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51.
The temperature dependence of the homogeneous linewidth (Γhom) of S1 ← S0 0-0 transitions of organic amorphous systems undergoing either photochemical or non-photochemical hole-burning from 4.2 down to 0.3 K is presented. In all cases Γhom follows a T1.3 dependence, and extrapolates to or actually reaches the lifetime-limited value of the guest. An estimate of the relative guest-host coupling strengths is made. 相似文献
52.
A.I.M. Dicker M. Noort H.P.H. Thijssen S. Völker J.H. Van Der Waals 《Chemical physics letters》1981,78(2):212-218
Zeeman experiments are reported on the S1 ← S0 O-O transitions of chlorin (7,8-dihydroporphin) and its photoisomer in an n-hexane crystal by photochemical hole burning at 4.2 K. The holes shift with a quadratic field dependence of -39.0 MHz/T2 (chlorin) and ?245.3 MHz/T2 (photoisomer). For chlorin A = ¦<S1¦Lz¦S2 > ¦=4.5. Single-site absorption and fluo spectra are reported. PPP calculations were performed. 相似文献
53.
Photochemical hole-burning was used to study optical dephasing in the S1 ← So OO transitions of dimethyl-s-tetrazine, chlorin and free-base porphin in several organic glasses and polymers. The homogeneous width (Γhom) seems to follow a T1.3±0.1 law between 0.4 and 20 K for all guest—host pairs, and extrapolates the lifetime-limited values of each guest for T→0. For a given temperature, Γhom, appears to be related to the number of OH groups in the glass, and to the size of side-groups on the polymer chain. 相似文献
54.
Vainchtein LD Rosing H Thijssen B Schellens JH Beijnen JH 《Rapid communications in mass spectrometry : RCM》2007,21(14):2312-2322
A sensitive and specific high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) assay for the quantitative determination of gemcitabine (dFdC) and its metabolite 2',2'-difluorodeoxyuridine (dFdU) is presented. A 200-microL aliquot of human plasma was spiked with a mixture of internal standards, didanosine, lamivudine and fludarabine, and extracted using solid-phase extraction. Dried extracts were reconstituted in 1 mM ammonium acetate/acetonitrile (97:3, v/v) and 10-microL volumes were injected onto the HPLC system. Separation was achieved on a 150 x 2.1 mm C18 bonded phase endcapped with polar groups (Synergi Hydro-RP column) using an eluent composed of 1 mM ammonium acetate (pH 6.8)/acetonitrile (94:6, v/v). Detection was performed by positive ion electrospray ionization followed by MS/MS. The assay quantifies a range from 0.5 to 1000 ng/mL for gemcitabine and from 5 to 10,000 ng/mL for dFdU using 200 microL of human plasma sample. Validation results demonstrate that gemcitabine and dFdU concentrations can be accurately and precisely quantified in human plasma. This assay is used to support clinical pharmacologic studies with gemcitabine. 相似文献
55.
In the framework of relativistic harmonic confinement model for quarks and antiquarks, the masses of S- and P-wave mesons and pseudoscalar decay constants from light flavour to heavy flavour sectors are computed. The residual two-body
Coulomb interaction and the spin-dependent interaction of the confined one gluon exchange effects (COGEP) such as spin-spin
and spin-orbit interactions are perturbatively incorporated with the confinement energy to get the respective vector-pseudoscalar
meson mass differences. Here we employ the same parametrization and model parameters as used in a recent study of low-lying
hadron masses and leptonic decay widths. The results are being compared with the values obtained from other theoretical models
and the experimental values. 相似文献
56.
Sund Sebastian Sendstad Lars H. Thijssen Jacco J. J. 《Computational Management Science》2022,19(3):457-490
Computational Management Science - Technological innovations often create new markets and this gives incentives to learn about their associated profitabilities. However, this decision depends not... 相似文献
57.
Minglong Liu Vito Thijssen Dr. Seino A. K. Jongkees 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22054-22058
Genetic code reprogramming is a powerful approach to controlled protein modification. A remaining challenge, however, is the generation of vacant codons. We targeted the initiation machinery of E. coli, showing that restriction of the formyl donor or inhibition of the formyl transferase during in vitro translation is sufficient to prevent formylation of the acylated initiating tRNA and thereby create a vacant initiation codon that can be reprogrammed by exogenously charged tRNA. Our approach conveniently generates peptides and proteins tagged N-terminally with non-canonical functional groups at up to 99 % reprogramming efficiency, in combination with decoding the AUG elongation codons either with native methionine or with further reprogramming with azide- and alkyne-containing cognates. We further show macrocyclization and intermolecular modifications with these click handles, thus emphasizing the applicability of our method to current challenges in peptide and protein chemistry. 相似文献
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The quality of surface waters depends on chemical, physical and biological properties. An official definition of normal values of various chemical constituents for the construction of a classification scale of water quality has been in use for some years; water quality of each sampling location is presented on geographical maps by colour codes. The information content of these maps has decreased considerably in recnet years, because of improving water quality. In the method described here, a different selection of class boundaries is used, so that all classes are well populated, and data are weighted to emphasize extreme situations. This improves the information content of the maps, simplifying choices of locations for remedial action. 相似文献