The US National Library of Medicine and National Institutes of Health manage PubMed.gov which comprises of more than 21 million records, papers, reports for biomedical literature, including MEDLINE, life science and medical journals, articles, reviews, reports and books. BioPortfolio aims to publish relevant information on published papers, clinical trials and news associated with users selected topics.
For example view all recent relevant publications on Epigenetics and associated publications and clincial trials.
A general procedure for the assembly of hetero-bifunctional cubic silsesquioxanes with diverse functionality and a perfectly controlled distribution of functional groups on the inorganic framework has been developed. The method is based on a two-step sequence of mono- and hepta-functionalization through the ligand-accelerated copper(I)-catalyzed azide-alkyne cycloaddition of a readily available octaazido cubic silsesquioxane. The stoichiometry of the reactants and the law of binomial distribution essentiall...
The S30 extract from E. coli BL21 Star (DE3) used for cell-free protein synthesis removes a wide range of α-amino acid protecting groups by cleaving α-carboxyl hydrazides; methyl, benzyl, tert-butyl, and adamantyl esters; tert-butyl and adamantyl carboxamides; α-amino form-, acet-, trifluoroacet-, and benzamides; and side-chain hydrazides and esters. The free amino acids are produced and incorporated into a protein under standard conditions. This approach allows the deprotection of amino acids to be carr...
Acetylcholinesterase (AChE) inhibition is one of the most currently available therapies for the management of Alzheimer's disease (AD) symptoms. In this context, NMR spectroscopy binding studies were accomplished to explain the inhibition of AChE activity by Salvia sclareoides extracts. HPLC-MS analyses of the acetone, butanol and water extracts eluted with methanol and acidified water showed that rosmarinic acid is present in all the studied samples and is a major constituent of butanol and water extracts....
The reactivity of the two diatomic congeneric systems [CO](.+) and [SiO](.+) towards methane has been investigated by means of mass spectrometry and quantum-chemical calculations. While [CO](.+) gives rise to three different reaction channels, [SiO](.+) reacts only by hydrogen-atom transfer (HAT) from methane under thermal conditions. A theoretical analysis of the respective HAT processes reveals two distinctly different mechanistic pathways for [CO](.+) and [SiO](.+) , and a comparison to the higher metal...
An Umpolung approach, in which a phosphorus ylide moiety was introduced to increase the electron density of the double bond, was developed to activate electron-deficient alkenes for reaction with electrophilic iron carbenes. In tandem with the Wittig reaction, the reactions of α,β-unsaturated esters with in situ generated Fecarbene complexes delivered formal CH insertion products through cyclopropanation/ring-opening reactions. DFT calculations and cross-experiments indicate that, in this process, t...
Heparan sulfates (HS) are a class of sulfated polysaccharides that function as dynamic biological regulators of the functions of diverse proteins. The structural basis of these interactions, however, remains elusive, and chemical synthesis of defined structures represents a challenging but powerful approach for unravelling the structure-activity relationships of their complex sulfation patterns. HS has been shown to function as an inhibitor of the β-site cleaving enzyme β-secretase (BACE1), a protease res...
The first catalytic enantioselective 1,3-dipolar cycloaddition of azomethine ylides to α-aminoacrylate catalyzed by a AgOAc/ferrocenyl oxazolinylphosphine (FOXAP) system was developed, which exhibits excellent exo- and enantioselectivity (92-99 % ee). This process provides efficient access to useful 4-aminopyrrolidine-2,4-dicarboxylic acid (APDC)-like compounds containing a unique quaternary α-amino acid unit.
Nanoporous organosilica membranes are successfully coated on porous alumina tubes and tested for desalination via membrane distillation. The membranes produced pure water (up to 13 kg m(-2) h(-1)) across an extreme range of salt concentrations (10-150 g L(-1) NaCl) at moderate temperatures (≤60 °C) without exhibiting the characteristic flux decay of competing materials.
Aggregation and dispersion behaviours of halloysite nanotubes (HNTs) were influenced by pH. The meso- and micro-porosity of halloysite were determined by N2 gas physisorption. The blocking and opening of halloysite nanotube pores with acid, neutral, and base treatment were detected in a micro- and mesoporous matrix of tunable porosity. The inner pores of HNTs were opened with base treatment, but were closed with acid or neutral treatment.
Porous Pt nanostructure decorated sulfur microparticles (Pt@S) are fabricated using sulfur as the template. The Pt@S electrode shows a higher volumetric specific capacity of 520 mA h cm(-3) and improved cyclability with only 15% capacity fading after 80 cycles at 0.1 C (167.5 mA g(-1)).
We developed a facile one-step method to produce ready-to-use quantum dots based on a peptide sequence containing a hexahistidine(his6-tag), poly(ethylene glycol) (PEG), and a functional group, which lead to stable and customized peptide-QDs conjugates that could serve as fluorescent nanoprobes for biological imaging and detection.
The application of a novel bipolar molecular glass in field-effect transistors leads to devices with photoinduced magnetoresistance (MR) sign change. In darkness a low external magnetic field increases the resistance (positive MR up to +0.1%), while a magnetic-field induced resistance decrease (negative MR up to -6.5%) can be achieved under illumination.
The partition of oligonucleotides and DNA staining dyes into a few hydrophobic ionic liquids has been studied, where the oligonucleotides remain in the aqueous phase and all the DNA staining dyes are extracted in the ionic liquid phase, allowing the separation of these two.
A spontaneous and controllable removal of condensed microdroplets at high supersaturation via self-propelled jumping is achieved by introducing a designed micropore array on a nanostructured superhydrophobic surface. The fabricated surface was demonstrated to delay the ice formation for 1 hour at -15 °C with a supersaturation of 6.97.
The mobility and rearrangement of the C4H7(+) system over Chabazite were studied using ab initio molecular dynamics. The results indicated the high mobility of the cations, which can rearrange within picosecond time intervals. Experimental studies of nucleophilic substitution supported the theoretical findings.
With the mediation of phosphine, the direct intramolecular coupling of two electrophiles - alkyl halides with electron-deficient olefins - has been successfully realized in an intramolecular conjugate addition manner. The reaction provides a new approach for the synthesis of chromans and relevant analogues.
Purine nucleotides are ubiquitous molecules that play vital roles in all kingdoms of life, not only as components of nucleic acids, but also participating in signaling and energy storage. Cellular pools of purines are maintained by the tight control of several complementary and sometimes competing processes including de novo biosynthesis, salvage and catabolism of nucleotides. While great strides have been made over the past sixty years in understanding the biosynthesis of purines, we are experiencing a ren...
The first solvent-free crystal structure of PCBM, an organic semiconductor widely used in solvent-free nanocrystalline films in plastic solar cells, is reported and its relevance to structure-property relationships discussed. The PCBM structure, obtained from o-dichlorobenzene solvates by solvent abstraction, was solved using powder diffraction, demonstrating this possibility for functionalized fullerenes.
The tri-functional coating synthesized via CVD copolymerization is comprised of distinguished anchoring sites of acetylene, maleimide, and ketone that can synergically undergo specific conjugation reactions to render surfaces with distinct biological functions, simultaneously. In addition, these tri-functional coatings can be fabricated in a micro-structured fashion on non-conventional surfaces.
A simple and highly efficient Rh/C catalyzed route for the cleavage of the C-O bond of aromatic ether at 80 °C in the presence of 0.5 MPa of H2 in the scCO2-water medium is reported; CO2 pressure and water play a key role under the tested conditions.
The Ru(ii)-H and water promoted asymmetric cleavage of 2,2'-pyridil to pyridine-2-carbaldehyde and unprecedented picolinic acid anion radical (PyCOOH(-)˙) complexes, which in solution produce H2 gas and diamagnetic picolinate complexes of ruthenium(ii) in moderate yields, is reported.
A novel substrate-controlled aldol reaction of a chiral isopropyl ketone is reported. The outstanding regioselective enolization by TiCl4-i-Pr2NEt provides a chelated enolate that can participate in highly diastereoselective additions to a wide array of aldehydes favouring the corresponding 2,5-syn adducts.
Herein we report the rational design of new phosphopeptides for control of nucleation, growth and aggregation of water-soluble, superparamagnetic iron-iron oxide core-shell nanoparticles. The use of the designed peptides enables a one-pot synthesis that avoids utilizing unstable or toxic iron precursors, organic solvents, and the need for exchange of capping agent after synthesis of the NPs.
We developed fast and readily applicable microarray chips to detect PSA by designing a novel conjugated polymer (energy donor) and combining it with on-chip peptide synthesis. The selective cleavage of a probing peptide labelled with a dye or a quencher (energy acceptor) produced a fluorescence sensory signal via fluorescent energy resonance transfer (FRET).
A G-quadruplex is identified which can exhibit two different motifs, respectively, corresponding to Na(+) and K(+). The relative amount of each motif is related to the Na(+)/K(+) ratio. Based on selective recognition of the G-quadruplex motifs by a cyanine dye aggregate, a method for both colorimetric and quantitative measurements of Na(+)/K(+) ratios is constructed.