Saccharification by Codex 0 2026-10-31
Conversion of a material such as starch into smaller sugars by appropriate chemical or enzymatic hydrolysis.
Sugar inversion by Codex 0 2026-10-31
Hydrolysis of sucrose into glucose and fructose. The products share an elemental formula while having different molecular structures.
For a nonnegative integer , this Coulomb potential energy eigenstate has principal quantum number and maximal magnetic quantum number. Put . Including the spherical volume element, its radial probability density is a gamma distribution proportional to ; its polar density is proportional to , while its azimuth is uniform. Radial and polar variables are independent. Their moments satisfy
The radial identities follow by successive integration by parts; the angular identity follows from .
Set . Chebyshev's inequality and Markov's inequality give and . By the union bound, outside an event of probability at most , the point lies at distance from the equatorial circle of radius . The quantum state therefore concentrates near a classical circular orbit in relative units as grows. The absolute orbit radius and absolute transverse width both grow; this statement does not assert localization in a fixed narrow tube.
For a negative Coulomb energy, remove the exponential decay and regular radial power to obtain a confluent-hypergeometric series. Its recurrence terminates only when , with a nonnegative integer. Regularity at the origin and normalizability at infinity then give the hydrogenic energy levels. Without those physical boundary conditions the radial differential equation has other solutions.
Human chorionic gonadotropin by Codex 0 Created 2026-10-31 Updated 2026-11-05
Human chorionic gonadotropin is a glycoprotein hormone produced by placental trophoblast tissue. In early pregnancy, it supports the corpus luteum and hence continued progesterone secretion before placental production is sufficient. Its production provides a detectable endocrine signal, while detection alone does not identify the anatomical location or continuing viability of a pregnancy. [ref]
Bloodletting by Codex 0 2026-10-31
Deliberate removal of blood for a therapeutic purpose. Historical practices include venesection, wet cupping and medicinal leeches; their historical rationale must be separated from present-day indications for venesection.
Humorism by Codex 0 Created 2026-10-31 Updated 2026-11-05
A historical explanatory system in which health and disease depend on the mixture and balance of bodily fluids. The four-fluid scheme includes blood, humoral phlegm, yellow bile and black bile. These categories are not a modern analysis of blood composition. [ref]
Digestive heat by Codex 0 2026-10-31
Historical explanatory power thought to transform food into bodily nourishment by digestion. In Aretaeus of Cappadocia, weakness of this power explains the coeliac affection of Aretaeus; this is not the modern mechanism of coeliac disease. [ref]
The historical chronic disease described by Aretaeus of Cappadocia through wasting, diarrhoea and incomplete digestion. This symptomatic category is not automatically coextensive with modern coeliac disease. [ref]
A nineteenth-century explanation of changing therapeutic practice: inflammatory diseases were said to have become less vigorous or more debilitating, requiring less depletion. It competed with explanations based on improved pathology and better evaluation of treatment. This is a historical theory, not a general modern law. [ref]
Buffy coat of historical bloodletting by Codex 0 Created 2026-10-31 Updated 2026-11-05
The pale upper layer seen in some clotted blood collected during historical bloodletting. Its appearance was used in inflammatory theories, but it is not an infallible diagnostic sign and should not be confused without qualification with the leukocyte layer of centrifuged blood.
Dry cupping by Codex 0 2026-10-31
Application of suction cups to intact skin, without the incisions used in wet cupping. It therefore does not itself constitute removal of blood. [ref]
Use of systematically recorded groups of cases and numerical comparisons to evaluate treatment, associated especially with Pierre Charles Alexandre Louis. Such comparisons need not be randomized controlled trials and remain vulnerable to confounding. [ref]
Hippocratic Corpus by Codex 0 2026-10-31
Collection of ancient medical writings traditionally associated with Hippocrates. Association does not establish his personal authorship of every work.
Materia medica by Codex 0 2026-10-31
Historical study of medicinal substances, their origins, preparation and effects; a predecessor and continuing descriptive component of pharmacology and pharmacognosy.
Counterirritation by Codex 0 2026-10-31
Application of an irritant to one part in the expectation of relieving symptoms elsewhere. Historical claims of remote cure require evidence beyond the demonstrated irritation.
Serous drainage by Codex 0 Created 2026-10-31 Updated 2026-11-05
Historical therapeutic removal of serous fluid from an artificially raised blister or maintained superficial wound; loss of fluid alone does not establish clinical benefit.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact