Persius/hicric huggingface dataset:
Occlusal splint

# Overview
Occlusal splints (also called bite splints, bite planes, or night guards) are removable dental appliances carefully molded to fit the upper or lower arches of teeth.
They are used to protect tooth and restoration surfaces, manage mandibular (jaw) disfunction, and stabilize occlusion or create space prior to restoration procedures. People prone to nocturnal bruxism, or nighttime clenching, should routinely wear occlusal splints (sometimes called night guards in this context) at night.
Occlusal splints are typically made of a heat-cured acrylic resin. Soft acrylic or light cured composite, or vinyl splints may be made more quickly and cheaply, but are not as durable, and are more commonly made for short-term use. Soft splints are also used for children, because normal growth changes the fit of hard splints.
They generally cover all the teeth of the upper or lower arch, but partial coverage is sometimes used. Occlusal splints are usually used on either the upper or the lower teeth, termed maxillary splints or mandibular splints respectively, but sometimes both types are used at the same time. Maxillary splints are more common, although various situations favor mandibular splints.
Stabilizing or Michigan-type occlusal splints are generally flat against the opposing teeth, and help jaw muscle relaxation, while repositioning occlusal splints are used to reposition the jaw to improve occlusion.
Olfactory nerve
The olfactory nerve, or cranial nerve I, is the first of twelve cranial nerves. The specialized olfactory receptor neurons of the olfactory nerve are located in the olfactory mucosa of the upper parts of the nasal cavity. The olfactory nerve consists of a collection of sensory nerve fibers that extend from the olfactory epithelium to the olfactory bulb, passing through the many openings of the cribriform plate, a sieve-like structure.
Olfactory receptor neurons continue to be born throughout life and extend new axons to the olfactory bulb.  Olfactory ensheathing glia wrap bundles of these axons and are thought to facilitate their passage into the central nervous system.
The sense of smell (olfaction) arises from the stimulation of the olfactory receptors by activation from gas molecules that pass by the nose during respiration. The resulting electrical activity is transduced into the olfactory bulb which then transmits the electrical activity to other parts of the olfactory system and the rest of the central nervous system via the olfactory tract.
The olfactory nerve is the shortest of all the twelve cranial nerves and only one of two cranial nerves (the other being the optic nerve) that do not join with the brainstem.

# Testing the Olfactory nerve
To test the function of the olfactory nerve, doctors block one of the patient's nostrils and place a pungent odor (such as damp coffee essence) under the open nostril. The test to see if the patient can detect the smell is then repeated on the other nostril.

# Additional images
Rivea corymbosa
Rivea corymbosa (common synonym: Turbina corymbosa), is a species of morning glory plants, native throughout Latin America from Mexico in the North to Peru in the South and widely naturalised elsewhere. It is a perennial climbing vine with white flowers, often planted as an ornamental plant. This plant also occurs in Cuba, where it usually blooms from early December to February. Its flowers secrete copious amount of nectar, and the honey the bees make from it is very clear and aromatic. It is considered one of the main honey plants from the island.
Known to natives of Mexico as Ololiuqui (also spelled ololiuhqui or ololiuqui), its seeds, while little known outside of Mexico, were perhaps the most common hallucinogenic drug used by the natives.
In 1941, Richard Evans Schultes first identified ololiuhqui as Rivea corymbosa and the chemical composition was first described on August 18, 1960, in a paper by Dr. Albert Hofmann. The seeds contain ergine (LSA), an ergoline alkaloid similar in structure to LSD.
The Nahuatl word ololiuhqui means "round thing", and refers to the small, brown, oval seeds of the morning glory, not the plant itself, which is called coaxihuitl, "snake-plant", in Nahuatl, and hiedra or bejuco in the Spanish language. The seeds, in Spanish, are sometimes called semilla de la Virgen (seeds of the Virgin Mary).
The seeds are also used by Native curers in order to gain knowledge in curing practices and ritual, as well as the causes for the illness.
Vitelline veins

# Overview
The vitelline veins are veins which drain blood from the yolk sac.

# Path
They run upward at first in front, and subsequently on either side of the intestinal canal.
They unite on the ventral aspect of the canal, and beyond this are connected to one another by two anastomotic branches, one on the dorsal, and the other on the ventral aspect of the duodenal portion of the intestine, which is thus encircled by two venous rings; into the middle or dorsal anastomosis the superior mesenteric vein opens.
The portions of the veins above the upper ring become interrupted by the developing liver and broken up by it into a plexus of small capillary-like vessels termed sinusoids.

# Derivatives
The branches conveying the blood to this plexus are named the venae advehentes, and become the branches of the portal vein.
The vessels draining the plexus into the sinus venosus are termed the venae revehentes, and form the future hepatic veins. Ultimately the left vena revehens no longer communicates directly with the sinus venosus, but opens into the right vena revehens.
The persistent part of the upper venous ring, above the opening of the superior mesenteric vein, forms the trunk of the portal vein.

# Additional images
- Chick embryo of thirty-three hours incubation, viewed from the dorsal aspect. X 30.
- Model of human embryo 1.3 mm. long.
- Head of chick embryo of about thirty-eight hours incubation, viewed from the ventral surface. X 26.
- Diagram to illustrate the simple tubular condition of the heart.
- Liver with the septum transversum. Human embryo 3 mm. long.
Onychodystrophy

# Overview
Onychodystrophy is a deformation of the nails that can result from cancer chemotherapy which includes bleomycin, hydroxyurea, or 5-fluorouracil. It can include discoloration of the nail, or dyschromia.

# Causes

## Causes in Alphabetical Order
- Eczema
- Fungal infection
- Psoriasis

# Diagnosis

## Physical Examination
Image shown below is courtesy of Professor Peter Anderson DVM PhD and published with permission  PEIR, University of Alabama at Birmingham, Department of Pathology
- Hydroxyurea Nails; Nail changes associated with Hydroxyurea therapy in a patient with essential thrombocythemia
Opioid overview

# Overview
An opioid is a chemical substance that has a morphine-like action in the body. The main use is for pain relief. These agents work by binding to opioid receptors, which are found principally in the central nervous system and the gastrointestinal tract. The receptors in these two organ systems mediate both the beneficial effects, and the undesirable side effects. There are a number of broad classes of narcotics:
- natural opiates, alkaloids contained in the resin of the opium poppy including morphine, codeine, thebaine, and oripavine;
- semi-synthetic opiates, created from the natural opioids, such as hydromorphone, hydrocodone, oxycodone, and heroin;
- fully synthetic opioids, such as fentanyl, pethidine, methadone, and propoxyphene;
- endogenous opioid peptides, produced naturally in the body, such as endorphins, enkephalins, dynorphins, and endomorphins.
Although the term opiate is often used as a synonym for opioid, it is more properly limited to the natural opium alkaloids and the semi-synthetics derived from them.
Amongst analgesics are a small number of agents which act on the central nervous system but not on the opioid receptor system and therefore have none of the other (narcotic) qualities of opioids although they may produce euphoria by relieving pain -- a euphoria that, because of the way it is produced, does not form the basis of morbid seek orientation, habituation, physical dependence, or addiction.  Foremost amongst these are nefopam, orphenadrine, and perhaps phenyltoloxamine and/or some other antihistamines.  The remainder of analgesics work peripherally.  Research is starting to show that morphine and related drugs may indeed have peripheral effects as well, such as morphine gel working on burns, but peripherally-acting analgesics include aspirin, paracetamol, ibuprofen and the like.
Many of the alkaloids and other derivatives of the opium poppy are not opioids or narcotics; the best example is the smooth-muscle relaxant papaverine. Noscapine is a marginal case as it does have CNS effects but not necessarily similar to morphine, and it is probably in a category all its own.
Finally, some opioids such as diphenoxylate do not possess analgesic action, narcotic or otherwise.
Optical imaging
Optical imaging is a scientific imaging  technique   using visible or infrared light. Optical imaging systems may be divided to the diffusive  and ballistic imaging  systems.

# Diffusive Optical Imaging in Neuroscience
Diffusive Optical imaging may refer to a recent technique that gives cognitive neuroscientists the ability to simultaneously obtain information about the source of neural activity as well as its time course.  In other words, it allows them to "see" neural activity and study the functioning of the brain.
In this method, a laser source of near infrared light is positioned on the scalp.  Detectors composed of optic fiber bundles are located a few centimeters away from the light source.  These detectors sense how the path of light is altered, either through absorption or scattering, as it traverses brain tissue.
This method can provide two types of information.  First, it can be used to measure the absorption of light, which is related to concentration of chemicals in the brain.  Second, it can measure the scattering of light, which is related to physiological characteristics such as the swelling of glia and neurons that are associated with neuronal firing.
Important chemicals that this method can detect include hemoglobin and chytochromes.

# Ballistic  Optical Imaging
These systems ignore the diffused photons and rely only on the Ballistic photons to create high-resolution (near diffraction limit) images through scattering media.
Orexin receptor
The orexin receptor (also referred to as the hypocretin receptor) is a G-protein-coupled receptor that binds the neuropeptide orexin.  There are two variants, OX1 and OX2, each encoded by a different gene (HCRTR1, HCRTR2).
Both orexin receptors exhibit a similar pharmacology - the 2 orexin peptides, orexin-A and orexin-B, bind to both receptors and, in each case, agonist binding results in an increase in intracellular calcium levels. However, orexin-B shows a 10-fold selectivity for orexin receptor type 2, whilst orexin-A is equipotent at both receptors.
Several orexin receptor antagonists are in development for potential use in sleep disorders.

# Synthetic ligands
Several drugs acting on the orexin system are under development, either orexin agonists for the treatment of conditions such as narcolepsy, or orexin antagonists for insomnia. No neuropeptide agonists are yet available, although synthetic Orexin-A polypeptide has been made available as a nasal spray and tested on monkeys. One non-peptide antagonist is currently available in the U.S., Merck's suvorexant (Belsomra),; two additional agents are in development: SB-649,868 by GlaxoSmithKline, for sleep disorders, and ACT-462206, currently in human clinical trials. Another drug in development, almorexant (ACT-078573) by Actelion, was abandoned due to adverse effects.
Most ligands acting on the orexin system so far are polypeptides modified from the endogenous agonists Orexin-A and Orexin-B, however there are some subtype-selective non-peptide antagonists available for research purposes.
- SB-334,867  selective OX1 antagonist
- SB-408,124  selective OX1 antagonist
- TCS-OX2-29  selective OX2 antagonist
- EMPA (N-Ethyl-2--N-pyridin-3-ylmethyl-acetamide)   selective OX2 antagonist
- RTIOX-276  selective OX1 antagonist
Organopalladium
Organopalladium chemistry is a branch of organometallic chemistry that deals with organic palladium compounds and their reactions. Palladium is often used as a catalyst in the reduction of alkenes and alkynes with hydrogen. This process involves the formation of a palladium-carbon covalent bond. Palladium is also prominent in carbon-carbon coupling reactions, as demonstrated in tandem reactions .

# Organopalladium chemistry timeline.
- 1873 - A. N. Zaitsev reports reduction of benzophenone over palladium with hydrogen.
- 1894 - Phillips reports that palladium(II) chloride reduces to palladium metal by contact with ethylene .
- 1907 - Autoclave technology introduced by W. Ignatieff makes it possible to carry out high pressure hydrogenation.
- 1956 - In the Wacker process  ethylene and oxygen react to acetaldehyde with catalyst PdCl2/CuCl2
- 1972 - The Heck reaction   is a coupling reaction of a halogenide with an olefine. The catalyst is Pd(0).
- 1973 - The Trost asymmetric allylic alkylation is a nucleophilic substitution.
- 1975 - The Sonogashira coupling is a coupling reaction of terminal alkynes with aryl or vinyl halides.

# Overview
In contrast to its next-door neighbors the group 11 elements, the element palladium in organic chemistry does not involve preparation of organopalladium compounds itself but rather organopalladium reactive intermediates . On top of that in many reactions only catalytical amounts of the metal are used.

## Pd Alkene complexes
Palladium reacts with alkenes to form a pi complex which can react with a multitude of nucleophiles akin a oxymercuration reaction. The C-Pd bond is then removed by a reduction or an elimination.  In the industrially important Wacker process, ethylene is converted to acetaldehyde with palladium chloride.

## Pd Allyl complexes
Allyl compunds with suitable leaving groups react with palladium(II) salts to pi-allyl complexes having hapticity 3 such as the Allylpalladium chloride dimer. These intermediates too react with nucleophiles for example carbanions derived from malonates 
Allylpalladium intermediates also feature in the Trost asymmetric allylic alkylation and the Carroll rearrangement and an oxo variation in the Saegusa oxidation.

## Pd insertion compounds
Zerovalent Pd(0) compounds such as tris(dibenzylideneacetone)dipalladium(0) and tetrakis(triphenylphosphine)palladium(0) react with halocarbon R-X in oxidative addition to R-Pd-X intermediates with covalent Pd-C bonds. This chemistry forms the basis of a large class of organic reactions called coupling reactions. Palladium(II) trifluoroacetate has been demonstrated to be effective in aromatic decarboxylation :
In the proposed reaction mechanism Pd(II) replaces the carboxylic acid proton while losing a TFA group, carbon dioxide is lost in a first order reaction and TFA destroys the formed Ar-Pd-TFA complex without Pd changing its oxidation state.
Ovarian fibroma
Contributors:  Cafer Zorkun M.D., PhD.

# Overview
Ovarian fibromas account for approximately 4% of all ovarian neoplasms and are the most common sex cord tumor. Fibromas are generally asymptomatic and typically detected in middle-aged women at palpation during routine gynecologic examination. They are associated with ascites in 40% of cases and with pleural effusions in a small percentage of cases. Meig syndrome consists of an ovarian fibroma with ascites and a pleural effusion.  

# Epidemiology
Fibromas are seen in 75% of patients with nevoid basal cell carcinoma syndrome.

# Diagnosis

## Ultrasonography
Fibromas most commonly manifest as solid, hypoechoic masses with sound attenuation;  however, the US appearance is variable.

## Computed Tomography
Fibromas manifest as diffuse, slightly hypoattenuating masses with poor, very slow contrast enhancement.

## Magnetic Resonance Imaging
Fibromas demonstrate homogeneous, relatively low signal intensity on T1-weighted MR images. On T2-weighted images, fibromas appear as well-circumscribed masses with low signal intensity containing scattered high-signal-intensity areas representing edema or cystic degeneration.

# Diagnostic Findings

## Ultrasonography
Images courtesy of RadsWiki
- US: Ovarian fibroma.
- US: Ovarian fibroma.

## Magnetic Resonance Imaging
Images courtesy of RadsWiki
- MRI: Ovarian fibroma.
- MRI: Ovarian fibroma.
- MRI: Ovarian fibroma.
- MRI: Ovarian fibroma.
- MRI: Ovarian fibroma.

## Pathology
- Ovarian Fibroma
Ovum avtivation
Ovum activation is the events which occur after fertilisation.
Sperm entry causes calcium release into the oocyte. This is caused by the prescence of PLCzeta from the sperm cytoplasm. Activation of the ovum causes the following events
- Cortical reaction
- Reactivation of meiosis
- DNA synthesis

# Cortical Reaction

# Reactivation of meiosis
The meotic cycle of the oocyte was suspended in metaphase of the second meiotic division. Calcium release causes reactivation of the cycle. This results in the production and extrusion of the second polar body.

# DNA synthesis
4 hours after fusion of sperm and ovum, DNA synthesis begins. Male and female pronuclei move to the centre of the egg and membranes break down. Male protamine and replaced with histones and the male DNA is demethylated. Chromosomes then orientate on the metaphase spindle for mitosis. This combination of the two genomes is called syngamy.
The sperm contributes a pronucleus and a centriole to the egg. Most other components and organelles are rapidly degraded. Mitochondria are rapidly ubiquinated and destroyed. Oxidative stress theory is a hypothesis that it is evolutionarily favourable for mitochondria from the father to be destroyed, as it there is a greater possibility that the mitochondrial DNA has become mutated or damaged. This is because mtDNA is not protected by histones and has poor repair mechanisms. Due to the increased metabolic activity of the sperm compared to the egg, due to its motility, there is greater production of reactive oxygen species and therefore greater chance of mutation. Furthermore, sperm are exposed to reactive oxygen species from leukocytes in the epididymis during transit. Additionally, quality control of spermatozoa is much worse than for the ovum, as many sperm are released whereas only one dominant follicle is released per cycle. This competitive selection helps to ensure the most 'fit' ova are selected for fertilisation.
PARTNER 2 Trial

# Objective
To compare the outcomes with transcatheter aortic valve replacement (TAVR) versus surgical valve replacement among intermediate-risk patients with severe aortic stenosis

# Methods
The Placement of Aortic Transcatheter Valves (PARTNER) 2 trial was a prospective, multicenter, randomized, active-treatment-controlled clinical trial comparing transcatheter aortic-valve replacement with surgical aortic valve replacement in intermediate-risk patients with severe aortic stenosis.
Intermediate-risk patient: defined by a Society of Thoracic Surgeons (STS) risk score of at least 4/0%; the upper limit applied by the care review committee was 8.0% (not prespecified). Patients with a score of less than 4.0% were enrolled if they had coexisting conditions that were not included in the risk model.
Patients were randomly assigned to two groups:
- Surgical aortic valve replacement
- Transcatheter aortic valve implantation (either a transfemoral or a transthoracic approach)
Study device: The balloon-expandable SAPIEN XT heart-valve system (Edwards Lifesciences)
The primary endpoint: The primary endpoint was a non hierarchical composite of death from any cause or disabling stroke at 2 years

# Results
A total of 2034 intermediate-risk patients were enrolled at 57 centers. There was no significant difference in the rate of death from any cause or disabling stroke at 2 years between two groups (P=0.001 for noninferiority). At 2 years, the KaplanMeier event rates were 19.3% in the TAVR group and 21.1% in the surgery group (hazard ratio in the TAVR group, 0.89; 95% confidence interval , 0.73 to 1.09; P=0.25). In the transfemoral-access cohort, TAVR resulted in a lower rate of mortality or disabling stroke (hazard ratio, 0.79; 95% CI, 0.62 to 1.00; P=0.05), while in the transthoracic-access cohort, the outcomes were comparable in both groups. TAVR was associated with lower rates of acute kidney injury (1.3% vs. 3.1%, P=0.006), life-threatening bleeding (10.4% vs. 43.4%, P<0.001), and new-onset atrial fibrillation (9.1% vs. 26.4%, P<0.001). At 30 days, Surgery was associated with fewer major vascular complications (5.0% vs.7.9, P=0.008) and less paravalvular aortic regurgitation. Patients in the TAVR group had fewer cardiac symptoms at 30 days compared with the surgery group (P=0.001), but the difference was insignificant at subsequent times. TAVR was associated with a significantly shorter duration of intensive care unit (ICU) stay (median, 2 vs. 4 days; P<0.001), as well as a shorter index hospitalization (median, 6 vs. 9 days; P<0.001).

# Conclusion
In intermediate-risk patients with severe aortic stenosis, TAVR and surgical aortic-valve replacement were associated with similar rates of death or disabling stroke (non-inferiority of the transcatheter group, as compared with the surgical group).
Pair production
Pair production refers to the creation of an elementary particle and its antiparticle, usually from a photon (or another neutral boson). This is allowed, provided there is enough energy available to create the pair  at least the total rest mass energy of the two particles  and that the situation allows both energy and momentum to be conserved (though not necessarily on shell). All other conserved quantum numbers (angular momentum, electric charge) of the produced particles must sum to zero  thus the created particles shall have opposite values of each (for instance, if one particle has strangeness +1 then another one must have strangeness 1).
In nuclear physics, this occurs when a high-energy photon interacts with an atomic nucleus, allowing it to produce an electron and a positron without violating conservation of momentum. Since the momentum of the initial photon must be absorbed by something, pair production cannot occur in empty space out of a single photon; the nucleus is needed to conserve both momentum and energy.
Pair production can only occur if the photon has an energy exceeding the twice the rest mass(me) of an electron (1.022 MeV); the same applies for the generation of other higher energy leptons such as the muon and tau.  These interactions were first observed in Patrick Blackett's counter-controlled bubble chamber, leading to the 1948 Nobel Prize in Physics.
In semiclassical general relativity, pair production is also invoked to explain the Hawking radiation effect. According to quantum mechanics, at short scales short-lived particle-pairs are constantly appearing and disappearing (see quantum foam); in a region of strong gravitational tidal forces, the two particles in a pair may sometimes be wrenched apart before they have a chance to mutually annihilate. When this happens in the region around a black hole, one particle may escape, with its antiparticle being captured by the hole.
Pair production is also the hypothesized mechanism behind the Pair instability supernova type of stellar explosions, where pair production suddenly lowers pressure inside a supergiant star, leading to a partial implosion, and then explosive thermonuclear burning.  Supernova SN 2006gy is hypothesized to have been a pair production type supernova.