Researchers have developed a mathematical model that can predict the optimum exercise regimen for building muscle.
Cell & Microbiology
Aug 23, 2021
3
2220
A number of existing strains of SARS-CoV-2, as well as other future variants that could arise, have the potential to escape the immune system's cytotoxic T cell response in some portion of the population. That's the conclusion ...
Molecular & Computational biology
Feb 10, 2022
0
797
Though they are discrete particles, water molecules flow collectively as liquids, producing streams, waves, whirlpools, and other classic fluid phenomena.
General Physics
Jul 6, 2022
1
2087
An international team of space researchers working with NASA's Goddard Space Flight Center has found previously unknown organic molecules on Mars using a new experiment aboard the Curiosity rover. The results are published ...
The search for extraterrestrial life has just become more interesting as a team of scientists, including Southwest Research Institute's Dr. Christopher Glein, has discovered new evidence for a key building block for life ...
Astrobiology
Sep 19, 2022
2
822
University of California, Irvine-led researchers have discovered that a signaling molecule called SCUBE3 potently stimulates hair growth and may offer a therapeutic treatment for androgenetic alopecia, a common form of hair ...
Cell & Microbiology
Jun 30, 2022
0
1253
Prof. Ehud Pines is an iconoclast. What else can you call a scientist who spent 17 years doggedly pursuing the solution to an over 200-year-old chemistry problem which he felt never received a satisfying answer using methods ...
Analytical Chemistry
Sep 29, 2022
0
2696
For decades, researchers around the world have searched for ways to use solar power to generate the key reaction for producing hydrogen as a clean energy source—splitting water molecules to form hydrogen and oxygen. However, ...
Materials Science
Jul 19, 2021
16
2006
Asteroid Ryugu has a rich complement of organic molecules, according to a NASA and international team's initial analysis of a sample from the asteroid's surface delivered to Earth by Japan's Hayabusa2 spacecraft. The discovery ...
Planetary Sciences
Feb 23, 2023
1
633
A team of researchers led by Meenesh Singh at University of Illinois Chicago has discovered a way to convert 100% of carbon dioxide captured from industrial exhaust into ethylene, a key building block for plastic products.
Materials Science
Sep 9, 2022
33
1275
A molecule is defined as a sufficiently stable, electrically neutral group of at least two atoms in a definite arrangement held together by very strong (covalent) chemical bonds. Molecules are distinguished from polyatomic ions in this strict sense. In organic chemistry and biochemistry, the term molecule is used less strictly and also is applied to charged organic molecules and biomolecules.
In the kinetic theory of gases the term molecule is often used for any gaseous particle regardless of its composition. According to this definition noble gas atoms are considered molecules despite the fact that they are composed of a single non-bonded atom.
A molecule may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O). Atoms and complexes connected by non-covalent bonds such as hydrogen bonds or ionic bonds are generally not considered single molecules.
No typical molecule can be defined for ionic crystals (salts) and covalent crystals (network solids), although these are often composed of repeating unit cells that extend either in a plane (such as in graphene) or three-dimensionally (such as in diamond or sodium chloride). The theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding. In glasses (solids that exist in a vitreous disordered state), atoms may also be held together by chemical bonds without any definable molecule, but also without any of the regularity of repeating units that characterises crystals.
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