Search results for "Partition"
showing 10 items of 411 documents
Study of relationships between the structure of aroma compounds and their retention-release between vapour phase and dairy gels
2010
An integrated approach physicochemistry and structures activity relationships has been carried out to study the aroma compounds retention-release phenomenon in a fat free dairy gel added with pectin. This study aimed to identify the molecular properties that govern this phenomenon assuming that modifying the structure leads automatically to a change in the retention-release of aroma compounds. For this purpose, we have determined the partition coefficients of 28 aroma compounds in water, in pectin gels and in dairy gels supplemented or not supplemented with pectin, at equilibrium conditions using the PRV method (Phase Ratio Variation). Then, we have performed a structure-retention relations…
Biopartitioning micellar chromatoraphy to predict blood to lung, blood to liver, blood to fat and blood to skin partition coefficients of drugs
2009
[EN] Biopartitioning micellar chromatography (BMC), a mode of micellar liquid chromatography that uses micellar mobile phases of Brij35 in adequate experimental conditions, has demonstrated to be useful in mimicking the drug partitioning process into biological systems. In this paper, the usefulness of BMC for predicting the partition coefficients from blood to lung, blood to liver. blood to fat and blood to skin is demonstrated. PLS2 and multiple linear regression (MLR) models based on BMC retention data are proposed and compared with other ones reported in bibliography. The proposed models present better or similar descriptive and predictive capability. (C) 2008 Elsevier B.V. All rights r…
Determination of the hydrophobicity of organic compounds measured as logPo/w through a new chromatographic method
2009
A new chromatographic method to determine the octanol-water partition coefficient (logP(o/w)) of organic substances is proposed in this paper. This method is based on a previously reported model that relates the retention factor in reversed-phase liquid chromatography with solute (p), mobile phase (P(m)(N)) and stationary phase (P(s)(N)) polarity parameters: logk=(logk)(0)+p(P(m)(N)-P(s)(N)). P(m)(N) values are calculated through expressions that depend only on the organic solvent fraction in the mobile phase. (logk)(0) and P(s)(N) parameters are characteristic of the chromatographic system and are determined from the retention of a selected set of 12 compounds. Then, the p value of a solut…
QSPR prediction of chromatographic retention times of pesticides: Partition and fractal indices
2014
The high-performance liquid-chromatographic retentions of red-wine pesticide residues are modeled by structure-property relationships. The effect of different types of features is analyzed: geometric, lipophilic, etc. The properties are fractal dimensions, partition coefficient, etc., in linear and nonlinear correlation models. Biological plastic evolution is an evolutionary perspective conjugating the effect of acquired characters and relations that emerge among the principles of evolutionary indeterminacy, morphological determination and natural selection. It is applied to design the co-ordination index that is used to characterize pesticide retentions. The parameters used to calculate th…
Multi-target QSPR assemble of a Complex Network for the distribution of chemicals to biphasic systems and biological tissues
2008
Abstract Chemometrics, that based prediction on the probability of chemical distribution to different systems, is highly important for physicochemical, environmental, and life sciences. However, the amount of information is huge and difficult to analyze. A multi-system partition Complex Network (MSP-CN) may be very useful in this sense. We define MSP-CNs as large graphs composed by nodes (chemicals) interconnected by arcs if a pair of chemicals have similar partition in a given system. Experimental quantification of partition in many systems is expensive, so we can use a Quantitative Structure–Partition Relationship (QSPR) model. Unfortunately, with classic QSPR we need to use one model for…
Unified Markov thermodynamics based on stochastic forms to classify drugs considering molecular structure, partition system, and biological species:
2005
Abstract To date, molecular descriptors do not commonly account for important information beyond chemical structure. The present work, attempts to extend, in this sense, the stochastic molecular descriptors (Gonzalez-Diaz, H. et al., J. Mol. Mod. 2002, 8, 237), incorporating information about the specific biphasic partition system, the biological species, and chemical structure inside the molecular descriptors. Consequently, MARCH-INSIDE molecular descriptors may be identified with time-dependent thermodynamic parameters (entropy and mean free energy) of partition process. A classification function was developed to classify data of 423 drugs and up to 14 different partition systems at the s…
Modeling the chiral resolution ability of highly sulfated β-cyclodextrin for basic compounds in electrokinetic chromatography
2013
Abstract Despite the fact that extensive research in the field of enantioseparations by capillary electrophoresis has been carried out, it is difficult to predict whether a concrete chiral selector would be useful for the separation of a racemic compound. Hence, several experimental effort is necessary to test the abilities of individual chiral selectors, usually by trial and error procedures. Thus, the enantioseparation of a new racemate becomes a time- and money-consuming task. In this work, the ability of highly sulfated β-cyclodextrin (HS-β-CD) as chiral selector in electrokinetic chromatography (EKC) is modeled for the first time, using exclusively directly-available structural data of…
Ectopic expression of the AtCDF1 transcription factor in potato enhances tuber starch and amino acid contents and yield under open field conditions
2023
16 Pág.
Seasonal patterns of C-13 partitioning between shoots and nodulated roots of N2 or nitrate-fed Pisum sativum L
2003
International audience
Low-pressure synthesis and Bridgman growth of Hg1−xMnxTe
1999
To reduce Hg high pressure related to the high-temperature synthesis reaction between the components in elemental form, Hg 1-x Mn x Te bulk crystals were produced by a two-step procedure including (I) the alloy synthesis using HgTe crystals grown by the cold travelling heater method and elemental Mn and Te to complete the desired composition, followed by (II) the Bridgman growth. The growth was carried out at temperature in the range of 700-850°C and rate of 1 mm/h. The Hg 1-x Mn x Te crystals have been characterised by X-ray diffractometry, energy dispersive X-ray analysis, Fourier transformed infrared spectroscopy and Hall effect techniques. Although the distribution coefficient of Mn was…