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Highly Rectifying Heterojunctions Formed by Annealed ZnO Nanorods on GaN Substrates
摘要： We study the effect of thermal annealing on the electrical properties of the nanoscale p-n heterojunctions based on single n-type ZnO nanorods on p-type GaN substrates. The ZnO nanorods are prepared by chemical bath deposition on both plain GaN substrates and on the substrates locally patterned by focused ion beam lithography. Electrical properties of single nanorod heterojunctions are measured with a nanoprobe in the vacuum chamber of a scanning electron microscope. The focused ion beam lithography provides a uniform nucleation of ZnO, which results in a uniform growth of ZnO nanorods. The specific configuration of the interface between the ZnO nanorods and GaN substrate created by the focused ion beam suppresses the surface leakage current and improves the current-voltage characteristics. Further improvement of the electrical characteristics is achieved by annealing of the structures in nitrogen, which limits the defect-mediated leakage current and increases the carrier injection efficiency.
关键词： chemical bath deposition,nanoscale heterojunctions,ZnO nanorods,nanoprobe in the scanning electron microscope,current-voltage characteristics,annealing,focused ion beam patterning
更新于2025-09-23 15:19:57
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The effect of different obturation methods on sealer penetration alongside apically separated rotary nickela??titanium instruments: A confocal laser scanning microscopy study
摘要： The effects of different obturation techniques on calcium silicate-based sealer penetration in the presence of apically separated rotary files were evaluated. Forty-eight extracted mandibular incisors were used. ProTaper F2 rotary files were separated at the apical thirds. Samples were divided into four groups (n = 12) according to obturation technique used: (a) cold lateral compaction (CLC); (b) single cone; (c) bulk-fill (BF) without a core material; and (d) thermoplastic injection (TI). Specimens were sectioned horizontally at 1 and 3 mm from the apex and studied using a confocal scanning laser microscope. The maximum tubule penetration depth and percentage of penetration were measured. Data were statistically analyzed using parametric and nonparametric tests with a significance level of 5%. Regarding penetration depth, a significant difference was found at 1 mm (p < .05), while no significant difference was found at 3 mm (p > .05). At the 3 mm level, all of the obturation techniques showed similar penetration depths. Regarding penetration percentage, the values of the CLC and TI groups were statistically less when compared with the BF group at 1 and 3 mm levels, respectively (p < .05). Under the limitations of this in vitro study, results suggest that the obturation technique may present a significant effect on sealer penetration.
关键词： sealer penetration,separated instruments,obturation technique,confocal laser scanning microscope
更新于2025-09-23 15:19:57
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A Preamplifier for a CdHgTe Photodetector
摘要： A preamplifier for operation with an HgCdTe-based nitrogen-cooled IR photodetector (600 nm–15 μ m) is described. The preamplifier operates in the photoconductivity mode. The use of modern microcircuits made it possible to increase the bandwidth of the response to 2 MHz at a noise level of 0.5 nV/Hz1/2, which is close to the fundamental limit that is specified by the resistance of the photosensitive element. The preamplifier was used in an aperture-free scanning near-field optical microscope.
关键词： HgCdTe,IR photodetector,scanning near-field optical microscope,photoconductivity,preamplifier
更新于2025-09-23 15:19:57
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A method for the statistical evaluation of the fluorescence intensity of single blinking quantum dots using a confocal fluorescence microscope
摘要： The evaluation of the fluorescence intensity of single quantum dots (QDs) using a confocal fluorescence microscope can provide an alternative approach for estimating the effects of environmental changes or surface modifications on the fluorescence intensity of single QDs. In the case of blinking QDs, irregular blinking would significantly influence the intensity evaluation results that are based on the analysis of one or a few single QDs. In this regard, statistical intensity evaluations based on a large number of single QDs would be helpful to estimate an approximate intensity value of single QDs with reduced effects of blinking on the evaluation results. Herein, we developed a convenient method to statistically evaluate the fluorescence intensity of a large number of single blinking QDs using Gaussian distribution. Based on the intensity analysis of thousands of single QDs, the fluorescence intensity of the single QDs evaluated using a confocal fluorescence microscope was approximately 4090 with little data fluctuation induced by blinking.
关键词： confocal fluorescence microscope,statistical evaluation,fluorescence intensity,single blinking quantum dots,Gaussian distribution
更新于2025-09-23 15:19:57
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The clinical and electron microscopic evaluation of the impact of pulsed dye laser techniques on solar lentigines (randomized clinical trial)
摘要： Background: Solar lentigines are skin lesions manifested by benign dark pigmentation causing a cosmetic problem in many patients. Several treatment modalities used for the management of solar lentigines. Side effects and rates of recurrence may be associated with them. Objective: Treating solar lentigines with two different techniques of pulsed dye laser and evaluation of the results both clinically and via the examination of ultrastructural changes by electron microscopy. Patients and methods: This study was conducted on twenty-two subjects with solar lentigines and having Fitzpatrick III-IV skin types, was managed by the use of pulsed dye laser after enrolling them into two groups. Group I (one stacked pulsed dye laser was used) and Group II (treated by stacked pulsed dye laser in two sessions, one month apart). At baseline and six months after treatment, two punch biopsies with a diameter of 2mm were taken from all patients. All taken biopsies were prepared for light and electron microscopic examinations. Results: Both pulsed dye laser techniques induced significant better clinical and histological outcomes. No one demonstrated any postoperative complications such as post-inflammatory hyperpigmentation and scarring. Conclusion: The two techniques of pulsed dye laser are efficient for solar lentigines treatment.
关键词： Pulsed Dye laser,ultrastuctural study,Solar lentigines,Electron Microscope
更新于2025-09-23 15:19:57
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Embryological development of the freshwater crab Esanthelphusa nani (Naiyanetr, 1984) (Brachyura: Gecarcinucidae) using confocal laser scanning microscopy
摘要： We investigated the embryological development of Esanthelphusa nani (Naiyanetr, 1984), a common rice-field crab in northern Thailand, using confocal laser scanning microscopy. The development of E. nani can be completed in eggs within 12 d resulting in a hatchling stage corresponding to the megalopa stage. Pre-organogenetic stages were characterized by a superficial cleavage, including egg cleavage, egg blastula, and egg gastrula. Organogenesis stages were identified by the appearances of appendages and was divided into egg nauplius, egg zoea, and egg megalopa. Crabs metamorphose to juveniles after hatching. By providing new comparative data, our study shed some new light on the relationship between environment, phylogeny, and development, opening a potential area of research from the perspective of ecological, evolutionary, and developmental biology.
关键词： ecological transition,confocal microscope,developmental biology
更新于2025-09-23 15:19:57
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A Beginners' Guide to Scanning Electron Microscopy || Imaging with the SEM
摘要： The scanning electron microscope is routinely used to characterize wide-ranging materials due to its ease of operation and relatively straightforward sample preparation as well as due to simple image interpretation. New users can readily obtain images after little practice. However, high-resolution microscopy and examination of “difficult” samples require experience and know-how of the principles of image formation in the SEM. This chapter describes the role of various operational parameters used during microscopy in more detail. The effect of these parameters on contrast, resolution, and depth of field depicted by images is discussed. Pros and cons of microscopy conditions that have a direct bearing on the quality of images, type of information obtained, and image interpretation are elaborated. Guidelines for operation and upkeep of the SEM instrument are also summarized in this chapter.
关键词： high-resolution microscopy,operational parameters,resolution,scanning electron microscope,SEM,image formation,contrast,microscopy conditions,image interpretation,depth of field
更新于2025-09-23 15:19:57
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Automated <i>E-FRET</i> microscope for dynamical live-cell FRET imaging
摘要： Acceptor-sensitized 3-cube fluorescence resonance energy transfer (FRET) imaging (also termed as E-FRET imaging) is a popular fluorescence intensity-based FRET quantification method. Here, an automated E-FRET microscope with user-friendly interfaces was set up for dynamical online quantitative live-cell FRET imaging. This microscope reduces the time of a quantitative E-FRET imaging from 12 to 3 seconds. After locating cells, calibration of the microscope and E-FRET imaging of the cells can be performed automatically by clicking “Capture” button on interfaces. E-FRET imaging was performed on the microscope for living cells expressing different FRET tandem constructs. Dynamical E-FRET imaging on the microscope for live cells co-expressing CFP-Bax and YFP-Bax treated by staurosporine (STS) revealed three Bax redistribution stages: Bax translocation from cytosol to mitochondria within 10 minutes, membrane insertion with conformational change on mitochondrial membrane within about 30 minutes, and subsequent oligomerization within about 10 minutes. Because of excellent user-friendly interface and stability, the automated E-FRET microscope is a convenient tool for quantitative FRET imaging of living cell.
关键词： FRET,biochemical signal transduction,system design,microscope
更新于2025-09-19 17:15:36
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Fluorescence-Guided Neurosurgery (Neuro-oncology and Cerebrovascular Applications) || 1 Current Fluorescence-Guided Neurosurgery and Moving Forward
摘要： This introductory chapter provides a current overview of fluorescence-guided neurosurgery and includes future directions. The concepts of fluorescence and fluorescence-guided surgery (FGS) are introduced. Currently used fluorescent contrast agents in patients are summarized, including 5-aminolevulinic acid (5-ALA), fluorescein, and indocyanine green. Excitation light sources are discussed for each fluorescent contrast agent. Targeted fluorophores under clinical development for FGS are also introduced. Future directions in fluorescence-guided neurosurgery including handheld devices to better detect tumor fluorescence, dual fluorophore imaging, metabolic imaging in combination with FGS, and detection of the tumor margin will be discussed.
关键词： near-infrared imaging,fluorophore,indocyanine green,fluorescence-guided neurosurgery,fluorescence,operative microscope,fluorescence-guided surgery,fluorescein sodium,5-ALA
更新于2025-09-19 17:15:36
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[IEEE 2018 11th Biomedical Engineering International Conference (BMEiCON) - Chiang Mai, Thailand (2018.11.21-2018.11.24)] 2018 11th Biomedical Engineering International Conference (BMEiCON) - Low-cost instrumentation of Automated Whole – slide Microscope for Biomedical Imaging
摘要： Microscope is one of the essential devices in medical profession. It is usually used for finding out types of abnormal cells or tissues, detecting the diseases, and defining a range treatment option for patient. Recently, there is a new technology of whole- slide imaging (WSI) which has been developed in the microscope. The technology provides the scanning of conventional glass slides to produce digital images of cumulative data. Since the WSI is a complex system and very expensive price, hence we aim to implement the prototype of a cost- effective whole – slide imaging system based on the principle of microscopic design. The implemented prototype consisting of optical and mechanical parts was developed using 3D printing. The optical system employed a 40x objective lens aligning with the digital camera for imaging the specimen on the standard slide. The mechanical system was designed for the movement of the slide in 3 dimensions controlled by stepper motors and microcontrollers based on controlling computer program. To accumulate the whole- slide image, the slide was scanned and captured in the X-Y axes and the focal (Z) axis in a sequence. The cumulative data was then analyzed and rendered the whole- slide image. The implemented device would be advantageous to cytologists and doctors for the biomedical imaging and recording numerous medical data of the patients.
关键词： Whole slide imaging,Biomedical imaging,Instrumentation,Microscope
更新于2025-09-19 17:15:36