Author
Jin Hyung Lee
Other affiliations: University of California, Los Angeles, University of California, Rutgers University
Bio: Jin Hyung Lee is an academic researcher from Stanford University. The author has contributed to research in topics: Optogenetics & Population. The author has an hindex of 26, co-authored 71 publications receiving 3633 citations. Previous affiliations of Jin Hyung Lee include University of California, Los Angeles & University of California.
Papers published on a yearly basis
Papers
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TL;DR: The results suggest that the activity responsible for the formation of asymmetric dimethylated arginine residues in Sm proteins is either PRMT5 or a protein associated with it in the immunoprecipitated complex.
44 citations
Patent•
27 Jan 2016TL;DR: In this paper, a target neural cell population in the first region of a brain was modified to express light-responsive molecules using a light pulse, and the light responsive molecules in the target neural cells population were stimulated.
Abstract: Disclosed herein are systems and methods involving the use of magnetic resonance imaging and optogenetic neural stimulation. Aspects of the disclosure include modifying a target neural cell population in a first region of a brain to express light-responsive molecules. Using a light pulse, the light-responsive molecules in the target neural cell population are stimulated. Multiple regions of the brain are scanned via magnetic resonance imaging. The scans allow for observation of a neural reaction in response to the stimulation in at least one of the multiple regions of the brain.
42 citations
TL;DR: A novel compressed sensing high spatial resolution functional MRI (fMRI) method and the advantages and limitations of using CS for high spatialresolution fMRI are demonstrated.
Abstract: Purpose
To propose a novel compressed sensing (CS) high spatial resolution functional MRI (fMRI) method and demonstrate the advantages and limitations of using CS for high spatial resolution fMRI.
Methods
A randomly undersampled variable density spiral trajectory enabling an acceleration factor of 5.3 was designed with a balanced steady state free precession sequence to achieve high spatial resolution data acquisition. A modified k-t SPARSE method was then implemented and applied with a strategy to optimize regularization parameters for consistent, high quality CS reconstruction.
Results
The proposed method improves spatial resolution by six-fold with 12 to 47% contrast-to-noise ratio (CNR), 33 to 117% F-value improvement and maintains the same temporal resolution. It also achieves high sensitivity of 69 to 99% compared the original ground-truth, small false positive rate of less than 0.05 and low hemodynamic response function distortion across a wide range of CNRs. The proposed method is robust to physiological noise and enables detection of layer-specific activities in vivo, which cannot be resolved using the highest spatial resolution Nyquist acquisition.
Conclusion
The proposed method enables high spatial resolution fMRI that can resolve layer-specific brain activity and demonstrates the significant improvement that CS can bring to high spatial resolution fMRI. Magn Reson Med 76:440–455, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
40 citations
TL;DR: MR imaging shows promise for in vivo measurement of EF and glomerular filtration rate, which may be useful in assessing the clinical importance of renal arterial stenosis.
Abstract: PURPOSE: To test whether magnetic resonance (MR) imaging enables accurate measurement of extraction fraction (EF) in swine with unilateral renal ischemia and to evaluate effects of renal arterial stenosis on EF and single-kidney glomerular filtration rate. MATERIALS AND METHODS: High-grade unilateral renal arterial stenoses were surgically created in eight pigs. Direct measurements of renal venous and arterial inulin concentration provided reference standard estimates of single-kidney EF. Pigs were imaged with a 1.5-T imager to estimate EF, renal blood flow, and glomerular filtration rate. A breath-hold inversion-recovery spiral sequence was used to measure T1 of blood in the infrarenal inferior vena cava and renal veins after intravenous administration of gadopentetate dimeglumine, and these data were used to calculate EF. Cine-phase contrast material–enhanced imaging of the renal arteries provided quantitative renal blood flow measurements. Bilateral single-kidney glomerular filtration rate was then det...
38 citations
Patent•
16 Oct 2007TL;DR: In this paper, the nanocrystals comprising metals and metal alloys, which are formed by a process that results in a layer of graphite in direct contact with the metallic core, are used in vivo as MRI contrast agents, X-ray contrast agents and near IR heating agents, drug delivery, protein separation, catalysis etc.
Abstract: Disclosed are nanocrystals comprising metals and metal alloys, which are formed by a process that results in a layer of graphite in direct contact with the metallic core. The nanocrystals may be used in vivo as MRI contrast agents, X-ray contrast agents, near IR (NIR) heating agents, drug delivery, protein separation, catalysis etc. The nanocrystals may be further functionalized with a hydrophilic coating, e.g., phospholipid-polyethylene glycol, which improves in vivo stability. The process comprises chemical vapor deposition of metals adsorbed onto silica as a fine powder, in conjunction with a carbon containing gas, which coats the metal particles. The silica is then etched away. Preferred metals include iron, gold, cobalt, platinum, ruthenium and mixtures thereof, e.g., FeCo and AuFe. The process permits control of the alloy compositions, size, and other characteristics.
34 citations
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TL;DR: In this paper, the authors proposed a passive targeting mechanism, active targeting strategies using ligands or antibodies directed against selected tumor targets amplify the specificity of these therapeutic nanoparticles, enabling them to carry their loaded active drugs to cancer cells by selectively using the unique pathophysiology of tumors.
Abstract: Cancer nanotherapeutics are rapidly progressing and are being implemented to solve several limitations of conventional drug delivery systems such as nonspecific biodistribution and targeting, lack of water solubility, poor oral bioavailability, and low therapeutic indices. To improve the biodistribution of cancer drugs, nanoparticles have been designed for optimal size and surface characteristics to increase their circulation time in the bloodstream. They are also able to carry their loaded active drugs to cancer cells by selectively using the unique pathophysiology of tumors, such as their enhanced permeability and retention effect and the tumor microenvironment. In addition to this passive targeting mechanism, active targeting strategies using ligands or antibodies directed against selected tumor targets amplify the specificity of these therapeutic nanoparticles. Drug resistance, another obstacle that impedes the efficacy of both molecularly targeted and conventional chemotherapeutic agents, might also be overcome, or at least reduced, using nanoparticles. Nanoparticles have the ability to accumulate in cells without being recognized by P-glycoprotein, one of the main mediators of multidrug resistance, resulting in the increased intracellular concentration of drugs. Multifunctional and multiplex nanoparticles are now being actively investigated and are on the horizon as the next generation of nanoparticles, facilitating personalized and tailored cancer treatment.
2,558 citations
TL;DR: A background on applications of MNPs as MR imaging contrast agents and as carriers for drug delivery and an overview of the recent developments in this area of research are provided.
2,295 citations
Journal Article•
TL;DR: Multifunctional and multiplex nanoparticles are now being actively investigated and are on the horizon as the next generation of nanoparticles, facilitating personalized and tailored cancer treatment.
2,217 citations
TL;DR: The authors emphasize on an intuitive understanding of CS by describing the CS reconstruction as a process of interference cancellation, and there is also an emphasis on the understanding of the driving factors in applications.
Abstract: This article reviews the requirements for successful compressed sensing (CS), describes their natural fit to MRI, and gives examples of four interesting applications of CS in MRI. The authors emphasize on an intuitive understanding of CS by describing the CS reconstruction as a process of interference cancellation. There is also an emphasis on the understanding of the driving factors in applications, including limitations imposed by MRI hardware, by the characteristics of different types of images, and by clinical concerns.
2,134 citations
TL;DR: A primer on the application of optogenetics in neuroscience is provided, focusing on the single-component tools and highlighting important problems, challenges, and technical considerations.
1,712 citations