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Topic review
Updated time: 24 Aug 2021
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Definition: Amperometric biosensors and biofuel cells are mostly based on immobilized enzymes or living cells. Among the many oxidoreductases, glucose oxidase (GOx) is used mostly in biosensor design. The same GOx can be well applied for the development of biofuel cells and self-charging capacitors based on the operation of biofuel cells.
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Biography
Updated time: 29 Oct 2020
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Abstract: Anan Yaghmur is associate professor at the Department of Pharmacy, Faculty of Health & Medical Sciences, University of Copenhagen. He is also serving as a referee for at least 12 prominent journals including ACS NANO & ACS Applied Materials and Interfaces, Soft Matter, PLoS ONE, PCCP, Chemical Communications, Journal of Physical Chemistry B, and Langmuir. In addition to the evaluation of grant applications for scientific funding bodies. Anan Yaghmur has extensive expertise and know-how in formulation and nanostructural characterization of safe and efficient drug nanocarriers based on self-assembled lyotropic liquid crystalline systems and their dispersions (cubosomes and hexosomes).
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Topic review
Updated time: 29 Apr 2021
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Definition: We consider the time reversal T and particle-antiparticle C symmetries that, being most fundamental, can be violated at microscopic level by a weak interaction. The notable example here is from condensed matter, where strongly correlated Fermi systems like HF metals and high-Tc superconductors (or HF compounds) exhibit C and T symmetries violation due to the so-called non-Fermi liquid (NFL) behavior rather than to microscopic inter-particle interaction. When a HF compound is near the topological fermion condensation quantum phase transition (FCQPT), it exhibits the NFL properties, so that the C symmetry breaks down, making the differential tunneling conductivity to be an asymmetric function of the bias voltage V. This asymmetry does not take place in normal metals, where Landau Fermi liquid (LFL) theory holds. Under the application of magnetic field, a HF compound transits to the LFL state, and σ(V) becomes symmetric function of V. These findings are in good agreement with experimental observations. We suggest that the same topological FCQPT defines the baryon asymmetry in the Universe. Thus, the most fundamental features of the nature are defined by its topological and symmetry properties.
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Topic review
Updated time: 20 Feb 2021
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Definition: DNA double-strand breaks (DSBs) have been recognized as the most serious lesions in irradiated cells. While several biochemical pathways capable of repairing these lesions have been identified, the mechanisms by which cells select a specific pathway for activation at a given DSB site remain poorly understood. The impact of chromatin and repair foci architecture on these mechanisms can be elucidated by super-resolution microscopy in combination with mathematical approaches of topology. These aspects are discussed in relation to state of the art knowledge of ionizing radiation induced damaging of cell nuclei and DNA repair.
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Topic review
Updated time: 27 Jan 2021
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Definition: Closed timelike curves (CTCs) are space-time trajectories that return to their starting point without violating the laws of special relativity. A traveler along a CTC could journey into the future but arrive in its past, creating a possible violation of the principle of causality. Such CTCs occur in Gödel’s rotating universe and many other general relativistic solutions of classical Einstein’s field equations. The chronological protection conjecture suggests that Nature forbids this kind of situation.
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Topic review
Updated time: 15 Dec 2020
Definition: Depleted Complementary Metal-Oxide-Semiconductor (CMOS) sensors are emerging as one of the main candidate technologies for future tracking detectors in high luminosity colliders. Their capability of integrating the sensing diode into the CMOS wafer hosting the front-end electronics allows for reduced noise and higher signal sensitivity, due to the direct collection of the sensor signal by the readout electronics. They are suitable for high radiation environments due to the possibility of applying high depletion voltage and the availability of relatively high resistivity substrates. The use of a CMOS commercial fabrication process leads to their cost reduction and allows faster construction of large area detectors. In this contribution, a general perspective of the state of the art of CMOS detectors for High Energy Physics experiments is given. The main developments carried out with regard to these devices in the framework of the CERN RD50 collaboration are summarized.
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Topic review
Updated time: 01 Nov 2020
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Definition: Classical electrodynamics was introduced by James Clear Maxwell nearly 150 years ago and it is a subject that had been thoroughly explored over these years. Notwithstanding this long term scrutiny of this subject, there are hidden features in classical electrodynamics that actually heralds the emergence of Quantum electrodynamics in the future. Such examples can be found when analyzing the electromagnetic radiation generated by antennas working in both frequency and time domain and in the case of transition radiation generated by decelerating electrons. Here we discuss one such case. Consider the radiation generated by an antenna working in frequency domain. One can show that the energy dissipated as radiation within half a period of oscillation, say U, satisfies the inequalityU ≥ hf →q ≥ e whereq is the magnitude of the oscillating charge in the antenna, e is the elementary charge,f is the frequency of oscillation andh is the Planck constant. This result is derived while adhering strictly to the principles of classical electrodynamics alone. Combining this result with the concept of photons burrowed from quantum mechanics, one can derive an expression for the elementary charge as a function of other natural constants and the energy density of vacuum. The expression predicts the value of elementary charge to an accuracy higher than about 0.1%.
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Topic review
Updated time: 17 Dec 2020
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Definition: Light-emitting diodes (LEDs) based on Gallium Nitride (GaN) have been revolutionizing various applications in lighting, displays, biotechnology, and other fields. Many theoretical models have been developed for GaN-LED simulation, analysis, and design optimization, including carrier transport models, quantum well recombination models, and light extraction models. The overview below is a strongly abbreviated version of Ref. [1].
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Biography
Updated time: 10 Nov 2020
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Abstract: Gregg Jaeger is a scholar working primarily in the foundations of quantum theory, with significant contributions in the areas of the philosophy and history of science and quantum computing technology.
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Topic review
Updated time: 29 Oct 2020
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Definition: Gyrotrons are among the most powerful sources of coherent radiation that operate in CW and long pulse regimes in the sub-THz and the THz frequency ranges of the electromagnetic spectrum, i.e. between 0.3 THz and 3.0 THz (corresponding to wavelengths from 1.0 to 0.1 mm). This region, which spans between the frequency bands occupied by various electronic and photonic devices, respectively, is habitually called a THz power gap. The underlying mechanism of the operation of the gyrotron involves a formation of bunches of electrons gyrating in a helical electron beam and their synchronous interaction with a fast (i.e. having a superluminal phase velocity) electromagnetic wave, producing a bremsstrahlung radiation. In contrast to the slow-wave tubes, which utilize tiny structures with dimensions comparable to the wavelength of the radiation, the gyrotrons have a simpler resonant system (cavity resonator) with dimensions that are much greater than the wavelength. This allows much more powerful electron beams to be used and thus higher output powers to be achieved. Although in comparison with the classical microwave tubes the gyrotrons are characterized by greater volume and weight due to the presence of bulky parts (such as superconducting magnets and massive collectors where the energy of the spent electron beam is dissipated) they are much more compact and can easily be embedded in a sophisticated laboratory equipment (e.g. spectrometers, technological systems, etc.) than other devices such as free-electron lasers (FEL) and radiation sources based on electron accelerators. Nowadays, the gyrotrons are used as powerful sources of coherent radiation in the wide fields of high-power sub-THz and THz science and technologies [1][2][3].
Entry Collection : Remote Sensing Data Fusion
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