bluuebunny/crossref_metadata_2025 huggingface dataset:
Exogenous cadherin microdisplay can interfere with endogenous signaling and reprogram gene expression in cultured hepatocytes
Authors: Brieva Thomas A. , Moghe Prabhas V.
Published: January 2004

We recently found that the basal micro substrate presentation of E‐cadherin, a key cell–cell adhesion molecule in the liver, can modulate hepatocellular proliferative potential and differentiated function (Brieva and Moghe, in press). In the current study, we established a similar experimental model involving rat hepatocytes cultured on collagen and incorporated 5 μm polystyrene microbeads functionalized with Protein A‐anchored E‐cadherin/human lgG Fc chimeric fusion constructs. We investigated the cadherin governed dose‐response of cell proliferative potential and quantified the underlying changes in intracellular gene signaling processes. Hepatocellular proliferative potential was found to be intensified with an increase in the microdisplay of acellular cadherins and this effect was offset by increased cell seeding density. Notably, we report that following overnight exposure to acellular cadherins, the expression of genes known to mediate the control of cell proliferation, cyclin D1 and c‐myc, was upregulated, while the expression of differentiation‐related genes, namely albumin and cytochrome P450 II B1, was reduced. The exposure of cell cultures to exogenous cadherins was found to markedly disrupt the localization of endogenous E‐cadherin and β‐catenin to junctions at cell–cell contacts and cause a quantitative decrease in the endogenous cadherin protein levels. Based on all of our observations, we propose that the acellular presentation of E‐cadherin chimeras competitively disrupts endogenous cadherin containing complexes at cell–cell junctions and increases intracellular cadherin turnover, thereby promoting β‐catenin mediated signaling, which ultimately engenders an increase in cell proliferative potential and a decrease in differentiated function. © 2004 Wiley, Periodicals, Inc.
Penicillin acylase‐catalyzed synthesis of β‐lactam antibiotics in highly condensed aqueous systems: Beneficial impact of kinetic substrate supersaturation
Authors: Youshko Maxim I. , Moody Harold M. , Bukhanov Alexander L. , Boosten Wilhelmus H. J. , Švedas Vytas K.
Published: January 2004

Advantages of performing penicillin acylase‐catalyzed synthesis of new penicillins and cephalosporins by enzymatic acyl transfer to the β‐lactam antibiotic nuclei in the supersaturated solutions of substrates have been demonstrated. It has been shown that the effective nucleophile reactivity of 6‐aminopenicillanic (6‐APA) and 7‐aminodesacetoxycephalosporanic (7‐ADCA) acids in their supersaturated solutions continue to grow proportionally to the nucleophile concentration. As a result, synthesis/hydrolysis ratio in the enzymatic synthesis can be significantly (up to three times) increased due to the nucleophile supersaturation. In the antibiotic nuclei conversion to the target antibiotic the remarkable improvement (up to 14%) has been gained. Methods of obtaining relatively stable supersaturated solutions of 6‐APA, 7‐ADCA, and D‐p‐hydroxyphenylglycine amide (D‐HPGA) have been developed and syntheses of ampicillin, amoxicillin, and cephalexin starting from the supersaturated homogeneous solutions of substrates were performed. Higher synthetic efficiency and increased productivity of these reactions compared to the heterogeneous “aqueous solution‐precipitate” systems were observed. The suggested approach seems to be an effective solution for the aqueous synthesis of the most widely requested β‐lactam antibiotics (i.e., amoxicillin, cephalexin, cephadroxil, cephaclor, etc.). © 2004 Wiley Periodicals, Inc.
Poly‐3‐hexyl thiophene Langmuir‐Blodgett films for application to glucose biosensor
Authors: Singhal Rahul , Chaubey Asha , Kaneto Keiichi , Takashima W. , Malhotra B. D.
Published: January 2004

Langmuir‐Blodgett films of poly(3‐hexyl thiophene) have been prepared by simultaneous entrapment of glucose oxidase and transferred onto the indium‐tin‐oxide coated glass plates. The films have been characterized by FTIR spectroscopy and detailed response studies have been performed with respect to glucose concentration, temperature, and storage time. These P3HT/SA/GOX electrodes have been utilized for glucose estimation from 100–500 mg/dL by amperometric method. The electrodes have been found to have sensitivity of 0.75 nA/mg/dL detection limit of 50 mg/dL and shelf life of about 75 days at 4°C. © 2004 Wiley Periodicals, Inc.
On‐line monitoring of important organoleptic methyl‐branched aldehydes during batch fermentation of starter culture Staphylococcus xylosus reveal new insight into their production in a model fermentation
Authors: Petersen Christian de Vos , Beck Hans C. , Lauritsen Frants R.
Published: January 2004

A small fermentor (55 mL) was directly interfaced to a membrane inlet mass spectrometer for continuous on‐line monitoring of oxygen and volatile metabolites during batch fermentations of the starter culture Staphylococcus xylosus. Using this technique, we were able to correlate production of the very important flavor compounds 2‐methylbutanal, 3‐methylbutanal, and 2‐methylpropanal with various growth conditions. We found that the aldehydes were present in the culture broth only as transient metabolites. They were produced in the exponential growth phase, reached a maximum concentration when the culture became anaerobic, and then they rapidly disappeared from the culture medium. This general pattern was observed for three different strains of S. xylosus and S. carnosus. Small amounts of inoculum or increased exposure to oxygen were found to favor production of the aldehydes as a result of a longer aerobic growth period. Growing S. xylosus under conditions resembling those in a fermented sausage revealed that NaCl (5%) increased aldehyde production considerably, whereas KNO3 (0.03%) or NaNO2 (0.03%) had little effect. A lowering of pH from 7.2 to 6.0 reduced cell density, but had a minor affect on aldehyde production. © 2004 Wiley Periodicals, Inc.
Affinity purification of plasmid DNA by temperature‐triggered precipitation
Authors: Kostal Jan , Mulchandani Ashok , Chen Wilfred
Published: January 2004

This report describes a new plasmid DNA purification method, which takes advantage of the DNA‐binding affinity and specificity of the bacterial metalloregulatory protein MerR, and of the temperature responsiveness of elastin‐like proteins (ELPs). Upon increasing the temperature, ELP undergoes a reversible phase transition from water‐soluble forms into aggregates, and this property was exploited for the precipitation of plasmid DNA containing the MerR recognition sequence by a simple temperature trigger. In one purification step, plasmid DNA was purified from E. coli cell lysates to a better purity than that prepared by a standard alkaline purification method, with no contaminating chromosomal DNA and cellular proteins. This protein‐based approach, in combination with the reversible phase transition feature of ELP, makes the outlined method a promising candidate for large‐scale purification of plasmid DNA for sensitive applications such as nonviral gene therapy or DNA vaccines. © 2004 Wiley Periodicals, Inc.
Transglutaminase‐mediated modification of glutamine and lysine residues in native bovine β‐lactoglobulin
Authors: Nieuwenhuizen Willem F. , Dekker Henk L. , Gröneveld Toos , de Koster Chris G. , de Jong Govardus A. H.
Published: January 2004

Bovine β‐lactoglobulin (BLG) is a major component in whey and its physical properties are important for the texture of many dairy‐based foods. Modification of proteins with transglutaminase from Streptoverticillium mobaraense (MTGase) can be used to alter their physical properties. MTGase‐mediated modification of native BLG was until now, however, not effective. Here we report a method that allows for the enzymatic modification of native BLG with MTGase. Lysines 8, 77, and 141 were modified with α‐N‐carbobenzyloxy‐glutamine‐glycine and glutamines 35, 59, 68,and 155 were modified with 6‐aminohexanoic acid under nonreducing and nondenaturing conditions. MTGase‐mediated BLG crosslinking is hampered by the low reactivity of the lysines and enzymatic deamidation of the glutamines prevails. Modification of BLG with poly‐lysine yields a BLG derivative with increased affinity for the water–air interface and stronger surface tension lowering capacities than normal BLG. Hence, this modification method offers the opportunity to change the functional properties of BLG and to prepare novel protein foods. © 2004 Wiley Periodicals, Inc.
Genome‐wide transcriptional response of a Saccharomyces cerevisiae strain with an altered redox metabolism
Authors: Bro Christoffer , Regenberg Birgitte , Nielsen Jens
Published: January 2004

The genome‐wide transcriptional response of a Saccharomyces cerevisiae strain deleted in GDH1 that encodes a NADP+‐dependent glutamate dehydrogenase was compared to a wild‐type strain under anaerobic steady‐state conditions. The GDH1‐deleted strain has a significantly reduced NADPH requirement, and therefore, an altered redox metabolism. Identification of genes with significantly changed expression using a t‐test and a Bonferroni correction yielded only 16 transcripts when accepting two false‐positives, and 7 of these were Open Reading Frames (ORFs) with unknown function. Among the 16 transcripts the only one with a direct link to redox metabolism was GND1, encoding phosphogluconate dehydrogenase. To extract additional information we analyzed the transcription data for a gene subset consisting of all known genes encoding metabolic enzymes that use NAD+ or NADP+. The subset was analyzed for genes with significantly changed expression again with a t‐test and correction for multiple testing. This approach was found to enrich the analysis since GND1, ZWF1 and ALD6, encoding the most important enzymes for regeneration of NADPH under anaerobic conditions, were down‐regulated together with eight other genes encoding NADP(H)‐dependent enzymes. This indicates a possible common redox‐dependent regulation of these genes. Furthermore, we showed that it might be necessary to analyze the expression of a subset of genes to extract all available information from global transcription analysis. © 2004 Wiley Periodicals, Inc.
Detection, isolation, and characterization of exopolysaccharide produced by a strain of Phormidium 94a isolated from an arid zone of Mexico
Authors: Vicente‐García Valeria , Ríos‐Leal Elvira , Calderón‐Domínguez Georgina , Cañizares‐Villanueva Rosa Olivia , Olvera‐Ramírez Roxana
Published: January 2004

Phormidium 94a, a cyanobacteria that produces extracellular polymeric substances (EPS), was isolated from arid soils of Mexico. Microscopic localization, using histochemical techniques like the Toluidine blue technique, was done in order to demonstrate the presence of EPS. Acetone was added to precipitate the EPS. In this study we characterized the EPS by GC, HPLC, and IR techniques. The highest fraction of EPS had a molecular weight of 2,000 kDa. The sugar composition was galactose, mannose, galacturonic acid, arabinose, and ribose in the three main fractions, and the sugar ratio found was different in each fraction. The low EPS concentrations had a Newtonian behavior, when the concentrations were increased, the behavior changed to pseudoplastic. The EPS rheulogical behavior is similar to low viscosity arabic gum. Also, it was found that an increase in viscosity occurred at longer hydration time. More rheological and toxicological studies are required in order to analyze its possible application in food industries. © 2004 Wiley Periodicals, Inc.
Absolute stability of a class of neural networks with unbounded delay
Authors: Zhang Jiye
Published: January 2004

In this paper, the existence and uniqueness of the equilibrium point and absolute stability of a class of neural networks with partially Lipschitz continue activation functions are investigated. The neural networks contain both variable and unbounded delays. Using the matrix property, the necessary and sufficient condition for the existence and uniqueness of the equilibrium point of the neural networks is obtained. By constructing proper vector Liapunov functions and non‐linear integro‐differential inequalities involving both variable delays and unbounded delay, the sufficient conditions for absolute stability (global asymptotic stability) are obtained. Copyright © 2004 John Wiley & Sons, Ltd.
A matrix pencil approach to the local stability analysis of non‐linear circuits
Authors: Riaza Ricardo
Published: January 2004

This paper addresses local stability issues in non‐linear circuits via matrix pencil theory. The limitations of the state–space approach in circuit modelling have led to semistate formulations, currently framed within the context of differential‐algebraic equations (DAEs). Stability results for these DAE models can be stated in terms of matrix pencils, avoiding the need for state–space reductions which are not advisable in actual circuit simulation problems. The stability results here presented are applied to electrical circuits containing non‐linear devices such as Josephson junctions or MOS transistors. Copyright © 2004 John Wiley & Sons, Ltd.
An interval algorithm for finding all solutions of non‐linear resistive circuits
Authors: Yamamura Kiyotaka , Igarashi Naoya
Published: January 2004

In this letter, an efficient algorithm is proposed for finding all solutions of non‐linear (not piecewise‐linear) resistive circuits. This algorithm is based on interval analysis, the dual simplex method, and the contraction methods. By numerical examples, it is shown that the proposed algorithm could find all solutions of systems of 500–700 non‐linear circuit equations in acceptable computation time. Copyright © 2004 John Wiley & Sons, Ltd.
The vasodilatory actions of insulin on resistance and terminal arterioles and their impact on muscle glucose uptake
Authors: Clerk Lucy H. , Vincent Michelle A. , Lindner Jonathan R. , Clark Michael G. , Rattigan Stephen , Barrett Eugene J.
Published: January 2004

Whether a discrete vascular action of insulin in skeletal muscle integrally participates in insulin‐mediated glucose disposal has been extensively examined but remains a contentious issue. Here, we review some of the data both supporting and questioning the role of insulin‐mediated increases in limb blood flow in glucose metabolism. We advance the hypothesis that controversy has arisen, at least in part, from a failure to recognize that insulin exerts at least three separate actions on the peripheral vasculature, each with its own characteristic dose and time responsiveness. We summarize how, viewed in this manner, certain points of contention can be resolved. We also advance the hypothesis that an action on the precapillary arteriole may play the dominant role in mediating perfusion‐dependent effects of insulin on glucose metabolism in muscle. Copyright © 2003 John Wiley & Sons, Ltd.
Soluble adhesion molecules in Finnish schoolchildren with signs of preclinical type 1 diabetes
Authors: Toivonen Anna , Kulmala Petri , Rahko Jukka , Ilonen Jorma , Knip Mikael
Published: January 2004

Background

We measured the circulating concentrations of the soluble forms of intercellular adhesion molecule‐1, ICAM‐1 (sCD54) and L‐selectin (sCD62L) in 104 non‐diabetic Finnish schoolchildren testing positive for one or more diabetes‐associated autoantibodies and in 104 autoantibody‐negative children to elucidate the relationship between soluble adhesion molecules and humoral, genetic and metabolic markers of preclinical type 1 diabetes.

Methods

Specific enzyme‐linked immunosorbent assays were used to analyse serum sICAM‐1 and sL‐selectin concentrations.

Results

The sICAM‐1 and sL‐selectin levels were comparable in the autoantibody‐positive and control children, even when comparing children with multiple autoantibodies with those having one or no autoantibodies. The IA‐2A titres in children testing positive for this autoantibody correlated with the sICAM‐1 concentrations (rs = 0.62, P = 0.05), but otherwise no significant associations were seen between the autoantibody specificities and the concentrations of soluble adhesion molecules. Control children with HLA DQB1 genotypes conferring a low or decreased risk of type 1 diabetes had higher levels of sL‐selectin than those with high or moderate risk genotypes (P = 0.04). sL‐selectin concentrations were significantly increased in the autoantibody‐positive children with a first‐phase insulin response (FPIR) below the 5th (n = 11;P = 0.026) or 10th percentiles (n = 17;P = 0.009) relative to the children with a normal FPIR. No associations were observed between sICAM‐1 concentrations and DQB1 genotypes or FPIR.

Conclusions

The data indicate that there are a few conspicuous signs of endothelial/leukocyte activation reflected in increased circulating levels of soluble adhesion molecules in schoolchildren who are positive for markers of preclinical type 1 diabetes. The correlation between sICAM‐1 concentrations and IA‐2A levels in the IA‐2A‐positive children suggests that the former may increase in late preclinical type 1 diabetes, as IA‐2A are the last autoantibodies to appear in the prediabetic process. Increased sL‐selectin concentrations in subjects with impaired β‐cell function may reflect an active destructive insulitis process. Copyright © 2004 John Wiley & Sons, Ltd.
The role of the sodium hydrogen exchanger‐1 in mediating diabetes‐induced changes in the retina
Authors: Cukiernik Mark , Hileeto Denise , Downey Donal , Evans Terry , Ali Khan Zia , Karmazyn Morris , Chakrabarti Subrata
Published: January 2004

Background

The sodium hydrogen exchanger (NHE) is a transmembrane protein responsible for alkalinization and control of intracellular acidosis by the removal of hydrogen and the subsequent influx of sodium. Our investigation attempts to determine the role of NHE‐1 in the pathogenesis of early retinal microangiopathy due to diabetes.

Methods

Diabetes was induced in male Sprague–Dawley rats with a single intravenous streptozotocin injection (65 mg/kg). To examine the duration‐dependent changes in NHE‐1 expression, retinas from 1‐, 6‐ and 12‐week diabetic animals were analyzed. To examine the functional consequences of NHE‐1 inhibition in comparison with good blood glucose control, diabetic rats were randomly assigned to poorly controlled diabetic, well‐controlled diabetic, poorly controlled diabetic with cariporide groups and were compared with nondiabetic controls after six weeks. Cariporide is an orally active inhibitor of NHE‐1 (6000 ppm in rat chow). At the end of the treatment period, color Doppler ultrasound was used to determine the resistivity index (RI) of the central retinal artery. The mRNA expression of endothelin (ET) isoforms 1 and 3, inducible and endothelial nitric oxide synthase (iNOS and eNOS respectively) and NHE‐1 were examined. NHE‐1 distribution was localized with immunohistochemistry.

Results

All diabetic animals showed hyperglycemia, increased glycated hemoglobin and lower body weight gain compared to nondiabetic controls. Diabetes caused an increased RI, indicative of retinal vasoconstriction, which was corrected by both cariporide treatment and good glucose control. NHE‐1 was localized in the endothelium of the retinal microvasculature and the neuronal and glial components. NHE‐1 mRNA expression was unchanged after 1 week and increased after 6 and 12 weeks of diabetes. Furthermore, a diabetes‐induced upregulation of ET‐1 and ET‐3 mRNA expression after six weeks was corrected with cariporide treatment. NHE‐1 inhibition of diabetic animals upregulated iNOS mRNA levels, although expression of eNOS and iNOS mRNA were not altered in poorly controlled diabetes. Improved blood glucose control with higher doses of insulin also corrected diabetes‐induced increased RI by upregulating eNOS and iNOS mRNA expression.

Conclusions

The results of the study suggest that NHE‐1 may be involved in the regulation of several vasoactive modulators that contribute to functional alterations in diabetic retinal microangiopathy. Copyright © 2004 John Wiley & Sons, Ltd.
Dynamic approach to learning disability assessment: DLD test
Authors: Dwairy Marwan
Published: January 2004

A severe discrepancy between intellectual ability and achievement is one major criterion for diagnosis of learning disability (LD). This manuscript describes the shortcomings of this paradigm and offers a new dynamic approach for LD assessment based on evaluation of LD during a standard learning process of how to read and write a new language. The dynamic learning disability (DLD) test, K‐ABC IQ test, and K‐ABC reading test were administered to 56 normal 4th grade students and to 48 LD students. It was hypothesized that the results using the conventional criteria may mismatch the results of DLD, and that DLD predicts the progress of students in a long‐term group learning process better. The results indicated that LD students, as a group, manifested significant difficulties in the DLD test. Among 48 students who meet the conventional criteria for LD diagnosis 14 students (29.16%) were able to learn a new language in the DLD test (Inconsistent LD sub‐group). From the 14 students who have low achievement in reading without serious indications of cognitive difficulties, six students (42.857%) manifested serious difficulties in learning a new language in the DLD test (Latent LD sub‐group). The DLD test as well as the labels of the sub‐groups was validated by the amount of progress in the long‐term group learning process. The DLD test proved to have high reliability and predictive validity coefficients. It is suggested that it become part of the diagnostic battery of tests of LD. Copyright © 2004 John Wiley & Sons, Ltd.
Adults with dyslexia show deficits on spatial frequency doubling and visual attention tasks
Authors: Buchholz Judy , McKone Elinor
Published: January 2004

We examine the visual processing of high‐functioning adults with developmental dyslexia (mean Performance IQ=126.5) and current phonological problems. In comparison to an age‐ and IQ‐matched control group, the group with dyslexia showed deficits in two tasks associated with magnocellular/dorsal pathway function. For the ‘frequency doubling’ stimulus (grating of 0.25 cpd modulated at 25 Hz counterphase flicker), contrast thresholds for detection were raised in the dyslexic group. In conjunction visual search, a display time sufficient for controls to achieve ceiling accuracy at all set sizes (30 ms per item) was inadequate to allow shifts of attention around the display for the group with dyslexia. In contrast, normal performance was found on ‘popout’ visual search and on a ventral stream acuity task. Correlational analysis revealed a significant relationship between degree of deficit in conjunction search and phonological difficulty. The deficits revealed were specific to functions that rely on magnocellular input. They cannot be attributed to concentration lapses, eye movement problems or slow reaction times in the dyslexic group. Copyright © 2004 John Wiley & Sons, Ltd.
Investigating learning deficits associated with dyslexia
Authors: Pothos Emmanuel M. , Kirk Jane
Published: January 2004

An artificial grammar learning task was used to define two learning tasks of identical complexity at the symbolic level, but which differed in terms of stimulus format. The stimuli in one learning task were created so as to encourage participants to perceive each stimulus as a whole, with less emphasis on the stimulus constituent elements (the ‘embedded’ stimuli), while in the second task the constituent elements of each stimulus were emphasized by presenting them serially (the ‘sequences’ stimuli). Using a between participants design, dyslexic participants performed equally well in the two versions of the learning task. By contrast, non‐dyslexic participants performed as well as dyslexic ones with the embedded stimuli but were impaired in the sequences stimuli. This finding was interpreted as showing that dyslexic participants were less able, compared to controls, to process individual stimulus elements of both the sequences and the embedded stimuli, consistently with recent work associating dyslexia with problems in attention focusing and shifting. Copyright © 2004 John Wiley & Sons, Ltd.
Space‐frequency maximal ratio combining for low‐elevation radar target
Authors: Inaba Takayuki , Araki Kiyomichi
Published: January 2004

When tracking radar is used for tracking a low‐altitude target, fading due to multipath propagation consisting of the direct wave and the waves reflected from the sea surface (or the ground) is generated so that tracking becomes difficult. In this paper, as a remedy to this problem, a space‐frequency maximum‐ratio combining method is proposed that combines frequency hopping with an array antenna. In order to reduce the size of the transmission and reception system, and also to reduce the computational overhead for maximum‐ratio combining, a subarray configuration is used for the array antenna and the maximum‐ratio combining is applied to the subarray. By means of computer simulation, the effects of the space‐frequency maximum‐ratio combining in the full DBF and in the subarray configuration are compared. It is confirmed that a power level higher than that in free space can be obtained by the proposed method under the constraint of a distance of 5000 to 40,000 m for a target at an altitude of 100 m (constant) by letting the frequency hopping range be 20%. It is also confirmed that the diversity gain degradation due to the subarray configuration is small. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(5): 75–85, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10143
Microwave imaging by quasi‐inverse scattering
Authors: Hasegawa Tomonori , Iwasaki Takashi
Published: January 2004

In this paper, a new reflection‐type microwave imaging method is proposed to compute inverse scattering in the spatial domain by means of an approximate inverse integral transform. Its effectiveness is demonstrated by simulation and experiment. Since the transmitting antenna and the receiving antenna are placed in close proximity in the reflection‐type configuration, the coupling between the transmitting and receiving antennas cannot be neglected. Also, if the operating bandwidth is increased in order to enhance the range resolution, the frequency dependence of the antenna becomes a problem. In order to resolve these problems, a new preprocessing method is proposed in which the effect of the antenna system is calibrated. Considering the wavelength and the object size, excellent reconstructed images can be obtained experimentally. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(5): 52–61, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10147
Multiserver OS for control systems: Its structure and intertask messaging efficiency
Authors: Hidaka Soichiro , Kodama Kazuya , Maruyama Katsumi , Hashizume Hiromichi
Published: January 2004

Despite the increasing importance of control systems software, its development is quite difficult. To facilitate programming of control system software, we are developing an adaptable and extensible OS. This OS is characterized by a microkernel and multiserver: each server runs in protected mode, can drive hardware, and is added/extended/deleted with ease. This OS structure facilitates programming. Large intertask messaging overhead is anticipated in this scheme, but our implementation demonstrated good efficiency and maintainability. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(5): 20–28, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10163
Finite‐difference time‐domain analysis of ultrashort laser pulse propagation in a fiber with nonlinear effects
Authors: Nakamura Shinki , Koyamada Yahei , Karasawa Naoki , Sone Hiroyasu , Morita Ryuji , Yamashita Mikio
Published: January 2004

As a method of analyzing the nonlinear propagation of light, the Sellmeier equation for fused silica with three resonant frequencies is used and a finite‐difference time‐domain method taking the Raman response into account is proposed. The numerical results are compared with experimental results for optical pulses with a pulse width of 12 fs passing through a fused silica fiber. By this method of analysis, the numerical results are compared with those obtained by the conventional split‐step Fourier method and it is found that these results are closer to the experimental results. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(5): 1–10, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10166
Fabrication and characterization of alternately multilayered films consisting of organic ultrathin layer using self‐assembly and spin‐coating method
Authors: Nishimura Haruka , Iizuka Masaaki , Kuniyoshi Shigekazu , Nakamura Masakazu , Kudo Kazuhiro , Tanaka Kuniaki
Published: January 2004

Alternately multilayered films consisting of organic ultrathin layers with copper phthalocyanine tetrasulfonic acid tetrasodium salt (CuPcSAS) and polyaniline (PA) were fabricated by a self‐organized spin coating method. By observation with an atomic force microscope and measurement of the adsorption isotherm characteristics and temporal adsorption characteristics, it is found that each layer is sufficiently thin and flat and consists of a densely adsorbed monomolecular film. Also, the CuPcSAS monomolecular film exhibits semiconductor characteristics. Depending on the fabrication conditions, the conductivity of the CuPcSAS/PA ultrathin film alternating structure varies over four orders of magnitude. Applications to organic integrated circuits taking advantage of these characteristics are expected. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(2): 18–25, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10124
Electrically wavelength tunable laser based on one‐dimensional structure with liquid crystal defect layer
Authors: Ozaki Ryotaro , Matsui Tatsunosuke , Ozaki Masanori , Yoshino Katsumi
Published: January 2004

The localized state in a one‐dimensional photonic crystal having a liquid crystal defect layer can be controlled by applying a voltage. We used the light confinement effect of the photonic crystal and the shift in the localized state wavelength due to the introduction of a liquid crystal defect layer and tried to control the laser emission by optical pumping of the one‐dimensional photonic crystal having a liquid crystal defect layer and control the lasing wavelength upon applying an electric field. First, we used a dielectric multilayer of periodically stacked TiO2 and SiO2 layers as the one‐dimensional photonic crystal, introduced a nematic liquid crystal having excellent responsiveness to an external electric field as the defect layer that disrupts the periodicity, and verified that the peak wavelength can be controlled by applying a voltage based on the localized state in the one‐dimensional photonic band. These results agreed well with the numerical analysis results. Furthermore, we excited the dye‐doped liquid crystal by a pulse laser and measured the laser emission from the localized state wavelength. In addition, the emission wavelength was successfully modulated upon applying electric field. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(2): 1–8, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10173
Extraction of stomach fold regions from abdominal X‐ray CT images using 3D top‐hat transformation
Authors: Watanabe Shigeto , Hasegawa Jun‐ichi , Mekada Yoshito , Mori Kensaku , Nawano Shigeru
Published: January 2004

This paper presents a method for extracting stomach wall fold regions from abdominal X‐ray CT images using three‐dimensional morphology operations. The phenomenon of stomach wall folds concentrating in the direction of lesions is observed in over 60% of stomach cancer patients. Thus, the running pattern of stomach wall folds is an important clue in diagnosing stomach cancer. The method proposed in this paper is composed of three steps of preliminary processing, fold enhancement, and fold extraction and uses three‐dimensional top‐hat transformation which is a kind of light‐dense morphology operations in the enhancement step. Better results than those obtained in the past have been obtained by applying the proposed procedure to nine cases of actual CT images. In addition, effects of differences in imaging environments on the extraction results have been studied in samples in which the body positions during imaging and the amounts of the foaming medium administered orally had been varied. The results obtained provide important findings on the possibility of diagnosing stomach cancer using three‐dimensional CT images. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(2): 37–46, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10214
A security protocol intended to ease QoS management in IP networks
Authors: Shiraishi Yoshiaki , Fukuta Youji , Morii Masakatu
Published: January 2004

Many research projects and implementations related to QoS (Quality of Service) management technologies for providing stable network services have been undertaken. To perform QoS management, traffic classes are required. Generally, traffic is classified by setting priorities for packets, and the methods of setting those priorities include passive admission control in which clients set priorities and active admission control in which network edge routers check traffic and set priorities. To perform active admission control, identification information such as a TCP or UDP header must be inspected. However, with existing security protocols such as ESP (Encapsulating Security Payload) or SSH (Secure Shell), these kinds of information cannot be inspected because they are encrypted. Based on the point of view that active admission control should be performed to simplify QoS management of IP networks, the authors of this paper propose a security protocol named ESPQ (ESP considered QoS) for constructing active admission controllable packets and investigate the stability of that protocol. They also perform implementation experiments to show that existing control equipment such as routers can perform QoS management of ESPQ packets. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(2): 47–58, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10215
Matching of 3D tree structures using association graphs
Authors: Park Yongsup , Kitaoka Hiroko , Sato Yoshinobu , Tamura Shinichi
Published: January 2004

Matching of tree structures is equivalent to the problem of searching for maximum cliques in tree association graphs. Pelillo and colleagues have recently proposed a method for searching for maximum weight cliques that gives weight to association graphs on the basis of similarities of the attributes of tree nodes. Here, the obtained maximum weight clique corresponds to the maximum similarity subtree isomorphism. This paper proposes a tree structure‐matching scheme using tree association graphs, as a general scheme for performing nonrigid body registration of tree structures in three‐dimensional medical images. Matching of tree structures of three‐dimensional medical images of bronchi, blood vessels, and the like must be capable of handling changes in body positions accompanying their changes as well as physiological changes due to breathing exercises etc. In addition, it needs to recognize topology errors of pseudo or false branches occurring during image processing. This study, as attributes of tree nodes, constructs similarities using body volume change rates extending over the parents, children and siblings, focusing on the positional relations of the nodes of the parents, children, and siblings. The similarities proposed are those having high general properties that can be applied to changes in positions and shapes that occur inside a body since they focus on their general properties. In addition, as a method for avoiding mismatches due to topology errors, changing the weights of neighboring edges on the basis of similarities is added. The proposed scheme has been confirmed to show a high correct solution rate or true positive fraction regardless of high degree changes in positions and shapes when applied to a bronchial model generated inside a computer. It has also been confirmed that mismatches due to topology errors occur at a very low rate with the proposed scheme. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(2): 59–72, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10216
Forecasting commercial paper rates
Authors: Lackman Conway , Carlson William , Varick Celia
Published: January 2004

A model previously developed by Lackman (C. L. Lackman, Forecasting commercial paper rates. Journal of Business Finance and Accounting 15 (1988) 499–524) for the period 1960 to 1985 is updated to include the 1990s and incorporate statistical techniques relating to tests for stationary conditions not available in 1988. As in the previous model, the demand for commercial paper by each institution (Households (HH), Life Insurance Companies (LIC), Non‐Financial Corporations (CRP) and Finance Corporations (FC)) and the total demand is simulated. Simulations of the commercial paper rate are also generated—using just the demand equations (total supply exogenous) and then employing the entire model (supply endogenous) to determine the rate. Simulation periods are from 1960:2 to 2001:4 for all demand simulations.

The dynamic simulation of the total demand for commercial paper performs well. The resulting root mean square error, 3.485, compares favourably with the Federal Reserve Boston–Massachusetts Institute of Technology (FRB–MIT) estimate of the commercial paper rate (deLeeuw and Granlich, 1968). Copyright © 2004 John Wiley & Sons, Ltd.
Forecasts of the seasonal fractional integrated series
Authors: Darné Olivier , Guiraud Vivien , Terraza Michel
Published: January 2004

We study the probability of rejecting the seasonal unit root tests developed by Hylleberg et al. when they are applied to fractionally integrated seasonal time series. We find that these tests have quite low power and that they lead to a risk of over‐differencing. The forecasting performance of fractionally integrated seasonal models is also examined. This approach is compared with the traditional approaches from Box–Jenkins methodology, and the HEGY‐type test procedure. Forecasting results obtained from simulated series and quarterly economic time series show that the fractional approach improves the forecasting accuracy with regard to the other approaches. Copyright © 2004 John Wiley & Sons, Ltd.
Testing for association with a case‐parents design in the presence of genotyping errors
Authors: Morris Richard W. , Kaplan Norman L.
Published: January 2004

Genotyping errors can create a problem for the analysis of case‐parents data because some families will exhibit genotypes that are inconsistent with Mendelian inheritance. The problem with correcting Mendelian inconsistent genotype errors by regenotyping or removing families in which they occur is that the remaining unidentified genotype errors can produce excess type I (false positive) error for some family‐based tests for association. We address this problem by developing a likelihood ratio test (LRT) for association in a case‐parents design that incorporates nuisance parameters for a general genotype error model. We extend the likelihood approach for a single SNP to include short haplotypes consisting of 2 or 3 SNPs. The extension to haplotypes is based on assumptions of random mating, multiplicative penetrances, and at most a single genotype error per family. For a single SNP, we found, using Monte Carlo simulation, that type I error rate can be controlled for a number of genotype error models at different error rates. Simulation results suggest the same is true for 2 and 3 SNPs. In all cases, power declined with increasing genotyping error rates. In the absence of genotyping errors, power was similar whether nuisance parameters for genotype error were included in the LRT or not. The LRT developed here does not require prior specification of a particular model for genotype errors and it can be readily computed using the EM algorithm. Consequently, this test may be generally useful as a test of association with case‐parents data in which Mendelian inconsistent families are observed. Genet Epidemiol 26:142–154, 2004. Published 2004 Wiley‐Liss, Inc.
IL10 gene polymorphisms are associated with asthma phenotypes in children
Authors: Lyon Helen , Lange Christoph , Lake Stephen , Silverman Edwin K. , Randolph Adrienne G. , Kwiatkowski David , Raby Benjamin A. , Lazarus Ross , Weiland Katy M. , Laird Nan , Weiss Scott T.
Published: January 2004

IL10 is an anti‐inflammatory cytokine that has been found to have lower production in macrophages and mononuclear cells from asthmatics. Since reduced IL10 levels may influence the severity of asthma phenotypes, we examined IL10 single‐nucleotide polymorphisms (SNPs) for association with asthma severity and allergy phenotypes as quantitative traits. Utilizing DNA samples from 518 Caucasian asthmatic children from the Childhood Asthma Management Program (CAMP) and their parents, we genotyped six IL10 SNPs: 3 in the promoter, 2 in introns, and one in the 3′ UTR. Using family‐based association tests, each SNP was tested for association with asthma and allergy phenotypes individually. Population‐based association analysis was performed with each SNP locus, the promoter haplotypes and the 6‐loci haplotypes. The 3′ UTR SNP was significantly associated with FEV1 as a percent of predicted (FEV1PP) (P=0.0002) in both the family and population analyses. The promoter haplotype GCC was positively associated with IgE levels and FEV1PP (P=0.007 and 0.012, respectively). The promoter haplotype ATA was negatively associated with lnPC20 and FEV1PP (P=0.008 and 0.043, respectively). Polymorphisms in IL10 are associated with asthma phenotypes in this cohort. Further studies of variation in the IL10 gene may help elucidate the mechanism of asthma development in children. Genet Epidemiol 26:155–165, 2004. © 2004 Wiley‐Liss, Inc.
Gamma regression improves Haseman‐Elston and variance components linkage analysis for sib‐pairs
Authors: Barber Mathew J. , Cordell Heather J. , MacGregor Alex J. , Andrew Toby
Published: January 2004

Existing standard methods of linkage analysis for quantitative phenotypes rest on the assumptions of either ordinary least squares (Haseman and Elston [1972] Behav. Genet. 2:3–19; Sham and Purcell [2001] Am. J. Hum. Genet. 68:1527–1532) or phenotypic normality (Almasy and Blangero [1998] Am. J. Hum. Genet. 68:1198–1199; Kruglyak and Lander [1995] Am. J. Hum. Genet. 57:439–454). The limitations of both these methods lie in the specification of the error distribution in the respective regression analyses. In ordinary least squares regression, the residual distribution is misspecified as being independent of the mean level. Using variance components and assuming phenotypic normality, the dependency on the mean level is correctly specified, but the remaining residual coefficient of variation is constrained a priori. Here it is shown that these limitations can be addressed (for a sample of unselected sib‐pairs) using a generalized linear model based on the gamma distribution, which can be readily implemented in any standard statistical software package. The generalized linear model approach can emulate variance components when phenotypic multivariate normality is assumed (Almasy and Blangero [1998] Am. J. Hum Genet. 68: 1198–1211) and is therefore more powerful than ordinary least squares, but has the added advantage of being robust to deviations from multivariate normality and provides (often overlooked) model‐fit diagnostics for linkage analysis. Genet Epidemiol 26:97–107, 2004. © 2004 Wiley‐Liss, Inc.
Power of direct vs. indirect haplotyping in association studies
Authors: Thomas Stuart , Porteous David , Visscher Peter M.
Published: January 2004

Haplotype analysis is essential to studies of the genetic factors underlying human disease, but requires a large sample size of phase‐known data. Recently, directly haplotyping individuals was suggested as a means of maximizing the phase‐known data from a sample. Haplotyping, however, is much more labor‐intensive than indirectly inferring haplotypes from genotypes (genotyping). This study uses simulations to compare the power of each methodology to detect associations between a haplotype and a trait or disease locus under conditions of varying linkage disequilibrium. The relative power of haplotyping over genotyping in association studies increases with decreasing sample size, decreasing linkage disequilibrium, decreasing numbers of marker loci, and decreasing numbers of different haplotypes. In addition, the frequency of the haplotype of interest and the magnitude of its association with the disease affect the power. From a cost‐benefit standpoint, genotyping would be favored with large multiplicative risks (relative risk of haplotype >2.5). If case numbers are limiting rather than cost, haplotyping would maximize the information obtained. At small haplotype frequencies (e.g., <0.05), haplotyping is relatively more efficient, but there is little absolute power to detect associations under either methodology. Given the much larger laboratory resources required for direct haplotyping, genotyping would probably be favored under most conditions, but this must be balanced against the unit costs associated with recruitment and phenotyping. In the context of multipurpose, prospective cohort studies (e.g., the UK Biobank study), there may be a general value in establishing a series of directly haplotyped individuals to serve as controls for a number of alternative studies.Genet Epidemiol26:116–124, 2004. © 2004 Wiley‐Liss, Inc.
A trisomic transmission disequilibrium test
Authors: Xu Zhiying , Kerstann Kimberly F. , Sherman Stephanie L. , Chakravarti Aravinda , Feingold Eleanor
Published: January 2004

Certain congenital disorders that are rare in the general population are quite common in individuals with trisomic conditions. For example, complete atrioventricular septal defect occurs in about 20% of individuals with Down syndrome, an approximately 500‐fold increase in risk as compared to individuals without Down syndrome. Genetic variation on the chromosome involved in the trisomy may affect susceptibility to these trisomy‐specific disorders. That is, increased dosage of a variant may be directly involved in increasing the risk of a disorder, or it may be indirectly involved by causing up‐ or downregulation of other genes. As in standard disomic gene‐mapping, one can search for genes using linkage or association methods. Within association methods, one can consider case‐control methods or family‐based control methods such as the transmission disequilibrium test (TDT). Most gene‐mapping methods need to be substantially redesigned for use with trisomic data. In this paper, we present a “trisomic TDT”, a statistical method of testing for nonrandom transmission of alleles from parents to trisomic children. We demonstrate the method on a dataset of parent‐child trios in which the child has Down syndrome. Genet Epidemiol 26:125–131, 2004. © 2004 Wiley‐Liss, Inc.