Category Archives: Book

Nitroxides: Brief History, Fundamentals, and Recent Developments #DNPNMR

Nitroxide-based radicals are essential to many DNP-NMR experiments and a profound understanding of their chemistry is essential to synthesize new polarizing agents with increased DNP performance. This book gives a comprehensive overview of nitroxides – a good introduction for the new comer but also a reference guide for the expert.

Likhtenshtein, Gertz I. Nitroxides: Brief History, Fundamentals, and Recent Developments. Springer Series in Materials Science. Springer International Publishing, 2020.

Written by a pioneer in the development of spin labeling in biophysics, this expert book covers the fundamentals of nitroxide spin labeling through cutting-edge applications in chemistry, physics, materials science, molecular biology, and biomedicine. Nitroxides have earned their place as one of the most popular organic paramagnets due to their suitability as inhibitors of oxidative processes, as a means to polarize magnetic nuclei, and, in molecular biology, as probes and labels to understand molecular structures and dynamics AS DRAGS FOR CANCER AND OTHER DISEASES. Beginning with an overview of the basic methodology and nitroxides’ 145-year history, this book equips students with necessary background and techniques to undertake original research and industry work in this growing field.

DNP Mechanisms #DNPNMR

Kundu, Krishnendu, Frédéric Mentink‐Vigier, Akiva Feintuch, and Shimon Vega. “DNP Mechanisms.” In EMagRes, 295–338. American Cancer Society, 2019.

This article presents a comprehensive description of the spin dynamics underlying the main DNP mechanisms leading to nuclear signal enhancements in glassy amorphous solids containing free radicals. The emphasis of the article to derive quantum mechanically based formalisms that enable us to analyze experimental DNP data. After a short review of the history of DNP, rate equations of the eigenstate populations of static coupled electron–nuclear spin systems are introduced, based on their spin-Hamiltonians and including spin-lattice and cross-relaxation mechanisms. They are used to simulate the dynamics of small spin systems under microwave (MW) irradiation and the basic Solid Effect (SE), Cross Effect (CE), and Overhauser DNP (O-DNP) enhancement mechanisms are presented. These calculations are then extended to systems containing up to 10 spins and are used to calculate EPR, ELDOR, and DNP spectra. Plots showing the population of the eigenstates vs energy are used to demonstrate the conditions for the thermal mixing mechanism and the corresponding EPR and ELDOR spectra are discussed. Following these calculations, the electron spectral diffusion (eSD) and the indirect Cross Effect (iCE) numerical models are introduced and used to analyze EPR and DNP spectra of real samples. In the last section, the basic theory of magic angle spinning (MAS) DNP on small spin systems is summarized and the influence of the rotor events on the quasiperiodic steady-state DNP enhancements discussed. The origins of depolarization effects occurring when no MW is applied are described. Finally, the nuclear spin diffusion process inside the diffusion barrier is studied using multielectron and multinuclear calculations.

Essentials of Dynamic Nuclear Polarization #DNPNMR

Dear Colleague,

It is my pleasure to announce that a limited edition of 

    `Essentials of Dynamic Nuclear Polarization’ 

is now available at the UK branch of Amazon:

This book is a concise introduction to dynamic nuclear polarization. 

It presents the foundations of the solid effect, Provotorov’s theory,

thermal mixing and the cross effect, and includes some of the latest 

developments, such as the integrated solid effect.  It condenses half 

a century of personal experience in the field, and is oriented towards 

graduate students, researchers and anyone with a working knowledge 

of the quantum mechanics of spin.  

The summer school on `The principles of dynamic nuclear polarization’ 

in Tramelan, Switzerland, from 22 to 26 August, will be based on this book

and participants will receive a complementary copy at the school.  

For further information please consult:

Additional material will eventually be posted on my website:

Yours sincerely,

Tom Wenckebach

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