All articles starting with L
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Low-activation steel
Low-activation steel, usually called reduced-activation ferritic/martensitic (RAFM) steel, is a chromium martensitic steel for fusion reactors whose alloys, replacing molybdenum with tungsten, decay to hands-on activity within roughly a century.
Low-alcohol beer
Low-alcohol beer is beer with reduced ethanol, made by limiting fermentation (arrested fermentation, special yeasts) or by dealcoholization (vacuum distillation, membranes). Labels: ≤0.5% ABV alcohol-free in Germany/Brazil; 0.5–1.2% low-alcohol in the UK.
Low-background steel
Low-background steel, also called pre-war or pre-nuclear steel, is steel made before atmospheric nuclear testing began in the 1940s, so it is free of fallout contamination and used to shield highly sensitive radiation detectors.
Low-budget film
Low-budget film: a feature made cheaply relative to industry norms, from UK £1m definitions and Hollywood's $10m ceiling to microbudget tiers; small crews, deferred pay, private financing, and rare breakouts like The Blair Witch Project.
Low-carbohydrate diet
Low-carbohydrate diet: eating pattern under 130 g carbohydrate/day (ketogenic under 20–50 g), used for weight loss and type 2 diabetes; modest short-term advantages over low-fat diets, debated long-term cardiovascular safety.
Low-carbon cement
Low-carbon cement is cement that replaces much of Portland clinker, the most carbon-intensive component, with materials like calcined clay and limestone, cutting CO2 emissions by 30–40%.
Low-carbon concrete
Low-carbon concrete is concrete designed to cut greenhouse-gas emissions, chiefly by replacing Portland cement clinker with supplementary cementitious materials like fly ash, slag, or calcined clay.
Low-cost carrier
A low-cost carrier, also called a budget or discount airline, offers lower fares by cutting included services and charging for extras, pioneered by Southwest Airlines in the 1970s.
Low-cost Uncrewed Combat Attack System
The Low-cost Uncrewed Combat Attack System is a US Air Force effort to build cheap, jet-powered, expendable attack drones, the ancestor of its Collaborative Combat Aircraft program.
Low-coverage whole genome sequencing
Low-coverage whole genome sequencing (lcWGS) reads each genome at a small fraction of normal depth and recovers genotypes by imputation, offering cheap genome-wide genotyping across large cohorts.
Low-definition television
Low-definition television (LDTV) is a television format with resolution lower than standard-definition television, roughly MPEG-1 quality, used for mobile broadcasts such as Japan's 1-seg service.
Low-density lipoprotein
Low-density lipoprotein (LDL), "bad" cholesterol, is the most cholesterol-rich blood lipoprotein, carries one apoB-100 per particle, is cleared via the LDL receptor discovered by Brown and Goldstein (1985 Nobel), and drives atherosclerosis.
Low-density lipoprotein receptor
LDLR (low-density lipoprotein receptor), the LDL receptor gene on chromosome 19p13.2; encodes the cell-surface receptor that clears LDL cholesterol via receptor-mediated endocytosis, is regulated by SREBP-2 and degraded by PCSK9, and causes familial hypercholesterolemia when mutated.
Low-density lipoprotein receptor-related
Low-density lipoprotein receptor-related proteins (LRPs, LRP1-LRP8, megalin, VLDLR, ApoER2, LRP4): LDLR-derived transmembrane endocytic and signaling receptors involved in lipid metabolism, Wnt, Reelin, and development.
Low-density parity-check code
A low-density parity-check (LDPC) code is an error-correcting code defined by a sparse parity-check matrix, proposed by Robert G. Gallager at MIT in 1960 and used in 5G, Wi-Fi, and satellite broadcasting.
Low-density polyethylene
Low-density polyethylene, or PE-LD, is a branched, flexible form of polyethylene made from ethylene at high pressure, the first polyethylene produced commercially, in 1939, used mainly in film packaging.
Low-dose chest computed tomography
Low-dose chest computed tomography (LDCT) is a chest CT technique using about 1.5 mSv instead of 8 mSv, used chiefly for lung cancer screening in high-risk smokers.
Low-dose CT lung cancer screening
Low-dose CT lung cancer screening is an annual low-radiation chest scan for high-risk smokers, recommended in the US for adults aged 50 to 80 with at least 20 pack-years.
Low-dose electron microscopy
Low-dose electron microscopy is a set of TEM and STEM practices that minimize electron dose so beam-sensitive specimens can be imaged before radiation damage destroys their structure.
Low-dose naltrexone
Low-dose naltrexone (LDN) is the off-label use of the opioid antagonist naltrexone at roughly 0.5 to 4.5 mg daily, investigated mainly for chronic pain, inflammation, and long COVID.
Low-dose rate brachytherapy
Low-dose rate (LDR) brachytherapy is a radiation therapy technique delivering continuous low doses over weeks to months, most commonly permanent seed implantation for localized prostate cancer.
Low-dose scanning transmission electron microscopy
Low-dose scanning transmission electron microscopy (low-dose STEM) is a set of electron microscopy methods that minimize electron dose, enabling atomic-resolution imaging of beam-sensitive materials such as zeolites and metal-organic frameworks.
Low-dose whole-body computed tomography
Low-dose whole-body computed tomography is a CT technique that images the entire body at reduced radiation dose, used to assess bone disease in multiple myeloma and stage cancer.
Low-dropout regulator
A low-dropout regulator (LDO) is a linear voltage regulator that maintains its output voltage even when the input is only slightly higher than the output.
Low-emissivity coating
A low-emissivity (low-E) coating is a microscopically thin transparent coating on glass or plastic that reflects infrared heat while transmitting visible light, reducing heat transfer through windows.
Low-emissivity glass
Low-emissivity glass, or low-e glass, is window glass carrying a microscopically thin, virtually invisible metal coating that reflects infrared heat while transmitting visible light, reducing heat transfer through windows.
Low-energy electron diffraction
Low-energy electron diffraction (LEED) is a surface science technique that fires 30–300 eV electrons at a crystal surface; the diffraction pattern reveals the surface's atomic structure, first observed by Davisson and Germer in 1925.
Low-energy electron microscopy
Low-energy electron microscopy (LEEM) images surfaces with electrons of 0–100 eV landing energy, following film growth and surface dynamics in real time with nanometer resolution.
Low-energy ion scattering
Low-energy ion scattering (LEIS), also called ion scattering spectroscopy, is a surface analysis technique that determines the elemental composition of a solid's outermost atomic layer using noble gas ions.
Low-energy transfer
A low-energy transfer (LET) is a spacecraft trajectory between two bodies, such as Earth and the Moon, that uses a third body's gravity to save propellant.