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Volumn 74, Issue , 2013, Pages 33-56

Quantitative cw Overhauser effect dynamic nuclear polarization for the analysis of local water dynamics

Author keywords

Dynamic nuclear polarization; Hydration dynamics; Hydration water; NMR relaxometry; Overhauser

Indexed keywords

DYNAMICS; ELECTRON SPIN RESONANCE SPECTROSCOPY; HYDRATES; HYDRATION; PROBES; SPIN DYNAMICS; SPIN POLARIZATION; SPIN-LATTICE RELAXATION; TOOLS;

EID: 84890262720     PISSN: 00796565     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.pnmrs.2013.06.001     Document Type: Review
Times cited : (113)

References (108)
  • 23
    • 84891901174 scopus 로고    scopus 로고
    • note
    • In practical application, the relevant (microwave and radio) frequencies can be measured more accurately than one can measure the absolute value of the static field with a Hall probe.
  • 25
    • 84891900853 scopus 로고    scopus 로고
    • note
    • 1 - E gives the polarization transferred in units of thermal polarization of the proton.
  • 26
    • 84891901190 scopus 로고    scopus 로고
    • note
    • i.e. Induced by dipolar interaction with the electron spin.
  • 48
    • 84891903490 scopus 로고    scopus 로고
    • note
    • Indeed, for isotropic models, d is typically termed the "distance of closest approach." However, in practical experiments, as shown by the work of Bryant and coworkers [72,19],it is standard practice to fit data for a non-isotropic system to an isotropic model, such as the FFHS model. In such a situation, it does not seem physically realistic that d actually represents the closest approach between the spin label and the water, as the typical phrasing would imply; rather d is, at best, a type of weighted average of the different closest approaches at different solid angles. Indeed, the FCR experiments of Bryant and coworkers do see a measurable change of the fit value of d in response to changes, e.g. changes in temperature, that would not seem physically capable of changing the distance of closest approach between the spin label and the water.
  • 49
    • 84891902001 scopus 로고    scopus 로고
    • note
    • c is a functional of both the molecular trajectories and the form of the interaction used to probe those trajectories (in this work, the magnetic dipolar interaction), as it is specifically determined by the lifetime of the autocorrelation function for the interaction.
  • 59
    • 84891903038 scopus 로고    scopus 로고
    • note
    • -1].
  • 88
    • 84891901140 scopus 로고    scopus 로고
    • note
    • 1,j, as the model is in the extreme narrowing limit.
  • 89
    • 84891901624 scopus 로고    scopus 로고
    • note
    • 1 experiment (as in the full inversion or saturation recovery experiment).
  • 91
    • 84891902614 scopus 로고    scopus 로고
    • note
    • 1,HH as 0.
  • 94
    • 84891901996 scopus 로고    scopus 로고
    • note
    • More technical specifications for this probe will be introduced in a future publication: [95].
  • 96
    • 84891903021 scopus 로고    scopus 로고
    • note
    • 1 field per unit power, of the new "pass through probe" is the same or greater than that of the older "open bottom probe" and greater than that of the commercial ENDOR probe.
  • 97
    • 84891901553 scopus 로고    scopus 로고
    • note
    • However, we also caution that while the modes of sample motion that describe the motion of water near the nitroxide are likely equilibrated with the dielectrically excited modes of the bulk water, to the best of our knowledge, it has not yet been proven whether or not such an equilibration should take place under the experimental situation relevant to ODNP. This is especially true since the sample resides in a small capillary tube, where the bulk water that interacts with the capillary is continuously cooled, while the timescales associated with the exchange and heat transfer between the bulk water and the hydration water are unknown.
  • 98
    • 84891903713 scopus 로고    scopus 로고
    • note
    • The typical covariance analysis of the asymptotic data becomes unusually complicated as a result of the fact that the correlation of the uncertainty between enhancement measurements is very high as a result of the normalization procedure. The development of a method to automatically process such data and compute such errors is currently underway.
  • 108
    • 84891902138 scopus 로고    scopus 로고
    • note
    • ρ is calculated from the denominator on the right side of Eq. (23).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.