Search results for "PLATE"

Gel permeation Chromatography in coiled columns

1973

Whereas in gas chromatography the use of coiled columns is the usual procedure, in liquid chromatography the use of straight columns is favoured. Bent columns give an additional contribution to peak spreading which is of greater importance in liquid chromatography than in gas chromatography owing to smaller diffusion coefficients. The low linear velocities of the mobile phase used in gel permeation chromatography enable conditions to be found where the additional contribution of bending to peak spreading is small. In the separation of oligomers, columns of 2-mm tube diameter and 20-cm coil diameter were used. With total lengths of 10 and 20 m, theoretical plate counts of ca. 70,000 and 150,…

A theoretical plate model accounting for slow kinetics in chromatographic elution.

2011

The chromatographic elution has been studied from different perspectives. However, in spite of the simplicity and evident deficiencies of the plate model proposed by Martin and Synge, it has served as a basis for the characterization of columns up-to-date. This approach envisions the chromatographic column as an arbitrary number of theoretical plates, each of them consisting of identical repeating portions of mobile phase and stationary phase. Solutes partition between both phases, reaching the equilibrium. Mobile phase transference between the theoretical plates is assumed to be infinitesimally stepwise (or continuous), giving rise to the mixing of the solutions in adjacent plates. This yi…

Extraktionschromatographische trennung der freien uroporphyrinisomere i und iii und deren simultane quantitative bestimmung

1968

Abstract Separation and simultaneous quantitative determination of the free uroporphyrin isomers I and III by means of extraction chromatography Separation and quantitative determination of the uroporphyrin isomers I and III in the acid from can be performed simultaneously in the partition system tri-n-butylphosphate/I N hydrochloric acid using columns with a large number of theoretical plates (N) = 300-450). The eluent is passed through a flow cuvette and the transmission is recorded continuously. The transmission peaks of the isomers are digitized and transformed into extinction values. By integrating the extinction peaks, the amount of the uroporphyrins can be evaluated from the correspo…

An Intercalibration Study of the Use of 4-Methylumbelliferyl-β-D-Glucuronide for the Specific Enumeration of Escherichia coli in Seawater and Marine …

1991

Summary A fluorogenic assay for the specific detection of Escherichia coli on the basis of its β-glucuronidase activity (MUG method) was applied to seawater and marine sediments with different contamination levels. The study was carried out in three Mediterranean areas (Malaga-Spain, Nice-France and Palermo-Sicily), using strictly standardized methods (membrane filtration), media (mFC and Chapman-TTC agars) and reagents, to evaluate statistically its sensitivity and specificity according to the origin and contamination of samples, the workers performing the tests and the selected culture media. The results obtained indicate that the MUG method is highly specific (94.5%) and sensitive (90.8%…

Oral Glycoprotein IIb/IIa Antagonists for Unstable Angina — Is There Still a Chance for the Oral Substances?

2001

The intravenous glycoprotein IIb/IIIa antagonists abciximab, tirofiban and eptifibatide are well accepted for the therapy of patients with unstable angina and/or as concomitant medication during coronary interventions. Despite the fact that these drugs are not used in all patients presenting with unstable angina during coronary interventions, the scientific evidence is overwhelming including the substantial reduction in mortality 3 years after utilisation of abciximab for coronary interventions in patients with unstable angina. In addition to these two indications, intravenous glycoprotein IIb/IIIa antagonists are currently being investigated for use in patients undergoing carotid artery in…

Sulfinpyrazone and platelet function in hypertensive patients

1984

Phenotypic and genotypic evaluation of slime production by conventional and molecular microbiological techniques.

2009

Twenty-nine staphylococcal isolates from different clinical samples were tested for slime production: phenotypic characterization was carried out using Christensen test (tube test) and Congo red agar plate test (CRA plate test), while the presence and expression of icaA and icaD genes were evaluated by real-time PCR. In 79.3% of studied strains there was a concordance between slime production and presence of icaA and icaD genes, and between lack of slime production and absence of both or only one of the tested genes. In four of five strains where positive phenotype was not associated with the presence of ica genes, gene co-expression (evaluated by mRNA determination) was lacking, while in o…

Cellular Mechanisms of Subplate-Driven and Cholinergic Input-Dependent Network Activity in the Neonatal Rat Somatosensory Cortex

2008

Early coordinated network activity promotes the development of cortical structures. Although these early activity patterns have been recently characterized with respect to their developmental, spatial and dynamic properties, the cellular mechanisms by which specific neuronal populations trigger coordinated activity in the neonatal cerebral cortex are still poorly understood. Here we characterize the cellular and molecular processes leading to generation of network activity during early postnatal development. We show that the somatosensory cortex of newborn rats expresses cholinergic-driven calcium transients which are synchronized within the deeply located subplate. Correspondingly, endogen…

A computational aeroelastic framework based on high-order structural models and high-fidelity aerodynamics

2023

A computational framework for high-fidelity static aeroelastic analysis is presented. Aeroelastic analysis traditionally employs a beam stick representation for the structure and potential, inviscid and irrotational flow assumptions for the aerodynamics. The unique contribution of this work is the introduction of a high-order structural formulation coupled with a high-fidelity method for the aerodynamics. In more details, the Carrera Unified Formulation coupled with the Finite Element Method is implemented to model geometrically complex composite, laminated structures as equivalent bi-dimensional plates. The open-source software SU2 is then used for the solution of the aerodynamic fields. T…

Are there any differences in various polyaxial locking systems? A mechanical study of different locking screws in multidirectional angular stable dis…

2012

Numerous angular stable plates for the distal radius exist, and technically based comparisons of the polyaxial locking interfaces are lacking. The aim of this mechanical study was to investigate three different locking interfaces of angular stable volar plates by cantilever bending: VA-LCP Two-Column Distal Radius Plates 2.4 mm (Synthes® GmbH, Oberdorf, Switzerland), IXOS® P4 (Martin, Tuttlingen, Germany) and VariAX™ (Stryker®, Duisburg, Germany). We assessed the strength of 0°, 5°, 10° and 15° screw locking angles and tested the bending strength from 10° to 5° angles by cyclic loading until breakage. The final setup repeated the above assessments by inclusion of four locking screws. The si…