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PubMedDate not supplied

A cluster analysis to investigating nurses' knowledge, attitudes, and skills regarding the clinical management system.

Nurses' knowledge, attitudes, and skills regarding the Clinical Management System are explored by identifying profiles of nurses working in Hong Kong. A total of 282 nurses from four hospitals completed a self-reported questionnaire during the period from December 2004 to May 2005. Two-step cluster analysis yielded two clusters. The first cluster (n = 159, 56.4%) was labeled "negative attitudes, less skillful, and average knowledge" group. The second cluster (n = 123, 43.6%) was labeled "positive attitudes, good knowledge, but less skillful." There was a positive correlation in cluster 1 for nurses' knowledge and attitudes (rs = 0.28) and in cluster 2 for nurses' skills and attitudes (rs = 0.25) toward computerization. The study showed that senior and more highly educated nurses generally held more positive attitudes to computerization, whereas the attitudes among younger and less well educated nurses generally were more negative. Such findings should be used to formulate strategies to encourage nurses to resolve actual problems following computer training and to increase the depth and breadth of nurses' computer knowledge and skills and improve their attitudes toward computerization.

Cluster Analysis↗
PubMed2000

Convection in two-layer systems with an anomalous thermocapillary effect

Recently, it was found that the anomalous thermocapillary effect (the interfacial tension increases with temperature) is typical for various liquid-liquid systems. We consider the combined action of buoyancy and thermocapillary instability mechanisms in systems with an anomalous thermocapillary effect on the interface. The problem is solved in both linear and nonlinear formulations. A special type of oscillatory instability has been found and investigated.

Journal Article↗
PubMed1998

A Kalman filter approach to track fast impedance changes in electrical impedance tomography.

In electrical impedance tomography (EIT), an estimate for the cross-sectional impedance distribution is obtained from the body by using current and voltage measurements made from the boundary. All well-known reconstruction algorithms use a full set of independent current patterns for each reconstruction. In some applications, the impedance changes may be so fast that information on the time evolution of the impedance distribution is either lost or severely blurred. In this paper, we propose an algorithm for EIT reconstruction that is able to track fast changes in the impedance distribution. The method is based on the formulation of EIT as a state-estimation problem and the recursive estimation of the state with the aid of the Kalman filter. The performance of the proposed method is evaluated with a simulation of human thorax in a situation in which the impedances of the ventricles change rapidly. We show that with optimal current patterns and proper parameterization, the proposed approach yields significant enhancement of the temporal resolution over the conventional reconstruction strategy.

Algorithms↗
PubMed2005

Image up-sampling using total-variation regularization with a new observation model.

This paper presents a new formulation of the regularized image up-sampling problem that incorporates models of the image acquisition and display processes. We give a new analytic perspective that justifies the use of total-variation regularization from a signal processing perspective, based on an analysis that specifies the requirements of edge-directed filtering. This approach leads to a new data fidelity term that has been coupled with a total-variation regularizer to yield our objective function. This objective function is minimized using a level-sets motion that is based on the level-set method, with two types of motion that interact simultaneously. A new choice of these motions leads to a stable solution scheme that has a unique minimum. One aspect of the human visual system, perceptual uniformity, is treated in accordance with the linear nature of the data fidelity term. The method was implemented and has been verified to provide improved results, yielding crisp edges without introducing ringing or other artifacts.

Algorithms↗
PubMed2002

A support vector machine approach for detection of microcalcifications.

In this paper, we investigate an approach based on support vector machines (SVMs) for detection of microcalcification (MC) clusters in digital mammograms, and propose a successive enhancement learning scheme for improved performance. SVM is a machine-learning method, based on the principle of structural risk minimization, which performs well when applied to data outside the training set. We formulate MC detection as a supervised-learning problem and apply SVM to develop the detection algorithm. We use the SVM to detect at each location in the image whether an MC is present or not. We tested the proposed method using a database of 76 clinical mammograms containing 1120 MCs. We use free-response receiver operating characteristic curves to evaluate detection performance, and compare the proposed algorithm with several existing methods. In our experiments, the proposed SVM framework outperformed all the other methods tested. In particular, a sensitivity as high as 94% was achieved by the SVM method at an error rate of one false-positive cluster per image. The ability of SVM to out perform several well-known methods developed for the widely studied problem of MC detection suggests that SVM is a promising technique for object detection in a medical imaging application.

Algorithms↗
PubMed2005

Relevance vector machine for automatic detection of clustered microcalcifications.

Clustered microcalcifications (MC) in mammograms can be an important early sign of breast cancer in women. Their accurate detection is important in computer-aided detection (CADe). In this paper, we propose the use of a recently developed machine-learning technique--relevance vector machine (RVM)--for detection of MCs in digital mammograms. RVM is based on Bayesian estimation theory, of which a distinctive feature is that it can yield a sparse decision function that is defined by only a very small number of so-called relevance vectors. By exploiting this sparse property of the RVM, we develop computerized detection algorithms that are not only accurate but also computationally efficient for MC detection in mammograms. We formulate MC detection as a supervised-learning problem, and apply RVM as a classifier to determine at each location in the mammogram if an MC object is present or not. To increase the computation speed further, we develop a two-stage classification network, in which a computationally much simpler linear RVM classifier is applied first to quickly eliminate the overwhelming majority, non-MC pixels in a mammogram from any further consideration. The proposed method is evaluated using a database of 141 clinical mammograms (all containing MCs), and compared with a well-tested support vector machine (SVM) classifier. The detection performance is evaluated using free-response receiver operating characteristic (FROC) curves. It is demonstrated in our experiments that the RVM classifier could greatly reduce the computational complexity of the SVM while maintaining its best detection accuracy. In particular, the two-stage RVM approach could reduce the detection time from 250 s for SVM to 7.26 s for a mammogram (nearly 35-fold reduction). Thus, the proposed RVM classifier is more advantageous for real-time processing of MC clusters in mammograms.

Algorithms↗
PubMedDate not supplied

Occlusion-free animation of driving routes for car navigation systems.

This paper presents a method for occlusion-free animation of geographical landmarks, and its application to a new type of car navigation system in which driving routes of interest are always visible. This is achieved by animating a nonperspective image where geographical landmarks such as mountain tops and roads are rendered as if they are seen from different viewpoints. The technical contribution of this paper lies in formulating the nonperspective terrain navigation as an inverse problem of continuously deforming a 3D terrain surface from the 2D screen arrangement of its associated geographical landmarks. The present approach provides a perceptually reasonable compromise between the navigation clarity and visual realism where the corresponding nonperspective view is fully augmented by assigning appropriate textures and shading effects to the terrain surface according to its geometry. An eye tracking experiment is conducted to prove that the present approach actually exhibits visually-pleasing navigation frames while users can clearly recognize the shape of the driving route without occlusion, together with the spatial configuration of geographical landmarks in its neighborhood.

Journal Article↗
PubMed1987

Field trial of the effectiveness of indoor-spraying with pirimiphos-methyl emulsion for malaria control in a tribal area of Phulbani district, Orissa State, India.

A field trial of malaria vector control was conducted in Phulbani district, Orissa, during 1984 and 1985. Indoor-spraying of pirimiphos-methyl emulsion formulation was undertaken at an application rate of 2 g/m2 in two sections (population 14,692) of Nuagaon Primary Health Centre. Houses in two adjacent sections (population 21,450) were sprayed with DDT a water dispersible powder (wdp) formulation at 1 g/m2 for comparison purposes. Operational problems in this area come from the tendency of tribal people to re-plaster over wdp applications. Pre-spray malariological indices in the trial area were 38% slide positivity rate, 37% slide falciparum rate and 12.1% annual parasite incidence. Densities of Anopheles annularis Van der Wulp, An. culicifacies Giles, An. fluviatilis Theobald and other potential malaria vectors were reduced in the pirimiphos-methyl trial area 2-35-fold more than in the area sprayed with DDT. Malariological indices were reduced by 65-68% in the pirimiphos-methyl sprayed area compared with only 26-35% reduction in the DDT sprayed area. Spraymen and villagers experienced no adverse side-effects from residual house-spraying with pirimiphos-methyl emulsion and it is concluded that this organophosphate product has advantages for malaria vector control, especially in operationally difficult situations.

Aerosols↗
PubMed1995

Rehabilitation planning for flood affected areas of Thailand: experience from Phipun District.

Floods are common in Thailand. A flood in the southern part of the country in 1988 was of unprecedented magnitude. Several villages and vast tracts of agricultural land were covered with mud slides washed away from deforested hills. Rehabilitation of the affected areas, a task which required complex planning, was a challenge for the District Development Committee (DDC), which is the local level planning body. The Committee encountered several problems, including inability to use the existing data base and lack of accurate information, human resources, adequate funds and coordination among agencies. Unable to cope with the new challenges, the DDC resorted to conventional planning which failed to address the problems caused by the flood. Guidelines should be formulated to strengthen district level planning for rehabilitation after a disaster.

Community Participation↗
PubMed2000

Rectal absorption of lamotrigine compressed tablets.

PURPOSE: Interruption of oral drug administration poses a significant clinical problem for antiepileptic drugs that have no parenteral formulation. If a drug is absorbed rectally, rectal administration can be a useful alternative when the oral route of administration is not possible. The purpose of this study was to compare the single-dose pharmacokinetics of lamotrigine (LTG) compressed tablets after rectal and oral administration in healthy volunteers. METHODS: A single LTG compressed tablet (100 mg) was administered orally and rectally to 12 volunteers in this single-dose, two-period, crossover study with a 2-week washout between doses. For rectal administration, tablets were crushed and suspended in 10 mL of water. Plasma samples were collected from 0 to 120 hr after each dose and analyzed for LTG by an HPLC method developed for this investigation. RESULTS: LTG plasma concentrations were lower after rectal administration versus oral administration. The average area under the curve was 28.90 +/- 9.5 microg/mL/hr after rectal administration and 51.71 +/- 19.2 microg/mL/hr after oral administration. The average maximum LTG concentration was 0.53 +/- 0.14 microg/mL after rectal administration and 1.45 +/- 0.35 microg/mL after oral administration. The relative bioavailability for LTG compressed tablets was 0.63 +/- 0.33 for rectal administration. There were no drug-related rashes or serious side effects. CONCLUSIONS: LTG suspension prepared from LTG compressed tablets is absorbed rectally, although not to the same extent or rate as when given orally.

Administration, Oral↗
PubMed2001

Bordetella pertussis fimbriae are effective carrier proteins in Neisseria meningitidis serogroup C conjugate vaccines.

Serogroup C meningococcal conjugate vaccines generally use diphtheria or tetanus toxoids as the protein carriers. The use of alternative carrier proteins may allow multivalent conjugate vaccines to be formulated into a single injection and circumvent potential problems of immune suppression in primed individuals. Bordetella pertussis fimbriae were assessed as carrier proteins for Neisseria meningitidis serogroup C polysaccharide. Fimbriae were conjugated to the polysaccharide using modifications of published methods and characterised by size exclusion chromatography; co-elution of protein and polysaccharide moieties confirmed conjugation. The conjugates elicited boostable IgG responses to fimbriae and serogroup C polysaccharide in mice, and IgG:IgM ratios indicated that the responses were thymus-dependent. High bactericidal antibody titres against a serogroup C strain of N. meningitidis were also observed. In a mouse infection model, the conjugate vaccine protected against lethal infection with N. meningitidis. Therefore, B. pertussis fimbriae are effective carrier proteins for meningococcal serogroup C polysaccharide and could produce a vaccine to protect against meningococcal disease and to augment protection against pertussis.

Animals↗
PubMed2004

An iterative effective medium approximation (IEMA) for wave dispersion and attenuation predictions in particulate composites, suspensions and emulsions.

In the present work we deal with the scattering dispersion and attenuation of elastic waves in different types of nonhomogeneous media. The iterative effective medium approximation based on a single scattering consideration, for the estimation of wave dispersion and attenuation, proposed in Tsinopoulos et al., [Adv. Compos. Lett. 9, 193-200 (2000)] is examined herein not only for solid components but for liquid suspensions as well. The iterations are conducted by means of the classical relation of Waterman and Truell, while the self-consistent condition proposed by Kim et al. [J. Acoust. Soc. Am. 97, 1380-1388 (1995)] is used for the convergence of the iterative procedure. The single scattering problem is solved using the Ying and Truell formulation, which with a minor modification can accommodate the solution of scattering on inclusions in liquid. Theoretical results for several different systems of particulates and suspensions are presented being in excellent agreement with experimental data taken from the literature.

Journal Article↗
PubMed1990

Inhaled micronised gentamicin powder: a new delivery system.

Forty patients undergoing routine bronchoscopy were randomised to receive inhaled micronised gentamicin powder (180 mg) or nebulised gentamicin solution (160 mg) one hour before the procedure. Similar levels of gentamicin were detected in bronchoalveolar lavage fluid in the two groups (micronised powder (n = 20) 9.3 (SD 9.3) mg/l, nebulised solution (n = 20) 8.0 (7.8) mg/l). The micronised gentamicin powder preparation caused cough in half the patients but this did not stop their receiving a full dose. Dry powder gentamicin may be a convenient formulation for long term inhaled treatment if the problem of cough can be overcome.

Administration, Inhalation↗
PubMed2002

Ionic mechanism of electrical alternans.

Although alternans of action potential duration (APD) is a robust feature of the rapidly paced canine ventricle, currently available ionic models of cardiac myocytes do not recreate this phenomenon. To address this problem, we developed a new ionic model using formulations of currents based on previous models and recent experimental data. Compared with existing models, the inward rectifier K(+) current (I(K1)) was decreased at depolarized potentials, the maximum conductance and rectification of the rapid component of the delayed rectifier K(+) current (I(Kr)) were increased, and I(Kr) activation kinetics were slowed. The slow component of the delayed rectifier K(+) current (I(Ks)) was increased in magnitude and activation shifted to less positive voltages, and the L-type Ca(2+) current (I(Ca)) was modified to produce a smaller, more rapidly inactivating current. Finally, a simplified form of intracellular calcium dynamics was adopted. In this model, APD alternans occurred at cycle lengths = 150-210 ms, with a maximum alternans amplitude of 39 ms. APD alternans was suppressed by decreasing I(Ca) magnitude or calcium-induced inactivation and by increasing the magnitude of I(K1), I(Kr), or I(Ks). These results establish an ionic basis for APD alternans, which should facilitate the development of pharmacological approaches to eliminating alternans.

Action Potentials↗
PubMed1975

A biological basis for the Oedipus complex: an evolutionary and ethological approach.

The authors propose that the Oedipus complex has a strong biological basis that is evident in observations of human prehistoric and nonhuman primate behavior. The groundwork for the oedipal phase is the peaking of human infantile sexuality at age five or six-a vestige of an earlier biological timetable. Other contributing factors include the high level of helplessness of human infants, the resulting high attachment needs, and the prolongation of development phases. Unsuccessful resolution of the oedipal phase may result when the mother's dominant status is lowered. The authors suggest that an understanding of the relationship between sex and rank and an wareness of ethological findings can broaden psychodynamic formulations and enrich the psychoanalytic therapy of sexual problems.

Adolescent↗
PubMedDate not supplied

Factored stochastic trees: a tool for solving complex temporal medical decision models.

The stochastic tree is a continuous-time version of a Markov-cycle tree, useful for constructing and solving medical decision models in which risks of mortality and morbidity may extend over time. Stochastic trees have advantages over Markov-cycle trees in graphic display and computational solution. Like the decision tree or Markov-cycle tree, stochastic tree models of complex medical decision problems can be too large for convenient graphic formulation and display. This paper introduces the notion of factoring a large stochastic tree into simpler components, each of which may be easily displayed. It also shows how the rollback solution procedure for unfactored stochastic trees may be conveniently adapted to solve factored trees. These concepts are illustrated using published examples from the medical literature.

Decision Trees↗
PubMed2004

Epothilones: mechanism of action and biologic activity.

Drugs that target microtubules are among the most commonly prescribed anticancer therapies. Although the mechanisms by which perturbation of microtubule function leads to selective death of cancer cells remain unclear, several new microtubule-targeting compounds are undergoing clinical testing. In part, these efforts focus on overcoming some of the problems associated with taxane-based therapies, including formulation and administration difficulties and susceptibility to resistance conferred by P-glycoprotein. Epothilones have emerged from these efforts as a promising new class of anticancer drugs. Preclinical studies indicate that epothilones bind to and stabilize microtubules in a manner similar but not identical to that of paclitaxel and that epothilones are effective in paclitaxel-resistant tumor models. Clinical phase I and early phase II data are available for BMS-247550, BMS-310705, EPO906, and KOS-862. The results suggest that these compounds have a broad range of antitumor activity at doses and schedules associated with tolerable side effects.

Antineoplastic Agents↗
PubMed1981

Objectives, standards, and evaluation in long-term care.

Objectives commonly considered in evaluation of long-term care programs are critically reviewed. An alternate formulation, in which assurance of adequate solutions to problems of daily living is the basic purpose of long-term care, is proposed. Conceptual and methodological issues in systematic description of quality of circumstances of the functionally disabled are discussed. An approach to developing standards for quality of community-based long-term care is outlined. Consideration is given to the role of organized and publicly financed long-term care in reducing care burdens experienced by family members.

Evaluation Studies as Topic↗