A5022917114- Spectroscopy and Quantum Chemical Studies
- Phytochemicals and Antioxidant Activities
- High voltage insulation and dielectric phenomena
- Dielectric materials and actuators
- Electrochemical Analysis and Applications
- Molecular spectroscopy and chirality
- Synthesis and properties of polymers
- Thermodynamic properties of mixtures
- Spectroscopy and Laser Applications
- Advancements in Battery Materials
- Muon and positron interactions and applications
- Postharvest Quality and Shelf Life Management
- Ionic liquids properties and applications
- Lipid Membrane Structure and Behavior
- Advanced Battery Materials and Technologies
- Energetic Materials and Combustion
- Ion channel regulation and function
- Nanocomposite Films for Food Packaging
- Silicone and Siloxane Chemistry
- Pomegranate: compositions and health benefits
- Lignin and Wood Chemistry
- Ferroelectric and Piezoelectric Materials
- Diabetes Treatment and Management
- Electrohydrodynamics and Fluid Dynamics
- Molecular Spectroscopy and Structure
Stanford University
2020-2025
Zhengzhou Fruit Research Institute
2022-2025
Chinese Academy of Agricultural Sciences
2022-2025
University of Wisconsin–Madison
2018-2019
Abstract High‐temperature flexible polymer dielectrics are critical for high density energy storage and conversion. The need to simultaneously possess a bandgap, dielectric constant glass transition temperature forms substantial design challenge novel polymers. Here, by varying halogen substituents of an aromatic pendant hanging off bicyclic mainchain polymer, class high‐temperature olefins with adjustable thermal stability obtained, all uncompromised large bandgaps. Halogens substitution...
With the aim to establish a structure-inhibitory activity relationship of flavonoids against dipeptidyl peptidase-4 (DPP-4) and elucidate interaction mechanisms between them, pannel 70 structurally diverse was used evaluate their inhibitory activities DPP-4, among which myricetin, hyperoside, narcissoside, cyanidin 3-O-glucoside, isoliquiritigenin showed higher in concentration-dependent manner. Structure-activity analysis revealed that introducing hydroxyl groups C3', C4', C6 flavonoid...
The size, size distribution, dynamics, and electrostatic properties of free volume elements (FVEs) in polystyrene (PS) poly(methyl methacrylate) (PMMA) were investigated using the Restricted Orientation Anisotropy Method (ROAM), an ultrafast infrared spectroscopic technique. restricted orientational dynamics a vibrational probe embedded polymer matrix provides detailed information on FVE sizes their probability distribution. probe's vary as function its frequency within inhomogeneously...
Epigallocatechin gallate (EGCG) and kaempferol exhibit cellular antioxidant activity; however, their interactive effects in terms of actions underlying mechanisms remain unclear. In this study, cytoprotective were examined against 2,2-azobis (2-amidinopropane) dihydrochloride solution (ABAP)-induced oxidative stress HepG2 cells. The results showed that the median effective dose (EC50) EGCG (6:1.5, c/c) combination was 3.4 ± 0.1 μg/mL, with a index (CIavg) value 0.54, which represented...
Health and environmental risks posed by volatile organic solvents create an incentive to develop safer, less with the appropriate functionality. Deep eutectic other low-volatility mixtures offer a highly tunable alternative through mixture composition selection. However, significant gap exists in understanding relationship between molecular-level properties resulting solvation transport properties. Using ultrafast infrared (IR) polarization-selective pump–probe (lifetimes orientational...
Abstract The search for safe, natural antimicrobial agents has received significant attention controlling postharvest diseases in fruits. This study evaluated the antifungal activity of pomegranate peel extracts (PPE) against 9 pathogenic fungi by different methods. Additionally, key polyphenol compounds were identified. Results revealed that n-hexane partitioned fraction ethanolic extract exhibited highest inhibition efficacy. A total 36 polyphenols, including 10 newly discovered...
The Restricted Orientation Anisotropy Method (ROAM) is a new technique for determining polymer free volume element (FVE) radii using ultrafast infrared (IR) polarization-selective pump–probe (PSPP) spectroscopy. ROAM utilizes small IR vibrational probe molecules as molecular rulers to measure the FVE and radius probability distribution (RPD). Here, we present rigorous test of method by performing experiments on polystyrene six different that have lengths shapes. In addition, enhance length...
Optimizing lithium-ion battery (LIB) electrolytes is essential for high-current applications such as electric vehicles, yet experimental techniques to characterize the complex structural dynamics responsible lithium transport within these are limited. In this study, we used ultrafast infrared spectroscopy measure chemical exchange, spectral diffusion, and solvation structures across a wide range of concentrations in propylene carbonate-based LiTFSI (lithium bis(trifluoromethanesulfonimide)...
A vibration's transition frequency is partly determined by the first-order Stark effect, which accounts for electric field experienced mode. Using ultrafast infrared pump-probe and FT-IR spectroscopies, we characterized both 0 → 1 2 vibrational transitions' field-dependent peak positions line widths of CN stretching mode benzonitrile (BZN) phenyl selenocyanate (PhSeCN) in ten solvents. We present a theoretical model that decomposes observed width into contribution field-independent non-Stark...
Significance Several experimental platforms and computational methods have been developed to identify DNA binding sites of over 1,000 transcription factors. Often, high-affinity (maximal) are reported as consensus motifs. Differences between contribute uncertainty in ascribing submaximal sites. However, biological studies emphasize the importance shaping regulatory functions To bridge this gap, we Differential Specificity Energy Landscapes unmask differences well capture distinct site...
Ultrafast infrared vibrational spectroscopy is widely used for the investigation of dynamics in systems from water to model membranes. Because experimental observation window limited a few times probe's lifetime, frequent obstacle measurement broad time range short molecular lifetimes (typically tens picoseconds). Five new long-lifetime aromatic selenocyanate probes have been synthesized and their properties characterized. These are compared commercial phenyl selenocyanate. The between ∼400...
The infrared pulses used to generate nonlinear signals from a vibrational probe can cause heating via solvent absorption. Solvent absorption followed by rapid relaxation produces unwanted heat creating spectral shifts of the and absorptions. are often isolated "chopping," i.e., alternately blocking one incident pulses. This method is standard in pump-probe transient experiments. As less deposited into sample when an pulse blocked, heat-induced give rise artificial signals. Here, we...
Measurement of molecular orientation relaxation using ultrafast infrared (IR) pump-probe experiments is widely used to understand the properties liquids and other systems. In simplest situation, anisotropy decay a single exponential reflecting diffusive orientational relaxation. However, frequently biexponential. The faster component caused by solvent caging restricting angular sampling until constraint release permits all angles be sampled. Here, we describe another mechanism that limits...
Ultrafast infrared (IR) spectroscopy was used to characterize the free volume element (FVE) radius probability distributions (RPDs) of poly(ether imide) (PEI) alumina nanocomposites. The nanocomposites (0–2 wt %) were prepared with 20 nm diameter spherical Al2O3 nanofillers and a small amount phenyl selenocyanate (PhSeCN) as IR vibrational probes. Restricted orientation anisotropy method (ROAM), an ultrafast technique, measure FVE radii. results yield RPDs function nanoparticle...
The theoretical framework for reorientation-induced spectral diffusion (RISD) describes the polarization dependence of dynamics as measured with two-dimensional (2D) correlation spectroscopy and related techniques. Generally, RISD relates to orientational molecular chromophore relative local electric fields medium. predictions have been shown be very sensitive both restricted (generally arising from steric hindrance) distribution probe (electrostatic ordering). Here, a theory that combines...