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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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Ex Vivo Confocal Microscopy Of Basal Cell Carcinoma On A 3-Color Scale
摘要： Ex vivo confocal microscopy (CM) is capable of visualizing freshly excised tissue in real-time with cellular resolution without routine processing. Depending on the laser wavelength, either reflectance (RCM) or fluorescence (FCM) is utilized. Ex vivo CM is useful for the rapid evaluation of tumor margins during Mohs micrographic surgery (MMS). Initially, ex vivo RCM studies used acetic acid as contrast agent to enhance basal cell carcinoma (BCC) cell nuclei. However, thin strands of BCC were frequently missed. The use of fluorophores improves contrast, so that even small strands of BCC can be spotted in FCM mosaics. Acridine orange (AO) is the dye most widely used. AO binds specifically to DNA and emits fluorescence, so images of living cell nuclei can be enhanced and displayed as bright structures in FCM mosaics. Even though good resolution and morphological correlation are achieved with this standard technique, nowadays confocal mosaics are displayed in a grey scale format. However, dermato-pathologists are often neither familiar with nor comfortable assessing these black-and-white images. We herein report a new technique for obtaining 3-color scale confocal mosaics (3CS-FCM) with the simultaneous use of AO and ethidium bromide (EB) as fluorescent dyes. In this technique, the excised skin sample is first soaked with liquid nitrogen. The sample is then sectioned into 20-30 μm-thick slices using a cryostat and stained with the dye mixture (AO 0.1 mM + EB 0.25 mM) for about one minute. The sample is then placed in the confocal microscope plate for imaging (Nikon A1R+, NIKON CORPORATION?, Japan). The tissue is scanned simultaneously with two different wavelength lasers (405 and 488 nm) and the collected fluorescence displayed on the screen as a 3-color-scale mosaic. Around 10 to 15 minutes are required for completion of the tissue processing and for final mosaics to be developed. Unlike AO, EB binds specifically to the DNA of BCC cells that are damaged due to freezing. As a result, BCC nests are stained by EB and emit red fluorescence after laser stimulation; in contrast, the epidermis and dermis are stained by AO and emit green fluorescence. Blue color corresponds to the background tissue autofluorescence. All fluorescence is collected by the microscope displaying the final images in a 3-color scale format. AO and EB staining do not affect additional fixation or staining of the sample. Figure 1 shows completed BCC mosaics displayed with this new technique. Each color represents a different skin structure, making the mosaics easier to read. In this way, 3CS confocal mosaics are more user-friendly and can be interpreted by healthcare professionals without previous experience with FCM. Moreover, with frozen sample processing, the tissue is completely flattened and the entire sample can be displayed on the screen. These developments represent important advantages over previously described images obtained with CM. In conclusion, 3CS-FCM is an innovative technique that provides colored images, expanding significantly the applicability of FCM. Larger studies are nevertheless required to validate the technique for MMS and other applications.
关键词： fluorescence confocal microscopy,3-color scale mosaics,basal cell carcinoma,ethidium bromide,acridine orange,ex vivo confocal microscopy,Mohs micrographic surgery
更新于2025-09-04 15:30:14
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Characterization of neurite dystrophy after trauma by high speed structured illumination microscopy and lattice light sheet microscopy
摘要： Background: Unbiased screening studies have repeatedly identified actin-related proteins as one of the families of proteins most influenced by neurotrauma. Nevertheless, the status quo model of cytoskeletal reorganization after neurotrauma excludes actin and incorporates only changes in microtubules and intermediate filaments. Actin is excluded in part because it is difficult to image with conventional techniques. However, recent innovations in fluorescent microscopy provide an opportunity to image the actin cytoskeleton at super-resolution resolution in living cells. This study applied these innovations to an in vitro model of neurotrauma. New method: New methods are introduced for traumatizing neurons before imaging them with high speed structured illumination microscopy or lattice light sheet microscopy. Also, methods for analyzing structured illumination microscopy images to quantify post-traumatic neurite dystrophy are presented. Results: Human induced pluripotent stem cell-derived neurons exhibited actin organization typical of immature neurons. Neurite dystrophy increased after trauma but was not influenced by jasplakinolide treatment. The F-actin content of dystrophies varied greatly from one dystrophy to another. Comparison with existing methods: In contrast to fixation dependent methods, these methods capture the evolution of the actin cytoskeleton over time in a living cell. In contrast to prior methods based on counting dystrophies, this quantification scheme parameterizes the severity of a given dystrophy as it evolves from a local swelling to an almost-perfect spheroid that threatens to transect the neurite. Conclusions: These methods can be used to investigate genetic factors and therapeutic interventions that modulate the course of neurite dystrophy after trauma.
关键词： Traumatic brain injury,Dystrophy,Structured illumination microscopy,Human induced pluripotent stem cell derived neurons,Lattice light sheet microscopy
更新于2025-09-04 15:30:14
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Metal oxide/(oxy)hydroxide overlayers as hole collectors and oxygen evolution catalysts on water splitting photoanodes
摘要： Solar-water-splitting provides a mechanism to convert and store solar energy in the form of stable chemical bonds. Water-splitting systems often include semiconductor photoanodes, such as n-Fe2O3 and n-BiVO4, which use photogenerated holes to oxidize water. These photoanodes often exhibit improved performance when coated with metal-oxide/(oxy)hydroxide overlayers that are catalytic for the water oxidation reaction. The mechanism for this improvement, however, remains a controversial topic. This is, in part, due to a lack of experimental techniques that are able to directly track the flow of photogenerated holes in such multicomponent systems. In this Perspective we illustrate how this issue can be addressed by using a second working electrode to make direct current/voltage measurements on the catalytic overlayer during operation in a photoelectrochemical cell. We discuss examples where the second working electrode is a thin metallic film deposited on the catalyst layer, as well as where it is the tip of a conducting atomic-force-microscopy probe. In applying these techniques to multiple semiconductors (Fe2O3, BiVO4, Si) paired with various metal-(oxy)hydroxide overlayers (e.g. Ni(Fe)OxHy and CoOxHy), we found in all cases investigated that the overlayers collect photogenerated holes from the semiconductor, charging to potentials sufficient to drive water oxidation. The overlayers studied thus form charge-separating heterojunctions with the semiconductor as well as serve as water-oxidation catalysts.
关键词： solar-water-splitting,water oxidation reaction,semiconductor photoanodes,photoelectrochemical cell,metal-oxide/(oxy)hydroxide overlayers
更新于2025-09-04 15:30:14
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Bioconjugation strategy for cell surface labelling with gold nanostructures designed for highly localized pH measurement
摘要： Regulation of intracellular pH is critically important for many cellular functions. The quantification of proton extrusion in different types of cells and physiological conditions is pivotal to fully elucidate the mechanisms of pH homeostasis. Here we show the use of gold nanoparticles (AuNP) to create a high spatial resolution sensor for measuring extracellular pH in proximity of the cell membrane. We test the sensor on HepG2 liver cancer cells and MKN28 gastric cancer cells before and after inhibition of Na+/H+ exchanger. The gold surface conjugation strategy is conceived with a twofold purpose: i) to anchor the AuNP to the membrane proteins and ii) to quantify the local pH from AuNP using surface enhanced Raman spectroscopy (SERS). The nanometer size of the cell membrane anchored sensor and the use of SERS enable us to visualize highly localized variation of pH induced by H+ extrusion, which is particularly upregulated in cancer cells.
关键词： cancer cells,SERS,cell surface labelling,pH measurement,gold nanoparticles
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Polarimetric wideband directional channel measurement and analysis for outdoor small cell scenarios at 32 GHz and 39 GHz
摘要： Wideband millimeter-wave (mmWave) directional propagation measurements were conducted in the 32 GHz and 39 GHz bands in outdoor line-of-sight (LoS) small cell scenarios. The measurement provides spatial and temporal statistics that will be useful for small-cell outdoor wireless networks for future mmWave bands. Measurements were performed at two outdoor environments and repeated for all polarization combinations. Measurement results show little spread in the angular and delay domains for the LoS scenario. Moreover root-mean-squared (RMS) delay spread at different polarizations show small difference which can be due to specific scatterers in the channel.
关键词： propagation channel measurement,RMS delay spread,small-cell,full polarimetric,directional,Millimeter-Wave
更新于2025-09-04 15:30:14
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High-Speed and Uninterrupted Communication for High-Speed Trains by Ultrafast WDM Fiber-Wireless Backhaul System
摘要： We developed a high-speed and handover-free communication network for high-speed trains (HSTs) using an ultrafast and switchable wavelength-division multiplexing fiber-wireless backhaul system in the W band. We successfully transmitted approximately 20-Gb/s and 10-Gb/s signals over the in the downlink and uplink switched fiber-wireless directions, respectively. An ultrafast radio-cell switching of less than 10 μs was experimentally demonstrated in both downlink and uplink directions. Moreover, the possibility of connecting a central station to many remote radio cells was evaluated, confirming that an uninterrupted communication network up to several tens of kilometers can be achieved for HSTs. The proposed system can overcome the current challenges in mobile networks and can provide a potential solution for the provision of advanced services to users on HSTs in future 5G and beyond networks.
关键词： high-speed train,moving cell,fiber-wireless convergence,mobile backhaul,Radio-over-fiber
更新于2025-09-04 15:30:14
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Achieve Automated Organelle Biopsy on Small Single Cells Using a Cell Surgery Robotic System
摘要： Single cell surgery such as manipulation or removal of subcellular components or/and organelles from single cells is increasingly used for the study of diseases and their causes in precision medicine. This paper presents a robotic surgery system to achieve automated organelle biopsy of single cells with dimensions of less than 20 μm in diameter. The complexity of spatial detection of the organelle position is reduced by patterning the cells using a microfluidic chip device. A sliding mode nonlinear controller is developed to enable extraction of organelles, such as the mitochondria and the nucleus, from single cells with high precision. An image processing algorithm is also developed to automatically detect the position of the desired organelle. The effectiveness of the proposed robotic surgery system is demonstrated experimentally with automated extraction of mitochondria and nucleus from human acute promyelocytic leukemia cells and human fibroblast cells. Extraction is followed by biological tests to indicate the functionality of biopsied mitochondria as well as the cell viability after removal of mitochondria. The results presented here have revealed that the proposed approach of automated organelle biopsy on single small cells is feasible.
关键词： mitochondria,single cell manipulation,organelle biopsy,robotic surgery
更新于2025-09-04 15:30:14
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The Effect of PKCα on the Light Response of Rod Bipolar Cells in the Mouse Retina
摘要： PURPOSE. Protein kinase C a (PKCa) is abundantly expressed in rod bipolar cells (RBCs) in the retina, yet the physiological function of PKCa in these cells is not well understood. To elucidate the role of PKCa in visual processing in the eye, we examined the effect of genetic deletion of PKCa on the ERG and on RBC light responses in the mouse. METHODS. Immuno?uorescent labeling was performed on wild-type (WT), TRPM1 knockout, and PKCa knockout (PKC-KO) retina. Scotopic and photopic ERGs were recorded from WT and PKC-KO mice. Light responses of RBCs were measured using whole-cell recordings in retinal slices from WT and PKC-KO mice. RESULTS. Protein kinase C alpha expression in RBCs is correlated with the activity state of the cell. Rod bipolar cells dendrites are a major site of PKCa phosphorylation. Electroretinogram recordings indicated that loss of PKCa affects the scotopic b-wave, including a larger peak amplitude, longer implicit time, and broader width of the b-wave. There were no differences in the ERG a- or c-wave between PKCa KO and WT mice, indicating no measurable effect of PKCa in photoreceptors or the RPE. The photopic ERG was unaffected consistent with the lack of detectable PKCa in cone bipolar cells. Whole-cell recordings from RBCs in PKC-KO retinal slices revealed that, compared with WT, RBC light responses in the PKC-KO retina are delayed and of longer duration. CONCLUSIONS. Protein kinase C alpha plays an important modulatory role in RBCs, regulating both the peak amplitude and temporal properties of the RBC light response in the rod visual pathway.
关键词： electroretinogram,protein kinase C,b-wave,rod bipolar cell
更新于2025-09-04 15:30:14
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Frequency-Modulated Wave Dielectrophoresis of Vesicles And Cells: Periodic U-Turns at the Crossover Frequency
摘要： We have formulated the dielectrophoretic force exerted on micro/nanoparticles upon the application of frequency-modulated (FM) electric fields. By adjusting the frequency range of an FM wave to cover the crossover frequency fX in the real part of the Clausius-Mossotti factor, our theory predicts the reversal of the dielectrophoretic force each time the instantaneous frequency periodically traverses fX. In fact, we observed periodic U-turns of vesicles, leukemia cells, and red blood cells that undergo FM wave dielectrophoresis (FM-DEP). It is also suggested by our theory that the video tracking of the U-turns due to FM-DEP is available for the agile and accurate measurement of fX. The FM-DEP method requires a short duration, less than 30 s, while applying the FM wave to observe several U-turns, and the agility in measuring fX is of much use for not only salty cell suspensions but also nanoparticles because the electric-field-induced solvent flow is suppressed as much as possible. The accuracy of fX has been verified using two types of experiment. First, we measured the attractive force exerted on a single vesicle experiencing alternating-current dielectrophoresis (AC-DEP) at various frequencies of sinusoidal electric fields. The frequency dependence of the dielectrophoretic force yields fX as a characteristic frequency at which the force vanishes. Comparing the AC-DEP result of fX with that obtained from the FM-DEP method, both results of fX were found to coincide with each other. Second, we investigated the conductivity dependencies of fX for three kinds of cell by changing the surrounding electrolytes. From the experimental results, we evaluated simultaneously both of the cytoplasmic conductivities and the membrane capacitances using an elaborate theory on the single-shell model of biological cells. While the cytoplasmic conductivities, similar for these cells, were slightly lower than the range of previous reports, the membrane capacitances obtained were in good agreement with those previously reported in the literature.
关键词： Cell,Frequency-modulated wave,Crossover frequency,The Clausius-Mossotti factor,Spectroscopy,Dielectrophoresis,Vesicle
更新于2025-09-04 15:30:14
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Polarisation analysis on the LET time-of-flight spectrometer
摘要： We present a design for implementing uniaxial polarisation analysis on the LET cold neutron time-of-?ight spectrometer, installed on the second target station at ISIS. The polarised neutron beam is to be produced by a transmission-based supermirror polariser with the polarising mirrors arranged in a “double-V” formation. This will be followed by a Mezei-type precession coil spin ?ipper, selected for its small spatial requirements, as well as a permanent magnet guide ?eld to transport the beam polarisation to the sample position. The sample area will contain a set of holding ?eld coils, whose purpose is to produce a highly homogenous magnetic ?eld for the wide-angle 3He analyser cell. To facilitate fast cell changes and reduce the risk of cell failure, we intend to separate the cell and cryostat from the vacuum of the sample tank by installing both in a vessel at atmospheric pressure. When the instrument upgrade is complete, the performance of LET is expected to be commensurate with existing and planned polarised cold neutron spectrometers at other sources. Finally, we discuss the implications of performing uniaxial polarisation analysis only, and identify quasi-elastic neutron scattering (QENS) on ionic conducting materials as an interesting area to apply the technique.
关键词： cold neutron,polarisation analysis,LET spectrometer,quasi-elastic neutron scattering,supermirror polariser,Mezei-type precession coil,time-of-?ight,3He analyser cell
更新于2025-09-04 15:30:14