scholarly journals Searching for a UV-filter in the eyes of high flying birds

2018 ◽  
Author(s):  
Malgorzata Zawadzka ◽  
Beatrix Ràcz ◽  
Dario Ambrosini ◽  
Carl Henrik Gørbitz ◽  
Jens Preben Morth ◽  
...  
Keyword(s):  
Aqueous Humor ◽  
High Field ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
High Altitudes ◽  
Chromatographic Purification ◽  
Uv Filter ◽  
Nmr Methods

AbstractAn ultraviolet (UV)-absorbing compound of unknown identity is present in the aqueous humor of geese and other birds flying at high altitudes. A goose aqueous humor extract, that was believed to contain the UV protective compound which was designated as “compound X”, was fractionated and examined using a variety of spectroscopic techniques including LC-MS and high field one- and two dimensional-NMR methods. A series of compounds were identified but none of them appeared to be the UV protective “compound X”. It may be that the level of the UV protective compound in goose aqueous humor is much less than the compounds identified in our investigation, or it may have been degraded by the isolation and chromatographic purification protocols used in our investigations.

scholarly journals Novel Ecdysteroids fromSerratula wolffii

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Attila Ványolós ◽  
Zoltán Béni ◽  
Miklós Dékány ◽  
András Simon ◽  
Mária Báthori
Keyword(s):  
Methanolic Extract ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
Nmr Methods ◽  
New Compounds ◽  
Ponasterone A

Two new and one known ecdysteroids were identified in the methanolic extract of the roots ofSerratula wolffii. The new compounds isolated were ponasterone A-22-apioside (1) and 3-epi-shidasterone (3), together with the known 3-epi-22-deoxy-20-hydroxyecdysone (2). The structures of compounds1–3were determined by extensive spectroscopic techniques, including one- and two-dimensional NMR methods.

scholarly journals Combining Mechanistic Modeling and Raman Spectroscopy for Monitoring Antibody Chromatographic Purification

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 683 ◽  
Author(s):  
Feidl ◽  
Garbellini ◽  
Luna ◽  
Vogg ◽  
Souquet ◽  
...  
Keyword(s):  
Experimental Data ◽  
Raman Spectroscopy ◽  
Estimation Procedure ◽  
Mechanistic Modeling ◽  
Spectroscopic Techniques ◽  
Chromatographic Purification ◽  
On Line ◽  
Filter Approach ◽  
Underlying Mechanisms ◽  
Combining Information

Chromatography is widely used in biotherapeutics manufacturing, and the corresponding underlying mechanisms are well understood. To enable process control and automation, spectroscopic techniques are very convenient as on-line sensors, but their application is often limited by their sensitivity. In this work, we investigate the implementation of Raman spectroscopy to monitor monoclonal antibody (mAb) breakthrough (BT) curves in chromatographic operations with a low titer harvest. A state estimation procedure is developed by combining information coming from a lumped kinetic model (LKM) and a Raman analyzer in the frame of an extended Kalman filter approach (EKF). A comparison with suitable experimental data shows that this approach allows for the obtainment of reliable estimates of antibody concentrations with reduced noise and increased robustness.

A Study of Methyl β-Xylobioside: An Illustrative Example of Two-Dimensional NMR Methods

1984 ◽  
Vol 3 (4) ◽  
pp. 513-524 ◽  
Author(s):  
William B. Wise ◽  
Philip E. Pfeffer ◽  
Pavol Ková
Keyword(s):  
Two Dimensional ◽  
Nmr Methods

HIGH FIELD PHASE DIAGRAM OF THE FIELD-INDUCED SUPERCONDUCTING STATE OF λ-(BETS)2FeCl4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3101-3104
Author(s):  
L. BALICAS ◽  
J. S. BROOKS ◽  
K. STORR ◽  
S. UJI ◽  
M. TOKUMOTO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Superconducting State ◽  
Ground State ◽  
Electrical Transport ◽  
High Field ◽  
Two Dimensional ◽  
Exchange Field ◽  
Organic Conductor ◽  
Field Phase ◽  
Antiferromagnetic Ground State

We investigate by electrical transport the field-induced superconducting state (FISC) in the organic conductor λ- (BETS) 2 FeCl 4. Below 4 K, antiferromagnetic-insulator, metallic, and eventually superconducting (FISC) ground states are observed with increasing in-plane magnetic field. The FISC state survives between 18 and 41 T, and can be interpreted in terms of the Jaccarino-Peter effect, where the external magnetic field compensates the exchange field of aligned Fe 3+ ions. We further argue that the Fe 3+ moments are essential to stabilize the resulting singlet, two-dimensional superconducting state. Here we provide experimental evidence indicating that this state, as well as the insulating antiferromagnetic ground state, is extremely sensitive to hydrostatic pressure.

scholarly journals Competitive Diels–Alder and ene addition of N-arylmaleimides to 7-dehydrocholesteryl acetate

1992 ◽  
Vol 70 (11) ◽  
pp. 2730-2744 ◽  
Author(s):  
William J. Leigh ◽  
Donald W. Hughes ◽  
D. Scott Mitchell
Keyword(s):  
Molecular Mechanics ◽  
Nmr Spectra ◽  
Benzene Solution ◽  
Diels Alder ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
A Minor ◽  
C Nmr ◽  
Alder Adduct ◽  
Ene Addition

Thermolysis of N-phenyl, N-para-biphenyl, and N-para, para′-terphenylmaleimide with 7-dehydrocholesteryl acetate in benzene solution at 200 °C yields mixtures of four cycloadducts in relative yields that are essentially independent of the maleimide substituent. The three major products are those of ene addition to C7 of the steroid with abstraction of the proton at C9 or C14. The α-endo-Diels-Alder adduct is formed as a minor product. The structures of the adducts have been elucidated on the basis of one- and two-dimensional 1H and 13C NMR spectroscopic techniques, including homonuclear 1H decoupling, NOE, 1H–1H COSY, heteronuclear 1H–13C shift correlation, and TOCSY 2-D experiments, and the results of molecular mechanics (MMX) calculations. The combination of these techniques has made it possible to almost completely assign the 1H and 13C NMR spectra for two of the ene adducts and the Diels–Alder adduct from reaction of 7-dehydrocholesteryl acetate with N-phenyl maleimide.

scholarly journals Ultrafast Exciton Dynamics in Two Dimensional Covalent Organic Frameworks Reveals Size Dependence to Exciton Diffusion

2020 ◽  
Author(s):  
Nathan C. Flanders ◽  
Matthew S. Kirschner ◽  
Pyosang Kim ◽  
Thomas Fauvell ◽  
Austin Evans ◽  
...  
Keyword(s):  
High Performance ◽  
Transient Absorption ◽  
Domain Size ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
Exciton Dynamics ◽  
Singlet Exciton ◽  
Exciton Diffusion ◽  
Absorption Studies ◽  
Exciton Annihilation

<p>Large singlet exciton diffusion lengths are a hallmark of high performance in organic based devices such as photovoltaics, chemical sensors, and photodetectors. In this study, exciton dynamics of a two-dimensional covalent organic framework, COF- 5, is investigated using ultrafast spectroscopic techniques. Following photoexcitation, the COF-5 exciton decays via three pathways: 1) excimer formation (4 ± 2 ps), 2) excimer relaxation (160 ± 40 ps), and 3) excimer decay (>3 ns). Excitation fluence-dependent transient absorption studies suggest that COF-5 has a relatively large diffusion coefficient (0.08 cm2/s). Furthermore, exciton-exciton annihilation processes are characterized as a function of COF-5 crystallite domain size in four different samples, which reveal domain- size dependent exciton diffusion kinetics. These results reveal that exciton diffusion in COF-5 is constrained by its crystalline domain size. These insights indicate the outstanding promise of delocalized excitonic processes available in 2D COFs, which motivate their continued design and implementation into optoelectronic devices. </p>

Sign in / Sign up

Export Citation Format

Share Document