|
Membrane (other)
Membrane most commonly means a thin, selective barrier, but it is sometimes used for films that function as separators, like biological membranes. Membrane may also refer to: Biology: * Isolating tissues formed by layers of cells ** Amnion, a membrane in the amniotic sac ** Basement membrane, a thin sheet of fibers that underlies the epithelium ** Chorioallantoic membrane, a vascular membrane found in eggs of birds, reptiles and other animals ** Eardrum, more formally known as ''Tympanic membrane'' ** Fetal membrane, the amnion and chorion which surround and protect a developing fetus ** Mucous membrane, linings of mostly endodermal origin which are involved in absorption and secretion ** Serous membrane, a smooth membrane consisting of a thin layer of cells, which secrete serous fluid ** Tunic membrane, protective membrane covering the testes ** Patagium, also known as "flight membrane", in some flying and gliding animals ** Pterygium, a triangular membrane occurring in eyes * Cel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane
A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Biological membranes include cell membranes (outer coverings of cells or organelles that allow passage of certain constituents); nuclear membranes, which cover a cell nucleus; and tissue membranes, such as mucosae and serosae. Synthetic membranes are made by humans for use in laboratories and industry (such as chemical plants). This concept of a membrane has been known since the eighteenth century but was used little outside of the laboratory until the end of World War II. Drinking water supplies in Europe had been compromised by the war and membrane filters were used to test for water safety. However, due to the lack of reliability, slow operation, reduced selectivity and elevated costs, membranes were not widely exploited. The first us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pterygium
Pterygium (plural ''pterygia'' or ''pterygiums'') refers to any wing-like triangular membrane occurring in the neck, eyes, knees, elbows, ankles or digits. The term comes from the Greek word ''pterygion'' meaning "wing". Types * Popliteal pterygium syndrome, a congenital condition affecting the face, limbs, or genitalia but named after the wing-like structural anomaly behind the knee * Pterygium (eye) or surfer's eye, a growth on the cornea of the eye * Pterygium colli or webbed neck, a congenital skin fold of the neck down to the shoulders * Pterygium inversum unguis or ventral pterygium, adherence of the distal portion of the nailbed to the ventral surface of the nail plate * Pterygium unguis Pterygium unguis (or dorsal pterygiumFreedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. .) forms as a result of scarring between the proximal nailfold and matrix, with the classic example being liche ... or dorsal pterygium, scarring betw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane (M-Theory)
In string theory and related theories such as supergravity theories, a brane is a physical object that generalizes the notion of a point particle to higher dimensions. Branes are dynamical objects which can propagate through spacetime according to the rules of quantum mechanics. They have mass and can have other attributes such as charge. Mathematically, branes can be represented within categories, and are studied in pure mathematics for insight into homological mirror symmetry and noncommutative geometry. ''p''-branes A point particle can be viewed as a brane of dimension zero, while a string can be viewed as a brane of dimension one. In addition to point particles and strings, it is possible to consider higher-dimensional branes. A ''p''-dimensional brane is generally called "''p''-brane". The term "''p''-brane" was coined by M. J. Duff ''et al.'' in 1988; "brane" comes from the word "membrane" which refers to a two-dimensional brane. A ''p''-brane sweeps out a (''p''+ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane Structure
Membrane structures are spatial structures made out of tensioned membranes. The structural use of membranes can be divided into pneumatic structures, tensile membrane structures, and cable domes. In these three kinds of structure, membranes work together with cables, columns and other construction members to find a form. Membranes are also used as non-structural cladding, as at the Beijing National Stadium where the spaces between the massive steel structural members are infilled with PTFE coated glass fiber fabric and ETFE foil. The other major building on the site, built for the 2008 Summer Olympics, is the Beijing National Aquatics Center, also known as the Water Cube. It is entirely clad in 100,000 square metres of inflated ETFE foil cushions arranged as an apparently random cellular structure. Materials The common membranes used in membrane structures include: * PVC coated polyester fabric * Translucent Polyethylene fabric * PVC coated glass fiber fabric * PTFE coated gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane Keyboard
A membrane keyboard is a computer keyboard whose "keys" are not separate, moving parts, as with the majority of other keyboards, but rather are pressure pads that have only outlines and symbols printed on a flat, flexible surface. Very little, if any, tactile feedback is felt when using such a keyboard. Membrane keyboards work by electrical contact between the keyboard surface and the underlying circuits when keytop areas are pressed. These models were used with some early 1980s home computers, enjoying wide adoption in consumer electronics devices. The keyboards are quite inexpensive to mass-produce, and are more resistant against dirt and liquids than most other keyboards. However, due to a low or non-existent tactile feedback, most people have difficulty typing with them, especially when larger numbers of characters are being typed. Chiclet keyboards were a slight improvement, at least allowing individual keys to be felt to some extent. Aside from early hobbyist/kit/home comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membranophone
A membranophone is any musical instrument which produces sound primarily by way of a vibrating stretched membrane. It is one of the four main divisions of instruments in the original Hornbostel-Sachs scheme of musical instrument classification. According to Sachs, material, shape, skin(s), skin fastening, playing positions, and manner of playing. Hornbostel-Sachs The Hornbostel-Sachs scheme of musical instrument classification divides membranophones in a numeric taxonomy based on how the sound is produced: *21: by hitting the drumskin with a hand or object (most common form, including the timpani and snare drum) *22: by pulling a knotted string attached to the drumskin (common in Indian drums, and can be considered an example of a chordophone as well) *23: by rubbing the drumskin with a hand or object (common in Irish traditional music, an example is the bodhran) *24: by modifying sounds through a vibrating membrane (unusual form, including the kazoo) Length and breadth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Membrane
An acoustic membrane is a thin layer that vibrates and is used in acoustics to produce or transfer sound, such as a drum, microphone, or loudspeaker. See also * Membranophone * Vibrations of a circular membrane A two-dimensional elastic membrane under tension can support transverse vibrations. The properties of an idealized drumhead can be modeled by the vibrations of a circular membrane of uniform thickness, attached to a rigid frame. Due to the ph ... Acoustics Sound {{acoustics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outer Membrane (other) , of the nuclear envelope in eukaryotic cells
{{disambiguation ...
Outer membrane may refer to: * Bacterial outer membrane, of a gram negative bacterium cell * Outer mitochondrial membrane * Chloroplast outer membrane, of plant and algal cells * Outer nuclear membrane The nuclear envelope, also known as the nuclear membrane, is made up of two lipid bilayer membranes that in eukaryotic cells surround the nucleus, which encloses the genetic material. The nuclear envelope consists of two lipid bilayer membrane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inner Nuclear Membrane
The nuclear envelope, also known as the nuclear membrane, is made up of two lipid bilayer membranes that in eukaryotic cells surround the nucleus, which encloses the genetic material. The nuclear envelope consists of two lipid bilayer membranes: an inner nuclear membrane and an outer nuclear membrane. The space between the membranes is called the perinuclear space. It is usually about 10–50 nm wide. The outer nuclear membrane is continuous with the endoplasmic reticulum membrane. The nuclear envelope has many nuclear pores that allow materials to move between the cytosol and the nucleus. Intermediate filament proteins called lamins form a structure called the nuclear lamina on the inner aspect of the inner nuclear membrane and give structural support to the nucleus. Structure The nuclear envelope is made up of two lipid bilayer membranes, an inner nuclear membrane and an outer nuclear membrane. These membranes are connected to each other by nuclear pores. Two sets of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of cells and organelles, being selectively permeable to ions an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Membrane
A biological membrane, biomembrane or cell membrane is a selectively permeable membrane that separates the interior of a cell from the external environment or creates intracellular compartments by serving as a boundary between one part of the cell and another. Biological membranes, in the form of eukaryotic cell membranes, consist of a phospholipid bilayer with embedded, integral and peripheral proteins used in communication and transportation of chemicals and ions. The bulk of lipids in a cell membrane provides a fluid matrix for proteins to rotate and laterally diffuse for physiological functioning. Proteins are adapted to high membrane fluidity environment of the lipid bilayer with the presence of an annular lipid shell, consisting of lipid molecules bound tightly to the surface of integral membrane proteins. The cell membranes are different from the isolating tissues formed by layers of cells, such as mucous membranes, basement membranes, and serous membranes. Composition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flying And Gliding Animals
A number of animals are capable of aerial locomotion, either by powered flight or by gliding. This trait has appeared by evolution many times, without any single common ancestor. Flight has evolved at least four times in separate animals: insects, pterosaurs, birds, and bats. Gliding has evolved on many more occasions. Usually the development is to aid canopy animals in getting from tree to tree, although there are other possibilities. Gliding, in particular, has evolved among rainforest animals, especially in the rainforests in Asia (most especially Borneo) where the trees are tall and widely spaced. Several species of aquatic animals, and a few amphibians and reptiles have also evolved this gliding flight ability, typically as a means of evading predators. Types Animal aerial locomotion can be divided into two categories: powered and unpowered. In unpowered modes of locomotion, the animal uses aerodynamic forces exerted on the body due to wind or falling through the air. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_in_flight%2C_Cley%2C_Norfolk_1700.jpg "Click for more on -> Flying And Gliding Animals")