bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum expression of microRNA-16 in a cohort of Egyptian patients with ulcerative colitis and its correlation with disease extent and severity
Authors: Saad Hussein Mahmoud , Ali Ezzat , Baddour Nahed , Ibrahim Mohamed Eid , Tayae Eman 
Published: June 2020

AbstractUlcerative colitis is one of the IBDs. Its etiology and pathogenesis remain undefined with an interaction between environmental, genetic and immunological factors is the most accepted explanation. Several recent studies have examined microRNA expression in the peripheral blood and tissues from IBD patients. The study aims at assessing the expression of serum miR-16 in ulcerative colitis patients and its correlation with disease extent, activity and severity. It included 30 treatment naїve ulcerative colitis patients of different presentations. Serum miR-16 expression was assessed using reverse transcriptase quantitative real time PCR (RT-qPCR), and then correlated with that of a group of 20 healthy subjects to assess its role in diagnosis of ulcerative colitis. Also, it was correlated with disease extent (proctitis, left sided colitis, extensive colitis) and disease activity and severity indices (Truelove and Witts criteria, fecal calprotectin and UCEIS). Thirty ulcerative colitis patients were enrolled, 53% had mild, 37% had moderate, while 10% had severe disease. Concerning endoscopic extent, 8 had proctitis, 14 had left sided colitis and 8 had extensive colitis. Serum expression of miR-16 in the 30 patients were compared to that of the healthy control subjects. The patients’ group showed median serum miR-16 expression of 1.91, 1.13 for the control group with a significant difference between both groups. Correlation between serum miR-16 expression with disease extent, activity and severity showed no significant relation. From the current study we can conclude that increased serum expression of miR-16 is associated with ulcerative colitis despite no significant relation to disease activity extent or severity.
Electron Microscopy of Carcinomas of the Lung
Authors: Mackay B. , Mandavia M. , Lukeman J. M. , Mountain C. F. 
Published: June 2020

Carcinoma of the lung is the most common malignant neoplasm in males and the incidence continues to rise. The inadequacy of current methods of treatment is reflected in the poor prognosis: only 5% of patients survive for more than five years following diagnosis.In order to assess the effectiveness of new therapeutic modalities, accurate pathologic diagnosis is essential, and it is recognized that a proportion of these tumors can not be accurately classified by light microscopy alone. We have now studied over one hundred lung carcinomas with correlated light and electron microscopy, and our findings indicate that electron microscopy can be an invaluable aid in the diagnosis and classification of the tumors. Study of the fine structure of the tumor cells can provide the basis for a more precise classification than is currently used in clinical studies, and additionally give insight into problems of histogenesis.
Ultrastructure of Some Planktonic Formainifera
Authors: Zucker William H. 
Published: June 2020

Planktonic foraminifera are widely-distributed and abundant zooplankters. They are significant as water mass indicators and provide evidence of paleotemperatures and events which occurred during Pleistocene glaciation. In spite of their ecological and paleological significance, little is known of their cell biology. There are few cytological studies of these organisms at the light microscope level and some recent reports of their ultrastructure.Specimens of Globigerinoides ruber, Globigerina bulloides, Globigerinoides conglobatus and Globigerinita glutinata were collected in Bermuda waters and fixed in a cold cacodylate-buffered 6% glutaraldehyde solution for two hours. They were then rinsed, post-fixed in Palade's fluid, rinsed again and stained with uranyl acetate. This was followed by graded ethanol dehydration, during which they were identified and picked clean of debris. The specimens were finally embedded in Epon 812 by placing each organism in a separate BEEM capsule. After sectioning with a diamond knife, stained sections were viewed in a Philips 200 electron microscope.
Correlation Between Inelastic Electron Scattering and Secondary Electron Production
Authors: Voreades D. , Crewe A. V. 
Published: June 2020

The mechanism of secondary electron production is currently under investigation in our laboratory. The present work is concerned with the correlation between an energy loss event and the production of a secondary.The idea behind the experiment is that the energy needed for the production of a secondary electron by electron bombardment can only be provided by the impinging one. On the other hand, it is well known that these electrons experience characteristic energy losses when they pass through a specimen. Characteristic energy losses of various substances are of great interest since they provide important information about the specimens. Consequently we want to find out how one can correlate a characteristic energy loss with the production of'a secondary electron.
Multiple Cavity Disk Preparation for Transmission Electron Microscopy Combining Spark Machining and Electropolishing
Authors: Shaw G. Gordon 
Published: June 2020

The usefulness of the disk technique for T.E.M. is extended by increasing the number of cavities in each disk. This result can be achieved, without sacrificing transmission area in each cavity, by the following means: A simple tool, as shown in Fig. 1, is made by drilling four 40-mil holes in a piece of 160-mil drill rod, and soldering in four 40-mil pieces of drill rod.The disks are prepared from bulk material, 20 to 40 mils thick, by spark machining with a tubular brass tool to yield a disk approximately 160 mils in diameter. A disk is cemented to a brass block with a very thin layer of Duco cement. The block with mounted disk is placed on the platform of a spark machine and the tool shown in Fig. 1 is allowed to penetrate by spark erosion (using the fine cut) until 15 mils of metal remains between the face of the tool and the side of the disk mounted on the block. Fifteen mils is allowed for electropolishing to insure the removal of damage produced by spark erosion.
Cell Death in the Normal Epiphyseal Cartilage of the Rat
Authors: Fahmy Aly 
Published: June 2020

The ultrastructure of the upper tibial epiphyseal cartilage plate of weanling and plateaued Sprague-Dawley rats growing under normal conditions has been studied, in order to establish a base-line for the future investigation of the site and mechanism of action of certain hormones which are known to affect the growth and maturation of long bones.Observations have been made concerning the character and amount of the secretory products in the cells of the various zones, as well as the characteristics of the constituents of the intercellular matrix. Our findings have confirmed and amplified published observations on the ultrastructure of cartilaginous tissues in a variety of species in general.
The Changing Phenomenon of Fibrillar Complex in Streptomyces Cinnamonensis
Authors: Chen Pearl Liu 
Published: June 2020

It is generally recognized that (1) the nuclear region of the procaryotic organisms consists of randomly arranged fibrils, (2) the nuclear fibrils of bacteria may represent DNA or some material closely related to it, and (3) it is generally believed that the nuclear division of the procaryotic organisms is that of amitosis. The result of my recent investigation reveals that the fibrillar complex in the nuclear region exhibits a variety of configurations and change of position similar to the stages characteristic of chromosome movement in higher organisms.The nuclear region of S. cinnamonensis consists of two distinct phases: a dense fibrillar complex and a less dense matrix in which the dense fibrillar complex is embedded. The dense fibrillar complex occurs in two main states, dispersed and compact. When in a dispersed condition the fibrillar phase exhibits a loose network (Fig. I), and when in a compact condition it appears as organized fibrils which in turn display a variety of configurations.
An Image Intensifier System for the Electron Microscope
Authors: Anderson K. 
Published: June 2020

The possibilities of intensifying the light image produced on the fluorescent screen of the microscope have been known for some time. The first practical system was described by Kushnir etal (1958) who used a five stage cascade type image intensifier. More recently a system has been described by Sadashige 1958. This technique has been used to develope a system for the EM6G/EM6B electron microscope.The system employed can be seen from the schematic diagram in Fig. 1. The intensifier tube is a 4 stage cascade “sandwich” type image intensifier. The output can either be viewed directly or by using the T. V. camera as shown in the diagram.
Ion Beam Etching of Biological Material in the Scanning Electron Microscope
Authors: Echlin Patrick , Kynaston David , Knights Paul M. 
Published: June 2020

An ion source has been designed to operate in the chamber of the Stereoscan scanning electron microscope and provides facilities for etching specimens in situ. The source is a demountable cold cathode discharge type requiring only simple control.The ion beam described above has been used to progressively etch away hard or resilient biological material. This is the first time that ion beam etching of botanical specimens has been followed inside the scanning microscope, and marks the beginning of a range of dynamic experiments using this form of instrumentation.
Scanning Electron Microscopy of the Outer Taste Pore from a Human Tongue
Authors: Kaufman Arenberg I. , Marovitz W. F. , Mackenzle A. P. 
Published: June 2020

Increasing use is now being made of the scanning electron microscope for soft biologic tissues. The use of chemical fixation followed by freeze-drying, facilitates surface observations of tissues which otherwise would not be possible.Four hours following necropsy a sample of human tongue was removed. This specimen was fixed in 10% neutral formalin, postfixed in 1% osmic acid, dehydrated in graded series of alcohol, and evaporated, in vacuo, over a Linde molecular sieve at -30 ± 1°C. The specimen was plated with gold: palladium (40: 60) in a vacuum evaporator to an approximate 200 Å thickness. The emissive mode of the Cambridge Stereoscan Mark II scanning electron microscope was used for this study.
High Resolution Scanning Microscopy
Authors: Crewe A. V. , Wall J. 
Published: June 2020

We have previously reported on the development of a scanning microscope with a resolution of 20 Å. This instrument has now been improved so that the current point resolution is about 5 Å at 18 Kv.The microscope consists of a field emission gun followed by a single objective lens (see Fig. 1). The gun produces an image (real or virtual) of the field emission source which is then demagnified by the lens. The focal length of this lens has been shortened from 1 mm to 0.6 mm to produce a second beam crossover at the exit of the lens.
Structure and Function of Pancreatic Beta Cells in Streptozotocin Diabetes
Authors: Liss R. H. , Cotton F. A. , Palm P. E. , Kensler C. J. 
Published: June 2020

Streptozotocin, an antibiotic with anti-tumor activity, is diabetogenic in rats and hamsters. The present communication is a report on the extent and duration of structural and chemical changes associated with streptozotocin diabetes in rats and hamsters.Sprague-Dawley male rats and male hamsters (~255 grams) received a single intravenous dose of streptozotocin (100 mg/kg) in citrate buffer. Pre-test and experimental determinations of glycosuria and blood sugar were made. Islet cells from rats and hamsters were prepared for electron microscopy at selected intervals, between 5 minutes and 144 days, after dosage.
Electron Microscopy of the FBJ Osteosarcoma Virus
Authors: Biskis B. O. , Finkel M. P. 
Published: June 2020

Finkel, Biskis, and Jinkins reported extraction of a virus (FBJ) from a spontaneous mouse osteosarcoma, in 1966. Although FBJ virus contains the group-specine complement fixing antigen common to viruses of the leukemia-sarcoma complex, in 28 cell-free passages to date in mice it has produced only bone tumors.In sections of the tumors virus particles appear in extracellular spaces and budding from cell membranes (Fig. 1). Morphologically, FBJ is a Type C virus, as designated by W. Bernhard, and it would be called Muri virus, Sarcomatis according to recommendations of the Provisional Committee for Nomenclature of viruses.
The Role of Transmission Electron Microscopy in Characterizing the Nature and Behavior of Grain Boundaries
Authors: Murr L. E. 
Published: June 2020

Grain boundaries represent the single, most dominant imperfection in structural materials of engineering and industrial importance, and are a controlling factor in the strength of materials. Transmission electron microscopy, combined with the ability to gain direct crystallographic information from associated selected-area electron diffraction patterns, represents perhaps the most effective means for the investigation of the nature and behavior of grain boundaries in solids.Any segment of a grain boundary has associated with it five degrees of freedom. The electron microscope has the capability to characterize these degrees of freedom and to uniquely define the geometrical and crystallographic nature of a grain boundary. In addition, once the true geometry of intersecting grain boundaries or grain boundaries intersecting with other interfaces is determined, interfacial free energy ratios can be calculated from which the average energy associated with particular types of interfaces can be determined.
Variation of Lattice Spacing with Thickness of Thin Gold Platelets
Authors: Smart D. C. 
Published: June 2020

Variation of lattice parameters with crystal size in very small crystals (generally less than 500 Å in size) has been the subject of many research papers over a long period of time. In principle this method should provide a direct experimental measurement of surface tension but in many cases the reported results are contradictory. This fact has been noted in recent reviews, and the abnormal spacings are now generally regarded with considerable reserve. The many reported contradictions arise from a variety of experimental factors which cannot be discussed here. This paper, however, reports new experiments using a different approach which we believe has eliminated the previous experimental difficulties, and conclusively demonstrates lattice parameter variations associated with surface energy. These experiments consist of the preparation of thin, parallel, clean and nearly perfect platelets of Au and the subsequent measurement of the lattice spacings of these platelets as a function of thickness.The Au platelets were chemically grown by the reduction of chloroauric acid with salicylic acid. Reproducibly clean crystals from 1-5 µ in diameter and ranging in thickness from 80-300 Å were produced.
Scanning Electron Microscopy of Sintered Copper Spheres
Authors: Nyce A. C. , Wehrung J. M. 
Published: June 2020

Parts produced by the solid state sintering of compacted or loose metal powders are used widely in such critical applications as nuclear reactor control rods and fuel elements, rocket nozzles, corrosion resistant porous filters, automobile parts and many others of equal importance. However, the mechanisms of mass transport responsible for sintering of metal and ceramic powders remain controversial despite over 20 years of experimental and theoretical studies (1) and (2).In an effort to elucidate the mechanisms of solid state sintering, Nyce and Liebenthal determined neck growth, shrinkage, B.E.T. surface area, and sintered strength for nominal 48 and 115 micron diameter, nitrogen-atomized, spherical copper particles containing less than 0.2% oxygen. These relationships were determined as a function of sintering time at temperatures of 850°C and 950°C. Nyce and Liebenthal found by assuming a) microscopically smooth surfaces, b) fracture occurring at necks, and c) reasonably uniform necks between spherical particles that strength, shrinkage, and neck growth could be quantitatively described in terms of B.E.T. surface area measurements.
Chloroplast Abnormalities Seen in a Pale Green Mutant of Chlamydomonas reinhardtii
Authors: Symmes Nancy J. , Weaver Ellen C. 
Published: June 2020

In the search for life support systems for possible long term manned space flights one must, at some point, investigate photosynthetic systems, and hence the interest in green algae with their ease of care, rapid growth rates, and high efficiency of energy conversion. With the present restriction of weight it would be most advantageous to find an organism with a maximum photosynthetic capability.A pale green mutant Ac 29 of Chlamydomonas reinhardtii (obtained from Professor Wilbur Ebersold, UCLA) has been studied which has four times the photosynthetic capacity at high light intensities on a chlorophyll basis as the wild type (as based on measurements of CO2 uptake and O2 evolution). In order to try to find some basis for the differences in photosynthetic capacity, comparisons were made between wild type (strain 21gr, obtained from Ruth Sager, Hunter College) and mutant at both the ultrastructural and chemical levels.
Ultrastructural Changes in Acutely Rejecting Cardiac Allografts
Authors: Popovic N. A. , Hattler B. G. , Jervis H. R. , Ward P. , Currier C. B. , Alexander J. L. 
Published: June 2020

Cardiac allografts have been shown to elicit both in man and in the experimental animal a vigorous and prompt immune response that is poorly understood and remains the main obstacle to the clinical utilization of the heart in organ transplantation. The present study represents a further attempt to delineate mechanisms of damage in hearts being acutely rejected as studied in an experimental dog model utilizing electron microscopic (EM) and histochemical techniques.The model consisted of canine hearts heterotopically transplanted to the necks of recipient dogs previously immunized to donor tissues by repeated intradermal injections of washed donor spleen cells followed by skin grafts until lymphocytotoxic antibody titers were greater than 1/2000 and white graft reactions were seen. At the time of transplantation, prior to removal of the heart, an initial Silverman needle biopsy was taken from the donor ventricle. During this period the animal was well oxygenated and the heart was beating in a normal sinus rhythm.
Cuticular Folds in three Species of Lycopersicon as Observed by Scanning and Transmission Electron Microscopy
Authors: Spurr Arthur R. 
Published: June 2020

Differences in the architecture of the cuticle of Lycopersicon esculentum, L. peruvianum, and L. pennellii (the cultivated and two wild species of tomato, respectively) were examined by scanning electron microscopy. The cuticle of L. esculentum was also studied by transmission electron microscopy to assist in the interpretation of cuticular folds.For SEM, fresh styles were removed from flowers just prior to anthesis and attached to specimen stubs and promptly observed. For TEM, the material was fixed in glutaraldehyde-Os04, dehydrated in ethanol, embedded in epoxy resin, and section-stained with uranyl and lead acetates. Observations were confined to the upper portion of the style.
Purification, Physical Features, and Electron Microscopy of Celo Virus
Authors: Stenback W. A. , Anderson J. P. , McCormick K. J. , Trentin J. J. 
Published: June 2020

Chicken-embryo-lethal-orphan (CELO) virus is an avian adenovirus shown to be oncogenic in newborn random bred and inbred hamsters (1). Transformation of human cells by this agent has been reported (2). This virus is ubiquitously present in chickens and market eggs and is therefore considered to be a potential candidate for cancer etiology in man.Virus for the present study was inoculated into 10-day CELO-free embryonated eggs, and crude stocks consisted of 72-hr allantoic fluid harvests. To 80 ml of crude stock was added 0. 8 gm Na-deoxycholate and 4. 0 ml of 0. 25% trypsin, and the mixture incubated at 37 C for 30 min.
Modular Concepts in the Design of Electron Optical Systems
Authors: Fairbanks J.R. 
Published: June 2020

A practical approach to the design of complex machinery is to standardize parts as much as possible. This approach is equally valid for the design of scientific instruments such as electron microscopes, provided there is no sacrifice in performance for the completed instrument. As an example, the illustration shows modular parts used elsewhere in an electron optical column, which are organized by design in this particular case to perform as a second condenser lens.Consider the upper polepiece. This modular piece is used in nine other places in the column; once in the lower condenser as shown, twice in the upper condenser, twice in the objective lens, twice in the second projector, twice in the third projector, and once in the first projector. Since all the polepieces are identical, they are all of the highest quality needed in the most critical lens, the objective. The optical system thus benefits from standardized high quality lenses, (which ultimately is the user's benefit), and the instrument maker benefits from the economy of making pieces in replicate.
The Effect of Chromatic Aberration on the Visibility of Defect Clusters in Irradiated Metals
Authors: Noggle T. S. , Oen O. S. , Crump J. C. 
Published: June 2020

In recent years considerable attention has been directed to the interrelation of chromatic aberration and energy loss on the resolution of electron microscopes; however, the related problem of the effect of chromatic aberration and energy loss on the visibility of defect structures appears to have not been considered and is the subject of this paper.Electron microscope studies of the defect clusters present in fast neutron irradiated copper and heavy ion irradiated gold have shown that the apparent cluster size distributions are affected by changes in the specimen thickness, accelerating voltage, objective focal length and aperture size in a manner that indicates that chromatic aberration in conjunction with the energy spread due to energy loss of the image forming electrons is responsible for the differences noted. Figure 1 shows cluster size distributions for fast neutron irradiated copper and heavy ion irradiated gold in which it is clear that the apparent densities of cluster sizes less than about 50 Å in diameter are affected by the experimental parameters noted above. The qualitative effect of the experimental parameters on the apparent densities of the smaller defect clusters follows closely the behavior expected from calculations of the radius of the disc of confusion using the equations shown in Fig. 1 and tabulated in the tables. The curves in Fig. 1 indicate that there is no sharp cutoff in the cluster density, and accordingly, it is not clear what criteria should be employed in relating the experimental parameters to the experimental results.
Determination of the Axial Poisson’s Ratio For 1 Mil Nylon and Polyester Fibers Using the SEM
Authors: Hubbard James L. , Rushing Eugene V. 
Published: June 2020

A technique has been devised for measuring the axial Poisson's ratio, vLT, of 1 mil transversely isotropic man-made polymeric fibers using the scanning electron microscope. This study was a part of a larger one in which techniques were developed for measuring the five independent elastic constants necessary to describe the mechanical behavior of such fibers.To facilitate the making of these measurements a stressing stage was constructed for the Cambridge Stereoscan Mark II. This stage, shown in Figure 1 replaces the normal sample block in the specimen chamber drawer and utilizes the normal tilt and rotation controls to tilt the stage and activate the stressing jaws respectively.