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Freeze Drying: Method of tissue preparation in which the tissue specimen is frozen and then dehydrated at low temperature in a high vacuum. This method is also used for dehydrating pharmaceutical and food products.

States of Water

JoVE 10668

Water exists in three main states: solid (ice), liquid, and gas (steam). The state water is in depends on the intermolecular forces that draw water molecules together and the kinetic energy that pulls them apart.

Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than it is in its liquid state. This is because each water molecule is capable of bonding with four molecules, forming a spaced, tetrahedral organization. This characteristic of water allows ice to float. Without floating ice, bodies of water would freeze from the bottom up, killing aquatic life. When kinetic energy is applied to ice in the form of heat, ice melts into liquid water. In this state, bonds between water molecules constantly break and form again. When ice melts, the temperature of the water remains at the melting point until the whole volume is liquid. Only then will the water temperature increase beyond the melting point. As kinetic energy overpowers intermolecular forces, liquid water (or even ice) turns into a gas. The process of generating steam from liquid water is called vaporization. Increases in kinetic energy can occur within the sample, as with boiling, or can happen at the surface when water evaporates. The process by which a gas is generated directly from a solid, witho

 Core: Chemistry of Life

Differential Scanning Calorimetry

JoVE 10487

Source: Danielle N. Beatty and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT


Differential scanning calorimetry (DSC) is an important measurement to characterize thermal properties of materials. DSC is used primarily to calculate the amount of heat stored in a material as it…

 Materials Engineering

Using Differential Scanning Calorimetry to Measure Changes in Enthalpy

JoVE 5559

Source: Laboratory of Dr. Terry Tritt — Clemson University


Differential Scanning Calorimetry (DSC) is a method of thermodynamic analysis based on heat-flux method, wherein a sample material (enclosed in a pan) and an empty reference pan are subjected to identical temperature conditions. The energy difference that is required to…

 General Chemistry

Proper Operation of Vacuum Based Equipment

JoVE 10377

Source: Robert M. Rioux, Ajay Sathe & Zhifeng Chen, Pennsylvania State University, University Park, PA


Vacuum is required for a number of laboratory procedures. This is most routinely achieved in the laboratory by the use of vacuum pumps. In addition to working at low pressures, vacuum pumps can also be used to enable…

 Lab Safety

Purification of Ferrocene by Sublimation

JoVE 10429

Source: Tamara M. Powers, Department of Chemistry, Texas A&M University 


Sublimation, the direct phase transition of a solid into a gas without first becoming a liquid, takes place at temperatures and pressures lower than that of the compound's triple point (Figure 1).The process of sublimation can be utilized …

 Inorganic Chemistry

Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures

1Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 2Department of Soil, Water and Environmental Science, University of Arizona, 3Department of Earth Ocean and Atmospheric Sciences, Florida State University, 4Bruker Daltonics Inc., 5Biological Sciences Division, Pacific Northwest National Laboratory

JoVE 59035

 Environment

Biosynthesis of a Flavonol from a Flavanone by Establishing a One-pot Bienzymatic Cascade

1College of Bioscience and Biotechnology, Yangzhou University, 2Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, 3Joint International Research Laboratory of Agriculture & Agri-Product Safety, Yangzhou University, 4Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, 5The Testing Center, Yangzhou University

JoVE 59336

 Biochemistry

Treatment with Vancomycin Loaded Calcium Sulphate and Autogenous Bone in an Improved Rabbit Model of Bone Infection

1Department of Medicine, Zhejiang Academy of Traditional Chinese Medicine, 2Department of Orthopaedic Surgery, Tongde Hospital of Zhejiang Province, 3Institute of Orthopaedics and Traumatology, First Affiliated Hospital of Zhejiang Chinese Medical University, 4Department of Clinical Laboratory, Tongde Hospital of Zhejiang Province

JoVE 57294

 Medicine

Microhoneycomb Monoliths Prepared by the Unidirectional Freeze-drying of Cellulose Nanofiber Based Sols: Method and Extensions

1Engineering Laboratory for Functionalized Carbon Materials and Shenzhen Key Laboratory for Graphene-based Materials, Graduate School at Shenzhen, Tsinghua University, 2School of Materials Science and Engineering, Tsinghua University, 3Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 4Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, 5School of Chemical Engineering and Technology, Tianjin University

JoVE 57144

 Bioengineering

Synthesis of Functionalized 10-nm Polymer-coated Gold Particles for Endothelium Targeting and Drug Delivery

1Department of Chemical Engineering, Northeastern University, 2Nanomedicine Science and Technology Center, Northeastern University, 3Department of Physics, Northeastern University, 4Departments of Bioengineering, Northeastern University, 5Department of Neuroscience, Albert Einstein College of Medicine

JoVE 56760

 Bioengineering

Extraction and Purification of Polyphenols from Freeze-dried Berry Powder for the Treatment of Vascular Smooth Muscle Cells In Vitro

1Department of Dietetics and Nutrition, University of Arkansas for Medical Sciences, 2Department of Nutrition, Food and Exercise Sciences, Florida State University, 3Center for Advancing Exercise and Nutrition Research on Aging (CAENRA), Florida State University

JoVE 55605

 Chemistry

A New Method for Qualitative Multi-scale Analysis of Bacterial Biofilms on Filamentous Fungal Colonies Using Confocal and Electron Microscopy

1Interactions Arbres – Microorganismes, UMR1136, INRA Université de Lorraine, 2Ecologie et Ecophysiologie Forestières - PTEF, UMR 1137, INRA Université de Lorraine, 3Biosciences Division, Oak Ridge National Laboratory

JoVE 54771

 Immunology and Infection

A Lipid Extraction and Analysis Method for Characterizing Soil Microbes in Experiments with Many Samples

1Department of Agronomy and Great Lakes Bioenergy Research Center, University of Wisconsin - Madison, 2Department of Soil Science, University of Wisconsin - Madison, 3Department of Soil, Water, and Climate, University of Minnesota, 4Faculty of Science and Engineering, Curtin University

JoVE 55310

 Environment

Extraction and Analysis of Microbial Phospholipid Fatty Acids in Soils

1Department of Renewable Resources, University of Alberta, 2Department of Science, Augustana Faculty, University of Alberta, 3Laboratoire Génie Civil et géo-Environnement, Université de Lille, 4Department of Earth and Environmental Sciences, Mount Royal University, 5Forest Ecology & Production, Great Lakes Forestry Centre, Natural Resources Canada

JoVE 54360

 Environment

Functionalization of Single-walled Carbon Nanotubes with Thermo-reversible Block Copolymers and Characterization by Small-angle Neutron Scattering

1Biology and Soft Matter Division, Neutron Science Directorate, Oak Ridge National Laboratory, 2Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 3Department of Polymer Science and Engineering, Pusan National University, 4Jülich Center for Neutron Science, Forschungszentrum Jülich

JoVE 53969

 Chemistry

Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA)

1Department of Geography, University of Zurich, 2Department of Earth and Ocean Sciences, University of South Carolina, 3Department of Earth Sciences, ETH Zurich, 4Laboratory of Ion Beam Physics, ETH Zurich, 5Department of Geological Sciences, Stockholm University

JoVE 53922

 Chemistry
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