bluuebunny/crossref_metadata_2025 huggingface dataset:
Fast time behavior of the polarization filtering in anisotropically strained M ‐plane GaN films
Authors: Flissikowski T. , Misra P. , Brandt O. , Grahn H. T.
Published: January 2007

The dynamic behavior of the polarization filtering in M ‐plane GaN films is investigated by time‐resolved pump‐and‐probe spectroscopy. The reduced in‐plane crystal symmetry and the anisotropic in‐plane strain in M ‐plane GaN films lead to different absorption coefficients along the two principle in‐plane axes. The absorption can be selectively bleached by additional pumping with polarized light along one of these two axes. On an ultra‐fast timescale, the resulting pump‐and‐probe transients are governed by two different processes, namely the relaxation dynamics of holes in the two uppermost valence bands and the coherent coupling artifact. The recovery of the absorption is analyzed using the time symmetry of the coherent artifact and a rate‐equation model for carrier relaxation and redistribution in the valence bands. The analysis yields redistribution times below 1 ps and carrier recombination times of about 15 ps. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and optical characterization of III‐nitride air‐bridge photonic crystal with GaN quantum dots
Authors: Li Ning , Arita M. , Kako S. , Kitamura M. , Iwamoto S. , Arakawa Y.
Published: January 2007

We report the fabrication of III‐nitride air‐bridge photonic crystals with GaN quantum dots for the first time. Photonic crystals with various periodicities and airhole diameters were fabricated. Abrupt vertical profiles and high aspect ratio (∼3) were achieved with excellent reproducibility even to the structure with periodicity as small as 150 nm. The fabrication of air‐bridge structure utilizing photoelectrochemical etching of SiC was demonstrated. Strong photoluminescence enhancement by a factor of 5 was observed from GaN QDs embedded in the air‐bridge PC layer. This is due to the coupling of PL light with photonic bands above the light cone, thus results in the enhanced light extraction efficiency. These results will lead to the realization of high efficiency quantum dots based emitting devices in blue and ultraviolet range. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photonic circuits writing with UV pulsed laser
Authors: Kribich K. R. , Gatti S. , Jabbour J. , Pille G. , Calas S. , Mazingue T. , Etienne P. , Legros R. , Moreau Y.
Published: January 2007

Photonics technology is employed in a growing number of applications. Biological and chemical sensors (E. Udd, Fiber Optic Sensors: An Introduction for Engineers and Scientists, Wiley, New York, 1991 [1]) for health and environment demand an adaptable technology. Network development towards the end‐user requires more interconnecting components. Vision, lighting, data processing in hostile environment (spatial, military) need specific technologies. A flexible and low‐cost process using good quality material is necessary. The sol‐gel process is a chemical method to fabricate glasses at ambient pressure and moderate temperature. Hybrid materials (H.K. Schmidt et al., Proc. SPIE 3136, 220 (1997) [2]), mixing organic and inorganic parts, offer the advantages of polymer‐like materials and glasses. We report on a new hybrid sol‐gel technology to overcome the drawbacks of the formerly presented one (H. Krug, F. Teillantes, P.W. Oliviers, and H. Schmidt, Proc. SPIE 1758, 448 (1992) [3]). We present the material synthesis, an accurate and flexible fabrication process based on a pulsed UV laser lithography system and the characterisation of the optical waveguides and photonic circuits realised. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
M ‐plane GaN‐based dichroic photodetectors
Authors: Rivera C. , Misra P. , Pau J. L. , Muñoz E. , Brandt O. , Grahn H. T. , Ploog K. H.
Published: January 2007

The in‐plane asymmetry of M ‐plane GaN films was used to fabricate polarization‐sensitive photodetectors. The measured contrasts between the detected light polarized perpendicular and parallel to the c‐axis are as high as 7.25 at 363 nm for a 0.4 μm thick film. For other film thicknesses, the polarization‐sensitive bandwidth can be increased. At the same time, the position of the maximum contrast is also affected by the film thickness through a different strain state. Considerations for the detector design show that the film thickness affects both, the contrast and polarization‐sensitive bandwidth, through the absorption and the effect of the strain on the valence‐band splitting. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spatial mapping on surface light extraction from 2D photonic quasicrystals patterned GaN‐based light emitters
Authors: Zhang ZhenSheng , Zhang Bei , Dai Tao , Bao Kui , Liu Dan , Wang Xiao , Kang XiangNing , Xu Jun , Yu DaPeng , Zhu Xing
Published: January 2007

We report the observations of surface light extraction enhancement from two‐dimensional (2D) photonic crystal (PC) and Photonic Quasicrystal (PQC) patterns on electrical current injected GaN‐based light emitters. Spatial mapping of the surface extraction was acquired by a microscopic electrical luminescence setup and a scanning near‐field optical microscope (SNOM). Slight difference of mapping profile between twelve‐fold PQC and regular triangular PC was obtained. It is shown that 12PQC was more efficient for light extraction. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sol‐gel based YAG:Ce3+ powders for applications in LED devices
Authors: Potdevin A. , Chadeyron G. , Boyer D. , Mahiou R.
Published: January 2007

Luminescent Y3(1‐x)Al5O12:Ce3+3x (YAG: Ce3+) (x = 0.001 to 0.05), Lu2.97Al5O12:Ce3+0.03 (LuAG: Ce3+) and Y3‐0.03‐3yAl5O12:Ce3+0.03, Tb3y (YAG: Ce3+,Tb3+) (y = 0.1 and 0.2 phosphor powders have been successfully prepared by the sol‐gel route from alkoxide precursors. Purity of derived materials was investigated by X‐ray diffraction (XRD): Pure YAG phase was obtained without any intermediate whatever the Ce3+ doping rate between 0.1 and 5 mol% and LuAG phase was also effectively achieved.

Luminescent properties of samples have been recorded. Excitation spectra of YAG:Ce3+ crystallized powders have revealed a broad excitation band around 470 nm, which matches very well with GaN‐based blue LED. On the basis of the emission spectra study under blue excitation, the Ce3+ optimal concentration of powders has been determined. Eventually, effects of codoping by Tb3+ and substituting Y3+ by Lu3+ have been analysed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Imprint lithography advances in LED manufacturing
Authors: Hershey Robert , Doyle Gary , Jones Chris , LaBrake Dwayne , Miller Mike
Published: January 2007

Imprint lithography is a promising cost effect alternative to e‐beam and optical lithography for producing photonic crystals and other nano‐scale light extraction and beam directing elements for LEDs; however, there are several challenges that must be overcome before imprint lithography can be applied to typical LED substrates. This paper reviews progress made at Molecular Imprints Inc. (MII) in imprinting representative 3″ GaN on Sapphire substrates including methods for dealing with substrate non‐flatness, multi‐die imprint, and imprinting on warped and bowed substrates. The results of imprinting over typical GaN on Sapphire topography and common defects such as fall‐on particles and EPI defects is presented along with results on GaN wafers optimized for imprint lithography. Whole wafer thin template replication techniques are also discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and optical properties of blue LEDs with silica microsphere coating
Authors: Kusakabe K. , Funazaki S. , Okamoto K. , Nishizawa S. , Ohkawa K.
Published: January 2007

We report the enhancement of light extraction efficiency of InGaN‐based blue light emitting diodes by using a surface light‐scattering layer. A number of SiO2 microspheres embedded into a ZrO2 thin layer played a role of a light‐scattering medium. Coating the light‐scattering layer on device surface, the inter‐ ference fringes of electroluminescence (EL) spectra were eliminated and the EL intensity around 440–450 nm was increased by a factor of 1.3. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth behavior and optical properties of In‐rich InGaN quantum dots by metal‐organic chemical vapor deposition
Authors: Kim Hee Jin , Kwon Soon‐Yong , Kim Hyun Jin , Na Hyunseok , Shin Yoori , Lee Keon‐Hun , Kwak Ho‐Sang , Cho Yong Hoon , Yoon Jung Won , Cheong Hyeonsik , Yoon Euijoon
Published: January 2007

We successfully grew In‐rich In0.8Ga0.2N/GaN quantum dots (QDs) by metal‐organic chemical vapor deposition. We obtained uniform QDs with density of 1.3 x 1010/cm2 by optimizing growth conditions. Strong photoluminescence (PL) emission from In‐rich InGaN/GaN QDs was observed at room temperature and emission wavelength was varied from 404 nm to 454 nm depending on QD size. It is strongly suggested that QDs leads to higher radiative recombination efficiency from temperature‐dependent PL measurement. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deep ridge GaN cw‐laser diodes
Authors: Dennemarck J. , Tessarek C. , Figge S. , Hommel D.
Published: January 2007

The processing of homoepitaxial grown GaN based laser diodes by means of chemical assisted ion beam etching (CAIBE) is discussed. These laser diodes, emitting in the blue/UV spectral region, have been processed as buried ridge wave guide structures. Both, the influence of process parameters during etching such as the angle of incidence of the ions and gas fluxes as well as the impact of the ridge depth on the device performance will be analysed. Steep and smooth sidewalls of the ridge have been achieved by optimising the process parameters and by etching the ridge through the active region, cw‐lasing has been achieved. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homoepitaxial laser diodes emitting at 390 nm and the influence of substrate quality
Authors: Figge Stephan , Dennemarck Jens , Hommel Detlef
Published: January 2007

This paper deals with the homoepitaxial growth of laser diodes and the dependence on the substrate quality. We will present laser diodes emitting at 390 nm which are capable of cw‐operation. Lifetime measurements have been conducted and the degradation of the diodes will be discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of lattice‐mismatch induced built‐in strain on the valence band properties of wurtzite ZnO/Zn1–xMgxO quantum well heterostructures
Authors: Zitouni K. , Kadri A.
Published: January 2007

We present a theoretical study of the effects of lattice‐mismatch induced built‐in strain on the electronic properties of valence band states in wurtzite ZnO/Zn1–xMgxO Quantum Well (QW) heterostructures. In this purpose, a 6x6 k·p method has been used to incorporate the effects of strain and nonparabolicity. The energies corresponding to the transitions between conduction band (C), heavy hole (HH), light hole (LH) and crystal‐field split‐off hole (CH) bands have been calculated as a function of Mg composition and strain. We have also calculated the energy dispersions and wave functions of strained wurtzite ZnO. It is found that ZnO is always under a biaxial tensile strain, in the whole Mg composition range investigated (x < 40%). As a consequence, the light hole valence subband is shifted upwards with respect to the corresponding heavy hole valence subband, resulting in a reduction of ZnO direct band gap by almost 6% when x = 35%. This is found to result in turn in a significantly reduced in‐plane hole effective mass at the top of the valence band which is always LH‐like. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of thick GaN layers on c‐plane sapphire substrates using stress absorbing layer (SAL)
Authors: Goto H. , Lee S. W. , Kinomoto J. , Kim S. T. , Ko H. C. , Cho M. W. , Yao T.
Published: January 2007

We investigate the effects of inserting defective stress absorbing layer (SAL) in between sapphire substrate and thick GaN layer. A two‐step growth technique, in which GaN layers grow at different growth rates in each step, is adopted for growing high‐quality GaN layer (NL) at low growth rate and SAL at high growth rate by hydride vapor phase epitaxy (HVPE). SALs grown directly on c‐sapphire show hexagonal columnar shaped rough morphology with low crystalline quality. Nevertheless, strain in SAL is more relaxed compared with high quality NL. SAL contains majority of high‐quality layers and minority of highly defective regions. The highly defective regions are strongly in‐plane compressed by thermal stress and absorbs thermal stress. Overgrown NLs on SALs show lower residual strain compared to NL on NL sample. These results show that bending and microcracks can be suppressed in free‐standing GaN substrates by adopting SALs in GaN growth. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The quantum efficiency of green GaInN/GaN light emitting diodes
Authors: Zhao W. , Li Y. , Detchprohm T. , Wetzel C.
Published: January 2007

Energy efficient lighting can be achieved by help of high efficiency light emitting diodes (LEDs). Substantial performance gains are feasible in the green – 500–555 nm – spectral region by implementing proper design of the active region. Here we analyze external quantum efficiency of high performing LED dies as a function of current and temperature in order to formulate relevant optimization rules. Among a large sample set we identify traits that clearly correlate with respective device performance. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phonons in strained AlGaN/GaN superlattices
Authors: Darakchieva V. , Monemar B. , Paskova T. , Einfeldt S. , Hommel D. , Lourdudoss S.
Published: January 2007

Phonons in strained AlGaN/GaN superlattices (SLs) with constant periods but different Al composition have been studied using a combination of infrared spectroscopic ellipsometry and Raman scattering spectroscopy. The following SL modes were identified: i) AlGaN localized E 1(TO) modes identified for the first time and AlGaN localized A 1(LO) phonons; ii) GaN localized E 2, E 1(TO) and A 1(LO) phonons; iii) delocalized E 1(LO) phonons; iv) A 1(TO) phonon; v) two modes around 660 cm–1 and 594‐625 cm–1, respectively, not predicted by theory. The effects of strain and composition on the phonon frequencies were established and discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of GaN‐based electroluminescent devices on Al substrates and their application to red, green and blue pixels for flat‐panel displays
Authors: Sugimoto Koichi , Egawa Shinichi , Arai Masatoshi , Honda Tohru
Published: January 2007

GaN‐based thin‐film electroluminescent devices (TF‐ELDs) operating in the UV spectral region were fabricated on Al substrates. GaN films were deposited by compound‐source molecular beam epitaxy (CS‐MBE) technique. During the deposition, the cell temperature of the GaN compound source is one of the key factors for reducing the excess Ga in the films. The UV light emission (peak wavelength 375 nm) corresponding to the near‐band‐edge emission of hexagonal GaN was observed from GaN‐based TF‐ELDs. Furthermore, red, green and blue (RGB) lighting pixels were fabricated using UV GaN‐based TF‐ELDs in combination with RGB phosphors. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An electrospray membrane probe for the analysis of volatile and semi‐volatile organic compounds in water
Authors: VanHassel Emily , Bier Mark E.
Published: January 2007

A new membrane probe incorporating electrospray ionization (ESI) was designed, built and coupled to an ion trap mass spectrometer to detect low levels of semi‐volatile organic compounds (SVOCs) in water. Similar to other membrane introduction mass spectrometry (MIMS) systems, the probe contains a capillary polydimethylsiloxane (PDMS) membrane to allow for the preferential permeation of small molecules but, in contrast, the interface uses a liquid/membrane/liquid interface rather than liquid/membrane/gas. The ESI source allows the probe to be operated at atmospheric pressure in positive or negative ionization mode and the lack of fragmentation in ESI allows for the simultaneous screening of many analytes with high sensitivity. The interface allows for the addition of additives to both the external and the internal liquid mobile phases to selectively improve permeation and/or the ionization efficiency of various classes of compounds. Characterization of the probe with methanol as the internal mobile phase showed that the signal for aniline optimized at 60°C and an internal flow rate between 2–5 µL/min. The transfer of analyte through the membrane from water to methanol ensures a strong signal and robust electrospray for both positive and negative ion mode which is not typical when spraying pure water. Detection limits for aniline, pyridine and pentachlorophenol, and for the herbicides alachlor, atrazine, butachlor, metolachlor and simazine, were in the ppb to pptr range. Copyright © 2007 John Wiley & Sons, Ltd.
Resin‐packed nanoelectrospray in combination with video and mass spectrometry for the direct and real‐time molecular analysis of mast cells
Authors: Sirikatitham Anusak , Yamamoto Takahiro , Shimizu Masakazu , Hasegawa Tomomi , Tsuyama Naohiro , Masujima Tsutomu
Published: January 2007

A nano‐electrospray ionization (nanoESI) emitter for analysis of a biological solution was developed by packing a nanoESI needle with two types of resins for desalting and preconcentration of target molecules. Determination of secreted histamine and serotonin molecules in cell culture buffers was demonstrated using 5‐methyltryptamine as internal standard. The results showed good linearity of target signals in the concentration range from 0.25 to 50.0 ng/mL of histamine or serotonin. These molecules were monitored to be secreted by A23187 (calcium ionophore) stimulant in rat peritoneal mast cells. Using a combination of a video‐microscope and a mass spectrometer, we could visualize exocytotic moments and analyze secreted molecules by mass spectrometry simultaneously. Time‐dependent release of histamine and serotonin from activated mast cells showed that significant production of these molecules occurred and reached a maximal level at 15 min for serotonin and at 30 min for histamine, respectively. These results showed that this method allows the direct and timely analysis of secreted molecules in biological responses. Copyright © 2007 John Wiley & Sons, Ltd.
The venom of the snake genus Atheris contains a new class of peptides with clusters of histidine and glycine residues
Authors: Favreau Philippe , Cheneval Olivier , Menin Laure , Michalet Sophie , Gaertner Hubert , Principaud Franck , Thai Robert , Ménez André , Bulet Philippe , Stöcklin Reto
Published: January 2007

We investigated venoms from members of the genus Atheris (Serpentes, Viperidae), namely the rough scale bush viper (Atheris squamigera), the green bush viper (A. chlorechis) and the great lakes bush viper (A. nitschei), using mass spectrometry‐based strategies, relying on matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) and electrospray ionisation tandem mass spectrometry (ESI‐MS/MS) with de novo peptide sequencing. We discovered a set of novel peptides with masses in the 2–3 kDa range and containing poly‐His and poly‐Gly segments (pHpG). Complete primary structural elucidation and confirmation of two sequences by Edman degradation indicated the consensus sequence EDDH(9)GVG(10). Bioinformatic investigations in protein sequence databanks did not show relevant homology with known peptides or proteins. However, a more extensive investigation of data in nucleic acid databases revealed some similarities to the precursor sequences of bradykinin potentiating peptides (BPP) and C‐type natriuretic peptides (CNP), agents that are known to affect the cardiovascular system by acting on specific metalloproteases and receptors. The novel pHpG peptides found in Atheris venoms might also act on the cardiovascular system by inhibiting particular metalloproteases, which however remain to be identified. Copyright © 2007 John Wiley & Sons, Ltd.
High‐throughput direct‐infusion ion trap mass spectrometry: a new method for metabolomics
Authors: Koulman Albert , Tapper Brian A. , Fraser Karl , Cao Mingshu , Lane Geoffrey A. , Rasmussen Susanne
Published: January 2007

A fast method was developed to directly infuse raw plant extracts into a linear ion trap mass spectrometer, using the ion trap to isolate and fragment as many ions as possible from the extract. The full mass spectra can be analysed by multivariate statistics to determine discriminating ions, and the fragmentation data allows rapid classification or identification of these ions. The methodology was used to screen a wide range of strains of endophytic fungi in perennial ryegrass seeds for differences in metabolic profiles. The results show that this newly developed methodology is able to determine discriminating ions that can be present in very low concentrations. It also yielded sufficient fragmentation data to classify or identify the discriminating ions. Copyright © 2007 John Wiley & Sons, Ltd.
Photodissociation at 193 nm of some singly protonated peptides and proteins with m/z 2000–9000 using a tandem time‐of‐flight mass spectrometer equipped with a second source for delayed extraction/post‐acceleration of product ions
Authors: Moon Jeong Hee , Shin Young Sik , Cha Hyun Jung , Kim Myung Soo
Published: January 2007

A tandem time‐of‐flight mass spectrometer was built for photodissociation (PD) of singly protonated peptides and small proteins generated by matrix‐assisted laser desorption/ionization. PD was performed in a second source after deceleration of precursor ions. The delayed extraction/post‐acceleration scheme was used for the product ions. For the PD at 193 nm of small singly protonated peptides, the present instrument showed much better sensitivity and resolution for product ions than the previous one (Moon JH, Yoon SH, Kim MS, Bull. Korean Chem. Soc. 2005; 26: 763) even though the overall spectral patterns obtained with the two instruments were similar. The present instrument was inferior in precursor ion selection and background noise level. PD was achieved for precursor ions as large as the singly protonated ubiquitin (m/z 8560.63), indicating that the photoexcitation is capable of supplying a sufficient amount of internal energy to dissociate large singly protonated proteins. As the precursor ion m/z increased, however, product ion signals deteriorated rather rapidly. As in the PD of small peptide ions with m/z around 1000, the types of the product ions generated from singly protonated peptides with m/z in the range 2000–4000 were mostly determined by the positions of arginine residues. Namely, an and dn ions dominated when an arginine residue(s) was near the N‐terminus while vn, wn, xn and yn dominated when the same residue(s) was near the C‐terminus. In addition, dn, vn and wn ions were generated according to the correlation rules previously observed in the collisionally activated dissociation. Isoleucine and leucine isomers could be easily distinguished based on the wn and dn ions. Copyright © 2007 John Wiley & Sons, Ltd.
Use of a variably sensitive selected reaction monitoring method to extend the linear dynamic range for quantitative high‐performance liquid chromatography/tandem mass spectrometry
Authors: Fries Harvey E. , Aiello Mauro , Evans Christopher A.
Published: January 2007

A method has been devised with the capacity to extend the linear dynamic range of a triple quadrupole mass spectrometer operated in the selected reaction monitoring (SRM) mode of analysis. This extended range experiment can be realized by simultaneously acquiring variably sensitive data, via collision energy adjustment, for the same precursor‐to‐product ion transition within a single SRM method. While this method can be applied universally to many different study types without any detrimental effect to the analysis or throughput, it was applied herein to acquire and quantify, within a single analysis, the concentrations of GSK‐A in a multiple‐dose rodent study, that previously required a dilution scheme. Using this methodology, the linear dynamic range of GSK‐A was increased over traditional methods by nearly two orders of magnitude, from 2.00–10 000 ng/mL to 0.500–100 000 ng/mL. Copyright © 2007 John Wiley & Sons, Ltd.
A generalized gamma software reliability model
Authors: Okamura Hiroyuki , Ando Mitsuaki , Dohi Tadashi
Published: January 2007

In this paper, the authors propose a generalized software reliability model based on a nonhomogeneous Poisson process (NHPP), on the assumption that software fault discovery times follow a generalized gamma distribution. The proposed model encompasses representative NHPP models developed before now and is also consistent with probabilistic debugging theory based on the concept of generalized order statistics. Furthermore, in this paper, the authors propose a parameter estimation method which combines the EM (Expectation‐Maximization) algorithm and a heuristic solution method, as an effective parameter estimation method for the generalized gamma software reliability model. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(2): 81–90, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20350
Face recognition under variable pose and illumination conditions using 3D facial appearance models
Authors: Ishiyama Rui , Hamanaka Masahiko , Sakamoto Shizuo
Published: January 2007

This paper proposes a method in which an appearance model is constructed from 3D facial shape data that can describe the image variation due to the arbitrariness of the pose and the variation of the illumination, after which recognition is performed by fitting the model to facial images when the illumination conditions and the precise pose are unknown. The appearance model in the proposed method is constructed as follows. The illumination basis for an image of an arbitrary pose is derived from the geodesic illumination basis describing the brightness on the 3D object surface depending on the illumination variations, and an image with the same illumination condition is reproduced as the target image for the unknown illumination conditions. By optimizing the pose to minimize the reproduction error, model fitting with high accuracy is realized even if the exact pose is unknown. By experiment, the number of illumination samples needed in the calculation of the geodesic illumination basis is evaluated and it is verified that the proposed appearance model can describe arbitrary illumination variations in images with various poses. The robustness of the proposed pose optimization method against initial pose estimate is also evaluated. The effectiveness of the proposed method is demonstrated by a recognition experiment using 14,000 facial images taken in various situations, including extreme illumination variations such as backlighting, for a wide range of poses from frontal to 45° upward and 60° sidewise. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(2): 57– 70, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/scj.20646
Bridge layer for content distribution
Authors: Shin Kilho , Takeda Koji , Taguchi Masahiro , Yasuda Hiroshi , Aoki Terumasa
Published: January 2007

In this paper, the authors propose a bridge layer as a framework for the safe and free association of existing content architectures (CA) and payment and rights‐management services (CHS: Clearinghouse Services). The unauthorized use of content through the circumvention of payment and rights‐management is a serious threat. To eliminate this threat, the CHS must associate with the inherent content protection function provided by the CA closely. However, ad hoc association has problems relating to development and maintenance costs, motivation for association, and security, which become impediments to content distribution. A bridge layer provides a protocol for the association of a CA with the CHS, as well as the security functions called for by association. Because the CA and CHS comply with the bridge layer protocol, association is automatically implemented and the unauthorized use of content through circumvention is prevented. In this paper, the required technical elements of the bridge layer are clarified and an actual system satisfying these requirements is proposed. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(2): 46– 56, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20659
Spinal alignment measurement in standing position using stereo‐view roentgenography without positional calibration
Authors: Tashiro Takahito , Nakajima Yoshikazu , Tamura Yuichi , Yonenobu Kazuo , Uji Shigeru , Yoshikawa Hideki , Ochi Takahiro , Tamura Shinichi
Published: January 2007

In the treatment of the spine, knowledge of spinal alignment in a standing position, specifically the relative three‐dimensional positional relationship between the vertebrae comprising the spine, is very important. In spinal medicine at present, this is generally measured using two‐dimensional X‐ray images, but it is difficult to measure three‐dimensional changes such as the axial rotation of the vertebra. For this reason, measurement techniques have been proposed which use 2D/3D registration methods, three‐dimensional statistical models, and the correspondence of interest points in the images. However, these techniques require the use of special equipment and the acquisition of the position of the X‐ray imaging device; this is not practical for clinical applications. In this paper, the authors propose a spinal alignment measurement technique which employs only medical equipment which is in general use. In the proposed method, spinal alignment is measured by simultaneously estimating the positions of the vertebrae comprising the spine and the position of the X‐ray imaging device. The proposed technique makes possible three‐dimensional spinal alignment measurement without changes to current spinal medicine protocols. In this paper, the authors conducted a computer simulation experiment and an experiment using real images, compared the performance of the proposed method with that of conventional methods, and verified the properties of the proposed method. As a result, it was confirmed that the proposed method is effective for measuring the relative positions of vertebrae, as in spinal alignment. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(2): 32– 45, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20663
Query processing methods considering the deadline of queries for database broadcasting systems
Authors: Kitajima Shinya , Terada Tsutomu , Hara Takahiro , Nishio Shojiro
Published: January 2007

In recent years, there has been an increasing interest in the database broadcasting system where the server periodically broadcasts contents of a database to mobile clients such as portable computers and PDAs. There are three query processing methods in the database broadcasting system: (i) the server processes a query and then broadcasts the query result to the client, (ii) the client stores all data that are necessary to process the query and then processes it locally, and (iii) the server and the client collaborate in processing the query. Since the performance of each method changes according to the situation such as the interval of query generation and the size of query results, it is difficult to choose the optimal method among them statically. In this paper, we propose new query processing methods which dynamically change the order of queries submitted in the queue at the server and also change processing methods for the queries according to the deadline of queries and the system situation. These methods improve the success rate as well as reduce the response time in most cases. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(2): 21– 31, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20689
One‐ and two‐stage designs for phase II window studies
Authors: Chang Myron N. , Devidas Meenakshi , Anderson James
Published: January 2007

The primary goal of phase II window studies in cancer is testing new single agents or combination therapies for newly diagnosed patients who are less likely to have multiple‐drug‐resistant tumours than the typical phase II patients who have failed one or more chemotherapeutic regimens. In addition, by utilizing newly diagnosed patients, one can assess the responsiveness in a population more representative of where the phase II agent might be applied in a true phase III setting. In general, the outcome of a patient on a phase II window study can be categorized as response, stable disease, or early disease progression. Phase II window studies sometimes require early stopping rules for both insufficient response rate and excessive early progression rates. In this paper, one‐stage and two‐stage designs for phase II window studies are developed, requiring the monitoring of two rates. It is shown that the power function is monotone in response rate and early disease progression rate. Consequently, the significance level and power are easy to compute. Computational procedures are described and examples are provided. The proposed method can be applied to other studies with categorical outcomes. Copyright © 2007 John Wiley & Sons, Ltd.
Prior data for non‐normal priors
Authors: Greenland Sander
Published: January 2007

Data augmentation priors facilitate contextual evaluation of prior distributions and the generation of Bayesian outputs from frequentist software. Previous papers have presented approximate Bayesian methods using 2×2 tables of ‘prior data’ to represent lognormal relative‐risk priors in stratified and regression analyses. The present paper describes extensions that use the tables to represent generalized‐F prior distributions for relative risks, which subsume lognormal priors as a limiting case. The method provides a means to increase tail‐weight or skew the prior distribution for the log relative risk away from normality, while retaining the simple 2×2 table form of the prior data. When prior normality is preferred, it also provides a more accurate lognormal relative‐risk prior in for the 2×2 table format. For more compact representation in regression analyses, the prior data can be compressed into a single data record. The method is illustrated with historical data from a study of electronic foetal monitoring and neonatal death. Copyright © 2007 John Wiley & Sons, Ltd.
Modelling effectiveness of internally heterogeneous organizations in the presence of survey non‐response: an application to the ULTRA study
Authors: Ohman Strickland Pamela A. , Crabtree Benjamin F.
Published: January 2007

Levels of turbulence and uncertainty in family medicine practices participating in the ULTRA study are measuredviaa survey from heterogeneous viewpoints within each practice, including clinicians, nursing staff and office staff. In order to examine the effect of the average practice ‘chaos’ score on screening provided to patients, the analysis needed to account for large amounts of missing survey responses. Patterns of missing data included portions of missing responses within a job group (e.g. one out of three clinicians) to missing responses from whole subgroups within a practice (e.g. all three clinicians) to a whole practice of missing survey responses (e.g. all clinicians, nursing staff and office staff). The expectation–maximization (EM) algorithm, using a hierarchical model for covariate information, is used to handle the missing data. It was found that the varied patterns of missingness of survey responses among the heterogeneous subgroups within the practices had large effects on estimated effects of practice chaos on patient care. Copyright © 2007 John Wiley & Sons, Ltd.
Probability estimation when some observations are grouped
Authors: Tarima Sergey S. , Slavova Svetla S. , Fritsch Travis A. , Hall Laura M.
Published: January 2007

This paper considers the use of additional questions for decreasing survey non‐response rates and an approach for estimating a probability based on the results obtained. In a survey, the respondents are asked to answer an original question and follow‐up questions, where the answers for the follow‐up questions are grouped answers for the original question. For example, respondents are asked to provide an exact number of incidents, but in cases of ‘Do not know’ or ‘Refuse’ responses, they are subsequently asked to pick an answer from a less specific categorical scale. The new estimator obtains smaller variance asymptotically and does not depend on a distribution family. This method is applied to income questions in a survey regarding injury prevention and behaviours. Another application is survey data on intimate partner violence, where some amendments were applied for incorporating post‐stratification weights and for using non‐random grouping. For additional illustration, an example of parameter estimation on artificially generated data is presented. Copyright © 2007 John Wiley & Sons, Ltd.
Prenatal diagnosis of malformations of cortical development by dedicated neurosonography
Authors: Malinger G. , Kidron D. , Schreiber L. , Ben‐Sira L. , Hoffmann C. , Lev D. , Lerman‐Sagie T.
Published: January 2007

Objective

Malformations of cortical development (MCD) are rarely diagnosed in utero. We describe and compare the ultrasonographic and pathology findings in a cohort of fetuses with MCD.

Methods

Fetuses with MCD were identified among all fetuses evaluated for suspected brain anomalies at the Fetal Neurology Clinic, and the ultrasonographic findings were compared with the results of the pathology examination.

Results

We suspected the presence of MCD by ultrasonography in 23 fetuses. The mean gestational age at the time of ultrasound diagnosis was 26.2 (range, 18–40) weeks. The ultrasonographic findings leading to the diagnosis of MCD were abnormally overdeveloped gyri and sulci for gestational age (n = 7), delay in sulcation (n = 5), abnormally thin cortex (n = 5) abnormally wide and broad sulci (n = 3), bulging into the lateral ventricle (n = 1), cortical cleft (n = 1), and multiple intraparenchymal echogenic nodules (n = 1). All fetuses had associated central nervous system (CNS) and/or non‐CNS anomalies. Pathology examination (performed in 17 fetuses) confirmed MCD in 16.

Conclusions

Cortical malformations can be diagnosed in utero by ultrasonography based on the presence of specific deviations from the normal pattern of development. The identified cases may represent the more severe forms in the MCD spectrum. The pathology findings do not always conform to the current classification systems of MCD but help in differentiating between possible genetic and acquired etiologies and in some cases provide a definitive syndromic diagnosis. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Laparoscopic Appendectomy: Differences between Male and Female Patients with Suspected Acute Appendicitis
Authors: Tzovaras George , Liakou Paraskevi , Baloyiannis Ioannis , Spyridakis Michael , Mantzos Fotios , Tepetes Konstantinos , Athanassiou Evaghelos , Hatzitheofilou Constantine
Published: January 2007

Background

The role of laparoscopy in the management of patients with suspected acute appendicitis remains controversial. It has been suggested that laparoscopy is useful mainly in young women of reproductive age because of the high incidence of wrong diagnosis in these patients.

Methods

Different management protocols for patients with suspected acute appendicitis were prospectively used in male and female patients; women of reproductive age were treated laparoscopically, while men were randomised to open or laparoscopic appendectomy.

Results

From September 2002 to September 2005, 132 patients—54 women and 78 men—with suspected acute appendicitis were treated according to the protocol. The incidence of wrong diagnosis in female patients was high (26% and the conversion rate low (5.5%). In contrast, in the laparoscopic male subgroup, these rates showed a reverse relationship (5.2% and 18.5%, respectively). Morbidity did not differ between female and male patients or between the 2 arms of the male group. Laparoscopic appendectomy took longer to perform without affecting significantly the needs for postoperative analgesia, the duration of hospital stay and the time to return to normal activities when compared with open appendectomy in men.

Conclusion

Laparoscopic appendectomy is at least as safe as the open procedure in the male population, although it does not appear to offer any obvious advantage over the open procedure. The diagnostic advantage that laparoscopy offers to fertile women makes the procedure attractive for this population.
Response of nutrient dynamics of decomposing pine (Pinus massoniana) needles to simulated N deposition in a disturbed and a rehabilitated forest in tropical China
Authors: Mo Jiangming , Brown Sandra , Xue Jinghua , Fang Yunting , Li Zhian , Li Dejun , Dong Shaofeng
Published: January 2007

The effects of simulated N deposition on changes in mass, C, N and P of decomposing pine (Pinus massoniana) needles in a disturbed and a rehabilitated forest in tropical China were studied during a 24‐month period. The objective of the study was to test the hypothesis that litter decomposition in a disturbed forest is more sensitive to N deposition rate than litter decomposition in a rehabilitated forest due to the relatively low nutrient status in the former as a result of constant human disturbance (harvesting understory and litter). The litterbag method and N treatments (control, no N addition; low‐N, 5 g N m−2year−1; medium‐N, 10 g N m−2year−1) were employed to evaluate decomposition. The results revealed that N addition increased (positive effect) mass loss rate and C release rate but suppressed (negative effect) the release rate of N and P from decomposing needles in both disturbed and rehabilitated forests. The enhanced needle decomposition rate by N addition was significantly related to the reduction in the C/N ratio in decomposing needles. However, N availability is not the sole factor limiting needle decomposition in both disturbed and rehabilitated forests. The positive effect was more sensitive to the N addition rate in the rehabilitated forest than in the disturbed forest, however the reverse was true for the negative effect. These results suggest that nutrient status could be one of the important factors in controlling the response of litter decomposition and its nutrient release to elevated N deposition in reforested ecosystems in the study region.
Identification and quantification of glycerolipids in cotton fibers: Reconciliation with metabolic pathway predictions from DNA databases
Authors: Wanjie Sylvia W. , Welti Ruth , Moreau Robert A. , Chapman Kent D.
Published: January 2007

The lipid profiles of cotton fiber cells were determined from total lipid extracts of elongating and maturing cotton fiber cells to see whether the membrane lipid composition changed during the phases of rapid cell elongation or secondary cell wall thickening. Total FA content was highest or increased during elongation and was lower or decreased thereafter, likely reflecting the assembly of the expanding cell membranes during elongation and the shift to membrane maintenance (and increase in secondary cell wall content) in maturing fibers. Analysis of lipid extracts by electrospray ionization and tandem MS (ESI‐MS/MS) revealed that in elongating fiber cells (7–10 d post‐anthesis), the polar lipids—PC, PE, PI, PA, phosphatidylglycerol, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, and phosphatidyl‐glycerol—were most abundant. These same glycerolipids were found in similar proportions in maturing fiber cells (21 dpa). Detailed molecular species profiles were determined by ESI‐MS/MS for all glycerolipid classes, and ESI‐MS/MS results were consistent with lipid profiles determined by HPLC and ELSD. The predominant molecular species of PC, PE, PI, and PA was 34∶3 (16∶0, 18∶3), but 36∶6 (18∶3, 18∶3) also was prevalent. Total FA analysis of cotton lipids confirmed that indeed linolenic (18∶3) and palmitic (16∶0) acids were the most abundant FA in these cell types. Bioinformatics data were mined from cotton fiber expressed sequence tag databases in an attempt to reconcile expression of lipid metabolic enzymes with lipid metabolite data. Together, these data form a foundation for future studies of the functional contribution of lipid metabolism to the development of this unusual and economically important cell type.
Dietary α‐linolenic acid increases brain but not heart and liver docosahexaenoic acid levels
Authors: Barceló‐Coblijn Gwendolyn , Collison Lauren W. , Jolly Christopher A. , Murphy Eric J.
Published: January 2007

Fish oil‐enriched diets increase n−3 FA in tissue phospholipids; however, a similar effect by plant‐derived n−3 FA is poorly defined. To address this question, we determined mass changes in phospholipid FA, individual phospholipid classes, and cholesterol in the liver, heart, and brain of rats fed diets enriched in flax oil (rich in 18∶3n−3), fish oil (rich in 22∶6n−3 and 20∶5n−3), or safflower oil (rich in 18∶2n−6) for 8 wk. In the heart and liver phospholipids, 22∶6n−3 levels increased only in the fish oil group, although rats fed flax oil accumulated 20∶5n−3 and 22∶5n−3. However, in the brain, the flax and fish oil diets increased the phospholipid 22∶6n−3 mass. In all tissues, these diets decreased the 20∶4n−6 mass, although the effect was more marked in the fish oil than in the flax oil group. Although these data do not provide direct evidence for 18∶3n−3 elongation and desaturation by the brain, they demonstrate that 18∶3n−3‐enriched diets reduced tissue 20∶4n−6 levels and increased cellular n−3 levels in a tissuedependent manner. We hypothesize, based on the lack of increased 22∶6n−3 but increased 18∶3n−3 in the liver and heart, that the flax oil diet increased circulating 18∶3n−3, thereby presenting tissue with this EFA for further elongation and desaturation.
Effects of aging and dietary n−3 fatty acids on rat brain phospholipids: Focus on plasmalogens
Authors: André A. , Juanéda P. , Sébédio J. L. , Chardigny J. M.
Published: January 2007

The aging brain undergoes modifications in the lipid composition of cell membranes and especially in plasmalogens. These phospholipids represent between one‐half and twothirds of the ethanolamine phospholipids in the brain. They are known to facilitate membrane fusion and act as endogenous antioxidants. During normal aging and in some pathological conditions, plasmalogen and DHA levels fall. In this context, we aimed to evaluate the influence of n−3 FA intake on plasmalogens in the brain during aging. Littermates from two generations of n−3‐deficient rats were fed an n−3‐deficient diet or an equilibrated diet containing either α‐linolenic acid alone (α‐LNA) or with two doses of DHA (0.3 or 0.6% w/w). After weaning, 9 mon of diet, or 21 mon of diet, plasmalogen levels were assessed, and the sn‐2 substitutions of plasmenylethanolamines were analyzed in the cortex, striatum, and hippocampus. Our results showed that plasmalogen contents were not influenced by the diet. Plasmalogen levels were significantly decreased in aged rats compared with adults, whereas DHA levels increased in the hippocampus and remained stable in the cortex and striatum. DHA levels were significantly and similarly increased in total phospholipids and especially in plasmenylethanolamines after 9 mon of diet containing α‐LNA alone or combined with DHA. This study showed that each structure sustained specific age‐induced modifications. Dietary n−3 FA may not oppose the physiological decrease in brain plasmalogen levels during aging. Moreover, α‐LNA appears to be equally as potent as preformed DHA at replacing DHA in the brain of our rat model.