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Coefficient of variation

Hussain Mohamad Awwad, Juergen Geisel, Rima Obeid
BACKGROUND: Trimethylamine-N-oxide (TMAO) is produced in the liver from trimethylamine (TMA) and is an important cellular osmolyte and potential atherogenic factor. Taurine is involved in cholesterol metabolism and also serves as a cellular osmolyte. Given their significant biological functions, the development of reliable measurement techniques is crucial to further study their role in health and disease METHODS: A new ultrahigh performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of TMA, TMAO, and taurine in plasma and urine...
October 15, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Ulrike Herberg, Katharina Linden, Oliver Dewald, Eva Gatzweiler, Matthias Seehase, Georg Daniel Duerr, Jonas Dörner, Stephanie Kleppe, Dennis Ladage, Johannes Breuer
BACKGROUND: Pressure-volume loops (PVL) provide vital information regarding ventricular performance and pathophysiology in cardiac disease. Unfortunately, acquisition of PVL by conductance technology is not feasible in neonates and small children due to the available human catheter size and resulting invasiveness. The aim of the study was to validate the accuracy of PVL in small hearts using volume data obtained by real-time three-dimensional echocardiography (3DE) and simultaneously acquired pressure data...
2016: PloS One
T Shaw, M A Campbell, K C Runions, S R Zubrick
BACKGROUND: Although developed for adults, the Depression Anxiety Stress Scales-Short Version (DASS-21) has been used in many research studies with adolescent samples. Evidence as to the applicability of the DASS subscale scores to represent the distinct states of depression, anxiety, and stress as experienced by adolescents is mixed, and the age at which it may be possible to differentiate these 3 states using the DASS-21 has not yet been determined. OBJECTIVE: This study evaluated evidence for a multifactor structure in the DASS-21 in adolescents and the specificity of the 3 subscales for adolescents in general and at different ages...
October 23, 2016: Journal of Clinical Psychology
Zafer Iscan, Maria Nazarova, Tommaso Fedele, Evgeny Blagovechtchenski, Vadim V Nikulin
Inter- and intra-subject variability of the motor evoked potentials (MEPs) to TMS is a well-known phenomenon. Although a possible link between this variability and ongoing brain oscillations was demonstrated, the results of the studies are not consistent with each other. Exploring this topic further is important since the modulation of MEPs provides unique possibility to relate oscillatory cortical phenomena to the state of the motor cortex probed with TMS. Given that alpha oscillations were shown to reflect cortical excitability, we hypothesized that their power and variability might explain the modulation of subject-specific MEPs to single- and paired-pulse TMS (spTMS, ppTMS, respectively)...
2016: Frontiers in Human Neuroscience
Anupam Priyadarshi, Sandip Mandal, S Lan Smith, Hidekatsu Yamazaki
We develop moment closure approximations to represent micro-scale spatial variability in the concentrations of nutrients (N), phytoplankton (P) and zooplankton (Z) in an NPZ model, which we apply to examine the impact of different levels of micro-scale variability on both ecosystem dynamics and trophic transfer. Accounting explicitly for both the mean-field and fluctuating components of each prognostic variable in the NPZ model yields different dynamics for the mean-field concentrations, as well as lower phytoplankton biomass and greater zooplankton biomass, compared to the conventional NPZ model without micro-scale variability...
October 20, 2016: Journal of Theoretical Biology
Seifollah Gholampour, Nasser Fatouraee, Amir Saeed Seddighi, Afsoun Seddighi
In the present study, the heads of 11 normal subjects and 21 patients affected by hydrocephalus due to three different causes were simulated using fluid-structure interaction (FSI). To validate the results, the calculated diagram of CSF velocity in aqueduct of Sylvius (AS) was compared with the similar velocity diagram measured using Cine PC-MRI for the same subject. After ensuring the agreement of results, other outputs such as CSF pressure were calculated non-invasively using FSI. The intracranial pressure and CSF pressure in AS and behind the optic nerve sheath were in patients 5-5...
October 20, 2016: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
Seyi Latunde-Dada, Rachel Bott, Jack Crozier, Markos Trikeriotis, Oksana Iryna Leszczyszyn, David Goodall
Taylor dispersion analysis (TDA) is an absolute method for determining the diffusion coefficients, and hence the hydrodynamic radii, of particles by measuring the dispersion in a carrier medium flowing within a capillary. It is applicable under conditions which allow the particles to radially diffuse appreciably across the cross-section of the flow before the measurement and therefore implies long measurement times are required for large particles with small diffusion coefficients. In this paper, a method has been developed by which the diffusion coefficients of large particles can be rapidly estimated from the shapes of the concentration profiles obtained at much earlier measurement times...
October 13, 2016: Journal of Chromatography. A
Alex Hayes, Katrina Easton, Pavan Teja Devanaboyina, Jian-Ping Wu, Thomas Brett Kirk, David Lloyd
BACKGROUND: The cross-sectional area (CSA) of a material is used to calculate stress under load. The mechanical behaviour of soft tissue is of clinical interest in the management of injury; however, measuring CSA of soft tissue is challenging as samples are geometrically irregular and may deform during measurement. This study presents a simple method, using structured light scanning (SLS), to acquire a 3D model of rabbit Achilles tendon in vitro for measuring CSA of a tendon. METHOD: The Artec Spider™ 3D scanner uses structured light and stereophotogrammetry technologies to acquire shape data and reconstruct a 3D model of an object...
October 6, 2016: Journal of Biomechanics
Sarthok Sircar, Giang Nguyen, Andrei Kotousov, Anthony J Roberts
A self-consistent model is developed to investigate attachment/detachment kinetics of two static, deformable microspheres with irregular surface and coated with flexible binding ligands. The model highlights how the microscale binding kinetics of these ligands as well as the attractive/repulsive potential of the charged surface affects the macroscale static deformed configuration of the spheres. It is shown that in the limit of smooth, neutrally charged surface (i.e., the dimensionless inverse Debye length, [Formula: see text]), interacting via elastic binders (i...
October 2016: European Physical Journal. E, Soft Matter
Guido Grassi, Gino Seravalle, Gianmaria Brambilla, Raffaella Dell'Oro, Fosca Quarti Trevano, Francesco Fici, Luc van Bortel, Giuseppe Mancia
INTRODUCTION: The present study was aimed at comparing the antihypertensive efficacy, tolerability, and side effects profile of nebivolol/hydrochlorothiazide (NH) vs irbesartan/hydrochlorothiazide (IH) combination in elderly patients with isolated systolic hypertension (ISH). METHODS: 124 ISH patients aged 69.1 ± 5.1 years (mean ± SD) were enrolled by 13 general practitioners in Netherlands and Belgium and randomized in a double-blind fashion to receive either NH (5/12...
October 22, 2016: Advances in Therapy
J M Shiguetomi-Medina, J L Ramirez-Gl, H Stødkilde-Jørgensen, B Møller-Madsen
BACKGROUND: Up to 80 % of cartilage is water; the rest is collagen fibers and proteoglycans. Magnetic resonance (MR) T1-weighted measurements can be employed to calculate the water content of a tissue using T1 mapping. In this study, a method that translates T1 values into water content data was tested statistically. MATERIALS AND METHODS: To develop a predictive equation, T1 values were obtained for tissue-mimicking gelatin samples. 1.5 T MRI was performed using inverse angle phase and an inverse sequence at 37 (±0...
October 22, 2016: Journal of Orthopaedics and Traumatology: Official Journal of the Italian Society of Orthopaedics and Traumatology
Miao Liao, Yu-Qian Zhao, Wei Wang, Ye-Zhan Zeng, Qing Yang, Frank Y Shih, Bei-Ji Zou
Liver segmentation from abdominal computed tomography (CT) volumes is extremely important for computer-aided liver disease diagnosis and surgical planning of liver transplantation. Due to ambiguous edges, tissue adhesion, and variation in liver intensity and shape across patients, accurate liver segmentation is a challenging task. In this paper, we present an efficient semi-automatic method using intensity, local context, and spatial correlation of adjacent slices for the segmentation of healthy liver regions in CT volumes...
October 19, 2016: Physica Medica: PM
Mwlod Ghareeb, Fatemeh Akhlaghi
Tacrolimus is a commonly used immunosuppressive agent in organ transplant recipients. Therapeutic drug monitoring (TDM) of tacrolimus is essential to adjust the dose and achieve optimal immunosuppression level. Routine TDM is practiced using whole blood samples obtained through venipuncture. However, tacrolimus concentration that is present in oral fluid (OF) can theoretically represent the free or pharmacologically active form of tacrolimus. In this study, we report the development and validation of a rapid, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantification of tacrolimus in OF...
October 11, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Tom Kai Ming Wang, Andrew Woodhead, Tharumenthiran Ramanathan, James Pemberton
BACKGROUND: Nearly half of the patients undergoing coronary artery bypass grafting (CABG) have diabetes. There is mixed data as to whether preoperative (haemoglobin A1c{HbA1c}) and/or perioperative diabetes control is associated with mortality and morbidity after CABG. We reviewed the characteristics and outcomes of diabetic patients undergoing CABG with a focus on HbA1c, perioperative glucose levels and diabetic treatment regimens. METHODS: Diabetic patients undergoing CABG during July 2010 to June 2012 were studied (n=306)...
July 4, 2016: Heart, Lung & Circulation
Jie Meng, Lijing Zhu, Li Zhu, Huanhuan Wang, Song Liu, Jing Yan, Baorui Liu, Yue Guan, Yun Ge, Jian He, Zhengyang Zhou, Xiaofeng Yang
BACKGROUND: To explore the role of apparent diffusion coefficient (ADC) histogram shape related parameters in early assessment of treatment response during the concurrent chemo-radiotherapy (CCRT) course of advanced cervical cancers. METHODS: This prospective study was approved by the local ethics committee and informed consent was obtained from all patients. Thirty-two patients with advanced cervical squamous cell carcinomas underwent diffusion weighted magnetic resonance imaging (b values, 0 and 800 s/mm(2)) before CCRT, at the end of 2nd and 4th week during CCRT and immediately after CCRT completion...
October 22, 2016: Radiation Oncology
Margret Thorsteinsdottir, Unnur A Thorsteinsdottir, Finnur F Eiriksson, Hrafnhildur L Runolfsdottir, Inger M Sch Agustsdottir, Steinunn Oddsdottir, Baldur B Sigurdsson, Hordur K Hardarson, Nilesh R Kamble, Snorri Th Sigurdsson, Vidar O Edvardsson, Runolfur Palsson
Adenine phosphoribosyltransferase (APRT) deficiency is a hereditary disorder that leads to excessive urinary excretion of 2,8-dihydroxyadenine (DHA), causing nephrolithiasis and chronic kidney disease. Treatment with allopurinol or febuxostat reduces DHA production and attenuates the renal manifestations. Assessment of DHA crystalluria by urine microscopy is used for therapeutic monitoring, but lacks sensitivity. We report a high-throughput assay based on ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) for quantification of urinary DHA...
September 14, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Manuel Garza-Leon, Hugo A Fuentes-de la Fuente, Ana V García-Treviño
PURPOSE: The purpose of the study was to assess the reproducibility of ocular biometry using the IOLMaster-700 in a healthy population. METHODS: This is a prospective, cross-sectional, observational reproducibility study. Ocular biometry was performed three times on each of 45 studied eyes. Flattest meridian (Kf) and the steepest meridian (Ks), central corneal thickness, axial length, anterior chamber depth, aqueous depth, lens thickness, and white-to-white distances were recorded...
October 21, 2016: International Ophthalmology
Jing Chen, Bao Qiong Li, Min Li Xu, Xue Wang, Yu Hong Jing, Hong Lin Zhai
The interference signals and overlapped peaks are common phenomena in fluorescence determination, which seriously influence the accuracy and reliability of analytical results. In this paper, Krawtchouk image moment method was introduced to the analysis of fluorescence three-dimensional (3D) spectra and applied to the quantitative analysis of three drugs including nicotinic acid, metoprolol and amlodipine in human plasma. Without any pretreatment to the obtained spectra, Krawtchouk moments were directly calculated on the grayscale images of 3D spectra, and the quantitative linear models for the three drugs were established by stepwise regression, respectively...
December 1, 2016: Talanta
Yong Zhao, Xiao Liu, Xiaochen Wang, Chongyun Sun, Xinrui Wang, Pingping Zhang, Jingfu Qiu, Ruifu Yang, Lei Zhou
Contamination of grains and other crops by aflatoxin B1 (AFB1), a highly toxic aflatoxin produced by Aspergillus flavus and Aspergillus parasiticus, poses a serious threat to human health and is an important food safety issue. In this study, a competitive up-converting phosphor technology-based lateral flow (AFB1-UPT-LF) assay was developed for rapid detection of AFB1. Detection sensitivity of the proposed assay can reach 0.03ngmL(-1) for standard AFB1 solutions, with the coefficients of variation (CV) less than 10% (from 1...
December 1, 2016: Talanta
Angelos Hatzakis, Helen Papachristou, Sangeetha J Nair, Jacqueline Fortunko, Tracy Foote, HeeCheol Kim, Tashi L Peling, Andrew J Worlock
BACKGROUND: Quantitation of HIV-RNA is critically important for diagnosis, prognosis, treatment, monitoring and assessment of infectivity in HIV-1 infection. The objective of this study was to assess performance characteristics of the Aptima HIV-1 Quant Dx assay (Aptima), a new transcription mediated amplification (TMA), fully integrated and automated assay from Hologic Inc., San Diego, CA, USA. The analytical sensitivity, analytical specificity, precision and detection of HIV-1 subtypes were tested based on commercially available international standards or panels...
October 21, 2016: Virology Journal
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