bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation And elemental analysis of ancient fibers
Authors: Angel Allen , Jakes Kathryn A. 
Published: June 2020

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.
Microanalysis and electron energy loss spectroscopy of polymers
Authors: Briber R. M. 
Published: June 2020

Analytical electron microscopy has progressed in recent years such that quantitative chemical information can be obtained from very small volumes of sample. In principle, the composition of regions on the order of a few namometers in both diameter and thickness can be determined using energy dispersive x-ray analysis (EDS) and electron energy loss spectroscopy (EELS) [1,2], In the case of organic polymers the limitations to quantitative microanalysis are generally due to the sample and not to the instrument. Radiation damage induced mass loss often proves to be the constraining factor in obtaining quantitative information from small volumes of sample [3], The principles and processes of radiation damage in organic materials and polymers can be found in various review articles [4,5].The principles underlying both analytical x-ray spectroscopy and electron energy loss spectroscopy are closely related. When an electron in the incident beam loses energy (i.e. inelastically scattered) by "knocking" out an inner shell electron from an atom present in the sample there are two aspects that are of value for compositional analysis.
Domains in single crystals of poly-4-methyl-pentene-1
Authors: Pradère P. , Revol J.-F. , John Manley R. St. 
Published: June 2020

Polymer single crystals are generally considered to be structurally homogeneous. In this paper it is shown that in a given single crystal of poly-4-methyl-pentene-1 (P4MP1) there exist narrowly delimited domains that give rise to different electron diffraction (ED) patterns. The shape and location of these domains is characterized by diffraction contrast imaging in the dark field (DF) mode.Monolayer single crystals of P4MP1 polymorphs I and III were prepared in dilute solution (concentration ranging from 0.01 to 0.05%). Form I was obtained by slow cooling of a hexadecane solution whereas form III was prepared by isothermal crystallisation in xylene at 60°C. Crystals were deposited on carbon coated grids and observed with a Philips EM 400 T electron microscope operated at 120 kV. The crystals are very radiation sensitive and the total end point dose, measured by the fading of the ED pattern is 27 C m-2.
Structural transitions and organization of micelles in block copolymer/hompolymer blends
Authors: Thomas Edwin L. , Kinning David J. 
Published: June 2020

Spherical and cylindrical micelles are quite common in lipid/water systems. The self assembly of amphiphilic molecules into well defined geometries has been extensively studied and is explained in terms of geometric and packing properties in addition to electrostatic, van der Waals and solvation forces. While macromolecular self assembly may seem more complex than for such small molecule systems, it is actually a simpler physical situation to model. Much can be learned from the combined study of each type of system.In block copolymer/homopolymer blends the scale of the phase separation is restricted to the radius of gyration of the polymer blocks (typically several hundred A). By varying the composition and the molecular weights of the blocks and of the homopolymer, a wide range of morphologies and therefore physical properties can be achieved.
Combination of cryo-SEM and WET-SEM
Authors: Makita Takashi , Hirabara Kazumi , Hirose Haruko 
Published: June 2020

WET-SEM is a version of commercially available SEM equipped with Robinson's type of wide-angle backscattered electron detector to observe wet samples under low vacuum(0.3-0.5 torr) and it has been used to variable biological samples with or without chemical fixation. Its versatility to observe hydrated specimens without any metalic coating is obviously advantageous to application of cryo-SEM to biological samples.Recent improvement of nitrogen gas cooled cold stage, and vacuum transfer device(Hexland, England) made the WET-SEM(ISI, Akashi, Japan) as a tool for quick survey of unfixed, hydrated, uncoated, and frozen fractured tissue blocks of animals. For examples, tissue from the rat liver or the mice kidney was quickly frozen in nitrogen slush for several minutes and then transfered to prechamber with a type of vacuum transfer system. Within the prechamber the surface of frozen sample is sublimated or fractured under vacuum and then the sample is ready to be seen on the cryo stage which is cooled by nitrogen gas.
Alterations of ultrastructure and elemental composition in cultured human epidermal keratinocytes after treatment with nitrofurazone and silver sulfadiazine
Authors: Crooker A. R. , Myers M. C. , Beard T. L. , Graham E. S. 
Published: June 2020

Cell culture systems have become increasingly popular as a means of screening toxic agents and studying toxic mechanisms of drugs and other chemicals at the cellular and subcellular levels. These in vitro tests can be conducted rapidly in a broad range of relevant mammalian culture systems; a variety of biological and biochemical cytotoxicity endpoints can be examined. The following study utilized human keratinocytes to evaluate the relative cytotoxicities of nitrofurazone (NF) and silver sulfadiazine (SS), the active ingredients of FURACIN(R) Topical Cream and SILVADENE(R) Cream, respectively. These compounds are anti-infectives used in the treatment of burn patients. Cell ultrastructure and elemental composition were utilized as cytotoxicity endpoints.Normal Human Epidermal Keratinocytes (HK) were prepared from the EpiPackTM culture system (Clonetics Corporation, Boulder, CO). For scanning electron microscopy (SEM) and transmission electron microscopy (TEM), cells were seeded on sterile 35 mm Falcon plastic dishes; for elemental microanalysis, cells were plated on polished pyrolytic carbon discs (E. Fullam, Latham, NY) placed in the culture dishes.
Estimation of the noise in TEM image recorded on “imaging plate”
Authors: Oikawa T. , Mori N. , Katoh T. , Harada Y. , Miyahara J. , Matsuo T. 
Published: June 2020

The “Imaging Plate”(IP) is a highly sensitive image recording plate for X-ray radiography. It has been ascertained that the IP has superior properties and high practicability as an image recording material in a TEM. The sensitivity, one of the properties, is about 3 orders higher than that of conventional photo film. The IP is expected to be applied to low dose techniques. In this paper, an estimation of the quantum noise on the TEM image which appears in case of low electron dose on the IP is reported.In this experiment, the JEM-2000FX TEM and an IP having the same size as photo film were used.Figure 1 shows the schematic diagram of the total system including the TEM used in this experiment. In the reader, He-Ne laser light is scanned across the IP, then blue light is emitted from the IP.
A new antibody label 5-10 times smaller than previous ones
Authors: Hainfeld James F. 
Published: June 2020

By covalently coupling an undecagold complex to an Fab’ fragment, the smallest gold-conjugated antibody label yet devised has been synthesized. Its overall dimension is 50 x 30 x 20 Å and when bound to an antigen, the gold cluster is 40-50 Å from the antigen surface. The preparation procedure does not alter the activity and specificity of the antibody since coupling of the gold cluster is at a crystallographically known position at the opposite end of the Fab’ fragment from the antigen combining site.One significance of this new label is that with a smaller E.M. antibody label, higher resolution of labeling is possible. In fact, if monoclonals are used, specific sites on a single macromolecule, or subunits of a protein complex could be mapped.
Nuclear lamina and regulation of nuclear envelofe structure
Authors: Gerace Larry , Aebi Ueli , Burke Brian , Suprynowicz Frank 
Published: June 2020

The nuclear lamina is a protein meshwork that lines the nucleoplasmic surface of the nuclear envelope. In numerous higher eukaryotic cells, the lamina is known to contain a polymer of 1-3 major polypeptides (“lamins“) that form an insoluble supramolecular assembly during interphase. The lamina is thought to provide both a skeletal framework for the nuclear envelope (that regulates its disassembly and reformation during mitosis) and an anchoring site at the nuclear periphery for interphase chromosomes. Recent structural and functional studies on the nuclear lamina have yielded important new insight on its roles in nuclear architecture.Using electron microscopy, we found that the nuclear lamina of Xenopus oocytes is a meshwork of intermediate-sized (8-12 nm) filaments arranged in a near-tetragonal lattice having a spacing of 52 nm.
Fine structure of the cupula
Authors: Cohen G. M. , Domeier M. L. 
Published: June 2020

The cupula functions as a sensitive biological transducer that undergoes extremely limited mechanical displacements in its normal dynamic range. Cupular displacements are coupled to the bending and stimulation of hair cell cilia. However, details of cupular-ciliary coupling and of cupular attachments to the ampullary crest are unsettled because of difficulties in preserving the cupula without severe distortion from fixation and dehydration. With conventional fixation procedures, the cupula either pulls away from crest or collapses to a fraction of its original volume. Our objective was to reduce cupular shrinkage.We used the inner ears of 1 day-old chicks (White Leghorn) and 3 month-old mice (C57BL/6). The inner ears were fixed 3-72 h in 1.5-1.75% glutaraldehyde in 150 mM KC1 buffered with potassium phosphate, pH 7.3. To the basic solution, we sometimes added spermine (0.1%) or lysine (0.25%).
Correlations of acid phosphatase activity and β-VLDL/colloidal gold conjugate localization in monocyte derived macrophages in culture: Intermediate voltage electron microscopy observations
Authors: Henson Dru A. , Lewis Jon C. 
Published: June 2020

Lipid uptake by arterial cells is hallmark to atherosclerosis. Since in the progression from nascent to more advanced lesions lipid accumulation correlates with cell death and tissue necrosis, the relationship of lipid uptake to lysosomes is of interest. Recently, we reported the use of macrophage cultures to study lipoprotein uptake and to ultrastructurally correlate uptake with lipid accumulation and lysosomal activity. Although we have documented lipoprotein/gold tracer in lysosome-1ike organelles, simultaneous observation of both acid phosphatase reaction product and the β-VLDL gold tracer was limited by similarity of product and tracer electron densities. Reported is the use of IVEM to circumvent specimen contrast and simulaneously identify β-VLDL-gold within acid phosphatase positive lysosomes.Pigeon monocytes, isolated from citrated whole blood were cultured in MEM-HEPES supplemented with 10% chicken serum, vitamins, L-glutamine, and antibiotics. Following 7 days in culture the monocyte/macrophages were incubated with pigeon β-VLDL conjugated to colloidal gold.
Biological specimen preparation for SEM by a method other than critical point drying
Authors: Adams J. L. , Battjes C. J. , Buthala D. A. 
Published: June 2020

Quality sample preparation for SEM is important to observe fine details without artifacts, and good preparation requires proper fixation, dehydration, drying and coating, An alternative 5 min passage in hexamethyldisilazane (HMDS) can replace critical point crying (CPD) and gives satisfactory results on many biological samples. CPD procedure may take up to 1 h per sample to ensure adequate drying, therefore a brief rinse in HMDS followed by air drying requires less time and equipment yet provides excellent results.Various biological samples were fixed in 3% glutaraldehyde; rinsed 3 times in Millonig's phosphate buffer for 10 min each; post-fixed in 1% osmium tetroxide for 1 h; rinsed as before; fixed again in 1% tannic acid (TA) for 30 min-1 h; rinsed well and partially dehydrated to 70% ethanol; placed in 1% uranyl-acetate (UA) in the dark, overnight: rinsed with 70% ethanol until UA cleared and then dehydrated through 100% ethanol.
Performance and applications of a field-emission gun TEM/STEM
Authors: Brock Judith M. , Otten Max T. , de Jong Marc. J.C. 
Published: June 2020

A Field Emission Gun (FEG) on a TEM/STEM instrument provides a major improvement in performance relative to one equipped with a LaB6 emitter. The improvement is particularly notable for small-probe techniques: EDX and EELS microanalysis, convergent beam diffraction and scanning. The high brightness of the FEG (108 to 109 A/cm2srad), compared with that of LaB6 (∼106), makes it possible to achieve high probe currents (∼1 nA) in probes of about 1 nm, whilst the currents for similar probes with LaB6 are about 100 to 500x lower. Accordingly the small, high-intensity FEG probes make it possible, e.g., to analyse precipitates and monolayer amounts of segregation on grain boundaries in metals or ceramics (Fig. 1); obtain high-quality convergent beam patterns from heavily dislocated materials; reliably detect 1 nm immuno-gold labels in biological specimens; and perform EDX mapping at nm-scale resolution even in difficult specimens like biological tissue.The high brightness and small energy spread of the FEG also bring an advantage in high-resolution imaging by significantly improving both spatial and temporal coherence.
A high-resolution, wide-field, optically coupled, digital CCD camera for the JEOL 4000-EX intermediate-voltage electron microscope
Authors: Horn Edward , Metzger Gregory J. , Ashton Francis T. , Peachey Lee D. 
Published: June 2020

We have designed and constructed a camera system for acquisition of digital images directly from a JEOL 4000-EX 400 kV transmission electron microscope. Our major goal was the ablity to sample and test images for suitability for various forms of image processing and analysis during a session on the microscope, rather than after processing and digitizing films, so that adjustments could be made while the specimens were still in place. Our design parameters were 1) good resolution, in terms of pixels in the image, 2) wide field, so low magnification images could be obtained, 3) no interference with normal operation of the microscope, including the film camera, and 4) minimal modification of the microscope.Cameras positioned below the film camera have narrow fields of view because of increase in image size below the film camera and the small size of CCD targets relative to film. We chose a position above the microscope's fluorescent viewing screen, where there is a convenient port on the 4000-EX, and achieved a field width approximately equal to that on film.
Determination of mean inner potential and thickness in wedge shaped specimens by interferometry and electron holography
Authors: Herring R.A. , Tanji T. , Tonomura A. 
Published: June 2020

Knowlege of a specimens' mean innner potential and thickness is important for many purposes including holography, analytical (AEM) and microstructural analysis. This paper shows that both electron interferometry and holography can easily be used to determine the mean inner potential, as well as, the thickness at every point within a TEM specimen. The relative fringe shift, Δs/s , in a hologram by an object is linearly proportional to the object's mean inner potential, V, and thickness, d, and is given by,where C is considered a constant and described by the relativistic energy correction divided by the acceleration energy, E, and wavelength, λ, i.e. [(1 + eE/mc2)/(l + eE/2mc2)/2Eλ]. Inorder to separate d and V another holographic image is required to provide another image equation. This image equation is easily provided by rotating the specimen a known angle, Δθ, such that d becomes a function of Δθ.
The morphology of moth and butterfly wing scales which exhibit reflective diffraction phenomena
Authors: Lee M.E. , de Neijs E.O. 
Published: June 2020

The butterfly and moth families illustrate how nature has used diffractive micro-relief structures to achieve unique optical effects. Whereas the majority of insects use pigments (absorption) or occasionally thin film multi-layer structures (interference) to create colour, the wings of many families of butterfly and moth have complex 2-D or 3-D arrangements of submicron grating structures which produce zero and higher order diffraction conditions.The special properties of a diffraction grating can be understood by light incident perpendicularly on a transmission grating. The light is diffracted into a number of grating orders at angles θn given by the grating equation sin θn = n λ/d where λ is the wavelength of the light, n = 0, ± 1, --- and d is the grating period. The same conditions are valid for reflective diffraction structures. If the grating period is finer than the wavelength ie. d < λ, no first order diffraction exists for normal illumination.
Molecular organization in phospholipid monolayer domains by electron diffraction
Authors: Hui S. W. , Yu H. 
Published: June 2020

In the LC/LE phase of phospholipid monolayers at the air/water interface, solid and fluid domains may be visualized by epi-fluorescence microscopy. Supposedly, solid domains are distinguished by the absence of fluorescence due to the preferential partitioning of most fluorescent dyes to the surrounding fluid phase lipids. The size, shape and stability of these domains are governed by molecular dipole-dipole interaction and inter-phase line tension. While x-ray and neutron diffractions offer some global average molecular packing information on a large sampling area of monolayers, selected area electron diffraction may provide local structural information within and along individual domains.Dipalmitoyl-monomethyl-phosphatidylethanolamine [DP(Me)PE] and dipalmitoyldimethyl-phosphatidylethanolamine [DP(Me)PE] monolayers were spread on an environmentally controlled Langmuir trough. The monolayers were adjusted to the LE/LC phase by a servo-motor-driven Teflon bar moving along the surface of the trough.
Fractal analysis with scanning probe microscopy
Authors: West Paul E. , Marchesse-Rugona Sid , Li Zhuoning 
Published: June 2020

Surface roughness determined qualitatively by direct visualization can be correlated to several physical properties. However, finding a suitable method of quantifying surface roughness, until recently, has been difficult. The concept of Fractal Dimension, recently popularized by Mandelbrot(1982) has been extremely successful in quantifying surface roughness and relating it to such measurable physical properties such as; cleanability, catalytic activity, rate of corrosion, and even flavor.Atomic Force Microscopes permit direct three dimensional measurements of surface microstructure. AFM images are obtained by measuring the motion of a sharp stylus as it is scanned across a surface. Because the AFM directly measures three dimensional topograms, it is ideally suited for two dimensional and three dimensional fractal analysis. Other microscope techniques such as the scanning electron or optical microscope give only two dimensional magnification and fractal measurements are not easily made.The Atomic Force Microscope enables us to obtain the fractal dimension of surface profiles as well as surface areas. For surface profiles we use a box counting method (Mandelbrot 1986, Chesters et al. 1989).
An application protocol of 3-D variance estimation theory for significance assessment of reconstructions and detection of 3-D conformational changes
Authors: Liu Weiping , Frank Joachim , Boisset Nicholas 
Published: June 2020

A theory has been developed for estimating the 3-D variance of the weighted back-projection reconstruction from a single-exposure random conical tilt series. The variance estimate provides a new dimension of information that would otherwise be buried due to the averaging nature of the 3-D reconstruction. By combining the analysis of 3-D variance with classification and 3-D reconstruction, the average 3-D structure as well as the significance and the variability of its local features can now be studied. Through its successful applications to the 50S ribosomal subunit depleted of L7/L12 proteins and the hemocyanin-Fab complex, an application protocol of 3-D variance is proposed as outlined in the following:(I) If we have one homogeneous projection set:*compute the 3-D reconstruction*compute the 3-D variances corresponding to different low-pass filter cut-off frequencies.From this we can obtain
Scanning electron microscopy and x-ray analysis of fossilized materials from calvert cliffs, md
Authors: Milburn Darolyn , Moses Melonie , Hammond Ernest 
Published: June 2020

Diatoms are classified in the plant kingdom as Bacillariophyta. They are unicellular plants with cell walls of silica and are found in all types of fresh and salt waters. Some species have been found in different types of soils, as well. The oldest diatoms were marine and were from the Cretacious period. “No fresh water diatoms are known prior to the Miocene era.”Several students went to the Calvert Cliffs located on the Western Shore of the Chesapeake Bay, near the confluent of the Patuxent River in southern Maryland. Fossils were collected and the scrapings were examined under the scanning electron microscope. Also, an x ray analysis was made and the objects were photographed for digital imaging processing. The x ray analysis revealed that the fossils contained large quantities of silicon, calcium, magnesium, iron and oddly enough, plutonium.From the photographs and x ray analysis, the identification of the diatoms is narrowed down and eventually identified.