Overall Coefficient Of Variation Research Articles

Intra- and interindividual variability in fasted gastric content volume.

Gastric fluid plays a key role in food digestion and drug dissolution, therefore, the amount of gastric fluid present in a fasted state may influence subsequent digestion and drug delivery. We aimed to describe intra- and interindividual variation in fasted gastric content volume (FGCV) and to determine the association with age, sex, and body size characteristics. Data from 24 MRI studies measuring FGCV in healthy, mostly young individuals after an overnight fast were pooled. The analysis included 366 participants who had up to 6 repeated measurements, with a total of 870 measurements. Linear mixed model analysis was performed to calculate intra- and interindividual variability and to assess the effects of age, sex, weight, height, weight*height as a proxy for body size, and body mass index (BMI). FGCV ranged from 0 to 156 mL, with a mean (± SD) value of 33 ± 25 mL. The overall coefficient of variation within the study population was 75.6%, interindividual SD was 15 mL, and the intraindividual SD was 19 mL. Age, weight, height, weight*height, and BMI had no effect on FGCV. Women had lower volumes compared to men (MD: -6 mL), when corrected for the aforementioned factors. FGCV is highly variable, with higher intraindividual compared to interindividual variability, indicating that FGCV is subject to day-to-day and within-day variation and is not a stable personal characteristic. This highlights the importance of considering FGCV when studying digestion and drug dissolution. Exact implications remain to be studied.

Temperature related to the spatial heterogeneity of wetland soil total nitrogen content in a frozen zone

Changes in soil total nitrogen (N) content would affect wetland function and the global N cycle. Determination of spatial heterogeneity controlling factors of wetland soil total N content per unit mass is essential to assess responses of ecosystem N cycle to global change. However, such information is limited in permafrost zones because few soil profiles have been acquired and methods to predict spatial distributions of wetland soil total N content in large areas are inefficient, which increase uncertainty in evaluations of N cycle at national or global scales. To determine the spatial heterogeneity of wetland soil total N content at different soil depths and frozen zones and the factors controlling wetland soil total N content in the frozen zones of Northeast China, the spatial pattern of wetland soil total N content was investigated by using a random forest method that combined field samples with environmental factors. Vertically, wetland soil total N content decreased with increasing soil depth, with the highest content in the top soil layer (0–30 cm). Spatially, wetland soil total N content decreased from northwest to southeast, with relatively high total N content in a continuous permafrost zone and relatively low total N content in a seasonally frozen zone. The overall coefficient of variation of wetland soil total N content in the frozen zones of Northeast was 29.58 %, indicating moderate variation. Land surface temperature, mean annual temperature, and mean annual humidity significantly affected total N content in 0–30 and 30–60 cm soil layers, suggesting that variations in temperature and humidity altered sequestration processes of wetland soil total N content. In the 60–100 cm soil layer, compared with other environmental factors, mean annual humidity, altitude, and mean annual precipitation had the greatest influence on the spatial distribution of wetland soil total N content. The study unravels the spatial pattern of soil total N content in frozen zones of Northeast China and reflects the direct and indirect effects of environmental factors on total N content. This provides a basis for the management and protection of wetland ecosystems.

A Comprehensive Analysis of 10-Yard Sprint Reliability in Male and Female Youth Athletes.

Wannouch, YJ, Leahey, SR, Whitworth-Turner, CM, Oliver, JL, YH, KC, Laffer, JC, and Leicht, AS. A comprehensive analysis of 10-yard sprint reliability in male and female youth athletes. J Strength Cond Res 38(9): e477-e488, 2024-This study investigates the inter-week test-retest reliability of 9.14 meter (10 yard) sprint times in youth athletes. Although essential for assessing athletic ability and training efficacy, the critical and comprehensive examination of both relative and absolute reliability indices for short-distance sprints has been insufficient in youth contexts. One hundred ninety-eight youth athletes (128 males and 70 females) underwent 2 sprint attempts across 2 separate trials 24 hours apart and within 7 days of each other. The sprints were measured using dual-beam timing gates to capture split times for 0-4.57 meter (0-5 yards), 4.57-9.14 meter (5-10 yards), and 0-9.14 meter (0-10 yards). The minimal mean difference between the best sprint times across trials was 0.02 ± 0.13 seconds for males and 0.003 ± 0.14 seconds for females. No significant mean differences were found between trials for either gender (males: p = 0.0875; females: p = 0.8752), suggesting no systematic bias in sprint times. The SEM was 0.092 seconds for males and 0.099 seconds for females, with a corresponding SEMCV% of 4.6 and 4.8%. The overall coefficient of variation was 9.8% for males and 8.9% for females. Intraclass correlation coefficient values suggested that the sprint times across trials were reliable (males: 0.80; females: 0.76). The minimal detectable change was 0.25 seconds for males, 0.27 seconds for females. Cohen's d indicated trivial effects (<0.2) for males (0.154) and females (0.021). Minimal mean differences, a low SEM , and consistent ICC values demonstrate that the 0-9.14 meter sprint is a reliable assessment in youth athletes.

Establishment and preliminary application of neutralizing antibody detection method for human respiratory syncytial virus

Objective: To establish a Plaque-reduction Neutralization Test (PRNT) for the detection of neutralizing antibody titers of Human Respiratory Syncytial Virus (HRSV) and optimize the conditions for preliminary application. Methods: The CHO expression system was used to produce palivizumab monoclonal antibody (palivizumab) and the influencing factors such as cell type, cell culture duration, fixation and permeabilization protocols, and blocking agents. The reproducibility of the method was verified and its correlation was verified with conventional PRNT. Finally, the optimized PRNT assay was further used to determine neutralizing antibody titers against HRSV subtypes A and B in BALB/c mouse serum (immunized by intramuscular injection of HRSV fusion proteins). Results: Palivizumab was expressed at approximately 50 mg/L. The optimal working conditions for PRNT were as follows: culturing HEp-2 cells for 2 days, fixing with 4% (V/V) paraformaldehyde at room temperature for 15 min followed by 0.2% (V/V) Triton X-100 permeabilization for 15 minutes as the optimal fixation-permeabilization and removing the blocking step. The overall coefficient of variation (CV) for the reproducibility validation of this method was <15%, showing a good linear relationship with the conventional PRNT. The Spearman correlation coefficient rs was 0.983. This method was used to detect neutralizing antibody titers in mouse sera against HRSV subtype A strain long and subtype B strain 9320, and the fusion proteins combined with AlOH and CpG adjuvant induced the highest neutralizing antibody titers in mice. Conclusion: The HRSV neutralizing antibody assay established in this study is rapid, reproducible, high-throughput, and can be used to detect neutralizing antibodies to HRSV subtypes A and B.

Enhancing and comparing shrinkage prediction models for High-Strength Concrete with and without admixtures

This study aimed to improve and compare the parameterization of three prominent shrinkage prediction models—RILEM B4, MC 2010, and WITS—tailored specifically for High-Strength Concrete (HSC), both with and without the inclusion of admixtures. The dataset used for refining model parameters consisted of 220 experiments related to drying shrinkage and 342 experiments concerning autogenous shrinkage. Model performance evaluation involved various statistical metrics applied to the entire HSC dataset, subdatasets, and distinct time periods of shrinkage (0–99 days, 100–199 days, 200–499 days, and ≥500 days). The statistical indicators included Root Mean Square Error (RMSE), R-squared adjusted (R2 adj), Akaike’s Information Criterion (AIC), and the overall coefficient of variation (C.o.Vall). Modified models exhibited significantly improved predictions compared to the original models, with most predictions falling within ±20% of the measured shrinkages. For HSC drying shrinkage, the original model accuracy ranked as WITS, RILEM B4, and MC 2010. However, after parameter adjustments, WITS, MC 2010, and RILEM B4 were the best-performing models. Conversely, for HSC autogenous shrinkage predictions, the RILEM B4 model surpassed the MC 2010 model, demonstrating superior accuracy and reliability in forecasting this specific type of shrinkage behaviour within High-Strength Concrete.

Random distribution of interphase characteristics on the overall electro-mechanical properties of CNT piezo nanocomposite: Micromechanical modeling and Monte Carlo simulation

A phenomenological study is carried out to speculate the statistical impacts of the CNT/polymer interphase on the overall electro-elastic behavior of piezo-polymer nanocomposites by presenting a full-field micromechanical model. The nanocomposite system consists of carbon nanotube (CNT) and PVDF. Various statistical distributions, including Weibull, log-normal, normal, beta, and uniform distributions on the thickness and strength of the interphase are carefully assessed. The results are compared with experimental data, and satisfactory agreements are reported. It is found that, compared to the random distribution of the interphase strength, the statistical distribution of the interphase thickness has more effect on the overall electro-elastic properties. For example, for the effective longitudinal modulus, the overall coefficients of variation are 14 %, 13 %, 13.56, and 10 %, respectively, for the normal, Weibull, beta, and uniform distributions of the thickness compared with the measured experimental values. Also, the effects of the CNT content, aspect ratio, and orientation on the effective electro-elastic properties by considering the various random distributions are fully examined. Moreover, using the Monte Carlo simulation, the probability of not meeting design specification (failure probability) is evaluated at the random distributions of the interphase strength and thickness to identify the optimum CNT content for which the values of the overall properties are maximum. It is obtained that the failure probabilities are different for 5–8 % CNT volume fraction in the distributions of the thickness, and for only 5 VF% CNT in the strength distributions. For other values of the CNT content, the failure probabilities are independent of the distribution of the interphase strength and thickness.

ИССЛЕДОВАНИЕ КАЧЕСТВЕННЫХ ПОКАЗАТЕЛЕЙ ОЦЕНКИ ПУНКТИРНО–ГНЕЗДОВОГО СПОСОБА ПОСЕВА

The key factors influencing the yield are the method of sowing, adherence to the set seeding rate and the accuracy of seed placement on the field surface. One of the promising sowing methods is dotted-nesting, when using it, the distance between seeds in a row initially differs, and the mathematical expectation of this distance is different from zero, which limits the use of the coefficient of variation as an indicator of the quality of the seeder. The purpose of the study is to determine the method for assessing the quality indicators of the operation of the sowing machine with the dotted-nested sowing method. Seeding discs with the following design parameters: the number of holes in the seeding disc - 54 pieces, the number of holes in the group - 3 pieces, the angle between the holes in the group - α=5°, the angle between the groups - β=10° were made for experimental studies. The rotational speed of the sowing disc varied from 15 rpm to 60 rpm. used: General and dynamic coefficients of variation, accuracy was used to determine the criterion for assessing the quality of the dotted-nested method of sowing. When determining the dynamic coefficient of variation, a calculation was made every 200 seeds, which, taking into account the seeding rate (20 pcs./m), corresponds to 10 meters of the path traveled by the sowing unit, the obtained values were compared with the theoretical one (0.355). The accuracy of the dotted-nested sowing method was determined by counting the number of seeds in a group, the distance between seeds and the distance to the next group of seeds. If the number of seeds did not correspond to the specified one (k=3) or the interval between seeds exceeded the standard error, then this group of seeds was rejected. Accuracy was calculated as a percentage of "correct nests" to their total number. The overall coefficient of variation did not exceed 2.9% compared to the theoretical one. However, considering the change in the coefficient of variation in dynamics, we found that the difference between theoretical and experimental reaches a maximum of 3.2% at 15 rpm and 7.9% at 40 rpm. The trend towards an increase in the coefficient of variation and a decrease in the accuracy of dotted-nested sowing with an increase in the frequency of rotation of the sowing disk was observed in all the studied variants.

Reliability and clinical utility of a novel telehealth-based goniometry approach to measure range of motion of the digits of the hand

BackgroundRange of motion (ROM) is an outcome measure commonly used when treating acute and chronic hand injuries and conditions. Increased adoption of telehealth service provision in hand therapy practice, influenced by the advent of COVID-19, has led to the need for a valid and reliable approach to measure the range of motion of the digits of the hand when providing hand therapy services using telehealth. PurposeTo determine if performing manual goniometry during a livestream teleconsultation is reliable and clinically useful to measure the range of motion of the fifth digit when providing hand therapy services using telehealth. Study DesignClinical measurement, repeated-measures study. MethodsAccording to a measurement protocol, 12 independent raters (who currently provide hand therapy services) each obtained several screen-based goniometric range of motion measurements of the fifth digit at 2-time points. Raters were surveyed on the clinical utility of the telehealth-based goniometry approach. Measures of relative and absolute reliability were calculated to evaluate test-retest and inter-rater reliability. Free-text responses were analyzed using content analysis. ResultsInter-rater reliability was excellent for all flexion and extension measures (intraclass correlation coefficient [ICC] ≥ 0.89) but poor for the arc of motion (ICC ≤ 0.67). Test-retest reliability was poor (ICC ≤ 0.43). No statistically significant differences between test and retest measurements were observed (P ≥ 0.24). The overall coefficient of variation indicated good precision (14.69%). Measurement error (≤6.07º) and limits of agreement (≤6.33) had acceptable levels to support clinical use. Content analysis revealed several practical considerations. ConclusionsThis study suggests that performing manual goniometry during a livestream teleconsultation is unreliable for measuring the range of motion of the fifth digit. However, when combined with patient-reported and functional outcomes, this approach may be suitable to facilitate a range of motion assessment for certain functions of telehealth service provision in hand therapy practice.

Simplified Models for Composite Elastic Behavior of Precast Concrete Insulated Wall Panels

This paper outlines a new simplified method for predicting the degree of composite action (percent composite) and thus the elastic moment of inertia and the elastic section modulus for precast concrete insulated wall panels. This simplified approach was developed by using 1 million simulations from the iterative sandwich beam theory method. The overall bias (average ratio) of the linear approximation on the simulated test dataset is 1.0 for both cracking and deflection, and the overall coefficient of variation (COV) is 0.04 for cracking and 0.03 for deflection. When compared with data from previously published experiments, the new method has a bias of 1.02 and COV of 0.32 in cases where the experiment conforms to the assumptions of the new method. By comparison, the reported biases of other available methods, which are more complicated to use, range from 0.97 to 1.06, and the COVs of other available methods range from 0.16 to 0.32. Thus, the level accuracy of the new method to predict the percent composite is similar to the levels of accuracy of the more complicated approaches.

Remote sensing evaluation of Chinese mainland's comprehensive natural resources carrying capacity and its spatial-temporal variation characteristics

With the rapid economy development and population growth, China is facing a pressure on the high demand in natural resources. However, most of the natural resource carrying capacity (NRCC) studies considered only on a single natural element, and the data sources showed some limitations. The traditional assessment approach is difficult to provide a comprehensive level of natural resources rapidly for China. Therefore, this study aims to develop a multiple factors NRCC assessment framework by using both remote sensing (RS) satellite data and Geographic Information System (GIS) and to explain the distribution characteristics and spatial-temporal variation characteristics of NRCC from multiple perspectives. The impacts of natural and anthropogenic factors on NRCC in mainland China from 2003 to 2019 were analyzed. The results show that most of the provinces are on an upward trend in the NRCC changes and is significantly higher in the eastern part than in the western part of mainland China. The areas with rapid and significant changes are mainly distributed at the junction of Shaanxi and Shanxi. The overall coefficient of variation of the study area is 0.09, with stable changes, but the stability is worse in the unused land distribution area. The analysis of influencing factors showed that precipitation and temperature were positively correlated with NRCC. The positive correlation was stronger in the regions of bad NRCC, unused land, and grassland. The NRCC values decreased significantly with the increasing elevation. In addition, there was a significant positive correlation between NRCC and human activity pressure from the provincial analysis. This study provides a relatively complete framework for regional natural resource evaluation, which is conducive to promoting sustainable development in mainland China and can effectively evaluate the results of natural resources conservation work and provide effective suggestions for the next step of restoration work.

Development and Validation of an Efficient and Highly Sensitive Enzyme-Linked Immunosorbent Assay for Alemtuzumab Quantification in Human Serum and Plasma.

Alemtuzumab is a humanized monoclonal antibody that targets the CD52 glycoprotein expressed on most lymphocytes, subsequently inducing complement-mediated and antibody-mediated cytotoxicity. Owing to its ability to induce profound immune depletion, alemtuzumab is frequently used in patients before allogeneic hematopoietic stem cell transplantation to prevent graft rejection and acute graft-versus-host disease. In this clinical context, a stable immunoassay with high sensitivity and specificity to determine alemtuzumab levels is essential for performing pharmacokinetic and pharmacodynamic analyses; however, the available methods have several limitations. Here, we report the successful development and validation of an efficient and highly sensitive enzyme-linked immunosorbent assay technique based on commercially available reagents to quantify alemtuzumab in human serum or plasma. This enzyme-linked immunosorbent assay technique was developed and validated in accordance with the European Medicines Agency guidelines on bioanalytical method validation. The assay sensitivity (lower limit of quantification) is 0.5 ng·mL -1 , and the dynamic range is 0.78-25 ng·mL -1 . To accommodate quantification of peak concentration and concentrations below the lympholytic level (<0.1 mcg·mL -1 ), patients' serum samples were prediluted 20-400 times according to the expected alemtuzumab concentration. The overall within-run accuracy was between 96% and 105%, whereas overall within-run precision (coefficient of variation) was between 3% and 9%. The between-run assessment provided an overall accuracy between 86% and 95% and an overall coefficient of variation between 5% and 14%. The developed assay provides accurate insight into alemtuzumab exposure and its effects on the clinical response to treatment, which is key to optimizing treatment strategies.

Feasibility of utilizing radiochromic nickel complex gel for radiation processing

A radiation-sensitive nickel nitrate complex gel was prepared in three concentrations, and dosimetric characteristics were investigated for routine use in gamma radiation processing. Nickel nitrate hexahydrate/Gelatin/1,5-diphenylcarbazone (Ni/G/DPCO) gel demonstrated a maximum wavelength of 535 nm and linear dose-response of 10–1300 Gy. By increasing the absorbed dose, the Ni/G/DPCO gel has a visual color change from purple to colorless. The dose rate dependence on the gel sensitivity at 1.17 and 0.062 Gy/s dose rates was less than 10% difference at a linear dose range of 10–1300 Gy. Color stability before and after irradiation was up to 35 days, and the overall coefficient of variation, CV%, was found to be 3.87%. Hence, the observations proved that the gel has favorable characteristics for food irradiation, insect population control, and irradiation of agricultural products.

MR Fingerprinting for Liver Tissue Characterization: A Histopathologic Correlation Study.

Background Liver MR fingerprinting (MRF) enables simultaneous quantification of T1, T2, T2*, and proton density fat fraction (PDFF) maps in single breath-hold acquisitions. Histopathologic correlation studies are desired for its clinical use. Purpose To compare liver MRF-derived metrics with separate reference quantitative MRI in participants with diffuse liver disease, evaluate scan-rescan repeatability of liver MRF, and validate MRF-derived measurements for histologic grading of liver biopsies. Materials and Methods This prospective study included participants with diffuse liver disease undergoing MRI from July 2021 to January 2022. Participants underwent two-dimensional single-section liver MRF and separate reference quantitative MRI. Linear regression, Bland-Altman plots, and coefficients of variation were used to assess the bias and repeatability of liver MRF measurements. For participants undergoing liver biopsy, the association between mapping and histologic grading was evaluated by using the Spearman correlation coefficient. Results Fifty-six participants (mean age, 59 years ± 15 [SD]; 32 women) were included to compare mapping techniques and 23 participants were evaluated with liver biopsy (mean age, 52.7 years ± 12.7; 14 women). The linearity of MRF with reference measurements in participants with diffuse liver disease (R2 value) for T1, T2, T2*, and PDFF maps was 0.86, 0.88, 0.54, and 0.99, respectively. The overall coefficients of variation for repeatability in the liver were 3.2%, 5.5%, 7.1%, and 4.6% for T1, T2, T2*, and PDFF maps, respectively. MRF-derived metrics showed high diagnostic performance in differentiating moderate or severe changes from mild or no changes (area under the receiver operating characteristic curve for fibrosis, inflammation, steatosis, and siderosis: 0.62 [95% CI: 0.52, 0.62], 0.92 [95% CI: 0.88, 0.92], 0.97 [95% CI: 0.96, 0.97], and 0.74 [95% CI: 0.57, 0.74], respectively). Conclusion Liver MR fingerprinting provided repeatable T1, T2, T2*, and proton density fat fraction maps in high agreement with reference quantitative mapping and may correlate with pathologic grades in participants with diffuse liver disease. © RSNA, 2022 Online supplemental material is available for this article.

Changing Characteristics of Pharmaceutical Prices in China Under Centralized Procurement Policy: A Multi-Intervention Interrupted Time Series.

Objective: National centralized drug procurement organized by the Chinese government currently represents the largest group purchasing organization worldwide, to establish a reasonable price formation mechanism. This study aimed to evaluate the effects of centralized procurement policy on drug price and price ratio in China. Method: Monthly drug procurement data of public medical institutions were extracted from the national procurement database, including 11 pilot cities and 36 months from January 2018 to December 2020. Centralized procured INNs (International Nonproprietary Names) (n = 25) and their alternative INNs (n = 96) were selected as study samples. Centralized procured INNs were divided into bid-winning and non-winning products according to the bidding results. Drug price, price distribution, and price ratio were measured. Multi-intervention interrupted time series analysis was performed to estimate the policy impacts in two centralized procurement periods. Results: The price of centralized procured INNs showed an immediate drop of 44.57% (β = -0.59, p < 0.001) at the policy implementation, among which bid-winning drugs decreased by 61.71% (β = -0.96, p < 0.001). No significant change in the price level or trends was found for non-winning products and alternative drugs in the first-year procurement period (all p-values > 0.05). During the second-year procurement period, alternative drugs in four therapeutic categories detected significant increases in the price level (all p-values < 0.05). The overall coefficient of variation of price distribution exhibited upward trends after policy implementation. Among the most centralized procured INNs, the price ratio between certificated generics (generics that have passed the consistency evaluation) and original drugs declined significantly after policy intervention (p < 0.05), whereas the price ratio between uncertificated and certificated generics increased significantly (p < 0.05). Conclusion: Chinese government-organized group purchasing resulted in prominent price reduction of bid-winning drugs. The policy observed a short-term “spillover” effect of synergistic price reduction, while the effect wore off after 1-year procurement period. The extremely dispersed price distribution, as well as unreasonable price ratios, requires further effective price regulation means.

External quality assessment scheme for HbA1c assays in Thailand: A 5-year experience

BackgroundThailand National External Quality Assessment Scheme (NEQAS) for HbA1c was established to evaluate the quality of HbA1c assays in Thailand in 2016. MethodsHbA1c results from participating laboratories were compared to the target value assigned by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference system. ResultsThe pass rates of participating laboratories during 2016–2020 were72–88%. The mean bias ranged between −0.19 and 0.20% of HbA1c. SD ranged from 0.30 to 1.08% of HbA1c. The overall coefficients of variation ranged from 4.46-15.66%. ConclusionsPerformance evaluation using IFCC assigned values indicated that different assay methods had an effect on HbA1c results. Participation in external quality assessment programs for HbA1c analysis is essential for improving laboratory quality and benefiting patient management.

Reliability and Accuracy of a Time-Efficient Method for the Assessment of Achilles Tendon Mechanical Properties by Ultrasonography.

The assessment of the force–length relationship under mechanical loading is widely used to evaluate the mechanical properties of tendons and to gain information about their adaptation, function, and injury. This study aimed to provide a time-efficient ultrasound method for assessing Achilles tendon mechanical properties. On two days, eleven healthy young non-active adults performed eight maximal voluntary isometric ankle plantarflexion contractions on a dynamometer with simultaneous ultrasonographic recording. Maximal tendon elongation was assessed by digitizing ultrasound images at rest and at maximal tendon force. Achilles tendon stiffness index was calculated from the ratio of tendon force-to-strain. No within- and between-day differences were detected between the proposed method and manual frame by frame tracking in Achilles tendon maximal force, maximal elongation, maximal strain, and stiffness index. The overall coefficient of variation between trials ranged from 3.4% to 10.3% and average difference in tendon tracking between methods was less than 0.6% strain. Furthermore, an additional assessment demonstrated significant differences between elite athletes, healthy young, and older adults in Achilles tendon force and stiffness index. Hence, the analysis has the potential to reliably and accurately monitor changes in Achilles tendon mechanical properties due to aging and altered mechanical loading in a time-efficient manner.

Quantification of major allergens in peach based on shotgun proteomics using liquid chromatography-tandem mass spectrometry

In recent years, reports of peach-related allergies have increased worldwide. Thus, it is necessary to establish an accurate qualitative and quantitative detection method of peach allergen. In this study, a precise qualitative and quantitative method was developed for the detection of peach allergen based on liquid chromatography-tandem mass spectrometry-multiple reaction monitoring (LC-MS/MS-MRM). Eight biomarker peptides of three peach allergen proteins were mined, and one quantitative peptide was screened for each of the three peach allergen proteins, separately. The developed assay provides good linearity (R2 > 0.99) in the concentration range of 0.4–2000 fmol/μL, and the overall coefficient of variation (CV) was under 5% in multiple tests. Limits of detection (LOD) and limits of quantification (LOQ) for the absolute quantification (AQUA) of three peach allergen peptides ranged from 0.4 to 200.0 fmol/μL and 1.6–800 fmol/μL, respectively. The recovery rates were between 90% and 105%. This method achieves accurate qualitative and quantitative detection of three peach allergen proteins in processing food simultaneously, and it may be used to enhance the safety of peach products and reduce the occurrence of allergenic reactions caused by peaches.

Ultrasonic-assisted extraction and automated determination of catalase and lipase activities in bovine and poultry livers using a digital movie-based flow-batch analyzer

An ultrasonic reactor (UR) was developed and coupled to a digital movie-based flow-batch analyzer (DM-FBA) for the ultrasonic-assisted extraction (UAE) and fast determination of catalase and lipase activities in bovine and poultry livers. The lab-made UR mainly consisted of a borosilicate glass container and a piezoelectric disc. The DM-FBA mainly consisted of a webcam, an ultrasonic actuator controller, a peristaltic pump, six solenoid valves, a valve driver, a mixing chamber, a magnetic stirrer, an Arduino Mega 2560, and a personal computer. This setup, named UR-DM-FBA, was controlled by custom software. Ultrasound (US) frequency, US power, sonication time, and concentration of extraction agent were optimized using the Taguchi method. Experiments at silent conditions (mechanical stirring at 1500 rpm) were carried out to evaluate extraction efficiency. Optimized parameters for the UAE of catalase were US frequency of 30 kHz, 2.0 mL of Triton X-100, sonication time of 270 s, and US power of 10.8 W. For the UAE of lipase, the optimized parameters were US frequency of 20 kHz, 0.30 mL of triethanolamine, sonication time of 270 s, and US power of 18 W. Catalase and lipase activities obtained with the UR were, on average, 1.9 × 103% and 2.0 × 103% higher than those obtained at silent conditions, respectively, which indicates that that the lab-made UR was capable of extracting these enzymes more efficiently. Determinations using the UR-DM-FBA were highly accurate (relative error ranging from −1.98% to 1.96% for bovine catalase, −0.65% to 0.76% for bovine lipase, −2.03 to 2.08% for poultry catalase, and −0.55% to 0.64% for poultry lipase) and precise (overall coefficient of variation <0.02% for bovine and poultry catalase and <0.2% for bovine and poultry lipase). Results obtained with the proposed system and reference methods were in good agreement according to the paired t-test (95% confidence level). High sampling rates (>69 h−1) and low sample/reagent consumption (<1.6 mL) were also obtained. Due to the highly efficient UAE, the proposed system can be applied for fast and accurate quantification of lipase and catalase in biological samples with low waste generation.

Light Absorption Measurement With a CMOS Biochip for Quantitative Immunoassay Based Point-of-Care Applications.

We present a CMOS biochip-based photometer for quantitative immunoassay diagnostics. The photometer quantifies the concentration of antigens based on light absorption, which allows for a low-cost implementation without expensive optical components. We propose a light controller to lower the start-up and settling time of the light source to 30 seconds, to facilitate fast measurement starts, and to decrease the overall measurement times. The application-specific integrated circuit (ASIC) contains a 6 x 7-sensor array with 100 μm x 100 μm photodiodes that serve as signal transducers. The ASIC was developed in a normal 0.35- μm CMOS technology, avoiding the need for expensive post-CMOS processes. We present our strategy for the assembly of the ASIC and the immobilization of antibodies. For its first time, we demonstrate the quantification of prostate specific antigen (PSA) with an optoelectronic CMOS biochip using this approach. A PSA immunoassay is performed on the top surface of the CMOS sensor array, enzyme kinetics and PSA concentration are measured within 6 minutes with a limit of detection (LoD) of 0.5 ng/ml, which meets clinical testing requirements. We achieve an overall coefficient of variation (CV) of 7%, which is good compared to other point-of-care (PoC) systems.

Soil Water Deficit and Fertilizer Placement Effects on Root Biomass Distribution, Soil Water Extraction, Water Use, Yield, and Yield Components of Soybean [Glycine max (L.) Merr.] Grown in 1-m Rooting Columns.

Typical small-pot culture systems are not ideal for controlled environment phenotyping for drought tolerance, especially for root-related traits. We grew soybean plants in a greenhouse in 1-m rooting columns filled with amended field soil to test the effects of drought stress on water use, root growth, shoot growth, and yield components. There were three watering treatments, beginning at first flower: watered daily to 100% of the maximum soil water holding capacity (control), 75% (mild drought stress), or 50% (drought stress). We also tested whether applying fertilizer throughout the 1-m soil depth instead of only in the top 30 cm would modify root distribution by depth in the soil profile and thereby affect responses to drought stress. Distributing the fertilizer over the entire 1-m soil depth altered the root biomass distribution and volumetric soil water content profile at first flower, but these effects did not persist to maturity and thus did not enhance drought tolerance. Compared to the control (100%) watering treatment, the 50% watering treatment significantly reduced seed yield by 40%, pod number by 42%, seeds per pod by 3%, shoot dry matter by 48%, root dry matter by 53%, and water use by 52%. Effects of the 75% watering treatment were intermittent between the 50 and 100%. The 50% treatment significantly increased root-to-shoot dry matter ratio by 23%, harvest index by 17%, and water-use efficiency by 7%. Seed size was not affected by either fertilizer or watering treatments. More than 65% of the total root dry matter was distributed in the upper 20 cm of the profile in all watering treatments. However, the two drought stress treatments, especially the mild drought stress, had a greater proportion of root dry matter located in the deeper soil layers. The overall coefficient of variation for seed yield was low at 5.3%, suggesting good repeatability of the treatments. Drought stress imposed in this culture system affected yield components similarly to what is observed in the field, with pod number being the component most strongly affected. This system should be useful for identifying variation among soybean lines for a wide variety of traits related to drought tolerance.