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The feasibility of an orthogonal deprotection-conjugation protocol, holding the promise of libraries of functionally diverse chemical probes attached to cysteine-anchored peptide scaffolds, has been explored with a model system. The necessary tools for assembly of the hybrid libraries have been prepared and the tandem procedure optimized. S-alkylation and S-sulfenylation are featured as the chemoselective ligation reactions. [reaction: see text] 相似文献
23.
In this note we present a new proof of the quintuple product identity which is based on our study of order theta functions with characteristics and the identities they satisfy. In this context the quintuple product identity is another example of an identity which when phrased in terms of theta functions, rather than infinite products and sums, has a simpler form and is much less mysterious.
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Irwin I. Shapiro 《General Relativity and Gravitation》1972,3(1-2):135-148
Recent results from radar and radio gravity experiments are:
- Retardation of radar signals: 1.02 +?0.05 (planetary radar), 1.00 +? 0.04 (spacecraft);
- Deflection of radio waves: 0.99 +? 0.12 (short baseline interferometry), +0.15 1.04 (short baseline interferometry), ?0.10. 0.90 +? 0.05 (short baseline interferometry);
- Relativistic perihelion advance of Mercury: 0.99 +? 0.03 (planetary radar), 1.00 +? 0.01 (radar plus optical);
- Time variation of the gravitational constant: (G/G) < 4 ×10?10/yr (planetary radar). The first three results are expressed as fractions of the corresponding effects predicted by general relativity. In terms of the Eddington-Robertson parameters, the first two are approximately equal to (1+γ)/2 and the third to (2 + 2γ-β)/3. The third result depends on the assumption that the solar gravitational quadrupole moment vanishes; its effects cannot be separated usefully from those of general relativity with the present data set. The uncertainties are as given by the individual experimenters; in some cases they represent formal standard errors, in others an allowance for possible systematic errors is included.
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Four one-phonon Raman lines have been found in CdIn2S4 (ZnIn2S4) spinels at 92 (72) cm-1, 186 (184) cm-1, 246 (253) cm-1, and 367 (372) cm-1 for incident photon energies well below the energy gap EG ~ 2.4 (2.2) eV at 300 K. For photon energies close to EG, the 367 cm-1 mode underwent a resonant enhancement in CdIn2S4 and four infrared active but Raman forbidden F1u modes appeared in the CdIn2S4 and ZnIn2S4 Raman spectra: TO modes at 226 (221) cm-1 and 309 (312) cm-1, and LO modes at 274 (272) cm-1 and 340 (342) cm-1. 相似文献
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Irwin Kra 《Acta Mathematica》1981,146(1):231-270
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Albone DP Challenger S Derrick AM Fillery SM Irwin JL Parsons CM Takada H Taylor PC Wilson DJ 《Organic & biomolecular chemistry》2005,3(1):107-111
Amination of C-H bonds activated by ether oxygen atoms is facile with chloramine-T as nitrene source and copper(I) chloride in acetonitrile as catalyst. For cyclic ethers the hemiaminal products are generally stable and can be isolated pure. For acyclic ethers, the hemiaminal products, as expected, fragment with elimination of alcohol to yield imines. When activation of benzylic positions is remote through a conjugated system, stable benzylamine derivatives are isolated. Mechanistic studies are consistent with concerted insertion of an electrophilic nitrenoid into the C-H bond in the rate-determining step, though in an asynchronous manner with a more activated substrate. 相似文献
30.
Abusaidi R Akerib DS Barnes PD Bauer DA Bolozdynya A Brink PL Bunker R Cabrera B Caldwell DO Castle JP Clarke RM Colling P Crisler MB Cummings A Da Silva A Davies AK Dixon R Dougherty BL Driscoll D Eichblatt S Emes J Gaitskell RJ Golwala SR Hale D Haller EE Hellmig J Huber ME Irwin KD Jochum J Lipschultz FP Lu A Mandic V Martinis JM Nam SW Nelson H Neuhauser B Penn MJ Perera TA Perillo Isaac MC Pritychenko B Ross RR Saab T Sadoulet B Schnee RW Seitz DN Shestople P Shutt T Smith A Smith GW 《Physical review letters》2000,84(25):5699-5703
The Cryogenic Dark Matter Search (CDMS) employs Ge and Si detectors to search for weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. CDMS data, accounting for the neutron background, give limits on the spin-independent WIMP-nucleon elastic-scattering cross section that exclude unexplored parameter space above 10 GeV/c2 WIMP mass and, at >75% C.L., the entire 3sigma allowed region for the WIMP signal reported by the DAMA experiment. 相似文献