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51.
The histamine level in tomato fruits and pastes was determined by 2 orthogonal techniques as a means of comparing accuracy. Close statistical agreement was found between assays for free histamine by capillary electrophoresis (with UV absorbance detection), and for the dansyl derivative by reversed-phase liquid chromatography (LC). Both techniques have adequate sensitivity for the analysis of endogenous histamine in tomatoes, but LC/electrospray tandem mass spectrometry was more sensitive by at least an order of magnitude, down to a level of 0.05 mg/kg. 相似文献
52.
Nicole L. K. Thiher Sage M. Schissel Julie L. P. Jessop 《Journal of polymer science. Part A, Polymer chemistry》2020,58(7):1011-1021
The vast majority of industrial electron-beam (EB) polymerizations are initiated via radical mechanism. Because radicals drive EB polymerization, understanding their formation and secondary reactions can provide insight into polymerization kinetics and property development. Primary and initiating radicals were quantified by measuring G(R•) and G(M•) , respectively, for various acrylate and methacrylate monomers. Monomer chemistry was shown to impact primary radical formation; however, increased primary radical concentration did not necessarily correlate to increased conversion. Despite exhibiting high values of G(R•) , methacrylates achieved very little conversion and had G(M•) values near zero. Acrylates achieved much higher G(M•) values and rates of polymerization compared to their methacrylate counterparts. Additionally, the efficiency of primary radicals converting to initiating radicals, f(M•) , for each acrylate monomer was shown to be a good predictor of the amount of gel fraction formed during polymerization. Understanding radical formation and secondary radical reactions can help guide the structure/processing conditions/properties relationships that are currently underdeveloped for EB reactions. 相似文献
53.
Formanilide and carbanilide from aniline and carbon dioxide 总被引:1,自引:0,他引:1
Pradip MunshiDavid J. Heldebrant Erin P. McKoonPatrick A. Kelly Chih-Cheng TaiPhilip G. Jessop 《Tetrahedron letters》2003,44(13):2725-2727
Earlier syntheses of formamides from the catalytic hydrogenation of CO2 in the presence of amines were only successful for the preparation of dialkylformamides. After an analysis of the reason for the failure of the reaction using aniline as a starting material, formanilide has been prepared, for the first time, from CO2, H2 and aniline with the use of 1,8-diazabicyclo[5.4.0]undec-7-ene. Omission of the H2 reductant causes the selectivity to switch to the production of carbanilide (1,3-diphenylurea). 相似文献
54.
Liquid poly(ethylene glycol) and supercritical carbon dioxide: a benign biphasic solvent system for use and recycling of homogeneous catalysts 总被引:1,自引:0,他引:1
Poly(ethylene glycol) (PEG), having a molecular weight of 900 or 1500, is a solid at room temperature but a nonvolatile liquid at 40 degrees C under CO2 pressure. Homogeneously catalyzed hydrogenation can be performed in the molten PEG, followed by extraction of the product by supercritical CO2. The catalyst-containing PEG phase which remains in the vessel can be reused for hydrogenation without addition of further catalyst or PEG. 相似文献
55.
Jessop PG Olmstead MM Ablan CD Grabenauer M Sheppard D Eckert CA Liotta CL 《Inorganic chemistry》2002,41(13):3463-3468
Highly fluorinated organic or organometallic solid compounds can be made to dissolve in liquid hydrocarbons by the application of 20-70 bar of CO(2) gas. Subsequently releasing the gas causes the compounds to precipitate or crystallize, giving quantitative recovery of the solid. The resulting crystals can be of sufficient quality for single-crystal X-ray crystallography; the structures of Rh(2)(O(2)CCF(2)CF(2)CF(3))(4)(DMF)(2), Rh(2)(O(2)C(CF(2))(9)F)(4)(MeOH)(2), Cr(hfacac)(3), and P[C(6)H(3)(3,5-CF(3))(2)](3) have been determined from crystals grown in this manner. 相似文献
56.
Bolygo E Ricketts D Moffatt F Jessop M Attenborough S 《Analytical and bioanalytical chemistry》2003,376(5):701-705
A liquid chromatography method was developed for the determination of antifungal/antimicrobial proteins Rs-AFP1 and Dm-AMP1 in sandy loam soils. The extraction of these highly basic proteins was achieved by mechanical shaking with aqueous Tris buffer pH 9 containing guanidinium thiocyanate salt (4.1 M), EDTA and nonionic polyoxyethylene 20 cetyl ether, Brij-58 detergent. The extracts were cleaned up on Oasis HLB polymer solid-phase extraction cartridges and quantified by liquid chromatography fluorescence detection based on the fluorescence properties of the tryptophan content of these proteins. The detector response was linear for 0.3-10 microg mL(-1). Procedural recoveries were tested in the range 10-100 mg kg(-1). The limit of quantification was 10 mg kg(-1 )protein in the soil sample representing the lowest validated fortification level. The antifungal proteins were found to be stable in soil extract tested up to 9 days when stored at 4 degrees C. 相似文献
57.
Duboscq JE Fulton R Fujino D Gan KK Honscheid K Kagan H Kass R Lee J Sung M White C Wanke R Wolf A Zoeller MM Fu X Nemati B Richichi SJ Ross WR Skubic P Wood M Bishai M Fast J Gerndt E Hinson JW Miao T Miller DH Modesitt M Shibata EI Shipsey IP Wang PN Gibbons L Johnson SD Kwon Y Roberts S Thorndike EH Jessop CP Lingel K Marsiske H Perl ML Schaffner SF Wang R Coan TE Dominick J Fadeyev V Korolkov I Lambrecht M Sanghera S Shelkov V Stroynowski R Volobouev I Wei G Artuso M Efimov A Gao M 《Physical review letters》1996,76(21):3898-3902
58.
Alam MS Kim IJ Ling Z Mahmood AH O'Neill JJ Severini H Sun CR Timm S Wappler F Duboscq JE Fulton R Fujino D Gan KK Honscheid K Kagan H Kass R Lee J Sung M White C Wanke R Wolf A Zoeller MM Fu X Nemati B Richichi SJ Ross WR Skubic P Wood M Bishai M Fast J Gerndt E Hinson JW Miao T Miller DH Modesitt M Shibata EI Shipsey IP Wang PN Gibbons L Johnson SD Kwon Y Roberts S Thorndike EH Jessop CP Lingel K Marsiske H Perl ML Schaffner SF Wang R Coan TE Dominick J Fadeyev V Korolkov I Lambrecht M 《Physical review letters》1996,76(15):2637-2641
59.
Anderson S Frolov VV Kubota Y Lee SJ Mahapatra R O'Neill JJ Poling R Riehle T Smith A Stepaniak CJ Urheim J Ahmed S Alam MS Athar SB Jian L Ling L Saleem M Timm S Wappler F Anastassov A Duboscq JE Eckhart E Gan KK Gwon C Hart T Honscheid K Hufnagel D Kagan H Kass R Pedlar TK Schwarthoff H Thayer JB von Toerne E Zoeller MM Richichi SJ Severini H Skubic P Undrus A Chen S Fast J Hinson JW Lee J Miller DH Shibata EI Shipsey IP Pavlunin V Cronin-Hennessy D Lyon AL Thorndike EH Jessop CP Marsiske H 《Physical review letters》2001,86(13):2732-2736
We report the first observation of exclusive decays of the type B-->D(*)N_NX, where N is a nucleon. Using a sample of 9.7x10(6)B_B pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B0-->D(*-)p_p pi(+)) = (6.5(+1.3)(-1.2)+/-1.0)x10(-4) and B(B0-->D(*-)p_n) = (14.5(+3.4)(-3.0)+/-2.7)x10(-4). Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter. 相似文献
60.
Jessop CP Marsiske H Perl ML Savinov V Ugolini D Zhou X Coan TE Fadeyev V Maravin Y Narsky I Stroynowski R Ye J Wlodek T Artuso M Ayad R Boulahouache C Bukin K Dambasuren E Karamov S Majumder G Moneti GC Mountain R Schuh S Skwarnicki T Stone S Viehhauser G Wang JC Wolf A Wu J Kopp S Csorna SE Danko I McLean KW Márka S Xu Z Godang R Kinoshita K Lai IC Schrenk S Bonvicini G Cinabro D McGee S Perera LP Zhou GJ Lipeles E Schmidtler M Shapiro A Sun WM Weinstein AJ Würthwein F Jaffe DE Masek G 《Physical review letters》2000,85(14):2881-2885
We report results of searches for charmless hadronic B meson decays to pseudoscalar( pi(+/-), K+/-, pi(0), or K(0)(S))-vector( rho, K(*), or omega) final states. By using 9.7x10(6) BB pairs collected with the CLEO detector, we report the first observation of B(-)--->pi(-)rho(0), B(0)-->pi(+/-)rho(-/+), and B(-)-->pi(-)omega, which are expected to be dominated by hadronic b-->u transitions. The measured branching fractions are (10.4(+3.3)(-3.4)+/-2.1)x10(-6), (27.6(+8.4)(-7.4)+/-4.2)x10(-6), and (11.3(+3.3)(-2.9)+/-1. 4)x10(-6), respectively. Branching fraction upper limits are set for all of the other decay modes investigated. 相似文献