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Mary Logan Reddick
Mary Logan Reddick (31 December 1914 – 1 October 1966) was an American neuroembryologist who earned her PhD from Radcliffe College, Harvard University in 1944. She was a full professor, first at Morehouse College, and then at the University of Atlanta from 1953 to her death. Her doctoral dissertation was on the study of chick embryos, and she went on to do research with time-lapse microscopy (then called motion picture microphotography) in tissue cultures. In 1952, Reddick received a Ford science fellowship to study at Cambridge University. Reddick was possibly the first African-American woman scientist to receive this fellowship for study abroad, and she was the first female biology instructor at Morehouse College. Early life and education Mary Reddick was born in Atlanta, Georgia in 1914. She graduated from the Laboratory High School and started majoring in biology at Spelman College in 1929 at the age of 15. Spelman is a women's historically black college, affiliated wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlanta
Atlanta ( ) is the capital and most populous city of the U.S. state of Georgia. It is the seat of Fulton County, the most populous county in Georgia, but its territory falls in both Fulton and DeKalb counties. With a population of 498,715 living within the city limits, it is the eighth most populous city in the Southeast and 38th most populous city in the United States according to the 2020 U.S. census. It is the core of the much larger Atlanta metropolitan area, which is home to more than 6.1 million people, making it the eighth-largest metropolitan area in the United States. Situated among the foothills of the Appalachian Mountains at an elevation of just over above sea level, it features unique topography that includes rolling hills, lush greenery, and the most dense urban tree coverage of any major city in the United States. Atlanta was originally founded as the terminus of a major state-sponsored railroad, but it soon became the convergence point among several rai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luther Williams
Luther may refer to: People * Martin Luther (1483–1546), German monk credited with initiating the Protestant Reformation * Martin Luther King Jr. (1929-1968), American minister and leader in the American civil rights movement * Luther (given name) * Luther (surname) Places * Luther (crater), a lunar crater named after astronomer Robert Luther * Luther, Indiana, an unincorporated community in the United States * Luther, Iowa, a town in Boone County, Iowa, United States * Luther, Michigan, a village in Lake County, United States * Luther, Montana, an unincorporated community in Carbon County, United States * Luther, Oklahoma, a town in Oklahoma County, Oklahoma, United States Arts, entertainment, and media Fictional characters * Luther, a character from '' The Adventures of Luther Arkwright'' limited comic book series * Luther, a gang member in ''The Warriors'' (1979) American cult film * Luther Bentley, the villain of ''Adventures of Captain Marvel'' (1941) * Luthe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesoderm
The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical Embryology, 11th edition. 2010. The mesoderm forms mesenchyme, mesothelium, non-epithelial blood cells and coelomocytes. Mesothelium lines coeloms. Mesoderm forms the muscles in a process known as myogenesis, septa (cross-wise partitions) and mesenteries (length-wise partitions); and forms part of the gonads (the rest being the gametes). Myogenesis is specifically a function of mesenchyme. The mesoderm differentiates from the rest of the embryo through intercellular signaling, after which the mesoderm is polarized by an organizing center. The position of the organizing center is in turn determined by the regions in which beta-catenin is protected from degradation by GSK-3. Beta-catenin acts as a co-factor that alters the activity of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectoderm
The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from the outer layer of germ cells. The word ectoderm comes from the Greek ''ektos'' meaning "outside", and ''derma'' meaning "skin".Gilbert, Scott F. Developmental Biology. 9th ed. Sunderland, MA: Sinauer Associates, 2010: 333-370. Print. Generally speaking, the ectoderm differentiates to form epithelial and neural tissues (spinal cord, peripheral nerves and brain). This includes the skin, linings of the mouth, anus, nostrils, sweat glands, hair and nails, and tooth enamel. Other types of epithelium are derived from the endoderm. In vertebrate embryos, the ectoderm can be divided into two parts: the dorsal surface ectoderm also known as the external ectoderm, and the neural plate, which invaginates to form the neural tube and neural crest. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Differentiation
Cellular differentiation is the process in which a stem cell alters from one type to a differentiated one. Usually, the cell changes to a more specialized type. Differentiation happens multiple times during the development of a multicellular organism as it changes from a simple zygote to a complex system of tissues and cell types. Differentiation continues in adulthood as adult stem cells divide and create fully differentiated daughter cells during tissue repair and during normal cell turnover. Some differentiation occurs in response to antigen exposure. Differentiation dramatically changes a cell's size, shape, membrane potential, metabolic activity, and responsiveness to signals. These changes are largely due to highly controlled modifications in gene expression and are the study of epigenetics. With a few exceptions, cellular differentiation almost never involves a change in the DNA sequence itself. Although metabolic composition does get altered quite dramaticall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Necessity And Sufficiency
In logic and mathematics, necessity and sufficiency are terms used to describe a material conditional, conditional or implicational relationship between two Statement (logic), statements. For example, in the Conditional sentence, conditional statement: "If then ", is necessary for , because the Truth value, truth of is guaranteed by the truth of (equivalently, it is impossible to have without ). Similarly, is sufficient for , because being true always implies that is true, but not being true does not always imply that is not true. In general, a necessary condition is one that must be present in order for another condition to occur, while a sufficient condition is one that produces the said condition. The assertion that a statement is a "necessary ''and'' sufficient" condition of another means that the former statement is true if and only if the latter is true. That is, the two statements must be either simultaneously true, or simultaneously false. In ordinary English (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primitive Knot
The primitive node (or primitive knot) is the organizer for gastrulation in most amniote embryos. In birds it is known as Hensen's node, and in amphibians it is known as the Spemann-Mangold organizer. It is induced by the Nieuwkoop center in amphibians, or by the posterior marginal zone in amniotes including birds. Diversity * In birds the organizer is known as Hensen's node, named after its discoverer Victor Hensen. * In other amniotes it is known as the primitive node. * In amphibians, it is known as the Spemann-Mangold organizer, named after Hans Spemann and Hilde Mangold, who first identified the organizer in 1924.) * In fish it is known as the embryonic shield. All structures are as yet considered as homologous. This view is substantiated by the common expression of several genes, including goosecoid, Cnot, noggin, nodal, and the sharing of strong axis-inducing properties upon transplantation. Cell fate studies have revealed that also the overall temporal sequence i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chorioallantoic Membrane
The Chorioallantoic Membrane (CAM), also known as the chorioallantois, is a highly vascularized membrane found in the eggs of certain amniotes like birds and reptiles. It is formed by the fusion of the mesodermal layers of two extra-embryonic membranes – the chorion and the allantois. It is the avian homologue of the mammalian placenta. It is the outermost extra-embryonic membrane which lines the non-vascular egg shell membrane. Structure The chorioallantoic membrane is composed of three layers. The first is the chorionic epithelium that is the external layer present immediately below the shell membrane. It consist of epithelial cells that arise from chorionic ectoderm. The second is the intermediate mesodermal layer that consists of mesenchymal tissue formed by the fusion of the mesodermal layer of the chorion and the mesodermal layer of the allantois. This layer is highly vascularized and rich in stromal components. The third is the allantoic epithelium that consists of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhode Island Red
The Rhode Island Red is an American breed of domestic chicken. It is the state bird of Rhode Island. It was developed there and in Massachusetts in the late nineteenth century, by cross-breeding birds of Oriental origin such as the Malay with brown Leghorn birds from Italy. It was a dual-purpose breed, raised both for meat and for eggs; modern strains have been bred for their egg-laying abilities. The traditional non-industrial strains of the Rhode Island Red are listed as "watch" (medium conservation priority, between "recovering" and "threatened") by The Livestock Conservancy. It is a separate breed to the Rhode Island White. History The Rhode Island Red was bred in Rhode Island and Massachusetts in the second half of the nineteenth century, by selective breeding of birds of Oriental origin such as the Cochin, Java, Malay and Shanghai with brown Leghorn birds from Italy. The characteristic deep red plumage derived from the Malay. The State of Rhode Island celebrated the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leghorn Chicken
The Leghorn (, ; it, Livorno, italic=no or Livornese) is a breed of chicken originating in Tuscany, in central Italy. Birds were first exported to North America in 1828 from the Tuscan port city of Livorno, on the western coast of Italy. They were initially called "Italians", but by 1865 the breed was known as "Leghorn", the traditional anglicisation of "Livorno". The breed was introduced to Britain from the United States in 1870. White Leghorns are commonly used as layer chickens in many countries of the world. Other Leghorn varieties are less common. History The origins of the Leghorn are not clear; it appears to derive from light breeds originating in rural Tuscany. The name comes from Leghorn, the traditional anglicisation of Livorno, the Tuscan port from which the first birds were exported to North America. The date of the first exports is variously reported as 1828, "about 1830" and 1852. They were initially known as "Italians"; they were first referred to as "Leghor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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