Health

How eating eggs can boost heart health

Researchers have shown how moderate egg consumption can increase the amount of heart-healthy metabolites in the blood, publishing their results today in eLife.

Diseases, Conditions, Syndromes

Biomarker discovery measures COVID-19 heart disease risk

Researchers at Murdoch University's Australian National Phenome Centre have discovered a new set of biomarkers for increased risk of cardiovascular disease in patients with COVID-19 infections.

Oncology & Cancer

Receptor structure reveals new targets for cancer treatment

A molecule known as anaplastic lymphoma kinase (ALK) is a driver of several cancers, including pediatric neuroblastoma, B-cell lymphomas, and myofibroblast tumors. But for years much about this molecule—its role in the ...

Neuroscience

Findings reveal new mechanism of activation for ALK

ALK is a receptor tyrosine kinase that regulates important functions in the central nervous system. Scientists at St. Jude Children's Research Hospital have used leading-edge structural biology techniques to reveal in more ...

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Nuclear magnetic resonance

Nuclear magnetic resonance (NMR) is a property that magnetic nuclei have in a magnetic field and applied electromagnetic (EM) pulse, which cause the nuclei to absorb energy from the EM pulse and radiate this energy back out. The energy radiated back out is at a specific resonance frequency which depends on the strength of the magnetic field and other factors. This allows the observation of specific quantum mechanical magnetic properties of an atomic nucleus. Many scientific techniques exploit NMR phenomena to study molecular physics, crystals and non-crystalline materials through NMR spectroscopy. NMR is also routinely used in advanced medical imaging techniques, such as in magnetic resonance imaging (MRI).

All nuclei that contain odd numbers of nucleons have an intrinsic magnetic moment and angular momentum, in other words a spin > 0. The most commonly studied nuclei are 1H (the most NMR-sensitive isotope after the radioactive 3H) and 13C, although nuclei from isotopes of many other elements (e.g. 2H, 10B, 11B, 14N, 15N, 17O, 19F, 23Na, 29Si, 31P, 35Cl, 113Cd, 195Pt) are studied by high-field NMR spectroscopy as well.

A key feature of NMR is that the resonance frequency of a particular substance is directly proportional to the strength of the applied magnetic field. It is this feature that is exploited in imaging techniques; if a sample is placed in a non-uniform magnetic field then the resonance frequencies of the sample's nuclei depend on where in the field they are located. Since the resolution of the imaging techniques depends on how big the gradient of the field is, many efforts are made to develop more powerful magnets, often using superconductors. The effectiveness of NMR can also be improved using hyperpolarization, and/or using two-dimensional, three-dimensional and higher dimension multi-frequency techniques.

The principle of NMR usually involves two sequential steps:

The two fields are usually chosen to be perpendicular to each other as this maximises the NMR signal strength. The resulting response by the total magnetization (M) of the nuclear spins is the phenomenon that is exploited in NMR spectroscopy and magnetic resonance imaging. Both use intense applied magnetic fields (H0) in order to achieve dispersion and very high stability to deliver spectral resolution, the details of which are described by chemical shifts, the Zeeman effect, and Knight shifts (in metals).

NMR phenomena are also utilized in low-field NMR, NMR spectroscopy and MRI in the Earth's magnetic field (referred to as Earth's field NMR), and in several types of magnetometers.

This text uses material from Wikipedia, licensed under CC BY-SA