Individual Coefficient Of Variation Research Articles

The impact of marker selection, in-line near-infrared spectroscopy (NIR), and feed mix time on the coefficient of variation (mix uniformity), body weight uniformity and broiler growth performance during the starter, grower, and finisher periods

Most feed manufacturers in the United States use the same mixing time (and thus mix uniformity) throughout the growing period regardless of age and consumption patterns. However, research evaluating the optimum mixing time requirements and novel analysis methods, such as in-line near-infrared (NIR) spectroscopy, on the coefficient of variation (CV) and growth performance of broilers throughout the production phases is sparse. Two experiments were conducted to determine the effects of marker selection, in-line NIR, and varying mix times on mix uniformity, broiler growth performance, and body weight uniformity from 1 to 42 d of age. Feed was manufactured utilizing a 1,815-kg counterpoise ribbon mixer. In both experiments, feed was mixed for 4.5 min (3 min dry mix and 90 s of wet mix) and 30 s (0 s dry mix and 30 s wet mix) to obtain a standard mix (SM) and an abbreviated mix (AM), respectively. Experiment 1 constituted a 2×2×4 factorial arrangement of 2 mix times, (4.5 and 0.5 min), 2 batch sizes (908 and 1,815 kg), and 4 methodologies to evaluate mixer performance (sodium chloride, Microtracers (Red#40 and Blue#40), and in-line NIR). In experiment 2, broilers received different mix time combinations: 1) SM from 1 to 42 d, 2) SM from 1 to 28 d and AM from 28 to 42 d, 3) SM from 1 to 14 d and AM from 14 to 42 d, and 4) AM from 1 to 42 d. In both experiments, selecting a single source marker provided a more accurate estimation of mixer CV in SM and AM diets (P < 0.05). In experiment 2, mix time did not influence BW, feed intake (FI), FCR, or individual bird BW CV from 1 to 42 d of age (P > 0.05). These data indicated that mixer CV differed depending on total mix time and methodology used and diets with a reduced mix time may not necessarily influence growth performance and BW uniformity during the starter, grower, and finisher periods of broilers.

Quantification of spinal ataxia in dogs with thoracolumbar spinal cord injury.

The clinical sign of ataxia is related to several neurological diseases and is seen in conjunction with paresis in dogs with spinal cord injury (SCI). Endeavours to objectify canine spinal ataxia in SCI remain limited. The aim of this clinical study was to determine and quantify differences between gait characteristics of ataxic dogs with thoracolumbar myelopathy and healthy control dogs using a computer-and treadmill-based gait analysis system. Five dogs with spinal ataxia and six healthy dogs underwent video-and computer-assisted gait analysis while walking on a four-ground reaction force plate treadmill system (maximum speed of 0.7 m/s). Spatio-temporal and kinetic gait characteristics regarding the dogs' locomotion were analysed with a focus on the individual coefficient of variation (CV), as a potential measure for quantification of the level of ataxia. Ataxic dogs with thoracolumbar SCI showed no effect on symmetry indices but higher variability in spatio-temporal and kinetic gait parameters mainly in the pelvic, but also in the thoracic limbs. Double support phase of the individual limb was prolonged in SCI dogs at the cost of the single support and swing phase. Reduced peaks of ground reaction forces (GRF) could potentially be explained by reduction of muscle strength, as a strategy of avoiding falling by taking enthusiastic steps, or by alteration of the rhythmogenic spinal circuits between the pelvic and thoracic limb pattern generators.

Quantification of Cerebral Glucose Concentrations via Detection of the H1-α-Glucose Peak in 1 H MRS at 7 T.

Sensitive detection and quantification of cerebral glucose is desired. To quantify cerebral glucose by detecting the H1-α-glucose peak at 5.23 ppm in 1 H magnetic resonance spectroscopy at 7 T. Prospective. Twenty-eight non-fasted healthy subjects (aged 20-28 years). Short echo time stimulated echo acquisition mode (short-TE STEAM) and semi-localized by adiabatic selective refocusing (semi-LASER) at 7 T. Single voxel spectra were obtained from the posterior cingulate cortex (27-mL) using a 32-channel head coil. The H1-α-glucose peak in the spectrum with retrospective removal of the residual water peak was fitted using LCModel with a glucose basis set of only the H1-α-glucose peak. Conventional spectral analysis was performed with a glucose basis set of a full spectral pattern of glucose, also. Fitting precision was evaluated with Cramér-Rao lower bounds (CRLBs). The repeatability of glucose quantification via the semi-LASER sequence was tested. Paired or Welch's t-test were used for normally distributed values. A P value of <0.05 was considered significant. The repeatability of measures was analyzed using coefficient of variation (CV). Removal of the residual water peak improved the flatness and stability of baselines around the H1-α-glucose peak and reduced CRLBs for fitting the H1-α-glucose peak. The semi-LASER sequence was superior to the short-TE STEAM in the higher signal-to-noise ratio of the H1-α-glucose peak (mean ± SD 7.9 ± 2.5, P < 0.001). The conventional analysis overfitted the H1-α-glucose peak. The individual CVs of glucose quantification by detecting the H1-α-glucose peak were smaller than the corresponding CRLBs. Cerebral glucose concentration is quantitated to be 1.07 mM by detecting the H1-α-glucose peak in the semi-LASER spectra. Despite requiring long scan times, detecting the H1-α-glucose peak allows true glucose quantification free from the influence of overlapping taurine and macromolecule signals. 2 TECHNICAL EFFICACY STAGE: 1.

A robust and readily implementable method for the meta-analysis of response ratios with and without missing standard deviations.

The log response ratio, lnRR, is the most frequently used effect size statistic for meta-analysis in ecology. However, often missing standard deviations (SDs) prevent estimation of the sampling variance of lnRR. We propose new methods to deal with missing SDs via a weighted average coefficient of variation (CV) estimated from studies in the dataset that do report SDs. Across a suite of simulated conditions, we find that using the average CV to estimate sampling variances for all observations, regardless of missingness, performs with minimal bias. Surprisingly, even with missing SDs, this simple method outperforms the conventional approach (basing each effect size on its individual study-specific CV) with complete data. This is because the conventional method ultimately yields less precise estimates of the sampling variances than using the pooled CV from multiple studies. Our approach is broadly applicable and can be implemented in all meta-analyses of lnRR, regardless of 'missingness'.

Impact of protocolized fluid management on electrolyte stability in patients undergoing continuous renal replacement therapy.

ObjectiveContinuous renal replacement therapy (CRRT) is the standard treatment for critically ill patients with acute kidney injury (AKI). Electrolyte disturbance such as hypokalemia or hypophosphatemia occurs paradoxically in patients undergoing CRRT due to high clearance. We developed a fluid management protocol for dialysate and replacement fluid that depends on serum electrolytes and focuses on potassium and phosphate levels to prevent electrolyte disturbance during CRRT. The impact of our new fluid protocol on electrolyte stability was evaluated.MethodsAdult patients who received CRRT between 2013 and 2017 were included. Patients treated 2 years before (2013–2014; pre-protocol group) and 2 years following development of the fluid protocol (2016–2017; protocol group) were compared. The primary outcomes were individual coefficient of variation (CV) and abnormal event rates of serum phosphate and potassium. Secondary outcomes were frequency of electrolyte replacement and incidence of cardiac arrhythmias. Individual CV and abnormal event rates for each electrolyte were analyzed using the Wilcoxon rank-sum test and Chi-square test with Yates’ continuity correction.ResultsA total of 1,448 patients was included. Both serum phosphate and potassium were higher in the protocol group. The CVs of serum phosphate (pre-protocol vs. protocol, 0.275 [0.207–0.358] vs. 0.229 [0.169–0.304], p < 0.01) and potassium (0.104 [0.081–0.135] vs. 0.085 [0.064–0.110], p < 0.01) were significantly lower in the protocol group. The abnormal event rates of serum phosphate (rate [95% CI], 0.410 [0.400–0.415] vs. 0.280 [0.273–0.286], p < 0.01) and potassium (0.205 [0.199–0.211] vs. 0.083 [0.079–0.087], p < 0.01) were also significantly lower in the protocol group.ConclusionThe protocolized management of fluid in CRRT effectively prevented hypophosphatemia and hypokalemia by inducing excellent stability of serum phosphate and potassium levels.

The influence of calculation method and relative strength on the load-velocity relationship in bench press exercise

Purpose The objective of this study was: (1) to compare the effect of the calculation method using average (Avalue), and best value (Bvalue) of Mean Propulsive Velocity (MPV) on the Load Velocity Profile (LVprofile) during the barbell bench press exercise in elite handball players. In addition, (2) to analyze the relationship between the individual coefficient of variation (CVind) of an incremental load protocol in the bench press exercise with relative strength (Frel) in professional handball players. Methods Nineteen elite international handball players (age 18 [±1] y; body mass 93 [±14] kg; height 191 [±6] cm) performed an incremental test during the barbell bench press exercise. General and individual LVprofile, Frel, and CVind were modelled through MPV and two calculation models (Avalue, vs Bvalue). Results There were significant differences (p &lt; 0.05) between both conditions (Bvalue vs. Avalue). There was an inverse relationship between the Frel and the CVind (r = −0.66, p &lt; 0.001). When CVind was &gt;10% significant differences were found between the two calculations method (Avalue, vs Bvalue). However, no significant differences were found between Avalue, vs Bvalue when the CVind was &lt;10%. Conclusions The calculation method used to assess the barbell bench press LVprofile impacts the nature of the relationship. Regardless CVind values, Avalue is a good choice to determine the LVprofile when the CVind is &gt;10%, if the CVind is &lt;10%, Bvalue will be the better option to determine the LVprofile.

Comparative Performance of Four Nucleic Acid Amplification Tests for SARS-CoV-2 Virus.

COVID-19 is caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), which was discovered in 2019 and spread around the world in a short time. SARS-CoV-2 nucleic acid amplification tests (NAATs) have been rapidly developed and quickly applied to clinical testing of COVID-19. Aim of this study was to evaluate the performance of four NAAT assays. Limit of detection (LOD), precision, accuracy, analytical specificity and analytical interference studies on four NAATs (Daan, Sansure, Hybribio, and Bioperfectus) were performed according to Clinical Laboratory Standards Institute protocols and guidelines. The four NAATs were compared using 46 clinical samples. The LOD of the N gene for Daan, Sansure, and Hybribio was 500 copies/mL, and that for Bioperfectus was 1,000 copies/mL. The LOD of the ORF1ab gene for Daan, Bioperfectus, and Hybribio was 3,000 copies/mL, and that for Sansure was 2,000 copies/mL. A good precision was shown at the concentration above 20% of the LOD for all four NAATs, with all individual coefficients of variation below 3.6%. Satisfactory results were also observed in the accuracy, analytical specificity, and analytical interference tests. The results of the comparison test showed that Daan, Sansure, and Hybribio NAATs could detect the samples with a specificity of 100% (30/30) and a sensitivity of 100% (16/16), whereas Bioperfectus NAAT detected the samples with a specificity of 100% (30/30) and a sensitivity of 81.25% (13/16). However, no significant difference in sensitivity was found between Bioperfectus NAAT and the three other NAATs (p > 0.05). The four SARS-CoV-2 NAATs showed comparable performance, with the LOD of the N gene lower than the LOD of the ORF1ab gene.

Variability of Thyroid Measurements from Ultrasound and Laboratory in a Repeated Measurements Study

Background: Variability of measurements in medical research can be due to different sources. Quantification of measurement errors facilitates probabilistic sensitivity analyses in future research to minimize potential bias in epidemiological studies. We aimed to investigate the variation of thyroid-related outcomes derived from ultrasound (US) and laboratory analyses in a repeated measurements study. Subjects and Methods: Twenty-five volunteers (13 females, 12 males) aged 22–70 years were examined once a month over 1 year. US measurements included thyroid volume, goiter, and thyroid nodules. Laboratory measurements included urinary iodine concentrations and serum levels of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), and thyroglobulin. Variations in continuous thyroid markers were assessed as coefficient of variation (CV) defined as mean of the individual CVs with bootstrapped confidence intervals and as intraclass correlation coefficients (ICCs). Variations in dichotomous thyroid markers were assessed by Cohen’s kappa. Results: CV was highest for urinary iodine concentrations (56.9%), followed by TSH (27.2%), thyroglobulin (18.2%), thyroid volume (10.5%), fT3 (8.1%), and fT4 (6.3%). The ICC was lowest for urinary iodine concentrations (0.42), followed by fT3 (0.55), TSH (0.64), fT4 (0.72), thyroid volume (0.87), and thyroglobulin (0.90). Cohen’s kappa values for the presence of goiter or thyroid nodules were 0.64 and 0.70, respectively. Conclusion: Our study provides measures of variation for thyroid outcomes, which can be used for probabilistic sensitivity analyses of epidemiological data. The low intraindividual variation of serum thyroglobulin in comparison to urinary iodine concentrations emphasizes the potential of thyroglobulin as marker for the iodine status of populations.

Discussion on Different Seasonal Variation of Serum Cholesterol in East and West Finland 1956-57 - Milk, Magnesium and Acid Soluble Silicon

Individual coefficient of variation in serum cholesterol values has been reported to be 5-10 % [1]. Sometimes this variation can be higher, especially in East Finland between June1956 and January 1957 [2]. Role of environmental factors is discussed. Inflammation can elevate serum cholesterol and apoB/apoA ratio [3]. TNF-alpha and IL-6 are reported to increase cholesterol synthesis many-fold via elevation activity of HMG-CoA reductase [4].

Repeatability of anterior segment measurements by optical coherence tomography combined with Placido disk corneal topography in eyes with keratoconus

Corneal tomography is an important tool to identify and follow up eyes with keratoconus. Our study evaluate the repeatability of the automatic measurements provided in keratoconic eyes by a new anterior-segment optical coherence tomographer (AS-OCT) combined with Placido-disk topography (MS-39, CSO) and assess their agreement with the corresponding measurements taken with a rotating Scheimpflug camera combined with Placido-disk topography (Sirius, CSO). Mean simulated keratometry, posterior and total corneal power, total corneal astigmatism, corneal asphericity, thinnest corneal thickness, epithelial thickness, corneal diameter, and aqueous depth were evaluated. Repeatability was assessed using test–retest variability, the coefficient of variation, and the intraclass correlation coefficient; agreement was assessed by the 95% limits of agreement. Good repeatability was achieved for most parameters. Moderate repeatability was found for total corneal astigmatism measurements. The repeatability of mean simulated keratometry and total corneal power measurements worsened with more severe stages of keratoconus with a statistically significant relationship between the individual coefficient of variation and corneal power values. Agreement with the Scheimpflug camera was moderate for aqueous depth and thinnest corneal thickness and poor for most other measured parameters. The good repeatability of automatic measurements suggests the new AS-OCT device to be a viable option in clinical practice of eyes with keratoconus.

Community and individual iodine status assessment in premenopausal women in Shanxi, China: Repeated spot urine versus 24-hour urine.

Urinary iodine is an essential index of iodine nutrition evaluation. To establish the number of repeated spot urine collections necessary to reflect individual iodine status over 2 months and assess its feasibility to serve as an independent indicator of individual iodine status. We performed a longitudinal, 2-months study from May to June in 2015 of 23 apparently healthy Chinese women aged 18 to 44 (32±9) y. Spot urine samples were collected on any two days of the week, and 24-h urine samples were collected once every 6 days. 368 spot urine and 230 24-h urine samples were analysed. The median urinary iodine concentration (UIC) was 140.5 (75.2, 246.9) μg/L. The estimated 24-h urinary iodine excretion (24-h UIE) values from spot urine samples and measured 24-h UIE values from 24-h urine samples were 348±240 μg/24h and 330±216 μg/24h (p=0.003), respectively. Irrespective of the urinary iodine method, the intra- individual coefficient of variation (CV%) was lower than the inter-individual CV%. Bland-Altman analysis revealed differences between spot urine and 24-h urine. When the precision ranges with 95% confidence were ±15%, ±20%, ±25% or 30%, the number of an individual's spot urine samples required were 30, 16, 11 or 8, respectively. Repeated spot urine is not a feasible way to assess recent individual iodine intake. The development of a multi-indicator system could provide an acceptable individual evaluation index of iodine status.

Intraoperative Blood Pressure Variability Predicts Postoperative Mortality in Non-Cardiac Surgery-A Prospective Observational Cohort Study.

Little is known about the clinical importance of blood pressure variability (BPV) during anesthesia in non-cardiac surgery. We sought to investigate the impact of intraoperative BPV on postoperative mortality in non-cardiac surgery subjects, taking into account patient- and procedure-related variables. This prospective observational study covered 835 randomly selected patients who underwent gastrointestinal (n = 221), gynecological (n = 368) and neurosurgical (n = 246) procedures. Patient’s and procedure’s risks were assessed according to the validated tools and guidelines. Blood pressure (systolic, SBP, and diastolic, DBP) was recorded in five-minute intervals during anesthesia. Mean arterial pressure (MAP) was assessed. Individual coefficients of variation (Cv) were calculated. Postoperative 30-day mortality was considered the outcome. Median SBP_Cv was 11.2% (IQR 8.4–14.6), DBP_Cv was 12.7% (IQR 9.8–16.3) and MAP_Cv was 10.96% (IQR 8.26–13.86). Mortality was 2%. High SBP_Cv (i.e., ≥11.9%) was associated with increased mortality by 4.5 times (OR = 4.55; 95% CI 1.48–13.93; p = 0.008). High DBP_Cv (i.e., ≥22.4%) was associated with increased mortality by nearly 10 times (OR = 9.73; 95% CI 3.26–28.99; p < 0.001). High MAP_Cv (i.e., ≥13.6%) was associated with increased mortality by 3.5 times (OR = 3.44; 95% CI 1.34–8.83; p = 0.01). In logistic regression, it was confirmed that the outcome was dependent on both SBPV and DBPV, after adjustment for perioperative variables, with AUCSBP_Cv = 0.884 (95% CI 0.859–0.906; p < 0.001) and AUCDBP_Cv = 0.897 (95% CI 0.873–0.918; p < 0.001). Therefore, intraoperative BPV may be considered a prognostic factor for the postoperative mortality in non-cardiac surgery, and DBPV seems more accurate in outcome prediction than SBPV.

Radiomic feature stability across 4D respiratory phases and its impact on lung tumor prognosis prediction.

Radiomic analysis has recently demonstrated versatile uses in improving diagnostic and prognostic prediction accuracy for lung cancer. However, since lung tumors are subject to substantial motion due to respiration, the stability of radiomic features over the respiratory cycle of the patient needs to be investigated to better evaluate the robustness of the inter-patient feature variability for clinical applications, and its impact in such applications needs to be assessed. A full panel of 841 radiomic features, including tumor intensity, shape, texture, and wavelet features, were extracted from individual phases of a four-dimensional (4D) computed tomography on 20 early-stage non-small-cell lung cancer (NSCLC) patients. The stability of each radiomic feature was assessed across different phase images of the same patient using the coefficient of variation (COV). The relationship between individual COVs and tumor motion magnitude was inspected. Population COVs, the mean COVs of all 20 patients, were used to evaluate feature motion stability and categorize the radiomic features into 4 different groups. The two extremes, the Very Small group (COV≤5%) and the Large group (COV>20%), each accounted for about a quarter of the features. Shape features were the most stable, with COV≤10% for all features. A clinical study was subsequently conducted using 140 early-stage NSCLC patients. Radiomic features were employed to predict the overall survival with a 500-round bootstrapping. Identical multiple regression model development process was applied, and the model performance was compared between models with and without a feature pre-selection step based on 4D COV to pre-exclude unstable features. Among the systematically tested cutoff values, feature pre-selection with 4D COV≤5% achieved the optimal model performance. The resulting 3-feature radiomic model significantly outperformed its counterpart with no 4D COV pre-selection, with P = 2.16x10-27 in the one-tailed t-test comparing the prediction performances of the two models.

Data-independent Acquisition Improves Quantitative Cross-linking Mass Spectrometry

Quantitative cross-linking mass spectrometry (QCLMS) reveals structural detail on altered protein states in solution. On its way to becoming a routine technology, QCLMS could benefit from data-independent acquisition (DIA), which generally enables greater reproducibility than data-dependent acquisition (DDA) and increased throughput over targeted methods. Therefore, here we introduce DIA to QCLMS by extending a widely used DIA software, Spectronaut, to also accommodate cross-link data. A mixture of seven proteins cross-linked with bis[sulfosuccinimidyl] suberate (BS3) was used to evaluate this workflow. Out of the 414 identified unique residue pairs, 292 (70%) were quantifiable across triplicates with a coefficient of variation (CV) of 10%, with manual correction of peak selection and boundaries for PSMs in the lower quartile of individual CV values. This compares favorably to DDA where we quantified cross-links across triplicates with a CV of 66%, for a single protein. We found DIA-QCLMS to be capable of detecting changing abundances of cross-linked peptides in complex mixtures, despite the ratio compression encountered when increasing sample complexity through the addition of E. coli cell lysate as matrix. In conclusion, the DIA software Spectronaut can now be used in cross-linking and DIA is indeed able to improve QCLMS.

Multicenter in vitro thromboelastography and thromboelastometry standardization.

To establish and compare the repeatability and reproducibility of activated thromboelastography (TEG) and thromboelastometry (ROTEM) assays. Multicenter in vitro test standardization. Veterinary academic centers. Test samples were obtained from normal, healthy dogs. Sixty identical 5mL aliquots of canine platelet-rich plasma collected by apheresis, frozen in 6% dimethyl sulfoxide, were tested initially. Sixty identical 6mL aliquots of canine fresh frozen plasma with admixed cryoprecipitate were subsequently evaluated. None. Frozen study samples, quality controls, reagents, and consumables were distributed to participating centers (7 TEG and 3 ROTEM). TEG centers analyzed study samples with kaolin and tissue factor activated assays; ROTEM centers ran proprietary ellagic acid activated and tissue factor activated assays. All machines underwent quality control prior to sample analysis. Within- and between-center coefficients of variation (CVs) were calculated and compared using Mann-Whitney tests and calculation of intraclass correlation coefficients. Within and between centers, individual parameters for both TEG and ROTEM assays were comparable. Both within-center and between-center CVs varied markedly (0.7-120.5% and 1.4-116.5%, respectively) with assay type, instrument, and parameter. CVs for equivalent parameters were not significantly different between the 2 platforms. Intraclass correlation coefficients suggested moderate agreement between centers. In general, individual parameter CVs for platelet-rich plasma samples were lower in TEG centers, while CVs for canine fresh frozen plasma with admixed cryoprecipitate samples were lower in ROTEM centers. More variation within and between centers was identified than anticipated, but some parameters such as alpha angle were repeatable and reproducible. Sample types for future multicenter standardization efforts will require further optimization and may need to be adapted separately to each platform. Individual centers using viscoelastic tests for evaluation and management of clinical patients should take steps to minimize preanalytical and analytical sources of variation.

Post-mortem quetiapine concentrations in hair segments of psychiatric patients — Correlation between hair concentration, dose and concentration in blood

Drug analysis in hair is useful when seeking to establish drug intake over a period of months to years. Segmental hair analysis can also document whether psychiatric patients are receiving a stable intake of antipsychotics. This study describes segmental analysis of the antipsychotic drug quetiapine in post-mortem hair samples from long-term quetiapine users by ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) analysis. The aim was to obtain more knowledge on quetiapine concentrations in hair and to relate the concentration in hair to the administered dose and the post-mortem concentration in femoral blood.We analyzed hair samples from 22 deceased quetiapine-treated individuals, who were divided into two groups: natural hair colour and dyed/bleached hair. Two to six 1cm long segments were analyzed per individual, depending on the length of the hair, with 6cm corresponding to the last six months before death. The average daily quetiapine dose and average concentration in hair for the last six months prior to death were examined for potential correlation. Estimated doses ranged from 45 to 1040mg quetiapine daily over the period, and the average concentration in hair ranged from 0.18 to 13ng/mg. A significant positive correlation was observed between estimated daily dosage of quetiapine and average concentration in hair for individuals with natural hair colour (p=0.00005), but statistical significance was not reached for individuals with dyed/bleached hair (p=0.31). The individual coefficient of variation (CV) of the quetiapine concentrations between segments ranged from 3 to 34% for individuals with natural hair colour and 22–62% for individuals with dyed/bleached hair. Dose-adjusted concentrations in hair were significantly lower in females with dyed/bleached hair than in individuals with natural hair colour. The quetiapine concentrations in post-mortem femoral blood and in the proximal hair segment, segment 1 (S1), representing the last month before death were also investigated for correlation. A significant positive correlation was observed between quetiapine concentrations in blood at the time of death and concentrations in S1 for individuals with natural hair colour (p=0.003) but not for individuals with dyed/bleached hair (p=0.31). The blood concentrations of quetiapine ranged from 0.006 to 1.9mg/kg, and the quetiapine concentrations in S1 ranged from 0.22 to 24ng/mg.The results of this study suggest a positive correlation of quetiapine between both concentrations in hair and doses, and between proximal hair (S1) and blood concentrations, when conditions such as hair treatments are taken into consideration.

Multidirectional In Vivo Characterization of Skin Using Wiener Nonlinear Stochastic System Identification Techniques

A triaxial force-sensitive microrobot was developed to dynamically perturb skin in multiple deformation modes, in vivo. Wiener static nonlinear identification was used to extract the linear dynamics and static nonlinearity of the force-displacement behavior of skin. Stochastic input forces were applied to the volar forearm and thenar eminence of the hand, producing probe tip perturbations in indentation and tangential extension. Wiener static nonlinear approaches reproduced the resulting displacements with variances accounted for (VAF) ranging 94-97%, indicating a good fit to the data. These approaches provided VAF improvements of 0.1-3.4% over linear models. Thenar eminence stiffness measures were approximately twice those measured on the forearm. Damping was shown to be significantly higher on the palm, whereas the perturbed mass typically was lower. Coefficients of variation (CVs) for nonlinear parameters were assessed within and across individuals. Individual CVs ranged from 2% to 11% for indentation and from 2% to 19% for extension. Stochastic perturbations with incrementally increasing mean amplitudes were applied to the same test areas. Differences between full-scale and incremental reduced-scale perturbations were investigated. Different incremental preloading schemes were investigated. However, no significant difference in parameters was found between different incremental preloading schemes. Incremental schemes provided depth-dependent estimates of stiffness and damping, ranging from 300 N/m and 2 Ns/m, respectively, at the surface to 5 kN/m and 50 Ns/m at greater depths. The device and techniques used in this research have potential applications in areas, such as evaluating skincare products, assessing skin hydration, or analyzing wound healing.

Variability and reproducibility of carotid structural and functional parameters assessed with transcutaneous ultrasound – Results from the SAPALDIA Cohort Study

ObjectiveCarotid intima media thickness (CIMT) and local stiffness are vascular biomarkers of atherosclerotic burden. We investigated the variability and reproducibility of clinically relevant structural (CIMT, lumen diameter) and functional parameters (strain, distensibility, compliance, β-stiffness index, Peterson's elastic modulus and Young's elastic modulus) measured in B-mode ultrasound sequences of the common carotid artery in the second follow up of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases In Adults (SAPALDIA3). MethodsUltrasound sequential images were examined twice over a 1 cm segment across at least one heart cycle in 165 SAPALDIA3 participants. To assess variability and reproducibility of structural and functional parameters, individual coefficients of variation (CV), intraclass correlation (ICC), Bland–Altman plots and mixed effect regressions were used. ResultsICCs of repeated examinations ranged between 0.67 and 0.77 for blood pressure indices, between 0.87 and 0.97 for structural properties and between 0.75 and 0.79 for functional parameters. CV was lowest in structural parameters (1.6–4.6%), followed by blood pressure (5.1–7.9%) and functional indices (11.0–13.1%). Variations in all parameters were predominantly explained by subjects (>74% in functional, >82% in structural properties). Bland–Altman plots for functional indices showed mean and standard deviation of the respective mean value of 4.2(19.6)% for strain, 1.9(24.4)% for distensibility, 2.4(22.2)% for compliance, 3.0(24.4)% for β-stiffness index, 0.9(25.7)% for Peterson's elastic modulus and 1.2(27.9)% for Young's elastic modulus. ConclusionThe results show that SAPALDIA3 measurements of transcutaneous ultrasound examinations have an excellent reproducibility of structural parameters and a good reproducibility of functional indices.

Vaccination with recombinant Clostridium perfringens toxoids α and β promotes elevated antepartum and passive humoral immunity in swine

Due to the increasingly restricted use of antimicrobials in animal production systems, the prevention and control of Clostridium perfringens type A- and C-induced diarrhea in piglets should be based on passive immunization via the prepartum vaccination of sows. Given the current obstacles in the production of conventional clostridial vaccines, the use of recombinant proteins has been considered to represent a promising alternative. In the present study, the neutralizing antibody response of immunized sows and their litters to a bivalent vaccine containing the C. perfringens recombinant toxoids alpha (rTA) and beta (rTB) produced in Escherichia coli was assessed. Rabbits (n=8) and pregnant sows (n=7) were immunized with 200μg of each recombinant antigen using Al(OH)3 as adjuvant. The alpha and beta antitoxin titer detected in the rabbits’ serum pool was 9.6 and 20.4IU/mL, respectively. The mean alpha and beta antitoxin titers in the sows’ sera were 6.0±0.9IU/mL and 14.5±2.2IU/mL, and the corresponding individual coefficients of variation (CV) were 16.04% and 14.91%, respectively. The mean alpha and beta antitoxin titers in the litters’ serum pools were 4.2±0.4IU/mL and 10.9±1.7IU/mL, and the CV between litters was 9.23% and 9.85%, respectively. The results showed that the rTA and rTB proteins produced and tested in the present study induced an immune response and can be regarded as candidates for the development of a commercial vaccine against C. perfringens type A- and C-induced diarrhea in pigs.

Weight, Age and Coefficients of Variation in Renal Solute Excretion

Background: Homoscedasticity (constant variance over axes or among statistical factors) is an integral assumption of most statistical analyses. However, a number of empirical studies in model organisms and humans demonstrate significant differences in residual variance (that component of phenotype unexplained by known factors) or intra-individual variation among genotypes. Our work suggests that renal traits may be particularly susceptible to randomization by genetic and non-genetic factors, including endogenous variables like age and weight. Methods: We tested associ-ations between age, weight and intra-individual variation in urinary calcium, citrate, chloride, creatinine, potassium, magnesium, sodium, ammonium, oxalate, phosphorus, sulfate, uric acid and urea nitrogen in 9,024 male and 6,758 female kidney stone patients. Coefficients of variation (CVs) were calculated for each individual for each solute from paired 24-hour urines. Analysis of CVs was corrected for inter-measurement collection variance in creatinine and urine volume. CVs for sodium and urea nitrogen were included to correct for dietary salt and protein. Results: Age was positively associated with individual CVs for calcium and negatively associated with CVs for potassium, ammonium and phosphorus (p_FDR < 0.01). Weight was associated with CVs for creatinine, magnesium and uric acid, and negatively associated with CVs for calcium, potassium and oxalate (p_FDR < 0.05). Conclusion: Intra-individual variation changes over age and weight axes for numerous urinary solutes. Changing residual variance over age and weight could cause bias in the detection or estimation of genetic or environmental effects. New methodologies may need to account for such residual unpredictability, especially in diverse collections.