Search results for "Calibration"
showing 10 items of 890 documents
Determining the location of the body׳s center of mass for different groups of physically active people
2013
The purpose of the present study was to compare the location of the body center of mass (CoM) determined by using a high accuracy reaction board (RB) and two different segment parameter models for motion analysis (Dempster, 1955, DEM and de Leva, 1996 adjusted from Zatsiorsky and Seluyanov, ZAT). The body CoM (expressed as percentage of the total body height) was determined from several subjects including athletes as well as physically active students and sedentary people. Some significant differences were found in the location of the body CoM between the used segment models and the reaction board method for all male subjects (n=58, 57.03±0.79%, 56.20±0.76% and 57.60±0.76% for RB, ZAT and D…
Automated Determination of Dextromethorphan and Its Main Metabolites in Human Plasma by High-Performance Liquid Chromatography and Column Switching
1996
An automated column-switching technique coupled to isocratic high-performance liquid chromatography (HPLC) with fluorescence detection was developed for simultaneous determination of dextromethorphan and its three major metabolites, dextrorphan, hydroxymorphinan, and methoxymorphinan. After cleavage of conjugates by incubation with glucuronidasearylsulfatase at 37 degrees C for 15 h, plasma samples were injected directly into the HPLC system. Dextromethorphan and metabolites were retained on a cleanup column (10 x 4.6 mm internal diameter [ID]) filled with cyanopropyl (CN) material (Hypersil CPS, 10-microns article size) while interfering proteins and lipids were washed to waste. After colu…
Detection of gamma-hydroxybutyrate in hair: Validation of GC–MS and LC–MS/MS methods and application to a real case
2012
A gas chromatography-mass spectrometry (GC-MS) and a liquid chromatography tandem mass spectrometry (LC-MS/MS) method were validated for quantifying endogenous and exogenous hair concentrations of gamma-hydroxybutyrate (GHB). The GC-MS method is based on overnight extraction of 25 mg hair in NaOH at 56 °C, liquid/liquid extraction in ethylacetate and trimethylsylil derivatization; analysis is by electron ionization and single ion monitoring of three ions. The LC-MS/MS method entails a rapid digestion of 25 mg hair with NaOH at 75 °C for 40 min, liquid/liquid extraction in ethylacetate and reconstitution of the extract in the LC mobile phase; negative ion electrospray ionization and multiple…
Reference Values for a Homogeneous Ferritin Assay and Traceability to the 3rd International Recombinant Standard for Ferritin (NIBSC Code 94/572)
1999
Abstract Reference values for two ferritin assays (Tina-quant®a Ferritin, Enzymun®, both Roche Diagnostics, Mannheim, Germany) were established (136 males and 139 females). To rule out inflammation as well as iron deficiency in the reference population, subjects with the C-reactive protein concentration < 5 mg/l, and zinc protoporphyrin < 40 µmol/mol heme and the soluble transferrin receptor < 3 mg/l were selected. Taking into account latent iron deficiency as well as hereditary hemochromatosis the 5–95 percentile range was as follows: male, 27–365 μg/l; female, 13–148 μg/l for Tina-quant®a and 12–151 μg/l for Enzymun®. The Tinaquant® a Ferritin assay showed a very good correlation…
Frameless Neuronavigation Applied to Endoscopic Neurosurgery
2000
Objective: We retrospectively analyzed the indications, surgical techniques, and applicability of frameless neuronavigation to endoscopic procedures in a heterogeneous group of 15 patients. Material and Methods: In 8 patients indications for surgery were cystic lesions, in 3 patients intraventricular tumors, and in 4 patients occlusive hydrocephalus. The mean age was 39 years (range 9 - 76 years). The follow-up period ranged from 5 - 24 months (mean 10 months). Frameless neuronavigation was accomplished with the “operating arm system” in 10 cases and with the “optical tracking system” in 5 cases (RADIONICS, Burlington, USA). Results: In all 15 cases, neuronavigation sufficiently provided an…
Monocular Versus Binocular Calibrations in Evaluating Fixation Disparity With a Video-Based Eye-Tracker
2015
When measuring fixation disparity (an oculomotor vergence error), the question arises as to whether a monocular or binocular calibration is more precise and physiologically more appropriate. In monocular calibrations, a single eye fixates on a calibration target that is taken as having been projected onto the center of the fovea; the corresponding vergence state represents the heterophoria (the resting vergence position), which has no effect on the calibration procedure. In binocular calibrations, a vergence error may be present and may affect the subsequent measurement of the fixation disparity during binocular recordings. This study includes a test of the precision of both monocular and …
Accuracy of magnetic resonance enterography in the preoperative assessment of patients with Crohn's disease of the small bowel
2016
Aim to assess the accuracy of magnetic resonance-enterography in predicting the extension, location and characteristics of the small bowel segments affected by Crohn's disease. Method This is a prospective study including a consecutive series of 38 patients with small bowel Crohn's disease who underwent surgery at a specialized colorectal unit of a tertiary hospital. Preoperative magnetic resonance enterography was performed in all patients, following a homogeneous protocol, within the three months prior to surgery. A thorough exploration of the small bowel was performed during the surgical procedure, using calibration spheres, according to the discretion of the surgeon. The accuracy of mag…
Inability of Laplace's law to estimate sub-bandage pressures after applying a compressive bandage: a clinical study
2021
Objective: The aim of the current study was to compare pressures exerted on the lower limb by a high compression bandage as recorded by sub-bandage sensors and those estimated by Laplace's law. The correlation between pressures obtained in each anatomical zone and the corresponding limb perimeters were explored. Method: For the measurement of sub-bandage pressures, four anatomical zones in the lower right limb were determined. Pressures were recorded by nine pneumatic sensors and a PicoPress transducer. A two-layer compression bandage system (UrgoK2, Urgo Group, France) was used for the dressing. Pressures were registered in supine position. Sensor pressures were compared with those estimat…
A minimal limit-cycle model to profile movement patterns of individuals during agility drill performance: Effects of skill level.
2015
Identification of control strategies during agility performance is significant in understanding movement behavior. This study aimed at providing a fundamental mathematical model for describing the motion of participants during an agility drill and to determine whether skill level constrained model components. Motion patterns of two groups of skilled and unskilled participants (n = 8 in each) during performance of a forward/backward agility drill modeled as limit-cycles. Participant movements were recorded by motion capture of a reflective marker attached to the sacrum of each individual. Graphical and regression analyses of movement kinematics in Hooke’s plane, phase plane and velocity prof…
External validation of a prognostic model estimating the survival of patients with recurrent high-grade gliomas after reirradiation
2015
PURPOSE: We aimed to validate a controversial prognostic model for the survival of relapsed malignant glioma patients after reirradiation with an independent, multicentric patient cohort.METHODS AND MATERIALS: A total of 165 malignant glioma patients underwent reirradiation at 4 different institutions between 1994 and 2012. Twenty-two patients had a good (score 1), 44 had a moderate (score 2), and 99 had a poor prognosis (score 3 or 4). Four statistical methods were used to validate the prognostic model: First, we compared survival according to prognostic group in the construction and the validation cohort by visual comparison of the respective Kaplan-Meier plots. Second, discrimination was…