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Hydrochloric Acid: A strong corrosive acid that is commonly used as a laboratory reagent. It is formed by dissolving hydrogen chloride in water. Gastric acid is the hydrochloric acid component of Gastric juice.

Conversion of Fatty Acid Methyl Esters by Saponification for Uk'37 Paleothermometry

JoVE 10158

Source: Laboratory of Jeff Salacup - University of Massachusetts Amherst


The product of an organic solvent extraction, a total lipid extract (TLE), is often a complex mixture of hundreds, if not thousands, of different compounds. The researcher is often only interested in a handful of compounds or, if interested in many, may need to remove unwanted constituents that…

 Earth Science

What is Monogastric Digestion?

JoVE 10829

The human body contains a monogastric digestive system. In a monogastric digestive system, the stomach only contains one chamber in which it digests food. Several other animal species also have monogastric digestive systems, including pigs, horses, dogs, and birds. This chapter, however, focuses on the human digestive system.

Saliva is a watery substance secreted by the salivary glands into the mouth. Human saliva contains 99.5% water with electrolytes, mucus, white blood cells, epithelial cells, enzymes, and antimicrobial agents. The enzymes found in saliva are essential in beginning the process of digestion. They also play a role in breaking down food particles trapped around the teeth, protecting them from decay. Saliva is obtained easily, inexpensively, and non-invasively from patients which spurs research interest. Ongoing research identified novel ways of using saliva in molecular diagnostics. DNA, RNA, and proteins found in saliva serve as useful sources of diagnostic information in the early detection of various cancers including oral, pancreatic, and gastric cancer. The primary component of gastric acid is hydrochloric acid. Hydrogen and chloride ions released by parietal cells lining the stomach react in the stomach cavity to form hydrochloric acid. Parietal cells are coupled to feedback systems that increase and decrease acid prod

 Core: Nutrition and Digestion

Diffusion and Osmosis - Student Protocol

JoVE 10564

Diffusion in Agar
NOTE: In this exercise, you will be given agar containing an indicator chemical called phenolphthalein. When phenolphthalein is exposed to the normal alkaline conditions in the agar, it will look pink. But when it is exposed to neutral or acidic conditions, it changes from pink to clear. You will make different size and shaped agar…

 Lab Bio

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…

 Lab Safety

Cell Division - Student Protocol

JoVE 10572

Observing the Cell Cycle in a Root Tip
Hypotheses: The experimental hypothesis is that in root tips slices that have been treated with nocodazole, a chemical that interferes with microtubular polymerization, all of the cells will be arrested at the same stage of the cell cycle and that in untreated onion tip slices all of the different stages of the…

 Lab Bio

Hormonal Regulation

JoVE 10836

Hormones regulate a significant portion of digestion through activation of the neuroendocrine system. The neuroendocrine system of digestion contains many different hormones all with multiple functions that are both, directly and indirectly, involved in digestion.

Starting in the stomach, when proteins are detected by sensory neurons of the enteric nervous system, the pyloric gland is stimulated to release gastrin. In turn, this hormone induces the release of histamine. Combined, they initiate the production of hydrochloric acid which facilitates digestion—turning food into chyme. When the pH of the stomach becomes more acidic, a negative feedback loop halts the production of both hormones. The chyme then moves to the duodenum, where several hormones are released—each with multiple functions. Some inhibit digestion in the stomach. Gastric inhibitory peptide (GIP) slows stomach churning. Secretin inhibits gastric juice production and, along with cholecystokinin (CCK), induces the pyloric sphincter between the stomach and duodenum to close. This limits the volume of chyme in the duodenum, pacing the rate of digestion. Once the chyme is in the duodenum, secretin prompts the release of bicarbonate from the pancreas. This reduces the acidity of the chyme, protecting the sensitive lining of the duodenum and setting up an optimal environment

 Core: Nutrition and Digestion

Physical Properties Of Minerals II: Polymineralic Analysis

JoVE 10001

Source: Laboratory of Alan Lester - University of Colorado Boulder


The physical properties of minerals include various measurable and discernible attributes, including color, streak, magnetic properties, hardness, crystal growth form, and crystal cleavage. These properties are mineral-specific, and they are fundamentally related to a particular mineral’s chemical make-up and …

 Earth Science

Determining the Solubility Rules of Ionic Compounds

JoVE 10197

Source: Laboratory of Dr. Neal Abrams — SUNY College of Environmental Science and Forestry


An ionic compound's solubility can be determined via qualitative analysis. Qualitative analysis is a branch of analytical chemistry that uses chemical properties and reactions to identify the cation or anion present in a chemical compound.…

 General Chemistry

Tensile Strength of Resorbable Biomaterials

JoVE 10471

Source: Peiman Shahbeigi-Roodposhti and Sina Shahbazmohamadi, Biomedical Engineering Department, University of Connecticut, Storrs, Connecticut


For over 4000 years, sutures have been used as a medical intervention. The earliest records indicate linen was the biomaterial of choice. Catgut, which is still in use today, was reportedly used to …

 Biomedical Engineering

Diffusion and Osmosis - Prep Student

JoVE 10563

Preparation of Solutions for the Agar Cube Experiment
IMPORTANT: Wear gloves, goggles, and appropriate personal protective equipment – chemicals can be hazardous at high concentrations.
For the diffusion indicator solution, weigh out 1 g of phenolphthalein and add it to a beaker containing 100 mL of 95% ethanol.
To make the basic…

 Lab Bio

Cleaning Glassware

JoVE 10342

Source: Vy M. Dong and Daniel Kim, Department of Chemistry, University of California, Irvine, CA


Organic synthesis is about transforming a readily available reagent into a more valuable product. Having clean glassware is crucial for the efficiency of this process. Dirty glassware can potentially affect the reaction and make isolation of…

 Organic Chemistry II

Electroplating of Thin Films

JoVE 10489

Source: Logan G. Kiefer, Andrew R. Falkowski, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT


Electroplating is a process that uses electric current to reduce dissolved metal cations so that they form a thin coating on an electrode. Other thin film deposition techniques…

 Materials Engineering

Reducing Agents

JoVE 10354

Source: Vy M. Dong and Daniel Kim, Department of Chemistry, University of California, Irvine, CA


Controlling the reactivity and selectivity during the synthesis of a molecule is very important criteria for chemists. This has led to the development of many reagents that allow chemists to pick and choose reagents suitable for a given task.…

 Organic Chemistry II

Cell Division - Prep Student

JoVE 10626

Preparation of Onion Root Tips and Solutions
For the cell cycle experiment using root tips, first, leave an onion suspended over a beaker of water to grow roots for several days.
Then, clean the onion roots of any dirt or debris.
Next, in a 1.5 mL tube, dissolve 10 mcg of nocodazole per 1 mL of dimethyl sulfoxide solution, making 1 tube…

 Lab Bio

Basic Care Procedures

JoVE 10290

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN


Mice and rats account for over 90% of the animals used for biomedical research. The proper care of these research animals is critical to the outcome of experiments. There are general procedures that apply to the majority of these mice and…

 Lab Animal Research

Introduction to Mass Spectrometry

JoVE 5634

Source: Laboratory of Dr. Khuloud Al-Jamal - King's College London



Mass spectrometry is an analytical chemistry technique that enables the identification of unknown compounds within a sample, the quantification of known materials, the determination of the structure, and chemical properties of different molecules.

 Analytical Chemistry

Soil Nutrient Analysis: Nitrogen, Phosphorus, and Potassium

JoVE 10077

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


In this experiment, three soil macronutrients are chemically extracted, combined with color-based reagents, then analyzed using color to determine the nutrient concentration present in the soil sample.


Nitrogen, phosphorus, and…

 Environmental Science

Lead Analysis of Soil Using Atomic Absorption Spectroscopy

JoVE 10021

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


Lead occurs naturally in soil, in levels ranging from 10-50 ppm. However, with the widespread use of lead in paint and gasoline in addition to contamination by industry, urban soils often have concentrations of lead significantly greater than background levels…

 Environmental Science

Sample Preparation for Analytical Characterization

JoVE 10205

Source: Laboratory of Dr. B. Jill Venton - University of Virginia


Sample preparation is the way in which a sample is treated to prepare for analysis. Careful sample preparation is critical in analytical chemistry to accurately generate either a standard or unknown sample for a chemical measurement. Errors in analytical chemistry…

 Analytical Chemistry

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…

 Chemical Engineering

Determining the Empirical Formula

JoVE 10181

Source: Laboratory of Dr. Neal Abrams - SUNY College of Environmental Science and Forestry


Determining the chemical formula of a compound is at the heart of what chemists do in the laboratory every day. Many tools are available to aid in this determination, but one of the simplest (and most accurate) is the determination of the empirical…

 General Chemistry

Making Solutions in the Laboratory

JoVE 5030

The ability to successfully make solutions is a basic laboratory skill performed in virtually all biological and chemical experiments. A solution is a homogenous mixture of solute dissolved in bulk liquid known as the solvent. Solutions can be described by their solute concentration, a measure of how much solute is present per unit of solution.

In this…

 General Laboratory Techniques

Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids

1Department of Biocatalysis, Institute of Chemistry, Technische Universität Berlin, 2Department of Bioenergetics, Institute of Chemistry, Technische Universität Berlin, 3Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Department of Molecular Genetics, University of Groningen

JoVE 57551

 Bioengineering

Construction of Models for Nondestructive Prediction of Ingredient Contents in Blueberries by Near-infrared Spectroscopy Based on HPLC Measurements

1United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 2Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3Institute of Agriculture, Tokyo University of Agriculture and Technology

JoVE 53981

 Chemistry

Detection and Genogrouping of Noroviruses from Children's Stools By Taqman One-step RT-PCR

1Laboratorio de Investigación y Desarrollo (LID), Universidad Peruana Cayetano Heredia, 2Bloomberg School of Public Health, Johns Hopkins University, 3Laboratorio de Diagnostico Molecular, Facultad de Medicina, University of Concepcion,Chile, 4University of California San Diego School of Medicine

JoVE 3232

 Medicine
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