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Fluorescence Correlation Spectroscopy
Fluorescence correlation spectroscopy (FCS) is a statistical analysis, via time correlation, of stationary fluctuations of the fluorescence intensity. Its theoretical underpinning originated from L. Onsager's regression hypothesis. The analysis provides kinetic parameters of the physical processes underlying the fluctuations. One of the interesting applications of this is an analysis of the concentration fluctuations of fluorescent particles (molecules) in solution. In this application, the fluorescence emitted from a very tiny space in solution containing a small number of fluorescent particles (molecules) is observed. The fluorescence intensity is fluctuating due to Brownian motion of the particles. In other words, the number of the particles in the sub-space defined by the optical system is randomly changing around the average number. The analysis gives the average number of fluorescent particles and average diffusion time, when the particle is passing through the space. Eventua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after. Fluorescence has many practical applications, including mineralogy, gemology, medicine, chemical sensors (fluorescence spectroscopy), fluorescent labelling, dyes, biological detectors, cosmic-ray detection, vacu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superconducting Nanowire Single-photon Detector
The superconducting nanowire single-photon detector (SNSPD or SSPD) is a type of optical and near-infrared single-photon detector based on a current-biased superconducting nanowire. It was first developed by scientists at Moscow State Pedagogical University and at the University of Rochester in 2001. The first fully operational prototype was demonstrated in 2005 by the National Institute of Standards and Technology (Boulder), and BBN Technologies as part of the DARPA Quantum Network. As of 2021, a superconducting nanowire single-photon detector is the fastest single-photon detector (SPD) for photon counting. It is a key enabling technology for quantum optics and optical quantum technologies. SNSPDs are available with very high detection efficiency, very low dark count rate and very low timing jitter, compared to other types of single-photon detectors. As of 2021, commercial SNSPD devices are available in multichannel systems in a price range of 100,000 euros. Principle of ope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triplet State
In quantum mechanics, a triplet is a quantum state of a system with a spin of quantum number =1, such that there are three allowed values of the spin component, = −1, 0, and +1. Spin, in the context of quantum mechanics, is not a mechanical rotation but a more abstract concept that characterizes a particle's intrinsic angular momentum. It is particularly important for systems at atomic length scales, such as individual atoms, protons, or electrons. Almost all molecules encountered in daily life exist in a singlet state, but molecular oxygen is an exception. At room temperature, O2 exists in a triplet state, which can only undergo a chemical reaction by making the forbidden transition into a singlet state. This makes it kinetically nonreactive despite being thermodynamically one of the strongest oxidants. Photochemical or thermal activation can bring it into the singlet state, which makes it kinetically as well as thermodynamically a very strong oxidant. __TOC__ Two spin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexa Fluor
The Alexa Fluor family of fluorescent dyes is a series of dyes invented by Molecular Probes, now a part of Thermo Fisher Scientific, and sold under the Invitrogen brand name. Alexa Fluor dyes are frequently used as cell and tissue labels in fluorescence microscopy and cell biology. Alexa Fluor dyes can be conjugated directly to primary antibodies or to secondary antibodies to amplify signal and sensitivity or other biomolecules. The excitation and emission spectra of the Alexa Fluor series cover the visible spectrum and extend into the infrared. The individual members of the family are numbered according roughly to their excitation maxima in nanometers. History Richard and Rosaria Haugland, the founders of Molecular Probes, are well known in biology and chemistry for their research into fluorescent dyes useful in biological research applications. At the time that Molecular Probes was founded, such products were largely unavailable commercially. A number of fluorescent dyes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fractal
In mathematics, a fractal is a geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scales, as illustrated in successive magnifications of the Mandelbrot set. This exhibition of similar patterns at increasingly smaller scales is called self-similarity, also known as expanding symmetry or unfolding symmetry; if this replication is exactly the same at every scale, as in the Menger sponge, the shape is called affine self-similar. Fractal geometry lies within the mathematical branch of measure theory. One way that fractals are different from finite geometric figures is how they scale. Doubling the edge lengths of a filled polygon multiplies its area by four, which is two (the ratio of the new to the old side length) raised to the power of two (the conventional dimension of the filled polygon). Likewise, if the radius of a filled sphere i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anomalous Diffusion
Anomalous diffusion is a diffusion process with a non-linear relationship between the mean squared displacement (MSD), \langle r^(\tau )\rangle , and time. This behavior is in stark contrast to Brownian motion, the typical diffusion process described by Einstein and Smoluchowski, where the MSD is linear in time (namely, \langle r^(\tau )\rangle =2dD\tau with ''d'' being the number of dimensions and ''D'' the diffusion coefficient). Examples of anomalous diffusion in nature have been observed in biology in the cell nucleus, plasma membrane and cytoplasm. Unlike typical diffusion, anomalous diffusion is described by a power law, \langle r^(\tau )\rangle =K_\alpha\tau^\alphawhere K_\alpha is the so-called generalized diffusion coefficient and \tau is the elapsed time. In Brownian motion, α = 1. If α > 1, the process is superdiffusive. Superdiffusion can be the result of active cellular transport processes or due to jumps with a heavy-tail distribution. If α < 1, the par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mean Squared Displacement
In statistical mechanics, the mean squared displacement (MSD, also mean square displacement, average squared displacement, or mean square fluctuation) is a measure of the deviation of the position of a particle with respect to a reference position over time. It is the most common measure of the spatial extent of random motion, and can be thought of as measuring the portion of the system "explored" by the random walker. In the realm of biophysics and environmental engineering, the Mean Squared Displacement is measured over time to determine if a particle is spreading slowly due to diffusion, or if an advective force is also contributing. Another relevant concept, the variance-related diameter (VRD, which is twice the square root of MSD), is also used in studying the transportation and mixing phenomena in the realm of environmental engineering. It prominently appears in the Debye–Waller factor (describing vibrations within the solid state) and in the Langevin equation (describin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FCS Data And Fit
FCS may refer to: Education * Faith Christian School (other) * Faujdarhat Collegiate School, in Chittagong, Bangladesh * Florence Christian School in South Carolina, United States * Florida College System, in the United States * Foothills Christian Schools, in San Diego County, California, United States * Forsyth County Schools in Georgia, United States * Franklin College Switzerland, an American college in Switzerland * Friendship Christian School (other) * Friends' Central School, in Pennsylvania, United States Sports * Football Championship Subdivision, an American football classification in the NCAA in the United States for college football * Fox College Sports, an American television sport network Association football clubs * 1. FC Saarbrücken, in Germany * FC Red Bull Salzburg, in Austria * FC Schaffhausen, in Switzerland * 1. FC Schweinfurt 05, in Germany * 1. FC Slovácko, in the Czech Republic * FC South End, in Trinidad and Tobago * FC Stra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levenberg–Marquardt Algorithm
In mathematics and computing, the Levenberg–Marquardt algorithm (LMA or just LM), also known as the damped least-squares (DLS) method, is used to solve non-linear least squares problems. These minimization problems arise especially in least squares curve fitting. The LMA interpolates between the Gauss–Newton algorithm (GNA) and the method of gradient descent. The LMA is more robust than the GNA, which means that in many cases it finds a solution even if it starts very far off the final minimum. For well-behaved functions and reasonable starting parameters, the LMA tends to be slower than the GNA. LMA can also be viewed as Gauss–Newton using a trust region approach. The algorithm was first published in 1944 by Kenneth Levenberg, while working at the Frankford Army Arsenal. It was rediscovered in 1963 by Donald Marquardt, who worked as a statistician at DuPont, and independently by Girard, Wynne and Morrison. The LMA is used in many software applications for solving gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment-generating Function
In probability theory and statistics, the moment-generating function of a real-valued random variable is an alternative specification of its probability distribution. Thus, it provides the basis of an alternative route to analytical results compared with working directly with probability density functions or cumulative distribution functions. There are particularly simple results for the moment-generating functions of distributions defined by the weighted sums of random variables. However, not all random variables have moment-generating functions. As its name implies, the moment-generating function can be used to compute a distribution’s moments: the ''n''th moment about 0 is the ''n''th derivative of the moment-generating function, evaluated at 0. In addition to real-valued distributions (univariate distributions), moment-generating functions can be defined for vector- or matrix-valued random variables, and can even be extended to more general cases. The moment-generating func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Return Probability
Return may refer to: In business, economics, and finance * Return on investment (ROI), the financial gain after an expense. * Rate of return, the financial term for the profit or loss derived from an investment * Tax return, a blank document or template supplied by a government for use in the reporting of tax information * Product return, the process of bringing back merchandise to a retailer for a refund or exchange * Returns (economics), the benefit distributed to the owner of a factor of production * Abnormal return, denoting the difference in behaviour between one stock and the overall stock market * Taxes, where tax returns are forms submitted to taxation authorities In technology * Return (architecture), the receding edge of a flat face * Carriage return, a key on an alphanumeric keyboard commonly equated with the "enter" key * Return statement, a computer programming statement that ends a subroutine and resumes execution where the subroutine was called * Return code, a met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FCS Example Data 20 Point Font
FCS may refer to: Education * Faith Christian School (other) * Faujdarhat Collegiate School, in Chittagong, Bangladesh * Florence Christian School in South Carolina, United States * Florida College System, in the United States * Foothills Christian Schools, in San Diego County, California, United States * Forsyth County Schools in Georgia, United States * Franklin College Switzerland, an American college in Switzerland * Friendship Christian School (other) * Friends' Central School, in Pennsylvania, United States Sports * Football Championship Subdivision, an American football classification in the NCAA in the United States for college football * Fox College Sports, an American television sport network Association football clubs * 1. FC Saarbrücken, in Germany * FC Red Bull Salzburg, in Austria * FC Schaffhausen, in Switzerland * 1. FC Schweinfurt 05, in Germany * 1. FC Slovácko, in the Czech Republic * FC South End, in Trinidad and Tobago * FC Stra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
