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991.
H. Blumberg J. Fechner A. Hammesfahr P. Herzog A. Kluge J. Voss 《Zeitschrift für Physik A Hadrons and Nuclei》1969,228(4):391-395
TheK-shell particle parameter of the 122 keV transition in152Sm has been investigated using different sources and different experimental arrangements. From our measurements we obtain the mean valueb 2=1.77±0.03. This result deviates from the theoretical value by (6.5±1.5)%. We do not observe hygroscopic effects as reported in Ref. 相似文献
992.
993.
This paper proposes to extend the exploration of mouse melanoma B16 cells death by photodynamic therapy (PDT), under irradiation
with different light sources and in the presence of 5,10,15,20-tetrap-sulphonato-phenyl-porphyrin (TSPP). The viability studies
showed that B16 mouse melanoma is sensitive to photodynamic damage induced by TSPP 1 mM for either one, two, three or four
hours. The control had TSPP added immediately prior to timelapse imaging (no incubation). They were then irradiated with red
light He-Ne laser (λ = 632.8 nm, energy 180 J/cm2 for 20 min). Also, it has been used a laser diode GaInAs 25 mW/cm2, λ = 650 nm. The cells demonstrated clear morphological changes associated with apoptosis by mitochondrial pathway. There
were changes in texture, as expected. Changes appeared to occur more quickly at lamp irradiation than at HeNe and GaInAs diode
laser. Addition of TSPP just prior to exposure and observation, with no incubation, did not result in changes in cell morphology
or cell death. Also, the proteins changes have been observed, because those with high molecular weights have been scissored
under irradiation and this could be reason of the proteins concentrating in the area of low molecular weights, and the dissapearing
of the proteic band of 75 kDa in the electrophoregramm. The immunized animals with B16-TSPP had the highest survival rate
(40 days) by comparison with the control (death at 20 days) or with immunized animals with supernatants B16 (death at 25 days). 相似文献
994.
Andaluzia Matei Constantin P. Niculescu 《Journal of Mathematical Analysis and Applications》2011,379(1):15-25
We consider a displacement-traction boundary values problem for elastic materials, under the small deformations hypothesis, for static processes. The behavior of the material is modeled by a constitutive law involving the subdifferential of a proper, convex, and lower semicontinuous map. The constitutive map and its Fenchel conjugate allow us to construct a bipotential function. Based on this construction, we propose a weak formulation of our mechanical problem. Furthermore, we prove the existence of at least one weak solution and we investigate the uniqueness of the weak solution. We also comment on the relevance of our variational approach, by considering three significant examples. 相似文献
995.
Dan Donescu Valentin Raditoiu Catalin Ilie Spataru Raluca Somoghi Marius Ghiurea Constantin Radovici Radu Claudiu Fierascu Gabriel Schinteie Aurel Leca Victor Kuncser 《European Polymer Journal》2012,48(10):1709-1716
Magnetite alternating copolymers divinylbenzene–maleic anhydride (DVB–MA) composites were prepared by dispersion polymerization. Because magnetite is used as a complex with oleic acid (Fe3O4OLA), the final hybrids show good dispersion of inorganic nanofillers in the polymer matrix. The obtained composites were analyzed by infrared absorption spectrometry, diffuse reflectance in visible light, thermogravimetry, X-ray fluorescence, X-ray diffraction, dynamic light scattering, scanning electron microscopy and vibrating sample magnetometry. The obtained results indicate the successful preparation of magnetite nanoparticles with an average size of about 23 nm dispersed in micrometer size copolymer spherical particles, which relative content can be controlled via the processing parameters. A relationship between the relative content of magnetite nanoparticles and the size of the polymer particles, with direct influence on the diffuse reflectance in the visible domain, was observed. A superparamagnetic behavior was evidenced at room temperature with a blocking temperature lower than as expected from the bulk anisotropy constant and the average size of the magnetite nanoparticles. Both the unexpected low blocking temperature and the observed low specific magnetizations were explained by a defected and poor crystalline structure of the magnetite nanoparticles, giving rise to spin disorder and diminished crystalline anisotropy constant. 相似文献
996.
Dr. Max J. Cryle Dr. Patricia Y. Hayes Prof. Dr. James J. De Voss 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(50):15994-15999
The products of cytochrome P450BM3‐catalysed oxidation of cyclopropyl‐containing dodecanoic acids are consistent with the presence of a cationic reaction intermediate, which results in efficient dehydrogenation of the rearranged probes by the enzyme. These results highlight the importance of enzyme–substrate complementarity, with a cationic intermediate occurring only when the probes used begin to diverge from ideal substrates for this enzyme. This also aids in reconciling literature reports supporting the presence of cationic intermediates with certain cytochrome P450 enzyme/substrate pairs. 相似文献
997.
Laura Trandafir Mioara Alexandru Mihai Constantin Anca Ioniţă Florina Zorilă Valentin Moise 《Radiation Physics and Chemistry》2012,81(9):1513-1515
EN ISO 11137 established regulations for setting or substantiating the dose for achieving the desired sterility assurance level.The validation studies can be designed in particular for different types of products. Each product needs distinct protocols for bioburden determination and sterility testing.The Microbiological Laboratory from Irradiation Processing Center (IRASM) deals with different types of products, mainly for the VDmax25 method. When it comes to microbiological evaluation the most challenging was cotton gauze. A special situation for establishing the sterilization validation method appears in cases of cotton packed in large quantities. The VDmax25 method cannot be applied for items with average bioburden more than 1000 CFU/pack, irrespective of the weight of the package. This is a method limitation and implies increased costs for the manufacturer when choosing other methods.For microbiological tests, culture condition should be selected in both cases of the bioburden and sterility testing. Details about choosing criteria are given. 相似文献
998.
Ioan Valentin Moise Marian Virgolici Constantin Daniel Negut Mihaela Manea Mioara Alexandru Laura Trandafir Florina Lucica Zorila Catalina Mihaela Talasman Daniela Manea Steluta Nisipeanu Maria Haiducu Zamfir Balan 《Radiation Physics and Chemistry》2012,81(8):1045-1050
Museums, libraries and archives are preserving documents that are slowly degrading due to the inherent ageing of the cellulose substrate or to the technological errors of the past (acid paper, iron gall ink). Beside this, large quantities of paper are rapidly damaged by biological attacks following natural disasters and improper storage conditions.The treatment of paper documents with ionizing radiation can be used for mass decontamination of cultural heritage items but conservators and restaurators are still reserved because of the radiation induced degradation.We conducted a study for establishing the dose needed for the effective treatment of paper documents, taking into account the biological burden and the irradiation effects on paper structure. We used physical testing specific to paper industry and less destructive analytical methods (thermal analysis).Our results show that an effective treatment can be performed with doses lower than 10 kGy. Old paper appears to be less affected by gamma radiation than recent paper but the sampling is highly affected by the non-uniform degree of the initial degradation status. The extent of testing for degradation and the magnitude of acceptable degradation should take into account the biological threat and the expected life time of the paper documents. 相似文献
999.
1000.
Rondão R Seixas de Melo J Schaberle FA Voss G 《Physical chemistry chemical physics : PCCP》2012,14(5):1778-1783
A comprehensive investigation of the solution photophysics of a 5,5'-methylene-bridged polymeric indigo, a statistical copolymer consisting of indigo and N-acetylindigo units, was performed in organic solvents at room temperature and further compared with indigo. A complete spectral and photophysical characterization based on photoacoustic calorimetry, steady-state and time-resolved fluorescence data was undertaken. A fluorescence quantum yield of 0.00037 and an intersystem crossing singlet-to-triplet quantum yield of 0.006 (close to the value for indigo) were obtained, leading to a value of 0.9936 for the S(1) → S(0) internal conversion (IC) quantum yield. Spectral and photophysical characteristics similar to indigo were obtained with, however, a special signature: it (mainly) decays single exponentially (in contrast with indigo, found to decay bi-exponentially), with a decay time value of 40-50 ps and an even more efficient S(1) → S(0) IC deactivation channel, related to an efficient energy migration within an energetic ladder of the polymer chromophoric segments. The photochemistry of this polymer, namely the degradation under light excitation, was also investigated and the obtained photoreaction quantum yield (?(R)) in DMF was found to be 0.003, which is lower than the previously determined value for indigo in the same solvent (?(R) = 0.0078). The overall data indicate that although the polymer and indigo have a close finger-print, the former is more stable which is suggested to be due to the additional intramolecular energy transfer process (within different chromophoric units) found with the polymer. 相似文献