Filters








42,337 Hits in 5.3 sec

Digital integral cloaking

Joseph S. Choi, John C. Howell
2016 Optica  
For our setup (Fig. 2) , the input scan required 29 s, and the computational processing required 22 s on the laptop that ran our code.  ...  For example, the horizontal scan distance required is (W s 2L tanFOV l ∕2). Here, W s is the active screen width of the output display, and FOV l is the FOV of the output lenslet array.  ... 
doi:10.1364/optica.3.000536 fatcat:teli7f4nfzallghqmk536qm6cu

Total Synthesis of Luminacin D

J. Brad Shotwell, Evan S. Krygowski, John Hines, Brian Koh, Elliott W. D. Huntsman, Hui Won Choi, John S. Schneekloth,, John L. Wood, Craig M. Crews
2002 Organic Letters  
See: (a) Sharma, S.; Oneyama, C.; Yamashita, Y.; Nakano, H.; Sugawara, K.; Hamada, M.; Kosaka, N.; Tamaoki, T. Oncogene 2001, 20, 2068-2079. (b) Oneyama, C.; Nakano, H.; Sharma, S.  ...  .; Nakano, S.; Narazaki, F.; Nakamura, Y. Tetrahedron Lett. 2001, 42, 7625-7628.  ... 
doi:10.1021/ol026382q pmid:12201723 pmcid:PMC2556570 fatcat:vqgxpsb6yndndkbjemf77bukoe

Primary Motor Cortex Encodes A Temporal Difference Reinforcement Learning Process [article]

Venkata S Aditya Tarigoppula, John S Choi, John H Hessburg, David B McNiel, Brandi T Marsh, Joseph Thachil Francis
2018 bioRxiv   pre-print
NHPs S and PG performed a cued GF task manually.  ...  Such a prediction matches the observed neural response in NHPs S and PG to this task.  ... 
doi:10.1101/257337 fatcat:6uzusgp4yja2pnmgk5gf5gvgcy

Perilymph Osmolality Modulates Cochlear Function

Chul-Hee Choi, John S. Oghalai
2008 The Laryngoscope  
Objectives/Hypothesis-The cochlear amplifier is required for the exquisite sensitivity of mammalian hearing. Outer hair cells underlie the cochlear amplifier and they are unique in that they maintain an intracellular turgor pressure. Changing the turgor pressure of an isolated outer hair cells through osmotic challenge modulates its ability to produce electromotile force. We sought to determine the effect of osmotic challenge on cochlear function. Study Design-In vivo animal study.
more » ... onic and hypertonic artificial perilymph was perfused through the scala tympani of anesthetized guinea pigs. Cochlear function was assessed by measuring the compound action potential, distortion product otoacoustic emissions, the cochlear microphonic, and the endocochlear potential. Results-Hypotonic perilymph decreased and hypertonic perilymph increased compound action potential and distortion product otoacoustic emission thresholds in a dose-dependent and reversible manner. The cochlear microphonic quadratic distortion product magnitude increased after hypotonic perfusion and decreased with hypertonic perfusion. There were no changes in the stimulus intensity growth curve of the low-frequency cochlear microphonic. The endocochlear potential was not affected by perilymph osmolality. Conclusions-These data demonstrate that perilymph osmolality can modulate cochlear function and are consistent with what would be expected if outer hair cells turgor pressure changes the gain of the cochlear amplifier in vivo.
doi:10.1097/mlg.0b013e3181788d72 pmid:18607303 pmcid:PMC3597111 fatcat:ntyomlellfcnxg6uj3fdgesdqa

Paraxial full-field cloaking

Joseph S. Choi, John C. Howell
2015 Optics Express  
We complete the 'paraxial' (small-angle) ray optics cloaking formalism presented previously [Choi and Howell, Opt. Express 22, 29465 (2014)], by extending it to the full-field of light.  ...  One method for broadband phase matching is to add a thin, flat plate to a ray optics cloak, anywhere between the background object(s) and the observer.  ...  Ultimately, the choice of which to use should depend on physically realizable n c 's. A few such solutions, that phase-corrects the four lens ray optics cloak in [19] , are shown in Fig. 2 .  ... 
doi:10.1364/oe.23.015857 pmid:26193564 fatcat:44m5i3tmszezpmjg3jf4lnylcm

Repurposing the yeast peroxisome to compartmentalize a toxic enzyme enables improved (S)-reticuline production [article]

Parbir S Grewal, Jennifer A Samson, Jordan J Baker, Brian Choi, John E Dueber
2020 bioRxiv   pre-print
enzyme which catalyzes the first committed reaction in benzylisoquinoline alkaloid (BIA) biosynthesis, is toxic when expressed cytosolically in Saccharomyces cerevisiae and, consequently, restricts (S)  ...  We identified that peroxisome protein capacity in S. cerevisiae becomes a limiting factor for further improvement of BIA production and demonstrate that expression of engineered transcription factors can  ...  converts (S)-norcoclaurine to (S)-reticuline in the cytosol ( Fig. 3) .  ... 
doi:10.1101/2020.03.23.000851 fatcat:qxz6jfd3vzg7jiwtrpkbghkzsi

Changes in Cellular Structures Revealed by Ultra-high Resolution Retinal Imaging in Optic Neuropathies

Stacey S. Choi, Robert J. Zawadzki, John L. Keltner, John S. Werner
2008 Investigative Ophthalmology and Visual Science  
T, temporal; N, nasal; S, superior; I, inferior; R, retina.  ...  Highly magnified and detailed volumetric cross-sectional images of the retina (0.5 ϫ 0.5 mm, 500 A lines; , 50 s; frame acquisition rate, 36 frames/s with 250 frames), subtending ϳ1.7°on the retina, were  ... 
doi:10.1167/iovs.07-0980 pmid:18436843 pmcid:PMC2707837 fatcat:4q6xayynp5elbbaxycfmkp5ajm

Microstructural Abnormalities Revealed by High Resolution Imaging Systems in Central Macular Arteriovenous Malformation

David G. Telander, Stacey S. Choi, Robert J. Zawadzki, Neal Berger, John L. Keltner, John S. Werner
2010 Ophthalmic surgery, lasers & imaging  
Using high-resolution spectral-domain optical coherence tomography (SD-OCT) and adaptive optics (AO) imaging, photoreceptor damage in a patient with a central macular arteriovenous malformation (AVM) and otherwise unexplained progressive vision loss was demonstrated. This patient presented with a central scotoma, a macular AVM, and no evidence of macular edema, retinal hemorrhage, or subretinal fluid. Fluorescein angiography (FA) did not reveal leakage. Over 28 years, her vision progressively
more » ... rsened from 20/25 to 20/400. Both time-domain OCT and FA did not reveal any significant retinal abnormality. However, high-resolution SD-OCT imaging revealed clear disorganization of the outer segments and focal photoreceptor disruption adjacent to the AVM. En face AO images further revealed loss of the photoreceptors in these regions. This case demonstrates the unique finding of progressive vision loss in a patient with a congenital retinal AVM, and how high-resolution imaging can detect structural changes of the retina in patients with otherwise unexplained vision loss.
doi:10.3928/15428877-20100215-99 pmid:20337274 pmcid:PMC3023842 fatcat:4tlqnnalz5ctrnc6oxqogh3iay

Mitochondrial DNA in Sepsis

John S. Harrington, Augustine M.K. Choi, Kiichi Nakahira
2017 Current Opinion in Critical Care  
Purpose of review Our understanding of critical illness is transforming as we develop a better understanding of the impact pathogen-associated molecular patterns and damage-associated molecular patterns (DAMPs) have on the pathogenesis of disease. Of the known DAMPs, there is a growing interest in mitochondrial DNA (mtDNA) as a DAMP capable of propagating the inflammatory response seen in sepsis and other conditions. In this review, we describe the varying mechanisms by which mtDNA is
more » ... ed from mitochondria into cytosol and the extracellular space where it can illicit an inflammatory response. In addition, we present some of the most recent clinical studies to examine mtDNA in critical illness. Recent findings Basic science research provides convincing data that mtDNA can influence the immune system through tolllike receptor 9 and inflammasomes. Clinical trials provide evidence that mtDNA is elevated in critically ill patients and is associated with mortality. Summary Although mtDNA is a DAMP shown to be elevated in numerous conditions, the clinical ramifications of this finding remain elusive. Further work is needed to determine if mtDNA can be utilized as a biomarker of disease severity or mortality.
doi:10.1097/mcc.0000000000000427 pmid:28562385 pmcid:PMC5675027 fatcat:cqjwlbnrqfg4joox2rcokm23wm

In Vivo Imaging of the Photoreceptor Mosaic in Retinal Dystrophies and Correlations with Visual Function

Stacey S. Choi, Nathan Doble, Joseph L. Hardy, Steven M. Jones, John L. Keltner, Scot S. Olivier, John S. Werner
2006 Investigative Ophthalmology and Visual Science  
N = nasal, S = Superior, I = Inferior. VF = visual field.  ...  Invest Ophthalmol Vis Sci. 1974;13:487-498. 31 Li Z, Jacobson S, Milam A. Autosomal dominant retinitis pigmentosa caused by the Table 2.  ... 
doi:10.1167/iovs.05-0997 pmid:16639019 pmcid:PMC2583223 fatcat:2tr7zc7pujhlris6cbq4mea53a

FINE RETINAL STRIAE ASSOCIATED WITH EPIRETINAL MEMBRANE VISUALIZED USING ADAPTIVE OPTICS

Susanna S. Park, Stacey S. Choi, Robert J. Zawadzki, John S. Werner
2009 Retinal cases & brief reports  
To describe a case of fine retinal striae visualized using an adaptive optics flood illuminated (AO-flood) fundus camera in a patient with vision loss from an idiopathic macular epiretinal membrane (ERM). A case report of a 48-year-old woman with recent vision loss from ERM imaged using an AO-flood fundus camera and high resolution Fourier-domain optical coherence tomography (Fd-OCT) before and 3 months after vitrectomy. Visual acuity improved from 20/70 to 20/20 after vitrectomy. Preoperative
more » ... d-OCT showed severe cystoid macular edema with irregularities in the outer nuclear layer which consists of cell bodies of photoreceptors. Preoperative AO-flood en face images showed dark linear striae of approximately 10 μm width overlying the cone mosaic that improved following surgery, concurrent with improvement in visual acuity and morphologic changes on Fd-OCT. Microstructural changes within the retinal layers resulting from macular traction from ERM can be visualized using an AO-flood fundus camera and Fd-OCT. They can appear as fine linear striae in AO-flood en face images. Further studies are needed to correlate these changes with vision loss associated with this condition.
doi:10.1097/icb.0b013e31816b31bb pmid:22880136 pmcid:PMC3413271 fatcat:56meodulhndtdmv4gwxzrf77ye

HIGH RESOLUTION FOURIER-DOMAIN OPTICAL COHERENCE TOMOGRAPHY OF RETINAL ANGIOMATOUS PROLIFERATION

STEVEN N. TRUONG, SUHAIL ALAM, ROBERT J. ZAWADZKI, STACEY S. CHOI, DAVID G. TELANDER, SUSANNA S. PARK, JOHN S. WERNER, LAWRENCE S. MORSE
2007 Retina  
A raster series of 100 B-scans (1000 A-scans/frame, 9 frames/s) imaged over a 6 mm ϫ 6 mm ϫ 2 mm volume of retina (lateral ϫ lateral ϫ depth) centered over the RAP lesion was obtained.  ... 
doi:10.1097/iae.0b013e31805468fd pmid:17891017 pmcid:PMC2583219 fatcat:nqt7ohsdwbfwfedmoobhnzwata

Does advertising promote smokeless tobacco use among adolescent boys? Evidence from California

Won S Choi, Arthur J Farkas, Bradley Rosbrook, John P Elder, John P Pierce
1995 Tobacco Control  
Objectives -To assess trends in smoke less tobacco use and to identify risk factors that distinguish youths who use or who are at risk of using smokeless tobacco. Design -Population based telephone
doi:10.1136/tc.4.suppl1.s57 fatcat:e5agnswbzvhetiat5xa2emuuqu

Paraxial ray optics cloaking

Joseph S. Choi, John C. Howell
2014 Optics Express  
For the following, we will use f 's to denote the focal lengths, and t's to denote the distances between the optical elements ( Fig. 2 (b)-(d)).  ...  (b)-(d) Diagrams for a two lens (b), three lens (c), or four lens (d) system. f 's are the focal lengths, t's are the distances between the elements.  ... 
doi:10.1364/oe.22.029465 pmid:25606881 fatcat:4uvwlthwbfci7nrkl5ks2dkxp4

Digital integral cloaking

Joseph S. Choi, John C. Howell, Arthur J. Davis, Cornelius F. Hahlweg, Joseph R. Mulley
2016 Novel Optical Systems Design and Optimization XIX  
For our setup (Fig. 2 ), the input scan required 29 s, and the computational processing required 22 s on the laptop that ran our code.  ...  For example, the horizontal scan distance required is (W s 2L tanFOV l ∕2). Here, W s is the active screen width of the output display, and FOV l is the FOV of the output lenslet array.  ... 
doi:10.1117/12.2242915 fatcat:w47442qnhvgdrm6rmhngtszkbi
« Previous Showing results 1 — 15 out of 42,337 results