共查询到20条相似文献，搜索用时 15 毫秒
1.
A.G. MORALES E.S. STEMPINSKI X. XIAO A. PATEL A. PANNA K.N. OLIVIER P.J. MCSHANE C. ROBINSON A.J. GEORGE D.R. DONAHUE P. CHEN H. WEN 《Journal of microscopy》2016,263(1):113-117
Transmission electron microscopy (TEM) provides sub‐nanometre‐scale details in volumetric samples. Samples such as pathology tissue specimens are often stained with a metal element to enhance contrast, which makes them opaque to optical microscopes. As a result, it can be a lengthy procedure to find the region of interest inside a sample through sectioning. We describe micro‐CT scouting for TEM that allows noninvasive identification of regions of interest within a block sample to guide the sectioning step. In a tissue pathology study, a bench‐top micro‐CT scanner with 10 μm resolution was used to determine the location of patches of the mucous membrane in osmium‐stained human nasal scraping samples. Once the regions of interest were located, the sample block was sectioned to expose that location, followed by ultra‐thin sectioning and TEM to inspect the internal structure of the cilia of the membrane epithelial cells with nanometre resolution. This method substantially reduced the time and labour of the search process from typically 20 sections for light microscopy to three sections with no added sample preparation. 相似文献
2.
Tanaka K Morimoto Y Toiyama Y Okugawa Y Inoue Y Uchida K Kimura K Mizoguchi A Kusunoki M 《Microscopy research and technique》2012,75(3):307-315
A major challenge of cancer biology is to visualize the dynamics of the metastatic process in secondary organs at high optical resolution in vivo real-time. Here, we presented intravital, dual-colored imaging of liver metastasis formation from a single cancer cell to metastatic colonies in the living liver of living mice using two photon laser scanning microscopy (TPLSM). Red fluorescent protein expressing murine (SL4) or human (HT29) colorectal cancer cell lines were inoculated to the spleen of green fluorescent protein expressing mice. Intravital TPLSM was performed by exteriorizing and fixing the liver lobe of living mice. This was repeated several times for the long-term imaging of the same mouse. Viable cancer cells in the living liver of living mice were visualized intravitally at a magnification of over 600×. Single cancer cells were arrested within hepatic sinusoids 2 h after injection. Platelet aggregation surrounding a cancer cell was observed, indicating a phenomenon of tumor-cell induced platelet aggregation. Cancer cells were extravasated from hepatic sinusoids to the space of Disse. Protrusions of Kupffer cells surrounding a cancer cell were observed, indicating that Kupffer cells appear to phagocytose cancer cells. SL4 cells formed liver metastatic colonies with extensive stromal reaction. Liver metastases by HT29 cells were observed as a cluster of micrometastatic nodules. High-resolution, dual-colored, real-time visualization of cancer metastasis using intravital TLPSM can help to understand spatiotemporal tumor-host interactions during metastatic processes in the living organs of living animals. 相似文献
3.
Drilling is one of the most complex techniques for making ancient stone implement or adornment. For smaller perforations, it is very difficult to effectively observe drilling marks under microscope, SEM, or to obtain negative silicone rubber cast. In this report, a new exclusive nondestructive method was first introduced to resolve the observation difficulty. Virtual 3D reconstruction by using micro CT (μCT) was successfully applied to disclose drilling tool marks on the inner wall of one small perforation and its relative drilling technique was deduced, which implied that μCT has great potential to understand ancient stone drilling. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc. 相似文献
4.
Coleoid cephalopods (squid, cuttlefish, and octopus) have a well‐developed and complex central nervous system. Its absolute size is the largest among invertebrates, and the brain‐to‐body mass ratio is larger than that of fish and reptiles and equivalent to that of birds and mammals. Although a number of histological studies have been conducted on the brains of cephalopods, most of them used a light microscope or an electron microscope, which show the microstructure of the brain, but often cannot image the whole brain instantaneously. Of late, micro computed tomography (CT) has gained popularity for imaging animal brains because it allows for noninvasive three‐dimensional (3D) reconstruction and preprocessing that are not cumbersome. To perform micro‐CT on cephalopod brains, we first tested conditions suitable for preprocessing, paying special attention to staining conditions that would provide high contrast images. Four agents, iodine in 99.5% ethanol, iodine potassium iodide in water (IKI), phosphotungstic acid in 70% ethanol, and nonionic iodinated contrast agent in water, were tested at various concentrations and durations on brain of juvenile oval squid. To evaluate the quality of staining, we calculated the contrast ratio of the two‐dimensional (2D) images and compared 3D segmentation of the best and worst 2D images. We concluded that 3% IKI staining for 7 days was the best combination to enhance the images contrast of the oval squid brain, in which each brain lobe was clearly detected and 3D segmentation of the whole brain was possible. The wider applicability of this preprocessing method for micro‐CT of the brains of other cephalopods is discussed. 相似文献
5.
P. BLERY P. PILET A. VANDEN‐ BOSSCHE A. THERY J. GUICHEUX Y. AMOURIQ F. ESPITALIER N. MATHIEU P. WEISS 《Journal of microscopy》2016,262(1):40-49
Vascularization is essential for many tissues and is a main requisite for various tissue‐engineering strategies. Different techniques are used for highlighting vasculature, in vivo and ex vivo, in 2‐D or 3‐D including histological staining, immunohistochemistry, radiography, angiography, microscopy, computed tomography (CT) or micro‐CT, both stand‐alone and synchrotron system. Vascularization can be studied with or without a contrast agent. This paper presents the results obtained with the latest Skyscan micro‐CT (Skyscan 1272, Bruker, Belgium) following barium sulphate injection replacing the bloodstream in comparison with results obtained with a Skyscan In Vivo 1076. Different hard and soft tissues were perfused with contrast agent and were harvested. Samples were analysed using both forms of micro‐CT, and improved results were shown using this new micro‐CT. This study highlights the vasculature using micro‐CT methods. The results obtained with the Skyscan 1272 are clearly defined compared to results obtained with Skyscan 1076. In particular, this instrument highlights the high number of small vessels, which were not seen before at lower resolution. This new micro‐CT opens broader possibilities in detection and characterization of the 3‐D vascular tree to assess vascular tissue engineering strategies. 相似文献
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Early osteoporosis diagnosis is of important significance for reducing fracture risk. Image analysis provides a new perspective for noninvasive diagnosis in recent years. In this article, we propose a novel method based on machine‐learning method performed on micro‐CT images todiagnose osteoporosis. The aim of this work is to find a way to more effectively and accurately diagnose osteoporosis on which many methods have been proposed and practiced. In this method, in contrast to the previously proposed methods in which features are analyzed individually, several features are combined to build a classifier for distinguishing osteoporosis group and normal group. Twelve features consisting of two groups are involved in our research, including bone volume/total volume (BV/TV), bone surface/bone volume (BS/BV), trabecular number (Tb.N), obtained from the software of micro‐CT, and other four features from volumetric topological analysis (VTA). Support vector machine (SVM) method and k‐nearest neighbor (kNN) method are introduced to create classifiers with these features due to their excellent performances on classification. In the experiment, 200 micro‐CT images are used in which half are from osteoporosis patients and the rest are from normal people. The performance of the obtained classifiers is evaluated by precision, recall, and F‐measure. The best performance with precision of 100%, recall of 100%, and F‐measure of 100% is acquired when all the features are included. The satisfying result demonstrates that SVM and kNN are effective for diagnosing osteoporosis with micro‐CT images. Microsc. Res. Tech. 76:333–341, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
8.
Aline Almeida Neves Eduardo Coutinho Haimon Diniz Lopes Alves Joaquim Teixeira de Assis 《Microscopy research and technique》2015,78(10):865-872
Physiological oral mechanical forces may play a role on the progression of enamel carious lesions to cavitation. Thus, the aim of this study was to describe, by 3D finite element analysis, stress, and strain patterns in sound and carious enamel after a simulated occlusal load. Micro‐CT based models were created and meshed with tetrahedral elements (based on an extracted third molar), namely: a sound (ST) and a carious tooth (CT). For the CT, enamel material properties were assigned according to the micro‐CT gray values. Below the threshold corresponding to the enamel lesion (2.5 g/cm3) lower and isotropic elastic modulus was assigned (E = 18 GPa against E1 = 80 GPa, E2 = E3 = 20 GPa for sound enamel). Both models were imported into a FE solver where boundary conditions were assigned and a pressure load (500 MPa) was applied at the occlusal surface. A linear static analysis was performed, considering anisotropy in sound enamel. ST showed a more efficient transfer of maximum principal stress from enamel to the dentin layer, while for the CT, enamel layer was subjected to higher and concentrated loads. Maximum principal strain distributions were seen at the carious enamel surface, especially at the central fossa, correlating to the enamel cavity seen at the original micro‐CT model. It is possible to conclude that demineralized enamel compromises appropriate stress transfer from enamel to dentin, contributing to the odds of fracture and cavitation. Enamel fracture over a dentin lesion may happen as one of the normal pathways to caries progression and may act as a confounding factor during clinical diagnostic decisions. Microsc. Res. Tech. 78:865–872, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
9.
Mariana M. B. Borges Jussaro A. Duque Rafaela F. Zancan Rodrigo R. Vivan Ricardo A. Bernardes Marco A. H. Duarte 《Microscopy research and technique》2019,82(7):1057-1064
The aim of this study was to evaluate three reciprocating systems and complementary cleaning methods on filling material removal during retreatment of flattened canals. Thirty‐six mandibular incisors were prepared using rotary instruments up to size 25.08 and filled using the single‐cone technique. Subsequently, the teeth were divided into three groups (n = 12) according to retreatment procedures: Reciproc Blue (RB): 25/0.08 and 40/0.06; ProDesign R (PDR): 25/0.06 and 35/0.05; and WaveOne Gold (WOG): 25/0.07 and 35/0.06. The remaining filling volume materials were assessed by means of micro‐CT imaging before and after retreatment. After this, the specimens were subdivided into three groups according to complementary cleaning methods: XP‐Endo Shaper (30/0.01); passive ultrasonic irrigation (PUI); 60° oscillatory instrumentation with #30 H‐file, and micro‐CT scan was taken. Then, the roots were cut in half and the samples were analyzed by scanning electron microscope (SEM). The data were analyzed statistically using Kruskal–Wallis and Dunn's Multiple Comparison test with significance level of 5%. None of the reciprocating files promoted complete removal of filling material and there was no statistical difference between the groups, regardless instrument size (p > 0.05). Complementary cleaning methods increased remnant filling removal (p < 0.05). XP‐endo Shaper significantly reduced the amount of filling material in the apical and middle thirds, compared with H‐files (p < 0.05), with no difference with PUI. In the SEM, there was no statistical difference among the instruments (p > 0.05). The reciprocating systems showed similar effectiveness in removing root filling material. Complementary cleaning method with the XP‐Shaper enhanced filling material removal. 相似文献
10.
A novel algorithm has been developed and validated to isolate individual papermaking fibres in micro‐computed tomographic images of paper handsheets as a first step to characterize the structure of the paper. The three‐step fibre segmentation algorithm segments the papermaking fibres by (i) tracking the hollow inside the fibres via a modified connected component methodology, (ii) extracting the fibre walls using a distance transform and (iii) labelling the fibres through collapsed sections by a final refinement step. Furthermore, postprocessing algorithms have been developed to calculate the length and coarseness of the segmented fibres. The fibre segmentation algorithm is the first ever reported method for the automated segmentation of the tortuous three‐dimensional morphology of papermaking fibres within microstructural images of paper handsheets. The method is not limited to papermaking fibres, but can be applied to any material consisting of tortuous and hollow fibres. 相似文献
11.
KHODOR KOUBAR VIRGILE BEKAERT DAVID BRASSE PATRICE LAQUERRIERE 《Journal of microscopy》2015,258(3):241-252
Bone mineral density plays an important role in the determination of bone strength and fracture risks. Consequently, it is very important to obtain accurate bone mineral density measurements. The microcomputerized tomography system provides 3D information about the architectural properties of bone. Quantitative analysis accuracy is decreased by the presence of artefacts in the reconstructed images, mainly due to beam hardening artefacts (such as cupping artefacts). In this paper, we introduced a new beam hardening correction method based on a postreconstruction technique performed with the use of off‐line water and bone linearization curves experimentally calculated aiming to take into account the nonhomogeneity in the scanned animal. In order to evaluate the mass correction rate, calibration line has been carried out to convert the reconstructed linear attenuation coefficient into bone masses. The presented correction method was then applied on a multimaterial cylindrical phantom and on mouse skeleton images. Mass correction rate up to 18% between uncorrected and corrected images were obtained as well as a remarkable improvement of a calculated mouse femur mass has been noticed. Results were also compared to those obtained when using the simple water linearization technique which does not take into account the nonhomogeneity in the object. 相似文献
12.
Zeliha Uur Ayd&#x;n Neslihan Büra Keskin Taha
zyürek 《Microscopy research and technique》2019,82(6):856-860
The purpose of this study was to evaluate and compare the effect of Reciproc Blue (RPCB), XP‐endo Shaper (XPS), and WaveOne Gold (WOG) single‐files on dentinal microcrack formation using micro‐computed tomography (micro‐CT). Twenty‐four mesial roots (24 mesio‐buccal and 24 mesio‐lingual canals) of mandibular molar teeth were prepared using RPCB, XPS, and WOG files (n = 8/each group). The samples were scanned with micro‐CT in the pre‐ and post‐preparation. Then, before preparation and after preparation cross‐sectional images of the teeth were evaluated to detect the presence of microcracks. For each group, the number of microcracks was calculated as a percentage rate. The data were statistically analyzed using McNemar at 5% significance level (p < .05). Dentinal microcracks were observed in 25.99% (2,103 of 7,813), 31.99% (2,482 of 7,758), and 36.66% (2,836 of 7,731) of cross‐sectional images of the XPS, WOG, and RPCB groups, respectively. In all the groups, all the dentinal microcracks seen in the post‐treatment cross‐sectional images were present in the corresponding pre‐treatment images. Within the limitations of this study, the XPS, WOG, and RPCB files did not cause new dentinal microcrack formation or propagation of existing dentinal microcracks. 相似文献
13.
Aline A. Neves Roseane A. Lourenço Haimon D. Alves Ricardo T. Lopes Laura G. Primo 《Scanning》2015,37(4):258-264
14.
Erika Thuanne Gonçalves De Souza Michele Dias Nunes Tameirão Juliana Marins Roter Joaquim Teixeira De Assis Aline De Almeida Neves Gustavo André De‐Deus 《Microscopy research and technique》2013,76(10):1093-1098
The aim of the this study was to quantitatively evaluate in three‐dimensional (3D), the porosity degree of three improved silicate‐based endodontic repair cements (iRoot BP Plus®, Biodentine®, and Ceramicrete) compared to a gold‐standard calcium silicate bioactive cement (Pro Root® MTA). From each tested cement, four samples were prepared by a single operator following the manufacturer's instructions in terms of proportion, time, and mixing method, using cylindrical plastic split‐ring moulds. The moulds were lubricated and the mixed cements were inserted with the aid of a cement spatula. The samples were scanned using a compact micro‐CT device (Skyscan 1174, Bruker micro‐CT, Kontich, Belgium) and the projection images were reconstructed into cross‐sectional slices (NRecon v.1.6.9, Bruker micro‐CT). From the stack of images, 3D models were rendered and the porosity parameters of each tested material were obtained after threshold definition by comparison with standard porosity values of Biodentine®. No statistically significant differences in the porosity parameters among the different materials were seen. Regarding total porosity, iRoot BP Plus® showed a higher percentage of total porosity (9.58%), followed by Biodentine® (7.09%), Pro Root® MTA (6.63%), and Ceramicrete (5.91%). Regarding closed porosity, Biodentine® presented a slight increase in these numbers compared to the other sealers. No significant difference in porosity between iRoot BP Plus®, Biodentine®, and Ceramicrete were seen. In addition, no significant difference in porosity between the new calcium silicate‐containing repair cements and the gold‐standard MTA were found. Microsc. Res. Tech., 76:1093–1098, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
15.
Draenert ME Draenert AI Forriol F Cerler M Kunzelmann KH Hickel R Draenert K 《Microscopy research and technique》2012,75(4):416-424
An experimental approach was performed on 20 giant rabbits to establish the possibilities and limitations of μ-CT for routine processing of nondemineralized bone tissue. Hydroxyapatite (HA) or β-tricalciumphosphate (β-TCP) bead implants or a melange of both, microchambered and solid, were implanted into a standardized and precise defect in the patellar groove. The bone-healing phase was chosen for the histology considering 1 or 2 days, and 2, 3, and 6 weeks. Normal X-ray and μ-CT were applied on all specimens; five specimens in the 6-week stage were additionally processed according to the full range of conventional nondemineralized bone processing methods. μ-CT increased the possibilities of nondemineralized histology with respect to bone morphometry and a complete sequence of sections, thus providing a complete analysis of the bone response. μ-CT was limited in differentiating bone quality, cell analyses, and mineralization stages. The investigation based on normal X-rays is limited to defining integration and excluding the fibrous and bony encapsulation of loose implants. μ-CT allows a 3D evaluation of newly formed bone which is clearly marked against the ceramic implant. It does not allow, however, for the differentiation between woven and lamellar bone, the presentation of the canalicular lacunar system, or on the cell level, revealing canaliculi or details of the mineralization process which can be documented by high-resolution microradiography. Titer dynamics of bone formation remains the domain of polychromatic sequential labeling. The complete sequence of μ-CT slices enhances the possibilities for routine histology, tremendously allowing to the focus on detail histology to topographically well-defined cuts, thus providing more precise conclusions which take into consideration the whole implant. 相似文献
16.
The study of digital rock physics has seen significant advances due to the development of X‐ray micro computed tomography scanning devices. One of the advantages of using such a device is that the pore structure of rock can be mapped down to the micrometre level in three dimensions. However, in providing such high‐resolution images (low voxel size), the resulting file sizes are necessarily large (of the order of gigabytes). Lower image resolution (high voxel size) produces smaller file sizes (of the order of hundreds of megabytes), but risks losing significant details. This study describes the effect of the image resolution obtained by means of hardware‐based and software‐based approach. Four samples of porous rock were scanned using a SkyScan 1173 High Energy Micro‐CT. We found that acquisition using increased pixel binning of the camera (hardware‐based resizing) significantly affects the calculated physical properties of the samples. By contrast, voxel resizing by means of a software‐based approach during the reconstruction process yielded less effect on the porosity and specific surface area of the samples. However, the decreasing resolution of the image obtained by both the hardware‐based and the software‐based approaches affects the permeability significantly. We conclude that simulating fluid flow through the pore space using the Lattice Boltzmann method to calculate the permeability has a significant dependency on the image resolution. 相似文献
17.
Girkin JM Gu E Griffin C Choi HW Dawson MD McConnell G 《Microscopy research and technique》2004,64(4):293-296
We report on the application of confocal and multiphoton microscopic techniques for the evaluation of the latest generation of micro optical components. The optical emitting characteristics of arrays of matrix addressable GaN micrometer-sized light emitting diodes (micro-LEDs) have been measured using a commercial confocal microscope utilising the LEDs' own emission along with reflection confocal microscopy to determine the surface structure. Multiphoton induced luminescence from the 10-20-micron diameter emitters has also been used to examine the structure of the device and we compare this with electrically induced emission. In related work, the optical properties of micro lens arrays (10-100-micron diameter) fabricated in SiC, Sapphire, and Diamond have been determined using transmission confocal microscopy. Such optical microscopy techniques offer a simple, non-destructive method to determine the structure and performance of such novel devices. 相似文献
18.
In contrast to colonoscopy biopsy, which contains several disadvantages such as bleeding, sampling error, crush artifact, and time-consuming pathological procedure, multiphoton microscopy (MPM) enables direct noninvasive visualization of tissue architecture and cell morphology in live tissues without the administration of exogenous contrast agents. We performed a proof-of-principle study to evaluate the feasibility of using MPM to make real-time noninvasive optical diagnosis of colorectal cancer by investigating 30 fresh, unfixed, and unstained full-thickness colorectal specimens. We found that MPM images demonstrated irregular tubular structures, reduced stroma, and cellular and nuclear pleomorphism in the cancerous tissues. Cancer cells, characterized by irregular size and shape, enlarged nuclei, and increased nuclear-cytoplasmic ratio, were clearly observed in MPM images, which were comparable to golden standard hematoxylin-eosin staining images. Our findings showed that MPM had the potential to make real-time noninvasive optical diagnosis of colorectal cancer. With miniaturization and integration of colonoscopy, MPM has a promising future in real-time noninvasive \"optical biopsy\" for colorectal cancer. 相似文献
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Cuttitta F Pío R Garayoa M Zudaire E Julián M Elsasser TH Montuenga LM Martínez A 《Microscopy research and technique》2002,57(2):110-119
Adrenomedullin (AM) is a pluripotent regulatory peptide initially isolated from a human pheochromocytoma (adrenal tumor) and subsequently shown to play a critical role in cancer cell division, tumor neovascularization, and circumvention of programmed cell death, thus it is an important tumor cell survival factor underlying human carcinogenesis. A variety of neural and epithelial cancers have been shown to produce abundant amounts of AM. Recent findings have implicated elevation of serum AM with the onset of malignant expression. In addition, patients with tumors producing high levels of this peptide have a poor prognostic clinical outcome. Given that most human epithelial cancers display a microenvironment of reduced oxygen tension, it is interesting to note that AM and several of its receptors are upregulated during hypoxic insult. The existence of such a regulatory pathway has been implicated as the basis for the overexpression of AM/AM-R in human malignancies, thereby generating a subsequent autocrine/paracrine growth advantage for the tumor cell. Furthermore, AM has been implicated as a potential immune suppressor substance, inhibiting macrophage function and acting as a newly identified negative regulator of the complement cascade, protective properties which may help cancer cells to circumvent immune surveillance. Hence, AM's traditional participation in normal physiology (cited elsewhere in this issue) can be extended to a primary player in human carcinogenesis and may have clinical relevance as a biological target for the intervention of tumor progression. 相似文献