bluuebunny/crossref_metadata_2025 huggingface dataset:
The Small G Proteins of the Arf Family and Their Regulators
Authors: Gillingham Alison K. , Munro Sean
Published: July 2007

Small G proteins play a central role in the organization of the secretory and endocytic pathways. The majority of such small G proteins are members of the Rab family, which are anchored to the bilayer by C-terminal prenyl groups. However, the recruitment of some effectors, including vesicle coat proteins, is mediated by a second class of small G proteins that is unique in having an N-terminal amphipathic helix that becomes available for membrane insertion upon GTP binding. Sar1, Arf1, and Arf6 are the best-characterized members of this ADP-ribosylation factor (Arf) family. In addition, all eukaryotes contain additional distantly related G proteins, often called Arf like, or Arls. The complete Arf family in humans has 29 members. The roles of these related G proteins are poorly understood, but recent work has shown that some are involved in membrane traffic or organizing the cytoskeleton. Here we review what is known about all the members of the Arf family, along with the known regulatory molecules that convert them between GDP- and GTP-bound states.
Impact of Preoperative Anemia on Outcome in Patients Undergoing Coronary Artery Bypass Graft Surgery
Authors: Kulier Alexander , Levin Jack , Moser Rita , Rumpold-Seitlinger Gudrun , Tudor Iulia Cristina , Snyder-Ramos Stephanie A. , Moehnle Patrick , Mangano Dennis T.
Published: July 2007

Background—

The risk of preoperative anemia in patients undergoing heart surgery has not been described precisely. Specifically, the impact of low hemoglobin per se or combined with other risk factors on postoperative outcome is unknown. Thus, we determined the effects of low preoperative hemoglobin and comorbidities on postoperative adverse outcomes in patients with coronary artery bypass graft in a large comprehensive multicenter study.

Methods and Results—

The Multicenter Study of Perioperative Ischemia investigated 5065 patients with coronary artery bypass graft at 70 institutions worldwide, collecting ≈7500 data points per patient. In 4804 patients who received no preoperative transfusions, we determined the association between lowest preoperative hemoglobin levels and in-hospital cardiac and noncardiac morbidity and mortality and the impact of concomitant risk factors, assessed by EuroSCORE, on this effect. In patients with EuroSCORE <4 (n=2054), only noncardiac outcomes were increased, whereas patients with EuroSCORE ≥4 (n=2750) showed an increased incidence of all postoperative events, starting at hemoglobin <11 g/dL. Low preoperative hemoglobin was an independent predictor for noncardiac (renal>cerebral;
P
<0.001) outcomes, whereas the increase in cardiac events was due to other factors associated with preoperative anemia.

Conclusions—

Anemic patients undergoing cardiac surgery have an increased risk of postoperative adverse events. Importantly, the extent of preexisting comorbidities substantially affects perioperative anemia tolerance. Therefore, preoperative risk assessment and subsequent therapeutic strategies, such as blood transfusion, should take into account both the individual level of preoperative hemoglobin and the extent of concomitant risk factors.
Burden and Prognostic Importance of Subclinical Cardiovascular Disease in Overweight and Obese Individuals
Authors: Ingelsson Erik , Sullivan Lisa M. , Fox Caroline S. , Murabito Joanne M. , Benjamin Emelia J. , Polak Joseph F. , Meigs James B. , Keyes Michelle J. , O’Donnell Christopher J. , Wang Thomas J. , D’Agostino Ralph B. , Wolf Philip A. , Vasan Ramachandran S.
Published: July 2007

Background—

The burden and prognostic importance of subclinical cardiovascular disease (CVD) in obesity has not been investigated systematically.

Methods and Results—

We examined prevalence of subclinical disease in 1938 Framingham Study participants (mean age, 57 years; 59% women) by use of 5 tests (electrocardiography, echocardiography, carotid ultrasound, ankle-brachial pressure, and urinary albumin excretion) and stratified by body mass index (BMI) (normal, <25; overweight, 25 to <30.0; obese, ≥30 kg/m
2
) and waist circumference (WC) (increased, ≥88 cm for women or ≥102 cm for men). We investigated risk of overt CVD associated with adiposity according to presence versus absence of subclinical disease on any of the 5 tests. Prevalence of subclinical disease was higher in overweight (40.0%; adjusted odds ratio, 1.68) and obese individuals (49.7%; odds ratio, 2.82) compared with individuals with normal BMI (29.3%) and in individuals with increased WC (44.9%; odds ratio, 1.67) compared with normal WC (31.9%). On follow-up (mean 7.2 years), 139 participants had developed overt CVD. Presence of subclinical disease was associated with >2-fold risk of overt CVD in all BMI and WC strata, with no evidence of an interaction between BMI and subclinical disease. CVD risk was attenuated in participants with obesity or increased WC but without subclinical disease (adjusted hazard ratio for obesity, 1.57; 95% confidence interval, 0.74 to 3.33; adjusted hazard ratio for increased WC, 1.22; 95% confidence interval, 0.69 to 2.15), compared with individuals with normal BMI or WC and no subclinical disease, respectively.

Conclusions—

In our community-based sample, overweight and obesity were associated with high prevalence of subclinical disease, which partly contributed to the increased risk of overt CVD in these strata.
IL-13-induced proliferation of airway epithelial cells: mediation by intracellular growth factor mobilization and ADAM17
Authors: Booth Brian W , Sandifer Tracy , Martin Erika L , Martin Linda D
Published: July 2007

Background

The pleiotrophic cytokine interleukin (IL)-13 features prominently in allergic and inflammatory diseases. In allergic asthma, IL-13 is well established as an inducer of airway inflammation and tissue remodeling. We demonstrated previously that IL-13 induces release of transforming growth factor-α (TGFα) from human bronchial epithelial cells, with proliferation of these cells mediated by the autocrine/paracrine action of this growth factor. TGFα exists as an integral membrane protein and requires proteolytic processing to its mature form, with a disintegrin and metalloproteinase (ADAM)17 responsible for this processing in a variety of tissues.

Methods

In this study, normal human bronchial epithelial (NHBE) cells grown in air/liquid interface (ALI) culture were used to examine the mechanisms whereby IL-13 induces release of TGFα and cellular proliferation. Inhibitors and antisense RNA were used to examine the role of ADAM17 in these processes, while IL-13-induced changes in the intracellular expression of TGFα and ADAM17 were visualized by confocal microscopy.

Results

IL-13 was found to induce proliferation of NHBE cells, and release of TGFα, in an ADAM17-dependent manner; however, this IL-13-induced proliferation did not appear to result solely from ADAM17 activation. Rather, IL-13 induced a change in the location of TGFα expression from intracellular to apical regions of the NHBE cells. The apical region was also found to be a site of significant ADAM17 expression, even prior to IL-13 stimulation.

Conclusion

Results from this study indicate that ADAM17 mediates IL-13-induced proliferation and TGFα shedding in NHBE cells. Furthermore, they provide the first example wherein a cytokine (IL-13) induces a change in the intracellular expression pattern of a growth factor, apparently inducing redistribution of intracellular stores of TGFα to the apical region of NHBE cells where expression of ADAM17 is prominent. Thus, IL-13-induced, ADAM17-mediated release of TGFα, and subsequent epithelial cell proliferation, could contribute to the epithelial hypertrophy, as well as other features, associated with airway remodeling in allergic asthma.
Phenotype clustering of breast epithelial cells in confocal images based on nuclear protein distribution analysis
Authors: Long Fuhui , Peng Hanchuan , Sudar Damir , Lelièvre Sophie A , Knowles David W
Published: July 2007

Background

The distribution of chromatin-associated proteins plays a key role in directing nuclear function. Previously, we developed an image-based method to quantify the nuclear distributions of proteins and showed that these distributions depended on the phenotype of human mammary epithelial cells. Here we describe a method that creates a hierarchical tree of the given cell phenotypes and calculates the statistical significance between them, based on the clustering analysis of nuclear protein distributions.

Results

Nuclear distributions of nuclear mitotic apparatus protein were previously obtained for non-neoplastic S1 and malignant T4-2 human mammary epithelial cells cultured for up to 12 days. Cell phenotype was defined as S1 or T4-2 and the number of days in cultured. A probabilistic ensemble approach was used to define a set of consensus clusters from the results of multiple traditional cluster analysis techniques applied to the nuclear distribution data. Cluster histograms were constructed to show how cells in any one phenotype were distributed across the consensus clusters. Grouping various phenotypes allowed us to build phenotype trees and calculate the statistical difference between each group. The results showed that non-neoplastic S1 cells could be distinguished from malignant T4-2 cells with 94.19% accuracy; that proliferating S1 cells could be distinguished from differentiated S1 cells with 92.86% accuracy; and showed no significant difference between the various phenotypes of T4-2 cells corresponding to increasing tumor sizes.

Conclusion

This work presents a cluster analysis method that can identify significant cell phenotypes, based on the nuclear distribution of specific proteins, with high accuracy.
Cloning and expression of a zebrafish SCN1B ortholog and identification of a species-specific splice variant
Authors: Fein Amanda J , Meadows Laurence S , Chen Chunling , Slat Emily A , Isom Lori L
Published: July 2007

Background

Voltage-gated Na+ channel β1 (Scn1b) subunits are multi-functional proteins that play roles in current modulation, channel cell surface expression, cell adhesion, cell migration, and neurite outgrowth. We have shown previously that β1 modulates electrical excitability in vivo using a mouse model. Scn1b null mice exhibit spontaneous seizures and ataxia, slowed action potential conduction, decreased numbers of nodes of Ranvier in myelinated axons, alterations in nodal architecture, and differences in Na+ channel α subunit localization. The early death of these mice at postnatal day 19, however, make them a challenging model system to study. As a first step toward development of an alternative model to investigate the physiological roles of β1 subunits in vivo we cloned two β1-like subunit cDNAs from D. rerio.

Results

Two β1-like subunit mRNAs from zebrafish, scn1ba_tv1 and scn1ba_tv2, arise from alternative splicing of scn1ba. The deduced amino acid sequences of Scn1ba_tv1 and Scn1ba_tv2 are identical except for their C-terminal domains. The C-terminus of Scn1ba_tv1 contains a tyrosine residue similar to that found to be critical for ankyrin association and Na+ channel modulation in mammalian β1. In contrast, Scn1ba_tv2 contains a unique, species-specific C-terminal domain that does not contain a tyrosine. Immunohistochemical analysis shows that, while the expression patterns of Scn1ba_tv1 and Scn1ba_tv2 overlap in some areas of the brain, retina, spinal cord, and skeletal muscle, only Scn1ba_tv1 is expressed in optic nerve where its staining pattern suggests nodal expression. Both scn1ba splice forms modulate Na+ currents expressed by zebrafish scn8aa, resulting in shifts in channel gating mode, increased current amplitude, negative shifts in the voltage dependence of current activation and inactivation, and increases in the rate of recovery from inactivation, similar to the function of mammalian β1 subunits. In contrast to mammalian β1, however, neither zebrafish subunit produces a complete shift to the fast gating mode and neither subunit produces complete channel inactivation or recovery from inactivation.

Conclusion

These data add to our understanding of structure-function relationships in Na+ channel β1 subunits and establish zebrafish as an ideal system in which to determine the contribution of scn1ba to electrical excitability in vivo.
Characterization of thimet oligopeptidase and neurolysin activities in B16F10-Nex2 tumor cells and their involvement in angiogenesis and tumor growth
Authors: Paschoalin Thaysa , Carmona Adriana K , Rodrigues Elaine G , Oliveira Vitor , Monteiro Hugo P , Juliano Maria A , Juliano Luiz , Travassos Luiz R
Published: July 2007

Background

Angiogenesis is a fundamental process that allows tumor growth by providing nutrients and oxygen to the tumor cells. Beyond the oxygen diffusion limit from a capillary blood vessel, tumor cells become apoptotic. Angiogenesis results from a balance of pro- and anti-angiogenic stimuli. Endogenous inhibitors regulate enzyme activities that promote angiogenesis. Tumor cells may express pro-angiogenic factors and hydrolytic enzymes but also kinin-degrading oligopeptidases which have been investigated.

Results

Angiogenesis induced by B16F10-Nex2 melanoma cells was studied in a co-culture with HUVEC on Matrigel. A stimulating effect on angiogenesis was observed in the presence of B16F10-Nex2 lysate and plasma membrane. In contrast, the B16F10-Nex2 culture supernatant inhibited angiogenesis in a dose-dependent manner. This effect was abolished by the endo-oligopeptidase inhibitor, JA-2. Thimet oligopeptidase (TOP) and neurolysin activities were then investigated in B16F10-Nex2 melanoma cells aiming at gene sequencing, enzyme distribution and activity, influence on tumor development, substrate specificity, hydrolytic products and susceptibility to inhibitors. Fluorescence resonance energy transfer (FRET) peptides as well as neurotensin and bradykinin were used as substrates. The hydrolytic activities in B16F10-Nex2 culture supernatant were totally inhibited byo-phenanthrolin, JA-2 and partially by Pro-Ile. Leupeptin, PMSF, E-64, Z-Pro-Prolinal and captopril failed to inhibit these hydrolytic activities. Genes encoding M3A enzymes in melanoma cells were cloned and sequenced being highly similar to mouse genes. A decreased proliferation of B16F10-Nex2 cells was observed in vitro with specific inhibitors of these oligopeptidases. Active rTOP but not the inactive protein inhibited melanoma cell development in vivo increasing significantly the survival of mice challenged with the tumor cells. On Matrigel, rTOP inhibited the bradykinin – induced angiogenesis. A possible regulation of the homologous tumor enzyme in the perivascular microenvironment is suggested based on the observed rTOP inhibition by an S-nitrosothiol NO donor.

Conclusion

Data show that melanoma cells secrete endo-oligopeptidases which have an important role in tumor proliferation in vitro and in vivo. rTOP inhibited growth of subcutaneously injected B16F10-Nex2 cells in mice. TOP from tumor cells and bradykinin in endothelial cells are two antagonist factors that may control angiogenesis essential for melanoma growth. A regulatory role of NO or S-nitrosothiols is suggested.
Are alexithymia and emotional characteristics of disclosure associated with blood pressure reactivity and psychological distress following written emotional disclosure/
Authors: O'Connor Daryl B. , Ashley Laura
Published: July 2007

Objectives This study had three aims: 1) to investigate whether cardiovascular responses to laboratory stress and levels of emotional distress were attenuated following written emotional disclosure; 2) to test, in addition to the potential main effects, whether levels of alexithymia moderated the impact of writing; and 3) to examine whether alexithymics who successfully disclosed emotion in their essays would experience positive effects following writing.

Design and methods Eighty‐seven participants wrote about their most stressful life experience or about a non‐stressful experience, for 15 minutes, over 3 consecutive days. Two weeks later, blood pressure (BP) responses to laboratory stress and levels of emotional distress were assessed. Emotional characteristics of the disclosure essays were analysed with the Linguistic Inquiry and Word Count programme and alexithymia was assessed at baseline using the Toronto Alexithymia Scale‐20.

Results Analyses found no evidence in support of the main effects of disclosure on cardiovascular responses to stress or on emotional distress. However, alexithymia was found to moderate the impact of writing such that non‐alexithymic participants in the experimental condition reported significantly lower emotional distress 2 weeks later. In addition, alexithymic participants who disclosed a greater number of negative when compared with positive emotion words exhibited reduced systolic and diastolic responses to stress. Conversely, non‐alexithymic participants who disclosed more positive and less negative emotion words displayed attenuated BP reactivity to stress.

Conclusions The results of this exploratory study are important as they highlighted, in the absence of main effects, the importance of examining potential moderators of the emotional writing process. These findings may have implications for the development of cardiovascular health interventions.
Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy
Authors: Phuong Le Xuan , Takayama Masato , Shida Satoshi , Matsumoto Yuji , Aoyagi Tetsuo
Published: July 2007

A new approach based on hydrogen-deuterium exchange is proposed for measuring accessible OH groups in wood. The deuterium (D) exchanged for hydrogen in OH groups in wood was converted to D2O by combustion in oxygen gas then diluted in deionized water, and subsequently determined by 2H NMR spectroscopy. The amount of accessible OH groups in Styrax tonkinensis wood is approximately 6.8 mmol g-1. This measurement is very accurate, with an error of approximately 0.2 mmol g-1. Heat-treated wood has a lower amount of accessible OH groups than non-treated wood. This finding is in agreement with the decreased hygroscopicity of heat-treated wood and explains, at least partially, its increased fungal resistance.
Population dynamics of four marsupials and its relation to resource production in the Atlantic forest in southeastern Brazil
Authors: Gentile Rosana , Finotti Ricardo , Rademaker Vitor , Cerqueira Rui
Published: July 2007

Variations in mammal population sizes can be related to the availability and
abundance of their resources. This study reports the population dynamics of
four didelphid marsupials (Didelphis aurita, Philander frenatus, Marmosops
incanus and Metachirus nudicaudatus) and its relation to litter fall, used as a
measure of resource production. A capture-mark-recapture study (CMR) was
carried out in a disturbed area of the Atlantic forest in Rio de Janeiro State,
Brazil, in three grids in the locality of Garrafão from April 1997 to February
1999, every other month. Litter was collected every month using 15 squared
litter traps of 0.25 m2 in the grids (5 in each grid). Leaves, twigs, reproductive
structures and total litter fall rates were calculated as tons ha–1month–1. Population densities, survivorship and recruitment rates were estimated. For
D. aurita and P. frenata, population densities were correlated positively only
with litter production. For M. incanus, population density was correlated
positively with survivorship, litter production and negatively with rainfall.
M. nudicaudatus population density was correlated only with recruitment and
twigs abundance. The availability of fruits and arthropods had a large influence
in the proximal causes on the variation of small mammal populations.
In forests where there is an adequate rate of decomposition of the litter, we
may understand how resources influence population variation, and litter
becomes the base of resources for such marsupials in the Atlantic forest.
Phase 1 study of lonafarnib (SCH 66336) and imatinib mesylate in patients with chronic myeloid leukemia who have failed prior single‐agent therapy with imatinib
Authors: Cortes Jorge , Jabbour Elias , Daley George Q. , O'Brien Susan , Verstovsek Srdan , Ferrajoli Alessandra , Koller Charles , Zhu Yali , Statkevich Paul , Kantarjian Hagop
Published: July 2007

BACKGROUND.

Lonafarnib is an orally bioavailable nonpetidomimetic farnesyl transferase inhibitor with significant activity against BCR‐ABL‐positive cell lines and primary human chronic myeloid leukemia (CML) cells. Lonafarnib can inhibit the proliferation of imatinib‐resistant cells and increases imatinib‐induced apoptosis in vitro in cells from imatinib‐resistant patients.

METHODS.

The authors conducted a phase 1 study of lonafarnib in combination with imatinib in patients with CML who failed imatinib therapy. The starting dose level for patients with chronic phase (CP) disease was imatinib, 400 mg/day, plus lonafarnib at a dose of 100 mg twice daily. The starting dose levels for accelerated phase (AP) and blast phase (BP) disease were 600 mg/day and 100 mg twice daily, respectively.

RESULTS.

A total of 23 patients were treated (9 with CP, 11 with AP, and 3 with BP) for a median of 25 weeks (range, 4–102 weeks). Of those with CP disease, 2 patients had grade 3 (according to the National Cancer Institute Common Toxicity Criteria [version 2.0]) dose‐limiting toxicities (DLTs) at the 400 + 125‐mg dose, including diarrhea (2 patients), vomiting (1 patient), and fatigue (1 patient). In patients with AP/BP disease, DLTs were observed at the 600 + 125‐mg dose and was comprised of diarrhea (1 patient) and hypokalemia (1 patient). Eight patients (35%) responded; 3 with CP disease achieved a complete hematologic response (CHR) (2 patients) and a complete cytogenetic response (1 patient). Three patients with AP disease responded (2 CHR, 1 partial cytogenetic response), and 2 patients with BP disease demonstrated hematologic improvement. Pharmacokinetics data suggest no apparent increase in exposure or changes in the pharmacokinetics of either lonafarnib or imatinib when they are coadministered.

CONCLUSIONS.

The results of the current study indicate that the combination of lonafarnib and imatinib is well tolerated and the maximum tolerated dose of lonafarnib is 100 mg twice daily when combined with imatinib at a dose of either 400 mg or 600 mg daily. Cancer 2007. © 2007 American Cancer Society.
Exact integration and its application in adaptive boundary element analysis of two‐dimensional potential problems
Authors: Zhang Xiaosong , An Xin
Published: July 2007

This paper considers the exact integration of discontinuous quadratic element for boundary element analysis of two‐dimensional potential problems. It is proved by the mathematical induction that singular integral in Cauchy principal value (CPV) and hypersingular integral in Hadamard finite part (HFP) need no special treatment with the derived exact integration for discontinuous quadratic element. The evaluation of CPV and HFP without special treatment leads to an easy way to compute the potential and flux on the boundary. The differences of the recovered flux and those by solving algebraic equation at collocation points are interpolated as error indicator for adaptive boundary element analysis. Two numerical examples are given to verify the correctness of the exact integration and the feasibility of the
proposed error indicator. Copyright © 2007 John Wiley & Sons, Ltd.
An algorithm for generating low‐autocorrelation side‐lobe binary sequences
Authors: Ohue Kenji
Published: July 2007

The finite binary sequence with low autocorrelation is applied to the smearing process to suppress impulsive noise, as well as the pulse compression in the long‐range radar. Up to now, however, a generation algorithm has not been found which can generate the binary sequence with arbitrary length, thus minimizing the autocorrelation function. This paper proposes a new generation algorithm which can derive a low‐autocorrelation binary sequence, by using the complex exponential function e−j∫f(w′dw′) as the generating function, and by the binary quantization of its Fourier expansion coefficients. It is shown first that the Fourier expansion coefficients of the generating function form an uncorrelated sequence, and then the generation algorithm is derived in detail using that property. So far, a generation algorithm has not been found that can generate the Barker sequence, which is a typical binary sequence with the minimum autocorrelation. It is shown that the proposed algorithm can generate all Barker sequences. It is also shown that the proposed method can generate a binary sequence with smaller autocorrelation than the one generated by Schroeder's method, which has been a typical generation algorithm in the past.
Cepstral analysis with nonuniform spectral weighting for spectral envelope extraction
Authors: Tokuda Keiichi , Kobayashi Takao , Imai Satoshi
Published: July 2007

This paper proposes a method for extraction of the spectral envelope by a spectral evaluation criterion with nonuniform weighting on a log magnitude scale. In the traditional cepstral method, the spectral envelope is obtained by linear smoothing on the log scale. Consequently, the obtained log magnitude spectrum is affected by the low‐level portion of the spectral fine structure, one of the factors that has degraded the quality of the synthesized speech and the speech recognition rate. to avoid such a situation, the proposed method weights the peaks of the fine spectral structure more heavily than the valleys in the error criterion. Consequently, the resultant spectral envelope fits the peaks, i.e., the sampling points of the true spectral envelope for a voiced sound. This method does not require pitch extraction. In addition, the spectral envelope can be obtained stably both for voiced and unvoiced sounds. Thus, it is suitable for the automatic analysis of speech. the effectiveness of the method is demonstrated by some examples, and its relation to other methods, especially to the improved cepstral method, is discussed.
An explicit evaluation of total variations of fourier seri approximations to functions of finite variation
Authors: Kohda Tohru , Matsuyuki Yasumi
Published: July 2007

Earlier, the authors attempted an explicit evaluation of the total variation of best piecewise polynomial approximations and obtained a result [9]. However, there, the discussion was on polynomials and cannot be applied to other families of functions. Thus, the present paper considers a similar discussion with respect to the trigonometric functions, that is, the Fourier series expansion. Specifically, the total variation of Fourier series approximations is investigated, and, in addition, the norms of Fourier coefficients are evaluated. For the norms of Fourier coefficients, we confirm that they converge to zero when the degree m → ∞ and its rate is O(m−1) (Riemann‐Lebesgue lemma). Conventionally, the norm of Fourier coefficients had been evaluated mostly by assuming the periodicity of functions to be approximated. However, in this paper, we evaluate the norm without using the periodicity condition of the approximated functions. Moreover, it is shown that the upper bound of the ratio between the total variations of K‐th partial sum of Fourier series and that of the function to be approximated, is proportional to K. This implies that compared to the evaluation of total variation of the best piecewise polynomial approximations obtained in the authors' previous paper, this evaluation excels it by far.
Optimal design of three‐dimensional FIR digital filters. Design method by linear programming and reduction of computations by exploiting symmetries
Authors: Higuchi Tatsuo , Ohki Makoto , Kawamata Masayuki
Published: July 2007

Recently, the signal processing by the three‐dimensional digital filter is considered in such applications as dynamic image processing, medical image processing, robot vision, and analysis of seismic or meteorological data. This paper proposes a method of optimum design for the three‐dimensional FIR digital filter using linear programming. the optimum design of the three‐dimensional digital filter, including the design by linear programming, requires in general a large computational complexity. From such a viewpoint, this paper discusses the reduction of computational complexity utilizing the symmetry in the frequency response, and the result is actually applied to the design by linear programming. As a result, it is shown, for the case of the spherical lowpass filter, that the computation time is reduced by one order of magnitude by utilizing the symmetry.
Elastic and piezoelectric properties of piezoelectric composite materials
Authors: Hashimoto Ken‐Ya , Yamaguchi Masatune
Published: July 2007

This paper offers theoretical and experimental examinations of the elastic and piezoelectric properties of piezoelectric composite materials used mainly for ultrasonic medical‐diagnosis apparatus. One‐dimensional multilayer composite materials in which the thickness of each layer is less than the wavelength of elastic waves (i.e., each layer can be regarded as uniform), were analyzed rigorously, and their equivalent elastic, piezoelectric, and dielectric constants were obtained. By using the results, the characteristics of a vibrator employing the one‐dimensional composite‐material (piezoelectric ceramic and epoxy resin) were examined. the relationship between the high‐coupling and low‐impedance (which are the features of this type of composite material) and the behavior of each component material was investigated. A model which evaluates the characteristics of the 1‐3 type twodimensional composite piezoelectric material (which is important for practical ultrasonic transducers) was proposed. the characteristics of a vibrator made of this material were examined. Not only can this model explain the known experimental facts, but it can easily deduce the piezoelectric constants which are important for evaluating the spurious response. A vibrator using the composite material was fabricated. Its characteristics agree reasonably well with the result of the analysis. the proposed method can be expanded for composite materials other than the 1‐3 type, and will be useful for the design and development of general compound materials.
Instruments for displaying the Lorenz maps and the Poincaré maps on a synchroscope
Authors: Itoh Makoto , Tomiyasu Ryuichi
Published: July 2007

This paper outlines the new instruments for displaying Lorenz maps and Poincaré maps on a synchroscope. These instruments are designed using only a few ICs, and, as a result, they are easily built. Next, we present the observation examples of the forementioned two maps obtained from the chaotic circuit. Furthermore, it is shown that the shape of the maps depends not on the nature of uncertain factors, but on the structure of the bundle of the solutions.
Linear phase FIR digital filters using interpolated equalizers
Authors: Honma Hitoshi , Yamada Masakazu , Sagawa Masahiko
Published: July 2007

A method for designing an FIR digital filter is reported with a view to reducing the number of multipliers and addres. an effective method for reducing the number of multipliers and addres is the one in which a prefilter without a multiplier and an equalizer (compensating the characteristics to satisfy the given specifications) are cascaded. In previous studies on this method, the design of the prefilter was the main topic and no sufficient attention was given to the equalizer. In the present method, the design method of the equalizer is also studied. A new design method for an equalizer is proposed in which a concept of interpolation is introduced. the present method is applied to a number of examples. It is confirmed that a significant reudtion of the number of multipliers and addres is obtained.
Normalized ARMA lattice filter and its terminal conditions
Authors: Haseyama Miki , Nagai Nobuo , Miki Nobuhiro , Miyanaga Yoshikazu
Published: July 2007

In this paper it is shown that covariant data of a synthesized signal corresponds to the covariant data of a real signal.

This occurs when an ARMA lattice synthesis filter is used and the minimum mean square value of the estimation error is zero.

Hence, a new terminal condition of the ARMA lattice filter is derived so that the covariant data of the synthesized signal will always correspond to the covariant data of a real signal.

To this end, a design method for the normalized ARMA lattice filter is presented in this paper, and normalized estimation errors are derived. Finally, the starting condition and design for the normalized ARMA lattice filter is given.
Universal learning machine and application to english type‐letter recognition
Authors: Suzuki Hisashi , Arimoto Suguru
Published: July 2007

This paper proposes a universal learning machine (ULM) that absorbs information from environments and acquires an ability to process information professionally according to the environments. Additionally, it applies this information to the recognition of the English type‐letters that are highdensely printed in magazines, books, etc. A window is applied on a black and white image gathered through an image scanner so that only a letter and a head part of the succeeding letter can be observed. Appropriately fixing a distance that measures the similarity between the window images, the recognizer utilizing the ULM searches for some one of the most similar window images to the current from among the window images memorized in the past. Then the recognizer loads the records accompanying it to display for a user the reading of the designated letter and the boundary between this letter and the succeeding letter. the user commands whether the recognizer should revise the memory or continue the recognition process. If the command is for revision, the content of revision is memorized in the form of a binary tree while part of the content memorized in the past is deleted to prevent overflow in system memory capacity. A theoretical evaluation of the performance of the ULM and an experimental evaluation on the English type‐letter recognizer actually constructed are performed.
Frequency spectrum estimation method using complex Kalman filter
Authors: Nishiyama Kiyoshi , Mita Tutomu
Published: July 2007

As a method to estimate the frequency spectrum, the discrete Fourier transform is employed widely, since a high‐speed algorithm is available. However, the discrete Fourier transform has the following problems. the presence of noise is not considered, and the resolution of the frequency spectrum is determined uniquely by the sample duration. Other problems are that the sampling interval must be kept constant and the decay of the signal is not considered. This paper proposes a high‐resolution frequency spectrum estimation where the complex Kalman filter is applied to the observed signal represented by the complex stochastic system, effectively utilizing the a priori knowledge of the signal source. the method is applied to the measured data and to the simulation, and it is demonstrated that a high‐resolution frequency spectrum is obtained by suppressing the effect of the discrete approximation of the frequency component, and, when the frequency spectrum is concentrated, the resolution can be improved approximately by a factor of two, without iterating the measurement. It is shown also that the sampling interval can be set arbitrarily in the proposed method, and the noise and the decay can be considered. A theoretical discussion is made on the relation between the special case of the proposed method and the discrete Fourier transform.
Stability domain of the second‐order discrete oscillatory system with parametric excitation
Authors: Tanaka Toshiyuki , Sato Chikara
Published: July 2007

This paper presents a quantitative discussion on the stability of the second‐order periodic difference equation, which characterizes the discrete periodic time‐varying system. the periodic parameter discrete system, which corresponds to Mathieu's equation in the continuous system, is represented by a second‐order linear difference equation with a small parameter ε in the varying term. the parameter ε plays an important role in the determination of the stability. By applying McLachlan's method, the expression for the boundary between the stability and the instability can be determined analytically with regard to the parameters contained in the equation. For the case where the periodic parameter of the difference equation is represented as a sum of two even functions, the boundary between stability and instability is determined. the stability can be analyzed in a similar way for the case where the periodic parameter is represented as a sum of N even functions in Fourier series.
Updating of all the shortest paths
Authors: Izumi Takashi , Takahashi Yutaka , Kawanishi Kenji
Published: July 2007

There are times when updating of shortest paths is required when a part of a network structure, such as length of a branch, is altered. For updating shortest paths, information on already obtained shortest paths including mid‐progresses can be used. Many of the algorithms shown so far are aimed at altering the length of one branch in a network or some branches going in or out at a node. With these algorithms, it is necessary to repeat the application if there are simultaneous alterations of multiple branches other than described in the foregoing, and the efficiency is not always good in terms of computation steps. This paper describes an algorithm which updates shortest paths between all pairs of nodes when simultaneous alterations of lengths of multiple branches, with no restriction to branches going in/out at one node, are allowed. In terms of computation steps, our algorithm is more efficient than repeatedly applying conventional methods.
An efficient probabilistic algorithm for solving quadratic equation over finite fields
Authors: Itoh Toshiya
Published: July 2007

The probabilistic algorithm has a random procedure, which may or may not produce the solution, due to its randomness. By iterating the application, the desired solution can be produced with a high probability (unless the probability that the probabilistic algorithm produces the solution is very low). In 1980, Rabin proposed a probabilistic algorithm to solve a higher‐order equation over a finite field. When his algorithm is applied to the quadratic equation on a finite field, the probability that the desired solution is obtained by one application is 1/2, and the root can be determined by two times applications on the average. This paper proposes a probabilistic algorithm in which the probability that the desired solution is obtained by one application is kept as one‐half, and the quadratic equation over the finite field GF(p) (where p is an odd prime number) or GF(2m) is solved more efficiently than by Rabin's method. the proposed algorithm calculates the solution more efficiently than Rabin's method by determining the random parameter to be set in finding the solution, using a procedure which can efficiently be executed before calculation.
Correction theory and algorithm for reachability matrix model
Authors: Kase Satoshi , Ohuchi Azuma , Kaji Ikuo
Published: July 2007

A reachability matrix M is a binary matrix with the reflexive and transitive property, i.e., M + I = M and M2 = M, where I is the identity matrix. Reachability matrices are used to identify structural models of complex systems. While a structural model is being developed or after it has been developed, the developer may want to make changes in it. Procedures for changing a structural model with computer assistance are called “correction procedures.” Several algorithms for correction procedures of the partially filled reachability matrix are de scribed.
Monotonic properties for the responses of a class of CMOS circuits
Authors: Urahama Kiichi
Published: July 2007

This paper considers a CMOS circuit which is composed of inverter‐type gates, transfer gates, and connections. the properties of the equivalent circuit obtained by replacing those elements by circuit models are discussed. It is shown that if all inverter‐type gates in the circuit can be given signs so that different signs are adjacent to each other, the response waveform of the circuit depends monotonically on the initial value, input and the transistor parameters.
Estimation of the frquency of a sinusoidal wave signal with short record length
Authors: Konishi RyōSuke , Matsumoto Shigeharu , Sasakura Hiroshi
Published: July 2007

This paper presents a new method of an accurate estimation of a sinusoidal wave signal with short record‐length and with noise. the method is based on the linear prediction model (L.P. model). Although a conventional L.P. model is known to be an accurate method for estimating a sinusoidal wave with a short record‐length, the authors found that even minor noise degrades its accuracy significantly. to improve this noise dependence, the authors introduced two new algorithms: (1) restriction of the coefficient value in the linear prediction equation; and (2) averaging of frequencies which are obtained from the time delay τ around a point where the sign of the coefficient reverses. the results obtained by this method show that the frequency‐estimation error is reduced to one‐fifth to one‐ tenth that obtained by a conventional L.P. model when the record length corresponds ‐to 1.2 period of a sinusoidal wave with noise, confirming the effect of the proposed method.
On the LP‐HP transformation in SCF
Authors: Ishikawa Masayuki , Fujii Nobuo
Published: July 2007

To realize a highpass filter structure from a lowpass one, one can use the lowpass‐ highpass transformation (LP‐HP transformation) technique. This technique can easily be applied to passive LC filters, active RC filters, and digital filters. However, the direct application of the LP‐HP transformation to SCF's has not been reported. This paper shows that the LP‐HP transformation by replacing z with ‐z as is used in digital filters, is applicable to SCF's. We can easily obtain highpass characteristics from a lowpass SCF by adding a simple transforming circuit to the lowpass SCF. In addition, the HPF obtained from its LPF structure can have low element sensitivities and a narrow element value range.
Cluster‐based management of large computer networks. Computational complexity of initial clustering problem
Authors: Ishida Kenji , Miyao Jun'Ichi , Kikuno Tohru , Yoshida Noriyoshi
Published: July 2007

One of the interesting issues in the management of large computer networks is to partition the network into clusters and then to perform the management for each cluster. This paper presents a basic discussion on the initial clustering problem for a given network. the initial clustering problem C is defined as follows. Given a graphic representation G=(V, E), [V] = n of a network and a set of nodes C=[ci]1≤ i ≤ m ≤ V, the graph G is to be partitioned into m connected subgraphs Gi = (V≤ E≤) ( 1 ≤ i ≤ m) of G satisfying the following conditions: ≤ V, ≤ (a positive integer); and ≤ the distance between ≤ Vi and ≤ is minimum when × = i. the following results were obtained for the time complexity of the problem C: (1) the initial clustering problem C is in general NP‐hard; and (2) the sub‐problem obtained by deleting the condition ≤ can be solved in O (n2).
Design of multirate FIR digital filters with arbitrary passband
Authors: Hirai Ryoji , Ikehara Masaaki , Takahashi Shinichi
Published: July 2007

This paper proposes a new method of con structing the multirate FIR digital filter with arbitrary passband, using real‐coefficient filters for the decimator and interpolator composing the multirate filter. It is already known that the bandpass filter can easily be realized using the complex‐coefficient filter. In such a construction, however, the processing of the analytic signal is required using Hubert transform, which makes the whole system somewhat complex. From such a viewpoint, this paper pre sents a method of constructing the multirate bandpass digital filter using the real‐coefficient filter. Another method is also presented, where the muitirate lowpass filter with arbitrary passband can be constructed by combining the complementary response and a lowpass filter. the multirate method is effective in realizing a narrowband response, but may not be useful in realizing a relatively wideband response. By the proposed method, the latter can easily be realized, drastically reducing the number of multiplications. Similar methods can be applied to highpass and bandstop filters.
A high‐speed parallel FFT‐processor for a radio astronomy telescope
Authors: Iwase Seiichiro , Okita Toshimichi , Yamazaki Takao , Daishido Tsuneaki , Asuma Kuniyuki
Published: July 2007

A radio astronomy telescope with a wide field of view is an efficient tool for locating such transient radio sources in space as supernova explosions. A promising method of designing this type of telescope is to apply Fourier transformation to the output signals from a phased array antenna. the implementation of a high‐speed parallel FFT processor to an eight‐element linear phased array antenna output is reported in this paper. Small size and low‐power con sumption are achieved by utilizing conventional digital video signal processing LSIs. In the present pilot system, arithmetic operation up to a speed of 2.7 COPS (giga operations per second) has been attained. the basic operation has been confirmed by solar observation.
Compression of digital images based on vector quantization with variable block size
Authors: Yahagi Takashi , Suga Akira , Takamura Matsuzo
Published: July 2007

The vector quantization recently has been considered interesting as a highly efficient coding for compressing digital images. For this purpose, the predictive coding and the transform coding have been known, but the vector quantization can realize the coding with fewer bits per pixel, which is a drastic compression compared with past methods. the image contains parts with different local properties such as parts with rapid intensity changes such as edge, and parts with slow intensity changes such as flat part. If this situation is taken into consideration, a more efficient coding can be realized. In the usual vector quantization, the overall image is divided into blocks of a constant size. In the coding based on the local property of the image, however, it is desirable to use blocks with variable sizes rather than a constant size. From such a viewpoint, this paper proposes a new vector quantization in which the block size resulting from the division is adjusted adaptively according to the local property of the image. First, the vector quantization with variable block size is described in detail. Then the proposed method is applied in several simulation problems, and the actual usefulness of the method using variable block sizes is demonstrated.
Deconvolution filtering for the high‐resolution ultrasonic pulse‐echo measurement
Authors: Yamada Akira
Published: July 2007

In the ultrasonic pulse‐echo measurement system, the deconvolution signal processing enables maximum information to be extracted from the echo signal under the physical restriction of the acoustic propagation loss, thereby realizing significant improvement of the resolution capability. This paper presents the deconvolution filtering technique which satisfies the practical requirements for the mitigation of noise amplification compatible with a simple fast procedure. Specifically, the time‐domain deconvolution filter is determined in such a way that the second‐order moment of the desired response is minimized under the band‐limited condition, thereby optimizing the filter coefficient subject to the constraints of the small processing noise. In addition, the envelope detection is incorporated for the removal of the distortion due to the band‐limited nature of the signal. Furthermore, the theoretical formula for the range resolutions achievable with this technique is derived. At the end of this paper, results of the evaluation experiments are shown to demonstrate that high‐resolution measurement comparable to the theoretical limit is obtained with small processing noise.