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161.
Dini D Calvete MJ Hanack M Meneghetti M 《The journal of physical chemistry. A》2008,112(37):8515-8522
The photophysical properties of four axially substituted indium phthalocyanines, namely, 2,(3)-tetra- tert-butyl-phthalocyaninato indium chloride ( 1), 2,(3)-tetra-[(3,5-di- tert-butyl)-phenyloxy]-phthalocyaninato indium bromide ( 2), 2,(3)-tetra-[(3,5-di- tert-butyl)-phenyloxy]-phthalocyaninato indium iodide ( 3), and 2,3-octa-[(2-hexyl)-ethyloxy]-phthalocyaninato indium trifluoroacetate ( 4), have been investigated, and their optical limiting properties with nanosecond light pulses were evaluated. All complexes behave as reverse saturable absorbers in the range of 400-625 nm due to a triplet-triplet excited-state transition. Excited-state absorption cross sections and triplet state lifetimes are not significantly affected by the nature of the axial ligand. On the other hand, remarkable differences in the variation of nonlinear transmittance are observed for 1- 4 due to significantly different intersystem crossing rates. Heavier axial ligands in phthalocyanines 2 and 3 produce the largest variations of nonlinear transmission (heavy-atom effect). Complex 1 in polystyrene matrix shows reversible nonlinear absorption when incident fluence does not exceed 0.025 J cm (-2). 相似文献
162.
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164.
Dr. Malika Makhlouf Brahmi Dr. Cyril Portmann Danilo D'Ambrosio Dr. Tom M. Woods Damiano Banfi Patrick Reichenbach Laeticia Da Silva Emilie Baudat Dr. Gerardo Turcatti Prof. Dr. Joachim Lingner Prof. Dr. Karl Gademann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(14):4596-4601
By using the Telospot assay, 27 different extracts of cyanobacteria were evaluated for telomerase inhibition. All extracts showed varying, but significant activity. We selected Microcystis aeruguinosa PCC 7806 to identify the active compound and a bioassay guided fractionation led us to isolate mixtures of sulfoquinovosyl diacylglycerols (SQDGs), which were identified by 2D NMR and MS/MS experiments. Pure SQDG derivatives were then synthesized. The IC50 values of pure synthetic sulfoquinovosyl dipalmitoylglycerol and the monopalmitoylated derivative against telomerase were determined to be 17 and 40 μM , respectively. A structure–activity relationship study allowed the identification of compounds with modified lipophilic acyl groups that display improved activity. 相似文献
165.
This paper presents the analysis of linear elastic trusses proposed by Valentino Cerruti in his graduation thesis. While Cerruti
is famous among rational mechanicians, very little is known on this work of his. We will consider the work in some detail,
putting into evidence the main subjects dealt with by the author: redundant trusses and uniform resistance. We will also provide
a comparison with his contemporaries and some critical comments. 相似文献
166.
Danilo Bazzanella 《Periodica Mathematica Hungarica》2013,66(1):111-117
At present noone knows an unconditional proof that between two consecutive squares there is always a prime number. In a previous paper the author proved that, under the assumption of the Lindelöf hypothesis, each of the intervals [n 2, (n+1)2] ? [1,N], with at most O(N ?) exceptions, contains the expected number of primes, for every constant ? > 0. In this paper we improve the result by weakening the hypothesis in two different ways. 相似文献
167.
168.
This paper presents the theorem proposed by Luigi Federico Menabrea to study linear elastic redundant systems. Some of Menabrea’s
papers on the subject are examined, as well as the criticism and the corrections brought to his first proof. We consider Menabrea’s
work in the frame of the studies of his contemporaries; we try to provide a historical and epistemological background for
Menabrea’s theorem and for its consequences in modern mechanics. 相似文献
169.
Danilo Eduardo Martins Sérgio E. Galembeck 《International journal of quantum chemistry》2024,124(1):e27325
Despite the ubiquitous presence of amine oxides in chemistry, there is no consensus about the nature of the N O bond in these compounds. In this work, we have used electron density analysis to investigate the nature of this bond in substituted amine oxides, R3NO, and have compared it with the nature of the N O bond in hydroxylamines, R2NOR, and model molecules that have well-established chemical bond character. The results showed that the N O bond length and relative stability are proportional to the inductive effect of the substituents. Quantum chemical topology, natural bond orbitals (NBO), and natural resonance theory (NRT) analyses indicated that the N O bond is polar covalent in all the studied amine oxides, but the ionic contribution is different. NBO and NRT analyses revealed that molecules with more electronegative substituents have strongly delocalized N O and N R bonds, whereas molecules with electropositive substituents have localized bonds. 相似文献
170.
Rafael Rodrigues Hatanaka Danilo Luiz Flumignan José Eduardo de Oliveira 《Chromatographia》2009,70(7-8):1135-1142
ASTM D6729 gas chromatographic fingerprinting coupled to pattern-recognition multivariate soft independent modeling of class analogy (SIMCA) chemometric analysis provides an original and alternative approach to screening Brazilian commercial gasoline quality. SIMCA, was performed on gas chromatographic fingerprints to classify the quality of representative commercial gasoline samples selected by hierarchical cluster analysis and collected over a 5 month period from gas stations in São Paulo State, Brazil. Following an optimized ASTM D6729 gas chromatographic-SIMCA algorithm, it was possible to correctly classify the majority of commercial gasoline samples. The method could be employed for rapid monitoring to discourage adulteration. 相似文献