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381.
Gutman I Araujo O Morales DA 《Journal of chemical information and computer sciences》2000,40(3):593-598
For a saturated hydrocarbon with n carbon atoms and m carbon-carbon bonds and with Randic connectivity index chi, two functions, L = L(n,m) and U = U(n,m), are determined, such that L < or = chi < U. These bounds are better than those previously reported; for most chemically relevant values of n and m there exist hydrocarbons for which chi = L or chi = U. 相似文献
382.
B. F. de Araujo H. T. Matsuda J. A. Araujo 《Journal of Radioanalytical and Nuclear Chemistry》1994,187(2):159-168
This work deals with the extraction behavior of neptunium in a high acid Purex Process. The composition of PWR fuel type with 3.2% enrichment, 500 MWd/t burn-up and 100 d cooling time was considered. Two consecutive cold runs were performed in a mock-up facility at IPEN-CNEN/SP with simulated feed solutions containing: 3M HNO3; 1M U; 455 g237Np labeled with239Np; 15 mg Zr l–1, 12 mg Ce l–1, 7 mg Ru l–1 and 13 mg Mo l–1 traced with active isotopes95Zr,141Ce,103Ru and99Mo as FP. A 30 vol% TBP/n-dodecane was used as solvent. Countercurrent experiments were carried out using two 16 stages plexiglass mixer-settlers, at 25°C, during 21 h continuous operation, with O/A ratio of 2 in the extraction section and 9 and 13 in the 1st and 2nd scrubbing sections, respectively. For a 65% organic loading, ca. 77% of neptunium remains in the waste stream, without any Np valence adjustment. 相似文献
383.
Mothé C. G. de Araujo C. R. de Oliveira M. A. Yoshida M. I. 《Journal of Thermal Analysis and Calorimetry》2002,67(2):305-312
Polyurethane composites with bagasse of sugar cane (BSC) at different proportions: 5, 10 and 20 mass/mass% were prepared by
melt mixing method. The thermal behavior of these composites were studied by thermogravimetry (TG/DTG). The influence of fiber
concentration on the kinetic parameters of the composites was studied and a better interaction was suggested between PU/BSC
with 5mass/mass% of fiber. Scanning electron microscopy was carried out to investigate surface morphology.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
384.
Maomao He Jie Li Hesong Han Clarissa Araujo Borges Gabriel Neiman Joachim Justad Rise Piotr Hadaczek Rima Mendonsa Victoria R. Holm Ross C. Wilson Krystof Bankiewicz Yumiao Zhang Corinne M. Sadlowski Kevin Healy Lee W. Riley Niren Murthy 《Chemical science》2020,11(33):8973
Reduction sensitive linkers (RSLs) have the potential to transform the field of drug delivery due to their ease of use and selective cleavage in intracellular environments. However, despite their compelling attributes, developing reduction sensitive self-immolative linkers for aliphatic amines has been challenging due to their poor leaving group ability and high pKa values. Here a traceless self-immolative linker composed of a dithiol-ethyl carbonate connected to a benzyl carbamate (DEC) is presented, which can modify aliphatic amines and release them rapidly and quantitatively after disulfide reduction. DEC was able to reversibly modify the lysine residues on CRISPR–Cas9 with either PEG, the cell penetrating peptide Arg10, or donor DNA, and generated Cas9 conjugates with significantly improved biological properties. In particular, Cas9–DEC–PEG was able to diffuse through brain tissue significantly better than unmodified Cas9, making it a more suitable candidate for genome editing in animals. Furthermore, conjugation of Arg10 to Cas9 with DEC was able to generate a self-delivering Cas9 RNP that could edit cells without transfection reagents. Finally, conjugation of donor DNA to Cas9 with DEC increased the homology directed DNA repair (HDR) rate of the Cas9 RNP by 50% in HEK 293T cell line. We anticipate that DEC will have numerous applications in biotechnology, given the ubiquitous presence of aliphatic amines on small molecule and protein therapeutics.Reduction sensitive linkers (RSLs) have the potential to transform the field of drug delivery due to their ease of use and selective cleavage in intracellular environments. 相似文献
385.
Ramn Martínez Felipe Brito Mary Lorena Araujo Fernando Ruette Aníbal Sierraalta 《International journal of quantum chemistry》2004,97(4):854-864
Calculations of several beryllium complexes {[Be(H2O)n]2+ (n = 1–4), [BeOH(H2O)n]+ (n = 1–3), and [Be(OH)2(H2O)n] (n = 1, 2)} were carried out to compare different ab initio (density functional theory, MP2) and parametric (PM3(tm), CATIVIC) methods. Results show that the parametric method CATIVIC gives geometries and energies closer to the ab initio geometries than the PM3(tm) method due to the inclusion of the atomic excitation energies of the neutral atoms as well as the ions and to the dependence of the molecular parameters on the system charge. The molecular electronic density analysis of the Be? O bonds shows that the Be–water interaction in the [Be(H2O)n]2+ complexes can be considered as a closed‐shell interaction with a σ character in the bond while in the [Be(OH)2(H2O)n] complexes the Be? water bond have π character. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004 相似文献
386.
Catalytic cracking of C5+ gasoline over hy zeolite 总被引:1,自引:0,他引:1
Marcelo J. B. Souza Antonio O. S. Silva Valter J. Fernandes Jr Antonio S. Araujo 《Reaction Kinetics and Catalysis Letters》2003,79(2):257-262
The catalytic conversion of a C5+ natural gasoline over the HY zeolite has been studied. The results show the formation of
C2, C3 and C4 hydrocarbons with an apparent activation energy of ca. 39 kJ mol-1.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
387.
M. H. B. Costa O. A. Sant’Anna P. S. de Araujo R. A. Sato W. Quintilio L. V. N. Silva C. R. T Matos I. Raw 《Applied biochemistry and biotechnology》1998,73(1):19-28
Protein stability is one of the most important obstacles for successful formulation in the development of new-generation vaccines.
Here, the 18kDa heat-shock protein (18kDa-hsp) was chemically modified though conjugation with bovine serum albumin or by
esterification with N-hydroxysuccinimide ester of palmitic acid. The biologically active conformation of the protein was preserved
after chemical modification. The immune responses to the recombinant 18kDa-hsp fromMycobacterium leprae were studied in different presentations: free, copolymerized with bovine serum albumin in aggregates (18kDa-hsp-BSA), and
either surface linked to liposomes or entrapped into liposomes. Measuring the antibody production of immunized genetically
selected mice has compared the adjuvant effects of liposomes and proteic copolymer. Among the two liposome preparations, the
strongest response was obtained with the surface-exposed antigen-liposomes. The copolymer 18kDa-hsp-BSA conferred a high titer
of antibody in injected mice, and persisted 70 d after immunization. This approach should prove very useful for designing
more effective vaccines by using 18kDa-hsp as carrier protein. 相似文献
388.
Ferrara Maria Antonieta Bon Elba P. S. Neto Julio Silva Araujo 《Applied biochemistry and biotechnology》2002,98(1-9):289-300
The possibility of using two by-products of the sugar cane industry, molasses and bagasse steam explosion liquor (SEL), for
lignin peroxidase (LiP) production by Phanerochaete chrysosporium was investigated. For comparison, the fungus was initially cultivated in synthetic media containing either glucose, sucrose,
xylose, or xylan as sole carbon sources. The effect of veratryl alcohol (VA) was also investigated in relation to the enzyme
activity levels. Results showed that sucrose was not metabolized by this fungus, which precluded the use of molasses as a
carbon source. Glucose, xylose, and xylan promoted equivalent cell growth. Enzyme levels in the absence of VA were lower than
28 UI/L and in the presence of VA reached 109 IU/L with glucose and 85 IU/L with xylose or xylan. SEL was adequate for P. chrysosporium LiP production as LiP activity reached 90 IU/L. When VA was added to this medium, enzyme concentration increased to 155 IU/L. 相似文献
389.
Ether amine greases are commonly used in the flotation of iron ore, and after use are discarded in the tailings dams. The
aim of this work was to quantify a commercial ether amine using the bromocresol green dye in chloroform. The statistical data
obtained show that the method is characterized by satisfactory accuracy and precision with a detection limit below 1 mg/L.
The recovery obtained was 98.53%, in average. In addition, the method presented here provided a recovery of ether amine contained
in effluents and solids higher than 98%.
The article is published in the original. 相似文献
390.
C.J. da Silva M.T. de Araujo E.A. Gouveia A.S. Gouveia-Neto 《Applied physics. B, Lasers and optics》2000,70(2):185-188
The temperature effect upon infrared-to-visible frequency upconversion fluorescence emission in Yb3+-sensitized Er3+-doped germanosilicate optical fibers excited with cw radiation at 1.064 μm is investigated. The experimental results revealed
an eightfold enhancement in the visible upconversion emission intensity as the fiber temperature was increased from 17 °C
to 180 °C. The fluorescence emission enhancement is attributed to the temperature-dependent multiphonon-assisted anti-Stokes
excitation process of the ytterbium sensitizer. A theoretical approach that takes into account a sensitizer absorption cross-section,
which depends on the phonon occupation number, has proven to agree very well with the experimental data
Received: 6 April 1999 / Revised version: 27 August 1999 / Published online: 27 January 2000 相似文献