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Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
 JoVE Environment

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

1Department of Animal Science, Pennsylvania State University, 2C-Lock, Inc. Rapid City, SD, 3Color Productions, State College, PA, 4Departamento de Zootecnia, Universidade Estadual de Maringá

JoVE 52904

 JoVE Bioengineering

The Portable Chemical Sterilizer (PCS), D-FENS, and D-FEND ALL: Novel Chlorine Dioxide Decontamination Technologies for the Military

1United States Army-Natick Soldier RD&E Center, Warfighter Directorate, 2Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 3Lawrence Livermore National Laboratory, 4Children's Hospital Oakland Research Institute

JoVE 4354

 Science Education: Essentials of Environmental Science

Carbon and Nitrogen Analysis of Environmental Samples

JoVE Science Education

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

Elemental Analysis is a method used to determine elemental composition of a material. In environmental samples such as soils, scientists are particularly interested in the amounts of two ecologically important elements, nitrogen and carbon. Elemental analysis by the flash combustion technique works by oxidizing the sample with a catalyst through combustion in a high-temperature chamber. The products of combustion are then reduced to N2 and CO2 and detected with a thermal conductivity detector. Unlike other methods for total nitrogen determination (Kjeldahl method) and total carbon determination (Walkley-Black, Heanes or Leco methods), the flash combustion technique does not use toxic chemicals and is therefore much safer to use. This video will demonstrate combustion-based elemental analysis using the Flash EA 1112 instrument from Thermo Fisher Scientific.

 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 General Chemistry

Ideal Gas Law

JoVE Science Education

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 variables (pressure, temperature, and volume) and the number of molecules of gas in the system, and is therefore an essential link between the microscopic and the macroscopic universes. The history of the ideal gas law dates to the middle of the 17th century when the relationship between the pressure and volume of air was found to be inversely proportional, an expression confirmed by Robert Boyle and which we now refer to as Boyle’s law (Equation 1). P V-1 (Equation 1) Unpublished work by Jacques Charles in the 1780s, which was extended to numerous gases and vapors by Joseph Louis Gay-Lussac and reported in 1802, established the directly proportional relationship between the absolute temperature and volume of a gas. This relationship is called Charles's law (Equ

 Science Education: Essentials of Organic Chemistry

Conducting Reactions Below Room Temperature

JoVE Science Education

Source: Laboratory of Dr. Dana Lashley - College of William and Mary

Demonstration by: Matt Smith

When new bonds are formed in the course of a chemical reaction, it requires that the involved species (atoms or molecules) come in very close proximity and collide into one another. The collisions between these species are more frequent and effective the higher the speed at which these molecules are moving. A widely used rule of thumb, which has its roots in the Arrhenius equation1, states that raising the temperature by 10 K will approximately double the rate of a reaction, and raising the temperature by 20 K will quadruple the rate: (1) Equation (1) is often found in its logarithmic form: (2) where k is the rate of the chemical reaction, A is the frequency factor (relating to frequency of molecular collisions), Ea is the activation energy required for the reaction, R is the ideal gas constant, and T is the temperature at which the r

 Science Education: Essentials of Physical Examinations I

Respiratory Exam I: Inspection and Palpation

JoVE Science Education

Source: Suneel Dhand, MD, Attending Physician, Internal Medicine, Beth Israel Deaconess Medical Center

Disorders of the respiratory system with a chief complaint of shortness of breath are among the most common reasons for both outpatient and inpatient evaluation. The most obvious visible clue to a respiratory problem will be whether the patient is displaying any signs of respiratory distress, such as fast respiratory rate and/or cyanosis. In a clinical situation, this will always require emergent attention and oxygen therapy. Unlike pathology in other body systems, many pulmonary disorders, including chronic obstructive pulmonary disease (COPD), asthma, and pneumonia, can be diagnosed by careful clinical examination alone. This starts with a comprehensive inspection and palpation. Keep in mind that in non-emergency situations the patient's complete history will have been taken already, gaining important insight into exposure histories (e.g., smoking), which could give rise to specific lung diseases. This history can then confirm physical findings as the examination is performed.

 JoVE Biology

Whole-Body Nanoparticle Aerosol Inhalation Exposures

1Department of Physiology and Pharmacology, School of Medicine, West Virginia University, 2Center for Cardiovascular and Respiratory Sciences, West Virginia University, 3National Institute for Occupational Safety and Health

JoVE 50263

 Science Education: Essentials of Environmental Science

Biofuels: Producing Ethanol from Cellulosic Material

JoVE Science Education

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

In this experiment, cellulosic material (such as corn stalks, leaves, grasses, etc.) will be used as a feedstock for the production of ethanol. The cellulosic material is first pretreated (ground and heated), digested with enzymes, and then fermented with yeast. Ethanol production is monitored using an ethanol probe. The experiment can be extended to optimize ethanol production by varying the feedstock used, pretreatment conditions, enzyme variation, yeast variation, etc. An alternative method of monitoring the reaction is to measure the carbon dioxide produced (using a gas sensor) instead of the ethanol. As a low-tech alternative, glucose meters (found in any drug store) can be used to monitor the glucose during the process, if an ethanol probe or carbon dioxide gas sensor is not available. With an increased emphasis on ‘inquiry-based learning”, scientific probes are becoming more popular. Handheld devices like the Vernier Lab Quest used in conjunction with a variety of probes (such as those for conductivity, dissolved oxygen, voltage, and more) allow for less focus on collecting data and/or making graphs and more on analyzing the data and making predictions. Anothe

 JoVE Environment

Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

1Office of Sustainability, University of Wisconsin-Madison, 2Department of Soil Science, University of Wisconsin-Madison, 3Department of Agronomy, University of Wisconsin-Madison, 4Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, 5USDA-ARS Dairy Forage Research Center, 6USDA-ARS Pasture Systems Watershed Management Research Unit

JoVE 52110

 Science Education: Essentials of Environmental Microbiology

Algae Enumeration via Culturable Methodology

JoVE Science Education

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

Algae are a highly heterogeneous group of microorganisms that have one common trait, namely the possession of photosynthetic pigments. In the environment, algae can cause problems for swimming pool owners by growing in the water. Algae can also cause problems in surface waters, such as lakes and reservoirs, due to algal blooms that release toxins. More recently, algae are being evaluated as novel sources of energy via algal biofuels. Blue-green algae are actually bacteria classified as cyanobacteria. Cyanobacteria not only photosynthesize, but also have the ability to fix nitrogen gas from the atmosphere. Other algae are eukaryotic, ranging from single-celled organisms to complex multicellular organisms, like seaweeds. These include the green algae, the euglenoids, the dinoflagellates, the golden brown algae, diatoms, the brown algae, and the red algae. In soils, algal populations are frequently 106 per gram. These numbers are lower than corresponding numbers for bacteria, actinomycetes, and fungi, mostly because the sunlight required for photosynthesis cannot penetrate far beneath the soil surface. Because algae are phototrophic, obtaining energy from photosyn

 JoVE Bioengineering

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

1Department of Obstetrics, Perinatal Pharmacology, University Hospital Zurich, 2Laboratory for Materials - Biology Interactions, EMPA Swiss Federal Laboratories for Materials Testing and Research, 3Graduate School for Cellular and Biomedical Sciences, University of Bern

JoVE 50401

 JoVE Neuroscience

Non-restraining EEG Radiotelemetry: Epidural and Deep Intracerebral Stereotaxic EEG Electrode Placement

1Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), 2Molecular and Cellular Cognition Lab, German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE)

JoVE 54216

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