126 research outputs found
Cyclic Octapeptides Composed of Two Glutathione Units Outperform the Monomer in Lead Detoxification
A rationally-designed scaffold of cyclic octapeptides composed of two units of the natural tripeptide glutathione (GSH) was optimized to strongly and selectively capture toxic lead ions (Pb(II)). Using state-of-the-art computational tools, a list of eleven plausible peptides was shortened to five analogs based on their calculated affinity to Pb(II) ions. We then synthesized and investigated them for their abilities to recover Pb-poisoned human cells. A clear pattern was observed from the inâ
vitro detoxification results, indicating the importance of cavity size and polar moieties to enhance metal capturing. These, together with the apparent benefit of cyclizing the peptides, improved the detoxification of the two lead peptides by approximately two folds compared to GSH and the benchmark chelating agents against Pb poisoning. Moreover, the two peptides did not show any toxicity and, therefore, were thoroughly investigated to determine their potential as next-generation remedies for Pb poisoning
Electronic structure of GdN, and the influence of exact exchange
GdN bulk is studied with the local density approximation, on the Hartree-Fock
level, and on the level of the hybrid functional B3LYP. A local basis set
formalism is used, as implemented in the present CRYSTAL06 release. It is
demonstrated that the code is technically capable of treating this system with
its 4f electrons explicitly, i.e. out of the core. The band structure at the
level of the local density approximation is in good agreement with earlier
calculations and is found to be half-metallic. The Hartree-Fock band structure
is insulating with a large gap. Interestingly, three solutions were found at
the B3LYP level. The lowest of them is insulating for majority spin, and the
Fermi surface for minority spin consists only of points, resulting in a very
low density of states around the Fermi level.Comment: to appear in J. Phys.: Condensed Matte
Synthesis of 5-azaandrostane-3β,17β-diol protected at the 17β-hydroxyl group
In the present paper, the preparation of 3β-hydroxy-17β-dimethyl- tert-butylsilyloxy-5-azaandrostane (15) in fourteen steps is described. B-nor-17-oxoandrost-5-en-3β-yl acetate (1) 1,2 was used as the starting material, which was transformed to the key intermediate of the synthesis, B-nor-17β-dimethyl-tert-butylsilyloxyandrost-4-en-3β-yl acetate (7)
Cutting tool tracking and recognition based on infrared and visual imaging systems using principal component analysis (PCA) and discrete wavelet transform (DWT) combined with neural networks
The implementation of computerised condition monitoring systems for the detection cutting toolsâ correct installation and fault diagnosis is of a high importance in modern manufacturing industries. The primary function of a condition monitoring system is to check the existence of the tool before starting any machining process and ensure its health during operation. The aim of this study is to assess the detection of the existence of the tool in the spindle and its health (i.e. normal or broken) using
infrared and vision systems as a non-contact methodology. The application of Principal Component Analysis (PCA) and Discrete Wavelet Transform (DWT) combined with neural networks are investigated using both types of data in order to establish an effective and reliable novel software program for tool tracking and health recognition. Infrared and visual cameras are used to locate and track the cutting tool during the machining process using a suitable analysis and image processing algorithms. The capabilities of PCA and Discrete Wavelet Transform (DWT) combined with neural networks are investigated in recognising the toolâs condition by comparing the characteristics of the tool to those of known conditions in the training set. The experimental results have shown high performance when using the infrared data in comparison to visual images for the selected image and signal processing algorithms
Ground-state properties of rutile: electron-correlation effects
Electron-correlation effects on cohesive energy, lattice constant and bulk
compressibility of rutile are calculated using an ab-initio scheme. A
competition between the two groups of partially covalent Ti-O bonds is the
reason that the correlation energy does not change linearly with deviations
from the equilibrium geometry, but is dominated by quadratic terms instead. As
a consequence, the Hartree-Fock lattice constants are close to the experimental
ones, while the compressibility is strongly renormalized by electronic
correlations.Comment: 1 figure to appear in Phys. Rev.
On the Chemical Origin of the Gap Bowing in (GaAs)1âxGe2x Alloys: A Combined DFTâQSGW Study
Motivated by the research and analysis of new materials for photovoltaics and by the possibility of tailoring their optical properties for improved solar energy conversion, we have focused our attention on the (GaAs)1âxGe2x series of alloys. We have investigated the structural properties of some (GaAs)1âxGe2x compounds within the local-density approximation to density-functional theory, and their optical properties within the Quasiparticle Self-consistent GW approximation. The QSGW results confirm the experimental evidence of asymmetric bandgap bowing. It is explained in terms of violations of the octet rule, as well as in terms of the orderâdisorder phase transition
Morphological Changes of Monolayers of Two Polymerizable Pyridine Amphiphiles upon Complexation with Cu(II) Ions at the AirâWater Interface
Lokale elektronische Korrelationen in Gadoliniumnitrid und anderen periodischen Systemen.
Performence of relativistic density functional and ab initio pseudopotential approaches for systems with high-spin multiplicities: Gadolinium diatomics GdX (X=H,N,O,F,P,S,Cl,Gd).
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