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111.
Bolton PD Clot E Cowley AR Mountford P 《Chemical communications (Cambridge, England)》2005,(26):3313-3315
The imidotitanium alkyl cations [Ti(NtBu)(Me3[9]aneN3)R]+ (R = Me (3+) or CH2SiMe3(4+)) possess either a very weak alpha-agostic or beta-Si-C agostic interactions, respectively, according to 13C and 29Si NMR and DFT studies; reaction of (4+) with iPrNCNiPr gives totally selective insertion into the Ti-alkyl bond; reaction of 3+ with AlMe3 gives the first structurally characterised AlMe3 adduct of a transition metal alkyl cation (Me3[9]aneN3 = 1,4,7-trimethyltriazacyclononane). 相似文献
112.
Capps KL McLaughlin EM Murray AW Aldus CF Wyatt GM Peck MW van Amerongen A Ariëns RM Wichers JH Baylis CL Wareing DR Bolton FJ 《Journal of AOAC International》2004,87(1):68-77
An interlaboratory study was conducted for the validation of 3 methods for the detection of all verotoxin-producing Escherichia coli (VTEC) in foods. The methods were a multi-analyte 1-step lateral flow immunoassay (LFIA) for detection of E. coli O157 and verotoxin (VT); an enzyme-linked immunosorbent assay targeted against VT1, VT2, and VT2c (VT-ELISA); and a polymerase chain reaction (PCR) method for detection of VT genes (VT-PCR). Aliquots (25 g or 25 mL) of 4 food types (raw minced [ground] beef, unpasteurized milk, unpasteurized apple juice [cider], and salami) were individually inoculated with low numbers (<9 to 375 cells/25 g) of 6 test strains of E. coli (serogroups O26, O103, O111, O145, and O157) with differing VT-producing capabilities. Five replicates for each test strain and 5 uninoculated samples were prepared for each food type. Fourteen participating laboratories analyzed samples using the LFIA, 9 analyzed the samples by ELISA, and 9 by PCR. The LFIA for O157 and VT had a specificity (correct identification of negative samples) of 92 and 94%, respectively, and a sensitivity (correct identification of positive samples) of 94 and 55%, respectively. The VT-ELISA and VT-PCR had a specificity of 98 and 99%, respectively, and a sensitivity of 89 and 72%, respectively. 相似文献
113.
Daniel H. Bolton Karen L. Wooley 《Journal of polymer science. Part A, Polymer chemistry》2002,40(7):823-835
Hyperbranched aryl polycarbonates were prepared via the polymerizations of A2B and AB2 monomers, which involved the condensation of chloroformate (A) functionalities with tert‐butyldimethylsilyl‐protected phenols (B), facilitated by reactions with silver fluoride. The polymerization of the A2B monomer gave hyperbranched polycarbonates bearing fluoroformate chain ends, which were hydrolyzed to phenolic chain‐end moieties and further elaborated to tert‐butyldimethylsilyl ether groups. The polymerization of the AB2 monomer gave tert‐butyldimethylsilyl ether‐terminated hyperbranched polycarbonates. The polymerizations were conducted at 23–70 °C in 20% acetonitrile/tetrahydrofuran in the presence of a stoichiometric excess of silver fluoride for 20–40 h to afford hyperbranched polycarbonates with weight‐average molecular weights exceeding 100,000 Da and polydispersity indices of typically 2–3. The degrees of branching were determined by a reductive degradation procedure followed by high‐performance liquid chromatography. Alternatively, the degrees of branching were measurable by solution‐state 1H NMR analyses and agreed with the statistical 50% branching expected for the polymerization of A2B and AB2 monomers not experiencing constructive or destructive electronic effects on the reactivity of the multiple functional groups. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 823–835, 2002; DOI 10.1002/pola.10167 相似文献
114.
Abstract— The effect of photocrosslinking s 4 U 8 with C 13 on the structure of E. coli tRNA has been examined by high resolution NMR. Photocrosslinking affects both the structure and the enzymatic acylation of tRNA. The NMR measurements demonstrate that except for the s 4 U 8 .A14 base pair, there is no evidence that photocrosslinking perturbs any of the common tertiary structure interactions. However, this modification does perturb several resonances which are assigned to the secondary structure base pairs of the hU stem and the terminal base pair of the acceptor stem. The variable effect of photocrosslinking on the extent and rate of enzymatic acylation of different tRNA is attributed to different recognition sites for tRNA by the cognate synthetases. 相似文献
115.
The fragmentation of simple alkyl acridines closely resembles that of the analogous quinoline derivatives. Interaction between the heteroatom and a 4-alkyl substituent dramatically influences the fragmentation pattern with resultant γ-cleavage or rearrangement to the heteroatom and corresponding elimination of an alkene fragment. The fragmentation of the 9-chloroalkylacridines closely resembles that of the acridines with the loss of the clorine atom superposed on the alkylacridine fragmentation. Redistribution of the centre of apparent charge localization occurs for the acridones with a tendency for interaction with the 9-position. 相似文献
116.
Bolton RD Bowman JD Cooper MD Frank JS Hallin AL Heusi PA Hoffman CM Hogan GE Mariam FG Matis HS Mischke RE Nagle DE Piilonen LE Sandberg VD Sanders GH Sennhauser U Werbeck R Williams RA Wilson SL Hofstadter R Hughes EB Ritter MW Grosnick D Wright SC Highland VL McDonough J 《Physical review letters》1986,56(23):2461-2464
117.
Adler J Becker JJ Blaylock GT Bolton T Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Dorfan DE Dubois GP Duncan AL Eigen G Einsweiler KF Eisenstein BI Freese T Gladding G Grab C Grancagnolo F Hamilton RP Hauser J Heusch CA Hitlin DG Izen JM Köpke L Li A Lockman WS Mallik U Matthews CG Mir R Mockett PM Mozley RF Nemati B Odian A Parrish L Partridge R Perrier J Pitman D Plaetzer SA Richman JD Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Simopoulos C 《Physical review letters》1987,59(14):1527-1529
118.
Adler J Becker JJ Blaylock GT Bolton T Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Dorfan DE Dubois GP Duncan AL Eigen G Einsweiler KF Eisenstein BI Freese T Gladding G Grab C Grancagnolo F Hamilton RP Hauser J Heusch CA Hitlin DG Izen JM Köpke L Li A Lockman WS Mallik U Matthews CG Mir R Mockett PM Mozley RF Nemati B Odian A Parrish L Partridge R Perrier J Pitman D Plaetzer SA Richman JD Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Simopoulos C 《Physical review letters》1988,60(14):1375-1378
119.
120.
Adler J Bai Z Blaylock GT Bolton T Brient J Browder TE Brown JS Bunnell KO Burchell M Burnett TH Cassell RE Coffman D Cook V Coward DH DeJongh F Dorfan DE Drinkard J Dubois GP Eigen G Einsweiler KF Eisenstein BI Freese T Gatto C Gladding G Grab C Hauser J Heusch CA Hitlin DG Izen JM Kim PC Köpke L Labs J Li A Lockman WS Mallik U Matthews CG Mincer AI Mir R Mockett PM Nemati B Odian A Parrish L Partridge R Pitman D Plaetzer SA Richman JD Sadrozinski HF Scarlatella M Schalk TL Schindler RH 《Physical review letters》1990,64(22):2615-2618