Coefficient Of Variation Range Research Articles

Reliability of bounce drop jump parameters within elite male rugby players.

The aims of the study were to investigate the number of familiarization sessions required to establish reliability of the bounce drop jump (BDJ) and subsequent reliability once familiarization is achieved. Seventeen trained male athletes completed 4 BDJs in 4 separate testing sessions. Force-time data from a 20 cm BDJ was obtained using two force plates (ensuring ground contact <250 ms). Subjects were instructed to "jump for maximal height and minimal contact time" while the best and average of four jumps were compared. A series of performance variables were assessed in both eccentric and concentric phases including jump height, contact time, flight time, Reactive Strength Index (RSI), peak power, rate of force development (RFD) and actual dropping height (ADH). Reliability was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CV) while familiarization was assessed using a repeated-measures analysis of variance (ANOVA). The majority of DJ parameters exhibited excellent reliability with no systematic bias evident, while the average of 4 trials provided greater reliability. With the exception of vertical stiffness (CV: 12.0%) and RFD (CV: 16.2%), all variables demonstrated low within subject variation (CV range: 3.1-8.9%). Relative reliability was very poor for ADH, with heights ranging from 14.87-29.85 cm. High levels of reliability can be obtained from the BDJ with the exception of vertical stiffness and RFD, however, extreme caution must be taken when comparing DJ results between individuals and squads due to large discrepancies between actual drop height and platform height.

Repeatability of apparent diffusion coefficient and intravoxel incoherent motion parameters at 3.0 Tesla in orbital lesions

ObjectivesTo evaluate repeatability of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) parameters in the orbit.MethodsFrom December 2015 to March 2016, 22 patients were scanned twice using an IVIM sequence with 15b values (0–2,000 s/mm2) at 3.0T. Two readers independently delineated regions of interest in an orbital mass and in different intra-orbital and extra-orbital structures. Short-term test-retest repeatability and inter-observer agreement were assessed using the intra-class correlation coefficient (ICC), the coefficient of variation (CV) and Bland-Altman limits of agreements (BA-LA).ResultsTest-retest repeatability of IVIM parameters in the orbital mass was satisfactory for ADC and D (mean CV 12% and 14%, ICC 95% and 93%), poor for f and D*(means CV 43% and 110%, ICC 90% and 65%). Inter-observer repeatability agreement was almost perfect in the orbital mass for all the IVIM parameters (ICC = 95%, 93%, 94% and 90% for ADC, D, f and D*, respectively).ConclusionsIVIM appeared to be a robust tool to measure D in orbital lesions with good repeatability, but this approach showed a poor repeatability of f and D*.Key Points• IVIM technique is feasible in the orbit.• IVIM has a good–acceptable repeatability of D (CV range 12–25 %).• IVIM interobserver repeatability agreement is excellent (ICC range 90–95 %).• f or D* provide higher test-retest and interobserver variabilities.

Metabolic intratumor heterogeneity of breast cancer.

e23095 Background: Breast tumors are highly heterogeneous due to subpopulations of cancer cells that differ in genetic and phenotypic characteristics. Tumor heterogeneity has been associated with treatment resistance and relapse. Therefore, it can be questioned how representative one biopsy is for the whole tumor. Tumor phenotypic heterogeneity cannot be solely attributed to genetic differences, as epigenetics and interaction with the tumor microenvironment also contribute. In this study we have examined intra-tumor heterogeneity by measuring metabolite expression in breast cancer tissue compared with fibroadenomas. Methods: Fresh frozen tissue slices from surgically removed breast tumors were used. Five cores from different areas of the slices were drilled out from 10 tumors; 6 invasive ductal carcinomas grade 2-3, and 4 fibroadenomas. Histological examination of HES-stained sections from each core was done, and metabolic profiling was performed by magnetic resonance spectroscopy (MRS). The relative concentrations of 23 metabolites were quantified. Metabolic heterogeneity was assessed by coefficient of variation (CoV) and PLSDA classification was used for prediction of tumor origin. Results: Cancer tissue showed significantly higher heterogeneity than fibroadenomas for 16/23 metabolites (mean CoV range: 0.15-0.94 for cancer samples, 0.09-0.37 for fibroadenomas, p &lt; 0.05). However, 23/50 samples did not contain tumor tissue on histological examination. After exclusion of tumor-free samples, the heterogeneity of 3 metabolites (glycine, glycerophosphocholine (GPC) and phosphocholine (PCho) remained significantly different between cancer and fibroadenomas (mean CoV range: 0.12-0.65 for cancer, 0.07-0.42 for fibroadenomas, p &lt; 0.05). GPC and PCho are involved in building of cell membranes and may reflect cell-turnover. Multivariate classification could correctly predict which patient a sample belonged to with 78% accuracy. Conclusions: Metabolic heterogeneity could partly be explained by differences in tumor cell and stromal content, and the origin of an unknown sample could be successfully predicted, showing that metabolic intratumor heterogeneity is smaller than the heterogeneity between patients.

Validation of a multi-analyte panel with cell-bound complement activation products for systemic lupus erythematosus

BackgroundWe describe the analytical validation of an assay panel intended to assist clinicians with the diagnosis of systemic lupus erythematosus (SLE). The multi-analyte panel includes quantitative assessment of complement activation and measurement of autoantibodies. MethodsThe levels of the complement split product C4d bound to erythrocytes (EC4d) and B-lymphocytes (BC4d) (expressed as mean fluorescence intensity [MFI]) are measured by quantitative flow cytometry, while autoantibodies (inclusive of antinuclear and anti-double stranded DNA antibodies) are determined by immunoassays. Results of the multi-analyte panel are reported as positive or negative based on a 2-tiered index score. Post-phlebotomy stability of EC4d and BC4d in EDTA-anticoagulated blood is determined using specimens collected from patients with SLE and normal donors. Three-level C4 coated positive beads are run daily as controls. Analytical validity is reported using intra-day and inter-day coefficient of variation (CV). ResultsEC4d and BC4d are stable for 2days at ambient temperature and for 4days at 4°C post-phlebotomy. Median intra-day and inter-day CV range from 2.9% to 7.8% (n=30) and 7.3% to 12.4% (n=66), respectively. The 2-tiered index score is reproducible over 4 consecutive daysupon storage of blood at 4°C. A total of 2,888 three-level quality control data were collected from 6 flow cytometers with an overall failure rate below 3%. Median EC4d level is 6 net MFI (Interquartile [IQ] range 4-9 net MFI) and median BC4d is 18 net MFI (IQ range 13-27 net MFI) among 86,852 specimens submitted for testing. The incidence of 2-tiered positive test results is 13.4%. ConclusionWe have established the analytical validity of a multi-analyte assay panel for SLE.

Evaluation of consumer monitors to measure particulate matter

Recently, inexpensive (<$300) consumer aerosol monitors (CAMs) targeted for use in homes have become available. We evaluated the accuracy, bias, and precision of three CAMs (Foobot from Airoxlab, Speck from Carnegie Mellon University, and AirBeam from HabitatMap) for measuring mass concentrations in occupational settings. In a laboratory study, PM2.5 measured with the CAMs and a medium-cost aerosol photometer (personal DataRAM 1500, Thermo Scientific) were compared to that from reference instruments for three aerosols (salt, welding fume, and Arizona road dust, ARD) at concentrations up to 8500µg/m3. Three of each type of CAM were included to estimate precision. Compared to reference instruments, mass concentrations measured with the Foobot (r-value = 0.99) and medium-cost photometer (r-value=0.99) show strong correlation, whereas those from the Speck (r-value range 0.91-0.99) and AirBeam (0.7–0.96) were less correlated. The Foobot bias was (−12%) for ARD and measurements were similar to the medium-cost instrument. Foobot bias was (<−46%) for salt and welding fume aerosols. Speck bias was at 18% for ARD and −86% for welding fume. AirBeam bias was (−36%) for salt and (−83%) for welding fume. All three photometers had a bias (<−82%) for welding fume. Precision was excellent for the Foobot (coefficient of variation range: 5–8%) and AirBeam (2–9%), but poorer for the Speck (8–25%). These findings suggest that the Foobot, with a linear response to different aerosol types and good precision, can provide reasonable estimates of PM2.5 in the workplace after site-specific calibration to account for particle size and composition.

Test-retest reliability of a 16.1 km time trial in trained cyclists using the CompuTrainer ergometer

Laboratory based cycling time trials (TT) are widely used by both researchers and practitioners, as a method of assessing cycling performance in a controlled environment. Assessments of performance often use TT durations or distances between 20 min and one hour and in the UK the 10 mile (16.1 km) TT is the most frequently used race distance for trained cyclists. The 16.1 km TT has received relatively minimal, but increased attention as a performance criterion in the literature. Therefore, the aim of this study was to assess the reliability of 16.1 km TT performance in a large cohort of trained cyclists using the CompuTrainer cycling ergometer. Trained male cyclists (n = 58, mean±SD age 35±7 yr, height 179±6 cm, weight 79.1±9.4 kg, VO2max. 56.6±6.6 ml.kg.min-1, PPO 365±37 W) performed an initial incremental exercise test to determine PPO and VO2max. The participants then performed two 16.1 km TT on a CompuTrainer cycle ergometer separated by 3-7 days. Differences in time, power output and speed were determined using a Wilcoxon signed ranks or paired t-tests. Reproducibility of the TT performance measures was performed using the coefficient of variation (CV), intraclass correlations, and typical error (TE). There were no differences between any of the performance criteria for the whole cohort (Mean difference = 0.06 min, 0.09 km.h-1, 1.5 W, for time, mean speed and power respectively) between TT1 and TT2. All TT performance data were very reproducible (CV range = 1.1-2.7%) and demonstrated trivial or small TE. The slower cyclists demonstrated marginally lower reliability (CV range = 1.3-3.2%) compared to the fastest group (CV range = 0.7-2.0%). The 16.1 km TT on the CompuTrainer represents a very reliable performance criterion for trained cyclists. Interpretation of test-retest performance outcomes should be performed in the context of the TE of each performance indicator.

Consistency of Field-Based Measures of Neuromuscular Control Using Force-Plate Diagnostics in Elite Male Youth Soccer Players.

Read, P, Oliver, JL, Croix, MD, Myer, GD, and Lloyd, RS. Consistency of field-based measures of neuromuscular control using force-plate diagnostics in elite male youth soccer players. J Strength Cond Res 30(12): 3304-3311, 2016-Deficits in neuromuscular control during movement patterns such as landing are suggested pathomechanics that underlie sport-related injury. A common mode of assessment is measurement of landing forces during jumping tasks; however, these measures have been used less frequently in male youth soccer players, and reliability data are sparse. The aim of this study was to examine the reliability of a field-based neuromuscular control screening battery using force-plate diagnostics in this cohort. Twenty-six pre-peak height velocity (PHV) and 25 post-PHV elite male youth soccer players completed a drop vertical jump (DVJ), single-leg 75% horizontal hop and stick (75%HOP), and single-leg countermovement jump (SLCMJ). Measures of peak landing vertical ground reaction force (pVGRF), time to stabilization, time to pVGRF, and pVGRF asymmetry were recorded. A test-retest design was used, and reliability statistics included change in mean, intraclass correlation coefficient, and coefficient of variation (CV). No significant differences in mean score were reported for any of the assessed variables between test sessions. In both groups, pVGRF and asymmetry during the 75%HOP and SLCMJ demonstrated largely acceptable reliability (CV ≤ 10%). Greater variability was evident in DVJ pVGRF and all other assessed variables, across the 3 protocols (CV range = 13.8-49.7%). Intraclass correlation coefficient values ranged from small to large and were generally higher in the post-PHV players. The results of this study suggest that pVGRF and asymmetry can be reliably assessed using a 75%HOP and SLCMJ in this cohort. These measures could be used to support a screening battery for elite male youth soccer players and for test-retest comparison.

Comparison of reliability and repeatability of corneal curvature assessment with six keratometers

BackgroundKeratometric methodology varies between instruments and the differences may have a clinical impact. We investigated the agreement and reproducibility of six keratometers.MethodsKeratometry was performed on 100 subjects at two separate sessions with IOLMaster 500, Pentacam, OPD scanner, Medmont E300, Javal‐Schiøtz and TMS‐5. A second observer assessed 30 subjects to determine inter‐observer variability. A single individual was assessed on 10 separate sessions to determine intra‐observer variability. Data were analysed using coefficient of variation (CV) and intra‐class correlation coefficient (ICCC) for intra‐observer variation. Inter‐observer concordance was evaluated by the ICCC. Bland–Altman plots, Pearson's correlation coefficient and repeated measures analysis of variance were used to assess agreement of data produced by the instruments.ResultsOPD scanner and Javal‐Schiøtz mean spherical equivalent (MSE) results were systematically different (p < 0.001) from other instruments (flatter and steeper, respectively). J0/J45 were similar for all instruments (p < 0.05). Bland–Altman comparison plots indicated that Pentacam and IOLMaster demonstrated greatest level of agreement (ICC results MSE = 0.992, J0 = 0.934 and J45 = 0.890). Agreement (ICC) between observers for MSE ranged from 0.955 to 0.995 for all instruments; lower levels of agreement were found for J0/J45 (0.289 to 0.901). IOLMaster showed greatest correlation and Medmont the lowest. All instruments showed high intra‐observer repeatability of MSE (CV 0.1 to 0.3 per cent). The J0/J45 readings showed greater variability (CV range 8.8 to 57.6 per cent).ConclusionWhen considering MSE alone IOLMaster, Pentacam, OPD scan and Medmont may be considered interchangeable; however, assessment of astigmatism shows greater variability between instruments, sessions and observers.

Mechanical Player Load™ using trunk-mounted accelerometry in football: Is it a reliable, task- and player-specific observation?

ABSTRACTThe aim of the present study was to examine reliability and construct convergent validity of Player Load™ (PL) from trunk-mounted accelerometry, expressed as a cumulative measure and an intensity measure (PL · min–1). Fifteen male participants twice performed an overground football match simulation that included four different multidirectional football actions (jog, side cut, stride and sprint) whilst wearing a trunk-mounted accelerometer inbuilt in a global positioning system unit. Results showed a moderate-to-high reliability as indicated by the intra-class correlation coefficient (0.806–0.949) and limits of agreement. Convergent validity analysis showed considerable between-participant variation (coefficient of variation range 14.5–24.5%), which was not explained from participant demographics despite a negative association with body height for the stride task. Between-task variations generally showed a moderate correlation between ranking of participants for PL (0.593–0.764) and PL · min–1 (0.282–0.736). It was concluded that monitoring PL® in football multidirectional actions presents moderate-to-high reliability, that between-participant variability most likely relies on the individual’s locomotive skills and not their anthropometrics, and that the intensity of a task expressed by PL · min–1 is largely related to the running velocity of the task.

Short-term reliability of inflammatory mediators and response to exercise in the heat

ABSTRACTProspective application of serum cytokines, lipopolysaccharide (LPS), and heat shock proteins (eHSPs) requires reliable measurement of these biomarkers that can signify exercise-induced heat stress in hot conditions. To accomplish this, both short-term (7 day) reliability (at rest, n = 12) and the acute responsiveness of each biomarker to exercise in the heat (pre and post 60-min cycling, 34.5°C and 70% RH, n = 20) were evaluated. Serum was analysed for the concentration of C-reactive protein (CRP), interleukin-6 (IL-6), heat shock protein 72 (eHSP72), immunoglobulin M (IgM) and LPS. Test–retest reliability was determined as the coefficient of variation (CV). Biomarkers with the least short-term within-participant variation were IL-6 (19%, ±20%; CV, ±95% confidence limits (CL)) and LPS (23%, ±13%). Greater variability was observed for IgM, eHSP72 and CRP (CV range 28–38%). IL-6 exhibited the largest increase in response to acute exercise (95%, ±11%, P = < 0.001) and although CRP had a modest CV (12%, ±7%), it increased substantially post-exercise (P = 0.02, ES; 0.78). In contrast, eHSP72 and LPS exhibited trivial changes post-exercise. It appears variation of common inflammatory markers after exercise in the heat is not always discernible from short-term (weekly) variation.

SU‐F‐J‐103: Assessment of Liver Tumor Contrast for Radiation Therapy: Inter‐Patient and Inter‐Sequence Variability

Purpose:To determine the variation in tumor contrast between different MRI sequences and between patients for the purpose of MRI‐based treatment planning.Methods:Multiple MRI scans of 11 patients with cancer(s) in the liver were included in this IRB‐approved study. Imaging sequences consisted of T1W MRI, Contrast‐Enhanced T1W MRI, T2W MRI, and T2*/T1W MRI. MRI images were acquired on a 1.5T GE Signa scanner with a four‐channel torso coil. We calculated the tumor‐to‐tissue contrast to noise ratio (CNR) for each MR sequence by contouring the tumor and a region of interest (ROI) in a homogeneous region of the liver using the Eclipse treatment planning software. CNR was calculated (I_Tum‐I_ROI)/SD_ROI, where I_Tum and I_ROI are the mean values of the tumor and the ROI respectively, and SD_ROI is the standard deviation of the ROI. The same tumor and ROI structures were used in all measurements for different MR sequences. Inter‐patient Coefficient of variation (CV), and inter‐sequence CV was determined. In addition, mean and standard deviation of CNR were calculated and compared between different MR sequences.Results:Our preliminary results showed large inter‐patient CV (range: 37.7% to 88%) and inter‐sequence CV (range 5.3% to 104.9%) of liver tumor CNR, indicating great variations in tumor CNR between MR sequences and between patients. Tumor CNR was found to be largest in CE‐T1W (8.5±7.5), followed by T2W (4.2±2.4), T1W (3.4±2.2), and T2*/T1W (1.7±0.6) MR scans. The inter‐patient CV of tumor CNR was also the largest in CE‐T1W (88%), followed by T1W (64.3%), T1W (56.2%), and T2*/T1W (37.7) MR scans.Conclusion:Large inter‐sequence and inter‐patient variations were observed in liver tumor CNR. CE‐T1W MR images on average provided the best tumor CNR. Efforts are needed to optimize tumor contrast and its consistency for MRI‐based treatment planning of cancer in the liver.This project is supported by NIH grant: 1R21CA165384

TU-FG-209-04: Testing of Digital Image Receptors Using AAPM TG-150's Draft Recommendations - Investigating the Impact of Different Processing Parameters

Purpose: To evaluate implementation of AAPM TG-150's draft recommendations via a parameter study for testing the performance of digital image receptors. Methods: Flat field images were acquired from 9 calibrated digital image receptors associated with 9 new portable digital radiography systems (Carestream Health, Inc.) based on the draft recommendations and manufacturer-specified calibration conditions (set of 4 images at input detector air kerma ranging from 1 to 25 µGy). Effects of exposure response function (linearized and logarithmic), ‘Presentation Intent Type’ (‘For Processing’ and ‘For Presentation’), detector orientation with respect to the anode-cathode axis (4 orientations; 900 rotations per iteration), different ROI sizes (5×5–40×40 mm2) and elimination of varying dimensions of image border (0 mm i.e., without boundary elimination to 150 mm) on signal, noise, signal-to-noise ratio (SNR) and the associated nonuniformities were evaluated. Images were analyzed in Matlab and quantities were compared using ANOVA. Results: Signal, noise and SNR values averaged over 9 systems with default parameter values in draft recommendations were 4837.2±139.4, 19.7±0.9 and 246.4±10.1 (mean ± standard deviation), respectively (at input detector air kerma: 12.5 µGy). Signal, noise and SNR showed characteristic dependency on exposure response function and on ‘Presentation Intent Type’. These values were not affected by ROI size and detector orientation, but analysis showed that eliminating the edge pixels along the boundary was required for the noise parameter (coefficient of variation range for noise: 72%–106% and 3%–4% without and with boundary elimination; respectively). Local and global nonuniformities showed a similar dependence on the need for boundary elimination. Interestingly, computed non-uniformities showed agreement with manufacturer-reported values except for noise non-uniformities in two units; artifacts were seen in images from these two units highlighting the importance of independent evaluations. Conclusion: The effect of different parameters on performance characterization of digital image receptors was evaluated based on TG-150's draft recommendations.

W5″ Test: A simple method for measuring mean power output in the bench press exercise

The aims of the present study were to assess the validity and reliability of a novel simple test [Five Seconds Power Test (W5″ Test)] for estimating the mean power output during the bench press exercise at different loads, and its sensitivity to detect training-induced changes. Thirty trained young men completed as many repetitions as possible in a time of ≈5 s at 25%, 45%, 65% and 85% of one-repetition maximum (1RM) in two test sessions separated by four days. The number of repetitions, linear displacement of the bar and time needed to complete the test were recorded by two independent testers, and a linear encoder was used as the criterion measure. For each load, the mean power output was calculated in the W5″ Test as mechanical work per time unit and compared with that obtained from the linear encoder. Subsequently, 20 additional subjects (10 training group vs. 10 control group) were assessed before and after completing a seven-week training programme designed to improve maximal power. Results showed that both assessment methods correlated highly in estimating mean power output at different loads (r range: 0.86–0.94; p < .01) and detecting training-induced changes (R2: 0.78). Good to excellent intra-tester (intraclass correlation coefficient (ICC) range: 0.81–0.97) and excellent inter-tester (ICC range: 0.96–0.99; coefficient of variation range: 2.4–4.1%) reliability was found for all loads. The W5″ Test was shown to be a valid, reliable and sensitive method for measuring mean power output during the bench press exercise in subjects who have previous resistance training experience.

Variation in crystalloid administration: an analysis of 6248 patients undergoing major elective surgery

BackgroundLarge variations exist regarding the type and volume of fluid to be administered to patients. This study aimed to quantitate variations in the administration of crystalloid fluids at the level of the patient, provider, and procedure at a large, tertiary care center. MethodPatients who underwent major cardiac, thoracic, or abdominal procedures between 2011 and 2014 were identified. Variations in crystalloid administration were compared by procedure and provider using a coefficient of variation (CV). Multivariable hierarchical linear modeling was performed to identify factors predictive of fluid administration and quantitate variation at the level of the patient and provider. ResultsAmong 6248 patients who met inclusion criteria, the average crystalloid volume was 25.8 mL kg−1 m2 h−1, corresponding to a CV of 55%. Patients who underwent pancreatectomy received the highest corrected crystalloid volume (32.7 mL kg−1 m2 h−1), whereas those who underwent coronary artery bypass grafting received the lowest corrected crystalloid volume (14.7 mL kg−1 m2 h−1). Variations in fluid practices were noted between providers (corrected CV; 14.7%-97.1%) and within the practices of the same provider (corrected CV range; 24.1%-87.9%). On multivariable analysis, age and changes in hemoglobin concentration were associated with a higher crystalloid volume (both P < 0.05). Although over 90% of the variation was attributed to patient-level factors, approximately 10% was due to factors at level of the provider (surgeon: 5.8% versus anesthesiologist: 3.4%). ConclusionsWide variations were noted in crystalloid administration between procedures, providers, and within providers. Evidence-based practices and goal-directed therapies should be incorporated to avoid unwanted variations.

Sperm membrane integrity in fresh and frozen–thawed canine semen samples: a comparison of vital stains with the NucleoCounter SP-100

The objective of this study was to assess sperm membrane integrity in canine semen samples using three different vital stains and the NucleoCounter SP-100 (NC). In addition, the occurrence of half-stained sperm heads, the influence of investigator, and storage-related artifacts using stained smears were examined. Forty fresh (30 dogs) and 40 frozen–thawed (28 dogs) canine semen samples were analyzed. The vital stains eosin (E), eosin-nigrosin (EN), and bromphenolblue-nigrosin (BN) were compared. Two smears per stain were prepared and a total of 200 sperm per slide were classified using bright field microscopy. Each slide was examined twice by three investigators. Spermatozoa with completely red (E, EN) or blue (BN) stained sperm heads were classified as “dead”. Half-stained sperm heads were counted separately. Sperm concentration and viability were determined using the NC. The NC works with a built-in fluorescence microscope using propidium iodide as a fluorescence dye. Statistical analysis for comparison of results was made using mean values with standard deviation, Bland-Altman plot and coefficient of variation (CV). Staining with E led to a significant higher percentage of dead sperm compared with EN and BN (P < 0.05), which gave comparable results. Vital stains revealed higher CVs (range 8.8%–32.1%) than the NC (<6.5%). Interobserver viability ranged from 17.5% to 45.4% and was within the same range between stains. If only completely stained sperm heads were considered, best agreement was found between the E and the NC. In case of EN and BN, inclusion of half-stained sperm heads reduced the difference compared with NC. In general, the agreement between methods was better in samples with a low percentage of dead spermatozoa. In smears of fresh semen stored up to 3 months, no increase in the percentage of dead spermatozoa could be observed. In some smears of frozen–thawed samples stained with E (n = 12) or BN (n = 2), all previously unstained spermatozoa were additionally stained during storage. In conclusion, all vital stains examined in this study technically can be used for differentiation between live and dead spermatozoa in canine semen samples, but the relatively high CVs have to be kept in mind. It is recommended to examine smears of frozen–thawed semen soon after preparation. Half-stained sperm heads should be counted as live sperm in E-stained smears. The NC allows assessment of sperm concentration and viability with a reasonable repeatability.

Toxicity tests using the kelp Undaria pinnatifida for heavy metal risk assessment

The toxicity of six metals (Cd, Cu, Hg, Ni, Pb and Zn) to the early life stages of the brown seaweed Undaria pinnatifida were tested using two endpoints: spore germination and germ tube elongation. The optimal test conditions determined for photon irradiance, pH, salinity and temperature were darkness, pH 8, 35‰ and 15°C, respectively. The EC50 values could be determined only for Hg and Cu and were 27 μg · L-1 and 186 μg · L-1, respectively, for germination and 16 μg · L-1 and 45 μg · L-1, respectively, for germ tube elongation. The variability of our U. pinnatifida test in response to the metal toxicants, as estimated from the coefficient of variation of the mean EC50 values, was less than 28%. When tested against two different wastewater samples (PCB manufacturer and TV & communication equipment manufacturer), U. pinnatifida exhibited an EC50 of 66.09-80.73% for germination and 24.98-62.62% for germ tube elongation with the CV (Coefficient of variation) range for both germination and germ tube elongation between 1.24 and 13.18%. The novel aspect of the present method is that the testing procedure requires no lighting or photoperiodic control. Additionally, the response of Undaria to the toxicity of Hg and Cu is very similar to that reported for other very sensitive macroalgal species. Because of its ecological and economic importance, the evaluation of toxicity using early stages of U. pinnatifida will provide useful scientific information, and we propose that this represents a valid bioassay within the battery of aquatic bioassays for the assessment of anthropogenic impacts on coastal ecosystems and commercial cultivation areas in nearshore environments.

Comparison among monitoring strategies to assess water flow dynamic and soil hydraulic properties in agricultural soils

Irrigated agriculture is usually performed in semi-arid regions despite scarcity of water resources. Therefore, optimal irrigation management by monitoring the soil is essential, and assessing soil hydraulic properties and water flow dynamics is presented as a first measure. For this purpose, the control of volumetric water content, θ, and pressure head, h, is required. This study adopted two types of monitoring strategies in the same experimental plot to control θ and h in the vadose zone: i) non-automatic and more time-consuming; ii) automatic connected to a datalogger. Water flux was modelled with Hydrus-1D using the data collected from both acquisition strategies independently (3820 daily values for the automatic; less than 1000 for the non-automatic). Goodness-of-fit results reported a better adjustment in case of automatic sensors. Both model outputs adequately predicted the general trend of θ and h, but with slight differences in computed annual drainage (711 mm and 774 mm). Soil hydraulic properties were inversely estimated from both data acquisition systems. Major differences were obtained in the saturated volumetric water content, θs, and the n and α van Genuchten model shape parameters. Saturated hydraulic conductivity, Ks, shown lower variability with a coefficient of variation range from 0.13 to 0.24 for the soil layers defined. Soil hydraulic properties were better assessed through automatic data acquisition as data variability was lower and accuracy was higher.

Intravoxel Incoherent Motion Diffusion-weighted MR Imaging of the Liver: Effect of Triggering Methods on Regional Variability and Measurement Repeatability of Quantitative Parameters

To compare the influence of triggering methods for diffusion-weighted imaging (DWI) on apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM) parameters in the liver, as well as regional variability and measurement repeatability. In this institutional review board-approved prospective study, 12 healthy volunteers (six women, six men; mean age, 30 years) underwent 1.5-T DWI of the liver by using nine b values twice with free breathing (FB) without triggering (mean acquisition time ± standard deviation, 3.7 minutes ± 0), respiratory triggering (RT) (mean acquisition time, 6.8 minutes ± 1.4), and echocardiography triggering (ET) (mean acquisition time, 8.3 minutes ± 2.0) after providing written informed consent. ADC and IVIM parameters, including pure diffusion coefficient (D), perfusion fraction (f), and perfusion-related diffusion coefficient (D*), were measured by using 15 regions of interest (ROIs). Regional variability of ADC and IVIM parameters and measurement repeatability were evaluated by using the coefficient of variation (CV) across ROIs and within-subject CV, respectively. ET DWI (range of CV across ROIs, 6.69%-20.0%) resulted in significantly decreased regional variability of ADC, D, and f, compared with FB DWI (13.86%-35.8%) and RT DWI (15.15%-35.91%, P ≤. 049). ET DWI showed better repeatability of ADC measurement (within-subject CV range, 3.17%-4.12% for ET DWI; 4.15%-4.74% for FB DWI; and 2.33%-6.96% for RT DWI), D (4.05%-5.34% for ET DWI, 4.11%-12.51% for FB DWI, and 3.19%-16.17% for RT DWI), and f (7.6%-9.86% for ET DWI, 13.83%-16.81% for FB DWI, and 10.05%-12.10% for RT DWI), compared with FB DWI and RT DWI, with significant differences in within-subject CV for D in the left hepatic lobe compared with RT DWI (P = .023) and for f compared with FB DWI (P ≤ .032). For all three imaging techniques, D* showed the worst repeatability (within-subject CV, 57.05%-156.61%) among ADC and IVIM parameters. ET DWI is more effective for decreasing regional variability of ADC and IVIM parameters than FB DWI or RT DWI; it may improve measurement repeatability by reducing cardiac motion-induced measurement error.

Quantitative Proteomic Analysis of Microdissected Breast Cancer Tissues: Comparison of Label-Free and SILAC-based Quantification with Shotgun, Directed, and Targeted MS Approaches

Quantitative proteomics plays an important role in validation of breast-cancer-related biomarkers. In this study, we systematically compared the performance of label-free quantification (LFQ) and SILAC with shotgun and directed methods for quantifying breast-cancer-related markers in microdissected tissues. We show that LFQ leads to slightly higher coefficient of variation (CV) for protein quantification (median CV = 16.3%) than SILAC quantification (median CV = 13.7%) (P < 0.0001), but LFQ method enables ∼60% more protein quantification and is also more reproducible (∼20% more proteins were quantified in all replicate samples). Furthermore, we describe a method to accurately quantify multiple proteins within one pathway, that is, "focal adhesion pathway", in trace amounts of breast cancer tissues using a SILAC-based SRM assay. Using this SILAC-based SRM assay, we precisely quantified five "focal adhesion" proteins with good quantitative precision (CV range: 2.4-5.9%) in replicate whole tissue lysate samples and replicate microdissected samples (CV range: 5.8-16.1%). Our results show that in microdissected breast cancer tissues LFQ in combination with shotgun proteomics performed the best overall and is therefore suitable for both biomarker discovery and validation in these types of specimens. The SILAC-based SRM method can be used for the development of clinically relevant protein assays in tumor biopsies.

Inter- and intra-session reliability of muscle activity patterns during cycling

The aim of this study was to determine the inter- and intra-session reliability of the temporal and magnitude components of activity in eight muscles considered important for the leg cycling action. On three separate occasions, 13 male non-cyclists and 11 male cyclists completed 6min of cycling at 135, 150, and 165W. Cyclists completed two additional 6-min bouts at 215 and 265W. Surface electromyography was used to record the electrical activity of tibialis anterior, soleus, gastrocnemius medialis, gastrocnemius lateralis, vastus medialis, vastus lateralis, rectus femoris, and gluteus maximus. There were no differences (P>0.05) in the muscle activity onset and offset or in the iEMG of any muscles between visits. There were also no differences (P>0.05) between cyclists and non-cyclists in the variability of these parameters. Overall, standard error of measurement (SEM) and intra-class correlation analyses suggested similar reliability of both inter- and intra-session muscle activity onset and offset. The SEM of activity onset in tibialis anterior and activity offset in soleus, gastrocnemius lateralis and rectus femoris was markedly higher than in the other muscles. Intra-session iEMG was reliable (coefficient of variation (CV)=5.3–13.5%, across all muscles), though a CV range of 15.8–43.1% identified low inter-session iEMG reliability. During submaximal cycling, the temporal components of muscle activity exhibit similar intra- and inter-session reliability. The magnitude component of muscle activity is reliable on an intra-session basis, but not on an inter-session basis.