bluuebunny/crossref_metadata_2025 huggingface dataset:
Linkage disequilibrium pattern of the ATM gene in breast cancer patients and controls; association of SNPs and haplotypes to radio-sensitivity and post-lumpectomy local recurrence
Authors: Edvardsen Hege , Tefre Toril , Jansen Laila , Vu Phuong , Haffty Bruce G , Fosså Sophie D , Kristensen Vessela N , Børresen-Dale Anne-Lise
Published: July 2007

Background

The ATM protein is activated as a result of ionizing radiation, and genetic variants of the ATM gene may therefore affect the level of radiation-induced damage. Individuals heterozygous for ATM mutations have been reported to have an increased risk of malignancy, especially breast cancer.

Materials and methods

Norwegian breast cancer patients (272) treated with radiation (252 of which were evaluated for radiation-induced adverse side effects), 95 Norwegian women with no known history of cancer and 95 American breast cancer patients treated with radiation (44 of which developed ipsilateral breast tumour recurrence, IBTR) were screened for sequence variations in all exons of the ATM gene as well as known intronic variants by denaturating high performance liquid chromatography (dHPLC) followed by sequencing to determine the nature of the variant.

Results and Conclusion

A total of 56 variants were identified in the three materials combined. A borderline significant association with breast cancer risk was found for the 1229 T>C (Val>Ala) substitution in exon 11 (P-value 0.055) between the Norwegian controls and breast cancer patients as well as a borderline significant difference in haplotype distribution (P-value 0.06). Adverse side effects, such as: development of costal fractures and telangiectasias, subcutaneous and lung fibrosis, pleural thickening and atrophy were evaluated in the Norwegian patients. Significant associations were found for several of the identified variants such as rs1800058 (Leu > Phe) where a decrease in minor allele frequency was found with increasing level of adverse side effects for the clinical end-points pleural thickening and lung fibrosis, thus giving a protective effect. Overall our results indicate a role for variation in the ATM gene both for risk of developing breast cancer, and in radiation induced adverse side effects. No association could be found between risk of developing ipsilateral breast tumour recurrence and any of the sequence variants found in the American patient material.
Tight glycaemic control: a prospective observational study of a computerised decision-supported intensive insulin therapy protocol
Authors: Shulman Rob , Finney Simon J , O'Sullivan Caoimhe , Glynne Paul A , Greene Russell
Published: July 2007

Introduction

A single centre has reported that implementation of an intensive insulin protocol, aiming for tight glycaemic control (blood glucose 4.4 to 6.1 mmol/l), resulted in significant reduction in mortality in longer stay medical and surgical critically ill patients. Our aim was to determine the degree to which tight glycaemic control can be maintained using an intensive insulin therapy protocol with computerized decision support and to identify factors that may be associated with the degree of control.

Methods

At a general adult 22-bed intensive care unit, we implemented an intensive insulin therapy protocol in mechanically ventilated patients, aiming for a target glucose range of 4.4 to 6.1 mmol/l. The protocol was integrated into the computerized information management system by way of a decision support program. The time spent in each predefined blood glucose band was estimated, assuming a linear trend between measurements.

Results

Fifty consecutive patients were investigated, involving analysis of 7,209 blood glucose samples, over 9,214 hours. The target tight glycaemic control band (4.4 to 6.1 mmol/l) was achieved for a median of 23.1% of the time that patients were receiving intensive insulin therapy. Nearly half of the time (median 48.5%), blood glucose was within the band 6.2 to 7.99 mmol/l. Univariate analysis revealed that body mass index (BMI), Acute Physiology and Chronic Health Evaluation (APACHE) II score and previous diabetes each explained approximately 10% of the variability in tight glycaemic control. BMI and APACHE II score explained most (27%) of the variability in tight glycaemic control in the multivariate analysis, after adjusting for age and previous diabetes.

Conclusion

Use of the computerized decision supported intensive insulin therapy protocol did result in achievement of tight glycaemic control for a substantial percentage of each patient's stay, although it did deliver 'normoglycaemia' (4.4 to about 8 mmol/l) for nearly 75% of the time. Tight glycaemic control was difficult to achieve in critically ill patients using this protocol. More sophisticated methods such as continuous blood glucose monitoring with automated insulin and glucose infusion adjustment may be a more effective way to achieve tight glycaemic control. Glycaemia in patients with high BMI and APACHE II scores may be more difficult to control using intensive insulin therapy protocols. Trial registration number 05/Q0505/1.
Extensive genomic diversity and selective conservation of virulence-determinants in enterohemorrhagic Escherichia colistrains of O157 and non-O157 serotypes
Authors: Ogura Yoshitoshi , Ooka Tadasuke , Asadulghani  , Terajima Jun , Nougayrède Jean-Philippe , Kurokawa Ken , Tashiro Kousuke , Tobe Toru , Nakayama Keisuke , Kuhara Satoru , Oswald Eric , Watanabe Haruo , Hayashi Tetsuya
Published: July 2007

Background

Enterohemorrhagic Escherichia coli (EHEC) O157 causes severe food-borne illness in humans. The chromosome of O157 consists of 4.1 Mb backbone sequences shared by benign E. coli K-12, and 1.4 Mb O157-specific sequences encoding many virulence determinants, such as Shiga toxin genes (stx genes) and the locus of enterocyte effacement (LEE). Non-O157 EHECs belonging to distinct clonal lineages from O157 also cause similar illness in humans. According to the 'parallel' evolution model, they have independently acquired the major virulence determinants, the stx genes and LEE. However, the genomic differences between O157 and non-O157 EHECs have not yet been systematically analyzed.

Results

Using microarray and whole genome PCR scanning analyses, we performed a whole genome comparison of 20 EHEC strains of O26, O111, and O103 serotypes with O157. In non-O157 EHEC strains, although genome sizes were similar with or rather larger than O157 and the backbone regions were well conserved, O157-specific regions were very poorly conserved. Around only 20% of the O157-specific genes were fully conserved in each non-O157 serotype. However, the non-O157 EHECs contained a significant number of virulence genes that are found on prophages and plasmids in O157, and also multiple prophages similar to, but significantly divergent from, those in O157.

Conclusion

Although O157 and non-O157 EHECs have independently acquired a huge amount of serotype- or strain-specific genes by lateral gene transfer, they share an unexpectedly large number of virulence genes. Independent infections of similar but distinct bacteriophages carrying these virulence determinants are deeply involved in the evolution of O157 and non-O157 EHECs.
Diet of European mink (Mustela lutreola) in Northern Spain
Authors: Palazón Santiago , Ruiz-Olmo J. , Gosàlbez J.
Published: July 2007

This study describes the diet of European mink (Mustela lutreola) in Northern
Spain. The diet was analysed from 105 European mink samples. Moreover,
we collected other 37 faeces from a radiotracked European mink male. The
European mink diet was based on small mammals (relative frequency of
occurrences 36,9%), fish (30,6%) and birds (17,8%). The Levins index of
trophic-niche width was 3,76. Wood mouse Apodemus sylvaticus was the most
consumed small mammal and Cyprinids -mainly Barbus sp. was the most
consumed fish. The average size and weight of consumed fish were 13,5 cm
and 31,5 g, respectively and males consumed larger and heavier fish than
females.
Muridae (Rodentia) from the Khammouan Limestone and Xe Piane National Biodiversity Conservation Areas, Lao PDR
Authors: Smith Angela L. , Robinson Mark F. , Webber Maurice
Published: July 2007

This note details the murid specimens collected in 1997, 1998 and 1999 as the result of surveys of 3 sites in Xe Piane and of 11 sites in Khammouan Limestone NBCA, Lao PDR. Cranial and mandibular remains were obtained from raptor pellets collected from caves, hunters and carnivore droppings. Remains of 287 individuals of 13 species of Muridae were identified; three species from Xe Piane NBCA and 13 species from Khammouan Limestone NBCA. Two speciesMus shortridgeiandRattus argentiventerhad not previously been recorded from Lao PDR. Remains attributable to two additional genera were also found.
Development of tusks and associated structures inMesoplodonbidens (Cetaceae, Mammalia)
Authors: Macleod Colin D. , Herman Jerry S.
Published: July 2007

This study examined the development of the tusks and associated skeletal structures in a series of 18 specimens of Sowerby’s beaked whale (Mesoplodon bidens) from Scotland. The relative position of the tusks along the length of the mandible was found to move from 23% of mandible length from the anterior extremity in the smallest animal to around 37% in adults, due to a lengthening of the symphyseal region. A previously undescribed sexual dimorphism was noted, a bony abutment, or ossicular dental support, situated directly posterior to the erupted tusks of adult males. Ontogenetic changes associated with male maturity include an increase in tusk length, an increase in the length of the alveolus, a high level of wear on tusks, an increase in the depth of the mandible posterior to the alveolus, an increased level of mesorostral ossification and an overall thickening of the rostrum and the symphyseal region of the mandible. The tusks are presumed to be used in intraspecific aggressive interactions and the ossicular dental support may counteract backward and outward forces on them as they cut through an opponents flesh, while the thickening of the rostrum and mandible may reduce the risk of damage when the two animals make contact.
Testing the Non‐Unity of Rate Ratio under Inverse Sampling
Authors: Tang Man‐Lai , Liao Yi Jie , Ng Hong Keung Tony , Chan Ping Shing
Published: July 2007

Inverse sampling is considered to be a more appropriate sampling scheme than the usual binomial sampling scheme when subjects arrive sequentially, when the underlying response of interest is acute, and when maximum likelihood estimators of some epidemiologic indices are undefined. In this article, we study various statistics for testing non‐unity rate ratios in case‐control studies under inverse sampling. These include the Wald, unconditional score, likelihood ratio and conditional score statistics. Three methods (the asymptotic, conditional exact, and Mid‐P methods) are adopted for P ‐value calculation. We evaluate the performance of different combinations of test statistics and P ‐value calculation methods in terms of their empirical sizes and powers via Monte Carlo simulation. In general, asymptotic score and conditional score tests are preferable for their actual type I error rates are well controlled around the pre‐chosen nominal level, and their powers are comparatively the largest. The exact version of Wald test is recommended if one wants to control the actual type I error rate at or below the pre‐chosen nominal level. If larger power is expected and fluctuation of sizes around the pre‐chosen nominal level are allowed, then the Mid‐P version of Wald test is a desirable alternative. We illustrate the methodologies with a real example from a heart disease study. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Partial Oxidation of 4‐tert‐Butyltoluene Catalyzed by Homogeneous Cobalt and Cerium Acetate Catalysts in the Br−/H2O2/Acetic Acid System: Insights into Selectivity and Mechanism
Authors: van de Water Leon G. A. , Kaza Arati , Beattie James K. , Masters Anthony F. , Maschmeyer Thomas
Published: July 2007

The partial oxidation of 4‐tert‐butyltoluene to 4‐tert‐butylbenzaldehyde by hydrogen peroxide in glacial acetic acid, catalyzed by bromide ions in combination with cobalt(II) acetate or cerium(III) acetate, has been studied in detail. Based on the observed differences in reaction rates and product distributions for the different catalysts, a reaction mechanism involving two independent pathways is proposed. After the initial formation of a benzylic radical species, either oxidation of this intermediate by the metal catalyst or reaction with bromine generated in situ occurs, depending on which catalyst is used. The first pathway leads to the exclusive formation of 4‐tert‐butylbenzaldehyde, whereas reaction of the radical intermediate with bromine leads to formation of the observed side products 4‐tert‐butylbenzyl bromide and its hydrolysis and solvolysis products 4‐tert‐butylbenzyl alcohol and 4‐tert‐butylbenzyl acetate, respectively. The cobalt(II) catalysts Co(OAc)2 and Co(acac)2 are able to quickly oxidize the radical intermediate, thereby largely preventing the bromination reaction (i.e., side‐product formation) from occurring, and yield the aldehyde product with 75–80 % selectivity. In contrast, the cerium catalyst studied here exhibits an aldehyde selectivity of around 50 % due to the competing bromination reaction. Addition of extra hydrogen peroxide leads to an increased product yield of 72 % (cerium(III) acetate) or 58 % (cobalt(II) acetate). Product inhibition and the presence of increasing amounts of water in the reaction mixture do not play a role in the observed low incremental yields.
Overcoming the Demons of Protecting Groups with Amphoteric Molecules
Authors: Yudin Andrei K. , Hili Ryan
Published: July 2007

Synthetic organic chemists have long depended on protecting group manipulations when faced with the challenges of chemoselectivity and functional group incompatibility. Overcoming this dependence will improve the overall efficiency of chemical synthesis. By taking advantage of orthogonally reactive functional groups, amphoteric molecules can afford access not only to more efficient and strategic syntheses but also to the development of novel chemical transformations.
X‐ray Structures and Thermodynamics of the Interaction of PA‐IIL from Pseudomonas aeruginosa with Disaccharide Derivatives
Authors: Marotte Karine , Sabin Charles , Préville Cathy , Moumé‐Pymbock Myriam , Wimmerová Michaela , Mitchell Edward P. , Imberty Anne , Roy René
Published: July 2007

Pseudomonas aeruginosa is an opportunistic bacterium showing increasing resistance to antibiotics and consequently represents elevated threatening problems in hospital environments, particularly for cystic fibrosis patients. The use of glycomimetics as an anti‐adhesive strategy against microorganisms may complement the use of antibiotics. PA‐IIL lectin (LecB) from P. aeruginosa constitutes an appealing target for antibacterial agents, as it has been proposed to play a key role in binding to airway epithelia and/or to be involved in biofilm formation. The lectin has an unusually high affinity for L‐fucose and related oligosaccharides. In the work presented herein, the disaccharide αFuc1‐4GlcNAc is used as a scaffold toward the synthesis of a series of glycomimetic derivatives. Microcalorimetry and structural studies indicate that several of the derivatives are potent inhibitors of the lectin, with affinity in the same range as the best known natural ligand, Lewis a, and could represent interesting leads for the development of future antibacterial compounds.
The impact of pre‐ and post‐transplantation positron emission tomography using 18‐fluorodeoxyglucose on poor‐prognosis lymphoma patients undergoing autologous stem cell transplantation
Authors: Filmont Jean‐Emmanuel , Gisselbrecht Christian , Cuenca Xavier , Deville Laure , Ertault Marjan , Brice Pauline , De Kerviler Eric , Briere Josette , Larghero Jérome , Moretti Jean‐Luc , Mounier Nicolas
Published: July 2007

BACKGROUND.

In patients with lymphoma who had a poor prognosis, pretransplantation 18‐fluorodeoxyglucose (FDG)‐positron‐emission tomography (PET) was important for the evaluation of response and outcome. However, little is known about the correlation of FDG‐PET with post‐transplantation PET. The current study was designed to ascertain whether positive pretransplantation PET images are modified by the conditioning regimen.

METHODS.

Sixty consecutive patients who had achieved remission and underwent consolidation by autologous stem cell transplantation (ASCT) had PET images obtained before ASCT (after 3 or 4 chemotherapy cycles) and 100 days after ASCT. The correlation was explored between the presence of abnormal 18‐FDG uptake (PET positive) or its absence (PET negative) and patient outcomes.

RESULTS.

Before ASCT, 31 patients achieved complete remission (CR), and 23 patients achieved uncertain CR. Before ASCT, 44 patients (75%) were had negative PET images; and, after ASCT, 48 patients (80%) had negative PET images. One year after ASCT, the estimated event‐free survival (EFS) rate was 80% in patients who had negative pre‐ASCT PET images compared with 43% in patients who had positive pre‐ASCT PET images (P = .0002). The EFS rate was 81% in patients who had negative post‐ASCT PET images compared with 25% in patients who had negative post‐ASCT PET images (P < .0001). In multivariate analysis, only the results for pre‐ and post‐ASCT PET images retained prognostic value, with relative risks of failure estimated at 4.9 and 11.9, respectively.

CONCLUSIONS.

A positive pre‐ASCT PET image indicated a high risk of ASCT failure, which was increased by a positive post‐ASCT PET image. For patients with lymphoma who have positive pre‐ASCT PET images, more investigations using new treatment approaches will be required. For patients who have negative pre‐ASCT PET images, obtaining post‐ASCT PET images does not seem to be mandatory. Cancer 2007. © 2007 American Cancer Society.
Numerical study of radiation effect on MHD transient mixed‐convection flow over a moving vertical cylinder with constant heat flux
Authors: Elgazery Nasser S. , Hassan M. A.
Published: July 2007

In this paper, a numerical analysis to study thermal radiation effect on magnetohydrodynamic (MHD) unsteady mixed‐convection flow over a moving vertical cylinder with constant heat flux through a porous medium in the presence of transversal uniform magnetic field has been performed. The boundary layer equations are transformed into a linear algebraic system by a Crank–Nicolson type of implicit finite‐difference method. The stability condition of the scheme was studied. Numerical results are presented with various sets of parameters for both air and water. The results show many interesting effects on velocity, temperature and concentration profiles on local as well as average shear stress, rate of heat and mass transfer. Also, the velocity and temperature profiles are compared with the available results in the literature and it is found to be in good agreement. Copyright © 2007 John Wiley &
Sons, Ltd.
Remedies to rotational frame dependence and interpolation failure of US‐QUAD8 element
Authors: Ooi E. T. , Rajendran S. , Yeo J. H.
Published: July 2007

It is known that the recently introduced unsymmetric 8‐node quadrilateral element (US‐QUAD8) is highly tolerant to mesh distortions. The high distortion tolerance of US‐QUAD8 is due to the ability of the element to satisfy all the desirable compatibility and completeness requirements of the test and trial functions. The element uses isoparametric and metric shape functions as the test and trial functions, respectively. Despite its high distortion tolerance, the element has two defects. The use of metric shape functions as trial functions causes the element to exhibit rotational frame dependence as well as interpolation failure under certain conditions. A detailed investigation into both these problems is reported and remedies are proposed. Copyright © 2007 John Wiley & Sons, Ltd.
From Carbon Nanostructures to New Photoluminescence Sources: An Overview of New Perspectives and Emerging Applications of Low‐Pressure PECVD
Authors: Gordillo‐Vázquez F. J. , Herrero V. J. , Tanarro I.
Published: July 2007

Low‐pressure, plasma‐enhanced (PE)CVD is a powerful and versatile technique that has been used for thin‐film deposition and surface treatment since the early 1960s. However, it is only recently that it has been used in applications other than the different stages of microelectronic circuit fabrication. Now, PECVD is being used in emerging applications due to new materials and process requirements in a wide variety of areas, such as biomedical applications, solar cells, fuel cell development, fusion research, or the synthesis of silicon nanocrystals showing efficient photoluminescence, useful for future solid‐state light sources. These new scenarios have stimulated further development of novel PECVD diagnostic techniques, together with fundamental experimental and theoretical studies aimed at a better understanding of some of the basic processes underlying the plasma/surface interaction. This paper gives an overview of some new research areas where PECVD is finding promising applications.
Plasma‐Enhanced Atomic Layer Deposition of Palladium on a Polymer Substrate
Authors: Ten Eyck G. A. , Pimanpang S. , Juneja J. S. , Bakhru H. , Lu T.‐M. , Wang G.‐C.
Published: July 2007

In this paper, a method for the plasma‐enhanced (PE) atomic layer deposition (ALD) of palladium on air‐exposed, annealed poly(p‐xylylene) (Parylene‐N, or PPX) is presented. Palladium is successfully deposited on PPX at 80 °C using a remote, inductively coupled, hydrogen/nitrogen plasma with palladium (II) hexafluoroacetylacetonate (PdII(hfac)2) as the precursor. By optimizing the mixture of hydrogen and nitrogen, the polymer surface is modified to introduce active sites allowing the chemisorption of the PdII(hfac)2. In addition, enough free hydrogen atoms are available at the surface for ligand removal and Pd reduction, while at the same time, enough hydrogen atoms are consumed in the plasma to ensure there is no visible degradation of the PPX. X‐ray photoelectron spectroscopy (XPS) measurements of the substrate after hydrogen/nitrogen plasma treatment at 50 W clearly show the presence of nitrogen bound to the substrate surface. XPS measurements of the deposited Pd films indicate good quality for both substrates, suggesting that the substrate temperature was low enough to prevent dissociation of the hfac ligand and adequate scavenging of the hfac ligand by the available atomic hydrogen. The remote hydrogen/nitrogen plasma enables Pd film deposition on polymer surfaces, which do not typically react with the Pd precursor, and are not catalysts for the dissociation of molecular hydrogen.
On the Mechanism of Nitrogenated Carbon Film Deposition by PACVD in the Presence of Nitrogen. A Cryo‐Trapping Assisted Mass Spectrometric Study
Authors: Tabarés F. L. , Tafalla D. , Ferreira J. A.
Published: July 2007

The well‐documented effect of film inhibition/perturbation that nitrogen molecules have in the plasma‐assisted (PA)CVD of a‐C/N:H films in a DC glow discharge reactor under low pressure is investigated. Plasma parameters, gas‐phase composition, and film characteristics are recorded using several diagnostic techniques, including the newly developed cryo‐trapping assisted mass spectrometry (CTAMS). Five gas mixtures are investigated; CH4/H2, CH4/N2/H2, and CH4/Ar/H2 as precursors for the films, at low relative concentration of the hydrocarbon molecule (methane), and H2/N2 and He/N2 as film etchers. There are found to be strong differences in the composition of reaction product between systems in which plasma/surface interactions are dominated by ion‐induced processes (sputtering), and those where chemical reactions with nitrogenated species would behave as scavengers of the film precursor. The implications of these findings for the proposed mechanisms of a‐C/N:H film growth are addressed. The application of the scavenger technique for the inhibition of tritium‐containing carbon co‐deposits in the divertor region of fusion reactors, as an international thermonuclear experimental reactor (ITER) in the carbon‐dominated scenarios, is analyzed in the light of these findings.
Notes on q‐ary expanded Reed‐Solomon codes over GF(qm)
Authors: Sakakibara Katsumi , Tokiwa Kin‐Ichiroh , Kasahara Masao
Published: July 2007

Error‐correcting techniques are important in digital communications, for example, satellite communications, mobile communications, and digital audio systems. In digital communications, block codes such as Reed‐Solomon (RS) codes (recommended for compact disc (CD) and digital audio tape (DAT)) are used.

This paper treats q‐ary expanded RS codes over GF(qm) as two‐dimensional codes over GF(q) and gives a new interpretation to q‐ary codes by utilizing the concept of superimposed concatenated codes. Using this new interpretation a lower bound on the minimum distance of q‐ary expanded RS codes over GF(qm) is derived and a new decoding algorithm is clarified.
Upper bounds for the fg‐chromatic index of graphs
Authors: Nakano Shin‐Ichi , Nishizeki Takao , Saito Nobuji
Published: July 2007

This paper introduces a new edge‐coloring of graphs called “fg‐edge‐coloring.” It is used to color all edges of a graph so that at most f(v) edges of a same color exist among edges incident at each vertex v, and at most g(vw) edges among multiple edges joining each pair of vertices v and w. Various upper bounds are given for the fg‐chromatic index, that is, the minimum number of colors required for fg‐coloring. One of them is a generalization of the upper bounds for the ordinary edge‐coloring by Vizing and Hakimi‐Kariv. the proof is constructive and yields a polynomial time algorithm to determine fg‐coloring using colors no more than the upper bound.
An algorithm to enumerate all rectangular dual graphs
Authors: Tani Katsunori , Shirakawa Isao , Tsukiyama Shuji
Published: July 2007

Due to the recent development of VLSI technology, circuits have begun to be made on LSI chips in every field of industry. In the layout design, one of the LSI design processes, the main objective, is to minimize the chip area to increase the efficiency and yield rate of ICs. Thus, it is important to find a good floor plan in the sense of area efficiency.

This paper considers the problem of enumerating all rectangular dual graphs which are useful in floor plan design of VLSI using the notion of rectangular dual graph. We present an efficient algorithm which runs in O(|V|2) per one rectangular dual graph to be enumerated for a given maximal planar graph G0, where V is a vertex set of G0.
A generalized sampling theorem
Authors: Ogawa Hidemitsu
Published: July 2007

Using the theory of pseudo‐biorthogonal base and the notion of reproducing kernel, we derive a very broad generalized sampling theorem with real pulse. In addition, it includes the traditional sampling theorem with ideal pulse as its special case. It also includes all the sampling theorems in the cases of bandpass‐type band‐limited signal space for nonuniformly spaced sampling points, for many variables, and for the case in which the notion of frequency is extended from Fourier transform to general integral transform. This generalized sampling theorem is effective also for so‐called undersampling whereby there are too few sampling points compared with the dimension of signal space, and for so‐called oversampling due to too many sampling points. Moreover, it is effective in the case where both occur; that is, in the case where it is undersampling from the standpoint of signal space while it is oversampling in a space of restored signal. For undersampling, the generalized sampling theorem provides the best approximation for each original signal.
An NIC‐improved balanced integrator and its application to filters
Authors: Takagi Shigetaka , Anzai Takashi , Yanagisawa Takeshi
Published: July 2007

The authors have proposed a high‐frequency monolithic integrator in [1]. In the proposed circuit, lateral pnp transistors with less satisfactory high‐frequency response were utilized and they limited the high‐frequency response of the integrator. the response was improved by a passive compensation. However, it is difficult to determine the capacitance for the passive compensation.

From such a viewpoint, this paper shows that an integrator with a balanced negative impedance converter can be constructed using only npn transistors. the computer analysis is made for the proposed integrator and the integrator proposed in [1], using SPICE 2G.1. It is shown that a performance better than that of the integrator in [1] is obtained without compensation owing to the elimination of pnp transistors. the proposed integrator was applied to the balanced third‐order low‐pass active RC filter system with a cutoff frequency of 1 MHz and with an automatically tunable function. an experiment was performed indicating the practical usefulness of the proposed integrator as well as the system.
A 2‐D digital filter design technique using separate approximation of phase and magnitude responses by denominator and numerator
Authors: Taguchi Akira , Nakahashi Tomoko , Hamada Nozomu
Published: July 2007

This paper discusses a design of two‐dimensional HR digital filter in the frequency domain, where the magnitude and the phase responses are assigned separately to the denominator and the numerator, respectively, and are designed independently. the design procedure is as follows. Considering only the phase, the all‐pole filter (denominator polynomial) is designed. Then the numerator is designed from the 2‐D mirror‐ image polynomial as a correction for the magnitude. In earlier methods of this kind, a nonlinear problem is encountered in the design of the all‐pole filter in approximating the phase. By contrast, in this paper, the 2‐D group‐delay (phase) approximation is reduced to the 2‐D spectral approximation by using the cepstrum, and the derivation of the parameters is reduced to the solution of the 2‐D normal equation. From the viewpoint of ensuring the stability, an approximation by three‐term separable all‐pole filter is also shown, which makes the stability test easy. an algorithm is shown which solves the ap proximation problem for this case by iteratively solving the linear problem. the proposed design method features smaller computational complexity, since the denominator and the numerator polynomials are derived independently. In addition, the design is made easy since the linear problems are handled throughout the filter design.
Determination of parameters of VHF quartz crystal units equipped with evaporated electrodes using an Fr‐meter fixture
Authors: Watanbe Yasuaki , Oomura Yoshimasa , Lizuka Yukinori
Published: July 2007

The Fr meter method is described as a method of measuring quartz crystal units in Appendix 1 of the Japanese Industrial Stand ard (JIS). When the resonance frequency and equivalent parameters of a quartz crystal unit are measured with the Fr‐meter fixture, an equivalent circuit based on four parameters has usually been employed. However, this equivalent circuit is not accurate for representing the impedance characteristic of the unit over a wide frequency range. to solve this problem, this paper offers an accurate method based on an equivalent circuit having five parameters for measuring the parameters over a wide range (from fs to fp) with the Fr meter fixture. the method is based on an equivalent circuit having five parameters.

This paper describes the principle of the method; measurements of VHF‐band quartz crystal units; comparisons of the results with those obtained by using the drop method; and an examination of the repeatability of the method. the results show that the standard deviation of the resonance frequencies is within 2 × 10‐8, and the frequency agrees well with that obtained by the drop method. the characteristics between frequency and impedance of quartz crystal units calculated by using the parameters obtained agree well with those measured. It was confirmed that the proposed method with the Fr‐meter fixture could accurately measure the resonance frequency and the parameters of quartz crystal units.
Method of designing SAW low‐pass filters
Authors: Fushimi Shigeo , Watanabe Takaya
Published: July 2007

Since it has been rather difficult to realize a relatively steep cutoff characteristic in a video band with switched‐capacitor filters and active ones, LC filters have been used for this purpose. This paper discusses surface acoustic wave (SAW) filters, and proposes a method of designing SAW low‐pass filters which were thought to be difficult to realize, the method offers an easy realization of low‐pass filters having a small size, excellent temperature characteristic, and linear phase characteristic. the low‐ pass filter is obtained by cutting a pair of electrodes having an equal length and an interval of quarter wavelength at a certain distance from the busbars so that electrically floating electrodes are formed without connecting any busbar. This paper describes the conditions required for coefficients of the FIR filter suitable for forming electrodes of an SAW filter, and the method of designing SAW low‐pass filters. A design example of an SAW filter consisting of unapodized electrode (five taps) and apodized electrodes (141 taps) is given. the electrode configuration of a prototype device using this design is shown together with its frequency characteristic.
All‐pole low‐pass digital filters with (2m‐ 1)‐th flat and r‐th equiripple group delay
Authors: Kato Kyoto , Takebe Tsuyoshi
Published: July 2007

As is well known, there are two kinds of constant delay all‐pole low‐pass digital filter functions: maximally flat type and equiripple type. In some cases of waveform transmission, transfer functions with inter mediate characteristics between the two forementioned types are preferable. This paper presents such transfer functions called (M‐r)FD function. In the n‐th order function, the delay flatness is reduced from the maximal order nO = (2n ‐ 1)‐th to (2m ‐ 1)‐th, where m < n. Then equiripple functions with a total of r maxima and minima of delay are derived utilizing the resulting r( = n – rn) degrees of freedom.

The derivation of the transfer function is based on the method by Fettweis, i.e., in other words, the function providing the max‐ finally flat delay is obtained by forming the continued‐fraction expansion of tanh of the constant delay and truncating its expression at the n‐th‐term. Among n coefficients α2 of the expression, r from the last are given small deviations. While maintaining the (2m‐1)‐th flatness at zero frequency, an approximation is made by the traditional Newton‐Raphson method so that the delay deviation from the constant exhibits an equiripple behavior with the width of ±Δτ the (M‐r)DF function was derived for the case where the delay at τ = 0 is specified and for the case where the constant delay band width is specified. Keeping constant, the bandwidth for constant delay in the derived characteristics is increased with the increase of the number of ripples. the derived functions are summarized in a table.
Roundoff noise analysis and optimal synthesis of two‐dimensional recursive digital filters based on the fomasini‐marchesini model
Authors: Hinarnoto Takao , Hamanaka Takashi , Maekawa Sadao
Published: July 2007

Based on the Fornasini‐Marchesini local state‐space model, a two‐dimensional round‐off‐noise analysis is carried out from which a new expression of the output‐noise variance is derived. an 12‐norm dynamic range scaling is also considered for the model. Then a general technique is developed for synthesizing the optimal model structure which minimizes the output‐noise power due to roundolf subject to a scaling constraint on the state variables. the synthesis utilizes a 2‐D similarity transformation matrix that is not block‐diagonal but general, and it requires solving only one optimization problem. Thus, the proposed synthesis is quite simple.
Finite element simulation for the design of an ultrasonic cleaning tank
Authors: Ando Ei'Ichi , Kagawa Yukio
Published: July 2007

This paper describes the application of the finite element method to simulation of an ultrasonic cleaning tank which consists of a liquid bath with vibrating plate walls. the vibration of a plate, from which the ultrasonic radiation takes place, is analyzed without loading, and it is shown that the location where the erosion occurs corresponds to the region of maximum stress in plate bending. Sound pressure distribution in the liquid bath, which is surrounded by the vibrating plate walls, is then considered as a two‐dimensional model in which the coupling between the plate vibration and the sound pressure in the liquid is taken into account. Some numerical demonstrations are made, which is compared with the measured results. the technique has again proved to be a useful means of solving problems of this kind.
Differential companding PCM by using optimum differential bit
Authors: Uchiyama Hiroki , Yamada Wasaku , Suzuki Masamitsu
Published: July 2007

Two speech coding methods combining dif ferential PCM (DPCM) with near instantaneous companding (NIC) are proposed in this paper. In general, if NIC is applied simply to DPCM, then the waveform cannot be reconstructed in the decoding process because of the bit removal during compression. to solve this problem, a method has been proposed which is based on the accumulation of the removed bits, but the companding ratio in this case is not sufficient for low bit rates.

In Method I proposed in this paper the compressed differential data obtained by NIC of the differential data are modified to minimize the error between the original data and the data decoded sequentially, sample by sample, for the given number of compressed bits. Method II is similar to Method I, but an optimum scale factor is chosen from three adjacent values. Thus, the error power is minimized over the block. Segmental SNR is used as a quality measure, and the results of the computer simulation show that higher speech quality is obtained than in the case of first‐order predictive ADPCM (ADPCMf).

The hardware realization of the proposed methods is extremely simple because both coding and decoding require merely additions and subtractions. This article presents the principle of the methods and the results of the simulation.
A method for designing IIR quadrature mirror filters
Authors: Takebe Tsuyoshi , Tsuji Toshiaki
Published: July 2007

In the subband coding system which is a low bit rate speed transmission one, a multirate quadrature mirror filter (QMF) bank is used by which voice signals are divided into two or more frequency bands and recombined. In this paper, a design method for two‐band analysis and synthesis IIR QMF is treated. For the phase characteristics being allowed to be nonlinear, the conditions to be satisfied by factors of the IIR QMF transfer function are known and, based on it, a design method of the transfer function by a successive approximation is known. the method in this paper does not use successive approximation. an analog filter with simultaneous Chebyshev characteristics in both the pass‐and stopbands is designed so that its squared magnitude response has an odd symmtry around its half‐magnitude point on the logarithmic frequency scale. Then it is bilinear transformed into a digital filter so that the analog half‐magnitude frequency is mapped onto the point with the digital frequency of w = π/2T. By combining this filter and the high‐pass filter obtained by shifting the former by w π/T, an exact QMF response can be obtained with analytical rigor. A design example is also presented.
Equivalent property between network analysis using virtual capacitors and steepest descent method
Authors: Asai Hideki
Published: July 2007

Global and stable numerical analysis algorithms of nonlinear network equations, which contain functions that are not monotonically increasing or whose differential coefficients vary broadly, include the homotopic method studied in nonlinear programming and the methods based on the insertion technique of virtual capacitors developed in Circuitsimulation. This paper shows first that these methods are almost essentially equivalent, and that the standard steepest descent method is equivalent to analyze state equations constructed by the insertion of virtual capacitors by implicit numerical integration. Moreover, a backward SD method is proposed based on the implicit use of the steepest descent method. Thic method is applied to linear and nonlinear systems, and its equivalency with the algorithms in the Circuitsimulators SRP and ASTAP using the concept of virtual capacitors is investigated. Finally, this method is applied to dc analysis, etc., of nonlinear resistive networks, and its effectiveness is verified by comparison with the results of analysis by the ASTAP method.
Generalized hyperplane methods for generating Λ‐extreme points and trade‐off rates for multiobjective optimization problem
Authors: Sakawa Masatoshi , Yano Hitoshi
Published: July 2007

The hyperplane method is a generalized scalarization technique for the traditional typical scalarization problem to determine the Pareto‐optimal solution for the multi‐objective optimization problem. This paper presents a generalized hyperplane method to determine the A‐extreme point, which is a generalization of the Pareto‐optimal solution. A situation is considered in which the decisionmaker specifies the A‐extreme points, and his or her preference is to be estimated.‐ It is shown that the trade‐off rate, which is considered as useful information, can be represented by a Lagrange multiplier obtained by solving the generalized hyperplane problem.
Design of three‐dimensional recursive digital filters with symmetry
Authors: Hinamoto Takao , Nakatsuji Akihiro , Maekawa Sadao
Published: July 2007

This paper discusses a useful design method for three‐dimensional recursive digital filters approximating the desired amplitude response with spherical or cubic symmetry and the constant group delay. the filter structure is chosen so that the denominator is of a separable form, composed of one‐dimensional polynomials of the same form, and the numerator is composed of a mirror‐ image three‐dimensional polynomial with 48‐ hedral symmetry. In the filter design, the denominator and the numerator approximate the phase and the amplitude responses, respectively, which are designed independently. the proposed method is advantageous since the required computation is relatively small and the numerator is determined by solving a linear equation. the stability of the filter is ensured by its structure.
A systematic method of synthesizing systolic arrays using a data dependence graph
Authors: Iiguni Youji , Sakai Hideaki , Tokumaru Hidekatsu
Published: July 2007

With the recent development of VLSI technology, the systolic array is considered as practically realizable, where a large number of processors are placed on a chip to perform a parallel computation. the systolic array is a dedicated VLSI, which has a hardware structure depending on the algorithm. Consequently, a problem is how to design the systolic array corresponding to the given algorithm. This paper proposes an automatic synthesis for the systolic array using the dependence vector representing the data dependence. It is noted first that the systolic array is determined by the vector along the projection direction and the vector along the computation direction of the data dependence graph. the constraint for the forementioned two vectors is derived for the systolic graph. the constraint for the forementioned two vectors is derived for the systolic array to be realizable. Then using the constraint, the systolic array is derived systematically. A feature of the proposed method is that more than one systolic array corresponding to an algorithm can be constructed without a duplication. the systolic array in which processors operate in different ways, can also be derived. Finally, the proposed method is applied to the matrix multiplication, convolution and LD decomposition, indicating its usefulness.
Bilateral constant‐resistance active variable attenuation equalizer
Authors: Takebe Tsuyoshi , Ogawa Keiji
Published: July 2007

Constant‐resistance active variable attentuation equalizers using a bridged T circuit are used for bilateral communication channel. Usually, the auxiliary circuits for a variable series branch impedance and a variable parallel branch impedance are constructured separately. For one variable parameter of the equalizer characteristics (such as one bump height for a bump type), one variable element is needed for series branch and the other is for parallel branch. This paper presents a method for realizing each variable impedance with a series connectio of a resistor and a variabel voltage‐controlled voltage source. From the circuit analysis, it is found that both variable voltages are always related via a constant ratio. Hence, if one of the voltage sources is constructed, the other is simply its constant multiple which results in simplification of the equalizer circuit. Finally, a switched capacitor implementatio of a bumpshaped variable attenuation equalizer is presented for illustration.
Design of narrow‐band FIR filters using interpolation technique
Authors: Hoshino Masanori , Ikehara Masaaki , Takahashi Shin‐Ichi
Published: July 2007

It is an important realization of digital filters to reduce the amount of hardware, notably multipliers. This paper proposes a cascade connection of IFIR (Interpolated FIR) filters by which a steep characteristic can be obtained with a small number of multipliers in most cases. the reduction of the multipliers is achieved by the determination of the transfer function of the overall cascade connection (not each element) by using the Lnorm approximation. This method also has an advantage in that its central frequency can be determined arbitrarily. the cascade connection of several elements reduces the degrading of its characteristic caused by the quantized coefficients as shown in examples, since the conditions required for each element are relaxed in this structure.
Quaternary cyclic an codes and Lee‐type modular arithmetic distance
Authors: Shimada Ryosaku , Watanabe Takashi , Tanaka Takeshi , Ohkura Yoshiteru
Published: July 2007

The arithmetic an codes are useful for error detection or error correction in both arithmetic operation and digital data transmission. Especially, the cyclic an codes based on an even‐radix number system are considered to be practical. This paper presents a fundamental theory of quaternary arithmetic distance and symmetric quaternary number system using five numerals, −2, −1, 0, 1, 2.

Following an introduction of the cyclic an codes, we describe a modular number system and some important properties of Lee‐type modular arithmetic distance. an elementary method to calculate the minimum distance of the codes is also provided.
Algorithms for finding internally disjoint paths in a planar graph
Authors: Suzuki Hitoshi , Akama Takehiro , Nishizeki Takao
Published: July 2007

Three efficient algorithms for finding vertex‐disjoint trees and internally disjoint paths in a planar graph are presented. Given a planar graph G and nets consisting of terminals lying on the external boundary, the first algorithm finds vertex‐disjoint trees, each of which interconnects all the terminals of a net. the second algorithm determines the maximum number k of internally disjoint paths between two specified vertices in the planar graph G. the third algorithm really finds these k paths. the time complexity of the first algorithm is O(n), those of the second and third are o(n log n). Here n is the number of vertices of the given graph G.