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At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

Gravimetric determination of amylase-treated neutral detergent fiber in feeds with refluxing in beakers or crucibles: collaborative study.

As an important constituent of animal feeds, fiber represents the portion of feeds that is bulky and difficult to digest. The neutral detergent fiber (NDF) method, developed over 30 years ago, is the method of choice for measuring total fiber in forages and other feeds. Several modifications that were made to improve its general applicability to all feeds and others developed in individual laboratories often resulted in variability among laboratories in measuring NDF. The amylase-treated NDF (aNDF) method, therefore, was developed as an accurate and precise method of measuring total insoluble fiber in feeds. A collaborative study was conducted to evaluate the repeatability and reproducibility of the aNDF method over the full range of animal feed materials. Twelve laboratories representing research, feed company, regulatory, and commercial feed testing laboratories analyzed 11 materials as blind duplicates. The materials represented feed matrixes, including animal products; high-protein, high-fat, and high-pectin feeds; oil seeds; grains; heated by-product feeds; and legume and grass hays and silages. Materials selected varied in chemical composition and contained 0-90% aNDF, 1-16% ash, 1-20% crude fat, 1-40% crude protein, and 0-50% starch. Correcting results for changes in blanks and reporting results as ash-free aNDF organic matter (aNDFom) improved the repeatability and reproducibility of results when aNDF was <25%. The within-laboratory repeatability standard deviation (Sr) for percentage aNDFom in feeds varied from 0.21 to 1.82 and among-laboratory reproducibility standard deviation (S(R)) varied from 0.37 to 2.24. The HORRAT was <2 for all materials except feed materials containing >10% fat. However, standard deviations of repeatability and reproducibility for feeds with >10% fat were similar to those of other materials. It is recommended that the aNDF method be accepted for Official First Action status.

Algorithms↗
PubMed1993

Reproducibility of the cortisol response to stimulation with a low dose of ACTH(1-24): the effect of basal cortisol levels and comparison of low-dose with high-dose secretory dynamics.

We compared the reproducibility and repeatability of the acute adrenal response to low doses (90 and 500 ng/1.73 m2) of Synacthen (ACTH(1-24)) with that of the standard dose (250 micrograms/1.73 m2). We also examined the effect of basal cortisol levels on peak values achieved after stimulation with a low dose. ACTH(1-24) was given to six male volunteers: 90 ng/1.73 m2 twice at 90-min intervals on day 1, and 90 and 500 ng/1.73 m2 once on day 2 and 250 micrograms/1.73 m2 once on day 3. The rise in serum cortisol concentration with repeated low doses of ACTH was not attenuated (161 +/- 49 (S.D.) nmol/l on initial vs 150 +/- 41 nmol/l on repeat stimulation; P = 0.5) and this was reproducible (161 +/- 49 nmol/l on day 1 vs 148 +/- 15 nmol/l on day 2; P = 0.6). A dose of 500 ng ACTH(1-24)/1.73 m2 produced a maximal adrenal response in that the rise in serum cortisol concentration at 20 min was identical with that produced at the same time by the standard dose of 250 micrograms/1.73 m2. There was a strong positive correlation between the basal cortisol level and peak cortisol concentration after low-dose ACTH stimulation (r = 0.93, P < 0.001) but not between the basal cortisol level and the incremental rise (r = -0.1, P = 0.69). These results suggest that the cortisol response to low-dose ACTH stimulation is reproducible and not attenuated by repeat stimulation at 90-min intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗
PubMedDate not supplied

Enzymatic-ultraviolet determination of glucose and fructose in wine: collaborative study.

This collaborative study on the determination of glucose and fructose in wine was performed by 18 laboratories on 4 matched pairs of commercial wine. The method uses the enzymes hexokinase, glucose-6-phosphate dehydrogenase, and phosphoglucose isomerase and the coenzyme nicotinamide-adenine dinucleotide phosphate. Both glucose and fructose can be determined in the same sample without separation. The method is simple but care is necessary to ensure precise transfer of small volumes. Repeatability and reproducibility standard deviations for glucose ranged from 2.6 to 14.6 mg/L and 4.7 to 16.5 mg/L, respectively. Repeatability and reproducibility values for fructose ranged from 2.4 to 16.1 mg/L and 6.0 to 21.3 mg/L, respectively. The method has been adopted official first action.

Fructose↗
PubMed2005

Comparison of extended field of view and dual image ultrasound techniques: accuracy and reliability of distance measurements in phantom study.

This study was undertaken to investigate and compare the accuracy and reliability of dual image and extended field-of-view (EFOV) ultrasound (US) techniques in distance measurements using acoustic phantoms. Ten tissue phantoms were constructed and were scanned twice with an interval of 3 days by two operators. Measurements of various known distance (ranging from 4.6 to 7.2 cm) in the phantoms were made with dual image and EFOV US. Results showed that both dual image and EFOV US have a high accuracy and reliability in distance measurements, with the EFOV US (r = 0.997 to 0.998, reproducibility = 99.8%, repeatability = 98.2 to 99.8%) being slightly more accurate and reliable than dual image US (r = 0.948 to 0.981, reproducibility = 94.6%, repeatability = 89.6 to 97.9%). EFOV US has a higher accuracy and reliability than dual image US in distance measurements. However, the dual image US is a useful alternative with a high accuracy and reliability when EFOV US is not available.

Data Display↗
PubMed2004

Computer image analysis for measuring lean and fatty areas in cross-sectioned dry-cured hams.

The aims of this study were 1) to apply computer image analysis to obtain measures of lean and fatty areas on the cross section of dry-cured hams, 2) to investigate variation of these measures, and 3) to evaluate reproducibility and repeatability of these techniques. Traits of concern were the cross-sectional area (SA), lean, or muscles, area (LA), and the fatty area (FA) centered on the cross section and surrounded by biceps femoris, semimembranosus, semitendinosus, and quadriceps femoris, as well as the FA-to-SA ratio (FESR). Hams were obtained from crossbred pigs (n = 279) slaughtered at 9 mo of age (mean BW of 169 +/- 17 kg). Digital images of the cross section of dry-cured hams were captured using standardized procedures. Three replicated measures of areas were collected by three operators using three image analysis techniques (automatic, automatic-assisted, and manual). Variance components were estimated using a linear model that included slaughter group, gender, and gender x slaughter group as fixed effects and operators, pig, and operator x pig as random effects. Statistical analyses considered all measures (n = 7,533) or measures collected after reinstruction of all operators for spatial calibration of the analysis system (n = 4,428). Average SA, LA, FA, and FESR were 350 cm2, 220 cm2, 8.7 cm2, and 2.5%, respectively. Variability of FA (CV = 42%) and of FESR (CV = 39%) was four times greater than that of SA and LA. Slaughter group, pig, operator, and operator x pig effects were the most (P < 0.01) important sources of variation of measures. Correlations between measures obtained with different techniques were greater (P < 0.01) than 0.90, with the exception of LA measures. Coefficients of reproducibility for SA and LA ranged from 87 to 94%, whereas those for FA and FESR ranged from 88 to 98%. Coefficients of repeatability ranged from 92 to 99%. Automatic-assisted and manual methods provided more reproducible and repeatable measures than the automatic technique. Spatial calibration of the software system was a key issue affecting reproducibility and repeatability. Reinstructing the analysts for spatial calibration enhanced both reproducibility and repeatability of all methods of analysis. Computer image analysis is a technique suitable for measuring lean and fatty areas in cross-sectioned hams, providing reproducible and repeatable measures, and it might be used in large sample-based studies to investigate causes of defective fatty areas.

Adipose Tissue↗
PubMed2000

Technique to measure lumbar curvature in the ergonomic evaluation of chairs: description and validation.

OBJECTIVE: To describe and validate a system to record the lumbar curvature, specially designed for the ergonomic evaluation of chairs. DESIGN: The technique consists of a flexible goniometer and requires a model of lumbar flexion (relationship between length and angle). BACKGROUND: Most of the techniques do not allow using the backrest of the chair or do not record continuously. METHODS: Precision, repeatability and reproducibility of the measurements have been analysed, as well as the lumbar flexion model. RESULTS: A suitable lumbar model of flexion and the repeatability and reproducibility errors obtained are presented. CONCLUSIONS: The linear model is a good one to represent the flexion of the lumbar spine. The measurements are reproducible and the errors are similar or lower than with conventional inclinometers. Relevance The device may help to investigate the relationship between lumbar pain and curvature, and to evaluate the lumbar curvature in sedentary work.

Analysis of Variance↗
PubMedDate not supplied

Determination of low-level glucose and fructose in raw and refined crystalline sugar by high-performance anion-exchange chromatography: collaborative study.

A method was developed and a collaborative study was performed under the auspices of the International Commission of Uniform Methods for Sugar Analysis. The collaborators used high-performance anion-exchange chromatography (HPAEC) to determine trace amounts of glucose and fructose in 3 raw and 3 refined sugar samples provided as blind duplicates. Fourteen laboratories participated in the study. Although difficulties were experienced by a few analysts, 10 laboratories reported positive results. Average repeatabilities and reproducibilities for glucose and fructose in raw sugar were slightly above 5 and 10%, respectively, and the average Horwitz ratios were well under 2. Average repeatabilities and reproducibilities for glucose and fructose in refined sugar were 10 and 22%, respectively; although the Horwitz ratios were >2, they were marginal (2.8). The HPAEC results agreed with results obtained by gas chromatography in an independent laboratory. Because the method was collaboratively studied according to the protocol of the International Union of Pure and Applied Chemistry for collaborative studies, and the results meet its criteria, it is recommended that the method be adopted Official First Action by AOAC INTERNATIONAL.

Calibration↗
PubMed2004

Detection of pathogenic micro-organisms--a contribution to discussion.

When applying methods for the detection of pathogenic micro-organisms in foodstuffs, information on the distribution of the target organism in the foodstuff submitted to a test should be available. The sampling plan used should allow to detect the presence of low levels of the target organism with a high probability. The individual steps of a detection procedure (pre-enrichment, selective enrichment, isolation and confirmation) need careful examination. It is important that inoculation of low levels of the target organism leads to successful enrichment even in the presence of relatively large numbers of competing organisms. In cases where competing micro-organisms form suspect colonies, there is a risk that false-negative results are obtained, because colonies of the target organism may not be isolated. Collaborative trials have to be carried out to assess the performance of presence/absence tests. Meaningful results are obtained only, if the test samples contain low levels of the target organism and if the effect of competing micro-organisms is checked. While it can hardly be disputed that the determination of the sensitivity and specificity of the test method provides valuable information, this cannot be said for "accordance" and "concordance", two recently proposed parameters which correspond to repeatability and reproducibility in quantitative tests. A better alternative may be to specify the probability to obtain two positive results, when analysing samples containing the target organism under repeatability or reproducibility conditions. In an analogous way, the probability to obtain two negative results with samples containing competing micro-organisms, but not the target organism, could be specified.

Bacteria↗
PubMed2000

Static stabilometry and repeated testing in a normal population.

BACKGROUND: The purpose of the present study was to see if there is a learning effect of repeated static stabilometric testing, using a protocol suitable for testing postural control in narrow spaces, like hypo- and hyperbaric chambers. HYPOTHESIS: Static stabilometry testing under normobaric conditions is objective and reproducible. With repeated testing, a learning effect may be observed. METHODS: Four groups of healthy individuals were tested ten times under the same four acoustically and visually standardized and normobaric normoxic test conditions on a static balance platform. First, the subjects were asked to stand on a bare platform with the eyes open, thereafter with the eyes closed. This was repeated with a foam rubber mat placed on top of the balance platform. The time interval between the first and the last test sequence was 11 (10-13) days for the test subjects in group I (n = 22), 17 d for group II (n = 13), 31(28-36) days for group III (n = 15) and 115 (49-193) days for group IV (n = 10). RESULTS: Static stabilometry tests in a normal population are objective and reproducible. With repeated tests, a learning effect was observed. The learning effect was largest when standing on a foam rubber mat with eyes closed and when the time intervals between the tests were shortest. There was no difference in sway pattern or learning ability between tall and short test subjects, between subjects with heavy and light body weight or between the sexes.

Adult↗
PubMedDate not supplied

Accuracy of acetabular component positioning with a fluoroscopically referenced CAOS system.

OBJECTIVE: This study evaluated the accuracy, repeatability, and reproducibility of a fluoroscopic referenced system used for guiding acetabular component positioning. METHODS: Calibration of the Medtronic StealthStation Treon Plus system was performed using a Weber gage block to assess linearity. Metrologic validation of repeatability and reproducibility was done using a cadaveric pelvis with an uncemented cup placed in the target position of 45 degrees inclination and 17.5 degrees anteversion. A baseline assessment was done with a National Institute of Standards and Technology (NIST) traceable coordinate measuring machine (CMM). RESULTS: Weber gage block analysis revealed a mean bias of 0.69 mm. For the cadaveric pelvis, the anterior pelvic plane was determined using the bilateral anterior superior iliac spines with the symphysis pubis as the inferior landmark. The mean CMM measurement was inclination of 46.023 degrees (SD=1.075; range: 43.318-46.844 degrees) and anteversion of 15.787 degrees (SD=0.411; range: 15.068-16.384 degrees). One surgeon performed a repeatability assessment (n=8), finding mean inclination of 42.8 degrees (SD=1.5; range: 39.5-44.5 degrees) and anteversion of 17.5 degrees (SD=3.0; range: 14.5-22.5 degrees). Three surgeons performed a reproducibility assessment (n=24), finding mean overall inclination of 48.5 degrees (SD=0.9; range: 46-50 degrees) and anteversion of 17.8 degrees (SD=2.5; range: 13.5-23.5 degrees). All measurements were within a predefined acceptability range of+/-5 degrees. DISCUSSION: The accuracy and reproducibility of the fluoroscopic referencing method was found to be suitable for determination of cup position in the surgical setting. Anteversion measurements were more variable for the fluoroscopic method and this may be related to the difficulty for the surgeon in predictably picking the anatomical points from the fluoroscopic image.

Acetabulum↗
PubMed1982

Collaborative evaluation of rolling ball viscometer for measuring somatic cells in abnormal milk.

The Ruakura rolling ball viscometer was evaluated in 3 laboratories along with currently approved instrumental methods for measuring somatic cells in milk and the Wisconsin mastitis test. Replacement of the Teepol reagent with Wisconsin mastitis test reagent in the rolling ball viscometer was also evaluated. Both repeatability and reproducibility were satisfactory for all methods evaluated. The instrumental methods each gave higher readings than the other 3 methods. Use of Wisconsin mastitis test reagent in the rolling ball viscometer improved both repeatability and reproducibility. Additional work on standardization is suggested to match rolling ball viscometer readings with those of the instrumental methods.

Animals↗
PubMedDate not supplied

Liquid chromatographic determination of penicillin V potassium in tablets: collaborative study.

A liquid chromatographic method for the determination of penicillin V potassium in tablets was collaboratively studied by 7 laboratories. The method uses an octadecyl silane reverse-phase column, a mobile phase of acetonitrile-methanol-0.01 M potassium phosphate monobasic (21 + 4 + 75 v/v/v), photometric detection at 225 nm, and sulfadimethoxine as an internal standard. Each collaborator received 6 samples: powdered composites of 2 commercial tablet preparations and 1 synthetic tablet powder mixture, each with blind duplicates. The mean repeatability and reproducibility relative standard deviations for commercial samples were, respectively, 1.10 and 1.46% (250 mg dosage), and 0.84 and 2.82% (500 mg dosage). The average standard recovery from the synthetic formulation was 99.1%, with repeatability and reproducibility relative standard deviations of 1.30 and 3.66%, respectively. The method has been adopted official first action.

Chromatography, Liquid↗
PubMed1979

Collaborative study of a GLC method for vitamin E.

The official GLC method of the Association of Official Analytical Chemists (AOAC) for determining vitamin E was modified and collaboratively studied for the National Formulary (NF). The internal standard hexadecyl hexadecanoate (cetyl palmitate) was substituted for the dotriacontane used in the AOAC method, and some other minor changes were made. Eleven samples, representing all types of NF formulations and NF bulk materials, were analyzed by 11 laboratories. The coefficients of variation of the reproducibility and repeatability were 4.5 and 2.4%, respectively, for all laboratories and samples. The values were 3.4 and 1.6%, respectively, when the one laboratory statistically determined to be an outlier was excluded. The coefficients of variation of reproducibility and repeatability for alpha-tocopheryl acid succinate were 2.1 and 1.5%, respectively. All of these values lie within the 5% limit required by the NF.

Analysis of Variance↗
PubMedDate not supplied

Determination of ethanol in wine by titrimetric and spectrophotometric dichromate methods: collaborative study.

A dichromate-spectrophotometric method for the determination of ethanol in wine was compared in a collaborative, matched pair study with the AOAC dichromate-titrimetric method, 11.008-11.011. Both methods require distillation of the sample into dichromate. The titrimetric method measures ethanol by titrating the excess dichromate with ferrous ammonium sulfate after conversion of ethanol to acetic acid; the spectrophotometric method directly measures the reduced dichromate formed after oxidation. In addition to comparing the 2 methods, the collaborative study also compared the use of 2 types of assemblies for obtaining the ethanol distillate: the Scott-type, which is used in 11.008-11.011, and the electric Kirk-type. Results of the collaborative study indicated that the repeatability and reproducibility of the official titrimetric method were generally far superior to those of the spectrophotometric method; therefore, adoption of the spectrophotometric method is not recommended. Comparison of titrimetric method results obtained using the 2 types of stills indicated that repeatability and reproducibility were somewhat better when Scott apparatus was used, but measurements using Kirk-type compared well in the range of ethanol concentrations found in table and fortified wines. The Kirk-type distillation apparatus has been adopted official first action as an alternative to Scott apparatus in the dichromate oxidation method for ethanol in wine, 11.008-11.011.

Chromates↗
PubMed2006

Doppler myocardial imaging in adult male rats: reference values and reproducibility of velocity and deformation parameters.

AIM: Limited data are available about the use of Doppler myocardial imaging (DMI) in small animals. We intend to provide reference values for velocity, strain and strain rate in a large group of healthy rats and studied the reproducibility and repeatability of these parameters. METHODS AND RESULTS: A total of 33 male Wistar rats (503+/-41g) underwent baseline transthoracic echocardiography with DMI of the anterior and inferior wall in a short-axis view using a 13MHz linear probe. Adequate tissue Doppler measurements could be obtained in 30 rats. On average 10+/-4 consecutive cycles were studied in post-processing using dedicated software (SPEQLE). Mean radial peak systolic velocity, strain and strain rate were respectively -0.8+/-0.3cm/s, 38+/-8% and 9.1+/-2.0/s in the anterior wall and 3.1+/-0.6cm/s, 49+/-10% and 13.7+/-3.7/s in the inferior wall. The reproducibility and repeatability of the DMI measurements assessed in 10 rats was good. CONCLUSION: DMI is feasible and reproducible in healthy rats. Establishing reference values opens new perspectives towards the use of strain and strain rate imaging in small rodents in the assessment of myocardial diseases.

Animals↗