bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three-dimensional imaging of the living eye
Authors: Masters Barry R. 
Published: June 2020

The structure of the in situ rabbit cornea can be observed at high resolution and contrast with reflected light confocal microscopy. In vivo confocal images of the living cornea have been made at lower resolution and lower contrast using a SIT video camera together with a real-time Nipkow disk confocal microscope adapted for in vivo observations. This paper describes the three dimensional reconstruction of the in situ cornea from an enucleated rabbit eye with confocal reflected light microscopy and volume rendering computer techniques.A laser scanning confocal microscope (BioRad MRC 600) was used in the reflected light mode to obtain the two-dimensional image stack from the cornea of a freshly enucleated rabbit eye. The eye was maintained in a physiological state with aerated Ringer's solution. The light source was an argon ion laser with a 488 nm wavelength. The microscope objective was a Leitz X25, NA 0.6 water immersion lens. The 400 micron thick cornea was optically sectioned into 133, three micron sections. The optical sectioning was performed perpendicular to the optical axis of the eye globe.
Kalinin: A new epithelial basement membrane adhesion molecule
Authors: Keene Douglas R. , Lunstrum Gregory P. , Rousselle Patricia , Burgeson Robert E. 
Published: June 2020

A mouse monoclonal antibody produced from collagenase digests of human amnion was used by LM and TEM to study the distribution and ultrastructural features of an antigen present in epithelial tissues and in cultured human keratinocytes, and by immunoaffinity chromatography to partially purify the antigen from keratinocyte cell culture media.By immunofluorescence microscopy, the antigen displays a tissue distribution similar to type VII collagen; positive staining of the epithelial basement membrane is seen in skin, oral mucosa, trachea, esophagus, cornea, amnion and lung. Images from rotary shadowed preparations isolated by affinity chromatography demonstrate a population of rod-like molecules 107 nm in length, having pronounced globular domains at each end. Polyacrylamide gel electrophoresis suggests that the size of this molecule is approximately 440kDa, and that it is composed of three nonidentical chains disulfide bonded together.
Expression of laminin and beta-1 integrin in embryonic, neonatal, and adult rat heart
Authors: Price R.L. , Borg T.K. , Terracio L. , Nakagawa M. 
Published: June 2020

Little is known about the temporal expression of extracellular matrix components (ECM) and its receptors during development of the heart. Recent reports have shown that ECM components undergo both qualitative and quantitative changes during development, and it is believed that ECM components are important in the regulation of cell migration and cell:cell and cell:ECM recognition and adhesion.Integrins are transmembrane glycoproteins which bind several ECM components on their external face and cytoskeletal elements on the cytoplasmic face. Laminin is a basement membrane component which has been recognized as an important site for cell adhesion. Both the integrins and laminin are expressed early in development and continue to be expressed in the adult heart. With their documented roles in cell recognition, and cell:cell and cell:ECM migration and adhesion these proteins appear to be important components in development of the heart, and their temporal expression may play a pivotal role in morphogenesis and myofibrillogenesis of the heart.
A study of fibrin clot structure under various ionic conditions using stereoscopic IVEM images
Authors: Baradet T. , Weisel J.W. , Peachey L.D. 
Published: June 2020

Fibrin clots are formed by the conversion of fibrinogen into fibrin monomers which assemble to produce two-stranded protofibrils that aggregate to form fibers. These fibers may also aggregate laterally with other fibers to form larger fiber bundles. Investigations of fibrin clot structures under various ionic conditions using SEM showed dramatic differences in fiber morphology and clot structure. Fibrin clots formed under various ionic conditions were investigated by the examination of stereoscopic IVEM images. This technique provides greater depth discrimination and higher resolution images of clot ultrastructure. Details of fiber association and branching are of particular interest.Purified human fibrinogen was prepared at a concentration of 0.5 mg/ml in 0.4M, 0.2M, and 0.05M buffers (0.05M Tris-HCI, pH 7.4, with 2mM CaCl2). Fibrinogen solutions were mixed with thrombin to a final concentration of 0.3U/ml and aiiquots placed onto Formvar and carbon coated grids. After clotting for 1 hr. at room temperature, clots were fixed with 3% glutaraldehyde in 0.1 M Na-cacodylate buffer, pH 7.2, for 5 min. Grids were kept constantly moist to avoid collapse or syneresis.
Thylakoid membrane development in pigment-deficient wheat chloroplasts
Authors: Freeman Thomas , Duysen Murray , Eskins Ken , Guikema James 
Published: June 2020

The thylakoid membranes of higher plant chloroplasts contain at least two major pigment protein complexes, photosystem I (PSI), and photosystem II (PSII). The mature apoprotein of these complexes (involved in the initial reactions of photosynthesis) bind specific chlorophylls (Chl) and specific carotenoids in an unknown manner. It has been suggested, however, that the synthesis of pigments is normally coordinated with that of apoproteins. We have examined the effect of gabaculine (3-amino-2, 3-dihydrobenzoic acid) on granal thylakoid stacking as well as pigment and apoprotein accumulations for PSI and PSII in wheat.Gabaculine (0.5mM) was applied with nutrient solution to 6.5 day-old wheat seedlings maintained in a growth chamber at 23C. One seedling lot grown under continuous light (400 μmol photons s-1 m-2) possessed green primary leaves at time of treatment whereas another seedling lot, dark grown, possessed only etiolated primary leaves. Twelve hours after treatment, the etiolated seedlings were transferred into continuous light. The primary and secondary leaves were subsequently harvested from 14 day-old seedlings of both lots.
Occurrence of leucocytes in the intracellular granules in the enterocytes of the jejunum of newborn pigs
Authors: Kömüves Lászlo G. , Heath Julian P. , Nichols Buford L. 
Published: June 2020

In some mammals, where the transport of maternal immunoglobulins across the intestine plays an important role in the passive immunity of neonates (such as rat, pigetc), one of the most striking features of the enterocytes in the small intestinal mucosa of suckling newborns is the formation of large cytoplasmic granules shortly after birth. These large granules are believed to be represent specialized lysosomes and/or late endosomes and accumulate maternal immunoglobulins from the colostrum. Here we report our observation that different leucocytes can frequently be found in the subnuclear granules in suckling piglets.Suckling piglets of various age from three different litters were used in this study. Pieces of the jejunum were collected and processed for Spurr's and LR White embedding. Semithick section were observed with a Zeiss Axiophot microscope. Thin LR White sections were immunolabeled with a rabbit anti-porcine IgG, followed by goat anti-rabbit IgG, conjugated to 10 nm gold. Semithick LR White sections were silver intensified following immunolabeling. Thin sections were observed in a Philips CM 12 electron microscope at 80 kV.
Slit scan illumination for dynamic focusing
Authors: Benner G. , Frey J. , Weimer E. 
Published: June 2020

This mode describes a modification of the spot scan mode1 in which areas on a photographic plate are exposed one after the other using small illuminating spots. The spot scan mode in transmission electron microscopes (TEM) reduces specimen damage and specimen drift. In addition to this it allows dynamic focussing at high tilt angles of the specimen.High-resolution, 3-D specimen reconstruction and reflection electron imaging using specimen tilt angles of up to 90° require dynamic focussing rectangular to the tilt axis of the goniometer for imaging of off-axis specimen areas. A slit-type illumination of the specimen parallel to the goniometer tilt axis may provide a better solution for such types of problems.
In situ high-resolution Transmission electron microscopy of interphase boundary motion in metallic alloys
Authors: Howe James M. 
Published: June 2020

Information provided by in situ studies is often essential for understanding microstructural evolution in solids. The recent development of intermediate-voltage high-resolution transmission electron microscopes (HRTEM) with in situ heating capabilities now provides the opportunity to perform in situ high-resolution studies of interphase boundary (IPB) motion. This paper presents initial results on in situ HRTEM studies of IPB motion in metallic alloys, in particular, during growth of Q precipitates in an Al-Cu-Mg-Ag alloy and Pd3Si crystals in an amorphous Pd-Si alloy.Samples of an Al-4Cu-0.5Mg-0.5Ag (wt.%) alloy were aged for 24 hr at 250°C and electropolished in a HNO3/methanol solution; samples of an amorphous Pd80Si20 (at.%) ribbon were ion milled in a liquid-nitrogen cold-stage at 6 kV, 0.3 mA and 15° tilt. The samples were examined at 400 kV in a JEOL 4000EX microscope equipped with a UHP40X hot-stage pole piece and double-tilt holder at temperatures of 200-400°C. Images were recorded on a Sony BetaCam video cassette recorder connected to a Gatan fiber-optically coupled TV camera with an image intensifier. A 35 mm camera was used to obtain photographs directly from the TV monitor during playback of the video cassettes.
Resolution in x-ray microscopes
Authors: Jacobsen C. , Kirz J. , Williams S. 
Published: June 2020

X-ray microscopes can be roughly grouped into two categories: soft x-ray microscopes (λ ≈ 1-10 nm) which are able to image specimens at up to 30 nm resolution with some elemental mapping capabilities, and hard x-ray microprobes (E ≈ 3-100 keV) which are able to map trace chemical compositions and produce tomograms at ∼ 2 μm resolution. In both cases, the sample can be hydrated and in air, its thickness can be range from a few μm (with soft x rays) to a few mm (hard x rays), and the radiation dose delivered is considerably lower than what is involved in the equivalent electron microscopy technique.Some x-ray microscopes are lensless instruments. In contact microscopy and Gabor holography, soft x rays passing through the sample are recorded directly on high resolution photoresists (e.g., PMMA). Shinozaki et al. have studied the x-ray exposure properties of PMMA in detail, and have concluded that a detector resolution limit of 20 nm or better should be attainable.
A Monte Carlo calculation of the x-ray production from multilayer samples
Authors: Ly T. D. , Howitt D. G. 
Published: June 2020

The X ray generation and absorption from a sample in an SEM or Electron Microprobe depends upon the geometry as well as the composition. Various schemes for calculating the X-ray signal from a homogeneous sample have been developed but few have addressed the problem associated with the presence of distinct microstructures. We have developed a Monte Carlo program to calculate the signal production from a multilayer sample as a first step to the incorporation of microstructural effects.The X-ray production from a layered structure is different from a homogeneous sample because the signal production and absorption are discontinuous. The differences can be calculated if the layer thicknesses and positions can be taken into account. The principle behind the calculation we have undertaken is the continuously monitor the energy and position of the electron in the specimen. Each trajectory is calculated in the usual stepwise manner except that the step size and scattering probability are continuously adjusted to accommodate the scale of the microstructure.
High-resolution electron microscopy study on the interface of electrogalvanized coatings on sheet steel after heating
Authors: Lin Yuli , Chiou Wen-An , Meshii M. 
Published: June 2020

Fe-Zn alloy coatings on sheet steel have been widely used by automobile industry due to their superior corrosion resistance and manufacturability. In order to investigate the interface structure between various phases in the Fe-Zn system and their crystallographic relations, steel sheets coated with electrogalvanized pure zinc were heat-treated at various temperatures and the resulting structures were examined in HREM with special attention to the formation of brittle Fe-Zn intermetallic phases.Due to extreme difficulties in preparing cross-sectional TEM specimens from a thin Zn-based coating, little microstructural information is currently available for the interfacial region. A special technique was developed to overcome these difficulties in the present investigation. Instead of using the epoxy on the sandwiched specimens, as commonly adopted to prepare cross-sectional TEM specimens in electronic and photonic devices, 3mm of pure zinc was electrodeposited on top of the coating (15 μm) to be examined.
Characterization of carbides in M50NiL
Authors: Lin L. S. , Gumz K. P. , Karg A. V. , Law C. C. 
Published: June 2020

Carbon and temperature effects on carbide formation in the carburized zone of M50NiL are of great importance because they can be used to control surface properties of bearings. A series of homogeneous alloys (with M50NiL as base composition) containing various levels of carbon in the range of 0.15% to 1.5% (in wt.%) and heat treated at temperatures between 650°C to 1100°C were selected for characterizations. Eleven samples were chosen for carbide characterization and chemical analysis and their identifications are listed in Table 1.Five different carbides consisting of M6C, M2C, M7C3 and M23C6 were found in all eleven samples examined as shown in Table 1. M6C carbides (with least carbon) were found to be the major carbide in low carbon alloys (<0.3% C) and their amounts decreased as the carbon content increased. In sample C (0.3% C), most particles (95%) encountered were M6C carbide with a particle sizes range between 0.05 to 0.25 um. The M6C carbide are enriched in both Mo and Fe and have a fee structure with lattice parameter a=1.105 nm (Figure 1).
Observations of surface structures and reaction products for materials exposed in space in low-earth orbit
Authors: Quinones Stella , Advani A.H. , Marquez Benito , Rivas Jesus , Miglionico C. , Murr L.E. , Fisher W.W. , Arrowood R. 
Published: June 2020

A preliminary study of materials exposed in space in low-earth orbit for nearly six years (in the NASA Long-Duration Exposure Facility (LDEF)) has revealed a range of micrometeorite and microparticle impact craters and blisters of unknown origin on aluminum alloy 6061-T6 samples on the leading edge of the satellite. In addition these samples were covered with an enormous range of reaction products which included crystals and polycrystalline aggregates which originated in part from other reactions and atomic oxygen degradation taking place in systems proximate to the alloy samples.A replication-type lift-off techniques was developed to remove reaction products (crystals and polycrystals, etc.) and debris from the specimen surfaces in order to isolate them from the background substrate without creating microchemical or microstructural artifacts. This technique culminates in extracted surface features resting on a carbon support film which is virtually “invisible” to observation by electron microscopy and non-dispersive x-ray analysis.
Electron holography of frozen-hydrated biological specimens
Authors: Matsumoto T. , Osakabe N. , Endo J. , Matsuda T. , Tonomura A. 
Published: June 2020

Electron holography has been applied to a variety of field, in which the reconstructed phase information was effectively used to elucidate many important natures of materials. Applications of electron holography to biological specimen, however, has not been developed yet. We report here an application of electron holography of frozen-hydrated biological specimen, which is observed by electron holography for the first time.An electron microscope(Hitachi HU-12A) equipped with a 100-kV cold field emission gun was used for the experiment. Catalase crystals were embedded in amorphous ice by quick-freezing and the grids were transferred to the microscope using Gatan cryo transfer system. A specially designed low-dose imaging system for the microscope was devised and used to record holograms.
Temperature effects on orientation-dependent Exelfs
Authors: Thiel Brad L. , Viney Christopher 
Published: June 2020

Recently, investigations have begun to explore the effects of Mean-Square-Relative-Displacements (MSRD), or thermal damping, on the EXELFS oscillations above electron absorption edges. These types of analysis can be extended to include orientation effects in anisotropic crystal systems. Furthermore, as this technique is a direct probe of the electronic structure of a crystal, this information could be combined with the crystal symmetry and Cauchy relations to examine various physical properties. One such property is the elastic compliance quadric.With the development of the parallel detection EELS spectrometer, EXELFS type studies have become practical. This makes accessible a large field of analysis, previously explored only by EXAFS. Thus, we are able to combine a wealth of experimental and data analysis algorithms from that technique with the high spatial resolution and crystallographic information afforded by the modern analytical TEM. We have developed computer simulation programs which demonstrate the feasibility of this hybrid analysis.
Application of electron energy loss spectroscopy to microanalysis of irradiated stainless steels
Authors: Kenik E. A. , Bentley J. , Evans N. D. 
Published: June 2020

Energy dispersive X-ray spectroscopy (EDXS) has limited application to microanalysis of radioactive materials because of degraded detector performance and the “intrinsic” spectrum associated with the radioactive decay. Electron energy loss spectroscopy (EELS) is not affected by specimen radioactivity and also offers the possibility of improved spatial resolution. Measurements of radiation-induced segregation (RIS) in irradiated stainless steels have been made by both techniques. Analytical electron microscopy was performed at 100 kV in a Philips EM400T/FEG, equipped with an EDAX 9100/70 EDXS system and a Gatan 666 parallel detection EELS (PEELS). Microanalysis was performed in the STEM mode (<2-nm-diam probe with >0.5 nA) with the same acquisition time (50 s) used for both techniques.Initial measurements were performed on an ion-irradiated modified type 316 stainless steel (designated LS1A), which had moderate-width (∼20 nm) RIS profiles at grain boundaries. Profiles measured by EDXS and PEELS match well and show chromium depletion and nickel enrichment (Fig. 1).
Magnetic force microscopy
Authors: Grütter P. , Rugar D. , Mamin H.-J. , Albrecht T.R. 
Published: June 2020

The aim of this talk is to give a short introduction to the technique of magnetic force microscopy (MFM), review recent advances in instrumentation and present measurement on various magnetic materials.MFM [1, 2] is a non-destructive method which allows the imaging of magnetic structures with little or no sample preparation on a 50-100 nm scale. The central component of every MFM is a sharp magnetic tip mounted on a flexible cantilever. The interaction of the magnetic tip with a sample stray field leads to a change of both cantilever deflection and resonant frequency. These changes are measured with a sensitive displacement probe, eg. an interferometer. Images are generated by raster scanning the sample relative to the tip and recording the tip-sample interaction as a function of position.
Novel magneto-optical recording materials: Bi-substituted garnet films
Authors: Suzuki Takao , Nuri Hossein 
Published: June 2020

For future high density magneto-optical recording materials, a Bi-substituted garnet film ((BiDy)3(FeGa)5O12) is an attractive candidate since it has strong magneto-optic effect at short wavelengths less than 600 nm. The signal in read back performance at 500 nm using a garnet film can be an order of magnitude higher than a current rare earth-transition metal amorphous film. However, the granularity and surface roughness of such crystalline garnet films are the key to control for minimizing media noise.We have demonstrated a new technique to fabricate a garnet film which has much smaller grain size and smoother surfaces than those annealed in a conventional oven. This method employs a high ramp-up rate annealing (Γ = 50 ~ 100 C/s) in nitrogen atmosphere. Fig.1 shows a typical microstruture of a Bi-susbtituted garnet film deposited by r.f. sputtering and then subsequently crystallized by a rapid thermal annealing technique at Γ = 50 C/s at 650 °C for 2 min. The structure is a single phase of garnet, and a grain size is about 300A.
Diffraction theory of phonon-scattered electrons
Authors: Wang Z. L. 
Published: June 2020

Electron-phonon interactions are inelastic scattering processes in high-energy electron diffraction, and are responsible for thermal diffuse scattering (TDS). The atomic thermal vibrations introduce a small time-dependent perturbation to the crystal potential(1)where is the displacement of the atom (at position within the hth unit cell (position R(h)) from its equilibrium position,(2)
TEM characterization of silicon epitaxial layer grown on Si-TaS2, eutectic composites
Authors: Sung C.M. , Levinson M. , Tabasky M. , Ostreicher K. , Ditchek B.M. 
Published: June 2020

Directionally solidified Si/TaSi2eutectic composites for the development of electronic devices (e.g. photodiodes and field-emission cathodes) were made using a Czochralski growth technique. High quality epitaxial growth of silicon on the eutectic composite substrates requires a clean silicon substrate surface prior to the growth process. Hence a preepitaxial surface cleaning step is highly desirable. The purpose of this paper is to investigate the effect of surface cleaning methods on the epilayer/substrate interface and the characterization of silicon epilayers grown on Si/TaSi2substrates by TEM.Wafers were cut normal to the <111> growth axis of the silicon matrix from an approximately 1 cm diameter Si/TaSi2composite boule. Four pre-treatments were employed to remove native oxide and other contaminants: 1) No treatment, 2) HF only; 3) HC1 only; and 4) both HF and HCl. The cross-sectional specimens for TEM study were prepared by cutting the bulk sample into sheets perpendicular to the TaSi2fiber axes. The material was then prepared in the usual manner to produce samples having a thickness of 10μm. The final step was ion milling in Ar+until breakthrough occurred. The TEM samples were then analyzed at 120 keV using the Philips EM400T.
A SIMS-TEM study of fluorine implants and anneals into silicon and polysilicon
Authors: Kaushik Vidya S. , Hance Robert L. , Tseng Hsing-H. , Tobin Philip J. 
Published: June 2020

The behavior of fluorine in silicon is important for VLSI applications. The presence of fluorine can lead to improved gate oxide interface reliability and to enhanced boron diffusion in BF2 implanted devices. We have therefore studied the diffusion behavior of fluorine in silicon and polysilicon using coupled SIMS and TEM investigations on samples implanted with fluorine alone.Fluorine was implanted into a) (100) silicon and b) polysilicon layers to a dose of 1 x 1016/cm2 at 60 keV at room temperature. The polysilicon layers were grown by LPCVD at 635°C, resulting in small grained columnar polysilicon. The polysilicon layers had a 50 nm grown oxide layer between the polysilicon layer and the (100) silicon substrate. After the fluorine implants, the wafers were subjected to annealing at 750-950°C for 30 minutes. All the wafers were capped with a 13 nm silicon dioxide layer at the wafer surface prior to the ion implantation. SIMS analysis was performed on a Cameca IMS-3F spectrometer with 10 keV O2+ ions. XTEM images were obtained on a JEOL 2000 FXII operated at 200 keV with the electron beam parallel to the <110> silicon zone axis.