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Phase separation

Heba Elmotasem, Hala K Farag, Abeer A A Salama
The objective of this study was to innovate an effective oral sustained release hepatoprotective formula for - the water soluble drug - caffeine. Caffeine is rapidly absorbed and eliminated which dictates frequent administration to achieve adequate therapeutic effect. A w/o Pickering emulsion incorporating caffeine in the internal phase was primed. It contained wheat germ oil and was stabilized by synthesized magnesium oxide nanoparticles (MgO NPs). Components selection was based on their antioxidant, hepatoprotective and anticarcinogenic effects...
May 16, 2018: International Journal of Pharmaceutics
Dieter Muri, Martin R Edelmann
This practitioner protocol describes the use and application of different types of solid phase extractions and metal scavengers for small scale reactions, particularly in the context of purifying tritiated molecules from heavily contaminated reaction mixtures. Polymer-bound strong cation exchangers are especially suitable for separating basic compounds from neutral or acidic molecules and have been widely applied in the work-up of Iridium-based hydrogen isotope exchange reactions. Polymer-bound strong anion exchangers can help to separate acidic compounds from their neutral or basic counterparts or to easily convert a TFA or formate salt to its free base after HPLC purification...
May 19, 2018: Journal of Labelled Compounds & Radiopharmaceuticals
Yuantao Zhou, Shurui Cao, Cunxian Xi, Jiuyan Chen, Lei Zhang, Xianliang Li, Guomin Wang, Zhiqiong Chen
A magnetic solid-phase extraction adsorbent that consisted of citrus peel-derived nanoporous carbon and silica-coated Fe3 O4 microspheres (C/SiO2 @Fe3 O4 ) was successfully fabricated by co-precipitation. As a modifier for magnetic microspheres, citrus peel-derived nanoporous carbon was not only economical and renewable for its raw material, but exerted enormous nanosized pore structure, which could directly influence the type of adsorbed analytes. The C/SiO2 @Fe3 O4 also possessed the advantages of Fe3 O4 microspheres like superparamagnetism, that could be easily separated magnetically after adsorption...
May 18, 2018: Journal of Separation Science
Matthew W Wittstein, Joseph M Starobin, Randy J Schmitz, Sandra J Shulz, Francis Jay Haran, Christopher K Rhea
BACKGROUND: Aging and pathology result in changes in the dynamics of several physiological subsystems. Often, these changes are concurrent, altering the dynamics between subsystems. Cardiac and gait rhythms are one example in which patterns change during physical activity. AIMS: The purpose of this research is to simultaneously monitor changes in cardiac and gait rhythms when participants complete various treadmill walking tasks-normal speed, fast speed, and while synchronizing steps with a blinking metronome...
May 17, 2018: Aging Clinical and Experimental Research
Xiao-Fang Huang, Song-Zhao Zhang, Ya-Yu You, Na Zhang, Hong Lu, Alan Daugherty, Xiao-Jie Xie
Abdominal aortic aneurysms (AAAs) are a chronic vascular disease characterized by pathological luminal dilation. Aortic rupture is the fatal consequence of AAAs. Ginkgo biloba extracts (GBEs), a natural herb extract widely used as food supplements, drugs, and cosmetics, has been reported to suppress development of calcium chloride-induced AAAs in mice. Calcium chloride-induced AAAs do not rupture, while angiotensin II (AngII)-induced AAAs in mice have high rate of aortic rupture, implicating potentially different mechanisms from calcium chloride-induced AAAs...
May 18, 2018: Acta Pharmacologica Sinica
Radosław Ł Gwarda, Tadeusz H Dzido
In our previous papers we have investigated the influence of the mobile phase composition on mechanism of retention, selectivity and efficiency of peptide separation in various high-performance thin-layer chromatography (HPTLC) systems with commercially available silica-based adsorbents. We have also investigated the influence of pH of the mobile phase buffer on migration and separation of peptides in pressurized planar electrochromatography (PPEC). Here we investigate the influence of concentration of ion-pairing additive, and concentration and type of organic modifier of the mobile phase on migration of peptides in PPEC system with octadecyl silica-based adsorbent, and with the same set of the solutes as before...
May 15, 2018: Journal of Chromatography. A
Wolfgang Vautz, Joachim Franzke, Stefano Zampolli, Ivan Elmi, Sascha Liedtke
In this tutorial, we want to demonstrate the significant potential of ion mobility spectrometry (IMS), an analytical technique for identification and quantification of gas-phase compounds, in particular combined to other useful analytical tools. Coupled to gas-chromatographic pre-separation (GC-IMS), selectivity can be improved significantly, thus enabling the analysis of complex, humid mixtures. In-line pre-concentration can improve sensitivity down to the ppqV range. Furthermore, the use of non-radioactive ionisation sources in the near future could gain acceptance and will avoid legal restrictions...
September 18, 2018: Analytica Chimica Acta
Florina-Maria Copaciu, Dorina Simedru, Maria-Virginia Coman
In the present work, a procedure to determine three textile azo dyes, chromium-complexes [Nylosan Dark Brown (NDB), Lanasyn Dark Brown (LDB), and Lanasyn Red (LR)], from wastewater using solid-phase extraction (SPE) followed by LC-electrospray ionization negative mode tandem mass spectrometry (LC-ESI(-)-MS/MS) has been developed. The extraction/concentration and recovery degree of these dyes from liquid matrices were done on Strata WAX/NH₂ cartridges. The chromatographic separation was performed using a Luna C18 (2) 100Å column by isocratic elution with a methanol-acetonitrile-water (0...
May 18, 2018: Journal of AOAC International
Stephen Whitelam
We describe a simple method that can be used to sample the rare fluctuations of discrete-time Markov chains. We focus on the case of Markov chains with well-defined steady-state measures, and derive expressions for the large-deviation rate functions (and upper bounds on such functions) for dynamical quantities extensive in the length of the Markov chain. We illustrate the method using a series of simple examples, and use it to study the fluctuations of a lattice-based model of active matter that can undergo motility-induced phase separation...
March 2018: Physical Review. E
Hyungjoon Soh, Meesoon Ha, Hawoong Jeong
We revisit the slow-bond (SB) problem of the one-dimensional (1D) totally asymmetric simple exclusion process (TASEP) with modified hopping rates. In the original SB problem, it turns out that a local defect is always relevant to the system as jamming, so that phase separation occurs in the 1D TASEP. However, crossover scaling behaviors are also observed as finite-size effects. In order to check if the SB can be irrelevant to the system with particle interaction, we employ the condensation concept in the zero-range process...
March 2018: Physical Review. E
P Sprenger, M A Hoefer, G A El
A notion of hydrodynamic optical soliton tunneling is introduced in which a dark soliton is incident upon an evolving, broad potential barrier that arises from an appropriate variation of the input signal. The barriers considered include smooth rarefaction waves and highly oscillatory dispersive shock waves. Both the soliton and the barrier satisfy the same one-dimensional defocusing nonlinear Schrödinger (NLS) equation, which admits a convenient dispersive hydrodynamic interpretation. Under the scale separation assumption of nonlinear wave (Whitham) modulation theory, the highly nontrivial nonlinear interaction between the soliton and the evolving hydrodynamic barrier is described in terms of self-similar, simple wave solutions to an asymptotic reduction of the Whitham-NLS partial differential equations...
March 2018: Physical Review. E
Muhammed Rasi M, K P Zuhail, Arun Roy, Surajit Dhara
The competing effect of surface anchoring of dispersed microparticles and elasticity of nematic and cholesteric liquid crystals has been shown to stabilize a variety of topological defects. Here we study a pair of colloidal microparticles with homeotropic and planar surface anchoring across N-SmA-SmC phase transitions. We show that below the SmA-SmC phase transition the temperature dependence of interparticle separation (D) of colloids with homeotropic anchoring shows a power-law behavior; D∼(1-T/T_{AC})^{α}, with an exponent α≈0...
March 2018: Physical Review. E
Su-Chan Park
We investigate the origin of the difference, which was noticed by Fey et al. [Phys. Rev. Lett. 104, 145703 (2010)PRLTAO0031-900710.1103/PhysRevLett.104.145703], between the steady state density of an Abelian sandpile model (ASM) and the transition point of its corresponding deterministic fixed-energy sandpile model (DFES). Being deterministic, the configuration space of a DFES can be divided into two disjoint classes such that every configuration in one class should evolve into one of absorbing states, whereas no configurations in the other class can reach an absorbing state...
March 2018: Physical Review. E
Ulrika Håkansson, Reidulf Watten, Kerstin Söderström, Finn Skårderud, Merete Glenne Øie
Mothers with a substance use disorder (SUD) are at risk for maladaptive parenting practices, and have heightened likelihood of having experienced childhood adversity themselves. In addition, parental reflective functioning (PRF), a capacity underlying sensitive caregiving, is often low in mothers with SUD. This study examines the relationship between PRF and aversive (emotional, physical, sexual abuse and neglect) and adaptive (safety and competence) experiences, in different developmental phases (early childhood, latency, and adolescence) in mothers with a SUD...
May 15, 2018: Child Abuse & Neglect
Udani L Kathriarachchi, Sagar S Vidhate, Naser Al-Tannak, Alison H Thomson, Michael J J da Silva Neto, David G Watson
A method was developed for the determination of amoxicillin and metronidazole in human serum. The procedure used was hydrophilic interaction chromatography (HILIC) followed by mass spectrometric (MS) detection. Chromatographic separation was achieved on a ZIC-HILIC column and the mobile phase consisted of a mixture of 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in acetonitrile. The method was validated with regard to selectivity, accuracy, precision, calibration, lower limit of quantification (LOQ), extraction recovery and matrix effect...
May 15, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Mahdi Akbari, Mojtaba Shariaty-Niassar, Takeshi Matsuura, Ahmad Fauzi Ismail
Although polymeric membranes find important role in water and waste water treatment in recent years, their fouling is still an important problem. Application of hydrophilic nanoparticles (NPs) is one of the proposed methods for reducing fouling of membranes but their dispersion and stability in hydrophobic polymer matrix is challenging. In this study Janus functionalization of the NPs was introduced as a promising technique toward achieving this goal. Polysulfone (PSf) membranes containing various concentrations of graphene oxide (GO) nanosheets and Janus graphene oxide (Janus GO) nanosheets (as additives) were fabricated via phase inversion...
May 15, 2018: Journal of Colloid and Interface Science
Xuemei Liu, Pei Hu, Yongsheng Wang, Xizhu Wang, Jinghua Huang, Jin Li, Cheng Li, Hongyun Wang, Ji Jiang
Monocyte locomotion inhibitory factor (MLIF, Met-Gln-Cys-Asn-Ser), a pentapeptide with anti-inflammatory activity, was developed for neural protection in acute ischemic stroke. Determination of MLIF in human plasma samples is of great importance for pharmacokinetic evaluation in clinical studies. A reliable and sensitive method based on ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was established for the measurement of MLIF in human plasma. Instability of peptide in matrix was the primary challenge in method development, which was properly resolved by addition of acidification reagents like sulfuric acid...
April 10, 2018: Journal of Pharmaceutical and Biomedical Analysis
Eric Christopher Novak, Niina Jalarvo, Sudipta Gupta, Kunlun Hong, Stephan Förster, Takeshi Egami, Michael Ohl
Plastic crystals are a promising candidate for solid state ionic conductors. In this work, quasielastic neutron scattering is employed to investigate the center of mass diffusive motions in two types of plastic crystalline cyclic alcohols: cyclohexanol and cyclooctanol. Two separate motions are observed which are attributed to long range translational diffusion (α-process) and cage rattling (fast β-process). Residence times and diffusion coefficients are calculated for both processes, along with the confinement distances for the cage rattling...
May 18, 2018: Journal of Physical Chemistry. B
Joseph Massarella, Jay Ariyawansa, Jaya Natarajan, Stephan Francke, Thomas Murtaugh, Byron DeLemos, Subusola Vaughan, Sergio Fonseca
We evaluated the effects of therapeutic and supratherapeutic doses of tramadol hydrochloride on the corrected QT (QTc) interval in healthy adults (aged 18-55 years) in a randomized, phase I, double-blind, placebo- and positive-controlled, multiple-dose, 4-way crossover study. Participants were randomized to receive 1 of 4 treatments (A-D), 1 each in 4 treatment periods (1-4), separated by a washout period (7-15 days). Treatment A comprised tramadol 400 mg (therapeutic dose) on days 1 through 3, tramadol 100 mg and moxifloxacin-matched placebo on day 4, and placebo on all 4 days...
May 18, 2018: Clinical Pharmacology in Drug Development
Bolin Zhu, Miaoduo Deng, Yaqi Yao, Jia Yu, Qing Li
Immobilized polysaccharide-based columns showed excellent enantioselectivity in normal phase separation mode. In this work, enantioseparation abilities of four immobilized polysaccharide-derived chiral stationary phases (Chiralpak IA, Chiralpak IB, Chiralpak IC and Chiralpak ID) toward fifteen azole compounds were evaluated. Separation was carried out using n-hexane as mobile phase with ethanol, 1-propanol, 1-butanol and 2-propanol as modifiers. And twelve compounds have achieved baseline separation with the resolutions ranging between 2...
May 18, 2018: Electrophoresis
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