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PubMed1999

Consistency of handwriting movements in dementia of the Alzheimer's type: a comparison with Huntington's and Parkinson's diseases.

Patients with dementia of the Alzheimer's type (DAT) and their matched controls wrote, on a computer graphics tablet, 4 consecutive, cursive letter 'l's, with varying levels of visual feedback: noninking pen and blank paper so that only the hand movements could be seen, noninking pen and lined paper to constrain their writing, goggles to occlude the lower visual field and eliminate all relevant visual feedback, and inking pen with full vision. The kinematic measures of stroke length, duration, and peak velocity were expressed in terms of consistency via a signal-to-noise ratio (M value of each parameter divided by its SD). Irrespective of medication or severity, DAT patients had writing strokes of significantly less consistent lengths than controls', and were disproportionately impaired by reduced visual feedback. Again irrespective of medication or severity, patients' strokes were of significantly less consistent duration, and significantly less consistent peak velocity than controls', independent of feedback conditions. Patients, unlike controls, frequently perseverated, producing more than 4 'l's, or multiple sets of responses, which was not differentially affected by level of visual feedback. The more variable performance of patients supports a degradation of the base motor program, and resembles that of Huntington's rather than Parkinson's disease patients. It may indeed reflect frontal rather than basal ganglia dysfunction.

Aged↗

PubMed1996

Isotope partitioning with Ascaris suum phosphofructokinase is consistent with an ordered kinetic mechanism.

Isotope partitioning and initial velocity studies have been used to study the kinetic mechanism of Ascaris suum phosphofructokinase (PFK) at pH 8.0 for the native enzyme (nPFK), and at pH 6.8 for a form of enzyme desensitized (dPFK) to hysteresis in the reaction time course, to ATP allosteric inhibition, and to F6P homotropic cooperativity. Complete trapping (P*max approximately equal to 100%) of the E:MgATP* complex as fructose (1-32P)-1, 6-bisophosphate for both enzyme forms is consistent with the previously proposed steady-state ordered mechanism [Rao, G.S.J., Harris, B.G., & Cook, P.F. (1987) J.Biol. Chem. 262, 14074-14079] with MgATP binding before fructose 6-phosphate (F6P). K'F6P values for trapping of MgATP of 0.54 +/- 0.09 mM for nPFK and 0.85 +/- 0.15 mM for dPFK were obtained. Saturating amounts of the heterotropic activator fructose 2, 6-bisphosphate (F26P2) gives no change in the trapping parameters for nPFK with a P*max of 100% and a K'F6P of 0.40 +/- 0.06 mM. For dPFK, however, F26P2 causes a decrease in both parameters, giving a P*max of 54% and a K'F6P of 0.26 +/- 0.07 mM. The partial trapping of E:MgATP* in the presence of F26P2 for dPFK suggests that the activator changes the kinetic mechanism from an ordered to a random binding of substrates. Initial velocity studies confirm the change in mechanism. Uncompetitive inhibition by arabinose 5-phosphate (Ara5P), a dead-end inhibitory analog of F6P, versus MgATP for nPFK in the absence and presence of F26P2 is consistent with an ordered mechanism with MgATP adding to enzyme prior to F6P. An uncompetitive pattern is also obtained with dPFK for Ara5P versus MgATP in the absence of F26P2, but the pattern becomes noncompetitive in the presence of F26P2, consistent with a change to a random mechanism. No trapping of the E:[14C]F6P complex could be detected, indicating either that the E:[14C]F6P complex does not form in a significant amount under the conditions used or that the off-rate for F6P from enzyme is much faster than the net rate constant for formation of the first product, FBP. The data are consistent with a predominantly ordered mechanism with MgATP binding prior to F6P. The minor pathway with MgATP dissociating from the E:F6P:MgATP ternary complex becomes apparent for the dPFK in the presence of F26P2.

Adenosine Triphosphate↗

PubMed1999

Process control in a high shear mixer-granulator using wet mass consistency: the effect of formulation variables.

This work investigates the relationships between the wet mass consistency/viscosity of samples prepared in a mixer-granulator and physical properties of the dry granules produced from the wet mass; namely, size distribution, bulk density (Hausner ratio), friability, and flow avalanching behavior. The correlation between the consistency of the wet mass and the downstream dry granule properties confirms that consistency is the key parameter to control in wet granulation by mechanical agitation. Variations in the formulation affect the dimensionless power relationship of the mixer-granulator considered; that is, the equivalence between wet mass consistency and mixer net power consumption, which is actually the parameter used to monitor the wet granulation process. The same variations in formulation also affect the relationships between wet mass consistency and dry granule properties.

Algorithms↗

PubMed2006

Electrochemical control of the structure of two-dimensional supramolecular organization consisting of phthalocyanine and porphyrin on a gold single-crystal surface.

Two-component adlayers consisting of cobalt(II) phthalocyanine (CoPc) and a metalloporphyrin such as 5,10,15,20-tetraphenyl-21H,23H-porphine copper(II) (CuTPP), 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine copper(II) (CuOEP), or 5,10,15,20-tetraphenyl-21H,23H-porphine cobalt(II) (CoTPP) were prepared by immersing either an Au(111) or Au(100) substrate in a benzene solution containing those molecules. The mixed adlayers thus prepared were investigated in 0.1 M HClO4 by cyclic voltammetry (CV) and in situ scanning tunneling microscopy (STM). The composition of the mixed adlayer consisting of CoPc and CuTPP molecules was found to vary with immersion time. CoPc molecules displaced CuTPP molecules during the modification process with increasing immersion time, and the CuTPP molecules were completely displaced by CoPc molecules in the mixed solution after a prolonged modification time, during which the underlying Au(100) substrate underwent phase transition from the reconstructed (hex) lattice to the unreconstructed (1 x 1) lattice. The two-component adlayer of CoPc and CuTPP was found to form a supramolecular adlayer with the constituent molecules arranged alternately on Au(100)-(hex). The striped structure was stable on Au(100)-(hex) at or near the open circuit potential (OCP), whereas the mixed adlayer was disordered on Au(100)-(1 x 1) at potentials more positive than OCP, where the phase transition of the arrangement of underlying Au atoms (i.e., the lifting of reconstruction) was induced electrochemically. A similar two-component supramolecular adlayer consisting of CoPc and CuTPP was formed on Au(111). A highly ordered, compositionally disordered adlayer of CoTPP and CuTPP was formed on Au(100)-(hex), suggesting that the adlayer structure is independent of the coordinated central metal ion for the formation of supramolecular nanostructures composed of those molecules. A supramolecular organization of CoPc and CuOEP was also found on Au(111). The surface mobility and the molecular reorganization of CoPc and CuOEP on Au(111) were tuned by modulation of the electrode potential. It is concluded that molecular assemblies of the two-component structure consisting of phthalocyanine and porphyrin were controlled not only by the crystallographic orientation of Au but also by the modulation of electrochemical potential.

Journal Article↗

PubMed2000

The reliability and internal consistency of an Internet-capable computer program for measuring utilities.

OBJECTIVE: The purpose of this study was to assess the reliability and internal consistency of measurements of utilities performed with a computer program (iMPACT2) designed for Internet surveys and Internet patient decision-support systems. METHODS: We implemented the Internet Multimedia Preference Assessor Construction Tool, version 2 (iMPACT2) program using the combination of a web server, HTML files, and a web-accessible database. The program randomized subjects, screened their responses for missing data and failures of internal consistency, assisted patients with resolving certain inconsistencies, and, upon a subject's completion of the protocol, provided a report of results to the research assistant administering the program. To validate the iMPACT2 program, we recruited 60 healthy community volunteers and elicited preferences in a research-lab setting using a visual analog scale (VAS) and the standard gamble (SG) for subject's current health and three hypothetical states. For purposes of comparison, we also administered a Short Form-12 (SF-12) health-assessment questionnaire. Subjects used the computer software on two occasions separated by 2-4 weeks of time. RESULTS: Visual analog scale and standard gamble ratings for subjects' current health were reliable (intraclass correlation coefficient (ICC) of 0.82 and 0.84 (two outliers excluded -0.60 without exclusions), respectively) were comparable with the reliability of the Physical and Mental Component scales of the SF-12 (ICCs of 0.84 and 0.75, respectively). Subjects could easily discriminate between hypothetical states (D scores 0.74 for SG and 0.90 for VAS), and 94% had a completely internally consistent ordering of preference ratings for states. CONCLUSIONS: iMPACT2 produces measurements of standard gamble utilities that are reliable and have a high degree of internal consistency. Procedures for assessment of utilities developed for desktop computer programs can be translated to software designed for the Internet, facilitating the use of utilities and endpoints in clinical trials and development of web-based decision-support applications for patients. However, further testing, including direct comparisons with traditional interviewer administered utility elicitation protocols, is needed.

Analysis of Variance↗

PubMed2001

Are risk and protective factors for substance use consistent across historical time?: national data from the high school classes of 1976 through 1997.

Researchers have seldom examined whether risk and protective factors are consistently linked to substance use across historical time. Using nationally representative data collected from 22 consecutive cohorts of high school seniors (approximate N = 188,000) from the Monitoring the Future (MTF) project, we investigated whether correlates of substance use changed across historical time. We found a high degree of consistency across historical time in predictors of past month cigarette use, past month alcohol use, past year marijuana use, and past year cocaine use. Some predictors such as religiosity, political beliefs, truancy, and frequent evenings out were consistently linked to substance use. The consistency of other predictors such as region, parental education, and college plans was contingent in part upon historical time period, the particular substance, and its level of use.

Adolescent↗

PubMed1991

State-outcome consistency in smoking relapse crises: a reversal theory approach.

Previous investigations of smoking relapse crises have found limited within-subject consistency. Several investigators have suggested that greater consistency might be observed if situations were described phenomenologically. Reversal theory provides one phenomenological framework. Two relapse crises from each of 49 ex-smokers were compared, using reversal theory constructs. Maintaining abstinence in both crises was consistently associated with being in serious-minded (telic) and conformist states. Smoking in both crises was consistently associated with being in playful (paratelic) or negativistic states. Crises with different outcomes occurred in different state combinations. The findings suggest that coping strategies should be state-tailored for optimal effectiveness.

Adaptation, Psychological↗

PubMed1988

Understanding the central processing limit in consistent-mapping visual search tasks.

Effects of load (i.e., the number of stimuli in the display) have been observed in multiple-frame studies using a consistent mapping of stimuli to responses (e.g., Fisher, 1982, 1984). In a series of four experiments, it is shown that these effects are not the consequence of differences across the high- and low-load conditions in either decision noise or peripheral masking. Additionally, it is shown that of two modes of limited capacity (a limited-channel and divided-capacity model) considered as possible explanations of load effects in tasks where subjects are required to locate a target, only one--the limited-channel model--is consistent with the results from all three location tasks. Finally, it is argued that the limited-channel model predicts not only the behavior observed in the four consistent-mapping experiments reported in this article but also the behavior observed in several related consistent-mapping tasks (Kleiss & Lane, 1986; Shiffrin & Gardner, 1972).

Attention↗

PubMed1998

Does consistent scene context facilitate object perception?

The conclusion that scene knowledge interacts with object perception depends on evidence that object detection is facilitated by consistent scene context. Experiment 1 replicated the I. Biederman, R. J. Mezzanotte, and J. C. Rabinowitz (1982) object-detection paradigm. Detection performance was higher for semantically consistent versus inconsistent objects. However, when the paradigm was modified to control for response bias (Experiments 2 and 3) or when response bias was eliminated by means of a forced-choice procedure (Experiment 4), no such advantage obtained. When an additional source of biasing information was eliminated by presenting the object label after the scene (Experiments 3 and 4), there was either no effect of consistency (Experiment 4) or an inconsistent object advantage (Experiment 3). These results suggest that object perception is not facilitated by consistent scene context.

Adult↗

PubMed2002

Stress-related immune changes in middle-aged and older women: 1-year consistency of individual differences.

This study reviews prior research and reports longer-term consistency of stress-related immune variables in middle-aged and older women who performed mental math and speech tasks 2 times 1 year apart. Leukocyte subsets, mitogen-induced lymphocyte proliferation, and natural killer cell activity were measured at baseline, after tasks, and after 30-min recovery. Epstein-Barr virus (EBV) antibody titers were assessed at baseline. Pearson coefficients and standardized maximum-likelihood estimates of year-to-year covariances for leukocyte subsets and EBV titers showed moderately high to high baseline and posttask consistency and lower recovery consistency; consistency for other functional immune assays and reactivity scores for all variables was moderate to low. Results support longitudinal study of psychosocial context effects on tonic immune function and posttask scores.

Aged↗

PubMed1989

Trans-situational consistency in smoking relapse.

This article explores the question of consistency in ex-smokers' experiences of temptation to smoke. Data were collected from 57 ex-smokers who called a relapse-prevention hotline on two occasions. Relapse situations were classified through cluster analysis and were also coded on McKennel's Smoking Motivation factors. Cognitive and behavioral coping efforts were recorded. Only modest trans-situational consistency was observed. The two relapse episodes did not systematically fall into the same cluster. Data suggested that social aspects of relapse situations might be most consistent. Behavioral coping showed modest trans-situational consistency, whereas cognitive coping showed no stability. The implications of these findings for the prospect of individually tailored interventions are discussed.

Adaptation, Psychological↗

PubMed2003

The relational-interdependent self-construal, self-concept consistency, and well-being.

Examination of the assumptions underlying consistency perspectives in social and personality psychology reveals that they are based on an independent, individualistic view of the self. If the self is constructed as relational or interdependent with others, consistency may be less important in social behavior and well-being. Using a variety of measures of well-being, the studies showed that there is a weaker relation between consistency and well-being for individuals with a highly relational self-construal than for those with a low relational self-construal. Study 3 examined the association between the self-construal, consistency, authenticity, and well-being. These findings reveal the importance of a cultural analysis of theories of the self, personality, and well-being for further theory development.

Adaptation, Psychological↗

PubMed2001

Consistency of voice produced by patients with adductor spasmodic dysphonia: a preliminary investigation.

Adductor spasmodic dysphonia (ADSD) is an idiopathic focal laryngeal movement disorder causing involuntary and uncontrollable spasms in the vocal fold musculature, primarily during voice onset. Although phonatory instability has been reported through clinical observation and empirical study, no examination of phonatory performance consistency in ADSD has been done. Phonatory instability refers to phonatory unsteadiness and has been previously defined by the presence of acoustic aberrations during speech. Performance consistency pertains to variations in these phonatory aberrations across repeated trials or over time. This study focused on the phonatory performance consistency of those with ADSD by using three acoustic measures of phonatory instability. Twenty patients with ADSD were recorded during three trials of reading a standard passage. Eight of the 20 patients were recorded twice during two separate recording sessions held approximately 6 months apart. The number of phonatory breaks, frequency shifts, and aperiodic segments were the dependent measures. Data were subjected to inferential statistical analysis to test for significant differences among the measures in two conditions: across three trials produced within one recording session and across multiple trials produced during two distinct recording sessions. No significant differences were found for any of the measures either as a function of trials recorded on the same day or across the two recording sessions. The data suggest a need for describing phonatory instability and performance consistency as separate entities with regard to neurological voice disorders.

Adult↗

PubMed1988

Perceptual categorization and consistency of synthesized (r-w) continua by adults, normal children and (r)-misarticulating children.

The purpose of this study was to determine if children who misarticulate (r) differ from normal children and adults in the perception of sound features that are produced correctly and incorrectly. Children with normal articulation, children who produced (r) misarticulations, and adults listened to synthesized child and adult (r-w) continua in two separate sessions, and to an adult (b-w) control continuum in one session. Perception was evaluated on the basis of measures of phonetic boundary location and the consistency of response to each stimulus in a continuum. The (r)-misarticulating children were found to be significantly less consistent than child and adult controls in responding to the (r-w) stimuli. Moreover, consistency scores were significantly higher for the adult continuum than for the child continuum. The performance of children was different from that of adults. Due to inconsistent performance, boundaries could not be computed for (r)-misarticulating children, but it was found that the boundaries for children in the control group were closer to the (r)-end of the continuum than those for adults. In the case of the (b-w) continuum, it was found that (r)-misarticulating children were significantly less consistent than adults. The phonetic boundaries of children were significantly closer to the (b)-end of the continuum than the boundary for adults. Thus, the results reveal that variability in stimulus response was influenced primarily by the productive ability of the subjects, whereas differences in stimulus categorization were influenced by the age of the subjects. The perceptual variability was most clearly reflected by responses to stimuli produced incorrectly, whereas categorization differences extended to sounds produced correctly.

Adult↗

PubMed2006

Consistently high urine specific gravity in adolescent American football players and the impact of an acute drinking strategy.

The purpose of this study was to determine whether high-school football players showed risks of fluid deficits during two-a-day training (Part 1), and whether implementing a drinking strategy could acutely improve the markers of hydration (Part 2). In Part 1, pre-training urine specific gravity (USG) and pre- and post-training body weight were measured at the morning session for 5 consecutive days of two-a-day practices to monitor the hydration status of 13 varsity players. The mean pre-training body weight was consistently lower (mean decrease of 0.5 kg, p<0.05) following the first day of measurement. Pre-training USG values remained consistently high each day (range for daily means: 1.022+/-0.003 to 1.024+/-0.005). Part 2 consisted of assessing hydration status in 46 varsity and junior varsity players prior to morning training during two-a-day training before and following implementing a drinking strategy. In association with the strategy, mean body weight increased 0.5 kg (p<0.01) and mean USG decreased from 1.021 to 1.016 (p<0.01) following the drinking protocol. The slight decline in body weight and consistently high USG (Part 1) suggested that standard fluid replacement strategies were less than optimal for a majority of the players. Implementing a drinking strategy appeared to improve hydration status based on changes in body weight and USG (Part 2).

Adolescent↗

PubMed2004

Analytic density-functional self-consistent-field theory of diblock copolymers near patterned surfaces.

Analytical solutions are derived for the density profiles and the free energies of compressible diblock copolymer melts (or incompressible copolymer solutions) near patterned surfaces. The density-functional self-consistent-field theory is employed along with a Gaussian chain model for bonding constraints and a random mixing approximation for nonbonded interactions. An analytical solution is rendered possible by expanding the chain distribution function around an inhomogeneous reference state with a nontrivial analytical solution, by retaining the linear terms, and by requiring consistency with the homopolymer limit. The density profiles are determined by both real and complex roots of a sixth-degree polynomial that may easily be obtained by solving a generalized eigenvalue problem. This analytical formulation enables one to efficiently explore the large nine-dimensional parameter space and can serve as a first approximation to computationally intensive studies with more detailed models. Illustrative computations are provided for uniform and patterned surfaces above the order-disorder transition. The results are consistent with the previous self-consistent-field calculations in that lamellar ordering appears near the surface above the order-disorder transition and the lamella order perpendicular or parallel to the surface depending on the commensurability between the periods of the surface pattern and the density oscillations.

Journal Article↗

PubMed2002

Comparison of inter- and intraobserver consistency for grading of esophagitis by expert and trainee endoscopists.

BACKGROUND: This study evaluated intra- and interobserver variability in the endoscopic scoring of esophagitis by using two grading schemes, the Los Angeles and Hetzel-Dent scales. METHODS: Three hundred twenty-five endoscopic photographs of esophagitis or healed esophagitis were randomly displayed twice to 9 endoscopist evaluators (4 experts, 5 trainees) by means of a CD-ROM. Evaluators scored each photograph by using both classification schemes. The analysis was based on the kappa (kappa) statistic as a measure of consistency. RESULTS: For trainees, intraobserver reproducibility was good (kappa = 0.436) when using the Los Angeles classification and marginal (kappa = 0.395) by using the Hetzel-Dent classification. For experts, intraobserver reproducibility was better by using both the Los Angeles (kappa = 0.545) and Hetzel-Dent classification (kappa = 0.552). Interobserver consistency for trainees was good when using both classifications (Los Angeles, kappa = 0.459; Hetzel-Dent, kappa = 0.427). Again, intraobserver reproducibility was better for experts when using both classifications (Los Angeles, kappa = 0.556, Hetzel-Dent, kappa = 0.571). By using the Los Angeles classification, only 5.1% and 7.5% of the photographs were interpreted to be more than 1 grade different from the mean grade for, respectively, experts and trainees. This same consistency was found by using the Hetzel-Dent classification scheme (experts 5.1%, trainees 10.2%). CONCLUSIONS: Reproducibility in grading esophagitis was good for both expert endoscopists and fellows, although there was greater consistency among the experts. Both the Los Angeles and Hetzel-Dent scoring systems are reproducible.

Esophagitis↗

PubMed1993

Accuracy and consistency of absolute pitch.

The accuracy and consistency of absolute pitch (AP) judgments have been measured on three subjects in two longitudinal studies separated by twenty years. The drifts and cyclical variations observed in the earlier study still persisted, and an investigation of two other subjects, one of whom was first studied forty years ago, suggests that they might undergo similar cyclical variations in their pitch perception. Pitch judgments also varied during the day. The detailed observations of these nonrandom fluctuations have been used to determine a value for the underlying consistency of the AP estimates. When the effects of the daytime variations and longer-term drifts were removed, the values for this consistency, as measured by the standard deviation, were calculated to be 3.1, 3.4, 3.7, 4.4, and 4.5 Hz for the five subjects. When an oscillator was used to produce the estimate, the consistency of the judgments was observed to depend on the accuracy of those judgments.

Acoustic Stimulation↗