激光共聚焦原位观察水泥早期水化(英文)

采用激光共聚焦显微镜对水泥早期水化过程进行原位观察,样品尺寸为35mm×25mm×5mm的水泥压实体,通过滴加水使压实体中的水泥水化。结果表明:压实体的水化对于正常水泥浆体的水化有着很好的参考作用;压实体样品与水接触8h,表面生成大量的水化产物,水化16h,大部分孔洞被水化产物填充,水化1d,水泥水化到达稳定期,微结构逐渐变密实。     

Confocal Scanning Laser Microscope Image of Gradient Structure Formed in an Acrylate Copolymer/Fluoro-copolymer Blend

Thin films of poly(2-ethylhexyl acrylate-co-acrylic acid-co-vinyl acetate)/poly(vinylidene fluoride-co-hexafluoro acetone) [P(2EHA-AA-VAc)/P(VDF-HFA)] of 30/70 (by weight) blends without and with addition of 2 wt% fine silica gel were prepared on poly(ethylene terephthalate) (PET) from 20 wt% THF solution. Gradient domain morphology formed in the 30/70 blend was observed with a confocal scanning laser microscope (CSLM). Separate domains composed of P(2EHA-AA-VAc) phase were found in P(VDF-HFA) matrix at various levels of increasing depth with increasing domain size. Thus, CSLM is quite effective in morphological observation of the gradient structure formed in polymer blends, provided the blends are transparent.     

Evaluation of the Cytotoxic Behavior of Fungal Extracellular Synthesized Ag Nanoparticles Using Confocal Laser Scanning Microscope

Silver nanoparticles have been synthesized by subjecting a reaction medium to a Fusarium oxysporum biomass at 28 °C for 96 h. The biosynthesized Ag nanoparticles were characterized on the basis of their anticipated peak at 405 nm using UV-Vis-NIR spectroscopy. Structural confirmation was evident from the characteristic X-ray diffraction (XRD) pattern, high-resolution transmission electron Microscopy (HRTEM) and the particle size analyzer. The Ag nanoparticles were of dimension 40 ± 5 nm and spherical in shape. The study mainly focused on using the confocal laser scanning microscope (CLSM) to examine the cytotoxic activities of fungal synthesized Ag nanoparticles on a human breast carcinoma cell line MCF7 cell, which featured remarkable vacuolation, thus indicating a potent cytotoxic activity.     

Confocal Scanning Laser Microscopic Study of the RDX Defect Structure in Deformed Polymer‐Bonded Explosives

The influence of an explosion‐driven deformation on the defect structure in RDX crystals embedded in a polymer‐bonded explosive was investigated by means of confocal scanning laser microscopy. The images were compared to the defect structure in the as‐received RDX grades, embedded in an epoxy resin. In this way it is possible to qualitatively analyze the changes in defect structure of the RDX crystals that were induced by the explosion‐driven deformation. For the first time, these data therefore provide experimental confirmation of how shock waves mechanically interact with energetic crystals – a topic that, up to now, was only explored by means of simulations.     

扫描隧道显微镜技术在腐蚀防护研究中的应用

简述了扫描隧道显微镜技术的发展概况，着重介绍了扫描隧道显微镜在局部腐蚀、点蚀、钝化膜形成等方面的应用。     

扫描电化学显微镜扫描图像处理的实现

针对扫描电化学显微镜扫描出来的图像除了含有噪音外,常伴有一些小的亮细节,小波阈值降噪无法消除亮细节的情况,采用数学形态学对图像进行降噪并减弱亮细节,再用小波阈值对图像进行二次降噪,并将图像转换为三维图形,有较好的图像处理效果,该功能基于Visual C 与Matlab混合编程实现,代码简单易于实现.     

Scanning Tunneling Microscopy of Cubic Silicon Carbide Surfaces

Scanning tunneling microscopy is used to study β-SiC(001) surfaces. The β-SiC(001) single crystals were epitaxially grown by a two-steep chemical vapor deposition process on Si(001) wafer substrates. The overall surface topography of β-SiC is generally much rougher than that of Si wafers. Atomically resolved images corresponding to 3 × 2 and c (2 × 2) geometries of the β-SiC(001) surface are presented. Our results agree with models constructed from Si dimers for these structures. The larger-scale images show that the surface is under compressive stress and exhibits high density of defects, e.g., antiphase boundaries (APB's), in some areas. Images with unusual superstructures are also shown.     

Scanning Tunneling Microscopy of Optical Fiber Corrosion: Surface Roughness Contribution to Zero-Stress Aging

Strength, fatigue resistance, and zero-stress aging behavior control the long-term mechanical reliability of optical fibers. Zero-stress aging refers to the loss of strength of high-strength glass fibers after exposure to some corrosive environments in the absence of stress. Understanding the effect of the chemical environment under zero stress on the subsequent fracture strength of optical fibers is important because optical fibers in service will probably encounter water and other chemical species while exposed to zero- or low-stress conditions. In this work, the strength of fibers aged under zero-stress conditions at 80°C in deionized water has been measured. Scanning tunneling microscopy was also used to measure the roughening of the fibers from corrosion at intervals during the aging. The product of the median inert strength of fibers aged for various times and the square root of the roughness depth of fibers was constant within experimental error. The results show that surface roughening contributes to zero-stress aging in silica fibers.     

高固含量SiC浆料流变性能的研究

本文研究了高固含量的SiC浆料的流变行为。研究发现,由于表面被氧化使得其等电点与SiO2接近,浆料的流变行为基本符合幂律流体,用强碱性分散剂效果好于中性分散剂。     

Confocal microscopy study of polymer microcapsules for enzyme immobilisation in paper substrates

The goal of this research is to develop the technology platform required for the production of bioactive paper based on enzymes as bioactive agents. The immobilization platform described here is based on microencapsulation, which consists in the entrapment of biomolecules in the core of hollow spheres made by a semipermeable membrane. The capsules containing the enzymes can be either deposited on paper or mixed with paper pulp to prepare a bioactive paper. The activity of encapsulated laccase was compared with that of free enzyme using its reaction with the o‐phenylenediamine (OPD) substrate. Confocal Laser Scanning Microscopy (CLSM) is used to study the location of protein in microcapsules and provides explanations for differences in activity of encapsulated laccase. The location of protein in microcapsules was determined using BSA modified with the fluorescent tag sulforhodamine. Polyethyleneimine microcapsules were modified with fluorescein isothiocyanate allowing the simultaneous identification of capsule walls and of encapsulated proteins. From CLSM analysis, proteins were found to favor the wall of the capsules because of strong ionic attraction with the charged polymer. BSA was found to some extent in the core of the capsules and encapsulation of higher loadings increased the proportion of core proteins. We will also present our results on the incorporation of microcapsules in a paper substrate. CLSM was used in this section to determine the distribution and density of tagged microcapsules in the paper substrate. The response of immobilized laccase to a common substrate will also be described. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Confocal scanning laser microscopy of polymer coatings

A new nondestructive technique, confocal scanning laser microscopy (CSLM), is described that is used to characterize the topography and morphology of polymer coatings. The topography of the coating can be determined even when the coating is completely opaque. When the coating is not completely opaque, CSLM has the distinct advantage of also being able to distinguish between the coating surface and the substrate, thus enabling coating thickness to be determined over a wide range of areas. In this study CSLM was successfully applied to poly(2-vinylpyridine) coatings formed on mild steel substrates by in situ electropolymerization. Satisfactory morphological details were obtained for areas ranging from 200 × 200 μm to 4 × 4 mm. Quantitative measurements of the coating thickness and the surface roughness distribution were also carried out. Although several other nondestructive techniques for coating morphological analyses are available, CSLM has unique advantages in being able to provide simultaneous qualitative and quantitative information on coating surfaces as well as measurements over a wide range of surface areas. A comparison of CSLM with other popularly used methods is provided and the characteristics and limitations of the various techniques are discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 149–158, 1998     

In Situ Tensile Measurements of Single Fibers by Scanning Electron Microscopy

A newly developed tensile module allows tensile experiments of single fibers to be carried out under visual observation in the scanning electron microscope. This allows correlation of measured data with observed changes in the microstructure, such as surface irregularities and crack formation. With point heating, the thermal behavior of the fibers may be studied up to 2500°C. The results are presented with tensile elongation recordings and micrograph sequences of the structural changes. Carbon fibers with and without an aluminum coating were selected as testing specimens.     

Adhesion of CPO onto high modulus TPO: Lap-shear tests in conjunction with microscopy studies of the fracture surface structure

A lap-shear test was employed to investigate the failure mechanism of a chlorinated polyolefin (CPO) coating on a high-modulus thermoplastic olefin (TPO) substrate fabricated as a blend of a highly crystalline Ziegler-Natta isotactic polypropylene (iPP) and a crystalline metallocene poly(ethylene-butene) (9 wt% butene, EB9) impact modifier. The CPO was a chlorinated polypropylene containing 20 wt% Cl. The results showed that the fracture strength increased with increasing EB9 content in TPO blends. They also showed that the presence of xylene vapor during the bake step improved the adhesion between CPO and iPP itself (by 40%), but had a much smaller effect for the TPOs. Optical and transmission electronic microscopy images revealed a well-defined skin layer approximately 230 μm thick at the mold surface of the injection molded substrates. For the 25 wt% EB9 blend (TPO₂₅), this skin layer consists of thin fibers of EB trapped in a transcrystalline iPP matrix, with crystalline lamellae propagating from the matrix across the EB9 domains. Laser scanning confocal fluorescence microscopy (LCFM) and scanning electron microscopy images of iPP/CPO/iPP samples indicate that failure occurred close to the interface between the CPO and the iPP substrate, and, during fracture, the CPO layer maintained its original thickness. For the TPO/CPO/TPO sandwich samples, the fracture surfaces themselves were much rougher than that between CPO and iPP. Substantial deformation of the CPO layer was seen in the fractured samples, and failure was due primarily to cohesive fracture of the CPO in the region adjacent to the TPO substrate. From the perspective of newly introduced environmental regulations restricting aromatic hydrocarbons in automotive coatings, the most important result was the strong adhesion between CPO and TPO₂₅, with little difference between the samples exposed to xylene vapor and those not exposed to xylene.     

Imaging the Kidney with an Unconventional Scanning Electron Microscopy Technique: Analysis of the Subpodocyte Space in Diabetic Mice

Transmission electron microscopy (TEM) remains the gold standard for renal histopathological diagnoses, given its higher resolving power, compared with light microscopy. However, it imposes several limitations on pathologists, including longer sample preparation time and a small observation area. To overcome these, we introduced a scanning electron microscopy (SEM) technique for imaging resin-embedded semi-thin sections of renal tissue. We developed a rapid tissue preparation protocol for experimental models and human biopsies which, alongside SEM digital imaging acquisition of secondary electrons (SE–SEM), enables fast electron microscopy examination, with a resolution similar to that achieved by TEM. We used this unconventional SEM imaging approach to investigate the subpodocyte space (SPS) in BTBR ob/ob mice with type 2 diabetes. Analysis of semi-thin sections with secondary electrons revealed that the SPS had expanded in volume and covered large areas of the glomerular basement membrane, forming wide spaces between the podocyte body and the underlying filtering membrane. Our results show that SE–SEM is a valuable tool for imaging the kidney at the ultrastructural level, filling the magnification gap between light microscopy and TEM, and reveal that in diabetic mice, the SPS is larger than in normal controls, which is associated with podocyte damage and impaired kidney function.     

Confocal Fluorescence Microscopy Investigation for the Existence of Subdomains within Protein Storage Vacuoles in Soybean Cotyledons

In legumes, the seed storage proteins accumulate within specialized organelles called protein storage vacuoles (PSVs). In several plant species, PSVs are differentiated into subdomains that accumulate different kinds of proteins. Even though the existence of subdomains is common in cereals and legumes, it has not been reported in soybean PSVs. The two most abundant seed proteins of soybean, 7S and 11S globulins, have different temporal accumulation patterns and exhibit considerable solubility differences that could result in differential accretion of these proteins within the PSVs. Here, we employed confocal fluorescent microscopy to examine the presence or absence of subdomains within the soybean PSVs. Eosin-stained sections of FAA-fixed paraffin embedded soybean seeds, when viewed by confocal fluorescence microscopy, revealed the presence of intricate subdomains within the PSVs. However, fluorescence immunolabeling studies demonstrated that the 7S and 11S globulins were evenly distributed within the PSVs and failed to corroborate the existence of subdomains within the PSVs. Similarly, confocal scanning microscopy examination of free-hand, vibratome and cryostat sections also failed to demonstrate the existence of subdomains within PSVs. The subdomains, which were prominently seen in PSVs of FAA-fixed soybean seeds, were not observed when the seeds were fixed either in glutaraldehyde/paraformaldehyde or glutaraldehyde. Our studies demonstrate that the apparent subdomains observed in FAA-fixed seeds may be a fixation artifact.     

扫描探针显微镜在炭黑/苯乙烯-丁二烯-苯乙烯嵌段共聚物结合橡胶微观结构研究中的应用

利用扫描探针显微镜(SPM)的DFM模式观察苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)和炭黑/SBS混合物的微观形貌。结果表明:不同浓度的SBS溶液的微观形貌差异较大;炭黑/SBS混合物的分离物成"手镯"环状结构,尺寸为100nm左右,与炭黑相连物质的长度为200～300nm,横向直径约为100nm,与SBS单体的尺寸吻合,可初步判定该结构为炭黑/SBS结合橡胶。     

Confocal imaging of chromatographic fouling under flow conditions

BACKGROUND: The fouling impact of selected fouling species was assessed by utilising confocal scanning laser microscopy (CSLM) to image a packed chromatographic bed during operation. A custom‐made flow cell was packed with Q Sepharose FF and loaded with partially clarified E. coli homogenate. Selective, multicoloured fluorescent dyes were used to label a bovine serum albumin (BSA) test protein (Cy5.5), dsDNA (PicoGreen) and host cell proteins (HCPs) (Cy3). The fouling caused by the various fluorescently labelled components was visualised as a result of the fluorescence emitted by the PicoGreen‐labelled dsDNA and the Cy3‐labelled protein in the foulant stream, and by testing the adsorptive capacity of a test protein (BSA) onto the resin prior to and post‐fouling as well as following the application of a common CIP procedure. RESULTS: Values for the effective diffusivity of BSA (D_e) were derived from the confocal images and the fouling impact was assessed by comparing D_e values obtained from different fouling scenarios. Under the most extreme conditions examined, fouling caused a 20% reduction in capacity compared to a fresh bed. BSA diffusivity did not appear to be affected by the fouling conditions studied. Sequential CIP using 15 CVs of 1 mol L^?1 NaCl then 15 CVs of 1 mol L^?1 NaOH was shown to be effective in removing nucleic acids and HCPs. Subsequent BSA adsorption showed that the CIP regime successfully restored the column capacity to its original value. In contrast, 15 CVs of 1 mol L^?1 NaCl were ineffective in removing dsDNA but substantially removed HCPs. CONCLUSION: CSLM was demonstrated to be a useful tool for visualising fouling mechanisms. Comparing the results obtained by this technique using different modes of chromatographic operation provided insights into the fouling characteristics of finite baths versus packed beds. Copyright © 2007 Society of Chemical Industry     

Understanding the Behaviour of Human Cell Types under Simulated Microgravity Conditions: The Case of Erythrocytes

Erythrocytes are highly specialized cells in human body, and their main function is to ensure the gas exchanges, O₂ and CO₂, within the body. The exposure to microgravity environment leads to several health risks such as those affecting red blood cells. In this work, we investigated the changes that occur in the structure and function of red blood cells under simulated microgravity, compared to terrestrial conditions, at different time points using biochemical and biophysical techniques. Erythrocytes exposed to simulated microgravity showed morphological changes, a constant increase in reactive oxygen species (ROS), a significant reduction in total antioxidant capacity (TAC), a remarkable and constant decrease in total glutathione (GSH) concentration, and an augmentation in malondialdehyde (MDA) at increasing times. Moreover, experiments were performed to evaluate the lipid profile of erythrocyte membranes which showed an upregulation in the following membrane phosphocholines (PC): PC16:0_16:0, PC 33:5, PC18:2_18:2, PC 15:1_20:4 and SM d42:1. Thus, remarkable changes in erythrocyte cytoskeletal architecture and membrane stiffness due to oxidative damage have been found under microgravity conditions, in addition to factors that contribute to the plasticity of the red blood cells (RBCs) including shape, size, cell viscosity and membrane rigidity. This study represents our first investigation into the effects of microgravity on erythrocytes and will be followed by other experiments towards understanding the behaviour of different human cell types in microgravity.