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Materials Chemistry

Articles 1 - 7 of 7

Full-Text Articles in Physics

Hyperpolarization Of Silicon Nanoparticles With Tempo Radicals, Jingzhe Hu, Nicholas Whiting, Pratip Bhattacharya Mar 2018

Hyperpolarization Of Silicon Nanoparticles With Tempo Radicals, Jingzhe Hu, Nicholas Whiting, Pratip Bhattacharya

Nicholas Whiting

Silicon-based particles can be hyperpolarized via dynamic nuclear polarization to enhance 29Si magnetic resonance signals. Application of this technique to nanoscale silicon particles has been limited because of the low signal enhancements achieved; it is hypothesized that this is due to the low number of endogenous electronic defects inherent to the particles. We introduce a method of incorporating exogenous radicals into silicon nanoparticle suspensions in order to improve the hyperpolarization of 29Si nuclear spins to levels sufficient for in vivo MR imaging. Calibration of radical concentrations and polarization times are reported for a variety of silicon particle sizes (30−200 nm …

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Hyperpolarized Porous Silicon Nanoparticles: Potential Theragnostic Material For 29si Magnetic Resonance Imaging, Hyeonglim Seo, Ikjang Choi, Nicholas Whiting, Jingzhe Hu, Quy S. Luu, Shivanand Pudakalakatti, Caitlin Mccowan, Yaewon Kim, Niki Zacharias Millward, Seunghyun Lee, Pratip Bhattacharya, Youngbok Lee Dec 2017

Hyperpolarized Porous Silicon Nanoparticles: Potential Theragnostic Material For 29si Magnetic Resonance Imaging, Hyeonglim Seo, Ikjang Choi, Nicholas Whiting, Jingzhe Hu, Quy S. Luu, Shivanand Pudakalakatti, Caitlin Mccowan, Yaewon Kim, Niki Zacharias Millward, Seunghyun Lee, Pratip Bhattacharya, Youngbok Lee

Nicholas Whiting

Porous silicon nanoparticles have recently garnered attention as potentially-promising biomedical platforms for drug delivery and medical diagnostics. Here, we demonstrate porous silicon nanoparticles as contrast agents for 29Si magnetic resonance imaging. Size-controlled porous silicon nanoparticles were synthesized by magnesiothermic reduction of silica nanoparticles and were surface activated for further functionalization. Particles were hyperpolarized via dynamic nuclear polarization to enhance their 29Si MR signals; the particles demonstrated long 29Si spin-lattice relaxation (T1) times (~25 mins), which suggests potential applicability for medical imaging. Furthermore, 29Si hyperpolarization levels were sufficient to allow 29Si MRI in phantoms. These results underscore the potential of porous …

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Hyperpolarization Methods For Mrs, Boyd M. Goodson, Nicholas Whiting, Aaron M. Coffey, Panayiotis Nikolaou, Fan Shi, Brogan M. Gust, Maxwell E. Gemeinhardt, Roman Shchepin, Jason G. Skinner, Jonathan R. Birchall, Michael J. Barlow, Eduard Y. Chekmenev Dec 2014

Hyperpolarization Methods For Mrs, Boyd M. Goodson, Nicholas Whiting, Aaron M. Coffey, Panayiotis Nikolaou, Fan Shi, Brogan M. Gust, Maxwell E. Gemeinhardt, Roman Shchepin, Jason G. Skinner, Jonathan R. Birchall, Michael J. Barlow, Eduard Y. Chekmenev

Nicholas Whiting

This article covers the fundamental principles and practice of NMR hyperpolarization techniques, which are proving useful for in vivo magnetic resonance spectroscopy (MRS) studies of metabolism in animal models, and clinical trials with hyper-enhanced sensitivity. Fundamentally, hyperpolarization methods enhance nuclear spin polarization by orders-of-magnitude, resulting in concomitant improvement in NMR detection sensitivity. The hyperpolarization methods described here – dynamic nuclear polarization (DNP), para-hydrogen induced polarization (PHIP), signal amplification by reversible exchange (SABRE), and spin-exchange optical pumping (SEOP) – are capable of achieving nuclear spin polarization approaching the theoretical maximum of unity on nuclear spin sites of molecular or atomic agents …

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Atomistic Simulations Of The Fusion-Plasma Material Interface, Mostafa Jon Dadras Jul 2014

Atomistic Simulations Of The Fusion-Plasma Material Interface, Mostafa Jon Dadras

Jonny Dadras

A key issue for the successful performance of current and future fusion reactors is understanding chemical and physical processes at the Plasma Material Interface (PMI). The material surfaces may be bombarded by plasma particles in a range of impact energies (1 eV - a few keV) and kept at a range of temperatures (300 - 1000 K). The dominant processes at the PMI are reflection and retention of impacting particles and sputtering (chemical and physical). Sputtering leads to surface erosion and pollution of the plasma, both of which degrade reactor performance. Retention influences the recycling of the plasma, and in …

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Solvent Dependency Of Azobenzene Thermal Relaxation, Chris Corkery, Alexis Goulet-Hanssens, Janet R. Belliveau, Mark Cronin-Golomb, Christopher J. Barrett Apr 2014

Solvent Dependency Of Azobenzene Thermal Relaxation, Chris Corkery, Alexis Goulet-Hanssens, Janet R. Belliveau, Mark Cronin-Golomb, Christopher J. Barrett

Chris Corkery

No abstract provided.

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Determination Of Plasma Parameters In A Dc Arcjet Part Ii, Scott Reeve, Wayne Weimer Dec 1994

Determination Of Plasma Parameters In A Dc Arcjet Part Ii, Scott Reeve, Wayne Weimer

Scott Reeve

No abstract provided.

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Determination Of Plasma Parameters In A Dc Arcjet Diamond Reactor: Part 1, Scott Reeve, Wayne Weimer Dec 1993

Determination Of Plasma Parameters In A Dc Arcjet Diamond Reactor: Part 1, Scott Reeve, Wayne Weimer

Scott Reeve

No abstract provided.

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