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Inorganic Pyrophosphatase: An enzyme which catalyzes the hydrolysis of diphosphate (Diphosphates) into inorganic phosphate. The hydrolysis of pyrophosphate is coupled to the transport of Hydrogen ions across a membrane.

Optimized Protocol for the Extraction of Proteins from the Human Mitral Valve

1Centro Cardiologico Monzino IRCCS, 2Cardiovascular Tissue Bank of Milan, Centro Cardiologico Monzino IRCCS, 3Department of Clinical Sciences and Community Health, Cardiovascular Section, University of Milan, 4Department of Cardiovascular Disease, Development and Innovation Cardiac Surgery Unit, Centro Cardiologico Monzino IRCCS

JoVE 55762


 Biochemistry

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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

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JoVE 56624


 JoVE In-Press

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Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films

1Joint Center for Artificial Photosynthesis, Chemical Sciences Division, Lawrence Berkeley National Laboratory, 2Electrical Engineering and Computer Sciences, University of California, Berkeley, 3Materials Science Division, Lawrence Berkeley National Laboratory, 4Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, 5Department of Physics, Graduate School of Nanotechnology, University of Trieste, 6TASC Laboratory, IOM-CNR - Istituto Officina dei Materiali, 7Department of Chemistry, University of California, Berkeley, 8Materials Science and Engineering, University of California, Berkeley, 9Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory

JoVE 55404


 Chemistry

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Application of Group Theory to IR Spectroscopy

JoVE 10442

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

Metal carbonyl complexes are used as metal precursors for the synthesis of organometallic complexes as well as catalysts. Infrared (IR) spectroscopy is one of the most utilized and informative characterization methods of CO containing compounds. Group theory, or the use of mathematics to describe the symmetry of a molecule, provides a method to predict the number of IR active C-O vibrational modes within a molecule. Experimentally observing the number of C-O stretches in the IR is a direct method to establish the geometry and structure of the metal carbonyl complex. In this video, we will synthesize the molybdenum carbonyl complex Mo(CO)4[P(OPh)3]2, which can exist in the cis- and trans-forms (Figure 1). We will use group theory and IR spectroscopy to determine which isomer is isolated. Figure 1. The cis- and trans-isomers of Mo(CO)4[P(OPh)3]2.


 Inorganic Chemistry

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Electron Paramagnetic Resonance (EPR) Spectroscopy

JoVE 10463

Source: David C. Powers, Tamara M. Powers, Texas A&M

In this video, we will learn the basic principles behind Electron Paramagnetic Resonance (EPR). We will use EPR spectroscopy to study how dibutylhydroxy toluene (BHT) behaves as an antioxidant in the autoxidation of aliphatic aldehydes.


 Inorganic Chemistry

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Schlenk Lines Transfer of Solvents

JoVE 5679

Source: Hsin-Chun Chiu and Tyler J. Morin, laboratory of Dr. Ian Tonks—University of Minnesota Twin Cities

Schlenk lines and high vacuum lines are both used to exclude moisture and oxygen from reactions by running reactions under a slight overpressure of inert gas (usually N2 or Ar) or under vacuum. Vacuum transfer has been developed as a method separate solvents (other volatile reagents) from drying agents (or other nonvolatile agents) and dispense them to reaction or storage vessels while maintaining an air-free environment. Similar to thermal distillations, vacuum transfer separates solvents by vaporizing and condensing them in another receiving vessel; however, vacuum transfers utilize the low pressure in the manifolds of Schlenk and high vacuum lines to lower boiling points to room temperature or below, allowing for cryogenic distillations. This technique can provide a safer alternative to thermal distillation for the collection of air- and moisture-free solvents. After the vacuum transfer, the water content of the collected solvent can be tested quantitatively by Karl Fischer titration, qualitatively by titration with a Na/Ph2CO solution, or by 1H NMR spectroscopy.


 Organic Chemistry

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The Evans Method

JoVE 10304

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

While most organic molecules are diamagnetic, wherein all their electrons are paired up in bonds, many transition metal complexes are paramagnetic, which has ground states with unpaired electrons. Recall Hund's rule, which states that for orbitals of similar energies, electrons will fill the orbitals to maximize the number of unpaired electrons before pairing up. Transition metals have partially populated d-orbitals whose energies are perturbed to varying extents by coordination of ligands to the metal. Thus, the d-orbitals are similar in energy to one another, but are not all degenerate. This allows for complexes to be diamagnetic, with all electrons paired up, or paramagnetic, with unpaired electrons. Knowing the number of unpaired electrons in a metal complex can provide clues into the oxidation-state and geometry of the metal complex, as well as into the ligand field (crystal field) strength of the ligands. These properties greatly impact the spectroscopy and reactivity of transition metal complexes, and so are important to understand. One way to count the number of unpaired electrons is to measure the magnetic susceptibility, χ, of the coordinatio


 Inorganic Chemistry

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Culturing and Enumerating Bacteria from Soil Samples

JoVE 10099

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Authors: Bradley Schmitz and Luisa Ikner

Surface soils are a heterogeneous mixture of inorganic and organic particles that combine together to form secondary aggregates. Within and between the aggregates are voids or pores that visually contain both air and water. These conditions create an ideal ecosystem for bacteria, so all soils contain vast populations of bacteria, usually over 1 million per gram of soil. Bacteria are the simplest of microorganisms, known as prokaryotes. Within this prokaryotic group, there are the filamentous microbes known as actinomycetes. Actinomycetes are actually bacteria, but they are frequently considered to be a unique group within the classification of bacteria because of their filamentous structure, which consists of multiple cells strung together to form hyphae. This experiment uses glycerol case media that select for actinomycete colonies, during dilution and plating. Typically, actinomycetes are approximately 10% of the total bacterial population. Bacteria and actinomycetes are found in every environment on Earth, but the abundance and diversity of these microbes in soil is unparalleled. These microbes are also essential for human life and affect what people eat


 Environmental Microbiology

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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

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Safe Handling of Mineral Acids

JoVE 10370

Source: Robert M. Rioux & Taslima A. Zaman, Pennsylvania State University, University Park, PA

A mineral acid (or inorganic acid) is defined as a water-soluble acid derived from inorganic minerals by chemical reaction as opposed to organic acids (e.g. acetic acid, formic acid). Examples of mineral acids include: • Boric acid (CAS No.10043-35-3) • Chromic acid (CAS No.1333-82-0) • Hydrochloric acid (CAS No.7647-01-0) • Hydrofluoric acid (CAS No. 7664-39-3) • Nitric acid (CAS No. 7697-37-2) • Perchloric acid (CAS No. 7601-90-3) • Phosphoric acid (CAS No.7664-38-2) • Sulfuric acid (CAS No.7664-93-9) Mineral acids are commonly found in research laboratories and their corrosive nature makes them a significant safety risk. Since they are important reagents in the research laboratory and often do not have substitutes, it is important that they are handled properly and with care. Some acids are even shock sensitive and under certain conditions may cause explosions (i.e., salts of perchloric acid).


 Lab Safety

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Photochemical Initiation Of Radical Polymerization Reactions

JoVE 10461

Source: David C. Powers, Tamara M. Powers, Texas A&M

In this video, we will carry out the photochemically initiated polymerization of styrene to generate polystyrene, which is an important commodity plastic. We will learn the fundamentals of photochemistry and use simple photochemistry to initiate radical polymerization reactions. Specifically, in this module we will examine the photochemistry of benzoyl peroxide and its role as a photo-initiator of styrene polymerization reactions. In the described experiments, we will investigate the role of wavelength, photon absorption, and excited state structure on the efficiency (measured as quantum yield) of photochemical reactions.


 Inorganic Chemistry

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