All articles starting with N
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Neutron moderator
A neutron moderator is a material, such as light water, heavy water, or graphite, that slows fast fission neutrons in a reactor core, making further fission more likely.
Neutron poison
A neutron poison, also called a nuclear poison, is a non-fissionable substance that absorbs neutrons in a reactor core, adding negative reactivity to control fission.
Neutron radiation
Neutron radiation is ionizing radiation consisting of free neutrons, uncharged subatomic particles from fission and fusion. Neutrons penetrate deeply, are hard to shield, and can make objects radioactive.
Neutron radiography
Neutron radiography is an imaging technique that transmits a collimated neutron beam through an object; because neutrons interact with nuclei, light elements show strongly inside metals, unlike X-ray imaging.
Neutron reflectometry
Neutron reflectometry, also known as neutron reflectivity or neutron reflection, is a scattering technique measuring neutron reflection from flat surfaces and interfaces, probing buried layers, magnetic films, and solid–liquid boundaries.
Neutron research facilities
Neutron research facilities are large scientific installations that produce intense neutron beams in nuclear reactors or spallation sources, letting researchers study materials at the atomic scale.
Neutron scattering
Neutron scattering is a family of experimental techniques that directs free neutrons at a sample to determine atomic structure and dynamics, probing light elements where X-rays fail.
Neutron skin
A neutron skin is an excess of neutrons at the outer surface of a neutron-rich atomic nucleus, quantified as the difference between neutron and proton radii.
Neutron source
A neutron source is any device or material that emits neutrons, ranging from isotopic capsules to research reactors and particle accelerators used in well logging and materials science.
Neutron spectroscopy
Neutron spectroscopy measures the energy distribution of neutrons emitted by a source, used in fusion research to determine plasma ion temperature, fuel composition, and fast-ion velocity distributions.
Neutron spin echo
Neutron spin echo is a neutron scattering technique using Larmor precession to measure molecular motions, with the highest energy resolution of all neutron spectroscopy methods.
Neutron spin echo spectroscopy
Neutron spin echo spectroscopy is a neutron scattering technique that uses the Larmor precession of neutron spins as an internal clock to detect extremely small energy transfers.
Neutron star
A neutron star is the dense core left when a massive star collapses, crushing more than the Sun's mass into a city-sized sphere about 20 kilometers wide.
Neutron Star Interior Composition Explorer
NICER, the Neutron Star Interior Composition Explorer, is a NASA X-ray telescope mounted on the International Space Station in 2017 to measure neutron star masses and radii.
Neutron star merger
A neutron star merger is the collision of two neutron stars in a compact binary, emitting gravitational waves and producing a kilonova and heavy elements.
Neutron star–black hole merger
A neutron star–black hole merger (NSBH merger) is the coalescence of a binary with one neutron star and one stellar-mass black hole, first confirmed by gravitational waves from the events GW200105 and GW200115 in 2021.
Neutron superfluidity in Cassiopeia A
Neutron superfluidity in Cassiopeia A is the 2011 explanation for the unusually rapid cooling of the neutron star at the center of the Cassiopeia A supernova remnant.
Neutron tomography
Neutron tomography is an imaging method that reconstructs an object's 3D internal structure from neutron transmission measurements, highlighting light elements like hydrogen inside thick metal parts.
Neutron transport theory
Neutron transport theory is the branch of nuclear science that describes how neutrons move through matter, centered on the Boltzmann transport equation and nuclear reactor analysis.
Neutron-capture elements
Neutron-capture elements are the elements heavier than iron, built when atomic nuclei capture free neutrons in stars or explosive events, via the s-, r-, and i-processes.
Neutron-induced fission
Neutron-induced fission is the splitting of a heavy atomic nucleus after it absorbs a neutron, discovered by Otto Hahn and Fritz Strassmann in Berlin in 1938.
Neutropaenia
Neutropaenia (neutropenia) is a low absolute neutrophil count, below 1.5 × 10⁹/L, graded mild, moderate, severe, or agranulocytosis; caused by chemotherapy, drugs, infection, autoimmune or congenital defects, and treated with G-CSF and prompt antibiotics when febrile.
Neutropenia
Neutropenia: ANC below 1500/µL, raising infection risk. Also febrile neutropenia, agranulocytosis, congenital forms such as Kostmann syndrome, and G-CSF prophylaxis after chemotherapy.
Neutrophil
Neutrophil (polymorphonuclear leukocyte, PMN): the most abundant human white blood cell, up to 70% of blood leukocytes, a short-lived innate immune cell that kills pathogens by phagocytosis, granules, ROS, and NETs, and is implicated in inflammation, thrombosis, autoimmunity, and cancer.
Neutrophil apoptotic process
Neutrophil apoptotic process (GO:0001781), also known as neutrophil apoptosis, is the programmed death of neutrophils by apoptosis, which keeps their toxic contents contained and promotes resolution of inflammation.
Neutrophil cytosol factor P40
Neutrophil cytosol factor P40 (p40phox, NCF4, Ncf4) is a 339-aa, 39 kDa cytosolic NADPH oxidase subunit whose PX domain binds PtdIns(3)P on phagosomes; NCF4 mutations cause a mild CGD subgroup.
Neutrophil degranulation
Neutrophil degranulation (GO:0043312; Reactome R-HSA-6798695) is the regulated exocytosis of neutrophil granules: azurophil, specific, gelatinase, ficolin-1-rich granules and secretory vesicles release antimicrobial proteins in a calcium-regulated sequence, driving immunity and inflammatory disease.
Neutrophil elastase
Neutrophil elastase (ELANE, EC 3.4.21.37) is a trypsin-fold serine protease stored in neutrophil azurophilic granules (~67,000 molecules each) that cleaves elastin (Val P1 preference), defends against bacteria, drives NETs, and causes emphysema, bronchiectasis damage, and ELANE-mutation neutropenias.
Neutrophil Infiltration
Neutrophil infiltration, also called neutrophil recruitment or extravasation, is the chemokine-driven migration of neutrophils from blood into inflamed tissue via selectin rolling, integrin adhesion, and transmigration; central to host defense, chronic inflammation, and cancer.
Neutrophilia
Neutrophilia (好中球増加症), ICD-11 4B00.1, is an elevated absolute neutrophil count above 7.7 × 10⁹/L in adults, caused by increased production, demargination, or decreased egress, most often reactive to infection, inflammation, drugs, or myeloid neoplasms.