| Thermal Synthesis of Perchlorinated Oligosilanes: A Fresh Look at an Old Reaction
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| A combined experimental and theoretical study of the high-temperature reaction of SiCl4 and elemental silicon is presented. The nature and reactivity of the product formed upon rapid cooling of the gaseous reaction mixture is investigated by comparison with defined model compounds, i.e. cyclo-Si5Cl10, n-Si5Cl12 and n-Si4Cl10. A DFT assessment provides mechanistic insight into the oligosilane formation. Experimental 29Si NMR investigations, supported by quantum-chemical 29Si NMR calculations, consistently show that the reaction product is composed of discrete molecular perchlorinated oligosilanes. Low-temperature chlorination is an unexpectedly selective means for the transformation of cyclosilanes to acyclic species by endocyclic Si-Si bond cleavage, and we provide a mechanistic rationalization for this observation. In contrast to the raw material, the product obtained after low-temperature chlorination represents an efficient source of neo-Si5Cl12 or the amine-stabilized disilene EtMe2N*SiCl2Si(SiCl3)2 ...
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| Mars rover Opportunity on walkabout near crater rim
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 Pasadena CA (JPL) Jun 26, 2017 NASA's senior Mars rover, Opportunity, is examining rocks at the edge of Endeavour Crater for signs that they may have been either transported by a flood or eroded in place by wind. Those scenarios are among the possible explanations rover-team scientists are considering for features seen just outside the crater rim's crest above "Perseverance Valley," which is carved into the inner slope
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| Rare US total solar eclipse excites Americans coast-to-coast
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 Washington (AFP) June 22, 2017 For the first time in almost a century the United States is preparing for a coast-to-coast solar eclipse, a rare celestial event millions of Americans, with caution, will be able to observe. During the eclipse on August 21 - the first of its kind since 1918 - the moon will pass between the sun and Earth, casting a dark shadow and making visible the sun's normally obscured atmosphere, or so
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| ArianeGroup signs contract with ESA to develop Prometheus engine
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 Paris (SPX) Jun 26, 2017 The European Space Agency and Airbus Safran Launchers, the 50/50 joint-venture set up by the Airbus and Safran groups, which will become ArianeGroup on July 1, have signed, at the Paris Air Show, the first tranche of the development contract for the future Prometheus LOx-methane engine. "This signing underlines our determination to prepare now for the future of Europe's launchers beyond 20
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| N.Korea conducts rocket engine test: US official
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 Seoul (AFP) June 23, 2017 North Korea has tested a rocket engine that could be fitted to an intercontinental ballistic missile, a US official said, in an apparent provocation ahead of a summit between President Donald Trump and the leader of South Korea. President Moon Jae-In heads to Washington next week to meet Trump for the first time since taking office in May, as tensions soar on the Korean peninsula over Kim Jo
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| Eclipse Expectations Excite Escapades for Enlightenment
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 Los Angeles, CA (SPX) Jun 26, 2017 First reported by Spacedaily.com on December 20, 2016, the great American eclipse has been a daily occupation for my mind and wallet. Hours and hours have been spent with this NASA Total Solar Eclipse Interactive Map. Of course, Expedia played an important role in ruling out locations. Idaho? Forget about it. Oregon. Oh Oregon. I explored the trails of Oregon more that Lewis and Clark to find th
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| Test of US-Japanese missile interceptor fails
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 Washington (AFP) June 22, 2017 The US Navy and the Japanese ministry of defense have unsuccessfully attempted to intercept a ballistic missile in a test of a jointly built system off Hawaii, the US military said Wednesday. The two nations have been working together since 2006 to develop a variant of the Standard Missile-3, a ship-launched missile that operates as part of the Aegis Ballistic Missile Defense System. Tue
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| Metal Ions Activated DNAzymes Used for Regulation of Telomerase Activity in Living Cells
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| Telomerase is a key regulator in cell metabolism, tissue renewal and organismal lifespan. Here we develop a simple strategy to modulate cellular telomerase activity, and further control cell fate based on Mg2+ and Zn2+ activated DNAzymes in living cells. Through modulation of telomerase activity, we can regulate cell behavior, including cell migration, cell differentiation, cell senescence and cell cycle. Our work provides a new way to modulate telomerase activity in living cells by using DNAzymes.
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, article language English ( Russian [ translation ] )
