|
Joseph Edwin Barnard
Joseph Edwin Barnard (7 December 1868/70 – 25 October 1949) was a British microscopist and businessman known for his refinements to the ultraviolet microscope and for taking early photomicrographs of viruses, including ectromelia virus, foot-and-mouth disease virus and vesicular stomatitis virus. In a widely publicised paper of 1925 he published images of supposed viruses isolated from various avian and mammalian tumours, but the results could not be replicated by others and he did not publish on the topic again. He headed the department of applied optics at the National Institute for Medical Research on an honorary part-time basis, while carrying out his business as a hatter, from 1920 until his retirement during the Second World War. He was an elected fellow of the Institute of Physics (1923) and the Royal Society (1924), and an honorary member of the Royal Microscopical Society (1948), of which he was president three times. His ''Practical Photo-micrography'' (1911) was a standar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microscopist
Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical, electron, and scanning probe microscopy, along with the emerging field of X-ray microscopy. Optical microscopy and electron microscopy involve the diffraction, reflection, or refraction of electromagnetic radiation/electron beams interacting with the specimen, and the collection of the scattered radiation or another signal in order to create an image. This process may be carried out by wide-field irradiation of the sample (for example standard light microscopy and transmission electron microscopy) or by scanning a fine beam over the sample (for example confocal laser scanning microscopy and scanning electron microscopy). Scanning probe microscopy involves the interaction of a scanning probe with the surface of the object of interest. The de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hampstead
Hampstead () is an area in London, England, which lies northwest of Charing Cross, located mainly in the London Borough of Camden, with a small part in the London Borough of Barnet. It borders Highgate and Golders Green to the north, Belsize Park to the south and is surrounded from the northeast by Hampstead Heath, a large, hilly expanse of parkland. Hampstead is known for its intellectual, artistic, liberal, and literary associations. It contains a number of listed buildings, such as Burgh House, Kenwood House, the Spaniard's Inn, and the Everyman cinema. With some of the most expensive housing in London, Hampstead has had many notable residents, both past and present, including King Constantine II of Greece and his wife Queen Anne Marie, Helena Bonham Carter, Agatha Christie, T. S. Eliot, Jon English, Sigmund Freud, Stephen Fry, Ricky Gervais, Jim Henson, George Orwell, Harry Styles and Elizabeth Taylor. As of 2004, Hampstead has been home to more Prime Mini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endotoxin
Lipopolysaccharide (LPS), now more commonly known as endotoxin, is a collective term for components of the outermost membrane of the cell envelope of gram-negative bacteria, such as '' E. coli'' and ''Salmonella'' with a common structural architecture. Lipopolysaccharides are large molecules consisting of three parts: an outer core polysaccharide termed the O-antigen, an inner core oligosaccharide and Lipid A (from which toxicity is largely derived), all covalently linked. In current terminology, the term endotoxin is often used synonymously with LPS, although there are a few endotoxins (in the original sense of toxins that are inside the bacterial cell that are released when the cell disintegrates) that are not related to LPS, such as the so-called delta endotoxin proteins produced by '' Bacillus thuringiensis''. Lipopolysaccharides can have substantial impacts on human health, primarily through interactions with the immune system. LPS is a potent activator of the immune sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryotic Cell
The eukaryotes ( ) constitute the domain of Eukaryota or Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of Outline of life forms, life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal Kingdom (biology), kingdom Asgard (Archaea), Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as Flagellated cell, flagellated cells. The leading evolutionary theory is they were created by symbiogenesis betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Alexander Murray (FRS)
James Alexander Murray (9 November 1864 in Moncton, New Brunswick – 16 February 1960) was a Conservative politician and the 16th premier of New Brunswick. Murray was first elected to the legislature in 1908 and served as Minister of Agriculture An agriculture ministry (also called an agriculture department, agriculture board, agriculture council, or agriculture agency, or ministry of rural development) is a ministry charged with agriculture. The ministry is often headed by a minister f ... before becoming Premier in 1917 only to have his government defeated in the general election weeks later. External linksGovernment of New Brunswick biography {{DEFAULTSORT:Murray, James Alexander 1864 births 1960 deaths Leaders of the Progressive Conservative Party of New Brunswick Politicians from Moncton Premiers of New Brunswick 20th-century members of the Legislative Assembly of New Brunswick ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Objective (optics)
In optical engineering, an objective is an optical element that gathers light from an object being observed and Focus (optics), focuses the ray (optics), light rays from it to produce a real image of the object. Objectives can be a single Lens (optics), lens or mirror, or combinations of several optical elements. They are used in microscopes, binoculars, telescopes, cameras, slide projectors, CD players and many other optical instruments. Objectives are also called object lenses, object glasses, or objective glasses. Microscope objectives The objective lens of a microscope is the one at the bottom near the sample. At its simplest, it is a very high-powered magnifying glass, with very short focal length. This is brought very close to the specimen being examined so that the light from the specimen comes to a focus inside the microscope tube. The objective itself is usually a cylinder containing one or more lenses that are typically made of glass; its function is to collect light fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadmium
Cadmium is a chemical element; it has chemical symbol, symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12 element, group 12, zinc and mercury (element), mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in group 3 element, groups 3 through group 11 element, 11. Cadmium and its Congener (chemistry), congeners in group 12 are often not considered transition metals, in that they do not have partly filled ''d'' or ''f'' electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earth's crust is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Friedrich Stromeyer, Stromeyer and Karl Samuel Leberecht Hermann, Hermann, both in Germany, as an impurity in zinc carbonate. Cadmium occurs as a minor component in most zinc ores and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury-vapour Lamp
A mercury-vapor lamp is a gas-discharge lamp that uses an electric arc through vaporized mercury to produce light. The arc discharge is generally confined to a small fused quartz arc tube mounted within a larger soda lime or borosilicate glass bulb. The outer bulb may be clear or coated with a phosphor; in either case, the outer bulb provides thermal insulation, protection from the ultraviolet radiation the light produces, and a convenient mounting for the fused quartz arc tube. Mercury-vapor lamps are more energy efficient than incandescent lamps with luminous efficacies of 35 to 55 lumens/watt. Their other advantages are a long bulb lifetime in the range of 24,000 hours and a high-intensity light output. For these reasons, they are used for large area overhead lighting, such as in factories, warehouses, and sports arenas as well as for streetlights. Clear mercury lamps produce a greenish light due to mercury's combination of spectral lines. This is not flattering to h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visible Spectrum
The visible spectrum is the spectral band, band of the electromagnetic spectrum that is visual perception, visible to the human eye. Electromagnetic radiation in this range of wavelengths is called ''visible light'' (or simply light). The optical spectrum is sometimes considered to be the same as the visible spectrum, but some authors define the term more broadly, to include the ultraviolet and infrared parts of the electromagnetic spectrum as well, known collectively as ''optical radiation''. A typical human eye will respond to wavelengths from about 380 to about 750 nanometers. In terms of frequency, this corresponds to a band in the vicinity of 400–790 Terahertz (unit), terahertz. These boundaries are not sharply defined and may vary per individual. Under optimal conditions, these limits of human perception can extend to 310 nm (ultraviolet) and 1100 nm (near infrared). The spectrum does not contain all the colors that the human visual system can distinguish. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength
In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves), phase'' on the wave, such as two adjacent crests, troughs, or zero crossings. Wavelength is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The multiplicative inverse, inverse of the wavelength is called the ''spatial frequency''. Wavelength is commonly designated by the Greek letter lambda (''λ''). For a modulated wave, ''wavelength'' may refer to the carrier wavelength of the signal. The term ''wavelength'' may also apply to the repeating envelope (mathematics), envelope of modulated waves or waves formed by Interference (wave propagation), interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed phase velocity, wave speed, wavelength is inversely proportion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Zeiss AG
Zeiss ( ; ) is a German manufacturer of optical systems and optoelectronics, founded in Jena, Germany, in 1846 by optician Carl Zeiss. Together with Ernst Abbe (joined 1866) and Otto Schott (joined 1884) he laid the foundation for today's multinational company. The current company emerged from a reunification of Carl Zeiss companies in East and West Germany with a consolidation phase in the 1990s. ZEISS is active in four business segments with approximately equal revenue (Industrial Quality and Research, Medical Technology, Consumer Markets and Semiconductor Manufacturing Technology) in almost 50 countries, has 30 production sites and around 25 development sites worldwide. Carl Zeiss AG is the holding of all subsidiaries within Zeiss Group, of which Carl Zeiss Meditec AG is the only one that is traded at the stock market. Carl Zeiss AG is owned by the foundation Carl-Zeiss-Stiftung. The Zeiss Group has its headquarters in southern Germany, in the small town of Oberkochen, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moritz Von Rohr
Moritz von Rohr (4 April 1868 – 20 June 1940) was an optical scientist at Carl Zeiss in Jena, Germany. A street in Jena is named after him: Moritz-von-Rohr-Straße, near Carl-Zeiss-Promenade and Otto-Schott-Straße. Life Moritz von Rohr was born in Lonzyn near Hohensalza, then part of the Prussian Grand Duchy of Posen, but now in Poland and known as Łążyn, near Inowrocław. He obtained a doctorate of philosophy at the University of Berlin in 1892. Inventions Von Rohr is usually credited with the design of the first aspheric lenses for eyeglasses. He invented the eyeglass lens designs that became the Zeiss Punktal lenses. He also developed a method of computing depth of field from a camera's entrance pupil location and diameter, without reference to focal length and f-number An f-number is a measure of the light-gathering ability of an optical system such as a camera lens. It is calculated by dividing the system's focal length by the diameter of the entran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
