bluuebunny/crossref_metadata_2025_split huggingface dataset:
CVD of Al2O3 Thin Films Using Aluminum Tri‐isopropoxide
Authors: Blittersdorf S. , Bahlawane N. , Kohse‐Höinghaus K. , Atakan B. , Müller J. 
Published: August 2003

AbstractA stagnation point cold‐wall reactor was used for the CVD of corundum alumina (α‐Al2O3) on metallic substrates. Depositions were carried out under low pressure using the thermally induced pyrolytic oxidation of aluminum tri‐isopropoxide (ATI). The effects of the substrate temperature (300–1080 °C) and the total pressure (50–250 mbar) on the growth rate and morphology of the deposits were investigated. An excess of oxygen facilitates the formation of dense alumina films. Precursor depletion was prevented using high gas velocity, low ATI concentration, and a high temperature gradient. X‐ray diffraction (XRD) analysis provided evidence of corundum alumina deposition at substrate temperatures above 1000 °C.
ZrO2 Thin Films Grown on Silicon Substrates by Atomic Layer Deposition with Cp2Zr(CH3)2 and Water as Precursors
Authors: Putkonen M. , Niinistö J. , Kukli K. , Sajavaara T. , Karppinen M. , Yamauchi H. , Niinistö L. 
Published: August 2003

AbstractZrO2 thin films have been deposited onto (100) silicon substrates by atomic layer deposition (ALD) using Cp2Zr(CH3)2 (Cp = cyclopentadienyl) and water as precursors at 200–500 °C. Optimal results were obtained at 350 °C, with a deposition rate of 0.43 Å (cycle)–1. Films deposited at 300–400 °C were polycrystalline, with monoclinic ($ \bar 1 $11) as the preferred orientation. Carbon and hydrogen impurity levels in the films deposited at 350 °C were below the detection limit (0.1 at.‐%) of time of flight elastic recoil detection analysis (TOF‐ERDA). Dielectric properties of the deposited films were also determined. According to the high‐resolution transmission electron microscope (HRTEM) analysis, 5 nm thick ZrO2 films were uniform when deposited onto untreated Si(100).
An image analysis‐based approach for automated counting of cancer cell nuclei in tissue sections
Authors: Loukas Constantinos G. , Wilson George D. , Vojnovic Borivoj , Linney Alf 
Published: August 2003

AbstractBackgroundSemiquantitative evaluation and manual cell counting are the commonly used procedures to assess positive staining of molecular markers in tissue sections. Manual counting is also a laborious task in which consistent objectivity is difficult to achieve. Recently, image analysis has been explored, but the studies reported were limited to histological images acquired at high magnification and containing uniformly stained cells.MethodsThe analyzed material consisted of histological sections from different squamous cell cancers that had stained for proliferation using Ki‐67 and cyclin A detection. The first step of the method was based on detecting the overall number of cells irrespective to their stain, using second‐order edge detection methodology. Then proliferating cells were located using principal component analysis (PCA) of the color image, combined with histogram thresholding.ResultsThe algorithms' performances were validated on tissue section images encountered in routine clinical practice by comparison with objective measures of performance and manual cell identification. The algorithms correlated closely with manual counting of all cells (r2 = 0.96–0.97) and stained cells (4–7% cell count error).ConclusionsCell counting in complex large‐scale histological images could be applied in routine practice using edge and color information. The proposed technique provides several benefits, such as speed of analysis, consistency, and automation. Moreover, it is faster than human observation and could replace the laborious task of manual cell counting. Cytometry Part A 55A:30–42, 2003. © 2003 Wiley‐Liss, Inc.
Variation of the genome size estimate with environmental conditions in Drosophila melanogaster
Authors: Nardon Christiane , Weiss Michèle , Vieira Cristina , Biémont Christian 
Published: August 2003

AbstractBackgroundGenome size is known to exhibit interspecies differences, but also to vary between populations within a given species and even between individual cells within an organism. Major differences have often been reported and attributed to differences in measurement conditions, in internal controls of genome size, and in the stains used. Flow cytometry using intercalating dyes is the most attractive method for measuring genome size.MethodsWe estimated relative genome size of nuclei from heads of Drosophila melanogaster adult males using a FACScalibur flow cytometer and propidium iodide.ResultsWe have shown that the genome size estimates depended on the temperature and humidity of the rearing medium and decreased with age in adult flies. There were large differences in genome size estimates between the vials in which the flies were maintained, but only slight variations within the vials, supporting the idea that the size estimate depends on the fly rearing conditions. Changes in the temperature of the solution of head nuclei analyzed by the cytometer also influenced the genome size estimate.ConclusionsThese findings clearly show that the environmental conditions under which the flies were reared influence the genome size estimate, perhaps as a result of a change in the accessibility of the DNA to the fluorochrome. Caution is therefore called for when estimating genome size. Experimental artifact rather than adaptation may account for some of the correlations between genome size and environmental conditions reported in the literature. Cytometry Part A 55A:43–49, 2003. © 2003 Wiley‐Liss, Inc.
Telomere length measurements in leukocyte subsets by automated multicolor flow‐FISH
Authors: Baerlocher Gabriela M. , Lansdorp Peter M. 
Published: August 2003

AbstractBackgroundTelomeres are essential protein‐DNA structures at the end of chromosomes which are implicated in genome stability and cell replication. The average length of telomere repeats can be measured by in situ hybridization and flow cytometry [flow‐FISH]. Such telomere length values reflect telomere shortening (resulting from cell divisions, oxidative damage and other causes) and telomere elongation (mainly resulting from telomerase activity) of the chromosome‐specific telomere length inherited in the gametes. Here we report improvements in flow‐FISH methodology that enable measurements of telomere length in subsets of human nucleated blood cells.Methods and ResultsIn order to measure the telomere length in granulocytes, naive T cells, memory T cells, B cells and natural killer (NK)/NKT cells within a blood sample, we combined flow‐FISH with antibody‐staining (Multicolor flow‐FISH). Most steps in the staining protocol were automated using a 96‐well microdispenser device. The minimum detectable difference in telomere length and the reproducibility of the method are in the range of 0.2–0.5 kb and measurements can be made with as few as a thousand cells.ConclusionsAutomated multicolor flow‐FISH will greatly facilitate studies of telomere length regulation in subsets of nucleated blood cells, especially when only few cells are available and when differences in telomere length are small. Cytometry Part A 55A:1–6, 2003. © 2003 Wiley‐Liss, Inc.
An analysis of changes in the expression of cyclins A and B1 by the cell array system during the cell cycle: Comparison between cell synchronization methods
Authors: Takita Morihito , Furuya Tomoko , Sugita Tomoya , Kawauchi Shigeto , Oga Atsunori , Hirano Takashi , Tsunoda Shinichi , Sasaki Kohsuke 
Published: August 2003

AbstractBackgroundA novel high‐throughput analysis, cell array system, was developed for an extensive study of the expression of genes and/or the degradation of gene products at the cellular level. To exemplify the usefulness of this system, we showed the changes in the expression level of cyclin A and B1 during the cell cycle in a single experiment.MethodsWe used the cell array system to chase the changes in cyclin A and B1 expression during the cell cycle in HeLa cells. Cells were synchronized by mitotic selection and thymidine‐hydroxyurea methods. Cells were harvested at intervals of 1 h from 0 through 23 h. These 48 cell samples were spotted on a circle of the cell array glass slide. Cyclin A and B1 were immunologically stained with Alexa Fluor 488, and nuclear DNA was stained with propidium iodide. The amount of cyclins and nuclear DNA were simultaneously measured by a laser scanning cytometer.ResultsBoth cyclins were expressed in a cell cycle‐dependent manner as previously reported. The precise time‐course of the expression level of cyclins were obtained at a single experiment with this cell array system.ConclusionsThis study indicates that the cell array system is valuable to analyze temporal course of protein expression in relation to the cell cycle position and, that it facilitates antigen expression studies at the cellular level in multiple samples. Cytometry Part A 55A:24–29, 2003. © 2003 Wiley‐Liss, Inc.
A new nondestructive cytometric assay based on resazurin metabolism and an organ culture model for the assessment of corneal viability
Authors: Perrot Sébastien , Dutertre‐Catella Hélène , Martin Chantal , Warnet Jean‐Michel , Rat Patrice 
Published: August 2003

AbstractBackgroundThree‐dimensional culture or human corneal equivalents for safety testing are difficult to investigate with classic cytometric or biochemical methods. So a fluorometric method is proposed using resazurin probe.MethodsAbsorbance and fluorescence spectra of the oxidized and reduced forms of resazurin were performed to determine optimal measurement conditions. More than 100 enucleated porcine eyes were used for this experiment. Twelve corneas were immersed in resazurin solution and fluorescence was measured hourly from 1 to 10 h. Ninety benzalkonium chloride–treated corneas and control corneas were used as toxicity controls, and corneal viability was compared with in vivo rabbit eye irritation.ResultsAfter analysis of spectra, the optimal measurement condition of resazurin metabolism proved to be a fluorescence measurement using 570 nm excitation wavelength and 590 nm emission wavelength. The reduction of resazurin was optimal after 6 h of incubation. Resazurin metabolism by isolated pig corneas varied proportionately with the benzalkonium chloride concentration employed, clearly showing significant differences (P < 0.001) in agreement with the in vivo data.ConclusionThe resazurin metabolism test can be used to evaluate corneal viability and can thus be a potential alternative for toxicological assessments. This assay allows rapid assessment of non destructed samples, with simple equipment and at a reduced cost for continuous monitoring of corneal viability and possibly other three‐dimensional cellular models. Cytometry Part A 55A:7–14, 2003. © 2003 Wiley‐Liss, Inc.
Staurosporine‐induced apoptosis in human cornea epithelial cells in vitro
Authors: Härtel Steffen , Zorn‐Kruppa Michaela , Tykhonova Svitlana , Alajuuma Päivi , Engelke Maria , Diehl Horst A. 
Published: August 2003

AbstractBackgroundApoptosis is a an important process in corneal development, homeostasis, and disease. This study was performed to determine for the first time basic temporal apoptotic features of SV‐40 immortalized human corneal epithelial (HCE) cells. Additionally, we introduce a sensitive analysis of confocal microscopic images to measure the kinetics of staurosporine (STS) induced phosphatidylserine (PS) membrane translocation and early nuclear morphological changes.MethodsHCE cells were cultured in the presence of STS to induce apoptosis. Caspase‐3 activity was measured with the fluorogenic substrate z‐DEVD‐rhodamine 110. We determined mitochondrial viability with a 4‐[3‐(4‐iodophenyl)‐2‐(4‐nitrophenyl)‐2H‐5‐tetrazolio]‐1,3‐benzenedisulfonate reduction assay, and chromatin degradation with a fluorometric method using 4,6‐diamidino‐2‐phenylindole (DAPI). Membrane translocation of PS and nuclear alterations were assessed by quantitative fluorescence microscopy. Image processing routines were written in interactive data language (IDL).ResultsNuclear alterations like hyperchromicity, pyknosis, and active chromatin reorganization evolved instantly after STS induction. They were followed by PS translocation, DNA fragmentation, mitochondrial breakdown, and caspase‐3 activation, which were detected between ≈90 min and 4 h.ConclusionsMorphological and texture sensitive descriptors proved to be highly susceptible for the quantification of early apoptotic nuclear characteristics in HCE cells. We propose this method to be considered for the detection of subtle nuclear reorganization in cellular studies. Cytometry Part A 55A:15–23, 2003. © 2003 Wiley‐Liss, Inc.
Interactions of fluorochrome‐labeled caspase inhibitors with apoptotic cells: A caution in data interpretation
Authors: Pozarowski P. , Huang X. , Halicka D. H. , Lee B. , Johnson G. , Darzynkiewicz Z. 
Published: August 2003

AbstractBackgroundFluorochrome‐labeled inhibitors of caspases (FLICA, e.g., FAM‐VAD‐FMK, FITC‐VAD‐FMK) have been designed as affinity labels of the enzyme active center of caspases Their binding by apoptotic cells was interpreted as reflecting activation of caspases. We have recently observed, however, that their binding is more complex and may involve additional mechanisms. Our goal in this study was to clarify the ongoing utility of these probes.MethodsApoptosis of HL‐60, Jurkat, MCF‐7 and T‐24 cells was induced by the DNA topoisomerase I inhibitor, topotecan, or by oxidative stress (H2O2). Lymphocytes were induced by their mitogenic activation. Using multiparameter laser scanning and flow cytometry analysis, the correlation between FLICA binding and the number of known apoptotic indicators was examined. These included: collapse of the mitochondrial transmembrane potential; activation of caspase‐3 (detected immunocytochemically); binding of annexin V; chromatin condensation; the presence of DNA strand breaks; and loss of plasma membrane capability to exclude propidium iodide (PI). FLICA binding specificity was tested by pretreatment with z‐VAD‐FMK or z‐DEVD‐FMK.ResultsFLICA binding was subsequent to the collapse of mitochondrial transmembrane potential, nearly concurrent with caspase‐3 activation, and preceded annexin V binding, chromatin condensation, DNA fragmentation and loss of plasma membrane integrity. The predominant portion of FAM‐VAD‐FMK, FITC‐VAD‐FMK or FAM‐DEVD‐FMK binding to apoptotic cells could not be inhibited by z‐VAD‐FMK or z‐DEVD‐FMK, respectively, when the unlabeled inhibitors were added post‐induction of apoptosis.ConclusionsFLICA are specific and convenient to use markers of apoptotic cells and they detect very early events of apoptosis associated with caspases activation. Assays that combine their binding with either the loss of mitochondrial potential or with exclusion of PI as a probe of plasma membrane integrity, distinguish sequential stages of apoptosis and are particularly useful to differentiate between apoptosis and necrosis. Our results conform with the published data that unlabeled caspase inhibitors, when added after induction of apoptosis, cannot prevent activation of caspases detected by binding of biotinylated inhibitors or by cleavage of fluorogenic substrates. While FLICA binding by apoptotic cells most likely is a consequence of caspase activation, these binding events may also involve other or additional mechanisms than simply their specific attachment to the active enzyme centers of caspases. Cytometry Part A 55A:50–60, 2003. © 2003 Wiley‐Liss, Inc.
A voltage‐controlled cmos phase‐shift oscillator for short‐range wireless communications
Authors: Nakamura Mitsuo , Matsuoka Toshimasa , Taniguchi Kenji 
Published: August 2003

AbstractThis paper presents a voltage‐controlled CMOS phase‐shift oscillator which can output a sinusoidal signal with a simple circuit configuration requiring no on‐chip inductor, which is intended for use in short‐range wireless communications such as a chip‐to‐chip wireless communications interface. A CMOS phase‐shift oscillator is experimentally fabricated by a 0.6‐µm CMOS process, with an oscillation frequency of approximately 600 MHz. Characteristics such as harmonics, the tuning range of the oscillation frequency, and phase noise are examined, and it is found that the proposed voltage‐controlled CMOS phase‐shift oscillator can be used in short‐range wireless communications, thus drastically reducing the circuit size. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(9): 24–30, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10080
Floating voltage reference generator for A/D converters
Authors: Ogawa Toru , Ozeki Toshiaki , Taniguchi Kenji 
Published: August 2003

AbstractWe propose a circuit for generating a floating reference voltage required by a pipeline A/D converter having a differential configuration. This circuit uses the bipolar transistor and resistor ratios to generate any floating voltage having an arbitrary common‐mode voltage and small temperature and source voltage dependencies. A simulation of the proposed circuit fabricated by the 0.25‐µm CMOS process demonstrated ±1.5 mV output floating voltage fluctuations in the temperature range of −50 to 100 °C. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(9): 20–23, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10117
A study on electron‐wave filters using barrier height modulated multiple barrier structures
Authors: Sanada Hirofumi , Watanabe Kazuhisa 
Published: August 2003

AbstractThe one‐dimensional semiconductor multiple barrier structure playing a role of a filter for electron waves is important as a configuration to control the behavior of the electrons in electron‐wave devices. Recently, many theoretical and experimental reports on the subject have been presented. Since the electron‐wave filter characteristics are directly affected by the potential shape, it is important to systematically understand the relationship between the potential shape and the realizable characteristics so that desired characteristics can be realized. In this paper, the circuit‐theoretical design of a potential barrier height modulated electron‐wave filter is discussed. It is shown that an electron‐wave filter with a bandpass characteristic can be realized. Also, the designed electron‐wave filter is shown to be superior in terms of the transmission coefficients and group delay in the passband in comparison to the periodic multiple barrier structures. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(9): 11–19, 2003; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecjb.10133
An integration design of compact E‐plane multiway waveguide power dividers
Authors: Kishihara Mitsuyoshi , Ohta Isao , Kawai Tadashi , Yamane Kuniyoshi 
Published: August 2003

AbstractIn this paper, E‐plane multiway waveguide power dividers consisting of many steps, many sections, and corners are treated. Practical dividers with a small size and a broad bandwidth are designed. In general, in a structure with various discontinuities placed close together, it is necessary to take into account the mutual interactions among the propagating and nonpropagating modes. The design method based on the E‐plane planar circuit approach and the segmentation/desegmentation method used in this paper can provide accurate circuit characteristics with simple matrix calculations. Therefore, optimal design of a circuit configuration consisting of several discontinuities can be performed within a short time. First, the trifurcated and tetrafurcated dividers for the X band are designed. Next, an integrated design is attempted for three‐ and fourway dividers with mitered bends at the output ports. As a result, flat power dividing characteristics over the entire X‐band are obtained. The validity of the present design method is confirmed by means of an electromagnetic field simulator (HFSS) and trial experiments. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(9): 1–10, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10151
Attenuation map reconstruction using topology constrained labeling
Authors: Kudo Hiroyuki , Nakamura Hiroki 
Published: August 2003

AbstractIn order to derive a quantitative reconstructed image in various types of emission CT (ECT), such as SPECT and PET, it is necessary to examine the gamma ray attenuation coefficient distribution inside the body, called the attenuation map, by transmission CT (TCT), and to apply attenuation correction. This paper proposes a new method in which the attenuation map is reconstructed from the incomplete TCT projection data or ECT projection data. The conventional attenuation map reconstruction method is performed, assuming that each pixel of the attenuation map takes a continuous value. In the proposed method, in contrast, the attenuation map is reconstructed by region segmentation in which the pixel value takes only discrete values. The problem is formulated as a labeling problem in which the label image minimizing the energy function is to be determined. In order to avoid local minima, the solution is derived by stochastic relaxation. In the conventional formulation of image region segmentation, however, the search space for the solution is too wide, and it is difficult to derive an accurate attenuation map if the measured data are incomplete. Consequently, this paper proposes topology constrained labeling, in which topology constraints, that is, a priori information on the topology (the number of regions and the connection relations among the regions) of the attenuation map to which the region segmentation is applied, are used, and the solution search space is constrained. Simulation experiments, as well as an experiment using the actual PET data, were performed, and the effectiveness of the topology constrained labeling has been demonstrated. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(9): 31–41, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10179
Classroom support and system administration support for large‐scale educational computer system
Authors: Saitoh Akinori , Nishida Tomohiro , Nakanishi Michio , Yasutome Seigo , Baba Ken‐ichi , Shigehiro Yuji , Harada Akira , Yamai Nariyoshi , Matsuura Toshio 
Published: August 2003

AbstractUniversity and other educational computer systems may have several thousands to several tens of thousands of users, and several hundreds to several thousands of terminals. When the scale of the system is enlarged, not only is the burden of management increased, but various problems are produced in the system configuration and administration due to the character of the educational system, in which many identical manipulations are performed at the same time. This study was performed in the educational computer system of the Osaka University Information Processing Education Center (now the Cybermedia Center). Through the design and development of a system to support smooth administration of the computer system and classroom activities in the center, the functions needed for support were organized and practical problems were identified, together with methods for their solution. The new system was operated at the Osaka University Information Processing Education Center and was found to contribute greatly to classroom and administration support. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(9): 42–52, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10180