bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of FIB Damage in Silicon
Authors: Urbanik CA , Prenitzer BI , Gianhuzzi LA , Brown SR , Shofner TL , Rossie B , Irwin RB , Stevie FA 
Published: July 2020

Abstract
Focused ion beam (FIB) instruments are useful for high spatial resolution milling, deposition, and imaging capabilities. As a result, FIB specimen preparation techniques have been widely accepted within the semiconductor community as a means to rapidly prepare high quality, site-specific specimens for transmission electron microscopy (TEM) [1]. In spite of the excellent results that have been observed for both high resolution (HREM) and standard TEM specimen preparation applications, a degree of structural modification is inherent to FIB milled surfaces [2,3]. The magnitude of the damage region that results from Ga+ ion bombardment is dependent on the operating parameters of the FIB (e.g., beam current, beam voltage, milling time, and the use of reactive gas assisted etching).
Lattice defects occur as a consequence of FIB milling because the incident ions transfer energy to the atoms of the target material. Momentum transferred from the incident ions to the target atoms can result in the creation of point defects (e.g., vacancies, self interstitials, and interstitial and substitutional ion implantation), the generation of phonons, and plasmon excitation in the case of metal targets.
Effects of Protective Capping on Ultra-Thin SIMOX Structures
Authors: Wilson T , Jiao J , Seraphin S , Johnson B , Anc M , Cordts B 
Published: July 2020

Abstract
Devices for character recognition as well as cellular phones require computational elements that work at higher speeds with lower current requirements. Separation by IMplanted Oxygen (SIMOX) is one type of Silicon On Insulator (SOI) technology that shows great promise in meeting the future demands for faster and more efficient applications. The ultra-thin SIMOX substrates produced by low energy/low dose implant methods make possible the construction of large scale integrated circuits with fully depleted CMOS devices. One of the great challenges in the production of SIMOX technology is achieving high quality Si and Si02 layers. High energy implantation of 0+ ions causes damage to the Si crystal and therefore requires a high temperature annealing step to repair it. Annealing of SIMOX takes place in a mixed atmosphere of argon and oxygen. Having oxygen in the ambient creates a superficial Si02 layer. This reduces the thickness of the SOI layer but also protects the surface from pitting.
The Apex Structure of Co-Produced Helical Boron Nitride and Carbon Cones
Authors: Bourgeois L , Bando Y , Kurashima K , Sato T 
Published: July 2020

Abstract
Conical whiskers of layered compounds such as graphite and hexagonal boron nitride (h-BN)2 are interesting materials because their conical morphology results from the introduction of a local topological defect at the cone apex. In the honeycomb array characteristic of graphite and h-BN basal planes, this topological defect is thought to be a non-hexagonal ring (e.g. a pentagon or a square). These defects are known to form the basis of curved nanostructures like fullerenes and buckytubes. Therefore a comparison of their occurrence in two systems known to harbour nanostructures is worthy of study.
The defect structure at the apex of co-produced carbon and boron nitride whiskers was investigated by analytical transmission electron microscopy (TEM). The instrument used was a field-emission JEM3000F high-resolution electron microscope, equipped with a parallel electron energy loss spectrometer (EELS).
Electron Probe Microanalysis (EPMA) Characterization of Scales Formed on Laves Phase Reinforced Cr Alloys at 1100°C in Air
Authors: Walker LR , Brady MP 
Published: July 2020

Abstract
Laves phase (Cr2X) strengthened Cr solid solution [Cr(X)]-based alloys are under development for a variety of high-temperature structural applications. Among the most promising alloys are castings based on the Cr(Ta)-Cr2Ta eutectic, which exhibit room-temperature fracture toughness in the 10-12 MPa√m range and creep rupture lives in excess of 1000 h at 1000° (138 MPa) in air. These alloys exhibit superior high-temperature oxidation resistance to previously developed Cr(Nb)-Cr2 Nb based alloys despite the general similarities of Ta and Nb. In order to optimize high-temperature oxidation resistance an understanding of why the Cr(Ta)-Cr2Ta alloys are more oxidation resistant is needed. Detailed EPMA characterization of the oxidized scaleswas initiated as a first steptowards gaining this understanding.
Fig. 1 shows a backscattered electron image of cast and heat treated and heat treated Cr-10Nb at.% after a 6 cycle, 120 h exposure at 1100°C in humid air. Most of the coupon was converted to a complex mixture of Cr-, Nb-, and Cr+ Nb- oxides.
Identification of Alpha Prime in an Aged Fe-12cr Steel Using Extraction Replicas and Energy Filtered TEM.
Authors: Larsen M , Angeliu T , Mukira C 
Published: July 2020

Abstract
Long term aging of martensitic Fe-12Cr steels at elevated temperatures can result in a significant decrease in toughness. The mechanism responsible for this has been generally attributed to either impurity segregation and/or precipitation of second phases. The aging embrittlement of higher Cr-containing ferritic steels has long been attributed to the precipitation of bcc Cr-rich alpha prime phase[l]. Alpha prime has also been shown to embrittle certain Ni base alloys [2]. The current work has shown that alpha prime forms in Fe-12Cr steels which have been aged at 450°C for up to 32khrs. Coincident with the precipitation of alpha prime is a marked decrease in toughness.
Historically, extraction replicas and to a limited extent thin-foil TEM microscopy have been used to identify alpha prime. However, both are not without problems in these magnetic, corrosion-resistant steels, due to the fact that the alpha prime is small (&lt;20nm) and coherent with the matrix. Volume fraction studies have been essentially impossible.
Near Real-Time X-Ray Cone-Beam Microtomography
Authors: Ang Shih , Ge Wang , Ping-Chin Cheng 
Published: July 2020

Abstract
Due to the penetration ability and absorption contrast mechanism, cone-beam X-ray microtomography is a powerful tool in studying 3D microstructures in opaque specimens. In contrast to the conventional parallel and fan-beam geometry, the cone-beam tomography set up is highly desirable for faster data acquisition, build-in magnification, better radiation utilization and easier hardware implementation. However, the major draw back of the cone-beam reconstruction is its computational complexity. In an effort to maximize the reconstruction speed, we have developed a generalized Feldkamp cone-beam reconstruction algorithm to optimize the reconstruction process. We report here the use of curved voxels in a cylindrical coordinate system and mapping tables to further improve the reconstruction efficiency.
The generalized Feldkamp cone-beam image reconstruction algorithm is reformulated utilizing mapping table in the discrete domain as: , where .
Pc-Based Imaging System for Color Cell Identification and Scoring
Authors: Suri Jasjit S , Satyender Kumar 
Published: July 2020

Abstract
Pathologists, microbiologists and cytologists are very interested to automatically identify and quantify the sperms, cells or nucleus in the cellular level images. Complexities like voluminous data sets, variability in data sets, millions of colors, and different kinds of artifacts make the detection and quantification process very difficult. This paper is an attempt to design a sophisticated cellular diagnostic system based on color image processing, mathematical morphology and connected components based on run length encoding. This system runs on Windows ‘98/NT PC platform, in Visual C++, 6.0 environment using three different architectures: Single document interface, multiple document interface and dialog based applications. The system takes around 1.5 seconds per image of 512 x 484 square pixels using high speed threading architecture written on the on 400 MHz Pentiumll processor. The system has an accuracy of 95%. The software has been validated tested on NASA and machine vision real world images.
Tapping Mode Near-Field Scanning Optical Microscopy of Molecular Crystals and Thin Films
Authors: Daniel Frisbie C , Kosterin Andrey , Stadniychuk Helena 
Published: July 2020

Abstract
The diffraction of visible light limits the spatial resolution in conventional optical microscopy to about 200-300 nm. In near-field scanning optical microscopy (NSOM), resolution is improved by bringing the light source, such as the end of an optical fiber, very close to the sample surface. Laser light coupled into the opposite end of the fiber propagates down the fiber core and is emitted from the aperture of the tip. When the sample is in the near-field(roughly within one tip diameter of the end of the tip), the spatial resolution is essentially equal to the diameter of the aperture at the end of the tip and is not determined by diffraction effects. Two-dimensional imaging is accomplished by raster-scanning the sample underneath the fiber tip and collecting transmitted or reflected light at a photodetector.
Structural Studies of Dynamin Tubular Crystals by Cryo-Electron Microscopy
Authors: Zhang Peijun , Hinshaw Jenny E 
Published: July 2020

Abstract
Dynamin is a 100 kD GTPase that plays an essential role in clathrin-coated vesicle formation during receptor mediated endocytosis, and in caveolae internalization and may play a role in intracellular membrane trafficking (1). It shares an extensive sequence homology (70% identity) to shibiregene product in Drosophila(2,3). The shibiretsmutants exhibit a rapid and reversible paralysis at non-permissive temperature due to a depletion of synaptic vesicles in their nerve termini which is believed to be caused by a block in endocytosis since there is an accumulation of “collared” clathrin-coated pits at the plasma membrane (4). Synaptosomes treated with GTPγs produces elongated necks surrounded by dynamin (6). Purified recombinant dynamin itself can assemble to form spirals and bind to lipid vesicles to form tubes, which resemble the “collar” at the necks of coated pits (5). These dynamin tubes vesiculate upon GTP treatment (7), suggesting a unique role of dynamin acting as a mechanoenzyme which causes clathrin-coated vesicles to be pinched off plasma membrane.
Ultrastructural Morphology of Cationic Liposome/Dna Complexes for Gene Therapy: Correlation to Transfection Activity
Authors: Sternberg Brigitte , Hong Keelung , Zheng Weiwen , Papahadjopoulos Demetrios 
Published: July 2020

Abstract
Complexes formed during interaction of cationic liposomes with poly-nucleotides such as DNA (CLDC) display a variety of polymorphic and metastable structures. These include multilamellar structures of alternating lipid bilayers and DNA monolayers; fibrillar structures, among them spaghetti-liketubules (Figure 1), and map-pin-structures(Figure 2), and, finally, non-bilayer lipid arrangements, such as hexagonal (HII) (Figure 3) and cubic phases.
In order to find out the “active” structure(s) in terms of transfection, we investigated the transfection activity both in vivoand in vitroof CLDC composed of the lipid DDAB (dimethyl-dioctadecylammonium bromide) and Choi (cholesterol) or DOPE (l,2-dioleoyl-sn-glycerol-3- phosphoethanolamine) as helper lipids. In parallel we studied their morphology by freeze-fracture electron microscopy.The in vivostudies were carried out in mice following i.v. injection and therefore the morphology of the CLDC was investigated in mouse serum.
Androgen-Responsive Lncap and Androgen-Independent Du145 Prostate Cancer Cells Display Different Taxol Sensitivities
Authors: Ripple Maureen , Taylo Meghan , Huese Chris , Schatte Heide 
Published: July 2020

Abstract
Taxol has been used as anti-cancer compound against prostate, ovarian, and metastatic breast cancer. While the most obvious effect of taxol is bundeling of microtubules and mitotic arrest, recent studies have demonstrated that taxol is able to induce intranucleosomal DNA fragmentation and typical morphological features of apoptosis in a number of solid tumor cells. These results indicate that taxol may exert its anti-tumor effects via secondary mechanisms which may or may not be related to its primary effects on microtubules. It has been shown that taxol-induced microtubular changes and G2/M arrest are associated with the release of the electron transfer protein cytochrome C from mitochondria into the cytosol. Cytochrome C then binds to APAF-1 (a human homolog of the ced-4 gene of C. elegans), which binds, cleaves, and activates caspase- 9, ultimately resulting in the cleavage and activity of caspase-3. We investigated the effects of taxol (100nM) on microtubules, on DNA, and on the pre-apoptotic mitochondrial events using LNCaP and DU145 prostate cancer cells.
Enhancement of Differential Interference Contrast Images of Live Cells Obtained With Digital Cameras
Authors: Parthasarathy MV 
Published: July 2020

Abstract
The usefulness of Differential Contrast Interference (DIC) light microscopy for observing fine details within transparent specimens is well known. However, when viewed by the eye or by recording with photographic emulsion, fine structural detail at the limit of resolution is often not visible because of lack of contrast. To overcome this problem, electronic contrast enhancement capabilities of video cameras have been used to enhance structural details that would otherwise be invisible. The technique, commonly referred to as VE-DIC (Video Enhanced DIC), uses first analog contrast enhancement of the image with a video camera followed by a real-time digital image processor to further enhance the image with. We are exploring the feasibility of achieving fine structural detail of live cells by directly acquiring digital images of them with a high resolution CCD camera.
High resolution cooled slow-scan 12-bit CCD cameras are well suited for DIC microscopy because of their greater dynamic range than video CCD cameras that are normally 8-bits or lower.
Application of Cryo-High Resolution (Hr) Sem Technique for Imaging Platelet Morphology
Authors: Wendt MC , Robinson KA , Chronos NAF , Caran KL , Apkarian RP 
Published: July 2020

Abstract
Platelets play a major role in hemostasis due to their ability to adhere and aggregate at sites of vessel wall injury. Damage to the inner surface of arteries includes ruptures or tears at the site of atherosclerotic plaques or injury resulting from interventional procedures. Uncontrolled platelet recruitment and aggregation at these sites can lead to complete occlusion of the vessel. Thus the understanding of platelet function and structure has become an important goal in preventing vascular disease. We employed cryo-HRSEM techniques to gain more insight into the surface morphology of both quiescent and thrombin stimulated platelets.
Platelet rich plasma (PRP) was obtained by mixing whole blood (21 ml) drawn from juvenile pigs with 3 ml of acid citrate dextrose and centrifugation at 300g for 10 min. To obtain washed platelets the PRP was washed three times with a citrate wash buffer consisting of 36mM citric acid, 5mM glucose, 5mM KCl, 2 mM CaCl2, 1 mM MgCl2, 90 mM NaCl, pH 6.5.
Laboratory Safety For the Electron and Correlative Microscopist
Authors: Miller S E , Howel D N 
Published: July 2020

Abstract
Laboratory safety in a diagnostic electron microscopy (EM) laboratory that deals with potentially infectious specimens is a complex issue. The risk of infection of laboratory personnel is an obvious concern, particularly in laboratories, such as diagnostic virology laboratories, which handle infected tissues and body fluids on a routine basis. A second hazard is introduced by the multitude of toxic, corrosive, and irritating chemical reagents required for the preparation of samples for EM. Physical hazards inherent in the complex machinery necessary for EM and other forms of microscopy must also not be overlooked. Attention to each of these concerns must be orchestrated over the course of a multistep process that often lasts several days. Success in this endeavor is facilitated by a comprehensive quality control program encompassing personnel, specimens, chemicals, and equipment.
The foundation for safe handling of samples in the clinical laboratory is the principle of universal precautions, under which all blood, other body fluids, and tissues are considered potentially infectious and handled using appropriate protective measures.
Cytosolic And Membrane Proteins In Plant Cytokinesis
Authors: Bednarek S Y , Dickey C 
Published: July 2020

Abstract
The mechanism of cytokinesis in higher plants is distinct from that of animal and yeast cells. Dividing plant cells are separated by the de novo construction of the cell-plate across the inside of the cell. Assembly of this new organelle is directed by a specialized cytoskeletal structure called the phragmoplast, a unique macromolecular scaffold that appears late in mitosis and is composed of intermediate filaments, microfilaments, and microtubules. Secretory vesicles are guided along the phragmoplast cytoskeleton toward the equatorial region of the structure where they coalesce and fuse to form a membranous tubular-vesicular network within which cell wall biosynthesis is initiated. A smoother more plate-like structure develops and extends radially outward as additional vesicles are added to the growing margin of the cell-plate until it ultimately fuses with the parental plasma membrane yielding two daughter cells separated by a common cell wall and extracellular space.
Three-Dimensional Visualization Of Miotic Chromosomes In Maize Trisomy 6
Authors: Cheng Wayne Y , Lee Thomas C , Walden David B , Cheng Ping-chin 
Published: July 2020

Abstract
The ability to visualize the chromosomes, especially in three-dimensional (3D) space, has great benefits for the understanding of genes’ function. The availability of various trisomic genotype in maize provides an excellent system for the study of 3D chromosome arrangement at various developmental stages. Laser scanning confocal microscopy and digital deconvolution technique is best suited for this type of work. A preliminary database on the three-dimensional arrangement of Ohio43 inbred line has been established; this information is essential for the evaluation of the effect of additional chromosome in trisomy genotypes.
Tassel inflorescence of maize (Zea mays L.) trisomy 6 in Ohio43 background were collected from the field station at the University of Western Ontario in London, Ontario, Canada, during the summer of 1998. Tassels at the proper developmental stages were fixed in 3:1 (95% EtOH / acetic acid) solution and stored at room temperature. After dissection from the spikelet, anthers were treated with the Feulgen-method, dehydrated in ethanol series and cleared in methyl salicylate.
Ultrastructural Analysis Of The Aseptate Gregarine Pterospora, A Parasite of The Bamboo Worm Axiothella Mucosa.
Authors: Landers Stephen C 
Published: July 2020

Abstract
The gregarine Pterospora is a parasite found in the body cavities of bamboo worms (Polychaeta: Maldanidae). The gamont stage of Pterospora has a bizarre structure with a main cell body and multiple posterior cytoplasmic extensions (Fig. 1). The cells are found in pairs within the coelom of the host and move by cytoplasmic streaming as they fill and empty their posterior extensions. Reports of this parasite in the literature are few (see references 1 & 2 for a review) and no ultrastructural details have been published regarding the genus. This study examines the fine structure of the gamont stage with particular emphasis on the structure of the pellicle.
The maldanid worm Axiothella mucosa was collected by shovel in St. Andrew Bay, Florida and returned to the Troy State University campus. Pterospora spp. gamonts were pipetted from minced setigers of the worms and fixed in 3% glutaraldehyde buffered with 0.05M sodium cacodylate, pH 7.5, for 1-6 hours.
Tissue Response To Three Mixtures Of A Bone Substitute Material In Tooth Extraction Sites
Authors: Krizan K E , Lew D , Burton R , Laffoon J , Keller J C 
Published: July 2020

Abstract
The objective of this study was to evaluate the biological responses of three different mixtures of a bone substitute material placed in tooth extraction sites to determine which mixture best enhances bone formation. Under general anesthesia three adult mongrel canine had bilateral extractions of the second and fourth premolar bicuspids. Each site was modeled into 3-wall defect with box-like dimensions and having the window on the buccal (outer) side of the mandible. A synthetic hydroxyapatite bone cement (HAC) was prepared three different ways: 1) 2.5 gms HAC + 0.75 cc sterile water (W); 2) 2.5 gms HAC + 0.75 cc 2% Hydroxypropylmethylcellulose in sterile water (HPMC); 3) 2.5 gms HAC + 0.75 cc Sodium Phosphate [45mM/15mL Phosphate + 60 MEq/15mL Sodium] (SP). Each mixture was syringe injected into a different extraction site and the fourth site received no cement to serve as a control site, and after sites were filled, a periodontal flap closure was accomplished with a 4-0 VICRYL suture.
Identification Of Scavenger Receptor Sr-Bi In The Endothelial Cells And The Smooth Muscle Cells Of Rat Aorta In Vitro
Authors: Yeh Y C , Hwang G Y , Yang V C 
Published: July 2020

Abstract
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 immunoblotting and immunofluorescence microscopy to study the expression and subcellular localization of SR-BI in the cultured endothelial cells and the smooth muscle cells of rat aorta.
A peptide containing residues 495 to 509 from mSR-BI plus an NH2-terminal cysteine was coupled to hemocyanin. Then the peptide was used to generate mSR-BI495 antiserum in New Zealand white rabbits. The cells from the aortic ring of 1-month-old Spraque-Dawly rats were grown in the dishes containing complete medium (Dulbecco's modified Eagle's medium with 10% fetal bovine serum) and incubated at 37°C in 95% air/ 10 % CO2 atmosphere for 3-4 days.
Electron Tomography of Swollen Rigor Fibers of Insect Flight Muscle Reveals the S2 Fragment of Myosin
Authors: Wang Yunxun , Winkler Hanspeter , Reedy Michael K , Reedy Mary C , Taylor Kenneth A 
Published: July 2020

Abstract
We have used electron tomography of rigorized fibers of insect flight muscle swollen by immersion in dilute buffer (†1mM MOPS, pH 6.8), to reveal the 3-D arrangement of the myosin S2 fragment for the first time. S2 is an α-helical coiled-coil structure that connects the myosin head to the thick filament backbone. It is usually invisible in electron micrographs because of its close proximity to the backbone. The increase in inter-thick filament spacing from 45 nm to 55 nm pulls the S2 away from the filament backbone making it easier to identify. A total of 4 tomograms have been calculated by our standard method which involves collecting images using non-uniformly spaced tilt angles, cross correlation alignment, area matching and Whittaker-Shannon interpolation of the 3-D transform. A projection of one of these tomograms is shown in Figure 1. in raw tomograms S2 appears as a rod-like structure that originates at the thick filament surface to connect to both lead and rear crossbridges of rigor. S2 segments are particularly well resolved at the ends of the thick filament (Fig. 2), where in some cases it appears that the myosin subfilaments are separated from the backbone. Both the azimuthal direction and axial angle of S2 are variable.