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Optical transparency and electrical conductivity of intermediate filaments in Müller cells and single-wall carbon nanotubes
摘要： Presently we investigated the electrical conductivity and optical transparency of Müller cell intermediate filaments. For comparison, the same properties were also explored in the model system of single-wall carbon nanotubes. We report the method of separation and purification of porcine (Sus scrofa domestica) intermediate filaments, extracted from the retinal Müller cells. We also report experimental and theoretical methods of measurements and calculations of the resistivity and light transmission yield by the intermediate filaments and single wall carbon nanotubes. The measured resistivity values were (4.7 ± 0.3) × 10?4 Ω?m?1?cm2 and (2.8 ± 0.2) × 10?4 Ω?m?1?cm2 at 5 °C (278 K), for the intermediate filaments and single wall carbon nanotubes, respectively, being quite close to those of typical metals. We report a method for measuring the light energy transmission by these nanostructures. We found that they efficiently transfer excitation energy along their axis, with the light reemitted at their other end. The measured yields of transferred light energy were 0.50 ± 0.03 and 0.26 ± 0.02 for intermediate filaments and single wall carbon nanotubes, respectively (λexc = 546.1 nm; T = 288 K). The reported results are novel, providing a direct confirmation of the earlier proposed quantum mechanism of light energy transport in the inverted retina of vertebrates. Our data also show that Müller cell intermediate filaments, in addition to their cytoskeletal function, are capable of providing for the light energy transfer within the inverted retina. The data obtained enable a significant progress in our understanding of the high-contrast vision of the vertebrate eyes. The most important conclusion of the current study is the discovery of light energy propagation along natural biological nanofibers (intermediate filaments). This result is completely novel and unique, being reported for the first time.
关键词： Müller cell,Intermediate filament,Porcine retina,Light transmission,Electric conductivity
更新于2025-09-10 09:29:36
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B7 liquid crystal filament growth in the presence of carbon nanotubes
摘要： Liquid crystal phases formed from bent-core mesogens have attracted much interest of the liquid crystal research community, due to the manifestation of chirality effects from achiral molecules. One of the most elusive of the bent-core phases is the B7 phase, which at its early stage often forms in a helical filament fashion. We investigate the growth of such filaments in the presence of single-walled nanotubes to elucidate possible effects on the growth dynamics and helicity of B7 helical filaments. It is found that the filament width slightly decreases in comparison to the neat B7 material, suggesting a more tightly bound structure around the nanotubes, with the nanotubes likely acting as the core of the helical filament. No effects on pitch or periodicity of the helical superstructure is observed. The filament growth velocity quickly decreases as nanotubes are added to the B7 phase, indicating that a more tightly bound structure needs a longer time of formation. An observed buckling instability is of interest as a microscopic example for the study of nonlinear dynamics theories of filaments. The present investigation is thus of general importance for nanoparticle directed growth of filaments, which has applications in biomolecular growth and high tensile strength fibres.
关键词： bent-core mesogens,nanotubes,buckling instability,B7 phase,liquid crystal,filament growth
更新于2025-09-09 09:28:46
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Gill Morphology in Two Bottom Feeder Mediterranean Sea Fishes: Grey Gurnard Fish (Eutrigla gurnardus, Linnaeus, 1758) and Striped Red Mullet Fish (Mullus barbatus surmuletus, Linnaeus, 1758) by Scanning Electron Microscopy
摘要： The purpose of the current investigation was to describe the gill morphology of two bottom feeders Mediterranean Sea fishes: Striped red mullet fish (M. surmuletus) and grey gurnard fish (E. gurnardus) that showed the same feeding habits. The gill system of the grey gurnard consisted of four pairs of gill arches while consisted of three pairs of gill arches in the striped red mullet. Our study focused on the scanning electron microscopical (SEM) features of the gills, where some differences in the gill arches and gill rakers surface in both species were observed. Our results marked that there was an interbranchial septum carrying a four transverse elevated crest in grey gurnard while in striped red mullet carrying a median longitudinal elevated crest. There are some similar structure on the gill arch of two fishes as; no angle between a ceratobranchial part and epibranchial part and also the gill arch has a region of many longitudinal microridges demarcated the region between gill rakers and gill filaments. By SEM, in striped red mullet, the smooth surface of gill arch and gill rakers was characterized by the presence of high number of taste buds. By SEM in grey gurnard, gill raker appeared as a round short projected body with high number of curved apex spines. Furthermore, in striped red mullet, gill raker appeared as short projected body with high number of rod-like spines. Gill filaments were long at middle and short at extremities of gill arch in both species.
关键词： Grey gurnard fish,Striped red mullet fish,Gill arch,Gill filament,Gill raker,Scanning electron microscopy
更新于2025-09-09 09:28:46
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Photo-induced negative differential resistance in a resistive switching memory device based on BiFeO3/ZnO heterojunctions
摘要： Photo-induced novel effect in a material with multiple physical properties has highly important potential applications in the photo-electric multifunctional electronic devices. In this work, the BiFeO3/ZnO bilayer films were sequentially prepared by magnetron sputtering method, which displays an obvious photo-modulated conversion between resistive switching (RS) memory and negative differential resistance (NDR) effect. Through theoretical analysis and simulation calculation, suggesting the NDR effect can be attributed to the inner electric field and the efficiently separated photogenerated electrons and holes under light-irradiation in the interface of the BiFeO3/ZnO p–n heterojunctions, while the RS memory behavior can be attributed to the formation of oxygen vacancies assisted Ag conductive filaments. This work opens up a new way to preparation a multifunction electronic device with photo-modulated conversion between RS memory and NDR effect for potential applications in optical electrical bifunctional devices, electronic information and optical quantum computers, and so on.
关键词： Oxygen vacancies,Conducting filament,Negative differential resistance,RRAM,Photo-induced
更新于2025-09-09 09:28:46
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Interconversion Between Bipolar and Complementary Behavior in Nanoscale Resistive Switching Devices
摘要： In the study of resistive random access memory using GeTeOx film as the switching layer, the device performed excellent property of bipolar resistive switching (BRS), which could be gradually transformed to the complementary resistive switching (CRS) by varying SET process current compliance. The conductive filament conduction mechanism of BRS could be verified by electrical characteristics and reliable data fitting. Through increasing current compliance of the SET process, CRS could be achieved due to higher activity of oxygen vacancies originated from the intensified thermal effect. This paper was beneficial to understand the switching mechanisms of BRS and CRS and provide a method to realize interconversion. Moreover, it was also a potential and promising device to be applied in the neurosynaptic biomimetic field.
关键词： interconversion,complementary resistive switching (CRS),conductive filament,GeTeOx,Bipolar resistive switching (BRS)
更新于2025-09-09 09:28:46
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[IEEE 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT) - Qingdao, China (2018.10.31-2018.11.3)] 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT) - A Study on the Voltage-Clamping caused by Dynamic Avalanche at Over-stress Turn-Off of GCTs
摘要： Dynamic avalanche is a key factor leading to the power device failure. By the device simulation, it is found that when the gate commutated thyristor (GCT) is turned off at a high supply voltage or high stray inductance, the anode-cathode voltage is clamped at certain value and a destructive stationary filament appears. Additionally, the SOA limited by the voltage clamping is depicted, which implies the shrink of the SOA with the increase of the emitter efficiency of anode. Its mechanism is explained in detail.
关键词： GCT,filament,SOA,voltage clamping,Dynamic avalanche
更新于2025-09-04 15:30:14