Persius/hicric huggingface dataset:
Pentafluoroethane

# Overview
Pentafluoroethane, also called 1,1,1,2,2-pentafluoroethane, HFC-125, or R-125, is a refrigerant that has zero ozone depletion potential.  It has the formula CF3CHF2.
Pentafluoroethane in an azeotropic mixture with difluoromethane is known as R-410A, a common replacement for various chlorofluorocarbons (aka Freon) in new refrigerant systems.
Although it has zero ozone depletion potential, it has high global warming potential, 3400 times that of carbon dioxide, based on a 100-year time frame ].
Pentafluoroethane is also used as a fire suppression agent in fire suppression systems.

# Fire suppression systems
HFC-125 can be used in clean agent fire suppression systems. The HFC-125 clean agent is stored in a pressurized container and introduced into the hazard as a gas.  The agent is odorless, colorless, electrically non-conductive, non-corrosive, and leaves no residue.  It is used in occupied enclosed areas that contain high-value assets.
HFC-125 suppresses fire by absorbing heat energy at its molecular level faster than the heat can be generated, so the fire cannot sustain itself. It also forms free radicals to chemically interfere with the chain reaction of the combustion process.  This makes it a highly effective fire fighting agent that is safe for people and causes no damage to equipment.
When introduced to the market HFC-125 was not considered safe for use in occupied spaces. The US EPA SNAP (Significant New Alternative Policy) listing reflected this. Following the introduction and acceptance of the PBPK model in the NFPA standard NFPA 2001 Standard on Clean Agent Fire Extinguishing Systems 2004 Edition, the restriction was relaxed and now HFC-125 can be used in occupied hazards. Generally, class B (flammable liquid) hazards require concentrations that exceed the agent NOAEL so extra precautions must be taken to avoid prolonged exposure to the agent.
Perforated septum

# Overview
A perforated septum is a medical condition whereby the septum, the cartilaginous membrane dividing the nostrils, develops a hole or fissure.

# Causes
- Cocaine
- Leprosy
- Nosebleed (epistaxis)
- Body piercing
- Rhinoplasty complication
- Wegener's granulomatosis.

# Natural History, Complications, Prognosis
Perforated septum result in breathing noises and may lead to recurrent nose bleeds.

# Treatment
A perforated septum can be closed. The technique most frequently used is the mucosal bridge flap.
Perilymph fistula
A labyrinthine fistula (or perilymph fistula) is leakage of inner ear fluid into the air filled middle ear.
It is a cause of balance disorders and can be a complication of a stapedectomy.
ABBREVIATIONS
VZV= Varicella zoster virus, MRI= Magnetic resonance imaging, ESR= Erythrocyte sedimentation rate, EEG= Electroencephalogram, CSF= Cerebrospinal fluid, GPe= Globus pallidus externa, ICHD=  International Classification of Headache Disorders
Period prevalence
Assistant Editor(s)-In-Chief: Kristin Feeney, B.S.

# Overview
In epidemiology, Period prevalence is the proportion of the population with a given disease or condition over a specific period of time. It could describe how many people in a population had a cold over the cold season in 2006, for example.

# Calculation
It is expressed as a percentage of the population and can be described by the following formula:
Period prevalence (ratio) = Number of cases that occurred in a given period  Number of people in the population during this period
The relationship between incidence (rate), point prevalence (ratio) and period prevalence (ratio) is easily explicated via an analogy with photography. Point prevalence is akin to a flashlit photograph: what is happening at this instant frozen in time. Period prevalence is analogous to a long exposure (seconds, rather than an instant) photograph: the number of events recorded in the photo whilst the camera shutter was open. In a movie each frame records an instant (point prevalence); by looking from frame to frame one notices new events (incident events) and can relate the number of such events to a time period (number of frames) -> incidence rate.

# Critical Consideration
- A ratio is one number divided by another.
- A rate entails reference to the passage of time: miles per hour, new cases per year (incidence), etc.
- A rate is necessarily a ratio but not vice versa.

# Related Chapters
- Point prevalence
Periodontal probe

# Overview
A periodontal probe is an instrument in dentistry commonly used in the dental armamentarium.  It is usually long, thin, and blunted at the end.  The primary purpose of a periodontal probe is to measure pocket depths around a tooth in order to establish the state of health of the periodontium.  There are markings inscribed onto the head of the instrument to make measurements more accurate and easier for a dentist.
Proper use of the periodontal probe is necessary to maintain accuracy.  The tip of the instrument is placed with light pressure into the gingival sulcus, which is an area of potential space between a tooth and the surrounding tissue.  It is important to keep the periodontal probe parallel to the contours of the root of the tooth and to insert the probe down to the base of the pocket.  This results in obscuring a section of the periodontal probe's tip.  The first marking visible above the pocket indicates the measurement of the pocket depth.  It has been found that the average, healthy pocket depth is around 3 mm.  Depths greater than 3 mm can be associated with "attachment loss" of the tooth to the surrounding alveolar bone, which is a characteristic found in periodontitis.  Pocket depths greater than 3 mm can also be a sign of gingival hyperplasia.
There are many different types of periodontal probes, and each has its own manner of indicating measurements on the tip of the instrument.  For example, the Michigan O probe with Williams markings has circumferential lines at 1 mm, 2 mm, 3 mm, 5 mm, 7 mm, 8 mm, 9 mm, and 10 mm.  The PCP12 probe with Marquis markings has alternating shades every 3 mm.  Unlike the previous two mentioned, the Naber's probe is curved, and it is used for measuring into the furcation area between the roots of a tooth.
The periodontal probe can also be used to measure other dental instruments and tooth preparations during restorative procedures.
Periplasmic space
The periplasmic space is the space seen between the plasma membrane and the outer membrane in the gram-negative bacteria. A very small periplasmic space between the plasma membrane and the peptidoglycan layer (cell wall) may be observed in the gram-positive bacteria (Zuber et al., 2006). The periplasmic space is a lot thicker in Gram negative bacteria. Periplasmic space may be filled with a loose network of peptidoglycan and may constitute up to 40% of the total cell volume. This space is involved in various biochemical pathways including nutrient acquisition, synthesis of peptidoglycan, electron transport, and alteration of substances toxic to the cell. Gram-positive bacteria do not have as many periplasmic proteins compared to the gram-negative bacteria. Instead gram-positive bacteria secrete enzymes which would normally be found in the periplasmic space of the gram-negative bacteria. This secreted enzyme is referred to as an exoenzyme. Substance that occupies the periplasmic space is referred to as a periplasm.
The periplasmic space is of particular clinical importance in that it is the site, in some species, that contains beta-lactamase, an enzyme responsible for degrading the penicillin group of antibiotic drugs, leading to penicillin resistance.
References:
- D. White, The Physiology and Biochemistry of Prokaryotes, Oxford University Press, Oxford, 2000, pp. 22.
-  Zuber, B.,  Haenni, M., Ribeiro, T., Minnig, K., Lopes, F., Moreillon, P., Dubochet, J. 2006. Granular layer in the Periplasmic space of Gram-Positive bacteria and fine structures of Enterococcus gallinarum and Streptococcus gordonii septa revealed by Cryo-Electron Microscopy of vitreous sections.  J. Bacteriol. Sept.;188 (18):6652-60
de:Periplasmatischer Raum
Personality style
Personality style has been defined as "an individual's relatively consistent inclinations and  preferences across contexts."
Personality can be defined as a dynamic and organized set of personal  traits and patterns of behavior. "Personality includes  attitudes, modes of thought,  feelings,  impulses, strivings,  actions, responses to opportunity and  stress and everyday modes of  interacting with others." Personality style is apparent "when these elements of personality are expressed in a characteristically repeated and dynamic combination."
According to Oldham and Morris, "Your personality style is your organizing principle. It propels you on your life path. It represents the orderly arrangement of all your attributes, thoughts, feelings, attitudes, behaviors, and  coping mechanisms. It is the distinctive pattern of your psychological functioningthe way you think, feel, and behavethat makes you definitely you."
The origin of personality style is in some combination of genetic inheritance and  environmental influence.
The concept of personality style is broader than and includes the concepts of "personality traits", "personality type", and "temperament".
Personality style is usually represented dimensionally, as with the Big Five personality traits, or as a classification of type, as with the Holland Codes.
"Personality styles should be recognized as constructed approximations of human experience" and should be arrayed on a continuum rather than be  reifed or totalized. One should be vigilant to  deconstruct the uses of personality style in favor of an ongoing  reflexivity about the use and misuse of such  labels.
McAuliffe, Eriksen and Kress contrast personality style theory with stage theory. Style "represents long-term constructive preferences whereas stage represents current constructive capacity." Also, "style is relatively long-term and consistent over time, whereas stage tendencies are mutable..."
Personality style  assessment can help individuals and practitioners appreciate human diversity, or, in the words of Isabel Briggs Myers, respect "gifts differing".
"The range of normal variation in styles can explain much human behavior without reference to notions of  pathology." Personality disorders can be reconceptualized as being on a continuum, with one end being a more adaptive inclination. And style assessment can also compliment the search for personality disorder.
Specific personality style theories that might be useful include Costa and McCrae's  NEO PI-R personality inventory,  Holland's person-environment matching theory, Isabel Briggs Myers'  personality type theory,  Oldham and Morris' derivation of personality styles from  DSM personality disorders,  and Ivey's reconceptualization of the DSM personality disorders as a continuum of personality styles.
Petroleum product
Petroleum products are useful materials derived from crude oil (petroleum) as it is processed in oil refineries.
According to crude oil composition and demand, refineries can produce different shares of petroleum products. Largest share of oil products is used as energy carriers: various grades of fuel oil and gasoline. Refineries also produce other chemicals, some of which are used in chemical processes to produce plastics and other useful materials.  Since petroleum often contains a couple of percent sulfur, large quantities of sulfur are also often produced as a petroleum product.  Hydrogen and carbon in the form of petroleum coke may also be produced as petroleum products.  The hydrogen produced is often used as an intermediate product for other oil refinery processes such as hydrogen catalytic cracking (hydrocracking) and hydrodesulfurization.

# Major products of oil refineries

# Specialty end products
Oil refineries will blend various feedstocks, mix appropriate additives, provide short term storage, and prepare for bulk loading to trucks, barges, product ships, and railcars.
- Gaseous fuels such as propane, stored and shipped in liquid form under pressure in specialized railcars to distributors.
- Liquid fuels blending (producing automotive and aviation grades of gasoline, kerosene, various aviation turbine fuels, and diesel fuels, adding dyes, detergents, antiknock additives, oxygenates, and anti-fungal compounds as required). Shipped by barge, rail, and tanker ship. May be shipped regionally in dedicated pipelines to point consumers, particularly aviation jet fuel to major airports, or piped to distributors in multi-product pipelines using product separators called pipeline inspection gauges ("pigs").
- Lubricants (produces light machine oils, motor oils, and greases, adding viscosity stabilizers as required), usually shipped in bulk to an offsite packaging plant.
- Wax (paraffin), used in the packaging of frozen foods, among others. May be shipped in bulk to a site to prepare as packaged blocks.
- Sulfur (or sulfuric acid), byproducts of sulfur removal from petroleum which may have up to a couple percent sulfur as organic sulfur-containing compounds.  Sulfur and sulfuric acid are useful industrial materials.  Sulfuric acid is usually prepared and shipped as the acid precursor oleum.
- Bulk tar shipping for offsite unit packaging for use in tar-and-gravel roofing or similar uses.
- Asphalt - used as a binder for gravel to form asphalt concrete, which is used for paving roads, lots, etc. An asphalt unit prepares bulk asphalt for shipment.
- Petroleum coke, used in specialty carbon products such as certain types of electrodes, or as solid fuel.
- Petrochemicals or petrochemical feedstocks, which are often sent to petrochemical plants for further processing in a variety of ways.  The petrochemicals may be olefins or their precursors, or various types of aromatic petrochemicals.
Phalen's maneuver
Synonyms and keywords: Phalen's sign; Phalen's test

# Overview
Phalen's maneuver is a diagnostic test for  carpal tunnel syndrome in which the patient is asked to hold their wrist in complete and forced flexion (pushing the dorsal surfaces of both hands together) for 3060 seconds. This maneuver moderately increases the pressure in the carpal tunnel and has the effect of pinching the median nerve between the  proximal edge of the transverse carpal ligament and the anterior border of the distal end of the  radius. By compressing the median nerve within the carpal tunnel, characteristic  symptoms (such as burning, tingling or numb sensation over the thumb, index, middle and ring fingers) conveys a positive test result and confirms carpal tunnel syndrome.

# Historical Perspective
The test was described by an American orthopedist named George S. Phalen.

# Sensitivity and Specificty
The sensitivity of the Phalen's maneuver ranges from 51% to 91% and its specificity from 33% to 88% in studies.

# Reverse Phalen's Test
This test is performed by having the patient maintain full wrist and finger extension for two minutes. The reverse Phalen's test significantly increases pressure in the carpal tunnel within 10 seconds of the change in wrist posture and the carpal tunnel pressure has the tendency to increase throughout the test's duration. In contrast, the change in carpal tunnel pressure noted in the standard Phalen's test is modest and plateaus after 20 to 30 seconds.
The average pressure change for Phalen's test at one and two minutes was only 4 mm Hg. The average pressure changes in the carpal tunnel for the reverse Phalen's test were 34 mm Hg at one minute into the test and 42 mm Hg at the two minute point.
The extended wrist posture significantly changes the pressure within the carpal tunnel and may be more useful as a provocative examination maneuver. Reverse Phalen's maneuver results in a significantly higher intracarpal canal hydrostatic pressure as compared to a traditional Phalen's.  This is thought to add to the sensitivity of conventional screening methods.

# Comparison
Phalen's maneuver is more  sensitive than Tinel's sign.
Phenylacetic acid
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Phenylacetic acid (abr. PAA and synonyms are: -toluic acid, benzeneacetic acid, alpha tolylic acid, 2-phenylacetic acid) is an organic compound containing a phenyl functional group and an acetic acid functional group. It is a white solid with a disagreeable odor. Because it is used in the illicit production of phenylacetone, it is subject to controls in the United States.

# Significance
Phenylacetic acid has been found to be an active auxin (a type of plant hormone) molecule, predominantly found in fruits. However its effect is much weaker than the effect of the basic auxin molecule indole-3-acetic acid.
Phenylacetic acid is used in some perfumes, possessing a honey-like odour in low concentrations, and is also used in penicillin G production.
Its refractive index is 1.5025.
Phlegmon overview

# Overview
Phlegmon is a spreading diffuse inflammatory process with formation of suppurative/purulent exudate or pus.

# Pathophysiology
Factors affecting the development of phlegmons are virulence of bacteria and human's immunity strength defenses.

# Causes
Phlegmon is commonly caused by bacteria - staphylococci, streptococci, pneumococci, spore and non-spore forming anaerobes, etc.

# Diagnosis

## History and Symptoms
Systemic features of infection like increased body temperature (up to 38-40C), general fatigue, chills, sweatings, headache, and loss of appetite may be present.

## Physical Examination
Inflammatory signs - dolor (localized pain), calor (increase local tissue temperature), rubor (skin redness/hyperemia), tumor (either clear or non-clear bordered tissue swelling), functio laesa (diminish affected function) may be present. Severity of patient condition with phlegmons is directly proportional to the degree of intoxication level i.e the severe the condition, the higher degree of intoxication level.

## Laboratory Findings
The main goal of treatment is to remove the cause of phlegmonous process in order to achieve effective treatment and prevention of recurrence. If patients condition is mild and the signs of inflammatory process is presence without signs of infiltrates, then conservative treatment with antibiotics is sufficient.

# Treatment

## Medical Therapy
The main goal of treatment is to remove the cause of phlegmonous process in order to achieve effective treatment and prevention of recurrence. If patients condition is mild and the signs of inflammatory process is presence without signs of infiltrates, then conservative treatment with antibiotics is sufficient.
Pineal gland cyst

# Overview
A pineal gland cyst is a cyst in the pineal gland, a small endocrine gland in the brain..  Statisically, these fluid-filled bodies appear on 1-4% of magnetic resonance imaging (MRI) brain scans.  They are more frequent at death, seen in 21-41% of autopsies, though researchers are not sure why.  They are in most cases asymptomatic, and it is rare for a pineal cyst to cause symptoms.  If they do, these would most likely be headache, visual disturbances, or hydrocephalus, which can be extremely dangerous if left untreated. Pineal cysts are not cancer and most of the time they do not enlarge over 2 centimeters.
Asymptomatic cysts require no treatment. Some doctors choose to monitor patients with CT scans or MRI to look for cyst growth, but most doctors do not.

# Differentiating Pineal gland cyst from Other Diseases
- Pineal cysts are most often mistaken for and may be indistinguishable from a benign pineocytoma. Pineocytomas are more likely to have solid components.
- Other cysts in the quadrigeminal cistern that mimic pineal cysts include arachnoid cysts and, rarely, epidermoids.

# Diagnosis
- Attenuation or signal intensity varies with cyst content.
- One-fourth have rim or nodular calcium in the cyst wall on nonenhanced CT scans.
- Rim or nodular enhancement is also common.
- On T1-weighted MR images, 55%60% are slightly hyperintense to CSF. Most do not appear hypointense on FLAIR images, and 60% enhance with use of contrast material.

# Treatment
Pineocytoma x ray

# Overview
There are no x-ray findings associated with .
OR
An x-ray may be helpful in the diagnosis of . Findings on an x-ray suggestive of/diagnostic of  include , , and .
OR
There are no x-ray findings associated with . However, an x-ray may be helpful in the diagnosis of complications of , which include , , and .

# X Ray
There are no x-ray findings associated with .
OR
An x-ray may be helpful in the diagnosis of . Findings on an x-ray suggestive of/diagnostic of  include:
OR
There are no x-ray findings associated with . However, an x-ray may be helpful in the diagnosis of complications of , which include:
Pirimiphos-methyl

# Overview
Pirimiphos-methyl is a phosphorothioate used as an insecticide.   It was originally developed by Imperial Chemical Industries Ltd., now Syngenta, in 1967.
This is one of several compounds used for vector control of Triatoma. These insects are implicated in the transmission of Chagas disease in the Americas. Pirimiphos-methyl can be applied as an interior surface paint additive, in order to achieve a residual pesticide effect.
Pyrimiphos-ethyl is a related insecticide in which the methyl groups are replaced with ethyl groups.
Plague of Cyprian
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The Plague of Cyprian is the name given to a pandemic, probably of smallpox, that afflicted the Roman Empire from 251 AD onwards. It was still raging in 270, when it claimed the life of emperor Claudius II Gothicus (ruled 268-70). The plague caused widespread manpower shortages in agriculture and the Roman army. It is named after St. Cyprian, an early Christian writer who witnessed and described the plague.
In 251 to 266, at the height of the outbreak, 5,000 people a day were said to be dying in Rome.  Cyprian's biographer, Pontius the deacon, wrote of the plague at Carthage:
As Jews paid with their lives during the 14th century's Black Death, so in Carthage the "Decian persecution" unleashed at the onset of the plague sought out Christian scapegoats. Fifty years later, the North African convert to Christianity Arnobius defended his new religion from pagan allegations:
Cyprian drew moralizing analogies in his sermons to the Christian community and drew a word picture of the plague's symptoms in his essay De mortalitate ("On the Plague"):
Historian William McNeill asserts that the Antonine Plague and the Plague of Cyprian were outbreaks of two different diseases, one of smallpox and one of measles, although not necessarily in that order.  The severe devastation to the European population from the two plagues may indicate that people had no previous exposure - or immunity - to either disease. The modern consensus, however, is that both outbreaks were smallpox.

# Notes
-  Zosimus New History 26, 37, 46
-  Pontius of Carthage Life of Cyprian
-  Cyprian Adversus Gentes 1.3
-  Cyprian De Mortalitate
-  D. Ch. Stathakopoulos Famine and Pestilence in the late Roman and early Byzantine Empire (2007) 95