Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Data Analytics”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Bioanalytic considerations for pharmacokinetic and biopharmaceutic studies.

The correct evaluation of pharmacokinetic and biopharmaceutic data can only be achieved if accurate analytic data are obtained. The accuracy of analytic data depends on the criteria used to validate the method. Consequently, careful scrutiny of drug stability, assay sensitivity, selectivity, recovery, linearity, precision, and accuracy is necessary for the proper interpretation of data. The importance of method validation and its influence on pharmacokinetic and biopharmaceutic data evaluation and interpretation will be discussed.

Biopharmaceutics↗
PubMed1997

Protecting the integrity of clinical laboratory test results.

The authors' inspection reports demonstrate that the improper alteration of patient data is not a rare aberration in private commercial clinical laboratories. Although laboratory surveyors could be trained to recognize this problem, the availability of unprotected test systems makes even trained inspectors ineffectual. Both regulatory agencies and professional accrediting agencies should be concerned that their surveyors may be placing a seal of approval on what are, in reality, compromised or even fabricated data. In proposing the regulations discussed in this paper, the FDA sought to "preserve the integrity of the agency's enforcement process." This goal will remain unattainable, however, until a mechanism has been devised to secure the original raw data produced by all of the analytical systems being used not only in clinical laboratories but also in environmental laboratories, pharmaceutical laboratories, etc. Laboratories, as well as regulatory agencies and accrediting bodies, need to be concerned on behalf of the patient, but laboratories may also need to be concerned on their own behalf. In the coming era of unprecedented cost constraints and competitive bidding, unscrupulous testing facilities or groups of such facilities could have a significant edge over their conscientious competitors if the issues raised here continue to be ignored. Although the analytical data management systems provide tremendous benefits, some have serious problems in ensuring the security of their data. However, if regulatory agencies, accrediting bodies, professional organizations, and the analyzer vendors make a united commitment, the problem of securing the integrity of analytical data could eventually be resolved. It is hoped that such a commitment will be made in the near future.

Autoanalysis↗
PubMed1986

Pattern recognition used to investigate multivariate data in analytical chemistry.

Pattern recognition and allied multivariate methods provide an approach to the interpretation of the multivariate data often encountered in analytical chemistry. Widely used methods include mapping and display, discriminant development, clustering, and modeling. Each has been applied to a variety of chemical problems, and examples are given. The results of two recent studies are shown, a classification of subjects as normal or cystic fibrosis heterozygotes and simulation of chemical shifts of carbon-13 nuclear magnetic resonance spectra by linear model equations.

Carbon Radioisotopes↗
PubMed1996

Assessment of chromatographic peak purity by means of artificial neural networks.

An improved chemometric approach is proposed for assessing chromatographic peak purity by means of artificial neural networks. A non-linear transformation function with a back-propagation algorithm was used to describe and predict the chromatographic data. The Mann-Whitney U-test was used for the concluding the purity of the chromatographic peak. Simulation data and practical analytical data for both pure and mixture samples were analysed with satisfactory results. A prior knowledge of the impurity and the related compound is unnecessary when a slight difference between their chromatogram and spectrum exists. The performance on simulated data sets by this approach was compared with the results from principal component analysis.

Algorithms↗
PubMed1990

Personality variables as mediators and moderators of family history risk for alcoholism: conceptual and methodological issues.

Recently there has been great interest in possible mediators and moderators of family history risk for alcoholism. However, previous studies have failed to employ appropriate designs and data analytic strategies to identify moderators and mediators. This article uses a large data set to illustrate such analyses. In the current data, both presumed personality risk and dispositional self-awareness were found to play moderator (rather than mediator) roles. The conceptual, methodological and data analytic implications of the mediator-moderator distinction are discussed.

Adolescent↗
PubMed2001

The need for mixed-effects modeling with population dichotomous data.

Over the past 25 years sophisticated data analytic techniques have been developed which can lead to improved analyses, but at additional computational cost. In particular, this applies to the approach where interindividual random effects are included in a data analytic model for population pharmacokinetic data, which can often lead to substantially improved estimates of fixed-effect parameters. However, there are also commonly occurring situations, notably with some types of pharmacodynamic data, where such improvement is not realized. This study simulates some simple population dichotomous data, and secondarily, some related continuous data. These data are analyzed using both mixed-effect (ME) models that include interindividual random effects and naive (NA) models that do not include interindividual random effects, and it is seen that use of an ME model does not inevitably lead to gains over use of an NA model. In fact, using maximum likelihood estimation with both types of models, the root mean square estimation errors for fixed effect parameters can actually be larger with an ME model than with the corresponding NA model. Using a form of restricted maximum likelihood estimation with the ME model, the two types of models yield root mean square errors which are comparable, but which still do not suggest that there is always marked advantage in using the ME model.

Humans↗
PubMed2003

CytometryML, an XML format based on DICOM and FCS for analytical cytology data.

BACKGROUND: Flow Cytometry Standard (FCS) was initially created to standardize the software researchers use to analyze, transmit, and store data produced by flow cytometers and sorters. Because of the clinical utility of flow cytometry, it is necessary to have a standard consistent with the requirements of medical regulatory agencies. METHODS: We extended the existing mapping of FCS to the Digital Imaging and Communications in Medicine (DICOM) standard to include list-mode data produced by flow cytometry, laser scanning cytometry, and microscopic image cytometry. FCS list-mode was mapped to the DICOM Waveform Information Object. We created a collection of Extensible Markup Language (XML) schemas to express the DICOM analytical cytologic text-based data types except for large binary objects. We also developed a cytometry markup language, CytometryML, in an open environment subject to continuous peer review. RESULTS: The feasibility of expressing the data contained in FCS, including list-mode in DICOM, was demonstrated; and a preliminary mapping for list-mode data in the form of XML schemas and documents was completed. DICOM permitted the creation of indices that can be used to rapidly locate in a list-mode file the cells that are members of a subset. DICOM and its coding schemes for other medical standards can be represented by XML schemas, which can be combined with other relevant XML applications, such as Mathematical Markup Language (MathML). CONCLUSIONS: The use of XML format based on DICOM for analytical cytology met most of the previously specified requirements and appears capable of meeting the others; therefore, the present FCS should be retired and replaced by an open, XML-based, standard CytometryML.

Computer Communication Networks↗
PubMed1997

Air pollution and the deterioration of historic monuments.

The results of air pollution surveys conducted at two sites in the historic center of Rome and at two sites in Latium are summarized and illustrated. The objective of our study is to identify a link between the analytical data and brightness measurements of outdoor stone monuments in the selected areas. The analytical data coincide well with the characteristics of the sites with heavy traffic (Rome and Villa d'Este in Tivoli) when compared with the "zero level exposure" of the Villa Adriana.

Air Pollution↗
PubMed1991

Chiral drugs: an industrial analytical perspective.

In the pharmaceutical industry, chiral drug candidates introduce a unique set of challenges to all disciplines involved in the drug development process. For the analytical chemist in particular, the generation of relevant information about a variety of stereoisomeric issues is necessary. Chiral drug candidates, whether a single isomer or a mixture of isomers, require more analytical information than achiral drug candidates. This information can be derived from enantioselective spectroscopic and chromatographic techniques. Chiral analytical methods require proper development and validation to ensure accurate results. Issues related to method development and validation for complete stereochemical characterization are discussed, with primary emphasis on the generation of analytical data required for the registration of a chiral drug candidate. The presentation of pertinent analytical data depends on an awareness of the problems encountered during the development process and the appropriate use of methodology for the determination of stereoisomeric purity.

Animals↗
PubMed1998

Quality assurance in veterinary diagnostic laboratories.

The authors discuss the responsibility of veterinary diagnostic laboratories as suppliers of analytical data for tests on animals and animal products. The guarantee of the quality of analytical data is a basic quality requirement for veterinary certification. It is therefore important for the laboratory to adopt operational quality assurance standards which are recognised internationally. The management and quality assurance criteria contained in the International Standardisation Organisation/International Electrotechnical Commission Guide 25, or in directives or guidelines established by international organisations such as the Office International des Epizooties and the Codex Alimentarius of the Food and Agriculture Organisation, are reviewed. These documents provide procedures for adopting the principles of quality assurance in order to acquire the recognition of competence to execute the laboratory tests required for national and international veterinary certification.

Animals↗
PubMed1985

Toxicity modeling and prediction with pattern recognition.

Empirical models can be constructed relating the change in toxicity to the change in chemical structure for series of similar compounds or mixtures. The first step is to translate the variation in structure to quantitative numbers. This gives a data table, a data matrix denoted by X, which then is analyzed. The same type of the models can be used to relate the variation of in vivo data to the variation of a battery of in vitro tests. A single data analytical model cannot be applied to a set of compounds of diverse chemical structure. For such data sets, separate models must be developed for each subgroup of compounds. The data analytical problem then partly is one of classification, pattern recognition (PARC). The assumption of structural and biological similarity within each subset of modeled compounds is then essential for empirical models to apply. PARC is often used to classify compounds as active (toxic) or inactive. The data structure is then often asymmetric which puts special demands on the data analysis, making the traditional PARC methods inapplicable. Depending on the desired information from the data analysis and on the type of available data, four levels of PARC can be distinguished: (I) the data X are used to develop rules for classifying future compounds into one of the classes represented in X; (II) same as I, but the possibility of future compounds belonging to "unknown" classes not represented in X is taken into account; (III) same as II, plus the quantitative prediction of one activity variable (here toxicity) in some classes; (IV) same as III, but several quantitative activity (toxicity) variables are predicted.

Mathematics↗
PubMed1991

Integrated approach for designing medical decision support systems with knowledge extracted from clinical databases by statistical methods.

In clinical research data is often studied by a particular method without previous analysis of quality or semantic contents which could link clinical database and data analytical (e.g. statistical) procedures. In order to avoid bias caused by this situation, we propose that the analysis of medical data should be divided into two main steps. In the first one we concentrate on conducting the quality, semantic and structure analyses. In the second step our aim is to build an appropriate dictionary of data analysis methods for further knowledge extraction. Methods like robust statistical techniques, procedures for mixed continuous and discrete data, fuzzy linguistic approach, machine learning and neural networks can be included. The results may be evaluated both using test samples and applying other relevant data-analytical techniques to the particular problem under the study.

Artificial Intelligence↗
PubMed1990

Psychotherapy process research: progress, dilemmas, and future directions.

The first several decades of psychotherapy process research have produced advances in measure development and substantive findings of process-outcome relations. A recent paradigm shift toward sequentially patterned, significant change episodes is described, emphasizing segmentation of process by meaningful patterns wherever they occur. Theoretical, psychometric, and data analytic dilemma are reviewed. Strategies are offered that may enhance future research efforts. These include greater attention to construct validity of measures, the relation of process to phase-specific outcome criteria, and the continuing development of multivariate data analytic strategies that take into account Patient X Treatment interactions as well as the sequential dependency of process data. The development of a national archive of significant change events is recommended to advance modeling of the change process, segmentation, construct validation of measures, integration of qualitative and quantitative approaches, and development of a cross-theoretical language for therapy process.

Follow-Up Studies↗
PubMed1993

Analytical and biological data of banked samples--a requirement to interpret accumulation and leaching of pollutants in biological specimens.

The accumulation of organic and inorganic pollutants in biological specimens depends, in many cases, not only on the atmospheric deposition or immission and contamination of the biotop, but also on the dynamic properties of the indicator. Thus the analytical data assume properties of process variables. In order to compare them in relation to space and time, it is often practical to refer them to defined conditions of the indicator (stationary phases, time cycles of low dynamics). If the accumulation varies consistently under identical conditions of contamination and if clear functional relations exist to the features of the indicator, for instance age, weight or ecological processes, it is necessary to normalize the analytical data, i.e. to refer them to a condition of the indicator which is defined meaningfully with regard to the ecology. Interactions with other inputs of substances may result in a differentiation of accumulation and leaching processes which is more or less specific for each element. Such knowledge is important for specifying the standard operation procedures and the evaluation as well as interpretation of analytic data, in particular, in the clarification of the ecotoxicological relations between the pollutant accumulation and the reaction of populations and ecosystems.

Animals↗
PubMed2002

Recent developments in food characterization and adulteration detection: technique-oriented perspectives.

This review covers mainly publications that appeared in Analytical Abstracts (Royal Society of Chemistry) from January 1990 to February 2001. The number of publications on this topic continues to grow, and during the past three years (1998-2000) about 150 reviews and/or overviews have been published in the area of food. Numerous techniques and food matrices or chemical components are presented and discussed in these reviews. The present review is intentionally limited to eight techniques or classes of techniques and intends to be a "technique by technique" presentation of "what was used" or "what is used" to characterize food products and to detect their possible adulteration. The present review focuses on the following techniques: microscopic analysis; HPLC; GC, GC-(MS, FTIR); UV-visible spectrophotometry; AAS/AES, ICP-(AES, MS); IRMS, GC-IRMS, GC-C-IRMS; DSC; IR, mid-IR, and NMR (202 references). Emphasis is placed as much as possible on chemometrical treatment of analytical data, which are commonly used to achieve the final objective, either food characterization or adulteration detection. Finally, a brief description is given of the new generation of analytical systems that combine powerful analytical techniques and powerful computer software for a best extraction of the information from analytical data.

Calorimetry, Differential Scanning↗
PubMed2000

Estimation of structural wave numbers from spatially sparse response measurements.

A method is presented for estimating the complex wave numbers and amplitudes of waves that propagate in damped structures, such as beams, plates, and shells. The analytical basis of the method is a wave field that approximates response measurements in an aperture where no excitations are applied. At each frequency, the method iteratively adjusts wave numbers to best approximate response measurements, using wave numbers at neighboring frequencies as initial estimates in the search. In comparison to existing methods, the method generally requires far fewer measurement locations and does not require evenly spaced locations. The number of locations required by the method scales with the number of waves that propagate in the structure, whereas the number of locations required by existing methods scales with the minimum wavelength. In addition, the method allows convenient inclusion of the analytic relationships between wave numbers that exist for flexural vibrations of beams and plates. Advantages of the method are illustrated by an example in which a beam is excited by a transverse force at one end. Using analytic data and experimental measurements, the method produces a wave field that matches response measurements to within 1 percent. One interesting feature of the new method is that, when applied to analytic data, it supplies more robust wave number estimates using responses at unevenly spaced locations.

Acoustics↗
PubMed2001

Measurement of near zero concentration: recording and reporting results that fall close to or below the detection limit.

Issues relating to the recording and reporting of analytical data obtained where the concentration of analyte is around or below the detection limit are discussed. The following recommendations are proposed. Analytical results should be recorded by the analyst exactly as they occur, including any negative results, and such records retained for an appropriate length of time. For the purposes of quality assurance in the laboratory (including method validation, internal quality control, and proficiency testing), negative results should be used as they stand. Analytical results reported to a customer should be accompanied by a statement of uncertainty including, in the present context, uncertainty at low concentrations of analyte. The method of editing of reported results must be a contractual matter between the analyst and the customer, but a statement of the procedure used should accompany the results and should be explicit. Normally such editing should be restricted to setting negative results to zero. The customer should be encouraged to pass on the statement to all end users. Data intended for the public domain should be accompanied by a statement detailing the uncertainty, the method of editing, and the location of the unedited data. Most types of statistical processing of datasets containing low concentrations of analyte should be undertaken on the unedited data.

Journal Article↗