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91.
Capillary liquid chromatography of multiple peptides with on-line capillary electrophoresis immunoassay detection. 总被引:2,自引:0,他引:2
A competitive immunoassay for neuropeptide Y (NPY) based on capillary electrophoresis (CE) with laser-induced fluorescence detection was developed utilizing polyclonal antisera as the immunoreagent and fluorescein-labeled NPY as the tracer. The assay was performed with on-line mixing of reagents, automated injections, and a 3 s separation time. The assay had a detection limit of 850 pM. To detect NPY at lower concentrations, the assay was coupled on-line to reversed-phase capillary liquid chromatography (LC). In this arrangement, 5 microL samples were preconcentrated by capillary LC and eluted by a gradient of isopropanol-containing mobile phase. The resulting chromatographic peaks were monitored by the CE immunoassay. With preconcentration, the concentration detection limit was improved to 40 microM and NPY could be measured in push-pull perfusion samples collected from the paraventricular nucleus of freely moving rats. The technique was extended to simultaneous detection of NPY and glucagon secretion from islets of Langerhans. 相似文献
92.
Kelsey L. Horvath Dr. Christopher G. Newton Dr. Kimberley A. Roper Dr. Jas S. Ward Prof. Michael S. Sherburn 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4072-4076
The first general synthesis of compounds of the tetravinylethylene (TVE) family is reported. Ramirez-type dibromo-olefination of readily accessible penta-1,4-dien-3-ones generates 3,3-dibromo[3]dendralenes, which undergo twofold Negishi, Suzuki–Miyaura or Mizoroki–Heck reactions with a wide variety of olefinic coupling partners. This route delivers a broad range of unsymmetrically substituted tetravinylethylenes with up to three different alkenyl substituents attached to the central C=C bond. The extensive scope of the approach is demonstrated by the preparation of the first higher order oligo-alkenic through-conjugated/cross-conjugated hybrid compounds. An unsymmetrically substituted TVE is shown to undergo a domino electrocyclization–cycloaddition with high site-selectivity and diastereoselectivity, thereby demonstrating the substantial synthetic potential of substituted TVEs for controlled, rapid structural complexity generation. 相似文献
93.
A mathematical model describing the coupling of electrical,optical and thermal effects in semiconductor lasers is introduced.Numerical and asymptotic solutions are derived, including expressionsfor key physical quantities such as the initial time delay,the frequency of spike oscillation and the temperature rise,together with its influence on the photon density, the electronconcentration and the threshold current. The consequences ofthermal effects in reducing efficiency are thus quantified. 相似文献
94.
Clifton E. F. Rickard Warren R. Roper Alex Williamson L. James Wright 《Angewandte Chemie (International ed. in English)》1999,38(8):1110-1113
Support for key steps of the mechanism for the transition metal catalyzed hydroboration reaction is provided by the characterization and reactions of 1 , a cis-(boryl)(aryl) complex of osmium(II ). This compound readily eliminates o-tolylBcat to give the osmium(0) intermediate 2 , which in the presence of HBcat reestablishes the osmium–boron bond by forming 3 . R=o-tolyl, H2cat=catechol=1,2-(HO)2C6H4. 相似文献
95.
A visit by one of the authors to Estonia, and the discovery that the term ‘red’ was used locally for the colour ‘orange’, led to a detailed study of the colour red in Estonian belief and culture. The study is reported here, together with an interpretation of the red/orange substitution based on Berlin and Kay's model of colour term development in language. 相似文献
96.
Dr. Robert E. Ziegler Dr. Bimbisar K. Desai Dr. Jo‐Ann Jee Prof. Dr. B. Frank Gupton Prof. Dr. Thomas D. Roper Prof. Dr. Timothy F. Jamison 《Angewandte Chemie (International ed. in English)》2018,57(24):7181-7185
Dolutegravir (DTG), an important active pharmaceutical ingredient (API) used in combination therapy for the treatment of HIV, has been synthesized in continuous flow. By adapting the reported GlaxoSmithKline process chemistry batch route for Cabotegravir, DTG was produced in 4.5 h in sequential flow operations from commercially available materials. Key features of the synthesis include rapid manufacturing time for pyridone formation, one‐step direct amidation of a functionalized pyridone, and telescoping of multiple steps to avoid isolation of intermediates and enable for greater throughput. 相似文献
97.
A multianalyte CE competitive immunoassay using two-color detection was developed to measure insulin and glucagon in islets of Langerhans. Insulin was quantified with FITC-insulin (Ins*) and anti-insulin antibodies (Ins Ab) and glucagon was quantified with Cy5-glucagon (Glu*) and anti-glucagon antibodies (Glu Ab). A 3 mW Ar(+) laser at 488 nm and a 25 mW laser diode at 635 nm were used to excite FITC and Cy5, respectively. Fluorescence was split with a half-silvered mirror and passed through a 520 +/- 20 nm bandpass filter or a 663 nm longpass filter for the detection of insulin and glucagon, respectively. The two-color detection format enabled independent quantitation of both analytes even with concentrations of insulin immunoassay reagents 20-fold higher than glucagon reagents. Simultaneous calibration curves were generated and used to determine insulin and glucagon content in islets of Langerhans. Amounts of insulin and glucagon were 56.6 +/- 3.2 and 1.0 +/- 0.5 ng/islet, respectively. LODs were 7 nM insulin and 3 nM glucagon. The assay will be applicable to fast monitoring of multiple peptides secreted from islets of Langerhans and can be applied to other systems for the quantitation of multiple analytes with large differences in concentrations. 相似文献
98.
Tierno P Reddy SV Roper MG Johansen TH Fischer TM 《The journal of physical chemistry. B》2008,112(12):3833-3837
Paramagnetic particles in a magnetic ratchet potential were transported in discrete steps in an aqueous solution on the surface of a magnetic garnet film. The proposed technique allows the simultaneously controlled, dispersion-free movement of an ensemble of paramagnetic particles across the surface. External magnetic modulations were used to transport the particles in a defined direction, and a current reversal upon changing the size of the particles was used to separate particles having different diameters. Doublets consisting of a larger and a smaller particle functionalized with complimentary oligonucleotides and bound via Watson-Crick base pairing were separated after melting the double stranded DNA. 相似文献
99.
100.
Jonathan P. Williams Andrew J. Creese David R. Roper Brian N. Green Helen J. Cooper 《Journal of the American Society for Mass Spectrometry》2009,20(9):1707-1713
Population migration has led to the global dispersion of human hemoglobinopathies and has precipitated a need for their identification.
An effective mass spectrometry-based procedure involves analysis of the intact α- and β-globin chains to determine their mass, followed by location of the variant amino acid residue by direct analysis of the enzymatically
digested chains and low-energy collision induced dissociation of the variant peptide. Using this procedure, a variant was
identified as either β54Val→Leu or β54Val→Ile, since the amino acids leucine and isoleucine cannot be distinguished using low-energy collisions. Here, we describe
how hot electron capture dissociation on a Fourier transform-ion cyclotron resonance mass spectrometer was used to distinguish
isoleucine from leucine and identify the mutation as β54(D5)Val→Ile. This is a novel variant, and we have named it Hb Askew. 相似文献