3,192 research outputs found
Photosynthetic properties assisted by the quantum entanglement in two adjacent pigment molecules
The quantum dynamics of entanglement is widely revealed in photosynthetic
light-harvesting complexes. Different from the previous work, we explore the
properties of exciton transport and photosynthesis assisted by the quantum
entanglement in two adjacent pigment molecules, which are measured by the
population dynamics behaviors, the - characteristics and by the output
power via a photosynthetic quantum heat engine (QHE) model. A more robust
exciton transport dynamic behavior is compared with those without quantum
entanglement, and the photosynthetic characteristics evaluated by the output
current and power were proved to be enhanced by the quantum entanglement at
different ambient temperatures. These results may point toward the possibility
for artificial photosynthetic nanostructures inspired by this quantum
biological systems.Comment: 11 pages, 4 figure
Characterization and identification of in vitro metabolites of (-)-epicatechin using ultra-high performance liquid chromatography-mass spectrometry
Purpose: To characterize and identify metabolites of (-)-epicatechin in microsomal fraction of rat hepatocytes (MFRHs). Methods: A single incubation of (-)-epicatechin (1 mL, 50 µg/mL) in MFRH (0.5 mg/mL) was used for the generation of metabolites. Thereafter, the sample was subjected to protein precipitation prior to analysis with ultra-high performance liquid chromatography coupled to linear ion-trap orbitrap mass spectrometry (UHPLC-LTQ-Orbitap MS). Results: Nine metabolites of (-)-epicatechin were characterized on the basis of high resolution mass measurement, MS spectra and literature data. Based on their structures, the major metabolic routes of (-)-epicatechin in MFRHs were identified as hydroxylation, dihydroxylation and glycosylation. Conclusion: This is the first report on metabolites of (-)-epicatechin in MFRHs, and it is helpful in gaining deeper insight into the metabolism of (-)-epicatechin in vivo. The results will also provide guidance in research on the pharmacokinetics of new drugs. Keywords: (-)-Epicatechin, Metabolites, Hydroxylation, Dihydroxylation, Glycosylation, Rat liver microsomes, Pharmacokinetic studie
(E)-N′-(3,4-DimethoxyÂbenzylÂidene)-2,4-dihydroxyÂbenzohydrazide methanol solvate
The title compound, C16H16N2O5·CH3OH, was obtained from a condensation reaction of 3,4-dimethoxyÂbenzaldehyde and 2,4-dihydroxyÂbenzohydrazide. The non-H atoms of the Schiff base molÂecule are approximately coplanar (r.m.s. deviation = 0.043 Å) and the dihedral angle between the two benzene rings is 1.6 (1)°. The molÂecule adopts an E configuration with respect to the C=N double bond. An intraÂmolecular O—H⋯O hydrogen bond is observed. The Schiff base and methanol molÂecules are linked into a two-dimensional network parallel to (10) by interÂmolecular N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds
Baseline elevated Lp-PLA2 is associated with increased risk for re-stenosis after stent placement
BACKGROUND: Lipoprotein associated phospholipase A2 (Lp-PLA2) is a novel biomarker for cardiovascular risk prediction. Whether increased Lp-PLA2 level is associated with re-stenosis after stent-placement is unclear. METHODS: Totally 326 participants eligible for stent-placement were enrolled and divided into two groups according to baseline Lp-PLA2 levels (named normal and elevated groups). Baseline characteristics and clinical outcomes were compared between normal and elevated groups. The relationships between Lp-PLA2 and other risk factors with re-stenosis were evaluated. RESULTS: Only the between-group difference of Lp-PLA2 was significant (123.2 ± 33.6 ng/mL vs 336.8 ± 85.4 ng/mL, P < 0.001) while other demographic and clinical characteristics between these two groups were comparable. Approximately 55.1% and 58.5% of participants in normal and elevated groups presented with acute coronary syndrome, and the percentage of tri-vessels stenoses was significantly higher in elevated group (40.8% vs 32.1%, P = 0.016). Nearly 96.0% and 94.0% of participants in normal and elevated Lp-PLA2 groups were placed with drug-eluting stents, and the others were with bare-metal stents. After 1 year’s follow-up, the incidence of clinical end-points was comparable (13.3% vs 15.4%, P = 0.172). Nevertheless, the incidence of re-stenosis was marginally higher in elevated Lp-PLA2 group (8.5% versus 4.6%, P = 0.047). With multivariate analysis, after adjustment for other risk factors, Lp-PLA2 remained an independent predictor for re-stenosis with a hazard ratio of 1.140. No synergistic effect between Lp-PLA2 and other risk factors for re-stenosis was found. CONCLUSION: Increased Lp-PLA2 level is associated with an increased risk of re-stenosis. Lp-PLA2 assessment may be useful in predicting subjects who are at increased risk for re-stenosis
2-Amino-4-tert-butyl-5-(2,4-dichloroÂbenzÂyl)thiaÂzol-3-ium bromide
The asymmetric unit of the title compound, C14H17Cl2N2S+·Br−, contains one cation and two Br− ions with site symmetry . The dihedral angle between the planes of the thiaÂzol and the dichloroÂphenyl rings is 77.8 (6)°. In the crystal, the ions are connected by N–H⋯Br hydrogen bonds
A yolk-albumen-shell structure of mixed Ni-Co oxide with an ultrathin carbon shell for high-sensitivity glucose sensors
Altres ajuts: ICN2 is funded by the CERCA Programme/Generalitat de Catalunya. Part of the present work has been performed in the framework of Universitat Autònoma de Barcelona Materials Science PhD program. TZ has received funding from the CSC-UAB PhD scholarship program.Non-enzymatic glucose sensors based on different Co-Ni-C composite materials were developed by pyrolysis of bimetallic or single metal based metal-organic frameworks (MOFs). The structure and composition of the resulting materials were explored by XRD, nitrogen adsorption/desorption isotherms, SEM, HRTEM and STEM-EELS. The electrochemical performance of the bimetallic MOF derived novel yolk-albumen-shell structure of Ni-Co@C (YASNiCo@C) stands out from these materials. The YASNiCo@C electrode exhibited a sensitivity of 1964 μA cm-2 mM-1 with the detection limit of 0.75 μM, a linear range from 5 μM to 1000 μM and good stability for the detection of glucose. These promising electrochemical performances prove that YASNiCo@C is a promising material for glucose sensors. Moreover, the strategy outlined in this work for the design of MOF based nanomaterials can also be used beyond glucose sensors
Structure activity related, mechanistic, and modeling studies of gallotannins containing a glucitol-core and α-glucosidase
Gallotannins containing a glucitol core, which are only produced by members of the maple (Acer) genus, are more potent α-glucosidase inhibitors than the clinical drug, acarbose. While this activity is influenced by the number of substituents on the glucitol core (e.g. more galloyl groups leads to increased activity), the mechanisms of inhibitory action are not known. Herein, we investigated ligand–enzyme interactions and binding mechanisms of a series of ‘glucitol-core containing gallotannins (GCGs)’ against the α-glucosidase enzyme. The GCGs included ginnalins A, B and C (containing two, one, and one galloyl/s, respectively), maplexin F (containing 3 galloyls) and maplexin J (containing 4 galloyls). All of the GCGs were noncompetitive inhibitors of α-glucosidase and their interactions with the enzyme were further explored using biophysical and spectroscopic measurements. Thermodynamic parameters (by isothermal titration calorimetry) revealed a 1 : 1 binding ratio between GCGs and α-glucosidase. The binding regions between the GCGs and α-glucosidase, probed by a fluorescent tag, 1,1′-bis(4-anilino-5-naphthalenesulfonic acid), revealed that the GCGs decreased the hydrophobic surface of the enzyme. In addition, circular dichroism analyses showed that the GCGs bind to α-glucosidase and lead to loss of the secondary α-helix structure of the protein. Also, molecular modeling was used to predict the binding site between the GCGs and the α-glucosidase enzyme. This is the first study to evaluate the mechanisms of inhibitory activities of gallotannins containing a glucitol core on α-glucosidase
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