bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mesosome-like Structures in a Blue-green Alga, Phormidium Luridum
Authors: Edwards Mercedes R. 
Published: June 2020

The invagination of the plasma membrane (plasmalemma) to form vesicular or lamellar structures, usually called mesosomes (l) or plasmalemmosomes (2), has been extensively documented in bacteria (3) and more recently also in lower eucaryotes (e.g., the fungi, 4). Such structures have “been implicated in septum formation (i.e., cell division of gram-positive bacteria), in respiratory reactions, and in DNA replication.In photosynthetic bacteria, such as Rhodospirilium rubrum, vesicular structures derived from the plasma membrane were shown by Drews and Giesbrecht (5) to give rise to thylakoids (photosynthetic vesicles or chromatophores). Continuation between the plasma and thylakoidal membranes is readily seen in R. rubrum (6).
Type VI Glycogenosis
Authors: C. Garancis John , O. Hussa Robert , Lansdale Darrick 
Published: June 2020

Type VI glycogenosis is characterized by the phosphorylase deficiency in the liver and as a result of this inborn defect massive glycogen deposits occur in the liver. This report describes the findings of electron microscopic and biochemical analyses of liver and leukocytes from four children affected by Type VI glycogenosis.The most striking findings in the liver were large pools of cytoplasmic glycogen. These deposits consisted of monoparticulate glycogen with admixture of glycogen rosettes (Fig. 1). In the majority of hepatocytes, the cytoplasm was almost completely occupied by glycogen deposits, deeply embedded in which were few cytoplasmic organelles such as mitochondria, lysosomes and endoplasmic reticulum. Except for the presence of a few giant mitochondria with highly developed cristae and tubules, cytoplasmic organelles were normal in appearance.
Scanning Electron Microscopy of Adult Aedes Aegypti Mosquitoes
Authors: Colvard Jones Jack , M. Wehrung John 
Published: June 2020

Scanning electron microscopy studies were made on young adult male and female Aedes aegypti mosquitoes. Various surface details of the following anatomical parts were examined at various magnifications: compound eyes, antennae, anterior tentorial pits, various mouthparts, halteres, wings, legs, with special reference to the tarsal claws, and the genitalia.In all instances the mosquitoes were prepared for examination by sacrificing fresh material and spraying the sample with a commercial anti-static solution. This method resulted in droplet-shaped artifacts (particularly around the antennae). However, it was found that the mosquitoes could be examined in the scanning electron microscope for a period of up to 20 minutes without collapsing of the structure.
Ion Beam Etching Op Soft Biological Tissue Maintained At Low Temperatobes
Authors: Echlin P. , Wayte D. , Dronzek B. , Kynaston D. 
Published: June 2020

It has already been demonstrated (1) that it is possible to examine labile biological material kept at low temperatures using the temperature controlled stage module which has been developed for the Stereoscan scanning electron microscope. Following the success of these studies, attempts have been made to ion-beam etch soft biological tissue kept at liquid nitrogen temperatures inside the microscope column.Extremely hydrated plant material and delicate animal tissue were drained or damp dried, placed onto cooled aluminium stubs and rapidly quench frozen in Freon 22 (monochlorodifluoromethane) maintained at its melting point of -146°C by liquid nitrogen.
Advances in Freeze - Drying Employing Thermoelectric Cooling
Authors: Bendet Irwin , Rizk Nabil 
Published: June 2020

Two techniques have been developed in an attempt to eliminate the effect of surface tension forces during the drying of biological materials; namely, the critical point method of Anderson, and the freeze dry procedure of Williams. More recently, a procedure employing thermoelectric cooling was developed in this laboratory. This technique has now received further attention and development.Out present thermoelectric cooling unit* consists of four ceramic insulated modules connected in cascade, having 62, 31, 3, and 3 thermocouples, respectively (Fig. 1 ). The base stage is welded to a heat sink consisting of a copper block (2 1/2″ × 2″ × 1″), through which serpentines a 1/4″ wide channel, the thickness of the block, and which is connected by two threaded tubes to the base of the evaporating chamber (Fig. 2).
Electron Microscopy With Minimal Beam Damage
Authors: C. Williams Robley , W. Fisher Harold 
Published: June 2020

It has been previously shown that the electron beam as normally used in electron microscopy results in the destruction of molecules of untreated DNA1 and in the obliteration of the finer structures of tobacco mosaic virus embedded 9 in negative stain.We have developed methods whereby specimen damage by the electron beam is minimized by restricting irradiation of the region to be micrographed to that necessary for photographic exposure. Focusing and stigmatic correction are done on a selected specimen region nearby. In one method, applicable to a Siemens Elmiskop I, a minimal-size beam spot (∼2μ) is first placed near the edge of the viewing screen and visibje in the binocular.
A SYSTEM FOR PROTECTING AN OIL DIFFUSION PUMP AGAINST FAILURE OF THE MECHANICAL FORE PUMP, COOLING WATER, OR ELECTRICITY
Authors: Bigelow W. C. , Drogosz F. B. , Nitschke S. 
Published: June 2020

High vacuum systems with oil diffusion pumps usually have a pressure switch to protect against Insufficient cooling water; however, If left unattended for long periods of time, failure of the mechanical fore pump can occur with equally serious results. The device shown schematically in Fig. 1 has been found to give effective protection against both these failures, yet it is inexpensive and relatively simple to build and operate.With this system, pressure in the fore pump line is measured by thermocouple vacuum gage TVG (CVC G.TC-004) whose output is monitored by meter relay MRy (Weston 1092 Sensitrol) which is set to close if the pressure rises above about 0.2 torr. This energizes control relay CRy (Potter & Brumfield KA5Y 120VAC SPDT) cutting off power to solenoid-operated fore line valve Vf (Cenco 94280-4 Norm. Closed) which closes to prevent further leakage of air into the diffusion pump
A Simple Device for Multiple Angle Shadow Casting
Authors: Petrali J. P. , Donati E. J. , Mills K. R. 
Published: June 2020

A convenient device is described for shadow casting whole-mounted specimens at two angles simultaneously. The unit was used in our laboratory for studying vaccinia virus, conjugated antibody molecules, bacterial fimbriae and flagella, and microcapsules.The shadowing unit consists of an 8 x 8 x 6 centimeters stainless steel box with two adjustable shelves secured in juxtaposition onto a common piano-type hinge. Each shelf may be independently set to the desired shadowing angle up to 60 degrees. As many as twenty grids may be shadowed at one time.In addition to the real advantage of double-angled shadowing as a built-in check on emission angles, the unit may be rapidly aligned in any standard evaporator by use of a removable alignment platform which centers the box to the emitting source in the correct physical attitude for shadowing. Further, if desirable, an aperture may be placed in the same manner as the alignment platform for finer resolution.
Scanning Device Combined with Conventional Electron Microscope
Authors: Koike H. , Ueno K. , Watanabe M. 
Published: June 2020

Most of substances - organisms as well as crystals — consist of many micro-structures. It is important, in observation, separately to detect information on microareas of the specimen. In this respect, if the capabilities of the scanning electron microscope, such as the ability to detect information with regard to x-rays, secondary electrons, back scatterd electrons, transmitted electrons, and photons, are combined with those of conventional electron microscope, the resultant electron microscope may well be regarded as a new analytical instrument.With the JEM-100 type electron microscope combined with a scanning device, secondary electron images and transmitted scanning images were obtained. The incident electron probe used in the present scanning device was strongly demagnified by the prefield of the objective lens. In the objective plane the probe size of 30A was obtained.
High Resolution Color Recording for the Scanning Electron Microscope and the Electron Probe
Authors: Lublin P. , Fowler V. J. , Schlafer J. 
Published: June 2020

The advantages of color recording in the scanning electron microscope and the electron probe have been previously enumerated. The usual method of recording scanned images from these instruments is by photographing the display from a long-persistence black and white cathode ray tube. Previous attempts at color recording have included a variety of methods utilizing color filters, density traces, and color cathode ray tubes. These methods present difficulties in super-imposition of sequential images and/or poor resolution. Resolution of the cathode ray tube is particularly important in scanning electron microscopy.A new recorder providing high-resolution color micrographs for both the electron probe and the scanning electron microscope has been constructed. This instrument employs a multi-color laser which is scanned in synchronism with the electron beam in the column to give a point-to-point correlation.
Dynamic Observation of Magnetic Fields in the Scanning Electron Microscope
Authors: Kabaya A. , Russ J. C. 
Published: June 2020

The semiconductor industry has made substantial use of the SEM to examine components using voltage contrast.This is a variation in the secondary electron signal caused by the application of voltages to different parts of the sample.It results both from changes in the emission of secondary electrons, and modifications in their trajectories toward the positively charged collector that changes the number of electrons that strike the scintillator and are amplified to become the displayed signal.There have been a few efforts to observe magnetic contrast in the SEM, but in general the magnetic analog to voltage contrast has been unused.There has been some use of the SEM to study magnetic fields, however.It has been shown that the distortion in the scanning raster caused by an applied field can be used to map the field, but because this uses the action of the field on the high energy primary electrons rather than the secondary electrons, rather strong fields are required.This application is not related to magnetic contrast.
An Electron Microscope Study of Interdiffusion and Compound Formation in Ta-Au Thin Films
Authors: Tisone T. C. , Lau S. 
Published: June 2020

In a study of the properties of a Ta-Au metallization system for thin film technology application, the interdiffusion between Ta(bcc)-Au, βTa-Au and Ta2M-Au films was studied. Considered here is a discussion of the use of the transmission electron microscope(TEM) in the identification of phases formed and characterization of the film microstructures before and after annealing.The films were deposited by sputtering onto silicon wafers with 5000 Å of thermally grown oxide. The film thicknesses were 2000 Å of Ta and 2000 Å of Au. Samples for TEM observation were prepared by ultrasonically cutting 3mm disks from the wafers. The disks were first chemically etched from the silicon side using a HNO3 :HF(19:5) solution followed by ion milling to perforation of the Au side.
Surface Damage of Delustered Nylon 66 Fibers Exposed to Light
Authors: Zeronian S. H. , Tomioka M. K. , Pangborn J. 
Published: June 2020

Zeronian, using a scanning electron microscope-(SEM), found that when nylon 66 fabric was exposed simultaneously to light from a xenon arc lamp, and to air, and periodically sprayed with water, pits appeared on the surface of the semidull fibers. The size and number of the pits increased with time of exposure.In the present study, we examined the influence of TiO2 on the surface structure of 70-34-Z DuPont nylon 66 filament yarn exposed to light. Bright, semidull, and dull forms were used at respective TiO2 concentrations of 0.02, 0.30, and 2.0%. The yarns were exposed simultaneously to light and air in a Weather-Ometer, and were sprayed with water for 18 min every 2 hr.
The Future of Sputtering in the Electron Microscope Laboratory
Authors: Paulson G. G. , Ferrell R. E. 
Published: June 2020

In such fields as electronics and optics, the sputtering process is rapidly displacing the conventional evaporation process. Its major advantage is the ability to deposit a variety of refractory metals and dielectric materials with good control and reproducibility. This advantage and numerous others are valid reasons why sputtering may eventually displace thermal evaporation in the typical electron microscope laboratory. Sputtering is readily adapted to the procedures utilized in TEM, however, the following discussion highlights the advantages of sputtering for applying coatings to specimens for SEM.Sputtering is not a new concept. Numerous papers and books had been published before 1900 concerning the use of sputtering for depositing thin films.
A Photoemission Electron Microscope using an Electron Multiplier Array
Authors: Baxter William J. , Rouze Stanley R. 
Published: June 2020

We have converted a Philips thermionic emission electron microscope into a photoemission electron microscope by adding a simple ultraviolet illumination system, and a Channeltron Electron Multiplier Array (CEMA) for image intensification. This microscope provides photoemission images with or without heating of the sample, without removal of the surface oxide, and without activation. We illustrate with two examples: 1) a photoemission image of nickel, and 2) the first direct images of the exoelectron emission produced by abrasion of a metal surface.The microscope consists essentially of an electrostatic lens and two magnetic lenses. The immersion electrostatic lens is formed by the specimen, the Wehnelt cap at −15 kV, and the anode at ground potential.
Precipitation Hardening in Gold-Titanium Alloys
Authors: Graham M. 
Published: June 2020

The strength of gold alloys can be improved through heat treatment. Our previous work demonstrated an eight-fold increase in yield strength from the as-quenched to the maximum age-hardened state of a Au-4 at.% Ti alloy. This increase is attractive in terms of developing stronger gold alloys for clinical use and for studying strengthening mechanisms.Observations of yield stress as a function of aging treatment and test temperature, and on the nature of the yielding (serrated) allowed us to deduce a physical model of the strengthening mechanism. Concurrent transmission electron microscopy provided direct evidence about the structural changes accompanying heat treatment and about the modes of deformation. The results presented here illustrate the change in internal structure with precipitation and the resulting change in mechanical properties.
On the Origin of Recrystallization Texture
Authors: Rath B. B. , Hu H. 
Published: June 2020

The recrystallization process involves the nucleation and growth of strain-free grains and results in grain orientations which are grossly different from those in the deformed matrix. The texture developed during recrystallization has been attributed either to the oriented nucleation or to the oriented growth mechanisms. Although the orientation dependence of the growth rates of recrystallized grains is well recognized, the crystallographic relationships between the grain nuclei and the matrix are not clearly understood.The origin of recrystallization texture has been investigated in detail by examining the orientations and the size of the stable nuclei and their relation to those of the surrounding matrix.
Lung Ultrastructure of Exercising Monkeys After Nitrogen Dioxide Exposure
Authors: Bils Robert F. 
Published: June 2020

Mice, rats, guinea pigs, rabbits and other common laboratory animals have been used in toxicology for many years. However, extrapolation of results to humans will always be under question. Although subhuman orimates have been utilized in many areas of research, little work has been done on the effects of toxic gases on the respiratory system of monkeys. Henry et al. bserved an emphysematous condition in monkey lungs exposed to 50 ppm NO2 for 2 hrs. while studying resistance to infection.This is the beginning of a comprehensive project exposing exercising monkeys to atmospheric pollutants, and analyzing the morphological, biochemical and physiological changes that occur.
A New Method For Staining Epon-Araldite “Thick” Sections
Authors: Lloyd B. J. , Davis D. A. 
Published: June 2020

In electron microscopy, the preparation and examination of "thick" sections is frequently of considerable value preliminary to final sectioning and staining. The use of the following simple method has been found to increase a number of histological details without the need to employ time-consuming supplemental stains.A variety of tissues were prefixed for 1.5 hours in 0.05 M phosphate buffered acrcplein (0.6%) and purified glutaraldehyde (2.8%) at pH 7.5. Subsequently, postfixation was carried out in 0.05 M phosphate buffered osmium tetroxide for one hour at pH 7.5.
Quantitative Measurements on the Ion Etching of TMV
Authors: Bendet Irwin , Rizk Nabil 
Published: June 2020

Preliminary results reported last year on the ion etching of tobacco mosaic virus indicated that the diameter of the virus decreased more rapidly at 10KV than at 5KV, perhaps reaching a constant value before disappearing completely.In order to follow the effects of ion etching on TMV more quantitatively we have designed and built a second apparatus (Fig. 1), which incorporates monitoring devices for measuring ion current and vacuum as well as accelerating voltage. In addition, the beam diameter has been increased to approximately 1 cm., so that ten electron microscope grids can be exposed to the beam simultaneously.
The Ultrastructure of Mature and Mineralizing Cartilaginous Matrix in Deer Antler (Odocoileus Hemionus Hemionus)
Authors: Newbrey Jarrett W. , Banks William J. 
Published: June 2020

Core biopsies of mature and mineralized cartilage were removed from the main beams and tines of deer antler at various times throughout the growing season and were examined with an electron microscope (Hitachi, HS-8; Zeiss, EM-9A). Certain morphological characteristics were identical with those features reported for matrices of mature and mineralizing somatic cartilage .The lacunae (L) of the mature cartilage cells were not devoid of matrix components. Although the lacunae lacked any banded collagen fibers (Fig. 1), they did contain many interconnected fibrils (F) which were associated with lead-stained granules (arrows). The lead binding coincided with matrix granules described in the lacunae and general matrix of growth plate cartilage.
Functional Acinar Cell Carcinoma of the Pancreas
Authors: Burns W. A. , Vander Weide G. C. , Matthews M. J. 
Published: June 2020

Malignant tumors arising from pancreatic acinar cells are relatively uncommon. Rarely these tumors may be functional, secrete amylase or lipase and present clinically with polyarthropathies and skin lesions resembling erythema nodosum. Some of the reported cases were supported with confirmative data, but none to our knowledge had chemical and ultrastructural confirmation. We wish to report the electron microscopic and bio-chemical studies of a functional acinar cell carcinoma of the pancreas.The patient was a 52 year old, black male who had constant complaints of polyarthropathy and was found to have a tumor of the pancreas with liver metastases.Tissue from a pre-mortem liver biopsy and post-mortem from the pancreatic tumor and the liver metastases were examined.
The Disappearance of the Acid Mucopolysaccharide Coating in Blood Vessels Exposed to Oxygen, Radiation and in Old Age and Possible Implications
Authors: Philpott Delbert E. , Takahashi Akira , Turnbill Charles 
Published: June 2020

The blood vessels are known to be involved in radiation pathology, both the fragility and permeability being altered. Delayed radiation response has been shown to involve a loss of the blood supply to necrotic areas. Since the structure of the mucopolysaccharide (MPS) coating on the luminal wall is heparin-like in nature and heparin has known anti-coagulant properties, the observed increase in clotting in older persons suggests possible alteration of the acid MPS coating.Rats were treated in several ways to examine the effect of various factors on the MPS coating. Young rats were whole-body irradiated with 2400r X-rays and sacrificed 24 and 48 hours later. Another group of rats were exposed to 100% oxygen at one atmosphere for periods up to 72 hours.
Scanning Electron Microscopy of Plant Surfaces - Applications
Authors: Dayanandan P. , Kaufman P. B. 
Published: June 2020

Previous studies and our own observations of surface features in more than 80 species show that the SEM can be of great value in determining the nature and distribution of stomata, trichomes, wax, cuticular ridges, silica bodies, spores and other particulate pollutants as well as meristems and their derivatives. We suggest applications of surface studies to the fields of taxonomy and plant water relations.Many epidermal surfaces can be observed with or without coating at 15 KeV with no detectable alterations in the wax pattern. Wax is deposited as granular, rod-like, thread-like or plate-like structures. Of particular interest are the wax patterns around stomatal apparatuses.
Fine Structure of Posthodiplostomum Minimum Metacercarial Cyst Wall
Authors: Mitchell C. W. 
Published: June 2020

The metacercaria of the digenetic trematode Posthodiplostomum minimum inhabit the major visceral organs, e.g. liver, kidney or heart, of numerous species of fresh-water fish as second intermediate hosts. These larval trematodes establish a thin cyst wall which is composed of a cellular, outer wall of host origin and an inner, acellular layer of parasitic origin. This report describes some preliminary observations on the ultrastructural organization of the metacercarial cyst wall found within naturally infected sunfish liver.These observations represent the first strigeid cyst studied by electron microscopy. However, cyst structure resembled others encysted within tissues of an intermediate host. A primary wall, apparently secreted by the parasite, prevents host destruction of the metacercaria.
Action of the Glandular Vas Deferens in the Nematode Ascaris Lumbricoides
Authors: Foor W. Eugene 
Published: June 2020

It has been well demonstrated that the spermatozoa of certain nematodes undergo marked morphological and physiological changes after they have been deposited in the reproductive tract of the female worm. Although it was previously assumed that the spermatozoan changes occur in response to stimulatory substances present within the female tract, recent investigations utilizing Ascaris lumbricoides as the experimental model, provide strong evidence that the substances responsible for the spermatozoan changes actually originate in the glandular vas deferens of the male worm.In Ascaris the glandular vas deferens is a whitish gland located posterior to the seminal vesicle. The cells comprising the gland are characterized by the presence of large amounts of rough endoplasmic reticulum and Golgi saccules which apparently give rise to substances which are secreted into adjacent collecting ducts (figure 3) and eventually find their way to the lumen.