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PubMed1999

Quality through metrics.

The Quality Assurance Unit analyzed 18 months of departmental data regarding the report-audit cycle. Process mapping was utilized to identify milestones in the cycle for measurement. Five milestones were identified in the audit cycle, as follows: (1) time from report receipt in quality assurance to start of audit, (2) total calendar days to audit a report, (3) actual person-hours to perform a report audit, (4) time from completion of audit to issuance of report, and (5) total time a report is in quality assurance. An interrelationship diagraph is a quality tool that is used to identify what activities impact the overall report-auditing process. Once the data collection procedure is defined, a spreadsheet is constructed that captures the data. The resulting information is presented in time charts and bar graphs to visually aid in interpretation and analysis. Using these quality tools and statistical analyses, the Quality Assurance Unit identified areas needing improvement and confirmed or dispelled previous assumptions regarding the report-auditing process. By mapping, measuring, analyzing, and displaying the data, the overall process was examined critically. This resulted in the identification of areas needing improvement and a greater understanding of the report-audit cycle. A further benefit from our increased knowledge was the ability to explain our findings objectively to our client groups. This sharing of information gave impetus to our clients to examine their report-generation process and to make improvements.

Data Collection↗
PubMed2003

Simultaneous determination of hydroxycinnamates and catechins in human urine samples by column switching liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry.

A quantitative liquid chromatography mass spectrometry (LC-MS) methodology with online sample clean up by column switching is described for the simultaneous determination of the hydroxycinnamates, caffeic acid and chlorogenic acid, and of the catechins, epicatechin and catechin in human urine samples. Enzymatically treated urine samples were directly injected onto the LC-MS system, where sample clean up was performed by a reversed-phase Zorbax 300SB C(3) column and selective elution of the target compounds onto a Zorbax SB C(18) column resulted in final separation prior to detection by atmospheric pressure chemical ionization (APCI) MS using single ion monitoring (SIM) in negative mode. Linear calibration graphs were achieved in the dynamic range of 10-1000 ng/ml urine. The inter- and intraassay coefficients of variation (C.V.%) for the analysis of the four compounds in quality control urine samples were between 7.8 and 10.9, n=17 (reproducibility), and the repeatability of the assay was between 2.5 and 5.0% (n=12). Analyses of urine samples from a human dietary intervention study with intake of 600 g of fruits and vegetables were demonstrated. To our knowledge, this is the first method described that allows simultaneous determination of both hydroxycinnamates and catechins in biological samples.

Atmospheric Pressure↗
PubMed1996

Should Common Optimal Movement Patterns Be Identified as the Criterion to Be Achieved?

Recently, a new paradigm has been proposed for the study of knowledge of performance (Schmidt & Young, 1991). In this paradigm, the experimenters identified an optimal kinematic movement pattern, based on the performance of a best subject, which was imposed on all subjects as the criterion to achieve. This approach, which assumes that this pattern is the best way for all subjects to do the task, was tested in the present experiment. In Experiment 1, a common optimal movement pattern could not be identified by an analysis of scatterplot graphs of the scores plotted as a function of various kinematic vanables or by correlating (within and across subjects [N = 14]) each kinematic variable with the score. In Experiment 2, subjects (N = 12) were retrained in 2 separate sessions, during which they tried to reproduce either a personal best or the best subject's template. Results indicated that scores were similar regardless of the template pattern being used. During training, however, subjects who used their personal template had a lower incidence of zero scores and were more consistent than those who used the template of the best subject. This provided a second line of evidence against the assumption that a common optimal movement pattern exists for this type of task.

Journal Article↗
PubMed1991

A laser densitometer for selective spot analysis on dot blots and two-dimensional gel autoradiograms.

We describe an inexpensive densitometer, employing a small HeNe laser and an IBM-compatible personal computer that performs accurate measurements of selected spots on two-dimensional gel autoradiograms or chromatograms with an accuracy and a sensitivity equal or superior to those of many commercial instruments. Our open-table design allows the operator to visually monitor the scanning process in room lighting, and provides great flexibility in both the size and the nature of items to be scanned. The instrument has two moving parts (a prism and a small motor). A commercially available software package (ASYST) acquires digital data, graphs the data on the TV monitor, converts the data to optical density or to radioactive incorporation (cpm), subtracts background, integrates peak areas, and stores data on disk. The total time for these operations is 20-30 s per spot. The instrument has a dynamic range of 0.25 to 3.0 OD units and can measure a 10,000-fold range of 14C or 35S isotope concentrations on autoradiograms. The complete device can be assembled with a hobbyist's knowledge of electronics, moderate programming abilities (no machine language required), and a cost of less than $3000, not including the IBM PC.

Costs and Cost Analysis↗
PubMed1995

Mathematical model of oxygen transport: a teaching aid for normal physiology adaptable to extracorporeal oxygenation circuits.

The ultimate aim of most intensive care therapies is to improve tissue oxygen delivery; consequently, a detailed knowledge of this area of physiology is important to a wide range of Critical Care Staff. We describe a simple mathematical model of oxygen transport that was initially written as a training aid for extracorporeal oxygenation training. The model has subsequently proved useful for explaining the determinants of oxygen transport to a broader audience. It is based on simple linear equations and is easily displayed with a standard computer spreadsheet. Apart from its teaching value, the model can also generate a graph of oxygen saturation vs. inspired oxygen fraction for different degrees of pulmonary shunt. This provides a noninvasive method for determining the magnitude of pulmonary venous admixture and may also prove to have some clinical value.

Biological Transport, Active↗
PubMedDate not supplied

A formal model of family medicine.

BACKGROUND: The American Board of Family Practice is developing a computer-based recertification process. An optimal implementation requires a formal model of family medicine, which will become the basis for a knowledge base. DESIGN: The proposed model of family medicine contains six entities: Population, Record, Agents of Change, Health States, Findings, and Courses of Action. The model illustrates 15 important relations between entities. For instance: Health States Lead to Health States, and Findings Associate with Health States. These two relations describe natural history, manifestations of disease, and the effects of medical interventions and risk factors. Because time is such an important aspect of primary care, nearly all numeric data are represented as graphs of possible values over time, called Patterns, which include details about periodicity. Patterns and other aspects of the model provide a means of describing covariance between observations, such as the influence of height on weight. RESULTS: The model reflects many family practice activities and suggests some formal descriptions of family practice. For instance, diagnostic activities focus largely on classifying early or short segments of Patterns in Findings. Most medical interventions attempt to alter either the probability distributions in a Lead-to relation or the impact of a Finding. CONCLUSION: The proposed model of family medicine could find uses in many applications, including computer-based tests, medical records, reference systems, and decision support tools.

Family Practice↗
PubMed2003

Statistical shape analysis of neuroanatomical structures based on medial models.

Knowledge about the biological variability of anatomical objects is essential for statistical shape analysis and discrimination between healthy and pathological structures. This paper describes a novel approach that incorporates the variability of an object population into the generation of a characteristic 3D shape model. The proposed shape representation is a coarse-scale sampled medial description derived from a fine-scale spherical harmonics (SPHARM) boundary description. This medial description is composed of a net of medial samples (m-rep) with fixed graph properties. The medial model is computed automatically from a predefined shape space using pruned 3D Voronoi skeletons. A new method determines the stable medial branching topology from the shape space. An intrinsic coordinate system and an implicit correspondence between shapes is defined on the medial manifold. Several studies of biological structures clearly demonstrate that the novel representation has the promise to describe shape changes in a natural and intuitive way. A new medial shape similarity study of group differences between monozygotic and dizygotic twins in lateral ventricle shape demonstrates the meaningful and powerful representation of local and global form.

Algorithms↗
PubMed1992

Mathematical assessment of the spatial distribution of Langerhans cells in guinea pig epidermis.

Two mathematical indexes, Hopkins-Skellam index (HSI) and Morisita index (MI), were applied to assess the distribution of ATPase-stained epidermal Langerhans cells (ELC) in the guinea pig skin. To our knowledge, this is the first report in which the degree of regularity has been expressed numerically by computation based on theoretical equations. The regularity of ELC in the normal skin was confirmed by the value of HSI (P < 0.0001). In the topical steroid applied skin, the number of ELC decreased significantly but the value of HSI was similar to that of the normal skin; while in the ultraviolet B (UVB) exposed skin, both number of ELC and regularity of ELC distribution decreased significantly. The graph of MI for the UVB exposed skin clearly showed that the distribution of ELC had local clumps. The two indexes, HSI and MI have been quite useful for determining the regularity of ELC. These indexes may have a wide application to other cells.

Animals↗
PubMed1988

Biological applications of the SAS system: an overview.

The SAS system provides biologists with a flexible, easy to use software package for data analysis. Through a combination of data management tools, a wide variety of pre-programmed procedures for sorting, graphing, and statistical analysis and a sophisticated programming language, SAS software can perform all analytical needs for most problems. The recent availability of SAS software on mainframes other than IBM, and more recently on the microcomputer, means that most scientists can have access to the software. In this review we discuss the structure of the SAS language and demonstrate its power in the analysis of biological problems. Although to a lesser extent now than originally, the SAS system is statistically oriented and a working knowledge of statistics is recommended before using its statistical capabilities. However, all biologists will find its data management and summarization capabilities very useful.

Biology↗
PubMed2002

Feature subset selection for splice site prediction.

MOTIVATION: The large amount of available annotated Arabidopsis thaliana sequences allows the induction of splice site prediction models with supervised learning algorithms (see Haussler (1998) for a review and references). These algorithms need information sources or features from which the models can be computed. For splice site prediction, the features we consider in this study are the presence or absence of certain nucleotides in close proximity to the splice site. Since it is not known how many and which nucleotides are relevant for splice site prediction, the set of features is chosen large enough such that the probability that all relevant information sources are in the set is very high. Using only those features that are relevant for constructing a splice site prediction system might improve the system and might also provide us with useful biological knowledge. Using fewer features will of course also improve the prediction speed of the system. RESULTS: A wrapper-based feature subset selection algorithm using a support vector machine or a naive Bayes prediction method was evaluated against the traditional method for selecting features relevant for splice site prediction. Our results show that this wrapper approach selects features that improve the performance against the use of all features and against the use of the features selected by the traditional method. AVAILABILITY: The data and additional interactive graphs on the selected feature subsets are available at http://www.psb.rug.ac.be/gps

Arabidopsis↗
PubMed1976

Clinical trials in surgery.

Scientific knowledge is reliable because it has been built on accurate measurements. Clinical knowledge is not. The science of biometry was started in 1835 by the Belgian astronomer Adolphe Quetelet. In the last fifty years a precise set of rules have been invented for this science. The method is suitable for a wide range of problems in clinical medicine and as the result of its application in recent years a firm foundation has been laid upon which scientific clinical knowledge can be built. Surge-ns, particularly, have been slow to apply biometrical methods to their clinical problems; but a start has now been made. The outcome of a particular type of treatment is determined by a complex set of inter-acting factors. The basis of the appropriate biometrical method is the elimination of all bias in favour of one of the rival techniques being compared. If this precaution is taken the observed results of the trial can be fitted onto Quetelet's distribution graph, and the probability of the observed difference in the results being due to chance, and nothing else, can be measured mathematically. The accuracy of this measurement deteriorates the greater are the number of the patients who can not be found and examined at the end of the trial. To make this point two trials conducted by the author are used. In the trial designed to discover if postoperative deep vein thrombosis and pulmonary embolism could be prevented by electrically stimulating the patients legs during the operation there was no difficulty. All the patients were examined at the end of the trial, because it ended before any of the patients left the hospital. The trial to discover if the primary treatment of varicose veins ought to be by Fegan's sclerotherapy or by operation was the exact opposite. At the end of the first year of the two year trial 15% of the patients could not be traced. The results in these patients, therefore, was unknown. Because of this, elaborate mathematical calculations had to be made to try and reach a reliable conclusion to the trial. The loss of patients before the end of the trial is a very serious practical difficulty which besets all long-term clinical trials.

Clinical Trials as Topic↗
PubMed1993

A hybrid system for diagnosing multiple disorders.

This paper investigates the advantages of introducing feedback between the processes of automated medical diagnosis and automated diagnostic-knowledge acquisition. Experimental results show that a diagnostic system with such feedback is capable of an efficiency/accuracy trade-off when applied to the problem of diagnosing multiple disorders. A primary feature of this work is a new mechanism, called the "diagnostic-unit" representation, for remembering results of previous diagnoses. The diagnostic-unit representation is explicitly tailored to capture the most likely relationships between disorders and clusters of findings. Unlike typical bipartite "If-Then" representations, the diagnostic-unit representation uses a general graph representation to efficiently represent complex causal relationships between disorders and clusters of findings. In addition to the basic diagnostic-unit concept, this paper presents experience-based strategies for incrementally deriving and updating diagnostic units and the various relationships between them. Techniques for selecting diagnostic units relevant to a given problem and then combining them to generate solutions are also described.

Artificial Intelligence↗
PubMed2000

Combinatorial explosion in model gene networks.

The explosive growth in knowledge of the genome of humans and other organisms leaves open the question of how the functioning of genes in interacting networks is coordinated for orderly activity. One approach to this problem is to study mathematical properties of abstract network models that capture the logical structures of gene networks. The principal issue is to understand how particular patterns of activity can result from particular network structures, and what types of behavior are possible. We study idealized models in which the logical structure of the network is explicitly represented by Boolean functions that can be represented by directed graphs on n-cubes, but which are continuous in time and described by differential equations, rather than being updated synchronously via a discrete clock. The equations are piecewise linear, which allows significant analysis and facilitates rapid integration along trajectories. We first give a combinatorial solution to the question of how many distinct logical structures exist for n-dimensional networks, showing that the number increases very rapidly with n. We then outline analytic methods that can be used to establish the existence, stability and periods of periodic orbits corresponding to particular cycles on the n-cube. We use these methods to confirm the existence of limit cycles discovered in a sample of a million randomly generated structures of networks of 4 genes. Even with only 4 genes, at least several hundred different patterns of stable periodic behavior are possible, many of them surprisingly complex. We discuss ways of further classifying these periodic behaviors, showing that small mutations (reversal of one or a few edges on the n-cube) need not destroy the stability of a limit cycle. Although these networks are very simple as models of gene networks, their mathematical transparency reveals relationships between structure and behavior, they suggest that the possibilities for orderly dynamics in such networks are extremely rich and they offer novel ways to think about how mutations can alter dynamics. (c) 2000 American Institute of Physics.

Journal Article↗
PubMedDate not supplied

[The effect of knowledge regarding the importance of oral health in pregnancy].

INTRODUCTION: Although in modern dental medicine a pregnant woman and her foetus are completely safe during all dental procedures, the prevention is still the most effective measure for the preservation of oral health in pregnancy. However, pregnant women often visit a stomatologist only when there are already serious disturbances, regardless of the fact that they are referred to a stomatologist even at their first visit to a gynaecologist. The aim of the study was to investigate (possible) changes in pregnant women's attitudes toward oral health during pregnancy according to our educational programme. METHODS: One hundred and sixty pregnant patients were randomly selected for the educational programme and were enrolled in the study. In direct contact (groups of 4 to 14 pregnant patients) they received basic information about the condition for attaining and maintaining their and foetal good health [1]. In order to establish the results, three anonymous questionnaires were conducted. Two of them made the questionnaire A because of identical results obtained before and after the education, and the third questionnaire B was different, and was conducted at the end. The questionnaire B concerned the personal point of view of pregnant women about the obtained information [2]. RESULTS: The results of the first two questionnaires (questionnaire A) are shown in Graph with a quantity of correct answers expressed in percents. The results of the questionnaire B are formulated according to answers to a question with "YES" and "NO", and they are expressed in percentage. The following results were obtained for questionnaire B: A hundred percent of pregnant women stated that they had learned something new about oral health, 67 percent had immediately changed their nutrition for healthy food, 100 percent of them understood well the significant role of fluor prophylaxis, 16 percent did not accept it for unknown reasons, but 100 percent thought that it was very useful to hear lectures about oral health [3]. DISCUSSION: A great interest existed for all preventive stomatologic measures and dental procedures during pregnancy, which formerly, as a rule, were avoided because of ignorance [4]. It is necessary to carry out a proper prevention, and adequately inform and motivate pregnant women, so that we could have a satisfied mother and carefree child in the future.

Attitude to Health↗
PubMedDate not supplied

[Perception of risk for infection with the human immunodeficiency virus].

Prevention of AIDS is very complex and requires, apart from basic knowledge about modes of transmission and protection, individual awareness of personal risk of infection and modification of one's risky behavior. Perception of risk has been suggested as an important element of sexual behavior change among people who engage in behaviors that place them at risk of HIV infection. This study investigates perceived risk of an HIV infection among inhabitants of municipality of Palilula. The purpose of this study was to determine the relative accuracy of risk assessment, especially for those with high-risk sexual behavior and to assess the factors related to self perception of developing AIDS. The survey was conducted as a household survey in Belgrade municipality "Palilula". The design of the survey was based on a two-stage stratified random sample. The population of Palilula municipality was divided in two stratums and 840 households were selected from each stratum. All members of selected households aged 15-49 years were interviewed. Total of 2659 persons was interviewed. Self administered questionnaire, developed by WHO and described in the Evaluation of National AIDS Programme: A Methods Package 1. Prevention of HIV infection, Geneva, 1994, was translated and adapted for local application. For analysis of findings methods of descriptive statistics, chi square test and logistic regression were used. Statistical analysis was performed using SPSS/PC. The results showed that most of the respondents (1662, 62.5%) do not perceive themselves to be at risk of HIV infection. Interestingly, almost one quarter of the sample couldn't estimate personal chances of being HIV infected. Significantly larger proportion of respondents living in urban area than those living in rural area perceived themselves at risk (17.1% of urban vs. 7.7% from rural area, chi square = 54.06, Ir0.00). Significant differences between age groups were found for perception of personal risk. Respondents up to 19 and those older than 25 in more than 60 percent and only a half of those between 20 and 24 believed that there was no chance they could become HIV infected. Almost 16% of respondents between 20 and 24 believed that they had some chances of contracting HIV, also approximately one third of them couldn't estimate personal risk of contracting HIV infection (chi square = 2.10, p = 0.00)(Graphe 1). Those who engaged in sex with irregular partners were found to perceive themselves in higher risk then those who were engaged in sex only with regular partners in previous 12 months. One fifth of those with irregular partners estimated their chances as good versus only 10% of those with only regular partners. A logistic regression analysis found that those who believed they were personally at risk knew someone with HIV, had more irregular sexual partners in last 12 months, were younger, and lived in urban area (Table 1). People correctly perceived the risk of HIV infection as being minimal as most of them didn't engage in risk behavior. Risk perception was higher among those who had more irregular partners, younger and those from urban area. Most important predictor of risk perception was knowledge of HIV positive individual.

Adolescent↗
PubMed1986

The biomechanics of the long jump.

The preceding review has been based on over 200 publications in Czech, English, French, German, Japanese, Polish, and Russian. Even a cursory perusal of these materials is sufficient to show that much has been done to try and obtain a scientific understanding of long jump techniques. It is clear, too, that still more remains to be done. Much of the work to date has been focused on just a few aspects of long jump technique. Other important aspects have received relatively little attention. The latter include the accuracy of the approach, the techniques used during the final strides of the approach, the role of elastic energy in the takeoff, the initiation and control of the jumper's angular momentum, and the techniques used in the landing. Future research efforts might well be directed towards resolving major issues concerning these aspects of long jump technique. The methods used to gather data in the studies reviewed have been rather unimaginative. Two-dimensional cinematography has been used in the vast majority of the studies and force platforms in a few. Other data-gathering procedures like three-dimensional cinematography, electromyography and accelerometry have rarely, if ever, been used. In only one or two studies was anything remotely approaching experimental or technological innovation in evidence. The methods used to analyze data have also been very limited. With the notable exception of a study by Ballreich, few papers have involved anything more sophisticated than means, standard deviations, correlation coefficients and an occasional multiple regression equation. Given these facts, it is hard to avoid the conclusion that our knowledge of long jump techniques might be greatly improved if the full range of available and appropriate procedures were turned to the purpose. Finally, no review of the literature on long jump techniques would be complete without reference to the level of scholarship displayed in the works under consideration. With only a few exceptions, the level shown in the scientific papers reviewed here left much to be desired. Time and again, variables were not defined, crucial measurement techniques were not described and major results were not presented or discussed. In addition, much of the data presented in tables and graphs were patently in error. In light of all this, it is clear that unless the level of scholarship improves, future progress in this area of sports biomechanics is likely to be very slow.

Biomechanical Phenomena↗
PubMed2002

Integrated visualization of problemcentric urologic patient records.

The collision of computer-based technologies and the medical environment is resulting in an increasingly electronic multimedia patient record, consisting of not only the traditional types of data (e.g., clinic notes and laboratory reports), but also digital images (e.g., computed tomography and magnetic resonance imaging) and other visual representations of patient data (e.g., pulmonary function graphs and urodynamic charts). Given the increasing amount of data made available to physicians, it is not only critical that the totality of a patient's medical record be accessible to a clinician, but that the diverse data be integrated and presented in a manner conducive to patient management: key information should be easily discovered. This paper describes a problemcentric time-based visualization of urologic conditions, whereby a patient's medical history is automatically organized around a medical problem and presented as a graphic chronology. Urology-related data in the patient medical record is organized in accord with an expert constructed knowledge-base, and plotted on a timeline using iconic representations. The user interface permits the physician to quickly view multimedia data and to visualize relationships between events in the patient's history.

Computer Systems↗
PubMed2002

Elastic properties of proteins: insight on the folding process and evolutionary selection of native structures.

We carry out a theoretical study of the vibrational and relaxation properties of naturally occurring proteins with the purpose of characterizing both the folding and equilibrium thermodynamics. By means of a suitable model, we provide a full characterization of the spectrum and eigenmodes of vibration at various temperatures by merely exploiting the knowledge of the protein native structure. It is shown that the rate at which perturbations decay at the folding transition correlates well with experimental folding rates. This validation is carried out on a list of about 30 two-state folders. Furthermore, the qualitative analysis of residues mean square displacements (shown to reproduce crystallographic data accurately) provides a reliable and statistically accurate method to identify crucial folding sites/contacts. This novel strategy is validated against clinical data for human immunodeficiency virus type 1 (HIV-1) protease. Finally, we compare the spectra and eigenmodes of vibration of natural proteins against randomly generated compact structures and regular random graphs. The comparison reveals a distinctive enhanced flexibility of natural structures accompanied by slow relaxation times at the folding temperature. The fact that these properties are connected intimately to the presence and assembly of secondary motifs hints at the special criteria adopted by evolution in the selection of viable folds.

Biological Evolution↗