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排序方式: 共有393条查询结果,搜索用时 46 毫秒
131.
Miller DH Sanghi B Shipsey IP Xin B Adams GS Anderson M Cummings JP Danko I Ge JY Hu D Moziak B Napolitano J He Q Insler J Muramatsu H Park CS Thorndike EH Yang F Artuso M Blusk S Khalil S Li J Menaa N Mountain R Nisar S Randrianarivony K Sia R Skwarnicki T Stone S Wang JC Bonvicini G Cinabro D Dubrovin M Lincoln A Asner DM Edwards KW Naik P Briere RA Ferguson T Tatishvili G Vogel H Watkins ME Rosner JL Adam NE Alexander JP Cassel DG Duboscq JE Ehrlich R Fields L Gibbons L Gray R Gray SW 《Physical review letters》2007,99(12):122002
We measure the mass of the eta meson using psi(2S) --> etaJ/psi events acquired with the CLEO-c detector operating at the CESR e(+)e(-) collider. Using the four decay modes eta --> gamma gamma, 3pi(0), pi(+)pi(-)pi(0), and pi(+)pi(-)gamma, we find M(eta) = 547.785 +/- 0.017 +/- 0.057 MeV, in which the first uncertainty is statistical and the second systematic. This result has an uncertainty comparable to the two most precise previous measurements and is consistent with that of NA48, but is inconsistent at the level of 6.5 sigma with the much smaller mass obtained by GEM. 相似文献
132.
The performance of sera pre-treatment for biomarker searching via combinatorial peptide ligand libraries (CPLL) has recently been challenged (Proteomics 2010, 10, 1416-1425) and stated to allow discovery of only medium to high-abundance proteins. We have thus investigated four elution protocols, as published in recent reports: (i) in 4?M urea+1% CHAPS; (ii) in 4?M urea+1% CHAPS+5% acetic acid; (iii) in 8?M urea+2% CHAPS+5% acetic acid; (iv) in boiling 4% SDS+25?mM DTT. One milliliter of serum, in all cases, was captured with 50?μL of CPLL beads, which were then eluted with the four eluants described above. In the first three cases, after the first elution, the beads were re-eluted with cocktail (iv), known to offer maximal release of proteins adsorbed by the CPLL ligands. Eluant (i) released only ca. 20% of the species adsorbed, eluant (ii) ca. 60%, eluant (iii) ca. 80%. Thus, the poor performance of the CPLL methodology, as reported in (i) is not due to any fault of the capture technique, but simply to the adoption of a very poor elution protocol. Even those using eluants (ii) and (iii) should know that a substantial fraction of the captured species still remains bound to the beads and is thus not available to biomarker discovery. Once more, eluant (iv) is recognized as the only one able to offer optimal recovery from the CPLL baits. 相似文献
133.
A highly stereoselective BF(3)·OEt(2)-promoted tandem hydroamination-glycosylation on a glycal scaffold has been developed to form 3-amino-2,3-dideoxysugars in a one-pot procedure. This efficient multicomponent reaction protocol offers simplicity and general applicability to a broad range of variations on each component. 相似文献
134.
Cai S Xiang S Zeng J Gorityala BK Liu XW 《Chemical communications (Cambridge, England)》2011,47(30):8676-8678
Carbohydrate-integrated isoxazolines were synthesized from 2-nitroglycals and sulfur ylides, with the aid of 1-phenylthiourea catalyst. The reactions proceeded via [4+1] annulations and upon subsequent rearrangement, afforded the corresponding isoxazolines in high yields with excellent diastereoselectivities (up to 95% de). 相似文献
135.
Vishal Kumar Baderia V. Sorna Gowri Sunil Kumar Sanghi Ankita Shukla Deepesh Kumar Singh Shail Bala Sanghi 《Journal of Analytical Chemistry》2012,67(3):278-283
In aqueous capillary electrophoresis, the electroosmotic flow can be strongly suppressed by coating the inner surface of the
capillary. In the present work hydrophilic coating of 4% polyvinyl alcohol (PVA) has been used for the analysis of basic proteins. The coating is simple and easy to obtain. The separation of ribonuclease
and α-chymotrypsin has been uniquely done with other three basic proteins (lysozyme, cytochrome-c and trypsin) using a buffer
11.60 mM sodium acetate and 18.40 mM acetic acid at pH 4.5 in addition to positive power supply of 20 kV at 25°C. Detection
was performed using UV detector at 230 nm. The proposed PVA coated capillary provides reproducible separation of five basic
proteins within 10 min with RSD values for mobility bellow 1.4% (n = 6) for all the five basic proteins. The stability of coated capillary has been checked up to 40 runs. The viscosity measurement
for 4% PVA have been studied and scanning electron microscope (SEM) images obtained to make it compatible with future micro-chip applications. 相似文献
136.
A new, simple and effective amperometric acetylcholinesterase biosensor was developed using screen-printed carbon electrodes modified with carbon nanotubes (MWCNTs)–7,7,8,8-tetracyanoquinodimethane (TCNQ). The design of the biosensor was based on the supramolecular arrangement resulted from the interaction of MWCNTs and TCNQ. This arrangement was confirmed by spectroscopic and electrochemical techniques. Two different supramolecular arrangements were proposed based on different MWCNTs:TCNQ ratios. The synergistic effect of MWCNTs and TCNQ was, for the first time, exploited for detection of thiocholine at low potential with high sensitivity. The biosensor developed by immobilization of acetylcholinesterase (AChE) in sol–gel allowed the detection of two reference AChE inhibitors, paraoxon-methyl and chlorpyrifos with detection limits of 30 pM (7 ppt) and 0.4 nM (0.1 ppb), respectively. Efficient enzyme reactivation was obtained by using obidoxime. 相似文献
137.
Stephen Michael RajeshBalasubramainan Devi Bala Subbu Perumal 《Tetrahedron letters》2012,53(40):5367-5371
A library of novel 1-methyl-4-arylpyrrolo-(spiro[2.2′]indan-1′,3′-dione)-spiro[3.3″]-1″-methyl/benzyl-5″-(arylmethylidene)piperidin-4″-ones and 1-methyl-4-arylpyrrolo-(spiro[2.11′]-11H-indeno[1,2-b]quinoxaline)-spiro[3.3″]-1″-methyl/benzyl-5″-(arylmethylidene)piperidin-4″-ones have been synthesized via 1,3-dipolar azomethine ylide cycloaddition in the ionic liquid, 1-butyl-3-methylimidazolium bromide ([BMIm]Br), in excellent yields. 相似文献
138.
Navneet Singh Ashish Agarwal Sujata Sanghi Satish Khasa 《Journal of magnetism and magnetic materials》2012
The dielectric properties, dc and ac electrical resistivities of Mg substituted Ni–Cu ferrites with general formula Ni0.5Cu0.5−xMgxFe2O4 (0.0≤x≤0.5) have been investigated as a function of frequency, temperature and composition. ac resistivity of all the samples decreases with increase in the frequency exhibiting normal ferrimagnetic behavior. The frequency dependence of dielectric loss tangent showed a maximum in between 10 Hz and 1 kHz in all the ferrites. The conductivity relaxation of the charge carriers was examined using the electrical modulus formulism, and the results indicate the presence of the non-Debye type of relaxation in the prepared ferrites. Similar values of activation energies for dc conduction and for conductivity relaxation reveal that the mechanism of electrical conduction and dielectric polarization is the same in these ferrites. A single ‘master curve’ for normalized plots of all the modulus isotherms observed for a given composition indicates that the distribution of relaxation time is temperature independent. The saturation magnetization and coercivity as calculated from the hysteresis loop measurement show striking dependence on composition. 相似文献
139.
140.
Abelev B Abrahantes Quintana A Adamová D Adare AM Aggarwal MM Aglieri Rinella G Agocs AG Agostinelli A Aguilar Salazar S Ahammed Z Ahmad N Ahmad Masoodi A Ahn SU Akindinov A Aleksandrov D Alessandro B AlfaroMolina R Alici A Alkin A Almaráz Aviña E Alt T Altini V Altinpinar S Altsybeev I Andrei C Andronic A Anguelov V Anson C Antičić T Antinori F Antonioli P Aphecetche L Appelshäuser H Arbor N Arcelli S Arend A Armesto N Arnaldi R Aronsson T Arsene IC Arslandok M Asryan A Augustinus A Averbeck R 《Physical review letters》2012,108(8):082001
The ALICE Collaboration has studied J/ψ production in pp collisions at √s=7 TeV at the LHC through its muon pair decay. The polar and azimuthal angle distributions of the decay muons were measured, and results on the J/ψ polarization parameters λ(θ) and λ(φ) were obtained. The study was performed in the kinematic region 2.5相似文献