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PubMed2005

[Emergency nurse-patient interaction behavior].

PURPOSE: The main purpose of this study was to explore nurse-patient interaction behaviors and patient satisfaction with the interaction in the emergency department. METHOD: This study used video technology to record complete conversations between the nurse and patient, thus obtaining the interactions naturally occurring in a clinical setting. The participants were 28 nurses and 63 patients in the emergency department at one university hospital located in Seoul. The data was collected from November, 2002 to April, 2003. The video recordings were observed for 4 hours for each case and coded using an adapted version of Roter's Interaction Analysis System (RIAS), which yields frequencies of thirty-six types of interaction behaviors. RESULT: The information exchange related to therapeutic items including medications, simple orientation, and situational positive talk were characterized in the nurses' interaction behaviors. Giving information about one's own condition, questions about therapeutic regimen, and showing worry were characterized in patient interaction behaviors. The patients' satisfaction with the interaction was 37.75.9 (range 9-45). CONCLUSION: The emergency nurse-patient interaction behavior was task-related. The results suggest that identification of effective interaction behavior in the Emergency department and an interaction skill training program could increase patient satisfaction.

Adult↗

PubMed2002

Towards the prediction of complete protein--protein interaction networks.

We present a statistical method for the prediction of protein--protein interactions within an organism. This approach is based on the treatment of proteins as collections of conserved domains, where each domain is responsible for a specific interaction with another domain. By characterizing the frequency with which specific domain--domain interactions occur within known interactions, our model can assign a probability to an arbitrary interaction between any two proteins with defined domains. Domain interaction data is complemented with information on the topology of a network and is incorporated into the model by assigning greater probabilities to networks displaying more biologically realistic topologies. We use Markov chain Monte Carlo techniques for the prediction of posterior probabilities of interaction between a set of proteins; allowing its application to large data sets. In this work we attempt to predict interactions in a set of 40 human proteins, known to form a connected network, and discuss methods for future improvement.

Markov Chains↗

PubMed2004

The interfacial dilational properties of hydrophobically modified associating polyacrylamide studied by the interfacial tension relaxation method at an oil-water interface.

The interfacial dilational viscoelastic properties of hydrophobically associating block copolymer composed of acrylamide (AM) and a low amount of 2-phenoxylethyl acrylate (POEA) (<1.0 mol%) at the octane-water interfaces were studied by means of the interfacial tension relaxation method. The dependencies of interfacial dilational elasticity and viscous component on the dilational frequency were investigated. The interaction of hydrophobically associating block copolymer [P(AM/POEA)] with sodium dodecyl sulfate (SDS) has been explored. The results show that at lower frequency, the dilational elasticity for different concentration copolymer is close to zero; at higher frequency, the dilational elasticity shows no change with increased frequency; At moderate frequency (10(-3)-1 Hz), the dilational elasticity decreased with a decrease in the dilational frequency. The results show that the hydrophobic groups of [P(AM/POEA)] chains can be associated by inter- or intrachain liaisons in water solution. The dilational viscous component for P(AM/POEA) comes forth a different maximum value at different frequencies when the polymer concentration is different. It is generally believed that the dilational viscous component reflects the summation of the various microscopic relaxation processes at and near the interface and different relaxation processes have different characteristic frequencies. The spectrum of dilational viscous component may appear more than once maximum values at different frequencies. The influence of SDS on the limiting dilational elasticity and viscous component for polymer solution was elucidated. For 5000 ppm polymer solution, the limiting dilational elasticity decreased with an increase in SDS concentration. The dilational viscous component passed through a maximum value with a rise in the dilational frequency, which appeared at different frequency when SDS concentration is different; and the higher is the concentration, the lower is the dilational frequency. It can be explained that macromolecules may be substituted by SDS molecules in the interface and the interaction of molecules decrease, which makes the limiting dilational elasticity decrease. For 200 ppm polymer solution, the limiting dilational elasticity increased firstly and then decreased with SDS concentration increasing. This may be explained that the interfacial polymer concentration is so low that SDS molecules absorbed in the interface dominate dilational properties of the interfacial film even at very low SDS concentration. However, SDS molecules can gradually substitute the polymer molecules in the interface with a rise in SDS concentration, which results in the decrease in the limiting dilational elasticity.

Journal Article↗

PubMedDate not supplied

An interactive activation approach to object processing: effects of structural similarity, name frequency, and task in normality and pathology.

We present a computational model of the processes involved in retrieving stored semantic and name information from objects, using a simple interactive activation and competition architecture. We simulate evidence showing a cross-over in normal reaction times to make semantic classification and identification responses to objects from categories with either structurally similar or structurally dissimilar exemplars, and that identification times to objects from these two different classes correlate differentially with measures of the structural similarity of objects within the category and the frequency of the object's name. Structural similarity exerts a negative effect on object decision as well as naming, though this effect is larger on naming. Also, on naming, structural similarity interacts with the effects of name frequency, captured in the model by varying the weight on connections from semantic to name units; frequency effects are larger with structurally dissimilar items. In addition, (1) the range of potential errors for objects from these two classes, when responses are elicited before activation reached a stable state, differ--a wider range of errors occur to objects from categories with structurally similar exemplars; and (2) simulated lesions to different locations within the model produce selective impairments to identification but not to semantic classification responses to objects from categories with structurally similar exemplars. We discuss the results in relation to data on visual object processing in both normality and pathology.

Anomia↗

PubMed1985

Scatterer-induced frequency variations in reflected acoustic pulses: implications for tissue characterization.

A Hilbert transform approach to the detection of the instantaneous center frequency of reflected ultrasonic pulses was performed for simulated reflected ultrasonic pulses, and digitized ultrasonic waveforms from tissue phantoms. Considerable center frequency modulation was observed for both simulated and recorded ultrasonic waveforms. This phenomenon of frequency modulation can be explained with the aid of a phasor model, in which variations in instantaneous frequency results from the interaction of a multitude of overlapping ultrasonic pulses arising from different scattering centers in tissue. The observed frequency modulation of ultrasonic signals has important implications for tissue characterization techniques, including the measurement of attenuation by the determination of the shift in ultrasonic center frequency.

Mathematics↗

PubMed1985

Increasing handicapped preschoolers' peer social interactions: cross-setting and component analysis.

The purposes of our study were: (a) to train a set of observationally determined social behaviors via peer initiation; (b) to determine if effects generalized across classroom settings and to directly intervene if generalization did not occur; and (c) to analyze components of the peer-initiation intervention. After baseline, nonhandicapped preschool children (confederates) were taught to direct social initiations to the three handicapped preschool-aged students. Teachers prompted the confederates to engage the students in social interaction when necessary and rewarded the confederates with tokens. Confederates' initiations to the students resulted in increased frequencies of positive social interaction. There was no generalization to other classroom settings, and the intervention was subsequently implemented in a second and third classroom. Next, the confederates' token reinforcement system was withdrawn, with no apparent deleterious effects on the confederates' or students' social interactions. When teachers substantially reduced their prompts to the confederates, students' social interactions decreased. Finally, reinstatement of teacher prompts resulted in increases in the confederates' social initiations and, consequently, the positive social interactions of the students.

Behavior Therapy↗

PubMed1997

Phase correlation among rhythms present at different frequencies: spectral methods, application to microelectrode recordings from visual cortex and functional implications.

In classical EEG analysis rhythms with different frequencies occurring at separable regions and states of the brain are analysed. Rhythms in different frequency bands have often been assumed to be independent and their occurrence was interpreted as a sign of different functional operations. Independence has scarcely been proved because of conceptual and computational difficulties. It is, on the other hand, probable that different rhythmic brain processes are coupled because of the broad recurrent connectivity among brain structures. We, therefore, set out to find interactions among rhythmic signals at different frequencies. We were particularly interested in interactions between lower frequency bands and gamma-activities (30-90 Hz), because the latter have been analysed in our laboratory in great detail and had properties suggesting their involvement in perceptual feature linking. Fast oscillations occurred synchronized in a stimulus-specific way in the visual cortex of cat and monkey. Their presence was often accompanied by lower frequency components at considerable power. Such multiple spectral peaks are known from many cortical and subcortical structures. Despite their well known occurrence, coupling among different frequencies has not been established, apart from harmonic components. For the present investigation we extended existing analytical tools to detect non-linear correlations among signal pairs at any frequency (including incommensurate ones). These methods were applied to multiple microelectrode recordings from visual cortical areas 17 and 18 of anesthetized cats and V1 of awake monkeys. In particular, we assessed non-linear correlations by means of higher order spectral analysis of multi-unit spike activities (MUA) and local slow wave field potentials (LFP, 1-120 Hz) recorded with microelectrodes. Non-linear correlations among signal components at different frequencies were investigated in the following steps. First, the frequency content of short (approximately 250 ms) sliding window signal epochs was analyzed for simultaneously occurring rhythms of significant power at different frequencies. This was done by a newly developed method derived from the trispectrum using separate averaging of the products of short-epoch power spectra for any possible combination of frequency pairs. Second, non-linear (quadratic) phase coupling between different frequencies was assessed by the methods of bispectrum and bicoherence. We found phase correlations at different frequencies in the visual cortex of the cat and monkey. These couplings were significant in about 60% of the investigated MUA and LFP recordings, including several cases of coupling among incommensurate (i.e. non-harmonic) frequencies. Significant phase correlations were present: (1) within the gamma-frequency range; (2) between gamma- and low frequency ranges (1-30 Hz, including alpha- and beta-rhythms); and (3) within the low frequency range. Phase correlations depended, in most cases, on specific visual stimulation. We discuss the possible functional significance of phase correlations among high and low frequencies by including proposals from previous work about potential roles of single-frequency rhythms of the EEG. Our suggestions include: (1) visual feature linking across different temporal and spatial scales provided by coherent oscillations at high and low frequencies; (2) linking of visual cortical representations (high frequencies) to subcortical centers (low frequencies) like the thalamus and hippocampus; and (3) temporal segmentation of the sustained stream of incoming visual information into separate frames at different temporal resolutions in order to prevent perceptual smearing due to shifting retinal images. These proposals are, at present, merely speculative. However, they can, in principle, be proved by microelectrode recordings from trained behaving animals.

Animals↗

PubMed2003

Restricted clonal expression of IL-2 by naive T cells reflects differential dynamic interactions with dendritic cells.

Limited frequencies of T cells express IL-2 in primary antigenic responses, despite activation marker expression and proliferation by most clonal members. To define the basis for restricted IL-2 expression, a videomicroscopic system and IL-2 reporter transgenic model were used to characterize dendritic cell (DC)-T cell interactions. T cells destined to produce IL-2 required prolonged interactions with DCs, whereas most T cells established only transient interactions with DCs and were activated, but did not express IL-2. Extended conjugation of T cells with DCs was not always sufficient to initiate IL-2 expression. Thus, there is intrinsic variability in clonal T cell populations that restricts IL-2 commitment, and prolonged engagement with mature DCs is necessary, but not sufficient, for IL-2 gene transcription.

Animals↗

PubMed1983

An investigation into the representations involved in visual masking.

Two experiments are reported in which the nature of the representations involved in visual masking with spatially overlapping stimuli is investigated. Recent work is described which was consistent with the proposal of Breitmeyer and Ganz (1976) that masking phenomena can be understood in terms of interactions between spatial-frequency-tuned channels. In the first experiment targets which had been filtered to contain only high or low spatial frequencies were masked by high or low frequency masks. The results were more consistent with a model of masking in which higher-order representations, possibly derived from spatial-frequency information, were involved. A second experiment was carried out to test this conjecture which involved investigating the interaction between the effects of learning and the type of information used in target identification. The results provided further support for the model.

Discrimination Learning↗

PubMed2005

The evolution of resource specialization through frequency-dependent and frequency-independent mechanisms.

Levins's fitness set approach has shaped the intuition of many evolutionary ecologists about resource specialization: if the set of possible phenotypes is convex, a generalist is favored, while either of the two specialists is predicted for concave phenotype sets. An important aspect of Levins's approach is that it explicitly excludes frequency-dependent selection. Frequency dependence emerged in a series of models that studied the degree of character displacement of two consumers coexisting on two resources. Surprisingly, the evolutionary dynamics of a single consumer type under frequency dependence has not been studied in detail. We analyze a model of one evolving consumer feeding on two resources and show that, depending on the trait considered to be subject to evolutionary change, selection is either frequency independent or frequency dependent. This difference is explained by the effects different foraging traits have on the consumer-resource interactions. If selection is frequency dependent, then the population can become dimorphic through evolutionary branching at the trait value of the generalist. Those traits with frequency-independent selection, however, do indeed follow the predictions based on Levins's fitness set approach. This dichotomy in the evolutionary dynamics of traits involved in the same foraging process was not previously recognized.

Conservation of Natural Resources↗

PubMed2002

Effects of the near-dipole-dipole interaction on gap solitons in resonantly absorbing gratings.

Gap solitons can exist in a periodic refractive-index grating modified by periodic layers of near-resonant two-level systems. In this work, we include the effect of the density-dependent near-dipole-dipole (NDD) interaction in order to generalize this model. For certain values of the grating parameters, we find that the NDD interaction significantly modifies the frequency bands in which gap solitons can exist. The difference between the model with and without the NDD interaction is discussed. The stability of gap solitons is studied numerically.

Journal Article↗

PubMed1996

Interaction of isoflurane and nitrous oxide combinations similar for median electroencephalographic frequency and clinical anesthesia.

BACKGROUND: The volatile anesthetic sparing effect of nitrous oxide in clinical studies is less than might be expected from the additivity of minimum alveolar concentration values. Other studies identify nonadditive interactions between isoflurane and nitrous oxide. The aim of this study was to quantify the interaction of isoflurane and nitrous oxide at a constant median electroencephalographic frequency. METHODS: Twenty-five patients were studied during laparotomies. Nitrous oxide was randomly administered in concentrations of 0, 20, 40, 60, and 75 vol%, to ten patients for each nitrous oxide concentration. Isoflurane vaporizer settings were chosen so that the median electroencephalographic frequency was held between 2 and 3 Hz. The relationship between nitrous oxide concentrations and required isoflurane concentrations was examined with the method of isoboles. RESULTS: Nitrous oxide linearly decreased the isoflurane requirement. Addition of every 10 vol% of nitrous oxide decreases the isoflurane requirement by approximately 0.04 vol%. The total anesthetic requirement of isoflurane and nitrous oxide, expressed in terms of previously reported minimum alveolar concentration values, increased significantly with increasing nitrous oxide concentrations. CONCLUSIONS: The interaction of isoflurane and nitrous oxide in the dose range 0-75 vol% on median electroencephalographic frequency is compatible with additivity. The potency of nitrous oxide as a substitute for isoflurane is less than on a minimum alveolar concentration basis. Maintaining median electroencephalographic frequency more appropriately reflects the clinical usage of isoflurane and nitrous oxide than does maintaining minimum alveolar concentration.

Adult↗

PubMed2005

Immunoassay of prostate-specific antigen (PSA) using resonant frequency shift of piezoelectric nanomechanical microcantilever.

We designed and fabricated the nanomechanical Pb(Zr0.52Ti0.48)O3 (PZT) cantilever; we demonstrated a novel electrical measurement, under a controlled ambient temperature and humidity, for label-free detection of a prostate-specific antigen (PSA); and we achieved a detection sensitivity as low as 10 pg/ml. For the fabrication of our nanomechanical PZT cantilevers, we used composite layers of Ta/Pt/PZT/Pt/SiO2 on a SiN(x) supporting layer for electrical self-sensing without external oscillators. This method allows PSA proteins to be detected via a simple electrical measurement of the resonant frequency change generated by the molecular interaction of the antigen (Ag) and the antibody (Ab). The resonant frequency shifted due to the specific binding of the PSA Ag to its Ab which is immobilized via calixcrown self-assembled monolayers on an Au surface deposited on a nanomechanical PZT cantilever. We determined the resonant frequency shift as the value of -172 Hz and -273 Hz, when the concentration of PSA Ag was 1 ng/ml, with the cantilever dimensions of 100 microm x 300 microm and 50 microm x 150 microm, respectively. Theoretical and experimental analysis suggests that the minimum detectable sensitivity for a resonant frequency shift due to a PSA Ag-Ab interaction depends on the dimensions of the nanomechanical PZT cantilever. These results also demonstrate that the experimentally measured resonant frequency shift is larger than that calculated theoretically due to the compressive stress of the PSA Ag-Ab interaction.

Biomarkers, Tumor↗

PubMed2000

Structure, energetics, vibrational frequencies and charge transfer of base pairs, nucleoside pairs, nucleotide pairs and B-DNA pairs of trinucleotides: ab initio HF/MINI-1 and empirical force field study.

Geometries, interaction energies and vibrational frequencies of base pairs, nucleoside pairs and nucleotide pairs were studied by ab initio Hartree-Fock (HF) method using MINI-1 basis set and empirical Cornell et al. force field (AMBER 4.1). A good agreement was found between HF/MINI-1 and AMBER results. In addition, both methods provide reasonable agreement with available high-level ab initio data. Finally, AMBER potential was used to determine the structure, energetics and vibrational frequencies of B-DNA pairs of trinucleotides. Stabilization energies of clusters are lowered when passing from base pairs to nucleoside pairs, nucleotide pairs and to pairs of trinucleotides. The lowest vibrations of base pairs and nucleoside pairs correspond to intermolecular motions of bases, specifically to buckle and propeller motions. In the case of pairs of larger subunits the lowest vibrations are of intramolecular nature (rotation around glycosidic bond, sugar and phosphate vibration). The spectra of these clusters became more complicated and quasi-degenerate. Intermolecular charge transfer between bases in H-bonded and stacked pairs is negligible, while a significant intramolecular charge transfer was observed.

Base Pairing↗

PubMed1989

Hemispheric asymmetry in the processing of high and low spatial frequencies: a facial recognition task.

The research investigated the relationship between spatial frequency and visual field in a facial recognition task. Faces of neutral affect (Ekman, 1979) were tachistoscopically presented to the right or left visual field. The faces were presented alone, or masked with square wave gratings of 1, 24, or 48 cycles/degree, for a duration of 10 msec. Accuracy in recognizing each target face from a group of five served as the dependent measure. Subjects were 15 males and 15 females. ANOVA results included a frequency x visual field interaction effect (p less than .001). As was hypothesized, LVF errors were highest in the absence of low spatial frequencies, while RVF errors were highest when a higher range of spatial frequencies was removed. These results confirm that the hemispheres show a differential efficiency in processing high and low spatial frequency information in faces. They also offer empirical evidence to support the clinical findings that both hemispheres contribute to facial recognition.

Adult↗

PubMed1992

Neighborhood frequency effects and letter visibility in visual word recognition.

Two experiments are described that measured lexical decision latencies and errors to five-letter French words with a single higher frequency orthographic neighbor and control words with no higher frequency neighbors. The higher frequency neighbor differed from the stimulus word by either the second letter (e.g., ASTRE-AUTRE) or the fourth letter (CHOPE-CHOSE). Neighborhood frequency effects were found to interact with this factor, and significant interference was observed only to CHOPE-type words. The effects of neighborhood frequency were also found to interact with the position of initial fixation in the stimulus word (either the second letter or the fourth letter). Interference was greatly reduced when the initial fixation was on the critical disambiguating letter (i.e., the letter P in CHOPE). Moreover, word recognition was improved when subjects initially fixated the second letter relative to when they initially fixated the fourth letter of a five-letter word, but this second-letter advantage practically disappeared when the stimulus differed from a more frequent word by its fourth letter. The results are interpreted in terms of the interaction between visual and lexical factors in visual work recognition.

Adult↗

PubMedDate not supplied

Greening healthcare: practicing as if the natural environment really mattered.

OBJECTIVE: The natural world's role in human well-being is an essential, yet often forgotten, aspect of healthcare. Of particular importance are the benefits one can derive through interaction with natural environments. While health is an obvious goal of allopathic medicine, many healthcare settings are neither nurturing nor healing. Reincorporating the natural world into the design of settings in which medicine is practiced is one way to complement conventional healing modalities and move healthcare toward being more "green." This article discusses the breadth of existing knowledge available on the positive aspects of interaction with nature and provides a comprehensive theoretical perspective for future research. DATA SOURCES: Computerized searches were conducted using MEDLINE, PsycINFO, the Social and Scientific Science Indices, Dissertation Abstracts, Lexus-Nexus, the University of Michigan library, and the Internet. Searches were conducted from June 2001 through March 2002. STUDY SELECTION: Keywords used included health, well-being stress, attention, nature, garden, landscape, restorative, and healing. The literature, published between 1960 and 2001, came from various disciplines, including medicine, public health, nursing psychology, natural resources, history, and landscape architecture. Four components of well-being were used as a framework for literature selection: physical psychological-emotional social, and spiritual. DATA EXTRACTION: Articles were qualitatively reviewed to extract theories, hypotheses, and experimental evidence. DATA SYNTHESIS: Interaction with nature positively affects multiple dimensions of human health. Physiological effects of stress on the autonomic nervous system are lessened. Psychologically, deficits in attention can be restored or minimized, and people report feeling greater satisfaction with a variety of aspects of life. The presence of the natural world promotes social health by encouraging positive social interaction and lessening the frequency of aggressive behavior. Spiritual well-being is enhanced through the experience of greater interconnectedness, which occurs when interacting with the natural world. CONCLUSIONS: The literature reviewed provides evidence to support the intuitive belief that interaction with the natural world is a vital part of biopsychosocial-spiritual well-being. Incorporating the natural world into healthcare could provide health benefits and improve the design of healthcare facilities. Applied more broadly to society, this knowledge may change the way we approach public health, guard and manage natural resources, and design environments for human use.

Attitude to Health↗

PubMed2004

Clinical application of sperm-oocyte interaction tests in in vitro fertilization--embryo transfer and intracytoplasmic sperm injection programs.

OBJECTIVE: To review the clinical value of sperm-oocyte interaction tests for the diagnosis and management of infertility by standard IVF or intracytoplasmic sperm injection (ICSI). DESIGN: Review of recent publications on relationships among sperm-oocyte interaction tests, sperm characteristics, and results of IVF and determination of frequency of defective sperm-oocyte interaction in infertile men. MAIN OUTCOME MEASURE(S): Fertilization rates with IVF, sperm characteristics, sperm-zona pellucida (ZP) binding, ZP-induced acrosome reaction (AR), and sperm-ZP penetration. RESULT(S): Sperm defects associated with low sperm-ZP binding or impaired ZP-induced AR and sperm-ZP penetration are the major causes of failure of fertilization when all or most oocytes from a couple do not fertilize in standard IVF. There is a high frequency of defective sperm-ZP interaction in men with oligozoospermia (<20 x 10(6)/mL) and severe teratozoospermia (strict normal sperm morphology < or =5%). Sperm morphology correlates with sperm-ZP binding, and sperm concentration correlates with ZP-induced AR in infertile men with sperm concentrations >20 x 10(6)/mL. Defective ZP-induced AR may cause infertility in up to 25% men with idiopathic infertility. These patients require ICSI despite the normal standard semen analyses. CONCLUSION(S): Sperm-oocyte interaction tests are useful for diagnosis of subtle sperm defects that cause infertility in men without severe abnormalities of semen analysis. Pre-IVF diagnosis of these sperm defects will assist in the clinical assignment of patients to treatment with either standard IVF or ICSI.

Embryo Transfer↗