Persius/hicric huggingface dataset:
Pascal (unit)
The pascal (symbol: Pa) is the SI derived unit of pressure or stress (also: Young's modulus and tensile strength). It is a measure of perpendicular force per unit area i.e. equivalent to one newton per square meter or one joule per cubic meter. In everyday life, the pascal is perhaps best known from meteorological air-pressure reports, where it occurs in the form of kilopascal
(1 kPa = 1000 Pa). In other contexts, the kilopascal is more commonly used, for example on bicycle tire labels. One hectopascal corresponds to about 0.1% and one kilopascal to about 1% of atmospheric pressure (near sea level): one hectopascal is thus equivalent to a millibar.

# Definition

## Origin
The unit is named after Blaise Pascal, the eminent French mathematician, physicist, and philosopher noted for his experiments with a barometer, an instrument to measure air pressure.
The name pascal was adopted for the SI unit newton per square metre by the 14th CGPM in 1971. 

# Miscellaneous
Standard atmospheric pressure is 101,325 Pa = 101.325 kPa = 1013.25 hPa = 1013.25 mbar = 760 Torr. This definition is used for pneumatic fluid power (ISO R554), and in the aerospace (ISO 2533) and petroleum (ISO 5024) industries.
In 1985, IUPAC recommended that standard atmospheric pressure should be harmonized to 100,000 Pa = 1 bar = 750 Torr. The same definition is used in the compressor and the pneumatic tool industries (ISO 2787).
The Unicode computer character set has dedicated symbols Template:Unicode (Template:U+) for Pa and Template:Unicode (Template:U+) for kPa, but these exist merely for backward-compatibility with some older ideographic character-sets and are therefore deprecated.

# Uses
Meteorologists worldwide have for a long time measured atmospheric pressure in millibars. After the introduction of SI units, many preferred to preserve the customary pressure figures. Therefore, meteorologists use hectopascals (hPa) today for air pressure, which are equivalent to millibars, while similar pressures are given in kilopascals in practically all other fields, where the hecto prefix is hardly ever used. Since official metrication,  meteorologists in Canada use kilopascals (kPa), see for example CTV News, weather; current conditions in Montreal and CBC weather, current conditions in Montreal, although in some other countries hectopascals are still in use, see for example KNMI, KMI, DWD, JMA, MDD and NOAA.
In the former mts system, the unit of pressure is the pieze (symbol pz), which is equal to one kilopascal.
In the former cgs system, the unit of pressure is the barye (symbol ba), which is equal to one decipascal.
Vehicle owners' guides now specify tire inflation in kilopascals.
Ketone bodies

# Overview
Ketone bodies are three water soluble compounds that are produced as by-products when fatty acids are broken down for energy. They are used as a source of energy in the heart and brain. In the brain, they are a vital source in fasting.
The three ketone bodies are acetoacetate, beta-hydroxybutyrate and acetone, although beta-hydroxybutyrate is not technically a ketone but a carboxylic acid.

# Uses in the heart and brain
Ketone bodies can also be used for energy. Ketone bodies are transported from the liver to other tissues, where acetoacetate and beta-hydroxybutyrate can be reconverted to acetyl-CoA to produce energy, via the Krebs cycle.
The heart gets much of its energy from ketone bodies, although it also uses a lot of fatty acids.
The brain gets its energy from ketone bodies when insufficient glucose is available (e.g. when fasting). In the event of low blood glucose, most other tissues have additional energy sources besides ketone bodies (such as fatty acids) but the brain does not. After the diet has been changed to lower blood glucose for 3 days, the brain gets 30% of its energy from ketone bodies. After 4 days, this goes up to 70% (during the initial stages the brain does not burn ketones, since they are an important substrate for lipid synthesis in the brain). The brain retains some need for glucose, because ketone bodies can be broken down for energy only in the mitochondria, and brain cells' long thin axons are too far from mitochondria.

# Production
Ketone bodies are produced from acetyl-CoA (see ketogenesis) mainly in the mitochondrial matrix of liver cells when carbohydrates are so scarce that energy must be obtained from breaking down fatty acids.
Acetone is formed from spontaneous decarboxylation of acetoacetate. In a corresponding manner, the levels of acetone are much lower than those of the other two types of ketone bodies. And, unlike the other two, acetone cannot be converted back to acetyl-CoA, so it is excreted in the urine and exhaled (it can be exhaled because it has a high vapor pressure and thus evaporates easily).  The exhalation of acetone is responsible for the characteristic "fruity" odour of the breath of persons in ketotic states.

# Ketosis and ketoacidosis
Any production of these compounds is called ketogenesis, and this is necessary in small amounts.
But, when excess ketone bodies accumulate, this abnormal (but not necessarily harmful) state is called ketosis. Ketosis can be quantify by sampling the patient's exhaled air, and testing for acetone by gas chromatography.
When even larger amounts of ketone bodies accumulate such that the body's pH is lowered to dangerously acidic levels, this state is called ketoacidosis.

# Impact upon pH
Both acetoacetate and beta-hydroxybutyrate are acidic, and, if levels of these ketone bodies are too high, the pH of the blood drops, resulting in ketoacidosis.
This happens in untreated Type I diabetes (see diabetic ketoacidosis), and also in alcoholics after binge drinking and subsequent starvation (see alcoholic ketoacidosis).
Kinetoplastid
The kinetoplastids are a group of flagellate protozoa, including a number of parasites responsible for serious diseases in humans and other animals, as well as various forms found in soil and aquatic environments.  They are included in the Euglenozoa, and are distinguished from other such forms mainly by the presence of a kinetoplast, a DNA-containing granule located within the single mitochondrion and associated with the flagellar bases.
Most forms have a leading and trailing flagellum, the latter of which may or may not be attached to the side of the cell and is often used to glide along or attach to surfaces.  The cytostome is often bordered by a ridge or rostrum.  Bodo is a typical genus, including various common free-living species which feed on bacteria.  Others include Cryptobia and Trypanoplasma.  There is also one family of kinetoplastids, the trypanosomes, which only have a single emergent flagellum, including several genera which are exclusively parasitic.
Trypanosomes have reduced or absent cytostomes, feeding entirely through absorption, and smaller kinetoplasts than other forms.  They typically have complex life-cycles involving more than one host, and go through various morphological stages.  The most distinctive of these is  the trypanosome stage, where the flagellum runs along the length of the cell and is connected to it by an undulating membrane.  Diseases caused by trypanosomes include sleeping sickness and Chagas disease, from species of Trypanosoma, and leishmaniasis, from species of Leishmania.
The kinetoplastids were first defined by Honigberg in 1961 as the flagellate order Kinetoplastida.  They are traditionally divided into the biflagellate Bodonidae and uniflagellate Trypanosomatidae, which may be promoted to orders; the former appears to be paraphyletic to the latter.
Lacrimal bone

# Overview
The lacrimal bone, the smallest and most fragile bone of the face, is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders.

# Surfaces

## Lateral or orbital surface
The lateral or orbital surface is divided by a vertical ridge, the posterior lacrimal crest, into two parts.
In front of this crest is a longitudinal groove, the lacrimal sulcus (sulcus lacrimalis), the inner margin of which unites with the frontal process of the maxilla, and the lacrimal fossa is thus completed. The upper part of this fossa lodges the lacrimal sac, the lower part, the nasolacrimal duct.
The portion behind the crest is smooth, and forms part of the medial wall of the orbit.
The crest, with a part of the orbital surface immediately behind it, gives origin to the lacrimal part of the Orbicularis oculi and ends below in a small, hook-like projection, the lacrimal hamulus, which articulates with the lacrimal tubercle of the maxilla, and completes the upper orifice of the nasolacrimal canal; the hamulus sometimes exists as a separate piece, and is then called the lesser lacrimal bone.

## Medial or nasal surface
The medial or nasal surface presents a longitudinal furrow, corresponding to the crest on the lateral surface.
The area in front of this furrow forms part of the middle meatus of the nose; that behind it articulates with the ethmoid, and completes some of the anterior ethmoidal cells.

# Borders
Of the four borders:
- the anterior articulates with the frontal process of the maxilla;
- the posterior with the lamina papyracea of the ethmoid;
- the superior with the frontal bone.
- The inferior is divided by the lower edge of the posterior lacrimal crest into two parts:
the posterior part articulates with the orbital plate of the maxilla;
the anterior is prolonged downward as the descending process, which articulates with the lacrimal process of the inferior nasal concha, and assists in forming the canal for the nasolacrimal duct.
- the posterior part articulates with the orbital plate of the maxilla;
- the anterior is prolonged downward as the descending process, which articulates with the lacrimal process of the inferior nasal concha, and assists in forming the canal for the nasolacrimal duct.

# Ossification
The lacrimal is ossified from a single center, which appears about the twelfth week in the membrane covering the cartilaginous nasal capsule.

# Articulations
The lacrimal articulates with four bones: two of the cranium, the frontal and ethmoid, and two of the face, the maxilla and the inferior nasal concha.

# Additional images
- Left lacrimal bone. Orbital surface. Enlarged
- Side view of the skull.
- The skull from the front.
- Medial wall of left orbit.
- Roof, floor, and lateral wall of left nasal cavity.
Lactobacillus

# Overview
Lactobacillus is a genus of Gram-positive facultative anaerobic bacteria. They are a major part of the lactic acid bacteria group, named as such because most of its members convert lactose and other sugars to lactic acid. They are common and usually benign.  In humans they are present in the vagina and the gastrointestinal tract, where they are symbiotic and make up a small portion of the gut flora. Many species are prominent in decaying plant material. The production of lactic acid makes its environment acidic which inhibits the growth of some harmful bacteria. Several members of the genus have had their genome sequenced.

# Food production
Some Lactobacillus species are used industrially for the production of yogurt, cheese, sauerkraut, pickles, beer, wine, cider, kimchi and other fermented foods, as well as animal feeds, such as silage.  Sourdough bread is made using a "starter culture" which is a symbiotic culture of yeast and lactic acid bacteria growing in a water and flour medium. Lactobacilli, especially L. casei and L. brevis, are some of the most common beer spoilage organisms.
The species operate by lowering the pH of the fermenting substance by creating the lactic acid, neutralising it to the desired extent.

# Dental cavities
Although considered beneficial, some Lactobacillus species have been associated with dental caries.  Lactobacillus count in saliva has been used as a "caries test" for many years.  This is one of the arguments used in support of the use of fluoride in toothpaste and lozenges. 

# Metabolism
Many lactobacilli are unusual in that they operate using homofermentative metabolism (that is, they produce only lactic acid from sugars) and are aerotolerant despite the complete absence of a respiratory chain.  This aerotolerance is manganese-dependent and has been explored (and explained) in Lactobacillus plantarum. Many lactobacilli do not require iron for growth and have an extremely high hydrogen peroxide tolerance.
According to metabolism, Lactobacillus species can be divided into three groups:
- Obligately homofermentative (Group I)
L. acidophilus, L. delbrueckii, L. helveticus, L. salivarius
- L. acidophilus, L. delbrueckii, L. helveticus, L. salivarius
- Facultatively heterofermentative (Group II)
L. casei, L. curvatus, L. plantarum, L. sakei
- L. casei, L. curvatus, L. plantarum, L. sakei
- Obligately heterofermentative (Group III)
L. brevis, L. buchneri, L. fermentum, L. reuteri
- L. brevis, L. buchneri, L. fermentum, L. reuteri

# Treatment

## Antimicrobial regimen
- 1. Endovascular Infection 
- Preferred regiemn (1): Penicillin G 20 MU/day for 6 weeks
- Preferred regiemn (2): Gentamicin 1.3 mg/kg IV q8h (trough <1.5 mg/L) AND Polychlorinated naphthalene
- 2. Odontogenic Infection
- Preferred regiemn: Clindamycin 450 mg PO qid
- 3. Intrabdominal Abscess
- Preferred regiemn: Clindamycin 450 mg PO qid
Landing pages
Please access the Landing page templates from the Help Menu under "How to Create a Page" or click here.

# When to Use Landing Pages
When a disease entity is very large or has many sub-types with varying features, the author may find it useful to split the information into various microchapters, or single pages which are linked by a landing page containing general information about the disease in general. Each of the off-shooting pages from the main landing page would contain details of that specific subtype.

# How to Use a Landing Page
All pages linked to the landing page must have hyperlinks just below the headers to allow readers to access the relevant related pages, as follows:
Naturally, there will be some degree of repetition between the pages. Common segments of information may be reused across the pages along with their associated citations. Please refer to the examples below for a precedent on a "microchapter-style" landing page linking to "microchapter-style" offshoot pages, "single page-style" landing page linking to "single page-style" offshoot pages, and a "single page-style" landing page linking to a mix of microchaptered and single pages.

# Examples of Chapters Using Landing Pages
Example 1: Colitis
- Colitis is a large disease entity that has varying pathophysiological etiologies (e.g., Allergic colitis, Infectious colitis, Ulcerative Colitis, etc.). Each of the subtypes has a different epidemiology, risk factors, prognosis, history and symptoms, diagnostic features, and treatments. This chapter is a perfect candidate for a Colitis landing page with offshoot chapters for each subtype. In this case, the author has identified 8 subtypes of colitis. Three of the subtypes are in a single page format and Five are in a microchaptered format. All pages are linked to eachother and to the main page using the landing page headers.
Example 2: Pneumonia
- Pneumonia has two subtypes that each have different risk factors, underlying causes and treatments: Community Acquired Pneumonia and Hospital Acquired Pneumonia. The literature discusses these two entities separately due to a variance in the pathogen, microbial resistance, and treatment regimens. To accurately portray this information, the author created a general Pneumonia landing page and two offshoot microchaptered style pages for Community Acquired Pneumonia and Hospital Acquired Pneumonia.
Example 3: Endophthalmitis
- Endophthalmitis is another chapter that has many different classifications. Although they do not differ dramatically from one another, the large number of subtypes makes it difficult to put information about each and every type under one page without overwhelming the reader with a lot of information. Wikidoc aims to deliver high quality information to the reader in easy-to-read digestible portions.
Laplace's law

# Overview
Laplace's law or The law of Laplace may refer to several concepts,
- Biot-Savart law, in electromagnetics, it describes the magnetic field set up by a steady current density.
- Young-Laplace equation, describing pressure difference over an interface in fluid mechanics.
Latrophilin 3
Latrophilin 3 is a protein that in humans is encoded by the ADGRL3 gene.

# Function
This gene encodes a member of the latrophilin subfamily of G protein-coupled receptors (GPCR). Latrophilins may function in both cell adhesion and signal transduction. In experiments with non-human species, endogenous proteolytic cleavage within a cysteine-rich GPS (G-protein-coupled-receptor proteolysis site) domain resulted in two subunits (a large extracellular N-terminal cell adhesion subunit and a subunit with substantial similarity to the secretin/calcitonin family of GPCRs) being non-covalently bound at the cell membrane.

# Clinical significance
A version of this gene has been linked to Attention Deficit/Hyperactivity Disorder (ADHD).
Leaving group

# Overview
A leaving group is an atom or group of atoms that detaches from a chemical substance. The remaining molecule or fragment remaining is known as the residual or main part. The term leaving group is dependent on the context of the statement.
The ability for a functional group to leave is called lability. Leaving groups affect the intrinsic reactivity, not the nucleophilic discrimination factors.
The lower the pKa of the conjugate acid, the better the leaving group. This is because the lower the pKa of the conjugate acid of the leaving group, the more it stays in its anion (l.g.'s may be neutral), leaving group, form. This anion stability means that the leaving group is less likely to react with the cation formed by the leaving group's absence (this is the case with bad leaving groups). Without stabilization, a leaving group will become a nucleophile due to its negative charge, and if this happens, the reaction goes in circles.  This is why a strong base is a poor leaving group. SN1 reactions prefer halides, pseudohalides, and non-coordinating ions as leaving groups. Halide salts are particularly useful leaving groups because they can be abstracted by silver ions, to form insoluble silver halides.
In room temperature water, the sequence of lability is:
- Less lability
- amine NH2
- methoxy CH3O
- hydroxyl HO
- carboxylate CH3COO
- F
- water
- Cl
- Br
- I
- azide N3
- thiocyanate SCN
- nitro NO2
- Greater Lability
NO3 is also weaker than F.
A direct application of the difference in leaving group stability is in the carboxylic acid derivatives.  The worse the leaving group, the more stable the chemical, which makes these form a hierarchy that can be separated in the lab.  Amines, which are the worst leaving group, are the most stable compound, and attacking any carboxylic acid derivative with an amine produces an amide.  Esters are the second most stable followed by anhydrides and finally halides.
During the SN2 nucleophilic attack, a partial negative charge forms on the leaving group. During SN1 reactions, the leaving group anionizes and leaves.
In general, amine, methoxy and hydroxyl groups never act as leaving groups in a substitution reaction.
In the non-mechanistic transformations, leaving group is the actual substituent group present in the substrate and product.
The structure of the leaving group affects the rates of both Sn1 and Sn2 reactions. In general, the more stable the leaving group is as a free species--that is after it has left--the faster it will leave. This stability also reflects the basicity of the species: the more stable it is, the weaker base it is.
Leghemoglobin
The oxygen carrier leghemoglobin (also legoglobin) is a hemoprotein found in the nitrogen-fixing root nodules of leguminous plants. It is produced by legumes in response to the roots being infected by nitrogen-fixing bacteria, so-called rhizobia, as part of the symbiotic interaction between plant and bacterium: roots uninfected with Rhizobium do not synthesise leghemoglobin. Leghemoglobin has close chemical and structural similarities to hemoglobin, and, like hemoglobin, is red in colour. The protein was believed to be a product of both plant and the bacterium Template:Harv in which the apoprotein is produced by the plant and the heme (an iron atom bound in a porphyrin ring) is produced by the bacterium. Newer findings however, indicate that the heme moiety is also produced by the plant Template:Harv.
Leghemoglobin has a high affinity for oxygen (a Km of about 0.01 M), about ten times higher than the  chain of human hemoglobin.
In plants infected with Rhizobium, (such as alfalfa or soybeans), the presence of oxygen in the root nodules would reduce the activity of the oxygen-sensitive nitrogenase - an enzyme responsible for the fixation of atmospheric nitrogen. Leghemoglobin buffers the concentration of free oxygen in the cytoplasm of infected plant cells to ensure the proper function of root nodules.
Although leghemoglobin was once thought to provide a buffer for nodule oxygen, recent studies indicate that it stores only enough oxygen to support nodule respiration for a few seconds (Denison and Harter 1995). Its function is to help transport oxygen to the respiring symbiotic bacterial cells in a manner analogous to hemoglobin transporting oxygen to respiring tissues in animals (Ludwig and de Vries 1986).
Lemon battery
A lemon battery is a device used in an experiment proposed in many science textbooks around the world.
It consists of inserting two different metallic objects, for example a galvanized nail and a copper coin, into a lemon. These two objects work as electrodes, causing an electrochemical reaction which generates a small potential difference.
The aim of this experiment is to show students how batteries work. After the battery is assembled, a multimeter can be used to check the generated voltage. In order for a more visible effect to be produced, a few lemon cells connected in series can be used to power a standard LED. Flashlight bulbs are generally not used because the lemon battery cannot produce the amount of current required to light such bulbs.
The energy used to power the circuit ultimately comes from the energy used in the electrode factories to reduce metallic ions forming the solid metallic electrodes. The lemon simply provides a salt bridge for the reaction to occur. In a lemon battery, both oxidation and reduction occur. Consider the case of a zinc-copper battery. At the anode, zinc is oxidised:
At the cathode, hydrogen is reduced:
Potatoes, apples, or any other fruit or vegetable containing acid or other electrolyte can be used, but lemons are preferred because of their higher acidity. Other metal combinations (such as magnesium-copper) are more efficient: for example, using a magnesium strip instead of zinc increases the voltage from 1.1 V with zinc to 1.6 V with magnesium (the exact voltage varies depending on the lemons.) However, zinc and copper are usually preferred because they are reasonably safe and easy to obtain.

# Video Demonstrations
- Lemon Battery
- Orange Battery
- Potato Battery
Lemon verbena
Lemon verbena or Lemon beebrush (syn. Aloysia triphylla) is a deciduous perennial shrub native to Argentina, Paraguay, Brazil, Uruguay, Chile, and Peru. This plant was brought to Europe by the Spanish in the 17th century. It grows to a height of 1 to 3 metres and exudes a powerful lemony scent. It prefers full sun, a lot of water, and a light loam soil, and is sensitive to cold. The light green leaves are lancet-shaped, and its tiny flowers bloom lavender or white in August or September.
Lemon verbena leaves are used to add a lemony flavour to fish and poultry dishes, vegetable marinades, salad dressings, jams, puddings, and beverages. It also is used to make herbal teas and can make a refreshing sorbet. In addition, it has anti-Candida albicans activity.
The major isolates in lemon verbena oil are citral (30-35%), nerol and geraniol. 
Lemon verbena is also classified as Verbena triphylla L'Her., Verbena citriodora Cav., Lippia triphylla, Lippia citriodora, and Aloysia citriodora (Cav.) Ort.