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partition coefficient

Yanyan Wang, Lihong Zhang, Dingding Wang, Xiuyun Guo, Shihua Wu
Counter-current chromatography (CCC) is a solid support-free liquid-liquid partition chromatography and has wide applications. However, CCC separation is still a challenging process and the selection of appropriate solvent system for separation of target compound(s) is still relatively time-consuming. In this work, we introduced a room temperature ionic liquids-based salting-in strategy for the rapid selection of suitable solvent systems for CCC separation. In the randomly selected solvent systems, such as ethyl acetate-water, n-butanol-water, n-pentanol-water, n-hexanol-water, and n-octanol-water, several ionic liquids such as [AMIM]Cl, [MAMIM]Cl, and [BMIM]Cl can increase the solubility of the solutes in the lower phase, which made a dose-dependent decreasing of partition coefficient of solute in the two-phase solvent system...
November 30, 2016: Journal of Chromatography. A
Mengjie Qu, Huidong Li, Na Li, Guanglong Liu, Jianwei Zhao, Yumei Hua, Duanwei Zhu
We investigated sediments with high atrazine accumulation capability from 6 eutrophic lakes in Hubei Province of central China. Almost all lakes have atrazine in their sediments because of human activities. Honghu Lake and Liangzihu Lake were found to have higher levels of atrazine in sediment: 0.171 and 0.114 mg kg(-1), respectively. The results showed that lake sediments could adsorb atrazine six times faster than soils. The equilibrium partition coefficient of atrazine desorption (KPd) is much larger than the adsorption equilibrium partition coefficient (KPa) of atrazine, indicating that the residue of atrazine in water is easily immobilized by the sediments...
December 5, 2016: Chemosphere
Christian F Pantoja, Jose A Bolaños, Andrés Bernal, Julien Wist
We introduce a new approach for resolving the NMR spectra of mixtures that relies on the mutual diffusion of dissolved species when a concentration gradient is established within the NMR tube. This is achieved by cooling down a biphasic mixture of triethylamine and deuterated water below its mixing temperature, where a single phase is expected. Until equilibrium is reached, a gradient of concentration, from "pure" triethylamine to "pure" water, establishes within the tube. The amount of time required to reach this equilibrium is controlled by the mutual diffusion coefficient of both species...
December 8, 2016: Magnetic Resonance in Chemistry: MRC
Thomas Buchecker, Sebastian Krickl, Robert Winkler, Isabelle Grillo, Pierre Bauduin, Didier Touraud, Arno Pfitzner, Werner Kunz
In the present contribution, the pre-structuring of binary mixtures of hydrotropes and H2O is linked to the solubilisation of poorly water miscible compounds. We have chosen a series of short-chain alcohols as hydrotropes and benzyl alcohol, limonene and a hydrophobic azo-dye (Disperse Red 13) as organic compounds to be dissolved. A very weak pre-structuring is found for ethanol/H2O and 2-propanol/H2O mixtures. Pre-structuring is most developed for binary 1-propanol/H2O and tert-butanol/H2O mixtures and supports the bicontinuity model of alcohol-rich and water-rich domains as already postulated by Anisimov et al...
December 8, 2016: Physical Chemistry Chemical Physics: PCCP
Nguyen Tien Huy, Pham Lan Chi, Jun Nagai, Tran Ngoc Dang, Evaristus Chibunna Mbanefo, Ali Mahmoud Ahmed, Nguyen Phuoc Long, Le Thi Bich Thoa, Le Phi Hung, Titouna Afaf, Kaeko Kamei, Hiroshi Ueda, Kenji Hirayama
It is essential to continue the search for novel antimalarial drugs due to current spread of resistance against artemisinin by Plasmodium falciparum parasites. In this study, we developed in silico models to predict hemozoin inhibitors as a potential first-step screening for novel antimalarials. The in vitro colorimetric high throughput screening assay of hemozoin formation was used to identify hemozoin inhibitors from 9600 structurally diverse compounds. Physicochemical properties of positive hits and randomly selected compounds were extracted from ChemSpider database; they were used for developing prediction models to predict hemozoin inhibitors using two different approaches, i...
December 5, 2016: Antimicrobial Agents and Chemotherapy
Giacomo Russo, Lucia Grumetto, Francesco Barbato, Giulio Vistoli, Alessandro Pedretti
The present study proposes a method for an in silico calculation of phospholipophilicity. Phospholipophilicity is intended as the measure of analyte affinity for phospholipids; it is currently assessed by HPLC measures of analyte retention on phosphatidylcholine-like stationary phases (IAM - Immobilized Artificial Membrane) resulting in log kW(IAM) values. Due to the amphipathic and electrically charged nature of phospholipids, retention on these stationary phases results from complex mechanisms, being affected not only by lipophilicity (as measured by n-octanol/aqueous phase partition coefficients, log P) but also by the occurrence of polar and/or electrostatic intermolecular interaction forces...
December 2, 2016: European Journal of Pharmaceutical Sciences
L Berthod, D C Whitley, G Roberts, A Sharpe, R Greenwood, G A Mills
Understanding the sorption of pharmaceuticals to sewage sludge during waste water treatment processes is important for understanding their environmental fate and in risk assessments. The degree of sorption is defined by the sludge/water partition coefficient (Kd). Experimental Kd values (n=297) for active pharmaceutical ingredients (n=148) in primary and activated sludge were collected from literature. The compounds were classified by their charge at pH7.4 (44 uncharged, 60 positively and 28 negatively charged, and 16 zwitterions)...
December 2, 2016: Science of the Total Environment
Anukul Boonloed, Genevieve L Weber, Kelly M Ramzy, Veronica R Dias, Vincent T Remcho
A centrifugal partition chromatography (CPC) method was developed for the preparative-scale isolation and purification of xylindein from the wood-staining fungi, Chlorociboria aeruginosa. Xylindein, a blue-green pigment naturally secreted from the hyphae and fruiting bodies of the fungus, has great value in the decorative wood industry and textile coloration. Xylindein has great potential for use as a fluorescent labeling agent as well as in organic semiconductor applications. However, a primary limitation of xylindein is its poor solubility in most common HPLC solvents...
November 18, 2016: Journal of Chromatography. A
Katarína Garajová, Anna Balogová, Eva Dušeková, Dagmar Sedláková, Erik Sedlák, Rastislav Varhač
Enzymatic activity and stability of lysozyme in the presence of salts have been studied by fluorescence spectroscopy and differential scanning calorimetry, respectively. The effect of sodium salts of sulfate, acetate, chloride, bromide, thiocyanate, and perchlorate on lysozyme properties depends on anion concentration as well as on position of anion in the Hofmeister series. Kosmotropic anions (sulfate and acetate) increase stability and activate the enzyme while chaotropic anions (bromide, thiocyanate and perchlorate) including chloride decrease stability and inhibits the enzyme activity...
November 30, 2016: Biochimica et Biophysica Acta
Okan Bulut, Mark L Davison, Michael C Rodriguez
Subscores are of increasing interest in educational and psychological testing due to their diagnostic function for evaluating examinees' strengths and weaknesses within particular domains of knowledge. Previous studies about the utility of subscores have mostly focused on the overall reliability of individual subscores and ignored the fact that subscores should be distinct and have added value over the total score. This study introduces a profile reliability approach that partitions the overall subscore reliability into within-person and between-person subscore reliability...
November 29, 2016: Multivariate Behavioral Research
Feike J Leij, Scott A Bradford, Antonella Sciortino
Elucidating and quantifying the transport of industrial nanoparticles (e.g. silver, carbon nanotubes, and graphene oxide) and other colloid-size particles such as viruses and bacteria is important to safeguard and manage the quality of the subsurface environment. Analytic solutions were derived for aqueous and solid phase colloid concentrations in a porous medium where colloids were subject to advective transport and reversible time and/or depth-dependent retention. Time-dependent blocking and ripening retention were described using a Langmuir-type equation with a rate coefficient that respectively decreased and increased linearly with the retained concentration...
December 2016: Journal of Contaminant Hydrology
Christiaan Jardínez, Alberto Vela, Julián Cruz-Borbolla, Rodrigo J Alvarez-Mendez, José G Alvarado-Rodríguez
The relationship between the chemical structure and biological activity (log IC50) of 40 derivatives of 1,4-dihydropyridines (DHPs) was studied using density functional theory (DFT) and multiple linear regression analysis methods. With the aim of improving the quantitative structure-activity relationship (QSAR) model, the reduced density gradient s( r) of the optimized equilibrium geometries was used as a descriptor to include weak non-covalent interactions. The QSAR model highlights the correlation between the log IC50 with highest molecular orbital energy (E HOMO), molecular volume (V), partition coefficient (log P), non-covalent interactions NCI(H4-G) and the dual descriptor [Δf(r)]...
December 2016: Journal of Molecular Modeling
Gerald Matisoff
In lakes with a large surface area to watershed ratio (137)Cs delivery is primarily by direct atmospheric fallout to the lake surface, where its activity in the sediments has been used to estimate the exposure to organisms and sediment mass deposition rates. Comparison of (137)Cs in the historical atmospheric fallout record with (137)Cs activity profiles in sediment cores reveals that although the general features of a maxima in the fallout deposition can be matched to activity peaks in the core, the general shape of the (137)Cs profile is not an exact replica of the fallout history...
November 23, 2016: Journal of Environmental Radioactivity
Peter C Austin, Philippe Wagner, Juan Merlo
Multilevel data occurs frequently in many research areas like health services research and epidemiology. A suitable way to analyze such data is through the use of multilevel regression models (MLRM). MLRM incorporate cluster-specific random effects which allow one to partition the total individual variance into between-cluster variation and between-individual variation. Statistically, MLRM account for the dependency of the data within clusters and provide correct estimates of uncertainty around regression coefficients...
November 25, 2016: Statistics in Medicine
Xiangrong Zhang, Yi Zhang, Shuang Guo, Feifei Bai, Tong Wu, Yuqing Zhao
The aim of the study was to improve the oral absorption of the compound 25-OCH3-PPD with poor hydrophilicity and lipophilicity. 25-OCH3-PPD-phospholipid complex was prepared by solvent evaporation, then characterized by differential scanning calorimetry, scanning electron microscopy, and infrared absorption spectroscopy. The aqueous solubility and oil-water partition coefficient were compared with the free compound. A nanoemulsion loaded with 25-OCH3-PPD-phospholipid complex was developed by dissolving the complex in water in the presence of hydrophilic surfactant under sonication...
2016: Drug Design, Development and Therapy
Dipta B Ghosh, Bijaya B Karki
The low/ultralow-velocity zones in the Earth's mantle can be explained by the presence of partial melting, critically depending on density contrast between the melt and surrounding solid mantle. Here, first-principles molecular dynamics simulations of (Mg, Fe) O ferropericlase in the solid and liquid states show that their densities increasingly approach each other as pressure increases. The isochemical density difference between them diminishes from 0.78 (±0.7) g/cm(3) at zero pressure (3000 K) to 0.16 (±0...
November 22, 2016: Scientific Reports
Scott A Miller, Carol A Aschenbrenner, Justin R Traunero, Loren A Bauman, Samuel S Lobell, Jeffrey S Kelly, John E Reynolds
STUDY OBJECTIVE: Volatile anesthetic agents comprise a substantial portion of every hospital's pharmacy budget. Challenged with an initiative to lower anesthetic drug expenditures, we developed an education-based intervention focused on reducing volatile anesthetic costs while preserving access to all available volatile anesthetics. When postintervention evaluation demonstrated a dramatic year-over-year reduction in volatile agent acquisition costs, we undertook a retrospective analysis of volatile anesthetic purchasing data using time series analysis to determine the impact of our educational initiative...
December 2016: Journal of Clinical Anesthesia
F-D Kopinke, A Georgi, G Imfeld, H-H Richnow
Isotope fractionation between benzene-D0 and benzene-D6 caused by multi-step partitioning of the benzenes between water and two organic solvents, n-octane and 1-octanol, as well as between water and the gas phase, was measured. The obtained fractionation factors αH = KH/KD are αH = 1.080 ± 0.015 and αH = 1.074 ± 0.015 for extraction into n-octane and 1-octanol, respectively, and αH = 1.049 ± 0.010 for evaporation from aqueous solution. The comparison of solvent- and gas-phase partitioning reveals that about 2/3 of the driving force of fractionation is due to different interactions in the aqueous phase, whereas 1/3 is due to different interactions in the organic phase...
November 18, 2016: Chemosphere
Malay Patra, Manoj Mandal, Abhijit Chakrabarti, Chaitali Mukhopadhyay
Structural transitions involving shape changes play an important role in cellular physiology and enhance the bioavailability of the natural food like curcumin in surfactant aggregates. In this work, we have studied the localization, dynamics and stability of curcumin in various miceller assemblies using a combination of absorbance and fluorescence spectroscopic approaches. The measurements of absorption and fluorescence spectra of curcumin revealed that the nature of interactions of ionic and nonionic surfactants and the glycosphingolipid, GM1 with curcumin is significantly different with surfactant concentrations...
November 19, 2016: Glycoconjugate Journal
Shi-Yu Zong, Yi-Qiong Pu, Ben-Liang Xu, Tong Zhang, Bing Wang
Paeonol, an active component from Paeonia suffruticosa Andr., has a variety of biological activities, such as vascular endothelial cell protection, anti-oxidation, and anti-inflammation. The aim of this study was to investigate the basic physicochemical properties of paeonol, including solubility, oil-water partition coefficient, and permeability. Then evaluated the anti-inflammatory effects of paeonol were evaluated on 2,4,6-trinitrobenzenesulfonic acid-induced ulcerative colitis in rats. The rats were divided randomly into 6 groups, namely, normal, model, paeonol-treated (100, 200, and 400mg/kg), and positive...
November 15, 2016: International Immunopharmacology
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