Inflammation of the larynx.

Noisy breathing associated with narrowing of the upper airway.

Equality of repeated time intervals; for an oscillator, independence of its oscillation period from amplitude in the stated regime. Ideal simple harmonic motion is isochronous. A simple pendulum has this property only approximately at small amplitude.

Conversion of suitable covalently bound nitrogen, sulfur or halogens into species detectable in an aqueous extract. Incomplete conversion and interfering species require controls.

Original textbook chapter by John McMurry, published by OpenStax. Cited opening paragraph and mechanism: sulfuric-acid-catalysed production of symmetrical ethers from primary alcohols. Used for chemical explanation, not as an 1865 official recipe.

Cited Oxidation of Monosaccharides: reducing sugars and base-catalysed fructose isomerization.

A sulfonic acid contains the group $\mathrm{R}-\mathrm{S}(=\mathrm{O}{)}_2-\mathrm{OH}$, where R is bonded to sulfur through carbon. Loss of the hydroxyl proton produces a sulfonate ion.

Many sulfonic acids are strong acids in water. Their ionic derivatives can give an otherwise hydrophobic organic framework a strongly polar headgroup, a useful combination in surfactants.

A vacuole is a membrane-bounded cellular compartment with roles that can include storage, degradation and regulation of water and ion balance. The large central vacuole of a typical plant cell is bounded by the tonoplast. Solute accumulation can favour entry of water by osmosis, contributing to turgor pressure against the cell wall. A vacuole is consequently an actively maintained compartment rather than simply an empty space. ^[ref]

Colour produced through wavelength-dependent interaction with spatial structure, such as thin-film interference or diffraction, rather than pigment absorption alone.

An optical physicist studies optics through mathematical theory, observation or experiment. The field determines the relevant physical systems and measurements, while the individual biographies below connect particular contributions with their scientific ideas.

Poisoning by opium, distinguished historically from other causes of coma.

A mismatch between the eye’s focusing power and its image plane for the specified viewing condition. Myopia, hyperopia and ocular astigmatism describe different optical patterns rather than every form of visual impairment.

Assessment of the optical correction needed to focus an image on the retina. Objective measurements and subjective comparisons provide complementary estimates of spherical and astigmatic correction.

Surgery intended to change the optical focusing properties of the eye. Altering corneal shape or another optical component changes refraction; it does not repair every cause of impaired vision.

Inflammation involving the corneal stroma. It can alter transparency without being defined as a primary surface ulcer, connecting tissue depth with effects on vision.

Inflammation of the conjunctiva. Infectious, allergic and irritant causes can produce overlapping redness, so the anatomical diagnosis alone does not identify its cause.

Online chapter: pages.cs.wisc.edu/~remzi/OSTEP/file-disks.pdf

Chapter 37 of Operating Systems: Three Easy Pieces by Remzi H. Arpaci-Dusseau and others. Section 37.3 separates seek, rotational delay and transfer time; the later scheduling discussion compares shortest-seek and directional-sweep policies. The parent record supplies the authors and version metadata.

Sections on types of cancer, including carcinoma, sarcoma, leukaemia, lymphoma and melanoma.

PDQ Health Professional Version; “Pathophysiology of N&V” describes visceral afferent pathways and coordinated efferent responses.

Introduction; Classification; Findings at Diagnosis table; Leukemoid reaction. Review February 2026.