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11.
Vargas F Rivas C Méndez H Fuentes A Fraile G Velásquez M 《Journal of photochemistry and photobiology. B, Biology》2000,58(2-3):108-114
The phototoxic anti-cancer drug flutamide is photolabile under UV-B light in either aerobic or anaerobic conditions. Irradiation of a methanol solution of this drug produces several photoproducts, one by photoreduction of the nitro group, one by rupture of the aromatic-NO2 bond of the parent compound, two as a result of the rupture of the CO-NH bond and one derived from the photoreduction product by scission of the aromatic-NH2 bond. Flutamide shows a photohemolytic effect on human erythrocytes and photoinduces lipid peroxidation. Studies on peripheral blood polymorphonuclear cells (neutrophils) demonstrated the phototoxicity of flutamide as well as inhibition of the cytotoxicity respiratory burst by the photoproduct derived from its photoreduction. The results suggest that the inhibition of the respiratory burst observed in phorbol myristate acetate (PMA)-activated cells is mediated by photosensitization and concomitant singlet oxygen production and/or formation of toxic photoproducts. 相似文献
12.
Bergquist Peter L. Te’o V. S. Junior Gibbs Moreland D. Cziferszky Angela C. E. De Faria Fabricia P. Azevedo Maristela O. Nevalainen K. M. Helena 《Applied biochemistry and biotechnology》2002,98(1-9):165-176
Cost-effective production of enzymes for industrial processes makes the appropriate selection of the host-vector expression
system critical. We have developed two systems for the bulk production of bleaching enzymes from thermophiles. Kluyveromyces lactis has been developed as a secretion host employing expression vectors based on the 2μ-like plasmid pKD1 of Kluyveromyces drosophilarium. Our second system involves the filamentous fungus Trichoderma reesei. Fusion and nonfusion vectors have been constructed using the strong cellobiohydrolase 1 (cbh1) promoter. The KEX2 protease cleavage site and a 6 × HIS-tag have been incorporated to facilitate both cleavage and purification
of the mature foreign proteins. 相似文献
13.
Spectroscopic characterization of mineral crystals produced by the bacterium Azospirillum brasilense
Kamnev AA Antonyuk LP Chernyshev AV Ignatov VV De Vargas MC 《Analytical and bioanalytical chemistry》1996,355(5-6):739-741
The results of spectroscopic structural and trace elemental analyses of mineral crystals produced by the soil nitrogen-fixing bacterium Azospirillum brasilense cultivated in a synthetic medium are presented and discussed. The mineral formed is shown to have a structure close to struvite (MgNH(4)PO(4) x 6H(2)O; ASTM file No. 15-762) with some differences which may be attributed to the presence of isomorphic admixtures of other cations (struvite is known to have a variety of forms). AAS/AES and ion chromatography analyses for a number of biologically important microelements and their role in the formation of the crystal structure, as well as some questions related to biomineralization are also discussed. 相似文献
14.
Brian F.G. Johnson Jack Lewis William J.H Nelson Maria D. Vargas Dario Braga Mary McPartlin 《Journal of organometallic chemistry》1983,246(2):c69-c73
The high nuclearity mixed metal cluster monoanions [Os10C(CO)24Cu(NCMe)]? (I) and [Os10C(CO)24AuPPh3]? (II) have been obtained by reaction of the carbido-dianion [Os10C(CO)24]2? (III) with one equivalent of [Cu(NCMe)4] [BF4] and Ph3PAuCl, respectively, in CH2Cl2. X-ray analysis of the [PPh3Me]+ salts of I and II show that the Cu and Au ligands have added to capping tetrahedra of the dianion III in μ3- and μ2-bridging positions, respectively. 相似文献
15.
Ana M. Vargas 《Rendiconti del Circolo Matematico di Palermo》1995,44(2):273-282
LetM
e
0
be the maximal operator over segments of length 1 with directions belonging to a Cantor set. It has been conjectured that
this operator is bounded onL
2. We consider a sequence of operators over finite sets of directions converging toM
e
0
. We improve the previous estimate for the (L
2,L
2)-norm of these particular operators. We also prove thatM
e
0
is bounded from some subsets ofL
2 toL
2. These subsets are composed of positive functions whose Fourier transforms have a very weak decay or are supported in a vertical
strip.
Partially supported by Spanish DGICYT grant no. PB90-0187. 相似文献
16.
LetEçS 1 be a set with Minkowski dimensiond(E)1. We consider the Hardy-Littlewood maximal function, the Hilbert transform and the maximal Hilbert transform along the directions ofE. The main result of this paper shows that these operators are bounded onL rad p (R2) forp>1+d(E) and unbounded whenp<1+d(E). We also give some end-point results. 相似文献
17.
P. Abreu W. Adam T. Adye E. Agasi R. Aleksan G. D. Alekseev P. Allport S. Almehed F. M. L. Almeida Junior S. J. Alvsvaag et al. 《Zeitschrift fur Physik C Particles and Fields》1994,63(1):3-15
The average lifetime ofB hadrons was measured using data collected with the DELPHI detector at the LEP collider during 1991 and 1992. The measurement was performed using two different anayses. The first method was an improvement on a previous technique, which used charged particle impact parameter distributions. This analysis measured an average lifetime forB hadrons of
相似文献
18.
Sanford TW Allshouse GO Marder BM Nash TJ Mock RC Spielman RB Seamen JF McGurn JS Jobe D Gilliland TL Vargas M Struve KW Stygar WA Douglas MR Matzen MK Hammer JH De Groot JS Eddleman JL Peterson DL Mosher D Whitney KG Thornhill JW Pulsifer PE Apruzese JP Maron Y 《Physical review letters》1996,77(25):5063-5066
19.
Thereza Christina Vessoni Penna Marina Ishii Adalberto Pessoa Junior Laura de Oliveira Nascimento Luciana Cambricoli de Souza Olivia Cholewa 《Applied biochemistry and biotechnology》2004,114(1-3):453-468
To determine the influence of various culture conditions, transformed cells of Escherichia coli expressing recombinant green fluorescent protein (GFPuv) were grown in nine cultures with four variable conditions (storage
of inoculated broth at 4°C prior to incubation, agitation speed, isopropyl-β-d-thiogalactopyranoside [IPTG] concentration, and induction time). The pelleted cells were resuspended in extraction buffer
and subjected to the three-phase partitioning (TPP) extraction method. To determine the most appropriate purification resin,
protein extracts were eluted through one of four types of HiTrap hydrophobic interaction chromatography (HIC) columns prepacked
with methyl, butyl, octyl, or phenyl resins and analyzed further on a 12% sodium dodecylsulfatepolyacrylamidegel. With Coomassie
staining, a single band between 27 (standard GFPuv) and 29 kDa (molecular weight standard) was visualized for every HIC column
sample. TPP extraction with HIC elution provided about 90% of the GFPuv recovered and eight-fold GFPuv enrichment related
to the specific mass. Rotary speed and IPTG concentration showed, respectively, greater negative and positive influences on
GFPuv expression at the beginning of the logarithmic phase for the set culture conditions (37°C, 24-h incubation). 相似文献
20.
[reaction--see text] The type 2 intramolecular Diels-Alder cycloaddition utilizing N-acylnitroso dienophiles provides an efficient entry into bridged oxazinolactams. In contrast to the bimolecular counterpart, the reaction is completely regioselective. Structural characterization of the cycloadducts allows for evaluation of the olefin distortion and the degree of pyramidalization of the bridgehead oxazinolactam. 相似文献
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