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21.
Fabrice Burel Hassan Oulyadi Claude Bunel Vladimir Grishchenko Natalya Busko Antonina Barantsova Vitaly Boiko 《Journal of Polymer Research》2011,18(6):2265-2273
Azo-bis(isobutyroamidoxime) was synthesized and used as functionalized initiator to prepare a liquid isoprene bearing amidoxime
end groups via radical polymerization. The polymer was characterized by FT-IR, Gel Permeation Chromatography and NMR. In particular,
the structure of the polymer was investigated using 1D and 2D NMR techniques. The distribution of the different isoprene units
(1,4-trans, 1,4-cis, 1,2 and 3,4), as well as the structure of the amidoxime end-groups was determined. It was found that
the structure of the end groups was governed by the steric hindrance of the initiator. Only 1,4 and 4,1 functionalized end
units were evidenced, with a majority of 4,1 end units. 相似文献
22.
Naumenko NF Abbott BP 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(10):2181-2187
The mechanism of SAW transformation with variation of film thickness is investigated in a piezoelectric substrate with a metal grating overlaid by a dielectric film, via simulation and visualization of the acoustic fields. By way of example, two orientations of lithium niobate substrates are analyzed, YX-LN and 128°YX-LN, with a Cu grating and an isotropic silica glass overlay. The motions, which follow the wave propagation in the sagittal plane, are visualized within two periods of the grating, with added contour plots showing the shear horizontal displacements. The continuous transformation of the wave's nature is investigated for each wave propagating in the analyzed material structures when the film thickness is increased from zero to a few wavelengths. The examples of the SAW transformation into boundary waves and into plate modes of different polarization have been found and investigated. The behavior of the SAW characteristics in the grating is correlated with transformation of the wave structure with increasing overlay thickness. 相似文献
23.
A bifunctional oligonucleotide integrates in situ synthesis of a fluorogenic silver cluster with recognition of a target DNA sequence. With the template C(3)AC(3)AC(3)GC(3)A, a complex forms with 10 silver atoms that possesses electronic transitions in the near-infrared and that is detected at nanomolar concentrations using diode laser excitation. Pendant to this cluster encoding region, the recognition component binds a target DNA strand through hybridization, and decoupling of these two regions of the composite sensor renders a modular sensor for specific oligonucleotides. A target is detected using a quencher strand that bridges the cluster template and recognition components and disturbs cluster binding, as indicated by static quenching. Competitive displacement of the quencher by the target strand restores the favored cluster environment, and our key finding is that this exchange enhances emission through a proportional increase in the number of emissive clusters. DNA detection is also accomplished in serum-containing buffers by taking advantage of the high brightness of this fluorophore and the inherently low endogenous background in the near-infrared spectral region. Cluster stability in this biological environment is enhanced by supplementing the solutions with Ag(+). 相似文献
24.
Olga P. Tkachenko Alexander Yu. Stakheev Leonid M. Kustov Igor V. Mashkovsky Maurits van den Berg Wolfgang Grünert Natalya Yu. Kozitsyna Zhanna V. Dobrokhotova Valery I. Zhilov Sergei E. Nefedov Michael N. Vargaftik Ilya I. Moiseev 《Catalysis Letters》2006,112(3-4):155-161
The heterobimetallic lantern complex Pd(μ-OOCMe)4Zn(OH2) was found to be readily reduced with H2 under fairly mild conditions (150–250 °C, 5–10% H2/He) both in the carbon-supported and crystalline states to afford a Pd–Zn nanoalloy as evidenced by the ICP elemental analysis,
EXAFS, XANES and XRD data.
相似文献
25.
Ekaterina Pashkina Alina Aktanova Irina Mirzaeva Ekaterina Kovalenko Irina Andrienko Nadezhda Knauer Natalya Pronkina Vladimir Kozlov 《International journal of molecular sciences》2021,22(14)
Cucurbit[7]uril (CB[7]) is a molecular container that may form host–guest complexes with platinum(II) anticancer drugs and modulate their efficacy and safety. In this paper, we report our studies of the effect of CB[7]–oxaliplatin complex and the mixture of CB[7] and carboplatin (1:1) on viability and proliferation of a primary cell culture (peripheral blood mononuclear cells), two tumor cell lines (B16 and K562) and their activity in the animal model of melanoma. At the same time, we studied the impact of platinum (II) drugs with CB[7] on T cells and B cells in vitro. Although the stable CB[7]–carboplatin complex was not formed, the presence of cucurbit[7]uril affected the biological properties of carboplatin. In vivo, CB[7] increased the antitumor effect of carboplatin, but, at the same time, increased its acute toxicity. Compared to free oxaliplatin, its complex with CB[7] shows a greater cytotoxic effect on tumor cell lines B16 and K562, while in vivo, the effects of the free drug and encapsulated drug were comparable. However, in vivo studies also demonstrated that the encapsulation of oxaliplatin in CB[7] lowered the toxicity of the drug. 相似文献
26.
In this article we explore the role of innovation champions and the ways innovation is championed and promoted in five selected UK megaprojects. To date, this research area is surprisingly under-explored in the megaproject management literature. The study is based on thirty interviews with innovation champions to capture their own perceptions and narratives on the ways innovation is stimulated and promoted in megaprojects, combined with relevant textual materials. Innovation was commonly defined as a step change or best practice that creates value that could be financial, environmental, societal etc. The data demonstrate the role of CEOs and their collaboration with innovation champions and academic partners in introducing innovation into the vocabulary of megaprojects, developing and formalising innovation strategy, and transferring experiences across megaprojects. The data show the ways different communication channels are used to promote innovations by champions such as forums, portals, platforms, campaigns, events etc. 相似文献
27.
28.
V. A. Sadykov Svetlana N. Pavlova Galina V. Zabolotnaya Raisa I. Maximovskaya Sergei V. Tsybulya Elena B. Burgina Vladimir I. Zaikovskii Galina S. Litvak Marina V. Chaikina Valerii V. Lunin Natalya N. Kuznetsova Rustum Roy Dinesh K. Agrawal 《Materials Research Innovations》1999,2(6):328-337
High-power ball mill activation of the mixture of hydrated zirconium and lanthanum salts (oxonitrates, oxochlorides) with
ammonium phosphate followed by hydrothermal treatment at temperatures not exceeding 200°C and a nearly neutral pH was found
to yield crystalline dispersed phase of a cubic NH4Zr2(PO4)3 type along with admixtures of disordered orthorhombic compounds of a zirconium orthophosphate type. In the same conditions
and at the same Zr/P ratio, hydrothermal treatment of gels obtained by reacting mixed zirconium and lanthanum nitrates solutions
with ammonium phosphates yields no crystalline products, and only treatment in acid media generates a phase of the α-ZrPO4(OH) type coexisting with the NH4Zr2(PO4)3 phase if polyethylene oxide is present. X-ray powder diffraction, transmission electron microscopy, 31MAS-NMR, FTIRS and thermal analysis were applied to elucidate factors affecting crystallization of complex zirconium phosphates
in the hydrothermal conditions. The most essential factor appears to be generation of some nuclei of zirconium phosphates
under high pressures developed in the course of mixed solids mechanical activation. These nuclei are embedded into matrix
of such well-crystallized solid products as ammonium nitrate or chloride. Hence, metastable cubic or orthorhombic structure
of the phases obtained via mechanical activation route can be assigned to the nuclei-matrix orientation relationship. Due
to easily scaled-up synthesis procedure, these results appear to be very promising for manufacturing of dispersed framework
zirconium phosphates as acid catalysts or fast proton conductors.
Received: 18 November 1998 / Reviewed and accepted: 2 December 1998 相似文献
29.
Rimma V. Golovnya Margarita B. Terenina Natalya I. Krikunova Vladimir P. Yuryev Tamara A. Misharina 《Starch - St?rke》2001,53(6):269-277
The binding absorption of individual alcohols, ketones, alkyl acetates and their mixtures — used as aroma compounds — from aqueous solutions by corn starch cryotextures was studied by capillary gas chromatography at different starting concentrations of the odourants (1—25 mmol/L). The amount of compound sorbed by the cryotextures increases with concentration of this compound in the initial sol and increasing length of the alkyl chain in the corresponding compound. Linear equations describing the concentration dependence were proposed. The presence of octanol in the mixture increases the binding of hexanol as compared to hexanol alone. The methods of scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy, differential scanning microcalorimetry (DSC) and scanning tunneling microscopy (STM) were used for estimation of the microstructure of sols, and cryotextures, and for the determination of supramolecular complex formation in the systems odourant/cryotexture and odourant/sol. It was shown that waxy corn cryotextures do not form supramolecular complexes with aroma compounds. 相似文献
30.
Smirnova NA Romanienko PJ Khil PP Camerini-Otero RD 《Reproduction (Cambridge, England)》2006,132(1):67-77
Spo11, a meiosis-specific protein, introduces double-strand breaks on chromosomal DNA and initiates meiotic recombination in a wide variety of organisms. Mouse null Spo11 spermatocytes fail to synapse chromosomes and progress beyond the zygotene stage of meiosis. We analyzed gene expression profiles in Spo11(-/ -)adult and juvenile wild-type testis to describe genes expressed before and after the meiotic arrest resulting from the knocking out of Spo11. These genes were characterized using the Gene Ontology data base. To focus on genes involved in meiosis, we performed comparative gene expression analysis of Spo11(-/ -)and wild-type testes from 15-day mice, when spermatocytes have just entered pachytene. We found that the knockout of Spo11 causes dramatic changes in the level of expression of genes that participate in meiotic recombination (Hop2, Brca2, Mnd1, FancG) and in the meiotic checkpoint (cyclin B2, Cks2), but does not affect genes encoding protein components of the synaptonemal complex. Finally, we discovered unknown genes that are affected by the disruption of the Spo11 gene and therefore may be specifically involved in meiosis and spermatogenesis. 相似文献