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Palladium-catalysed three component coupling of an alkenylbromide, isonitrile and an amine or alkoxide/phenoxide affords α,β-unsaturated-amidines and -imidates. 相似文献
2.
Results from Super-Kamiokande-I’s entire 1496 live days of solar neutrino data are presented, including the absolute flux,
energy spectrum, zenith angle (day/night) and seasonal variation. The possibility of MSW and vacuum oscillations is discussed
in light of these results. Results from the first 1289 days of Super-K-I’s atmospheric neutrino analysis are also presented,
including the evidence for νμ →ν
τ oscillations, against νμ → νsterile oscillations, and the current limits on proton decay. Finally, results based on 56 × 1019 protons on target are given for the K2K long-baseline neutrino oscillation experiment. 相似文献
3.
Microfluidic devices with their inherent advantages like the ability to handle 10−9 to 10−18 L volume, multiplexing of microchannels, rapid analysis and on-chip detection are proving to be efficient systems in various fields of life sciences. This review highlights articles published since 2010 that reports the use of microfluidic devices to separate biomolecules (DNA, RNA and proteins) using chromatography principles (size, charge, hydrophobicity and affinity) along with microchip capillary electrophoresis, isotachophoresis etc. A detailed overview of stationary phase materials and the approaches to incorporate them within the microchannels of microchips is provided as well as a brief overview of chemical methods to immobilize ligand(s). Furthermore, we review research articles that deal with microfluidic devices as analytical tools for biomolecule (DNA, RNA and protein) separation. 相似文献
4.
Affinity chromatography on monolithic supports is a powerful analytical chemical platform because it allows for fast analyses, small sample volumes, strong enrichment of trace biomarkers and applications in microchips. In this review, the recent research using monolithic materials in the field of bioaffinity chromatography (including immunochromatography) is summarized and discussed. After giving an introduction into affinity chromatography, information on different biomolecules (antibodies, enzymes, lectins, aptamers) that can act as ligands in bioaffinity chromatography is presented. Subsequently, the history of monoliths, their advantages, preparation and formats (disks, capillaries and microchips) as well as ligand immobilization techniques are mentioned. Finally, analytical and preparative applications of bioaffinity chromatography on monoliths are presented. During the last four years 37 papers appeared. Protein A and G are still most often used as ligands for the enrichment of immunoglobulins. Antibodies and lectins remain popular for the analysis of mainly smaller molecules and saccharides, respectively. The highly porous cryogels modified with ligands are applied for the sorting of different cells or bacteria. New is the application of aptamers and phages as ligands on monoliths. Convective interaction media (epoxy CIM disks) are currently the most used format in monolithic bioaffinity chromatography. 相似文献
5.
Rare earth element substituted bismuth ferrites (BiFeO3) are of enormous importance as magnetoelectric materials. The polycrystalline samples of Bi
x
La1−x
FeO3 (x=0, 0.2, 0.4, 0.6, 0.8) were prepared by solid-state reaction using standard ceramic method. The single-phase formation of
these compounds was confirmed by X-ray diffraction (XRD) studies. The samples with x=0, 0.2, 0.4, 0.6 are found to be orthorhombic while the sample with x=0.8 is triclinic. The dielectric constant (ε′) and dissipation factor (tan δ) were measured in the frequency range 100 Hz
to 1 MHz at room temperature and as a function of temperature at certain fixed frequencies (1 kHz, 10 kHz, 100 kHz, 1 MHz).
All the samples showed dielectric dispersion. The dielectric constant with temperature shows a broad peak; the peak temperature
shifts with frequency which reflects the relaxor-type behavior. The peak above 600 K in the measured temperature range corresponds
to antiferromagnetic ordering temperature (Néel temperature). The broadness of the peak changes with composition. The ac conductivity
as well as ε′ are found to be maximum for the sample x=0.2 at room temperature. 相似文献
6.
CoFe2O4-BaTiO3 composites were prepared using conventional ceramic double sintering process with various compositions. Presence of two phases
in the composites was confirmed using X-ray diffraction. The dc resistivity and thermoemf as a function of temperature in
the temperature range 300 K to 600 K were measured. Variation of dielectric constant (ɛ′) with frequency in the range 100 Hz to 1 MHz and also with temperature at a fixed frequency of 1 kHz was studied. The ac
conductivity was derived from dielectric constant (ɛ′) and loss tangent (tan δ). The nature of conduction is discussed on the basis of small polaron hopping model. The static value of magnetoelectric
conversion factor has been studied as a function of magnetic field. 相似文献
7.
David L Kirkham Laura KK Pacey Michelle M Axford Roberta Siu Daniela Rotin Laurie C Doering 《BMC neuroscience》2006,7(1):50-9
Background
The LAR family Protein Tyrosine Phosphatase sigma (PTPσ) has been implicated in neuroendocrine and neuronal development, and shows strong expression in specific regions within the CNS, including the subventricular zone (SVZ). We established neural stem cell cultures, grown as neurospheres, from the SVZ of PTPσ knockout mice and sibling controls to determine if PTPσ influences the generation and the phenotype of the neuronal, astrocyte and oligodendrocyte cell lineages. 相似文献8.
Fabrication of polystyrene hollow microspheres as laser fusion targets by optimized density-matched emulsion technique and characterization 总被引:3,自引:0,他引:3
Inertial confinement fusion, frequently referred to as ICF, inertial fusion, or laser fusion, is a means of producing energy
by imploding small hollow microspheres containing thermonuclear fusion fuel. Polymer microspheres, which are used as fuel
containers, can be produced by solution-based micro-encapsulation technique better known as density-matched emulsion technique. The specifications of these microspheres are very rigorous, and various aspects of the emulsion hydrodynamics associated
with their production are important in controlling the final product. This paper describes about the optimization of various
parameters associated with density-matched emulsion method in order to improve the surface smoothness, wall thickness uniformity
and sphericity of hollow polymer microspheres. These polymer microshells have been successfully fabricated in our lab, with
3–30 μm wall thickness and 50–1600 μm diameters. The sphericity and wall thickness uniformity are better than 99%. Elimination
of vacuoles and high yield rate has been achieved by adopting the step-wise heating of W1/O/W2 emulsion for solvent removal. 相似文献
9.
Single step synthesis of carbohydrate monolithic capillary columns for affinity chromatography of lectins 总被引:1,自引:0,他引:1
Carbohydrate monolithic beds were synthesized in a single step in capillary columns to study affinity chromatography of lectins. In this method, carbohydrates (beta-galactose, beta-glucose, and alpha-mannose) with an easy to synthesize alkene terminated tetraethylene glycol spacer were used as functional monomers along the monomer 2-hydroxyethyl methacrylate (HEMA). As crosslinkers (+)-N,N'-diallyltartardiamide (DATD) and piperazine diacrylamide (PDA, 1,4-bisacryloyl-piperazine) were used. SEM showed the successful formation of monolithic beds in the capillary columns. The permeability of the columns was high. The specific interaction of the lectins Con A, Lens culinaris (LCA) and Arachis hypogaea (PNA) with the carbohydrate stationary phase was studied by frontal affinity chromatography (FAC). Con A and LCA were successfully eluted from the column using 0.1 M methyl-alpha-mannopyranoside and PNA with 0.1 M beta-galactose. Dissociation constants (Kd) for carbohydrate-lectin interactions were determined and compared with literature. 相似文献
10.
Ashish Khaparde S. Lokesh Kumar M. A. Vijayalakshmi Kishore K. R. Tetala 《Electrophoresis》2021,42(24):2647-2655
PDMS-based multichannel microfluidic chip was designed and fabricated in a simple approach using readily available tools. UV-initiated in situ polymerization of poly(2-hydroxy ethyl methacrylate-co-di(ethylene glycol) diacrylate-co-N,Nʹ-diallyl l -tartardiamide) in an Eppendorf tube was achieved within 40 min. This polymerization process was successfully translated to a microfluidic chip format without any further modifications. Iminodiacetic acid was successfully immobilized on aldehyde functional monoliths via Schiff base reaction and confirmed by FT-IR spectroscopy. Four transition metal ions (Co (II), Zn (II), Ni (II), and Cu (II)) were chelated individually on four IDA-monolith microfluidic chips. The conjoint metal-ion monolith microfluidic chip has displayed high permeability (9.40 × 10–13 m2) and a porosity of 32.8%. This affinity microfluidic chip has pre-fractioned four human plasma proteins (fibrinogen, immunoglobulin, transferrin, and human serum albumin) based on their surface-exposed histidine surface topography. A protein recovery of approximately 95% (Bradford assay data) was achieved. The multimonolith microchip can be reusable even after three protein adsorption-desorption cycles. 相似文献
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