News tagged with atoms
New findings by researchers carrying out experiments at the U.S. Department of Energy Office of Science's Advanced Photon Source (APS) help explain why some drugs that interact with two kinds of human serotonin ...
Medical research May 17, 2013 | 4 / 5 (1) | 0 |
Scientists provide detailed view of brain protein structure: Results may help improve drugs for neurological disorders
Researchers have published the first highly detailed description of how neurotensin, a neuropeptide hormone which modulates nerve cell activity in the brain, interacts with its receptor. Their results suggest that neuropeptide ...
Medical research Oct 10, 2012 | 5 / 5 (1) | 0 |
A team including scientists from The Scripps Research Institute (TSRI), the University of North Carolina at Chapel Hill and the Chinese Academy of Sciences has determined and analyzed the high-resolution ...
Medical research Mar 21, 2013 | 4.8 / 5 (5) | 0 |
Researchers at UC Davis and the University of British Columbia have shed new light on methylation, a critical process that helps control how genes are expressed. Working with placentas, the team discovered that 37 percent ...
Genetics Mar 27, 2013 | 5 / 5 (3) | 0 |
More than 70 years after the first sulfa drugs helped to revolutionize medical care and save millions of lives, St. Jude Children's Research Hospital scientists have determined at an atomic level the mechanism these medications ...
Medical research Mar 01, 2012 | 5 / 5 (3) | 0 |
(Medical Xpress)—New Georgia Tech research shows that cell stiffness could be a valuable clue for doctors as they search for and treat cancerous cells before they're able to spread. The findings, which ...
Cancer Oct 10, 2012 | not rated yet | 0 |
Measuring enzyme levels in cancer patients may reveal healthy cells' ability to survive chemotherapy
New research from MIT may allow scientists to develop a test that can predict the severity of side effects of some common chemotherapy agents in individual patients, allowing doctors to tailor treatments ...
Genetics Apr 05, 2013 | not rated yet | 0 |
An atomic-level snapshot of a respiratory syncytial virus (RSV) protein bound to a human antibody represents a leap toward developing a vaccine for a common—and sometimes very serious—childhood disease. ...
Diseases, Conditions, Syndromes Apr 25, 2013 | not rated yet | 0 |
Scientists this month reported the molecular structural basis for severe head deformities and ambiguous sex organs in babies born with Antley-Bixler syndrome accompanied by an enzyme deficiency.
Medical research Aug 19, 2011 | 5 / 5 (1) | 0 |
HIV is coated in sugars that usually hide the virus from the immune system. Newly published research reveals how one broadly neutralizing HIV antibody actually uses part of the sugary cloak to help bind to the virus. The ...
HIV & AIDS Nov 23, 2011 | 5 / 5 (2) | 0 |
Scientists at The Scripps Research Institute have determined the atomic structure of a protein that the Lassa fever virus uses to make copies of itself within infected cells. The structural data reveal an ...
Medical research Nov 15, 2011 | 5 / 5 (3) | 0 |
A researcher at The Feinstein Institute for Medical Research has discovered additional mechanical properties of articular cartilage, a protective cartilage on the ends of bones that wears down over time, resulting in the ...
Arthritis & Rheumatism Apr 19, 2013 | not rated yet | 0
A new technique based on atomic force microscopy was developed at the Institute of Food Research to help 'read' information encoded in the gut lining.
Medical research Apr 12, 2013 | 4 / 5 (1) | 0
The complement system is part of the innate immune system and is composed of about 40 different proteins that work together to defend the body against disease-causing microorganisms. The complement system ...
Immunology Sep 11, 2012 | not rated yet | 0
(Medical Xpress)—New research from the University of Reading could be crucial in the fight to stop the spread of killer viruses such as HIV and avian flu.
Medical research Mar 04, 2013 | not rated yet | 0
The atom is a basic unit of matter consisting of a dense, central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutron). The electrons of an atom are bound to the nucleus by the electromagnetic force. Likewise, a group of atoms can remain bound to each other, forming a molecule. An atom containing an equal number of protons and electrons is electrically neutral, otherwise it has a positive or negative charge and is an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determine the isotope of the element.
The name atom comes from the Greek ἄτομος/átomos, α-τεμνω, which means uncuttable, something that cannot be divided further. The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 17th and 18th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods. During the late 19th and early 20th centuries, physicists discovered subatomic components and structure inside the atom, thereby demonstrating that the 'atom' was divisible. The principles of quantum mechanics were used to successfully model the atom.
Relative to everyday experience, atoms are minuscule objects with proportionately tiny masses. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope. Over 99.9% of an atom's mass is concentrated in the nucleus, with protons and neutrons having roughly equal mass. Each element has at least one isotope with unstable nuclei that can undergo radioactive decay. This can result in a transmutation that changes the number of protons or neutrons in a nucleus. Electrons that are bound to atoms possess a set of stable energy levels, or orbitals, and can undergo transitions between them by absorbing or emitting photons that match the energy differences between the levels. The electrons determine the chemical properties of an element, and strongly influence an atom's magnetic properties.
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