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October, 2006
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Hydrogen Bonding: A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.


JoVE 10673

Cohesion is the attraction between molecules of the same type - such as water molecules. The partially charged negative oxygen of one water molecule binds to the partially charged positive hydrogen of a second water molecule via hydrogen bonding. Each water molecule can form up to four hydrogen bonds with other water molecules.

On a surface, when multiple water molecules come together through cohesion, a droplet is formed. Water does not typically spread out across the surface. This is because the water molecules are more attracted to each other than to molecules that make up the surface or the surrounding air. Surface tension results from cohesion. Pond skaters, also known as water striders, are insects that use this phenomenon to walk on water. Surface tension occurs at the interface between water and air (i.e., the water’s surface). Again, water molecules are more attracted to each other than they are to molecules in the air. Thus, the water molecules at the surface form bonds with neighboring water molecules beside and below them. Since the surface water molecules cannot form bonds with other water molecules on one side (the side next to the air), they form stronger bonds with their neighboring water molecules. The strongly-bonded molecules have a compressed surface area, creating spherical droplets of water molecules. The high surface tension of

 Core: Chemistry of Life

The DNA Helix

JoVE 10784

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most viruses. DNA is composed of two strands of nucleotides that wind around each other to form a double helix. The discovery of the structure of DNA occurred incrementally over nearly a century, representing one of the most famous and captivating stories in the history of science. Each strand of DNA consists of subunits called nucleotides that contain the sugar deoxyribose, a phosphate group, and one of four nitrogen-containing bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Adenine and guanine are members of a larger class of chemicals called purines that all contain two-ringed structures. Cytosine and thymine belong to a group of single-ringed structures called pyrimidines. Adjacent nucleotides in the same strand are covalently linked by phosphodiester bonds. The two strands of nucleotides are held together by hydrogen bonds, in which the adenines in one strand pair with thymines at the same position in the other strand, and the cytosines in one strand pair with guanines in the same position in the other strand. This hydrogen bonding is made possible by the antiparallel arrangement of the two DNA strands, in which the 5’ and 3’ ends of the strands are oriented in opposite directions. Withou

 Core: DNA Structure and Function

Two-Dimensional Gel Electrophoresis

JoVE 5686

Two-dimensional gel electrophoresis (2DGE) is a technique that can resolve thousands of biomolecules from a mixture. This technique involves two distinct separation methods that have been coupled together: isoelectric focusing (IEF) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). This physically separates compounds across two axes of a gel by their isoelectric points…


Ideal Gas Law

JoVE 5537

Source: Laboratory of Dr. Andreas Züttel - Swiss Federal Laboratories for Materials Science and Technology

The ideal gas law describes the behavior of most common gases at near-ambient conditions and the tendency of all chemical matter in the dilute limit. It is a fundamental relationship between three measurable macroscopic system…

 General Chemistry

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

1Organic Chemistry Institute and CeNTech, Westfälische Wilhelms-Universität Münster, 2Laboratory of Macromolecular and Organic Chemistry, Institute for Complex Molecular Systems, Eindhoven University of Technology, 3Laboratory of Materials and Interface Chemistry and Soft Matter Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology

JoVE 3975


Expression, Purification, Crystallization, and Enzyme Assays of Fumarylacetoacetate Hydrolase Domain-Containing Proteins

1Research Institute for Biomedical Aging Research, University of Innsbruck Austria, 2Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck Austria, 3Division of Genetic Epidemiology, Medical University of Innsbruck Austria, 4Faculty of Chemistry, Department of Organic Chemistry, University of Vienna Austria

JoVE 59729


Fabrication of Extracellular Matrix-derived Foams and Microcarriers as Tissue-specific Cell Culture and Delivery Platforms

1Biomedical Engineering Graduate Program, The University of Western Ontario, 2Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, 3Department of Chemical Engineering, Queen's University, 4Department of Chemical & Biochemical Engineering, Faculty of Engineering, The University of Western Ontario

JoVE 55436


Synthesis of Thermogelling Poly(N-isopropylacrylamide)-graft-chondroitin Sulfate Composites with Alginate Microparticles for Tissue Engineering

1Department of Chemical Engineering, Rowan University, 2Department of Biological Sciences, Rowan University, 3Department of Biomedical Engineering, Drexel University

JoVE 53704


Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper

1Testing and Technical Services, Plant Operations, United States Government Publishing Office, 2Materials Measurement Laboratory, National Institute of Standards and Technology, 3Nanoscale Device Characterization Division, Physical Measurement Laboratory, National Institute of Standards and Technology, 4College of Pharmacy, University of South Florida

JoVE 59991


Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts

1Department of Applied Chemistry, The University of Tokyo, 2Clean Energy Research Center, University of Yamanashi, 3Biofunctional Catalyst Research Team, RIKEN Center for Sustainable Resource Science, 4Earth-Life Science Institute (ELSI), Tokyo Institute of Technology, 5Department of Materials Science and Engineering, Tokyo Institute of Technology, 6National Institute for Materials Science

JoVE 58072


A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites

1School of Public Health of Southeast University, Laboratory of Environment and Biosafety Research Institute of Southeast University in Suzhou, 2Key Laboratory of Child Development and Learning Science (Ministry of Education), School of Biological Science & Medical Engineering, Southeast University, 3School of Public Health, Tianjin Medical University, 4British Columbia Academy, Nanjing Foreign Language School

JoVE 56445


From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

1Laboratory of Supramolecular and Bio-Nanomaterials (SBNLab), Department of Chemistry, Materials, and Chemical Engineering "Giulio Natta", Politecnico di Milano, 2Department of Chemistry, University of York, 3Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials, and Chemical Engineering "Giulio Natta", Politecnico di Milano

JoVE 55636


Magnetic and Thermal-sensitive Poly(N-isopropylacrylamide)-based Microgels for Magnetically Triggered Controlled Release

1Institute of Polymer Science and Engineering, National Taiwan University, 2Department of Materials Engineering, Ming Chi University of Technology, 3Department of Metallurgy and Materials Engineering, Bandung Institute of Technology and Science, 4Department of Chemical Engineering, National Taiwan University, 5Department of Materials Science and Engineering, National Taiwan University

JoVE 55648


An Injectable and Drug-loaded Supramolecular Hydrogel for Local Catheter Injection into the Pig Heart

1Institute for Complex Molecular Systems, Department of Biomedical Engineering, Laboratory of Chemical Biology, Eindhoven University of Technology, 2Department of Cardiology, Division Heart and Lungs, Interuniversity Cardiology Institute of the Netherlands (ICIN), University Medical Center Utrecht

JoVE 52450

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