Search results for "Concentration."
showing 10 items of 1849 documents
Effect of buffer nature and concentration on the chromatographic performance of basic compounds in the absence and presence of 1-hexyl-3-methylimidaz…
2019
Abstract In reversed-phase liquid chromatography, the performance for basic compounds is affected by the interaction of the protonated (cationic) species with the anionic free silanols on the alkyl-bonded stationary phases. Using aqueous-organic mobile phases in the absence of additives, the retention may be too high, and the peaks be broad and asymmetric. The performance is improved by addition to the mobile phase of ionic liquids, from which 1-hexyl-3-methylimidazolium chloride ([C6MIm][Cl]) has especially good characteristics. A recent report has also revealed that the use of the phosphate system as buffer, at varying concentration and pH, may have a significant role in the chromatograph…
Trauma and testimony: Jorge Semprún’s experience
2018
En el siglo XX tuvieron lugar múltiples acontecimientos históricos de naturaleza traumática que dejaron una huella profunda en la historia de la humanidad. Ante vivencias de esta índole, el ser humano busca expresar su herida a través de las múltiples formas culturales, siendo una de ellas la literatura. Este artículo pretende, en primer lugar, definir el concepto de trauma, su integración en el campo de la psiquiatría y las posibilidades de superación a partir de su puesta en discurso; en segundo lugar, proponer los rasgos que caracterizan al testimonio como el género literario idóneo para dar cuenta de dichas vivencias; finalmente, analizar el caso del escritor Jorge Semprún y la verbaliz…
La experiencia del Mal Radical en la obra de Jorge Semprún = The experience of Radical Evil in the works of Jorge Semprún
2017
<p align="JUSTIFY"><span style="font-family: 'Book Antiqua', serif;"><span style="font-size: small;">Este artículo pretende realizar un análisis de las novelas sobre los campos de concentración del escritor Jorge Semprún. Partiendo de la dicotomía escribir o vivir como un estado psicológico del autor tras su liberación, se reflexionará sobre las posibilidades de la literatura y del artificio como transmisores capaces de hacer entender la experiencia concentracionaria. Finalmente, se analizará el concepto filosófico del Mal Radical, señalado por Semprún como un elemento clave para entender dicha experiencia.</span></span></p><p align="JUSTIFY"><sp…
The effectiveness of various types of ventilation on air quality in multi-family buildings
2017
Przepisy prawne oraz normy obligują do kontroli systemów wentylacji budynków jedynie pod względem prędkości strumienia powietrza, co niestety nie zawsze gwarantuje zalecaną ze względów zdrowotnych jakość powietrza. W pracy podjęto badania skuteczności różnych typów wentylacji wielorodzinnych budynków mieszkalnych, ze szczególnym uwzględnieniem wentylacji naturalnej, stanowiącej najczęściej spotykane rozwiązanie w budynkach mieszkalnych w Polsce. Badano wpływ skuteczności wentylacji na podstawowe parametry charakteryzujące jakość powietrza, tj. stężenie ditlenku węgla, wilgotność względną oraz temperaturą. Badano również możliwość regulacji pracy systemu wentylacji budynków wielorodzinnych w…
Badania skuteczności wentylacji pomieszczeń sypialni w wielorodzinnych budynkach mieszkalnych
2017
Skuteczność systemów wentylacji budynków mieszkalnych kontrolowana jest jedynie poprzez pomiar prędkości strumienia powietrza w kanale wentylacyjnym, co nie gwarantuje odpowiedniej kontroli jakości powietrza. W pracy przedstawiono wyniki badań skuteczności wentylacji naturalnej wielorodzinnych budynków mieszkalnych, stanowiącej najczęściej spotykane rozwiązanie w budynkach mieszkalnych w Polsce. Szczególną uwagę zwrócono na wentylację pomieszczenia sypialni, jako pomieszczenia, w którym spędza się około 1/3 czasu w ciągu dnia. Badano wpływ skuteczności systemu wentylacji na podstawowe parametry charakteryzujące jakość powietrza, tj. stężenie ditlenku węgla, wilgotność względną oraz temperat…
SCD5-induced oleic acid production reduces melanoma malignancy by intracellular retention of SPARC and cathepsin B
2014
A proper balance between saturated and unsaturated fatty acids (FAs) is required for maintaining cell homeostasis. The increased demand of FAs to assemble the plasma membranes of continuously dividing cancer cells might unbalance this ratio and critically affect tumour outgrowth. We unveiled the role of the stearoyl-CoA desaturase SCD5 in converting saturated FAs into mono-unsaturated FAs during melanoma progression. SCD5 is down-regulated in advanced melanoma and its restored expression significantly reduced melanoma malignancy, both in vitro and in vivo, through a mechanism governing the secretion of extracellular matrix proteins, such as secreted protein acidic and rich in cysteine (SPAR…
Cross-modal interactions between taste and smell: Odour-induced saltiness enhancement depends on salt level
2011
International audience; In recent years, health concerns related to salt have led to extensive research on low-salt foods. One major remaining issue is to reduce sodium content while still providing the salty fix, to maintain food appreciation, acceptance and choice. Using well-selected odours has been proposed to compensate for sodium chloride reduction in food, due to the cross-modal interactions between odour and taste. However, interactions between taste and odour, with regards to saltiness, remain poorly investigated. Moreover, although a few studies have assessed the influences of odour and sweet supra-threshold intensity on cross-modal interactions, none focused directly on how they …
Observations on the use of a sulfuric acid medium for As(V) to As(III) reduction in lodimetric titrations: Application to the determination of total …
1991
Abstract The use of a sulfuric rather than a hydrochloric acid medium for the reduction of As(V) to As(III) by iodide is proposed. Optimum conditions of acid concentration, amount of sodium hydroxide, and time and temperature are established to achieve quantitative reduction. The optimized reduction procedure was applied to the iodimetric determination of total arsenic and compared to a procedure that employs a hydrochloric acid medium. A systematic error of 0.04% was found for the method with a sulfuric acid medium opposed to 0.05% for the method with a hydrochloric acid medium in the reduction step. The proposed modified iodimetric method has been successfully used with some organic sampl…
Small angle scattering study of poly(methylmethacrylate)-blockpoly(ethylene oxide) block co-polymer in aqueous solution
2005
A combined Small Angle X ray (SAXS) and Neutron (SANS) Scattering study of aqueous solutions of a symmetric block copolymer consisting of poly(methyl methacrylate) (PMMA) and poly(ethylene oxide) (PEO) moieties is presented. The polymer forms slightly polydisperse spherical micelles in a wide range of concentration (0.03 – 6.7 w/V) and temperature (20°C ≤ T ≤ 65°C). A good description of the SANS data is obtained using a polydisperse core-shell model with a structure factor for a modified hard sphere potential. By increasing the concentration at constant T we observed a decrease of the aggregation number and an increase of solvation of PEO groups in the shell, opposite to what happens by in…
Ability of Kocuria varians LTH 1540 To Degrade Putrescine: Identification and Characterization of a Novel Amine Oxidase.
2015
This work describes the identification and characterization of an amine oxidase from Kocuria varians LTH 1540 (syn. Micrococcus varians) primarily acting on putrescine. Data from MALDI-TOF MS/MS and the identification of Δ(1)-pyrroline as degradation product from putrescine indicate that the enzyme is a flavin-dependent putrescine oxidase (PuO). Properties of partially purified enzyme have been determined. The enzyme oxidizes diamines, putrescine and cadaverine, and, to a lesser extent, polyamines, such as spermidine, but not monoamines. The kinetic constants (Km and Vmax) for the two major substrates were 94 ± 10 μM and 2.3 ± 0.1 μmol/min·mg for putrescine and 75 ± 5 μM and 0.15 ± 0.02 μmo…