Search results for "quantum coherence"

1H and 13C HR-MAS spectroscopy of intact biopsy samples ex vivo and in vivo 1H MRS study of human high grade gliomas.

2004

High-resolution magic angle spinning (HR-MAS) one- and two-dimensional 1H and 13C nuclear magnetic resonance (NMR) spectroscopy has been used to study intact glioblastoma (GBM) brain tumour tissue. The results were compared with in vitro chemical extract and in vivo spectra. The resolution of 1H one-dimensional, 1H TOCSY and 13C HSQC HR-MAS spectra is comparable to that obtained on perchloric extracts. 13C HSQC HR-MAS spectra have been particularly useful for the identification of 37 different metabolites in intact biopsy tumours, excluding water and DSS components. To our knowledge, this is the most detailed assignment of biochemical compounds obtained in intact human tissue, in particular…

The novel structure of the core oligosaccharide backbone of the lipopolysaccharide from the Plesiomonas shigelloides strain CNCTC 8089 (serotype O13)

2013

The new structure of the core oligosaccharide of Plesiomonas shigelloides CNCTC 80/89 (serotype O13) lipopolysaccharide has been investigated by chemical methods, (1)H and (13)C NMR spectroscopy and matrix-assisted laser-desorption/ionization time of flight (MALDI-TOF). It was concluded that the core oligosaccharide of P. shigelloides CNCTC 80/89 is a nonasaccharide with the following structure: The position of glycine was determined by MALDI-TOF MS/MS analyses.

Effects of nucleotide binding to LmrA: A combined MAS-NMR and solution NMR study

2015

ABC transporters are fascinating examples of fine-tuned molecular machines that use the energy from ATP hydrolysis to translocate a multitude of substrates across biological membranes. While structural details have emerged on many members of this large protein superfamily, a number of functional details are still under debate. High resolution structures yield valuable insights into protein function, but it is the combination of structural, functional and dynamic insights that facilitates a complete understanding of the workings of their complex molecular mechanisms. NMR is a technique well-suited to investigate proteins in atomic resolution while taking their dynamic properties into account…

Steroidal saponins from the fruits of Solanum torvum

2013

Abstract Seven steroidal glycosides have been isolated from the fruits of Solanum torvum Swartz. Their structures were established by 2D NMR spectroscopic techniques ( 1 H, 1 H-COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectrometry as (25 S )-26-(β- d -glucopyranosyloxy)-3-oxo-5α-furost-20(22)-en-6α-yl- O -β- d -xylopyranoside ( 1 ), (25 S )-26-(β- d -glucopyranosyloxy)-3-oxo-22α-methoxy-5α-furostan-6α-yl -O -β- d -xylopyranoside ( 2 ), (25 S )-26-(β- d -glucopyranosyloxy)-3β-hydroxy-22α-methoxy-5α-furostan-6α-yl- O -α- l -rhamnopyranosyl-(1 → 3)-β- d -glucopyranoside ( 3 ), (25 S )-3β-hydroxy-5α-spirostan-6α-yl- O -β- d -xylopyranoside ( 4 ), (25 S )-3-oxo-5α-spirostan-6α-yl- O -β- d -x…

Triterpene Saponins from Tupidanthus calyptratus

2001

Five new bisdesmosidic saponins (1--5) were isolated from the aerial parts of Tupidanthus calyptratus. Their structures were determined by (1)H--(1)H correlation spectroscopy (COSY, TOCSY, ROESY) and (1)H--(13)C correlation (HSQC, HMBC) NMR experiments, FABMS, and chemical data.

High-resolution solution NMR structure of the Z domain of staphylococcal protein A

1997

Staphylococcal protein A (SpA) is a cell-wall-bound pathogenicity factor from the bacterium Staphylococcus aureus. Because of their small size and immunoglobulin (IgG)-binding activities, domains of protein A are targets for protein engineering efforts and for the development of computational approaches for de novo protein folding. The NMR solution structure of an engineered IgG-binding domain of SpA, the Z domain (an analog of the B domain of SpA), has been determined by simulated annealing with restrained molecular dynamics on the basis of 671 conformational constraints. The Z domain contains three well-defined alpha-helices corresponding to polypeptide segments Lys7 to Leu17 (helix 1), G…

Activation of indistinguishability-based quantum coherence for enhanced metrological applications with particle statistics imprint

2022

Quantum coherence, an essential feature of quantum mechanics allowing quantum superposition of states, is a resource for quantum information processing. Coherence emerges in a fundamentally different way for nonidentical and identical particles. For the latter, a unique contribution exists linked to indistinguishability that cannot occur for nonidentical particles. Here, we experimentally demonstrate this additional contribution to quantum coherence with an optical setup, showing that its amount directly depends on the degree of indistinguishability, and exploiting it in a quantum phase discrimination protocol. Furthermore, the designed setup allows for simulating fermionic particles with p…

Heteronuclear NMR Applications (Y–Cd)*

1999

Secondary metabolites from the roots of Paronychia chionaea

2011

Two novel secondary metabolites, compounds (1–2) were isolated from the roots of Paronychia chionaea. On the basis of spectroscopic data including 1D and 2D NMR experiments (COSY, TOCSY, HSQC, and HMBC), and mass spectroscopy, their structures were established as 6- C-[α-L-arabinopyranosyl-(1→2)-β-D-glucopyranosyl]-7- O-[β-D-glucopyranosyl]-luteolin 3′-methyl ether (1), and 2-(methoxy)-2-(3,5-dimethoxy 4-hydroxyphenyl)-ethane-1,2-diol 1- O-β-D-glucopyranoside (2).

Phytochemistry of Weigela x “kosteriana variegata” (Caprifoliaceae)

2018

One new triterpene glycoside 3- O-β-D-xylopyranosyl-(1→4)-[β-D-glucopyranosyl-(1→3)]-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid, was isolated from Weigela x “kosteriana variegata” (Caprifoliaceae), with three known ones. Their structures were characterized by a combination of mass spectrometry and 1D and 2D NMR spectrocopic techniques including 1H- and 13C NMR, COSY, TOCSY, NOESY, HSQC, and HMBC experiments. The toxicological properties of some glycosides were determined with a zebrafish-based assay. The results show that the most active compounds were toxic to the larvae in the range of 1 μM.