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Results for “data reproducibility”

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At least 19 recordsLinked to original sources

PubMed1992

Reproducibility of data obtained by a newly developed anterior eye segment analysis system, EAS-1000.

The reproducibility of data obtained from the recently developed anterior eye segment analysis system (EAS-1000) was evaluated. 40 normal eyes and 62 cataractous eyes were examined at Kanazawa Medical University Hospital or Yayoi Hospital. The radius of the corneal curvature, the corneal thickness, anterior chamber depth, whole lens thickness, anterior chamber angle and the scattering light intensity were all observed on a slit section of the lens, and the intrapupillary area of the cataractous shadow was measured from a retroillumination image. The measurements were made twice at an interval of 14.2 days. There were no significant differences between the data of the 1st and 2nd examination in either place.

Adolescent↗

PubMed1992

Reproducibility of data from a hand-held digital pulp tester used on teeth and oral soft tissue.

Controlled studies of the reproducibility of data from electronic pulp testing instruments are limited and contain few statistical analyses. The reproducibility of these readings is important if the instrument is to be used for determining differences in sensitivity. Twenty human subjects (16 male) were used in this study. One incisor, one premolar, one molar tooth with small or no restorations, and two gingival soft tissue positions from each upper and lower arch of each subject were stimulated with the Analytic Technology vitality scanner. This procedure was repeated twice with a 5-minute rest between each trial, for a total of three trials. Each subject was then seen again after a period of at least 3 days, at which time the trials were repeated. The collected data were grouped by trial, tooth position, and day. Paired t test analysis of both the absolute difference between any two trials on the same day and the average of the absolute differences between corresponding trials on days 1 and 2 showed no statistically significant differences (p greater than 0.05). Accommodation to the stimulus was evaluated by examining differences in the mean values between the three same-day trials. The Analytic Technology vitality scanner was found to be reproducible both for consecutive same-day trials and for corresponding trials on different days. No same-day trends in meter readings were noted.

Adult↗

PubMed1977

Reproducibility of data on steady-state gas exchange and indices of maldistribution of ventilation and blood flow.

The reproducibility of data on steady-state gas exchange and arterial blood gas levels was examined in 45 patients with similar pathophysiologic abnormalities (idiopathic scoliosis) by comparing the data obtained during two sequential periods breathing air. Comparison in all patients of 12 variables by paired t-test demonstrated statistically significant differences in the following three variables: the ratio of physiologic dead space to tidal volume (Vd/TV), the alveolar-arterial oxygen pressure difference (P[A-a]O2), and the arterial oxygen tension. By excluding four patients whose respiratory quotient was greater than two standard deviations from the mean value and one patient with a marked change in the pattern of ventilation, only the Vd/TV was significantly different (P less than 0.05). The range of the coefficients of variation was wide. The highest, which was for P(A-a)O2, was 18.8 percent; the majority were in range of 6 to 13 percent (minute ventilation, TV, frequency, oxygen consumption and carbon dioxide production, respiratory quotient, Vd/TV, dead space, and alveolar ventilation), and the coefficients of variation of partial pressure of oxygen and carbon dioxide in the arterial blood were, respectively, 3.6 and 3.4 percent.

Blood Gas Analysis↗

PubMed2026

Community-driven advances in computational mass spectrometry: The perspective of EuBIC-MS members.

Advances in data acquisition, artificial intelligence, and integrative bioinformatics are driving the rapid evolution of computational mass spectrometry, and in turn, transforming modern proteomics, metabolomics, and lipidomics. These developments have greatly increased the scale and complexity of mass spectrometry data, underscoring the importance of evolving accurate, transparent, efficient and reproducible data processing workflows. Addressing these challenges requires collaborative innovation that brings together expertise in software engineering, statistics, and biology. The European Bioinformatics Community for Mass Spectrometry (EuBIC-MS), an initiative of the European Proteomics Association (EuPA), fosters a culture of open, community-driven development through its biennial Developers Meetings and Winter Schools. This commentary summarizes the scientific background and outcomes of the EuBIC-MS Developers Meeting 2025, which took place in Novacella, Italy. Three keynote presentations highlighted major frontiers in the field: deep proteome and phosphoproteome profiling, text mining for protein-protein interaction extraction, and scalable proteomics for AI-driven drug discovery. Seven community-selected hackathons addressed emerging challenges such as single-cell proteomics data analysis, FAIR metadata extraction, deep learning frameworks, R-Python interoperability, and DIA validation. Together, these efforts demonstrate the potential for scientific and technical innovation to arise from open collaboration, and highlight how community-driven initiatives can accelerate progress in computational mass spectrometry. SIGNIFICANCE: Modern proteomics increasingly depends on computational advances to translate complex, high-dimensional data into biological knowledge. The EuBIC-MS Developers Meeting 2025 exemplifies how community-driven collaboration can directly accelerate this process by bringing together experts from bioinformatics, statistics, and experimental proteomics to co-develop open, interoperable, and reproducible analytical tools. By fostering shared software frameworks, transparent benchmarking, and collaborative problem solving, the EuBIC-MS community helps ensure that technological innovation translates into reliable biological insights. This collaborative model strengthens the foundation for quantitative, system-level understanding of proteomes and establishes a sustainable path for integrating artificial intelligence and next-generation data acquisition into routine biological discovery. This commentary shows some current highlights in the field of computational mass spectrometry and community-based approaches undertaken during the most recent Developers Meeting to solve these challenges. The approaches discussed and initiated during the meeting - ranging from deep proteome profiling and phosphosite mapping to text mining, single-cell data analysis, and FAIR metadata extraction - address key bottlenecks that currently limit the biological interpretability and comparability of proteomics data.

Mass Spectrometry↗

PubMed1991

Tandem mass spectrometry of peptides using hybrid and four-sector instruments: a comparative study.

Product-ion spectra produced by high- and low-energy collisionally activated dissociation (CAD) of [M + H]+ ions of a series of peptides (Mr 550-2500) have been compared on four-sector and hybrid tandem mass spectrometers, respectively. The fast atom bombardment product-ion spectra obtained for the smallest peptide analyzed (methionine-enkephalin) were remarkably similar, but substantial differences in fragmentation were observed for the heavier analytes. For peptides with Mr greater than 1000, more complete sequence information was obtained from high-energy CAD on the four-sector instrument. Nevertheless, low-energy CAD on the hybrid mass spectrometer was able to produce partial sequence information even for the largest of the peptides compared. Limits of analysis, defined as the least quantities of analyte for which product-ion spectra of essentially uncompromised quality could be obtained, were similar (ca. 15 pmol) for small peptides, but lower limits were achieved for larger peptides (Mr greater than 1000) with the four-sector instrument. High-energy CAD spectra were found to be highly reproducible, with qualitatively similar spectra obtained over a wide range of operating conditions. In contrast, it was necessary to carefully control collision gas pressures and collision energies in order to obtain good reproducible data for low-energy CAD. Experimental procedures for obtaining reproducible spectra with good sensitivity for peptides on the hybrid instrument are presented.

Adrenocorticotropic Hormone↗

PubMed1978

A scheme for the evaluation of methods in clinical chemistry with particular application to those measuring enzyme activities. Part II: analysis of data and performance assessment.

Recommendations are made concerning the editing of day-to-day reproducibility data for establishment of precision in the evaluation of a clinical chemistry method. The concept of diagnostic and equalized diagnostic indices is introduced together with formulae for their generation from the usual precision and accuracy data acquired in method evaluations. These indices allow direct comparison of data obtained from procedures for measuring enzyme activities which employ a variety of experimental conditions and units in their protocols. The equalized diagnostic index permits assessment of the suitability of the normal range assignment. Permissible limits of variation (PLV) and permissible limits of discrepancy (PLD) have been developed empirically from detailed examination of data from method evaluations and proficiency testing surveys in the published literature. The application of the diagnostic indices and the two permissible limits of criteria have been illustrated using data from the assessment of 19 kits measuring CPK activity. The inconsistency of the correlation coefficient in method comparisons is confirmed.

Canada↗

PubMedDate not supplied

Syringing as a method of cell dispersal. I. Effect on intermediate and superficial squamous cells.

Mechanical shear in the form of syringing was applied to human gynecologic cytology specimens in an effort to disperse cell clumps. The percentage of single squamous cells achieved with the optimum conditions is generally 70 to 100 per cent. Syringing with a constant pressure device produces a high yield of single squamous cells without the concurrent high cell loss as often observed using enzymatic or chemical procedures. Data presented demonstrate that the slide preparation and clump evaluation procedures used for this study yield reliable and reproducible data. Studies varying stroke number and plunger pressure were completed and conditions for maximum dispersal were established.

Cell Separation↗

PubMed1979

[Evaluation of accuracy comparing three types of urological manometers (author's transl)].

Manometrical examinations of the female urinary bladder are important in the field of urodynamic diagnosis. Accuracy in these measurements is a prerequisite for the reproducibility of the results. In this study, three types of urological manometers, differing in their principles of measurement, were tested for their physical and technical properties. Pressure was measured with a membrane manometer (instrument A) with Statham elements (instrument B), and with a micro-transducer (instrument C). The results using Statham elements and micro-transducers were exactly reproducible and varied only in their interference with external factors, which affect the quality of the results in clinical routine. Concerning the physical technique of measurement, instrument C with micro-transducers gives the most accurate results and is the easiest one to manage. For research and clinical routine it is superior to instrument B. It supplies reproducible data which are independent of external parameters such as the patient's position, attention and the way the instrument is set up. Our results only urodynamical measurements using micro-transducers can be taken as absolute measurements of excellent accuracy and are comparable among themselves as well as with other absolute measurements for long-term series of measurement. Using a membrane manometer (instrument A), measurements were hardly reproducible so that these results can be accepted as orienting data only.

Evaluation Studies as Topic↗

PubMed1992

High-performance liquid chromatographic determination of 2-furaldehyde in spirits.

Official methods for the determination of 2-furaldehyde in spirits involve for a spectrophotometric evaluation, which is characterized by poor specificity. Gas chromatographic evaluations have also been proposed, which offer a much higher sensitivity, particularly when capillary columns are used. In this paper a high-performance liquid chromatographic (HPLC) method based on the formation of the 2,4-dinitrophenylhydrazones of carbonyl compounds and subsequent reversed-phase separation of these derivatives is described. Derivatization is carried out by utilizing an acidic solution of 2,4-dinitrophenylhydrazine in acetonitrile. Precipitation of the derivatives is avoided and direct injection of the sample into the HPLC system is allowed. The determination offers a high specificity and a detection limit of the order of 10(-8) mol/l. Accuracy and reproducibility data are presented.

Alcoholic Beverages↗

PubMed1992

Measurement variability in duplex scan assessment of carotid atherosclerosis.

BACKGROUND AND PURPOSE: The reproducibility of duplex scan measures of carotid atherosclerosis was evaluated as part of a study assessing the prevalence of carotid disease in elderly adults. METHODS: Doppler measures of blood flow velocity were used to evaluate disease severity, and extent of carotid plaque was scored from the B-mode image. A reader assigned a grade from 0 to 3 to each of seven segments in the carotid system, based on the number and size of lesions present. Reproducibility data were obtained from 30 study participants who underwent a repeat scan by a second sonographer. Each scan was then scored by two readers. RESULTS: Doppler measures of blood flow velocity were found to be highly reproducible, with intraclass correlation coefficients of 0.81 for the common carotid artery, 0.84 for the internal carotid artery, and 0.77 for the internal carotid artery velocity to common carotid artery velocity ratio. Reproducibility of plaque grade was evaluated using segment as the unit of analysis, and both sonographer and reader variation were analyzed. When readers differed perfect agreement was achieved in 84% of the segments (K = 0.67), and when sonographers differed perfect agreement was obtained in 78% of the segments (K = 0.56). When both sonographer and reader differed, perfect agreement was obtained in 77% of the segments (K = 0.53). The plaque index, created by summing plaque grades from selected segments, was highly reproducible, with an intraclass correlation coefficient of 0.86. CONCLUSIONS: The duplex scan protocol described here provides reliable measures of both extent and severity of carotid disease that are appropriate for use in cross-sectional studies.

Aged↗

PubMed1991

[Clinical application of evoked otoacoustic emission].

Evaluations were made concerning the efficiency and location of the optimal index values of the e-OAE recording method of ILO88 on 10 normal hearing subjects and 10 subjects having inner ear hearing loss. Furthermore, noise from the surrounding environment, noise made during the time of measurement, and the depth of probe insertion into the external auditory meatus as well as the type of probe tip used, were also studied in relation to its effect on the e-OAE recording method in 5 other normal hearing subjects. The results were as follows; 1) Total echo power (TEP) and the highest peak between the 1-2kHz frequency range (HPP1-2) were considered to be the optimal index values for ILO88. 2) The surrounding noise did not cause any significant change in the TEP and HPP1-2 values. 3) Noise during the actual measurement by the patient did not cause any significant change in the TEP and HPP1-2 values. 4) The depth of probe insertion into the external auditory meatus had no significant effect upon the TEP and HPP1-2 values. 5) Data reproducibility was difficult and e-OAE power was less for the pinch pump type ear cuff compared to the rubber and silicon probe tips. In conclusion, TEP and HPP1-2 were considered to be the optimal index values for ILO88, and with the use of an appropriate probe tip, it is possible to obtain accurate data with the application of the e-OAE recording method regardless of external noise from the surrounding environment or by patients such as infants.

Acoustic Stimulation↗

PubMed1992

Leukocyte membrane markers on cell populations defined by six flow cytometric bitmaps.

Peripheral blood samples from healthy adults, patients with transplanted bone marrow, and healthy children were analyzed for the proportions of cells positive for CD2, CD4, CD8, CD19, CD56, CDw65, and KiM8 cell membrane markers. Six cell gates were defined on granularity vs. cell size (L90 degrees LSx-FALS) flow cytometric display for each blood sample: large lymphocytic, small lymphocytic, monocytic, mononuclear, granulocytic, and all-cell gate, and the listed markers were determined in each of them. Considerable differences in marker-positive cell proportions were found between healthy adults and children, and particularly between healthy adults and patients with transplanted bone marrow. Marker-positive cell frequencies corresponded to biologic distribution of three leukocyte populations within the defined gates, in a general agreement with known specificities of the antibodies used. A considerable degree of variations in the positions of gates drawn for different samples and the numbers of cells counted in them was observed. Still it appeared that all six gates, otherwise commonly used in flow cytometric analysis, could be precisely defined and yielded reproducible data. large and small lymphocytic gates yielded very similar marker frequencies, revealing that in cases where three leukocyte populations were not clearly delineated on (90 degrees LSxFALS) display, a smaller lymphocytic gate could be safely drawn in order to avoid contamination with monocytes.

Adult↗

PubMed1977

Electron-capture GLC determination of nanogram to picogram amounts of isosorbide dinitrate.

A GLC method for the determination of plasma isosorbide dinitrate using electron-capture detection is described. The organic nitrates are especially suited for electron-capture detection if the detector temperature is optimized for maximum sensitivity, e.g., 175 degrees. Proper maintenance of the detector and column assures reproducible data in the low nanogram range. The extraction procedure described is simple, efficient, and expedient for processing large numbers of samples. The method was used to study plasma levels in four human volunteers after a single dose of a 5-mg chewable isosorbide dinitrate tablet. Concentration levels of isosorbide dinitrate as low as 0.5 ng/ml of plasma can be measured by this procedure.

Adult↗

PubMed1991

Morphometry of the corpus callosum in normal aging and Alzheimer's disease.

Changes of the human corpus callosum in normal aging and Alzheimer's disease were analysed by means of morphometry. A standardized computerized evaluation program was implemented allowing objective, quantitative and reproducible data. The various parts of the corpus callosum showed a different pattern of changes in normal aging as compared to Alzheimer's disease. In conclusion, in normal aging affects mostly the front-temporal interhemispheric fiber systems, whereas in Alzheimer's disease the parietotemporal commissural fibers are altered.

Aging↗

PubMed1979

Application of linear system analysis to the horizontal vestibulo-ocular reflex of the alert rhesus monkey using pseudorandom binary sequence and single frequency sinusoidal stimulation.

Horizontal eye movements of the alert rhesus monkey resulting from both pseudorandom binary sequence (PRBS) and single frequency sinusoidal rotational stimulation were analyzed using a PDP 11/40 computer in order to generate gain, phase, and coherence estimates at discrete frequencies between 0.008 and 1.28 Hz. A computer simulation of vestibular induced eye movements was used to validate our analysis procedures and to determine the effects of digital noise. Frequency domain transfer functions derived from gain and phase estimates revealed that the responses to PRBS stimulation and to single frequency sinusoids were not appreciably different. PRBS testing was accomplished in approximately one third the time required for sinusoidal testing and yielded highly reproducible data. We conclude that PRBS stimulation is a reliable and efficient method for assessing linear system parameters of the horizontal vestibulo-ocular reflex. PRBS testing may be particularly advantageous in studies of vestibulo-oculomotor plasticity in which rapid assessment of alterations in system dynamics is essential.

Animals↗

PubMed1979

Determination of erythrocyte amino acids by gas chromatography.

Erythrocyte amino acid levels were determined, by gas chromatography, in a group of 34 normal human adults. No significant sex or age correlations were noted. A method for the quantitative gas chromatographic analysis of free amino acids in erythrocytes is described. Following hemolysis and deproteinization the amino acids were isolated on a cation-exchange resin. Glutathione was removed from the amino acid mixture by adsorption on an anion-exchange resin. Following conversion to their N-acetyl-n-propyl esters, 19 amino acids were separated and quantitated by gas chromatography on a single column in 18 min. Typical reproducibility data indicate that a coefficient of variation of 2-5% is attainable.

Adult↗

PubMedDate not supplied

Surface tension of therapeutic surfactants (exosurf neonatal, infasurf, and survanta) as evaluated by standard methods and criteria.

Three commercial preparations for the treatment of neonatal respiratory distress syndrome (NRDS), Exosurf Neonatal (EX), Infasurf (IN), and Survanta (SU), were studied at 37 degrees C in both a pulsating bubble surfactometer and a vertical film surface balance. "Static" characteristics of adsorbed films were assessed with "bubble" at maximum radius (Rmax) and at minimum radius (Rmin). Adsorption time was time to stable film formation (gamma equilibrium). In dynamic experiments, the bubble was cycled (compressed-decompressed) between Rmax and Rmin at 20, 40, and 80 cpm. Spread films were cycled in the surface balance between maximum area (Amax) and minimum area (A(min)) at 1.5 cpm. In all experiments, maximum surface tension (gamma max) coincided with Rmax or Amax and gamma min with Rmin or A(min). All trials were continued until gamma max and gamma min were reproducible. Data were evaluated according to standard criteria for normal function both in vivo and in vitro of lipid mixtures (EX) or natural surfactants (IN, SU) prepared for treatment of NRDS. All preparations failed two of the four criteria, adsorption in the time of a deep breath and maintenance of stable, low gamma. Adsorption required 10 to 20 seconds and stable gamma was achieved only at equilibrium gamma, > 17 mN/m. IN and SU conformed in general to two criteria, gamma approaching zero on compression and low surface compressibility (< 0.09 m/mN), whereas spontaneously formed films of EX did not. EX was idiosyncratic in that these two criteria were met only after an apparent change of film conformation had been effected, possibly related to elimination of preparation additives from the surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Products↗

PubMed1977

Tension generation by threads of contractile proteins.

Threads of contractile proteins were formed via extrusion and their isometric tensions and isotonic contraction velocities were measured. We obtained reproducible data by using a new and sensitive tensiometer. The force-velocity curves of actomyosin threads were similar to those of muscle, with isometric tensions of the order of 10g/cm2 and maximum contraction velocites of the order of 10(-2) lengths/s. The data could be fitted by Hill's equation. Addition of tropomyosin and troponin to the threads increased isometric tension and maximum contraction velocity. Threads which contained troponin and tropomyosin required Ca++ for contraction and the dependence of their isometric tension on the level of free Ca++ was like that of muscle. The dependence of tension or of contraction velocity upon temperature or upon ionic strength is similar for actomyosin threads and muscle fibers. In contrast, the dependence of most parameters which are characteristic of the actomyosin interaction in solution (or suspension) upon these variables is not similar to the dependence of the muscle fiber parameters. The conclusion we have drawn from these results is that the mechanism of tension generation in the threads is similar to the mechanism that exists in muscle. Because the protein composition of the thread system can be manipulated readily and because the tensions and velocities of the threads can be related directly to the physiological parameters of muscle fibers, the threads provide a powerful method for studying contractile proteins.

Actins↗