Bryan Spann
A5085751625- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Mechanical and Optical Resonators
- Functional Brain Connectivity Studies
- Alzheimer's disease research and treatments
- Strong Light-Matter Interactions
- Advanced Neuroimaging Techniques and Applications
- Thermal Radiation and Cooling Technologies
- Dementia and Cognitive Impairment Research
- Perovskite Materials and Applications
- Spectroscopy and Quantum Chemical Studies
- Thermal properties of materials
- Brain Tumor Detection and Classification
- Advanced Thermoelectric Materials and Devices
- Photonic and Optical Devices
- Molecular Junctions and Nanostructures
- Plasmonic and Surface Plasmon Research
- Nanocluster Synthesis and Applications
- Obstructive Sleep Apnea Research
- S100 Proteins and Annexins
- Epigenetics and DNA Methylation
- Nanofluid Flow and Heat Transfer
- Neurobiology of Language and Bilingualism
- MRI in cancer diagnosis
- Quantum Electrodynamics and Casimir Effect
Cornell University
2017-2019
Houston Methodist
2013-2019
Weill Cornell Medicine
2019
Banner Sun Health Research Institute
2018-2019
National Institute of Standards and Technology
2016-2018
University of Southern California
2009-2018
Methodist Hospital
2017
National Academies of Sciences, Engineering, and Medicine
2016
Purdue University West Lafayette
2012-2015
United States Naval Research Laboratory
2015
Abstract Alzheimer’s Disease (AD) is a progressive neurodegenerative disease where biomarkers for based on pathophysiology may be able to provide objective measures diagnosis and staging. Neuroimaging scans acquired from MRI metabolism images obtained by FDG-PET in-vivo measurements of structure function (glucose metabolism) in living brain. It hypothesized that combining multiple different image modalities providing complementary information could help improve early AD. In this paper, we...
Abstract Coupling vibrational transitions to resonant optical modes creates polaritons shifted from the uncoupled molecular resonances and provides a convenient way modify energetics of vibrations. This approach is viable method explore controlling chemical reactivity. In this work, we report pump–probe infrared spectroscopy cavity-coupled C–O stretching band W(CO) 6 direct measurement lifetime vibration-cavity polariton. The upper polariton relaxes 10 times more quickly than mode. Tuning...
A recently identified variant within the fat mass and obesity-associated (FTO) gene is carried by 46% of Western Europeans associated with an approximately 1.2 kg higher weight, on average, in adults 1 cm greater waist circumference. With >1 billion overweight 300 million obese persons worldwide, it crucial to understand implications carrying this very common allele for health our aging population. FTO highly expressed brain elevated body index (BMI) atrophy, but unknown how risk affects...
Regions of the temporal and parietal lobes are particularly damaged in Alzheimer's disease (AD), this leads to a predictable pattern brain atrophy. In vivo quantification subregional atrophy, such as changes cortical thickness or structure volume, could lead improved diagnosis better assessment neuroprotective effects therapy. Toward end, we have developed fast robust method for accurately quantifying cerebral structural several subcortical regions using serial MRI scans. 169 healthy...
Designing coupled vibrational-cavity polariton systems to modify chemical reaction rates and paths requires an understanding of how this coupling depends on system parameters (i.e., absorber strength, modal distribution, vibrational cavity line widths). Here, we evaluate the impact absorption coefficient design normal mode between a Fabry–Pérot molecular vibration. For band urethane in polymer matrix, strength increases with its concentration so that spans weak strong regimes. The...
Accurate diagnosis of mild cognitive impairment (MCI) before conversion to Alzheimer's disease (AD) is invaluable for patient treatment. Many works showed that MCI and AD affect functional structural connections between brain regions as well the shape cortical regions. However, 'shape connections' are rarely investigated -e.g., how morphological attributes such thickness sulcal depth a specific region change in relation other To fill this gap, we unprecedentedly design multiplexes late...
In Alzheimer's disease (AD), early deficits in learning and memory are a consequence of synaptic modification induced by toxic beta-amyloid oligomers (oAβ). To identify immediate molecular targets downstream oAβ binding, we prepared synaptoneurosomes from prefrontal cortex control incipient AD (IAD) patients, isolated mRNAs for comparison gene expression. This novel approach concentrates mRNA, thereby increasing the ratio to somal mRNA allowing discrimination expression changes synaptically...
Loss-of-function mutations in the genes associated with primary microcephaly (MCPH) reduce human brain size by about two-thirds, without producing gross abnormalities organization or physiology and leaving other organs largely unaffected [Woods CG, et al. (2005) Am J Hum Genet 76:717-728]. There is also evidence suggesting that MCPH have evolved rapidly primates humans been subjected to selection recent evolution [Vallender EJ, (2008) Trends Neurosci 31:637-644]. Here, we show common...
We report a micro-Raman-based optical method to measure in-plane thermal conductivity of ultrathin films. With the use 20-nm-thick SiO2 substrates that assure heat transfer, sub-100-nm Bi films and Al2O3 as thin 5 nm were successfully measured. The results reveal phonon boundary scattering, both at surface/interface grain boundaries, reduces lattice conductivity. measurements amorphous accomplished using film Raman temperature sensor, agree with minimum models for dielectrics. Our work...
Abstract The introduction of mild cognitive impairment (MCI) as a diagnostic category adds to the challenges diagnosing Alzheimer’s Disease (AD). No single marker has been proven accurately categorize patients into their respective groups. Thus, previous studies have attempted develop fused predictors AD and MCI. These two main limitations. Most do not simultaneously consider all categories provide suboptimal representations using same set modalities for prediction classes. In this work, we...
The central as well peripheral corneal epithelium of normal young adult mice consisted light (young), medium (mature) and dark (hypermature) cells based upon their brightness under the scanning beam. Multiple holes either partial or full thickness were observed in these more common cells. Small large mounds devoid microvilli also found TEM revealed presence small cytoplasmic vesicles. Rupture vesicles cell plasma membrane appeared to contribute formation epithelial holes. Full within...
We employ ultrafast transient absorption spectroscopy with temporal pulse shaping to manipulate coherent phonon excitation and quantify the strength of electron-phonon coupling in CdTe1−xSex nanocrystals (NCs). Raman active CdSe CdTe longitudinal optical (LO) modes are excited probed time domain. By temporally controlling pump pairs coherently excite cancel phonons NCs, we estimate relative amount energy that is coupled LO mode.
Ultrafast time-resolved absorption spectroscopy is used to investigate exciton dynamics in CdSe nanocrystal films. The effects of morphology, quantum-dot versus quantum-rod, and preparation nanocrystals a thin film form are investigated. measurements revealed longer intraband relaxation quantum-rods than quantum-dots. slowed due mitigation the Auger-relaxation mechanism from elongating nanocrystal. In addition, showed long-lived confined acoustic phonons corresponding ellipsoidal breathing...
We show a means of increasing charge transfer in CdS–TiO<sub>2</sub> heterojunctions by laser sintering TiO<sub>2</sub> nanocrystals.
Ultrafast transient absorption spectroscopy was employed to investigate intraband relaxation and coherent acoustic phonons in quantum dots (QDs) rods (QRs) of various sizes. We found that the hot electrons holes relaxed through a nonradiative Auger thermalization mechanism circumvents phonon bottleneck effect, resulting sub-2.5 ps times. The QRs showed an increased time when compared with QDs as result formation 1D exciton along axial dimension, which partially mitigates mechanism. longer...
Although abnormally folded tau protein has been found to selfpropagate from neuron connected neuron, similar propagation through human brain networks not fully documented.We studied in the left hemispheric syntactic network, which comprises an anterior frontal node and a posterior temporal by white matter of arcuate fasciculus.This network is affected nonfluent variant primary progressive aphasia, neurodegenerative disorder with accumulation.Methods: Eight patients aphasia (age, 67.0 ± 7.4...
The recent development of quasi-two-dimensional (2D) semiconducting nanomaterials [nanoplatelets (NPLs)] prepared through solution-based chemistry has attracted significant attention in the field color conversion materials. Herein, we demonstrate efficient high-temperature photoluminescence as-prepared cadmium telluride NPLs from 300 to 500 K with visually observable emission at temperatures as high K. Indeed, thermal-emission quenching solution was found be not only reversible following...
Developments in manufacturing have led to progressively smaller and more complex micro-elctro-mechanical systems (MEMS), many of which employ heat exchangers enhance performance. Due the size constraints on these devices, adiabatic surfaces are difficult create, thus, ambient thermal interaction becomes an import factor exchanger Similarly, end-wall boundary conditions also become a concern at this scale. A closed form mathematical solution is presented for single-pass, two-fluid, parallel...
To compare regional and cortical cerebral blood flow (CBF) from ASL-MRI with18FDG-PET in neurodegenerative disease.
Sub-diffractional confinement of light has led to advancements in imaging, metamaterials, nano-manufacturing, plasmonics, and other fields. One potential route sub-diffractional is via stimulated surface phonon polaritons (SPhPs). SPhPs couple infrared photons with optical phonons consequently their lifetimes can be longer than plasmon (SPPs), whose are dominated by electron scattering events. Thus, materials capable generating general interest study. activated energies near the Reststrahlen...
Coherent coupling between an optical-transition and confined optical mode, when sufficiently strong, gives rise to new modes separated by the vacuum Rabi splitting. Such systems have been investigated for electronic-state transitions, however, only very recently vibrational transitions considered. Here, we bring strong polaritonic-coupling in cavities from visible into infrared where a range of static dynamic processes await investigation. First, experimentally numerically describe...
One potential way to increase photovoltaic efficiency is take advantage of hot-carriers. Nanocrystal based solar cells aim hot-carrier capture boost device performance. The crucial parameter for gauging a given nanocrystal material this application the electron-phonon coupling. coupling will dictate thermalization time In study we demonstrate method quantifying in semiconductor nanocrystals. By employing ultrafast transient absorption spectroscopy with temporal pulse shaping, manipulate...