471 research outputs found
Synthesis of nitroxyl radical by direct nucleophilic functionalization of a C-H bond in the azadiene systems
Cyclic dinitrones underwent nucleophilic substitution of the hydrogen atom in the reaction with a paramagnetic carbanion, the lithium derivative of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide, to give polyfunctional nitronyl nitroxyls. © 2012 Springer Science+Business Media New York
Recommended from our members
Genome-wide de Novo Prediction of Proximal and Distal Tissue-Specific Enhancers
Determining how transcriptional regulatory networks are encoded in the human genome is essential for understanding how cellular processes are directed. Here, we present a novel approach for systematically predicting tissue specific regulatory elements (REs) that blends genome-wide expression profiling, vertebrate genome comparisons, and pattern analysis of transcription factor binding sites. This analysis yields 4,670 candidate REs in the human genome with distinct tissue specificities, the majority of which reside far away from transcription start sites. We identify key transcription factors (TFs) for 34 distinct tissues and demonstrate that tissue-specific gene expression relies on multiple regulatory pathways employing similar, but different cohorts of interacting TFs. The methods and results we describe provide a global view of tissue specific gene regulation in humans, and propose a strategy for deciphering the transcriptional regulatory code in eukaryotes
The use of CCCM for the creation of the high-temperature detectors of the water wapor
A technique for assessing the presence of water vapor in a mixture using high-temperature detectors made of carbon-carbon composite material (CCCM) is proposed. The change in the electrical resistance of CCCM in a mixture containing water vapor at a temperature of 1000 °C is presented. The efficiency of such detectors has been tested and experimentally confirmed.Запропоновано методику оцінки появи водяної пари в составі суміші із використанням високотемпературних детекторів із вуглець-вуглецевого композиційного матеріалу (ВВКМ). Проведено дослідження зміни електричного опору ВВКМ у суміші, що містить водяну пару при температурі 1000 °С. Перевірено та експериментально підтверджено ефективність таких детекторів
New approach to synthesis of nitronyl and imino nitroxides based on SNH methodology
It is shown that SN H approach opens new possibilities in the synthesis of polyfunctional nitronyl and imino nitroxides. It is found that the interaction of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1- oxyl lithium salt Li1 with 3,6-diaryl-1,2,4-triazines leads to formation of the corresponding triazines bearing nitronyl nitroxide or imino nitroxide substituent at position 5 of the heterocycle. The reaction of Li1 with pyridazine-N-oxide gives rise to nitroxide with buten-3-ynyl substituent 5. Spin-labeled 5 could be readily transformed by the use of 1,3-dipolar and nucleophilic addition reactions, as well as oxidative coupling, that gives a large group of new paramagnets: 2-(1H-pyrazol-5-yl)vinyl-, 2-ethynylcyclopropyl- , 2-(3-(ethoxycarbonyl) isoxazol-5-yl)vinyl-, 1-(pyrrolidin-1-yl)but-3-ynyl- substituted nitronyl nitroxide and a diradical - 2,2′-((1E,7E)-octa-1,7- dien-3,5-diyne-1,8-diyl)bis(4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide- 1-oxyl). The new nitroxides were characterized by X-ray single crystal data, ESR and static magnetic susceptibility measurements. © ARKAT USA, Inc
SILICON MONOCRYSTALS FOR ALTERNATIVE ENERGY
This paper considers features of the formation and microstructure revealing of profound n- and p-type silicon monocrystals. Influence of hole and electron conductivity in semiconductors on the pattern of anodic etching is determined. Correlation among silicon microstructure, dislocation density and minority carriers’ lifetime has been studied. Influence of impurity diffusion from the surface into the space of the crystal on electrical properties’ changes of the semiconductor is shown
WHAT RESULTS IN TENDON AND MUSCLE TISSUES OF THE ROTATOR CUFF FROM FULL-THICKNESS TEARS: DATA OF MRI, ARTHROSCOPY AND HISTOLOGY
Full-thickness rotator cuff tears - is abundant injury which leads to the expressed pain syndrome and functional violation of the top extremity. At making decision about necessary of surgery, MRI is the important source of information about the injury The purpose: to determine the qualitative and quantitative indicators of degenerative-dystrophic changes in muscular and tendinous parts of the rotator cuff. based on a combined MRI, arthroscopic and histological diagnostics of full-thickness rupture of shoulder cuff Methods: We have examined 28 patients with full-thickness rotator cuff tears. MRI of damaged joint to all patients before an operation was performed. Thereafter an arthroscopy was performed and intraoperative biopsy of the muscular and tendinous parts of the rotator cuff, with following histological examination. Results: It was found that at small full-thickness rotator cuff tears the intensity of degenerative changes in muscular and tendinous tissue was lower, so these tears are the most promising for all kinds of treatment. At medium and big tears intensity of degenerative changes in the tissues begins to prevail over productive inflammation and it limits to the ability of conservative treatment and increases the risk of unsuccessful outcomes of arthroscopic reconstruction. Conclusions: In this regard, it is necessary to search biological decisions, which complement the stage of arthroscopic reconstruction of the rotator cuff
Phase field modelling voids nucleation and growth in binary systems
We present a comprehensive study of voids formation, nucleation and growth in
a prototype model of binary alloys subjected to irradiation by using a combined
approach based on phase field and rate theories. It is shown that voids
formation is caused by interaction of irradiation-produced vacancies through
elastic deformation of a lattice and vacancy coupling with composition field of
the alloy. Phase diagrams illustrating the formation of states related to solid
solution, phase decomposition, and patterning are obtained. Formation of voids
from supersaturated ensemble of vacancies is accompanied by composition
rearrangement of alloy components. It was found that elastic inhomogeneity
leading to the formation of anisotropic precipitates in an initially prepared
binary alloy results in the formation of a void super-lattice under
irradiation. It was shown that voids nucleate and grow with dose according to
diffusion controlled precipitation processes, where universal dynamics of voids
growth is revealed. Estimations of main quantitative and statistical
characteristics of voids by using material parameters relevant to most of
alloys and steels give good agreement with experimental observations.Comment: 21 pages, 10 figure
- …