bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphodiesterase 5 inhibitors lower both portal and pulmonary pressure in portopulmonary hypertension: a case report
Authors: Bremer Hinrich C , Kreisel Wolfgang , Roecker Kai , Dreher Michael , Koenig Daniel , Kurz-Schmieg Anna Katharina , Blum Hubert E , Roessle Martin , Deibert Peter 
Published: July 2007

Abstract

Background
Portopulmonary hypertension (PPHTN) is a severe complication in liver cirrhosis. PDE5 inhibitors lower pulmonary arterial pressure (PAP) in PPHTN. However, their effect on portal hypertension has not yet been investigated.

Case presentation
A 55 year old male patient presented with PPHTN and alcoholic liver cirrhosis. 10 mg of Tadalafil, a PDE5 inhibitor with a long half-life, was administered orally under continuous monitoring of pulmonary and portal hemodynamics. For maintenance therapy the patient received Sildenafil 20 mg bid.
Tadalafil lowered mean PAP from 45 to 39 mmHg within 60 minutes. Cardiac output (CO) increased from 6.8 to 7.9 l/min. Central venous pressure (CVP) remained stable at 3 mmHg. Systolic and diastolic blood pressure was lowered from 167/89 to 159/86 mmHg. Pulse rate increased from 75 to 87 per min. Wedged hepatic vein pressure (WHVP) decreased from 21 to 18 mm Hg, hepatovenous pressure gradient (HVPG) decreased from 10 to 7 mmHg. Hemodynamic monitoring after 6 months of Sildenafil therapy revealed a sustained lowering of mean PAP. HVPG remained constant at 10 mmHg. Cardiac and pulmonary performance had further improved.

Conclusion
This case report shows for the first time, that phosphodiesterase 5 inhibitors lower both portal and pulmonary pressure in portopulmonary hypertension.
Crystallization of Amorphous SiO2 Microtubes Catalyzed by Lithium
Authors: Zhao L. , Li N. , Langner A. , Steinhart M. , Tan T. Y. , Pippel E. , Hofmeister H. , Tu K.‐N. , Gösele U. 
Published: July 2007

AbstractAmorphous silica formed by thermally oxidizing silicon is commonly eligible for lithographic patterning or can be grown on patterned substrates. However, it is still a challenge to combine controlled microstructuring with controlled crystallization of SiO2. Here, it is shown that traces of volatile lithium species transported through the gas phase catalyze the crystallization of silica integrated into common silicon microstructures. The selected crystallization temperature determines which polymorph forms. As an example, the formation of quartz, tridymite, and cristobalite microtubes by thermally oxidizing macroporous silicon is investigated. Lithium‐induced crystallization may extend state‐of‐the‐art silicon technology and yield nano‐ and microstructures consisting of different silica polymorphs, which are, in contrast to many functional oxides, nontoxic.
Octahydroxypyridine[4]arene Self‐Assembles Spontaneously To Form Hexameric Capsules and Dimeric Aggregates
Authors: Evan‐Salem Tamar , Cohen Yoram 
Published: July 2007

AbstractIn recent years it has been observed that resorcin[4]arenes and pyrogallol[4]arenes form hydrogen‐bonded hexameric capsules in nonpolar solvents. In the present study we have used NMR spectroscopy, with an emphasis on diffusion NMR, to investigate the self‐assembly and the aggregation mode of solutions of octahydroxypyridine[4]arene (1 b) in chloroform. In spectroscopic studies, the hexameric capsule of C‐undecylresorcin[4]arene (2 b) was used as a reference compound and in some cases also as an internal reference. The current diffusion NMR spectroscopy study shows, in contrast to a previous report, that compound 1 b self‐assembles spontaneously into hexameric and dimeric aggregates in solutions in chloroform. The 1H NMR and diffusion NMR spectroscopic studies on a solution of 1 b in CHCl3 show the presence of new upfield‐shifted peaks, which diffuse with the same diffusion coefficient as the hexameric peaks in the spectrum. Therefore, these new upfield‐shifted peaks were attributed to encapsulated CHCl3 molecules. Interestingly, diffusion NMR measurements showed that the addition of trifluoroacetic acid (6.7 equiv), which had no effect on the hexameric capsules of 2 b, led to the disassembly of the hexamer and the dimer of 1 b into its monomers. Therefore, we conclude that compound 1 b self‐assembles spontaneously into hexameric capsules in nonpolar organic solvents, as do resorcin[4]arenes 2 b and 2 c and pyrogallol[4]arenes 3 a and 3 b.
Recent and Expected Roles of Plasma‐Polymerized Films for Biomedical Applications
Authors: Förch R. , Chifen A. N. , Bousquet A. , Khor H. L. , Jungblut M. , Chu L.‐Q. , Zhang Z. , Osey‐Mensah I. , Sinner E.‐K. , Knoll W. 
Published: July 2007

AbstractThis review aims to provide a summary of some of the challenges in correlating surface science and biology, with particular emphasis on areas where plasma polymerization has and will play an important role as a method to synthesize reproducible and well‐defined surfaces. Since the range of possible applications of plasma polymer films in biomaterial applications is immense, this paper will focus on processes to develop various surface morphologies and chemical structures for the immobilization of proteins and cells. Functional, plasma‐polymerized films are discussed as biosensitive interfaces that may ultimately be part of a multilayer system that aims at connecting inorganic/metallic transducers with biologically reactive surfaces. These topics will be reviewed with some experimental results taken from the authors' own work. Specific aspects such as adhesion improvement and solvent effects are also discussed.
Special Issue on Low‐Pressure Plasma‐Enhanced CVD
Authors: Gordillo‐Vázquez Francisco J. 
Published: July 2007

AbstractLow‐pressure plasma‐enhanced CVD (PECVD) is the topic of this Special Issue of Chemical Vapor Deposition. In this brief introduction, Guest Editor Francisco Gordillo‐Vázquez outlines the potential of PECVD for new and emerging applications and introduces the papers in the issue that give a clear insight into low‐pressure PECVD research as it stands at the moment.
Novel use of the fluorescent dye 5‐(and‐6)‐chloromethyl SNARF‐1 acetate for the measurement of intracellular glutathione in leukemic cells and primary lymphocytes
Authors: Hamilton David , Loignon Martin , Alaoui‐Jamali Moulay A. , Batist Gerald 
Published: July 2007

AbstractGlutathione (GSH) plays an important role in protecting cells against injury, particularly during oxidative stress. Alterations in GSH metabolism are becoming the focus of attention in many diseases such as cancer, neurodegeneration, and AIDS. As such, a rapid assessment of GSH levels in a clinical setting is of increasing importance. We tested the efficacy of the thiol‐labeling fluorescent dye CM‐SNARF in its ability to measure variations in GSH concentration using a visible‐light flow cytometer. GSH levels in I83, Jurkat, and primary lymphocytes were depleted with buthionine sulfoximine (BSO) or diamide, or increased with N‐acetylcysteine (NAC). Following each treatment, cells were divided and either labeled with CM‐SNARF followed by flow cytometry analysis, or assayed for GSH using a biochemical method. BSO treatment caused a maximal 87–90% decrease in GSH and 68–76% decrease in fluorescence units. Diamide depleted GSH 91–95%, corresponding to a fluorescence decrease of 85–88%. NAC treatment increased GSH levels 27% and fluorescence 12–19%. The overall correlation (R2) between mean GSH concentration and mean fluorescence was 0.80–0.88. CM‐SNARF can be used to semi‐quantitatively and rapidly determine intracellular variations in GSH concentration in the range of 10–150 nmoles GSH/mg protein. © 2007 International Society for Analytical Cytology
Period‐doubling phenomena and chaos generated in the GaAs ring‐oscillator
Authors: Akamatsu Norio 
Published: July 2007

AbstractGaAs MESFET has the Schottky gate structure, in contrast to Si MOSFET. Consequently, the gate current increases rapidly when the gate voltage exceeds the Schottky voltage. In the direct‐coupled FET logic circuit (DCFL) using GaAs, when the input voltage is increased, a minimum is produced in the input‐output transfer characteristic in the low‐output voltage region. Because of this property, when a ring‐oscillator is constructed by cascading DCFL, a perioddoubling phenomenon is produced, generating a long‐period or irregular chaotic oscillation. This paper discusses these phenomena. the limiting set is determined by iteratively applying Poincaré mapping to the inputoutput characteristic. the stability is discussed using the Lyapunov exponent. It is shown as a conclusion that the number of invertor stages composing the GaAs ring oscillator should be as large a prime number as possible, as long as the oscillating condition is satisfied.
Abnormal signal detection and cancellation by using adaptive digital filter
Authors: Matsui Minoru , Hagiwara Masafumi , Nakagawa Masao , Hayashi Yasuhito 
Published: July 2007

AbstractRecently, the detection of a noise component added in a transmission line and a signal component buried in a noise have become important problems. an adaptive predictor using an adaptive digital filter (ADF) is effective in cancelling the noise component in the input signal, especially when the statistical property of the noise is unknown. In addition, it can operate at high speed because of its simplicity. the conventional adaptive predictor using ADF can detect the existence of an abnormal signal. However, it cannot detect its accurate waveform because of an occurrence of echo caused by the abnormal signal. Therefore, the conventional system cannot cancel the abnormal signal.In this paper, a novel system is proposed to cancel an abnormal signal in an input signal by using an adaptive predictor with a decision feedback. First, the cause of the occurrence of echo in the conventional predictor is shown. Next, the behavior of the new system is explained. Then a more accurate canceller of the abnormal signal with the two cascade‐connected ADFs is shown.
Uniform filter bank containing N‐path digital filter
Authors: Ikehara Masaaki , Takahashi Shinichi 
Published: July 2007

AbstractThis paper presents a construction method of a uniform filter bank using anN‐ path digital network. This filter bank is constructed by connecting anN‐path digital network to DFT polyphase filter banks. First, the input signal is divided into two parts by anN‐path digital network and its complement. These resulting output signals are separately band‐split and synthesized by DFT polyphase filter banks. Hence, its design method becomes very simple and both the required order and the number of multi plications can be reduced. Also, there quired structure is not so complicated.Further, a design method of the low‐ pass digital filter using this digital filter bank is presented. the low‐pass filter with cutoff near π/2 which cannot be obtained easily in the usual multirate digital filter, can be realized by using these filter banks.
A method to reduce the circuit scale for systolic arrays and its application to reed‐solomon codecs
Authors: Iwamura Keiichi , Imai Hideki , Dohi Yasunori 
Published: July 2007

AbstractThe systolic array is a scheme for parallel processing and provides an architecture which is suited to a high‐speed operation. Consequently, the systolic array has been applied to the system for which the high‐speed processing is required, but not to the system for which the reduction of the circuit scale is required. This paper demonstrates that the principle of the systolic array can be applied as a means of reducing the circuit scale. By the proposed method, the circuit scale can be reduced in the system based on the systolic array, without an appreciable modification of the connection in the array and the control. This paper discusses the Reed‐Solomon (RS) coder‐decoder based on the systolic array as an example, and shows that the circuit scale can be reduced simply. By this system, the RS coder‐decoder can be realized in a simple way by the small circuit scale, corresponding to the processing speed of the system.
Ordering properties for multiple‐choice questionnaire items
Authors: Takeya Makoto 
Published: July 2007

AbstractThe multiple‐choice questionnaire is used frequently in psychological investigations of human behavior. Previously the author has proposed SS (semantic structure) analysis. The method is based on the order of the questionnaire items, and the structurization of the items is considered using the asymmetrical measure called ordering coefficient, which is a quantitative representation of the order of the items. The multiple‐choice questionnaire can roughly be divided into the following three kinds: (1) Type I data, which are evaluation measure data where the score is high when the evaluation is high; (2) Type II data, which are evaluation measure data where the score is the highest at the central value of the evaluation and lower at both sides; (3) Type III data, which are a nominal measure data where the score does not have a particular meaning. Semantic structure analysis which was reported previously, is concerned with Type I data. With that method as the background, this paper newly proposes the ordering coefficient, which can be applied also to Type II and Type III data. Then the effective category number is proposed as an index representing the statistical property of the answer distribution. It is shown that the sequence reference of the ordered structure based on the ordering coefficient is the second‐order moment around the central value in Type II data, and is the effective category number in Type III data. Finally, the usefulness of the structurization methods is investigated and possible applications are discussed.
Relationship between acceleration factor of weibull‐type lifetime distribution and proportional hazard model
Authors: Shiomi Hiroshi 
Published: July 2007

AbstractBased on the knowledge concerning the life test for Weibull distribution, this paper considers the regression model for the reliability proposed by Cox et al., especially the proportional hazard model assuming Weibull distribution. Also discussed are the properties of the functiongterm representing the effect of factorxother than timet.First, the relation between the regression expression for thegterm and the reaction rate model is presented. It is shown that thegterm corresponds to the failure rate acceleration factor in the accelerated life test, and is related directly to the lifetime acceleration factor as well as other acceleration factors for the reliability parameters.An analogy is made between the expression that the reliability at the reference state to the power ofgis equal to the reliability in the accelerated state, and the weakest link model forglinks. Based on that analogy, it is shown that the reliability in the accelerated state is equivalent to the reliability of the series structure ofgindependent components with the reliability at the reference state. Thus,gcan be integrated as an acceleration factor representing a kind of scaling effect. It is shown also thatgcan be considered in the high‐reliability range as a reduction factor for the number of samples required to ensure reliability.
A study on finite wordlength effects in FIR digital echo cancellers using learning identification algorithm
Authors: Yasukawa Hiroshi , Ara Youjirou 
Published: July 2007

AbstractFinite wordlength effects on the steady‐state characteristics of finite impulse response adaptive digital echo cancellers are considered. Focusing on an FIR‐type echo canceller based on the learning identification algorithm, the so‐called normalized least mean square algorithm was investigated. Both fixed point and floating point arithmetic systems are discussed. The equivalent noise models for both systems are given, and the output errors caused by quantization and rounding noises were analyzed to allow explicit representation of echo canceller parameters (particularly wordlength) when the input signal is white Gaussian.Further, the relationship between echo cancellation and circuit parameters such as number of filter tap, loop‐gain coefficient, etc., the optimal parameter values to minimize output error are also discussed. Computer simulation results were compared with the analytical values and found to be in good agreement. The proposed method is valid for obtaining the performance of echo cancellers.
Evaluation of the smoothed group delay spectrum distance measure for speaker‐dependent speech recognition
Authors: Umezaki Taizo , Itakura Fumitada 
Published: July 2007

AbstractThis paper evaluates first the smoothed group delay spectrum (SGDS) distance measure through the isolated work speech recognition experiment by specified speakers. The experiment was performed for the following three cases, considering the speech recognition in the actual environment: 1) the case where the channels have difference characteristics; 2) the case where a white noise is added to the input speech; and 3) the case where the telephone speech is used as the input.In all three cases, the recognition rate is improved drastically compared to the traditional LPC cepstrum distance measure. An improvement of the recognition rate by 16 percent was realized under the noise of segmental SN ratio 20 dB. Then the distance measure is evaluated for the case where the FFT cepstrum is converted into the group delay spectrum.The proposed method gives a better recognition rate compared to the conventional FFT cepstrum distance measure, but the result is worse than the SGDA measure by approximately 3 percent since the higher‐order FFT cepstrum coefficient has a larger variance on the time axis.Finally, the SGDS distance measure is evaluated by the isolated word speech recognition system with the monosyllable as the registered speech. The vowel recognition rate is improved, which improved the recognition rates for the syllable and the word by 2 percent or more on a relative scale.
Trapped‐energy piezoelectric resonators with elliptical ring electrodes
Authors: Nakamura Kiyoshi , Yasuike Ryoichi , Shimizu Hiroshi 
Published: July 2007

AbstractThis paper proposes and investigates the characteristics of trapped‐energy piezoelectric resonators with elliptical ring electrodes conforming to anisotropies in the piezoelectric substrate. In such piezoelectric resonators, the electrode area can be enlarged without changing its single resonance characteristics. Therefore, the resonator has a low equivalent resistance. Moreover, to check the suitability of the elliptical ring electrodes for the proposed application, some resonators were fabricated using ceramic and AT‐cut quartz plates.It is shown that lower equivalent resistance is obtained in this case compared to the conventional circular electrode resonators. Also, through the experiment it is shown that by allowing a few anharmonic overtones to appear, an AT‐cut quartz 3rd‐overtone resonator with a low equivalent resistance of ten‐odd Ohms can be realized.
A complex digital filter with asymmetrical frequency response based on imaginary resistance
Authors: Takahashi Akira , Nagai Nobuo , Miki Nobuhiro 
Published: July 2007

AbstractA new frequency transformation is introduced by incorporating imaginary resistances into transmission line filters. Asymmetrical complex bandpass responses are derived from real low‐pass prototypes while the magnitude ripples are unchanged. The transformation is applied to designs of IIR digital filters with different inclinations on the upper and the lower transition band. The overall design is completed without iteration. As for a low‐pass to bandpass transformation based on a real function, the inclinations of the transition bands depend to the passband allocation. Crystal et al. [1] considered a simple shifting transformation to derive complex digital filters and Belevitch [4] examined a similar method for lumped constant networks. The upper and the lower transition band of such a filter become tunable but they are restricted to be symmetrical. By contrast, the proposed method enables highly flexible specifications. A design example is shown.
Output roundoff error in block realization of state‐space digital filters
Authors: Oguro Yoshinari , Yoshikawa Toshinori 
Published: July 2007

AbstractThis paper presents the analysis of the roundoff error due to product quantization for the block state‐space digital filter implemented with a digital signal processor (DSP) or a special‐purpose LSI for filtering in one dimension (1‐D) and two dimension (2‐D). Here, it is assumed that a special‐purpose LSI for filtering has two wordlengths, that is: 1) the external wordlength for the input signals, the output signals, the filter coefficients, and the state variables; and 2) the internal word‐length for the arithmetic logic unit (ALU) in that LSI. It is assumed also that the internal wordlength is longer than the external one.Two numerical examples are illustrated for a 2‐D second‐order filter and a 2‐D (3, 3)‐th‐order filter. The results act as a guide to determine the internal word‐length and the external wordlength of a special‐purpose LSI. Moreover, by setting the internal wordlength a few bits longer than the external wordlength, the roundoff error of block filtering can be reduced to from 20 through 60 percent compared with the nonblock filtering.
M/G/1system with set‐up time for server replacement
Authors: Nishigaya Takashi , Mukumoto Kaiji , Fukuda Akira 
Published: July 2007

AbstractThis paper proposes anM/G/1queueing model in which the server is replaced by another one with different service time distribution when the number of customers in the system exceeds a threshold value.A random set‐up time is needed to introduce the second server. This server works until the system becomes empty. This kind of system will appear, for instance, when the server is changed to a faster one as the number of waiting customers becomes too great.In data communication systems, the set‐up time may correspond to the time until the new carrier frequency for the faster transmission speed becomes stable, the time needed to assign a new link and/or the time necessary to inform a partner of a change in line speed.The behavior of the customers who receive the first and second kinds of service is analyzed using the theory of finite Markov chain and the decomposition property of theM/G/1system with server vacations, respectively. Important performance measures, such as the distribution and average of the number of customers in the system and their average time in the system, are obtained. The influence of server characteristics, the conditions under which the server is replaced, and the distribution of set‐up time on the performance of the system are clarified.
Image processing by two‐dimensional recursive filters using the fornasini‐marchesini model
Authors: Hinamoto Takao , Muneyasu Mitsuji 
Published: July 2007

AbstractThis paper considers a simple two‐dimensional (2‐D) IIR filter based on the Fornasini‐Marchesini local state‐space (LSS) model. It is shown that if image processing is carried out using such filters from four directions, smoothing, edge detection or edge enhancement can be achieved without any distortion. The proposed technique allows one to flexibly perform the forementioned filtering by choosing three parameters. Moreover, filter analysis including stability is easy due to using a well‐known 2‐D LSS model. Finally, some examples are given to illustrate the utility of the proposed technique.