bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of digital polarity correlators in a sonar ranging system
Authors: Kodama Tetsuji , Nakahira Kenji , Kanaya Yuuki , Yoshikawa Takahiko
Published: October 2008

In robotics applications, ultrasonic transducers are frequently used as rangefinders, due to their low cost and small size. The pulse compression techniques were adopted to locate multiple objects at the same time and to eliminate frequent misreadings caused by crosstalk or external ultrasound sources. However, a few problems become apparent when implementing the pulse compression techniques. First, each transducer must be equipped with a processing system for the implementation of correlation functions. This may significantly increase the complexity of the total system, cutting down one of the advantages of ultrasonic systems. Second, the majority of transducers for use in air are based on piezoelectric design, which is usually used over a narrow bandwidth. Among digital correlators, significant reductions of the processing cost can be achieved with a polarity correlator. However, this polarity correlation adds quantization noise to the signals and leads to a degradation of the output signal‐to‐noise ratio. This paper presents an analysis of the polarity correlator applied to a sonar ranging system, consisting of piezoelectric transducers and a chirp filter. A numerical evaluation of the output signal shows that the signal‐to‐noise ratio degrades only a small amount comparable with that obtained by direct digital correlators. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(4): 20– 26, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10077
PAPR reduction of OFDM signal by neural networks without side information and its FPGA implementation
Authors: Ohta Masaya , Ueda Yasuo , Yamashita Katsumi
Published: October 2008

A major drawback of orthogonal frequency division multiplexing (OFDM) is the high peak‐to‐average power ratio (PAPR) of the transmitted signal. PAPR reduction techniques by using neural networks have been proposed to reduce the PAPR problem in OFDM transmitter. These techniques require side information to be transmitted from the transmitter to the receiver in order to recover the original data symbol from the receive signal. In this paper, we propose a novel technique to reduce PAPR of OFDM signal. The proposed technique is based on tone injection (TI) and does not use any side information to be transmitted from the transmitter to the receiver. Moreover, the proposed model is designed with VHDL for an FPGA device, and we report evaluation of the performance. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(4): 52–60, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10081
Tr1 and naturally occurring regulatory T cells induce IgG4 in B cells through GITR/GITR‐L interaction, IL‐10 and TGF‐β
Authors: Satoguina Judith S. , Adjobimey Tomabu , Arndts Kathrin , Hoch Jochen , Oldenburg Johannes , Layland Laura E. , Hoerauf Achim
Published: October 2008

Regulatory T cells exert their function through the modulation of both T and B cell responses. Our previous studies demonstrated that IL‐10‐producing Treg (Tr1) can induce B cells to secrete IgG4 in a cell‐contact‐dependent manner. The benefit of such non‐inflammatory B‐cell responses is apparent in the hyporesponsive state of patients with helminth infections such as Onchocerciasis. Here, we investigated the mechanisms involved to induce IgG4, within B:Tr‐cell co‐cultures, using IL‐10‐producing tetanus‐toxoid‐specific regulatory T cell lines and clones (Tr‐TCC) from human PBMC. During the generation process, we found that increasing Foxp3 levels in regulatory T cell lines correlated with their ability to induce IgG4 in B cells. Using Tr‐TCC, we found that blocking glucocorticoid‐induced tumour necrosis factor receptor‐related protein (GITR) molecules selectively prevented IgG4 production as did neutralizing Ab to glucocorticoid‐induced tumour necrosis factor receptor‐related protein ligand (GITR‐L), IL‐10 and TGF‐β. Furthermore, the prevention of IgG4 induction by anti‐GITR Ab was reversed by excess rIL‐10 but not rTGF‐β. In contrast, anti‐ICOS and anti‐CTLA‐4 Abs had no effect. When compared with Tr‐TCC, freshly isolated CD4+CD25+ T cells, but not effector T cell populations, induced low levels of IgG4, which were also blocked by anti‐GITR and anti‐GITR‐L Ab. Thus, the mechanism of IgG4 induction by regulatory cells involves GITR–GITR‐L interactions, IL‐10 and TGF‐β.
Increased diabetes development and decreased function of CD4+CD25+ Treg in the absence of a functional DAP12 adaptor protein
Authors: Hall Håkan T. L. , Sjölin Hanna , Brauner Hanna , Tomasello Elena , Dalod Marc , Vivier Eric , Höglund Petter
Published: October 2008

Prior to the development of type 1 diabetes, T cells are primed in the pancreatic lymph nodes (PLN) where they interact with APC displaying β cell‐derived peptides. The details concerning the regulation of autoreactive T cell responses in the PLN are unclear. BDC2.5/B6g7 TCR transgenic mice represent a simplified model of type 1 diabetes, in which β cell‐specific CD4+ T cells expressing a diabetogenic transgenic TCR are first activated in the PLN and subsequently home to the pancreas where they mediate killing of β cells. DNAX‐activating protein of 12 kDa (DAP12) is an adaptor molecule carrying an ITAM motif. It associates with receptors on lymphoid and myeloid cells, including APC. We here show that introduction of a DAP12 null mutation in BDC2.5/B6g7 mice accelerated diabetes development and promoted an augmented activation state of PLN T cells expressing the transgenic TCR. Transferred BDC2.5 T cells proliferated more efficiently in the PLN of DAP12‐deficient B6g7 recipients, which correlated with a decreased impact of co‐transferred BDC2.5+CD4+CD25+ T cells. We propose that signaling through a DAP12‐associated receptor on APC facilitates activation of Treg in the PLN and by this contributes to the maintenance of peripheral tolerance to β cell‐derived antigens.
Evasion of macrophage scavenger receptor A‐mediated recognition by pathogenic streptococci
Authors: Areschoug Thomas , Waldemarsson Johan , Gordon Siamon
Published: October 2008

PRR recognize conserved structures on pathogenic microbes and are important for the defense against invading microorganisms. However, accumulating evidence indicates that many pathogens have evolved mechanisms to avoid recognition by PRR. One type of PRR is the macrophage scavenger receptor A (SR‐A), which has been shown to play an important role in recognition and non‐opsonic phagocytosis of pathogenic bacteria. The bacterial ligands for SR‐A have been suggested to be LPS or lipoteichoic acid. Here, we use murine bone marrow‐derived macrophages to analyze the role of SR‐A in non‐opsonic phagocytosis of two major Gram‐positive pathogens, Streptococcus agalactiae (group B streptococcus; GBS) and Streptococcus pyogenes. We show that the polysaccharide capsule of GBS and the surface M protein of S. pyogenes, two important virulence factors, prevent SR‐A‐mediated non‐opsonic phagocytosis of streptococci. The sialic acid moiety of the GBS capsule was crucial for its ability to prevent recognition by SR‐A. Moreover, we show that a ligand on GBS recognized by SR‐A in the absence of capsule is the surface lipoprotein Blr. These findings represent the first example of a microbial strategy to prevent recognition by SR‐A and suggest that bacterial surface proteins may be of importance as ligands for SR‐A.
Allergy therapy: The therapeutic potential of targeting sphingosine kinase signalling in mast cells
Authors: Melendez Alirio J.
Published: October 2008

Mast cell activation is a central event in allergic diseases, and investigating the signalling pathways triggered during mast cell activation may lead to the discovery of novel therapeutic targets. Mast cells can be activated by a multitude of stimuli including antibodies/antigen, cytokines/chemokines and neuropeptides, resulting in a variety of responses including the immediate release of potent inflammatory mediators. Moreover, recent data suggest that mast cell‐mediated responses are also influenced by the differential sphingolipids/sphingosine to sphingosine‐1‐phosphate ratio. The importance of sphingolipids as potent biological mediators of both intracellular and extracellular responses is being increasingly recognized and accepted; it is now appreciated that activation of mast cells, via the high‐affinity IgE‐receptor (FcεRI) leads to the activation of sphingosine kinases (SphK), resulting in increased formation of sphingosine‐1‐phosphate. Furthermore, FcεRI activates SphK‐dependent calcium mobilization in mast cells, leading to degranulation, cytokine, and eicosanoid production, and chemotaxis. In the past two years a critical role for SphK in allergic responses in vivo has emerged. In this review, I focus on the current understanding of the role of sphingosine kinases during mast cell signalling in vitro and their role during hypersensitivity responses in vivo, and discuss the potential of these enzymes as novel therapeutic targets to treat allergic diseases.
Synthesis of Chiral Amines Using α‐Amino Aldehydes (Eur. J. Org. Chem. 31/2008)
Authors: Hili Ryan , Baktharaman Sivaraj , Yudin Andrei K.
Published: October 2008

The cover picture is an attempt to represent a cornucopia of molecules that are derived from α‐amino aldehydes. One hundred years ago, Emil Fischer attempted to prepare glycinal, a prototypical α‐amino aldehyde. Although glycinal resisted isolation and was found to be too unstable, it did provide a foundation for numerous synthetic studies of related molecules. Over the last century this field has flourished, proving the lasting value of these important synthetic intermediates. A. K.Yudin et al. summarize the latest trends in α‐amino aldehyde synthesis and applications on p. 5201 ff. The cover art was created by Mr. Ryan Hili. The authors gratefully acknowledge ongoing financial support from NSERC.
Bibliography review on applications of correlation analysis in power system operation and planning
Authors: Lim Jung‐Uk , Jiang John N.
Published: October 2008

Fast growth of large‐scale distributed renewable energy resources, electric power markets, and responsive demand impose significant amount of correlated uncertainties on operation of the power system from both resource side and load side. Understanding the correlations between these uncertainties and applying sophisticated correlation analysis of multiple dependent uncertainties is a defining issue for the development of methodologies and technologies for power system operation in the new era.

Application of correlation analysis in operation of the power system is not as fully explored as many other methodologies. The complexity of mathematic modeling of multiple correlated random variables challenges the power system professionals. The research is further challenged by lacking of operational experience and empirical investigation challenges.

This paper provides a bibliography survey on application of correlation analysis in operation of the power system. The scope of the review covers IEEE power systems proceedings, IEEE and IEE transactions published after 1980. There are 77 relevant papers identified. These papers are put into seven technical categories: power system reliability, wind generation, power market analysis, load forecast, resource planning and dispatch, transmission load flow, other non‐operation‐related topics. Copyright © 2008 John Wiley & Sons, Ltd.
Switching between the SA‐DCT and the EI‐DCT in arbitrarily shaped image coding
Authors: Freitas Flávia Magalhães , Alcaim Abraham
Published: October 2008

In object‐oriented image coding applications, the use of the SA‐DCT (Shape‐Adaptive Discrete Cosine Transform) and of the block‐based DCT schemes associated to the EI (Extension‐Interpolation) padding technique have shown promising results at high and low bit rates, respectively. Both the SA‐DCT and the EI padding algorithm consist of two 1D‐DCT processing. Recent works have shown that their efficiencies can be further improved by the most appropriate selection of the first direction to be processed. This paper introduces novel methods to determine the preferential direction of processing boundary blocks of the SA‐DCT and of the EI padding technique. These methods are based on two known strategies related to the variances of the lengths of object segments in both directions, and a third one, which measures the energy compaction efficiency of the transforms. The proposed methods use the morphological feature TNOP (distribution of Texture according to the Number of Object Pixels) to adaptively select the most adequate strategy for each group of boundary blocks exhibiting similar number of object pixels. At last, it is introduced an adaptive switching scheme that selects between the proposed scheme for the block‐based DCT or for the SA‐DCT, when the available bit rate is known. This novel scheme allows different switching rules for distinct groups of boundary blocks, according to the feature TNOP. It outperforms the isolated use of both the SA‐DCT and the block‐based DCT schemes, at any specific bit rate. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 219–227, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).
Inverse scattering of buried inhomogeneous biaxial dielectric cylinders coated on a conductor
Authors: Huang Chung‐Hsin , Liu Chun‐Liang , Lin Chun Jen , Chiu Chien‐Ching
Published: October 2008

The inverse scattering of buried inhomogeneous biaxial dielectric cylinders coated on a conductor with known cross section is investigated. Dielectric cylinders with known cross section coated on a conductor of unknown permittivities are buried in one half space and scatter a group of unrelated waves incident from another half space where the scattered field is recorded. By proper arrangement of the various unrelated incident fields, the difficulties of ill‐posedness and nonlinearity are circumvented, and the permittivity distribution can be reconstructed through simple matrix operations. The algorithm is based on the moment method and the unrelated illumination method. Numerical results are given to demonstrate the capability of the inverse algorithm. Good reconstruction is obtained both with and without Gaussian noise in measured data. In addition, the effect of noise on the reconstruction result is also investigated. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 228–236, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).
Video compression by bit‐plane watermarking
Authors: Wang Chuen‐Ching , Chen Bo‐Yu
Published: October 2008

This article proposes a new fragile watermarking scheme named bit‐plane watermarking (BPW) which considers ways to improve coding efficiency whereas providing watermarking capability. Because of the use of the run‐length coding strategy for embedding watermark information, the BPW not only verifies the authenticity and integrity of video streams, but also can recompress the bit streams for improving the compression ratio. To verify the effectiveness of this new concept, we select the MPEG‐4 FGS as the platform for implementation. The watermark is embedded in the bit‐plane blocks of MPEG‐4 FGS enhancement layer bitstream, and the coefficient in each bit‐plane block is automatically selected so that the run‐length symbols can be reduced and the location of embedded bits is not required to memorize. The effectiveness of the proposed scheme is demonstrated in a series of experimental simulations. It is shown that the scheme successfully detects changes made to the content of MPEG‐4 FGS video streams and identifies the specific location at which these changes have been made. Furthermore, the results show that the scheme can further reduce the length of compressed bit stream. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 257–264, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).
An efficient gait recognition based on a selective neural network ensemble
Authors: Lee Heesung , Hong Sungjun , Kim Euntai
Published: October 2008

The neural network ensemble is a learning paradigm where a collection of neural networks is trained for the same task. Generally, the ensemble shows better generalization performance than a single neural network. In this article, a selective neural network ensemble is applied to gait recognition. The proposed method selects some neural network based on the minimization of generalization error. Since the selection rule is directly incorporated into the cost function, we can obtain adequate component networks to constitute an ensemble. Experiments are performed with the NLPR database to show the performance of the proposed algorithm. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 237–241, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).
Effects of estradiol on the development of the bursa of Fabricius in Japanese quail
Authors: Quinn Michael James , McKernan Moira , Lavoie Emma T. , Ottinger Mary Ann
Published: October 2008

Effects of androgens on the development of the bursa of Fabricius are better understood than those of estradiol, despite the known sensitivity of the bursa to estradiol early in embryogenesis. The goal of this study was to determine the effects of one‐time yolk injections of estradiol at day 4 of incubation on the development of the bursa and spleen as indices of treatment effects on the immune system. Follicle size and numbers in hatchling bursas were significantly reduced at 50 and 500 μg/egg, respectively. Additionally, distorted plicae and thicker epithelial layers surrounding the plicae were observed in day‐old chicks at the same treatment levels. Adult bursas from birds embryonically exposed to estrogen were significantly larger than controls, suggesting an inhibition of natural bursal regression. Although estradiol altered the development of the bursa, the spleen appeared to be unaffected. The observed effects of estradiol on the development of the bursa indicate that this lymphoid organ may be a target for developmental disruption by estrogenic endocrine disrupting chemicals, though long‐term consequences of embryonic exposure on immune function remain unknown. J. Exp. Zool. 311A:91–95, 2009. © 2008 Wiley‐Liss, Inc.
The Role of Self‐Dilution in Step‐Growth Polymerizations
Authors: Kricheldorf Hans R.
Published: October 2008

In step‐growth polymerizations, the molar concentration of reactive linear species (oligomers and polymers) decreases with higher conversions and finally reaches zero at 100% conversion. This self‐dilution favors cyclization at the expense of chain‐growth. Cyclization reduces the average lengths of the linear species, and thus, induces a kind of “self‐acceleration”. Both effects together overcompensate the decreasing cyclization tendency resulting from increasing chain lengths. This influence of the self‐dilution is also operating in the case of “abn” monomers, so that at 100% conversion (defined for the “a” functional groups) all hyperbranched polymers will have a cyclic core. With modifications, the “law of self‐dilution” also applies to “a2 + b3” or “a2 + b4” polycondensations. Furthermore, the “law of self‐dilution” is valid for both kinetically‐ and thermodynamically‐controlled polycondensations.

magnified image
Synthesis of Poly(glycidyl methacrylate)‐block‐Poly(pentafluorostyrene) by RAFT: Precursor to Novel Amphiphilic Poly(glyceryl methacrylate)‐block‐Poly(pentafluorostyrene)
Authors: Gudipati Chakravarthy S. , Tan Maureen B. H. , Hussain Hazrat , Liu Ye , He Chaobin , Davis Thomas P.
Published: October 2008

Poly(glycidyl methacrylate) (PGMA) was synthesized by the RAFT method in the presence of 2‐cyanoprop‐2‐yl dithiobenzoate (CPDB) chain transfer agent using different [GMA]/[CPDB] molar ratios. The living radical polymerization resulted in controlled molecular weights and narrow polydispersity indices (PDI) of ≈1.1. The polymerization of pentafluorostyrene (PFS) with PGMA as the macro‐RAFT agent yielded narrow PDIs of ≤1.2 at 60 °C and ≤1.5 at 80 °C. The epoxy groups of the PGMA block were hydrolyzed to obtain novel amphiphilic copolymer, poly(glyceryl methacrylate)‐block‐poly(pentafluorostyrene) [PGMA(OH)‐b‐PPFS]. The PGMA epoxy group hydrolysis was confirmed by 1H NMR and FTIR spectroscopy. DSC investigation revealed that the PGMA‐b‐PPFS polymer was amorphous while the PGMA(OH)‐b‐PPFS displayed a high degree of crystallinity.

magnified image
Ability and specialization among economic researchers
Authors: Kendall Todd D.
Published: October 2008

It is not obvious whether a firm's more talented workers should be more specialized, and in fact, the relationship between ability and specialization seems to differ across industries. In this paper, I examine the case of knowledge production in economic research, and find that abler economists tend to publish more general research. This result suggests substitutability between general and specialized skill in research. Copyright © 2008 John Wiley & Sons, Ltd.
A model to evaluate transient industry effects
Authors: Ariño Miguel A. , Ariño Africa , Garcia‐Castro Roberto
Published: October 2008

In this paper we present a model to evaluate transient industry effects, that is, the impact of business cycles on the industry. While the importance of the economic cycle for industry and firm performance is widely recognized, we do not know much about how much the business cycle influences industry activity. The aim of this paper is to present a method that helps to understand the relationship between the business cycle and an industry's level of activity. Copyright © 2008 John Wiley & Sons, Ltd.
Vertical merger: monopolization for downstream quasi‐rents
Authors: Higgins Richard S.
Published: October 2008

This paper provides a welfare analysis of vertical merger between an input monopolist and downstream firms that compete perfectly in a homogeneous product market. The distinguishing feature of the present model is that the downstream firms face capacity constraints. As a result of downstream quasi‐rents, vertical merger—the extent of merger is gauged by the capacity share of the acquired downstream firm—may either raise or lower final output. An analytical criterion for distinguishing pro‐ and anti‐competitive mergers is derived, which relies entirely on pre‐merger market quantities and the capacity share of the downstream target. A common result is that vertical merger is output‐increasing even when unaffiliated downstream rivals are completely foreclosed. Copyright © 2008 John Wiley & Sons, Ltd.
A complex variable solution for stress and displacement field around a lined circular tunnel at great depth
Authors: Wang Ming‐Bin , Li Shu‐Cai
Published: October 2008

By applying the series expansion technique in the complex variable method established by Muskhelishvili, the plane elasticity problem for the stress and displacement field around a lined circular tunnel in conjunction with the consideration of misfit and interaction between the liner and the surrounding geomaterial is dealt with. The tunnel is assumed to be driven in a homogeneous and isotropic geomaterial. The coefficients in the Laurent series expansion of the stress functions are determined. The complex potentials in the liner and the surrounding geomaterial are explicitly derived, respectively. As an example, the case of a lined circular tunnel located in an isotropic initial stress field but subjected to uniform internal pressure is numerically considered. Numerical results indicate that the installation of tunnel liner can reduce the influences of the tunnel excavation on the in situ displacement and stress fields. However, the relative thickness and rigidity of the liner should be in an appropriate range. In addition, the effect of the tunnel excavation upon the displacement field is more significant than that upon the stress field. As far as the stress field in the surrounding geomaterial is concerned, when the ratio between the cover depth of tunnel and the tunnel radius is larger than 5, the results for the stress field in the paper are applicable. When the ratio between the tunnel depth and the tunnel radius is larger than 20, the results are applicable for the displacement field. Copyright © 2008 John Wiley & Sons, Ltd.
A posteriori error estimation for extended finite elements by an extended global recovery
Authors: Duflot Marc , Bordas Stéphane
Published: October 2008

This contribution presents an extended global derivative recovery for enriched finite element methods (FEMs), such as the extended FEM along with an associated error indicator. Owing to its simplicity, the proposed scheme is ideally suited to industrial applications. The procedure is based on global minimization of the L2 norm of the difference between the raw strain field (C−1) and the recovered (C0) strain field. The methodology engineered in this paper extends the ideas of Oden and Brauchli (Int. J. Numer. Meth. Engng 1971; 3) and Hinton and Campbell (Int. J. Numer. Meth. Engng 1974; 8) by enriching the approximation used for the construction of the recovered derivatives (strains) with the gradients of the functions employed to enrich the approximation employed for the primal unknown (displacements). We show linear elastic fracture mechanics examples, both in simple two‐dimensional settings, and for a three‐dimensional structure. Numerically, we show that the effectivity index of the proposed indicator converges to unity upon mesh refinement. Consequently, the approximate error converges to the exact error, indicating that the error indicator is valid.

Additionally, the numerical examples suggest a novel adaptive strategy for enriched approximations in which the dimensions of the enrichment zone are first increased, before standard h‐ and p‐adaptivities are applied; we suggest to coin this methodology e‐adaptivity. Copyright © 2008 John Wiley & Sons, Ltd.
ℋ︁∞ control of discrete‐time Markov jump systems with bounded transition probabilities
Authors: Boukas E. K.
Published: October 2008

This paper deals with the class of discrete‐time linear systems with random abrupt changes and unknown transition probabilities but varying between known bounds for each mode. The ℋ︁∞ control problem of this class of systems is revisited and new sufficient conditions are developed in the linear matrix inequality (LMI) setting to design the state‐feedback controller that stochastically stabilizes the system under consideration and at the same time guarantees the disturbance rejection with a desired level γ . Sufficient conditions for existence of the state‐feedback controller are developed. It is shown that the addressed problem can be solved if the corresponding developed LMIs are feasible. Numerical examples are employed to show the usefulness of the proposed results. Copyright © 2008 John Wiley & Sons, Ltd.
Why are MSCs therapeutic? New data: new insight
Authors: Caplan AI
Published: October 2008

Adult marrow‐derived mesenchymal stem cells (MSCs) are able to differentiate into bone, cartilage, muscle, marrow stroma, tendon–ligament, fat and other connective tissues. The questions can be asked, what do MSCs do naturally and where is the MSC niche? New insight and clinical experience suggest that MSCs are naturally found as perivascular cells, summarily referred to as pericytes, which are released at sites of injury, where they secrete large quantities of bioactive factors that are both immunomodulatory and trophic. The trophic activity inhibits ischaemia‐caused apoptosis and scarring while stimulating angiogenesis and the mitosis of tissue intrinsic progenitor cells. The immunomodulation inhibits lymphocyte surveillance of the injured tissue, thus preventing autoimmunity, and allows allogeneic MSCs to be used in a variety of clinical situations. Thus, a new, enlightened era of experimentation and clinical trials has been initiated with xenogenic and allogeneic MSCs. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Hypophosphatasia: molecular testing of 19 prenatal cases and discussion about genetic counseling
Authors: Simon‐Bouy Brigitte , Taillandier Agnès , Fauvert Delphine , Brun‐Heath Isabelle , Serre Jean‐Louis , Armengod Carmen G. , Bialer Martin G. , Mathieu Michèle , Cousin Jacques , Chitayat David , Liebelt Jan , Feldman Barbara , Gérard‐Blanluet Marion , Körtge‐Jung Stefani , King Cath , Laivuori Hannele , Le Merrer Martine , Mehta Sarju , Jern Christina , Sharif Saba , Prieur Fabienne , Gillessen‐Kaesbach Gabriele , Zankl Andreas , Mornet Etienne
Published: October 2008

Objective

We studied hypophosphatasia (HP) mutations in 19 cases prenatally detected by ultrasonography without familial history of HP. We correlated the mutations with the reported ultrasound signs, and discussed genetic counseling with regard to the particular dominantly inherited prenatal benign form of HP.

Method

The coding sequence of the tissue nonspecific alkaline phosphatase (TNSALP) gene was analyzed by DNA sequencing, and 3D modeling was used to locate the mutated amino acids with regard to the functional domains of TNSALP.

Results

Although reported ultrasound signs were heterogeneous, two mutated alleles were found in 18 of the 19 cases studied, indicating recessive transmission of the disease. Functional domains of TNSALP were affected by 74% of missense mutations. In all the cases, including one with only a heterozygous mutation, molecular, biological, and familial data do not corroborate the hypothesis of prenatal benign HP. The mutation c.1133A > T observed in the prenatal benign form of HP and common in USA was not found in this series.

Conclusion

The results point out the prenatally detectable allelic heterogeneity of HP. The nature of the detected mutations and the evidence of recessive inheritance do not support these cases being affected with prenatal benign HP. Copyright © 2008 John Wiley & Sons, Ltd.
Reversible photo‐induced spectral change and defect creation in ZrO2
Authors: Fujishiro Fumito , Mochizuki Shosuke
Published: October 2008

When ZrO2 films and nanocrystals are irradiated with a 325 nm laser light in an evacuated chamber, each luminescence‐intensity increases, creating a broad visible luminescence. Then, introducing O2 gas into the specimen chamber, the photoluminescence spectrum returns reversibly to the original luminescence under the same laser light irradiation. After removing the laser light, each luminescence state is stored for a long time at room temperature under room light, regardless of any changes of atmosphere. The observed phenomena are explained by means of the photo‐induced oxygen defect creation and annihilation at/near the ZrO2 surface. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of intra‐chain photoluminescence of a long oligothiophene
Authors: Kanemoto Katsuichi , Akai Ichiro , Hashimoto Hideki , Karasawa Tsutomu , Negishi Nobukazu , Aso Yoshio
Published: October 2008

The temperature dependence (4 K‐300 K) of the photoluminescence (PL) and absorption spectra of 16‐mer oligothiophene (16T) diluted in polypropylene (PP) with a weight ratio of 1/30000 has been investigated in order to clarify the intrinsic temperature effect on conjugated polymers with negligible interchain interaction. The PL and absorption spectra are found to blueshift with increasing temperature. Simple model calculations suggest that the effective conjugation length of 16T is reduced to the two‐third of the original chain length at room temperature. The magnitude of Stokes shift of 16T increases with increasing temperature. The steady‐state PL spectra can be well reproduced by spectral fitting based on Franck‐Condon analysis using a single Huang‐Rhys (HR) factor over the wide temperature range of the measurement. This analysis demonstrates the temperature dependence of HR factor in PL. The HR factor in PL is found to decrease with increasing temperature, whereas that of the absorption spectra increases with temperature. This observation can be explained by assuming that the lowest energy conformer of 16T is responsible for PL and such a conformer has smaller coupling with phonons. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polarization memory effect on nonlinear photoluminescence of semimagnetic semiconductor Cd0.8Mn0.2Te
Authors: Katayama Kouichi , Miyajima Kensuke , Ashida Masaaki , Itoh Tadashi
Published: October 2008

Polarization memory effect was found in the nonlinear photoluminescence band (hereinafter referred to as the X band) of semimagnetic semiconductor Cd0.8Mn0.2Te. The X band appears only when high‐density selective excitation of localized exciton has done. The origin of the X band is proposed as the high‐spin state of the dense magnetic polarons: in this state, every spins of electrons (holes) point one direction and this spin alignment leads to enhanced magnetic polaron effect. The inclusion of linearly polarized component of the X band, which is excited by the linearly polarized excitation laser, is confirmed from the analyzer dependence of the intensity of the X band. The characteristic oscillatory structure of the X band under magnetic field was explained by Faraday rotation of the X band and the structure is reproduced with supposition of step function like absorption. Polarization memory effect of the X band is confirmed by the behavior of the peak energy of the oscillatory structure; the structure varies with tilt of the polarization plane of the excitation laser. The polarization memory effect of the X band most likely originates from the sufficiently long phase relaxation time of the photoexcited electrons and holes of the X band. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parametric interactions and nonlinear Raman processes of vibronic excitons in polydiacetylene studied with a two‐optical‐cycle laser
Authors: Kobayashi Takayoshi , Iwakura Izumi , Yabushita Atsushi
Published: October 2008

Sum and difference frequency mixing, which are the analogues of the second‐order nonlinear optical processes were for the first time found in vibronic exciton systems under high‐density excitations. Cascaded nonlinear Raman scattering was for the first time observed in the exciton system of PDA. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Translation of semiclassical optical‐response theory into quantum‐optics theory
Authors: Koshino Kazuki
Published: October 2008

In order to analyze the dynamics of single photons, a full‐quantum analysis is indispensable in principle, where both the photon field and the material system are treated quantum‐mechanically. However, the semiclassical optical response theory can be utilized to infer the photon dynamics, bypassing the full‐quantum analyses. This fact is demonstrated for a concrete problem of evaluation of the Kerr effect appearing in two photons. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
THz quantum optics with dark excitons in Cu2O: from stimulated emission to nonlinear population control
Authors: Leinß S. , Kampfrath T. , Volkmann K. v. , Schmid B. A. , Fröhlich D. , Wolf M. , Kaindl R. A. , Leitenstorfer A. , Huber R.
Published: October 2008

Fundamental quantum optical processes in photogenerated excitons in Cu2O are demonstrated using few‐cycle terahertz pulses and field‐sensitive electro‐optic sampling: (i) In a dilute ensemble of 3p excitons, stimulated terahertz emission from internal transitions to the energetically lower 2s state is observed at a photon energy of 6.6 meV, with a cross section of 10‐14 cm2. (ii) An optically dark, dense, and cold 1s‐paraexciton gas is prepared by two‐photon generation of electron‐hole pairs and subsequent phonon cooling. Intense multi‐terahertz fields of order MV/cm coherently promote 70% of the quasiparticles from the 1s to the 2p state via a partial internal Rabi oscillation. Electro‐optic detection monitors the Larmor precession of the Bloch vector directly in the time domain, with femtosecond resolution. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Trap state emission of water‐soluble CdS nanocrystals
Authors: Lü W. , Tokuhiro Y. , Umezu I. , Sugimura A. , Nagasaki Y.
Published: October 2008

We prepared water‐soluble CdS nanocrystals (NCs) capped by the poly (ethylene glycol)‐b‐poly (2‐(N,N ‐dimethylamino)ethyl methacrylate) chain. The photoluminescence (PL) properties of CdS NCs are investigated by time‐resolved and temperature‐dependent PL spectra. It is found that the PL band of CdS NCs is dominated by two trap state emissions, respectively. Due to the trap state emissions, fluorescent resonance energy transfer from CdS NCs to organic dyes (Texasred) can be observed, which suggests the potential application of trap states of CdS NCs for fabrication of biosensors. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin orientation of excitons, trions and tetraons in charge tunable InP quantum dots
Authors: Masumoto Yasuaki , Suzuki Tsukasa , Kawana Keisuke , Ikezawa Michio
Published: October 2008

In the longitudinal magnetic field, photoluminescence (PL) polarization in InP quantum dots (QDs) dramatically changed depending on the number of doped electrons. Under linearly polarized excitation, PL polarizes resonantly at two magnetic fields where bright and dark excitons anticross each other in neutral QDs. On the other hand, PL polarization monotonously increases with the increase of longitudinal magnetic field in one‐ and two‐electron doped QDs, where thermal spin orientation of a photoexcited hole determines the PL polarization of a trion and a tetraon. At low temperatures, however, the electron‐hole exchange interaction reduces the thermal spin orientation of holes. In two‐electron doped QDs, the anisotropic electron‐hole exchange interaction gives small structure in the magnetic‐field‐dependent circular polarization at the low field region. Time‐resolved circular polarization clearly shows the dynamical spin polarization process in charged QDs in the longitudinal magnetic field. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extremely long electron spin coherence induced by a trion transition in ZnSe/BeTe type‐II quantum wells
Authors: Mino H. , Kouno Y. , Oto K. , Muro K. , Akimoto R. , Takeyama S.
Published: October 2008

The spin coherence of photoexcited electrons in non‐doped ZnSe/BeTe type‐II quantum wells was investigated by a time‐resolved Kerr rotation (TRKR) technique using resonant excitation of either excitons or negatively charged excitons (trions) in magnetic fields at 1.4 K. The TRKR signal arising from the Lamor precession of photo‐excited electron spins in ZnSe layers was observed and enhanced at the trion resonance, where the spin relaxation time reached up to several nanoseconds. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic‐field induced mixing of singlet and triplet excitons confined in CuCl quantum dots
Authors: Miyajima Kensuke , Umemura Yuna , Katayama Kouichi , Ashida Masaaki , Itoh Tadashi
Published: October 2008

Photoluminescence spectra of CuCl quantum dots and their corresponding decay times have been measured under an external magnetic field in Voigt geometry. Magnetic‐field induced mixing between the singlet and triplet excitons was evaluated by studying the magnetic field dependencies of their decay times. A bound exciton shows a larger degree of mixing than that of a free exciton. In addition, the degree of mixing of the bound exciton increases on decreasing the dot size. It is suggested that the enhancement in the degree of mixing is induced by an increase in the value in the exciton g‐factor due to the symmetry breaking of the wavefunction of the bound exciton. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, characterization, and its PL dynamics of colloidal type II CdTe/CdSe nanocrystals
Authors: Oda Masaru , Nishiyama Akira , Marumo Gi‐ichi , Yamada Shuhei , Tanaka Erina , Tani Toshiro
Published: October 2008

We describe our improved synthesis and optical properties of high quality type II CdTe/CdSe nanocrystals (NCs). Specifically, clear shell‐thickness dependences have been observed in the absorption and photoluminescence (PL) spectra and PL decay profiles as well. The magnitude of the lowest absorption band decreases drastically with large redshift as the shell thickness increases. The origin will be discussed on the bases of the model where the spatial configuration of the lowest electron‐hole pair in the NCs changes from that of type I to type II as the shell thickness increases. As for the PL lifetime of the lowest electron‐hole excitations, substantial increase is observed with increasing shell thickness. This can also be understood by considering the spatial configuration; spatial overlap between electron and hole wavefunctions decreases with increasing shell thickness, thus the lifetime increases. As for the NCs with extremely thin shell (∼1 ML; 1 ML = 0.35 nm), the PL lifetime seems much longer than expected. This suggests that the thin shells seem imperfect and work rather a kind of trap sites than layers. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Are the Chemical Structures in Your QSAR Correct?
Authors: Young Douglas , Martin Todd , Venkatapathy Raghuraman , Harten Paul
Published: October 2008

Quantitative structure–activity relationships (QSARs) are used to predict many different endpoints, utilize hundreds, and even thousands of different parameters (or descriptors), and are created using a variety of approaches. The one thing they all have in common is the assumption that the chemical structures used are correct. This research investigates this assumption by examining six public and private databases that contain structural information for chemicals. Molecular fingerprinting techniques are used to determine the error rates for structures in each of the databases. It was observed that the databases had error rates ranging from 0.1 to 3.4%. A case study to predict the n‐octanol/water partition coefficient was also investigated to highlight the effects of these errors in the predictions of QSARs. In this case study, QSARs were developed using both (i) all correct structures and (ii) structures from a database with an error rate of 3.4%. This case study showed how slight errors in chemical structures, such as misplacing a Cl atom or swapping hydroxy and methoxy functional groups on a multiple ring structure, can result in significant differences in the accuracy of the prediction for those chemicals.
Protein secondary structure class assignment on the basis of a new graphic representation
Authors: Jia Cangzhi , Liu Tian , Zhang Xiangde , Yan Shijun
Published: October 2008

A novel 2D representation (M‐curve) has been provided to visualize the structure information of protein secondary structure sequences: (1) end point of the curve reflects difference of amino acid residue numbers in α‐helices and β‐strands of a protein; (2) Up/down ladder‐like structures in the curve show that α‐helices/β‐strands appear sequentially in this region; (3) triangular‐like/trapeziform‐like structures of the curve show that α‐helices and β‐strands appear alternatively in this region. So from the M‐curve, a protein could be directly assigned into corresponding secondary structure class. Moreover, a new numerical descriptor, four‐component vector, is introduced and applied to cluster analysis. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Integrated approach to PCE‐impacted site characterization, site management, and enhanced bioremediation
Authors: Davis Greg , Baldwin Brett R. , Peacock Aaron D. , Ogles Dora , White Glenn M. , Boyle Susan L. , Raes Eric , Koenigsberg Stephen S. , Sublette Kerry L.
Published: October 2008

Tetrachloroethene (PCE)‐ and trichloroethene (TCE)‐impacted sites pose significant challenges even when site characterization activities indicate that biodegradation has occurred naturally. Although site‐specific, regulatory, and economic factors play roles in the remedy‐selection process, the application of molecular biological tools to the bioremediation field has streamlined the assessment of remedial alternatives and allowed for detailed evaluation of the chosen remedial technology. The case study described here was performed at a PCE‐impacted site at which reductive dechlorination of PCE and TCE had led to accumulation of cis‐dichlorethene (cis‐DCE) with concentrations ranging from approximately 10 to 100 mg/L. Bio‐Trap® samplers and quantitative polymerase chain reaction (qPCR) enumeration of Dehalococcoides spp. were used to evaluate three remedial options: monitored natural attenuation, biostimulation with HRC®, and biostimulation with HRC‐S®. Dehalococcoides populations in HRC‐S‐amended Bio‐Traps deployed in impacted wells were on the order of 103 to 104 cells/bead but were below detection limits in most unamended and HRC‐amended Bio‐Traps. Thus the in situ Bio‐Trap study identified biostimulation with HRC‐S as the recommended approach, which was further evaluated with a pilot study. After the pilot HRC‐S injection, Dehalococcoides populations increased to 106 to 107 cells/bead, and concentrations of cis‐DCE and vinyl chloride decreased with concurrent ethene production. Based on these results, a full‐scale HRC‐S injection was designed and implemented at the site. As with the pilot study, full‐scale HRC‐S injection promoted growth of Dehalococcoides spp. and stimulated reductive dechlorination of the daughter products cis‐DCE and vinyl chloride. © 2008 Wiley Periodicals, Inc.
Early security key exchange for encryption in Mobile IPv6 handoff
Authors: Wu Tin‐Yu , Lo Chi‐Hsiang , Chao Han‐Chieh
Published: October 2008

Wireless equipment has become ubiquitous. However, in facing various software attacks, wireless linked networks are more vulnerable than wire linked networks. The general problem with Mobile IPv6 (MIPv6) (Table I) is the long handover latency period. To reduce the security latency, we propose early security key exchange for encryption in MIPv6 handoff. In our approach, two issues are addressed in dealing with the latency within the encryption technology during the handover. First, we extend the Early Binding Update (EBU) method to deal with the long security exchange negotiation time for the MIPv6 handoff. Second, we adopt the Security Access Gateway (SAG) to solve the limited computing and memory in the Mobile Node (MN). Copyright © 2008 John Wiley & Sons, Ltd.
Social problem solving in chronic fatigue syndrome: preliminary findings
Authors: Christopher Gary , Thomas Marie
Published: October 2008

This paper investigates social problem solving in chronic fatigue syndrome (CFS), a condition characterized by reduced activity levels and excessive mental fatigue. Although intra‐ and inter‐personal problems are prevalent, no studies have explored social problem‐solving skills in this group. Patients were split into two groups: either high or low alexithymia, a condition associated with affect dysregulation. The high alexithymic group viewed problems as threatening, responding either impulsively or avoiding responding altogether; they were poor also in the use of compensatory strategies, which, taken together, increases the likelihood of a negative outcome from attempts at conflict resolution. These findings go some way in successfully identifying potential subgroupings in CFS sufferers and has important implications in terms of the therapy offered. Copyright © 2008 John Wiley & Sons, Ltd.