bluuebunny/crossref_metadata_2025 huggingface dataset:
Bayes-optimal solution to inverse halftoning based on statistical mechanics of the Q-Ising model
Authors: Saika Yohei , Inoue Jun-ichi , Tanaka Hiroyuki , Okada Masato
Published: May 2009

On the basis of statistical mechanics of the Q-Ising model, we formulate the Bayesian inference to the problem of inverse halftoning, which is the inverse process of representing gray-scales in images by means of black and white dots. Using Monte Carlo simulations, we investigate statistical properties of the inverse process, especially, we reveal the condition of the Bayes-optimal solution for which the mean-square error takes its minimum. The numerical result is qualitatively confirmed by analysis of the infinite-range model. As demonstrations of our approach, we apply the method to retrieve a grayscale image, such as standard image Lena, from the halftoned version. We find that the Bayes-optimal solution gives a fine restored grayscale image which is very close to the original. In addition, based on statistical mechanics of the Q-Ising model, we are sucessful in constructing a practically useful method of inverse halftoning using the Bethe approximation.
Chemical evaluation of seeded fruit biomass of oil pumpkin (Cucurbita pepo L. var. Styriaca)
Authors: Košťálová Zuzana , Hromádková Zdenka , Ebringerová Anna
Published: May 2009

Oil pumpkin (Cucurbita pepo L. var. Styriaca) is an economically important horticultural plant cultivated for oil production. After harvesting seeds, the residual biomass has a limited application and is usually left in the field. An experimental study was performed to evaluate the chemical composition of the seeded fruit oil pumpkin biomass (OP) dried by solvent-exchange using ethanol. The sugar composition of polysaccharides obtained by sequential extraction with water and dilute alkali indicated the prevalence of pectic polysaccharides. Hemicelulloses were released in higher amounts in the alkaline step. The chemical composition of OP and its individual tissues (peel, flesh and hairy flesh) was investigated and compared to the corresponding preparations of standard pumpkin (SP, Cucurbita pepo L.). The content of components (on oven-dry basis), calculated from the analysis data of the individual tissues, was estimated for OP: 7.9 % ash, 7.6 % Klason lignin, 19.3 % pectin (as uronic acids), 34.1 % neutral carbohydrates, and 27.4 % α-cellulose and for SP: 6.4 % ash, 4.0 % Klason lignin, 20.9% pectin (as uronic acids), 38.1% neutral carbohydrates, and 29.2 % α-cellulose, respectively. The OP biomass showed a higher proportion of hemicelluloses.
Immobilization of porphyrins in poly(hydroxymethylsiloxane)
Authors: Šabata Stanislav , Hetflejš Jiří , Rychtáriková Renata , Kuncová Gabriela , Lang Kamil , Kubát Pavel
Published: May 2009

Three tetracationic porphyrins differing in the position of charged nitrogen atoms on the peripheral substituents — 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP4), 5,10,15,20-tetrakis(N-methylpyridinium-2-yl)porphyrin (TMPyP2), 5,10,15,20-tetrakis(4-trimethylammoniophenyl) porphyrin (TMAPP), and hydrophobic 5,10,15,20-tetraphenylporphyrin (TPP), were immobilized by adsorption and encapsulation in poly(hydroxymethylsiloxane) (PHOMS). The so prepared porphyrin-PHOMS composites were characterized by porosimetry, scanning electron microscopy, fluorescence and diffuse reflectance UV-VIS spectroscopy. It was found that porphyrins are immobilized in the PHOMS matrix in the free base monomer form Their irradiation produced singlet oxygen O2(1Δg) with the lifetime of 10–30 μs.
Coupling of Two Partial Differential Equations and its Application, II — the Case of Briot–Bouquet Type PDEs —
Authors: Tahara Hidetoshi
Published: May 2009

Let

F(t, x, u,v)

be a holomorphic function in a neighborhood of the origin of

ℂ^4

satisfying

F(0, x, 0, 0) ≡ 0

and

(∂F/∂v)(0,x, 0, 0) ≡ 0

; then the equation (A)

t∂u/∂t= F(t,x,u,∂u/∂x)

is called a Briot–Bouquet type partial differential equation, and the function

λ(x) = (∂F/∂u)(0,x, 0, 0)

is called the characteristic exponent. This paper considers a reduction of this equation (A) to a simple form (B) 

t∂w/∂t = λ(x)w

under the assumption

λ(0) ∉ (−∞, 0]∪\{1, 2, . . .\}

. The reduction is done by considering the coupling of two equations (A) and (B), and by solving their coupling equations. The result is applied to the problem of finding all the singular solutions of (A).
Homogenized Spectral Problems for Exactly Solvable Operators: Asymptotics of Polynomial Eigenfunctions
Authors: Borcea Julius , Bøgvad Rikard , Shapiro Boris
Published: May 2009

Consider a homogenized spectral pencil of exactly solvable linear differential operators

T_λ = \sum^k_{i=0} Q_i(z)λ^{k−i} \frac{d^i}{dz^i}

, where each 

Q_i(z)

is a polynomial of degree at most

i

and

λ

is the spectral parameter. We show that under mild nondegeneracy assumptions for all sufficiently large positive integers

n

there exist exactly

k

distinct values

λ_{n,j}

,

1 ≤ j ≤ k

, of the spectral parameter

λ

such that the operator

T_λ

has a polynomial eigenfunction

p_{n,j}(z)

of degree

n

. These eigenfunctions split into

k

different families according to the asymptotic behavior of their eigenvalues. We conjecture and prove sequential versions of three fundamental properties: the limits

Ψ_j (z) = \lim_{n→∞} \frac{p'_{n,j}(z)}{λ_{n,j}p_{n,j}(z)}

exist, are analytic and satisfy the algebraic equation

\sum^k_{i=0} Qi(z)Ψ^i_j(z) = 0

almost everywhere in

ℂ ℙ^1

. As a consequence we obtain a class of algebraic functions possessing a branch near

∞ ∈ ℂ ℙ^1

which is representable as the Cauchy transform of a compactly supported probability measure.
The Essential Spectrum of the Laplacian on Manifolds with Ends
Authors: Hattori Toshiaki
Published: May 2009

Let
V
be a noncompact complete Riemannian manifold. We find a geometric condition which assures that the essential spectrum of the Laplacian on
V
contains a half-line, by means of fiber bundle structures and the asymptotic behavior of mean curvatures on the ends of
V
, and give lower bounds of the essential spectrum. Our criteria can be applied to locally symmetric spaces of finite volume and manifolds of infinite volume canonically obtained from manifolds with corners.
Intersection Homology $\mathcal D$-Module and Bernstein Polynomials Associated with a Complete Intersection
Authors: Torrelli Tristan
Published: May 2009

Let

X

be a complex analytic manifold. Given a closed subspace

Y\subset X

of pure codimension

p ≥ 1

, we consider the sheaf of local algebraic cohomology

H^p_{[Y]}(\mathcal O_X)

, and

\mathcal L(Y,X)\subset H^p_{[Y ]}(\mathcal O_X)

the intersection homology 

\mathcal D_X

-Module of Brylinski–Kashiwara. We give here an algebraic characterization of the spaces

Y

such that

\mathcal L(Y,X)

coincides with 

H^p_{[Y]}(\mathcal O_X)

, in terms of Bernstein–Sato functional equations.
Causas y factores posibilitadores del proceso migratorio en el discurso de los emigrantes: Gallegos en Cuba en la primera mitad del siglo XX
Authors: Vidal Rodríguez José Antonio
Published: May 2009

En este artículo intento destacar, basándome en diferentes tratadistas de los siglos XIX y XX y en testimonios orales recogidos en Cuba, cómo además de las causas económicas actuaron también, y con frecuencia decisivamente, otros factores de tipo psicosocial en la decisión migratoria de muchos de los gallegos que emigraron a Cuba, sin los cuales, probablemente, nunca se hubiesen decidido a abandonar sus hogares. Hecho que bien se podría hacer extensivo a los demás procesos migratorios de otras regiones de España durante el período de emigración masiva de españoles hacia América.
El asociacionismo inmigratorio español en Uruguay en la mira del franquismo: entre la oposición y el disciplinamiento
Authors: Zubillaga Carlos
Published: May 2009

Se analiza la emergencia del asociacionismo español en Uruguay y la evolución de sus relaciones con el gobierno peninsular, particularmente en el contexto de la guerra civil y del régimen franquista. La información producida por la representación diplomática española en Montevideo se complementa con la prédica «hispanista» en libros y revistas editados en el seno de la colectividad inmigrada, tendente a la constitución de estructuras de disciplinamiento político e ideológico.
Entre dos exilios: Cesare Civita, un editor italiano en Buenos Aires, desde la guerra mundial hasta la dictadura militar (1941- 1976)
Authors: Scarzanella Eugenia
Published: May 2009

El artículo trata de la historia de una editorial argentina, la Editorial Abril creada en 1941 por Cesare Civita, un inmigrante judío que abandonó Italia después de la aprobación de las «leyes raciales». Abril publicaba historietas (El Pato Donald), fotonovelas (Idilio), revistas Femeninas (Claudia) y de actualidad (Panorama). Abril era una empresa familiar que supo utilizar una vasta red de relaciones en la Argentina, Italia y los Estados Unidos. La historia de la Editorial termina con un nuevo exilio de Cesare Civita en 1976. Se utilizan: fuentes de archivo, testimonios, revistas y libros.
La migración colombiana en España: ¿salvados o entrampados?
Authors: Actis Walter
Published: May 2009

El artículo presenta la evolución y características actuales de la emigración colombiana radicada en España, utilizando la información de fuentes oficiales, en especial una explotación —con datos inéditos— de la Encuesta Nacional de Inmigrantes de 2007. Entre otras cuestiones analiza la importancia de los vínculos transnacionales en el inicio del tránsito migratorio y en la situación actual, y revisa la inserción laboral en origen y destino, estudiando los procesos de movilidad ocupacional.
Cruzando fronteras. La reformulación de la latinidad al norte del Río Grande
Authors: Criado María Jesús
Published: May 2009

En este texto se describe la evolución y características de la población de origen hispano residente en los Estados Unidos. A partir de datos oficiales y otras fuentes secundarias se detalla y analiza su desarrollo en las últimas décadas y las principales tendencias observadas. Ello nos permitirá esbozar el perfil prevalente de este variado conjunto, su posición social y los procesos en los que están inmersos. Las dinámicas generadas afectan a ambos polos (inmigrados y sus descendientes y el orbe estadounidense) y apuntan a una reformulación de la latinidad en dicho contexto.
Complete larval development of the crab Ilia nucleus (Linnaeus, 1758) (Decapoda: Brachyura: Leucosiidae) reared under laboratory conditions
Authors: Bartilotti Cátia , González-Gordillo Juan Ignacio , Dos Santos Antonina
Published: May 2009

The complete larval development of the crab Ilia nucleus (Linnaeus, 1758) reared under laboratory conditions was obtained. The four zoeal stages and the megalopa are described and illustrated in detail. The larval features observed in I. nucleus fit into the characteristics of the family proposed by Rice (1980) for the zoeal stages and by Quintana (1986) for the megalopa. The morphological characters of larval stages of I. nucleus are compared with previous descriptions, and with those of other known larvae of Leucosiidae (only for subfamilies Ebaliinae and Leucosiinae). The present work supports the hypothesis that the subfamily Ebaliinae is a heterogeneous group. For the correct identification of a zoeal stage of a leucosiid crab, besides counting the number of setae on maxilliped exopods, the antennule as well as the pereiopods development should be used as additional characters.
Profile of acute poisoning in three health districts of Botswana
Authors: Kasule Mary , Malangu Ntambwe
Published: May 2009

Background: This study sought to characterise acute poisoning cases seen in three health districts of Botswana.Method: A retrospective review of patients’ records was conducted and included patients treated from January 2004 to December 2005. Data on the demographic status of the patients, information about the poisonous agent(s) involved, and the circumstances and outcomes of the poisoning incidents were recorded on a pre-tested data collection form.Results: A total of 590 cases of acute poisoning were included in the analysis. The most affected age category was that of children aged less than six years, who constituted 33.4% of the cases. Most incidents were recorded in the urban district of Gaborone. Seventy-eight percent (78%) of the incidents were accidental, with the remainder being intentional. The poisonous agents involved were pharmaceuticals (26.6%), natural toxins (25.6%), household products (14.6%), foods (14.4%), alcohol (6.9%), traditional medicines (4.7%), unspecified agents (3.2%), and agrochemicals (2.7%). The most common route of poison exposure was by oral (82.2%), followed by dermal contact (16.5%), while the inhalation of gases occurred in 1.2% of cases. An incidence rate of 4.7/1000, a case fatality rate of 3.8/100, and 1.5% of deaths were recorded over the two-year period.Conclusion: In conclusion, it can be stated that acute poisoning involved mainly young children and resulted in an incidence rate of 4.7/1000, a case fatality rate of 3.8/100, and 1.5% of deaths over the two-year period. There were differences based on age category, gender and residence of the victims, the types of toxic agents involved, as well as the circumstances and the outcomes of the poisoning incidents. Given the fact that pharmaceuticals, natural toxins, household products and foods were the agents most commonly involved, targeted interventions should take these differences into account in addressing the problem of acute poisoning.
The relationship between emotional intelligence and stress management
Authors: Ramesar Saras , Koortzen Pieter , Oosthuizen Rudolf M.
Published: May 2009

Regardless of where one lives in the world, one cannot escape three defi ning forces of our time: globalisation, the information revolution and the speed of change (Cascio, 2001). To ensure continued organisational performance and to maintain the competitive advantage, organisations must therefore constantly implement changes in strategy, structure, process and culture (Higgs, 2002; Langley, 2000). Goleman (1998) proposes a solution of self-awareness as a key skill in handling stress, thereby indicating that a lack of emotional intelligence in such an unstable environment means possible failure that can impact on everyone’s future. The general aim of this research was to determine whether there is a relationship between emotional intelligence and stress management in a group of managers. This was done through a quantitative study of the relationship between stress management and emotional intelligence. These constructs were operationalised by means of a combination of scales present in the Feelings and Emotions domain of the Occupational Personality Questionnaire (OPQ32i) and the Emotional Quotient Inventory (Bar-On EQ-i). The correlation and regression results seem to indicate that stress management (the ability to cope with stress) is a component of emotional intelligence, while stress can be either an input or an outflow of emotional intelligence or the lack thereof.
The Energy of Charge‐Transfer States in Electron Donor–Acceptor Blends: Insight into the Energy Losses in Organic Solar Cells
Authors: Veldman Dirk , Meskers Stefan C. J. , Janssen René A. J.
Published: May 2009

Here, a general experimental method to determine the energy ECT of intermolecular charge‐transfer (CT) states in electron donor–acceptor (D–A) blends from ground state absorption and electrochemical measurements is proposed. This CT energy is calibrated against the photon energy of maximum CT luminescence from selected D–A blends to correct for a constant Coulombic term. It is shown that ECT correlates linearly with the open‐circuit voltage (Voc) of photovoltaic devices in D–A blends via eVoc = ECT − 0.5 eV. Using the CT energy, it is found that photoinduced electron transfer (PET) from the lowest singlet excited state (S1 with energy Eg) in the blend to the CT state (S1 → CT) occurs when Eg − ECT > 0.1 eV. Additionally, it is shown that subsequent charge recombination from the CT state to the lowest triplet excited state (ET) of D or A (CT → T1) can occur when ECT − ET > 0.1 eV. From these relations, it is concluded that in D–A blends optimized for photovoltaic action: i) the maximum attainable Voc is ultimately set by the optical band gap (eVoc = Eg − 0.6 eV) and ii) the singlet–triplet energy gap should be ΔEST < 0.2 eV to prevent recombination to the triplet state. These favorable conditions have not yet been met in conjugated materials and set the stage for further developments in this area.
Linear clinical progression, independent of age of onset, in Niemann–Pick disease, type C
Authors: Yanjanin Nicole M. , Vélez Jorge I. , Gropman Andrea , King Kelly , Bianconi Simona E. , Conley Sandra K. , Brewer Carmen C. , Solomon Beth , Pavan William J. , Arcos‐Burgos Mauricio , Patterson Marc C. , Porter Forbes D.
Published: May 2009

Niemann–Pick disease, type C is a neurodegenerative, lysosomal storage disorder with a broad clinical spectrum and a variable age of onset. The absence of a universally accepted clinical outcome measure is an impediment to the design of a therapeutic trial for NPC. Thus, we developed a clinical severity scale to characterize and quantify disease progression. Clinical signs and symptoms in nine major (ambulation, cognition, eye movement, fine motor, hearing, memory, seizures, speech, and swallowing) and eight minor (auditory brainstem response, behavior, gelastic cataplexy, hyperreflexia, incontinence, narcolepsy, psychiatric, and respiratory problems) domains were scored. Data were collected from 18 current NPC patients and were extracted from records of 19 patients. Both patient cohorts showed a linear increase in severity scores over time. Cross‐sectional evaluation of current patients showed a linear increase in the severity score. Longitudinal chart review of historical data demonstrated that although age of onset varied significantly, the rate of progression appeared linear, independent of age of onset, and similar in all patients. Combining the data from both cohorts, disease progression could be modeled by the following equation: Ŝt0+x = Ŝt0 + 1.87x; where Ŝt0 is the initial score and Ŝt0+x is the predicted future score after x years. Our observation that disease progression is similar across patients and independent of age of onset is consistent with a biphasic pathological model for NPC. This scale may prove useful in the characterization of potential biomarkers, and as an outcome measure to monitor disease progression in NPC patients. © 2009 Wiley‐Liss, Inc.
Bindungsmechanismen in supramolekularen Komplexen
Authors: Schneider Hans‐Jörg
Published: May 2009

Kräfte‐Sammelsurium: Supramolekulare Komplexe, wie der gezeigte, beruhen meist auf einer Kombination unterschiedlichster Wechselwirkungen, wie Ionenpaarbildung, Wasserstoffbrücken und Stapelwechselwirkungen. Die nicht immer einfache Charakterisierung von Natur und Stärke der intermolekularen Kräfte liefert Beiträge zum Verständnis biomimetischer Systeme wie auch zum Design von synthetischen Rezeptoren, Wirkstoffen und intelligenten Materialien.

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Die supramolekulare Chemie hat in den letzten Jahren eine enorme Ausdehnung erfahren, sowohl mit Blick auf mögliche Anwendungen wie auch auf analoge biologische Systeme. Bildung und Funktion supramolekularer Komplexe werden durch eine Vielzahl von oft schwer zu differenzierenden nichtkovalenten Kräften bestimmt. Ziel dieses Aufsatzes ist es, die entscheidenden Wechselwirkungsmechanismen zusammenhängend darzustellen und das Gesamtgebiet auf diese Weise zu klassifizieren. Als Beispiele werden meist organische Wirt‐Gast‐Komplexe gewählt, unter Berücksichtigung auch von biologisch relevanten Fragestellungen. Das Verständnis und die Quantifizierung der intermolekularen Wechselwirkungen ist für die rationale Planung neuer supramolekularer Systeme, einschließlich intelligenter Materialien, ebenso von Bedeutung wie für die Entwicklung neuer Wirkstoffe.
Enantioselective Synthesis of β‐Iodo Morita–Baylis–Hillman Esters by a Catalytic Asymmetric Three‐Component Coupling Reaction
Authors: Senapati Bidyut Kumar , Hwang Geum‐Sook , Lee Sungil , Ryu Do Hyun
Published: May 2009

Die katalytische asymmetrische Kupplung von α,β‐acetylenischen Estern mit Aldehyden und Trimethylsilyliodid führt zu chiralen Morita‐Baylis‐Hillman‐Estern (siehe Schema, TMS=Trimethylsilyl). Die Reaktion verläuft äußerst enantioselektiv, und die Produkte lassen sich unter Erhaltung der Konfiguration in einem einzigen Schritt in β‐verzweigte Derivate umwandeln.

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Modified Nucleosides in Biochemistry, Biotechnology and Medicine.Herausgegeben von Piet Herdewijn.
Authors: Lakshman Mahesh K.
Published: May 2009

Wiley‐VCH, Weinheim 2008. 658 S., geb., 199.00 €.—ISBN 978‐35273118209

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Stereoselektive Pd‐katalysierte Carboaminoxylierung von Indolen mit Arylboronsäuren und TEMPO
Authors: Kirchberg Sylvia , Fröhlich Roland , Studer Armido
Published: May 2009

Wer A sagt, muss auch B sagen! Indole reagieren mit Arylboronsäuren in chemodivergenter Weise: Freies Indol und N‐Methylindol führen durch direkte C‐H‐Arylierung hauptsächlich zu den C(2)‐arylierten Indolen A, während N‐acylierte, N‐benzoylierte und N‐Boc‐geschützte Indole das arylcarboaminoxylierte Produkt B hoch diastereoselektiv in guten Ausbeuten ergeben.

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Coherent Multidimensional Vibrational Spectroscopy of Biomolecules: Concepts, Simulations, and Challenges
Authors: Zhuang Wei , Hayashi Tomoyuki , Mukamel Shaul
Published: May 2009

Good vibrations: The vibrational response of complex molecules to sequences of infrared pulses provides novel femtosecond snapshots of their structure and dynamics. This technique, which is the optical analogue of multidimensional NMR spectroscopy, gives correlation plots of motions during controlled time intervals between pulses that are applied to study protein folding, chirality, hydrogen‐bonding, phospholipid membranes, and chemical exchange.

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The response of complex molecules to sequences of femtosecond infrared pulses provides a unique window into their structure, dynamics, and fluctuating environments. Herein we survey the basic principles of modern two‐dimensional infrared (2DIR) spectroscopy, which analogous to those of multidimensional NMR spectroscopy. The perturbative approach for computing the nonlinear optical response of coupled localized chromophores is introduced and applied to the amide backbone transitions of proteins, liquid water, membrane lipids, and amyloid fibrils. The signals are analyzed using classical molecular dynamics simulations combined with an effective fluctuating Hamiltonian for coupled localized anharmonic vibrations whose dependence on the local electrostatic environment is parameterized by an ab initio map. Several simulation methods, (cumulant expansion of Gaussian fluctuation, quasiparticle scattering, the stochastic Liouville equations, direct numerical propagation) are surveyed. Chirality‐induced techniques which dramatically enhance the resolution are demonstrated. Signatures of conformational and hydrogen‐bonding fluctuations, protein folding, and chemical‐exchange processes are discussed.
Binding Mechanisms in Supramolecular Complexes
Authors: Schneider Hans‐Jörg
Published: May 2009

Forces to reckon with: Supramolecular complexes, such as the one shown, are normally based on a combination of different interactions such as ion pairing, hydrogen bonds, and stacking interactions. The not always simple characterization of the nature and strength of intermolecular forces provides assistance to the understanding of biomimetic systems, as well as for the design of synthetic receptors, drugs, and intelligent materials.

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Supramolecular chemistry has expanded dramatically in recent years both in terms of potential applications and in its relevance to analogous biological systems. The formation and function of supramolecular complexes occur through a multiplicity of often difficult to differentiate noncovalent forces. The aim of this Review is to describe the crucial interaction mechanisms in context, and thus classify the entire subject. In most cases, organic host–guest complexes have been selected as examples, but biologically relevant problems are also considered. An understanding and quantification of intermolecular interactions is of importance both for the rational planning of new supramolecular systems, including intelligent materials, as well as for developing new biologically active agents.
Sequencing Single DNA Molecules in Real Time
Authors: Ibach Jenny , Brakmann Susanne
Published: May 2009

One's enough: The direct observation of a DNA‐polymerase‐based “sequencing engine” using single‐molecule detection recently allowed single‐molecule sequencing by synthesis in real time. Nucleotides with a fluorescent marker at the 5′‐phosphate unit and zero‐mode waveguides are crucial components of this approach, which at last promises low‐cost genome‐scale sequencing.

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Modified Nucleosides in Biochemistry, Biotechnology and Medicine.Edited by Piet Herdewijn.
Authors: Lakshman Mahesh K.
Published: May 2009

Wiley‐VCH, Weinheim 2008. 658 pp., hardcover € 199.00.—ISBN 978‐3527318209

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Stereoselective Palladium‐Catalyzed Carboaminoxylations of Indoles with Arylboronic Acids and TEMPO
Authors: Kirchberg Sylvia , Fröhlich Roland , Studer Armido
Published: May 2009

Indoles are not indolent: Various indoles react with arylboronic acids chemodivergently. CH arylation of free indole and N‐methylindole gives the corresponding C(2)‐arylated indoles A whereas N‐acylated, N‐benzoylated, and N‐Boc‐protected indoles provide the corresponding arylcarboaminoxylated products B with excellent diastereoselectivity in good to excellent yields.

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Simulation of dry‐spinning process of polyimide fibers
Authors: Deng Gang , Xia Qingming , Xu Yuan , Zhang Qinghua
Published: May 2009

As one type of high‐performance fibers, the polyimide fibers can be prepared from the precursor polyamic acid via dry‐spinning technology. Unlike the dry‐spinning process of cellulose acetate fiber or polyurethane fiber, thermal cyclization reaction of the precursor in spinline with high temperature results in the relative complex in the dry‐spinning process. However, the spinning process is considered as a steady state due to a slight degree of the imidization reaction from polyamic acid to polyimide, and therefore a one‐dimensional model based on White‐Metzer viscoelastic constitutive equation is adopted to simulate the formation of the fibers. The changes of solvent mass fraction, temperature, axial velocity, tensile stress, imidization degree, and glass transition temperature of the filament along the spinline were predicted. The effects of spinning parameters on glass transition temperature and imidization degree were thus discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
An effective method to identify the type and content of α‐olefin in polyolefine copolymer by Fourier Transform Infrared–Differential Scanning Calorimetry
Authors: Zhang Qing , Chen Ping , Xie Xiaoli , Cao Xianwu
Published: May 2009

A new method for identification of ethylene/α‐olefin copolymer was established by Fourier Transform Infared (FTIR)–Differential Scanning Calorimetery (DSC) in this article. DSC and FTIR spectroscopy techniques were used to analysis the type and content of α‐olefin in polyolefine copolymer. FTIR was available to identify the structures of polyethylene and copolymers of ethylene with different α‐olefins. The type of polyethylene can be determined by the peak position of 1378 and 1369 cm−1. According to the peak location of 770, 784, and 895 cm−1, the type of α‐olefin can also be determined. DSC method was used to decide the position of melting peaks. The quantitative investigation of the content of α‐olefin in polyethylene was calculated by the formula: −ln(CH2 mol fraction) = −0.331+135.5/Tm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Crosslinking and stabilization of nanoparticle filled poly(1‐trimethylsilyl‐1‐propyne) nanocomposite membranes for gas separations
Authors: Shao Lei , Samseth Jon , Hägg May‐Britt
Published: May 2009

Poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) has been crosslinked using 4,4′‐diazidobenzophenone bisazide to improve its chemical and physical stability over time. Crosslinking PTMSP renders it insoluble in good solvents for the uncrosslinked polymer. Gas permeability and fractional free volume decreased as crosslinker content increased, while gas sorption was unaffected by crosslinking. Therefore, the reduction in permeability upon crosslinking PTMSP was due to decrease in diffusion coefficient. Compared with the pure PTMSP membrane, the permeability of the crosslinked membrane is initially reduced for all gases tested due to the crosslinking. By adding nanoparticles (fumed silica, titanium dioxide), the permeability is again increased; permeability reductions due to crosslinking could be offset by adding nanoparticles to the membranes. Increased selectivity is documented for the gas pairs O2/N2, H2/N2, CO2/N2, CO2/CH and H2/CH4 using crosslinking and addition of nanoparticles. Crosslinking is successful in maintaining the permeability and selectivity of PTMSP membranes and PTMSP/filler nanocomposites over time. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Flexural behavior of asymmetric structural foams
Authors: Barzegari M. Reza , Rodrigue Denis
Published: May 2009

Asymmetric structural foams were prepared by compression molding to study the flexural properties of these sandwich structures with different layer thickness. It was found that the flexural properties of asymmetric structural foams are function of load direction. Since the bending behavior is a combination of tension and compression, the stress distribution across the foam core plays a key role in describing their bending properties. The experimental results show that the compression modulus of integral foams is lower than its tensile modulus. Based on this information, a model is proposed to predict the flexural properties of asymmetric structural foams based on stress distribution. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and Studies of New 2‐(Coumarin‐4‐yloxy)‐4,6‐(substituted)‐s‐Triazine Derivatives as Potential Anti‐HIV Agents
Authors: Mahajan Dharmesh H. , Pannecouque Christophe , De Clercq Erik , Chikhalia Kishor H.
Published: May 2009

Novel 2‐(coumarin‐4‐yloxy)‐4,6‐(substituted)‐s‐triazine derivatives i. e., diaryltriazine (DATA) are reported as novel non‐nucleoside reverse transcriptase inhibitors (NNRTIs), were synthesized and their activities against human immunodeficiency virus HIV‐1 (III‐B), HIV‐2 (ROD), and the double RT mutant HIV‐1 (K103N and Y181C) were assessed. Modifications at positions 4 and 6 of the coumarinyl‐triazine scaffold generated interesting derivatives displaying good to moderate anti‐HIV activity against selected HIV strains as compared to nevirapine and efavirenz. The synthesized compounds were characterized by FTIR, 1H‐NMR, and mass spectral data together with elemental analysis.
Novel 3,6‐Disubstituted 7H‐1,2,4‐Triazolo[3,4‐b][1,3,4]thiadiazines: Synthesis, Characterization, and Evaluation of Analgesic / Anti‐inflammatory, Antioxidant Activities
Authors: Tozkoparan Birsen , Aytaç Sevim Peri , Aktay Göknur
Published: May 2009

In this study, the synthesis of a new series of 3,6‐disubstituted‐7H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazine 1a–4c compounds derived from 4‐amino‐3‐substituted‐1,2,4‐triazole‐5‐thiones 1–4 is described. All of the synthesized compounds were screened for their possible analgesic / anti‐inflammatory, antioxidant activities and gastric toxicity. The compound 2c was found to have both significant analgesic and consistent anti‐inflammatory activity without inducing any gastric lesions along with minimal lipid peroxidation. A deep insight into the structures of the active compounds revealed that the compounds carrying an electron withdrawing group (a chloride or fluoride) on the phenyl ring at 6‐position of the condensed heterocyclic derivatives exhibited noticeable higher activity.
Synthesis and Biological Evaluation of Some Novel Polysubstituted Pyrimidine Derivatives as Potential Antimicrobial and Anticancer Agents
Authors: Rostom Sherif A. F. , Ashour Hayam M. A. , Abd El Razik Heba A.
Published: May 2009

Synthesis and evaluation of the antimicrobial and cytotoxic activity of two series of polysubstituted pyrimidines comprising the thioether functionality and other pharmacophores, reported to contribute to various chemotherapeutic activities are described. All newly synthesized compounds were subjected to in‐vitro antibacterial and antifungal screening. Out of the compounds tested, 18 derivatives displayed an obvious inhibitory effect on the growth of the tested Gram‐positive and Gram‐negative bacterial strains, with special effectiveness against the Gram‐positive strains. Compounds 1, 2, 6, 7, 9, 10, 11, 21, and 24 revealed remarkable broad antibacterial spectrum profiles. Among those, compounds 1, 2, 6, 7, 9, and 24 exhibited an appreciable antifungal activity against C. albicans. Compound 2 proved to be the most active antimicrobial member identified here as it showed twice the activity of ampicillin against B. subtilis and the same activity of ampicillin against M. Luteus and P. aeruginosa together with a moderate antifungal activity. Further, eleven analogs were evaluated for their in‐vitro cytotoxic potential utilizing the standard MTT assay against a panel of three human cell lines: breast adenocarcinoma MCF7, hepatocellular carcinoma HePG2, and colon carcinoma HT29. The obtained data revealed that six of the tested compounds 1, 3, 7, 12, 13, and 15 showed a variable degree of cytotoxic activity against the tested cell lines at both the LC50 and LC90 levels. Compound 7 proved to be the most active cytotoxic member in this study with special effectiveness against the colon carcinoma HT29 and breast cancer MCF7 human cell lines for LC50 and LC90. Thus, compounds 1 and 7 could be considered as possible dual antimicrobial‐anticancer agents.
Execution models for reconfigurable embedded real‐time systems
Authors: Khalgui Mohamed , Hanisch Hans‐Michael
Published: May 2009

This paper deals with the verification and assignment into the execution environment of Reconfigurable Control Applications following the Component‐based International Industrial Standard IEC61499. According to this Standard, a Function Block (FB) is an event‐triggered component and an application is an FB network that has to meet temporal properties according to user requirements. If a reconfiguration scenario is applied at run‐time, then the FB network implementing the application is totally changed or modified. To cover all possible cases, we classify such scenarios into three classes and we define an agent‐based architecture designed with nested state machines to automatically handle all possible reconfigurations. To verify and assign Function Blocks corresponding to each reconfiguration scenario into the execution environment, we define an approach based on the exploration of reachability graphs to verify temporal properties. This approach constructs feasible Operating System tasks encoding the FB network that corresponds to each scenario. Therefore, the application is considered as sets of Operating System (OS) tasks where each set is to load in memory when the corresponding reconfiguration scenario is applied by the agent. We developed the toolX‐Assignsupporting these contributions that we apply on the FESTO production system available in our research laboratory. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Improved exponential estimates for neutral systems
Authors: Shu Zhan , Lam James , Xu Shengyuan
Published: May 2009

Improved exponential estimates and a new sufficient condition for the exponential stability of neutral type time‐delay systems are established in terms of linear matrix inequalities (LMIs). A new Lyapunov‐Krasovskii functional candidate with appropriately constructed exponential terms is introduced to prove the exponential stability and to reduce the conservatism. For the uncertain case, a corresponding condition for the robust exponential stability is also given. It is shown by numerical examples that the proposed conditions are less conservative than existing results. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
A novel approach for root distribution analysis of linear time‐invariant systems using Routh and Fuller tables
Authors: Sivanandam S. N. , Deepa S. N.
Published: May 2009

The root distribution of a given characteristic equation of a linear time‐invariant system can be analyzed with the help of a Routh table using the elements of the first column in the table. In the case of unstable systems, sometimes, a zero element may appear in the third row of the first column of the Routh array. This prematurity can be suitably handled as indicated by various authors. In this paper, the given characteristic polynomial having roots in the right hand plane is multiplied by a suitable polynomial, and Routh and Fuller tables are applied for the resultant polynomial to infer the complete root distribution. Further, the column polynomials from each table are adopted to know more about root distribution, which forms the core of the proposed work. The Routh table helps in counting and locating roots in the s‐plane, and the Fuller table helps in depicting whether the roots are distinct or complex in nature. In this regard, it is shown in this paper that the simultaneous integration of Routh and Fuller tables yields a good amount of information regarding the root distribution in the s‐plane. The newly presented procedure is illustrated with examples. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Tracking control of a piezo‐actuated stage based on a frictional model
Authors: Huang Yi‐Cheng , Lin Mou‐Sheng
Published: May 2009

The tracking control accuracy of a piezoelectric actuator (PEA) is limited due to the actuator's inherent hysteretic nonlinearity. Direct drive of PEA on a positioning stage with friction force will cause control problems. An approximated dynamic model of PEA with consideration of friction force is novel synthesized for control. This model is based on a second‐order transfer function with two parameterization terms. The first time delay term consists of the hysteresis of piezo effect combined with frictional force lag with varying velocity. The second term is comprised of both presliding and sliding regimes. The H‐infinite tracking controller is designed to compensate for the structural uncertainty associated with time delay and the unstructured frictional force in the PEA stage. Iterative Learning Control is implemented to reduce the unmodeled repetitive error by a factor of 20. Numerical simulations and experimental tests consolidate the root mean square (RMS), positioning error close to the hardware reproducibility and accuracy level. Experimental results show the controlled stage can be potentially used for precise positioning. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
ESA in high‐order linear systems via output feedback
Authors: Yu Hai‐Hua , Duan Guang‐Ren
Published: May 2009

This paper considers eigenstructure assignment in high‐order linear systems via output feedback. Parametric expressions for the left and right closed‐loop eigenvectors associated with the finite closed‐loop eigenvalues and two simple and complete parametric solutions for the feedback gain matrices are obtained on the basis of the parametric solutions of the generalized high‐order Sylvester matrix equations. This approach does not impose any restrictions on the closed‐loop eigenvalues. An illustrative example shows the effect of the proposed approach. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Finite‐time tracking control of a nonholonomic mobile robot
Authors: Wang Zhao , Li Shihua , Fei Shumin
Published: May 2009

In this paper, the finite‐time tracking problem is investigated for a nonholonomic wheeled mobile robot in a fifth‐order dynamic model. We consider the whole tracking error system as a cascaded system. Two continuous global finite‐time stabilizing controllers are designed for a second‐order subsystem and a third‐order subsystem respectively. Then finite‐time stability results for cascaded systems are employed to prove that the closed‐loop system satisfies the finite‐time stability. Thus the closed‐loop system can track the reference trajectory in finite‐time when the desired velocities satisfy some conditions. In particular, we discuss the control gains selection for the third‐order finite‐time controller and give sufficient conditions by using Lyapunov and backstepping techniques. Simulation results demonstrate the effectiveness of our method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Impulsive‐mode controllablizability revisited for descriptor linear systems
Authors: Wu Ai‐Guo , Duan Guang‐Ren , Yu Hai‐Hua
Published: May 2009

New criteria for impulsive‐mode controllablizability of descriptor linear systems are proposed by adopting the null space approach. The range of the possible dynamical orders of the closed‐loop system with impulsive‐mode controllability is characterized in terms of the original system matrices. Moreover, the parametric expressions of the impulsive‐mode controllablizing controllers are also established. Since only the orthogonal transformations are involved, the design approach is numerically stable. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Amino acids as regulators of gene expression in mammals: Molecular mechanisms
Authors: Bruhat Alain , Chérasse Yoan , Chaveroux Cédric , Maurin Anne‐Catherine , Jousse Céline , Fafournoux Pierre
Published: May 2009

In mammals, the impact of nutrients on gene expression has become an important area of research. Because amino acids have multiple and important functions, their homeostasis has to be finely maintained. However, amino acidemia can be affected in some nutritional conditions and by various forms of stress. Consequently, mammals have to adjust physiological functions involved in the adaptation to amino acid availability. Part of this regulation involves the modulation of numerous gene expression. It has been shown that amino acids by themselves can modify the expression of target genes. This review focuses on the recent advances in the understanding of the mechanisms involved in the control of mammalian gene expression in response to amino acid limitation. © 2009 International Union of Biochemistry and Molecular Biology, Inc.
The endoplasmic reticulum stress signaling pathways in plants
Authors: Urade Reiko
Published: May 2009

The unfolded protein response (UPR) is an evolutionarily conserved mechanism by which all eukaryotic cells preserve the homeostasis of the endoplasmic reticulum (ER) in the face of accumulation of unfolded proteins in the ER. Plants possess at least two signaling pathways specific for UPR. ER membrane‐bound ER stress sensor/transducers, AtbZIP60 and AtbZIP28, are basic leucine zipper transcription factors that are activated by regulated intramembrane proteolysis systems and regulate transcription of the UPR genes. These signaling pathways play important roles not only in the UPR but also in other biological processes such as the response to pathogens and heat stress. © 2009 International Union of Biochemistry and Molecular Biology, Inc.
Disulfide Bond Substitution by Directed Evolution in an Engineered Binding Protein
Authors: Drevelle Antoine , Urvoas Agathe , Hamida‐Rebaï Mériam Ben , Van Vooren Gérard , Nicaise Magali , Valerio‐Lepiniec Marie , Desmadril Michel , Robert Charles H. , Minard Philippe
Published: May 2009

Breaking ties: The antitumour protein, neocarzinostatin (NCS), is one of the few drug‐carrying proteins used in human therapeutics. However, the presence of disulfide bonds limits this protein's potential development for many applications. This study describes a generic directed‐evolution approach starting from NCS‐3.24 (shown in the figure complexed with two testosterone molecules) to engineer stable disulfide‐free NCS variants suitable for a variety of purposes, including intracellular applications.

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The chromoprotein neocarzinostatin (NCS) has been intensively studied for its antitumour properties. It has recently been redesigned as a potential drug‐carrying scaffold. A potential limit of this protein scaffold, especially for intracellular applications, is the presence of disulfide bonds. The objective of this work was to create a disulfide‐free NCS‐derived scaffold. A generic targeted approach was developed by using directed evolution methods. As a starting point we used a previously engineered NCS variant in which a hapten binding site had been created. A library was then generated in which cysteine Cys88 and Cys93 and neighbouring residues were randomly substituted. Variants that preserved the hapten binding function were selected by phage display and further screened by colony filtration methods. Several sequences with common features emerged from this process. The corresponding proteins were expressed, purified and their biophysical properties characterised. How these selected sequences rescued folding ability and stability of the disulfide‐free protein was carefully examined by using calorimetry and the results were interpreted with molecular simulation techniques.
Phenolic Oxime Oligomers Inhibit Alzheimer's Amyloid Fibril Formation and Disaggregate Fibrils In Vitro
Authors: Dolphin Gunnar T. , Renaudet Olivier , Ouberai Myriam , Dumy Pascal , Garcia Julian , Reymond Jean‐Louis
Published: May 2009

See you later amyloid β: A screen of a small library of oxime oligomers with an HTS fluorescence assay for amyloid fibril inhibition and subsequent investigation by atomic force microscopy revealed two new micromolar inhibitors of amyloid fibril formation. These new inhibitors have IC50 values in the 10 μM range.

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Polymer‐Säure‐Komposite auf Basis strahlungsinduzierter Pfropfpolymerisation für Hochtemperatur‐PEM‐Brennstoffzellen
Authors: Schmidt‐Naake G.
Published: May 2009

Komposite aus basischen Polymeren und Säuren sind geeignete Protonenleiter für Polymerelektrolytmembran‐Brennstoffzellen (PEM‐FC), die bei 120 °C und höheren Temperaturen ohne oder mit nur geringer Befeuchtung der Betriebsgase arbeiten. Durch strahlungsinduzierte Pfropfpolymerisation auf handelsüblichen ETFE‐Filmen (Poly(tetrafluorethylen‐alt‐ethylen) stellt man mit den Monomeren 1‐Vinylimidazol, 4‐Vinylpyridin, N‐Vinylformamid und Glycidylmethacrylat basische Pfropfpolymere her und dotiert diese mit Phosphorsäure. In vergleichenden Struktur‐Eigenschafts‐Untersuchungen werden diese sehr unterschiedlichen Polymer‐Säure‐Komposite hinsichtlich erreichbarer Pfropfgrade, Dotierlevel, basischer Funktionsdichten, thermischer Stabilitäten, spezifischer Protonenleitfähigkeiten und des Brennstoffzellentests bewertet.
Entwicklung eines mikrostrukturierten Methanolreformers gekoppelt mit einer Hochtemperatur‐PEM Brennstoffzelle
Authors: Kolb Dr‐Ing. G. , Schelhaas K.‐P. , Wichert M. , Burfeind J. , Heßke C. , Bandlamudi G.
Published: May 2009

Ziel der vorliegenden Arbeit war es, einen portablen Stromerzeuger mit einer elektrischen Nettoleistung von 100 W zu realisieren. Dazu wurde am Institut für Mikrotechnik Mainz (IMM) ein integrierter mikrostrukturierter Methanolreformer auf der Basis des oxidativen Wasserdampfreformierens entwickelt. Der Reformer wurde nach Einzeltests schließlich mit einer vom Zentrum für Brennstoffzellentechnik (ZBT) entwickelten Hochtemperatur‐PEM‐Brennstoffzelle gekoppelt.