Maximum Acceptable Difference Research Articles

Suitability of Inguinal and Axillary Sites for Temperature Measurement Using Digital Thermometers: A Comparison with Rectal Thermometry in Broiler Chickens

Core body temperature is one of the physiological parameters that must be assessed during the monitoring of the thermic and or health status of broiler chickens. In this regard, cloacal thermometry is a standard method used for temperature measurement although it has many drawbacks. This study was conducted to explore the suitability of other anatomical sites for temperature measurement using a digital thermometer. This was a single-factor experiment that considered the anatomical site as the main factor with three levels (treatments), including cloacal (DTtcloacal), axillary (DTtaxillary), and inguinal (DTtinguinal) sites. Out of 84 broiler chickens, a total of 28 chickens were randomly selected for temperature measurement. The temperature was measured for each anatomical site, and the readings were analyzed using appropriate statistics. The cloacal site had the highest mean temperature (41.40 ± 0.17℃), while the lowest mean value was observed for the axillary site (41.12 ± 0.19℃). There was no significant difference between the mean cloacal and inguinal temperatures. The cloacal and inguinal temperature readings were significantly correlated. The results for the cloacal and inguinal temperature measurements revealed a non-significant bias. The agreement interval between these two methods was sufficiently lower than the maximum acceptable difference between the anatomical sites. Both cloacal and inguinal temperature measurements had similar median points. The results indicated an underestimation of the temperature readings for the axillary site compared to those of the other sites. In conclusion, this study has revealed that the application of a digital thermometer using the inguinal site gives temperature readings that are similar to those of the conventional cloacal method.

Agreement between VO2max estimated from six-minute walk test and Chester step test in normal adults

Background: Cardiorespiratory fitness is a health-related component of overall physical fitness assessed as maximal oxygen uptake (VO2max) during any physical activity. The six-minute walk test (6MWT) and Chester step test (CST) are two submaximal exercise tests routinely administered to estimate the VO2max of an individual. Thus, the aim of this study was to assess whether an agreement exists between the VO2max estimated by 6MWT and CST in normal adults. Method: This crossover study was conducted with 80 healthy adults aged 18-40 years. All participants performed the 6MWT and CST on consecutive days. VO2max from the 6MWTwas estimated using a prediction equation whereas from the CST using the graphical plot method. Results: The mean VO2max-6MWT and VO2max-CST were 43.53 ± 4.65 ml/kg/min and 38.34 ± 4.94 ml/kg/min respectively. The Bland and Altman analysis revealed that the mean difference between VO2max-6MWT and VO2max-CST was 5.19 ± 5.50 ml/kg/min which exceeded the maximum acceptable difference of 3 ml/kg/min decided a priori. The line of equality (X axis) did not fall within the confidence interval of the mean difference indicating that VO2max estimated using the two submaximal exercise tests significantly differ from each other. The standard error of mean was 0.61 ml/kg/min and the standard error of limits of agreement was 1.06 ml/kg/min. Conclusion: VO2max estimated from the six-minute walk test and Chester step test show no agreement with each other.

Expanding the color gamut of inkjet textile printing during color matching

AbstractOne of the most important subjects of digital printing is evaluation of color gamut mapping. A printer can only reproduce colors that are in its color gamut. Maybe, a color tolerance between reference sample and printed sample is in agreement between manufacturer and customer. The goal of this work is to estimate the expansion of the color gamut of an inkjet textile printer by consideration of the acceptable (predetermined) color difference during color matching. For analyzing the color gamut, a standard color chart IT8.7/4‐2005 CMYK target was printed by nine different mixtures of CMYK, and then the reflectance spectra and colorimetric parameters of the printed samples were measured. The inks used were disperse water‐based inks that were printed on the polyester fabric. The maximum acceptable color difference in this study was equal to 2 CIELAB units for all colors. In order to estimate the color gamut with the maximum acceptable color difference, for all boundary points of gamut, expanded points were obtained by Euclidean distance less than = 2. The results show that when the acceptable color difference is considered in color gamut measuring, the area and volume of the color gamut are increased and so, the reproducibility of printer is increased. The maximum and minimum expansions of color gamut volumes were obtained by the mixtures with minimum and maximum color gamuts, respectively. The volume expansion of the mixture with the minimum color gamut volume was 34.20%, while the volume expansion of the mixture with the maximum color gamut volume was 28.06%.

A Pilot Study of the Reliability and Agreement of Heart Rate, Respiratory Rate and Short-Term Heart Rate Variability in Elite Modern Pentathlon Athletes.

Research on reliability of heart rate variability (HRV) parameters in athletes has received increasing attention. The aims of this study were to examine the inter-day reliability of short-term (5 min) and ultra-short-term (1 min) heart rate (HR), respiratory rate (RespRate) and HRV parameters, agreement between short-term and ultra-short-term parameters, and association between differences in HR, RespRate and HRV parameters in elite modern pentathletes. Electrocardiographic recordings were performed in stable measurement conditions with a week interval between tests. Relative reliability was evaluated by intra-class correlation coefficients, absolute reliability was evaluated by within-subject coefficient of variation, and agreement was evaluated using Bland–Altman (BA) plot with limits of agreement and defined a priori maximum acceptable difference. Short-term HR, RespRate, log transformed (ln) root mean square of successive normal-to-normal interval differences (lnRMSSD), ln high frequency (lnHF) and SD2/SD1 HRV indices and ultra-short-term HR, RespRate and lnRMSSD presented acceptable, satisfactory inter-day reliability. Although there were no significant differences between short-term and ultra-short-term HR, RespRate and lnRMSSD, no parameter showed acceptable differences with BA plots. Differences in time-domain and non-linear HRV parameters were more correlated with differences in HR than with differences in RespRate. Inverse results were observed for frequency-domain parameters. Short-term HR, RespRate, lnRMSSD, lnHF, and SD2/SD1 and ultra-short-term HR, RespRate and lnRMSSD could be used as reliable parameters in endurance athletes. However, practitioners should interpret changes in HRV parameters with regard to concomitant differences in HR and RespRate and caution should be taken before considering 5 min and 1 min parameters as interchangeable.

Comparation of three methods for measuring the Edge Bevel Radius of rectangular orthodontic wires: An in-vitro study

To establish a simplified method for measuring the edge bevel radius of 0.019×0.025-in steel rectangular orthodontic wires, achievable in the clinical environment, and to compare it with the photographic method. Aided by the AutoCAD™ 2016 software, the theoretical mathematical relationship was determined between the edge rounding radius and cross-sectional dimensions (height, width, diagonals), through rectangle drawings that represent cross-sections. Two hundred segments (n=20) were obtained from the posterior portions of 100 archwires from 10 brands (Dentaurum™; American-Orthodontics™; GAC™; 3M-Unitek™; Abzil™; Morelli™; Orthometric™; Aditek™; A-Company™; Orthomundi™). The cross-sectional measures of each segment were obtained with a micrometer and a caliper, and the edge bevel radii of these segments were calculated with the use of a mathematical formula. For the "gold standard", the segments were included longitudinally in a phenolic resin cylinder, cross-sectioned, polished, and photographed in scanning electron microscope (SEM). The images were amplified 770× and the radii were measured with an acetate template. The micrometer and caliper measuring methods were subjected to Bland-Altman analysis and compared with the gold standard (SEM), considering ±10μm as the maximum acceptable difference between methods. In the micrometre measurement, 95% of the differences from the standard were within the limits of agreement (-7.21 and 5.56μm). For the caliper method, 95% of the differences were between -5.46 and 19.83μm, which exceeded the fixed limit ±10μm. The calculation method with micrometre measurements is equivalent to the photographic method, but there is no such equivalence for the caliper measurements.

Comparing the Accuracy of Physiologic and Triangular Pseudoflow Waveforms for Estimating Wave Reflection Indices in Adults

Central aortic pressure waveforms contain valuable prognostic information in addition to central systolic pressure. Using wave separation analysis, aortic pressure‐flow relations can be used to decompose aortic pressure waveforms into forward (Pf) and backward‐travelling (Pb) components. Pf and Pb are used to calculate reflection magnitude (RM=Pb/Pf) which is predictive of heart failure and all‐cause mortality. Aortic blood flow can be measured non‐invasively via ultrasonography or estimated using a triangular pseudoflow waveform; however, the latter can underestimate true flow and thus overestimate Pb and RM. Recently, a physiologic pseudoflow waveform has been developed that improves on the assumptions of triangulation and so may provide a more accurate estimation of wave reflection.PURPOSEThe purpose of this study was to compare estimates of Pf, Pb, and RM derived from physiologic and triangular pseudoflow waveforms relative to measured flow. We hypothesized that the physiologic waveform would provide a more accurate estimate of wave reflection indices compared to the triangular waveform.METHODSIn 75 adults (age 18–75 yrs), radial artery pressure waveforms were acquired with applanation tonometry and a generalized transfer function was used to synthesize central pressure waveforms. Aortic blood flow velocities were measured via echocardiography and estimated using physiologic (in‐house software) and triangular (SphygmoCor CvMS) pseudoflow waveforms. Pressure‐flow relations were established offline and wave separation analysis was performed. Accuracy of the physiologic and triangular‐derived estimates of Pf, Pb, and RM were assessed using 95% equivalence testing, paired t‐tests comparing the mean absolute biases, and Bland‐Altman plots.RESULTSUsing a 10% equivalence zone as the maximum acceptable difference, the physiologic and triangular pseudoflow waveforms were both comparable to the measured flow waveform in deriving Pf. However, only the physiologic waveform yielded similar estimates of Pb and RM compared to the measured waveform. Further, the physiologic waveform yielded lower mean absolute biases compared to the triangular waveform for Pf (1.7 ± 2.1 vs. 2.8 ± 2.6 mmHg, p<0.001), Pb (1.0 ± 1.1 vs. 3.3 ± 2.7 mmHg, p<0.001), and RM (3 ± 3 vs. 14 ± 13%, p<0.001). Lastly, Bland‐Altman biases were smaller, and 95% limits of agreement were narrower, for all wave reflection indices derived from the physiologic waveform than from the triangular waveform.CONCLUSIONThese data suggest that the physiologic pseudoflow waveform provides a more accurate estimate of wave reflection indices compared to the triangular waveform, and thus may offer a superior alternative when true flow cannot be measured.

Steady state operation exergy‐based optimization for solar thermal collectors

AbstractIn this investigation, exergy‐based optimization was carried out on two configurations of solar thermal collectors. A set of control sensors were utilized to control the performance of the system and monitor the design variables, that is, inlet and outlet temperature of the solar fluid, ambient temperature, incident solar flux, and required mechanical and electrical work in the system. The fluid temperature was considered to vary in the range of 120–180°C with respect to technical and economic considerations. The collector surface area was considered 606 m2 in both configurations, and a medium solar incident was considered about 520 W/m2. The maximum acceptable temperature difference is obtained as function of the input temperature. The technical limitation is plotted for both configurations of solar collectors. It was noticed that the exergy flow of simple evacuated tubes can reach the maximum value when the input temperature is greater than 115°C for an incident solar flow, from 250 W/m2 up to the limit of 950 W/m2. Exergy analysis demonstrated that more control is required on the temperature control to obtain the optimum performance of the solar collector. Thus, applying exergy optimization approach can be very useful to guide control system, the maximum outlet temperature being a key variable on the performance of the collectors.

Assessing agreement with relative area under the coverage probability curve.

There has been substantial statistical literature in the last several decades on assessing agreement, and coverage probability approach was selected as a preferred index for assessing and improving measurement agreement in a core laboratory setting. With this approach, a satisfactory agreement is based on pre-specified high satisfactory coverage probability (e.g., 95%), given one pre-specified acceptable difference. In practice, we may want to have quality control on more than one pre-specified differences, or we may simply want to summarize the agreement based on differences up to a maximum acceptable difference. We propose to assess agreement via the coverage probability curve that provides a full spectrum of measurement error at various differences/disagreement. Relative area under the coverage probability curve is proposed for the summary of overall agreement, and this new summary index can be used for comparison of different intra-methods or inter-methods/labs/observers' agreement. Simulation studies and a blood pressure example are used for illustration of the methodology. Copyright © 2016 John Wiley & Sons, Ltd.

Modelling CO2-brine-rock interactions in the Upper Paleozoic formations of Ordos Basin used for CO2 sequestration

Subsurface immobilization and conversion of CO2 into solid mineral phases in deep siliciclastic saline formations containing silicate minerals, commonly known as “mineral trapping”, is gaining research attention as a significant option to reduce CO2 emissions in the atmosphere. Although mineral trapping of CO2 is a long-term process, a combination of short-term results from both laboratory experiments and numerical simulations can lead to some general understanding of the required long-term CO2 sequestration mechanisms. This is a 100 year preliminary batch simulation study of four sandstone samples, under CO2 saturated water at 75 °C from the Upper Permian formations in the Ordos Basin, using the TOUGHREACT/ECO2N module to simulate the CO2-brine-rock interaction processes in deep siliciclastic multilayered saline aquifers. The samples approximately correspond to the four target saline formations selected by the Shenhua Group for a CO2 sequestration field demonstration project in the Ordos Basin, PR China. Preliminary simulation results show that the initial salinity of formation brine plays a significant role in determining the amount of CO2 that will be sequestered by solubility or mineral trapping in a deep saline aquifer. Minimal differences between experimental results and numerical calculation occur in low salinity waters, and significantly larger differences in high salinity waters, which is still under the maximum acceptable difference between experimental and computed data (10 %). The upper Liujiagou formation, with the highest level of salinity (ca. 88.7 g/L TDS) and lowest level of CO2 solubility, offers the highest mineral trapping capacity, with a maximum carbonate mineral storage of ca. 0.7 kg/m3 of bulk rock over a 100 year period. Regardless of the initial acidity or alkalinity of the aquifer brine, injection of CO2 will inflict a sudden drop in pH of the brine to acidity levels in a range of 3.0–4.6. The subsequent amount of dissolved and precipitated minerals, arising from the CO2-brine-rock interaction, is site specific and mainly dependent on initial aquifer mineralogy and brine composition.

Direct and indirect comparison of the efficacy and safety of adalimumab, etanercept, infliximab and golimumab in psoriatic arthritis

Psoriatic arthritis is an autoimmune disease characterized by chronic inflammation of the skin and joints. Anti-TNF drugs reduce the severity of the disease in the long term. This study compares the efficacy and safety of adalimumab, etanercept, infliximab and golimumab in patients with psoriatic arthritis. Direct comparison was based on a literature search of drug comparison studies, whereas indirect treatment comparison was based on phase III clinical trials with biological agents, involving similar populations and durations, and with the same outcome. ACR50 was taken as primary outcome for comparison, whereas ACR20 and ACR70 were used as secondary outcomes. Indirect comparisons were made using infliximab as the reference drug and the Bucher method. In calculating δ (the maximum acceptable difference as a clinical criterion of equivalence), use was made of half of the absolute risk reduction obtained in the meta-analysis of the clinical trials included in the indirect comparison (ARR 32%; δ: 16%). The four anti-TNF drugs were also compared in relation to the secondary outcomes and adverse effects. Reported direct and indirect comparisons of the four drugs did not include golimumab, and did not yield conclusive results. Four clinical trials - one for each drug studied - were identified. The estimated differences for the primary outcome, ACR50, between infliximab and the other drugs were adalimumab (ARR 4%, 95% CI -9·5 to 17·5), etanercept (ARR 4%, 95% CI -10·5 to 18·5) and golimumab (ARR 9%, 95% CI -5·4 to 23·4). Likewise, there were no relevant differences between the drugs in relation to the secondary efficacy outcomes, except for etanercept, which was less effective in ACR70 response. For adverse reactions, there were also no significant differences except for injection site, reactions which were more frequent with etanercept, with a mean difference of 26% relative to infliximab. No significant differences were found in ACR50 responses to the four drugs after 24weeks. Injection-site reactions were more common with etanercept, but this was insufficient to invalidate the inference that clinically the four drugs can be regarded as clinically equivalent for the treatment of psoriatic arthritis.

When can we ignore the problem of imperfect detection in comparative studies?

Summary1. Numbers of individuals or species are often recorded to test for variations in abundance or richness between treatments, habitat types, ecosystem management types, experimental treatments, time periods, etc. However, a difference in mean detectability among treatments is likely to lead to the erroneous conclusion that mean abundance differs among treatments. No guidelines exist to determine the maximum acceptable difference in detectability.2. In this study, we simulated count data with imperfect detectability for two treatments with identical mean abundance (N) and number of plots (nplots) but different mean detectability (p). We then estimated the risk of erroneously concluding that N differed between treatments because the difference in p was ignored. The magnitude of the risk depended on p, N and nplots.3. Our simulations showed that even small differences in p can dramatically increase this risk. A detectability difference as small as 4–8% can lead to a 50–90% risk of erroneously concluding that a significant difference in N exists among treatments with identical N = 50 and nplots = 50. Yet, differences in p of this magnitude among treatments or along gradients are commonplace in ecological studies.4. Fortunately, simple methods of accounting for imperfect detectability prove effective at removing detectability difference between treatments.5. Considering the high sensitivity of statistical tests to detectability differences among treatments, we conclude that accounting for detectability by setting up a replicated design, applied to at least part of the design scheme and analysing data with appropriate statistical tools, is always worthwhile when comparing count data (abundance, richness).

Survival and recovery of apheresis platelets stored in a polyolefin container with high oxygen permeability

Oxygen permeability is important in platelet storage media. We compared a new polyolefin container with enhanced oxygen permeability (PO-80; Kawasumi, Tokyo, Japan) to a widely used alternative (PL2410; Baxter Healthcare, Deerfield, IL, USA). In vitro characteristics of paired platelet concentrates (PCs; mean 4.2 x 10(11)/250 ml plasma/bag) stored in PO-80 or PL2410 were assessed through 9 days of storage. In vivo recovery and survival of 7-day-old autologous PCs were assessed according to the Murphy method. Laboratory assessment of platelet quality favoured PO-80 during 9 days of storage with statistically significant differences in glucose consumption (2.75 vs. 4.93 mmol/10(12)/24 h in the interval 120-168 h), lactate generation (4.37 vs. 8.11 mmol/10(12)/24 h in the interval 120-168 h), pressure of oxygen (pO(2)) (59.3 vs. 38.1 mmHg at day 1), and HCO(3)(-) (14.7 vs. 13.4 mmol/l at day 1). Statistically significant differences were not seen in aggregation, hypotonic shock response or pH. In vivo assessment of autologous platelets stored 7 days in the PO-80 container revealed that recovery was 82.1% and survival was 81.0% of fresh control. Seven-day stored PCs in PO-80 were shown in vivo to be non-inferior to fresh platelets, with upper confidence limits (UCL(95)) in recovery and survival of stored PCs below the maximum acceptable difference (MAD); 15.3% UCL(95) < 20.4% MAD and 2.1 days UCL(95) < 2.1 days MAD. The in vitro characteristics of PCs stored in a highly oxygen-permeable container were stable at least 7 days. The in vivo study supports the suitability of PO-80 for 7-day platelet storage.

Analysis and reporting of platelet kinetic studies

BACKGROUND: For platelet (PLT) kinetic studies in the healthy subject, autologous transfusion models are standardly used for the evaluation of new or modified PLT collection or treatment methods. The investigator is usually seeking to demonstrate that the new product is not inferior to a control condition. Consistent, statistically sound analysis and reporting methods will enable clear interpretation and communication of the results.STUDY DESIGN AND METHODS: Noninferiority hypotheses are constructed in light of a recent FDA workshop. One‐ and two‐stage analysis methods are described to evaluate the paired differences in control and test arms with calculation of upper confidence intervals. Sample size estimates are presented for various experimental design options. The sensitivity of sample size to the difference in test and control recoveries is performed.RESULTS: The noninferiority hypothesis test was applied to a recently published study. Seven‐day, plasma‐stored apheresis PLTs were shown to be noninferior to freshly prepared PLTs with 95 percent confidence that the difference in recovery was not more than 11.4 percent and survival not more than 2.6 days, with maximum acceptable differences of 19.8 percent and 4.4 days. As the test recovery and survival approach the minimum acceptable value, the sample size required to demonstrate noninferiority increases nonlinearly. Preliminary sample size calculations presented here suggest that for most studies such as this, a minimum sample size of 7 should be anticipated. Because most of these studies are used to support regulatory submissions, this is usually executed in at least two centers for a total minimum of 14.CONCLUSION: The randomized, paired design is the most efficient approach to these studies. Consistent reporting of summary statistics for each test arm and the paired differences, the upper confidence limit for the differences in recovery and survival, and the maximum acceptable difference for each is recommended.

Comparing no-touch and tympanic thermometer temperature recordings

Temperature is a vital sign which can be measured using various types of clinical thermometers. Pulmonary artery temperature is considered the 'gold standard', but this measurement is not usually clinically practical. There is currently no consensus for optimal alternative site or equipment. This research compares 178 simultaneous measurements from 5 clinical areas, using two types of thermometers: tympanic and no-touch temporal. No-touch thermometers were all set to oral equivalent. Tympanic thermometers were adjusted to either oral (n=105) or core (n=73) equivalent. Maximum acceptable difference was identified as 1oC. Two data sets (oral/core; oral/oral) were analysed using Bland-Altman method on Excel programmes, comparing all thermometers and separating oral and core-equivalent tympanics. The two thermometers were found not to be equivalent. As a simple comparison between two thermometers, this research cannot identify which thermometer is more accurate.

Observations on the Determination of Free Swelling Index of Coal

It is the purpose of this paper to discuss the problems of analytical technics in relation to the difference between JIS M8801 and ISO R501.Subjects included are as follows:1. Difference in gas heating method and electrical heating method (ISO R501).1.1 Comparison of mean values of two methods.1.2 Comparison of precisions of two methods.2. Effect of difference in weight of crucibles.3. Tolerances (maximum acceptable difference of the serial test) of two methods.4. Adoption of caribration curve for the determination of F.S. I.It is concluded that, (1) the differences in mean values and precisions of two methods are not significant, (2) there is no difficulty for employing the electrical heating method in revised JIS M8801 and (3) the effect of difference in weights of crucibles is negligible small.