Proficiency Samples for Quality Assurance in Trichinella Digestion Tests

1998 ◽  
Vol 61 (10) ◽  
pp. 1396-1399 ◽  
Author(s):  
LORRY B. FORBES ◽  
ANDRIJANA RAJIC ◽  
ALVIN A. GAJADHAR
Keyword(s):  
Quality Assurance ◽  
Trichinella Spiralis ◽  
Prior Experience ◽  
Sample Weight ◽  
Validation Data ◽  
Sample Matrix ◽  
Proficiency Panel ◽  
Agar Substrate ◽  
The Mean ◽  
Larval Recovery

A reliable method to produce proficiency samples containing known numbers of Trichinella spiralis cysts for use in quality assurance systems for Trichinella digestion tests was developed and validated. A filtrate containing Trichinella cysts was produced by homogenizing and filtering the muscles of an experimentally infected rat. Using a stereomicroscope and micropipette, intact cysts were removed from the filtrate and were transferred onto an agar substrate to allow accurate counting and subsequent transfer into a sample matrix. The proficiency sample matrix consisted of 20-g balls of lean ground beef and was combined with 80 g of a Trichinella-free muscle tissue to obtain the required 100-g sample weight for the assay. The mean overall larval recovery from 404 proficiency samples was 93.0%. Larval recoveries ≥95, 85, and 75% occurred in 52.4, 84.4, and 94.3%, respectively, of the 404 samples tested. Results indicated that, after a short training period, technicians with no prior experience in digestion techniques performed as well as experienced technicians. The maximum shelf life of proficiency samples was not determined but was at least 3 weeks. Validation data were used to develop panels composed of proficiency samples prepared as described above and to establish guidelines for the interpretation of proficiency panel results.

A Nonspecific Learning Effect in the Perception of Random-Dot Stereograms?

Perception ◽  
1982 ◽  
Vol 11 (1) ◽  
pp. 93-95 ◽  
Author(s):  
John Weinman ◽  
Vicky Cooke
Keyword(s):  
Learning Effect ◽  
Prior Experience ◽  
Naive Group ◽  
Random Dot Stereograms ◽  
Perception Time ◽  
The Mean

An experiment is reported the object of which was to check whether a small amount of nonspecific experience in perceiving random-dot stereograms could facilitate the perception of a previously unseen stereogram. The mean stereopsis perception time of a group of totally naive subjects was found to be significantly slower than that of a group who had previously been shown two different stereograms. Closer inspection of the data showed that this difference was primarily due to approximately one third of the naive group who were much slower than the ‘experienced’ group. It is therefore suggested that nonspecific experience provides most initial help for relatively slow perceivers, since many naive subjects can perform as well as those with prior experience of other stereograms.

scholarly journals The reproducibility of subjective appetite scores

1995 ◽  
Vol 73 (4) ◽  
pp. 517-530 ◽  
Author(s):  
Anne Raben ◽  
ANNA TAGLIABUE ◽  
Arne Astrup
Keyword(s):  
Visual Analogue Scale ◽  
Food Consumption ◽  
Analogue Scale ◽  
Prior Experience ◽  
Random Noise ◽  
Normal Weight ◽  
Vas Scores ◽  
The Mean ◽  
The Difference ◽  
Mean Differences

Although subjective appetite scores are widely used, studies on the reproducibility of this method are scarce. In the present study nine healthy, normal weight, young men recorded their subjective appetite sensations before and during 5 h after two different test meals A and B. The subjects tested each meal twice and in randomized order. Visual analogue scale (VAS) scores, 10 cm in length, were used to assess hunger, satiety, fullness, prospective food consumption and palatability of the meals. Plasma glucose and lactate concentrations were determined concomitantly. The repeatability was investigated for fasting values, Δ-mean 5 h and mean 5 h values, Δ-peak/nadir and peak/nadir values. Although the profiles of the postprandial responses were similar, the coefficients of repeatability (CR = 2SD) on the mean differences were large, ranging from 2·86 to 5.24 cm for fasting scores, 1·36 to 1·88 cm for mean scores, 2·98 to 5·42 cm for Δ-mean scores, and 3·16 to 6·44 cm for peak and Δ-peak scores. For palatability ratings the CK values varied more, ranging from 2·38 (taste) to 8·70 cm (aftertaste). Part of the difference in satiety ratings could be explained by the differences in palatability ratings. However, the low reproducibility may also be caused by a conditioned satiation or hunger due to the subjects' prior experience of the meals and therefore not just be a reflection of random noise. It is likely, however, that the variation in appetite ratings is due both to methodological day-to-day variation and to biological day-to-day variation in subjective appetite sensations.

scholarly journals Ground-based Measurements of Atmospheric Trace Gases in Beijing during the Olympic Games

Sci ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 6
Author(s):  
Jie Cheng
Keyword(s):  
Olympic Games ◽  
Trace Gases ◽  
Fourier Transform Spectrometer ◽  
Atmospheric Trace Gases ◽  
Validation Data ◽  
Solar Absorption ◽  
The Mean ◽  
The City ◽  
Total Column ◽  
The Olympic Games

A portable Fourier Transform Spectrometer (B3M-IR) is built and used to measure atmospheric trace gases in the city of Beijing during Olympic Games in 2008. A short description of the instrument is first provided in this paper. A detailed spectral analysis is then presented. The total columns of ozone (O3), carbon monoxide (CO), methane (CH4) and nitrous oxide (N2O) are retrieved from the ground-based solar absorption spectra recorded by the B3M-IR during the Olympic Games. Lacking validation data, only the retrieved total column of O3 is compared with that retrieved by MAX-DOAS, which is deployed at the same station. The mean difference between the two methods of measurement is 6.5%, demonstrating the performance and reliability of B3M-IR.

Glycohaemoglobin: Comparison of 12 Analytical Methods, Applied to Lyophilized Haemolysates by 101 Laboratories in an External Quality Assurance Programme

1993 ◽  
Vol 30 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Cas W Weykamp ◽  
Theo J Penders ◽  
Frits A J Muskiet ◽  
Willem van der Slik
Keyword(s):  
Quality Assurance ◽  
Acetic Acid ◽  
Coefficient Of Variation ◽  
External Quality Assurance ◽  
External Quality ◽  
Quality Assurance Programme ◽  
Coefficients Of Variation ◽  
Two Samples ◽  
The Mean ◽  
Edta Blood

Stable lyophilized ethylenediaminetetra-acetic acid (EDTA)-blood haemolysates were applied in an external quality assurance programme (SKZL, The Netherlands) for glycohaemoglobin assays in 101 laboratories using 12 methods. The mean intralaboratory day-to-day coefficient of variation (CV), calculated from the assay of 12 unidentified pairs over a period of 1 year, was 5·2% (range: 0·2–28·7). Forty-seven per cent of laboratories did not meet the criterion of CV < 5%, whereas 68% did not meet the clinically more desirable 3·3–3·6%. Linearity, as derived from the analysis of five combinations of two haemolysates with low and high glycohaemoglobin percentages over 6 months, was excellent (mean correlation coefficient 0·9953; range: 0·9188–0·9999). Analysis of two samples with high and low glycohaemoglobin percentages gave mean interlaboratory coefficients of variation of 10% for one method performed by several laboratories and 22% for all methods performed by all laboratories. It is concluded that the majority of laboratories do not meet the clinically desirable intralaboratory precision and that an unacceptably high interlaboratory precision exists.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

scholarly journals Regional gravity field refinement for (quasi-) geoid determination based on spherical radial basis functions in Colorado

2020 ◽  
Vol 94 (10) ◽  
Author(s):  
Qing Liu ◽  
Michael Schmidt ◽  
Laura Sánchez ◽  
Martin Willberg
Keyword(s):  
Gravity Data ◽  
Basis Functions ◽  
Height Anomaly ◽  
Shannon Function ◽  
Validation Data ◽  
Topographic Model ◽  
Spherical Radial Basis Functions ◽  
The Mean ◽  
Rms Error ◽  
Terrestrial Data

Abstract This study presents a solution of the ‘1 cm Geoid Experiment’ (Colorado Experiment) using spherical radial basis functions (SRBFs). As the only group using SRBFs among the fourteen participated institutions from all over the world, we highlight the methodology of SRBFs in this paper. Detailed explanations are given regarding the settings of the four most important factors that influence the performance of SRBFs in gravity field modeling, namely (1) the choosing bandwidth, (2) the locations of the SRBFs, (3) the type of the SRBFs as well as (4) the extensions of the data zone for reducing the edge effect. Two types of basis functions covering the same spectral range are used for the terrestrial and the airborne measurements, respectively. The non-smoothing Shannon function is applied to the terrestrial data to avoid the loss of spectral information. The cubic polynomial (CuP) function which has smoothing features is applied to the airborne data as a low-pass filter for filtering the high-frequency noise. Although the idea of combining different SRBFs for different observations was proven in theory to be possible, it is applied to real data for the first time, in this study. The RMS error of our height anomaly result along the GSVS17 benchmarks w.r.t the validation data (which is the mean results of the other contributions in the ‘Colorado Experiment’) drops by 5% when combining the Shannon function for the terrestrial data and the CuP function for the airborne data, compared to those obtained by using the Shannon function for both the two data sets. This improvement indicates the validity and benefits of using different SRBFs for different observation types. Global gravity model (GGM), topographic model, the terrestrial gravity data, as well as the airborne gravity data are combined, and the contribution of each data set to the final solution is discussed. By adding the terrestrial data to the GGM and the topographic model, the RMS error of the height anomaly result w.r.t the validation data drops from 4 to 1.8 cm, and it is further reduced to 1 cm by including the airborne data. Comparisons with the mean results of all the contributions show that our height anomaly and geoid height solutions at the GSVS17 benchmarks have an RMS error of 1.0 cm and 1.3 cm, respectively; and our height anomaly results give an RMS value of 1.6 cm in the whole study area, which are all the smallest among the participants.

scholarly journals Validation and update of OMI Total Column Water Vapor product

2016 ◽  
Vol 16 (17) ◽  
pp. 11379-11393 ◽  
Author(s):  
Huiqun Wang ◽  
Gonzalo Gonzalez Abad ◽  
Xiong Liu ◽  
Kelly Chance
Keyword(s):  
Water Vapor ◽  
Liquid Water ◽  
Retrieval Algorithm ◽  
Ozone Monitoring Instrument ◽  
Validation Data ◽  
Data Set ◽  
Wide Range ◽  
Key Factor ◽  
The Mean ◽  
Total Column

Abstract. The collection 3 Ozone Monitoring Instrument (OMI) Total Column Water Vapor (TCWV) data generated by the Smithsonian Astrophysical Observatory's (SAO) algorithm version 1.0 and archived at the Aura Validation Data Center (AVDC) are compared with NCAR's ground-based GPS data, AERONET's sun-photometer data, and Remote Sensing System's (RSS) SSMIS data. Results show that the OMI data track the seasonal and interannual variability of TCWV for a wide range of climate regimes. During the period from 2005 to 2009, the mean OMI−GPS over land is −0.3 mm and the mean OMI−AERONET over land is 0 mm. For July 2005, the mean OMI−SSMIS over the ocean is −4.3 mm. The better agreement over land than over the ocean is corroborated by the smaller fitting residuals over land and suggests that liquid water is a key factor for the fitting quality over the ocean in the version 1.0 retrieval algorithm. We find that the influence of liquid water is reduced using a shorter optimized retrieval window of 427.7–465 nm. As a result, the TCWV retrieved with the new algorithm increases significantly over the ocean and only slightly over land. We have also made several updates to the air mass factor (AMF) calculation. The updated version 2.1 retrieval algorithm improves the land/ocean consistency and the overall quality of the OMI TCWV data set. The version 2.1 OMI data largely eliminate the low bias of the version 1.0 OMI data over the ocean and are 1.5 mm higher than RSS's “clear” sky SSMIS data in July 2005. Over the ocean, the mean of version 2.1 OMI−GlobVapour is 1 mm for July 2005 and 0 mm for January 2005. Over land, the version 2.1 OMI data are about 1 mm higher than GlobVapour when TCWV  <  15 mm and about 1 mm lower when TCWV  >  15 mm.

scholarly journals Patient-Specific Quality Assurance Using a 3D-Printed Chest Phantom for Intraoperative Radiotherapy in Breast Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Yeonho Choi ◽  
Ik Jae Lee ◽  
Kwangwoo Park ◽  
Kyung Ran Park ◽  
Yeona Cho ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Soft Tissue ◽  
Three Dimensional ◽  
Intraoperative Radiotherapy ◽  
Hounsfield Unit ◽  
Patient Specific ◽  
Depth Dose ◽  
Dose Comparison ◽  
3D Printed ◽  
The Mean

This study aims to confirm the usefulness of patient-specific quality assurance (PSQA) using three-dimensional (3D)-printed phantoms in ensuring the stability of IORT and the precision of the treatment administered. In this study, five patient-specific chest phantoms were fabricated using a 3D printer such that they were dosimetrically equivalent to the chests of actual patients in terms of organ density and shape around the given target, where a spherical applicator was inserted for breast IORT treatment via the INTRABEAM™ system. Models of lungs and soft tissue were fabricated by applying infill ratios corresponding to the mean Hounsfield unit (HU) values calculated from CT scans of the patients. The two models were then assembled into one. A 3D-printed water-equivalent phantom was also fabricated to verify the vendor-provided depth dose curve. Pieces of an EBT3 film were inserted into the 3D-printed customized phantoms to measure the doses. A 10 Gy prescription dose based on the surface of the spherical applicator was delivered and measured through EBT3 films parallel and perpendicular to the axis of the beam. The shapes of the phantoms, CT values, and absorbed doses were compared between the expected and printed ones. The morphological agreement among the five patient-specific 3D chest phantoms was assessed. The mean differences in terms of HU between the patients and the phantoms was 2.2 HU for soft tissue and −26.2 HU for the lungs. The dose irradiated on the surface of the spherical applicator yielded a percent error of −2.16% ± 3.91% between the measured and prescribed doses. In a depth dose comparison using a 3D-printed water phantom, the uncertainty in the measurements based on the EBT3 film decreased as the depth increased beyond 5 mm, and a good agreement in terms of the absolute dose was noted between the EBT3 film and the vendor data. These results demonstrate the applicability of the 3D-printed chest phantom for PSQA in breast IORT. This enhanced precision offers new opportunities for advancements in IORT.

Quality Assurance in the Analysis of Foods for Trace Constituents

1980 ◽  
Vol 63 (6) ◽  
pp. 1344-1354 ◽  
Author(s):  
William Horwitz ◽  
La Verne R Kamps ◽  
Kenneth W Boyer
Keyword(s):  
Quality Assurance ◽  
Coefficient Of Variation ◽  
Toxic Elements ◽  
Collaborative Studies ◽  
Powers Of 2 ◽  
Analytical Work ◽  
Independent Replication ◽  
The Mean ◽  
Trace Constituents ◽  
Mean Concentration

Abstract An examination of the results of over 50 interlaboratory collaborative studies conducted by the AOAC on various commodities for numerous analytes shows a relationship between the mean coefficient of variation (CV), expressed as powers of 2, with the mean concentration measured, expressed as powers of 10, independent of the determinative method. Some typical CV values are: drug formulations at a 1% concentration, 2%; sulfonamides in feeds at a 0.01% concentration, 4%; pesticide residues and toxic elements, 10 6 (1 ppm), 16%; and aflatoxins 10 8 (10 ppb), 32%. Analytical work at trace levels must be constantly monitored through analysis of reference materials and surrogate samples, and by independent replication.

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