For cancer cells to metastasize, they must first break free of a tumor's own defenses. Most tumors are sheathed in a protective "basement" membrane—a thin, pliable film that holds cancer cells in place as they grow and ...
Mar 8, 2021
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That very fine hair-line object that you see being pulled across the screen is actually a neuron being made. A research team led by McGill University and the Montreal Neurological Institute has managed to create new functional ...
Jan 28, 2016
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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 ...
Oct 10, 2012
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A new study has found a molecule hailed as a potential drug candidate for Parkinson's disease is no longer an effective therapeutic option. The WEHI-led research has debunked over 10 years of research that suggested a specific ...
Jan 22, 2024
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Most neurodegenerative diseases, including dementias, involve proteins aggregating into filaments called amyloids. In most of these diseases, researchers have identified the proteins that aggregate, allowing them to target ...
Dec 6, 2023
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An international team of researchers has developed a handheld, non-invasive device that can detect biomarkers for Alzheimer's and Parkinson's Diseases. The biosensor can also transmit the results wirelessly to a laptop or ...
Nov 13, 2023
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Neurons talk to each other using chemical signals called neurotransmitters. Scientists at St. Jude Children's Research Hospital have drawn on structural biology expertise to determine structures of vesicular monoamine transporter ...
Nov 1, 2023
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Deep inside our cells— each one complete with an identical set of genes— a molecular machine known as PRC2 plays a critical role in determining which cells become heart cells, vs. brain or muscle or skin cells.
Sep 26, 2023
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Mutations in a genetic region that regulates RNA stability could influence prostate cancer outcomes and drug resistance, according to new work from scientists at Fred Hutchinson Cancer Center published in Cell Reports.
Aug 7, 2023
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In a new paper published today in Nature, researchers at the Francis Crick Institute have outlined the structure and function of a protein complex that is required to repair damaged DNA and protect against cancer.
Jun 21, 2023
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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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