Search results for "Resolution"

Growth of fibrous aggregates of silica nanoparticles: Fibre growth by mimicking the biogenic silica patterning processes

2009

We describe the self-assembly of discrete SiO2 nanofibers via grafting of silicatein side chains to a polymer backbone. The covalent binding of silicatein to the backbone of the polymer is based on the affinity of the nitrilotriacetic acid (NTA) side chain, which serves as a ligand for the immobilization of His-tagged silicatein. The surface charge and the bulkiness of the protein moieties prevent the entropically favoured coil formation of the polymer and force it to adopt an open chain structure after hydrolysis of the silica precursors. The probes were characterized by scanning force microscopy (SFM) and optical light microscopy. Surface complexation of the resulting silica nanoparticles…

Chapter 2 Single molecule spectroscopy of multichromophoric dendrimers at room and liquid helium temperatures

2004

Publisher Summary This chapter discusses the single molecule spectroscopy of multichromophoric dendrimers at room and liquid helium temperatures. Single molecule spectroscopy has become an important tool for the optical study of the electronic interactions of proximate chromophores as the electronic interactions can be studied without averaging over the properties of an intrinsically heterogeneous ensemble. Single perylenemonoimide (PMI) chromophores are selectively addressed in the frequency domain within spatially isolated multichromophoric dendrimers, which are dispersed in a polymer film. Although the chromophores are interacting, they still can be addressed separately. This feature in …

Determination of major carotenoids in vegetables by capillary electrochromatography.

2006

A simple and rapid method for the isocratic separation and determination of carotenoids (carotenes and xanthophylls) in vegetables by CEC is described. The capillary column (100 microm ID, 25 cm effective length) was packed with 3 microm Hypersil ODS particles. The optimized mobile phase contained 60% ACN, 35% THF and 5% of a 5 mM Tris aqueous buffer of pH 8. beta-Carotene, lycopene and lutein were separated with efficiencies of 66 000-128 000 plates/m within a short time (less than 12 min for the last peak eluted, 13/13'-cis-beta-carotene). An excellent resolution of the three carotenoids, as well as partial resolution of their geometrical isomers, was achieved. Application to the determin…

UV optical record and electron beam lithography in polymer films

2012

Possibility of UV optical record and electron beam lithography in different type of organic polymer films was studied. Mechanisms of molecular structure changes: photoisomerization, destruction, cross-linking and oxidation have been discussed. The results of UV illumination of polyurethanes, polyacrilates, and some block-copolymers are described. The element analysis of polyisoprene block copolymer was performed before and after UV illumination, and the changes in transmission spectra of the polymer film were measured. The resolution of electron beam lithography on polymer films was studied. In the polyisoprene block copolymer film the oxidation polymerization was ascertain at UV-illuminati…

Quantitative measurements of non-covalent interactions with diamond based magnetic imaging

2018

We present a technique employing dielectrophoretic (DEP) manipulation of surface immobilized complexes integrated with a magnetic imaging platform based on nitrogen-vacancy (NV) centers in diamond for the quantitative measurements of non-covalent interactions. The interdigitated microelectrodes closely spaced to the functionalized surface of the diamond plate provide a wide range of applied DEP forces for noninvasive manipulation of various molecular interactions, while the NV layer under the surface reports the unbinding dynamics. Given that biological samples do not present significant magnetic background and do not screen magnetic fields, our approach has many advantages over the fluores…

Normal-phase (temperature gradient) interaction chromatography – A powerful tool for the characterisation of high molecular weight chain-end function…

2015

Abstract We report here, for the first time, quantitative analysis of end-group functionalisation and the extent of end-group modification of polymers with molar mass up to 200,000 g mol −1 , using a combination of isothermal and temperature gradient interaction chromatography. At such high molecular weights, other common analytical techniques such as MALDI-ToF-MS and NMR spectroscopy are simply unable to offer any quantitative insight into the end-group functionality of polymers. Thus, normal phase isothermal interaction chromatography (NP-IIC) has been used to characterise a series of polystyrene samples, with identical molar mass (c. 90,000 g mol −1 ), each carrying a single chain-end fu…

Asymmetric One-Pot Synthesis of (3R,3aS,6aR)-Hexahydrofuro[2,3-b]furan-3-ol: A Key Component of Current HIV Protease Inhibitors

2017

A concise and efficient synthesis of (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-ol, a key building block for several clinical and experimental HIV protease inhibitors including the highly important drug darunavir, was achieved via a one-pot procedure using furan and Cbz-protected glycol aldehyde as starting materials. A [2+2]-photocycloaddition between both reactants which can be prepared from wood-based starting materials according to the principles of xylochemistry, followed by hydrogenation and lipase-catalyzed kinetic resolution afforded the target compound in high yield and up to 99% ee.

1996

The major new developments in electron crystallography and high resolution imaging of organic molecules are discussed. The aim is to show that the recent rapid advances in computer technology have made it possible to analyze molecules at a level or resolution which was impossible less than a decade ago, thus bringing the concept of molecular design to produce specific physical properties much nearer to realization

Microstructure of a Discotic Polymer as Revealed by Electron Diffraction and High-Resolution Imaging

1989

Analysis of the metabolic switch induced by the spirulina peptide SP6 in high fat diet ApoE-/-mice model: A direct infusion FT-ICR-MS based approach

2021

Atherosclerosis, dyslipidemia and hypertension are comorbid diseases often found in combination. Among different pharmacological approaches the employment of natural multifunctional peptides is an attractive option as side therapy. Mass spectrometry-based metabolomics provide valuable information on metabolic changes and can be useful to elucidate peptide pharmacodynamics. In this this work we performed a preliminary investigation on the potential effect of a recently characterized Spirulina platensis peptide named SP6 (GIVAGDVTPI) on the modulation of metabolism in a high fat diet ApoE-/- mice atherosclerotic model. A direct infusion Fourier transform ion cyclotron resonance mass spectrome…