Physics:
The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
JoVE General
Optimization of the Ugi Reaction Using Parallel Synthesis and Automated Liquid Handling
1Department of Chemistry, Drexel University, 2Mettler-Toledo, 3Chemspider
The Ugi reaction has proved to be a convenient way to quickly create diverse libraries of compounds. It involves the reaction of an amine, an aldehyde, a carboxylic acid and an isonitrile typically in methanol at room temperature. In this video, we utilize a 48-slot Mettler-Toledo MiniBlock equipped with filtration tubes and a Mettler-Toledo MiniMapper automated liquid handler was used to deliver the reagents and solvent. The parameters of interest were the concentration, the solvent composition and the excess of some of the reagents.
JoVE Applied Physics
Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet (VUV) Synchrotron Radiation
Chemical Sciences Division, Lawrence Berkeley National Laboratory
A molecular beam coupled to tunable vacuum ultraviolet photoionization mass spectrometer at a synchrotron provides a convenient tool to explore the electronic structure of isolated gas phase molecules and clusters. Proton transfer mechanisms in DNA base dimers were elucidated with this technique.
JoVE Editorial
October 2011: This Month in JoVE
Here are some highlights from the October 2011 Issue of Journal of Visualized Experiments (JoVE).
JoVE Bioengineering
A Microfluidic-based Hydrodynamic Trap for Single Particles
1Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 2Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign
In this article, we present a microfluidic-based method for particle confinement based on hydrodynamic flow. We demonstrate stable particle trapping at a fluid stagnation point using a feedback control mechanism, thereby enabling confinement and micromanipulation of arbitrary particles in an integrated microdevice.
JoVE Bioengineering
Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma
Department of Mechanical and Aerospace Engineering, The George Washington University
Anodic arc discharge is one of the most practical and efficient methods to synthesize various carbon nanostructures. To increase the arc controllability and flexibility, a non-uniform magnetic field was introduced to process the one-step synthesis of large-scale graphene flakes and high-purity single-walled carbon nanotubes.
JoVE Editorial
October 2012: This Month in JoVE
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Here are some highlights from the October 2012 Issue of Journal of Visualized Experiments (JoVE).
JoVE Editorial
2012: A Year In Review
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Here's a look at some of the milestones and highlights of the year 2012 in Journal of Visualized Experiments (JoVE).
JoVE Applied Physics
Fabrication of Silica Ultra High Quality Factor Microresonators
1Department of Chemical Engineering and Materials Science, University of Southern California, 2Department of Electrical Engineering-Electrophysics, University of Southern California
We describe the use of a carbon dioxide laser reflow technique to fabricate silica resonant cavities, including free-standing microspheres and on-chip microtoroids. The reflow method removes surface imperfections, allowing long photon lifetimes within both devices. The resulting devices have ultra high quality factors, enabling applications ranging from telecommunications to biodetection.
JoVE Applied Physics
Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors
Mechanical Engineering Department, Southern Methodist University
A high-sensitivity photonic micro sensor was developed for electric field detection. The sensor exploits the optical modes of a dielectric sphere. Changes in the external electric field perturb the sphere morphology leading to shifts in its optical modes. The electric field strength is measured by monitoring these optical shifts.
JoVE Bioengineering
Studying Cell Rolling Trajectories on Asymmetric Receptor Patterns
1Department of Materials Science and Engineering, MIT - Massachusetts Institute of Technology, 2Department of Mechanical Engineering, MIT - Massachusetts Institute of Technology, 3HST Center for Biomedical Engineering and Harvard Stem Cell Institute, Brigham and Women's Hospital and Harvard Medical School
We describe a protocol to observe and analyze cell rolling trajectories on asymmetric receptor-patterned substrates. The resulting data are useful for engineering of receptor-patterned substrates for label-free cell separation and analysis.
JoVE General
Procedure for Fabricating Biofunctional Nanofibers
1Department of Chemistry, Clark Atlanta University, 2Department of Physics, Clark Atlanta University, 3Department of Chemistry and Chemical Biology, Cornell University
An efficient approach for preparing nanofibers decorated with functional groups capable of specifically interacting with proteins is described. The approach first requires the preparation of a polymer functionalized with the appropriate functional group. The functional polymer is fabricated into nanofibers by electrospinning. The effectiveness of the binding of the nanofibers with a protein is studied by confocal microscopy.
JoVE Applied Physics
Synthesis and Operation of Fluorescent-core Microcavities for Refractometric Sensing
Department of Physics, University of Alberta
Fluorescent-core microcavity sensors employ a high-index quantum-dot coating in the channel of silica microcapillaries. Changes in the refractive index of fluids pumped into the capillary channel cause shifts in the microcavity fluorescence spectrum that can be used to analyze the channel medium.
JoVE General
In situ Imaging of the Mouse Thymus Using 2-Photon Microscopy
Department of Molecular and Cell Biology, University of California, Berkeley
We present step-by-step instructions for the generation of neonatal chimeras as well as the dissection and preparation of the thymus for ex vivo imaging by 2-Photon Microscopy.
JoVE Bioengineering
Measurement of Tension Release During Laser Induced Axon Lesion to Evaluate Axonal Adhesion to the Substrate at Piconewton and Millisecond Resolution
1Institute of Biophysics, National Research Council of Italy, 2Dipartimento di Sistemi e Informatica, Università di Firenze, 3Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia
We measured the tension release in an axon that was partially lesioned with a laser dissector by simultaneous force spectroscopy measurement performed on an optically-trapped probe adhered to the membrane of the axon. The developed experimental protocol evaluates the axon adhesion to the culture substrate.
JoVE Neuroscience
Functional Mapping with Simultaneous MEG and EEG
Athinoula A. Martinos Center for Biomedical Imaging, MGH - Massachusetts General Hospital
We use magnetoencephalography (MEG) and electroencephalography (EEG) to map brain areas involved in the processing of simple sensory stimuli.
JoVE General
Measurement Of Neuromagnetic Brain Function In Pre-school Children With Custom Sized MEG
Macquarie Centre for Cognitive Science, Macquarie University
The advent of MEG systems sized for young children opens important new opportunities to study brain development. The new system, together with a protocol that aligns experimental requirements with the capacities of children, can be used to study cognitive and language processes in healthy, awake children aged three to six.
JoVE Neuroscience
Low-stress Route Learning Using the Lashley III Maze in Mice
1Department of Chemistry, Pennsylvania State University, 2Center for Developmental and Health Genetics, Pennsylvania State University, 3Department of Veterinary and Biomedical Sciences, Pennsylvania State University, 4Huck Institute of the Life Sciences, Pennsylvania State University, 5California NanoSystems Institute, University of California, Los Angeles, 6Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles
The Lashley III maze is a route-learning task that does not rely on aversive stimuli or visual cues. It is thus a highly attractive option for evaluating learning and memory, especially in aging mice or otherwise where stress is a consideration.
JoVE Applied Physics
Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses
Mechanical Engineering, Purdue University
An experimental method to examine the early plasma evolution induced by ultrashort laser pulses is described. Using this method, high quality images of early plasma are obtained with high temporal and spatial resolutions. A novel integrated atomistic model is used to simulate and explain the mechanisms of early plasma.
JoVE General
Visualizing Single Molecular Complexes In Vivo Using Advanced Fluorescence Microscopy
1Biochemistry, University of Oxford, 2Physics, University of Oxford
Here we demonstrate the protocols for performing single-molecule fluorescence microscopy on living bacterial cells to enable functional molecular complexes to be detected, tracked and quantified.
JoVE Applied Physics
Measuring Spatially- and Directionally-varying Light Scattering from Biological Material
1Department of Biomedical Science, Cornell University, 2Department of Ecology and Evolutionary Biology, Cornell University, 3Cornell University Museum of Vertebrates, 4Department of Computer Science, Cornell University
We present a non-destructive method for sampling spatial variation in the direction of light scattered from structurally complex materials. By keeping the material intact, we preserve gross-scale scattering behavior, while concurrently capturing fine-scale directional contributions with high-resolution imaging. Results are visualized in software at biologically-relevant positions and scales.
JoVE Chemistry
Origami Inspired Self-assembly of Patterned and Reconfigurable Particles
1Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, 2Department of Chemistry, The Johns Hopkins University
We describe experimental details of the synthesis of patterned and reconfigurable particles from two dimensional (2D) precursors. This methodology can be used to create particles in a variety of shapes including polyhedra and grasping devices at length scales ranging from the micro to centimeter scale.
JoVE Editorial
November 2012: This Month in JoVE
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
In this issue, Oestreicher et al. show us how to isolate magnetotactic bacteria from freshwater samples, and concentrate the bacteria at one end of a glass capillary. The magnetotactic bacteria can then be visualized by light and transmission electron microscopy, and used for various other assays.
JoVE Editorial
February 2013: This Month in JoVE
1Department of Ophthalmology, Massachusetts Eye and Ear, 2JoVE Content Production
Here's a look at what's coming up in the February 2013 Issue of Journal of Visualized Experiments (JoVE).
JoVE Editorial
July 2012: This Month in JoVE
1JoVE Content Production, 2Department of Ophthalmology, Massachusetts Eye and Ear
Historically, JoVE, The Journal of Visualized Experiments, has focused primarily on biomedical research and has developed subsections for Bioengineering, Clinical and Translational Medicine, Immunology and Infection, and Neuroscience. This July, JoVE launches its Applied Physics section, which includes a range of content from Plasma Physics to Materials Science. We begin the new section with a notable article from Purdue University, where researchers in the Center for Laser-Based Manufacturing are studying.
JoVE Neuroscience
Automated Quantification of Synaptic Fluorescence in C. elegans
Department of Biological Sciences, University of Toledo
The abundance of neurotransmitter receptors clustered at synapses strongly influences synaptic strength. This method quantifies fluorescently-labeled neurotransmitter receptors in three dimensions with single-synapse resolution in C. elegans, allowing hundreds of synapses to be rapidly characterized within a single sample without distortions introduced by z-plane projection.
JoVE Neuroscience
Culturing and Electrophysiology of Cells on NRCC Patch-clamp Chips
1Institute for Microstructural Sciences, National Research Council of Canada, 2Institute for Biological Sciences, National Research Council of Canada, 3Hotchkiss Brain Institute, University of Calgary
We show how planar patch-clamp chips fabricated at the National Research Council of Canada are sterilized, primed, loaded with medium, plated with cells, and used for electrophysiological recordings.
JoVE General
AC Electrokinetic Phenomena Generated by Microelectrode Structures
1Biomedical Engineering, Science and Health Systems, Drexel University, 2Mechanical Engineering and Mechanics, Drexel University
Manipulating fluids and suspended particles in the micro- and nano-scale is becoming more of a reality as enabling technologies, like AC electrokinetics, continue to develop. Here, we discuss the physics behind AC electrokinetics, how to fabricate these devices and how to interpret the experimental observations.
JoVE Clinical and Translational Medicine
MRI-guided Disruption of the Blood-brain Barrier using Transcranial Focused Ultrasound in a Rat Model
1Imaging Research, Sunnybrook Research Institute, 2Department of Medical Biophysics, University of Toronto, 3Department of Medical Biophysics, and Institute of Biomaterials & Biomedical Engineering (IBBME), University of Toronto
Microbubble-mediated focused ultrasound disruption of the blood-brain barrier (BBB) is a promising technique for non-invasive targeted drug delivery in the brain1-3. This protocol outlines the experimental procedure for MRI-guided transcranial BBB disruption in a rat model.
JoVE Editorial
An Interview with Nobel Laureate Theodor Hansch, Physics 2005
Theodor Hänsch was a co-recipient of the 2005 Nobel Prize in Physics for "contributions to the development of laser-based precision spectroscopy, including the optical frequency comb." In this video, Hänsch explains "in a nutshell" the frequency comb, its theories, its many applications, and the breakneck pace of the research leading up to the Nobel Prize.
JoVE Neuroscience
A Polished and Reinforced Thinned-skull Window for Long-term Imaging of the Mouse Brain
1Department of Physics, University of California, San Diego, 2Department of Engineering Science and Mechanics, Pennsylvania State University, 3Department of Neurosurgery, Pennsylvania State University, 4Section of Neurobiology, University of California, San Diego
We present a method to form an imaging window in the mouse skull that spans millimeters and is stable for months without inflammation of the brain. This method is well suited for longitudinal studies of blood flow, cellular dynamics, and cell/vascular structure using two-photon microscopy.
JoVE Neuroscience
C. elegans Tracking and Behavioral Measurement
1Donnelly Centre, University of Toronto, 2Department of Physics and Astronomy, Vrije Universiteit, 3Okinawa Institute of Science and Technology, 4Department of Physics, University of Toronto
We have developed a video-rate tracking microscope system that can record and quantify C. elegans behavior at high resolution and high speeds. We have also developed computational methods to reduce the dimensionality of the worm images to a fundamental set of measurements that completely describe the shape of the worm.
JoVE General
Automated System for Single Molecule Fluorescence Measurements of Surface-immobilized Biomolecules
1Physics Department, Boston University, 2Department of Biomedical Engineering, Boston University
In this article we describe how we obtain FRET traces from individual DNA molecules immobilized to a surface using an automated scanning confocal microscope.
JoVE General
PuraMatrix Encapsulation of Cancer Cells
1Wellman Center for Photomedicine Massachusetts General Hospital, Harvard Medical School, 2Thayer School of Engineering, Dartmouth College, 3Department of Dermatology, Harvard Medical School
This video demonstrates how to encapsulate and culture cancer cells in PuraMatrix, a commercially available self assembling peptide gel.
JoVE General
Live Cell Response to Mechanical Stimulation Studied by Integrated Optical and Atomic Force Microscopy
1Department of Systems Biology and Translational Medicine, College of Medicine, Cardiovascular Research Institute, Texas A&M Health Science Center, 2Department of Biomedical Engineering, Texas A&M University
This paper aims to instruct the reader in the operation of an integrated atomic force-optical imaging microscope for mechanical stimulation of live cells in culture. A step-by-step protocol is presented. A representative data set that shows live cell response to mechanical stimulation is presented.
JoVE Applied Physics
Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM
1Center for Nanoscale Materials, Argonne National Laboratory, 2Institute for Molecular Engineering, University of Chicago
Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.
JoVE Bioengineering
Increasing cDNA Yields from Single-cell Quantities of mRNA in Standard Laboratory Reverse Transcriptase Reactions using Acoustic Microstreaming
1Florey Neuroscience Institutes and Centre for Neuroscience, University of Melbourne, 2Fluid Dynamics Group, CSIRO Materials Science and Engineering, 3Swinburne University of Technology, Faculty of Engineering and Industrial Sciences
We describe a novel method for increasing cDNA yield from single-cell quantities of mRNA in otherwise standard laboratory reverse transcription reactions. The novelty resides in the use of a micromixer, which utilizes the phenomenon of acoustic microstreaming, to mix fluids at microliter scales more effectively than shaking, vortexing or trituration.
JoVE General
Microcontact Printing of Proteins for Cell Biology
Department of Biomedical Engineering, Columbia University
Microcontact printing is used extensively to pattern proteins and other molecules on material surfaces. We demonstrate the basic steps of this process, stamping patterns of fibronectin onto glass.
JoVE General
Localized RNAi and Ectopic Gene Expression in the Medicinal Leech
1Division of Biological Sciences, University of California San Diego - UCSD, 2Department of Physics, University of California San Diego - UCSD
In this video, we show a procedure for an accurate biolistic delivery of reagents into live tissue with a novel miniature gene gun. We are knocking down the expression of the axon guidance molecule Netrin in leech embryos by delivering molecules of dsRNA into the ventral body wall and ganglia of single segments.
JoVE General
Measuring Diffusion Coefficients via Two-photon Fluorescence Recovery After Photobleaching
1Department of Physics and Astronomy, University of Rochester, 2Department of Biomedical Engineering, University of Rochester
In this article we will describe the procedure for measuring diffusion coefficients using multi-photon fluorescence recovery after photobleaching. We will begin by aligning the laser along the optical path to the sample and determining the proper experimental parameters, then continue generating and finally fitting fluorescence recovery curves.
JoVE Applied Physics
Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles
Department of Chemical Engineering, The Pennsylvania State University
We have used plasma enhanced chemical vapor deposition to deposit thin films ranging from a few nm to several 100 nm on nano-sized particles of various materials. We subsequently etch the core material to produce hollow nanoshells whose permeability is controlled by the thickness of the shell. We characterize the permeability of these coatings to small solutes and demonstrate that these barriers can provide sustained release of the core material over several days.
JoVE Applied Physics
Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
1Institute for Solid State Research, IFW-Dresden, 2Institute of Metal Physics of National Academy of Sciences of Ukraine, 3Diamond Light Source LTD, 4Department of Physics, University of Johannesburg, 5CNR-SPIN, and Dipartimento di Fisica "E. R. Caianiello", Università di Salerno, 6Institute of Physics of Complex Matter, École Polytechnique Fédérale de Lausanne
The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.
JoVE General
Dopamine Release at Individual Presynaptic Terminals Visualized with FFNs
1Departments of Neurology, Columbia University, 2Departments of Psychiatry and Pharmacology, Columbia University, 3Department of Chemistry, Columbia University, 4eMolecules, Inc., 5Departments of Neurology and Physiology, University of California School of Medicine, San Francisco, 6Division of Molecular Therapeutics, New York Psychiatric Institute
A new means to measure neurotransmission optically using fluorescent dopamine analogs.
JoVE Clinical and Translational Medicine
Quantitative Visualization and Detection of Skin Cancer Using Dynamic Thermal Imaging
Department of Mechanical Engineering, The Johns Hopkins University
We demonstrated that malignant pigmented lesions with increased metabolic activity generate quantifiable amounts of heat and the measurement of the transient thermal response of the skin to a cooling excitation allows quantitative identification of melanoma and other skin cancers (vs. non-proliferative nevi) at an early stage of the disease.
JoVE General
Direct Analysis of Single Cells by Mass Spectrometry at Atmospheric Pressure
Department of Chemistry, George Washington University
Single cell analysis is performed by mass spectrometry on plant and animal cells at atmospheric pressure by using a sharpened optical fiber to sample the cells for laser ablation electrospray ionization (LAESI) mass spectrometry.
JoVE Bioengineering
Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation
1Electrical Engineering Department, University of Washington, 2Division of Human Biology, Fred Hutchinson Cancer Research Center, 3Molecular and Cellular Biology Program, University of Washington, 4Clinical Research, Fred Hutchinson Cancer Research Center, 5Public Health Sciences, Fred Hutchinson Cancer Research Center
Plasmonic tweezers and photonic crystal nanostructures are shown to produce useful enhancements in the efficiency and orientation control of optically trapping micro- and nano-particles.
JoVE Bioengineering
Quantitative Locomotion Study of Freely Swimming Micro-organisms Using Laser Diffraction
1Physics & Astronomy Department, Vassar College, 2Biology Department, Vassar College
Microscopic organisms like the free-swimming nematode C. elegans, live and behave in a complex three-dimensional environment. We report on a novel approach that provides analysis of C. elegans using diffraction patterns. This approach consists of tracking the temporal periodicity of diffraction patterns generated by directing laser light through a cuvette.
JoVE General
Antifouling Self-assembled Monolayers on Microelectrodes for Patterning Biomolecules
1Department of Physics, Texas A&M University (TAMU), 2Department of Biomedical Engineering, Texas A&M University (TAMU)
We present a procedure for forming a poly(ethylene glycol) self-assembled monolayer (PEG-SAM) on a silicon substrate with gold microelectrodes. The PEG-SAM is formed in a single step and prevents biofouling on silicon and gold surfaces. Electrophoresis is then used for patterning biomolecules down to the nanoscale.
JoVE Immunology and Infection
Following Cell-fate in E. coli After Infection by Phage Lambda
1Department of Physics, University of Illinois at Urbana-Champaign, 2Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, 3Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine
This article describes the procedure for preparing a fluorescently-labeled version of bacteriophage lambda, infection of E. coli bacteria, following the infection outcome under the microscope, and analysis of infection results.
JoVE Bioengineering
Monitoring Protein Adsorption with Solid-state Nanopores
Department of Physics, Syracuse University
A method of using solid-state nanopores to monitor the non-specific adsorption of proteins onto an inorganic surface is described. The method employs the resistive-pulse principle, allowing for the adsorption to be probed in real-time and at the single-molecule level. Because the process of single protein adsorption is far from equilibrium, we propose the employment of parallel arrays of synthetic nanopores, enabling for the quantitative determination of the apparent first-order reaction rate constant of protein adsorption as well as and the Langmuir adsorption constant.
JoVE Applied Physics
A Method to Fabricate Disconnected Silver Nanostructures in 3D
1School of Engineering and Applied Sciences, Harvard University, 2Department of Physics, Harvard University
Femtosecond-laser direct-writing is frequently used to create three-dimensional (3D) patterns in polymers and glasses. However, patterning metals in 3D remains a challenge. We describe a method for fabricating silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm.
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