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51.
52.
53.
THE RELATIONSHIP BETWEEN CAROTENOID PIGMENTS AND RESISTANCE TO RADIATION IN NON-PHOTOSYNTHETIC BACTERIA 总被引:2,自引:0,他引:2
Abstract— A radiation-resistant Micrococcus sp. and a colorless mutant subject to gamma radiation were found to have identical killing curves. Similar results were obtained with ultraviolet light. However when exposed to visible light in the presence of the photosensitizer, toluidine blue, the pigmented wild-type was unaffected whereas the colorless mutant was killed. Sarcina lutea and a colorless mutant were killed at similar rates following exposure to x-rays and U.V. light, whereas previous studies have demonstrated that the pigmented wild-type is protected against lethal photosensitizations by visible light. It is concluded that the effect of carotenoid pigments in radiation damage is limited to protecting cells against the lethal effects of visible light and is without effect at shorter wavelengths. 相似文献
54.
J. Barritt R. T. Mease F. Garelli B. Saladini M. Harris H. A. Neville W. C. Fritz . Phillips A. P. Mathews A. Itkina Plechan H. Pauly E. Mönch M. C. Marsh A. P. Sakoschtschikow R. Smith J. Ph. Peper T. Dokkum S. N. Schoorl D. A. Clibbens B. P. Ridge F. RSiefert H. Wolff und K. Lindner 《Fresenius' Journal of Analytical Chemistry》1936,105(5-6):222-240
Ohne Zusammenfassung 相似文献
55.
Borrett VT Gan TH Lakeland BR Leslie DR Mathews RJ Mattsson ER Riddell S Tantaro V 《Journal of chromatography. A》2003,1003(1-2):143-155
Amiton [O,O-diethyl S-[2-(diethylamino)ethyl] phosphorothiolate], is an organophosphorus chemical included in Schedule 2 of the Chemical Weapons Convention (CWC). Verification provisions under the CWC rely on the existence of a database of analytical information for scheduled chemicals and related compounds. Little analytical information is available for amiton. In this study, gas chromatography-mass spectrometry (GC-MS) characterisation of amiton and its typical impurities (including by-products and degradation products), supported by selective GC detection and 31P NMR data, was undertaken. Twenty-one compounds, including a by-product unique to amiton from an industrial source, were identified. Involatile degradation products of amiton were derivatised to enable their identification by GC-MS. The recovery of amiton from matrices that may be expected in an inspection scenario (i.e. concrete, paint, rubber and soil) was also examined. Paint and concrete matrices were the most useful matrices for the detection of amiton, and its by-products and degradation products. Amiton was readily detected in these matrices after 28 days. 相似文献
56.
Manh Hoang Joseph F. Mathews Kerry C. Pratt 《Reaction Kinetics and Catalysis Letters》1997,61(1):21-26
Para-selectivity of ZSM-5 zeolites with similar bulk Si/Al ratio, but different particle size and surface Al concentration has
been investigated in toluene disproportionation. Results showed that enhancedpara-selectivity is a consequence not only of the particle size but also of the external surface aluminium concentration in the
particles. 相似文献
57.
Nine compounds, namely Li3BO3, -Li4B2O5, β-Li4B2O5, Li6B4O9, -LiBO2, Li2B4O7, Li3B7O12, LiB3O5 and Li2B8O13 in the Li2O–B2O3 system have been synthesized and characterized. The unit-cell parameters, density and solubility in water at room temperature of all the compounds are reported. The densities of the compounds were found to be in the 1.90–2.50 g cm−3 range, while their solubility in water at room temperature was in the 0.91–8.64×10−2 g cm−3 range. Determination of the thermal stability of the compounds by quenching and differential thermal analysis (DTA) showed that only -LiBO2 and Li2B4O7 retained their original symmetry up to their congruent melting at 1121 and 1188 K, respectively, in air. 相似文献
58.
Cover-Incomparability Graphs of Posets 总被引:1,自引:1,他引:0
Boštjan Brešar Manoj Changat Sandi Klavžar Matjaž Kovše Joseph Mathews Antony Mathews 《Order》2008,25(4):335-347
Cover-incomparability graphs (C-I graphs, for short) are introduced, whose edge-set is the union of edge-sets of the incomparability
and the cover graph of a poset. Posets whose C-I graphs are chordal (resp. distance-hereditary, Ptolemaic) are characterized
in terms of forbidden isometric subposets, and a general approach for studying C-I graphs is proposed. Several open problems
are also stated. 相似文献
59.
The quantitative impact of NLO-QCD corrections for searches of large and warped extra dimensions at hadron colliders are investigated
for the Drell-Yan process. The K-factor for various observables at hadron colliders are presented. Factorisation, renormalisation
scale dependence and uncertainties due to various parton distribution functions are studied. Uncertainties arising from the
error on experimental data are estimated using the MRST parton distribution functions.
相似文献
60.
Christopher M. Andolina Ryan A. Mathews Janet R. Morrow 《Helvetica chimica acta》2009,92(11):2330-2348
Direct excitation europium(III) luminescence spectroscopy is used to study the speciation of aqueous europium(III) ions at micromolar concentrations and near neutral pH. The pH and concentration dependence of the europium(III) 7F0→5D0 excitation peak is consistent with the formation of both mononuclear and dinuclear europium(III) hydroxide complexes at pH 6.5. Luminescence intensity and lifetime quenching studies in the presence of NdIII at pH 5.0 and 6.5 support the formation of a dinuclear complex at pH 6.5. Steady state excitation and time‐resolved luminescence spectroscopy are consistent with the formation of innersphere nitrate and fluoride complexes, but outersphere perchlorate and chloride complexes at pH 6.5 and 5.0. 相似文献