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91.
Molnár Z Mészáros E Szilágyi Z Rosén S Emri T Pócsi I 《Applied biochemistry and biotechnology》2004,118(1-3):349-360
Morphologic and physiologic changes taking place in carbon-limited submerged cultures of Aspergillus nidulans ΔflbA and fadA
G203R
strains were studied. Loss-of-function mutation of the flbA gene resulted in an altered germination with unusually thick germination tubes, “fluffy” pellet morphology, as well as a
reduced fragmentation rate of hyphae during autolysis. In the fadA
G203R
mutant strain, conidiophores formed in the stationary phase of growth, and the size of pellets shrank considerably. There
were no significant differences in the generation of reactive oxygen species (ROS) and in the specific catalase and superoxide
dismutase activities by the tested mutants and the appropriate parental strains. Therefore, the participation of ROS or antioxidative
enzymes in FadA/FlbA signaling pathways seems to be unlikely in submerged cultures. On the other hand, earlier increases in
the extracellular protease and ammonia production were recorded with the ΔflbA strain, whereas the protease and ammonia production of the fadA
G203R
mutant lagged behind those of the wild-type strains. Similar changes in the time courses of the induction of γ-glutamyltranspeptidase
and the degradation of glutathione were observed. These results suggest that FadA/FlbA signaling may be involved in the mobilization
of protein and peptide reserves as energy sources during carbon starvation. 相似文献
92.
Summary Amino acids have been esterified with n-butanol and isobutanol in the presence of perchloric acid. It has been established that in the concentration range of [H2O]/[n-BuOH]=0.10–0.40 esterification can be utilized for the determination of alanine, glycine, valine, leucine, proline, methionine, aspartic acid, phenylalanine, tyrosine, glutamic acid, lysine, arginine, histidine and cystine. In the case of [H2O]/[i-BuOH] =0.05–0.20 the esterification yield decreases from 100% to 70%, in proportion to the water content. 相似文献
93.
A new gamma-ray spectrum catalog and library for PGAA 总被引:1,自引:0,他引:1
Zs. Révay G. L. Molnár T. Belgya Zs. Kasztovszky R. B. Firestone 《Journal of Radioanalytical and Nuclear Chemistry》2001,248(2):395-399
New measurements have been performed at the PGAA facility at the Budapest Research Reactor (BRR) in order to create a prompt -ray catalog for qualitative and quantitative analysis. The measured spectra were accurately analyzed by HYPERMET-PC. Prompt -ray energies and associated -ray production cross-sections have been determined by internal standardization. The resulting catalog contains prompt -ray data from neutron capture and other reactions such as (n,), and decay -ray data from short-lived reaction products. Data have been measured for nearly all stable elements, from hydrogen to uranium. Generally, data for several isotopes are given, to enable isotopic analysis as well. The whole library, including elemental spectra, will be available as a book. 相似文献
94.
M. Zagyvai N. Vajda J. Groska Zs. Molnár E. Bokori P. Szeredy 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(1):49-58
A method using DGA resin (N,N,N′,N′-tetra-n-octyldiglycolamide on an inert support) was developed for the rapid analysis of actinides in urine samples. Samples acidified with HCl to 4 M were loaded directly (without digestion) onto a DGA column. Actinides were stripped simultaneously, α-sources were prepared by co-precipitation with NdF3. Americium, plutonium and uranium were separated with acceptable high recoveries (40–80%). The americium, plutonium and uranium content of 100–200 ml urine samples was determined within 24 h with detection limits as low as 0.01 Bq l?1. Based on model experiments using 14C-spiked urea, it was proven that high urea content can affect americium separation deleteriously due to irreversible fixing of americium on DGA resin. 相似文献
95.
Korös A Hanczkó R Jámbor A Qian Y Perl A Molnár-Perl I 《Journal of chromatography. A》2007,1149(1):46-55
The extraction of ornithine, lysine, putrescine, cadaverine, 1,7-diaminoheptane, spermidine and spermine from biological tissues was optimized for HPLC quantitation as their o-phthalaldehyde/ethanethiol/fluorenylmethyl chloroformate (OPA/ET/FMOC) derivatives. In applying perchloric acid deproteinization two approaches have been followed: (i) deproteinization with subsequent neutralization by potassium hydroxide and lyophilization, and (ii) deproteinization without neutralization and lyophilization. Neutralization and lyophilization resulted in the loss of free biogenic amines. HPLC analysis of ornithine (Orn), lysine (Lys), putrescine (Put), cadaverine (Cad), 1,7-diaminoheptane (Dah), spermidine (Spd) and spermine (Spm) content of biological tissues as their OPA/ET/FMOC derivatives was performed in the supernatant of perchloric acid-deproteinized samples (model solutions and tissues) with an average reproducibility of < or =2.6% relative standard deviation (RSD), including recovery of sample treatment and chromatography. 相似文献
96.
Derivatization yields of different esters (methyl, ethyl, n-propyl, isopropyl, n-butyl and isobutyl) of citric, malic and isocitric acids with various acylating agents, such as acetic anhydride, propionic anhydride, trifluoroacetic anhydride and heptafluorobutyric anhydride, were investigated. The formation of acylated malic and isocitric acid esters is rapid and quantitative whereas the acylation of citric acid esters was slow and partial in most instances. It was found that selective analytical conditions can be achieved with the O-heptafluorobutyryl n-butyl esters. The analytical applicability of the separation and determination of the malic, isocitric and citric acid contents of model solutions and of pressed lemon juice is discussed. Concentrations of 1.2 × 10?3 ?9.0 × 10?3g per 100 g of isocitric acid and 4.2 × 10?3 ?3.5 × 10?2 g per 100 g of malic acid in the presence of 9.3 × 10?1 g per 100 g of citric acid were measured with relative standard deviations of 7.5 and 4.2%, respectively. 相似文献
97.
P. K. Anastasovski T. E. Bearden C. Ciubotariu W. T. Coffey L. B. Crowell G. J. Evans M. W. Evans R. Flower S. Jeffers A. Labounsky B. Lehnert M. Mészáros P. R. Molnár J. P. Vigier S. Roy 《Foundations of Physics Letters》2000,13(2):179-184
It is shown that the Lehnert field equations in vacuum, with concomitant space charge and current, can be derived straightforwardly from standard gauge theory applied in vacuum, using the concept of covariant derivative and Feynman's universal influence. The Lehnert and Proca field equations are shown to be inter-related through the well-known de Broglie theorem, in which the photon mass can be interpreted as finite. These ideas go some way towards addressing the inconsistency inherent in Maxwell's famous displacement current, which has no concomitant vacuum space charge. 相似文献
98.
Varga M. Mulas G. Cocco G. Molnár Á. 《Journal of Thermal Analysis and Calorimetry》1999,56(1):305-310
Amorphous PdZr, PdCuZr and PdCuSi alloy ribbons and powders are characterized by DSC, XRD and XPS in the as-received state
and after treatments with oxygen, hydrogen or dilute hydrogen fluoride solution. Zr-containing alloys are shown to undergo
substantial structural changes resulting in palladium enrichment on their surface, whereas no apparent changes in the bulk
structure are found for PdCuSi. Catalytic activity and selectivity of the pretreated samples were tested in the hydrogenation
of phenylacetylene.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
99.
Á. Vincze L. Halasz J. Solymosi B. Ágai I. Kása A. Molnár Á. Sáfrány 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(3):615-619
In this paper, the development of a new-type of resin is presented, which contains selective complexing and scintillating
molecules in a chemically bonded form. The resin material is produced via radiation polymerization of a solution of 2-(4-allyloxy-phenyl)-5-phenyl
oxazole, 5-(allyloxy-phenyl)-2-[4-(5-phenyl-oxazole-2-il)-phenyl] oxazole, diethylene glycol dimethacrylate (DEGMA), styrene
and the allyl derivative of a 18C6 crown ether-dicarbolic acid complexing agent. The product is a macroporous polymer matrix
that shows fluorescent properties and ion binding capacity excellent for radioanalytical purposes. 相似文献
100.
L. B. Crowell P. K. Anastasovski T. E. Bearden C. Ciubotariu W. T. Coffey G. J. Evans M. W. Evans R. Flower S. Jeffers A. Labounsky B. Lehnert M. Mészáros P. R. Molnár J. P. Vigier S. Roy 《Foundations of Physics Letters》2000,13(2):193-196
Recent data obtained by LEP1 are discussed and their potential implication for the existence of a Z particle. This letter advocates that this fits within the basic tenet of an SU(2)×SU(2) extended theory of the standard model of electroweak interactions. This extended electroweak model is motivated by nonabelian electrodynamics that provides an effective calculus for nonlinear optics. 相似文献