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Hemoglobin A: Normal adult human hemoglobin. The globin moiety consists of two alpha and two beta chains.
 Science Education: Essentials of Analytical Chemistry

Ion-Exchange Chromatography

JoVE Science Education

Source: Laboratory of Dr. B. Jill Venton - University of Virginia

Ion-exchange chromatography is a type of chromatography that separates analytes based on charge. A column is used that is filled with a charged stationary phase on a solid support, called an ion-exchange resin. Strong cation-exchange chromatography preferentially separates out cations by using a negatively-charged resin while strong anion-exchange chromatography preferentially selects out anions by using a positively-charged resin. This type of chromatography is popular for sample preparation, for example in the cleanup of proteins or nucleic acid samples. Ion-exchange chromatography is a two-step process. In the first step, the sample is loaded onto the column in a loading buffer. The binding of the charged sample to the column resin is based on ionic interactions of the resin to attract the sample of the opposite charge. Thus, charged samples of opposite polarity to the resin are strongly bound. Other molecules that are not charged or are of the opposite charge are not bound and are washed through the column. The second step is to elute the analyte that is bound to the resin. This is accomplished with a salt gradient, where the amount of salt in the buffer is slowly increased. Fractions are collected at the end of the column as

 JoVE Medicine

Non-invasive Optical Measurement of Cerebral Metabolism and Hemodynamics in Infants

1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, 2Lab. PALM, Université de Caen Basse-Normandie, 3Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children's Hospital, Harvard Medical School, 4ISS, INC.

JoVE 4379

 JoVE Medicine

Diffuse Optical Spectroscopy for the Quantitative Assessment of Acute Ionizing Radiation Induced Skin Toxicity Using a Mouse Model

1Department of Radiation Oncology, University of Toronto, 2Department of Physics, Ryerson University, 3Department of Medical Biophysics, University of Toronto, 4Ontario Cancer Institute / Campbell Family Institute for Cancer Research

JoVE 53573

 JoVE Immunology and Infection

Antigens Protected Functional Red Blood Cells By The Membrane Grafting Of Compact Hyperbranched Polyglycerols

1Centre for Blood Research, University of British Columbia, 2Department of Pathology and Laboratory Medicine, University of British Columbia, 3Canadian Blood Services, University of British Columbia, 4Department of Chemistry, Life Sciences Centre, University of British Columbia

JoVE 50075

 JoVE Immunology and Infection

Ex Vivo Red Blood Cell Hemolysis Assay for the Evaluation of pH-responsive Endosomolytic Agents for Cytosolic Delivery of Biomacromolecular Drugs

1Department of Biomedical Engineering, Vanderbilt University, 2Vanderbilt Institute for Nanoscale Science & Engineering, Vanderbilt University, 3Interdisciplinary Materials Science Program, Vanderbilt University, 4Monroe Carell Jr. Children's Hospital, Vanderbilt University Medical Center, 5Department of Chemical & Biomolecular Engineering, Vanderbilt University, 6Department of Cancer Biology, Vanderbilt University

JoVE 50166

 Science Education: Essentials of General Chemistry

Le Châtelier's Principle

JoVE Science Education

Source: Laboratory of Dr. Lynne O'Connell — Boston College

When the conditions of a system at equilibrium are altered, the system responds in such a way as to maintain the equilibrium. In 1888, Henri-Lewis Le Châtelier described this phenomenon in a principle that states, "When a change in temperature, pressure, or concentration disturbs a system in chemical equilibrium, the change will be counteracted by an alteration in the equilibrium composition." This experiment demonstrates Le Châtelier's principle at work in a reversible reaction between iron(III) ion and thiocyanate ion, which produces iron(III) thiocyante ion: Fe3+(aq) + SCN- (aq) FeSCN2+ (aq) The concentration of one of the ions is altered either by directly adding a quantity of one ion to the solution or by selectively removing an ion from the solution through formation of an insoluble salt. Observations of color changes indicate whether the equilibrium has shifted to favor formation of the products or the reactants. In addition, the effect of a temperature change on the solution at equilibrium can be obs

 Science Education: Essentials of Physical Examinations I

Measuring Vital Signs

JoVE Science Education

Source: Meghan Fashjian, ACNP-BC, Beth Israel Deaconess Medical Center, Boston MA

The vital signs are objective measurements of a patient's clinical status. There are five commonly accepted vital signs: blood pressure, heart rate, temperature, respiratory rate, and oxygen saturation. In many practices, pain is considered the sixth vital sign and should regularly be documented in the same location as the other vital signs. However, the pain scale is a subjective measurement and, therefore, has a different value according to each individual patient. The vital signs assessment includes estimation of heart rate, blood pressure (demonstrated in a separate video), respiratory rate, temperature, oxygen saturation, and the presence and severity of pain. The accepted ranges for vital signs are: heart rate (HR), 50-80 beats per minute (bpm); respiratory rate (RR), 14-20 bpm; oxygen saturation (SaO2), > 92%; and average oral temperature, ~98.6 °F (37 °C) (average rectal and tympanic temperatures are ~1° higher, and axillary temperature is ~1° lower compared to the average oral temperature). Vital signs serve as the first clue that something may be amiss with a patient, especially if the patient is unable to communicate. Although there are

 JoVE Behavior

fMRI Validation of fNIRS Measurements During a Naturalistic Task

1Department of Psychiatry, Yale School of Medicine, 2Department of Electronics and Bioinformatics, Meiji University, 3Department of Histology and Neurobiology, Dokkyo Medical University School of Medicine, 4ADAM Center, Department of Physical Therapy, Movement and Rehabilitation Sciences, Northeastern University, 5Department of Neurobiology, Yale School of Medicine

JoVE 52116

 JoVE Medicine

Experimental and Imaging Techniques for Examining Fibrin Clot Structures in Normal and Diseased States

1Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University School of Medicine, 2Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, 3George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology

JoVE 52019

 JoVE Developmental Biology

Understanding Early Organogenesis Using a Simplified In Situ Hybridization Protocol in Xenopus

1Developmental and Stem Cell Biology, Hospital for Sick Children, 2Children's Health Research Institute, University of Western Ontario, 3Department of Physiology and Pharmacology, University of Western Ontario, 4Neurosciences and Mental Health, Hospital for Sick Children, 5Department of Paediatrics, University of Western Ontario

JoVE 51526

 JoVE Medicine

A Multicenter MRI Protocol for the Evaluation and Quantification of Deep Vein Thrombosis

1Department of Radiology, Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, 2Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, 3Daiichi Sankyo Pharma Development

JoVE 52761

 JoVE Medicine

Flexible Colonoscopy in Mice to Evaluate the Severity of Colitis and Colorectal Tumors Using a Validated Endoscopic Scoring System

1Division of Gastroenterology, Case Western Reserve University School of Medicine, Cleveland, 2Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, 3Digestive Health Research Center, Case Western Reserve University School of Medicine, Cleveland

JoVE 50843

 Science Education: Essentials of General Chemistry

Coordination Chemistry Complexes

JoVE Science Education

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.

 JoVE Immunology and Infection

Separation of Plasmodium falciparum Late Stage-infected Erythrocytes by Magnetic Means

1Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), 2Acharya Nagarjuna University, 3Departamento de Medios y Creativo, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP)

JoVE 50342

 JoVE Bioengineering

Gene Transfection toward Spheroid Cells on Micropatterned Culture Plates for Genetically-modified Cell Transplantation

1Graduate School of Medicine, Laboratory of Clinical Biotechnology, The University of Tokyo, 2Graduate School of Engineering, Department of Materials Engineering, The University of Tokyo, 3Graduate School of Engineering, Department of Bioengineering, The University of Tokyo

JoVE 52384

 JoVE Immunology and Infection

Rapid Identification of Gram Negative Bacteria from Blood Culture Broth Using MALDI-TOF Mass Spectrometry

1Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, Westmead Hospital, 2Centre for Research Excellence in Critical Infection, Westmead Millennium Institute, Westmead Hospital, 3Sydney Emerging Infectious Diseases Institute, University of Sydney, Westmead Hospital

JoVE 51663

 Science Education: Essentials of Neuroscience

fMRI: Functional Magnetic Resonance Imaging

JoVE Science Education

Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique used to investigate human brain function and cognition in both healthy individuals and populations with abnormal brain states. Functional MRI utilizes a magnetic resonance signal to detect changes in blood flow that are coupled to neuronal activation when a specific task is performed. This is possible because hemoglobin within the blood has different magnetic properties depending on whether or not it is bound to oxygen. When a certain task is performed, there is an influx of oxygenated blood to brain regions responsible for that function, and this influx can then be detected with specific MRI scan parameters. This phenomenon is termed the blood oxygen level ependent (BOLD) effect, and can be used to create maps of brain activity. This video begins with a brief overview of how MRI and fMRI signal is obtained. Then, basic experimental design is reviewed, which involves first setting up a stimulus presentation that is specifically designed to test the function that will be mapped. Next, key steps involved in performing the fMRI scan are introduced, including subject safety and setting up at the scanner. Commonly used steps for data processing are then presented, including pre-processing and statistical analysis with the general linear

 JoVE Medicine

A New Murine Model of Endovascular Aortic Aneurysm Repair

1INSERM U698 Cardiovascular Remodelling, Hôpital X. Bichat, AP-HP, Paris, 2Bio-Ingénierie des Polymères Cardiovasculaires (BPC), Institut Galilée - Université Paris 13, Paris, France, 3Service de Chirurgie Vasculaire, Hôpital Henri Mondor, AP-HP, Université Paris-Est Creteil, 4Ecole de chirurgie de l'assistance publique des hôpitaux de Paris, 5Service de Chirurgie Cardiaque et Vasculaire, Hôpital Européen Georges Pompidou, AP-HP, Université René Descartes

JoVE 50740

 JoVE Medicine

Ex Situ Normothermic Machine Perfusion of Donor Livers

1Section of Hepato-Pancreato-Biliary Surgery and Liver Transplantation, University of Groningen, University Medical Center Groningen, 2Surgical Research Laboratory, Department of Surgery, University of Groningen, University Medical Center Groningen, 3Center of Engineering in Medicine/Surgical Services, Massachusetts General Hospital, Harvard Medical School, and Shriners Burns Hospital, 4Division of Transplantation, Department of Surgery, Massachusetts General Hospital, Harvard Medical School

JoVE 52688

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