A5001277224- Force Microscopy Techniques and Applications
- Carbon Nanotubes in Composites
- Cellular Mechanics and Interactions
- Blood properties and coagulation
- Mechanical and Optical Resonators
- Microfluidic and Bio-sensing Technologies
- Micro and Nano Robotics
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy and Quantum Chemical Studies
- Nanotechnology research and applications
- Elasticity and Material Modeling
- Cancer and biochemical research
- Advanced Materials and Mechanics
- Characterization and Applications of Magnetic Nanoparticles
- Tracheal and airway disorders
- Cell Adhesion Molecules Research
- Adhesion, Friction, and Surface Interactions
- Graphene research and applications
- Modular Robots and Swarm Intelligence
- Microtubule and mitosis dynamics
- Advanced MEMS and NEMS Technologies
- Erythrocyte Function and Pathophysiology
- Molecular Junctions and Nanostructures
- Airway Management and Intubation Techniques
- Spectroscopy and Laser Applications
University of North Carolina at Chapel Hill
2012-2021
Applied Physical Sciences (United States)
2018-2021
Physical Sciences (United States)
2018
University of North Carolina Health Care
2009-2017
Rheomics (United States)
2015
Communities In Schools of Orange County
2014
Duke University Hospital
2011
Duke University
2011
Duke Medical Center
2011
Astronomy and Space
1997-2009
Using infrared-visible sum-frequency generation we have obtained the OH stretch vibrational spectra of water at vapor/water interface. From spectra, deduce that more than 20% surface molecules one free projecting into vapor. The spectrum is weakly temperature dependent from 10 to 80 \ifmmode^\circ\else\textdegree\fi{}C. A monolayer fatty alcohol on terminates groups and induces an icelike structure in spectrum.
Cancer cells are defined by their ability to invade through the basement membrane, a critical step during metastasis. While increased secretion of proteases, which facilitates degradation and alterations in cytoskeletal architecture cancer have been previously studied, contribution mechanical properties invasion is unclear. Here, we applied magnetic tweezer system establish that stiffness patient tumor cell lines inversely correlates with migration three-dimensional membranes, correlation...
We present a procedure for producing high-aspect-ratio cantilevered micro- and nanorod arrays of PDMS−ferrofluid composite material. The rods have been produced with diameters ranging from 200 nm to 1 μm aspect ratios as high 125. demonstrate actuation these superparamagnetic rod an externally applied magnetic field permanent magnet compare this theoretical energy-minimization model. structures by methods may be useful in microfluidics, photonic, sensing applications.
Blood clots perform an essential mechanical task, yet the behavior of fibrin fibers, which form structural framework a clot, is largely unknown. By using combined atomic force-fluorescence microscopy, we determined elastic limit and extensibility individual fibers. Fibrin fibers can be strained 180% (2.8-fold extension) without sustaining permanent lengthening, they up to 525% (average 330%) before rupturing. This largest observed for protein The data imply that monomers must able undergo...
We present here the use of amino-terminated DNA strands in functionalizing open ends and defect sites oxidatively prepared single-walled carbon nanotubes, an important first step realizing a DNA-guided self-assembly process for nanotubes.
Living systems employ cilia to control and sense the flow of fluids for many purposes, such as pumping, locomotion, feeding, tissue morphogenesis. Beyond their use in biology, functional arrays artificial have been envisaged a potential biomimetic strategy inducing fluid mixing lab-on-a-chip devices. Here we report on transport produced by magnetically actuated whose size approaches that biological counterparts, scale at which advection diffusion compete determine mass transport. Our...
A vexing problem in cystic fibrosis (CF) pathogenesis has been to explain the high prevalence of Pseudomonas aeruginosa biofilms CF airways. We speculated that airway surface liquid (ASL) hyperabsorption generates a concentrated mucus interacts with P. promote biofilms. To model vs. normal infections, (2.5% solids) and CF-like (8% were prepared, placed flat chambers, infected an ≈5 × 10 3 strain PAO1 . Although bacteria grew cfu/ml both concentrations, macrocolony formation was detected only...
The nanoManipulator system adds a virtual-reality interface to an atomic-force microscope (AFM), thus providing tool that can be used by scientists image and manipulate nanometer-sized molecular structures in controlled manner. As the AFM tip scans sample, tip-sample interaction forces are monitored, which, turn, yield information about frictional, mechanical, material, topological properties of sample. Computer graphics reconstruct surface for user, with color or contours overlaid indicate...
Using infrared-visible sum-frequency generation we have obtained the vibrational spectra of CH stretches methanol molecules at interface between vapor and liquid. This is first spectrum ever observed from a neat liquid surface. The measured polarization dependence phase nonlinear susceptibility allow us to conclude that surface are polar oriented with ${\mathrm{CH}}_{3}$ group pointing away very broad orientational distribution.
Cells experience mechanical forces throughout their lifetimes. Vinculin is critical for transmitting these forces, yet how it achieves its distinct functions at cell–cell and cell–matrix adhesions remains unanswered. Here, we show vinculin phosphorylated Y822 in cell–cell, but not cell–matrix, adhesions. Phosphorylation was elevated when were applied to E-cadherin required integrate into the cadherin complex. The mutation Y822F ablated activities prevented cells from stiffening response on...
Malignant melanoma is characterized by a propensity for early lymphatic and hematogenous spread. The hypoxia-inducible factor (HIF) family of transcription factors upregulated in key oncogenic drivers. HIFs promote the activation genes involved cancer initiation, progression, metastases. Hypoxia has been shown to enhance invasiveness metastatic potential tumor cells regulating breakdown ECM as well that control motility adhesion cells. Using Pten-deficient, Braf-mutant genetically engineered...
Chromatin and lamin A/C separately resist strain in nuclear volume surface area, respectively, during compression as studied with combined atomic force microscopy light sheet imaging. decompaction further alters curvature dynamics indentation.
We report on the characterization of nanometer-scale resonators. Each device incorporates one multiwalled carbon nanotube (MWNT) as a torsional spring. The devices are actuated electrostatically, and their deflections, both low frequency resonance, detected optically. These some smallest electromechanical ever created demonstration practical integrated MWNT-based oscillators. results also show surprising intershell mechanical coupling behavior in MWNTs.
We present local conductance measurements of carbon nanotube networks with nanometer scale resolution and show that there are discrete drops in correspond to junctions metallic nanotubes semiconducting nanotubes. The anomalies these compared thin films shown, a new method discerning between single-wall is demonstrated.
We present what are to our knowledge the first measurements of phase infrared-visible sum-frequency generation signal. introduce two techniques and apply determination polar orientation a selected group atoms within an adsorbed molecule.
By studying a single crystal of polydiacetylene-toluene-sulfonate, we have made the first identification triplet excited state conjugated polymer. The basis for this is magnetic field dependence excited-state lifetime, which measured by time-resolved optical absorption. Additionally, detected $\ensuremath{\Delta}m=\ifmmode\pm\else\textpm\fi{}1$ transitions between sublevels measuring microwave-induced changes in triplet-state lifetime.