Scientists from the National University of Singapore (NUS) Department of Pharmacy have developed an improved pharmaceutical drug for the treatment of the most common heart rhythm disturbance—atrial fibrillation (AF). The ...
Jul 18, 2022
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Ten years ago, scientists announced the end of the Human Genome Project, the international attempt to learn which combination of four nucleotides—adenine, thymine, cytosine, and guanine—is unique to homo sapien DNA. This ...
Aug 8, 2013
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Magnetic resonance imaging (MRI) has transformed the field of neuroscience over the past 40 years, enabling scientists to create clear snapshots of living brain structures and even detect functional changes associated with ...
Apr 11, 2022
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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 ...
Mar 27, 2013
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Postdoctoral Research Fellow Devin Koestler is a biostatistician in the Geisel School of Medicine at Dartmouth. He develops and applies statistical methods to large volumes of data, seeking new approaches for understanding ...
Oct 12, 2012
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In very rare cases, the needles of prefilled syringes may become blocked. This can have potentially detrimental consequences for patients if their medication does not enter the body or the dosage is too low.
Feb 29, 2024
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A new finding provides fresh hope for the millions of women worldwide with oestrogen receptor positive breast cancer. Australian scientists have shown that a specific change, which occurs when tumours become resistant to ...
Jul 22, 2013
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BOSTON—When people with a family history of colorectal cancer develop the disease, their tumors often carry a molecular sign that the cancer could be life-threatening and may require aggressive treatment, Dana-Farber Cancer ...
Dec 12, 2012
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All proteins are made from chains of amino acids and their functions can be modified by adding small molecules to specific amino acids. One such modification is the addition of a methyl group, which is made of one carbon ...
Feb 1, 2013
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Risk of heart and blood vessel disease may increase when a particular gene is switched off, according to preliminary research presented at the American Heart Association's Emerging Science Series Webinar.
Jun 19, 2013
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A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively-charged proton and a single negatively-charged electron bound to the nucleus by the Coulomb force. The most abundant isotope, hydrogen-1, protium, or light hydrogen, contains no neutrons; other isotopes contain one or more neutrons. This article primarily concerns hydrogen-1.
The hydrogen atom has special significance in quantum mechanics and quantum field theory as a simple two-body problem physical system which has yielded many simple analytical solutions in closed-form.
In 1914, Niels Bohr obtained the spectral frequencies of the hydrogen atom after making a number of simplifying assumptions. These assumptions, the cornerstones of the Bohr model, were not fully correct but did yield the correct energy answers. Bohr's results for the frequencies and underlying energy values were confirmed by the full quantum-mechanical analysis which uses the Schrödinger equation, as was shown in 1925/26. The solution to the Schrödinger equation for hydrogen is analytical. From this, the hydrogen energy levels and thus the frequencies of the hydrogen spectral lines can be calculated. The solution of the Schrödinger equation goes much further than the Bohr model however, because it also yields the shape of the electron's wave function ("orbital") for the various possible quantum-mechanical states, thus explaining the anisotropic character of atomic bonds.
The Schrödinger equation also applies to more complicated atoms and molecules. However, in most such cases the solution is not analytical and either computer calculations are necessary or simplifying assumptions must be made.
This text uses material from Wikipedia, licensed under CC BY-SA
