Persius/hicric huggingface dataset:
Suture (joint)
- Surgery, to describe stitches and other techniques for holding tissues together.
A suture is a type of fibrous joint which only occurs in the the skull (or "cranium"). They are bound together by Sharpey's fibres. A tiny amount of movement is permitted at sutures, which contributes to the compliance and elasticity of the skull.
These joints are synarthroses.
It is normal for many of the bones of the skull to remain unfused at birth. The term "fontanelle" is used to describe the resulting "soft spots". The relative positions of the bones continue to change during the life of the adult (though less rapidly), which can provide useful information in forensics and archaeology. In old age, cranial sutures may ossify (turn to bone) completely.

# List of sutures
Most sutures are named for the bones they articulate, but some have special names of their own.

## Primarily visible from the side (norma lateralis)
- Coronal suture - between the frontal and parietal bones
- Lambdoid suture - between the parietal bones and the occipital boneis it the osteror sinus
- Occipitomastoid suture
- Parietomastoid suture
- Sphenofrontal suture
- Sphenoparietal suture
- Sphenosquamosal suture
- Sphenozygomatic suture
- Squamosal suture - between the parietal and the temporal bone
- Zygomaticotemporal suture
- Zygomaticofrontal suture

## Primarily visible from front (norma frontalis) or above (norma verticalis)
- Frontal suture / Metopic suture - between the two frontal bones, prior to the fusion of the two into a single bone
- Sagittal suture - along the midline, between parietal bones

## Primarily visible from below (norma basalis) or inside
- Frontoethmoidal suture
- Petrosquamous suture
- Sphenoethmoidal suture
- Sphenopetrosal suture
Slater's rules
Slater's Rules are  a set of rules devised by  John C. Slater that give an approximate estimate of effective nuclear charge on an electron (Z*).
Z*=Z-S
where S is the screening constant.
The system involves the two following steps:
1.Arrange sets according to principle quantum number, ignoring filling order and keeping ns and np together
i.e       
2.Using the table, calculate the contributions to S (the screening constant) for electrons in each set.
Slosh dynamics
Slosh refers to the movement of liquid inside another object that is under motion. The liquid must have a free surface for it to be a slosh dynamics problem. The dynamics of the liquid can interact with the object that contains to alter its dynamics significantly.

# Practical Effects
It is an important effect for aircraft and spacecraft.  Slosh was a factor in the recent Falcon 1 2nd test flight problem.
The effect of slosh is used to limit the bounce of a roller hockey ball. Water slosh can significantly reduce the rebound height of a ball but some amounts of liquid seem to lead to a resonance effect.   Many of the balls for roller hockey commonly avaialble contain water to reduce the bounce height.
Snow blindness

# Overview
Snow blindness is a painful condition, typically a keratitis, caused by exposure of unprotected eyes to the ultraviolet (UV) rays in bright sunlight reflected from snow or ice. This is especially a problem in polar regions and at high altitudes, as with every thousand feet increase in elevation, the intensity of UV rays goes up five percent.
The problem is also related to the condition arc eye sometimes experienced by welders.
Snow blindness is akin to a sunburn of the cornea and conjunctiva, and may not be noticed for several hours from exposure. Symptoms can run the gamut from eyes being bloodshot and teary to increased pain, feeling gritty and swelling shut. In very severe cases, snow blindness can cause permanent vision loss.
The Inuit carved goggles from caribou antler to help prevent snow blindness. The goggles were curved to fit the user's face and had a large groove cut in the back to allow for the nose. A long thin slit was cut through the goggles to allow in a small amount of light. The goggles were held to the head by a cord made of caribou sinew.

# Prevention
When trekking, mountaineering or skiing, sunglasses that offer the following are frequently recommended:
- 99-100% UV absorption
- Polycarbonate or CR-39 lens
- 5-10% visible light transmittance
- Large lenses that fit close to the face and cover the whole eye
- Wraparound, side-shielded, or dark-lensed 'glacier' glasses to prevent incidental light exposure
- Wear even when the sky is overcast, as UV rays can still filter through clouds
- In the event of lost or damaged sunglasses, make emergency goggles by cutting slits in dark fabric or tape folded back onto itself

# Treatment
Following these guidelines will allow the pain and symptoms of snow blindness to disappear as the cornea heals:
- Avoid rubbing eyes and remove contact lenses
- Administer an oral pain medication such as ibuprofen
- Cover eyes with soft thick cloth pads or gauze bandages to prevent irritation from eyelid movement and protect from light; rest in a dark room if possible
- Apply cold wet compresses to ease burning sensations
- Check injury at half-day intervals; remove dressing when eyes can remain open comfortably
- Wear sunglasses outside until symptoms completely disappear
Sodium cyanide
Sodium cyanide is a highly toxic chemical compound, also known as sodium salt of hydrocyanic acid and cyanogran.  Immediate medical attention is required in the event of cyanide poisoning, as it is quickly fatal. Like the similar potassium cyanide, NaCN has a smell like bitter almonds, but not everyone can smell it due to a genetic trait.
Sodium cyanide is used to extract gold and other precious metals from ore, and so metal mining operations consume most of the sodium cyanide production; see cyanide process for the use in gold mining. Sodium cyanide is illegally used to collect fish; see cyanide fishing. Accidents with cyanide solutions are a severe danger to aquatic ecosystems. It is often used by entomologists as a killing agent in collecting jars, as most insects succumb within seconds, minimizing damage of even the most fragile types.

# Toxicity
Cyanide salts are among the most rapidly acting of all known poisons.  Cyanide is a potent inhibitor of respiration, acting on mitochondrial cytochrome oxidase and hence blocking electron transport. This results in decreased oxidative metabolism and oxygen utilization. Lactic acidosis then occurs as a consequence of anaerobic metabolism.  Initially, acute cyanide poisoning causes a red or ruddy complexion in the victim because the tissues are not able to use the oxygen in the blood.
The effects of sodium cyanide are similar to potassium cyanide. Once more than 100200 mg of sodium cyanide is consumed, consciousness is lost within one minute, sometimes within 10 seconds, depending on the strength of the body's immunity and the amount of food present in the stomach. After a span of about 45 minutes, the body goes into a state of coma or deep sleep and the person may die within two hours if not treated medically. During this period, convulsions may occur. Death occurs mainly by cardiac arrest.

# Source
- Institut national de recherche et de securite (1997). "Cyanure de sodium. Cyanure de potassium". Fiche toxicologique n 111, Paris:INRS, 6pp. (PDF file, in French)
Sodium nitrate
Sodium nitrate is the chemical compound with the formula NaNO3.  This salt, also known as saltpeter, is a white solid which is very soluble in water. Sodium nitrate is used as an ingredient in fertilizers, explosives, and in solid rocket propellants, as well as in glass and pottery enamels; the compound has been mined extensively for those purposes.
The mining of so-called "Chile saltpeter" was such a profitable business that three nations, Chile, Peru, and Bolivia fought over the richest deposits in the War of the Pacific. The world's largest natural deposits of caliche ore were in the Atacama desert of Chile, and many deposits were mined for over a century, until the 1940s, when its value declined dramatically in the first decades of the twentieth century (see Haber Process). The former Chilean saltpeter mining communities of Humberstone and Santa Laura were declared Unesco World Heritage sites in 2005.
Chile still has the largest reserves of caliche, with active mines in such locations as Pedro de Valdivia, Maria Elena and Pampa Blanca. Sodium nitrate, potassium nitrate, sodium sulfate and iodine are all obtained by the processing of caliche.
Sodium nitrate is also synthesized industrially by neutralizing nitric acid with soda ash.

# Applications
Sodium nitrate was used extensively as a fertilizer and a raw material for the manufacture of gunpowder in the late nineteenth century.
Sodium nitrate has antimicrobial properties when used as a food preservative. It is found naturally in leafy green vegetables.
Sodium nitrate should not be confused with the related compound, sodium nitrite. The presence of sodium nitrite in food is controversial due to the development of nitrosamines when the food, primarily bacon, is cooked at high temperatures. The nitrate compound itself is not harmful, however, and is among the antioxidants found in fresh vegetables.  Its usage is carefully regulated in the production of cured products; in the United States, the concentration in finished products is limited to 200 ppm, and is usually lower.
It can be used in the production of nitric acid by combining it with sulfuric acid and subsequent separation through fractional distillation of the nitric acid, leaving behind a residue of sodium bisulfate.
Less common applications include its use as a substitute oxidizer used in fireworks as a replacement for potassium nitrate commonly found in black powder.
Because sodium nitrate can be used as a Phase Change Material it may be used for heat transfer in solar power plants.

# Notes and references
-  National Academy of Sciences - National Research Council Academy of Life Sciences. "The Health Effects of Nitrate, Nitrite and N-Nitroso Compounds". Washington DC: National Academy Press, 1981
-  www.freepatentsonline.com/6877508.html
Solanum nigrum
Solanum nigrum (Black Nightshade, Duscle, Garden Nightshade, Hound's Berry, Petty Morel, Small-fruited black nightshade, Sunberry, or Wonderberry) is a species in the Solanum genus, native to Eurasia and also introduced in the Americas. In Hawaii it is called popolo.
The green berries and mature leaves contain glycoalkaloids and are poisonous to eat raw. Their toxicity varies and there are some strains which have edible berries when fully ripe. The plant has a long history of medicinal usage, dating back to ancient Greece.
Black nightshade is a fairly common plant, found in many wooded areas, as well as disturbed habitats. It has a height of 30-120 cm (12-48"), leaves 4-7.5 cm (1 1/2-3") long; ovate to heart-shaped, with wavy or large-toothed edges. The flowers have petals greenish to whitish, recurved when aged and surround prominent bright yellow anthers. The fruits are oval black berries in small hanging clusters.
Spatial memory
In cognitive psychology and neuroscience, spatial memory is the part of memory responsible for recording information about one's environment and its spatial orientation. For example, a person's spatial memory is required in order to navigate around a familiar city, just as a rat's spatial memory is needed to learn the location of food at the end of a maze.  It is often argued that a person's, or an animal's, spatial memories are summarised in a cognitive map.
Spatial memories are formed after an organism gathers and processes sensory information about its surroundings (especially vision and proprioception). In general, mammals require a functioning hippocampus (particularly area CA1) in order to form and process memories about space. There is some evidence that human spatial memory is strongly tied to the right hemisphere of the brain   .
Spatial learning requires both NMDA and AMPA receptors, consolidation requires NMDA receptors, and the retrieval of spatial memories requires AMPA receptors .
The study of spatial memory provides valuable information about the type of complex processes which occurs in humans. It gives insight, into complex procedures.  For example, species such as the grey squirrel or Clark's Nutcracker, which are scatter hoarders (making numerous small caches, usually of nuts) show a remarkable ability to return to their caches months later.  Such species often have a larger hippocampus, relative to overall brain size, than related non-hoarding species.  Spatial memory is also important in animal migration, and in foraging in complex environments with many different food sources which become available in different seasons, the situation that faces many frugivorous primates.

# Important Cortical Regions
- Prefrontal cortex
- Retrosplenial cortex
- Posterior parietal cortex
- Perirhinal cortex
- Entorhinal cortex
- Hippocampus
Spermatic cord

# Overview
The spermatic cord is the name given to the cord-like structure in males formed by the vas deferens and surrounding tissue that run from the abdomen down to each testicle.

# Contents of spermatic cord
- arteries: testicular artery, deferential artery, cremasteric artery
- nerves: nerve to cremaster (genital branch of the genitofemoral nerve) , sympathetic nerves
- vas deferens
- pampiniform plexus
- lymphatic vessels
- processus vaginalis (remains of)

# Coverings
The spermatic cord is ensheathed in three layers of tissue:
- external spermatic fascia, an extension of the innominate fascia that overlies the aponeurosis of the external oblique muscle
- cremasteric muscle and fascia, formed from a continuation of the internal oblique muscle and its fascia
- internal spermatic fascia, continuous with the transversalis fascia

# Clinical significance
The spermatic cord is sensitive to torsion, in which the testicle rotates within its sac and kinks off its own blood supply. Testicular torsion may result in irreversible damage to the testicle within hours.
The contents of the abdominal cavity may protrude into the spermatic cord, producing an indirect inguinal hernia.

# Additional images
- The left femoral triangle.
- The scrotum.
- The right testis, exposed by laying open the tunica vaginalis.
Spermatogonium
A spermatogonium (plural: spermatogonia) is an intermediary male gametogonium (a kind of germ cell) in the production of spermatozoa.
There are two subtypes:
Type A(d) cells have dark nuclei and they divide to produce copies of themselves, thereby ensuring a constant supply of spermatogonia to fuel spermatogenesis.
Type A(p) cells have pale nuclei and they divide by mitosis to produce Type B cells and these Type B cells divide again to give rise to primary spermatocytes.
Each primary spermatocyte duplicates its DNA and subsequently undergoes meiosis I to produce two haploid secondary spermatocytes. Each of the two secondary spermatocytes further undergo meiosis II to produce two spermatids (haploid). (1 primary spermatocytes => 4 spermatids)
The spermatids then undergo spermiogenesis to produce spermatozoa.

# Additional images
- Transverse section of a tubule of the testis of a rat. X 250.
- Schematic diagram of Spermatocytogenesis

# Source
This article includes material from Biology Online.
de:Spermatogonium
Sphincterotomy
Sphincterotomy is a surgical procedure that involves the removal of fissures from the sphincter. The word is formed from sphincter + otomy (to cut, to separate).

# Procedure
- The surgery can be performed under any kind of anesthesia.
- After anesthesia is administered, the area is cleaned with an antiseptic solution.
- The sphincter is separated either by simply stretching or cutting. Cutting the muscle prevents spasm and temporarily weakens the muscles. Both methods help the underlying area to heal.
- Remove the fissure and any underlying scar tissue.
- Suture back the wound.
Sputum culture

# Overview
A sputum culture is a test to detect and identify bacteria or fungi that are infecting the lungs or breathing passages. Sputum is a thick fluid produced in the lungs and in the airways leading to the lungs. A sample of sputum is placed in a container with substances that promote the growth of bacteria or fungi. If no bacteria or fungi grow, the culture is negative. If organisms that can cause infection (pathogenic organisms) grow, the culture is positive. The type of bacterium or fungus will be identified with a microscope or by chemical tests.
If bacteria or fungi that can cause infection grow in the culture, other tests may be done to determine which antibiotic will be most effective in treating the infection. This is called susceptibility or sensitivity testing.
This test is done on a sample of sputum that is usually collected by coughing. For people who cannot cough deeply enough to produce a sample, a suction tube or needle may be inserted in the airway to collect the sputum.
In a hospital setting, a sputum culture is most commonly ordered if a patient has a pneumonia.  The Infectious Diseases Society of America recommends that sputum cultures be done in pneumonia requiring hospitalization, while the American College of Chest Physicians does not.  The reasons for the discrepancy is that normal, healthy lungs have bacteria, and sputum cultures collect both normal bacteria and the bacteria causing disease.  It is difficult to tell which bacteria is causing the disease in this setting.
Standard score
In statistics, the standard score, also called the z-score or normal score, is a dimensionless quantity derived by subtracting the population mean from an individual raw score and then dividing the difference by the population standard deviation.  This conversion process is called standardizing or normalizing.
The standard score indicates how many standard deviations an observation is above or below the mean. It allows comparison of observations from different normal distributions, which is done frequently in research.
The standard score is not the same as the z-factor used in the analysis of high-throughput screening data, but is sometimes confused with it.

# Formula
The quantity z represents the distance between the raw score and the population mean in units of the standard deviation.  z is negative when the raw score is below the mean, positive when above.
A key point is that calculating z requires the population mean and the population standard deviation, not the sample mean or sample deviation.  It requires knowing the population parameters, not the statistics of a sample drawn from the population of interest. But knowing the true standard deviation of a population is often unrealistic except in cases such as standardized testing, where the entire population is measured.  In cases where it is impossible to measure every member of a population, the standard deviation may be estimated using a random sample.  For example, a population of people who smoke cigarettes is not fully measured.
When a population is normally distributed, the percentile rank may be determined from the standard score and statistical tables.

# Standardizing in mathematical statistics
In mathematical statistics, a random variable X is standardized using the theoretical (population) mean and standard deviation:
where  = E(X) is the mean and  = the standard deviation of the probability distribution of X.
If the random variable under consideration is the sample mean:
then the standardized version is
Standard state
In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). This pressure was changed from 1 atm (101.325 kilopascals) by IUPAC in 1990. The standard state of a material can be defined at any given temperature, most commonly 25 degrees Celsius, although quite a few texts (especially in related disciplines such as physics and engineering) use 0 degrees Celsius for Standard Temperature and Pressure (STP).
It should be noted that the standard state is an arbitrarily chosen non-zero value, not a natural zero point.
For a given material or substance, the standard state is the reference state for the material's  thermodynamic state properties such as enthalpy, entropy, Gibbs free energy, and for many other material standards. The standard enthalpy of formation for an element in its standard state is 0.
When the standard state is referred to a solute in a solution, or to a chemical reaction, it also includes the condition that the concentrations of all solutes are at unity (or another designated quantity) for whatever measure of concentration is specified. If that is molarity that would be 1 moldm-3 and for molality 1 molkg-1 assuming  the solution infinite-dilution behaviour. If mole fraction is used, the pure liquid or solid is the standard state (x=1). As it is possible (and in principle legitimate) to take a different unit for each of the species in the reaction, the nature of the standard state needs to be specified when reporting or tabulating. Although a definition involving 1 mol/L (molarity at unity) of A in combination with pure B (mole fraction at unity) is clearly a condition that can never be met, such a non-existent standard state nevertheless leads to a consistent system of tabulated values, provided it is used consistently by all. Of course these values are different from those where a different standard state is adopted.
In chemistry of solutions at elevated temperatures and pressures, the term "standard state" often denotes the hypothetical standard concentration, typically 1 mol/kg for solutes assuming an ideal behaviour (i.e., an infinite dilution), or a unity molar fraction (for pure substances). It does not imply any particular temperature or pressure because, although contrary to IUPAC recommendation, it is more convenient when describing solutions over a wide temperature and pressure ranges.
In the time of their development (the 19th century) the Plimsoll - symbol was adopted as a superscript o to indicate the non-zero nature of the chosen reference state. For typographic reasons this symbol is often abridged to a rather misleading zero superscript 0 in later texts.
State variable
A state variable is an element of the set of variables that describe the state of a dynamical system.
In case of simple mechanical systems, position coordinates and their derivates are typical state variables. Temperature, pressure, internal energy, enthalpy, entropy are examples of state variables in a  thermodynamics system.

# Control Systems Engineering
In Control Engineering and other areas of science and engineering, state variables are used to represent the states of a general system. The state variables can be used to describe the state space (controls) of the system. The equations relating the current state and output of a system to its current input and past states are called the state equations. The state equations for a linear time invariant system are expressed with Coefficient matrices:
A\,\!  existing in dimension  RN*N
B\,\!  existing in dimension  RN*L
C\,\!  existing in dimension  RM*N
D\,\!  existing in dimension  RM*L

### Discrete-Time Systems
The state variable representing the current state of a discrete-time system (i.e. digital systems) is x(n)\,, where n is the discrete point at which the system is being evaluated. The discrete-time state equations are

### Continuous Time Systems (Analog)
The state variable representing the current state of a continuous-time system (i.e. analog systems) is x(t)\,, and the continuous time state equations are