document_title: X-ray

question_text: when was the x ray first used in medicine

question_tokens: when was the x ray first used in medicine

text: X-ray

text: Energy ranges[edit]

text: Soft and hard X-rays[edit]

text: X-rays with high photon energies (above 5–10 keV, below 0.2–0.1 nm wavelength) are called hard X-rays, while those with lower energy are called soft X-rays.[4] Due to their penetrating ability, hard X-rays are widely used to image the inside of objects, e.g., in medical radiography and airport security. The term X-ray is metonymically used to refer to a radiographic image produced using this method, in addition to the method itself. Since the wavelengths of hard X-rays are similar to the size of atoms they are also useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air; the attenuation length of 600 eV (~2 nm) X-rays in water is less than 1 micrometer.[5]

text: Gamma rays[edit]

text: There is no consensus for a definition distinguishing between X-rays and gamma rays. One common practice is to distinguish between the two types of radiation based on their source: X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus.[6][7][8][9] This definition has several problems: other processes also can generate these high-energy photons, or sometimes the method of generation is not known. One common alternative is to distinguish X- and gamma radiation on the basis of wavelength (or, equivalently, frequency or photon energy), with radiation shorter than some arbitrary wavelength, such as 10−11 m (0.1 Å), defined as gamma radiation.[10] This criterion assigns a photon to an unambiguous category, but is only possible if wavelength is known. (Some measurement techniques do not distinguish between detected wavelengths.) However, these two definitions often coincide since the electromagnetic radiation emitted by X-ray tubes generally has a longer wavelength and lower photon energy than the radiation emitted by radioactive nuclei.[6] Occasionally, one term or the other is used in specific contexts due to historical precedent, based on measurement (detection) technique, or based on their intended use rather than their wavelength or source. Thus, gamma-rays generated for medical and industrial uses, for example radiotherapy, in the ranges of 6–20 MeV, can in this context also be referred to as X-rays.[citation needed]

text: Properties[edit]

text: X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds. This makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a short period of time causes radiation sickness, while lower doses can give an increased risk of radiation-induced cancer. In medical imaging this increased cancer risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in cancer treatment to kill malignant cells using radiation therapy. It is also used for material characterization using X-ray spectroscopy.

text: Hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects. The most often seen applications are in medical radiography and airport security scanners, but similar techniques are also important in industry (e.g. industrial radiography and industrial CT scanning) and research (e.g. small animal CT). The penetration depth varies with several orders of magnitude over the X-ray spectrum. This allows the photon energy to be adjusted for the application so as to give sufficient transmission through the object and at the same time provide good contrast in the image.

text: X-rays have much shorter wavelengths than visible light, which makes it possible to probe structures much smaller than can be seen using a normal microscope. This property is used in X-ray microscopy to acquire high resolution images, and also in X-ray crystallography to determine the positions of atoms in crystals.

text: Interaction with matter[edit]

text: X-rays interact with matter in three main ways, through photoabsorption, Compton scattering, and Rayleigh scattering. The strength of these interactions depends on the energy of the X-rays and the elemental composition of the material, but not much on chemical properties, since the X-ray photon energy is much higher than chemical binding energies. Photoabsorption or photoelectric absorption is the dominant interaction mechanism in the soft X-ray regime and for the lower hard X-ray energies. At higher energies, Compton scattering dominates.

text: Photoelectric absorption[edit]

text: The probability of a photoelectric absorption per unit mass is approximately proportional to Z3/E3, where Z is the atomic number and E is the energy of the incident photon.[11] This rule is not valid close to inner shell electron binding energies where there are abrupt changes in interaction probability, so called absorption edges. However, the general trend of high absorption coefficients and thus short penetration depths for low photon energies and high atomic numbers is very strong. For soft tissue, photoabsorption dominates up to about 26 keV photon energy where Compton scattering takes over. For higher atomic number substances this limit is higher. The high amount of calcium (Z=20) in bones together with their high density is what makes them show up so clearly on medical radiographs.

text: A photoabsorbed photon transfers all its energy to the electron with which it interacts, thus ionizing the atom to which the electron was bound and producing a photoelectron that is likely to ionize more atoms in its path. An outer electron will fill the vacant electron position and produce either a characteristic photon[clarification needed] or an Auger electron. These effects can be used for elemental detection through X-ray spectroscopy or Auger electron spectroscopy.

text: Compton scattering[edit]

text: Compton scattering is the predominant interaction between X-rays and soft tissue in medical imaging.[12] Compton scattering is an inelastic scattering of the X-ray photon by an outer shell electron. Part of the energy of the photon is transferred to the scattering electron, thereby ionizing the atom and increasing the wavelength of the X-ray. The scattered photon can go in any direction, but a direction similar to the original direction is more likely, especially for high-energy X-rays. The probability for different scattering angles are described by the Klein–Nishina formula. The transferred energy can be directly obtained from the scattering angle from the conservation of energy and momentum.

text: Rayleigh scattering[edit]

text: Rayleigh scattering is the dominant elastic scattering mechanism in the X-ray regime.[13] Inelastic forward scattering gives rise to the refractive index, which for X-rays is only slightly below 1.[14]

text: Production[edit]

text: Whenever charged particles (electrons or ions) of sufficient energy hit a material, X-rays are produced.

text: Production by electrons[edit]

text:
Characteristic X-ray emission lines for some common anode materials.[15][16]

Anode
material
Atomic
number
Photon energy [keV]
Wavelength [nm]

Kα1
Kβ1
Kα1
Kβ1

W
74
59.3
67.2
0.0209
0.0184

Mo
42
17.5
19.6
0.0709
0.0632

Cu
29
8.05
8.91
0.154
0.139

Ag
47
22.2
24.9
0.0559
0.0497

Ga
31
9.25
10.26
0.134
0.121

In
49
24.2
27.3
0.0512
0.455

text: X-rays can be generated by an X-ray tube, a vacuum tube that uses a high voltage to accelerate the electrons released by a hot cathode to a high velocity. The high velocity electrons collide with a metal target, the anode, creating the X-rays.[17] In medical X-ray tubes the target is usually tungsten or a more crack-resistant alloy of rhenium (5%) and tungsten (95%), but sometimes molybdenum for more specialized applications, such as when softer X-rays are needed as in mammography. In crystallography, a copper target is most common, with cobalt often being used when fluorescence from iron content in the sample might otherwise present a problem.

text: The maximum energy of the produced X-ray photon is limited by the energy of the incident electron, which is equal to the voltage on the tube times the electron charge, so an 80 kV tube cannot create X-rays with an energy greater than 80 keV. When the electrons hit the target, X-rays are created by two different atomic processes:

text:
Characteristic X-ray emission (X-ray fluorescence): If the electron has enough energy it can knock an orbital electron out of the inner electron shell of a metal atom, and as a result electrons from higher energy levels then fill up the vacancy and X-ray photons are emitted. This process produces an emission spectrum of X-rays at a few discrete frequencies, sometimes referred to as the spectral lines. The spectral lines generated depend on the target (anode) element used and thus are called characteristic lines. Usually these are transitions from upper shells into K shell (called K lines), into L shell (called L lines) and so on.
Bremsstrahlung: This is radiation given off by the electrons as they are scattered by the strong electric field near the high-Z (proton number) nuclei. These X-rays have a continuous spectrum. The intensity of the X-rays increases linearly with decreasing frequency, from zero at the energy of the incident electrons, the voltage on the X-ray tube.

text: So the resulting output of a tube consists of a continuous bremsstrahlung spectrum falling off to zero at the tube voltage, plus several spikes at the characteristic lines. The voltages used in diagnostic X-ray tubes range from roughly 20 kV to 150 kV and thus the highest energies of the X-ray photons range from roughly 20 keV to 150 keV.[18]

text: Both of these X-ray production processes are inefficient, with a production efficiency of only about one percent, and thus most of the electric power consumed by the tube is released as waste heat. When producing a usable flux of X-rays, the X-ray tube must be designed to dissipate the excess heat.

text: Short nanosecond bursts of X-rays peaking at 15-keV in energy may be reliably produced by peeling pressure-sensitive adhesive tape from its backing in a moderate vacuum. This is likely to be the result of recombination of electrical charges produced by triboelectric charging. The intensity of X-ray triboluminescence is sufficient for it to be used as a source for X-ray imaging.[19]

text: A specialized source of X-rays which is becoming widely used in research is synchrotron radiation, which is generated by particle accelerators. Its unique features are X-ray outputs many orders of magnitude greater than those of X-ray tubes, wide X-ray spectra, excellent collimation, and linear polarization.[20]

text: Production by fast positive ions[edit]

text: X-rays can also be produced by fast protons or other positive ions. The proton-induced X-ray emission or particle-induced X-ray emission is widely used as an analytical procedure. For high energies, the production cross section is proportional to Z12Z2−4, where Z1 refers to the atomic number of the ion, Z2 to that of the target atom.[21] An overview of these cross sections is given in the same reference.

text: Detectors[edit]

text: X-ray detectors vary in shape and function depending on their purpose. Imaging detectors such as those used for radiography were originally based on photographic plates and later photographic film, but are now mostly replaced by various digital detector types such as image plates and flat panel detectors. For radiation protection direct exposure hazard is often evaluated using ionization chambers, while dosimeters are used to measure the radiation dose a person has been exposed to. X-ray spectra can be measured either by energy dispersive or wavelength dispersive spectrometers.

text: Medical uses[edit]

text: Since Röntgen's discovery that X-rays can identify bone structures, X-rays have been used for medical imaging. The first medical use was less than a month after his paper on the subject.[22] Up to 2010, 5 billion medical imaging examinations had been conducted worldwide.[23] Radiation exposure from medical imaging in 2006 made up about 50% of total ionizing radiation exposure in the United States.[24]

text: Projectional radiographs[edit]

text: Projectional radiography is the practice of producing two-dimensional images using x-ray radiation. Bones contain much calcium, which due to its relatively high atomic number absorbs x-rays efficiently. This reduces the amount of X-rays reaching the detector in the shadow of the bones, making them clearly visible on the radiograph. The lungs and trapped gas also show up clearly because of lower absorption compared to tissue, while differences between tissue types are harder to see.

text: Projectional radiographs are useful in the detection of pathology of the skeletal system as well as for detecting some disease processes in soft tissue. Some notable examples are the very common chest X-ray, which can be used to identify lung diseases such as pneumonia, lung cancer, or pulmonary edema, and the abdominal x-ray, which can detect bowel (or intestinal) obstruction, free air (from visceral perforations) and free fluid (in ascites). X-rays may also be used to detect pathology such as gallstones (which are rarely radiopaque) or kidney stones which are often (but not always) visible. Traditional plain X-rays are less useful in the imaging of soft tissues such as the brain or muscle.

text: Dental radiography is commonly used in the diagnoses of common oral problems, such as cavities.

text: In medical diagnostic applications, the low energy (soft) X-rays are unwanted, since they are totally absorbed by the body, increasing the radiation dose without contributing to the image. Hence, a thin metal sheet, often of aluminium, called an X-ray filter, is usually placed over the window of the X-ray tube, absorbing the low energy part in the spectrum. This is called hardening the beam since it shifts the center of the spectrum towards higher energy (or harder) x-rays.

text: To generate an image of the cardiovascular system, including the arteries and veins (angiography) an initial image is taken of the anatomical region of interest. A second image is then taken of the same region after an iodinated contrast agent has been injected into the blood vessels within this area. These two images are then digitally subtracted, leaving an image of only the iodinated contrast outlining the blood vessels. The radiologist or surgeon then compares the image obtained to normal anatomical images to determine whether there is any damage or blockage of the vessel.

text: Computed tomography[edit]

text: Computed tomography (CT scanning) is a medical imaging modality where tomographic images or slices of specific areas of the body are obtained from a large series of two-dimensional X-ray images taken in different directions.[25] These cross-sectional images can be combined into a three-dimensional image of the inside of the body and used for diagnostic and therapeutic purposes in various medical disciplines.

text: Fluoroscopy[edit]

text: Fluoroscopy is an imaging technique commonly used by physicians or radiation therapists to obtain real-time moving images of the internal structures of a patient through the use of a fluoroscope. In its simplest form, a fluoroscope consists of an X-ray source and a fluorescent screen, between which a patient is placed. However, modern fluoroscopes couple the screen to an X-ray image intensifier and CCD video camera allowing the images to be recorded and played on a monitor. This method may use a contrast material. Examples include cardiac catheterization (to examine for coronary artery blockages) and barium swallow (to examine for esophageal disorders).

text: Radiotherapy[edit]

text: The use of X-rays as a treatment is known as radiation therapy and is largely used for the management (including palliation) of cancer; it requires higher radiation doses than those received for imaging alone. X-rays beams are used for treating skin cancers using lower energy x-ray beams while higher energy beams are used for treating cancers within the body such as brain, lung, prostate, and breast.[26][27]

text: Adverse effects[edit]

text: Diagnostic X-rays (primarily from CT scans due to the large dose used) increase the risk of developmental problems and cancer in those exposed.[28][29][30] X-rays are classified as a carcinogen by both the World Health Organization's International Agency for Research on Cancer and the U.S. government.[23][31] It is estimated that 0.4% of current cancers in the United States are due to computed tomography (CT scans) performed in the past and that this may increase to as high as 1.5-2% with 2007 rates of CT usage.[32]

text: Experimental and epidemiological data currently do not support the proposition that there is a threshold dose of radiation below which there is no increased risk of cancer.[33] However, this is under increasing doubt.[34] It is estimated that the additional radiation will increase a person's cumulative risk of getting cancer by age 75 by 0.6–1.8%.[35] The amount of absorbed radiation depends upon the type of X-ray test and the body part involved.[36] CT and fluoroscopy entail higher doses of radiation than do plain X-rays.

text: To place the increased risk in perspective, a plain chest X-ray will expose a person to the same amount from background radiation that people are exposed to (depending upon location) every day over 10 days, while exposure from a dental X-ray is approximately equivalent to 1 day of environmental background radiation.[37] Each such X-ray would add less than 1 per 1,000,000 to the lifetime cancer risk. An abdominal or chest CT would be the equivalent to 2–3 years of background radiation to the whole body, or 4–5 years to the abdomen or chest, increasing the lifetime cancer risk between 1 per 1,000 to 1 per 10,000.[37] This is compared to the roughly 40% chance of a US citizen developing cancer during their lifetime.[38] For instance, the effective dose to the torso from a CT scan of the chest is about 5 mSv, and the absorbed dose is about 14 mGy.[39] A head CT scan (1.5mSv, 64mGy)[40] that is performed once with and once without contrast agent, would be equivalent to 40 years of background radiation to the head. Accurate estimation of effective doses due to CT is difficult with the estimation uncertainty range of about ±19% to ±32% for adult head scans depending upon the method used.[41]

text: The risk of radiation is greater to a fetus, so in pregnant patients, the benefits of the investigation (X-ray) should be balanced with the potential hazards to the fetus.[42][43] In the US, there are an estimated 62 million CT scans performed annually, including more than 4 million on children.[36] Avoiding unnecessary X-rays (especially CT scans) reduces radiation dose and any associated cancer risk.[44]

text: Medical X-rays are a significant source of man-made radiation exposure. In 1987, they accounted for 58% of exposure from man-made sources in the United States. Since man-made sources accounted for only 18% of the total radiation exposure, most of which came from natural sources (82%), medical X-rays only accounted for 10% of total American radiation exposure; medical procedures as a whole (including nuclear medicine) accounted for 14% of total radiation exposure. By 2006, however, medical procedures in the United States were contributing much more ionizing radiation than was the case in the early 1980s. In 2006, medical exposure constituted nearly half of the total radiation exposure of the U.S. population from all sources. The increase is traceable to the growth in the use of medical imaging procedures, in particular computed tomography (CT), and to the growth in the use of nuclear medicine.[24][45]

text: Dosage due to dental X-rays varies significantly depending on the procedure and the technology (film or digital). Depending on the procedure and the technology, a single dental X-ray of a human results in an exposure of 0.5 to 4 mrem. A full mouth series of X-rays may result in an exposure of up to 6 (digital) to 18 (film) mrem, for a yearly average of up to 40 mrem.[46][47][48][49][50][51][52]

text: Other uses[edit]

text: Other notable uses of X-rays include

text:
X-ray crystallography in which the pattern produced by the diffraction of X-rays through the closely spaced lattice of atoms in a crystal is recorded and then analysed to reveal the nature of that lattice. A related technique, fiber diffraction, was used by Rosalind Franklin to discover the double helical structure of DNA.[53]
X-ray astronomy, which is an observational branch of astronomy, which deals with the study of X-ray emission from celestial objects.
X-ray microscopic analysis, which uses electromagnetic radiation in the soft X-ray band to produce images of very small objects.
X-ray fluorescence, a technique in which X-rays are generated within a specimen and detected. The outgoing energy of the X-ray can be used to identify the composition of the sample.
Industrial radiography uses X-rays for inspection of industrial parts, particularly welds.

text:
Authentication and quality control, X-ray is used for authentication and quality control of packaged items.
Industrial CT (computed tomography) is a process which uses X-ray equipment to produce three-dimensional representations of components both externally and internally. This is accomplished through computer processing of projection images of the scanned object in many directions.
Paintings are often X-rayed to reveal underdrawings and pentimenti, alterations in the course of painting or by later restorers. Many pigments such as lead white show well in radiographs.
X-ray spectromicroscopy has been used to analyse the reactions of pigments in paintings. For example, in analysing colour degradation in the paintings of van Gogh[55]
Airport security luggage scanners use X-rays for inspecting the interior of luggage for security threats before loading on aircraft.
Border control truck scanners use X-rays for inspecting the interior of trucks.

text:
X-ray art and fine art photography, artistic use of X-rays, for example the works by Stane Jagodič
X-ray hair removal, a method popular in the 1920s but now banned by the FDA.[56]
Shoe-fitting fluoroscopes were popularized in the 1920s, banned in the US in the 1960s, banned in the UK in the 1970s, and even later in continental Europe.
Roentgen stereophotogrammetry is used to track movement of bones based on the implantation of markers
X-ray photoelectron spectroscopy is a chemical analysis technique relying on the photoelectric effect, usually employed in surface science.
Radiation implosion is the use of high energy X-rays generated from a fission explosion (an A-bomb) to compress nuclear fuel to the point of fusion ignition (an H-bomb).

text: History[edit]

text: Discovery[edit]

text: German physicist Wilhelm Röntgen is usually credited as the discoverer of X-rays in 1895, because he was the first to systematically study them, though he is not the first to have observed their effects. He is also the one who gave them the name "X-rays" (signifying an unknown quantity[57]) though many others referred to these as "Röntgen rays" (and the associated X-ray radiograms as, "Röntgenograms") for several decades after their discovery and even to this day in some languages, including Röntgen's native German.

text: X-rays were found emanating from Crookes tubes, experimental discharge tubes invented around 1875, by scientists investigating the cathode rays, that is energetic electron beams, that were first created in the tubes. Crookes tubes created free electrons by ionization of the residual air in the tube by a high DC voltage of anywhere between a few kilovolts and 100 kV. This voltage accelerated the electrons coming from the cathode to a high enough velocity that they created X-rays when they struck the anode or the glass wall of the tube. Many of the early Crookes tubes undoubtedly radiated X-rays, because early researchers noticed effects that were attributable to them, as detailed below. Wilhelm Röntgen was the first to systematically study them, in 1895.[60]

text: The discovery of X-rays stimulated a veritable sensation. Röntgen's biographer Otto Glasser estimated that, in 1896 alone, as many as 49 essays and 1044 articles about the new rays were published.[61] This was probably a conservative estimate, if one considers that nearly every paper around the world extensively reported about the new discovery, with a magazine such as Science dedicating as many as 23 articles to it in that year alone.[62] Sensationalist reactions to the new discovery included publications linking the new kind of rays to occult and paranormal theories, such as telepathy.[63][64]

text: Early research[edit]

text: The earliest known experimenter with X-rays was actuary William Morgan. In 1785 he presented a paper to the Royal Society of London describing the effects of passing electrical currents through a partially evacuated glass tube, the first X-ray tube.[65] This work was further extended by Humphry Davy and his assistant Michael Faraday.

text: In 1876, Eugen Goldstein proved that they came from the cathode, and named them cathode rays (Kathodenstrahlen).[66] Both William Crookes (in the 1880s)[67] and German physicist Johann Hittorf,[68] a co-inventor and early researcher of the Crookes tube, found that paper wrapped photographic plates placed near the tube became unaccountably fogged or flawed by shadows, although they had not been exposed to light. Neither found the cause nor investigated this effect.

text: In 1877 Ukrainian-born Ivan Pulyui, a lecturer in experimental physics at the University of Vienna, constructed various designs of vacuum discharge tube to investigate their properties.[69] He continued his investigations when appointed professor at the Prague Polytechnic and in 1886 he found that sealed photographic plates became dark when exposed to the emanations from the tubes. Early in 1896, just a few weeks after Röntgen published his first X-ray photograph, Pulyui published high-quality X-ray images in journals in Paris and London.[69] Although Pulyui had studied with Röntgen at the University of Strasbourg in the years 1873–75, his biographer Gaida (1997) asserts that his subsequent research was conducted independently.[69]

text: X-rays were generated and detected by Fernando Sanford (1854–1948), the foundation Professor of Physics at Stanford University, in 1891. From 1886 to 1888 he had studied in the Hermann Helmholtz laboratory in Berlin, where he became familiar with the cathode rays generated in vacuum tubes when a voltage was applied across separate electrodes, as previously studied by Heinrich Hertz and Philipp Lenard. His letter of January 6, 1893 (describing his discovery as "electric photography") to The Physical Review was duly published and an article entitled Without Lens or Light, Photographs Taken With Plate and Object in Darkness appeared in the San Francisco Examiner.[70]

text: Starting in 1888, Philipp Lenard, a student of Heinrich Hertz, conducted experiments to see whether cathode rays could pass out of the Crookes tube into the air. He built a Crookes tube (later called a "Lenard tube") with a "window" in the end made of thin aluminum, facing the cathode so the cathode rays would strike it. He found that something came through, that would expose photographic plates and cause fluorescence. He measured the penetrating power of these rays through various materials. It has been suggested that at least some of these "Lenard rays" were actually X-rays.[71]

text: Hermann von Helmholtz formulated mathematical equations for X-rays. He postulated a dispersion theory before Röntgen made his discovery and announcement. It was formed on the basis of the electromagnetic theory of light.[72] However, he did not work with actual X-rays.

text: In 1894 Nikola Tesla noticed damaged film in his lab that seemed to be associated with Crookes tube experiments and began investigating this radiant energy of "invisible" kinds.[73][74] After Röntgen identified the X-ray Tesla began making X-ray images of his own using high voltages and tubes of his own design,[75] as well as Crookes tubes.

text: Wilhelm Röntgen[edit]

text: On November 8, 1895, German physics professor Wilhelm Röntgen stumbled on X-rays while experimenting with Lenard and Crookes tubes and began studying them. He wrote an initial report "On a new kind of ray: A preliminary communication" and on December 28, 1895 submitted it to Würzburg's Physical-Medical Society journal.[76] This was the first paper written on X-rays. Röntgen referred to the radiation as "X", to indicate that it was an unknown type of radiation. The name stuck, although (over Röntgen's great objections) many of his colleagues suggested calling them Röntgen rays. They are still referred to as such in many languages, including German, Danish, Polish, Swedish, Finnish, Estonian, Russian, Japanese, Dutch, and Norwegian. Röntgen received the first Nobel Prize in Physics for his discovery.[77]

text: There are conflicting accounts of his discovery because Röntgen had his lab notes burned after his death, but this is a likely reconstruction by his biographers:[78][79] Röntgen was investigating cathode rays from a Crookes tube which he had wrapped in black cardboard so that the visible light from the tube would not interfere, using a fluorescent screen painted with barium platinocyanide. He noticed a faint green glow from the screen, about 1 meter away. Röntgen realized some invisible rays coming from the tube were passing through the cardboard to make the screen glow. He found they could also pass through books and papers on his desk. Röntgen threw himself into investigating these unknown rays systematically. Two months after his initial discovery, he published his paper.[citation needed]

text: Röntgen discovered their medical use when he made a picture of his wife's hand on a photographic plate formed due to X-rays. The photograph of his wife's hand was the first photograph of a human body part using X-rays. When she saw the picture, she said "I have seen my death."[80]

text: Advances in radiology[edit]

text: In 1895, Thomas Edison investigated materials' ability to fluoresce when exposed to X-rays, and found that calcium tungstate was the most effective substance. Around March 1896, the fluoroscope he developed became the standard for medical X-ray examinations. Nevertheless, Edison dropped X-ray research around 1903, even before the death of Clarence Madison Dally, one of his glassblowers. Dally had a habit of testing X-ray tubes on his hands, and acquired a cancer in them so tenacious that both arms were amputated in a futile attempt to save his life.

text: The first use of X-rays under clinical conditions was by John Hall-Edwards in Birmingham, England on 11 January 1896, when he radiographed a needle stuck in the hand of an associate.[81] On 14 February 1896 Hall-Edwards was also the first to use X-rays in a surgical operation.[82] In early 1896, several weeks after Röntgen's discovery, Ivan Romanovich Tarkhanov irradiated frogs and insects with X-rays, concluding that the rays "not only photograph, but also affect the living function".[83]

text: The first medical X-ray made in the United States was obtained using a discharge tube of Pulyui's design. In January 1896, on reading of Röntgen's discovery, Frank Austin of Dartmouth College tested all of the discharge tubes in the physics laboratory and found that only the Pulyui tube produced X-rays. This was a result of Pulyui's inclusion of an oblique "target" of mica, used for holding samples of fluorescent material, within the tube. On 3 February 1896 Gilman Frost, professor of medicine at the college, and his brother Edwin Frost, professor of physics, exposed the wrist of Eddie McCarthy, whom Gilman had treated some weeks earlier for a fracture, to the X-rays and collected the resulting image of the broken bone on gelatin photographic plates obtained from Howard Langill, a local photographer also interested in Röntgen's work.[22]

text: In 1901, U.S. President William McKinley was shot twice in an assassination attempt. While one bullet only grazed his sternum, another had lodged somewhere deep inside his abdomen and could not be found. "A worried McKinley aide sent word to inventor Thomas Edison to rush an X-ray machine to Buffalo to find the stray bullet. It arrived but wasn't used." While the shooting itself had not been lethal, "gangrene had developed along the path of the bullet, and McKinley died of septic shock due to bacterial infection" six days later.[84]

text: Hazards discovered[edit]

text: With the widespread experimentation with x‑rays after their discovery in 1895 by scientists, physicians, and inventors came many stories of burns, hair loss, and worse in technical journals of the time. In February 1896, Professor John Daniel and Dr. William Lofland Dudley of Vanderbilt University reported hair loss after Dr. Dudley was X-rayed. A child who had been shot in the head was brought to the Vanderbilt laboratory in 1896. Before trying to find the bullet an experiment was attempted, for which Dudley "with his characteristic devotion to science"[85][86][87] volunteered. Daniel reported that 21 days after taking a picture of Dudley's skull (with an exposure time of one hour), he noticed a bald spot 2 inches (5.1 cm) in diameter on the part of his head nearest the X-ray tube: "A plate holder with the plates towards the side of the skull was fastened and a coin placed between the skull and the head. The tube was fastened at the other side at a distance of one-half inch from the hair."[88]

text: In August 1896 Dr. HD. Hawks, a graduate of Columbia College, suffered severe hand and chest burns from an x-ray demonstration. It was reported in Electrical Review and led to many other reports of problems associated with x-rays being sent in to the publication.[89] Many experimenters including Elihu Thomson at Edison's lab, William J. Morton, and Nikola Tesla also reported burns. Elihu Thomson deliberately exposed a finger to an x-ray tube over a period of time and suffered pain, swelling, and blistering.[90] Other effects were sometimes blamed for the damage including ultraviolet rays and (according to Tesla) ozone.[91] Many physicians claimed there were no effects from x-ray exposure at all.[90] On 3 August 1905 at San Francisco, California, Elizabeth Fleischman, American woman X-ray pioneer, died from complications as a result of her work with X-rays.[92][93][94]

text: 20th century and beyond[edit]

text: The many applications of X-rays immediately generated enormous interest. Workshops began making specialized versions of Crookes tubes for generating X-rays and these first-generation cold cathode or Crookes X-ray tubes were used until about 1920.

text: Crookes tubes were unreliable. They had to contain a small quantity of gas (invariably air) as a current will not flow in such a tube if they are fully evacuated. However, as time passed, the X-rays caused the glass to absorb the gas, causing the tube to generate "harder" X-rays until it soon stopped operating. Larger and more frequently used tubes were provided with devices for restoring the air, known as "softeners". These often took the form of a small side tube which contained a small piece of mica, a mineral that traps relatively large quantities of air within its structure. A small electrical heater heated the mica, causing it to release a small amount of air, thus restoring the tube's efficiency. However, the mica had a limited life, and the restoration process was difficult to control.

text: In 1904, John Ambrose Fleming invented the thermionic diode, the first kind of vacuum tube. This used a hot cathode that caused an electric current to flow in a vacuum. This idea was quickly applied to X-ray tubes, and hence heated-cathode X-ray tubes, called "Coolidge tubes", completely replaced the troublesome cold cathode tubes by about 1920.

text: In about 1906, the physicist Charles Barkla discovered that X-rays could be scattered by gases, and that each element had a characteristic X-ray spectrum. He won the 1917 Nobel Prize in Physics for this discovery.

text: In 1912, Max von Laue, Paul Knipping, and Walter Friedrich first observed the diffraction of X-rays by crystals. This discovery, along with the early work of Paul Peter Ewald, William Henry Bragg, and William Lawrence Bragg, gave birth to the field of X-ray crystallography.

text: The Coolidge X-ray tube was invented during the following year by William D. Coolidge. It made possible the continuous emissions of X-rays. X-ray tubes similar to this are still in use in 2012.

text: The use of X-rays for medical purposes (which developed into the field of radiation therapy) was pioneered by Major John Hall-Edwards in Birmingham, England. Then in 1908, he had to have his left arm amputated because of the spread of X-ray dermatitis on his arm.[95]

text: The X-ray microscope was developed during the 1950s.

text: The Chandra X-ray Observatory, launched on July 23, 1999, has been allowing the exploration of the very violent processes in the universe which produce X-rays. Unlike visible light, which gives a relatively stable view of the universe, the X-ray universe is unstable. It features stars being torn apart by black holes, galactic collisions, and novae, and neutron stars that build up layers of plasma that then explode into space.

text: An X-ray laser device was proposed as part of the Reagan Administration's Strategic Defense Initiative in the 1980s, but the only test of the device (a sort of laser "blaster" or death ray, powered by a thermonuclear explosion) gave inconclusive results. For technical and political reasons, the overall project (including the X-ray laser) was de-funded (though was later revived by the second Bush Administration as National Missile Defense using different technologies).

text: Phase-contrast X-ray imaging refers to a variety of techniques that use phase information of a coherent x-ray beam to image soft tissues. It has become an important method for visualizing cellular and histological structures in a wide range of biological and medical studies. There are several technologies being used for x-ray phase-contrast imaging, all utilizing different principles to convert phase variations in the x-rays emerging from an object into intensity variations.[96][97] These include propagation-based phase contrast,[98] talbot interferometry,[97] refraction-enhanced imaging,[99] and x-ray interferometry.[100] These methods provide higher contrast compared to normal absorption-contrast x-ray imaging, making it possible to see smaller details. A disadvantage is that these methods require more sophisticated equipment, such as synchrotron or microfocus x-ray sources, X-ray optics, and high resolution x-ray detectors.

text: Visibility[edit]

text: While generally considered invisible to the human eye, in special circumstances X-rays can be visible. Brandes, in an experiment a short time after Röntgen's landmark 1895 paper, reported after dark adaptation and placing his eye close to an X-ray tube, seeing a faint "blue-gray" glow which seemed to originate within the eye itself.[101] Upon hearing this, Röntgen reviewed his record books and found he too had seen the effect. When placing an X-ray tube on the opposite side of a wooden door Röntgen had noted the same blue glow, seeming to emanate from the eye itself, but thought his observations to be spurious because he only saw the effect when he used one type of tube. Later he realized that the tube which had created the effect was the only one powerful enough to make the glow plainly visible and the experiment was thereafter readily repeatable. The knowledge that X-rays are actually faintly visible to the dark-adapted naked eye has largely been forgotten today; this is probably due to the desire not to repeat what would now be seen as a recklessly dangerous and potentially harmful experiment with ionizing radiation. It is not known what exact mechanism in the eye produces the visibility: it could be due to conventional detection (excitation of rhodopsin molecules in the retina), direct excitation of retinal nerve cells, or secondary detection via, for instance, X-ray induction of phosphorescence in the eyeball with conventional retinal detection of the secondarily produced visible light.

text: Though X-rays are otherwise invisible, it is possible to see the ionization of the air molecules if the intensity of the X-ray beam is high enough. The beamline from the wiggler at the ID11 at the European Synchrotron Radiation Facility is one example of such high intensity.[102]

text: Units of measure and exposure[edit]

text: The measure of X-rays ionizing ability is called the exposure:

text:
The coulomb per kilogram (C/kg) is the SI unit of ionizing radiation exposure, and it is the amount of radiation required to create one coulomb of charge of each polarity in one kilogram of matter.
The roentgen (R) is an obsolete traditional unit of exposure, which represented the amount of radiation required to create one electrostatic unit of charge of each polarity in one cubic centimeter of dry air. 1 roentgen= 2.58×10−4 C/kg.

text: However, the effect of ionizing radiation on matter (especially living tissue) is more closely related to the amount of energy deposited into them rather than the charge generated. This measure of energy absorbed is called the absorbed dose:

text:
The gray (Gy), which has units of (joules/kilogram), is the SI unit of absorbed dose, and it is the amount of radiation required to deposit one joule of energy in one kilogram of any kind of matter.
The rad is the (obsolete) corresponding traditional unit, equal to 10 millijoules of energy deposited per kilogram. 100 rad= 1 gray.

text: The equivalent dose is the measure of the biological effect of radiation on human tissue. For X-rays it is equal to the absorbed dose.

text:
The Roentgen equivalent man (rem) is the traditional unit of equivalent dose. For X-rays it is equal to the rad, or, in other words, 10 millijoules of energy deposited per kilogram. 100 rem = 1 Sv.
The sievert (Sv) is the SI unit of equivalent dose, and also of effective dose. For X-rays the "equivalent dose" is numerically equal to a Gray (Gy). 1 Sv= 1 Gy. For the "effective dose" of X-rays, it is usually not equal to the Gray (Gy).

text:
Radiation related quantities view ‧ talk ‧ edit

Quantity
Name
Symbol
Unit
Year
SI Quantity

Activity (A)
curie
Ci
3.7 × 1010 s−1
1953
3.7×1010 Bq

becquerel
Bq
s−1
1974
SI

rutherford
Rd
106 s−1
1946
1,000,000 Bq

Exposure (X)
röntgen
R
esu / 0.001293 g of air
1928
2.58 × 10−4 C/kg

Fluence (Φ)
(reciprocal area)

m−2
1962
SI

Absorbed dose (D)
erg

erg⋅g−1
1950
1.0 × 10−4 Gy

rad
rad
100 erg⋅g−1
1953
0.010 Gy

gray
Gy
J⋅kg−1
1974
SI

Dose equivalent (H)
röntgen equivalent man
rem
100 erg⋅g−1
1971
0.010 Sv

sievert
Sv
J⋅kg−1 × WR
1977
SI


document_title: Capital punishment in the Philippines

question_text: when did the death penalty start in the philippines

root

text: Capital punishment in the Philippines

text: Spanish and American periods[edit]

text: During Spanish colonial rule, the most common methods of execution were death by firing squad (especially for treason/military crimes, usually reserved for independence fighters) and garrotte (a notable case would be the Gomburza). Death by hanging was another popular method.

tag: p

text: A prominent example is the national hero, José Rizal, who was executed by firing squad on the morning of December 30, 1896, in the park that now bears his name.[1]

text: In 1926, the electric chair (Spanish: silla eléctrica; Filipino: silya eléktrika) was introduced by the United States' colonial Insular Government,[2] making the Philippines the only other country to employ this method. The last colonial-era execution took place under Governor-General Theodore Roosevelt, Jr. in February 1932. There were no executions under Manuel L. Quezon, the first President of the Commonwealth.[3]

text: The capital crimes after regaining full sovereignty in July 1946 were murder, rape and treason. However, no executions took place until April 1950,[4] when Julio Gullien was executed for attempting to assassinate President Manuel Roxas.[5] Other notable cases includes Marciál "Baby" Ama, electrocuted at the age of 16 on October 4, 1961, for murders committed while in prison for lesser charges.[6] Ama notably became the subject of the popular 1976 film, Bitayin si... Baby Ama! (Execute Baby Ama!).[7]

text: A former powerful Governor of Negros Occidental Rafael Lacson and 22 of his allies, condemned to die in August 1954 for the murder of a political opponent.[8] Ultimately, Lacson was never executed.

text: In total, 51 people were electrocuted up to 1961. Execution numbers climbed under President Ferdinand Marcos, who was ironically himself sentenced to death in 1939 for the murder of Julio Nalundasan—the political rival of his father, Mariano; the young Ferdinand was acquitted on appeal. A notorious triple execution took place in May 1972, when Jaime José, Basilio Pineda and Edgardo Aquino were electrocuted for the 1967 abduction and gang-rape of young actress Maggie dela Riva. The state ordered that the executions be broadcast on national television.[9]

text: Under the Marcos regime, drug trafficking also became punishable by death by firing squad, such as the case with Lim Seng, whose execution in December 1972 was also ordered broadcast on national television. Future President and then Chief of the Philippine Constabulary Gen. Fidel V. Ramos was present at the execution.[10]

text: The electric chair was used until 1976, when execution by firing squad eventually replaced it as the sole method of execution. Under Marcos' 20-year authoritarian rule, however, countless more people were summarily executed, tortured or simply disappeared for opposition to his rule.[neutrality is disputed]

text: After Marcos was deposed in 1986, the newly drafted 1987 Constitution prohibited the death penalty but allowed the Congress to reinstate it "hereafter" for "heinous crimes"; making the Philippines the first Asian country to abolish capital punishment.

text: Reinstatement and moratorium[edit]

text: President Fidel V. Ramos promised during his campaign that he would support the re-introduction of the death penalty in response to increasing crime rates. The new law, drafted by Ramos, restored capital punishment by defining "heinous crimes" as everything from murder to stealing a car. This law provided the use of the electric chair until gas inhalation (chosen by the government to replace electrocution) could be used.

text: Executions resumed in 1999, starting with Leo Echegaray, who was put to death by lethal injection under Ramos' successor, Joseph Estrada, marking the first execution after the reinstatement of the death penalty. The next execution saw an embarrassing mishap when President Estrada decided to grant a last-minute reprieve, but failed to get through to the prison authorities in time to stop the execution. Following on a personal appeal by his spiritual advisor, Bishop Teodoro Bacani, Estrada called a moratorium in 2000 to honor the bimillenial anniversary of Christ's birth.[11] Executions were resumed a year later.

text: Estrada's successor, Gloria Macapagal Arroyo, was a vocal opponent of the death penalty and also approved a moratorium, but later permitted executions and denied pardons.[citation needed]

text: When the Philippines had the death penalty, male inmates condemned to death were held at New Bilibid Prison and female inmates condemned to death were held at Correctional Institution for Women (Mandaluyong).[12] The death chamber for inmates to be electrocuted was in Building 14, within the Maximum Security Compound of New Bilibid. The Bureau of Corrections (BuCor) Museum previously served as the lethal injection chamber.[13]

text: Second suspension[edit]

text: On 15 April 2006, the sentences of 1,230 death row inmates were commuted to life imprisonment, in what Amnesty International believes to be the "largest ever commutation of death sentences".[14]

text: Capital punishment was again suspended via Republic Act No. 9346, which was signed by President Gloria Macapagal-Arroyo on 24 June 2006. The bill followed a vote held in Congress earlier that month which overwhelmingly supported the abolition of the practice.[15] The penalties of life imprisonment and reclusion perpetua (detention of indefinite length, usually for at least 30 years) replaced the death penalty.[16] Critics of Arroyo's initiative called it a political move meant to placate the Roman Catholic Church, some sectors of which were increasingly vocal in their opposition to her rule.

text: Protocol to the International Covenant on Civil and Political Rights[edit]

text: The Philippines subsequently signed the Second Optional Protocol to the International Covenant on Civil and Political Rights. The Optional Protocol commits its members to the abolition of the death penalty within their borders.

text: It was signed on 20 Sep 2006 and ratified on 20 Nov 2007.[17]

text: On December 6, 2016, after the justice committee of the Philippine House of Representatives approved a draft measure on the reimposition of the death, Zeid Ra’ad Al Hussein, the UN Commissioner for Human Rights released an open letter addressed to the Philippine Speaker of the House and the President of the Senate saying, "International law does not permit a State that has ratified or acceded to the Second Optional Protocol to denounce it or withdraw from it”. Zaid asserted that because there is no “denunciation clause” in the protocol “thereby guaranteeing the permanent non-reintroduction of the death penalty by States that ratified the Protocol.”.[18]

text: Aftermath[edit]

text: President Arroyo controversially pardoned many prisoners during her presidency, including a 2009 pardon for all remaining felons convicted for the 1983 assassination of former Senator and opposition leader Benigno Aquino, Jr.[19]

text: Support for reintroduction of capital punishment[edit]

text: During the 2016 election, presidential candidate and frontrunner, Davao City mayor Rodrigo Duterte, campaigned to restore the death penalty in the Philippines.[20][21][22] During the "Yes or No" segment of the second presidential debate on March 20, 2016, Duterte and Senator Grace Poe were the only candidates who said "Yes" when asked about the restoration of the death penalty in the country, favoring the decision.[23] Duterte, who won the election in May 2016, supports restoration of the death penalty by hanging.[24] It has been reported that he wants capital punishment for criminals involved in illegal drugs, gun-for-hire syndicates and those who commit "heinous crimes" such as rape, robbery or car theft where the victim is murdered,[24] while Poe has stated that the capital punishment should apply to criminals convicted of "drugs and multiple crimes where involved people can no longer be rehabilitated."[25] Duterte has theatrically vowed "to litter Manila Bay with the bodies of criminals."[26] In December 2016, the bill to resume capital punishment for certain "heinous offenses" swiftly passed out of Committee in the House of Representatives; it passed the full House of Representatives in February 2017.[27] As of March 2017[update], passage of the law awaits the Senate's approval.[27] However, the majority of Filipino senators have already expressed their disapproval of the death penalty, effectively blocking its reenactment.[citation needed]

text: Methods[edit]

text: The Philippines was the only country aside from the United States that used the electric chair, due to its being introduced during the US colonial period. Until its first abolition in 1987, the country reverted to using death by firing squad.

text: After re-introduction of the death penalty in 1993, the country switched to lethal injection as its sole method of execution.


document_title: Neural tube defect

question_text: when can a neural tube defect be detected

text: Neural tube defect

text: Types[edit]

text: There are two types of NTDs: open, which are more common, and closed. Open NTDs occur when the brain and/or spinal cord are exposed at birth through a defect in the skull or vertebrae (back bones). Examples of open NTDs are anencephaly, encephaloceles, hydranencephaly, iniencephaly, schizencephaly, and spina bifida. Rarer types of NTDs are called closed NTDs. Closed NTDs occur when the spinal defect is covered by skin. Common examples of closed NTDs are lipomyelomeningocele, lipomeningocele, and tethered cord.

text: Anencephaly[edit]

text: Anencephaly (without brain) is a neural tube defect that occurs when the head end of the neural tube fails to close, usually during the 23rd and 26th days of pregnancy, resulting in an absence of a major portion of the brain and skull. Infants born with this condition are born without the main part of the forebrain—the largest part of the cerebrum—and are usually blind, deaf and unconscious. The lack of a functioning cerebrum will ensure that the infant will never gain consciousness. Infants are either stillborn or usually die within a few hours or days after birth.

text: Encephaloceles[edit]

text: Encephaloceles are characterized by protrusions of the brain through the skull that are sac-like and covered with membrane. They can be a groove down the middle of the upper part of the skull, between the forehead and nose, or the back of the skull. Encephaloceles are often obvious and diagnosed immediately. Sometimes small encephaloceles in the nasal and forehead are undetected. [6]

text: Hydranencephaly[edit]

text: Hydranencephaly is a condition in which the cerebral hemispheres are missing and instead filled with sacs of cerebrospinal fluid.

text: Iniencephaly[edit]

text: Iniencephaly is a rare neural tube defect that results in extreme bending of the head to the spine. The diagnosis can usually be made on antenatal ultrasound scanning, but if not will undoubtedly be made immediately after birth because the head is bent backwards and the face looks upwards. Usually the neck is absent. The skin of the face connects directly to the chest and the scalp connects to the upper back. The infant will usually not survive more than a few hours.

text: Spina bifida[edit]

text: Spina bifida is further divided into two subclasses, spina bifida cystica and spina bifida occulta.

text: Spina bifida cystica[edit]

text: This includes meningocele and myelomeningocele. Meningocele is less severe and is characterized by herniation of the meninges, but not the spinal cord, through the opening in the spinal canal. Myelomeningocele involves herniation of the meninges as well as the spinal cord through the opening.[7]

text: Spina bifida occulta[edit]

text: In this type of neural tube defect, the meninges do not herniate through the opening in the spinal canal.[7] It is a common condition, occurring in 10–20% of otherwise healthy people[citation needed]. By definition, spina bifida occulta means hidden split spine.[8] The most frequently seen form of spina bifida occulta is when parts of the bones of the spine, called the spinous process, and the neural arch appear abnormal on a radiogram, and is generally harmless. Usually the spinal cord and spinal nerves are not involved.[9] The risk of recurrence in those who have a first degree relative (e.g. parent, sibling) is 5–10 times greater than that in the general population. The genetic risk of recurrence with symptomatic forms of spina bifida occulta is uncertain.

text: Cause[edit]

text: Folate deficiency[edit]

text: Folate (vitamin B9) and vitamin B12 are very important in reducing the occurrences of NTDs.[10] Folate is required for the production and maintenance of new cells, for DNA synthesis and RNA synthesis. Folate is needed to carry one carbon groups for methylation and nucleic acid synthesis. It has been hypothesized that the early human embryo may be particularly vulnerable to folate deficiency due to differences of the functional enzymes in this pathway during embryogenesis combined with high demand for post translational methylations of the cytoskeleton in neural cells during neural tube closure.[11] Failure of post-translational methylation of the cytoskeleton, required for differentiation has been implicated in neural tube defects.[12] Vitamin B12 is also an important receptor in the folate biopathway such that studies have shown deficiency in vitamin B12 contributes to risk of NTDs as well.[13] Importantly, a deficiency of folate itself does not cause neural tube defects. The association seen between reduced neural tube defects and folic acid supplementation is due to a gene-environment interaction such as vulnerability caused by the C677T Methylenetetrahydrofolate reductase (MTHFR) variant. Supplementing folic acid during pregnancy reduces the prevalence of NTDs by not exposing this otherwise sub-clinical mutation to aggravating conditions.[14] There is substantial evidence that direct folic supplementation increases blood serum levels of bioavailable folate even though at least one study have shown slow and variable activity of dihydrofolate reductase in human liver.[15][16] A diet rich in natural folate (350 μg/d) can show as much increase in plasma folate as taking low levels of folic acid (250 μg/d) in individuals[17] However a comparison of general population outcomes across many countries with different approaches to increasing folate consumption has found that only general food fortification with folic acid reduces neural tube defects [18] While there have been concerns about folic acid supplementation being linked to an increased risk for cancer, a systematic review in 2012 shows there is no evidence except in the case of prostate cancer which indicates a modest reduction in risk.[19]

text: Gene-environment interaction[edit]

text: Other potential causes can include folate antimetabolites (such as methotrexate), maternal diabetes, maternal obesity, mycotoxins in contaminated corn meal, arsenic, hyperthermia in early development, and radiation.[20][21][22] Studies have shown that both maternal cigarette smoking and maternal exposure to secondhand smoke increased the risk for neural tube defects in offspring.[23] A mechanism by which maternal exposure to cigarette smoke could increase NTD risk in offspring is suggested by several studies that show an association between cigarette smoking and elevations of homocysteine levels. The study suggests that cigarette smoke, including secondhand exposure, is not only hazardous to the mother, but may also interfere with neural tube closure in the developing embryo.[24] All of the above may act by interference with some aspect of normal folic acid metabolism and folate linked methylation related cellular processes as there are multiple genes of this type associated with neural tube defects.[25]

text: Other[edit]

text: Folic acid supplementation reduces the prevalence of neural tube defects by approximately 70% of neural tube defects indicating that 30% are not folate-dependent and are due to some cause other than alterations of methylation patterns.[26] Multiple other genes related to neural tube defects exist which are candidates for folate insensitive neural tube defects.[25] There are also several syndromes such as Meckel syndrome, and Triploid Syndrome which are frequently accompanied by neural tube defects that are assumed to be unrelated to folate metabolism[27]

text: Diagnosis[edit]

text: Tests for neural tube defects include ultrasound examination and measurement of maternal serum alpha-fetoprotein (MSAFP). Amniotic fluid alpha-fetoprotein (AFAFP) and amniotic fluid acetylcholinesterase (AFAChE) tests are also used to confirming if ultrasound screening indicates a positive risk.[28] Often, these defects are apparent at birth, but acute defects may not be diagnosed until much later in life. An elevated MSAFP measured at 16–18 weeks gestation is a good predictor of open neural tube defects, however the test has a very high false positive rate, (2% of all women tested in Ontario, Canada between 1993 and 2000 tested positive without having an open neural tube defect, although 5% is the commonly quoted result worldwide) and only a portion of neural tube defects are detected by this screen test (73% in the same Ontario study).[29] MSAFP screening combined with routine ultrasonography has the best detection rate although detection by ultrasonography is dependent on operator training and the quality of the equipment.[30][31]

text: Prevention[edit]

text: In 1996, the United States Food and Drug Administration published regulations requiring the addition of folic acid to enriched breads, cereals, flour and other grain products.[32] It is important to note that during the first four weeks of pregnancy (when most women do not even realize that they are pregnant), adequate folate intake is essential for proper operation of the neurulation process. Therefore, women who could become pregnant are advised to eat foods fortified with folic acid or take supplements in addition to eating folate-rich foods to reduce the risks of serious birth defects.[33][34][35] In Canada, mandatory fortification of selected foods with folic acid has been shown to reduce the incidence of neural tube defects by 46%.[36]

text: Women who may become pregnant are advised to get 400 micrograms of folic acid daily. Women who have previously given birth to a child with a neural tube defect may benefit from a supplement containing 4.0 mg/5.0 mg in the UK mg daily, following advice provided by their doctor.[37]

text: Treatment[edit]

text: Treatments of NTDs depends on the severity of the complication. No treatment is available for anencephaly and infants usually do not survive more than a few hours. Aggressive surgical management has improved survival and the functions of infants with spina bifida, meningoceles and mild myelomeningoceles. The success of surgery often depends on the amount of brain tissue involved in the encephalocele. The goal of treatment for NTDs is to allow the individual to achieve the highest level of function and independence. Fetal surgery in utero before 26 weeks gestation has been performed with some hope that there is benefit to the final outcome including a reduction in Arnold–Chiari malformation and thereby decreases the need for a ventriculoperitoneal shunt but the procedure is very high risk for both mother and baby and is considered extremely invasive with questions that the positive outcomes may be due to ascertainment bias and not true benefit. Further, this surgery is not a cure for all problems associated with a neural tube defect. Other areas of research include tissue engineering and stem cell therapy but this research has not been used in humans.[38]

text: Epidemiology[edit]

text: Neural tube defects resulted in 71,000 deaths globally in 2010.[39]


document_title: Snickers

question_text: where did the snickers bar get its name

question_tokens: where did the snickers bar get its name

text: Snickers

text: History[edit]

text: In 1930,[1] Mars introduced Snickers, named after the favorite horse of the Mars family.[6] The Snickers chocolate bar consists of nougat, peanuts, and caramel with a chocolate coating. The bar was marketed under the name "Marathon" in the UK and Ireland until July 19, 1990, when Mars decided to align the UK product with the global Snickers name (Mars had marketed and discontinued an unrelated bar named Marathon in the United States during the 1970s). There are also several other Snickers products such as Snickers mini, dark chocolate, ice cream bars, Snickers with almonds, Snickers with hazelnuts, Snickers peanut butter bars, Snickers protein and Snickers with Extra Caramel.[7]

text: Snickers Duo[edit]

text: A replacement for the king size Snickers bar was launched in the UK in 2004 and designed to conform to the September 2004 Food and Drink Federation (FDF) "Manifesto for Food and Health". Part of the FDF manifesto was seven pledges of action to encourage the food and drink industry to be more health conscious.[8] Reducing portion size, clearer food labels, and reduction of the levels of fat, sugar, and salt were among the FDF pledges. Mars Incorporated pledged to phase out their king-size bars in 2005 and replace them with shareable bars. A Mars spokesman said: "Our king-size bars that come in one portion will be changed so they are shareable or can be consumed on more than one occasion. The name king-size will be phased out."[8]

text: These were eventually replaced by the 'Duo', a double bar pack. Though this change to Duos reduced the weight from 3.5 to 3.29 ounces (99 to 93 g), the price remained the same. The packaging has step-by-step picture instructions of how to open a Duo into two bars, in four simple actions.[9] As Mars stated fulfillment of their promise, the Duo format was met with criticism by the National Obesity Forum and National Consumer Council.[10]

text: Australian recall[edit]

text: In December 2000, tens of thousands of Snickers and Mars Bars were removed from New South Wales store shelves due to a series of threatening letters which resulted in fears that the chocolate bars had been poisoned.[11] Mars received letters from an unidentified individual indicating that they planned to plant poisoned chocolate bars on store shelves.[11] The last letter sent included a Snickers bar contaminated with a substance which was later identified as rat poison.[11] The letters claimed that there were seven additional chocolate bars which had been tampered with and which were for sale to the public.[11] As a precautionary measure, Mars issued a massive recall.[11] Mars said that there had been no demand for money and complaints directed to an unidentified third party.[11]

text: Caloric value[edit]

text: The USDA lists the caloric value of a 2-ounce (57 gram) Snickers bar as 280 kilocalories (1,200 kJ).[12] As of 2018, the United Kingdom bar has a weight of 48g, with 245 kcal,[13] and the Canadian bar 52g with 250 kcal.[citation needed]

text: Bar weight[edit]

text: Over the years, the bar weight has decreased: Before 2009, in the UK a single Snickers bar had a weight of 62.5g. This weight was subsequently reduced to 58g in 2009,[14] and to 48g in 2013.[15]

text: Products containing Snickers[edit]

text: Containing approximately 450 calories (1,900 J) per bar,[16] deep fried chocolate bars (including Snickers and Mars bars) became a specialty in fish and chips shops in Scotland in 1995,[17] and in the early 2000s, became popular at American state fairs.

text: In 2012, the British Food Commission highlighted celebrity chef Antony Worrall Thompson's "Snickers pie",[18] which contained five Snickers bars among other ingredients, suggesting it was one of the unhealthiest desserts ever; one slice providing "over 1,250 calories (5,200 kJ) from sugar and fat alone", more than half a day's requirement for an average adult. The pie had featured on his BBC Saturday programme some two years earlier and the chef described it as an occasional treat only.[19]

text: Advertising[edit]

text: It's So Satisfying[edit]

text: In 1980, Snickers ran ads which featured a variety of everyday people discussing why they like Snickers. The ads featured a jingle that said "It's so satisfying" and had the classic hand that would open and close showing a handful of peanuts converting to a Snickers bar. "Packed with peanuts, Snickers really satisfies" was shown in the commercials.

text: 1984 Olympics[edit]

text: Mars paid $5 million to have Snickers and M&M's named the "official snack" of the 1984 Summer Olympics, outraging nutritionists.[20] Sports promotions in international games continued to be a prominent marketing tool for Mars, that would keep Snickers as an international brand while also selling local bars in some markets.[21]

text: Not Going Anywhere For a While? (Hungry? Grab a Snickers!/Why Wait?)[edit]

text: Beginning in 1995, Snickers ran ads which featured someone making a self-inflicted mistake, with the voice-over saying "Not going anywhere for a while? Grab a Snickers!" The tag line at the end of each ad proclaimed, "Hungry? Why Wait?"

text: One such ad had a player for a fictional American football team showing off his new tattoo of the team's logo on his back to his teammates. He then shows it to his head coach who, after complimenting the tattoo, immediately tells him that he's been traded to Miami. The player then goes to have his old team's logo replaced with the new team's logo.[citation needed]

text: Some of the ads were done in conjunction with the National Football League, with whom Snickers had a sponsorship deal at the time. One ad featured a member of the grounds crew at Arrowhead Stadium painting the field for an upcoming Kansas City Chiefs game in hot, late-summer weather. After finishing one of the end zones, and visibly exhausted, one of the Chiefs players walks up to him and says the field looks great, "but who are the Chefs?", showing that despite all the hard work the painter accidentally omitted the "i" in Chiefs.[22] Another had Marv Levy in the Buffalo Bills locker room lecturing his team that "no one's going anywhere" until the Bills figure out how to actually win a Super Bowl.[23]

text: Snickers Feast[edit]

text: In 2007, Snickers launched a campaign which featured Henry the VIII and a Viking among others who attend the "Snickers Feast". It consisted of various commercials of the gang and their adventures on the feast.[citation needed]

text: Super Bowl XLI commercial[edit]

text: On February 4, 2007, during Super Bowl XLI, Snickers commercials aired which resulted in complaints by gay and lesbian groups against the maker of the candy bar, Masterfoods USA of Hackettstown, New Jersey, a division of Mars, Incorporated. The commercial showed a pair of auto mechanics accidentally touching lips while sharing a Snickers bar. After quickly pulling away, one mechanic says, "I think we just accidentally kissed.", and another mechanic exclaims, "Quick! Do something manly!" and in three of the four versions, they do so mostly in the form of injury, including tearing out chest hair, striking each other with a very large pipe wrench, and drinking motor oil and windshield washer fluid. In the fourth version, however, a third mechanic shows up and asks "Is there room for three in this Love Boat?"

text: Complaints were lodged against Masterfoods that the ads were homophobic. Human Rights Campaign president Joe Solmonese is quoted as saying

text: "This type of jeering from professional sports figures at the sight of two men kissing fuels the kind of anti-gay bullying that haunts countless gay and lesbian school children on playgrounds all across the country."[24]

text: Gay and Lesbian Alliance Against Defamation (GLAAD) president Neil Giuliano said "That Snickers, Mars and the NFL would promote and endorse this kind of prejudice is simply inexcusable." Masterfoods has since pulled the ads and the website.[24][25][26]

text: Mr. T[edit]

text: In 2006, Mr. T starred in a Snickers advert in the UK where he rides up in an army tank and shouts abuse at a football player who appears to be faking an injury, threatening to introduce him to his friend Pain. Another advert featured Mr. T launching bars at a swimmer who appeared to refuse to get in a swimming pool because of the cold temperature of the water. In 2008, a European Snickers commercial in which Mr. T uses a Jeep-mounted Minigun to fire Snickers bars at a speedwalker for being a "disgrace to the man race" was pulled after complaints from a US pressure group that the advertisement was homophobic.[27] These adverts usually ended with Mr. T saying "Snickers: Get Some Nuts!"

text: NASCAR[edit]

text: In NASCAR racing, Snickers (and the rest of the Mars affiliated brands) sponsor Kyle Busch's #18 Toyota for Joe Gibbs Racing. Prior to that the brand served as a primary sponsor for Ricky Rudd's #88 Robert Yates Racing Ford as well as an associate sponsor for the team's #38 car driven first by Elliott Sadler and then by David Gilliland, and an associate sponsor for the MB2 Motorsports #36 Pontiac driven by Derrike Cope, Ernie Irvan, Ken Schrader, and others. In 1990, Bobby Hillin drove for Stavola Brothers Racing in the #8 Snickers Buick, marking the candy's first appearance as a sponsor; it had since been driven by Rick Wilson and Dick Trickle.

text: FIFA World Cup & UEFA Euro Sponsorship[edit]

text: Snickers was the Official Sponsor of the FIFA World Cup from 1990 until 1998 editions and the UEFA European Championship from 1996 until 2000.

text: You're Not You When You're Hungry[edit]

text: In 2010, a new advertising campaign was launched, based around people turning into different people (usually celebrities) when they're hungry (taking the new campaign's name "You're Not You When You're Hungry" quite literally). In 2010, Betty White and Abe Vigoda appeared in the first Snickers commercial in this campaign, playing American football. The commercial was ranked by ADBOWL as the best advertisement of the year. This commercial was also briefly spoofed in an episode of SportsNation on ESPN2 with Michelle Beadle playing the role instead of Betty White in 2011.[28] Later that year, Snickers commercials featured singers Aretha Franklin and Liza Minnelli, and comedians Richard Lewis and Roseanne Barr. A 2011 commercial featured actors Joe Pesci and Don Rickles.

text: The tagline varied depending on the commercial's location or what variety the commercial is showing. The UK version (featuring men in a changing room turning into Joan Collins and Stephanie Beacham as a result of hunger) retains Mr. T's slogan. In Latin America, the slogan was the same as in the UK version, except that men doing extreme sports turning into the Mexican singer Anahí as a result of hunger.[29]

text: In 2013, Robin Williams and Bobcat Goldthwait also appeared in a Snickers football commercial. In March 2014, a commercial featuring Godzilla was released to promote the 2014 Godzilla film. In the commercial, Godzilla is shown hanging out with humans on the beach, riding dirt bikes, and water skiing; he only begins rampaging once he's hungry. After being fed a Snickers bar, he resumes having fun with the humans.[30]

text: In October 2014, Rowan Atkinson as Mr. Bean returned on television by appearing on several UK Snickers commercials and cinema spots.[31]

text: In February 2015, Snickers' Super Bowl XLIX commercial featured a parody of a scene from an episode of The Brady Bunch entitled "Subject Was Noses." In the commercial, Carol and Mike try to calm down a hungry and angry Danny Trejo. When the parents give Trejo a Snickers bar, he reverts into Marcia before an irate Jan (played by Steve Buscemi) rants upstairs and walks away.[32]

text: In 2016, for Super Bowl 50, another Snickers commercial was made, featuring Willem Dafoe (as Marilyn Monroe) and Eugene Levy, where "Marilyn" complains about filming the iconic "subway grate" scene in The Seven Year Itch. After being given a Snickers, Marilyn goes ahead with the scene, with Levy operating the fan below, commenting that the scene won't make the movie's final cut, that nobody would want to see it.

text: WrestleMania[edit]

text: Snickers has been an official sponsor of WWE's WrestleMania events, including WrestleMania 2000, 22, 32, 33 and 34, while its Cruncher variant sponsored WrestleMania X-Seven, XIX, XX and 21. Since then, Snickers has sponsored superstars such as Enzo Amore and Big Cass with their signature term, SAWFT, which is labelled at the back of the chocolate bar.


document_title: Zoology

question_text: name the branch of zoology that deals with the scientific study of animal behaviour

text: Zoology

text: History[edit]

text: Ancient history to Darwin[edit]

text: The history of zoology traces the study of the animal kingdom from ancient to modern times. Although the concept of zoology as a single coherent field arose much later, the zoological sciences emerged from natural history reaching back to the biological works of Aristotle and Galen in the ancient Greco-Roman world. This ancient work was further developed in the Middle Ages by Muslim physicians and scholars such as Albertus Magnus.[2][3][4] During the Renaissance and early modern period, zoological thought was revolutionized in Europe by a renewed interest in empiricism and the discovery of many novel organisms. Prominent in this movement were Vesalius and William Harvey, who used experimentation and careful observation in physiology, and naturalists such as Carl Linnaeus, Jean-Baptiste Lamarck, and Buffon who began to classify the diversity of life and the fossil record, as well as the development and behavior of organisms. Microscopy revealed the previously unknown world of microorganisms, laying the groundwork for cell theory.[5]  The growing importance of natural theology, partly a response to the rise of mechanical philosophy, encouraged the growth of natural history (although it entrenched the argument from design).

text: Over the 18th, 19th, and 20th centuries, zoology became an increasingly professional scientific discipline. Explorer-naturalists such as Alexander von Humboldt investigated the interaction between organisms and their environment, and the ways this relationship depends on geography, laying the foundations for biogeography, ecology and ethology. Naturalists began to reject essentialism and consider the importance of extinction and the mutability of species. Cell theory provided a new perspective on the fundamental basis of life.[6][7]

text: Post-Darwin[edit]

text: These developments, as well as the results from embryology and paleontology, were synthesized in Charles Darwin's theory of evolution by natural selection. In 1859, Darwin placed the theory of organic evolution on a new footing, by his discovery of a process by which organic evolution can occur, and provided observational evidence that it had done so.[8]

text: Darwin gave a new direction to morphology and physiology, by uniting them in a common biological theory: the theory of organic evolution. The result was a reconstruction of the classification of animals upon a genealogical basis, fresh investigation of the development of animals, and early attempts to determine their genetic relationships. The end of the 19th century saw the fall of spontaneous generation and the rise of the germ theory of disease, though the mechanism of inheritance remained a mystery. In the early 20th century, the rediscovery of Mendel's work led to the rapid development of genetics, and by the 1930s the combination of population genetics and natural selection in the modern synthesis created evolutionary biology.[9]

text: Research[edit]

text: Structural[edit]

text: Cell biology studies the structural and physiological properties of cells, including their behavior, interactions, and environment. This is done on both the microscopic and molecular levels, for single-celled organisms such as bacteria as well as the specialized cells in multicellular organisms such as humans.  Understanding the structure and function of cells is fundamental to all of the biological sciences. The similarities and differences between cell types are particularly relevant to molecular biology.

text: Anatomy considers the forms of macroscopic structures such as organs and organ systems.[10] It focuses on how organs and organ systems work together in the bodies of humans and animals, in addition to how they work independently. Anatomy and cell biology are two studies that are closely related, and can be categorized under "structural" studies.

text: Physiological[edit]

text: Physiology studies the mechanical, physical, and biochemical processes of living organisms by attempting to understand how all of the structures function as a whole. The theme of "structure to function" is central to biology. Physiological studies have traditionally been divided into plant physiology and animal physiology, but some principles of physiology are universal, no matter what particular organism is being studied. For example, what is learned about the physiology of yeast cells can also apply to human cells. The field of animal physiology extends the tools and methods of human physiology to non-human species. Physiology studies how for example nervous, immune, endocrine, respiratory, and circulatory systems, function and interact.

text: Evolutionary[edit]

text: Evolutionary research is concerned with the origin and descent of species, as well as their change over time, and includes scientists from many taxonomically oriented disciplines. For example, it generally involves scientists who have special training in particular organisms such as mammalogy, ornithology, herpetology, or entomology, but use those organisms as systems to answer general questions about evolution.

text: Evolutionary biology is partly based on paleontology, which uses the fossil record to answer questions about the mode and tempo of evolution,[11] and partly on the developments in areas such as population genetics[12] and evolutionary theory. Following the development of DNA fingerprinting techniques in the late 20th century, the application of these techniques in zoology has increased the understanding of animal populations.[13]  In the 1980s, developmental biology re-entered evolutionary biology from its initial exclusion from the modern synthesis through the study of evolutionary developmental biology.[14] Related fields often considered part of evolutionary biology are phylogenetics, systematics, and taxonomy.

text: Classification[edit]

text: Scientific classification in zoology, is a method by which zoologists group and categorize organisms by biological type, such as genus or species. Biological classification is a form of scientific taxonomy. Modern biological classification has its root in the work of Carl Linnaeus, who grouped species according to shared physical characteristics. These groupings have since been revised to improve consistency with the Darwinian principle of common descent. Molecular phylogenetics, which uses DNA sequences as data, has driven many recent revisions and is likely to continue to do so. Biological classification belongs to the science of zoological systematics.

text: Many scientists now consider the five-kingdom system outdated. Modern alternative classification systems generally start with the three-domain system: Archaea (originally Archaebacteria); Bacteria (originally Eubacteria); Eukaryota (including protists, fungi, plants, and animals)[15]  These domains reflect whether the cells have nuclei or not, as well as differences in the chemical composition of the cell exteriors.[15]

text:
Further, each kingdom is broken down recursively until each species is separately classified. The order is:
Domain; kingdom; phylum; class; order; family; genus; species. The scientific name of an organism is generated from its genus and species. For example, humans are listed as Homo sapiens. Homo is the genus, and sapiens the specific epithet, both of them combined make up the species name. When writing the scientific name of an organism, it is proper to capitalize the first letter in the genus and put all of the specific epithet in lowercase. Additionally, the entire term may be italicized or underlined.[16]

text: The dominant classification system is called the Linnaean taxonomy. It includes ranks and binomial nomenclature. The classification, taxonomy, and nomenclature of zoological organisms is administered by the International Code of Zoological Nomenclature. A merging draft, BioCode, was published in 1997 in an attempt to standardize nomenclature, but has yet to be formally adopted.[17]

text: Ethology[edit]

text: Ethology is the scientific and objective study of animal behavior under natural conditions,[18]  as opposed to behaviourism, which focuses on behavioral response studies in a laboratory setting.  Ethologists have been particularly concerned with the evolution of behavior and the understanding of behavior in terms of the theory of natural selection. In one sense, the first modern ethologist was Charles Darwin, whose book, The Expression of the Emotions in Man and Animals, influenced many future ethologists.[19]

text: Biogeography[edit]

text: Biogeography studies the spatial distribution of organisms on the Earth,[20] focusing on topics like plate tectonics, climate change, dispersal and migration, and cladistics. The creation of this study is widely accredited to Alfred Russel Wallace, a British biologist who had some of his work jointly published with Charles Darwin.

text: Branches of zoology[edit]

text: Although the study of animal life is ancient, its scientific incarnation is relatively modern. This mirrors the transition from natural history to biology at the start of the 19th century. Since Hunter and Cuvier, comparative anatomical study has been associated with morphography, shaping the modern areas of zoological investigation:  anatomy, physiology, histology, embryology, teratology and ethology.[21] Modern zoology first arose in German and British universities. In Britain, Thomas Henry Huxley was a prominent figure. His ideas were centered on the morphology of animals. Many consider him the greatest comparative anatomist of the latter half of the 19th century. Similar to Hunter, his courses were composed of lectures and laboratory practical classes in contrast to the previous format of lectures only.

text: Gradually zoology expanded beyond Huxley's comparative anatomy to include the following sub-disciplines:

text:
Zoography, also known as descriptive zoology, is the applied science of describing animals and their habitats
Comparative anatomy studies the structure of animals
Animal physiology
Behavioral ecology
Ethology studies animal behavior
Invertebrate zoology
Vertebrate zoology
Soil zoology
The various taxonomically oriented disciplines such as mammalogy, biological anthropology, herpetology, ornithology, and entomology identify and classify species and study the structures and mechanisms specific to those groups.

tag: ul

text: Related fields:

text:
Evolutionary biology: Development of both animals and plants is considered in the articles on evolution, population genetics, heredity, variation, Mendelism, and reproduction.
Molecular biology studies the common genetic and developmental mechanisms of animals and plants
Palaeontology
Systematics, cladistics, phylogenetics, phylogeography, biogeography, and taxonomy classify and group species via common descent and regional associations.