Mass Accumulation

In manufacturing, production costs are accumulated and tracked to understand how resources are consumed and how they contribute to the final product. This process, known as cost accumulation, involves recording material, labor, and overhead costs and linking them to specific cost objects, such as individual products or production processes.Costs flow through inventory accounts in a sequence that mirrors the physical movement of goods. Initially, raw materials are recorded in the raw materials...

This video demonstrates an assay to measure the accumulation of a fluorescent antibiotic probe in bacterial cells. Exposure to an efflux pump inhibitor disrupts the transmembrane proton gradient in bacterial cells, upon which a fluorophore-conjugated antibiotic is added. Inhibition of efflux pumps due to the disrupted proton gradient causes accumulation of the antibiotic inside the bacteria. Bacterial cells are lysed, and the fluorescence intensity is measured to confirm antibiotic accumulation.

Lipid droplets are important organelles for the replication of several pathogens, including the Hepatitis C Virus (HCV). We describe a method to isolate lipid droplets for quantitative mass spectrometry of associated proteins; it can be used under a variety of conditions, such as virus infection, environmental stress, or drug treatment.

The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, water, H2O, and hydrogen peroxide, H2O2, are alike in that their respective molecules are composed of hydrogen and oxygen atoms. However, because a hydrogen peroxide molecule contains two oxygen atoms, as opposed to the water molecule, which has only one, the two substances exhibit very different properties. Atoms and molecules are extremely...

Atoms — and the protons, neutrons, and electrons that compose them — are extremely small. For example, a carbon atom weighs less than 2 × 10−23 g. When describing the properties of tiny objects such as atoms, we use appropriately small units of measure, such as the atomic mass unit (amu). The amu was originally defined based on hydrogen, the lightest element, then later in terms of oxygen. Since 1961, it has been defined with regard to the most abundant isotope of carbon, atoms of which are...