Tunneling effects in the NMR spectrum of a spin in a symmetrical double-well potential

1987 ◽  
Vol 73 (3) ◽  
pp. 545-547
Author(s):  
Charles S Johnson
Keyword(s):  
Nmr Spectrum ◽  
Double Well Potential

Quantum ohmic dissipation : particle in an asymmetric double-well potential

1986 ◽  
Vol 47 (5) ◽  
pp. 757-766 ◽  
Author(s):  
C. Aslangul ◽  
N. Pottier ◽  
D. Saint-James
Keyword(s):  
Ohmic Dissipation ◽  
Double Well Potential

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

scholarly journals RETRACTED: Double well potential function and its optimization in the n-dimensional real space: part I

2015 ◽  
Vol 21 (3) ◽  
pp. NP64-NP65 ◽  
Author(s):  
Shu-Cherng Fang ◽  
David Yang Gao ◽  
Gang-Xuan Lin ◽  
Ruey-Lin Sheu ◽  
Wen-Xun Xing
Keyword(s):  
Potential Function ◽  
Real Space ◽  
Double Well Potential

Suppressing Chaos in a Nonideal Double-Well Oscillator Using an Based Electromechanical Damped Device

2014 ◽  
Vol 706 ◽  
pp. 25-34 ◽  
Author(s):  
G. Füsun Alişverişçi ◽  
Hüseyin Bayiroğlu ◽  
José Manoel Balthazar ◽  
Jorge Luiz Palacios Felix
Keyword(s):  
Numerical Simulations ◽  
Chaotic Dynamics ◽  
Duffing Oscillator ◽  
Vibration Energy ◽  
Vibration Absorber ◽  
Electrical System ◽  
Chaotic Vibration ◽  
System A ◽  
Ideal System ◽  
Double Well Potential

In this paper, we analyzed chaotic dynamics of an electromechanical damped Duffing oscillator coupled to a rotor. The electromechanical damped device or electromechanical vibration absorber consists of an electrical system coupled magnetically to a mechanical structure (represented by the Duffing oscillator), and that works by transferring the vibration energy of the mechanical system to the electrical system. A Duffing oscillator with double-well potential is considered. Numerical simulations results are presented to demonstrate the effectiveness of the electromechanical vibration absorber. Lyapunov exponents are numerically calculated to prove the occurrence of a chaotic vibration in the non-ideal system and the suppressing of chaotic vibration in the system using the electromechanical damped device.

scholarly journals Biotin-Containing Third Generation Glucoheptoamidated Polyamidoamine Dendrimer for 5-Aminolevulinic Acid Delivery System

2021 ◽  
Vol 22 (4) ◽  
pp. 1982 ◽  
Author(s):  
Aleksandra Kaczorowska ◽  
Małgorzata Malinga-Drozd ◽  
Wojciech Kałas ◽  
Marta Kopaczyńska ◽  
Stanisław Wołowiec ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Aminolevulinic Acid ◽  
Reactive Oxygen ◽  
Pamam Dendrimer ◽  
Variable Number ◽  
Amide Bond ◽  
Oxygen Species ◽  
Nmr Spectrum ◽  
Guest Molecules ◽  
Amine Groups

Polyamidoamine PAMAM dendrimer generation 3 (G3) was modified by attachment of biotin via amide bond and glucoheptoamidated by addition of α-D-glucoheptono-1,4-lacton to obtain a series of conjugates with a variable number of biotin residues. The composition of conjugates was determined by detailed 1-D and 2-D NMR spectroscopy to reveal the number of biotin residues, which were 1, 2, 4, 6, or 8, while the number of glucoheptoamide residues substituted most of the remaining primary amine groups of PAMAM G3. The conjugates were then used as host molecules to encapsulate the 5-aminolevulinic acid. The solubility of 5-aminolevulinic acid increased twice in the presence of the 5-mM guest in water. The interaction between host and guest was accompanied by deprotonation of the carboxylic group of 5-aminolevulinic acid and proton transfer into internal ternary nitrogen atoms of the guest as evidenced by a characteristic chemical shift of resonances in the 1H NMR spectrum of associates. The guest molecules were most likely encapsulated inside inner shell voids of the host. The number of guest molecules depended on the number of biotin residues of the host, which was 15 for non-biotin-containing glucoheptoamidated G3 down to 6 for glucoheptoamidated G3 with 8 biotin residues on the host surface. The encapsulates were not cytotoxic against Caco-2 cells up to 200-µM concentration in the dark. All encapsulates were able to deliver 5-aminolevulinic acid to cells but aqueous encapsulates were more active in this regard. Simultaneously, the reactive oxygen species were detected by staining with H2DCFDA in Caco-2 cells incubated with encapsulates. The amount of PpIX was sufficient for induction of reactive oxygen species upon 30-s illumination with a 655-nm laser beam.

scholarly journals Protein–Ligand Binding Volume Determined from a Single 2D NMR Spectrum with Increasing Pressure

2021 ◽  
Author(s):  
Gediminas Skvarnavičius ◽  
Zigmantas Toleikis ◽  
Vilma Michailovienė ◽  
Christian Roumestand ◽  
Daumantas Matulis ◽  
...  
Keyword(s):  
Ligand Binding ◽  
2D Nmr ◽  
Nmr Spectrum

scholarly journals Structural studies of phosphorylation-dependent interactions between the V2R receptor and arrestin-2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qing-Tao He ◽  
Peng Xiao ◽  
Shen-Ming Huang ◽  
Ying-Li Jia ◽  
Zhong-Liang Zhu ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Conformational Changes ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Interaction Sites ◽  
Receptor Interactions ◽  
Remote Sites ◽  
Genetic Code Expansion ◽  
G Protein Coupled ◽  
Interaction Change

AbstractArrestins recognize different receptor phosphorylation patterns and convert this information to selective arrestin functions to expand the functional diversity of the G protein-coupled receptor (GPCR) superfamilies. However, the principles governing arrestin-phospho-receptor interactions, as well as the contribution of each single phospho-interaction to selective arrestin structural and functional states, are undefined. Here, we determined the crystal structures of arrestin2 in complex with four different phosphopeptides derived from the vasopressin receptor-2 (V2R) C-tail. A comparison of these four crystal structures with previously solved Arrestin2 structures demonstrated that a single phospho-interaction change results in measurable conformational changes at remote sites in the complex. This conformational bias introduced by specific phosphorylation patterns was further inspected by FRET and 1H NMR spectrum analysis facilitated via genetic code expansion. Moreover, an interdependent phospho-binding mechanism of phospho-receptor-arrestin interactions between different phospho-interaction sites was unexpectedly revealed. Taken together, our results provide evidence showing that phospho-interaction changes at different arrestin sites can elicit changes in affinity and structural states at remote sites, which correlate with selective arrestin functions.

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