bluuebunny/crossref_metadata_2025 huggingface dataset:
New Directions in Revenue Management Research
Authors: Dana James D.
Published: December 2008

Research in revenue management is rapidly changing as the environment in which firms operate changes. The Internet, the adoption of new information technologies, and other market forces are driving a new wave of research in revenue management. At the same time, more and more industries are adapting the tools of revenue management to their needs. Promising research directions are more sophisticated models of consumer behavior, more general models and understanding of rivalry, and more general pricing mechanisms. These are important issues for today's revenue managers and promising areas for both theoretical and empirical research.
Multiperiod Models with Capacities in Competitive Supply Chain
Authors: Perakis Georgia , Zaretsky Marina
Published: December 2008

This paper considers a supply chain setting where several capacitated suppliers compete for orders from a single retailer in a multiperiod environment. At each period, the retailer places orders to the suppliers in response to the prices they announce. Each supplier has a fixed capacity. We consider a make‐to‐stock setting where the retailer can carry inventory. The retailer faces exogenous, price‐dependent demand. We study the problem using ideas from fluid models. In particular, we (i) analyze when there are pure equilibrium policies in this setting and characterize the structure of these policies; (ii) consider coordination mechanisms; and (iii) present some preliminary computational results. We also consider a modified model that uses option contracts to coordinate the supply chain.
Order Progress Information: Improved Dynamic Emergency Ordering Policies
Authors: Gaukler Gary M. , Özer Özalp , Hausman Warren H.
Published: December 2008

Technologies such as radio‐frequency identification and global positioning systems can provide improved real‐time tracking information for products and replenishment orders along the supply chain. We call this type of visibility order progress information. In this paper, we investigate how order progress information can be used to improve inventory replenishment decisions. To this end, we examine a retailer facing a stochastic lead time for order fulfillment. We characterize a replenishment policy that is based on the classical ( Q, R) policy and that allows for releasing emergency orders in response to the order progress information. We show that the optimal structure of this policy is given by a sequence of threshold values dependent on order progress information. In a numerical study we evaluate the cost savings due to this improved replenishment policy.
EVALUATING THE ALTERNATIVE SOLUTIONS OF WALL INSULATION BY MULTICRITERIA METHODS/PASTATŲ SIENŲ ŠILTINIMO VARIANTŲ VERTINIMAS TAIKANT DAUGIAKRITERIUS METODUS
Authors: Ginevičius Romualdas , Podvezko Valentinas , Raslanas Saulius
Published: December 2008

The economic effect of buildings’ renovation largely depends on implementation of energy saving methods and devices. A very high economic effect is achieved by wall insulation. In this respect, it is even higher than the replacement of windows. The alternative solutions of wall insulation of buildings differ in the materials used, labour expenditure and other aspects. The cost of renovation depends on the solutions made. The criteria describing the available wall insulation alternatives may have different values. Moreover, they may change in different directions, i.e. a higher value of some criteria denotes a better state, while for others they mean a worse situation. In this environment, a compromise variant is required, which can be found by multicriteria evaluation methods. To reduce the effect of various methods on calculation results, it can be recommended to assess the object (or phenomenon) considered by several different methods, with a subsequent determination of the average estimate value. In this way, the disadvantages of some particular multicriteria evaluation methods could be compensated by the advantages of others. The integration of methods will be correct if there is a correlation between the values obtained by different methods. Santrauka Ekonominis pastatų renovacijos efektyvumas priklauso nuo energiją taupančių priemonių įgyvendinimo. Pastatų sienų šiltinimas yra viena iš geriausių priemonių ir net efektyvesnis energijos taupymo požiūriu negu langų keitimas. Pastatų sienų šiltinimo variantai skiriasi vienas nuo kito pagal medžiagas, darbo sąnaudas ir pan. Nuo to priklauso renovacijos kaina. Kriterijai, atspindintys skirtingus sienų šiltinimo variantus, gali turėti įvairių reikšmių. Gali skirtis jų kitimo kryptys, t. y. vienų kriterijų reikšmių didėjimas padėtį gerina, kitų – blogina. Kompromisiniam variantui pasirinkti padeda daugiakriterio vertinimo metodai (MCDA). Norint mažinti metodų specifikos įtaką skaičiavimų rezultatams, tą patį nagrinėjamą reiškinį tikslinga vertinti keliais būdais, paskui nustatyti šio vertinimo vidurkį. Tokiu atveju vienų daugiakriterio vertinimo būdų trūkumus kompensuoja kitų būdų privalumai. Metodų susiejimas bus korektiškas, jeigu reikšmės, gautos naudojant įvairius būdus, tarpusavyje koreliuoja.
The basic construction materials industry and today’s vast housing shortage
Authors: Salas J. , Oteiza I.
Published: December 2008

This paper documents some of the aspects of the major challenge facing world-wide building: humanity's daunting shortage of basic housing, monographically focusing on what this means for the basic building materials industry. These needs have created the greatest demand ever for ex-novo solutions and an exponential increase in slum rehabilitation and improvement, translated here into the need for construction materials and more specifically, cement, as the emblematic component of buildings.
MAGNETIC RESONANCE SIGNAL LOSS IN TURBULENT SHEAR FLOW
Authors: JOU LIANG-DER
Published: December 2008

NMR signal loss due to turbulent shear flow is discussed, and a general expression for the phase fluctuation is derived. In the presence of flow shear, the velocity fluctuation perpendicular to the direction of magnetic gradient and the Reynolds stress can cause loss of MR signal Most of signal loss results from the boundary layer, where the flow shear is strong in turbulent pipe flaw, Half the signal loss within the mixing layer distal to a moderate stenosis is caused by the velocity fluctuation in the direction of magnetic gradient, while the remaining results from the velocity, fluctuation perpendicular to the magnetic gradient. The use of eddy diffusivity for the description of signal dephasing in a spin echo sequence is also addressed; A positive, constant eddy diffusivity can not describe the temporal change of phase fluctuation correctly.
ADAPTIVE BEAMFORMER WITH COMBINATION OF SUBBAND FILTERING FOR HEARING-AID SYSTEMS BACKGROUND NOISE REDUCTION
Authors: TAI CHENG-CHI , CHANG CHIH-HSING , TAN CHUAN-CHING , HUANG TSUNG-WEN , SU CHING-CHAU
Published: December 2008

In this paper, we present a noise reduction technique for hearing-aid systems. The proposed algorithm adopted adaptive beamformer with combination of subband filtering technique. The structure of conventional hearing aids is relatively simple. They amplify ambient sounds that include speech signal as well as noise. Because noise and human speech signal are amplified at the same time, hearing-aid users can't clearly hear speech signal in noisy environment. The direction of sound can be used to discriminate speech signal from noise by combining adaptive noise canceller and adaptive beamformer. We have developed a system that based on the constrained adaptive noise canceller to preserve speech signal from straight ahead and minimize background noise arriving from other directions. This system also uses subband filtering technique to reduce the requirement for computation and enhance the flexibility of the system. The performance of this system is illustrated using simulated and real-world noises. The results show that the developed system can reserve the right ahead speech signal and substantially reject noises from other directions.
THREE-DIMENSIONAL ANALYSIS OF KINEMATIC AND KINETIC COORDINATION OF THE LOWER LIMB JOINTS DURING STAIR ASCENT AND DESCENT
Authors: LIN HSIU-CHEN , LU TUNG-WU , HSU HORNG-CHAUNG
Published: December 2008

Being a common daily activity, stair locomotion places much higher loads on the lower limb than level walking does so a better understanding of the biomechanics of this activity is important for evaluation and treatment for patients with lower limb problems. The purpose of the present study was to investigate the three-dimensional dynamics and coordination of the joints of the lower limb during the stance phase of stair ascent and descent. Ten normal young adult subjects were recruited to ascend and descend stairs in a gait laboratory where the three-dimensional kinematic and kinetic data as well as muscle electromyography (EMG) were collected. The sagittal ranges of motion during stance phase of stair ascent were from 1.85° extension to 53.5° flexion for the hip, 13.1° to 60.1° flexion for the knee and 13.8° dorsiflexion to 14.0° plantarflexion for the ankle. Corresponding data for stair descent were 4.78( to 13.16( flexion for the hip, 8.3° to 77.6° flexion for the knee and 18.3° dorsiflexion to 27.4° plantarflexion for the ankle. Maximum extensor moments of 8.5% and 15.6% (Nm/BW/LL) were required at the hip and knee respectively during loading response while 19.4% (Nm/BW/LL) at the ankle shortly before toe-off. During stair descent, maximum extensor moments of about 4.4% were required at the hip during loading response and before toe-off while 13.3% and 15.2% (Nm/BW/LL) at the knee and ankle respectively before toe-off The joint angles, moments, and powers in the frontal and transverse planes were relatively small, except for hip abduction. The hip abductor moments and powers were significantly bigger than those of the knee and ankle in both stair activities. Joint powers and the corresponding muscle activation patterns in stair ascent were significantly different from those in descent, with concentric powers generated mostly during stair ascent and with eccentric powers stair descent. The differences of the movements of the lower limb during stair ascent and descent were due to different safety requirements and kinematic and kinetic constraints from the stairs. The complete description of the biomechanics of the lower extremity while performing stair locomotion will be helpful for the planning and evaluation of treatment programs for patients with lower limb problems.
BLOOD-DERIVED, TISSUE ENGINEERING BIOMATERIALS
Authors: BURNOUF THIERRY
Published: December 2008

Fibrin sealant and platelet gels are human blood-derived, biodegradable, non toxic, surgical products obtained by mixing a fibrinogen concentrate or a platelet rich plasma with thrombin, respectively. Fibrin sealant is now a well known surgical tool increasingly used to stop or control bleeding, or to provide air and fluid tightness in many surgical situations. Platelet gels are newly developed preparations that are of specific interest because they contain numerous physiological growth factors and cytikines that are released upon the activation of blood platelets by thrombin. These growth factors, including PDGF, TGF-β 1, BMP, and VEGF have been shown to stimulate cell growth and differentiation with special clinical benefits for soft and bony tissue healing and regeneration. Platelet gels allow surgeons to manipulate the cellular environment of surgical sites and to guide tissue regeneration. A specific interest of such products is observed for the induction of osteogenesis and chondrogenesis. Advances in the preparation, clinical use, and safety of these two important classes of blood-derived biomaterials are reviewed.
A COMPUTER-AIDED SYSTEM FOR MASS DETECTION AND CLASSIFICATION IN DIGITIZED MAMMOGRAMS
Authors: YANG SHENG-CHIH , WANG CHUIN-MU , CHUNG YI-NUNG , HSU GIU-CHENG , LEE SAN-KAN , CHUNG PAU-CHOO , CHANG CHEIN-I
Published: December 2008

This paper presents a computer-assisted diagnostic system for mass detection and classification, which performs mass detection on regions of interest followed by the benign-malignant classification on detected masses. In order for mass detection to be effective, a sequence of preprocessing steps are designed to enhance the intensity of a region of interest, remove the noise effects and locate suspicious masses using five texture features generated from the spatial gray level difference matrix (SGLDM) and fractal dimension. Finally, a probabilistic neural network (PNN) coupled with entropic thresholding techniques is developed for mass extraction. Since the shapes of masses are crucial in classification between benignancy and malignancy, four shape features are further generated and joined with the five features previously used in mass detection to be implemented in another PNN for mass classification. To evaluate our designed system a data set collected in the Taichung Veteran General Hospital, Taiwan, R.O.C. was used for performance evaluation. The results are encouraging and have shown promise of our system.
A COMPACT HALF-BRIDGE INDUCTION HEATING SYSTEM FOR MAGNETIC NANOPARTICLE THERMOTHERAPY APPLICATIONS
Authors: Tai Cheng-Chi , Chen Ming-Kun
Published: December 2008

Appling magnetic nanoparticle (MNP) in curing cancers has been a significant subject of medical research. A variety of switched-mode resonant inverters using voltage-fed-type high-frequency applicator with power MOSFET (metal oxide semiconductor field effect transistor) gate has been recently developed for medical use in electromagnetic thermotherapy. In this paper, a MNP heating system is presented and the electrical circuit characteristics of resonant components are analyzed. A half-bridge induction heating incorporate component functions directly at the applicator thereby reducing the size, weight, and cost of MNP heating systems. Preliminary heating results show a rise of about 3.8°C with 10-nm MNP for a 220-kHz frequency during the first 20 min.
DESIGN AND CONTROL OF A FLAPPER ACTUATED BRAILLE PRINTER BASED ON PC STANDARD INTERFACES
Authors: Tsay Huoy-Shyi , Yeh Fung-Huei
Published: December 2008

A cost-effective and portable Braille printer with low noise is designed in this study. To reach this goal, the compressive printing concept is used and the Braille typesetting, the signal transmission interface module, the signal control module, and the Braille printing cell are designed and integrated. To increase the portability, the Braille printer is designed to use A4 size paper and each page can print at most twenty-four rows and twenty-seven Braille characters in each row. The typesetting of the printing page is designed to contain twenty-seven side-by-side Braille printing cells and each printing cell contains two low cost flapper mechanisms for performing the low noise and cost-effective Braille print. The logic signal control module then controls a total of fifty-four flappers. The logic signals are transmitted through the integrated signal transmission interface module based on two common standard personal computer interfaces: Serial/RS232 and Universal Serial Bus 2.0. Subsequently, the pre-processing software is programmed based on the hardware developed. The integration of the software and hardware is successfully validated, and this newly designed Braille printer can be further used by the visually impaired for self-printing.
THE OPTIMAL MAGNETIC FORCE FOR A NOVEL ACTUATOR COUPLED TO THE TYMPANIC MEMBRANE: A FINITE ELEMENT ANALYSIS
Authors: Lee Chia-Fone , Chen Jyh-Horng , Chou Yuan-Fang , Liu Tien-Chen
Published: December 2008

A new type of electromagnetic vibration transducer designed to be placed onto the tympanic membrane will be developed. Such an electromagnetic transducer should have the following characteristics: small in size, high-energy efficiency and suitable frequency bandwidth. In order to find out the optimal electromagnetic force and to predict the frequency-amplitude characteristics, a finite element middle ear biomechanical model was used to derive the optimal magnetic force of the actuator in this study. First, the electromagnetic transducer coupled to the ear drum was created by using a computer-aided design (CAD). Then the new coupled tympanic membrane-transducer complex was loaded to a 3-dimensional biomechanical model in the middle. The air gap between magnet and coil, input current and vibration force were calculated by finite element analysis simulation. In addition, gain and frequency response curves of the actuator were also calculated. Predicted displacement of tip of the malleus induced by the sound pressure of 80 dB SPL with different input currents are computed from the finite element model over the auditory frequency range of 100–8000 Hz as the force input into the ANSYS software. Simulated results show displacements of vibration are about 100 nm in the range from 100–1000 Hz and reduced when the frequencies are higher than 1000 Hz. Functional gains were about 20–25 dB across the 100 to 8,000 Hz frequency range.
DESIGN AND IMPLEMENTATION OF ECG COMPRESSION ALGORITHM WITH CONTROLLABLE PERCENT ROOT-MEAN-SQUARE DIFFERENCE
Authors: Tseng Chwan-Lu , Hsiao Chun-Chieh , Chou I-Chi , Hsu Chia-Jung , Chang Yi-Ju , Lee Ren-Guey
Published: December 2008

In this paper, the orthogonality of coefficient matrices of wavelet filters is utilized to derive the energy equation for the relation between time-domain signal and its corresponding wavelet coefficients. Using the energy equation, the relationship between the wavelet coefficient error and the reconstruction error is obtained. The errors considered in this paper include the truncation error and quantization error. This not only helps to control the reconstruction quality but also brings two advantages: (1) It is not necessary to perform inverse transform to obtain the distortion caused by compression using wavelet transform and can thus reduce computation efforts. (2) By using the energy equation, we can search for a threshold value to attain a better compression ratio within the range of a pre-specified percent root-mean-square difference (PRD) value. A compression algorithm with run length encoding is proposed based on the energy equation. In the end, the Matlab software and MIT-BIH database are adopted to perform simulations for verifying the feasibility of our proposed method. The algorithm is also implemented on a DSP chip to examine the practicality and suitability. The required computation time of an ECG segment is less than 0.0786 ,s which is fast enough to process real-time signals. As a result, the proposed algorithm is applicable for implementation on mobile ECG recording devices.
EFFECT OF ELECTROSTATIC FIELD ON PROLIFERATION AND CYTOKINE SECRETION OF MACROPHAGE CELLS
Authors: Ho Yi-Ching , Hou Shao-Yi , Fang Tzan , Liu Hsuan-Liang , Fang Hsu-Wei
Published: December 2008

Electricity has been shown to exhibit significant effects on immunological responses in many studies. In this study, an electrostatic filed induced device was first applied to the macrophage cell culturing process. Mouse macrophage-like cells J774 A.1 were exposed to the electrostatic field of 1.5 kV for 1, 2, and 6 days, respectively. The results show that the electrostatic field can inhibit cell proliferation and TNF-α secretion in six days. Cell proliferation is decreased and TNF-α secretion is increased with increasing voltage applied from 0 kV to 0.8 kV and 1.2 kV of the electrostatic fields.
(N‐Salicylidene)aniline Derived Schiff Base Complexes of Methyltrioxorhenium(VII): Ligand Influence and Catalytic Performance
Authors: Zhou Ming‐Dong , Yu Yang , Capapé Alejandro , Jain Kavita R. , Herdtweck Eberhardt , Li Xiao‐Rong , Li Jun , Zang Shu‐Liang , Kühn Fritz E.
Published: December 2008

It′s a fine line: Methyltrioxorhenium(VII) (MTO) readily forms 1:1 adducts with several N‐(salicylidene)aniline derived Schiff bases. Steric and electronic effects of the ligands play a major role when it comes to stability and catalytic activity. Good donors on the Schiff base ligands, in general, lead to shorter ReO(Schiff base) bridges and lower catalytic activity, while it is the opposite for acceptor ligands on the Schiff bases.

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Methyltrioxorhenium(VII) (MTO) readily forms 1:1 adducts with several N‐(salicylidene)aniline derived Schiff bases. If the aromatic rings of the N‐(salicylidene)aniline ligands display non‐donating or electron withdrawing substituent groups, the resulting MTO adducts show good activities in olefin epoxidations. However, steric effects seem to play a major role, leading often to instable o‐ and m‐Schiff base–MTO adducts, while p‐substituted Schiff bases usually lead to more stable adducts. In catalysis, electron‐withdrawing substituents on the aniline moiety lead to better catalysts than electron donating ones. The gap between good catalysts and instable or non‐existing compounds, however, is small. The general tendency, however, that good donors on the Schiff base ligands lead to shorter ReO(Schiff base) bridges and lower catalytic activity, while the opposite is true with acceptor ligands on the Schiff bases, seems to be quite clear.
BRI2 as a central protein involved in neurodegeneration
Authors: Tsachaki Maria , Ghiso Jorge , Efthimiopoulos Spiros
Published: December 2008

BRI2 is a protein that when mutated causes familial British and familial Danish dementias. Upon cleavage, the mutated BRI2 proteins release the peptides ABri and ADan, which are amyloidogenic and accumulate in the brains of patients. Although BRI2 has an unknown function, several reports indicate that it could play multiple roles. For example, the fact that it exists at the cell surface as a homodimer indicates that it could be involved in cell signaling events by acting as a receptor. BRI2 also interacts with amyloid precursor protein (APP), involved in Alzheimer's disease (AD). In cell cultures and mouse models of AD, BRI2 inhibits APP processing and reduces amyloid β peptide deposition. The interaction between the two proteins could be responsible for the neuropathological similarities between familial British/Danish dementias and AD. The study of BRI2, which is central in familial British and Danish dementia, could unravel underlying molecular mechanisms of neurodegeneration.
The immunoglobulin superfamily of neuronal cell adhesion molecules: Lessons from animal models and correlation with human disease
Authors: Katidou Markella , Vidaki Marina , Strigini Maura , Karagogeos Domna
Published: December 2008

Neuronal cell adhesion molecules of the immunoglobulin superfamily (IgCAMs) play a crucial role in the formation of neural circuits at different levels: cell migration, axonal and dendritic targeting as well as synapse formation. Furthermore, in perinatal and adult life, neuronal IgCAMs are required for the formation and maintenance of specialized axonal membrane domains, synaptic plasticity and neurogenesis. Mutations in the corresponding human genes have been correlated to several human neuronal disorders. Perturbing neuronal IgCAMs in animal models provides powerful means to understand the molecular and cellular basis of such human disorders. In this review, we concentrate on the NCAM, L1 and contactin subfamilies of neuronal IgCAMs summarizing recent functional studies from model systems and highlighting their links to disease pathogenesis.
Adeno‐associated virus‐mediated gene delivery approaches for the treatment of CNS disorders
Authors: Terzi Dimitra , Zachariou Venetia
Published: December 2008

Over the last few years, a large number of preclinical and clinical studies have demonstrated the potential of gene therapy applications using adeno‐associated viral (AAV) vectors. Gene transferviaAAV vectors has been particularly successful for the treatment or adjunct therapy of several CNS disorders. The present review summarizes the progress on AAV gene delivery models for three different CNS disorders. In particular, we discuss advances in AAV‐mediated gene transfer strategies in animal models of Parkinson's disease, Alzheimer's disease and spinal cord trauma and summarize the results from the first clinical studies using AAV systems.
Überlastetes Ökosystem Erde. Wie der Mensch über seine Verhältnisse lebt
Authors: Fritsche Wolfgang
Published: December 2008

Die wichtigste Grundlage für die natürlichen Existenzbedingungen des Menschen sind die ökosystemaren Leistungen, die auf der Struktur und Funktion natürlicher und naturnaher Ökosysteme beruhen. Ihr Wert wurde lange unterschätzt, sie galten als Gratisleistungen der Natur. Eine ökonomische Bewertung hat ergeben, dass ihr monetärer Wert über dem des globalen Bruttosozialproduktes liegt. Berechnungen des ökologischen Fußabdruckes zeigen eine etwa 30%ige Überbeanspruchung der Biokapazität der Erde an. Die globalen Stoffkreisläufe kompensieren nicht mehr die zusätzlichen anthropogenen Einträge. Zur Lösung der sich verschärfenden Umweltprobleme ist eine Integration der wirtschaftlichen Aktivitäten in die natürlichen Kreisläufe notwendig.
Virtuelle Fachbibliothek schafft Übersicht. Bio‐Datenbanken und mehr in “vifabio”
Authors: Kasperek Gerwin
Published: December 2008

Die Virtuelle Fachbibliothek Biologie – kurz: vifabio – unterstützt beim Auffinden und Benutzen von biologischen Fachdatenbanken. Das Angebot umfasst drei Bausteine: einen Datenbank‐Führer, der hilft, die “richtigen” Datenbanken für die eigenen Fragestellungen zu finden, weiterhin Literatur‐Datenbanken, die mithilfe von Nationallizenzen zugänglich gemacht werden, sowie spezielle Zugänge für Benutzer außerhalb von Hochschulen.
Base‐Modified DNA Labeled by [Ru(bpy)3]2+ and [Os(bpy)3]2+ Complexes: Construction by Polymerase Incorporation of Modified Nucleoside Triphosphates, Electrochemical and Luminescent Properties, and Applications
Authors: Vrábel Milan , Horáková Petra , Pivoňková Hana , Kalachova Lubica , Černocká Hana , Cahová Hana , Pohl Radek , Šebest Peter , Havran Luděk , Hocek Michal , Fojta Miroslav
Published: December 2008

Modified 2′‐deoxynucleoside triphosphates (dNTPs) bearing [Ru(bpy)3]2+ and [Os(bpy)3]2+ complexes attached via an acetylene linker to the 5‐position of pyrimidines (C and U) or to the 7‐position of 7‐deazapurines (7‐deaza‐A and 7‐deaza‐G) have been prepared in one step by aqueous cross‐couplings of halogenated dNTPs with the corresponding terminal acetylenes. Polymerase incorporation by primer extension using Vent (exo‐) or Pwo polymerases gave DNA labeled in specific positions with Ru2+ or Os2+ complexes. Square‐wave voltammetry could be efficiently used to detect these labeled nucleic acids by reversible oxidations of Ru2+/3+ or Os2+/3+. The redox potentials of the Ru2+ complexes (1.1–1.25 V) are very close to that of G oxidation (1.1 V), while the potentials of Os2+ complexes (0.75 V) are sufficiently different to enable their independent detection. On the other hand, Ru2+‐labeled DNA can be independently analyzed by luminescence. In combination with previously reported dNTPs bearing ferrocene, aminophenyl, and nitrophenyl tags, the Os‐labeled dATP has been successfully used for “multicolor” redox labeling of DNA and for DNA minisequencing.
Palladium‐Nanoparticle‐Catalysed Ullmann Reactions in Ionic Liquids with Aldehydes as the Reductants: Scope and Mechanism
Authors: Calò Vincenzo , Nacci Angelo , Monopoli Antonio , Cotugno Pietro
Published: December 2008

An efficient Ullmann‐type reductive homocoupling of aryl, vinyl and heteroaryl halides can be promoted by an aldehyde in tetraalkylammonium ionic liquids under very mild reaction conditions. This simple procedure generates symmetrical biaryls under relatively mild conditions. The ionic liquid is crucial for this process because it behaves simultaneously as a base, ligand and reaction medium. The role of the aldehyde is also discussed and a general mechanism for this unusual reaction is proposed. These results open the way to a new efficient method of Pd‐catalysed dehydrogenation of carbonyl compounds.
Self‐Assembled Heavy Lanthanide Orthovanadate Architecture with Controlled Dimensionality and Morphology
Authors: Qian Liwu , Zhu Jun , Chen Zhu , Gui Yicai , Gong Qiang , Yuan Yanping , Zai Jiantao , Qian Xuefeng
Published: December 2008

Nearly monodisperse YVO4 architectures with persimmon‐like, cube‐like and nanoparticle shapes have been synthesised on a large scale by means of a complexing‐agent‐assisted solution route. The shape and size of these as‐prepared architectures can be tuned effectively by controlling the reaction conditions, such as reaction time, the molar ratio of complexing agent/Y3+ and different complexing agents. As a typical morphology, the growth process of monodisperse nanopersimmons has been examined. To extend this method, other LnVO4 (Ln=Ce, Gd, Dy, Er) complexes with well‐defined shape and dimensionality can also be achieved by adjusting different rare earth precursors. Further studies reveal that the morphology of the as‐synthesised lanthanide orthovanadate is determined mainly by the interaction between rare earth ion and the complexing agent. Ultraviolet (UV) absorption and photoluminescence spectra show that the optical properties of YVO4 nanopersimmons are relevant to their size and shape. This work sheds some light on the design of well‐defined complex nanostructures, and explores the potential applications of the as‐synthesised architectures.
Enantioselective Hydrogenation and Transfer Hydrogenation of Bulky Ketones Catalysed by a Ruthenium Complex of a Chiral Tridentate Ligand
Authors: Díaz‐Valenzuela M. Belén , Phillips Scott D. , France Marcia B. , Gunn Mary E. , Clarke Matthew L.
Published: December 2008

A study on the enantioselective hydrogenation of tertiary alkyl ketones catalysed by a novel class of tridentate–Ru complex is reported. In contrast to the extensively studied [RuCl2(diphos)(di‐primary amine)] complexes, this new class of hydrogenation catalyst smoothly reduces these less reactive bulky ketones with up to 94 % ee. The same catalyst system can also selectively reduce other potentially problematic substrates such as bulky heterocyclic ketones. Unusually for a pressure hydrogenation catalyst, similar enantioselectivity can be obtained under transfer hydrogenation conditions. The transfer hydrogenations are somewhat slower than the pressure hydrogenations, but this drawback is readily overcome, since we have discovered that a microwave accelerated transfer hydrogenation of the above ketones occurs within 20 min at about 90 °C with similar selectivity to that obtained in the pressure hydrogenation system.
In vitro and in vivo Staining Characteristics of Small, Fluorescent, Aβ42‐Binding D‐Enantiomeric Peptides in Transgenic AD Mouse Models
Authors: van Groen Thomas , Kadish Inga , Wiesehan Katja , Funke Susanne A. , Willbold Dieter
Published: December 2008

Plaque visualisation: We identified three different D‐enantiomeric peptides that bind to Alzheimer's amyloid β (Aβ1‐42). As there is currently no definitive pre‐mortem diagnosis for Alzheimer's disease, we investigated the peptides' suitability as molecular probes for in vivo imaging in transgenic mouse models.

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One of the characteristic pathological hallmarks of Alzheimer's disease (AD) are neuritic plaques that consist of amyloid peptide (Aβ). To improve diagnosis and treatment evaluation, neuroimaging tools that make use of Aβ‐binding ligands to visualise amyloid plaques are being developed. We investigate the in vitro and in vivo characteristics of a series of three D‐enantiomeric peptides (D1–D3) that were developed to specifically bind amyloid β1‐42 (Aβ42) in the brains of transgenic AD‐model mice. We stained brain sections of the mice, injected and infused the mice with these small D‐peptides, and examined their staining of Aβ42 in the brain. The experiments demonstrate that the D‐peptides label all plaques that contain Aβ42 in the brain. In contrast, diffuse amyloid β deposits (which do not contain Aβ42) are not stained by any of the D‐peptides. The in vivo and in vitro studies demonstrate that the D‐peptides label all Aβ42 in the brain, and none of the D‐peptides causes inflammation or is taken up by astrocytes or microglia. Furthermore, long‐term infusion of the peptides does not cause inflammation. Together, this demonstrates that these D‐peptides might be suitable for use as molecular probes to measure Aβ plaque load in the living brain for early diagnosis of Alzheimer's disease, or to monitor Aβ42 plaque load during disease progression or during treatment.
NG‐Acylated Aminothiazolylpropylguanidines as Potent and Selective Histamine H2Receptor Agonists
Authors: Kraus Anja , Ghorai Prasanta , Birnkammer Tobias , Schnell David , Elz Sigurd , Seifert Roland , Dove Stefan , Bernhardt Günther , Buschauer Armin
Published: December 2008

Bioisosteric replacementof the guanidino group in arpromidine‐like histamine H2receptor (H2R) agonists by an acylguanidine moiety is useful for obtaining potent H2R agonists with improved oral bioavailability and blood–brain barrier penetration. We show that bioisosteric replacement of the imidazole ring in NG‐acylated imidazolylpropylguanidines by a 2‐aminothiazol‐5‐yl group resulted in potent H2R agonists with much greater selectivity for the human H2R over H3and H4receptors.

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The bioisosteric replacement of the guanidino group in arpromidine‐like histamine H2receptor (H2R) agonists by an acylguanidine moiety is a useful approach to obtain potent H2R agonists with improved oral bioavailability and blood–brain barrier penetration. Unfortunately, the selectivity of such NG‐acylated imidazolylpropylguanidines for the H2R is poor, in particular versus histamine H3(H3R) and H4receptors (H4R). This drawback appears to depend on the “privileged” imidazolylpropylguanidine structure. The 2‐amino‐4‐methylthiazol‐5‐yl moiety is a bioisostere of the imidazole ring in the moderately potent H2R‐selective histamine analogue amthamine. This approach was successfully applied to acylguanidine‐type H2R agonists. The aminothiazoles are nearly equipotent to the corresponding imidazoles as H2R agonists. Compared with histamine, the potency is increased up to 40‐fold on the guinea pig right atrium, and up to 125‐ and 280‐fold in GTPase assays with human and guinea pig H2R–GsαSfusion proteins expressed in Sf9 insect cells, respectively. Docking studies on H2R models support the hypothesis that 2‐aminothiazolyl and imidazolyl derivatives interact with H2Rs as bioisosteres. In contrast to the imidazoles, the aminothiazoles are devoid of agonistic or relevant antagonistic effects on H1, H3, and H4receptors. Moreover, unlike amthamine, the 4‐methyl group does not significantly contribute to the H2R agonism of NG‐acylated 2‐amino‐4‐methylthiazol‐5‐ylpropylguanidines.
Toward Docking‐Based Virtual Screening for Discovering Antitubulin Agents by Targeting Taxane and Colchicine Binding Sites
Authors: Soulère Laurent
Published: December 2008

Docking‐based virtual screening: Flexible docking, scoring, and virtual screening of ligand databases are on the way to fulfilling the promise. Docking‐based virtual screening that targets taxane and colchicine binding sites will certainly provide new antitubulin agents.

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Tubulin proteins play a major role in cell division, and were first identified as attractive targets for cancer therapy over 40 years ago. Recent studies aiming to gain structural insight into the binding mode of antitubulin agents to taxane or colchicine binding sites using NMR and/or molecular‐mechanics‐assisted conformation analysis and docking simulations have been reported. These studies, which represent the main focus of this article, create prospects for the development of docking‐based virtual screening techniques to aid in the discovery of new antitubulin agents.
Photophysics of New Water‐Soluble Terrylenediimide Derivatives and Applications in Biology
Authors: Jung Christophe , Ruthardt Nadia , Lewis Robert , Michaelis Jens , Sodeik Beate , Nolde Fabian , Peneva Kalina , Müllen Klaus , Bräuchle Christoph
Published: December 2008

The photophysical properties of three new water‐soluble terrylenediimide (WS‐TDI) derivatives are investigated and their utilization in biological experiments is demonstrated. Each of these dyes can be excited in the far red region of the visible spectrum, making them good candidates for in‐vivo studies. Single‐molecule techniques characterize their photophysics that is, the number of emitted photons, blinking characteristics and survival times until photobleaching takes place. All three dyes exhibit bright fluorescence, as well as an extremely high resistance against photodegradation compared to other well‐known fluorophores. Due to their different characteristics the three new WS‐TDI derivatives are suitable for specialized biological applications. WS‐TDI dodecyl forms non‐fluorescent aggregates in water which can be disrupted in a hydrophobic environment leading to a monomeric fluorescent form. Due to its high lipophilicity WS‐TDI dodecyl anchors efficiently in lipid bilayers with its alkyl chain and hence can be ideally used to image membranes and membrane‐containing compartments in living cells. In contrast, the positively charged WS‐TDI pyridoxy is a new type of chromophore in the WS‐TDI family. It is fully solubilized in water forming fluorescent monomers and is successfully used to label the envelope of herpes simplex viruses. Finally, it is shown that a WS‐TDI derivative functionalized with N‐hydroxysuccinimide ester moiety (WS‐TDI/NHS ester) provides a versatile reactive dye molecule for the specific labelling of amino groups in biomolecules such as DNA.
How Does a Membrane Protein Achieve a Vectorial Proton Transfer Via Water Molecules?
Authors: Wolf Steffen , Freier Erik , Gerwert Klaus
Published: December 2008

We present a detailed mechanism for the proton transfer from a protein‐bound protonated water cluster to the bulk water directed by protein side chains in the membrane protein bacteriorhodopsin. We use a combined approach of time‐resolved Fourier transform infrared spectroscopy, molecular dynamics simulations, and X‐ray structure analysis to elucidate the functional role of a hydrogen bond between Ser193 and Glu204. These two residues seal the internal protonated water cluster from the bulk water and the protein surface. During the photocycle of bacteriorhodopsin, a transient protonation of Glu204 leads to a breaking of this hydrogen bond. This breaking opens the gate to the extracellular bulk water, leading to a subsequent proton release from the protonated water cluster. We show in detail how the protein achieves vectorial proton transfer via protonated water clusters in contrast to random proton transfer in liquid water.
Synthesis, Crystal Structures, and Thermal Properties of New [ZnX2(2,5‐dimethylpyrazine)] (X = Cl, Br, I) Coordination Compounds
Authors: Wriedt Mario , Jeß Inke , Näther Christian
Published: December 2008

Eight new halidozinc(II) coordination compounds with 2,5‐dimethylpyrazine as a ligand were prepared. The reaction of ZnX2 (X = Cl, Br, I) and 2,5‐dimethylpyrazine in methanol results in the formation of catena‐(μ2‐2,5‐dimethylpyrazine‐N,N′)dichloridozinc(II) (1), catena‐(μ2‐2,5‐dimethylpyrazine‐N,N′)dibromidozinc(II) (3I and 3II), catena‐(μ2‐2,5‐dimethylpyrazine‐N,N′)diiodidozinc(II) (6), and diiodidobis(2,5‐dimethylpyrazine‐N)zinc(II) (7). In addition, in a solvent‐free reaction of ZnX2 (X = Cl, Br) and 2,5‐dimethylpyrazine,the ligand‐rich compounds bis(dichlorido)bis(2,5‐dimethylpyrazine‐N)(μ2‐2,5‐dimethylpyrazine‐N,N′)dizinc(II) (2), bis(dibromido)bis(2,5‐dimethylpyrazine‐N)(μ2‐2,5‐dimethylpyrazine‐N,N′)dizinc(II) (4), and dibromidobis(2,5‐dimethylpyrazine‐N)zinc(II) 2,5‐dimethylpyrazine solvate (5) were obtained. In the crystal structures of all compounds the zinc atoms are each coordinated by two halide atoms and two 2,5‐dimethylpyrazine ligands within a distorted tetrahedron. The zinc atoms in the ligand‐deficient 1:1 (1:1 = molar ratio of metal salt to ligand) compounds 1 and 6 and in the two polymorphic modifications 3I and 3II are linked by the N‐donor ligands into chains. In contrast, the crystal structure of the 2:3 compounds 2 and 4 are built up of oligomeric discrete [(ZnX2)2(2,3‐dimethylpyrazine)3] units in which each ZnX2 (X = Cl, Br) unit is coordinated by two halide atoms and one bridging and one terminal 2,5‐dimethylpyrazine ligand. The structures of the ligand‐rich 1:2 diiodido compound 7 and the 1:3 dibromido compound 5 consist of discrete monomeric tetrahedral building blocks. In the thermal decomposition reactions of the ligand‐rich compounds 2, 5, and 7, different mass steps are observed. In the first step, the ligand‐deficient 1:1 compounds 1 and 6 are formed in quantitative yields from 2 and 7, respectively, and 5 yields a mixture of 3I and 3II, and the second mass step leads to the formation of new ligand‐deficient 2:1 compounds. On further heating of the compounds, the remaining ligands are discharged. This results in the formation of the zinc(II) halides, which vaporize on further heating. Solvent‐mediated conversion experiments in methanol show that, irrespective of the ratio of zinc(II) halide and ligand, only the 1:1 compounds 1 and 3I are formed and therefore represent the thermodynamically most stable compounds at room temperature. For ZnI2 the 1:2 compound 7 is obtained at ratios of zinc(II) iodide to ligand larger than 1:3, whereas at lower ratios the 1:1 compound 6 is always obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Mercury speciation by CE: An update
Authors: Kubánˇ Petr , Pelcová Pavlína , Margetínová Jana , Kubánˇ Vlastimil
Published: December 2008

This review provides an update on mercury speciation by CE. It includes a brief discussion on physicochemical properties, toxicity and transformation pathways of mercury species (i.e. methyl‐, ethyl‐, phenyl‐ and inorganic mercury) and outlines recent trends in Hg speciation by CE. CE is presented as a complementary technique to chromatographic separation techniques, especially in cases when speed, high efficiency and low sample volumes are required. The development of suitable sample preconcentration/isolation (sample stacking, ion exchange, liquid–liquid–liquid extraction, dual‐cloud point extraction) to achieve low LODs for analysis of trace concentrations of mercury species in real samples is emphasized. Hyphenation of CE to element specific detectors (i.e. electrothermal atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma‐optical emission spectrometry, inductively coupled plasma‐mass spectrometry) is discussed as well as a potential of CE in interaction studies that may provide useful information on interaction of various Hg species with selected bio‐macromolecules.
Recent developments of molecularly imprinted polymer in CEC
Authors: Huang Yan‐Ping , Liu Zhao‐Sheng , Zheng Chao , Gao Ru‐Yu
Published: December 2008

This review focuses on developments in the field of molecularly imprinted polymer (MIP) for CEC since August 2006. New technique of CEC‐based MIP, e.g. covalent approach through the formation of Schiff base, miniemulsion polymerization, non‐hydrolytic sol–gel methodology, MIP‐derivatized silica monolithic column, are discussed from the view of MIP preparation. Some thoughts on potential future directions are also expressed in this review.
Temperature dependence of time domain reflectometry–measured soil dielectric permittivity
Authors: Skierucha Wojciech
Published: December 2008

The purpose of this study is to determine the temperature influence on the soil bulk dielectric permittivity, ϵb, calculated from the measurement of the electromagnetic‐wave velocity of propagation along the parallel waveguide in a TDR probe, i.e., a probe working in time domain reflectometry technique. The experimental evidence shows that the existing models do not completely describe the temperature effect. However, it has been confirmed that the observed temperature effect is the result of two competing phenomena: ϵb increases with temperature following the release of bound water from soil solid particles, and ϵb decreases with temperature increase following the temperature effect of free water molecules. It has been found that there is a soil type–characteristic moisture value, θeq, named the equilibrium water content, at which both competing phenomena compensate each other. The equilibrium water content, θeq, is correlated with the soil specific surface area. Based on knowledge of θeq, a temperature‐correction formula is presented that adjusts the TDR soil‐moisture measurements at various temperatures to the corresponding value at 25°C. This decreases the absolute measurement error of soil moisture, θTDR, by the factor of 2 as compared to the uncorrected values.
Simultaneous determination of three anticon‐vulsants using hydrophilic interaction LC‐MS
Authors: Oertel Reinhard , Arenz Norman , Pietsch Jörg , Kirch Wilhelm
Published: December 2008

A specific and automated method was developed to quantify the anticonvulsants gabapentin, pregabalin and vigabatrin simultaneously in human serum. Samples were prepared with a protein precipitation. The hydrophilic interaction chromatography (HILIC) with a mobile phase gradient was used to divide off ions of the matrix and for separation of the analytes. Four different HILIC‐columns and two different column temperatures were tested. The Tosoh‐Amid column gave the best results: single small peaks. The anticonvulsants were detected in the multiple reaction monitoring mode (MRM) with ESI‐MS‐MS. Using a volume of 100 μL biological sample the lowest point of the standard curve, i.e. the lower LOQs were 312 ng/mL. The described HILIC‐MS‐MS method is suitable for therapeutic drug monitoring and for clinical and pharmcokinetical investigations of the anticonvulsives.
Identification and quantification of the volatile constituents in Cnidium monnieri using supercritical fluid extraction followed by GC‐MS
Authors: Chen Qinhua , Li Peng , Yuan Fangjun , Cheng Fanjun , He Jing , Liu Jia , Zhang Zhuo
Published: December 2008

The volatile components of Cnidium monnieri were obtained by supercritical fluid extraction (SFE) and analyzed by GC‐MS (identification and determination of metabolites). The compounds were identified according to their retention times and mass spectra. The effects of different parameters, such as extraction pressure, temperature, dynamic extraction time, flow rate of CO2, on the SFE of C. monnieri extracts were investigated. A total of 14 compounds of SFE extracts were identified. Osthole (69.52%), bornyl acetate (10.03%), α‐pinene (4.71%), and imperatorin (2.42%) were the major compounds identified in C. monnieri SFE extracts. The quantitation of osthole and imperatorin were then accomplished. The linear calibration ranges were all 5–1000 μg/mL for osthole and imperatorin by GC‐MS analysis. The recovery of osthole and imperatorin were in the range 96.5–101.8%. The LODs for osthole and imperatorin were 1.0 and 0.6 μg/mL, respectively.
Intuitionistic notions of boundedness in ℕ
Authors: Richman Fred
Published: December 2008

We consider notions of boundedness of subsets of the natural numbers ℕ that occur when doing mathematics in the context of intuitionistic logic. We obtain a new characterization of the notion of a pseudobounded subset and we formulate the closely related notion of a detachably finite subset. We establish metric equivalents for a subset of ℕ to be detachably finite and to satisfy the ascending chain condition. Following Ishihara, we spell out the relationship between detachable finiteness and sequential continuity. Most of the results do not require countable choice. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tall cardinals
Authors: Hamkins Joel D.
Published: December 2008

A cardinal κ is tall if for every ordinal θ there is an embedding j: V → M with critical point κ such that j (κ) > θ and Mκ ⊆ M. Every strong cardinal is tall and every strongly compact cardinal is tall, but measurable cardinals are not necessarily tall. It is relatively consistent, however, that the least measurable cardinal is tall. Nevertheless, the existence of a tall cardinal is equiconsistent with the existence of a strong cardinal. Any tall cardinal κ can be made indestructible by a variety of forcing notions, including forcing that pumps up the value of 2κ as high as desired. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)