bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of ampullary and colorectal malignancies
Authors: Das Ananya , Neugut Alfred I. , Cooper Gregory S. , Chak Amitabh
Published: January 2004

BACKGROUND

Because of the similarities in terms of carcinogenesis and natural history between cancer of the ampulla of Vater and colorectal cancer, the authors examined whether ampullary and colorectal malignancies occur in the same individuals at increased rates.

METHODS

We used data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute for the period from January 1973 through December 1999. Person‐years of follow‐up for patients with ampullary (or colorectal) cancer were used to calculate the expected number of cases of colorectal (or ampullary) cancer as a second primary malignancy. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were calculated using Byar limits and assuming a Poisson distribution.

RESULTS

The authors identified 2043 white patients with ampullary cancer who were included in the SEER registry between 1973 and 1999. Over an aggregate 5674 person‐years of follow‐up, 30 patients, compared with an expected 14, developed colorectal cancer, yielding an overall SIR of 2.14 (95% CI, 1.45–3.06). Similarly, 57 of 262,066 white patients with colorectal cancer developed ampullary cancer over an aggregate 1,270,255 person‐years of follow‐up, yielding an SIR of 2.18 (95% CI, 1.69–2.85).

CONCLUSIONS

Patients with ampullary cancer are at increased risk for a second primary colorectal malignancy, and patients with colorectal cancer are at increased risk for a second primary ampullary malignancy. These findings suggest that ampullary and colorectal malignancies share common environmental and/or genetic risk factors. Cancer 2004. © 2003 American Cancer Society.
Gamma radiation sensitivity and risk of malignant and benign salivary gland tumors
Authors: Zheng Rong , Wang Li‐E , Bondy Melissa L. , Wei Qingyi , Sturgis Erich M.
Published: January 2004

BACKGROUND

The salivary gland is a highly radiosensitive organ. Exposure to gamma radiation is a risk factor for both malignant (MSTs) and benign salivary gland tumors (BSTs), but the exact mechanisms remain unknown. The objectives of the current study were to determine whether gamma radiation–induced chromatid breaks increase the risk of MSTs and BSTs and whether there is any difference in risk between these two diseases.

METHODS

The authors performed a pilot case–control study of 57 patients with salivary gland diseases (45 patients with MSTs and 12 patients with BSTs) and 105 cancer‐free controls. Peripheral blood lymphocytes from these participants were cultured and exposed to gamma radiation (1.5 grays). Five hours later, metaphase spread slides were evaluated. The chromatid breaks in 50 well‐spread metaphase slides were counted to determine the average number of chromatid breaks per cell (b/c).

RESULTS

Multivariate logistic regression analyses revealed that gamma radiation–induced b/c values greater than the median of the controls were a significant risk factor for salivary gland tumors (adjusted odds ratio [OR], 17.25; 95% confidence interval [CI], 4.92–60.49). The risk remained significant for MSTs (adjusted OR, 40.45; 95% CI, 5.27–310.17) but was of borderline significance for BSTs (adjusted OR, 4.73; 95% CI, 0.94–23.87) when these tumors were analyzed separately.

CONCLUSIONS

In the current study, high levels of chromatid breaks in lymphocytes induced by gamma irradiation were associated with an independent risk for MSTs and were likely to increase the risk of BSTs. However, larger studies are needed to verify these findings. Cancer 2004. © 2003 American Cancer Society.
Temozolomide in the treatment of recurrent malignant glioma
Authors: Chang Susan M. , Theodosopoulos Philip , Lamborn Kathleen , Malec Mary , Rabbitt Jane , Page Margaretta , Prados Michael D.
Published: January 2004

BACKGROUND

Options for chemotherapy at the time of recurrence in patients with malignant glioma are limited. The authors describe the efficacy and safety results of their institution's open‐label, compassionate‐use protocol of temozolomide for patients with recurrent malignant glioma.

METHODS

Patients with recurrent malignant glioma at any time during recurrence were treated with oral temozolomide at a dose pf 150 mg/m2 per day on a 5‐day schedule every 28 days. If this dose was tolerated, then escalation to 200 mg/m2 was allowed. Clinical evaluations and assessments of tumor response were performed every 2 months. All patients or their surrogates signed approved Institutional Review Board consent forms.

RESULTS

Among 213 patients who were treated, 33% had Grade 3 tumors, and 67% had Grade 4 tumors. The overall objective response rate was 16% in both of these patient groups; and an additional 51% and 30% of patients with Grade 3 and Grade 4 tumors, respectively, had stable disease as their best response. The 6‐month progression‐free survival rates were 41% and 18% for patients with Grade 3 and Grade 4 tumors, respectively. The median survival was 49 weeks for patients with Grade 3 tumors and 32 weeks for patients with Grade 4 tumors. The major toxicity was hematologic toxicity. In multivariate analysis, the Karnofsky performance score was a significant predictor of survival for patients with Grade 4 tumors.

CONCLUSIONS

Temozolomide was well tolerated in patients with recurrent malignant glioma and had modest efficacy, even at the time of multiple recurrences. Cancer 2004. © 2003 American Cancer Society.
Activity of interferon‐α and isotretinoin in patients with advanced, refractory lymphoid malignancies
Authors: Tsimberidou Apostolia‐Maria , Giles Francis , Romaguera Jorge , Duvic Madeleine , Kurzrock Razelle
Published: January 2004

BACKGROUND

Interferon‐α (IFN‐α) and retinoids have shown nonoverlapping toxicity and each has shown antitumor activity in patients with lymphoma. The aim of the current study was to assess the toxicity, safety, and efficacy of IFN‐α combined with isotretinoin in patients with advanced, refractory lymphoid malignancies.

METHODS

Adults with biopsy‐proven advanced lymphoid malignancy were treated. Patients with compromised bone marrow function (platelet counts as low as 30 × 109/L) were eligible. Treatment was comprised of IFN‐α at a starting daily dose of 3 mega units subcutaneously and isotretinoin orally starting at a dose of 1 mg/kg daily in 2 divided doses.

RESULTS

Forty‐four patients were evaluable. Their median age was 57 years (range, 18–82 years). Eighteen patients had advanced cutaneous T‐cell lymphoma, 6 patients had peripheral T‐cell lymphoma, 14 patients had Hodgkin disease, and 6 patients had a variety of other lymphoid malignancies. Patients with Hodgkin disease had received a median of 6 previous therapies (range, 3–12 therapies) and patients with other lymphoid malignancies had received a median of 4 previous therapies (range, 1–9 therapies). The median duration of treatment was 4 months (range, 0.25–38 months). The overall response rate was 38.6% (complete response in 5 patients [11.3%] and partial response in 12 patients [27.3%]). The median response duration was 3 months (range, 1–95+ months). The most common toxicities were low‐grade fever, flu‐like symptoms, and fatigue (IFN‐α effects); dry mouth and skin and hypertriglyceridemia (cis‐retinoic acid effects); and thrombocytopenia (which generally occurred in patients with low baseline platelet counts).

CONCLUSIONS

IFN‐α and isotretinoin combination therapy had antitumor activity and was well tolerated in heavily pretreated patients with lymphoid malignancies. Cancer 2004. © 2003 American Cancer Society.
Parallel proximal‐point algorithms for mixed finite element models of flow in the subsurface
Authors: Alduncin Gonzalo , Vera‐Guzmán Norberto
Published: January 2004

Parallel proximal‐point algorithms for mixed finite element models of flow in the subsurface are presented. The applied methodology corresponds to operator splitting and non‐overlapping domain decomposition methods, combined with resolvent or proximation characterizations and proximal‐point algorithms. In this manner, macro‐hybrid mixed finite element models are systematically derived, in general being globally non‐conforming on the basis of non‐matching grids. Also, iterative algorithms of the Uzawa penalty–duality type are produced, which are well‐conditioned and robust. These parallel iterative algorithms generalize optimization and augmented Lagrangian procedures, and can be interpreted as implicit and semi‐implicit numerical time marching schemes. Copyright © 2004 John Wiley & Sons, Ltd.
Third‐order methods for first‐order hyperbolic partial differential equations
Authors: Cheema T. A. , Taj M. S. A. , Twizell E. H.
Published: January 2004

In this paper numerical methods for solving first‐order hyperbolic partial differential equations are developed. These methods are developed by approximating the first‐order spatial derivative by third‐order finite‐difference approximations and a matrix exponential function by a third‐order rational approximation having distinct real poles. Then parallel algorithms are developed and tested on a sequential computer for an advection equation with constant coefficient and a non‐linear problem. Copyright © 2003 John Wiley & Sons, Ltd.
Treatment of Neumann boundaries in the complex variable boundary element method
Authors: Sato Kozo , Watanabe Yusuke
Published: January 2004

For potential flow, the complex variable boundary element method (CVBEM) is formulated in terms of the velocity potential Φ and the stream function Ψ. In actual flow problems, Φ and ∂Φ/∂n are given along Dirichlet and Neumann boundaries, respectively. In the CVBEM, the Neumann‐type condition ∂Φ/∂n is not directly handled, and, instead, Ψ is used to define Neumann boundaries. Owing to this discrepancy, numerical difficulties are raised along Neumann boundaries. The current study addresses two such difficulties: (1) multiple Neumann boundaries and (2) branch cuts across Neumann boundaries. The first problem is due to the fact that Ψ along multiple boundaries cannot be specified a priori, and the second problem is due to the discontinuous jump inherent in Ψ for sink/source singularities. To overcome these difficulties, a new formulation of the CVBEM to solve for the unknown Ψ values and a proper way of branch‐cut placement are proposed, and these techniques are verified against example problems. Copyright © 2004 John Wiley & Sons, Ltd.
Multi‐level fracture network model for coupled seepage and stress fields in rock mass
Authors: Junrui Chai , Shouyi Li , Yanqing Wu
Published: January 2004

It is one of the issues of subsurface water resource research to investigate the models for coupled seepage and stress fields in rock mass. The present models can be summarized as the three types of (equivalent) continuum model, the fracture network model and the double media model. In this paper, a new multi‐level fracture network model is proposed for coupled seepage and stress fields in rock mass. According to the scale and permeability, the ruptures, faults, fractures, joints and pores in rock mass are divided into four levels, i.e. the level‐1 real fracture network, the level‐2 random fracture network, the level‐3 equivalent continuum system and the level‐4 continuum system. The level‐1 real fracture network is composed of larger ruptures and faults, whose distribution, mechanical and hydro‐mechanical parameters can be determined from the real geological information. Based on the fractures measurement and statistics, the level‐2 random fracture network is simulated by means of Monte—Carlo technique. The level‐3 equivalent continuum system is established to reflect the overall behaviour of small joints by means of the theory of hydraulic conductivity tensor. The level‐4 continuum system is composed of pores in rock, whose behaviour can be represented by the homogeneous and isotropic parameters. These fracture networks of four levels are related to each other by water and energy balance. In fracture network of each level, the different interaction between seepage and stress is introduced to construct the multi‐level fracture network model for coupled seepage and stress fields in rock mass. An engineering example is also given to show the applicability of the proposed model. Copyright © 2004 John Wiley & Sons, Ltd.
Eigensolutions for factorable matrices of special patterns
Authors: Kaveh A. , Sayarinejad M. A.
Published: January 2004

The method developed for eigensolution for matrices of special structures in Kaveh and Sayarinejad (Commun. Numer. Meth. Engng 2003; 19: 125–136) is extended to a more general special form known as Form III. Efficient methods are presented for evaluating the eigenvalues and eigenvectors of these matrices. Copyright © 2004 John Wiley & Sons, Ltd.
Numerical analysis of boundary‐value problems for singularly perturbed differential‐difference equations: small shifts of mixed type with rapid oscillations
Authors: Kadalbajoo M. K. , Sharma K. K.
Published: January 2004

We study the boundary‐value problems for singularly perturbed differential‐difference equations with small shifts. Similar boundary‐value problems are associated with expected first‐exit time problems of the membrane potential in models for activity of neurons (SIAM J. Appl. Math. 1994; 54: 249–283; 1982; 42: 502–531; 1985; 45: 687–734) and in variational problems in control theory. In this paper, we present a numerical method to solve boundary‐value problems for a singularly perturbed differential‐difference equation of mixed type, i.e. which contains both type of terms having negative shifts as well as positive shifts, and consider the case in which the solution of the problem exhibits rapid oscillations. The stability and convergence analysis of the method is given. The effect of small shift on the oscillatory solution is shown by considering the numerical experiments. The numerical results for several test examples demonstrate the efficiency of the method. Copyright © 2004 John Wiley & Sons, Ltd.
Strip layer method for simulation of the three‐dimensional deformations of plate and strip rolling
Authors: Hong‐Min Liu , Dan Jin , Ying‐Rui Wang
Published: January 2004

A new method—the strip layer method (SLM) is used to simulate the three‐dimensional deformations of plate and strip rolling process. The rolling deformation zone is divided evenly into a number of layers along the altitudinal direction of plate or strip, every layer plate (strip) is divided into a number of streamline strip elements along metal flow traces, and the streamline strip elements are mapped onto the corresponding rectangle strip elements for analysis and computation. The longitudinal distribution model of the metal lateral displacement is constructed to be a quartic curve, its lateral distribution is expressed as the third‐power spline function, and its altitudinal distribution is fitted to be a parabolic curve. Based on the flow theory of plastic mechanics, the three‐dimensional deformations and stresses of the deformation zone are analysed and formulated. Compared with the streamline strip element method (SSEM), the strip layer method considers the uneven distributions of stresses and deformations along altitudinal direction, and realizes an accurate analysis and computation. The simulation examples indicate that the method and the model of this paper are in accord with facts, and provide a new reliable engineering‐computation method for a three‐dimensional mechanics simulation of plate and strip rolling process. Copyright © 2004 John Wiley & Sons, Ltd.
A parametric study on the natural frequencies of unidirectional composite conical springs
Authors: Yıldırım Vebil
Published: January 2004

This paper deals with the combined influences of the vibrational parameters chosen as the material types, number of active turns, helix pitch angle, minimum to maximum radii of the cylinder and maximum cylinder to wire diameters on the first six resonance frequencies of unidirectional composite conical helical springs with solid circle section and fixed–fixed ends. The transfer matrix method based on the distributed parameter model is used for the determination of the fundamental natural frequencies. The rotary inertia, the shear and axial deformation effects are taken into account in the solution based on the first‐order shear deformation theory. Variation of the natural frequencies with the chosen vibrational parameters is given in non‐dimensional graphical forms. Using these charts, a numerical prediction of the first six linear dimensional free vibration frequencies of composite conical springs and their upper and lower limits with respect to the geometrical and material properties of the spring can be made with a good approximation. Copyright © 2004 John Wiley & Sons, Ltd.
Stationary biharmonic maps from Rm into a Riemannian manifold
Authors: Wang Changyou
Published: January 2004

For m ≥ 5, we prove that a stationary extrinsic (or intrinsic, respectively) biharmonic map u ∈ W2,2(Ω, N) from Ω ⊂ Rm into a Riemnanian manifold N is smooth away from a closed set of (m − 4)‐dimensional Hausdorff measure zero. © 2003 Wiley Periodicals, Inc.
Adiabatic charge pumping in open quantum systems
Authors: Avron Joseph E. , Elgart Alexander , Graf Gian Michele , Sadun Lorenzo , Schnee Kai
Published: January 2004

We introduce a mathematical setup for charge transport in quantum pumps connected to a number of external leads. It is proved that under rather general assumption on the Hamiltonian describing the system, in the adiabatic limit, the current through the pump is given by a formula of Büttiker, Prêtre, and Thomas, relating it to the frozen S‐matrix and its time derivative. © 2004 Wiley Periodicals, Inc.
Polyhedral stability ‐ on the growth of flat crystal faces on small molecule and protein crystals
Authors: Nanev Chr. N.
Published: January 2004

The old standing problem of face morphology is discussed. A special emphasis is put on the macroscopically flat faces, appearing on small molecule crystals mostly during calm growth, under low supersaturations. As distinct, protein crystals are growing with macroscopically flat faces even under surprisingly high supersaturations. Explanations of these facts are suggested by considering the surface micro‐profile of crystal faces which growth is driven by screw dislocations. It is shown that, due to kinetic reasons, the tips of the growth hillocks and the valley between them have to be levelled to some extent (at least on a quasi‐atomic scale) under low enough supersaturations. The amplitude of the surface roughness has to be suppressed also due to the surface energy gain, especially under quasi‐equilibrium. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of alloying elements on the crystallization behaviour and on the properties of galvanized coatings
Authors: Vourlias G. , Pistofidis N. , Stergioudis G. , Tsipas D.
Published: January 2004

The influence of the alloying elements on the interface reactions of zinc coatings during the galvanization process was examined. These reactions affect the crystallization and the structure and properties of the outer layer of the coatings. Depending on the type and concentration of the alloying additions in the galvanizing bath differences were induced in the crystallization process of the Fe‐Zn phases. It was found that both the concentration and the distribution of the alloying elements played an important role in the growth of the phases. The formation of the phases and the distribution of the alloying elements in the coatings were determined using X‐Ray diffraction (XRD) and Scanning Electron Microscopy (SEM) associated with an Energy Dispersive X‐Ray Spectroscopy (EDS) analysis. Finally the behaviour of the galvanized coatings was examined under accelerated salt spray corrosion conditions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The relations of sintering conditions and microstructures of [Bi0.5(Na1‐x‐yKxLiy)0.5]TiO3 piezoelectric ceramics
Authors: Lin D. M. , Xiao D. Q. , Zhu J. G. , Yu P. , Yan H. J. , Li L. Z. , Zhang W.
Published: January 2004

Bismuth sodium titanate (abbreviated as BNT) based solid solution, [Bi0.5(Na1‐x‐yKxLiy)0.5]TiO3 (0 < x + y < 1) ceramics, was invented in our group. These ceramics, which are considered as new candidates for lead‐free piezoelectric materials, were prepared by conventional ceramic sintering technique. The results of X‐ray diffraction show that the ceramics possess a single perovskite phase. The relations of the sintering conditions and the microstructures of the ceramics were studied. It was found that the optimized sintering condition is at 1100‐1150 °C for 2‐3 h, the grains of the ceramics have very regular shape, and the grain size of the ceramics is in the range of 1.3‐2.2 μm. These ceramics with the compositions of high amount of K+ and low amount of Li+ have relatively large piezoelectric charge constant (d33), and can be put into practical applications. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Minerals successions crystallisation related to tunisian natural brines
Authors: M'nif A. , Rokbani R.
Published: January 2004

Natural brines sampled from Sebkhats in southern part of Tunisia are considered to be seawater‐type solutions. The equilibrium solubility of this kind of solutions might be described by the fivefold seawatertype system Na+, K+, Mg2+, Cl‐, SO42‐ // H2O. The crystallisation sequences of salts, observed under solar evaporation, of two different Tunisians brines is discussed. Very important differences between the foreseeable results, based on the Equilibrium Solubility Diagram at 25 °C, and the experimental ones are settled. An attempt to explain the differences, based on the so‐called “solar sequences” as well as the “solar diagram” of evaporation, is made. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetoresistance, voltage‐current characteristics, and Hall effect measurements of bulk MgB2 superconductors
Authors: Kayed T. S.
Published: January 2004

Bulk MgB2 samples were prepared from the commercially available powder (Alfa‐Aesar). One of the samples was used in measuring the transport properties by the DC four‐probe technique while the other was used in measuring Hall effect using the van‐der‐Pauw configuration. From the transport measurements, we noticed that the R‐T curves shift to lower temperatures under applied magnetic field without any observed enlargement of the transition width. Tc gradually decreases from 37 K at zero field to 32 K at B = 1.4 T. Our V‐I data were found to obey a power law expression V ∝ Iβ(T, B). The change of β with temperature and magnetic field was shown and discussed. RH is positive under positive applied magnetic field. The 1/ RH linear dependency on T, usually observed in high temperature superconductors, could not be observed in our case. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical, optical and photoconductive properties of Poly(dibenzo‐18‐crown‐6)
Authors: Qasrawi A. F. , Cihaner A. , Önal A. M.
Published: January 2004

To investigate the energy levels, absorption bands, band gap, dominant transport mechanisms, recombination mechanisms and the free carrier life time behavior of poly‐dibenzo‐18‐crown‐6, poly‐DB18C6, films, the dark electrical conductivity in the temperature range of 200‐550 K, the absorbance and photocurrent spectra, the photocurrent –illumination intensity and time dependence at 300 K were studied. The dark electrical conductivity measurements revealed the existence of three energy levels located at 0.93, 0.32 and 0.76 eV below the tails of the conduction band. The main transport mechanism in the dark was found to be due to the thermal excitation of charge carriers and the variable range hopping above and below 260 K, respectively. The photocurrent and absorbance spectra reflect a band gap of 3.9 eV. The photocurrent ‐illumination intensity dependence reflects the sublinear, linear and supralinear characters indicating the decrease, remaining constant and increase in the free electron life time that in turn show the bimolecular, strong and very strong recombination characters at the surface under the application of low, moderate and high illumination intensity, respectively. A response time of 25.6 s was calculated from the decay of Iph‐time dependence. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoconductivity in Tl4S3 layered single crystals
Authors: Ashraf I. M. , Elshaikh H. A. , Badr A. M.
Published: January 2004

Photoconductivity measurements are carried out in this work for single crystals of Tl4S3 compound by using both pulsed excitation (a.c) and steady state (a.c) methods in order to elucidate the nature of photoconductivity (PC) in this compound. Results are reported in the temperature range from 77 to 300 K, excitation intensity range from 1800 to 3300 Lux, applied voltage range from 8 to 14 V, and wavelength range from 840 to 1450 nm. Both of the ac‐photoconductivity (ac‐PC) and the spectral distribution of the photocurrent are studied at different values of light intensity, applied voltage and temperature. Dependencies of carrier lifetime on light intensity, applied voltage and temperature are also investigated as results of the ac‐PC measurements. By using the results of the dc‐photoconductivity (dc‐PC) measurements, the temperature dependence of the energy gap width is described. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of lattice defects in divalent lattices by incorporating trivalent ions in biominerals: An EPR study of Cr(III) in zinc(II) potassium phosphate hexahydrate
Authors: Anandalakshmi H. , Venkatesan R. , Sambasiva Rao P.
Published: January 2004

In order to understand the effect of charge compensating vacancies on the number, orientation and magnitude of D‐tensors, single crystal EPR measurements have been carried out with Cr(III) in zinc(II) potassium phosphate hexahydrate at room temperature. During crystal rotations, a maximum of 6/7 resonance lines or a minimum of 2 is noticed. Crystal rotations done in the three orthogonal planes have yielded spin Hamiltonian parameters for one site with: gxx=1.969, gyy= 1.995, gzz= 2.107; Dxx= 66.2 mT; Dyy= 91.7 mT, and Dzz=‐157.9 mT. The powder EPR spectrum indicates a very broad line at g = 8, without any extra resonances from 0 to 650 mT both at room temperature and 77 K. The reason may be that due to large zero field splitting, the resonance at g = 2 is shifted to g = 8 position and the other resonances are below 0 or above 650 mT. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of the crystal structures of 1,3‐di‐tert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazasilol‐2‐ylidene and 1,3‐di‐tert‐butyl‐2,2‐dichloro‐1,3‐diaza‐2‐sila‐4‐cyclopentene
Authors: Becker J. S. , Staples R. J. , Gordon R. G.
Published: January 2004

The crystal structures of the title compounds, 1,3‐di‐tert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazasilol‐2‐ylidene, C10H20N2Si (1) and 1,3‐di‐tert‐butyl‐2,2‐dichloro‐1,3‐diaza‐2‐sila‐4‐cyclopentene, C10H20N2SiCl2 (3) were solved and are reported. Compound (1) crystallized in space group P mmn and each molecule has a mirror plane, which bisects the C‐C backbone of the N‐C‐C‐N framework. Compound (1) was also found to have a 2‐fold twin component. In compound (3) the space group P 21/m results with the mirror plane passing through the N‐C‐C‐N backbone. We compare these structures with the gas phase determination previously reported for (1) and the incomplete single crystal data for (3). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Differences in the embryonic expression patterns of mouse Foxf1 and ‐2 match their distinct mutant phenotypes
Authors: Ormestad Mattias , Astorga Jeanette , Carlsson Peter
Published: January 2004

Murine genes encoding the forkhead transcription factors Foxf1 and ‐2 are both expressed in derivatives of the splanchnic mesoderm, i.e., the mesenchyme of organs derived from the primitive gut. In addition, Foxf2 is also expressed in limbs and the central nervous system. Targeted mutagenesis of Foxf1 and ‐2 suggests that Foxf1 is the more important of the two mammalian FoxF genes with early embryonic lethality of null embryos and a haploinsufficiency phenotype affecting foregut‐derived organs. In contrast, the only reported defect in Foxf2 null embryos is cleft palate. To investigate if the differences in mutant phenotype can be attributed to nonoverlapping expression patterns or if distinct functions of the encoded proteins have to be inferred, we analyzed the early embryonic expression of Foxf2 and compared it with that of the better investigated Foxf1. We find that in the early embryo, Foxf1 is completely dominating—in terms of expression—in extraembryonic and lateral plate mesoderm, consistent with the malformations and early lethality of Foxf1 null mutants. Along the developing gut, Foxf1 is highly expressed throughout, whereas Foxf2 expression is concentrated to the posterior part—fitting the foregut haploinsufficiency phenotypes of Foxf1 mutants. Foxf2, on the other hand, is more prominent than Foxf1 in mesenchyme around the oral cavity, as would be predicted from the cleft palate phenotype. The differences in expression pattern also highlight areas where defects should be sought for in the Foxf2 mutant, for example limbs, the posterior gut, genitalia, and derivatives of the neural crest mesenchyme. Developmental Dynamics 229:328–333, 2004 © 2003 Wiley‐Liss, Inc.
Amphibian cardiac troponin I gene's organization, developmental expression, and regulatory properties are different from its mammalian homologue
Authors: Warkman Andrew S. , Atkinson Burr G.
Published: January 2004

In mammals, the expression of the troponin I‐slow (TnIs) isoform is predominant in the heart during embryogenesis and, shortly after birth, is replaced by the cardiac‐specific isoform, TnIc; a developmental switch thought to be mediated by thyroid hormone. Whereas, in Xenopus, TnIc is expressed at the onset of heart formation and is the only TnI isoform expressed in the heart. Herein, we demonstrate that the expression patterns of these genes appear to be common within the anuran lineage and, unlike their mammalian counterparts, are not affected by thyroid hormone. To elucidate the regulatory mechanism(s) governing the expression of the amphibian TnIc gene, we characterized the TnIc gene from Rana catesbeiana and used its 5′‐flanking region to drive expression of green fluorescent protein in the Xenopus transgenic system. Our results demonstrate that a 300‐bp minimal promoter containing intact GATA and CArG‐box elements is sufficient to drive expression of this reporter gene in a pattern that mimics, both spatially and temporally, the expression of the endogenous Xenopus TnIc gene. Developmental Dynamics 229:275–288, 2004.© 2003 Wiley‐Liss, Inc.
Isolation and expression of the homeobox gene Gbx1 during mouse development
Authors: Rhinn Muriel , Lun Klaus , Werner Michaela , Simeone Antonio , Brand Michael
Published: January 2004

In zebrafish, gbx1 and otx2 are among the earliest genes expressed in the neuroectoderm, dividing it into an anterior and a posterior domain with a common border that marks the midbrain–hindbrain boundary (MHB) primordium. Here, we describe the sequence and expression pattern of Gbx1 in mouse. The first transcripts are found at embryonic day 7.75 in the hindbrain. Later on, expression of Gbx1 is detectable in the hindbrain (rhombomeres 2 to 7), spinal cord, optic vesicles, and in the ventral telencephalon. In mouse, Gbx1 expression is not observed at the MHB as is the case during early zebrafish development. We suggest that an evolutionary switch occurred: in mouse Gbx2 is involved in the early specification of the MHB primordium, whereas in zebrafish, gbx1 is required instead of gbx2. Developmental Dynamics 229:334–339, 2004. © 2004 Wiley‐Liss, Inc.
Pilot morpholino screen in Xenopus tropicalis identifies a novel gene involved in head development
Authors: Kenwrick Sue , Amaya Enrique , Papalopulu Nancy
Published: January 2004

The diploid frog X. tropicalis has recently been adopted as a model genetic system, but loss‐of‐function screens in Xenopus have not yet been performed. We have undertaken a pilot functional knockdown screen in X. tropicalis for genes involved in nervous system development by injecting antisense morpholino (MO) oligos directed against X. tropicalis mRNAs. Twenty‐six genes with primary expression in the nervous system were selected as targets based on an expression screen previously conducted in X. laevis. Reproducible phenotypes were observed for six and for four of these, a second MO gave a similar result. One of these genes encodes a novel protein with previously unknown function. Knocking down this gene, designated pinhead, results in severe microcephaly, whereas, overexpression results in macrocephaly. Together with the early embryonic expression in the anterior neural plate, these data indicate that pinhead is a novel gene involved in controlling head development. Developmental Dynamics 289–299, 2004. © 2003 Wiley‐Liss, Inc.
Identification of the mammary line in mouse by Wnt10b expression
Authors: Veltmaat Jacqueline M. , Van Veelen Wendy , Thiery Jean Paul , Bellusci Saverio
Published: January 2004

Mammogenesis in rabbit, rat, and human begins with the formation of an elevated ectodermal ridge in the embryo. Attempts to demonstrate a morphologically or histologically equivalent mammary line in the mouse have yielded controversial results. We show here that a mammary line exists in the mouse embryo at embryonic day (E) 11.25 as a concise line of Wnt10b expression and a broader band of Wnt6 expression in the surface ectoderm, between the subaxillary and suprainguinal region of each flank. Additional streaks of Wnt10b expression in the axillary and inguinal region join the mammary line on the flank slightly later. Expression of Wnt10b and Wnt6 becomes restricted to the placodes within 1.5 days. The ectoderm of the mammary line is organized as a pseudostratified epithelium connecting the developing mammary placodes at around E11.5, whereas all other surface ectoderm is single‐layered. Thus, the mammary line expressing Wnt10b defines a distinct ectodermal region that we consider the equivalent of the ectodermal ridge in, for example, rabbit. To date, the formation of the mammary line expressing Wnt10b is the earliest discernible ectodermal event in murine embryonic mammary gland development. Developmental Dynamics 229:349–356, 2004. © 2004 Wiley‐Liss, Inc.
Embryonic myogenesis pathways in muscle regeneration
Authors: Zhao Po , Hoffman Eric P.
Published: January 2004

Embryonic myogenesis involves the staged induction of myogenic regulatory factors and positional cues that dictate cell determination, proliferation, and differentiation into adult muscle. Muscle is able to regenerate after damage, and muscle regeneration is generally thought to recapitulate myogenesis during embryogenesis. There has been considerable progress in the delineation of myogenesis pathways during embryogenesis, but it is not known whether the same signaling pathways are relevant to muscle regeneration in adults. Here, we defined the subset of embryogenesis pathways induced in muscle regeneration using a 27 time‐point in vivo muscle regeneration series. The embryonic Wnt (Wnt1, 3a, 7a, 11), Shh pathway, and the BMP (BMP2, 4, 7) pathway were not induced during muscle regeneration. Moreover, antagonists of Wnt signaling, sFRP1, sFRP2, and sFRP4 (secreted frizzled‐related proteins) were significantly up‐regulated, suggesting active inhibition of the Wnt pathway. The pro‐differentiation FGFR4 pathway was transiently expressed at day 3, commensurate with expression of MyoD, Myogenin, Myf5, and Pax7. Protein verification studies showed fibroblast growth factor receptor 4 (FGFR4) protein to be strongly expressed in differentiating myoblasts and newly formed myotubes. We present evidence that FGF6 is likely the key ligand for FGFR4 during muscle regeneration, and further suggest that FGF6 is released from necrotic myofibers where it is then sequestered by basal laminae. We also confirmed activation of Notch1 in the regenerating muscle. Finally, known MyoD coactivators (MEF2A, p/CIP, TCF12) and repressors (Twist, Id2) were strongly induced at appropriate time points. Taken together, our results suggest that embryonic positional signals (Wnt, Shh, and BMP) are not induced in postnatal muscle regeneration, whereas cell‐autonomous factors (Pax7, MRFs, FGFR4) involving muscle precursor proliferation and differentiation are recapitulated by muscle regeneration. Developmental Dynamics 229:380–392, 2004. © 2004 Wiley‐Liss, Inc.
Ror2 knockout mouse as a model for the developmental pathology of autosomal recessive Robinow syndrome
Authors: Schwabe Georg C. , Trepczik Britta , Süring Kathrin , Brieske Norbert , Tucker Abigail S. , Sharpe Paul T. , Minami Yasuhiro , Mundlos Stefan
Published: January 2004

Robinow syndrome (RS) is a human dwarfism syndrome characterized by mesomelic limb shortening, vertebral and craniofacial malformations and small external genitals. We have analyzed Ror2‐/‐ mice as a model for the developmental pathology of RS. Our results demonstrate that vertebral malformations in Ror2‐/‐ mice are due to reductions in the presomitic mesoderm and defects in somitogenesis. Mesomelic limb shortening in Ror2‐/‐ mice is a consequence of perturbed chondrocyte differentiation. Moreover, we show that the craniofacial phenotype is caused by a midline outgrowth defect. Ror2 expression in the genital tubercle and its reduced size in Ror2‐/‐ mice makes it likely that Ror2 is involved in genital development. In conclusion, our findings suggest that Ror2 is essential at multiple sites during development. The Ror2‐/‐ mouse provides a suitable model that may help to explain many of the underlying developmental malformations in individuals with Robinow syndrome. Developmental Dynamics 229:400–410, 2004, © 2004 Wiley‐Liss, Inc.
A high‐speed HMM VLSI module with block parallel processing
Authors: Yoshizawa Shingo , Miyanaga Yoshikazu , Yoshida Norinobu
Published: January 2004

This paper considers the continuous distribution HMM and discusses speed improvement by parallel processing and VLSI design, aiming at the realization of a high‐speed speech recognition LSI. The continuous distribution HMM has high recognition performance. But a large amount of computation is required for the calculation of the output probability, and speed improvement is highly desirable. Regarding speed improvement of the output probability calculation, this paper proposes blockwise parallel processing and an architecture for performance. The minimum optimal bit width is investigated for recognition by fixed‐point operations. Based on the proposed architecture, VLSI design for an HMM is performed and the result is evaluated. It is shown that the proposed architecture has sufficient power to construct a recognition system that can respond in real time, requiring 3 ms for the recognition processing of 100 words. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(5): 12–23, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10099
Simplified training algorithm for hierarchical hidden Markov models
Authors: Ueda Nobuhisa , Sato Taisuke
Published: January 2004

This paper considers an extension of the hidden Markov model, called the hierarchical hidden Markov model, and proposes an EM algorithm and an approximate algorithm. The EM algorithm proposed in this paper differs from the existing training algorithm, which is called the Baum–Welch algorithm, and guarantees that the likelihood is always increased by updating the parameters. The approximate algorithm has the advantage that it can be applied to problems in which observation of the training sentence and training of the parameters proceed in parallel. These algorithms and their derivations are simplified, compared to the existing training algorithm, by using stochastic context‐free grammar. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(5): 59–69, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10172
Robust scheme of an indirect MRACS system taking into account the presence of deterministic disturbances
Authors: Suzuki Yoshiaki , Suzuki Takashi , Itamiya Keietsu
Published: January 2004

This paper presents a method for the design of an indirect model reference adaptive control (MRAC) system for a plant with deterministic disturbances, robust to modeling errors due to unmodeled dynamics and observation noise. In the proposed method, the structure of the controller is determined on the basis of the internal model principle to reject the deterministic disturbance, and its parameters are adjusted by using the estimated plant parameters. Robustness to the modeling errors is ensured by the use of the adaptive law with a dead zone and a fixed compensator of integral type. The adaptive law prevents the adjustable parameters from drifting and the fixed compensator improves the control performance degraded by the use of the dead zone. Stability of the MRAC system is analyzed using the concept of the ℒ︁2δ norm and the Bellman–Gronwall lemma, based on the properties guaranteed by the adaptive law. Effectiveness of the proposed method is demonstrated by the simulation carried out for a plant with second‐order nominal part and a step disturbance. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 65–75, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10190
Calculation of the loss‐minimum configuration in the IEEJ local power system model
Authors: Hayashi Yasuhiro , Matsuki Junya , Kurihara Ikuo
Published: January 2004

In Japan, local power systems (77 kV) are served from the 275‐ or 154‐kV substations. For enhancement of power supply reliability, the transmission lines are connected to several substations, and the operational configuration is radial. The local power system's configuration is determined by connecting and disconnecting transmission lines so as to keep the radial structure and satisfy the operation constraints. When a local power system has a number of transmission lines, many configuration candidates occur. Recently, an IEEJ committee made a practical scale local system model (IEEJ Local System Model). Since the IEEJ Local System Model has 76 transmission lines, the total number of configuration candidates is 276 (approximately 7.5 × 1022). In this paper, the authors try to strictly obtain the loss‐minimum configuration under constraints such as substation capacity, line capacity, and radial structure in the IEEJ Local System Model. In order to obtain the optimal configuration, a new computation algorithm is proposed. In the proposed algorithm, the configuration determination problem is replaced as two combinatorial optimization problems based on the operational constraints [(1) substation capacity, (2) line capacity, and (3) radial structure]. One combinatorial optimization problem (subproblem 1) is to pick up all partial configurations so as to minimize total line loss under the substation capacity constraint. By using the enumeration method, subproblem 1 is solved. Subproblem 2 is solved by using the reduced ordered binary decision diagram (ROBDD). Since the proposed method is based on enumeration and Boolean function, the optimality of obtained solution is guaranteed. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 34–42, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10226
Insulation characteristics of SF6 gas for nonstandard impulse voltage polarity reversal pulse waveforms
Authors: Rokunohe Toshiaki , Suzuki Toshiyuki , Yamagiwa Tokio , Yuasa Sadayuki , Okabe Shigemitsu
Published: January 2004

Evaluation of insulation strength for lightning surge that actually enters into substations is important in estimating insulation reliability of gas‐insulated equipment. The standard lightning impulse voltage (1.2/50 µs) is used for factory tests. However, the actual lightning surge waveforms in substations are complex and are usually superimposed with various oscillations. Insulation characteristics of SF6 gas as a function of such complex voltages have not been sufficiently clarified.

This paper deals with gap breakdown characteristics in SF6 gas under submicrosecond pulses. Breakdown voltages are lower under a polarity reversal condition than under a monopolarity condition. The cause of this difference is discussed while observing discharge propagation using an image converter camera. The electrode size effect is also discussed. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 18–25, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10246
Development of a laser wavefront sensor for measurement of discharges in air
Authors: Fukuchi Tetsuo , Yamaguchi Yukihiro , Nayuki Takuya , Nemoto Koshichi , Uchino Kiichiro
Published: January 2004

A laser wavefront sensor of the Shack‐Hartmann type capable of simultaneous measurement at two wavelengths was constructed. The sensor uses a single optical path, and is suited for applications such as high‐voltage discharges in air, in which large insulation distances are necessary. The sensor was used to detect optical path differences due to an impulse discharge in air across a needle–plane electrode gap of gap length 17 mm. Optical path differences were measured at laser wavelengths of 532 and 1064 nm at 1.6 µs after insulation breakdown across the gap. From the difference in optical path differences at the two wavelengths, a line‐integrated electron density distribution in the direction perpendicular to the gap was obtained near the high‐voltage electrode. The distribution had a peak value of 1.4 × 1020m−2 and a full width at half maximum of 4.4 mm. Because of the coverage of a large observation area including the entire gap, the spatial resolution was 1.4 mm, which was inadequate to obtain the precise form of the electron density distribution. However, the results show the possibility of applying laser wavefront sensing to electron density measurement. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 10–17, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10247
Grain‐size dependence of absorption characteristics of the electromagnetic wave absorbers of ferrite‐SiO2 composites
Authors: Kusunoki Hiroki , Kondo Takatoshi , Hiraki Kiyohiro , Takada Kazushi , Yoshikado Shinzo
Published: January 2004

Grain‐size dependence of electromagnetic absorbing characteristics for composite materials made of Ni‐Zn ferrite and SiO2 was investigated using SiO2 with various grain sizes (29 µm, 30 nm, 12 nm, and 7 nm). The absorption characteristics of ferrite composites using SiO2 with an average grain size of 30, 12, or 7 nm were improved compared with those of ferrite composites using SiO2 with an average grain size of 29 µm in the low‐frequency region. Furthermore, the grain size dependence of the absorption characteristics for composite materials of Mn‐Zn ferrite with an average grain size of 130 nm and SiO2 with an average grain size of 29 µm was investigated. The absorbing center frequency shifted to a higher frequency region than that of Mn‐Zn ferrite. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 1–9, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10269
Access to 3‐Methyl‐4‐methylene‐N‐tosylpyrrolidine and 3,4‐DimethylN‐tosylpyrroline by Ruthenium‐Catalyzed Cascade Cycloisomerization/Isomerization Reactions
Authors: Özdemir Ismail , Çetinkaya Engin , Çetinkaya Bekir , Çiçek Metin , Sémeril David , Bruneau Christian , Dixneuf Pierre H.
Published: January 2004

New RuCl2(benzimidazole)(arene) complexes have been prepared. Upon reaction with 1,1‐diphenylprop‐2‐ynol they generate catalyst precursors which perform the cycloisomerization of diallyltosylamide into 3‐methyl‐4‐methylene‐N‐tosylpyrrolidine. The presence of N‐(2,4,6‐trimethylbenzyl)benzimidazole as ligand leads to a subsequent isomerization and gives the 3,4‐dimethyl‐N‐tosylpyrroline. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)