Einsteinium is a synthetic element with the symbol Es and atomic number 99. Einsteinium is a member of the actinide series and it is the seventh transuranium element. It was named in honor of Albert Einstein.
Fermium is a synthetic element with the symbol Fm and atomic number 100. It is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared. A total of 19 isotopes are known, with 257Fm being the longest-lived with a half-life of 100.5 days.
Morphogenesis is the biological process that causes a cell, tissue or organism to develop its shape. It is one of three fundamental aspects of developmental biology along with the control of tissue growth and patterning of cellular differentiation.
A synthetic element is one of 24 known chemical elements that do not occur naturally on Earth: they have been created by human manipulation of fundamental particles in a nuclear reactor, a particle accelerator, or the explosion of an atomic bomb; thus, they are called "synthetic", "artificial", or "man-made". The synthetic elements are those with atomic numbers 95–118, as shown in purple on the accompanying periodic table: these 24 elements were first created between 1944 and 2010. The mechanism for the creation of a synthetic element is to force additional protons into the nucleus of an element with an atomic number lower than 95. All synthetic elements are unstable, but they decay at widely varying rates: the half-lives of their longest-lived isotopes range from microseconds to millions of years.
Frederick Sanger was an English biochemist who received the Nobel Prize in Chemistry twice.
Sir Andrew Fielding Huxley was an English physiologist and biophysicist. He was born into the prominent Huxley family. After leaving Westminster School in central London, he went to Trinity College, Cambridge on a scholarship, after which he joined Alan Lloyd Hodgkin to study nerve impulses. Their eventual discovery of the basis for propagation of nerve impulses earned them the Nobel Prize in Physiology or Medicine in 1963. They made their discovery from the giant axon of the Atlantic squid. Soon after the outbreak of the Second World War, Huxley was recruited by the British Anti-Aircraft Command and later transferred to the Admiralty. After the war he resumed research at the University of Cambridge, where he developed interference microscopy that would be suitable for studying muscle fibres.
An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and in some plant cells. Certain endocrine cells such as pancreatic beta cells, and certain cells of the anterior pituitary gland are also excitable cells.
Haemophilia B, also spelled hemophilia B, is a blood clotting disorder causing easy bruising and bleeding due to an inherited mutation of the gene for factor IX, and resulting in a deficiency of factor IX. It is less common than factor VIII deficiency.
Sir Alan Lloyd Hodgkin was an English physiologist and biophysicist who shared the 1963 Nobel Prize in Physiology or Medicine with Andrew Huxley and John Eccles.
The year 1949 in science and technology involved some significant events, listed below.
Escherichia virus T4 is a species of bacteriophages that infect Escherichia coli bacteria. It is a double-stranded DNA virus in the subfamily Tevenvirinae from the family Myoviridae. T4 is capable of undergoing only a lytic lifecycle and not the lysogenic lifecycle. The species was formerly named T-even bacteriophage, a name which also encompasses, among other strains, Enterobacteria phage T2, Enterobacteria phage T4 and Enterobacteria phage T6.
Alfred Day Hershey was an American Nobel Prize–winning bacteriologist and geneticist.
Eric Francis Wieschaus is an American evolutionary developmental biologist and 1995 Nobel Prize-winner.
The Hodgkin–Huxley model, or conductance-based model, is a mathematical model that describes how action potentials in neurons are initiated and propagated. It is a set of nonlinear differential equations that approximates the electrical characteristics of excitable cells such as neurons and muscle cells. It is a continuous-time dynamical system.
The Department of Physiology, Development and Neuroscience, (PDN) is a part of the School of Biological Sciences at the University of Cambridge. Research in PDN focuses on three main areas: Cellular and Systems Physiology, Developmental and Reproductive Biology, and Neuroscience and is currently headed by Sarah Bray and William Colledge. The department was formed on 1 January 2006, within the School of Biological Sciences at the University of Cambridge from the merger of the Departments of Anatomy and Physiology. The department hosts the Centre for Trophoblast Research and has links with the Cambridge Centre for Brain Repair, the Cambridge Stem Cell Institute, and the Gurdon Institute.
Neural accommodation or neuronal accommodation occurs when a neuron or muscle cell is depolarised by slowly rising current in vitro. The Hodgkin–Huxley model also shows accommodation. Sudden depolarisation of a nerve evokes propagated action potential by activating voltage-gated fast sodium channels incorporated in the cell membrane if the depolarisation is strong enough to reach threshold. The open sodium channels allow more sodium ions to flow into the cell and resulting in further depolarisation, which will subsequently open even more sodium channels. At a certain moment this process becomes regenerative and results in the rapid ascending phase of action potential. In parallel with the depolarisation and sodium channel activation, the inactivation process of the sodium channels is also driven by depolarisation. Since the inactivation is much slower than the activation process, during the regenerative phase of action potential, inactivation is unable to prevent the "chain reaction"-like rapid increase in the membrane voltage.
Gilbert Ning Ling was a Chinese-born American cell physiologist, biochemist and scientific investigator.
The sliding filament theory explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement. According to the sliding filament theory, the myosin of muscle fibers slide past the actin during muscle contraction, while the two groups of filaments remain at relatively constant length.
Rosemary Peyton Biggs was an English haematologist. She worked closely with Robert Gwyn Macfarlane at the Radcliffe Infirmary and Churchill Hospital in Oxford, where she studied coagulation disorders, particularly haemophilia.
The Hodgkin family is a British Quaker family where several members have excelled in science, medicine, and arts.