Small Percentage Differences Research Articles

Evaluation of the Ultrasonic Flaw Detector Inspection on Single Vee Butt Welded of Carbon Steel Plate Using Three Different Couplant

Carbon steel plate with single vee butt welded was inspected with an ultrasonic flaw detector (UTFD) using an angle probe. Various types of couplants have been used to study their effects on ultrasonic transmission. The acoustic impedance of the couplant affects the transmission of ultrasonic waves. As a result, welding flaws were found on the root and central area of the butt weld plate. The results also show that honey has the smallest percentage difference (234.42) in terms of size accuracy compared to water (362.89) and baby oil (370.04) in identifying and measuring defect size. However, there are other factors to be considered when performing an UTFD testing. In summary, UTFD is the only method of NDT that can detect and measure all subsurface defects in the weld area, and honey gave the best results for the couplant used.

Toward hippocampal volume measures on ultra-high field magnetic resonance imaging: a comprehensive comparison study between deep learning and conventional approaches.

The hippocampus is a complex brain structure that plays an important role in various cognitive aspects such as memory, intelligence, executive function, and path integration. The volume of this highly plastic structure is identified as one of the most important biomarkers of specific neuropsychiatric and neurodegenerative diseases. It has also been extensively investigated in numerous aging studies. However, recent studies on aging show that the performance of conventional approaches in measuring the hippocampal volume is still far from satisfactory, especially in terms of delivering longitudinal measures from ultra-high field magnetic resonance images (MRIs), which can visualize more boundary details. The advancement of deep learning provides an alternative solution to measuring the hippocampal volume. In this work, we comprehensively compared a deep learning pipeline based on nnU-Net with several conventional approaches including Freesurfer, FSL and DARTEL, for automatically delivering hippocampal volumes: (1) Firstly, we evaluated the segmentation accuracy and precision on a public dataset through cross-validation. Results showed that the deep learning pipeline had the lowest mean (L = 1.5%, R = 1.7%) and the lowest standard deviation (L = 5.2%, R = 6.2%) in terms of volume percentage error. (2) Secondly, sub-millimeter MRIs of a group of healthy adults with test-retest 3T and 7T sessions were used to extensively assess the test-retest reliability. Results showed that the deep learning pipeline achieved very high intraclass correlation coefficients (L = 0.990, R = 0.986 for 7T; L = 0.985, R = 0.983 for 3T) and very small volume percentage differences (L = 1.2%, R = 0.9% for 7T; L = 1.3%, R = 1.3% for 3T). (3) Thirdly, a Bayesian linear mixed effect model was constructed with respect to the hippocampal volumes of two healthy adult datasets with longitudinal 7T scans and one disease-related longitudinal dataset. It was found that the deep learning pipeline detected both the subtle and disease-related changes over time with high sensitivity as well as the mild differences across subjects. Comparison results from the aforementioned three aspects showed that the deep learning pipeline significantly outperformed the conventional approaches by large margins. Results also showed that the deep learning pipeline can better accommodate longitudinal analysis purposes.

Correlation model of deflection and rotation on pci girder bridge

A bridge is an infrastructure that experiences dynamic and repetitive loading for a long period, so it is necessary to monitor the condition of the bridge structure to ensure that the bridge is always in proper condition. Deflection is the vertical displacement that can occur in the bridge. This study aims to obtain an correlation model in the form of regression equation with multiple regression analysis methods between the deflection value and the rotation value of the PCI Girder bridge. The analysis was carried out using Finite Element Method software, by modeling the PCI Girder bridge with several vehicle load cases, and the rotation and deflection values of the bridge will be obtained. Several schemes were made regarding the number and location of rotation sensors to determine the level of accuracy. To get the relationship between rotation value and deflection value, a multiple linear regression analysis was carried out. It can be generated a multiple linear regression equation with the dependent variable being the deflection value and the independent variable being the rotation value on the bridge placement. This equation can be used to predict the deflection value in the middle of the bridge span with the percentage difference shows value smaller than 5%. In the analysis, it is able to provide results with the smallest percentage difference between numerical comparison values and linear regression equations.

A practical empirical formula for the calculation of ship added friction-resistance due to (bio)fouling

An accurate prediction of the ship added friction-resistance due to (bio)fouling is important in the maritime sector in view of environmental sustainability. For industrial needs, the prediction method must not only be accurate but also be practical. An empirical formula is proposed in this study for the calculation of ship added friction-resistance due to (bio)fouling. An optimization method was applied, in which the objective function is defined as the least mean square error between the predicted results and data derived from Demirel et al.'s diagrams. The mathematical model to be fitted with the data involves power functions whose form resembles the functional relationship between the added friction-resistance coefficient and Reynolds number, and between the added friction-resistance coefficient and roughness ratio. The coefficients, powers and constant in the mathematical model were determined by using a nonlinear generalized reduced-gradient method. Comparisons of the formula predictions with CFD calculation results for a flat plate and the Kriso Container Ship show a small percentage difference of less than 5%. Further, the formula predictions differ less than 12% from the results obtained from methods utilizing topographical roughness parameters available in the literature.

A measurement validation of improved plan deliverability with monitor unit objective tool for spine stereotactic ablative radiotherapy.

Spine stereotactic body radiation therapy (SBRT) uses high dose per fraction for palliative pain control. The treatment plans are often heavily modulated due to close proximity to spinal cord and this can lead to poor plan quality which are susceptible to dose delivery discrepancy. Therefore, we aim to assess the effectiveness of the monitor unit (MU) objective tool in Eclipse treatment planning systems in modulating the plan complexity to improve the plan quality in spine SBRT. Seven retrospective spine SBRT plans are re-optimized using the MU objective tool in Eclipse TPS v13.6 and were compared with the original plans. The dose metrics of the tumor PTV were compared using D1cc. D99%, D95%, D0.03cc, D0.1cc, D0.35cc and D1cc, and that of cord PRV were compared using D0.03cc, D0.1cc, D0.35cc. Four different plan complexities were also calculated for the original and re-optimized plans to quantify the impact of the tool on the modulation. Patient specific quality assurance measurements were performed with Stereophan and SRS MapCheck, and analyzed using the 1%/1-mm and 2%/2-mm criteria with gamma analysis. The dose metrics of the PTV and cord PRV of the re-optimized and original plans are similar and still meet the planning dose constraints. In particular, the PTV dose coverage has a small percentage difference of (0.15 ± 1.33)% and (0.01 ± 1.04)% for D99% and D95%, respectively. The 4 calculated plan complexity metrics consistently show that the re-optimized plans are quantitatively less complex than the original plan. The gamma passing rate of the re-optimized plans improved from (92.2 ± 2.0)% to (94.2 ± 1.6)% with the 1%/1-mm criterion, and (98.7 ± 1.0)% to (99.5 ± 0.3)% with the 2%/2-mm criterion. Overall, the re-optimized plans achieve at least a 10% MU reduction (11.7% to 24.6%). Our study shows that optimization with the MU objective tool can reduce plan complexity and improves dose delivery accuracy, while not compromising the dose distribution.

Optimisation and performance evaluation of response surface methodology (RSM), artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) in the prediction of biogas production from palm oil mill effluent (POME)

In recent years, machine learning (ML) techniques have been developed to predict the performance of anaerobic digestion (AD) processes including methane potential and reactor stability. However, their practical applications to industrial-scale palm oil mill effluent (POME) treatment plant are limited. In this study, ML algorithms such as response surface methodology (RSM), adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) are employed to model the biogas production and methane yield from the AD of POME in a local industry-scale anaerobic covered lagoon. Results demonstrated that these models were well aligned with two years of operational data with high coefficient of determination (R2) of up to 0.98. ANFIS yields the highest prediction accuracy, with R2 of 0.9791 along with the lowest mean absolute error (MAE) of 0.0730 and root mean squared error (RMSE) of 0.1438. Subsequently, ANFIS is used in the multi-objective optimisation to maximise the biogas production and methane yield. Optimal conditions for the temperature of the anaerobic digester, pH and recirculation ratio are 38.9 °C, 7.03 and 1.89 respectively which could enhance the biogas production and methane yield by 19.4% and 12.2% respectively. Confirmatory experiments were carried out in the biogas plant under this set of optimised variables for a period of two months. The predicted biogas production and methane yield are highly correlated to the actual data with small percentage difference of 1.25% and 5.09% respectively, indicating that ANFIS model was accurate and reliable. Sensitivity analysis shows that pH has the most dominant effect on the methane yield.

Prediction of Fluid Behavior Using Generalized Hydraulic Calculation Method in Hydraulic Fractures

Hydraulic fracturing has been used as one of the stimulation techniques to economically increase oil and gas production by creating small cracks in subsurface geologic formations to allow oil or gas to move toward a producing well. Hydraulics plays a vital role in many oil field operations including drilling, completion, fracturing and production. In the case of fracturing, however, the role of hydraulics becomes important since optimized hydraulics can minimize the cost and conversely, any miscalculations may cause problems such as the fluid loss or may potentially even lead to loss of the well. The current methods of the hydraulic calculation for non-Newtonian fluids necessitate determination of the robust model. This paper presented a new method for calculating pressure losses in the hydraulic fractures. The objective of this study was to develop the generalized model for hydraulic calculation for non-Newtonian fluid and run the case studies for the model validation. In the present work, detailed algorithm for the hydraulic calculation has been developed and then programmed in C++. The only input to the program is the raw rheological data, shear stress versus shear rate and the geometrical characteristics of the slit. Model validation with the new method has established a very small percentage difference between the values predicted by the model and experimental data. The results demonstrate that the new method is accurately predicting the pressure drop in both laminar and turbulent flow regimes. It is shown that the fluid behavior is more accurately represented using the new method than that with the standard fluid models available in the petroleum industry. Further validation and development to be carried out using experimental data for variety of fluid types.

EVALUASI ISI AWAL GAS DI TEMPAT DAN ANALISIS DECLINE CURVE PADA RESERVOIR YS

YS reservoir has data of gas initial in place (GIIP) with a volumetric method of 3,476 Bscf. Because of improvement of data, GIIP can be evaluated using material balance method. Then the production of wet gas will be forcasted with plateu rate of 40 Mscf/d. The PVT data that needs to be calculated in this study is the gas and water compressibility factor and the formation volume factor each year. In determining the type of drive mechanism, a plot of P / Z versus cumulative gas production is carried out, from the analysis, the type of drive mechanism is water drive, it is necessary to calculate the water influx, the method used is the Van Everdengen-Hurst method. After all the required parameters are available, the calculation of the initial gas in place will be calculated, the method used is the material balance method and the straight line material balance method. The results of the initial gas in place calculation using the material balance and straight line material balance methods are 3,430 Bscf and 3,428 Bscf. If the results of the material balance method and the straight line material balance method are compared with available GIIP volumetric method data, the percent difference is 1,32% and 1,37%. It can be said that GIIP result using the material balance method and the straight line material balance method is accurate because after being evaluated using volumetric method, it only has a small percentage difference. Then from calculation, recovery factor are 67,43% using gas initial in place of straight line material balance method. With remaining reserve of 16,532 MMscf, the time of production plateu with 40 Mscf/d is 12,40 months.

Structural and Electronic Properties of Orthorhombic Phase Bi2Se3 Based On First-Principles Study

Bi2Se3 is one of the promising materials in thermoelectric devices and very useful out of environmental concern due to its efficiency to perform at room temperature. Based on the first-principles calculation of density functional theory (DFT) by using CASTEP computer code, structural and electronic properties of Bi2Se3 were investigated. The calculation is conducted within the exchange-correlation of local density approximation (LDA) and generalized gradient approximation within the revision of Perdew-Burke-Ernzerhof (GGA-PBE) functional. It was found that the results are consistent with previous works of theoretical study with small percentage difference. LDA exchange-correlation functional method is more accurate and have a better agreement than GGA-PBE to describe the structural properties of Bi2Se3 which consist of lattice parameters. LDA functional also shown more accurate electronic structure of Bi2Se3 that consist of band structure and density of states (DOS) which consistent with most previous theoretical works with small percentage difference. This study proves the reliability of CASTEP computer code and show LDA exchange-correlation functional is more accurate in describing the nature of Bi2Se3 compared to the other functionals.

FatSegNet: A fully automated deep learning pipeline for adipose tissue segmentation on abdominal dixon MRI.

Introduce and validate a novel, fast, and fully automated deep learning pipeline (FatSegNet) to accurately identify, segment, and quantify visceral and subcutaneous adipose tissue (VAT and SAT) within a consistent, anatomically defined abdominal region on Dixon MRI scans. FatSegNet is composed of three stages: (a) Consistent localization of the abdominal region using two 2D-Competitive Dense Fully Convolutional Networks (CDFNet), (b) Segmentation of adipose tissue on three views by independent CDFNets, and (c) View aggregation. FatSegNet is validated by: (1) comparison of segmentation accuracy (sixfold cross-validation), (2) test-retest reliability, (3) generalizability to randomly selected manually re-edited cases, and (4) replication of age and sex effects in the Rhineland Study-a large prospective population cohort. The CDFNet demonstrates increased accuracy and robustness compared to traditional deep learning networks. FatSegNet Dice score outperforms manual raters on VAT (0.850 vs. 0.788) and produces comparable results on SAT (0.975 vs. 0.982). The pipeline has excellent agreement for both test-retest (ICC VAT 0.998 and SAT 0.996) and manual re-editing (ICC VAT 0.999 and SAT 0.999). FatSegNet generalizes well to different body shapes, sensitively replicates known VAT and SAT volume effects in a large cohort study and permits localized analysis of fat compartments. Furthermore, it can reliably analyze a 3D Dixon MRI in ∼1minute, providing an efficient and validated pipeline for abdominal adipose tissue analysis in the Rhineland Study.

Analysis on key financial data of Hungarian dairy product manufacturing enterprises

After several years of decline, dairy herd and milk production have started to rise from 2011. Considering the first growth phase, in current article we analysed the enterprises operating in the dairy product manufacturing sector in the period of 2012-2016. Among the principal financial indicators, we have chosen ROA and ROE to determine the general financial situation of the enterprises and analyse the changes in the five-year period. Based on the literature review we made our analysis by dimensions of enterprise size categories and regions. Income statement and balance sheet needed for calculating financial indicators of enterprises have been downloaded from EMIS. Enterprises involved in our analysis belonging to small, medium and large size category and mean representative sample as this sample covers 30% of the total population. Share of sample enterprises from key performance indicators is similar to the total population so we can consider our sample representative also in this respect. The average rate of ROA showed growth from 2012 to 2016 for all regions and the largest increase occurred in the Northern Great Plain. Moreover, this region experienced the strongest increase in the average export share (from 4% to 20%), but three regions showed some decrease. The average rate of ROE calculated for the Central-Hungarian region, however, declined. Total assets value of enterprises analysed increased in the five years under consideration, however, this growth is mainly due to the increase of assets of large enterprises. The share of large companies from the total assets rose by 7% during the five years (from 64% to 71%), while the share of small and medium sized enterprises fell. Considering small enterprises, the total value of the domestic sales revenue in 2016 declined by 30% below the level of 2012. In the first two years analysed, a significant recovery of export revenues was noted, the total value export sales revenues almost doubled from 2012 to 2014. Domestic sales revenues of medium sized enterprises in 2016 show only a small percentage difference compared to 2012, but the trend of export sales is similar to small companies. The increase of domestic and export sales revenue of large companies is slight but continuous. Indicators of ROA and ROE show dynamic increase for large companies during the five years. Medium sized enterprises also experienced growth, however, in the last the years considered there was a fall. ROA calculated for small enterprises became positive, but its value is volatile, while ROE clearly show a continuing decrease.

EVALUASI ISI AWAL GAS DI TEMPAT DAN ANALISIS DECLINE CURVE PADA RESERVOIR YS

YS reservoir has data of gas initial in place (GIIP) with a volumetric method of 3,476 Bscf. Because of improvement of data, GIIP can be evaluated using material balance method. Then the production of wet gas will be forcasted until below economic limit. The PVT data that needs to be calculated in this study is the gas and water compressibility factor and the formation volume factor each year. In determining the type of drive mechanism, a plot of P / Z versus cumulative gas production is carried out, from the analysis, the type of drive mechanism is water drive, it is necessary to calculate the water influx, the method used is the Van Everdengen-Hurst method. After all the required parameters are available, the calculation of the initial gas in place will be calculated, the method used is the material balance method and the straight line material balance method. The results of the initial gas in place calculation using the material balance and straight line material balance methods are 3,430 Bscf and 3,428 Bscf. If the results of the material balance method and the straight line material balance method are compared with available GIIP volumetric method data, the percent difference is 1,32% and 1,37%. It can be said that GIIP result using the material balance method and the straight line material balance method is accurate because after being evaluated using volumetric method, it only has a small percentage difference. Then from the decline curve and Trial Error and X2 – Chisquare Test analysis, the decline curve is exponential with Di at 1,103 / month. After forecasting until production of wet gas is below the economic flow rate of 0,045 Mscf / d, it is known that the productive age is until 1st September 2021 with the values of EUR and RR respectively 2,309 and 0,014 Bscf. Using the results of GIIP using the material balance and straight line method, the current recovery factor are 67,34% and 67,37 %.

Validation of Corner Beam-column Joint’s Hysteresis Loops between Experimental and Modelled using HYSTERES Program

The beam - column joint is an important part of a multi-storey RC building as it caters for lateral and gravitational load during an earthquake event. The beam-column joints should have a medium to high ductility for transferring the earthquake load and gravity load to the foundation. By designing multi-storey RC buildings using Eurocode 8 can avoid any diagonal shear cracks in column which is a major problem in non-seismic design buildings using British Standard (BS8110). This paper presents the experimental hysteresis loops of monolithic corner beam-column joints of multi-storey building which had been designed using Eurocode 8 and tested under in-plane lateral cyclic loading. The experimental hysteresis loops of corner beam-column joint was compared with modelled using the HYSTERES program. The full-scale corner beam-column joint of a two story precast school building was designed, constructed, tested and modelled is presented herein. The seismic performance parameters such as lateral strength capacity, stiffness, ductility and equivalent viscous damping were compared between experimental and modelled hysteresis loops. The experimental hysteresis loops have similar shape with the modeling hysteresis loops with small percentage differences between them.

Impact of region of interest size and location in Gafchromic film dosimetry

Introduction: Accurate film dosimetry requires careful consideration of sources of uncertainty. Some of the sources of uncertainty are dependent on the size and location of region of interest (ROI), especially in small fields. Avoiding the penumbra is often a reason for using a small ROI. In contrast, choosing very small ROIs may increase uncertainty due to the reduction of the sampling data. Using a dose profile as flat as possible for the ROI becomes more significant in small fields in which the flatness of profile is greatly affected by the penumbra. This study aims to evaluate dependency of measured dose on size and location of region of interest (ROI) in Gafchromic EBT3 film for small field dosimetry. Materials and Methods: Gafchromic EBT3 films were irradiated using the 6MV beam from a linear accelerator at 10 cm depth (100 cm SSD) of a solid water phantom for a range of field sizes of 6×6 to 100×100 mm2. For scanning, 48 bits RGB mode with a spatial resolution of 72 dpi was used. The red channel of ImageJ software was used for evaluation. The appropriate location of ROIs were found by two methods. First, the ROI was visually placed at the center of image. Second, the profile of pixel value versus distance was plotted and the center of profile was used. Each scanned film was read using both methods and for three ROI sizes (1, 2, and 4 mm). In every scan, the film was re-positioned in the center of scanner. This uncertainty was compared with scan-to-scan variability when using piece of glass on top of the film. A plastic scintillator, Exradin W1, was used as a reference dosimeter. To obtain doses from W1 scintillator, a calibrated ion chamber with the same setup as W1 was used. Results: Comparing the three ROI sizes using both methods showed that there is less than 2% difference from reference in output factor measurements for field sizes larger or equal to 10×10 mm2. For field sizes of 15×15 and 10×10 mm2, the smaller mean percentage differences were observed in profiled-ROI (4×4 mm2) and centered-ROI (4×4 mm2). For the field sizes of 8×8 and 6×6 mm2, the profiled-ROI (2×2 mm2) had smallest mean percentage difference, which was 0.88%. The scan to scan variability was less than 0.31%. Conclusion: The ROI size of 4×4 mm2 is appropriate for dose measurements in field sizes of 100×100 mm2 to 10×10 mm2, regardless of the method of finding location of ROI. In field sizes smaller than 10×10 mm2, finding location of the ROI by profile of pixel values increases the accuracy of measurement, and ROI size of 2×2 mm2 has the smallest difference from the reference dose measurements.

Designing an education programme to improve quality of life for cancer survivors: a systematic review.

Health and wellbeing education programmes, as part of the recovery package, are now recommended for all cancer patients on completion of treatment. There is limited evidence to determine whether such programmes improve the quality of life (QoL) for cancer survivors. The purpose of the systematic review was to synthesise the available research and provide recommendations for practice and education programme delivery. A critical appraisal and narrative synthesis of eligible randomised controlled trials showed that there was a small mean percentage difference in reported QoL for cancer survivors who participated in an education programme (8%) over those who received usual care alone (7%). Cancer-site specific programmes are recommended over generic programmes. The optimum time frame for programme delivery is between 3 and 12 months following treatment. Various methods of programme delivery are effective, including face-to-face group sessions and self-directed web-based programmes.

Otimização do método dos molinetes com ajuste do perfil hidrodinâmico para a estimação da descarga líquida em corpos hídricos usando recursos de interpolação e integração numérica

In the last years, there has been an increase in computational analyses in the study of hydrodynamic profiles for the determination of flows in watercourses as an attempt to reduce inaccuracies in traditional calculations. This article aims to develop an algorithm for the determination of flow rates in open channels using numerical procedures to optimize the hydrometric windlasses method in order to reduce the time in data analyzes and to provide a detailed treatment of velocities as a function of depth. In this article, the input data used in the computational project result from the measuring campaign present in Literature,which was carried out in the Braço do Norte river, in the Tubarão river basin, at the point where the São Ludgero Hydrometeorological Station, of National Waters Aggency (ANA), is located, in SC. Regarding the method of the windlasses in their traditional form,the model presented in this work presents small percentage differences of estimates This allows the validation of the proposed model and means that the use of numerical integrations and interpolations, especially the cubic splines, for the modeling of the flow measurement in watercourses is satisfactory and it can be used in the practice of instrumentation and measurement.

Radiometric validation of atmospheric correction for MERIS in the Baltic Sea based on continuous observations from ships and AERONET-OC

The Baltic Sea is a semi-enclosed sea that is optically dominated by coloured dissolved organic material (CDOM) and has relatively low sun elevation which makes accurate ocean colour remote sensing challenging in these waters. The high absorption, low scattering properties of the Baltic Sea are representative of other optically similar water bodies including the Arctic Ocean, Black Sea, coastal regions adjacent to the CDOM-rich estuaries such as the Amazon, and highly absorbing lakes where radiometric validation is essential in order to develop accurate remote sensing algorithms. Previous studies in this region mainly focused on the validation and improvement of standard Chlorophyll-a (Chl a) and attenuation coefficient (kd) ocean colour products. The primary input to derive these is the water-leaving radiance (Lw) or remote sensing reflectance (Rrs) and it is therefore fundamental to obtain the most accurate Lw or Rrs before deriving higher level products. To this end, the retrieval accuracy of Rrs from Medium Resolution Imaging Spectrometer (MERIS) imagery using six atmospheric correction processors was assessed through above-water measurements at two sites of the Aerosol Robotic Network for Ocean Colour (AERONET-OC; 363 measurements) and a shipborne autonomous platform from which the highest number of measurements were obtained (4986 measurements). The six processors tested were the CoastColour processor (CC), the Case 2 Regional processor for lakes (C2R-Lakes), the Case 2 Regional CoastColour processor (C2R-CC), the FUB/WeW water processor (FUB), the MERIS ground segment processor (MEGS) and POLYMER. All processors except for CC had small average absolute percentage differences (ψ) in the wavelength range from 490nm to 709nm (ψ<40%), while other bands had larger differences with ψ>60%. Compared to in situ values, the Rrs(709)/Rrs(665) band ratio had ψ<30% for all processors. The most accurate Rrs in the 490 to 709nm domain was obtained from POLYMER with ψ<30% and coefficients of determination (R2)>0.6. Using a score system based on all statistical tests, POLYMER scored highest, while C2R-CC, C2R-Lakes and FUB had lower scores. This study represents the largest data base of in situ Rrs, the most comprehensive analysis of AC models for highly absorbing waters and for MERIS, conducted to date. The results have implications for the new generation of Copernicus Sentinel ocean colour satellites.

Development, validation and reproducibility of a food frequency questionnaire to measure flavonoid intake in older Australian adults.

To develop and assess the validity and reproducibility of a food frequency questionnaire (FFQ) to measure total flavonoid intake, and individual flavonoid subclasses, in older adults. Retrospective analysis of flavonoid intake in older adults informed the development of a FFQ to measure flavonoid intake and determine the flavonoid subclasses consumed (anthocyanins, flavan-3-ols, flavones, flavonols and flavanones). Older adults (n = 42, mean age 75.3 ± 8.6 years) attended two interviews 1 month apart where anthropometrics (height and weight), blood pressure (BP), demographic data and a 93-item self-administered FFQ were collected. A 4-day food record (FR) was randomly administered between the two interview dates, and each food item was assigned a flavonoid and flavonoid subclass content using the United States Department of Agriculture flavonoid database. The criterion validity and reproducibility of the FFQ was assessed against a 4-day FR using the Wilcoxon signed-rank sum test, Spearman's correlation coefficient (r), Bland-Altman Plots and Cohen's kappa. Total flavonoid intake was determined (median intake FFQ = 919.3 mg/day, FR = 781.4 mg/day). Tests of validity indicated that the FFQ consistently overestimated total flavonoid intake compared with the 4-day FR. There was a significant difference in estimates between the FFQ and the 4-day FR for total flavonoid intake (Wilcoxon signed-rank sum P < 0.001; Bland-Altman plots indicated large bias and wide limits of agreement), but they were well correlated (Spearman's r 0.93, P < 0.001; Cohen's kappa κ = 0.619, P < 0.001). For individual flavonoid subclasses, the tests of validity indicated greater discrepancy compared with 4-day FR. The FFQ showed high reproducibility for estimating total flavonoid intake (FFQ1vsFFQ2: Wilcoxon signed-rank sum test, P > 0.05; Spearman's r 0.91, P < 0.001; Bland-Altman plots visually showed small, non-significant bias and wide limits of agreement; and Cohen's kappa κ = 0.619, P < 0.001), with a small mean percentage difference (6.7%). For individual flavonoid subclasses, the tests of reproducibility between FFQ1 and FFQ2 showed similarly high reproducibility. The developed FFQ appears suitable for satisfactorily ranking individuals according to total flavonoid intake. The FFQ shows limitations for estimating absolute total flavonoid intake and intake of flavonoid subclasses in comparison to a 4-day FR in terms of overestimating intake. Refinement and further validation of this tool may be required.

Relative Validity and Reproducibility of an Interviewer Administered 14-Item FFQ to Estimate Flavonoid Intake Among Older Adults with Mild-Moderate Dementia

ABSTRACTThere is a large burden on researchers and participants when attempting to accurately measure dietary flavonoid intake using dietary assessment. Minimizing participant and researcher burden when collecting dietary data may improve the validity of the results, especially in older adults with cognitive impairment. A short 14-item food frequency questionnaire (FFQ) to measure flavonoid intake, and flavonoid subclasses (anthocyanins, flavan-3-ols, flavones, flavonols, and flavanones) was developed and assessed for validity and reproducibility against a 24-hour recall. Older adults with mild-moderate dementia (n = 49) attended two interviews 12 weeks apart. With the assistance of a family carer, a 24-h recall was collected at the first interview, and the flavonoid FFQ was interviewer-administered at both time-points. Validity and reproducibility was assessed using the Wilcoxon signed-rank sum test, Spearman’s correlation coefficient, Bland-Altman Plots, and Cohen’s kappa. Mean flavonoid intake was determined (FFQ1 = 795 ± 492.7 mg/day, 24-h recall = 515.6 ± 384.3 mg/day). Tests of validity indicated the FFQ was better at estimating total flavonoid intake than individual flavonoid subclasses compared with the 24-h recall. There was a significant difference in total flavonoid intake estimates between the FFQ and the 24-h recall (Wilcoxon signed-rank sum p < 0.001; Bland-Altman plots indicated large bias and wide limits of agreement), but they were well correlated (Spearman’s correlation coefficient r = 0.74, p < 0.001; Cohen’s kappa κ = 0.292, p < 0.001). The FFQ showed good reproducibility, with a small mean percentage difference (12.6%). The Wilcoxon signed-rank sum test showed no significant difference, Spearman’s correlation coefficient indicated excellent reliability (r = 0.75, p < 0.001), Bland-Altman plots visually showed small, nonsignificant bias and wide limits of agreement, and Cohen’s kappa indicated fair agreement (κ = 0.429, p < 0.001). A 14-item FFQ developed to easily measure flavonoid intake in older adults with dementia demonstrates fair validity against a 24-h recall and good reproducibility.

Debates on fetal fraction measurement and DNA-based noninvasive prenatal screening: time for standardisation?

Debates on fetal fraction measurement and DNA-based noninvasive prenatal screening: time for standardisation?