|
Ka Yee Christina Lee
Ka Yee Christina Lee () is Hong Kong-born American chemist. She is Executive Vice President for Strategic Initiatives and the David Lee Shillinglaw Distinguished Service Professor in the Department of Chemistry at the University of Chicago. She works on membrane biophysics, including protein–lipid interactions, Alzheimer's disease and respiratory distress syndrome. She is a Fellow of the American Institute for Medical and Biological Engineering and American Physical Society. Early life and education Lee was born in Hong Kong. Lee completed her bachelor's degree in electrical engineering at Brown University in 1986. She joined Harvard University for her graduate studies in applied physics, earning her master's in 1987 and PhD in 1992. She worked under the supervision of Eric Mazur on liquid-vapour interfaces. Lee was a postdoctoral researcher with Harden M. McConnell at Stanford University and with Joseph Zasadzinski at the University of California, Santa Barbara. Research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Hong Kong
Hong Kong was under British Empire, British rule from 1841 to 1997, except for a Japanese occupation of Hong Kong, brief period of Japanese occupation during World War II from 1941 to 1945. It was a crown colony of the United Kingdom from 1841 to 1981, and a British Dependent Territory, dependent territory from 1981 to 1997. The colonial period began with the British occupation of Hong Kong Island under the Convention of Chuenpi in 1841 of the Victorian era, and ended with the handover of Hong Kong to the China, People's Republic of China in July 1997. In accordance with Art. III of the Treaty of Nanking of 1842, signed in the aftermath of the First Opium War, the island of Hong Kong was ceded in perpetuity to Great Britain. It was established as a Crown colony in 1843. In 1860, the British expanded the colony with the addition of the Kowloon Peninsula and was further extended in 1898 when the British obtained Convention for the Extension of Hong Kong Territory, a 99-year lease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Applied Physics
Applied physics is the application of physics to solve scientific or engineering problems. It is usually considered a bridge or a connection between physics and engineering. "Applied" is distinguished from "pure" by a subtle combination of factors, such as the motivation and attitude of researchers and the nature of the relationship to the technology or science that may be affected by the work. Applied physics is rooted in the fundamental truths and basic concepts of the physical sciences but is concerned with the utilization of scientific principles in practical devices and systems and with the application of physics in other areas of science and high technology. Examples of research and development areas * Accelerator physics *Acoustics * Atmospheric physics *Biophysics * Brain–computer interfacing *Chemistry * Chemical physics * Differentiable programming **Artificial intelligence ** Scientific computing *Engineering physics **Chemical engineering **Electrical engineeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catechol
Catechol ( or ), also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound with the molecular formula . It is the ''ortho'' isomer of the three isomeric benzenediols. This colorless compound occurs naturally in trace amounts. It was first discovered by destructive distillation of the plant extract catechin. About 20,000 tonnes of catechol are now synthetically produced annually as a commodity organic chemical, mainly as a precursor to pesticides, flavors, and fragrances. Small amounts of catechol occur in fruits and vegetables. Isolation and synthesis Catechol was first isolated in 1839 by Edgar Hugo Emil Reinsch (1809–1884) by distilling it from the solid tannic preparation catechin, which is the residuum of catechu, the boiled or concentrated juice of ''Mimosa catechu'' ('' Acacia catechu''). Upon heating catechin above its decomposition point, a substance that Reinsch first named ''Brenz-Katechusäure'' (burned catechu acid) sublimated as a white efflo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byssal Thread
A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells ( Pinnidae), true mussels (Mytilidae), and Dreissenidae. Filaments Byssus filaments are created by certain kinds of marine and freshwater bivalve mollusks, which use the byssus to attach themselves to rocks, Substrate (marine biology), substrates, or seabeds. In edible mussels, the inedible byssus is commonly known as the "beard", and is removed before cooking. Many species of mussels secrete byssus threads to anchor themselves to surfaces, with Family (taxonomy), families including the Mytilidae The Mytilidae are a family (biology), family of small to large Marine life, marine and Brackish water, brackish-water bivalve molluscs in the order (biology), order Mytilida. One of the genera, ''Limnoperna fortunei, Limnoperna'', even inhabits f ..., Arcidae, Anomiidae, Pin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Force Microscopy
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. Overview Atomic force microscopy (AFM) gathers information by "feeling" or "touching" the surface with a mechanical probe. Piezoelectric elements that facilitate tiny but accurate and precise movements on (electronic) command enable precise scanning. Despite the name, the Atomic Force Microscope does not use the nuclear force. Abilities and spatial resolution The AFM has three major abilities: force measurement, topographic imaging, and manipulation. In force measurement, AFMs can be used to measure the forces between the probe and the sample as a function of their mutual separation. This can be applied to perform force spectroscopy, to measure the mechanical properties of the sample, such as the sample's Youn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Electron Microscopy
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device, such as a fluorescent screen, a layer of photographic film, or a detector such as a scintillator attached to a charge-coupled device or a direct electron detector. Transmission electron microscopes are capable of imaging at a significantly higher resolution than light microscopes, owing to the smaller de Broglie wavelength of electrons. This enables the instrument to capture fine detail—even as small as a single column of atoms, which is thousands of times smaller than a resolvable object seen in a light microscope. Transmission electron micr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myelin Sheath
Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. However, unlike the plastic covering on an electrical wire, myelin does not form a single long sheath over the entire length of the axon. Myelin ensheaths part of an axon known as an internodal segment, in multiple myelin layers of a tightly regulated internodal length. The ensheathed segments are separated at regular short unmyelinated intervals, called nodes of Ranvier. Each node of Ranvier is around one micrometre long. Nodes of Ranvier enable a much faster rate of conduction known as saltatory conduction where the action potential recharges at each node to jump over to the next node, and so on till it reaches the axon terminal. At the terminal the a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amyloid Precursor Protein
Amyloid-beta precursor protein (APP) is an integral membrane protein expressed in many biological tissue, tissues and concentrated in the synapses of neurons. It functions as a cell surface receptor and has been implicated as a regulator of synapse formation, neural plasticity, antimicrobial activity, and iron export. It is coded for by the gene ''APP'' and regulated by substrate presentation. APP is best known as the precursor molecule whose proteolysis generates amyloid beta (Aβ), a polypeptide containing 37 to 49 amino acid residues, whose Amyloid#Structure, amyloid fibrillar form is the primary component of amyloid plaques found in the brains of Alzheimer's disease patients. Genetics Amyloid-beta precursor protein is an ancient and highly Conserved sequence, conserved protein. In humans, the gene ''APP'' is located on chromosome 21 and contains 18 exons spanning 290 kilobases. Several alternative splicing isoforms of APP have been observed in humans, ranging in length ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amyloid Beta
Amyloid beta (Aβ, Abeta or beta-amyloid) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid-beta precursor protein (APP), which is cleaved by Beta-secretase 1, beta secretase and gamma secretase to yield Aβ in a cholesterol-dependent process and substrate presentation. Both neurons and oligodendrocytes produce and release Aβ in the brain, contributing to formation of amyloid plaques. Aβ molecules can aggregate to form flexible soluble oligomers which may exist in several forms. It is now believed that certain misfolded oligomers (known as "seeds") can induce other Aβ molecules to also take the misfolded oligomeric form, leading to a chain reaction akin to a prion infection. The oligomers are toxic to nerve cells. The other protein implicated in Alzheimer's disease, tau protein, also forms such prion-like misfolded oligomers, and there is some ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infant Respiratory Distress Syndrome
Infant respiratory distress syndrome (IRDS), also known as surfactant deficiency disorder (SDD), and previously called hyaline membrane disease (HMD), is a syndrome in premature infants caused by developmental insufficiency of pulmonary surfactant production and structural immaturity in the lungs. It can also be a consequence of neonatal infection and can result from a genetic problem with the production of surfactant-associated proteins. IRDS affects about 1% of newborns and is the leading cause of morbidity and mortality in preterm infants. Data have shown the choice of elective caesarean sections to strikingly increase the incidence of respiratory distress in term infants; dating back to 1995, the UK first documented 2,000 annual caesarean section births requiring neonatal admission for respiratory distress. The incidence decreases with advancing gestational age, from about 50% in babies born at 26–28 weeks to about 25% at 30–31 weeks. The syndrome is more frequent in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung Surfactant
Pulmonary surfactant is a surface-active complex of phospholipids and proteins formed by type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions. By adsorbing to the air-water interface of alveoli, with hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of the surfactant, dipalmitoylphosphatidylcholine (DPPC), reduces surface tension. As a medication, pulmonary surfactant is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system. Function * To increase pulmonary compliance. * To prevent atelectasis (collapse of the alveoli or atriums) at the end of expiration. * To facilitate recruitment of collapsed airways. Alveoli can be compared to gas in water, as the alveoli are wet and surround a central air space. The surface tension acts at the air-water interface and tends to make the bubble smaller (by ... [...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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
