optical tweezers

Laser cooling - Brief explanation. This technique works by tuning the frequency of light slightly below an electronic transition in the atom. Because the light is detuned to the "red" (i.e. at lower frequency) of the transition, the atoms will absorb more photons if they move towards the light source, due to the Doppler effect. Thus if one applies light from two opposite directions, the atoms will always scatter more photons from the laser beam pointing opposite to their direction of motion. In each scattering ev ...

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Laser cooling, Laser cooling - How it works, Laser cooling - Brief explanation, Laser cooling - Detailed explanation, Laser cooling - Limitations, Laser cooling - Configurations

Read more here: » Laser cooling: Encyclopedia II - Laser cooling - How it works

The term biophotonics denotes a combination of biology and photonics, with photonics being the science of direct manipulation of photons, quantum units of light. Photonics is related to electronics in that it is believed that photons will play a similar central role in future information technology as electrons do today. Biophotonics has therefore become the established general term for all techniques that deal with the relation of biological material and photons. This refers to emission, detection, absorption, reflection, modi ...

Including:

• Biophotonics - Applications

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A biopolymer is a polymer found in nature. Starch, proteins and peptides, DNA, and RNA are all examples of biopolymers, in which the monomer units, respectively, are sugars, amino acids, and nucleic acids. The exact chemical composition and the sequence in which these units are arranged is called the polymer's primary structure. Many biopolymers spontaneously "fold" into characteristic shapes, which determine their biological functions and depend in a complicated way on their primary structures. Structural b ...

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Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and most viruses). DNA is a long polymer of nucleotides and encodes the sequence of the amino acid residues in proteins using the genetic code, a triplet code of nucleotides. In complex cells (eukaryotes), such as those from plants, animals, fungi and protists, most of the DNA is located in the cell nucleus. By contrast, in simpler cells called prokaryotes (the eubacter ...

Including:

• DNA - Overview
• DNA - DNA in practice
• DNA - DNA in crime
• DNA - DNA in computation
• DNA - Overview of molecular structure
• DNA - The role of the sequence
• DNA - DNA replication
• DNA - Mechanical properties relevant to biology
• DNA - Strands association and dissociation
• DNA - Circular DNA
• DNA - Great length versus tiny breadth
• DNA - Entropic stretching behavior
• DNA - Different helix geometries
• DNA - Non-helical forms
• DNA - Direction of DNA strands
• DNA - Chemical nomenclature 5' and 3'
• DNA - Sense and antisense
• DNA - Distinction between sense and antisense strands
• DNA - As viewed by topologists
• DNA - Single-stranded DNA ssDNA and repair of mutations
• DNA - The history of DNA research
• DNA - First isolation of DNA
• DNA - Establishing a link between heritable traits and chromosomes
• DNA - Discovery of the structure of DNA
• DNA - Bibliography

Read more here: » DNA: Encyclopedia - DNA

The worm-like chain (WLC) model in polymer physics is used to describe the behavior of semi-flexible polymers; it is sometimes referred to as the Kratky-Porod worm-like chain model. Worm-like chain - Theoretical Considerations. The WLC model envisions an isotropic rod that is continuously flexible; this is in contrast to the freely-jointed chain model that is flexible only between discrete segments. The worm-like chain model is particularly suited for describing stiffer polymers. At room tempe ...

Including:

• Worm-like chain - Theoretical Considerations
• Worm-like chain - Biological Relevance
• Worm-like chain - Stretching Worm-like Chain Polymers

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Carlos Bustamante (* 1951 at Lima, Peru) In 2001 Time Magazine considered him as one of the best scientists in the USA. He is a member of the National Academy of Sciences. Carlos Bustamante - Bio. Dr. Bustamante is also Professor of Molecular and Cell Biology, Physics, and Chemistry at the University of California, Berkeley. He received his B.S. degree from Cayetano Heredia University in Lima, Peru; his masters in biochemistry from San Marcos University; and his Ph.D. degree in biophysics from UC Ber ...

Including:

• Carlos Bustamante - Bio
• Carlos Bustamante - Research Focus
• Carlos Bustamante - Academic Background

Read more here: » Carlos Bustamante: Encyclopedia - Carlos Bustamante

Dr. Bustamante is also Professor of Molecular and Cell Biology, Physics, and Chemistry at the University of California, Berkeley. He received his B.S. degree from Cayetano Heredia University in Lima, Peru; his masters in biochemistry from San Marcos University; and his Ph.D. degree in biophysics from UC Berkeley, where he studied with Ignacio Tinoco, Jr. As a postdoctoral fellow at the Lawrence Berkeley National Laboratory, Dr. Bustamante studied with Marc Maestre. He was a member of the chemistry department at the University of New Mexico i ...

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Carlos Bustamante, Carlos Bustamante - Bio, Carlos Bustamante - Research Focus, Carlos Bustamante - Academic Background

Read more here: » Carlos Bustamante: Encyclopedia II - Carlos Bustamante - Bio

The WLC model envisions an isotropic rod that is continuously flexible; this is in contrast to the freely-jointed chain model that is flexible only between discrete segments. The worm-like chain model is particularly suited for describing stiffer polymers. At room temperature, the polymer adopts a conformational ensemble that is smoothly curved; at T = 0 K, the polymer adopts a rigid rod conformation. For a polymer of length l, parametrize the path of the p ...

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Worm-like chain, Worm-like chain - Theoretical Considerations, Worm-like chain - Biological Relevance, Worm-like chain - Stretching Worm-like Chain Polymers

Read more here: » Worm-like chain: Encyclopedia II - Worm-like chain - Theoretical Considerations

This section presents an introductory and therefore incomplete overview of DNA. Genes can be loosely viewed as the organism's "cookbook" or "blueprint"; A strand of DNA contains genes, areas that regulate genes, and areas that either have no function, or a function which we do not (yet) know: also see last bullet point in this section for the difference between DNA and RNA; DNA is organized as two complementary strands, head-to-toe, with bonds between them that can be "unzipped" like a zipper, separating the st ...

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DNA, DNA - Overview, DNA - DNA pairing, DNA - DNA in practice, DNA - DNA in crime, DNA - DNA in computation, DNA - Overview of molecular structure, DNA - The role of the sequence, DNA - DNA replication, DNA - Mechanical properties relevant to biology, DNA - Strands association and dissociation, DNA - Circular DNA, DNA - Great length versus tiny breadth, DNA - Entropic stretching behavior, DNA - Different helix geometries, DNA - Non-helical forms, DNA - Direction of DNA strands, DNA - Chemical nomenclature 5' and 3', DNA - Sense and antisense, DNA - Distinction between sense and antisense strands, DNA - As viewed by topologists, DNA - Single-stranded DNA ssDNA and repair of mutations, DNA - The history of DNA research, DNA - First isolation of DNA, DNA - Establishing a link between heritable traits and chromosomes, DNA - Discovery of the structure of DNA

Read more here: » DNA: Encyclopedia II - DNA - Overview

There are many ways to accurately manipulate single molecules. Prominent among these are optical or magnetic tweezers and atomic-force-microscope (AFM) cantilevers. In all of these techniques, a biomolecule, such as protein or DNA, or some other biopolymer has one end bound to a surface and the other to a force sensor. The force sensor is usually a micrometre-sized bead or a cantilever, whose displacement can be measured to determine the force. Fo ...

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Force spectroscopy, Force spectroscopy - Experimental techniques, Force spectroscopy - Atomic force microscope cantilevers, Force spectroscopy - Optical tweezers, Force spectroscopy - Applications

Read more here: » Force spectroscopy: Encyclopedia II - Force spectroscopy - Experimental techniques

Raman spectroscopy is commonly used in chemistry, since vibrational information is very specific for the chemical bonds in molecules. It therefore provides a fingerprint by which the molecule can be identified. The fingerprint region of organic molecules is in the range 500-2000 cm-1. Another way that the technique is used is to study changes in chemical bonding, e.g. when a substrate is added to an enzyme. Raman gas analyzers have many practical applications, for instance they are used in medicine for real-time monitoring of anaes ...

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Raman spectroscopy, Raman spectroscopy - Basic theory, Raman spectroscopy - Applications, Raman spectroscopy - Raman microspectroscopy, Raman spectroscopy - History, Raman spectroscopy - Other Types

Read more here: » Raman spectroscopy: Encyclopedia II - Raman spectroscopy - Applications

Laguerre-Gaussian modes can be created with a spiral phase plate, computer-generated holograms, Hermite-Gaussian mode conversion or a spatial light modulator. Static spiral phase plates (SPPs) are spiral-shaped pieces of crystal or plastic that are engineered specifically to the desired topological charge and incident wavelength. They are efficient, yet expensive. Adjustable SPPs can be made by moving a wedge betwe ...

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Optical vortex, Optical vortex - Properties, Optical vortex - Creation, Optical vortex - Applications

Read more here: » Optical vortex: Encyclopedia II - Optical vortex - Creation

Traditional studies in biology are conducted using statistical ensemble experiments, typically using pico- to micro-molar concentrations of macromolecules. Because the molecules that comprise living cells are so small, techniques such as PCR amplification, gel blotting, fluorescence labeling and in vivo staining are used so that experimental results are observable with an unaided eye or, at most, optical magnification. Using these techniques, biologists attempt to elucidate the complex systems of interactions that give rise to the processes ...

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Biophysics, Biophysics - Overview, Biophysics - Topics in biophysics and related fields, Biophysics - Famous biophysicists, Biophysics - Other notable biophysicists

Read more here: » Biophysics: Encyclopedia II - Biophysics - Overview

Light is made up of particles called photons and hence inherently is "grainy" (quantized); quantum optics is the study of the nature and effects of this. The first indication that light might be quantized came from Max Planck in 1899 when he correctly modelled blackbody radiation by assuming that the exchange of energy between light and matter only occurred in discrete amounts he called quanta. It was unknown whether the source of this discreteness was the matter or the light. In 1905, Albert Einstein published the theory of the photoelectri ...

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Quantum optics, Quantum optics - History of quantum optics, Quantum optics - Concepts of quantum optics

Read more here: » Quantum optics: Encyclopedia II - Quantum optics - History of quantum optics

The discovery that DNA was the carrier of genetic information was a process that required many earlier discoveries. The existence of DNA was discovered in the mid 19th century. However, it was only in the early 20th century that researchers began suggesting that it might store genetic information. This was only accepted after the structure of DNA was elucidated by Watson and Crick in their 1953 Nature publication. Watson and Crick proposed the central dogma of molecular biology in 1957, describing the process whereby proteins are produced from nucleic DNA. ...

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DNA, DNA - Overview, DNA - DNA in practice, DNA - DNA in crime, DNA - DNA in computation, DNA - Overview of molecular structure, DNA - The role of the sequence, DNA - DNA replication, DNA - Mechanical properties relevant to biology, DNA - Strands association and dissociation, DNA - Circular DNA, DNA - Great length versus tiny breadth, DNA - Entropic stretching behavior, DNA - Different helix geometries, DNA - Non-helical forms, DNA - Direction of DNA strands, DNA - Chemical nomenclature 5' and 3', DNA - Sense and antisense, DNA - Distinction between sense and antisense strands, DNA - As viewed by topologists, DNA - Single-stranded DNA ssDNA and repair of mutations, DNA - The history of DNA research, DNA - First isolation of DNA, DNA - Establishing a link between heritable traits and chromosomes, DNA - Discovery of the structure of DNA, DNA - Bibliography

Read more here: » DNA: Encyclopedia II - DNA - The history of DNA research

The asymmetric shape and linkage of nucleotides means that a DNA strand always has a discernible orientation or directionality. Because of this directionality, close inspection of a double helix reveals that nucleotides are heading one way along one strand (the "ascending strand"), and the other way along the other strand (the "descending strand"). This arrangement of the strands is called antiparallel. < ...

See also:

DNA, DNA - Overview, DNA - DNA pairing, DNA - DNA in practice, DNA - DNA in crime, DNA - DNA in computation, DNA - Overview of molecular structure, DNA - The role of the sequence, DNA - DNA replication, DNA - Mechanical properties relevant to biology, DNA - Strands association and dissociation, DNA - Circular DNA, DNA - Great length versus tiny breadth, DNA - Entropic stretching behavior, DNA - Different helix geometries, DNA - Non-helical forms, DNA - Direction of DNA strands, DNA - Chemical nomenclature 5' and 3', DNA - Sense and antisense, DNA - Distinction between sense and antisense strands, DNA - As viewed by topologists, DNA - Single-stranded DNA ssDNA and repair of mutations, DNA - The history of DNA research, DNA - First isolation of DNA, DNA - Establishing a link between heritable traits and chromosomes, DNA - Discovery of the structure of DNA

Read more here: » DNA: Encyclopedia II - DNA - Direction of DNA strands

Main article: Mechanical properties of DNA. DNA - Strands association and dissociation. The hydrogen bonds between the strands of the double helix are weak enough that they can be easily separated by enzymes. Enzymes known as helicases unwind the strands to facilitate the advance of sequence-reading enzymes such as DNA polymerase. The unwinding requires that helicases chemically cleave the phosphate backbone of one of the strands so that it can swivel around the other. The strands can also be separa ...

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DNA, DNA - Overview, DNA - DNA pairing, DNA - DNA in practice, DNA - DNA in crime, DNA - DNA in computation, DNA - Overview of molecular structure, DNA - The role of the sequence, DNA - DNA replication, DNA - Mechanical properties relevant to biology, DNA - Strands association and dissociation, DNA - Circular DNA, DNA - Great length versus tiny breadth, DNA - Entropic stretching behavior, DNA - Different helix geometries, DNA - Non-helical forms, DNA - Direction of DNA strands, DNA - Chemical nomenclature 5' and 3', DNA - Sense and antisense, DNA - Distinction between sense and antisense strands, DNA - As viewed by topologists, DNA - Single-stranded DNA ssDNA and repair of mutations, DNA - The history of DNA research, DNA - First isolation of DNA, DNA - Establishing a link between heritable traits and chromosomes, DNA - Discovery of the structure of DNA

Read more here: » DNA: Encyclopedia II - DNA - Mechanical properties relevant to biology

Main article: DNA replication DNA replication or DNA synthesis is the process of copying the double-stranded DNA prior to cell division. The two resulting double strands are generally almost perfectly identical, but occasionally errors in replication or exposure to chemicals, or radiation can result in a less than perfect copy (see mutation), and each of them consists of one original and one newly synthesized strand. This is called semiconservative replication. The process of replication consists of three steps: initiation, ...

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DNA, DNA - Overview, DNA - DNA in practice, DNA - DNA in crime, DNA - DNA in computation, DNA - Overview of molecular structure, DNA - The role of the sequence, DNA - DNA replication, DNA - Mechanical properties relevant to biology, DNA - Strands association and dissociation, DNA - Circular DNA, DNA - Great length versus tiny breadth, DNA - Entropic stretching behavior, DNA - Different helix geometries, DNA - Non-helical forms, DNA - Direction of DNA strands, DNA - Chemical nomenclature 5' and 3', DNA - Sense and antisense, DNA - Distinction between sense and antisense strands, DNA - As viewed by topologists, DNA - Single-stranded DNA ssDNA and repair of mutations, DNA - The history of DNA research, DNA - First isolation of DNA, DNA - Establishing a link between heritable traits and chromosomes, DNA - Discovery of the structure of DNA, DNA - Bibliography

Read more here: » DNA: Encyclopedia II - DNA - DNA replication

A Laguerre-Gaussian (LG) laser beam is a well-defined optical vortex, which has the form r | m | eimφe − r * r. It is a solution to Maxwell's equations consisting of the Laguerre polynomials. There are higher-order LG beams that resemble bull's-eye patterns, described by the index p. Such beams where p is not zero have singularit ...

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Optical vortex, Optical vortex - Properties, Optical vortex - Creation, Optical vortex - Applications

Read more here: » Optical vortex: Encyclopedia II - Optical vortex - Properties

The asymmetric shape and linkage of nucleotides means that a DNA strand always has a discernible orientation or directionality. Because of this directionality, close inspection of a double helix reveals that nucleotides are heading one way along one strand (the "ascending strand"), and the other way along the other strand (the "descending strand"). This arrangement of the strands is called antiparallel. < ...

See also:

DNA, DNA - Overview, DNA - DNA in practice, DNA - DNA in crime, DNA - DNA in computation, DNA - Overview of molecular structure, DNA - The role of the sequence, DNA - DNA replication, DNA - Mechanical properties relevant to biology, DNA - Strands association and dissociation, DNA - Circular DNA, DNA - Great length versus tiny breadth, DNA - Entropic stretching behavior, DNA - Different helix geometries, DNA - Non-helical forms, DNA - Direction of DNA strands, DNA - Chemical nomenclature 5' and 3', DNA - Sense and antisense, DNA - Distinction between sense and antisense strands, DNA - As viewed by topologists, DNA - Single-stranded DNA ssDNA and repair of mutations, DNA - The history of DNA research, DNA - First isolation of DNA, DNA - Establishing a link between heritable traits and chromosomes, DNA - Discovery of the structure of DNA, DNA - Bibliography

Read more here: » DNA: Encyclopedia II - DNA - Direction of DNA strands