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Precise Method (precise + method)
Selected AbstractsQuantification by real-time PCR of the magnitude and duration of leucocyte-associated viraemia in horses infected with neuropathogenic vs. non-neuropathogenic strains of EHV- 1EQUINE VETERINARY JOURNAL, Issue 3 2006G. P. Allen Summary Reasons for performing study: Neurological disease in horses caused by infection with certain ,paralytic' strains of equine herpesvirus-1 (EHV-1) is a potentially devastating condition the pathogenesis of which is poorly understood. Preliminary observations in both experimentally induced and naturally occurring cases of the central nervous system disease have revealed a more robust cell-associated viraemia in horses infected with paralytic isolates of EHV-1, relative to horses infected with abortigenic isolates. To investigate further this pathogenesis - rdevant question, the present study was performed using a greater number of horses and a more precise method for quantification of EHV-1 DNA present in viraemic leucocytes. Objective: To compare the magnitude and duration of leucocyte-associated viraemia in seronegative, age-matched foals following infection with paralytic vs. abortigenic isolates of EHV-1. Methods: Peripheral blood mononuclear cells (PBMC) were collected from 20 weanling foals at 2, 4, 7, 9, 11, 14 and 21 days after intranasal inoculation with either paralytic or abortigenic isolates of EHV-1. The amount of EHV-1 DNA present in each PBMC sample was measured by real-time quantitative PCR. Results: Foals inoculated with paralytic strains of EHV-1 developed both a greater magnitude and longer duration of PBMC-associated viraemia than foals inoculated with abortigenic strains of the virus. Conclusions: Both the higher magnitude and longer duration of cell-associated viraemia contribute to the risk for development of neurological signs in horses infected with paralytic strains of EHV-1. Potential relevance: Our results provide empirically derived, scientific data that contributes to a better understanding of the pathogenetic basis for the differing abilities of paralytic and abortigenic strains of EHV-1 to cause post infection central nervous system disease in the horse. The findings identify the importance of minimising the quantitative burden of viraemic leucocytes that follows exposure to the virus, by the use of effective therapeutic antiviral drugs and efficacious prophylactic vaccines that stimulate cytotoxic immune responses against EHV-1 infected cells. [source] A precise method for the impedance calculation of a power rail taking into account the skin effect and complex geometryEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 1 2000Y. J. Wang The method of coupled inductance based on subdivision of conductors is employed in this paper for calculating the impedance of a power rail (also known as the conductor rail or third rail) considering the skin effect and complex geometry. The proposed method also allows the current distribution over the rail cross-section to be determined. A numerical technique that is able to economize on the number of subconductors required to achieve a prescribed level of accuracy, is also proposed to reduce computation time and matrix dimensions. [source] WDX Studies on Ceramic Diffusion Barrier Layers of Metal Supported SOECsFUEL CELLS, Issue 6 2009D. Wiedenmann Abstract Solid oxide electrolyser cells (SOECs) have great potential for efficient and economical production of hydrogen fuel. Element diffusion between the Ni-cermet electrode and the metal substrate of metal supported cells (MSC) is a known problem in fuel cell and electrolysis technology. In order to hinder this unintentional mass transport, different ceramic diffusion barrier layers (DBLs) are included in recent cell design concepts. This paper is based on wavelength dispersive X-ray fluorescence investigations of different SOEC and focuses on Fe, Cr and Ni diffusion between the metal grains of the cathode and the metal substrate. Due to the low detection limits and therefore high analytical sensitivity, wavelength dispersive electron probe microanalysis (EPMA) provides a precise method to determine element distribution, absolute element concentration and changes between the reference material and aged cells on a microstructural level by element mappings and concentration profiles. The results of this work show considerable concentration gradients in the metal grains caused by mass exchange during cell operation. Diffusion can be inhibited significantly by integrating different ceramic DBLs of doped LaCrO3 -type or doped LaMnO3 -type perovskite, either by vacuum plasma spraying (VPS) or physical vapour deposition technique (PVD). [source] A standardized, comprehensive magnetic resonance imaging protocol for rapid and precise quantification of HIV-1-associated lipodystrophyHIV MEDICINE, Issue 7 2007M Bickel Objectives Although multiple methods have been proposed, there is no current gold standard for assessing HIV-1-associated lipodystrophy. Methods HIV-1-infected participants were randomly enrolled and surveyed about changes in the abdomen, thigh, cheek and neck areas. Magnetic resonance imaging (MRI) sequences of these sites were obtained. Participants were grouped according to survey results, and the MRI measurements were compared between groups. Results One hundred participants were included in the study, of whom 79% reported any body fat changes. Persons reporting increased abdominal girth had higher visceral ([mean±standard deviation] 142±75 vs. 59±48 cm2; P<0.0001) and total abdominal adipose tissue than those reporting no change (344±119 vs. 201±95 cm2; P<0.0001). The amount of localized fat was less for persons reporting sunken cheeks and reduced diameter of the legs compared with those who noted no changes (5.9±3.6 vs. 9.3±3.8 cm2; P<0.0001, and 35±28 vs. 112±56 cm2; P<0.0001). Participants reporting increased neck girth had a thicker fat layer in the dorsocervical region compared with those reporting no change (4.0±1.8 vs. 2.3±1.4 cm; P<0.0002). Conclusions MRI is a precise method for rapidly surveying body regions affected by HIV-1-associated lipodystrophy. Our proposed protocol provides a rapid, comprehensive survey of these areas, without the need to combine multiple modalities or to expose subjects to radiation. [source] Family history and inherited thrombophiliaJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 10 2006G. L. VAN SLUIS Summary.,Background: It is a common belief that patients with venous thrombosis and a positive family history for venous thromboembolism (VTE) have an increased likelihood of having an inherited thrombophilic defect. Methods: We analyzed the relation between family history, qualified with three different methods, and thrombophilic status in 314 patients with proven VTE. A positive family history (one or more first-degree relatives with VTE) and a strongly positive family history (two or more first-degree relatives with VTE). In 118 of the patients a third, more precise method was analyzed: the family history score, which compares the observed and the expected number of first-degree family members with VTE. Results: Patients with a positive or strongly positive family history had a slightly increased chance of having inherited thrombophilia compared to those without a positive family history. For positive family history this was 42% vs. negative 32%, likelihood ratio 1.3 (95% confidence interval; CI 0.9,2.1) and for strongly positive family history this was 46% vs. negative 34%, likelihood ratio 1.6 (95% CI 0.7,3.3). The family history score correlated with the chance of having inherited thrombophilia [OR 1.23 per score point (95% CI 1.01,1.48)]. However, even with this method the chance of having inherited thrombophilia is lower than 50% in 97% of the cases. Conclusions: Family history of VTE is not a precise tool in clinical practice to identify patients with inherited thrombophilia among patients with VTE. The family history score is more precise, but probably only useful for research purposes and not for daily practice. [source] Rigid-plastic hybrid element analyses of the plane strain upsettingNUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 6 2002Yong-Ming Guo Abstract A rigid-plastic hybrid element method (HEM) for simulation of metal forming is developed. This method is a mixed approach of the rigid-plastic domain-BEM and the rigid-plastic FEM based on the theory of compressible plasticity. Because the compatibilities of not only velocity but also velocity's derivative between the adjoining boundary elements and finite elements can be met, the velocities and the derivatives of the velocity can be calculated with the same precision for the rigid-plastic HEM. Then, it is considered that the rigid-plastic HEM is a more precise method in formulation than the conventional rigid-plastic FEMs for which the compatibilities of velocity's derivative cannot be met. The plane strain upsetting processes with two friction factors are analyzed by the rigid-plastic HEM in this article. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 726,737, 2002; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/num.10031. [source] Solid-phase extraction and reversed-phase high-performance liquid chromatography of the five major alkaloids in Narcissus confususPHYTOCHEMICAL ANALYSIS, Issue 6 2002Susana López Abstract A novel, fast and precise method, combining solid-phase extraction and reversed-phase high-performance liquid chromatography is described for the quantitative determination of five alkaloids (galanthamine, N -formylnorgalanthamine, haemanthamine, homolycorine and tazettine/pretazettine) from bulbs of wild Narcissus confusus, a high galanthamine-containing plant species growing in the Iberian Peninsula. Copyright © 2002 John Wiley & Sons, Ltd. [source] Direct quantification of 11-nor-,9 -tetrahydrocannabinol-9-carboxylic acid in urine by liquid chromatography/tandem mass spectrometry in relation to doping control analysisRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2010C. Chebbah An accurate and precise method for the quantification of 11-nor-,9 -tetrahydrocannabinol-9-carboxylic acid (THCA) in urine by liquid chromatography/tandem mass spectrometry (LC/MS/MS) for doping analysis purposes has been developed. The method involves the use of only 200,µL of urine and the use of D9 -THCA as internal standard. No extraction procedure is used. The urine samples are hydrolysed using sodium hydroxide and diluted with a mixture of methanol/glacial acetic acid (1:1). Chromatographic separation is achieved using a C8 column with gradient elution. All MS and MS/MS parameters were optimised in both positive and negative electrospray ionisation modes. For the identification and the quantification of THCA three product ions are monitored in both ionisation modes. The method is linear over the studied range (5,40,ng/mL), with satisfactory intra-and inter-assay precision, and the relative standard deviations (RSDs) are lower than 15%. Good accuracy is achieved with bias less than 10% at all levels tested. No significant matrix effects are observed. The selectivity and specificity are satisfactory, and no interferences are detected. The LC/MS/MS method was applied for the analysis of 48 real urine samples previously analysed with a routine gas chromatography/mass spectrometry (GC/MS) method. A good correlation between the two methods was obtained (r2,>,0.98) with a slope close to 1. Copyright © 2010 John Wiley & Sons, Ltd. [source] New isotope ratio mass spectrometric method of precise ,37Cl determinationsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2009Stanislaw Halas The most precise method of chlorine isotope analysis described to date is based on the isotope ratio mass spectrometry (IRMS) of chlorine quantitatively converted into chloromethane, CH3Cl. This gas can be produced from several chlorine-containing compounds and analyzed by IRMS. However, the mass spectrum of chloromethane is rather complicated and the ratio of the most abundant ions (mass-52/mass-50) differs from the 37Cl/35Cl isotope ratio. This difference becomes significant when the , exceeds 10,. Moreover, the electron ionization source yields approximately 80% of all the ionic species at the useful masses 50 and 52. To overcome these drawbacks, we have devised a negative ion mass spectrometer which retains all the best features of IRMS, including a dual-inlet system with changeover valve, dual collector assembly and CH3Cl gas as analyte. In the modified ion source we have replaced the ionization chamber with an electron beam by a metal tube with a hot metal filament inside it. Within this tube the 35Cl, and 37Cl, ions are produced with an efficiency dependent on the filament material and its temperature. No other ionic species were found in the mass spectrum except of traces at masses 26 and 28 at ppm levels, probably due to the formation of CN, and CO,. The minimal amount of Cl used in our method is of the order of 5,µmol (3,mg AgCl) and the precision is better than 0.005, (1,). Copyright © 2009 John Wiley & Sons, Ltd. [source] Rapid identification of differentiation markers from whole epithelial cells by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and statistical analysisRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2008Laure F. Marvin-Guy Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) was applied to identify markers for cellular differentiation. The differentiation of a human colon epithelial carcinoma T84 cell line was monitored over a period of 28 days by transepithelial electrical resistance (TER) measurements, alkaline phosphatase (AP) assay, and MALDI-TOF mass spectral fingerprints combined with statistical analysis. MALDI-MS generated specific mass spectral fingerprints characteristic of cell differentiation. Twenty-two ions were selected as diagnostic signals of fully differentiated T84 cells. Ten protein ion signals, detected by MALDI-MS and validated by statistical analysis, were proposed as T84 cell differentiation markers. Among these signals, ubiquitin was identified as a T84 cell differentiation marker by nanospray liquid chromatography/tandem mass spectrometry (nanoLC/MS/MS). Moreover, depending on the concentration of the cells seeded on the growth support, it was possible to predict the timing of the exponential phase and of cellular differentiation by MALDI-MS-derived marker ions. MALDI-TOFMS was compared to other methods for the determination of cellular differentiation: TER measurements are rapid but yield limited information as to the cellular differentiation state. AP assays are more specific for the differentiation state but take more time. By contrast, MALDI-MS has been found to be a fast, sensitive and precise method for cell differentiation assessment and provides the opportunity for multiplexing and high throughput. Moreover, the consumable costs per assay are very low. Copyright © 2008 John Wiley & Sons, Ltd. [source] Occlusion of the Middle Cerebral Artery: a New Method of Focal Cerebral Ischemia in RatsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005E. Cam The study in Wistar rats attempted to improve the occlusion technique of the middle cerebral artery (MCA) as a precise method for initiating stroke. In a first part it was necessary to study the exact anatomy of blood vessels of the brain in seven rats of 170-410 g body weight by corrosion cast. The lengths and diameters of defined locations of the blood vessels were measured. The temporary as well as the permanent methods were refined or replaced. The first one was completed in main training the physiological blood flow after temporary occlusion, while the permanent occlusion was performed by positioning a silicone cap in the MCA. A filament guide was introduced from the common carotid artery (CCA) via internal carotid artery (ICA) to guide the silicon cap at the branch of the MCA. Histological sections of the brain of rats showed 24 h after the permanent occlusion a reproducible infarct in the brain. This area corresponded very well with the supply of the MCA. The new occlusion method with a silicon cap was compared with the occlusion methods of CCA route and external carotid artery (ECA) route. The total infarct volume was significantly larger in the CCA route and ECA route groups than in the silicon cap group (means: CCA route 261 mm3; ECA route 191 mm3 vs. 128 mm3 silicon cap group; P < 0,05). It could be demonstrated that the new silicon cap occlusion technique imitates the pathological situation of a cerebral infarct in man. Moreover it is less invasive for the animals and more precise and reproducible regarding the infarcted area in comparison to the other occlusion methods. Based on anatomical measurements of the blood vessels the described silicon cap method can be recommended for rats of a body weight between 340,370 g. [source] | |||||||||||||