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51.
Terence Davis Matthew C Dix Michal J Rokicki Amy JC Brook Caroline S Widdowson David Kipling Mark C Bagley 《Chemistry Central journal》2011,5(1):1-5
To develop more potent small molecules with enhanced free radical scavenger properties, a series of N-substituted isatin derivatives was synthesized, and the cytoprotective effect on the apoptosis of PC12 cells induced by H2O2 was screened. All these compounds were found to be active, and N-ethyl isatin was found with the most potent activity of 69.7% protective effect on PC12 cells. Structure-activity relationship analyses showed the bioactivity of N-alkyl isatins decline as the increasing of the chain of the alkyl group, furthermore odd-even effect was found in the activity, which is interesting for further investigation. 相似文献
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53.
The relative rates of H-transfer between partners in ion-neutral complexes were compared with those in intramolecular rearrangements using results of first differential photoionization mass spectrometry measurements. Complex-mediated H-transfers are inferred to have rates of the same order as those for intramolecular hydrogen rearrangements, suggesting a similar range of motion of the reactive sites in both types of reactions. It is also concluded that at their fastest H-transfers take place between the partners in ion-neutral complexes within at most the time of several rotations of the partners in the complexes. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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55.
We present an exact calculation of the total cross section πtot of theZ 0 production ine ?1+p→e ?+Z 0+X processes. We find a total cross section πtot?1.0·10?36cm2 for an energy in the center of mass of 300 GeV and aZ 0 mass of 90GeV, which is quite a measurable result in somee ?1 proton collider experiments, like HERA or SPS/LEP. 相似文献
56.
Hannu?TiitinenEmail author Anna?Mari?M?kel? Ville?M?kinen Patrick?JC?May Paavo?Alku 《BMC neuroscience》2005,6(1):62
Background
The cortical activity underlying the perception of vowel identity has typically been addressed by manipulating the first and second formant frequency (F1 & F2) of the speech stimuli. These two values, originating from articulation, are already sufficient for the phonetic characterization of vowel category. In the present study, we investigated how the spectral cues caused by articulation are reflected in cortical speech processing when combined with phonation, the other major part of speech production manifested as the fundamental frequency (F0) and its harmonic integer multiples. To study the combined effects of articulation and phonation we presented vowels with either high (/a/) or low (/u/) formant frequencies which were driven by three different types of excitation: a natural periodic pulseform reflecting the vibration of the vocal folds, an aperiodic noise excitation, or a tonal waveform. The auditory N1m response was recorded with whole-head magnetoencephalography (MEG) from ten human subjects in order to resolve whether brain events reflecting articulation and phonation are specific to the left or right hemisphere of the human brain. 相似文献57.
J. C. Wallet E. M. Gaydou E. Espinosa O. Osorno E. Molins C. Miravitlles 《Journal of chemical crystallography》1993,23(4):297-300
C17H14O4,M
r
=282.3, triclinic,P-1,a=8.469(3),b=8.516(2),c=20.425(8)Å,=84.95(3),=81.98(3), =70.47(2)°,V=1373(13)Å3,Z=4,D
x
=1.365 g cm–3, (MoK
)=0.71069 Å,=0.91 cm–1,F(000)=592,T=294K,R=0.038 for 3577 observed reflections (F>3 (F)). The asymmetric unit is composed of two molecules. These two molecules, which are in planar conformations, differ in 4-methoxyl group orientation. Short intramolecular contacts are found between the -benzopyran portion and the dimethoxyphenyl ring. 相似文献
58.
J. C. Wallet 《Zeitschrift fur Physik C Particles and Fields》1986,30(4):575-584
We study the effects of an anomalous (non standard model) electric quadrupole moment λ for theW on the process \(p\bar p \to W^ - \gamma X\) and compare them to those obtained with theW anomalous (non standard model) electric dipole moment (κ). Such aW elèctric quadrupole moment λ is allowed by the most general γWW vertex compatible withC, P, T invariance and electromagnetic current conservation. We find that values of λ?0.5 could produce large departures from the predictions of the standard model which may be observable at the FNALp \(\bar p\) collider. 相似文献
59.
Blewitt G LoSecco JM Bionta RM Bratton CB Casper D Chrysicopoulou P Claus R Cortez BG Errede S Foster GW Gajewski W Ganezer KS Goldhaber M Haines TJ Jones TW Kielczewska D Kropp WR Learned JG Lehmann E Park HS Reines F Schultz J Seidel S Shumard E Sinclair D Sobel HW Stone JL Sulak L Svoboda R van der Velde JC Wuest C 《Physical review letters》1985,55(20):2114-2117
60.