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Electromagnetic Fields: Fields representing the joint interplay of electric and magnetic forces.

Interictal High Frequency Oscillations Detected with Simultaneous Magnetoencephalography and Electroencephalography as Biomarker of Pediatric Epilepsy

1Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, 3Division of Epilepsy Surgery, Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, 4Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School

JoVE 54883


 Medicine

Assessing the Multiple Dimensions of Engagement to Characterize Learning: A Neurophysiological Perspective

1Department of Didactics, Université du Québec à Montréal, 2Department of IT and Tech3Lab, HEC Montreal, 3Department of Marketing and Tech3Lab, HEC Montreal, 4Department of Specialized Education, Université du Québec à Montréal

JoVE 52627


 Behavior

Inductance

JoVE 10303

Source: Yong P. Chen, PhD, Department of Physics & Astronomy, College of Science, Purdue University, West Lafayette, IN

This experiment will use inductive coils to demonstrate the concept of inductor and inductance. Magnetic induction will be demonstrated using a rod magnet inserted into or extracted away from the core of a coil to induce a transient electromotive force (emf) voltage in the coil, measured by a voltmeter. This experiment will also demonstrate the mutual inductance between two coils, where turning on or off a current flowing in a coil can induce an emf voltage in a second coil nearby. Finally, the experiment will demonstrate the self-inductance of a coil, when switching a current off induces an emf to light up a light bulb connected in parallel with the coil.


 Physics II

A Multimodal Imaging- and Stimulation-based Method of Evaluating Connectivity-related Brain Excitability in Patients with Epilepsy

1Department of Neurology, Harvard Medical School, 2Department of Neurology, Beth Israel Deaconess Medical Center, 3Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, 4Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 5Department of Neurology, Massachusetts General Hospital

JoVE 53727


 Medicine

Electric Charge in a Magnetic Field

JoVE 10133

Source: Andrew Duffy, PhD, Department of Physics, Boston University, Boston, MA

This experiment duplicates J.J. Thomson's famous experiment at the end of the 19th century, in which he measured the charge-to-mass ratio of the electron. In combination with Robert A. Millikan's oil-drop experiment a few years later that produced a value for the charge of the electron, the experiments enabled scientists to find, for the first time, both the mass and the charge of the electron, which are key parameters for the electron. Thomson was not able to measure the electron charge or the electron mass separately, but he was able to find their ratio. The same is true for this demonstration; although here there is the advantage of being able to look up the values for the magnitude of the charge on the electron(e) and the mass of the electron (me), which are now both known precisely.


 Physics II

Photoelectric Effect

JoVE 10413

Source: Yong P. Chen, PhD, Department of Physics && Astronomy, College of Science, Purdue University, West Lafayette, IN

Photoelectric effect refers to the emission of electrons from a metalwhen light is shining on it. In order for the electrons to be liberated from the metal, the frequency of the light needs to be sufficiently high such that the photons in the light have sufficient energy. This energy is proportional to the light frequency.The photoelectric effect provided the experimental evidence for the quantum of light that is known as photon. This experiment will demonstrate the photoelectric effect using a charged zinc metal subject to either a regular lamp light, or ultraviolet (UV) light with higher frequency and photon energy.The zinc plate will be connected to an electroscope, an instrument that can read the presence and relative amount of charges. The experiment will demonstrate that the UV light, but not the regular lamp, can discharge the negatively charged zinc by ejecting its excess electrons.Neither light source, however, can discharge positively charged zinc, consistent with the fact that electrons that are emitted in photoelectric effect.


 Physics II

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

JoVE 3390


 Bioengineering

Coordination Chemistry Complexes

JoVE 10179

Source: Laboratory of Dr. Neal Abrams — SUNY College of Environmental Science and Forestry

Transition metals are found everywhere from vitamin supplements to electroplating baths. Transition metals also make up the pigments in many paints and compose all minerals. Typically, transition metals are found in the cationic form since they readily oxidize, or lose electrons, and are surrounded by electron donors called ligands. These ligands do not form ionic or covalent bonds with the metal center, rather they take on a third type of bond known as coordinate-covalent. The coordinate-covalent bond between a ligand and a metal is dynamic, meaning that ligands are continuously exchanging and re-coordinating around the metal center. The identities of both the metal and the ligand dictates which ligands will bond preferentially over another. In addition, color and magnetic properties are also due to the types of complexes that are formed. The coordination compounds that form are analyzed using a variety of instruments and tools. This experiment explores why so many complexes are possible and uses a spectrochemical (color and chemical) method to help identify the type of coordination complex that forms.


 General Chemistry

Using Extraordinary Optical Transmission to Quantify Cardiac Biomarkers in Human Serum

1NUS Nanoscience and Nanotechnology Initiative, National University of Singapore, 2Cardiovascular Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, 3Department of Electrical and Computer Engineering, National University of Singapore, 4Institute of Materials Research Engineering, A*STAR (Agency for Science, Technology and Research)

Video Coming Soon

JoVE 55597


 JoVE In-Press

Nuclear Magnetic Resonance (NMR) Spectroscopy

JoVE 5680

Source: Laboratory of Dr. Henrik Sundén – Chalmers University of Technology

Nuclear magnetic resonance (NMR) spectroscopy is a vital analysis technique for organic chemists. With the help of NMR, the work in the organic lab has been facilitated tremendously. Not only can it provide information about the structure of a molecule but also determine the content and purity of a sample. Compared with other commonly encountered techniques for organic chemists — such as thermal analysis and mass spectrometry (MS) — NMR is a non-destructive method that is valuable when recovery of the sample is important. One of the most frequently used NMR techniques for an organic chemist is proton (1H) NMR. The protons present in a molecule will behave differently depending on its surrounding chemical environment, making it possible to elucidate its structure. Moreover, it is possible to monitor the completion of a reaction by comparing NMR spectra of the starting material to that of the final product. This video exemplifies how NMR spectroscopy can be used in the everyday work of an organic chemist. The following will be shown: i) preparation of an NMR sample. ii) Using 1H NMR to monitor a reaction. iii) Identifying the product obtained from


 Organic Chemistry

Raman Spectroscopy for Chemical Analysis

JoVE 5701

Source: Laboratory of Dr. Ryoichi Ishihara — Delft University of Technology

Raman spectroscopy is a technique for analyzing vibrational and other low frequency modes in a system. In chemistry it is used to identify molecules by their Raman fingerprint. In solid-state physics it is used to characterize materials, and more specifically to investigate their crystal structure or crystallinity. Compared to other techniques for investigating the crystal structure (e.g. transmission electron microscope and x-ray diffraction) Raman micro-spectroscopy is non-destructive, generally requires no sample preparation, and can be performed on small sample volumes. For performing Raman spectroscopy a monochromatic laser is shone on a sample. If required the sample can be coated by a transparent layer which is not Raman active (e.g., SiO2) or placed in DI water. The electromagnetic radiation (typically in the near infrared, visible, or near ultraviolet range) emitted from the sample is collected, the laser wavelength is filtered out (e.g., by a notch or bandpass filter), and the resulting light is sent through a monochromator (e.g., a grating) to a CCD detector. Using this, the inelastic scattered light, originating from Raman scattering, can be captured and used to construct the Raman spectrum o


 Analytical Chemistry

An Introduction to Cognition

JoVE 5419

Cognition encompasses mental processes such as memory, perception, decision-making reasoning and language. Cognitive scientists are using a combination of behavioral and neuropsychological techniques to investigate the underlying neural substrates of cognition. They are interested in understanding how information is perceived, processed and how does it affect the final execution of behaviors. With this knowledge, researchers hope to develop new treatments for individuals with cognitive impairments. JoVE's introduction to cognition reviews several components of this phenomenon, such as perception, attention, language comprehension, etc. Key questions in the field of cognition will be discussed along with specific methods currently being used to answer these questions. Finally, specific studies that investigate different aspects of cognition using tools like functional Magnetic Resonance Imaging (fMRI) or Transcranial magnetic stimulation (TMS) will be explained.


 Behavioral Science

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