Glossary
Modified from:
Dr. Peter Van Osta's Web site http://www.whatis.com/nfindex.htm
Science Kit & Boreal Laboratories
A
Aberration An optical defect in a lens causing the lens to form an image that is not sharp or that is distorted.
Abbe condenser: A condenser invented by Ernst Abbe, a German physicist. It consists of two lens elements, the top element being removable for low power observation or photography.
Achromatic objectives: objectives designed to bring the red and blue parts of the visible light spectrum into the same focus while bringing green and other colors into a shorter focus.
Acrylic resin: Thermoplastic derivative of acrylic acid or its ester. A monomer.
Airy Disc: An airy disc is the smallest image a microscope or telescope can make of a point source of light. Defraction as the light passes through the aperture causes the image of even a point source to have a finite size.
A.F.M.: Atomic Force Microscope, used to image the surface of specimens at the atomic level.
Aperture: Opening that allows light to pass through a lens. While most cameras and enlargers use an adjustable aperture as one control of light, objective lenses in microscopes do not have such adjustments. Instead, microscope objectives have a fixed aperture.
Arm: The main vertical section supporting a microscope.
Artifact See fixation artifacts.
B
Background noise The result of electronic amplification of electronic current inherent in CCD cameras. Resulting images appear to be speckled with random dots like the snowy picture of a poor television picture.
Base: The main horizontal section which supports the microscope
Binocular A microscope having 2 eyepieces, one for each eye.
Bright field ??
C
Camera obscura: From the Latin "dark chamber." A camera obscura took on several forms, it could be darkened box or room with a small opening on one side. Light rays enter through the small opening and form an image of the scene outside. In its box form it is sometimes called a pinhole camera.
Carcinogens: Are chemicals which cause cancer.
Centipoise: (centi pwahz) -- (cps) Unit of viscosity -- the number of grams per centimeter per second flow.
Chromatic aberration: A defect of simple lenses that causes the light rays of different colors to focus at different planes resulting in images being fringed or haloed with extraneous color.
CCD: Acronym for Charged Coupled Device is used to capture photos on a grid array that can then be converted to digital images. CCD's are used in common video cameras and also on ultra-sensitive light gathering cameras for microscopy and astronomy. In some cases, CCD's can register as little as a single photon event.
Coarse focus adjustment knob: The control used to move the objective lens or stage up and down during initial focusing on a specimen. The amount of movement of the stage or lens is greater in proportion to the movement of the knob than for the fine focus adjustment knob.
Coaxial coarse and fine focus: Having both the coarse and fine focus operate on a single axis, so the knobs are concentric (usually with the coarse focus being the larger of the two knobs on the same side).
Compound lens: Lenses or objectives that make use of multiple lens configurations (convex and concave) to optimize image quality. Compound lenses can reduce both chromatic and spherical aberrations.
Compound microscope: an instrument fitted with objective and ocular (eyepiece) lenses and used for viewing small objects.
Combustible liquid: Any liquid having a flashpoint at or above 100oF (37.8oC), but below 200oF (93.3oC).
Compressed gas: A gas or mixture of gases having, in a container, an absolute pressure exceeding 40 psi at 70 F (21.1 C); a gas or mixture of gases having, in a container, an absolute pressure exceeding 104 psi at 130 oF (54.4oC) regardless of the pressure at 70oF, or a liquid having a vapor pressure exceeding 40 psi at 100oF (37.8oC).
Condenser: A mirror, lens or combination of lenses located under the microscope stage; used to gather light and direct it onto the object being viewed.
Concave lens: From the Latin word concavus meaning hollow. Lenses of this type have a hollow bowl shape.
Concavo-concave lens: Lenses that are concave on both sides
Concavo-convex lens Lenses that are concave on one side and convex on the other making the lens thinnest in the middle.
Corrosives: Are chemicals that cause visible destruction or, or irreversible alterations in, living tissue by chemical action at the site of initial contact.
Coverglass (coverslip): The thin piece of glass which sits over the specimen on the slide.
Convex lens: From the Latin word convexus meaning vaulted or arched. Lenses of this type curve outward in an arch shape.
D
Dark Current: The inherent electronic current in CCD devices. The dark current, when amplified causes noise. Noise is similar to the snowy image one might see when viewing a bad television transmission.
Dark-Field Microscopy: In dark field microscopy the condenser is modified so that light hits the specimen from the side, and is reflected toward the objective when it strikes an object. The background is black and objects appear bright, often with false colors.
Deflection Temperature The heat of distortion. Epoxies, 90-180oC. Therefore, polymerize at max. 75oC.
Depth-of-Field: The vertical distance that can be sharply focused on a specimen. The area between the nearest and the farthest points of a imaging device that are acceptably sharp. Not to be confused with true focus. Sometimes this is referred to as Z resolution. As the power of magnification increases, the depth of field decreases for any given microscope.
Depth-of-Focus: *The small range of error allowed when focusing an acceptably sharp image is produced when focusing a lens. The depth-of-focus is based on the subject to lens distance and the size of the lens aperture.
DIC: Acronym for Differential Interference Contrast. DIC is one of several methods used to increase the contrast of an unstained sample so that it can be viewed through a microscope. Other such techniques to increase contrast include, Phase Contrast and Hoffman Modulation Contrast (HMC).
Disc diaphragm: A disc with five or six different sized holes fitted under the stage of a microscope. As the disc is turned, one after another of the holes swings in place beneath the opening on the stage for the light. It controls the amount of light that passes up through the specimen slide.
Dry lens: Microscope lenses that require no immersion medium to view a sample. Dry lenses, while convenient, lack the ability to magnify objects beyond 400X.
Dovetail: Two intermeshing plates which engage each other with two interlocking inclined surfaces broader at the ends than the bases.
E
EIDE: Enhanced IDE. The faster version of the IDE storage drive.
Epoxy Resin Thermosetting resin made from the polymerization of an epoxide (a cyclic ether). Usually O2 epichlorohydrin and bisphenyl CH2 CH2.
Epoxy Equivalent Weight: The weight of epoxy in grams, containing 1 gram of chemical epoxide.
Exotherm: The increasing heat of the mixture caused by the heat of polymerization. If not controlled and becomes too high, can cause distortion and bubbling.
Explosive: A chemical that causes a sudden release of pressure, gas, and heat when subjected to sudden shock, pressure or high temperature.
Eyepiece (ocular): The lens system closest to the eye. It is the component of the compound microscope that magnifies the primary image of the objective.
F
FAQ: Acronym for Frequently Asked Questions. A FAQ is a file or
document where a moderator or administrator will post commonly
asked questions and their answers. Although it is very easy to
communicate across the Internet, if you have a question, you should
check for the answer in a FAQ first.
Fixation: (To Fix) The act of killing, stopping all: movement, enzamatic and metabolic activity within a cell or tissue. The process usually gells
the cytosol and stabilizes the material for later processing. In
photography to remove all undeveloped silver grains rendering the
photograph stable.
Fixation Artifact: Distortions of cells and cellular tissue that would not be present in a living cell.
Fluorescence: A word coined by George Stokes in 1852 which describes light emission induced during excitation.
FTP This stands for File Transfer Protocol. It is a procedure used to
transfer large files and programs from one computer to another.
Access to the computer to transfer files may or may not require a
password. Some FTP servers are set up to allow public access by
anonymous log-on. This process is referred to as Anonymous FTP.
Field of view: The area visible through the microscope. As the power of the objective increases, the size of the field of view decreases for any given microscope.
Fine focus objective knob: The control used to bring the specimen into sharp focus by moving the objective or stage up and down in very small increments.
Flammable: A chemical that falls into one of the following categories:
1. aerosol, flammable means an aerosol that yields a flame when ignited;
2. gas, flammable means a gas that at ambient temperature and pressure, forms a flammable mixture with air at a concentration of thirteen percent by volume or less, or a gas that, at ambient temperature and pressure, forms a range of flammable mixtures with air wider than twelve percent by volume, regardless of the lower limit;
3. liquid, flammable means any liquid having a flashpoint below 100oF (37.8oC),
4. solid, flammable means a solid, other than an explosive, that is liable to cause fire through friction, absorption of moisture, spontaneous chemical change, or retained heat from manufacturing or processing, or
which can be ignited readily and when ignited burns so vigorously and persistently as to create a serious hazard.
G
GIF: This stands for Graphics Interchange Format. It is a format created by CompuServe to allow electronic transfer of digital images. GIF files are a common and much used format and can be viewed by both Mac and Windows users. GIF files are a compressed file format, which makes them useful for web applications where minimizing file size is important.
Classified as a lossy compression, data is thrown away to achieve
the compressed file then extrapolated to return the file to full size.
H
Head: Top portion of the microscope, often inclined towards observer, contains mirrors or prisms and eyepieces.
Hematopoietic toxins Are chemicals which act on the blood system. Examples of signs and symptoms include cyanosis and loss of consciousness. Examples of chemicals which act on the hematopoietic system include carbon monoxide and cyanides.
Hepatotoxins: Are chemicals which produce liver damage. Example of signs and symptoms include jaundice and liver enlargement. Examples of chemicals which are hepatotoxins include carbon tetrachloride, nitrosamines.
High power objective: A lens with greater magnification ability. (40X-100X)
Highly toxic: Are chemicals which have an average lethal dose of:
1. Ingestion: LD50 of less than 50 mg/kg body weight when administered orally to albino rats;
2. Skin Contact: LD50 of less than 200 mg/kg body weight when administered by continuous dermal contact over a 24 hour period to albino rabbits.
3. Inhalation: LC50 of less than 200 parts per million of gas or vapor or 2 mg/l of mist, fume, or dust, when administered continuously by inhalation for one hour to albino rats.
Hoffman Modulation Contrast: Also known as HMC, this is yet another method to increase the contrast of an unstained sample so that it can be viewed through a microscope. Other such techniques to increase contrast include, phase contrast and differential interference contrast (DIC).
I
IDE: Intelligent Drive Electronics or Integrated Drive Electronics. This
refers to a mass storage device that integrates the controller for the drive on the drive. Faster versions of this drive are called EIDE (Enhanced IDE)
Immersion lens: Lenses that requires a liquid medium, usually oil or water, to be used. The immersion medium reduces the spread of of white light from refractive surface to refractive surface and reduces the blurring effect at the edges of a specimen. In contrast to dry lenses where resolution is unsatisfactory at final magnifications above 400X.
Immersion medium Liquid medium, usually oil or water used to increase the resolution of special objectives (immersion objectives) by reducing the spread of white light between refractive surfaces.
Iris diaphragm: A device under the microscope stage that uses a series of metal leaves that work together to control the size of the opening through which light passes into the condenser.
Irritants: Are chemicals which are not corrosive, but which cause a reversible inflammatory effect on living tissue by chemical action at the site of contact.
J
JPEG: This stands for Joint Photographic Experts Group. It is also commonly used to refer to a format used to transfer digital images. Classified as a lossy compression, data is thrown away to achieve the compressed file then extrapolated to return the file to full size.
K
L
Laser: An acronym for Light Amplification Stimulated Emission of Radiation. Lasers convert incident electromagnetic radiation of mixed frequencies to one of more discrete frequencies of highly amplified and coherent visible radiation. In other words, highly intense monochromatic light sources.
Lens: An optical device 1) either made of a solid shaped piece of transparent material that is capable of gathering light rays (photons) reflect them from a subject and focus them on a viewing plane or 2) a electromagnetic lens that Low power objective: lens with lower magnification ability. (4X-10X) (C5,C20) can focus electrons in a similar fashion on to a viewing plane.
M
Magnification: The number of times that a microscopic image appears larger that them original specimen.
Mechanical stage: Adevice to hold the specimen slide and move it to bring any part into the optical path or field of view.
MPEG: This stands for Motion Picture Experts Group. It is also a format
used to make, view, and transfer both digital audio and digital video
files.
Monocular: A microscope having only 1 eyepiece.
Monomer: Simple unpolymerized form of a chemical compound having a relatively low molecular weight. Less crosslinking of these monomers gives a softer block which is easier to cut.
N
Nephrotoxins: Are chemicals which produce kidney damage. Examples of signs and symptoms include edema (retention of water) and proteinuria (protein in the urine). Examples of chemicals which are nephrotoxins include halogenated hydrocarbons and uranium.
Neurotoxins: Are chemicals which produce their primary toxic effects on the nervous system. Examples of signs and symptoms include behavioral changes, decrease in motor functions. Examples of chemicals which are neurotoxins include mercury and carbon disulfide.
Nosepiece: The rotating device that holds the objective lenses. objective: lens closest to the object being magnified.
Numerical aperture: ??
O
Oil immersion objective: An objective lens system used for obtaining very high magnification. In use, the objective lens is immersed in a drop of oil that is in contact with the cover glass on the slide.
Organic peroxide: An organic compound that contains the bivalent -O-O- structure and which may be considered to be a structural derivative of hydrogen peroxide where one or both of the hydrogen atoms has been replaced by an organic radical. Organic peroxides are oxidizers and fuels in one, and are therefore unstable and potentially explosive. "Peroxidizable" means a chemical which will form organic peroxides when exposed to air.
OS: Acronym for Operating System. Fundamental set of commands and procedures used to run the hardware of a computer. In operation, a
software package communicates with the OS and the OS then performs
the needed command. There are four basic OS systems in use today. DOS (disk operating system), Windows (including Windows and WinNT),
Macintosh OS (specifically used for Macintosh computers) and UNIX.
Oxidizer: A chemical other than an explosive that initiates or promotes combustion in other materials, thereby causing fire either of itself or through the release of oxygen or other gases.
P
Parfocal lenses: Objective lenses that remain in focus when the magnification is changed.
Phase contrast Microscopy: Technique used to view unstained transparent or translucent specimens. Phase contrast takes advantage of different thicknesses within a specimen. For example, the nucleus of a cell is thicker than other parts of a cell. Light is retarded when passing through these thicker parts. The phase contrast microscope exploits the interference effects that take place when the two types of light recombine. If the waves complement each other the light is brighter, while if they are 180 degrees out of phase they cancel each other and the image is dark. Other such techniques to increase contrast include, Differential Interference Contrast (DIC) and Hoffman Modulation Contrast (HMC).
Pinion: A narrow gear with teeth cut around the circumference usually attached to a shaft. Engages with a rack.
Pixel Picture Element - Word created to describe the individual dots on a
computer screen.
Pixelation: The results of increasing the size of a bitmapped or raster image such that visible square dots appear. The edges of objects become jagged or stair-step in appearance.
Pneumotoxins: Are chemicals which irritate or damage the pulmonary tissue. Examples of signs and symptoms include tightness in the chest and shortness of breath. Examples of chemicals which damage the lungs include silica and asbestos.
Polyester: Complex ester formed by the condensation of a polyhydric alcohol with polybasic acid to give an ester and water. Polymer A natural or synthetic compound, or mixture of compounds formed by polymerization and consisting of repeating units.
Polymerization: A chemical reaction in which two or more small molecules combine to form larger molecules that contain repeating units.
PPP: Acronym for Point-to-Point-Protocol which is a well known protocol that allows a computer to use a regular telephone line and a modem to make TCP/IP connections. Once connected via a PPP connection direct access to the Internet is possible.
Pyrophoric: A chemical that will ignite spontaneously or explode in air at a temperature of 130oF (54.4oC) or below.
Q
QuickTime: This is a format used by Apple Computer to make, view, edit, and send digital audio and video.
R
Rack: A flat plate with gear teeth cut into it. Looks like a ladder.
Raster Raster images are made of an array of either 2-D or 3-D information. Image data is usually stored in a bitmapped form and sometimes these files are called bitmapped files. Examples of raster image files are TIFF, GIF and JPEG.
Reproductive toxins: Are chemicals which affect the reproductive capabilities including chromosomal damage (mutagens) and effects on the fetuses (teratogens). Examples of signs and symptoms include birth defects and sterility. Examples of chemicals which are reproductive toxins include lead and DBCP (dibromochloropropane).
Reticle(graticle): A glass disk, with a scale etched on it, to facilitate measuring or pointing out objects.
Resolution: 1) The ability to distinguish and separate one tiny structure from another magnification resolution that is defined as the minimum distance between objects that can be visually detected 2) both the quality of a monitor screen and image. Describes the output quality of an image on a hardcopy device such as a printer. Screen and image resolution are based on the number of pixels used to make the image (example: 1024 X 768). While hardcopy resolution is based on dots per square inch (example: 300 dpi).
S
Sensitizers: Are chemicals that cause a substantial proportion of exposed people or animals to develop an allergic reaction in normal tissue after repeated exposure to the chemical.
SCSI: Acronym for Small Computer System Interface, pronounced (scuzy). The most common components that makes use of the SCSI interface are SCSI hard drives. Generally, SCSI devices are faster than other interface devices.
SEM: Scanning Electron Microscope. Microscope that uses electrons rather than photons to view the surface of specimens.
Spherical aberration: An optical defect in a lens causing the lens to form an image that is not sharp or that is distorted. The larger the lens, the more likely it is to suffer from aberrations. Aberrations are also more common towards the outer portion of a lens.
Stop screw (focus): An adjustable screw either in the stage or beneath the focusing mechanism to prevent contact between the objective and the microscope slide ( Prevents damage to both.)
Stage: The flat surface the microscope sits on. Often has clips to hold the glass slide.
T
Telnet: This is the process of remotely connecting and using a computer at a distant location.
TEM: Transmission Electron Microscope. Microscope that uses electrons
rather than photons to view thin specimens.
Tension collar: An adjustable sleeve on the course focusing knob to avoid drift of focus.
Thermoplastic: Material that, on heating and pressure, soften and flow.
Thermoset Materials that once heated, react irreversibly, polymerizing and cannot be heated and reflowed.
TIFF: Acronym for Tagged Information File Format. Describes one form of graphic file format. TIFF files, sometimes called TIF files are the most
universal of graphic file formats. Typically they do not use any
compression method and therefore are larger than other types of graphic formats such as GIF and JPEG files. Even with compression no data is discarded.
Toxic: All chemicals are considered toxic. The Occupational Safety and Health Administration defines "toxic" as chemicals which have an average lethal dose (LD50) or lethal concentration (LC50, indicates average lethal inhalation exposure) of:
1. Ingestion: LD50 between 50 and 500 mg/kg body weight when administered orally to albino rats;
2. Skin Contact: LD50 between 200 and 1000 mg/kg body weight when administered by continuous dermal contact over a 24 hour period to albino rabbits.
3. Inhalation: LC50 between 200 and 2000 parts per million of gas or vapor or between 2 and 20 mg/l of mist, fume, or dust, when administered continuously by inhalation for one hour to albino rats.
Trinocular: A microscope having three eyepieces, one for each eye and one for a camera
True focus: The absolute plane where focus is accieved. Depending on the subject to lens distance and the size of the lens aperture an additional area in front and in back of true focus will also appear sharp and in focus. This extra area is called depth-of-field.
Turret (objective): The rotating plate which holds several objectives, objective plate.
U
UNIX: (pronounced "yew-nix") is one of the original time sharing operating systems developed at Bell Labs in 1969. Today many versions of UNIX that can run on many different computers are available.
Unstable (reactive) A chemical which in the pure state, or as produced or transported, will vigorously polymerize, decompose, condense, or will become self-reactive under conditions of shocks, pressure, or temperature.
V
Vector Graphics: Vector graphics, also known as geometric oriented graphics, describes software packages that use a sequence of commands or mathematical statements that place objects (lines and polygons) in a given two-dimensional or three-dimensional space.
Voxel Word created from two words (vector and pixel) to describe the 3-D space of a pixel based image. Pixel based files are commonly used with scanning-laser confocal microscopes. Multiple slices of a sample are
collect at different Z-planes and then reconstructed to create a projection image of the sample.
VRML: This stands for Virtual Reality Markup Language. It was developed to allow the creation of virtual reality worlds. Your browser may need a specific plug-in to view VRML pages.
W
Water-reactive: A chemical that reacts with water to release a gas that is either flammable or presents a health hazard.
WAV: This stands for Waveform sound format. It is a Microsoft Corporation format for encoding sound files.
Wide field eyepiece: An eyepiece with an entrance lens larger that on most types of eyepieces; it lends itself to varying eye point requirements.
Working distance: The distance between the front end of the objective and the specimen, when the specimen is in sharp focus.
Worm gear A long cylindrical gear with teeth cut spiraling the length. Looks similar to a screw.
X
X-ray: A high-energy photon with wavelength in the approximate range from 0.05 angstroms to 100 angstroms. The name X-ray was coined by its discoverer, Wilhelm Roentgen. Roentgen did not fully understand the
nature of this type of light and therefore used the "x" to symbolize the
unknown quantity.
Y
Z
Zip File: Zip files are usually a collection of files packaged into one file in order to transport them in an easy manner. Often zip files are compressed to save space and reduce download times. To zip or unzip a file a utility is required such as PFZIP, WINZIP and NETZIP. In some cases a self-extracting (exe) zip file can be created that does not require any utility to open and uncompress the files.
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