bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanostructure-Nanomechanical Properties of Enamel Rods in Mouse Incisor
Authors: Fong Hanson , Sarikaya Mehmet , Snead Malcolm L , White Shane N
Published: July 2020

The understanding of detailed structures and properties of enamel is essentia for designing new implant materials that faithfully resemble enamel structure or to regenerate enamel through biomimetics using proteins as templates. As part of a greater effort in enamel biomimetics, this work focused on nanostructures and mechanical properties of individual enamel rods using the mause as a test animal.

A mature mouse incisor consists of two layers - dentin and enamel. In order to perform its normal masticatory function, the incisor must have sufficiently high flexural strength, toughness, and wear resistance. Enamel, which is highly mineralized (∼100%) with a knitted micro-architecture, satisfies the mechanical property requirements. It is known that elongated hydroxyapatite (HAP) crystals mineralize in bundles, i.e., enamel rods, and organize in a 3-D cross pattern. [1,2] However the organizations of HAP crystals within and between rods are not well understood.
“Special Boundaries” in Silicon Nitride With High Thermal Conductivty
Authors: Brito M E , Watari K , Hirao K , Toriyama M
Published: July 2020

Significant improvements in the fracture resistance, fracture toughness and thermal properties of silicon nitride ceramics are obtained by tailoring the microstructure. Combined use of seeding and tape casting techniques allowed the production of highly anisotropic microstructures. The seeded silicon nitrides exhibited a distinct bimodal microstructure, with large elongated β-Si3N4 grains, grown from seeds, dispersed within a fine-grained matrix. These large grains in the seeded silicon nitrides lie in the casting planes and self-align along the casting direction during tape forming process. It is here, when due to the high degree of alignment that “special boundaries” without the, otherwise, ubiquitous amorphous phase occurs. These “special” boundaries, hardly seen in three dimensionally random microstructures, are the object of the present study.

Silicon nitride with high thermal conductivity of up to 120 W/mK (ref. 3) is produced by hot-pressing at 1800 °C for 2 h. powders with the following nominal composition: α-Si3N4 ;5 wt% Y203; 5 vol.% (β-Si3N4 seeds.
Silicate Glass and Evaporation from Sapphire Surfaces
Authors: Ravishankar N , Barry Carter C
Published: July 2020

Ceramic materials are processed at high temperatures where different mechanisms of mass transport are operative. The liquid-phase sintering (LPS) process involves the formation of a silicate liquid at the sintering temperature. In this case, mass transport takes place at the solidliquid, solid-vapor and liquid-solid interfaces. The mechanism and kinetics of these processes controls the microstructure. The silicate phase, which is usually the sintering additive, may influence the evaporation from and of the ceramic. The importance of the evaporation process has been clearly brought out in previous studies on the dewetting of silicates on a ceramic substrate. The present study considers the influence of a silicate phase (celsian) on evaporation from a ceramic (sapphire) substrate.

Pulsed-laser deposition (PLD) has been used to deposit thin films (∼100 nm thick) of celsian (BaAl2Si2O8) on sapphire single-crystals of basal orientation. In the present study, the film/substrate assembly has been annealed at high temperatures (1750°C to 1850°C) in a vacuum furnace.
Combined CBED/Alchemi Analysis of Crystallography and Cation Distributions in the Transparent Conductive Oxide Cd1+XIn2-2XSnxO4
Authors: Brewer LN , Kammler DR , Mason TO , Dravid VP
Published: July 2020

Transparent conductive oxide materials (TCO) are currently under development for use as electrodes in optical systems such as photovoltaics and flat panel displays. Indium-tin based oxides and cadmium-tin based oxides have been investigated in the past but have received more attention recently due to their high electron mobilities. The mechanisms for conduction in these systems are not fully understood, but the distribution of cations within the lattice is thought to be of importance. We are currently studying the Cd1+xIn2-2xSnxO4 system for use as a TCO material. In particular, we are interested in the effect of the crystallography and cation distributions in this material upon its electro-optical properties.

The investigation of cation distributions in this spinel system presents special challenges to purely diffraction based methods. X-ray diffraction cannot be used to assess the cation distribution for this system due to the similar x-ray atomic scattering factors for the cations involved.
Transmission Electron Microscopy Studies of Natural Nanomaterials from the Solar System
Authors: Dai Z R , Bradley J P , Snow T P , Wang Z L
Published: July 2020

It is widely appreciated that the study of (man-made) nanomaterials is a new frontier in materials science, but it is not well appreciated that (natural) nanomaterials represent a new frontier in meteoritics and planetary science [1]. During the next decade the nanogram to microgram quantities of extraterrestrial materials will be returned to Earth from a variety of solar system bodies including comets [2]. Studies of cometary interplanetary dust particles (IDPs) collected in the stratosphere, as well as mass spectrometry data from grains analyzed in-situ at comet Halley, suggest that the returned comet samples will be heterogeneous on a scale of nanometers [3, 4]. (A single 5-10μm diameter IDP may contain >106 individual grains and many different minerals (metal, carbonaceous phases, silicates, sulfides, etc.)). More recent observations of dust around stars, in interplanetary space, and at comet Hale-Bopp indicate that the predominant astronomical grain size is in the nanometer to submicrometer size range [5,6].
Microscopy of Airborne Particulates from Opencast Coal Pits.
Authors: Jones T P , Reynolds L J , BéruBé K A , Richards R J
Published: July 2020

In the UK, ambient levels of PM10 are approximately 20-30 micrograms/m3 but may increase 10-fold during pollution episodes. There have been concerns expressed about the possible detrimental health effects of breathing particulates generated by opencast coal mining in the United Kingdom (e.g. Glyneath in Wales, 1997). However these fears have not been confirmed due to lack of adequate monitoring, characterisation, and source apportionment of PM10. We have collected airborne particulates from several sites within ‘Park Slip West’ coal opencast pit, which is situated in the south of Wales, UK. This collection constitutes the first half of a project to collect and characterise particles, followed by an assessment of their bioreactivity. The characterisation includes Field Emission SEM, SEM-EDAX, TEM-EPXMA, ICPMS and Image Analysis.

Particles were collected using high-volume air samplers operating at pre-calibrated flow rates of 30L/minute, attached to PM10 selective-inlet heads.
High-Resolution TEM Investigation of Halloysite
Authors: Ma Chi , Eggleton Richard A
Published: July 2020

Halloysite has long been regarded as being highly-disordered or even turbostratic structurally. TEM study of halloysite in the past showed little detail in the basal fringes due to rapid beam damage. Most TEM images of halloysite with various morphologies reported in recent literature are at low-magnification. In this study, tubular halloysites from six localities in Australia and New Zealand were intensely examined with HRTEM and electron diffraction using a JEOL 200CX. The results are presented in this paper.

Tubular halloysite (Fig. la) HRTEM images recorded show a 7-Å fringe spacing (Fig. lb), which suggests that halloysite has lost its all interlayer water and has collapsed under the high-vacuum conditions in the TEM. The 7-A lattice fringes revealed on the walls of halloysite tubes are similar to those of kaolinite stacks, and exhibit relatively straight layers with fewer defects compared with smectite fringes.
Microstructure and Thermal Conductivity of AlN(Y2O3) Ceramics
Authors: Bailey GW , McKernan S , Price RL , Walck SD , Charest P-M , Gauvin R , Yu Y D , Hundere A M , Høier R , Einarsrud M -A , Dunin-Borkowski R E
Published: July 2020

Aluminum nitride (AIN) with high thermal conductivity has been considered as a potential substrate material for microelectronics. However, the thermal conductivity of polycrystalline AIN ceramics, prepared by liquid-phase sintering, is significantly lower than that of AIN single crystal. It has been shown that the thermal conductivity of AIN is inversely proportional to the oxygen content dissolved in the AIN lattice. Furthermore, the microstructure of AIN can also influence the thermal conductivity considerably. In the present study, we investigated the effect of grain boundaries and secondary phase distributions on thermal conductivity of two selected high density samples which contained similar oxygen content but showed different thermal conductivities.

Experimental details and selected properties of Samples A and B are shown in Table 1. Sample A with 0.8 wt% Y2O3 additive was embedded in an AIN powder bed in a BN crucible covered by a BN lid (not gas tight) during sintering, while Sample B with 3.9 wt% Y2O3 was embedded in an AIN powder bed in an open graphite crucible.
Coal Slag Reaction with High Chrome Refractories
Authors: Collins W K , Rawers J C , Peck L M , Hunt A H
Published: July 2020

ABSTRACT: Coal gasifiers are required to operate at very high temperatures, >1600°C, for long periods of time, > 13 months (10,000 hours) Fig.1. Under these conditions the refractory lining of choice is high chrome refractory. During operation coal contaminants form a liquid slag that run down the chamber walls which can react with the refractory walls. Albany Research Center has designed a series of experiments to understand the slag-refractory interactions, with the intent of eventually being able to reduce or minimize the problem and thereby extending the gasifier operation time before relining. To understand the slag-refractory interaction, elemental components of the slag have been allowed to react with the refractory under simulated gasifying conditions. The interactions have been characterized using X-ray diffraction, electron microscopy, elemental x-ray mapping, and quantitative microanalysis.
Interfacial Microstructure and Crystallographic Orientations of Thick YBa2Cu3O7 Films Deposited on CeO2/LaAlO3 Substrate
Authors: Wu Lijun , Zhu Yimei , Suenaga M , Solovyov VF , Wiesmann HJ , Sabatini RL
Published: July 2020

The development of YBa2Cu3O7 (YBCO) thick films on a flexible, textured, metallic substrate has recently attracted considerable scientific and technical interest. It is well known that the interfacial microstructure plays an important role on the formation and alignment of the YBCO films. Thus, understanding the evolution of the phases near the substrate interface will help us to improve the quality of the films. In this study, BaF2, Cu, and Y were deposited on the (001) CeO2/LaAlO3 substrates without external heating in vacuum. Subsequently, a series of these films were annealed at 735°C for preselected time periods and then quenched. Similar to YBCO films on SrTiO3 substrates, (Ba, Y, Cu)(F,O)2 (precursor) and Cu2O phases were formed after annealing for 10 minutes. After 12 hours annealing, the formation of YBCO film was completed.
Epitaxial Platinum Films on (0001) Sapphire: a Microstructural Study
Authors: Ramanathan S , Clemens BM , Mclntyre PC , Dahmen U
Published: July 2020

Epitaxial platinum films are used as seed layers in a number of magnetic and ferroelectric devices. It is hence very important to understand the microstructure of the seed layer to control the subsequent multilayer growth. Previous studies of epitaxial Pt films have focused on AFM, XRD and RHEED measurements. However, there has been no detailed analysis of the microstructure as of yet. In this paper, we present results of a systematic study of the microstructure of epitaxial Pt films using conventional and high resolution transmission electron microscopy.

Platinum films were grown by sputtering in an UHV chamber at 500°C on (0001) sapphire. Figure 1 shows a plan view bright field image of a Pt film with the inset showing the <111> diffraction pattern. The spot pattern confirms the epitaxial nature of the film.
Microstructure of TiC/Amorphous Hydrocarbon Nanocomposite Coatings
Authors: Cao D M , Jiang J C , Feng B , Meng W J
Published: July 2020

Application of an appropriate ceramic surface coating to mechanical components such as bearings and gears can provide longer life and increased performance reliability. Metal-containing hydrocarbon (Me-C:H) coatings possess high hardness, together with low friction and low wear rate. They have also been suggested to adhere better to metallic substrates. This combination of attractive mechanical/tribological properties makes Me-C:H coatings potentially useful for surface modification of a wide range of mechanical components.

Using the technique of inductively coupled plasma (ICP) assisted vapor deposition[1], we have synthesized Ti-containing hydrocarbon (Ti-C:H) coatings with a wide range of Ti compositions[2]. Coating mechanical properties such as modulus and hardness have been measured by the technique of nanoindentation and correlated to Ti and hydrogen compositions[2,3].

We have performed detailed microstructural examination of Ti-C:H coatings by transmission electron microscopy (TEM), Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, and X-ray Absorption Near Edge Structure (XANES) spectroscopy.
Transmission Electron Microscopy Study of Tin Oxide Thin Films Deposited on the Sapphire Substrate
Authors: Dominguez J E , Fu L , Pan X Q
Published: July 2020

Thin films of tin oxide (SnO2) with the rutile structure are the subject of many investigations due to their potential applications, such as gas sensing devices, lithium batteries cathodes and solar cells. There is a growing interest in the development of gas sensors using SnO2 thin films due to their high surface to volume ratio. Previous studies have shown that the gas sensing properties of SnO2 are very dependent on the microstructure and that doping elements can greatly influence their electrical properties. In this paper we present transmission electron microscopy (TEM) studies of the microstructure and crystal defects of SnO2 thin films.

Tin oxide films 5 nm in thickness were deposited on the surface of sapphire (A12O3) by pulsed laser ablation of ceramic SnO2 targets. The film microstructure was studied using X ray diffraction, atomic force microscopy and transmission electron microscopy. Defects were studied using high resolution transmission electron microscopy (HRTEM).
Roughness Measurements on Thin Magnetic Layers using Energy-Filtering TEM
Authors: Grogger Werner , Cheng Ning , Krishnan Kannan
Published: July 2020

In the deposition process of thin layers the surface roughness of the substrate as well as the roughness of layers and/or interfaces may have a strong influence on their physical properties. For example, the interfacial roughness has turned out to have a big influence on the magnetic behavior in exchange-coupled antiferromagnetic and ferromagnetic thin films. Since roughness can be of different kinds, one has to differentiate between physical, chemical and in this case, magnetic roughness. The former two can be differentiated in terms of their spatial frequency or ‘wavelength': for chemical roughness the local chemistry (ie. the positions of individual atoms) is crucial, meaning, that it takes place at very short wavelengths. On the other hand, physical roughness is determined by wavelengths much longer than atomic distances.

The surface roughness of a material (physical roughness) is often measured using an atomic force microscope. If interfacial roughness is of interest, cross-sectional samples have to prepared in order to have access to the desired information.
Ni-Coated Optical Fibers by Electroless Plating
Authors: Lin Yuli , Hwang Li-Jang
Published: July 2020

Optical fibers have been extensively employed in a variety of fields. However, the need of high strength, excellent resistance to moisture permeation and tolerance to heat becomes apparent when such optical fibers are used in nuclear power plants and chemical plants in particular. Plastic coatings as conventional made of optical fibers cables would be replaced by the optical fiber coated with a layer of metal.

Several techniques have been applied to make a metal coating for the optical fibers. Dipping method, to pass optical fibers through a bath containing metal melt, was found the simplest. This dipping method, however, suffers from a disadvantage of a generation of a microbent due to the differences of the linear expansion between metal and the silica substrate [1]. Moreover, the control of the thickness was found difficult using the dipping method. Chemical vapor deposition was also used to form the metal coating on optical fibers.
Microscopy Study of Polycrystalline Chalcopyrite Thin Films
Authors: Witcomb MJ , Alberts V
Published: July 2020

The I-III-VI (I= Cu, III= In and VI= Se) ternary chalcopyrite semiconductors are promising materials for the fabrication of thin film solar cells. The device properties of these polycrystalline CuInSe2-based solar cells are critically influenced by their structural features (i.e. grain sizes, uniformity and defect chemistry) and therefore require careful optimization. The structural features of the films were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The results from this fundamental study were used to compare and evaluate the respective thin film growth methods in terms of producing device quality material for solar cell application.

In order to investigate the influence of the structural properties on device performance, samples were prepared by various growth techniques. The composition (Cu/In atomic ratio) of the films as well as the growth conditions were varied in order to obtain optimum material properties. All films were deposited on Mo-coated glass substrates and the typical layer thickness were around 2μm.
In Situ TEM Study of Straining of Free Standing Nickel Thin Films
Authors: Chiou W-A , Mitra R
Published: July 2020

In situ dynamic experiments in the TEM provide a powerful and unique method of investigating materials, when they are subjected to different environments or treatments. Study of plastic deformation mechanisms of free standing thin metallic films have evoked strong research interest in recent years. In the past, free standing thin metallic films have been tested in tension, where the tensile properties were measured and compared with those of bulk samples. Certain other studies dealt with metallic films attached to the substrate, where the deformation was introduced by thermal cycling or mechanical straining. The deformaion of bulk nanocrystalline samples has also been extensively studied recently. However, few publications have documented in situ straining of free standing metallic films with ultrafine grain size. In this study, an in situ straining stage was employed in the TEM to deform a free standing thin nickel film with grain sizes in submicron and nanocrystalline range, and the goal was to observe the microstructural response to deformation.
Advances in Microwave Assisted Specimen Processing. Benefits and Limitations Analyzed in Plant Nuclei and Drosophila Embryos in Vivo
Authors: Gartner David M , Sanders Mark A
Published: July 2020

Abstract

Recently, specimen processing using microwave irradiation was described as a potential tool to enhance a variety of procedures used in microscopy including fixations, embedding, antigen retrieval (AGR) and immunolabeling (1,2,3). A comparison of conventional staining and staining after microwave irradiation was performed for several fluorescent vital nuclear stains, Performing the labeling reaction under controlled microwave irradiation results in significant improvements in the labeling of nuclei, such as shortening the times of incubation and allowing the detection of otherwise inaccessible sites. In addition to investigate the basis of the enhancement, we have labeled intact samples such as living onion root meristems and Drosophila embryos. In both systems, vital fluorescent nuclear stains were applied to the specimen on a glass slide and was microwave irradiated using a variable wattage microwave (model 3451 Ted Pella, Inc.). This resulted in clear fluorescent labeling of the nuclei. This result has not been previously reported in the absence of microwave treatment, other than by microinjection.
Magnesium Acetate: A Divalent Light-Atom Cationic Negative Stain
Authors: Massover William H
Published: July 2020

Negative staining is very useful, but typically produces a resolution level of 20-25A and thus reveals only the quaternary level of protein structure. The recent finding that heavy metals are not required to obtain sufficient contrast for direct TEM imaging has led to examinations of various light atom compounds in a search for new unconventional staining agents having improved properties that can lead to higher resolution. This report examines whether the acetate salt of a divalent cation, magnesium, can function successfully for experimental negative staining.

Magnesium acetate (Mg(C2H3O2)2˙4H2O) (F.W. = 214.5) was used as an aqueous solution at 200mM. Bovine liver catalase crystals were examined as test specimens under standardized conditions. Suspended crystals were deposited onto a hydrophilic thin carbon supporting film and then were negatively stained by the on-grid procedure described previously. Imaging at l00kV used a JEOL 100-CX transmission electron microscope with Kodak S0-163 film.
Ultrastructural and Histochemical Characterization of Secretory Granules in Human Lung Adenocarcinoma Cells
Authors: Aktas R G , Demiralay E , Altaner S , Candan L , Kutlu A K
Published: July 2020

Histochemical methods offer an excellent research tool for the characterization of glycoproteins in the secretory cells, thus contributing to the elucidation of the pathophysiology of different diseases. The different staining characteristics of mucins can be useful in diagnostic histopathology. It has been proposed that the reduction in sulphated glycoproteins and an increase in sialomucins in intestinal mucosa was an indicator of premalignant changes in carcinoma of the bowel. It has subsequently argued that this change may be consequence rather than a precursor of neoplasia. It may still be of some value as a marker of a premalignant change although it is somewhat variable. Previous studies have demonstrated the characterization of glycoproteins in different type of epitheloid cells in normal and pathologic conditions by using histochemical and electron microscopic techniques. However; little information has been available concerning the exact features of secretory granules in both normal and tumoral cells in lung.
Identification of Scavenger Receptor Sr-Bi in The Endothelial Cells and the Smooth Muscle Cells of Rat Aorta in Vitro and in Vivo
Authors: Liu Y P , Yeh Y C , Yang V C
Published: July 2020

The class B, type I scavenger receptor (SR-BI) was the first molecularly well defined cell surface receptor which binds HDL and mediates the selective uptake of HDL cholesteryl ester. It is expressed primarily in liver and steroidogenic tissues. However, the recent studies also suggested a potentially important role of SR-BI in the initial steps of cholesterol efflux in the peripheral tissues. In this study, we have used immunofluorescence and immunoelectron microscopy to study the expression and subcellular localization of SR-BI in the endothelial cells and the smooth muscle cells of rat aorta in vitro and in vivo.
FIB/TEM Sample Preparation using a Wafer Dicing Saw
Authors: Tsung Lancy , Anciso Adolfo , Davidson Bruce , Turner Robert , Alqaq Tareq , Skloss Alois
Published: July 2020

As device features shrink below sub-0.2 micron and the time from development to market reduces, the demand for using focused ion beam (FIB) to prepare TEM samples has increased tremendously over the last two years in semiconductor industry. There are many ways to prepare a TEM sample prior to the FIB one of them involves with a use of dicing saw. In our lab, about 80% of the samples were prepared using the dicing saw technique. Average time to cut out one sample is less than 20 minutes.

The dicing saw we used is a Disco model DAD321 equipped with a 250X optical and ccd camera viewing monitor system. To minimize chipping, a 200 um-thick diamond resin composite blade is used. A spindle rotation speed at 30,000 rpm and a stage moving speed at 100 mm/s is set for minimizing blade ware and sample chipping. The parameters for each cut are pre-programmed, so there is no setup required.
Revisiting the FIB TEM Lift-Out Specimen Preparation Technique
Authors: Giannuzzi L A , Stevie F A
Published: July 2020

In recent years, the focused ion beam (FIB) instrument has developed into a mainstay tool for the production of specimens for both scanning and transmission electron microscopy ((S)TEM). The inception and subsequent development of the FIB TEM lift-out (LO) technique has enabled electron transparent membranes of generally uniform thickness to be produced for TEM analysis. In general, the primary advantage of the FIB is that site specific sections may be fabricated quickly (e.g., < 1 hour) and reproducibly. Specifically, the FIB LO technique has been used extensively in our laboratories to produce on the order of a thousand Si-based specimens per year and hundreds of other specimens per year that have included metals, ceramics, composites, biological materials, geological materials, polymers, particles, and fibers, prepared in cross-section, plan view, and from fracture surfaces.
Site Specific TEM Specimen Preparation using an FIB/TEM System
Authors: Kamino T , Yaguchi T , Ohnishi T , Umemura K , Tomimatsu S
Published: July 2020

The focused ion beam(FIB) technique, developed for the microelectronics industry has become a major method for site specific transmission electron microscopy(TEM) specimen preparation in a wide range of materials[l]. The FIB lift-out technique has improved the specimen preparation procedures by removing complicated initial fabrication required prior to the FIB milling[2]. However, conventional FIB techniques are still having increased difficulty in meeting failure analysis needs from high technology industries such as microelectronics.

We have developed a site specific TEM specimen preparation method using a combination of an FIB instrument and an intermediate voltage TEM equipped with a scanning attachment [3]. In this method, the specimen is mounted on an FIB-TEM compatible specimen holder, so that localization of the specific site can be carried out in the FIB and TEM using the same holder. The scanning electron imaging mode may be used to observe surface structures of the milled area, and the scanning transmission electron microscopy(STEM) mode may be used to observe structures inside of the milled surface.
Precision TEM Specimen Preparation for Integrated Circuits using Dual-Beam FIB Lift-Out Technique
Authors: Xu Youren , Schwappach Chris , Cervantes Ron
Published: July 2020

Focused ion beam lift-out technique has become increasingly attractive to the TEM community due to its unique advantage of no mechanical grinding/polishing involved in the process [1-3]. The technique essentially consists of two parts: preparation of membrane using focused ion beam (FIB) and transfer of the membrane (lift-out) to a grid. Up to date, this technique has only been demonstrated on single beam FIB systems. From a practical standpoint, overall sample quality (thickness) and lack of end-point precision are two major issues associated with the conventional single beam FIB technique. These issues are primarily related to ion beam damage and endpoint control encountered during the final stages of specimen thinning. As a result, the widespread use of FIB lift-out technique for high precision TEM specimen preparation has been limited. Recent technological advances have made it possible to combine both an electron beam column and an ion beam column into an integrated dual beam-focused ion beam (DB-FIB) system.
Chain Structure Defect Location by Focused Ion Beam Passive Voltage Contrast
Authors: Rossie BB , Shofner TL , Brown SR , Shuttleworth DM , Nguyen D
Published: July 2020

Defects present in microelectronic devices are often present in test structures as well. This makes test structures useful in identifying defect mechanisms. Chain patterns consists of thousands of contacts and plugs in series. The presence of an open contact in a chain can be detected by a loss of electrical continuity. The specific site of an open contact is difficult to locate for further analysis.

The application of the focused ion beam (FIB) for passive voltage contrast (PVC) provides an effective method for contact defect location. Once the defect is located the FIB facilitates efficient site-specific specimen preparation for scanning electron microscopy (SEM), transmission electron microscopy (TEM) or Auger analysis.

The FIB is capable of PVC analysis by distinguishing electrically isolated conductors from grounded conductors. Isolated conductors charge as a result of ion beam interaction. Once charged, the quantity of secondary electrons available for detection is greatly reduced.
The ECM-Integrin-Cytoskeletal Link: A Possible Site for Mechanical Signaling in the Heart
Authors: Terracio L , Carver W , Price RL , Salters R , Simpson DG
Published: July 2020

The cardiac interstitium is a diverse system of extracellular-matrix (ECM) components organized into a stress tolerant three-dimensional network that interconnects the cellular components of the heart. During each contraction of the heart, a complex set of mechanical forces is transmitted through the cardiac interstitium and is applied to the cardiac myocytes and fibroblasts. In comparison to the relaxed heart, each contractile wave results in a rapid reorganization of the extracellular matrix and cell cytoskeleton. A number of studies have shown that by varying the normal pattern of applied mechanical force that occurs during heart contraction, both the phenotype and function of myocytes and fibroblasts in the heart may be altered.

At the molecular level components of the ECM are attached to the cardiac myocytes and fibroblasts via specific transmembrane integrin receptors. Each integrin is comprised of an extracellular domain that attaches to an ECM component, and an intracellular domain that attaches to a cytoplasmic component of the cell.
Intravascular Ultrasound in the Determination of the Mechanical Properties of Diabetic Arteries
Authors: Vince D Geoffrey , Tajaddini Azita , Veress Alex I
Published: July 2020

Cardiovascular disease is the leading cause of morbidity and mortality in diabetic individuals. Diabetes mellitus is associated with a two- to four-fold increase in risk of coronary heart disease. This risk is independent of other classical risk factors including age, smoking, elevated serum cholesterol levels, and hypertension, and the overall risk of cardiovascular disease increases proportionally with the number of risk factors. Many groups are currently investigating the aetiology of diabetic vascular disease, with particular interesting being paid to the processes involved in the formation of highly cross-linked carbohydrate-protein complexes known as melanoids. These complexes appear to be formed by glycation arising from reactions between glucose and the amino groups on proteins, and their formation within the vessel wall resqlts in a decrease in vascular elasticity. This decrease in elasticity has been implicated in the increased incidence of atherosclerosis in diabetic individuals. Previous testing modalities could not test in the radial direction and required assumptions based on incompressibility in order to determine the radial behavior of the artery.
Endothelial Cells Influence the Organization of Fibrin Clots
Authors: Jerome W Gray (Jay) , Handt Stefan D , Hantgan Roy R
Published: July 2020

Heart attack and stroke remain a major cause of death and morbidity in the United States. In most cases, these are caused by the formation of an occlusive thrombus overlying an atherosclerotic lesion. Lysis of these occlusive clots by the infusion of lytic agents is now an approved treatment for heart attack patients. However, lytic therapy is not always successful. The reasons for the failures are not clear. Resistance to thrombolysis is multifaceted and involves the key elements of the clot; fibrin, platelets, and endothelial cells. In previous studies we have shown that, in vitro, secretion of plasminogen activator inhibitor-1 (PAI-1) by platelets and endothelial cells is a factor influencing resistance. However, PAI-1 secretion could not account for all of the lysis delay.
High Throughput Quantitative Analysis of Atherosclerosis tn Mice
Authors: Sanan David A , Ladha Zuleika , Newland Dale L
Published: July 2020

For the past 7 years we have been measuring atherosclerosis in murine models of the human disease, constantly honing our methods for quantitating the atherosclerotic response of mice that have been genetically, dietarily or pharmaceutically manipulated to help understand and control the disease process.

With the advent of genetically modified mouse models, investigators now have more robust atherosclerotic responses to quantitate. The surface area of lesions along the entire length of the aorta is a key parameter used to evaluate these responses. We routinely perform quantitative morphometry of intimal atherosclerotic lesions in pinned-out mouse aortas, also called en face lesion analysis.

The number and scale of mouse atherosclerosis studies has increased beyond the capacity of our core laboratory to provide service. While the “wet” processes involved in preparing vascular tissue for atherosclerosis analysis have already been streamlined, we found considerable scope for improving the computer-dependent “back-end” of the analysis.
The 3D-Architecture of the Blood Vascular System of the Ventral Tail Fin in Tadpoles of Xenopus Laevis Daudin: Intravital Microscope Observations and Scanning Electron Microscopy of Vascular Corrosion Casts
Authors: A. Lametschwandtner , B. Minnich , I. Margreiter , R. Sommer , Stollinger T
Published: July 2020

Abstract

Hemodynamics and 3D- architecture of the vascular network of the ventral tail fin of tadpoles of the South African Clawed Toad, Xenopus laevis Daudin were studied by intravital video microscopy (IVM) (stage 56) and vascular corrosion casts (VCCs)(stage 58). IVM enabled a detailed study of the circulation in segmental arteries, segmental venules and interposed capillaries. SEM of VCCs and 3-D morphometry allowed exact measurements of vessel diameters.

Anuran tadpoles are good models to study blood vessel growth (=angiogenesis) (1-3) as well as blood vessel regression which occurs physiologically when tadpoles loose larval specific organs such as gills and tail during metamorphosis (4,5). The translucent ventral tail fin enables in-vivo observations of the living circulation by intravital light microscopy (1,2) and allows correlations between vessel fine structure and dynamics of blood flow under various conditions (2).

This study focuses on the 3D-architecture of the blood vascular system in the ventral tail fin of tadpoles of Xenopus laevis Daudin in stage 58, i.e. at the begin of metamorphic climax.
Studies on the Orbital Heating Organ of the Swordfish (Xiphias Gladius) using Microvascular Corrosion Casting
Authors: Bailey GW , McKernan S , Price RL , Walck SD , Charest P-M , Gauvin R , Ditrich Hans , DeMetrio Gregorio
Published: July 2020

The swordfish ﹛Xiphias gladius), as well as billfishes (Istiophoridae), shows a conspicuous modification of one of its eye muscles: the dorsal rectus muscle. While the other eye muscles show an apparently normal, oculomotoric structure, the musculus rectus dorsalis is modified for heat production. While the remaining oculomotoric portion of this muscle shows normal muscular cells, the bulk of the organ is composed of cells structurally similar to brown adipose tissue (BAT) and blood vessels. The BAT cells are capable of direct (i.e., non-shivering) metabolic heat production. This heat is then transported and disseminated by the blood vessels in this organ.

Microvascular corrosion casting is an excellent technique for studying the morphology of complicate vascular networks. However, studies using this technique on eye muscle vasculature are not frequently found in the literature. Juvenile swordfish, 1.4-1.8kg bodyweight, were collected in the Ionic sea. Immediately after catching, terminal anaesthesia was carried out with tricaine-methanesulfonate.
Imaging and Volumetric Quantitation of Vascular Corrosion Casts with Laser Scanning Confocal Microscopy.
Authors: Bailey GW , McKernan S , Price RL , Walck SD , Charest P-M , Gauvin R , Czymmek K , Wagner R C , Hossler F E , Kao R
Published: July 2020

Vascular corrosion casts provide faithful replicas of the three-dimensional anatomy of blood vessel system of organs and tissues. In addition, corrosion casts can be used to obtain quantitative information regarding vessel and tissue spaces. However, morphometric measurements of SEM images of corrosion casts is difficult due to severe specimen tilt, parallax and the inability to image 3D casts from all angles. We present evidence that confocal microscopy can be used to collect all of the 3D information of a corrosion cast in a z-series of optical slices. Surface and volumetric parameters of casted and non-casted space are readily retrievable from a stack of optical sections through a corrosion cast.

Various tissues and organs were exsanguinated with heparenized saline following cannulization of regional arteries and casts were made by infusing Mercox resin or Mercox diluted with 20% methyl methacrylate monomer. Tissues were macerated with alternating rinses in 5% KOH and hot water.
Blood Supply of Primary Auditory Cortex in Chinchilla: A Corrosion Cast Study
Authors: Mount RJ , Harrison RV , Harel N , Panesar J , Hamrahi H
Published: July 2020

INTRODUCTION: The chinchilla animal model is widely used to study the function of the auditory system. The location of auditory cortex in the chinchilla has previously been determined both electrophysiologically and by optical imaging of intrinsic signals. The spatial resolution of functional imaging techniques which rely on changes in the BOLD (blood oxygen dependent level) signal to create images of activity (i.e., fMRI and optical imaging) are ultimately dependent on the resolution of microcirulatory control mechanisms. For example, in response to pure tone auditory stimuli, functional resolution (within cortex) of approximately 400 um has been demonstrated using optical imaging. To better understand the limits of functional imaging the present study was undertaken to explore the structure and properties of the arterial supply within auditory cortex.

METHODS: Plastic casts of the cerebral vasculature were prepared by cannulating the ascending aorta, incising the right atrium and then perfusing 50 ml heparinized PBS followed by 20 ml of Batson's #17 resin.
Angiogenesis in Human Gastrointestinal Tumors: An Immunohistochemical and Immuno-Electron Microscopy Study
Authors: Tonino P , Finol HJ , Hidalgo C , Sosa L
Published: July 2020

Angiogenesis, the process of new blood vessels formation, is a crucial step in tumor growth and progression. Its quantitation by microvessel counting is of pronostic value in several types of malignancies, because it indicates a tumor's capacity for inducing angiogenesis. However, scarce data are available on angiogenesis in gastrointestinal tumors. Our previous work has revealed that gastrointestinal adenocarcinomas (GADC) vessels are anatomically heterogeneous structures. Additionally, it has been suggested that tumor-induced neovascularization in human carcinomas does not simply mean proliferation of capillaries, but it is also associated with certain functional changes in the vascular endothelial cells. Factor VTlI/von Willebrand factor (vWF) has been widely used for the demonstration of vascular endothelial cells as a representative marker. The aims of the present study were a) to determine whether the vascular density in GADC can be correlated to tumor aggressivness and provide prognostic information, and b) to clarify the ultrastructural immunolocalization of vWF in microvessels in the stroma of these tumors.
Apoptosis Revealed by Epifluorescence can be Compared with Silica Localization by SEM Backscatter using Paraffin Sections on Carbon Planchets
Authors: Millecchia L , Mercer R , Schwegler-Berry D , Willard P , Friend S
Published: July 2020

In investigating pathological changes that occur during development of fibrosis in lungs exposed to silica, we found a significant increase in apoptotic cells in rats exposed to silica by inhalation for 80 days. Since silica is not definitively detected at the light level, we sought to use SEM backscatter imaging to correlate the presence of silica with apoptosis identified by fluorescent assays. To accomplish this, paraffin sections of lungs from rats that had been exposed to silica were placed on carbon planchets. Serial sections were placed on glass slides, immediately before and after the section on the planchet. Using a fluorescein apoptosis detection system (Promega G3250), a TdT-mediated dUTP nick-end labeling (TUNEL) assay was performed on both planchets and slides. The planchets and slides were cover slipped with gel/mount (Biomedia) and viewed in an Olympus AZ70 fluorescent photomicroscope with a wide band blue filter cube. Apoptotic nuclei could be seen in similar regions in both the slide and the planchet preparations.
Ultrafine Particles Penetrate Human Airway Epithelium Resulting in Increased Expression of Genes Causally Related to Cell Proliferation and Apoptosis
Authors: BeruBe K , Timblin C , Shukla A , Churg A , Mossman B
Published: July 2020

Epidemiological studies have associated exposure to airborne particulate matter (PM) with an aerodynamic diameter less than 10 microns, especially the finer fraction PM2.5, with increases in morbidity and mortality in persons with preexisting cardiopulmonary disease. However, whether exposures to PM10 cause lung disease in uncompromised individuals is a topic of debate, especially since mechanistic and toxicological studies have failed to define cause and effect relationships between exposures to PM10 and phenotypic changes associated with the development of pulmonary diseases. PM10 is a complex mixture of soot and natural minerals, metal oxide particles, sea salt grains and aeroallergens (Fig. 1). Our interest lies with the carbonaceous components (Fig. 2), since insoluble particles may be more efficiently retained in the peripheral lung and be potentially more bioreactive due to their accumulation over time. We are interested in the ultrafine (UF) fraction (<1.0um diameter) since the number of particles in this size range are known to increase during pollution episodes and they have a greater reactive surface area per unit weight.
Ultrastructural Pathology of Neurofibrillary Tangles in Transgenic Mice Carrying Mutant (P301l) Human Tau Gene
Authors: Lin W-L , Lewis J , Corral AR , Dickson DW , Hutton M
Published: July 2020

Tau is a microtubule-associated protein that promotes polymerization and stabilization of microtubules. It is the major component of fibrillary neuronal and glial inclusions in Alzheimer's disease (AD) and the tauopathies. An autosomal dominant familial tauopathy, frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), has been shown to be caused by pathogenic tau mutations. Neuropathologic features of FTDP-17 are filamentous tau aggregates in neurons and glia. Previous transgenic mice carrying the normal human tau gene developed motor neuron disease and had dystrophic axons, but no neurofibrillary tangles (NFT). In this report we describe ultrastructural features of NFT in transgenic mice carrying a mutant human tau gene. The mice were generated with a tau cDNA containing exon 1, 4, 5, 7, 9, 10, 11-13, intron 13 and exon 14, driven by the mouse prion promoter (MoPrP) and containing the most common FTDP-17 mutation, P301L. The transgenic construct was generated by ligating the P301L tau cDNA with the mouse prion promoter.
Evaluation of the Ultrastructural Anaplastic Changes Observed in Benign Thyroid Tumours
Authors: Huseyinova G , Hatipoglu AR , Karakaya K , Irfanoglu ME
Published: July 2020

Proliferation, polymorphism and papillary hyperplasia of the follicular cells and endothelial cells can be often observed on the benign structural background of the thyroid follicular adenoma and this makes it difficult to find out the malignancy with Ught microscopy (1,2,3). The ultrastructural anaplastic changes of the cells and organelles called our attention. Recently some of the authors think that any papillary change in thyroid is the evidence of malignancy.

Twenty cases with follicular adenoma, ten cases with papillary carcinoma of the thyroid diagnosed with light microscopy were re-evaluated with electron microscopy in classical methods. In papillary carcinoma cases anaplastic changes of the tumour cells was showed ultrastructurally (Fig 1). Two of them, with no capsular or vascular invasion observed with Ught microscopy, there were proliferation of the microvilli in the apical parts of the thyrocites, and papiUary projections observed obviously. There were cystic dilations in cytoplasm and a lot of indentations of the nuclei.
The Ultrastructure of Cadaverous Skin after Cryopreservation with Polyethylene Oxide-400
Authors: Migunova R , Sandomirski B , Kaprelyants A
Published: July 2020

The cryopreservation is the method of selection of long-term skin preservation used for the closure of large wound defects and the only possibility of long preservation of graft skin material in the viable state. For the lowtemperature preservation of human skin was successfully used cryoprotectant Polyethylene oxide -400, which was confirmed by the clinical evaluation during autotransplantation /1/. At the same time many aspects of the influence of low temperatures on the ultrastructural skin components were unclear /2/. The investigation of subcellular elements during step of low-temperature preservation specifies mechanisms of influence on the tissue preservation factors and determine the condition of skin cellular elements /3,4,5/. The aim of this work is to study ultrastructural characteristics of human cadaverous skin during the stages of low-temperature preservation by PEO-400.

In this investigation epidermal skin grafts with the thickness of 0.4-0.6 mm were studied in 6 hours after the accidental death divided in 3 series:
The Effects of Cyclosporine on Protein Expression of P53 and Transforming Growth Factor-Beta in Human Renal Tubular Cells
Authors: Song H , Wei C
Published: July 2020

Cyclosporine-A (CsA) is the widely used immunosuppressant drug in renal transplantation. However, the effects of cyclosporine-A are limited by a significant nephrotoxicity. The mechanisms of CsA-induced allograft nephropathy are remaining controversial. Recent study indicated that cellular apoptosis may contribute to the cyclosporine A-mediated cytotoxic action. To date, regarding the effects of cyclosporine A on renal cell apoptosis-related gene expression remain poorly defined. p53 is an important gene in control of renal cell growth and death. Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that has anti-proliferative as well as fibrogenic properties.

We hypothesized that cyclosporine-A may increase p53 and TGF-β expression in renal tubular cells. These actions of cyclosporine-A may contribute to the cellular apoptosis, fibrosis and CsA-induced nephrotoxicity. Therefore, current study was designed to determine the effects of cyclosporine-A on the p53 and TGF-βl protein expression by immunohistochemical staining (IHCS) in cultured human tubular cells.