bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow Injection Analysis of Mixtures of Dopamine, Adrenaline and Ephedrine in Human Biofluids Using Stabilized after Storage in Air Lipid Membranes with a Novel Incorporated Resorcin[4]arene Receptor
Authors: Nikolelis Dimitrios P. , Siontorou Christina G. , Theoharis George , Bitter István 
Published: February 2005

AbstractThis work describes a technique for the rapid, selective and sensitive electrochemical flow injection analysis of mixtures of the stimulating compounds adrenaline, dopamine, and ephedrine using stabilized after storage in air bilayer lipid membranes (BLMs) with incorporated resorcin[4]arene receptor. Injections of the stimulating compounds were made into flowing streams of a carrier electrolyte solution and a transient current signal, with duration of seconds, reproducibly appeared in less than two min after exposure of the lipid membranes to the compounds. The magnitude of this signal was linearly related to the concentration of the compound, which could be determined at micromolar levels. Repetitive cycles of injection of stimulating compounds have shown no signal degradation during each cycle (30 sequential injections). The time of appearance of the transient response was different for each stimulating compound and increased in the order of adrenaline, dopamine and ephedrine. The difference in time of response has allowed selective detection and analysis of these compounds in mixtures. The investigation of the effect of potent interferences included a wide range of compounds usually found in human biofluids, as well as proteins and lipids. The results showed that only proteins (most common in lipid film based biosensors) pose a problem that can be eliminated by modulation of the carrier solution to flow rates that do not allow adsorption of these compounds in the lipid films. The technique was applied in human urine samples.
Application of a Carbon Paste Electrode Modified with a Schiff Base Ligand to Mercury Speciation in Water
Authors: Colilla Montserrat , Mendiola M. Antonia , Procopio Jesús R. , Sevilla M. Teresa 
Published: February 2005

AbstractA carbon paste electrode, modified with benzylbisthiosemicarbazone is used for mercury speciation in water samples. Mercury ion is selectively accumulated on the electrode surface at open circuit and its analysis was performed by cyclic voltammetry or square‐wave voltammetry (SWV). A detection limit of 8 μg L−1 (3σ) was found for 15 min of accumulation using SWV as measurement technique. The effect of several metallic ions and organic substances on voltammetric signal is examined. For speciation purposes, a ligand competition methodology between ligands in solution and electrode is used. Model mercury complexes are characterized as a function of their dissociation kinetics. The method was applied to mercury speciation in water samples from the Jarama River in Madrid.
Sarbanes‐Oxley: Will you need a forensic accountant?
Authors: Christensen Jo Ann , Byington J. Ralph , Blalock Tonya J. 
Published: February 2005

AbstractThe Sarbanes‐Oxley Act forces top management to certify that financial statements are free of fraud and material misstatement. Just using an independent auditor may not be enough. The authors explain why adding a forensic accountant to an audit team is an advantage—and might have saved the careers of some high‐profile cor‐porate executives. © 2005 Wiley Periodicals, Inc.
STEM imaging of thick specimens with off‐axis detectors
Authors: Cowley J. M. 
Published: February 2005

AbstractFor scanning transmission electron microscopy (STEM) images obtained with relatively small objective aperture sizes, the contrast of small objects contained within thick specimens may be considerably enhanced by using an off‐axis detector aperture situated on the edge of the central beam spot. The effect is demonstrated for both crystalline and amorphous specimens. The effect arises because the detector collects part of the small angle inelastic scattering and is modified by refraction effects for specimens of rapidly changing thickness.
Computer simulation and analysis of high‐resolution electron microscope images and diffraction patterns with partial coherence, hollow cone illumination, and virtual apertures
Authors: Krakow William 
Published: February 2005

AbstractA general method for computing high‐resolution conventional transmission electron microscope images and diffraction patterns, when there are different types of partially coherent illumination conditions, is described. Examples of convergent beam, hollow cone, and virtual aperture illumination conditions are given in the context of interpreting image features. A comparison of real and computed diffraction patterns shows that, in practice, many innovative imaging modes are possible, which can be verified prior to real microscope experiments.
Rapid freezing, cryosectioning, and x‐ray microanalysis on cardiac muscle preparations in defined functional states
Authors: Wendt‐Gallitelli Maria‐Fiora , Wolburg Hartwig 
Published: February 2005

AbstractElectrically stimulated heart muscle preparations can be quickly frozen in undercooled propane at defined times of the mechanically controlled contraction cycle. The apparatus for triggered freezing of the muscle strips in undercooled propane is described in detail. Freeze substitution of some strips after freezing shows the degree of ice crystal formation without the potential interference of artifacts introduced later by cryosectioning and freeze drying. Ultrathin longitudinal and transversal cryosections are cut with a LKB cryoultramicrotome at temperatures of −130 to −140°C, freeze‐dried at 10−6 Torr vacuum and carbon‐coated before analysis. The freeze‐dried cryosections are analyzed in a Siemens Elmiskop 102 electron microscope equipped with a Kevex energy dispersive system, and the elemental concentrations (in mMol/kg d.w.) of Na, Mg, P, S, Cl, K, and Ca are determined in subcellular compartments of muscle frozen in different functional states. The methodology of quantitation, i.e, determination of elemental net peak and continuum, correction of continuum, preparation of standards, and deconvolution of overlapping peaks are described. The minimum detectable elemental concentration using the reported methods is in the range of a few mMol/kg d.w. This also applies to Ca, which can be accumulated in heart muscle in readily detectable amounts in intracellularly located stores as well as structures connected with the cell membrane. The present report shows that cryotechniques and x‐ray microanalysis can be successfully applied to heart physiology.
The preparation of cultured cells of vascular origin for transmission electron microscopy
Authors: Purdy‐Ramos Susan I. , Forbes M. S. 
Published: February 2005

AbstractA method is described for obtaining optimal, reproducible ultrastructure of vascular smooth muscle cells and vascular endothelial cells in culture. Routinely grown cultures are prepared for TEM with a precise regimen of fixation, postfixation, en bloc staining, dehydration, and embedment. The most important aspects of this procedure are the following: (1) fixation with a percentage‐gradient series of glutaraldehyde solutions at 37°C, (2) immediate postfixation with osmium tetroxide solution, and (3) block‐staining with uranyl acetate solution to eliminate any extraction of constituents during subsequent processing.
Surface‐replica cytochemistry as a tool for studying cell‐surface enzyme activity: Membrane ecto‐ATPase localization in liver cell cultures
Authors: Karasaki Shuichi , Tanaka Akira 
Published: February 2005

AbstractA stain‐replica technique is described for cytochemical examination of ecto‐adenosine triphosphatase (ATPase) activity over the membrane surface of monolayer cell cultures. Rat liver epithelial cells grown on a plastic substrate were fixed in glutaraldehyde, incubated in situ in an ATPase‐lead reaction medium, ethanol‐dehydrated and air‐dried. The cell surface of the monolayer cultures was replicated with plasma polymerization of hydrocarbon gas in the negative phase of glow discharge. X‐ray microprobe analysis confirmed the site‐specific deposition of lead phosphate in the polymer‐replica films. The cytochemical localization of lead was mirrored in the replicas of epithelial cells, demonstrating that ATPase activity was expressed along the apical margins of cell‐to‐cell contacts. Little or no activity was present over the remainder of the smooth‐surface membranes. In transformed epithelial cells, there were abundant reaction products over the microvilli and intercellular boundaries. These observations were consistent with biochemical data on the liver epithelial cells in culture and suggested the potential of surface‐replica cytochemistry.
Preparation of biological tissue sections for correlative ion, electron, and light microscopy
Authors: Kupke K. G. , Pickett J. P. , Ingram P. , Griffis D. P. , Linton R. W. , Burger P. C. , Shelburne J. D. 
Published: February 2005

AbstractIn order to correctly interpret the chemical images obtained using ion microscopy (IM), it is useful to correlate them with the information provided by conventional light microscopy (LM), secondary electron imaging (SEI), backscattered electron imaging (BEI), and electron probe microanalysis (EPMA). Accordingly, we have devised a technique of specimen preparation which allows for the application of several different microanalytical techniques to a single histologic section mounted on the same substrate. Sections are cut onto polyester plastic coverslips (devoid of peaks for any element with atomic number > 9 using EPMA) and studied by LM. After a light rotary coating with carbon (to prevent charging), the section can then be examined by SEI, BEI, and EPMA. Specific areas can be marked for IM study either with an objective‐mounted pin tissue microlocater, or by placing small pieces of metal foil, cut in specific geometric shapes, over features of interest. After sputter‐coating the sample with platinum, metal‐free shadows are visible using a low‐power reflected light microscope available on a typical IM sample chamber as a guide for ion beam placement. The conductive coatings also minimize specimen charging during IM. Post‐IM light microscopy, SEI, and BEI are used to confirm the location of specific areas probed in the IM experiments and to provide information on differential ion‐sputtering artifacts and tissue contaminants. This new correlative technique should permit better understanding of the images obtained with these diverse instruments.
Localization of opioid binding sites in rat brain by electron microscopic radioautography
Authors: Hamel Edith , Beaudet Alain 
Published: February 2005

AbstractTwo met‐enkephalin analogs (FK 33–824 and FW 34–569, Sandoz) were utilized for in vitro labeling of opioid binding sites in the rat central nervous system. Binding kinetics determined in 20‐μm‐thick frozen tissue sections of the striatum revealed that both pentapeptides bind to a single population of sites at 20°C with an apparent dissociation constant (KD) of approximately 1–2 nM and a maximum capacity (B max) of 65–170 fmoles/mg protein. Radioautographic data suggest that this population is the same for iodinated and tritiated forms of the FK compound and the iodinated FW analog. Fixation of labeled sections with high concentrations of glutaraldehyde allowed proportional retention of more than 50% of specifically bound 125I‐FK molecules in all brain regions after histological processing for high‐resolution radioautography. In contrast, glutaraldehyde fixation did not prevent the loss of bound 125I‐FW molecules. These differences are attributed to the presence in FK, but not in FW molecules, of a free primary amino group considered essential for cross‐link formation between aldehydes and proteins, and imply that a majority of FK‐receptor complexes may be stabilized by glutaraldehyde. Consistent with this observation is the fact that the radioautographic distribution of specifically bound 125I‐FK was unchanged after fixation and dehydration. In electron microscopic radioautographs prepared from prefixed, vibratome‐cut striatal sections that were incubated with 125I‐FK and fixed with glutaraldehyde, silver grains were found to be mostly associated with neuronal plasma membrane interfaces. The present methodological approach thus appears to be compatible with electron microscopic localization of opioid binding sites in the central nervous system and might be applicable to the localization of other types of binding sites using radioligand molecules that contain a free primary amino group.
Scanning electron microscopy of vascular casts
Authors: Burger Peter C. , Chandler David B. , Klintworth Gordon K. 
Published: February 2005

AbstractCorrosion casts provide three dimensional replicas that can be examined readily by scanning electron microscopy (SEM). They are prepared by filling vascular networks with polymerizing plastic and then digesting away the tissue. As based on our studies of ocular vessels, this report describes the vascular anatomy, as well as the artifacts, that are encountered during SEM studies of such preparations.
Enzyme‐gold electron microscopic cytochemistry: A new affinity approach for the ultrastructural localization of macromolecules
Authors: Bendayan Moïse 
Published: February 2005

AbstractThe enzyme‐gold postembedding approach has been introduced recently in the field of cytochemistry for the ultrastructural localization of macromolecules. This technique is based on the affinity properties existing between an enzyme and its substrate. The possibility of detecting substrate molecules by applying enzyme‐gold complexes has been established. The present review deals with the development and the technical approach of this method. Various applications are reported for the demonstration of the reliability of the technique that yields results of high specificity and resolution. In addition, some technical problems and limitations particular to this method are reported and discussed.
Electron microscopy of semithick sections: Advantages for biomedical research
Authors: Rieder Conly L. , Rupp Gerald , Bowser Samuel S. 
Published: February 2005

AbstractMany transmission electron microscopes are available which can be used to examine biological material in 0.25–0.50‐μm‐thick sections. When compared to the traditional thin section, these “semithick” sections possess a number of inherent advantages: They can be screened for content with the phase contrast light microscope, they facilitate many types of studies requiring an analysis of serial sections, and they are frequently the optimum thickness for stereomicroscopy. Structures such as microtubule‐associated components, as well as structural relationships between cellular constituents, may also be clearly visible in semithick sections which are not visible, or go unnoticed, in thin sections. Together these advantages enable an investigator to obtain a more complete three‐dimensional picture of a cell or cell component in a significantly (i.e., up to 90%) shorter period of time than would be required if thin sections were used. Semithick sections may, therefore, make a study feasible which is not approachable, or which is approachable only with great difficulty, by conventional thin sectioning techniques.
Preparation of carbon films from evaporated fibers and rods at fore‐vacuum pressure
Authors: Namork Ellen 
Published: February 2005

AbstractFore‐vacuum (pressure ≥ 3 Pa) evaporation of carbon fibers and rods to thin films has been tested and the resulting thicknesses recorded. A modified sputter coater was used as a vacuum evaporator. The quality of the carbon films was evaluated by bright‐field and dark‐field electron microscopy. Although high‐vacuum‐evaporated carbon films are superior in quality, low‐vacuum‐evaporated carbon films were found fully acceptable for routine work in bright field, for both TEM and SEM purposes. Apart from being time‐saving, the method presented has the obvious advantage, in SEM preparations, that carbon coating and metal sputtering can be carried out in the same unit without breaking the vacuum.
An application of rapid freezing, freeze substitution–fixation for scanning electron microscopy
Authors: Osatake Hitoshi , Tanaka Keiichi , Inoué Takao 
Published: February 2005

AbstractA combined technique of the rapid freezing, freeze substitution–fixation method and the osmium–DMSO‐osmium method was devised. By this combined method we clearly observed the architecture of intracellular components in three dimensions. Morphological characteristics were generally similar to those of tissue prepared by the osmium–DMSO‐osmium method but different in some respects. Mucigen droplets in intestinal goblet cells, for example, appeared as separated spheres, while in specimens prepared by chemical fixation they were observed as a mass of fused droplets. In the Golgi complex, all cisternae were extremely flat, although they usually dilated on the cis side after chemical fixation. Particles on the mitochondrial tubules of liver cells were well distinguished. They were mushroom shaped, as are those observed by negative staining. The combined method, that is, the rapid freezing, osmium–DMSO‐osmium method, is thought to be effective for studying the true structure of intracellular components by scanning electron microscopy.
A method of noise removal using the inverse transform of an image autocorrelation function
Authors: Baba Norio , Oho Eisaku , Kanaya Koichi 
Published: February 2005

AbstractA method for a reversible transform between an image and image autocorrelation function has been devised, and it has been applied to the reduction of random noise in a microscope image. Object‐related features of an image signal as well as noise features are overlapped at the vicinity of the origin of an image autocorrelation, and a peak is formed at this position. The present method removes the noise contribution in this peak and returns the autocorrelation function, thus corrected, to the image. An autocorrelation function is computed by two Fourier transforms as based on the convolution theorem. The inverse transform from the image autocorrelation function is made possible by performing two Fourier transforms in reverse to the above. This method has been developed to remove random noise more accurately from a single image (especially for nonperiodic images) than other image‐processing methods such as smoothing techniques and low pass filtering.
Quantitative EDS and WDS X‐ray microanalysis of semiconductor materials: Principles and comparisons
Authors: Herrington Charles R. 
Published: February 2005

AbstractThe basic principles and procedures for performing accurate X‐ray microanalyses on semiconductor materials as well as the differences and advantages of EDS (energy‐dispersive spectroscopy) and WDS (wavelength‐dispersive spectroscopy) are presented. Many of the techniques discussed are the result of extensive experience with some photovoltaic materials such as CuInSe2, GaAs, CdTe, CdS, CdSnP, InP, ZnP, and amorphous Si‐based alloys.Results of an experiment designed to compare the performance of an energy‐dispersive X‐ray spectrometer (EDS) and a wavelength‐dispersive X‐ray spectrometer (WDS) on some semiconductor materials are presented. CdTe, CdSe, CuInSe2, ZnSe, and InSb standards were used to measure the k‐ratios with pure element standards employing both types of X‐ray spectrometers to demonstrate the ability of each to measure elemental compositions under various operating conditions. Both types of spectrometers were utilized on a Cameca MBX electron microprobe at identical X‐ray take‐off angles.The EDS spectrometer was found to perform equal to the WDS spectrometer when integral peak‐to‐background ratios were greater than seven, when the X‐ray line being measured was greater than about 1,000 eV, and when adjacent peaks were separated by more than three times the detector energy resolution.
A computer program for the systematic sampling of sections in microscopic morphometry
Authors: Núñez‐Durán Harol 
Published: February 2005

AbstractA computer program is described that facilitates systematic and unbiased sampling in morphometry. Input data are coordinates of the four corners of a section as displayed in the position indicators of the microscope stage. Outputs are coordinate values in the form of a regular lattice that describes where to place the stage and perform the sampling on the section. In addition, some other data are provided by the program, such as total area of section, length of sides, etc. The program is written in BASIC but can be easily converted to other computer languages.
Electron‐beam‐induced current decay measurements in electron probe instruments using a multichannel analyzer
Authors: Yacobi B. G. , Herrington C. R. 
Published: February 2005

AbstractA simple method for decay measurements of the charge collection mode (commonly referred to as electron‐beam‐induced current or EBIC) of an electron probe instrument is presented. The decay, which occurs at continuous electron irradiation, should be distinguished from a decay measurement due to the electron beam blanking. This method could be applied to other modes of an electron probe instrument, e.g., cathodoluminescence, in studying electron‐beam‐sensitive semiconductors. An example of the decay of the EBIC signal in a hydrogenated amorphous silicon device is presented.
Construction and application of a 400 kV analytical atom resolution electron microscope
Authors: Hashimoto Hatsujiro , Endoh Hisamitsu , Tomita Masato , Ajika Natsuo , Kuwabara Masago , Hata Yoshifumi , Tsubokawa Yoshiyuki , Honda Toshikazu , Harada Yoshiyasu , Sakurai Shigekata , Etoh Terukazu , Yokota Yasuhiro 
Published: February 2005

AbstractThe factors defining the resolution limit and the conditions for obtaining images at atomic resolutions are briefly discussed. The construction and performance of a 400 kV analytical atom resolution electron microscope (AARM), and the functions of an energy selecting microscope, X‐ray micro‐analysis, and on‐line image processing systems are described. Some examples of applications of the AARM are shown.
A sorting and searching computer program to index electron diffraction patterns from crystals of low symmetry
Authors: Narayan C. 
Published: February 2005

AbstractElectron diffraction patterns generated from phases that have low crystallographic symmetry are difficult and tedious to analyze by conventional techniques. This paper describes a computation scheme that can index electron diffraction patterns efficiently and quickly and be easily implemented on a personal computer. The technique is based on sorting and searching and is especially useful when rapid analyses of electron diffraction patterns are necessary and the crystalline phase under study has a low symmetry.
A simple method for quick‐freezing
Authors: Bearer Elaine L. , Orci Lelio 
Published: February 2005

AbstractIn conventional freeze‐fracture replicas produced from tissue cryoprotected with glycerol, the hydrophobic inner surfaces of membranes are revealed, but hydrophillic structures are obscured in the surrounding ice. Quick‐freezing of tissue obviates the need for glycerol, which prevents the removal of this ice by etching or freeze‐drying, but the major problem in freezing without glycerol cryoprotection is ice crystal formation. We describe here a simple method for quick‐freezing tissue, in the absence of glycerol, on a nitrogen‐cooled copper block with a hand‐held specimen holder. This method freezes samples well enough to preserve molecular detail that can be revealed by subsequent etching. We show some examples of the quality of this freezing with respect to the visualization of molecular detail in isolated protein molecules such as ferritin and catalase. Furthermore, we show examples of in situ cellular structures that are revealed by this method, and we compare the structure seen in these replicas with structures preserved by quick‐freezing at liquid helium temperatures.