bluuebunny/crossref_metadata_2025 huggingface dataset:
Cover Picture: White Electroluminescence from a Single‐Polymer System with Simultaneous Two‐Color Emission: Polyfluorene as the Blue Host and a 2,1,3‐Benzothiadiazole Derivative as the Orange Dopant (Adv. Funct. Mater. 7/2006)
Authors: Liu J. , Zhou Q. G. , Cheng Y. X. , Geng Y. H. , Wang L. X. , Ma D. G. , Jing X. B. , Wang F. S.
Published: April 2006

New single‐polymer electroluminescent systems containing two individual emission species—polyfluorenes as a blue host and 2,1,3‐benzothiadiazole derivative units as an orange dopant on the main chain—have been designed and synthesized by Wang and co‐workers on p. 957. The resulting single polymers are found to have highly efficient white electroluminescence with simultaneous blue and orange emission from the corresponding emitting species. A single‐layer device has been fabricated that has performance characteristics roughly comparable to those of organic white‐light‐emitting diodes with multilayer device structures.

New single‐polymer electroluminescent systems containing two individual emission species—polyfluorenes as a blue host and 2,1,3‐benzothiadiazole derivative units as an orange dopant on the main chain—have been designed and synthesized. The resulting single polymers are found to have highly efficient white electroluminescence with simultaneous blue (λmax = 421 nm/445 nm) and orange emission (λmax = 564 nm) from the corresponding emitting species. The influence of the photoluminescence (PL) efficiencies of both the blue and orange species on the electroluminescence (EL) efficiencies of white polymer light‐emitting diodes (PLEDs) based on the single‐polymer systems has been investigated. The introduction of the highly efficient 4,7‐bis(4‐(N‐phenyl‐N‐(4‐methylphenyl)amino)phenyl)‐2,1,3‐benzothiadiazole unit to the main chain of polyfluorene provides significant improvement in EL efficiency. For a single‐layer device fabricated in air (indium tin oxide/poly(3,4‐ethylenedioxythiophene): poly(styrene sulfonic acid/polymer/Ca/Al), pure‐white electroluminescence with Commission Internationale de l'Eclairage (CIE) coordinates of (0.35,0.32), maximum brightness of 12 300 cd m–2, luminance efficiency of 7.30 cd A–1, and power efficiency of 3.34 lm W–1 can be obtained. This device is approximately two times more efficient than that utilizing a single polyfluorene containing 1,8‐naphthalimide moieties, and shows remarkable improvement over the corresponding blend systems in terms of efficiency and color stability. Thermal treatment of the single‐layer device before cathode deposition leads to the further improvement of the device performance, with CIE coordinates of (0.35,0.34), turn‐on voltage of 3.5 V, luminance efficiency of 8.99 cd A–1, power efficiency of 5.75 lm W–1, external quantum efficiency of 3.8 %, and maximum brightness of 12 680 cd m–2. This performance is roughly comparable to that of white organic light‐emitting diodes (WOLEDs) with multilayer device structures and complicated fabrication processes.
Synthesis of bulk MgB2 superconductors by pulsed electric current
Authors: Locci A. M. , Orrù R. , Cao G. , Sanna S. , Congiu F. , Concas G.
Published: April 2006

A preparation method to simultaneously synthesize and consolidate bulk MgB2 superconductors from Mg and B commercial elemental powders by means of the spark plasma sintering technique is reported. The influence of process parameters on sintering process dynamics as well as product characteristics, determined by transport and magnetic measurements, is investigated. The superconducting properties of the obtained samples, and particularly the critical current density, are comparable or better than those corresponding to other MgB2 preparation techniques. Thus, the superconductive properties of the bulk MgB2 materials synthesized in this work are suitable for selected applications, such as magnetic levitation, magnetic screening, and fault current limiters. It should be finally noted that the proposed method represents a particularly rapid preparation route as compared to other techniques. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Hysteresis and its model prediction of electrorheological fluids
Authors: Kim Young Dae , Kee Daniel De
Published: April 2006

Electrorheological (ER) fluids are suspensions of polarizable particles dispersed in insulating liquids. They exhibit a rapid and reversible transition from a liquid‐like to a solid‐like state upon the application of an electric field. The observed shear stress–shear rate hysteresis makes the precise control of the ER mechanical devices very difficult. Hysteresis behavior of TiO2 ER fluids were observed by varying particle concentration, electric field strength, maximum shear rate, and the time of the hysteresis loop. In the absence of an electric field, the stress level of the up curve exceeds that of the down curve. The presence of an electric field reverses this trend. The extent of hysteresis becomes more significant with increasing electric field strength, particle concentration, and maximum shear rate. Hysteresis behavior of TiO2 ER fluids seems to arise mainly due to the change of the particle structure during shearing. To describe the complex rheological behavior of ER fluids, a kinetic theory is presented. Model predictions show qualitative agreement with the experimental hysteresis data. © 2006 American Institute of Chemical Engineers AIChE J, 2006
School fitness tests as predictors of adult health‐related fitness
Authors: Mikkelsson Lasse , Kaprio Jaakko , Kautiainen Hannu , Kujala Urho , Mikkelsson Marja , Nupponen Heimo
Published: April 2006

Relationships between adolescent physical fitness and adult health‐related fitness were investigated. Forty‐five subjects (20 males, 25 females) participated in physical fitness tests in 1976 and again in 2001. The adolescent physical fitness tests were distance running (2,000 m for boys or 1,500 m for girls), 50 m run, pull‐ups (boys) or flexed arm hangs (girls), shuttle run, a 30‐sec sit‐up test, standing broad jump, hand grip‐test, and sit‐and‐reach test. The adult health‐related physical fitness index (APFI), stratified by sex, was formed by summing the z‐scores of a bicycle ergometer test, sit‐up test, hand‐grip test, and sit‐and‐reach test. Height‐ and weight‐adjusted correlations between adolescence and adulthood for exactly similar tests for men and women were, respectively, 0.74 (95% CI, 0.44–0.89) and 0.53 (95% CI, 0.17–0.76) in sit‐and‐reach tests, 0.41 (95% CI, −0.04 to 0.72) and 0.55 (95% CI, 0.20–0.78) in sit‐up tests, and 0.53 (95% CI, 0.11–0.44) and 0.44 (95% CI, 0.05–0.71) in hand‐grip tests. When all adolescent tests were put in regression analysis together with BMI in 2001, the significant explanatory factors for APFI were distance running ability and the sit‐and‐reach test for men and sit‐up test, flexed arm hang, and BMI in 2001 for women. Am. J. Hum. Biol. 18:342–349, 2006. © 2006 Wiley‐Liss, Inc.
High prevalence and phenotype–genotype correlations of limb girdle muscular dystrophy type 2I in Denmark
Authors: Sveen Marie‐Louise , Schwartz Marianne , Vissing John
Published: April 2006

Objectives

The prevalence of limb girdle muscular dystrophy type 2I (LGMD2I) in northern Europe is unknown. We investigated this and the genotype–phenotype relation in LGMD2I.

Methods

Prospective clinical and molecular screening of 118 Danish patients registered with LGMD was performed to divide patients into LGMD subtypes.

Results

One hundred three patients fulfilled the clinical criteria for LGMD2. Thirty‐eight had LGMD2I (27 homozygous, 11 compound heterozygous for 826C>A), 23 had sarcoglycanopathy, 2 dysferlinopathy, 12 calpainopathy, and 4 Becker muscular dystrophy. The 24 patients with no molecular diagnosis did not harbor fukutin‐related protein gene (FKRP) mutations. A clear clinical delineation was found between patients homozygous and compound heterozygous for the 826C>A mutation. Homozygous patients had later debut, milder clinical progression, and less muscle weakness compared with compound heterozygous patients, who were all wheelchair bound by their mid‐20s. Impaired cardiac pump function was found in both groups.

Interpretation

This study reports a different distribution of LGMD subtypes in Denmark than seen in other geographic regions, with a threefold to fourfold higher prevalence of LGMD2I than elsewhere. The findings support a clear clinical delineation between patients homozygous and compound heterozygous for the 826C>A mutation in FKRP. The findings suggest that, in the studied region, screening for the 826C>A mutation will identify all persons with LGMD2I. Ann Neurol 2006;59:808–815
Immune surveillance in multiple sclerosis patients treated with natalizumab
Authors: Stüve Olaf , Marra Christina M. , Jerome Keith R. , Cook Linda , Cravens Petra D. , Cepok Sabine , Frohman Elliot M. , Phillips J. Theodore , Arendt Gabriele , Hemmer Bernhard , Monson Nancy L. , Racke Michael K.
Published: April 2006

Objective

Our objective was to test whether natalizumab, an antibody against very late activating antigen (VLA)‐4, interferes with central nervous system immune surveillance as assessed by leukocyte cell numbers and cellular phenotypes in cerebrospinal fluid (CSF) and peripheral blood.

Methods

Cell numbers and cellular phenotypes in CSF and peripheral blood were analyzed in multiple sclerosis (MS) patients treated with natalizumab, untreated MS patients, and patients with other neurological disease (OND). JC virus DNA in the CSF and peripheral blood was quantified by kinetic polymerase chain reaction.

Results

CSF leukocyte counts, CD4+ and CD8+ T cells, CD19+ B cells, and CD138+ plasma cells were significantly lower in natalizumab‐treated MS patients compared with OND patients and untreated MS patients. JC virus DNA was not detected in CSF or peripheral blood from natalizumab‐treated patients. Six months after cessation of natalizumab therapy, low lymphocyte counts in the CSF persisted. The patient with the highest total leukocyte and CD4+ and CD8+T‐cell counts in the CSF experienced a clinical relapse.

Interpretation

These data suggest that natalizumab treatment results in a prolonged decrease of lymphocytes in the CSF and are consistent with the hypothesis that natalizumab impairs immune surveillance of the central nervous system. Ann Neurol 2006;59:743–747
Natalizumab effects on immune cell responses in multiple sclerosis
Authors: Niino Masaaki , Bodner Caroline , Simard Marie‐Lune , Alatab Sudabeh , Gano Dawn , Kim Ho Jin , Trigueiro Manuela , Racicot Denise , Guérette Christine , Antel Jack P. , Fournier Alyson , Grand'Maison Francois , Bar‐Or Amit
Published: April 2006

Objective

Our objective was to study in vivo biological effects of natalizumab on immune cell phenotype and function in multiple sclerosis (MS) patients.

Methods

Blood was obtained before and after serial monthly natalizumab infusions to track functional expression of VLA‐4 and migratory capacity of immune cells. The impact of infusion on activation thresholds of immune cells was evaluated.

Results

Preinfusion VLA‐4 expression differed across immune cell subsets. Natalizumab significantly, albeit partially, diminished VLA‐4 expression on circulating immune cells. Cell subsets were differentially affected. Treatment significantly decreased migratory capacity of immune cells, correlating well with changes in VLA‐4 expression. Effects of a single dose were not saturating and did not persist through the monthly dose interval. Infusion effect varied across patients but was remarkably stable in individual patients, over multiple infusions. Treatment significantly modulated proliferative responses of immune cells.

Interpretation

To our knowledge, we provide first proof of concept that natalizumab diminishes migratory capacity of immune cells. Our prospective study further shows that effects of therapy likely (1) differ for distinct immune cell subsets, (2) are not sustained over current dose interval, (3) have unique profiles in individual patients, and (4) include modulation of activation threshold of immune cells. Monitoring these parameters could be relevant to ongoing safety and efficacy considerations. Ann Neurol 2006;59:748–754
Cover Picture: Changing the Activity of Electrocatalysts for Oxygen Reduction by Tuning the Surface Electronic Structure (Angew. Chem. Int. Ed. 18/2006)
Authors: Stamenkovic Vojislav , Mun Bongjin Simon , Mayrhofer Karl J. J. , Ross Philip N. , Markovic Nenad M. , Rossmeisl Jan , Greeley Jeff , Nørskov Jens K.
Published: April 2006

Alloying platinum surfaces …︁ …︁ with 3d transition metals makes better cathodes for fuel cells. In their Communication on page 2897 ff., J. K. Nørskov and co‐workers show that this process results in a tuning of the electronic structure of the surface and increases its catalytic activity for the oxygen reduction reaction. The cover picture shows how a wave function involving oxygen p and surface platinum d states in Pt3Co is influenced by cobalt atoms in the second layer.
A transmembrane helix‐bundle from G‐protein coupled receptor CB2: Biosynthesis, purification, and NMR characterization
Authors: Zheng HaiAn , Zhao Ju , Sheng Wanyun , Xie Xiang‐Qun
Published: April 2006

The cannabinoid receptor subtype 2 (CB2) is a member of the G‐protein coupled receptor (GPCR) superfamily. As the relationship between structure and function for this receptor remains poorly understood, the present study was undertaken to characterize the structure of a segment including the first and second transmembrane helix (TM1 and TM2) domains of CB2. To accomplish this, a transmembrane double‐helix bundle from this region was expressed, purified, and characterized by NMR. Milligrams of this hydrophobic fragment of the receptor were biosynthesized using a fusion protein overexpression strategy and purified by affinity chromatography combined with reverse phase HPLC. Chemical and enzymatic cleavage methods were implemented to remove the fusion tag. The resultant recombinant protein samples were analyzed and confirmed by HPLC, mass spectrometry, and circular dichroism (CD). The CD analyses of HPLC‐purified protein in solution and in DPC micelle preparations suggested predominant α‐helical structures under both conditions. The13C/15N double‐labeled protein CB2(27–101) was further verified and analyzed by NMR spectroscopy. Sequential assignment was accomplished for more than 80% of residues. The15N HSQC NMR results show a clear chemical shift dispersion of the amide nitrogen–proton correlation indicative of a pure double‐labeled polypeptide molecule. The results suggest that this method is capable of generating transmembrane helical bundles from GPCRs in quantity and purity sufficient for NMR and other biophysical studies. Therefore, the biosynthesis of GPCR transmembrane helix bundles represents a satisfactory alternative strategy to obtain and assemble NMR structures from recombinant “building blocks.” © 2006 Wiley Periodicals, Inc. Biopolymers 83: 46–61, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Monitoring granule formation in anaerobic upflow bioreactors using oligonucleotide hybridization probes
Authors: Zheng D. , Angenent L.T. , Raskin L.
Published: April 2006

The process of granule formation in upflow anaerobic sludge blanket (UASB) reactors was studied using oligonucleotide hybridization probes. Two laboratory‐scale UASB reactors were inoculated with sieved primary anaerobic digester sludge from a municipal wastewater treatment plant and operated similarly except that reactor G was fed glucose, while reactor GP was fed glucose and propionate. Size measurements of cell aggregates and quantification of different populations of methanogens with membrane hybridization targeting the small‐subunit ribosomal RNA demonstrated that the increase in aggregate size was associated with an increase in the abundance of Methanosaeta concilii in both reactors. In addition, fluorescence in situ hybridization showed that the major cell components of small aggregates collected during the early stages of reactor startup were M. concilii cells. These results indicate that M. concilii filaments act as nuclei for granular development. The increase in aggregate size was greater in reactor GP than in reactor G during the early stages of startup, suggesting that the presence of propionate‐oxidizing syntrophic consortia assisted the formation of granules. The mature granules formed in both reactors exhibited a layered structure with M. concilii dominant in the core, syntrophic consortia adjacent to the core, and filamentous bacteria in the surface layer. The excess of filamentous bacteria caused delay of granulation, which was corrected by increasing shear through an increase of the recycling rate. © 2006 Wiley Periodicals, Inc.
Rapid Room Temperature Buchwald–Hartwig and Suzuki–Miyaura Couplings of Heteroaromatic Compounds Employing Low Catalyst Loadings
Authors: Navarro Oscar , Marion Nicolas , Mei Jianguo , Nolan Steven P.
Published: April 2006

The use of second‐generation [(NHC)Pd(R‐allyl)Cl] complexes for Suzuki–Miyaura and Buchwald–Hartwig cross‐coupling reactions involving heteroaromatic halides at room temperature is reported. The first examples of room temperature Suzuki–Miyaura cross‐coupling of deactivated aryl chlorides with alkenyl boronic acids are also disclosed. Terminal substitution at the allyl moiety of the palladium complex facilitates its activation at room temperature leading to very active catalytic species enabling the present catalytic transformations to be performed rapidly using very mild reaction conditions. Catalyst loadings can be as low as 10 ppm for the Buchwald–Hartwig aryl amination and 50 ppm for the Suzuki–Miyaura reaction.
Binge eating and purging in a multi‐ethnic community sample
Authors: Regan Pamela C. , Cachelin Fary M.
Published: April 2006

Objective:

The purpose of the present study is to document the frequency of three eating disorder‐related behaviors (binge eating; self‐induced vomiting; and use of laxatives, diuretics, and diet pills) among a multi‐ethnic community sample.

Method:

A questionnaire was administered to 1225 Hispanic, Asian, black, and white women and men. Participants responded to items (based on DSM‐IV diagnostic criteria for eating disorders) about binge eating and purging behavior.

Results:

Binge eating and purging were more common among women than among men in Hispanic, black, and white subsamples (frequency rates were similar among Asian men and women). Ethnic differences were found in frequency of purging among women (ethnicity was not associated with behavior rates among men). Fewer Asian than Hispanic, black, and white women induced vomiting and used laxatives, diuretics, and diet pills as weight control methods.

Conclusion:

The fact that frequency rates differed as a function of participant sex and ethnicity underscores the importance of considering both of these group variables when examining disordered eating and weight control behaviors. © 2006 by Wiley Periodicals, Inc. Int J Eat Disord 2006
Cohabitation reduces bulimic symptoms in young women
Authors: von Soest Tilmann , Wichstrøm Lars
Published: April 2006

Objective:

This current study examines the relationship between cohabitation and changes in bulimic symptoms in young adults.

Method:

A sample of 2601 initially noncohabitating adolescents was followed over a 5‐year period and growth curve analyses were conducted.

Results:

Females who over the course of the study moved in with a partner had greater decreases in bulimic symptoms compared with female noncohabitators. This difference was highly significant, even if small in size. No such effect was found in males. When examining the frequency of bulimic behaviors in females, the most socially unacceptable bulimic behaviors were those most reduced by cohabitation, whereas less obtrusive bulimic behaviors were not reduced.

Conclusion:

The results give some indication that social control exercised in close relationships may account for decreased bulimic symptoms in female cohabitators. Further studies are needed to confirm the importance of social control and to examine how it affects symptom reduction. © 2006 by Wiley Periodicals, Inc. Int J Eat Disord 2006
Sexual orientation as a risk factor for bulimic symptoms
Authors: Wichstrøm Lars
Published: April 2006

Objective:

This study was carried out to examine whether sexual orientation predicts future bulimic symptoms and whether alleged risk factors associated with non‐heterosexual sexual orientation explain the increased risk.

Method:

A nationally representative sample of Norwegian high school students (age 14–19; N = 2,924) completed self‐reports about bulimic symptoms by means of the Bulimic Investigatory Test–Edinborough (BITE), same‐sex sexual experience, degree of sexual attraction to the same sex, and alleged risk factors. They were reexamined 5 years later (T2).

Results:

Same‐sex sexual experience before T1 increased the prevalence of bulimic symptoms at T2. Males who were attracted to the same sex at T1 had higher odds for bulimic symptoms compared with heterosexual males. These associations were still significant after controlling for initial bulimic symptoms and alleged risk factors.

Conclusion:

Same‐sex sexual experience in both genders and non‐heterosexual sexual attraction among males predict future bulimic symptoms. Commonly advocated explanations for this elevated risk were not supported. © 2006 by Wiley Periodicals, Inc. Int J Eat Disord 2006
New Cycloadditions of (E)‐N,α‐Dimethyl‐α‐(4‐[2.2]paracylophanyl)nitrone
Authors: Aly Ashraf A. , Hopf Henning , Ernst Ludger , Dix Ina , Jones Peter G.
Published: April 2006

When N,α‐dimethyl‐α‐(4‐[2.2]paracyclophanyl)nitrone (1) is treated with dimethyl acetylenedicarboxylate (5), phenyl isocyanate (9), benzyne (13), or ethyl propiolate (16), the [2.2]paracyclophane‐based pyrrole 6, imidazole 10, and isoxazole derivatives 14, 15, and 17 are formed in good yields. The stereoisomeric benzisoxazoles 14 and 15 obtained from the reaction between 1 and benzyne (13) could be separated and the structure of one of these stereoisomers, 15, was assigned by X‐ray structural analysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Hypoosmolar conditions reduce extracellular volume fraction and enhance epileptiform activity in the CA3 region of the immature rat hippocampus
Authors: Kilb Werner , Dierkes Paul W. , Syková Eva , Vargová Lydia , Luhmann Heiko J.
Published: April 2006

The osmolarity of the extracellular space (ECS) compartment is an important factor determining the excitability of neuronal tissue. In the adult hippocampus an important role of osmolarity and ECS diffusion parameters on the susceptibility to epileptic events is well established, but the influence of hypo‐ and hyperosmolar conditions on the immature hippocampus remains elusive. To investigate the influence of osmolarity on epileptiform activity, extracellular field potentials were recorded in the CA3 region of hippocampal slices of immature (postnatal days 4–7) Wistar rats. The ECS diffusion parameters were determined by the real‐time tetramethylammonium (TMA+) iontophoretic method with ion‐selective microelectrodes in immature hippocampal slices and showed a lack of diffusion anisotropy; a tortuosity of about 1.39; and a volume fraction, α, of 0.41 ± 0.01 (n = 10 slices). A reduction in osmolarity of –90 mOsm induced a decrease in α to 0.17 ± 0.02 (n = 4 slices). The frequency of epileptiform activity elicited in 10–50 μM 4‐AP‐containing low‐Mg2+ solution was increased under –90 mOsm and –40 mOsm hypoosmolar conditions by 39.9% ± 8.1% (n = 16) and 24.1% ± 4.8% (n = 10), respectively, whereas hyperosmolar solutions decreased the frequency. A –90‐mOsm reduction in the osmolarity of low‐Mg2+ solution induced epileptiform activity in nine of 19 slices. In summary, these results demonstrate that hypoosmolar conditions increased excitability and susceptibility to epileptiform activity in immature hippocampal slices, suggesting a functional role of the larger α in suppression of seizures. © 2006 Wiley‐Liss, Inc.
Reactions of the activated, rigid, α‐diazomethine group of 1,2,5‐thiadiazole 1,1‐dioxides with nitrogenated nucleophiles. Part III: aliphatic monoamines and phenylhydrazine
Authors: Caram José Alberto , Piro Oscar Enrique , Castellano Eduardo Ernesto , Mirífico María Virginia , Vasini Enrique Julio
Published: April 2006

The reactions of n‐butylamine (BuNH2), 2‐aminoethanol (H2N(CH2)2OH), diethylamine (Et2NH), and phenylhydrazine (PhN2H3) with 3,4‐diphenyl‐(1a) and phenanthro[9,10‐c]‐1,2,5‐thiadiazole 1,1‐dioxide (1b) were studied by cyclic voltammetry (CV) and 1H‐ and 13C‐NMR in aprotic solvent solution. The course of the reactions depended on the substrate‐nucleophile combination: Et2NH added to 1a or 1b, forming the corresponding thiadiazolines in an equilibrium monoaddition reaction. The equilibrium constants were evaluated and compared. With primary amines and PhN2H3, the nucleophile added to both CN double bonds of 1a and displaced the sulfamide moiety. In the case of the reaction of 1a with PhN2H3, the intermediate monoaddition thiadiazoline, 3‐(2‐phenylhydrazino)‐3,4‐diphenyl‐1,2,5‐thiadiazoline 1,1‐dioxide, was also isolated. BuNH2 and H2N(CH2)2OH reacted with 1a to give α‐bis‐imines, while 1a with PhN2H3 gave the α‐bis‐hydrazone. The configurations of benzil bis(ethanolimine) and benzilosazone were determined by single crystal x‐ray diffraction analysis as Z,Z. BuNH2 and PhN2H3 reduced 1b to the corresponding thiadiazoline compound 1bH2. Copyright © 2006 John Wiley & Sons, Ltd.
High‐speed topic organizer of TV shows using video dialog detection
Authors: Aoki Hisashi
Published: April 2006

Recently, due to the rapid spread of digital video recorders capable of storing a large number of TV programs, there is a great need for easy interfaces for viewing program content and for accessing scenes of interest. To provide such functions, it is necessary and effective to segment a recorded TV program into temporal sections according to the content structure. However, in conventional approaches such as cut‐detection methods, content is chopped up into segments that are too short, and the computational costs of intelligent recognition methods for speech, face, and text are prohibitive in many cases. The author has developed a light and high‐speed algorithm which estimates the structure of video content and completes temporal segmentation instantly after the recording. The proposed method introduces a measurement which denotes the likelihood of a given temporal part of a recorded TV program being a dialog scene, according to the appearances of similar shots. With this measurement, related consecutive shots are determined as being in a dialog scene, and consequently topics in a news program and sections in a variety show are effectively estimated. In this paper, the author discusses development, implementation, and effectiveness of the system which provides automatic segmentation of a variety of recorded TV programs, applying the proposed method. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(6): 44–54, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20438
Determination of object shape and reflectance based on Moiré system using multiple light sources and a reflection model
Authors: Naganuma Shoichi , Tagawa Norio , Minagawa Akihiro , Moriya Tadashi
Published: April 2006

A method for determining the three‐dimensional shape and surface reflectance of an object from images is presented. The method is based on a combination of Moiré analysis and a reflection model, and is defined for objects with reflectance formulated using Phong's reflection model. Objects are regarded as consisting of multiple surfaces, each with specific and uniform reflectance, and the number of regions is assumed to be known for simplicity. The proposed method overcomes two problems in reflectance estimation: ambiguity of reflectance due to the relationship between the surface normal and the components of diffuse and specular reflectance, and the lack of reflectance information for pixels with zero intensity due to the grating pattern employed for Moiré analysis. Using multiple light sources, multiple images with shifted grating phase are captured and analyzed for Moiré analysis. The method is confirmed through numerical simulations and experiments to obtain accurate shape and reflectance information, with a significant improvement over existing image‐based methods. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(6): 32–43, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20442
Blind dereverberation of monaural speech signals based on harmonic structure
Authors: Nakatani Tomohiro , Miyoshi Masato , Kinoshita Keisuke
Published: April 2006

This paper presents a new method for dereverberating monaural speech signals. Speech signals captured by a distant microphone usually contain a lot of reverberation, which severely degrades the performance of speech applications such as automatic speech recognition (ASR) systems. Although a number of dereverberation methods have been proposed, dereverberation remains a challenging problem, especially when using a single microphone. To overcome this problem, we propose a dereverberation method based on an inherent property of speech signals, namely, their harmonic structure. We show that a filter that enhances the harmonic structure of reverberant speech signals approximates an inverse filter of the reverberation process, and can achieve high‐quality speech dereverberation. Experimental results show that a dereverberation filter trained with a sufficient amount of observed reverberant signals can effectively reduce the signal reverberation when the reverberation time is 0.1 to 1.0 s. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(6): 1–12, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20509
Transabdominal Gastro‐esophageal Devascularization and Esophageal Transection for Bleeding Esophageal Varices after Failed Injection Sclerotherapy: Long‐Term Follow‐Up Report
Authors: Qazi Shabir Ahmad , Khalid Kamran , Hameed Abdul Majeed Abdul , Al‐Wahabi Khalid , Galul Radwan , Al‐Salamah Saleh M.
Published: April 2006

Background

Management of continued bleeding from esophageal varices despite adequate injection sclerotherapy remains one of the medical and surgical dilemmas. Transabdominal gastroesophageal devascularization and esophageal transection (TGDET) is considered an effective and safe procedure for such patients.

Aim

This study aimed at presenting continued evaluation of TGDET. Various problems influencing the early outcome are discussed, and long‐term outcome is analyzed.

Design

This was a prospective clinical descriptive study.

Methods

Prospective data was collected on 142 consecutive patients managed by one group of surgeons over a 5 year‐period and 15 years follow‐up after failed injection sclerotherapy for variceal bleeding. Evaluation was made in terms of effectiveness in controlling the acute bleeding, postoperative morbidity and mortality, recurrent bleeding, encephalopathy, and long‐term survival.

Results

There were 133 men and 9 women. Mean age was 41.8 years. Etiology of portal hypertension was bilharziasis in 54.9% and posthepatitic in 14.8%. Child–Pugh grading on admission was A: 47.2%, B: 28.8%, and C: 14%. Hemorrhage was controlled in all cases. Clinical leak was observed in 5.6%, portal vein thrombosis in 6.3%, and staple line erosion in 2.1% of cases. No patient developed encephalopathy. In‐hospital mortality was 12.7%. Complete eradication of varices was observed in 70.6% patients. Recurrent variceal bleeding was noticed in 6.9% of cases. Actuarial 15‐year survival for Child–Pugh A patients was 44%, B was 22.5%, and none for C.

Conclusion

TGDET remains a safe and effective procedure after failure of sclerotherapy when other alternatives are either not indicated or not available.
Evaluation of the basic systems of equations for turbulence measurements using the Monte Carlo technique
Authors: Swaminathan M. K. , Rankin G. W. , Sridhar K.
Published: April 2006

A numerical experiment has been carried out to evaluate two of the methods available for finding the time-averaged mean velocity and the Reynolds stresses of a turbulent flow field using hot wires. The conventional method is based on the series expansion of the response equation, subsequent truncation of the series and time averaging. The improved method is based on squaring and time averaging without neglecting any terms. The method adopted to evaluate these two methods is based on the Monte Carlo simulation of a pseudo turbulent flow field using random-number generators and the corresponding hot-wire response, for a prescribed set of conditions, by assuming an appropriate model for the hot-wire response. The simulated hot-wire response and the calibration constants are then perturbed about their mean values to study the effects of errors in these quantities. The perturbed response is used to compute the time-averaged flow field by the two methods. The deviation of these values from the generated pseudo values, averaged over large number of trials, is used as the criterion to evaluate the methods. This procedure is also used to estimate the errors due to truncation in the conventional method, to study the effect of turbulence-intensity levels and to study the effects of measurement errors. The results indicate that the choice of the method for determining the time-averaged quantities should be based on the turbulence-intensity level and the measurement errors likely to be encountered. The conventional method yields reliable mean-velocity results for turbulence intensities as high as 50% with second-order turbulence correction. If measurement errors are within reasonable limits and the turbulence level is below 20%, the conventional method yields reliable results for Reynolds stresses. The improved method should be used to determine the time-averaged flow field for turbulence intensity above 40–50%. The error in the yaw sensitivity parameter k has an insignificant effect on the mean velocity and Reynolds stresses computed by both methods. By accurately determining the sensitivity s of the hot wire, the accuracy of the measured mean velocity and Reynolds stresses can be improved significantly. An improved method of carrying out the uncertainty analysis for measurements, based on the Monte Carlo technique, has also been outlined.
On transition of the pulsatile pipe flow
Authors: Stettler J. C. , Hussain A. K. M. Fazle
Published: April 2006

Transition in a pipe flow with a superimposed sinusoidal modulation has been studied in a straight circular water pipe using laser-Doppler anemometer (LDA) techniques. This study has determined the stability–transition boundary in the three-dimensional parameter space defined by the mean and modulation Reynolds numbers Rem, Remω and the frequency parameter λ. Furthermore, it documents the mean passage frequency Fp of ‘turbulent plugs’ as functions of Rem’ Remω and λ. This study also delineates the conditions when plugs occur randomly in time (as in the steady flow) or phase-locked with the excitation. The periodic flow requires a new definition of the transitional Reynolds number Rer, identified on the basis of the rate of change of Fp with Rem. The extent of increase or decrease in Rer from the corresponding steady flow value depends on λ and Remω. At any Rem and Remω, maximum stabilization occurs at λ ≈ 5. With increasing Remω, the ‘stabilization bandwidth’ of modulation frequencies increases and then abruptly decreases after levelling off. The maximum stabilization bandwidth depends strongly on Rem, decreasing with increasing Rem. Previously reported observations of turbulence during deceleration, followed by a relaminarization during acceleration, can be explained in terms of a new phenomenon: namely, periodic modulation produces longitudinally periodic cells of turbulent fluid ‘plugs’ which differ in structural details from ‘puffs’ or ‘slugs’ in steady transitional pipe flows and are called patches. The length of a patch could be increased continuously from zero to the entire pipe length by increasing Rem. This tends to question the concept that all turbulent plugs (and even the fully-turbulent pipe flow) consists of many identical elementary plugs as basic ‘building blocks’.
Spatially amplifying modes of the Charney baroclinic-instability problem
Authors: Pierrehumbert R. T.
Published: April 2006

We determine the circumstances under which baroclinic instability in the Charney model subjected to localized time-periodic forcing manifests itself as a wavetrain that oscillates at the source frequency and amplifies in space with distance from the source; analytical and numerical results describing the salient characteristics of such waves are presented. The spatially amplifying disturbance is a hitherto unsuspected part of the response to a pulsating source, and coexists with the more familiar neutral Rossby wavetrains; it is likely to play a role in a wide range of atmospheric and oceanic phenomena.

The central results rely on a careful application of a causality criterion due to Briggs. These results illustrate a practical means of attacking spatial instability problems, which can be applied to a broad class of systems besides the one at hand. We have found that the Charney problem with positive vertical shear is not absolutely unstable, so long as the wind at the ground is non-negative. This implies that spatial instability and forced stationary-wave problems are well posed in an open domain under typical atmospheric circumstances.

The amplifying waves appear on the downstream side of the source, have eastward (downstream) phase propagation and have wavelengths that increase monotonically with decreasing frequency, becoming infinite at zero frequency. When the surface wind is not too large, the spatial amplification rate has a single maximum near the frequency ωm= (f/N)Uz, wherefis the Coriolis parameter,Nis the stability frequency andUzis the vertical shear; the rate approaches zero at zero frequency and asymptotes algebraically to zero at large frequency for any positive surface wind. Distinct Charney and Green modes do not appear until the surface wind is made very large. The amplification rate at ωmbecomes infinite as surface wind approaches zero, suggesting a mechanism for the concentration of eddy activity.

We also discuss the relationship of these results to the structure of low- and high-frequency atmospheric variability.
Streamwise vortex structure in plane mixing layers
Authors: Bernal L. P. , Roshko A.
Published: April 2006

The development of three-dimensional motions in a plane mixing layer was investigated experimentally. It is shown that superimposed on the primary, spanwise vortex structure there is a secondary, steamwise vortex structure. Three aspects of this secondary structure were studied. First, the spanwise vortex instability that generates the secondary structure was characterized by measurements of the critical Reynolds number and the spanwise wavelength at several flow conditions. While the critical Reynolds number was found to depend on the velocity ratio, density ratio and initial shear-layer-profile shape, the mean normalized wavelength is independent of these parameters. Secondly, flow visualization in water was used to obtain cross-sectional views of the secondary structure associated with the streamwise counter-rotating vortices. A model is proposed in which those vortices are part of a single vortex line winding back and forth between the high-speed side of a primary vortex and the low-speed side of the following one. Finally, the effect of the secondary structure on the spanwise concentration field was measured in a helium–nitrogen mixing layer. The spatial organization of the secondary structure produces a well-defined spanwise entrainment pattern in which fluid from each stream is preferentially entrained at different spanwise locations. These measurements show that the spanwise scale of the secondary structure increases with downstream distance.
The numerical experiment in fluid mechanics
Authors: Aref Hassan
Published: April 2006

Several aspects of the use of digital computers to generate solutions of equations of interest to fluid mechanics are discussed. The inter-disciplinary nature of the field of computational fluid dynamics (CFD) is emphasized: the dependence on strides in computer technology, the impact of advances in algorithm development, the continuous interaction with laboratory experiment and analytical theory. The particular role of that mode of computer usage usually referred to as the numerical experiment is highlighted. ‘Experiments’ of this type have played a central role in establishing concepts such as the soliton and the strange attractor as paradigms within fluid mechanics. The ambitious goal of providing digital counterparts to laboratory equipment such as the wind tunnel is considered. The possibility of abandoning the Eulerian representation of flow fields in favour of following swarms of Lagrangian particles on a computer is stressed. Issues arising from and results of using this methodology are reviewed. Computer simulations are contrasted with computer generated animation. The paper concludes with speculations on future developments.
An experimental study of transient effects in the breakup of viscous drops
Authors: Stone H. A. , Bentley B. J. , Leal L. G.
Published: April 2006

A computer-controlled four-roll mill is used to examine two transient modes of deformation of a liquid drop: elongation in a steady flow and interfacial-tension-driven motion which occurs after the flow is stopped abruptly. For modest extensions, drop breakup does not occur with the flow on, but may occur following cessation of the flow as a result of deterministic motions associated with internal pressure gradients established by capillary forces. These relaxation and breakup phenomena depend on the initial drop shape and the relative viscosities of the two fluids. Capillary-wave instabilities at the fluid-fluid interface are observed only for highly elongated drops. This study is a natural extension of G. I. Taylor's original studies of the deformation and burst of droplets in well-defined flow fields.
Experiments with baroclinic vortex pairs in a rotating fluid
Authors: Griffiths R. W. , Hopfinger E. J.
Published: April 2006

When vortices are generated in one layer of a rotating, two-layer density stratification, the velocity field of each vortex is strongly baroclinic within a distance of order one Rossby radius from its centre. In this system there are two classes of vortex pairs: those pairs (consisting of vortices of opposite signs) for which the vortices are in the same layer, and those for which the vortices are in opposite layers. We pay particular attention to a laboratory demonstration of the properties of the latter class. These vortex pairs have the ability to transport density (or heat) in the horizontal, and provide a means for describing the release of potential energy by baroclinic instability. We also observe that interactions of real vortices and real vortex pairs differ from those computed for point vortices.
Asymptotic theory of convection in a rotating, cylindrical annulus
Authors: Busse F. H.
Published: April 2006

The problem of convection in a rotating cylindrical annulus heated from the outside and cooled from the inside is considered in the limit of high rotation rates. The constraint of rotation enforces the two-dimensional character of the motion when the angle of inclination of the axisymmetric end surfaces with respect to the equatorial plane is small. Even when the angle of inclination is large only the dependences on the radial and the azimuthal coordinates need to be considered. The dependence on time at the onset of convection is similar to that of Rossby waves. But at higher Rayleigh numbers a transition to vacillating solutions occurs. In the limit of high rotation rates simple equations can be derived which permit the reproduction and extension of previous numerical results.
The motion of a viscous drop sliding down a Hele-Shaw cell
Authors: Jansons Kalvis M.
Published: April 2006

The motion of a viscous drop in a vertical Hele-Shaw cell is studied in a limit where the effect of surface tension through contact-angle hysteresis is significant. It is found that a rectangular drop shape is a possible steady solution of the governing equations, although this solution is unstable to perturbations on the leading edge. Even though the unstable edge is one where a viscous fluid is moving into a less viscous fluid, in this case air, this is shown to be a special case of the well-known Saffman—Taylor instability. An experiment is performed with an initially circular drop in which it is observed that the drop shape becomes approximately rectangular except at the leading edge, where it becomes rounded and sometimes has a ragged appearance.

A drop sliding down a vertical Hele-Shaw cell is an example of a system where the action of surface tension is not always one of smoothing, since in this case it leads to the formation of right-angle corners at the back of the drop (rounded only slightly on the lengthscale of the gap thickness of the cell).
An exact solution of the Navier-Stokes equation which describes non-orthogonal stagnation-point flow in two dimensions
Authors: Dorrepaal J. M.
Published: April 2006

A similarity solution is found which describes the flow impinging on a flat wall at an arbitrary angle of incidence. The technique is similar to a method used by Jeffery (1915) and discussed more recently by Peregrine (1981).
Numerical simulation of the aα-effect and turbulent magnetic diffusion with molecular diffusivity
Authors: Drummond I. T. , Morgan R. R.
Published: April 2006

We extend the numerical methods of a previous paper to the study of the α-effect in a turbulent plasma. In the frozen-turbulence case the α-effect vanishes for zero molecular diffusivity. The value of α is, however, found to depend very sensitively on the molecular diffusivity. The same is true for the turbulent magnetic diffusivity β. The theoretical predictions of the first-order smoothing and the Markovian approximations are well satisfied in the appropriate limits, for both α and β.
The elastohydrodynamic collision of two spheres
Authors: Davis Robert H. , Serayssol Jean-Marc , Hinch E. J.
Published: April 2006

The dynamic deformation of a solid elastic sphere which is immersed in a viscous fluid and in close motion toward another sphere or a plane solid surface is presented. The deformed shape of the solid surfaces and the pressure profile in the fluid layer separating these surfaces are determined simultaneously via asymptotic and numerical techniques. This research provides the first steps in establishing rational criteria for predicting whether a solid particle will stick or rebound subsequent to impact during filtration or coagulation when viscous forces are important.