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At least 19 recordsLinked to original sources
PubMed1976

Age differences in personality structure: a cluster analytic approach.

A cluster analytic approach was used to determine possible age differences in the structure of personality as measured by the Cattell Sixteen Personality Factor Questionnaire. Subjects were 969 adult male volunteers, originally divided into three groups: 25 to 34, 35 to 54, and 55 to 82. Two familiar dimensions of personality, Anxiety-Adjustment and Introversion-Extraversion, were found to be cross sectionally stable. A third cluster dimension, interpreted as openness to experience, showed age-related differences. Young subjects showed openness to feelings; middle-aged subjects showed openness to ideas; and old subjects showed a balanced openness to both feelings and ideas. Repartitioning of the sample into two groups (ages 25 to 43 and 44 to 82), and three groups (25 to 39, 40 to 47, and 48 to 82) confirmed these age differences in the third cluster. The interpretation of the third cluster is discussed in terms of Jung's concepts of psychological functions.

Age Factors↗
PubMed1990

Current analytical approaches to measuring blood analytes.

In recent years, laboratory testing in the critical-care setting has increased, a trend due, in part, to the evolution of electrochemical sensors. Various innovations have extended sensor lifetimes, reduced sensor maintenance, and led to the development of single-use and unit-use disposable sensors. These sensor technologies allow the accurate and precise determination, either at or near the bedside, of several analytes including pO2, pCO2, pH, Na, K, Cl, ionized calcium, hematocrit, total hemoglobin, and glucose. Use of these new systems, however, has raised new issues regarding sensor calibration and sample handling and collection. The number of direct-reading analyzers for electrolyte determinations has also increased dramatically. Issues regarding calibration of ion-selective electrodes (ISEs) for Na/K have also been raised after demonstrations of between-instrument variation. Recently, collaborative efforts between eight ISE instrument manufacturers and the National Institute of Standards and Technology resulted in the development of a Standard Reference Material, SRM 956, for the purpose of standardizing direct-reading Na/K ISEs to the flame photometer. Other widely used technologies that provide noninvasive, continuous monitoring include pulse oximetry and transcutaneous gas electrodes. These trends are expected to continue and to produce a new generation of electrochemical and optical sensors.

Autoanalysis↗
PubMed1988

Electrodiagnosis of diabetic peripheral polyneuropathy. A multivariate analytic approach.

Traditional univariate comparisons of nerve conduction data against standard norms may produce conflicting estimates of the presence or absence of a diabetic neuropathy, depending upon the data obtained and the specific nerves sampled. Alternatively, a multivariate analytic approach, using discriminant functions, provides a useful single measure of the degree of neuropathy determined as a weighted combination of the available data. The weights are derived from the linear discriminant function, which maximizes statistical separation of diabetic and nondiabetic subject groups. In this study, 12 electrophysiologic attributes are used to generate a single discriminant function that clearly separates diabetic from nondiabetic subjects and is interpretable as a neuropathic index. Each individual's index of diabetic neuropathy (I) can be quantified as follows: (Formula: see text) where Ai is the original electrophysiologic attribute (i = 12), ai is the coefficient for each attribute that defines the discriminant function and C is a constant specific for that function. For the first time, the degree of diabetic neuropathy can thus be quantified for purposes of comparison and correlation with other quantifiable clinical/somatic measures of diabetes. The index allows for a higher percentage of type II diabetic patients to be classified as neuropathic than previously described and enables determination of degree of neuropathy is affected individuals by an interpolative method.

Analysis of Variance↗
PubMed1988

Determination of polychlorinated biphenyls in human foodstuffs and tissues: suggestions for a selective congener analytical approach.

Based on a literature review of the occurrence of polychlorinated biphenyl (PCB) congeners in commercial formulations, environmental and biological samples and human tissues, and a consideration of the relative toxicity and persistence of the congeners, suggestions are made as to the most relevant components to be quantified by a selective congener analytical approach to human foodstuffs and tissues. These criteria suggest congener numbers 28, 74, 77, 99, 105, 118, 126, 128, 138, 153, 156, 169, 170, 179 and 180 will give a measure of greater than 70% of the total PCB tissue burden in a sample and be of greatest toxicological significance. Additionally, congeners 8, 37, 44, 49, 52, 60, 66, 70, 82, 87, 101, 114, 158, 166, 183, 187 and 189 are considered because of their reported occurrence or toxicity.

Adipose Tissue↗
PubMed1988

Validating the components of a taxonomic system for rapists: a path analytic approach.

This study was part of a series designed to validate a classification system for rapists developed at the Massachusetts Treatment Center. This system (MTC:R2) determines subtypes according to three major dimensions: the meaning of the aggression in the rapist's offenses (expressive versus instrumental), the meaning of the sexual behavior (compensatory, exploitative, displaced anger, or sadistic), and the degree of general lifestyle impulsivity (low or high). A total of 201 rapists were subtyped using this system. A path analytic approach was used to relate family, juvenile, and adult histories to the main decisions of subtype assignment. The classification of an offender on each of the three dimensions was informed by a developmental perspective. Results provided support for the use of the discriminators used and highlighted the deficiencies in our current knowledge regarding developmental precursors. These results were integrated with the findings from other studies using MTC:R2 and suggestions for revisions to the current classification system were discussed.

Aggression↗
PubMed1990

New in vitro analytical approaches for clinical chemistry measurements in critical care.

The effective management of patients in intensive care units, operating rooms, and emergency rooms requires frequent measurement of a select group of analytes, preferably at or near the patient's bedside. Tests recognized as being essential for such management include blood gases and related variables (pH, pO2, pCO2, HCO3-, hematocrit/hemoglobin, O2 saturation), electrolytes (Na+, K+, Ca2+, Cl-), and in some cases, certain metabolites (glucose, lactate, urea, creatinine). This report describes the measurement principles, practical instrumental designs, analytical performance, and limitations of several newer electrochemical sensor-based approaches useful for in vitro determination of these species in undiluted whole-blood samples. Considerable attention is given to the most recent advances in ion-selective electrode technology as they relate to blood gas and electrolyte determinations. Similar attention is given to modern enzyme-electrode techniques, which are useful for direct measurements of metabolites in whole blood. The challenges of integrating these new analytical methods into convenient, multi-analyte, user-friendly, bedside or stat-lab instruments are also discussed.

Autoanalysis↗
PubMed1975

Analytical approach for depth dose calculations (60Co beams with fixed source-target distance).

A method is described to calculate depth dose distribution to a principal plane using analytical formulas for 60Co teletherapy units and constant source-to-target distance. The formulas were derived from experimental measurements taking into consideration the obliquity of the beam. For the purposes of dose calculation the beam was divided into primary and scattered components. A computer program incorporating the formulas was developed for an IBM 360/67 computer. Dose distributions computed and obtained from experimental measurements were in good agreement. The computer program is now in use for treatment planning, including rotational techniques.

Cobalt Radioisotopes↗
PubMed1990

Analytical approaches to the study of monoclonal antibody stability.

The stability of two purified monoclonal antibodies, MN12 and WT31, was investigated. The monoclonal antibodies were incubated for 32 days at different pH values (ranging from 3.0 to 10.0) at 4 and 37 degrees C. Various analytical methods were used to assess changes in physicochemical properties of the proteins. The monoclonal antibodies were more susceptible to degradation at 37 degrees C than at 4 degrees C. At low pH irreversible precipitation occurred. Decomposition of the proteins was enhanced at increasing pH values in the alkaline range. This was concluded from mouse IgG-specific and antigen-specific enzyme-linked immunosorbent assays, flow cytometry, analytical gel permeation chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, isoelectric focusing, and immunoblotting. No substantial change in the apparent affinity constant of MN12 was observed, as determined by an affinity enzyme-linked immunosorbent assay. Fluorescence spectra, fluorescence polarization values, and fluorescence quenching parameters of MN12 and WT31 were not substantially affected, indicating that no major irreversible conformational changes had occurred. It was concluded that each of the techniques used has only limited value for stability assessment of monoclonal antibodies and, hence, that the application of several analytical techniques is essential to gain insight into monoclonal antibody stability.

Animals↗
PubMed1988

The process of gas exchange in systemic circulation in a hyperbaric environment: an analytical approach.

A mathematical model is proposed to deal with the simultaneous transport of oxygen (O2) and carbon dioxide (CO2) in systemic capillaries and the surrounding tissue in a hyperbaric environment. The transport in the capillary region depends on molecular diffusion (radial as well as axial), the convective effect of the blood, and the saturation of haemoglobin with O2 and CO2. The corresponding equation in the tissue region describes the transport of the species due to radial and axial diffusion in the tissue and consumption of O2 in the metabolic process. The production of CO2 inside the tissue is incorporated through the respiratory quotient. The saturation of blood with O2 and CO2 have been approximated by linear functions to simulate the conditions of the hyperbaric environment. The resulting system of governing equations with the physiologically relevant boundary conditions is solved analytically. The concentration of O2 is shown to decrease from the core of the capillary to the tissue periphery, whereas the concentration of CO2 increases. It is shown that very little of the CO2 is transported radially. The location of the vulnerable point from the point of view of CO2 accumulation is found to be the corner (x = R2, z = L) situated at the periphery of the tissue near the venous end of the capillary. The accumulation of O2 and CO2 in the tissue is discussed in terms of various dimensionless parameters. It is found that the accumulation of CO2 increases whereas that of O2 decreases in the hyperbaric environment. Finally, it is surmised that one of the major causes of discomfort among divers could be excessive accumulation of CO2 in the tissue.

Blood Circulation↗
PubMedDate not supplied

An analytical approach to quantify uniformity artifacts for circular and noncircular detector motion in single photon emission computed tomography imaging.

Uniformity artifacts in rotating gamma camera tomography will result if there are errors in the correction factors which are routinely calculated from a static uniformity flood image. The accuracy of the correction factors is a function of the statistics in the collected flood image. Since the factors are applied to each projection view, an error in a correction factor will propagate as a projection error at the same pixel location for each view. For circular detector motion, the error in each projection is reconstructed as a ring whose maximum amplitude varies approximately inversely proportional to the square root of the distance of the projection error from the center of rotation. For noncircular detector motion the artifacts are not rings but are more complicated geometric curves. Simulations show that statistical fluctuations in the reconstructed image will mask the uniformity artifacts provided the correction flood satisfies minimum count requirements. An analytical expression is derived for the percent root-mean-square (% rms) error in the reconstruction and is compared with the percent relative amplitude error (% RAE) of the reconstructed artifacts in order to obtain expressions for uniformity flood counting statistics. For an elliptical source distribution with total counts equal to CT, the uniformity statistics required to reconstruct elliptical disks is inversely proportional to the square root of the area: U greater than or equal to KCT/area 1/2. The constant K depends on the filter function and type of detector motion.

Biophysical Phenomena↗
PubMed1992

Life-style and substance use among male African-American urban adolescents: a cluster analytic approach.

Cluster analyzed four variables: school attendance, employment, church attendance, and delinquency, to develop life-style profiles. Data from 218 African-American urban adolescents were used in the study. Five meaningful clusters were retained and subjected to criterion validity analyses using measures of spirituality, participation in a voluntary organization, self-esteem, and friend's substance use. The five clusters were then compared on cigarette, alcohol, marijuana, and hard drug use. The results suggest that a life-style that includes an adaptive compensatory behavior component may be more adaptive than a life-style that does not include compensatory behavior. For example, youths who left high school before graduation but were involved in church reported less alcohol and substance use than youths who left school and were not involved in any meaningful instrumental activity. Implications for intervention and future research on high-risk behaviors are discussed.

Adolescent↗
PubMed1990

Heart rate variability in diabetic patients during orthostatic load--a spectral analytic approach.

Spectral analysis of heart rate variability (HRV) was used to assess the autonomic nervous control of cardiac function during orthostatic load in insulin-dependent diabetic patients and healthy subjects. The diabetic patients were divided into three groups: diabetics without neuropathy (group 1), diabetics with peripheral neuropathy (group 2), and diabetics with peripheral and autonomic neuropathy (group 3). Resting mid-frequency (MF, 0.05-0.15 Hz) and respiration-related (RF, power around respiration rate) HRV were significantly lower in group 2 and 3 diabetics than in controls, indicating a reduced parasympathetic nervous system influence on the heart. Standing MF and RF spectral power data were significantly lower in all diabetic groups than in controls, suggesting marked alterations in the autonomic cardiovascular control during a mild physical load not only in symptomatic diabetics but also in patients with no signs and symptoms of neuropathy. The difference between supine and standing MF power, an estimate of beta-adrenergic influence on the heart, was significantly lower in all diabetic subject groups studied than in controls. This suggests a reduced sympathetic nervous system influence on the heart in diabetic patients. Our data suggest that computerized spectral analysis of HRV during orthostatic load seems to be a very sensitive method of evaluating of the autonomic nervous systems influence on the heart in patients suffering from diabetes mellitus.

Adult↗
PubMedDate not supplied

Analytical approach to mathematical modelling of the isometric contraction of the hypertrophied myocardium.

It is attempted on the basis of the Hill two-element model to simulate mathematically the rising phase of the isometric mechanogram in the pressure-hypertrophied rat myocardium (Goldblatt II). The evaluation is based on the experimentally determined force-velocity relation as well as on the characteristic of the series-elastic stiffness. The changes in the isometric mechanogram of the hypertrophied heart muscle observed in the experiment can be mathematically predicted solely by means of the alterations in the force-velocity relationships induced by the hypertrophy, whereby the characteristic of the series-elastic stiffness is considered to be unchanged.

Cardiomegaly↗
PubMed1986

The merging of participatory and analytical approaches to evaluation: implications for nurses in primary health care programs.

This paper addresses the need to make evaluation part of the nurse's expanded role within the Primary Health Care system. In a social policy and decision-making context, the nurse is an intermediary between political authorities and community groups. This requires diverse, but complementary, evaluation skills. The author proposes a dual method of evaluation for community health programs. The approach incorporates an objective-stance Logical Framework Analysis Model, to meet agencies' needs for program effectiveness and impact data, and a Participatory Evaluation approach, to recognize the ability of communities to judge whether health services are responsive to their needs. The nature and application of both methods within an International Primary Health Care context are explored. The paper concludes that access to a wide spectrum of evaluation data places the nursing profession in a challenging position to influence policy decisions related to health services.

Community Health Nursing↗
PubMed1990

Toward an identification of mechanical parameters initiating periosteal remodeling: a combined experimental and analytic approach.

The ability of bone to adapt to its mechanical environment is well recognized, although the specific mechanical parameters initiating or maintaining the adaptive responses have yet to be identified. Recently introduced mathematical models offer the potential to aid in the identification of such parameters, although these models have not been well validated experimentally or clinically. We formulated a complementary experimental/analytic approach, using an animal model with a well-controlled mechanical environment combined with finite element modeling (FEM). We selected the functionally isolated turkey ulna, since the loading could be completely characterized and the periosteal adaptive responses subsequently monitored and quantified after four and eight weeks of loading. Known loads input into a three-dimensional, linearly elastic FEM of the ulna then permitted full-field mechanical characterization of the ulna. The FEM was validated against a normal strain-gaged turkey ulna, loaded in vivo in an identical fashion to the experimental ulnae. Twenty-four candidate mechanical parameters were then compared to the quantified adaptive responses, using statistical techniques. The data supported strain energy density, longitudinal shear stress, and tensile principal stress/strain as the mechanical parameters most likely related to the initiation of the remodeling response. Model predictions can now suggest new experiments, against which the predictions can be supported or falsified.

Adaptation, Physiological↗
PubMed1989

Seasonal changes in mood and behavior: a cluster analytic approach.

We report on the cluster analysis of 416 subjects from Montgomery County, Maryland, USA, who responded to lay interviewers using a telephone version of the Seasonal Pattern Assessment Questionnaire (SPAQ). Eight clusters are described, the smallest of which is consistent with a pattern comparable to that seen in patients with winter seasonal affective disorder (SAD). A larger group of individuals seems to demonstrate patterns equivalent to that of subsyndromal winter SAD patients. Furthermore, it was apparent that a large percentage of the study group seems to be affected to some degree by the characteristics of the seasons. It was observed, perhaps for the first time, that feeling worse when there is a high pollen count appears to be associated with the symptom pattern seen in winter SAD patients. There is also evidence for the existence of a group of summer subsyndromal SAD subjects.

Adult↗
PubMed1991

Seasonal variations in mood and behavior in the general population: a factor-analytic approach.

In a mailed survey conducted at four centers--Nashua, NH; New York, NY; Washington, DC; and Sarasota, FL--1,671 respondents provided information on monthly variations in 10 behavioral categories representing extremes in the areas of mood, socializing, appetite, weight gain/loss, and sleep length. A 10-factor solution revealed the following factors: (1) a winter weight gain factor; (2) a winter depression factor; (3) a winter hypersomnia factor; (4) a summer weight gain factor; (5) a summer hypersomnia factor; (6) a summer depression factor; (7) a winter socializing factor; (8) a winter weight loss factor; (9) a fall depression factor; and (10) a possibly mixed factor. Factors consistent with winter seasonal affective disorder were positively correlated with latitude, while those consistent with summer seasonal affective disorder were negatively correlated with latitude.

Affect↗