bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light and Electron Microscope Immunohistochemical Localization of Decorin and Biglycan in Osteoblasts and Early Bone Matrix of Developing Rat Bone.
Authors: Yamada T , Ono Y , Lee I , Ikeda T , Takagi M 
Published: July 2020

Abstract
Decorin and biglycan are the predominant proteoglycans (PGs) isolated from bone of several animal species. Previous light microscope (LM) immunohistochemical studies of fetal human bone demonstrated that osteoid and osteoblasts reacted with both biglycan and decorin antibodies, but min-eralized matrix did not; however, the precise distribution of immunostaining was not examined at the electron microscope (EM) level. The present study examines LM and EM immunolocalization of decorin and biglycan in osteoblasts and early bone matrix of developing mandible of fetal rats, using polyclonal antibodies (LF113, LF106) directed against synthetic peptides corresponding to nonho-mologous regions of the two core proteins.
Fetuses were collected at embryonic day 15-18 from pregnant Wistar rats. After aldehyde fixation, developing jaws with and without osmium post-fixation were dehydrated, and embedded in paraffin, Spurr's resin, or LR gold resin for morphological and immunohistochemical observations. Sections cut from paraffin- or LR gold resin-embedded specimens were immunostained with LF113 specific for rat decorin or LF106 specific for rat biglycan, which were kindly provided by Dr. L.W. Fisher, National Institute of Dental Research, NIH, Maryland.
The Nature and Distribution of Large Proteoglycans in Developing Rat Bone.
Authors: Lee I , Ono Y , Kubushiro N , Ikeda T , Takagi M 
Published: July 2020

Abstract
The nature and distribution of large hyaluronate-binding proteoglycans (PGs) in early bone formation bf developing rat mandible were biochemically and immunohistochemically investigated with a monoclonal antibody (MAb) 5D5, which is derived from bovine sciera and specifically recognizes the core protein of the large PGs such as versican, neurocan and brevican, but not that of aggrecan.
The first sign of mandibular bone formation is evident in the embryonic day 15 (Day 15). At the site of initiation of bone formation, a center of ossification was seen in the close proximity to Meckel’s cartilage. At the light microscopic level, these centers contained fine strips of the intercellular matrix surrounded by osteoblasts (Fig. 1). At the EM level, these matrices contained very fine fibrillar material, numerous, osteoblastic cell processes, and vesicular structures, but did not show any typical mineralization pattern. In Day 16, clusters of needle-like crystals or bone nodules, which varied considerably in size and shape, were seen in the intercellular matrix among osteoblasts (Fig. 2).
Light and Electron Microscope Immunohistochemical and Biochemical Studies of Vitronectin in Developing Rat Bone.
Authors: Takagi M , Kumagai T , Lee I , Ono Y , Maeno M 
Published: July 2020

Abstract
Recently, Seiffert using light microscope (LM) immunohistochemical methods, has localized vitronectin (Vn) in the mineralized bone matrix of mature mouse long bone after demineralization with 10 % nitric acid, indicating that Vn is a specific component of bone tissue. This raises the possibility that Vn is involved in regulation of bone metabolism. The present study extends previous studies to the electron microscope (EM) level and utilizes biochemical methods to determine the distribution and nature of Vn in early bone formation of developing rat mandible with rabbit antimurine Vn IgG (antiVn).
Developing jaws of fetuses were collected at embryonic day 15-18 from pregnant Wistar rats. After al-dehyde fixation, specimens with and without osmium post-fixation were dehydrated, and embedded in paraffin, Spurr's resin, or LR gold resin for morphological and immunohistochemical observations. Sections cut from paraffin- or LR gold resin-embedded specimens were immunostained with antiVn, which was kindly provided by Dr. D. Seiffert, The Scripps Research Institute, La Jolla, California.
Spectral Karyotyping
Authors: Ried Thomas , Macville Merryn , Manoir Stan du , Veldman Tim , Weaver Zoe , Liyanage Marek , Schröck Evelin 
Published: July 2020

Abstract
In human leukemia and solid tumors cytogenetic analysis provides critical information of diagnostic and prognostic importance. Frequently however, the unambiguous characterization of all aberrant chromosomes is difficult using conventional chromosome banding techniques alone. We have developed a novel approach, termed spectral karyotyping (SKY), based on the hybridization of 24 differentially labeled human chromosome painting probes that allows the simultaneous color identification of all human chromosomes. This genome scanning method combines Fourier spectroscopy, CCD-imaging, and optical microscopy to visualize the hybridization of differentially labeled chromosomes painting probes. One of the most important analysis algorithms is the spectral-based classification algorithm that enables multiple different spectra in the image to be identified and highlighted in classification-colors. This allows assignment of a specific classification-color to all human chromosomes based on their spectra. This algorithm assumes that the (reference) spectrum of each chromosome has been measured and stored in a reference library in the computer
Actin Dynamics and Force Generation in the Motility of Listeria Monocytogenes
Authors: Fung David C , Theriot Julie A 
Published: July 2020

Abstract
The gram-positive bacterium Listeria monocytogenes is one of several intracellular pathogens which can move about within its host's cytoplasm using a form of actin-based motility. This motility plays an important role in the virulence of the microbe, which can cause serious disease in humans. Actin is a host-cell protein whose polymerization is required for the locomotion of animal cells. L. monocytogenes exploits this normal cellular machinery for its own movement by creating a “comet” tail of cross-linked actin filaments behind it. Actin polymerization occurs at the bacterial surface and is required to drive the bacterium forward.
We are interested in how L. monocytogenes induces the polymerization of actin and how this polymerization can lead to the generation of force. To study this, we have used time-lapse videomicroscopy and a cell-free system derived from Xenopus egg extracts. We have observed rare instances of a saltatory movement of L. monocytogenes in these extracts.
Probing The Mechanisms Underlying Kinetochore Behavior In Vertebate Cells Using Combinations of Advanced Light and 3-D Electron Microscopy
Authors: McEwen B F , Heagle AB , Rieder CL 
Published: July 2020

Abstract
For daughter cells to receive equal copies of the genome during mitosis, the replicated chromosomes must attach to and move bi-directionally on the mitotic spindle. A chromosome becomes attached to the spindle via a pair specialized structures, known as kinetochores, that are positioned on opposite sides of its primary constriction (one on each of the two chromatids). In addition to being the spindle attachment site, kinetochores are also involved in producing and/or transmitting the forces for chromosome motion. In vertebrates the kinetochore closest to a spindle pole at the time of nuclear envelope breakdown usually is the first to attach to the spindle. As a result of this attachment the now “monooriented” chromosome moves toward the closest pole where its only attached kinetochore initiates oscillatory motions toward and away from that pole until the unattached sister kinetochore acquires microtubules (Mts) from the opposite spindle pole.
Electron Tomography of Rat-Liver Mitochondria: Structure of Cristae and Interactions With Endoplasmic Reticulum
Authors: Mannella CA , Buttle K , Tessitore K , Pixley S , Rath B , D’Arcangelis D , Marko M 
Published: July 2020

Abstract
We are using electron tomography to investigate the internal organization of mitochondria and the interactions of these organelles with other cellular components. Two-axis tilt-series are recorded from 0.2-1.0-μm sections using either an AEI EM7 high-voltage or JEOL 4000 intermediate-voltage electron microscope. Reconstructions are computed using programs in SPIDER and visualized with the Sterecon system.
Three-dimensional reconstructions of conventionally fixed and plastic-embedded rat-liver mitochondria (isolated and in situ) indicate that the cristae, the infoldings of the inner membrane, are pleiomorphic, defining compartments that are connected to each other and to the surface of the inner membrane by narrow (30-40-nm diameter) tubular regions (Fig. 1). This is contrary to the “baffle” model commonly shown in textbooks and has important implications for the diffusion of ions, metabolites, and macromolecules inside the organelle. The same basic organization is also observed in reconstructions of mitochondria in rat-liver sections prepared by the cryo-fixation method of Tokuyasu(Fig. 2).
Three-Dimensional Structure of the Gap Junction Connexon and Intercellular Channel
Authors: Perkins Guy , Goodenough Dan , Sosinsky Gina 
Published: July 2020

Abstract
Gap junctions are specialized cell-cell contact areas by which cells communication with each other. Within these contact areas are tens to thousands of membrane channels. A gap junction membrane channel (also referred to as an intercellular channel) is unique among membrane channels in that it is composed of two oligomers with each of two adjacent tissue cells contributing one oligomer (called a connexon or hemichannel). The pore of the intercellular channel controls the passage of small molecules and ions from one cell to another.
We are interested in how the structure and surface topology of the gap junction connexon at its extracellular surface influences the docking and formation of an intercellular communicating channel. It has been demonstrated that connexons made from some connexins will dock and form functional channels with some but not all connexons made from other isoforms. This selectivity is surprising considering that the primary sequences of the docking domains are highly conserved.
Scanning Electron Microscopic Study of Erythroblastic Islands Obtained by “Spleen-Stamp Culture” Method
Authors: Fujii Y , Terada N , Ueda H , Baba T , Ohno S 
Published: July 2020

Abstract
During hematopoiesis of mammalian animals, an erythroblastic island in the bone marrow has been reported to contain a central macrophage surrounded by many erythroblasts. Fetal mouse livers and spleens, which are treated with collagenase, have been used to get the erythroblastic island in tissue cultures. In this study, we have cultured some stamped cells obtained from spleens of anemic mice and examined their structures by scanning electron microscopy.
Hemolytic anemia of female BALB/c mice was induced by acetylphenylhydrazine (4mg/g body weight) injection for 5 days. Spleens were resected on the second day after the last injection and a “spleen-stamp culture“ method was performed. Briefly, they were cut with razor blades (Fig. 1a) and splenic cells on the cut tissue surface were stamped on collagen-coated coverslips (Fig.1b). The stamped splenic cells were covered with dialysis membranes (Fig. 1c). They were cultured with 55% IMDM, 20% L-15 and 25% FBS, containing 2U/ml erythropoietin (EPO) in humidified atmosphere of 5% CO2 at 37°C for 1-3 days.
Microcontact Printed Substrates for Growing Central Nervous System Neurons and Glia
Authors: Craighead H G , Isaacson M , John P St , Davis R , Banker G , Esch T , Kam L , Shain W , Turner J N 
Published: July 2020

Abstract
The application of nano- and microfabrication to biology is an emerging area linking engineering and biology. We are using microfabrication techniques to make patterns of specific bioactive molecules on glass and silicon surfaces to study central nervous system neurons and glia. Cell adhesion and tissue reaction to implanted silicon based electronic prosthetic devices are being studied, and the methods expanded to interface neurons with integrated circuits to study their electrical properties. The number, type and distribution of cells adhering to particular portions of a substrate can be influenced by patterning amine groups, proteins or polypeptides. We are using microcontact printing as an alternative to lithography for chemical patterning.
Primary cultures of rat cortical astrocytes and hippocampal neurons, and continuous cultures of transformed astrocytes were prepared on microcontact printed patterns produced by an elastomer stamp made from a silicon master. Fig. 1 shows two such patterns prepared by depositing self-assembled monolayers of N1[3-(Trimethoxylsily)propyl] diethylenetriamine (DETA) and octadecyltrichlorosilane (OTS).
How Multiphoton Excitation can Illuminate Biophysics
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Webb W W 
Published: July 2020

Abstract
Multiphoton molecular excitation by the strongly focused femtosecond pulses of infrared light generated as an 80 MHZ pulse train by a mode locked laser provides intrinsic submicron three dimensional spatial resolution of fluorescence excitation and photochemistry for laser scanning fluorescence microscopy. Because two-photon excitation requires simultaneous (∼10-16 seconds), absorption of two-photons focused laser intensities of about 1022 photons/cm2s are required. Since the rate of absorption is proportional to the square of the intensity, excitation is limited to the focal volume and is negligible elsewhere along the double cone of the focused illumination. Therefore, out of focus photodamage and fluorescence are generally negligible and laser scanning fluorescence microscopy with multiphoton excitation is intrinsically three dimensionally resolved with no out of focus background. Since the appropriate wave lengths are infrared for multiphoton excitation of ultraviolet or visible absorbing molecules, out of focus photodamage is eliminated. This allows imaging of useful ultraviolet absorbing indicators, vital DNA stains and autofluorescence in living cells with minimal, but not necessarily negligible, photodamage.
Quantitative Analysis of Coronary Atherosclerosis by Intra Vascular Ultrasound
Authors: Vince D G , Shekhar R , Cothren R M , Nissen S E , Tuzcu E M , Cornhill J F 
Published: July 2020

Abstract
Traditional methods for studying human coronary artery disease have significant limitations. Angiography allows evaluation only of the geometry of the remaining lumen; it cannot provide information on the structural or cellular composition of the arterial wall, which is essential to understand the processes involved in the progression of atherosclerosis. Intravascular ultrasound (IVUS) imaging is a new technology that permits tomographical visualization of a cross section through the vessel wall (Fig 1 A.) The development and refinement of IVUS has provided a powerful in vivo method to assess plaque morphology. Recent clinical studies have documented its sensitivity in detecting atherosclerosis, and it is increasingly employed to assist in selecting an appropriate therapeutic intervention. Perhaps more importantly, the potential of IVUS to quantify the structure and geometry of normal and atherosclerotic coronary arteries will allow one to characterize specific lesions and to differentiate the plaques that lead to various clinical syndromes. This study presents a three-dimensional (3D) reconstruction technique suitable for clinical use that accurately preserves 3D geometric information throughout the cardiac cycle without requiring mechanical IVUS catheter withdrawal aids.
Application of Multiphoton Imaging to Study of the Vasculature.
Authors: Zipfel Warren R , Williams Rebecca M , Watt W 
Published: July 2020

Abstract
Nonlinear or multiphoton fluorescence microscopy utilizes the simultaneous absorption of two (or three) longer wavelength photons to excite fluorophores (Denk et.al., 1990). For example, UV absorbing fluorophores such as DAPI or lndo-1 are excited using 700 nm near infrared light rather than 350 nm UV excitation. This relatively new form of laser scanning fluorescence microscopy has excellent optical sectioning capabilities in thick, highly scattering tissues. The high degree of intrinsic optical sectioning arises from the spatial nature of the excitation dependence, rather than from a confocal aperture or deconvolution algorithm. The fluorescence arising from any point in the specimen depends on the second or third power of the intensity (i.e. two and three photon excitation, respectively). This squaring (or cubing) of the illumination point spread function effectively confines the excitation to a tenth of a femtoliter optical volume when using a high NA lens. 680 to 1100 nm mode-locked lasers producing pulses of 100 femtosecond duration at a repetition rate of 80 Mhz are used to efficiently produce fluorescence excitation at average powers that are usually in the 0.5 to 10 mW range at the sample.
Quantitative Evaluation of a Standard for Immunogold Labeling of Collagen Type IV
Authors: Springe MJ , Hann CR , Johnson DH 
Published: July 2020

Abstract
Quantitative gold labeling studies allow the comparison of tissue antigens only if labeling conditions are the same. When labeling conditions deviate slightly, the labeling efficiency can also shift. Labeling efficiency can be determined on a standard containing known concentrations of the target antigen. When labeling this standard, the labeling density (LD) divided by the antigen concentration (C) gives the labeling efficiency (LE).(l) If the assumption is accepted that labeling efficiency is the same over the standard and tissue, then the antigen concentration in the tissue can be calculated from the labeling density. In this study, a labeling standard was constructed that contained collagen type IV in five concentrations and a blank agarose gel. Our design criteria specified that these six gels measure less than 2 mm across and the zones between protein concentrations be clearly delineated.
The labeling standard was constructed by diluting lyophilyzed collagen type IV in water to final concentrations of 1,2,3,4, and 5 mg/ml.
Exhaustive Photon Reassignment™: A Method Offering Enhanced Sensitivity and Quantitative Accuracy for High Resolution Fluorescence Microscopy
Authors: Kramer Jennifer A , Moorthy Ramkumar K , Casavan William N , Hitrys David C 
Published: July 2020

Abstract
Confocal microscopy is a technique that allows researchers to obtain a highly resolved, high-contrast image of a focal plane in a fluorescent specimen by excluding or rejecting light emanating from out-of-focus planes. However, the basic design of confocals results in limitations for many biologists. It is often difficult to avoid photobleaching of specimens, to visualize fine or faintly-labeled structures, or to acquire high-quality images using short exposure times. The photomultiplier tubes used as the amplification detectors in these systems are restricted to a dynamic range of 8 bits (255 intensity levels), produce noise, and are not quantitatively linear detectors.
Members of the Biomedical Imaging Group at the University of Massachusetts Medical School in Worcester, MA have spent the last fifteen years developing and perfecting a digital imaging system that helps scientists overcome these problems. Scanalytics is the exclusive worldwide licensee of this patented technology which allows researchers to obtain high-resolution, quantitatively accurate three-dimensional images of fluorescent specimens
Structure-Property Relationships in Sputtered Magneto-Optic Multilayers
Authors: Sinclair R , Bertero G A , Visokay MR 
Published: July 2020

Abstract
One technology for high-density information storage employs magneto-optic thin films. Key material properties include a large magneto-optic Kerr rotation of polarized light (especially in the blue wavelength range), high perpendicular magnetic anisotropy, good reflectivity and a large magnetic coercivity. These can be achieved in nano-scale magnetic multilayers (e.g., Co-Pt) in which one of the constituent layers is ferromagnetic. Naturally the magnetic properties can be manipulated to a great extent by the preparation conditions, and the microstructure is most readily revealed by cross-section high-resolution electron microscopy (HREM). In our work, extremely high quality multilayers were fabricated by sputtering using a variety of inert gases, and most notably the influence of interface sharpness on properties was assessed. Intermetallic compounds, which are essentially “natural” multilayers, were also extensively studied.
Figure 1 shows magneto-optic Kerr rotation hysteresis loops for multilayers sputtered in 5 mtorr of either argon or the heavier xenon gas.
HRTEM Study of Nanostructure of Co/Au Multilayers
Authors: Liu Y , Robertson BW , Shan ZS , Sellmyer D J 
Published: July 2020

Abstract
Multilayer thin films of Co/Au with large magnetic anisotropy are attracting strong interest. Among the factors affecting the film properties are the layer thicknesses of the Au layer and the Co layer. This paper reports the detailed HRTEM study of the nanostructure evolution of Co/Au films as a function of the Au thickness. Two DC-magnetron sputtered films with the same Co thickness 5Å but different Au thicknesses (Au60Å/Co5Å)x9/Au400Å (denoted Au60) and (Au10Å/Co5Å)x50/Au400Å (denoted Au 10) were chosen for detailed study. The Au60 film shows a well defined perpendicular magnetization loop with loop squareness S=l and an anisotropy value of 3xl06erg/cm3 while the Au 10 film shows an irregular perpendicular magnetization loop with S=0 and an anisotropy value of 1.5xl06erg/cm3.
For cross sectional TEM samples, bright field TEM images show that the grain size of the Au underlayer is about 20-80 nm. Slight convex curvature of the multilayers is observed.
HRTEM of Initial Oxidation of Carbon Nanotube Tips
Authors: Lordi V , Yao N 
Published: July 2020

Abstract
High resolution transmission electron microscopy (HRTEM) and diffraction technique, with their high sensitivity to small variations in periodic structure or lattice imperfections within individual crystals, have made it possible to relate nanostructure to physical properties of individual fullerenes(C60, C70, etc.) and carbon nanotubes. Using HRTEM imaging, in tandem with dynamic image simulation, we have examined the etching patterns of carbon nanotubes in terms of tip geometry and bond strains. Our studies indicate that the progression of oxidation is not random, and is fully determined by the tip structure, of which only a finite number of classes exist. Oxidation of carbon nanotubes prefers to start at the positions which are most strained, which is associated with the arrangement of pentagons.
Carbon nanotubes were synthesized using the carbon arc method similar to that used for the synthesis of fullerences. The carbon nanotubes are often capped by carbon shells that fit continuously on the ends of the long cylinder
TEM Study of Nanocrystalline AgxNi1-x Solid Solutions
Authors: Chiou W A , Tong C Y , Lin H M 
Published: July 2020

Abstract
Research on nanocrystalline materials, a new class of materials with a grain size of less than 20-30 nm in diameter, has flourished in the last decade because of their unique properties and Characteristics. While enormous amounts of nanocrystalline intermetallic alloys have been made by high energy mechanical alloying, little of this research has been carried out to study the formation of alloys of very low solid solubility elements such as Ag and Ni (0.1 at % at 750 °C).Upon quenching atoms in a state of high mobility, they can be “frozen” into unconventional random positions and thermodynamically metastable or unstable phases can be formed. This research was thus undertaken to synthesize nanocrystalline AgxNi1-x solid solution because fiber composites of this system have been widely used in low-voltage electrical circuits. This paper presents a TEM/AEM investigation of the traditionally immiscible nanocrystalline AgxNi1-xsolids formed by gas evaporation - vapor quenching method.