including man, chickens, and turtles and tortoises. In terms of the number of different species studied it is the most comprehensive of any of the truly comparative investigations of animal behavior. Learning efficiency is measured with a device called the "Arrow Maze," which is a kind of cross between the more orthodox type of maze and a four-way multiple-choice box. The book is well and simply written in language which can be understood by the intelligent layman and is at the same time acceptable to the technically trained psychologist. It is a comprehensive and significant contribution and will make an important addition to the literature of the field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

采矿方法研究与现场实验

本文从采矿方法研究及与此相关的现场实验内容、实验目的、初步步骤作简略介绍，并附有实例，其目的是促使比较复要开采技术条件的岩金矿山采矿方法研究达到更高的技术水平。     

Sunlight exposure and risk of lens opacities in a population-based study: the Salisbury Eye Evaluation project

CONTEXT: Exposure to UV-B radiation in sunlight has been shown to increase the risk of cataract formation in high-risk occupational groups, but risk to the population has not been quantified. OBJECTIVES: To determine the ocular exposure to UV-B radiation in sunlight for a population of older persons and to determine the association between UV-B and lens opacities. DESIGN: The Salisbury Eye Evaluation project, a population-based cohort of older adults. SETTING: Salisbury, Md. PARTICIPANTS: A total of 2520 community-dwelling 65-year-old to 84-year-old adults in Salisbury, Md, from 1993 to 1995, of whom 26.4% were African Americans. MAIN OUTCOME MEASURE: Association of photographically documented cortical opacity 3/16 or greater in at least 1 eye with ocular UV-B exposure, reported in Maryland sun-years of exposure. RESULTS: The odds of cortical opacity increased with increasing ocular exposure to UV-B (odds ratio [OR], 1.10; 95% confidence interval [CI], 1.02-1.20). The relationship was similar for women (OR, 1.14; 95% CI, 1.00-1.30) and for African Americans (OR, 1.18; 95% CI, 1.04-1.33). Analyses of the ocular dose by each age group after the age of 30 years showed no vulnerable age group, suggesting damage is based on cumulative exposure. CONCLUSIONS: Although this population of older Americans has relatively low ocular exposure to UV-B in sunlight, there is still an association between ocular exposure and increasing odds of cortical opacity. Our study found an association among African Americans, which, to our knowledge, has not been reported previously. All sex and racial groups would benefit from simple methods to avoid ocular sun exposure.     

Rabbit lens and retina phosphorylate glucose through a glucokinase-like enzyme: study in normal and spontaneously hyperglycemic animals

After having previously shown that some noninsulin-sensitive tissues (capillaries and optic nerve) phosphorylate glucose in a concentration-dependent manner through a glucokinase-like enzyme, here, we report data on glucose phosphorylation in rabbit lens and retina at various glucose concentrations (1, 5, 10, 25, 50, and 100 mmol/L). In the 3000 g supernatant of lens and retina homogenates from two separate groups of female albino rabbits ten animals in each group; 1.8-2.0 kg body weight; mean +/- SEM morning glycemia: 8.19 +/- 0.28 and 8.12 +/- 0.24 mmol/L, respectively) was assayed glucose phosphorylating activity (NADP reduction measured as change in optical density at 366 nm at pH 7.5). The enzyme activity did not reach the maximum at low glucose concentration (1 mmol/L), as it occurs in several tissues, but increased progressively in both tissues with the increase in glucose concentration. Values (mean +/- SEM) for lens were 0.197 +/- 0.031 nmol/min/mg protein at 1 mmol/L and 0.327 +/- 0.051 (the highest value) at 50 mmol/L glucose (+65.99%, p < 0.01; r = 0.31, p < 0.05). Values for retina were 36.02 +/- 2.12 at 1 mmol/L glucose and 42.48 +/- 2.79 (the highest value) at 25 mmol/L glucose (+17.93%, p < 0.001; r = 0.32, p < 0.05). These kinetic characteristics, somewhat reminiscent of those shown by hepatic glucokinase, are still more pronounced when we calculated the "glucokinase component," obtained by subtracting the activity at 1 mmol/L glucose (hexokinase component) from that at the highest glucose concentration (total glucose phosphorylating activity). In five rabbits of similar age and weight, with spontaneous hyperglycemia (mean +/- SEM morning glycemia: 11.71 +/- 0.60) glucose phosphorylation in the retina was lower than normal, value at pH 7.5 and 1 mmol/L glucose being 24.52 +/- 2.20 versus 36.02 +/- 2.12 of normal animals (-31.93%, p < 0.01). This, if occurs also in other tissues, could contribute to the hyperglycemia by reducing glucose utilization. In these animals, however, the glucose phosphorylating activity retained the responsivity to increasing glucose concentrations, with value at 100 mmol/L of 28.65 +/- 2.10, corresponding to + 16.84% over the value at 1 mmol/L (p < 0.01). Therefore, the actual glucose phosphorylation in the retina of these animals would depend both upon the enzyme level (which is reduced) and glucose concentration (which is increased). Due to the in vivo inhibition of the hexokinase component by glucose 6-phosphate, the glucokinase component in retina and lens may be predominant in vivo, making the stimulating effect of hyperglycemia much more important than it would appear from our in vitro data. This might play a role in the chronic diabetic complications.     

Hybrid bilayer membranes in air and water: infrared spectroscopy and neutron reflectivity studies

In this report we describe the fabrication and characterization of a phospholipid/alkanethiol hybrid bilayer membrane in air. The bilayer is formed by the interaction of phospholipid with the hydrophobic surface of a self-assembled alkanethiol monolayer on gold. We have characterized the resulting hybrid bilayer membrane in air using atomic force microscopy, spectroscopic ellipsometry, and reflection-absorption infrared spectroscopy. These analyses indicate that the phospholipid added is one monolayer thick, is continuous, and exhibits molecular order which is similar to that observed for phospholipid/phospholipid model membranes. The hybrid bilayer prepared in air has also been re-introduced to water and characterized using neutron reflectivity and impedance spectroscopy. Impedance data indicate that when moved from air to water, hybrid bilayers exhibit a dielectric constant and thickness that is essentially equivalent to hybrid bilayers prepared in situ by adding phospholipid vesicles to alkanethiol monolayers in water. Neutron scattering from these samples was collected out to a wave vector transfer of 0.25 A(-1), and provided a sensitivity to changes in total layer thickness on the order of 1-2 A. The data confirm that the acyl chain region of the phospholipid layer is consistent with that observed for phospholipid-phospholipid bilayers, but suggest greater hydration of the phospholipid headgroups of HBMs than has been reported in studies of lipid multilayers.     

Cochlear implant performance after reimplantation: a multicenter study

OBJECTIVE: This study compares auditory performance between original and replacement cochlear implants. STUDY DESIGN AND SETTING: Data from 18 U.S. cochlear implant programs were obtained by retrospective chart review. Patients received and returned subjective questionnaires. PATIENTS: Twenty-eight adults with once-functioning Nucleus 22 cochlear implants that failed received replacement Nucleus 22 cochlear implants in the same ears. MAIN OUTCOME MEASURES: Objective measures included sentence (CID Everyday Sentences or Iowa Sentences) and monosyllabic word (NU-6 Words or CNC Words) speech discrimination scores. Patients also rated and compared performance using subjective scales. RESULTS: Thirty-seven percent of patients had significantly higher sentence or word scores with their replacement cochlear implants than with their original implants, 26% had no significant change, and 37% had significantly poorer scores. Subjectively, 57% of patients reported that the performance of their replacement device was better or the same and 43% reported that it was poorer. There was no correlation between performance with the replacement cochlear implant and cause of the original device failure, duration of original device use before failure, surgical complications with either implantation, changes in electrode insertion depths, or preoperative variables, such as age, etiology, or duration of deafness. CONCLUSIONS: Speech recognition ability with a replacement cochlear implant may significantly increase or decrease from that with the original implant. Experienced cochlear implant patients facing reimplantation must be counseled regarding the possibility of differences in sound quality and speech recognition performance with their replacement device.     

bdGas carburizing of steel with furnace atmospheres formedin situ from methane and air and from butane and air

Carburizing experiments were conducted at 927°C (1700°F) and 843°C (1550°F) using furnace atmospheres formed from methane and air and from butane and air introduced directly into the carburizing furnace. Gas flow rates were low to promote equilibration of the reaction products within the furnace. The air flow rate was held constant while the methane or butane flow was automatically regulated to maintain a constant oxygen potential, as measured by a zirconia oxygen sensor, within the furnace. In comparing the results of these experiments with earlier results obtained using propane and air, several differences were noted: (a) The methane content of the furnace atmosphere, measured by infrared analysis, was about twice as great when methane was the feed gas rather than propane or butane. This was true despite the fact that the mean residence time of the gas within the furnace was greater in the methane experiments. Methane appears to be less effective than propane or butane in reducing the CO₂ and H₂O contents to the levels required for carburizing. (b) There was a greater tendency for the CO content of the furnace atmosphere to decrease at high carbon potentials when methane is used instead of propane or butane. The decrease in CO content is due to hydrogen dilution caused by sooting in the furnace vestibule. These differences in behavior make propane or butane better suited than methane forin situ generation of carburizing atmospheres. However, there is no difference in the amount of carburizing occurring at a specified carbon potential when methane, propane, or butane are used as the feed gas in this process. J.A.Pieprzak, formerly a member of the Engineering and Research Staff