- 标题
- 摘要
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- 实验方案
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A new self-made digital slide scanner and microscope for imaging and quantification of fluorescent microspheres
摘要： Objective: A low-cost microscope slide scanner was constructed for the purpose of digital imaging of newborn piglet brain tissue and to quantify fluorescent microspheres in tissue. Methods: Using a standard digital single-lens reflex (DSLR) camera, fluorescent imaging of newborn piglet brain tissue was performed. A computer algorithm available for download was created to detect fluorescent microspheres in the brain tissue slides and to calculate regional cerebral blood flow (rCBF). The precision of the algorithm was tested by comparing with manual counting of the fluorescent microspheres. Finally, bright-field imaging was tested by adding light diffuser film. Results: Cost of the slide scanner was a fraction of the cost of a commercial slide scanner. The slide scanner was able to image a large number of tissue slides in a semiautomatic manner and provided a large field of view (FOV) of 101 mm2 combined with a resolution of 2.9 μm. The mean difference (SD) between manual and automatic counts was in absolute numbers 0.32 (1.5) microspheres ranging from -5 to 5 microspheres per slide. The relative total difference between automatic and manual counts was -3.1%. Conclusions: A slide scanner was constructed and an automatic algorithm to detect fluorescent microspheres in tissue was developed and validated and showed an acceptable difference to “gold standard” manual counting. The slide scanner can be regarded as a low-cost alternative for researchers when digital slide imaging and quantification of fluorescent microspheres are needed.
关键词： Slide scanner,Fluorescence,Bright-field,Microspheres,Microscopy,Cerebral blood flow
更新于2025-09-23 15:23:52
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Epitaxial Graphene Sensors Combined with 3D Printed Microfluidic Chip for Heavy Metals Detection
摘要： Two-dimensional materials may constitute key elements in the development of a sensing platform where extremely high sensitivity is required, since even minimal chemical interaction can generate appreciable changes in the electronic state of the material. In this work, we investigate the sensing performance of epitaxial graphene on Si-face 4H-SiC (EG/SiC) for liquid-phase detection of heavy metals (e.g., Pb). The integration of preparatory steps needed for sample conditioning is included in the sensing platform, exploiting fast prototyping using a 3D printer, which allows direct fabrication of a microfluidic chip incorporating all the features required to connect and execute the Lab-on-chip (LOC) functions. It is demonstrated that interaction of Pb2+ ions in water-based solutions with the EG enhances its conductivity exhibiting a Langmuir correlation between signal and Pb2+ concentration. Several concentrations of Pb2+ solutions ranging from 125 nM to 500 μM were analyzed showing good stability and reproducibility over time.
关键词： heavy metals detection,3D printed flow cell,reusable lab-on-chip,epitaxial graphene,high sensitivity
更新于2025-09-23 15:23:52
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Flow cytometry and micro-Raman spectroscopy: Identification of hemocyte populations in the mussel Mytilus galloprovincialis (Bivalvia: Mytilidae) from Faro Lake and Tyrrhenian Sea (Sicily, Italy)
摘要： Immunological and structural characteristics of hemocyte populations in the mussel Mytilus galloprovincialis (Bivalvia: Mytilidae), going from two different Sicilian habitats (Faro Lake and Tyrrhenian sea), was investigated by means of two different techniques (flow cytometric and micro-Raman spectroscopy analyses). For this purpose, three hundred and sixty mussels Mytilus galloprovincialis were analyzed during November 2017. They were divided into two equal groups (triplicate sample) on the basis of the site of collection (n = 60 caught in Faro Lake - group A, and n = 60 caught in Tyrrhenian Sea - group B). Some several differences between the species of Faro Lake and Tyrrhenian Sea are observed and ascribed to the disruption of immune parameters induced by the variations of some qualitative water parameters (temperature, salinity, dissolved oxygen, pH, ammonium 10, free chlorine, total chlorine, total phosphate, orthofhosphate) recorded in the two habitats. This study is relevant for monitoring the conditions of the sea and Faro Lake, which is strongly influenced by the currents of the Tyrrhenian Sea. Faro lake is well known for the cultivation of mussels and this is part of a coastal habitat of particular interest, consisted of a peculiar biocenotic complex. Further, for the first time, significant different arrangement in the mussels cell structural organization was evidenced by simply following their highly reproducible Raman biomolecular signatures.
关键词： Hemocyte,Bivalve immunology,Deep-sea,Mussel Mytilus galloprovincialis,Flow cytometry,Raman spectroscopy
更新于2025-09-23 15:23:52
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[Micro/Nano Technologies] Micro Electro Mechanical Systems Volume 2 || Micro Thermal Flow Sensor
摘要： Measurement of ?uid mechanics is very important in various ?elds, and ?ow sensors have been widely applied to execute accurate and ef?cient measurements. Compared with other sensing principle, thermal ?ow sensors are based on convective heat transfer and take merits of simple structure and easy use and thus offer a practical solution for various ?uidics applications. In this chapter, we describe mainly hot-?lm anemometer fabricated on polyimide substrate. Hot-?lm or hot-wire anemometer utilizes a thermal element that serves as both a joule heater and a temperature sensor. We introduce the principle of thermal ?ow sensing, design and fabrication of the micro hot-?lm ?ow sensor, the measurement methodology, and application cases by using the micro hot-?lm ?ow sensors.
关键词： Flow sensor,Temperature compensation,Micro anemometer,Hot ?lm,Measurement principle
更新于2025-09-23 15:23:52
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Robust Optical Flow Estimation Using Tchebichef Moment Invariant Feature
摘要： In this paper, orthogonal moment invariant-based features are used to compute 2D optical flow from sequence of images. The gray level of pixel is described in terms of its local neighborhood using Tchebichef moment invariants rather than its individual intensity value. The description is then normalized in order to make it insensitive to intensity fluctuations due to noise or other perturbations such as varying illumination conditions. The principle of conservation of moment invariance is used to derive overdetermined system of 2D motion constraint equations in local neighborhood of each pixel. The velocity field is then estimated using the least square method. Experimental results are performed on sequential video and thermal image frames under varying environmental conditions. The run time, robustness against noisy and varying illumination conditions and rotation invariance of proposed method are compared with already existing moment and non-moment-based techniques.
关键词： Tchebichef moment,Least square estimation,Moment invariant,Optical flow,Zernike moment,Velocity field
更新于2025-09-23 15:23:52
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Rational Electron Transmission Structure in an Ag <sub/>2</sub> O/TiO <sub/>2</sub> (anatase-B) System for Effective Enhancement of Visible Light Photocatalytic Activity
摘要： Efficient optical flow estimation with high accuracy is a challenging problem in computer vision. In this paper, we present a simple but efficient segmentation-based PatchMatch framework to address this issue. Specifically, it firstly generates sparse seeds without losing important motion information by oversegmentation, and then yields sparse matches by adopting a coarse-to-fine PatchMatch with sparse seeds. Such a scheme enhances the robustness of global regularization and yields better matching results compared with the existing NNF techniques while leading to a significant speed-up due to the sparsity of these seeds. Simultaneously, we introduce an extended nonlocal propagation and adaptive random search to address the basic limitation of traditional coarse-to-fine framework in handing motion details that often vanish at coarser levels. Finally, we obtain dense matches at the finest level through an efficient sparse-to-dense matching according to the cues of oversegmentation. While performing an efficient approximation for oversegmentation, the proposed algorithm runs significantly fast and are robust to large displacements while preserving important motion details. It also achieves good performance on the challenging MPI-Sintel and Kitti flow 2015 datasets.
关键词： extended nonlocal propagation,adaptive random search,Optical flow,PatchMatch,oversegmentation
更新于2025-09-23 15:23:52
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Calibration and characterization of intracellular Asante Potassium Green probes, APG-2 and APG-4
摘要： The response of fluorescent ion probes to ions is affected by intracellular environment. To properly calibrate them, intracellular and extracellular concentrations of the measured ion must be made equal. In the first, computational, part of this work, we show, using the example of potassium, that the two requirements for ion equilibration are complete dissipation of membrane potential and high membrane permeability for both potassium and sodium. In the second part, we tested the ability of various ionophores to achieve potassium equilibration in Jurkat and U937 cells and found a combination of valinomycin, nigericin, gramicidin and ouabain to be the most effective. In the third part, we applied this protocol to two potassium probes, APG-4 and APG-2. APG-4 shows good sensitivity to potassium but its fluorescence is sensitive to cell volume. Because ionophores cause cell swelling, calibration buffers had to be supplemented with 50 mM sucrose to keep cell volume constant. With these precautions taken, the average potassium concentrations in U937 and Jurkat cells were measured at 132 mM and 118 mM, respectively. The other tested probe, APG-2, is nonselective for cations; this is, however, a potentially useful property because the sum [K+] + [Na+] determines the amount of intracellular water.
关键词： Calibration,Ionophores,DiBAC4(3),Intracellular potassium,Cell volume,Valinomycin,ION potassium green,Gramicidin,Asante potassium green,Flow cytometry
更新于2025-09-23 15:23:52
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Three-dimensional reconstruction of incident shock/boundary layer interaction using background-oriented schlieren
摘要： To study the three-dimensional flow structure of an incident shock/boundary layer interaction, a M2.7 nozzle model with a ramp was tested based on the background-oriented schlieren (BOS) technique. After comparing the results of CFD, shear-sensitive liquid crystal (SSLC), and high-speed schlieren, we conclude that BOS can capture the internal structure of the flow field and that its results are consistent with those of other methods in which the relative error can be controlled to 7%. In this research, a new type of experiment with several light paths was used with BOS technology. Three-dimensional reconstruction of incident oblique shock (primarily the width of Mach stem of the shock wave) and quantitative results of the flow field can be obtained successfully, and BOS shows great potential for the measurement of flow fields.
关键词： visualization of flow fields,3D reconstruction,Background-oriented schlieren,quantitative measurement
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Saint Petersburg, Russia (2018.10.22-2018.10.23)] 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Monitoring of Flowing Media State by Refraction Phenomenon
摘要： A paper the refraction phenomenon for condition control of flowing media is considered. The peculiarity of flowing liquid condition control by displacement of the light-shadow boundary are determined. The results of experimental investigations are presented.
关键词： refraction,refractive index,full internal reflection,stream of fluid flow
更新于2025-09-23 15:23:52
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An Efficient Technique using Modified p-q Theory for Controlling Power Flow in a Single-Stage Single-Phase Grid-Connected PV System
摘要： In this paper, an efficient power conditioning unit (PCU) is presented for a single-phase grid-connected photovoltaic system (GCPVS) incorporating both maximum power-point tracking (MPPT) and current control algorithms in a single-stage. Modified p-q theory is applied to derive the reference signal for a hysteresis band current (HBC) controller so that independently the active and reactive power sharing between the photovoltaic (PV) system and the grid can be controlled. Enhanced stability during the internal dynamics, caused by the variations in PV generation and load conditions, is the prime aspect of the controller. The performance of the proposed p-q theory correlated HBC controller is evaluated against tracking of maximum PV power and compensation of load reactive power under the changeable atmospheric and load conditions, and also compared with the widely used conventional proportional resonant (PR) controller to justify superiority. Simulation and experiment are carried-out under variable weather and different load conditions to validate acceptability of the proposed control scheme.
关键词： modified p-q theory,Single-stage,hysteresis band current (HBC) controller,grid-connected photovoltaic system (GCPVS),power flow controlling
更新于2025-09-23 15:23:52