The chromatographic behaviour of a new HPLC-stationary phase (Chromolith RP-18e) is described for separation of beta-blockers. The effects of the different chromatographic conditions (buffer system, pH value, content of organic modifier, injection volume and flow rate) on the separation behaviour were studied. At higher flow rates the peaks seemed to be more symmetrical than at lower flow rates. The use of buffer or salt in the mobile phase for this separation is found to be very essential and the counter-anion type of this buffer or salt significantly affected the retention behaviour of beta-blockers while the cation type did not play the same important role.
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http://dx.doi.org/10.1002/jssc.200600001 | DOI Listing |
Polymers (Basel)
December 2024
Civil Engineering Department, Lanzhou Jiaotong University, Lanzhou 730070, China.
This study investigates the effect of microstructural changes in polyurethane coatings on their water resistance properties. Polyurethane coatings with varying diluent contents were prepared and tested for water penetration resistance and mechanical property retention. The time-dependent behavior of water within the coatings at different immersion durations was analyzed using low-field nuclear magnetic resonance (NMR).
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Departamento de Química, Facultad de Ciencias Naturales, Matemáticas y Medio Ambiente, Universidad Tecnológica Metropolitana (UTEM), J. P. Alessandri 1242, Santiago 7800002, Chile.
A series of hydrophilic copolymers were prepared using 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) from free radical polymerization at different feed monomer ratios using ammonium persulfate (APS) initiators in water at 70 °C. The herbicide 2,4-dichlorophenoxy acetic acid (2,4-D) was grafted to Poly(HEMA--IA) by a condensation reaction. The hydrolysis of the polymeric release system, Poly(HEMA--IA)-2,4-D, demonstrated that the release of the herbicide in an aqueous phase depends on the polymeric system's pH value and hydrophilic character.
View Article and Find Full Text PDFNutrients
December 2024
Discipline of Nutrition and Dietetics, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road Grafton, Auckland 1011, New Zealand.
Background: Young women spend 50 min daily on social media (SM); thus, SM platforms are promising for health interventions. This study tested the feasibility and preliminary efficacy of the co-designed SM intervention the Daily Health Coach (DHC). The DHC is a 3-month healthy lifestyles intervention programme, targeting eating, physical activity, and social wellbeing behaviours in women aged 18-24, via the dissemination of health and nutrition content on social media platform Instagram.
View Article and Find Full Text PDFMolecules
December 2024
Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
Machine learning potential energy functions can drive the atomistic dynamics of molecules, clusters, and condensed phases. They are amongst the first examples that showed how quantum mechanics together with machine learning can predict chemical reactions as well as material properties and even lead to new materials. In this work, we study the behaviour of tungsten trioxide (WO) surfaces upon particle impact by employing potential energy surfaces represented by neural networks.
View Article and Find Full Text PDFMolecules
December 2024
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China.
G-quadruplex (G4), an important secondary structure of nucleic acids, is polymorphic in structure. G4 monomers can associate with each other to form multimers, which show better application performance than monomers in some aspects. G4 dimers, the simplest and most widespread multimeric structures, are often used as a representative for studying multimers.
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