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排序方式: 共有912条查询结果,搜索用时 15 毫秒
901.
Thy Truong Kei G. I. Webber S. Madisyn Johnston Hannah Boekweg Caleb M. Lindgren Yiran Liang Alissia Nydegger Xiaofeng Xie Tsz-Ming Tsang D. A. Dasun N. Jayatunge Joshua L. Andersen Samuel H. Payne Ryan T. Kelly 《Angewandte Chemie (International ed. in English)》2023,62(34):e202303415
We combined efficient sample preparation and ultra-low-flow liquid chromatography with a newly developed data acquisition and analysis scheme termed wide window acquisition (WWA) to quantify >3,000 proteins from single cells in rapid label-free analyses. WWA employs large isolation windows to intentionally co-isolate and co-fragment adjacent precursors along with the selected precursor. Optimized WWA increased the number of MS2-identified proteins by ≈40 % relative to standard data-dependent acquisition. For a 40-min LC gradient operated at ≈15 nL/min, we identified an average of 3,524 proteins per single-cell-sized aliquot of protein digest. Reducing the active gradient to 20 min resulted in a modest 10 % decrease in proteome coverage. Using this platform, we compared protein expression between single HeLa cells having an essential autophagy gene, atg9a, knocked out, with their isogenic WT parental line. Similar proteome coverage was observed, and 268 proteins were significantly up- or downregulated. Protein upregulation primarily related to innate immunity, vesicle trafficking and protein degradation. 相似文献
902.
Brandon Johnston Daniel M. Loh Daniel G. Nocera 《Angewandte Chemie (International ed. in English)》2023,62(49):e202312128
Electrochemical approaches to form C(sp2)−C(sp3) bonds have focused on coupling C(sp3) electrophiles that form stabilized carbon-centered radicals upon reduction or oxidation. Whereas alkyl bromides are desirable C(sp3) coupling partners owing to their availability and cost-effectiveness, their tendency to undergo radical-radical homocoupling makes them challenging substrates for electroreductive cross-coupling. Herein, we disclose a metal-free regioselective cross-coupling of 1,4-dicyanobenzene, a useful precursor to aromatic nitriles, and alkyl bromides. Alkyl bromide reduction is mediated directly by 1,4-dicyanobenzene radical anions, leading to negligible homocoupling and high cross-selectivity to form 1,4-alkyl cyanobenzenes. The cross-coupling scheme is compatible with oxidatively sensitive and acidic functional groups such as amines and alcohols, which have proven difficult to incorporate in alternative electrochemical approaches using carboxylic acids as C(sp3) precursors. 相似文献
903.
Raman and resonance-Raman spectra of the I?3 ion isolated within CsI crystals have been studied using 647 nm and 488 nm exciting radiation. Sample temperatures between 300 and 20 K have been used. Eleven overtones of the symmetric stretching mode (nν1) have been observed in the resonance-Raman spectrum excited by the 488 nm Ar+ laser line. Bands centred at 153, 170, 264 and 304 cm?1 have been assigned as ν3, 2ν2, ν1+ν3 and 2ν3(Σ+) respectively. The remaining structure between the nν1 lines has been assigned as due to combinations of these lines with the lattice vibrations of the CsI crystal. 相似文献
904.
David C. Johnston 《Solid State Communications》1982,43(7):533-536
A universal correlation is reported between the magnetic susceptibility of the TaS2 layers at 300 K and the population (1 to 2 e-/TaS2) of the TaS2 conduction d-band in intercalation compounds of 2H-TaS2. From this curve, the variation in the density of states at the Fermi level D(EF) with EF was derived; good agreement with the variation predicted by band structure calculations for 2H-TaS2 was found. 相似文献
905.
J. C. Sarker L. H. Johnston R. L. Bhattacharjee G. R. Sudhakaran 《International Journal of Infrared and Millimeter Waves》1991,12(5):473-480
The Far Infrared (FIR) laser Stark spectrum ofSO
2 was investigated using the 337 m line of the HCN laser. Two distinct families, one originating at low field and the other at high field, were observed. The high field transition is identified as theJ
K–1,K+1=225,17214,18, v2=1 transition. A significant fourth-order Stark shift was observed for this transition in the presence of a large second-order Stark shift. The zero-field frequency of the assigned transition was obtained by accounting for the fourth-order contribution.Present Adress: Department of Chemistry, University of Rochester, Rochester, NY 14627. 相似文献
906.
We study a class of arrangements of lines with multiplicities on the plane which admit the Chalykh–Veselov Baker–Akhiezer function. These arrangements are obtained by adding multiplicity one lines in an invariant way to any dihedral arrangement with invariant multiplicities. We describe all the Baker–Akhiezer arrangements when at most one line has multiplicity higher than 1. We study associated algebras of quasi-invariants which are isomorphic to the commutative algebras of quantum integrals for the generalized Calogero–Moser operators. We compute the Hilbert series of these algebras and we conclude that the algebras are Gorenstein. We also show that there are no other arrangements with Gorenstein algebras of quasi-invariants when at most one line has multiplicity bigger than 1. 相似文献
907.
Keith Johnston Cecilia Tapia-Siles Bjoern Gerold Michiel Postema Sandy Cochran Alfred Cuschieri Paul Prentice 《Ultrasonics》2014
Single clouds of cavitation bubbles, driven by 254 kHz focused ultrasound at pressure amplitudes in the range of 0.48–1.22 MPa, have been observed via high-speed shadowgraphic imaging at 1 × 106 frames per second. Clouds underwent repetitive growth, oscillation and collapse (GOC) cycles, with shock-waves emitted periodically at the instant of collapse during each cycle. The frequency of cloud collapse, and coincident shock-emission, was primarily dependent on the intensity of the focused ultrasound driving the activity. The lowest peak-to-peak pressure amplitude of 0.48 MPa generated shock-waves with an average period of 7.9 ± 0.5 μs, corresponding to a frequency of f0/2, half-harmonic to the fundamental driving. Increasing the intensity gave rise to GOC cycles and shock-emission periods of 11.8 ± 0.3, 15.8 ± 0.3, 19.8 ± 0.2 μs, at pressure amplitudes of 0.64, 0.92 and 1.22 MPa, corresponding to the higher-order subharmonics of f0/3, f0/4 and f0/5, respectively. Parallel passive acoustic detection, filtered for the fundamental driving, revealed features that correlated temporally to the shock-emissions observed via high-speed imaging, p(two-tailed) < 0.01 (r = 0.996, taken over all data). Subtracting the isolated acoustic shock profiles from the raw signal collected from the detector, demonstrated the removal of subharmonic spectral peaks, in the frequency domain. The larger cavitation clouds (>200 μm diameter, at maximum inflation), that developed under insonations of peak-to-peak pressure amplitudes >1.0 MPa, emitted shock-waves with two or more fronts suggesting non-uniform collapse of the cloud. The observations indicate that periodic shock-emissions from acoustically driven cavitation clouds provide a source for the cavitation subharmonic signal, and that shock structure may be used to study intra-cloud dynamics at sub-microsecond timescales. 相似文献
908.
909.
910.
D. Naidoo H. P. Gunnlaugsson T. E. Mølholt R. Mantovan H. Masenda K. Bharuth-Ram K. Johnston H. P. Gislason G. Langouche S. Ólafsson G. Weyer R. Sielemann 《Hyperfine Interactions》2013,215(1-3):45-51
We review the state-of-the-art status of the research on the phase diagram of QCD matter out of quarks and gluons. Our discussions particularly include the extreme environments such as the high temperature, the high baryon density, and the strong magnetic field. 相似文献