scholarly journals Positional Isomerization of Phenylethanoid Glycosides from Magnolia officinalis

2016 ◽  
Vol 11 (12) ◽  
pp. 1934578X1601101 ◽  
Author(s):  
Zhenzhen Xue ◽  
Hua Li ◽  
Bin Yang
Keyword(s):  
Exposure Time ◽  
Critical Role ◽  
Phenylethanoid Glycosides ◽  
Positional Isomerization ◽  
Solvent Type ◽  
Magnolia Officinalis ◽  
Final Purification

Positional isomerization, an inducement leading to instability of phenylethanoid glycosides (PhGs) containing the caffeoyl moiety linked to C-3/4 of the central saccharide, is reported. Magnolosides M, A and F from Magnolia officinalis were found to be transformed into their isomers magnolosides A, D, M and B, respectively, which indicated that PhGs containing the caffeoyl moiety linking to C-3/4 of the central saccharide were unstable, and the caffeoyl group could be transferred to either C-4/3 or C-6 of the central saccharide. In addition, among the factors of temperature, solvent type and exposure time in solvent, temperature was found to play a critical role in initiation of positional isomerization of PhGs. In order to retard this isomerization, the temperature should be lower than 40°C during the final purification stages of PhGs.

Profiling and isomer recognition of phenylethanoid glycosides from Magnolia officinalis based on diagnostic/holistic fragment ions analysis coupled with chemometrics

2020 ◽  
Vol 1611 ◽  
pp. 460583
Author(s):  
Zhenzhen Xue ◽  
Changjiangsheng Lai ◽  
Liping Kang ◽  
Akira Kotani ◽  
Hideki Hakamata ◽  
...  
Keyword(s):  
Phenylethanoid Glycosides ◽  
Fragment Ions ◽  
Magnolia Officinalis

scholarly journals Total phenylethanoid glycosides and magnoloside IafromMagnolia officinalisvar.bilobafruits inhibit ultraviolet B-induced phototoxicity and inflammation through MAPK/NF-κB signaling pathways

RSC Advances ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 4362-4371 ◽  
Author(s):  
Lanlan Ge ◽  
Ling Chen ◽  
Qigui Mo ◽  
Gao Zhou ◽  
Xiaoshan Meng ◽  
...  
Keyword(s):  
European Union ◽  
United Kingdom ◽  
Traditional Medicine ◽  
Signaling Pathways ◽  
Food Additive ◽  
Ultraviolet B ◽  
The European Union ◽  
Phenylethanoid Glycosides ◽  
The United Kingdom ◽  
Magnolia Officinalis

Magnolia officinalisvar.bilobais used as a traditional medicine in China and as a food additive in the United Kingdom and the European Union.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Dexamethasone Effect on Embryonic Chick Respiratory Epithelium

1982 ◽  
Vol 40 ◽  
pp. 248-249
Author(s):  
M.R. Richter ◽  
R.V. Blystone
Keyword(s):  
Lung Development ◽  
Critical Role ◽  
Respiratory Epithelium ◽  
Chick Embryos ◽  
Embryonic Chick ◽  
White Leghorn ◽  
Lung Maturation ◽  
Synthetic Analogs ◽  
Lung Physiology ◽  
Avian Lung

Dexamethasone and other synthetic analogs of corticosteroids have been employed clinically as enhancers of lung development. The mechanism(s) by which this steroid induction of later lung maturation operates is not clear. This study reports the effect on lung epithelia of dexamethasone administered at different intervals during development. White Leghorn chick embryos were used so as to remove possible maternal and placental influences on the exogenously applied steroid. Avian lung architecture does vary from mammals; however, respiratory surfactant produced by the lung epithelia serves an equally critical role in avian lung physiology.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

An atomic resolution study of a carbide phase in platinum

1992 ◽  
Vol 50 (1) ◽  
pp. 20-21
Author(s):  
M.J. Witcomb ◽  
M.A. O'Keefe ◽  
CJ. Echer ◽  
C. Nelson ◽  
J.H. Turner ◽  
...  
Keyword(s):  
Solid Solution ◽  
Carbon Atom ◽  
Carbide Phase ◽  
Structural Changes ◽  
Critical Role ◽  
Alloy System ◽  
Atomic Resolution ◽  
Excess Carbon ◽  
Interstitial Carbon ◽  
Resolution Study

Under normal circumstances, Pt dissolves only a very small amount of interstitial carbon in solid solution. Even so, an appropriate quench/age treatment leads to the formation of stable Pt2C {100} plate precipitates. Excess (quenched-in) vacancies play a critical role in the process by accommodating the volume and structural changes that accompany the transformation. This alloy system exhibits other interesting properties. Due to a large vacancy/carbon atom binding energy, Pt can absorb excess carbon at high temperatures in a carburizing atmosphere. In regions rich in carbon and vacancies, another carbide phase, Pt7C which undergoes an order-disorder reaction was formed. The present study of Pt carburized at 1160°C and aged at 515°C shows that other carbides in the PtxC series can be produced.

Sign in / Sign up

Export Citation Format

Share Document