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过滤筛选
- 2018
- electromagnetic pulse
- cell proliferation
- cell membrane permeability
- cell response to electromagnetic stress
- apoptosis
- cancer therapy
- necrosis
- Intelligent Medical Engineering
- V.N. Karazin Kharkiv National University
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Fluorescence Imaging for Ultrafiltration of Individual Nanoparticles from a Colloidal Solution in Track Membranes
摘要： We have used ? uorescence nanoscopy for direct imaging of adsorption of individual colloidal quantum dots of diameter ~10 nm (spherical core/shell CdSeS/ZnS semiconductor nanocrystals, functionalized by organic oleic acid ligands) in nanopores of a nuclear ? lter (a polypropylene track membrane with pores of diameter ~500 nm). We have shown that when a colloidal toluene solution passes through the pores of the membrane, the nanoparticles are completely retained at a depth of 10 μm.
关键词： nanopore,single-photon source,CdSe,membrane,nanoscopy,entangled-photon source,quantum dot,colloidal solution,microscopy,nanoparticles,ultra? ltration,oleic acid,nuclear ? lter,luminescence,polymer
更新于2025-09-23 15:21:21
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[Lecture Notes in Computer Science] Intelligence Science and Big Data Engineering Volume 11266 (8th International Conference, IScIDE 2018, Lanzhou, China, August 18–19, 2018, Revised Selected Papers) || An Improved Spectral Clustering Algorithm Based on Dynamic Tissue-Like Membrane System
摘要： With vast amount of data generated, it is becoming a main aspect to mine useful information from such data. Clustering research is an important task of data mining. Traditional clustering algorithms such as K-means algorithm are too old to propose high-dimensional data, so an ef?cient clustering algorithm, spectral clustering is generated. In recent years, more and more scholars has been ?rmly committing to studying spectral clustering algorithm for its solid theoretical foundation and excellent clustering results. In this paper we propose an improved spectral clustering algorithm based on Dynamic Tissue-like P System abbreviated as ISC-DTP. ISC-DTP algorithm takes use of the advantages of maximal parallelism in tissue-like membrane system. Experiment is conducted on an arti?cial data set and four UCI data sets. And we compare the ISC-DTP algorithm with original spectral clustering algorithm and K-means algorithm. The experiments demonstrate the effectiveness and robustness of the proposed algorithm.
关键词： Spectral clustering algorithm,Tissue-like membrane system,Data mining,ISC-DTP algorithm
更新于2025-09-23 15:21:21
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Gramicidin Lateral Distribution in Phospholipid Membranes: Fluorescence Phasor Plots and Statistical Mechanical Model
摘要： When using small mole fraction increments to study gramicidins in phospholipid membranes, we found that the phasor dots of intrinsic ?uorescence of gramicidin D and gramicidin A in dimyristoyl-sn-glycero-3-phosphocholine (DMPC) unilamellar and multilamellar vesicles exhibit a biphasic change with peptide content at 0.143 gramicidin mole fraction. To understand this phenomenon, we developed a statistical mechanical model of gramicidin/DMPC mixtures. Our model assumes a sludge-like mixture of ?uid phase and aggregates of rigid clusters. In the ?uid phase, gramicidin monomers are randomly distributed. A rigid cluster is formed by a gramicidin dimer and DMPC molecules that are condensed to the dimer, following particular stoichiometries (critical gramicidin mole fractions, Xcr including 0.143). Rigid clusters form aggregates in which gramicidin dimers are regularly distributed, in some cases, even to superlattices. At Xcr, the size of cluster aggregates and regular distributions reach a local maximum. Before a similar model was developed for cholesterol/DMPC mixtures (Sugar and Chong (2012) J. Am. Chem. Soc. 134, 1164–1171) and here the similarities and differences are discussed between these two models.
关键词： lipid bilayers,membrane organization,gramicidins,statistical mechanics,?uorescence spectroscopy,peptide-lipid interactions
更新于2025-09-23 15:21:21
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Ancient Family of Retinal Proteins Brought to Light “Sight-Unseen”
摘要： Rhodopsins are an ancient class of light-sensing membrane proteins that bind retinylidene chromophores in order to form pigments that absorb visible light. Light absorption triggers isomerization of the chromophore, which is bound covalently within the transmembrane core of the protein, an event that drives protein conformational changes. Type-1 rhodopsins are also known as microbial rhodopsins, which include the well-known light-driven protein pump bacteriorhodopsin found in archeabacteria. Type-2 rhodopsins, or animal rhodopsins, include the sensory rhodopsins used as visual pigments found in most animals, including humans. Both Type-1 and -2 rhodopsins share a canonical seven-transmembrane helical polytopic structure with their amino terminal tails projecting to the topological outside of the cell membrane. Rhodopsins harness light energy to perform a vast array of functions, including pumping ions, gating channel activity, activating coupled enzyme systems, and transducing light sensation in vision. Pushkarev et al. have now reported the discovery of an entirely new group of microbial rhodopsins, opening up the potential for the elucidation of an extensive new class of rhodopsins that they term “heliorhodopsins.”
关键词： heliorhodopsins,retinylidene chromophores,light-sensing,membrane proteins,rhodopsins
更新于2025-09-23 15:21:21
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Controlled Peptide-Mediated Vesicle Fusion Assessed by Simultaneous Dual-Colour Time-Lapsed Fluorescence Microscopy
摘要： We have employed a model system, inspired by SnARe proteins, to facilitate membrane fusion between Giant Unilamellar Vesicles (GUVs) and Large Unilamellar Vesicles (LUVs) under physiological conditions. in this system, two synthetic lipopeptide constructs comprising the coiled-coil heterodimer-forming peptides K4, (KiAALKe)4, or e4, (eiAALeK)4, a peG spacer of variable length, and a cholesterol moiety to anchor the peptides into the liposome membrane replace the natural SnARe proteins. GUVs are functionalized with one of the lipopeptide constructs and the fusion process is triggered by adding LUVs bearing the complementary lipopeptide. Dual-colour time lapse fluorescence microscopy was used to visualize lipid- and content-mixing. Using conventional confocal microscopy, lipid mixing was observed on the lipid bilayer of individual GUVs. in addition to lipid-mixing, content-mixing assays showed a low efficiency due to clustering of K4-functionalized LUVs on the GUVs target membranes. We showed that, through the use of the non-ionic surfactant Tween 20, content-mixing between GUVs and LUVs could be improved, meaning this system has the potential to be employed for drug delivery in biological systems.
关键词： coiled-coil peptides,LUVs,drug delivery,GUVs,membrane fusion,Tween 20
更新于2025-09-23 15:21:01
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Diversity of physical properties of bacterial extracellular membrane vesicles revealed through atomic force microscopy phase imaging
摘要： Bacteria release nanometer-scale extracellular membrane vesicles (MVs) to mediate a variety of biological processes. We analyzed individual MVs under physiological conditions by phase imaging of high-speed atomic force microscopy to assess the physiological heterogeneity of MVs isolated from bacterial cultures. Phase imaging makes it possible to map the physical properties of an individual, fragile MV in an isolated MV population containing a broad variety of vesicle diameters, from 20 to 150 nm. We also developed a method for quantitatively comparing the physical properties of MVs among samples. This allowed for the comparison of the physical properties of MVs isolated from different bacterial species. We compared bacterial MVs isolated from four bacterial species and artificially synthesized liposomes. We demonstrate that each bacterial species generates physically heterogeneous types of MVs, unlike the physical homogeneity displayed by liposomes. These results indicate that the physical heterogeneity of bacterial MVs is mainly caused by compositional differences mediated through biological phenomena and could be unique to each species. We provide a new methodology using phase imaging that would pave the way for single-vesicle analysis of extracellular vesicles of a broad size range.
关键词： heterogeneity,atomic force microscopy,physical properties,phase imaging,bacterial extracellular membrane vesicles
更新于2025-09-23 15:21:01
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Continuous in situ measurement of dissolved methane in Lake Kivu using a membrane inlet laser spectrometer
摘要： We report the ?rst high-resolution continuous pro-?le of dissolved methane in the shallow water of Lake Kivu, Rwanda. The measurements were performed using an in situ dissolved gas sensor, called Sub-Ocean, based on a patented membrane-based extraction technique coupled with a highly sensitive optical spectrometer. The sensor was originally designed for ocean settings, but both the spectrometer and the extraction system were modi?ed to extend the dynamical range up to 6 orders of magnitude with respect to the original prototype (from nmol L?1 to mmol L?1 detection) to ?t the range of concentrations at Lake Kivu. The accuracy of the instrument was estimated to ±22 % (2σ ) from the standard deviation of eight pro?les at 80 m depth, corresponding to ±0.112 mbar of CH4 in water or ±160 nmol L?1 at 25 ?C and 1 atm. The instrument was able to continuously pro?le the top 150 m of the water column within only 25 min. The maximum observed mixing ratio of CH4 in the gas phase concentration was 77 %, which at 150 m depth and under thermal conditions of the lake corresponds to 3.5 mmol L?1. Deeper down, dissolved CH4 concentrations were too large for the methane absorption spectrum to be correctly retrieved. Results are in good agreement with discrete in situ measurements conducted with the commercial HydroC? sensor. This fast-pro?ling feature is highly useful for studying the transport, production and consumption of CH4 and other dissolved gases in aquatic systems. While the sensor is well adapted for investigating most environments with a concentration of CH4 up to a few millimoles per liter, in the future the spectrometer could be replaced with a less sensitive analytical technique possibly including simultaneous detection of dissolved CO2 and total dissolved gas pressure, for exploring settings with very high concentrations of CH4 such as the bottom waters of Lake Kivu.
关键词： Lake Kivu,dissolved methane,membrane inlet laser spectrometer,Sub-Ocean sensor,HydroC? sensor
更新于2025-09-23 15:21:01
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A discrete core-shell-like micro-light-emitting diode array grown on sapphire nano-membranes
摘要： A discrete core-shell-like micro-light-emitting diode (micro-LED) array was grown on a 100 nm-thick sapphire nano-membrane array without harmful plasma etching for chip singulation. Due to proper design for the sapphire nano-membrane array, an array of multi-faceted micro-LEDs with size of 4 μm × 16 μm was grown. threading dislocation density in the micro-LeD formed on sapphire nano-membrane was reduced by 59.6% due to the sapphire nano-membranes, which serve as compliant substrates, compared to GaN formed on a planar substrate. Enhancements in internal quantum efficiency by 44% and 3.3 times higher photoluminescence intensity were also observed from it. Cathodoluminescence emission at 435 nm was measured from c-plane multiple quantum wells (MQWs), whereas negligible emissions were detected from semi-polar sidewall facets. A core-shell-like MQWs were formed on all facets, hopefully lowering concentration of non-radiative surface recombination centers and reducing leakage current paths. This study provides an attractive platform for micro-LEDs by using sapphire nano-membrane.
关键词： internal quantum efficiency,photoluminescence,threading dislocation density,micro-LED,sapphire nano-membrane,core-shell-like,cathodoluminescence
更新于2025-09-23 15:21:01
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A Method of Human Eye Parameter Measurement Based on Laser Self-Mixing Interference
摘要： The eye is the most important sensory organ of the human body, and the cornea and anterior chamber are very important components In surgeries like vision correction, it is necessary to know the accurate corneal thickness and anterior chamber depth of human eyes. Their accurate measurement cannot only provide a reference for doctors, but also provide a strong guarantee of surgical results. In order to achieve high-precision measurements of human corneal thickness and anterior chamber depth, we develop an equivalent human-eye optical system and a measurement method for the thickness. This method designs an equivalent double-membrane system to simplify the physiological structure of the cornea and anterior chamber of the human eye and irradiate the double-membrane system through laser. The re?ected light returns to the laser cavity and the original light self-mixing interference, and a photodetector collects and processes the interference signals to obtain the corneal thickness and anterior chamber depth. The correctness of the theoretical calculations is veri?ed by the experimental system, and the measurement accuracy can reach the micrometer level.
关键词： self-mixing interference,anterior chamber depth,corneal thickness,confirmatory experiment,double-membrane system
更新于2025-09-23 15:21:01
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Construction of n-TiO2/p-Ag2O Junction on Carbon Fiber Cloth with Visa??NIR Photoresponse as a Filter-Membrane-Shaped Photocatalyst
摘要： The development of effective and reusable photocatalysts with broad-spectra activity has attracted attention. Herein, we have constructed n-TiO2/p-Ag2O junction on carbon fiber (CF) cloth as an efficient and recyclable photocatalyst. With CF cloth as the substrate, TiO2 nanorods (length: 1–2 μm) are prepared by a hydrothermal process, and the in-situ growth of Ag2O nanoparticles (10–20 nm) is then realized by chemical bath deposition route. The flexible CF/TiO2/Ag2O cloth (area: 4 × 4 cm2) shows a broad and strong photo-absorption (200–1000 nm). Under the illumination of visible-light (λ > 400 nm), CF/TiO2/Ag2O cloth can efficiently eliminate 99.2% rhodamine B (RhB), 99.4% acid orange 7 (AO7), 87.6% bisphenol A (BPA), and 89.5% hexavalent chromium (Cr6+) in 100 min, superior to CF/Ag2O cloth (83.5% RhB, 60.0% AO7, 31.2% BPA and 41.8% Cr6+). In particular, under the NIR-light illumination (980 nm laser), CF/TiO2/Ag2O cloth can remove 70.9% AO7 and 60.0% Cr6+ in 100 min, which are significantly higher than those by CF/Ag2O cloth (19.8% AO7 and 18.9% Cr6+). In addition, CF/TiO2/Ag2O cloth (diameter: 10 cm), as a filter-membrane, can effectively wipe off 94.4% flowing RhB solution (rate: ~ 1 L h? 1) at 6th filtering/degrading grade. Thus, CF/TiO2/Ag2O cloth can be used as a Vis–NIR-responded filter-membrane-shaped photocatalyst with high-efficiency for purifying wastewater.
关键词： n-TiO2/p-Ag2O junction,Filter-membrane,Photocatalyst,Vis-NIR photoresponse,Carbon fiber cloth
更新于2025-09-23 15:21:01