scholarly journals Chiral Stationary Phases and their Relationship with Enantiomer Structures in Enantioseparation Research of Analytical Laboratory

2017 ◽  
Vol 59 (1) ◽  
Author(s):  
Shun Yao
Keyword(s):  
Molecular Structure ◽  
Experimental Data ◽  
Mandelic Acid ◽  
Theoretical Study ◽  
Stationary Phases ◽  
Chiral Stationary Phases ◽  
The Other ◽  
Thermodynamic Mechanism ◽  
Mandelic Acid Derivatives ◽  
The Relationship

Chiral stationary phases (CSPs) and molecular structure of enantiomers are two independent but related aspects in enantioseparation, which are discussed on the basis of the experimental data from the previous study. Two enantioseparation experiments are performed to illustrate the relationship between enantiomer structures and chiral stationary phases, one is the resolution of mandelic acid derivatives and the other is about prasugrel. Thermodynamic mechanism and theoretical study with computational chemistry method is helpful to understand the interactions of enantiomer and CSPs.

Comparison of D,L-Mandelic Acid Resolution on Zeolite and Silica Supported Pirkle-Type Chiral Stationary Phases

2000 ◽  
Vol 134 (3-4) ◽  
pp. 205-213
Author(s):  
Lujza-P. Szabó ◽  
Làszló Szotyory ◽  
Dènes Kalló ◽  
Bélafiné-B. Katalin ◽  
Endre Nagy
Keyword(s):  
Mandelic Acid ◽  
Stationary Phases ◽  
Chiral Stationary Phases

scholarly journals In-Medium Strangeness Production and Hyperon-Potentials

2019 ◽  
Vol 26 ◽  
pp. 83
Author(s):  
T. Gaitanos ◽  
A. Violaris ◽  
L. Fabbietti ◽  
M. Steffen ◽  
J. Wirth
Keyword(s):  
Experimental Data ◽  
Neutron Star ◽  
Theoretical Study ◽  
Nuclear Astrophysics ◽  
The Other ◽  
Recent Experimental Data ◽  
Theoretical Treatment ◽  
Kaon Production ◽  
Microscopic Models ◽  
Open Issue

A hot topic of current research concerns the Equation of State (EoS) of nucleons and, in particular, of hyperons in dense nucleonic media. The study of the EoS at nucleon densities far beyond saturation has been initiated several decades ago, however, the behavior of the EoS for strangeness particles is still an open issue. The strangeness part of the EoS is very important not only for the physics of exotic (hyper)nuclei, but also crucial for nuclear astrophysics, e.g., neutron star physics.Here we present our recent investigations related to the theoretical treatment of in-medium hyperon-interactions as well as first preliminary experimental results from pion-induced reactions. The theoretical study is based on the well-established Non-Linear Derivative (NLD) model, which is extended to the strangeness sector via SU(6) symmetry arguments. It turns out that the NLD-predictions are consistent with microscopic models based on the chiral-EFT theory. On the other hand, recent experimental HADES-data on hyperon and kaon production from pion-induced reactions indicate sensitivities on the underlying in-medium hyperon potentials. We thus conclude that, the recent experimental data from pion-induced reactions will definitely set stringent constraints on the still less understood hyperon-potentials in nucleonic matter.

Preparation of MgB2 powder for ex situ tape with high Jc-B performance

2008 ◽  
Vol 23 (2) ◽  
pp. 486-493 ◽  
Author(s):  
Takayuki Nakane ◽  
Hiroaki Kumakura
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Critical Current Density ◽  
Heating Time ◽  
The Other ◽  
Ex Situ ◽  
Preparation Process ◽  
Powder Preparation ◽  
Preparation Conditions ◽  
The Relationship

The relationship between the preparation conditions of MgB2 powder and the performance of the critical current density (Jc) of an applied magnetic field (B) of the final ex situ tape produced from it was investigated. The pelletizing pressure of the precursor is crucially important for improving the Jc-B performance of ex situ tape. The higher the pressure, the greater the resulting Jc of the ex situ MgB2 tape. We have shown that the pelletizing pressure used for the precursor mixture during the powder preparation process affects the phases formed in the MgB2. On the other hand, the heating time used is effective in changing the slope of the Jc-B curve of the final tape. This is thought to be due to a change in the crystallinity of the prepared MgB2 powder. The experimental data gathered here will become the basis for investigating the establishment of a guideline for preparing the starting powder used for the manufacture of ex situ MgB2 tape.

scholarly journals Degradation of Fucoxanthin to Elucidate the Relationship between the Fucoxanthin Molecular Structure and Its Antiproliferative Effect on Caco-2 Cells

Marine Drugs ◽  
2018 ◽  
Vol 16 (8) ◽  
pp. 275 ◽  
Author(s):  
Shiro Komba ◽  
Eiichi Kotake-Nara ◽  
Wakako Tsuzuki
Keyword(s):  
Molecular Structure ◽  
The Other ◽  
Antiproliferative Effect ◽  
Polyene Chain ◽  
Detailed Structure ◽  
Partial Structure ◽  
Structure Activity ◽  
Entire Structure ◽  
Human Colorectal Carcinoma ◽  
The Relationship

Fucoxanthin has an antiproliferative effect on cancer cells, but its detailed structure–activity correlation has not yet been elucidated. To elucidate this correlation, fucoxanthin was degraded by ozonolysis. The degraded compounds of fucoxanthin obtained by ozonolysis were purified by HPLC and analyzed by NMR. The polyene chain of fucoxanthin was cleaved by ozonolysis, and the fucoxanthin was divided into two types of cyclohexyl derivatives, one with a β,γ-epoxy ketone group and the other with an allenic bond. In order to elucidate the structure–activity correlation, Caco-2 cells (human colorectal carcinoma) were treated with fucoxanthin degradation compounds. It was found that the entire structure of fucoxanthin is not essential for its antiproliferative effect and that even a partial structure exerts this effect.

scholarly journals Experimental study of the behaviour of mini-charge underwater explosion bubbles near different boundaries

2010 ◽  
Vol 651 ◽  
pp. 55-80 ◽  
Author(s):  
C. F. HUNG ◽  
J. J. HWANGFU
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Underwater Explosion ◽  
The Other ◽  
Predictive Index ◽  
Local Vibration ◽  
Cavitation Bubbles ◽  
Relative Value ◽  
Similarities And Differences ◽  
The Relationship

This work experimentally studies the behaviour of underwater explosion bubbles near different boundaries. The results are compared with theoretical and experimental data on cavitation bubbles. Although explosion and cavitation bubbles behave similarly on a macroscopic level, there are still some differences, most of which are from the explosive nature of the explosion bubble. The relationship between bubble migration and the Kelvin impulse, surface inertia m* and surface stiffness k* is investigated. We found that none of them comprehensively predicts the migration of both cavitation and explosion bubbles when boundary elasticity is considered. This elasticity should be considered as a relative value with respect to bubble size. On the other hand, the phase between local vibration of boundaries and the pulsation of bubbles could be a useful predictive index of bubble migration. When using research results developed for cavitation bubbles in relation to explosion bubbles, the material presented here may be useful for pointing out their similarities and differences.

scholarly journals Estimating the Thermal Conductivities and Elastic Stiffness of Carbon Nanotubes as a Function of Tube Geometry

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Z. H. Zhang ◽  
N. Yu ◽  
W. H. Chao
Keyword(s):  
Experimental Data ◽  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Present Model ◽  
Elastic Stiffness ◽  
The Other ◽  
Microstructural Parameters ◽  
The Relationship ◽  
Tube Geometry ◽  
Thermal Conductivities

The thermal conductivities and elastic properties of carbon nanotubes (CNTs) are estimated by using the double-inclusion model, which is based on rigorous elasticity approach. The model regards a CNT as one inclusion (the inner cylindrical void) embedded in the other (the outer coaxial single-crystal graphite shell). The concept of homogenization is employed, and vital microstructural parameters, such as CNT diameter, length, and aspect ratio, are included in the present model. The relationship between microstructure and thermal conductivities and elastic stiffness of CNTs is quantitatively characterized. Our analytical results, benchmarked by experimental data, show that the thermal conductivities and elastic stiffness of CNTs are strongly dependent on the diameter of CNT with little dependence on the length of CNT.

scholarly journals Crystal structure and theoretical study of N,N-bis[(5-chloro-2-oxo-2,3-dihydrobenzo[d]oxazol-3-yl)methyl]-2-phenylethanamine

2018 ◽  
Vol 74 (5) ◽  
pp. 757-760
Author(s):  
Abdullah Aydın ◽  
Zeynep Soyer ◽  
Mehmet Akkurt ◽  
Orhan Büyükgüngör
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Phenyl Ring ◽  
Theoretical Study ◽  
The Other ◽  
Dihedral Angles ◽  
Stacking Interactions ◽  
Compound C ◽  
The Mean

In the molecular structure of the title compound, C24H19Cl2N3O4, the three C atoms of the central N,N-dimethylmethanamine moiety are bonded to the N atoms of the two 5-chloro-1,3-benzoxazol-2(3H)-one groups and to the methyl C atom of the methylbenzene group. One of the nine-membered 2,3-dihydro-1,3-benzoxazole rings and the phenyl ring are almost parallel to each other, making a dihedral angle of 5.30 (18)°, but they are almost normal to the mean plane of the other nine-membered 2,3-dihydro-1,3-benzoxazole ring, subtending dihedral angles of 89.29 (16) and 85.41 (18)°, respectively. The crystal structure features C—H...O hydrogen bonds and π–π stacking interactions [centroid-to-centroid distances = 3.5788 (19) Å, slippage = 0.438 and 3.7773 (16) Å, and slippage = 0.716 Å].

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