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Partial Pressure: The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Gas Absorber

JoVE 10436

Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA

Gas absorbers are used to remove contaminants from gas streams. Multiple designs are used to accomplish this objective1. A packed bed column uses gas and liquid streams running counter to each other in a column packed with loose packing materials, such as ceramics, metals, and plastics, or structured packing1. The packed bed uses surface area created by the packing to create a maximum amount of efficient contact between the two phases1. The systems are low maintenance and can handle corrosive materials with high mass transfer rates1. Spray columns are another type of absorber, which uses constant direct contact between the two phases, with gas moving up and liquid being sprayed down into the gas flow1. This system only has one stage and poor mass transfer rates, but is very effective for solutes with high liquid solubility1. The goal of this experiment is to determine how variables including gas flow rate, water flow rate, and carbon dioxide concentration affect the overall mass transfer coefficient in a gas absorber. Understand


 Chemical Engineering

Synthesis Of A Ti(III) Metallocene Using Schlenk Line Technique

JoVE 10428

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

Inorganic chemists often work with highly air- and water-sensitive compounds. The two most common and practical methods for air-free synthesis utilize either Schlenk lines or gloveboxes. This experiment will demonstrate how to perform simple manipulations on a Schlenk line with a focus on solvent preparation and transfer. Through the synthesis of a reactive Ti(III) metallocene complex, we will demonstrate a new, simple method to degas solvent as well as how to transfer solvent by cannula and by syringe on a Schlenk line. The synthesis of a Ti(III) metallocene compound 3 is shown in Figure 1.1 Compound 3 is highly reactive with O2, (see oxidation of compound 3 to Ti(IV) metallocene 4 shown in Figure 1). Therefore, it is important to run the synthesis under anaerobic conditions. The synthesis of target compound 3 can be monitored visually and progresses through one additional color change before arriving at the desired product, which is blue in color. If during the experiment there is an observed color change from blue to yellow (or green = blue + yellow), this is an indication that O2 entered the flask and that undesired oxidation of compound 3 to


 Inorganic Chemistry

A Model to Simulate Clinically Relevant Hypoxia in Humans

1Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Bonn, 2Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, 3Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, 4Institute of Physiology 2, University of Bonn

JoVE 54933


 Medicine

Cerebral Blood Oxygenation Measurement Based on Oxygen-dependent Quenching of Phosphorescence

1Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 2Department of Biochemistry and Biophysics, University of Pennsylvania, 3Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, 4Departments of Neurosciences and Radiology, University of California

JoVE 1694


 Neuroscience

In Vivo EPR Assessment of pH, pO2, Redox Status, and Concentrations of Phosphate and Glutathione in the Tumor Microenvironment

1In Vivo Multifunctional Magnetic Resonance center, Robert C. Byrd Health Sciences Center, West Virginia University, 2Department of Biochemistry, West Virginia University School of Medicine, 3Department of Microbiology, Immunology & Cell Biology, West Virginia University School of Medicine

JoVE 56624


 Cancer Research

Isolation of CD146+ Resident Lung Mesenchymal Stromal Cells from Rat Lungs

1Sinclair Centre for Regenerative Medicine, Ottawa Hospital Research Institute, 2University of Ottawa, 3Department of Neonatology and Pediatric Critical Care Medicine, Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, 4DFG Research Center and Cluster of Excellence for Regenerative Therapies (CRTD), Technische Universität, Dresden, 5Children's Hospital of Eastern Ontario Research Institute

JoVE 53782


 Biology

Making Record-efficiency SnS Solar Cells by Thermal Evaporation and Atomic Layer Deposition

1Department of Mechanical Engineering, Massachusetts Institute of Technology, 2Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology, 3School of Engineering and Applied Sciences, Harvard University, 4Department of Materials Science and Engineering, Massachusetts Institute of Technology, 5Department of Chemistry & Chemical Biology, Harvard University

JoVE 52705


 Engineering

Le Châtelier's Principle

JoVE 10138

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


 General Chemistry

Functional Human Liver Preservation and Recovery by Means of Subnormothermic Machine Perfusion

1Center for Engineering in Medicine, Dept. of Surgery, Massachusetts General Hospital, Harvard Medical School, 2Transplant Center, Dept. of Surgery, Massachusetts General Hospital, Harvard Medical School, 3Section of Hepatobiliary Surgery and Liver Transplantation, Department of Surgery, University Medical Center Groningen, University of Groningen

JoVE 52777


 Medicine

Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise

1Division of Pulmonary Medicine, University of Alberta, 2Faculty of Physical Education and Recreation, University of Alberta, 3Divisions of Critical Care and Cardiology, University of Alberta, 4Faculty of Rehabilitation Medicine, University of Alberta, 5G.F. MacDonald Centre for Lung Health

JoVE 54949


 Medicine

Degassing Liquids with Freeze-Pump-Thaw Cycling

JoVE 5639

Source: Laboratory of Dr. Neil Branda — Simon Fraser University

Degassing refers to the process by which dissolved gases are removed from a liquid. The presence of dissolved gases such as oxygen or carbon dioxide can impede chemical reactions that utilize sensitive reagents, interfere with spectroscopic measurements, or can induce unwanted bubble formation. A number of different techniques are available for degassing liquids; some of these include heating, ultrasonic agitation, chemical removal of gases, substitution with inert gas by bubbling and freeze-pump-thaw cycling. Freeze-pump-thaw cycling is a common and effective method for small scale degassing, and will be demonstrated here in more detail.


 Organic Chemistry

Neurovascular Network Explorer 2.0: A Simple Tool for Exploring and Sharing a Database of Optogenetically-evoked Vasomotion in Mouse Cortex In Vivo

1Department of Radiology, University of California, San Diego, 2Central European Institute of Technology, Brno University of Technology, 3Department of Neurosciences, University of California, San Diego, 4Department of Physics, John Carroll University, 5Department of Biomedical Engineering, Boston University, 6Bioengineering Undergraduate Program, University of California, San Diego, 7Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, 8Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School

JoVE 57214


 Neuroscience

Synthesis, Cellular Delivery and In vivo Application of Dendrimer-based pH Sensors

1Institute for Complex Molecular Systems & Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology & NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, 2NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR & IIT@NEST, Center for Nanotechnology Innovation, 3NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, 4IIT@NEST, Center for Nanotechnology Innovation

JoVE 50545


 Chemistry

Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities

1Department of Physics, University of California at Berkeley, 2Department of Chemistry, University of California at Berkeley, 3Department of Chemical and Biomolecular Engineering, University of California at Berkeley, 4National Institute for Materials Science (Japan), 5Materials Sciences Division, Lawrence Berkeley National Laboratory, 6Kavli Energy NanoSciences Institute, University of California at Berkeley and Lawrence Berkeley National Laboratory

JoVE 52711


 Engineering

Using Fiberless, Wearable fNIRS to Monitor Brain Activity in Real-world Cognitive Tasks

1Department of Medical Physics and Biomedical Engineering, Malet Place Engineering Building, University College London, 2Infrared Imaging Lab, Institute for Advanced Biomedical Technology (ITAB), Department of Neuroscience, Imaging and Clinical Sciences, University of Chieti-Pescara, 3Institute of Cognitive Neuroscience, Alexandra House, University College London

JoVE 53336


 Behavior

Detection of Microregional Hypoxia in Mouse Cerebral Cortex by Two-photon Imaging of Endogenous NADH Fluorescence

1Department of Microbiology and Immunology, University of Rochester Medical Center, 2Center for Neural Development and Disease, University of Rochester Medical Center, 3Deptartment of Neurology, Center for Neural Development and Disease, University of Rochester Medical Center

JoVE 3466


 Neuroscience

Construction and Setup of a Bench-scale Algal Photosynthetic Bioreactor with Temperature, Light, and pH Monitoring for Kinetic Growth Tests

1Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 2Department of Plant and Microbial Biology, North Carolina State University

JoVE 55545


 Bioengineering

Matrix-assisted Autologous Chondrocyte Transplantation for Remodeling and Repair of Chondral Defects in a Rabbit Model

1Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar der Technischen Universität München, 2Department of Radiology, Klinikum rechts der Isar der Technischen Universität München, 3Institute of Experimental Oncology and Therapy Research, Klinikum rechts der Isar der Technischen Universität München, 4Department of Radiology, Uniklinik Köln

JoVE 4422


 Medicine

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