bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecularly Imprinted Polymers
Authors: Sellergren Börje , Hall Andrew J.
Published: February 2012

Molecular imprinting—or templating at a molecular level—allows the preparation of synthetic polymers featuring receptor or catalytically active sites. The most common form of imprinting comprises the synthesis of reticulated polymers in the presence of templates which, widely defined, may range from ions and small molecules to biological macromolecules and ultimately microorganisms. Functional monomers act as anchors interacting with the template and holding it in place during the polymerization. Removal of the template from the formed polymer liberates binding sites complementary in shape and binding groups to the template structure. This review starts by outlining the main synthetic concepts underlying the design of imprinted polymers and thereafter highlights key contributions devoted to various molecular recognition‐based applications.
Supramolecular Chemistry in Polymer Networks
Authors: Besenius Pol , Cormack Peter A. G.
Published: February 2012

Cross‐linked organic materials or polymer networks have found numerous applications and technologies that are indispensable in everyday life. Networks formed via molecular recognition events that act as noncovalent cross‐linkers exhibit rather unusual properties due to the dynamic character and tunable strength of the supramolecular interactions. In the first instance, we aim to introduce and discuss complementary functional groups that have been developed to allow for reversible network formation in bulk supramolecular materials. Thereafter, this chapter deals mainly with network formation in macroscopic and particulate gels. In both parts, we highlight how material properties at the meso‐ and macroscopic scales are governed by noncovalent forces on the molecular level, and how supramolecular interactions can offer opportunities in the fabrication of stimuli‐responsive materials. Lead examples and applications are highlighted throughout, for example, in the development of thermoplastic elastomers, coatings, tissue engineering, and drug delivery technologies.
Physisorption for Self‐Assembly of Supramolecular Systems: A Scanning Tunneling Microscopy Perspective
Authors: Mali Kunal S. , Adisoejoso Jinne , De Cat Inge , Balandina Tanya , Ghijsens Elke , Guo Zongxia , Li Min , Sankara Pillai Mahesh , Vanderlinden Willem , Xu Hong , De Feyter Steven
Published: February 2012

The objective of this chapter is to provide a brief account of the progress in the understanding of physisorbed monolayers through illustration of some key examples from contemporary literature. The discussion is limited to the self‐assembly of weakly adsorbed molecules at the liquid–solid interface as studied by scanning probe microscopy methods, especially scanning tunneling microscopy (STM). The fundamental aspects governing the formation and stabilization of physisorbed monolayers at the liquid–solid interface, such as influence of substrate, solvent, and temperature are highlighted. Special attention is also given to template‐directed self‐assembly, nanoporous and multicomponent surface networks, as well as surface chirality. Apart from its utility as a valuable tool to visualize matter down to atomic scale, the role of STM in comprehending fundamental physical and chemical phenomena such as molecular dynamics, electronics, and reactivity is also reviewed. This chapter could be equally appealing to both industry as well as academia since physisorbed monolayers at liquid–solid interfaces play a very important role in a number of industrially relevant processes and are also of intense academic interest due to the possibilities in surface nanoengineering and functionalization.
Chemisorbed Self‐Assembled Monolayers
Authors: Azzaroni Omar , Salvarezza Roberto C.
Published: February 2012

A review of the fundamental aspects of chemisorbed self‐assembled monolayers (SAMs), as a tool for building complex molecular systems on solid surfaces, is presented. Using alkanethiols, SAMs, as model systems the self‐assembly, surface structures, and SAM stability under different experimental conditions are discussed. We also point out the characteristics of SAMs that make them suitable especially for building active micro‐ and nanostructured molecular systems on surfaces, and stress their limitations resulting from defects, contaminants, and disorder. Finally, we show examples of interfacial architectures drawn from supramolecular and covalent systems to illustrate the potential of SAMs as robust platforms for building functional 3D structures on solid substrates.
Liquid Crystals Formed from Specific Supramolecular Interactions
Authors: Bruce Duncan W.
Published: February 2012

This chapter presents a critical overview of the use of specific, supramolecular interactions to induce liquid‐crystalline behavior where the presence of these interactions leads either to the induction of liquid crystallinity where this was not observed in the components separately, or to the modification of liquid crystal properties beyond that normally found in mixture systems. The chapter begins by accepting and discussing the fact that any observation of liquid‐crystalline behavior is a supramolecular phenomenon that depends on the presence of anisotropic dispersion forces. Some specific aspects to illustrate the point, for example, the induction of chiral phases from achiral components, are given. The main part of the chapter then discusses mesophase induction through quadrupolar interactions, charge transfer, hydrogen bonding, and halogen bonding, selecting examples of each to illustrate both the breadth of materials realized under each heading and also some of the issues that are important in the different approaches.
Self‐Assembly of Polymers into Soft Nanoparticles and Nanocapsules
Authors: Tang Jianbin , Zhu Dingcheng , Shen Youqing
Published: February 2012

The self‐assembly mechanisms of copolymers into nanostructures and their applications in nanomedicines have attracted increasing attention recently. The basis of the various aspects of this research area is the correlation of the polymer structures to the type and structural parameters of the nanostructures formed, which are the keys for researchers to design needed nanostructures for applications such as drug delivery. Along this line, this chapter briefly summarizes the principles of formation, theoretical predications of structural parameters, and the basic experimental aspects in preparation and characterization, as well as recent progress and applications of polymer micelles and vesicles in nanomedicine.
Replication Processes—From Autocatalysis to Systems Chemistry
Authors: Huck Jürgen , Philp Douglas
Published: February 2012

Chemical systems capable of templating and catalyzing their own synthesis — known as replicating systems — have started to appear in the chemical literature over the last 25 years. In a biological context, these systems represent a link with the origin of life, and their behavior could perhaps provide a model for prebiotic chemical evolution. For the synthetic chemist, they represent the ultimate synthetic machine, capable of directing the formation of a large number of identical copies of themselves from a single template molecule. One of the driving forces in this research area has been recognizing the important role that replication plays in biology and attempting to answer a fundamental question — “Is the structural complexity of nucleic acids necessary to store and transmit information at a molecular level”? In addition, the concept of a chemical template that is capable of making billions of exact copies of itself, given appropriate starting materials, is a highly attractive one for the emerging field of systems chemistry. The development of a detailed understanding of the behavior of replicating systems has important perspectives for both biology and chemistry.
Artificial Enzyme Mimics
Authors: Geibel Barbara , Merschky Michael , Rether Carolin , Schmuck Carsten
Published: February 2012

Enzymes are among the most effective catalysts known so far both in terms of their efficiency as well as selectivity. They can achieve rate accelerations of up to a factor of 1011and more, and sometimes react exclusively with only one single stereoisomer of a substrate if required. Enzymes make use of various different mechanisms of catalysis such as transition‐state binding, acid–base catalysis, nucleophilic catalysis, entropic control of reactions, and so on, with roughly half the known enzymes using metal ions while the other half solely relies on organic functional groups. Owing to these fascinating features of enzymes, chemists have tried to mimic enzymes early on developing artificial enzyme models. Over the years, a multitude of functional artificial enzyme models for very different types and classes of enzymes were developed, some closely mimicking the mode of action of their natural counterparts whereas others just adopt some general features found in enzymes. We briefly discuss some selected examples of artificial enzyme mimics in this review. Of course, the following examples are only a few picked out of a great variety. We do not attempt to provide a complete overview in respect to enzymes that are mimicked or models that were developed, but rather focus on the different approaches and concepts used to imitate an enzyme. The choice of examples is purely reflecting our personal preferences and is not implied to indicate that any work not mentioned is less interesting.

We have arranged the examples of enzyme mimics and presented roughly according to their increasing chemical and structural complexity, starting with simple metal complexes (Section 1), then discussing cyclodextrin and related enzyme mimics (Section 2) before focusing on polymer‐ and dendrimer‐derived systems (Section 3). Miniproteins and oligopeptides with defined structures are then discussed (Section 4) before we end with a brief description of catalytic antibodies (Section 5).
Reaction Networks
Authors: Dadon Zehavit , Wagner Nathaniel , Cohen‐Luria Rivka , Ashkenasy Gonen
Published: February 2012

The study of synthetic molecular networks is of fundamental importance for understanding the organizational principles of biological systems. An important family of the nonenzymatic systems uses template‐directed catalysis as a means of wiring the network components and controlling their dynamics and replication. As such, these networks have received considerable attention with respect to possible scenarios in the origins of life and early molecular evolution. In this review, we summarize recent studies aimed at the design and functional analysis of peptide‐based replicating networks. Design of the networks, by simultaneous implementation of autocatalysis and cross‐catalysis, is first explained. It is followed by detailing how one can simulate the complex networks' kinetics, and how it is possible to manipulate the catalytic processes and thus to control the entire network topology. At the end, we discuss the relevancy of these findings to the study of biochemical networks, such as RNA networks.
Reactivity in Nanoscale Vessels
Authors: Breiner Boris , Nitschke Jonathan R.
Published: February 2012

Reactivity in nanoscale vessels is based on host–guest chemistry, the “chemistry of the inner phase.” This term was coined by Cram to describe the mechanical entrapment of molecules within other molecules, and the new reactivity patterns that could be observed on this encapsulation. He quickly realized that encapsulated molecules showed behavior that was different from what was known about them in solution and concluded that molecules (“guests”) that were trapped inside another molecule (“host”) were in essence in a different state of matter. The field of host–guest chemistry has expanded drastically since his initial findings, and new reactions within the confines of a host are discovered at an ever‐increasing rate. We will try to put relevant findings into order, in an attempt to highlight common themes and to illustrate general trends.
Reactions in Dynamic Self‐Assemblies
Authors: Moulin E. , Giuseppone N.
Published: February 2012

The dynamic processes in self‐assemblies are involved in numerous domains that span throughout the modern aspects of chemical sciences, going from fundamental investigations into the origin of life to the most striking technological applications in medicine or electronics. This chapter aims at providing the reader with a brief overview of the concepts that link chemical reactivity with dynamic templates and catalysts made of large supramolecular assemblies. Specifically, we discuss kinetic and thermodynamic aspects of selected examples depending on (i) the nature of the matrix — that is, micelles, vesicles, liquid crystals, and gels; (ii) the nature of their constituents — that is, surfactants, block copolymers, bioactive macromolecules; and (iii) the nature of the chemical transformations that are performed — that is, reaction of small organic molecules, biomolecules, polymerizations, nanoparticle formation, and also reactions that involve the constituents of the matrix themselves as observed, for instance, in self‐reproducing systems. In each section, we combine original papers that paved the field together with more recent works of particular interest; several reviews are also referenced to help in accessing a more comprehensive literature.
Membrane Transport
Authors: Quesada Roberto
Published: February 2012

Membranes are not permeable to charged species, and facilitated ion transport is an essential cell function. Natural ion channels are mainly complex transmembrane proteins, and insights into the structure of these proteins have provided valuable hints for the design of synthetic ion transport mechanisms. Development of new transmembrane transporters has potential applications in medicinal chemistry (antibiotics, channel replacement therapies, and drug delivery) as well as cell biology research, catalysis, or sensing. In this article, synthetic model systems for the facilitated ion translocation in lipid bilayers are presented. Examples of ion channels, both unimolecular and self‐assembled channels as well as ion carriers provide an overview of successful designs and combinations of ion receptor interactions used to facilitate transmembrane transport.
Supramolecular Approaches to Medicinal Chemistry
Authors: Biros Shannon , Hof Fraser
Published: February 2012

This chapter describes how the central concept of molecular recognition links the distinct pursuits of supramolecular chemistry and drug development. Topics covered include the use of enzyme inhibitors as tools for measuring the strengths of weak interactions, the use of drug targets as templates for the formation of their own inhibitors (bothin situtemplated synthesis and dynamic combinatorial chemistry (DCC)), and the use of traditionally supramolecular scaffolds for the recognition of large protein surfaces.
Atomic Force Microscopy Measurements of Supramolecular Interactions
Authors: Song Bo , Schönherr Holger
Published: February 2012

Atomic force microscopy‐based single‐molecule force spectroscopy (SMFS) has matured in the past decade to become a reliable method to probe the rupture of individual supramolecular bonds and to analyze the strength of noncovalent interactions in a wide range of conditions. SMFS undoubtedly also has a major impact on the biophysical field, an area of research that will be excluded from our discussion. Instead, we focus attention on synthetic supramolecular systems. In this chapter, we summarize the fundamental experimental setup and design, discuss strategies to identify single‐molecule events, provide some rudimentary theory, and finally illustrate the power of the methodology by discussing selected examples. The examples encompass a broad range of interaction types, and hence interaction strengths and typical time scales, including hydrogen bonding, host–guest interactions, π–π interactions, hydrophobic interactions, and metal–ligand coordination. The force data for simple, binary complexes receive similar attention as highly complex supramolecular systems with multiple bond switches in parallel or in series. Finally, we mention areas of potential further development.
Two‐Dimensional Supramolecular Chemistry
Authors: Phillips Anna G. , Beton Peter H. , Champness Neil R.
Published: February 2012

Two‐dimensional assembly of molecular assemblies on surfaces represents a significant challenge to chemists, materials scientists, and physicists. Supramolecular chemistry offers many advantageous strategies for the development of such arrays through the use of intermolecular interactions to control the process of molecular organization and self‐assembly. This article reveals how hydrogen bonds, dipole–dipole, van der Waals interactions, and metal–ligand coordination can be used to assemble two‐dimensional arrays on surfaces. Such supramolecular assemblies can be used to trap guest species mimicking host–guest chemistry in the solution phase. By the use of the molecular resolution of scanning‐probe microscopies, particularly scanning tunneling microscopy, the precise arrangement of the supramolecular assemblies can be probed and evaluated including the relative orientation with respect to the surface. The influence of the surface on the self‐assembly process is discussed and it is shown that far from playing a passive role in the self‐assembly process the substrate can strongly influence the supramolecular chemistry observed. Such images provide great insight into the advantages and restrictions of working in two dimensions in comparison to the solution phase or the solid state.
Development and Application of Multiple‐Probe Scanning Probe Microscopes
Authors: Nakayama Tomonobu , Kubo Osamu , Shingaya Yoshitaka , Higuchi Seiji , Hasegawa Tsuyoshi , Jiang Chun‐Sheng , Okuda Taichi , Kuwahara Yuji , Takami Kazuhiro , Aono Masakazu
Published: February 2012

In the research of advanced materials based on nanoscience and nanotechnology, it is often desirable to measure nanoscale local electrical conductivity at a designated position of a given sample. For this purpose, multiple‐probe scanning probe microscopes (MP‐SPMs), in which two, three or four scanning tunneling microscope (STM) or atomic force microscope (AFM) probes are operated independently, have been developed. Each probe in an MP‐SPM is used not only for observing high‐resolution STM or AFM images but also for forming an electrical contact enabling nanoscale local electrical conductivity measurement. The world's first double‐probe STM (DP‐STM) developed by the authors, which was subsequently modified to a triple‐probe STM (TP‐STM), has been used to measure the conductivities of one‐dimensional metal nanowires and carbon nanotubes and also two‐dimensional molecular films. A quadruple‐probe STM (QP‐STM) has also been developed and used to measure the conductivity of two‐dimensional molecular films without the ambiguity of contact resistance between the probe and sample. Moreover, a quadruple‐probe AFM (QP‐AFM) with four conductive tuning‐fork‐type self‐detection force sensing probes has been developed to measure the conductivity of a nanostructure on an insulating substrate. A general‐purpose computer software to control four probes at the same time has also been developed and used in the operation of the QP‐AFM. These developments and applications of MP‐SPMs are reviewed in this paper.
Validation of the Charcot–Marie–Tooth disease pediatric scale as an outcome measure of disability
Authors: Burns Joshua , Ouvrier Robert , Estilow Tim , Shy Rosemary , Laurá Matilde , Pallant Julie F. , Lek Monkol , Muntoni Francesco , Reilly Mary M. , Pareyson Davide , Acsadi Gyula , Shy Michael E. , Finkel Richard S.
Published: February 2012

Objective:

Charcot–Marie–Tooth disease (CMT) is a common heritable peripheral neuropathy. There is no treatment for any form of CMT, although clinical trials are increasingly occurring. Patients usually develop symptoms during the first 2 decades of life, but there are no established outcome measures of disease severity or response to treatment. We identified a set of items that represent a range of impairment levels and conducted a series of validation studies to build a patient‐centered multi‐item rating scale of disability for children with CMT.

Methods:

As part of the Inherited Neuropathies Consortium, patients aged 3 to 20 years with a variety of CMT types were recruited from the USA, United Kingdom, Italy, and Australia. Initial development stages involved definition of the construct, item pool generation, peer review, and pilot testing. Based on data from 172 patients, a series of validation studies were conducted, including item and factor analysis, reliability testing, Rasch modeling, and sensitivity analysis.

Results:

Seven areas for measurement were identified (strength, dexterity, sensation, gait, balance, power, endurance), and a psychometrically robust 11‐item scale was constructed (CMT Pediatric Scale [CMTPedS]). Rasch analysis supported the viability of the CMTPedS as a unidimensional measure of disability in children with CMT. It showed good overall model fit, no evidence of misfitting items, and no person misfit, and it was well targeted for children with CMT.

Interpretation:

The CMTPedS is a well‐tolerated outcome measure that can be completed in 25 minutes. It is a reliable, valid, and sensitive global measure of disability for children with CMT from the age of 3 years. ANN NEUROL 2012;
Stroke recurrence in children with congenital heart disease
Authors: Rodan Lance , McCrindle Brian W. , Manlhiot Cedric , MacGregor Daune L. , Askalan Rand , Moharir Mahendra , deVeber Gabrielle
Published: February 2012

Objective:

Pediatric arterial ischemic stroke (AIS) carries an important morbidity and mortality burden. Congenital heart disease (CHD) is among the most important risk factors for pediatric AIS. Data on stroke recurrence in childhood CHD are lacking, resulting in uncertainty regarding optimal strategies for preventing recurrence.

Methods:

In the Canadian Pediatric Ischemic Stroke Registry–Toronto site, we identified children (birth to 18 years) with CHD diagnosed with AIS during 1992–2008. Data were abstracted from both stroke and cardiac surgery databases. Time‐dependent outcomes (death and recurrent stroke) following sentinel stroke were parametrically modeled in competing risk analysis. Factors predicting stroke recurrence in parametric survival models were sought in parametric survival model analyses using backward variable selection of variables.

Results:

A total of 135 patients (19 with recurrence, 116 without recurrence) were studied. In competing risk analysis, 10 years following sentinel stoke, 27% had experienced a stroke recurrence, 26% had died, and 47% were alive and free from recurrence. Stroke recurrence risk decreased over time from sentinel stroke. Approximately 50% of patients were receiving anticoagulation at recurrence. Significant factors associated with recurrence included the presence of a mechanical valve, prothrombotic condition, and an acute infection at the time of sentinel stroke. Hazard of mortality after recurrence was similar to mortality after sentinel stroke (hazard ratio, 1.3; p = 0.75).

Interpretation:

Stroke recurrence was relatively common in neonates and children with CHD. Identified groups of patients at increased risk may require more aggressive secondary prophylaxis, especially in the early poststroke period. ANN NEUROL 2012;72:103–111
Rapid synthesis and characterization of chitosan‐g‐poly(D,L‐lactide) copolymers with hydroxyethyl chitosan as a macroinitiator under microwave irradiation
Authors: Luo Binghong , Yang Jing , Zhao Jianhao , Hsu ChungEn , Li Jianhua , Zhou Changren
Published: February 2012

Hydroxyethyl chitosan (HECS) was first prepared by the reaction of 2‐chloroethanol with chitosan (CS). Then, CS‐g‐poly(D,L‐lactide) (PDLLA) copolymers were synthesized through the ring‐opening polymerization of D,L‐lactide with CS and HECS as the macroinitiators, respectively, under microwave irradiation. The optimal synthesis conditions obtained by an orthogonal experiment were as follows: microwave power = 10 W, temperature = 130°C, irradiation time = 15 min, and catalyst concentration = 0.05 mol %. The reactivity of CS was improved by hydroxyethylation, which contributed to a higher percentage of grafting. Compared with the conventional thermal polymerization, the microwave polymerization method showed a significantly higher polymerization rate and improved efficiency. An enhanced percentage of grafting ranging from 236.25 to 317.50%, and an average degree of polymerization of PDLLA side chains ranging from 13.25 to 24.17 were achieved under microwave irradiation when the value of nD,L‐lactide/nminoglucoside units was increased from 20 : 1 to 40 : 1. The higher percentage of grafting facilitated decreases in the crystallinity and thermal stability of the copolymers, which were attributed to the weakening intramolecular and intermolecular hydrogen bonds of CS. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Structure and molecular dynamics of multilayered polycarbonate/polystyrene films
Authors: Walczak M. , Ciesielski W. , Galeski A. , Potrzebowski M. J. , Regnier G. , Hiltner A. , Baer E.
Published: February 2012

Multilayered film polycarbonate/polystyrene (PC/PS) comprising 257 layers with total thickness 125 μm was made by coextrusion process. The nominal thickness of PC layers was 680 nm, and the nominal thickness of PS layers was 290 nm. Additionally, the control samples of PC and PS with the thickness of 125 μm were coextruded in the same way. There was reasonably good correlation between the PC and PS layers real thickness as measured by AFM and the estimated thickness determined from the processing parameters. Significant shift of glass transition temperature is observed in multilayer film: for PS component toward higher temperature while PC still being glassy and for PC toward lower temperature while PS being in rubbery phase. To investigate the amplitude and geometry of fast segmental motions, the LG‐CP NMR technique under fast magic‐angle spinning was used. 2D 13C1H LG‐CP spectra of PC, PS, and PC/PS 70/30 were recorded at various temperatures. Cross sections of aromatic carbons spectra show us the influence of PC on PS and vice versa. It gives us also the information about PS and PC segmental motion as a function of temperature: above the glass transition temperature of PS, the PC component of a multilayer film, although still being in glassy state, becomes more flexible. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Impact of microextrusion and addition of graphite nanoplatelets on bulk and surface mechanical properties of UHMWPE
Authors: Delgado‐Rangel Jose‐Alejandro , Addiego Frédéric , Eddoumy Fatima , Ahzi Saïd , Patlazhan Stanislav , Toniazzo Valérie , Ruch David
Published: February 2012

A new processing route for producing ultra‐high molecular weight polyethylene (UHMWPE) nanocomposite combining swelling in toluene, microextrusion, and compression‐molding was developed. Using this novel method, extruded neat UHMWPE (e‐PE), and extruded UHMWPE blended with 0.5 wt % of graphite nanoplatelets (e‐PE/g) were processed. UHMWPE was also processed by compression‐molding (PE) as reference material. Bulk mechanical behavior of the materials was evaluated by tensile, bending and impact tests, while surface mechanical behavior was assessed by scratch and sliding wear experiments. We found that e‐PE/g has a brittle tensile behavior in comparison with the two other grades. Bending and impact toughness increase in this order: PE ≈ e‐PE/g < e‐PE. Scratch behavior of the materials is quite similar, e‐PE has however the lowest friction coefficient, and hence, exhibits antifriction properties. The cumulative sliding energy increases in this order: e‐PE ≈ PE < e‐PE/g, indicating that e‐PE/g may have a lower wear resistance as compared to the two other materials. The combination of extrusion with compression‐molding caused the formation of well‐consolidated meso‐domains containing oriented chains. Such a new morphology is at the origin of the high tensile strength, high fracture toughness, and antifriction properties of e‐PE that appears like a promising material for medical or machine construction applications. The addition of graphite nanoplatelets induces a poor consolidation that resulted from the segregation of the fillers between powder grains of UHMWPE. This explains the brittle tensile behavior and the high cumulative sliding energy of the UHMWPE nanocomposite. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The structure of novel polyurethanes containing synthetic poly[(R,S)‐3‐hydroxybutyrate]
Authors: Brzeska Joanna , Dacko Piotr , Gębarowska Katarzyna , Janik Helena , Kaczmarczyk Bożena , Kasperczyk Janusz , Kowalczuk Marek , Rutkowska Maria
Published: February 2012

The aim of this study was to estimate the structure of new polyurethanes with the potential to be used in medicine. Atactic poly[(R,S)‐3‐hydroxybutyrate], obtained via a ring‐opening polymerization, and polycaprolactonediol or polyoxytetramethylenediol were used to built the soft segments. 4,4′‐methylene dicyclohexyl diisocyanate and 1,4‐butanediol were the components to form hard segments. At FTIR spectra of obtained polyurethanes the bands attributed to NCO groups completely disappeared, similarly as these of OH groups and the new band characteristic for stretching vibrations of bonded urethane NH groups appeared. Polyurethanes with low‐molecular weight were obtained. The observation of FTIR and 1H‐NMR spectra had been suggested that NH groups form two types of hydrogen bonds: with CO urethane (possibly with ester group) and ether groups. An addition of poly[(R,S)‐3‐hydroxybutyrate] caused the slight increase in number of urethane–urethane hydrogen bonds. For some of polyurethanes (based on polyoxytetramethylenediol) the allophanate structures were obtained. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
CHARACTERIZATION OF GLUCOSE‐INDUCED GLUCOSE OXIDASE GENE AND PROTEIN EXPRESSION IN Helicoverpa armigera LARVAE
Authors: Tang Qingbo , Hu Yonghong , Kang Le , Wang Chen‐Zhu
Published: March 2012

Caterpillar labial salivary enzyme glucose oxidase (GOX) plays an important role in plant–insect interactions by suppressing the caterpillar‐induced nicotine production in tobacco plants. In the present study, we cloned and characterized the GOX gene (HaGox) from labial salivary glands of Helicoverpa armigera larvae using 3′ and 5′ RACE, homologous analysis, phylogenetic analysis, LC‐MS/MS, and qRT‐PCR. The deduced GOX amino acid sequence (606 amino acids) shares 99% and 76% identity with H. zea and Spodoptera exigua GOX, respectively, and is consistent with the GOX protein sequence identified from H. armigera labial salivary gland. These results confirmed that the HaGox encode the GOX protein. Transcript levels of HaGox in larval labial salivary glands were significantly higher than those in midgut and hemolymph, respectively, and those of caterpillars reared on tobacco leaves coated with 0.1%, 1%, and 10% glucose solutions were significantly higher than those reared on 0.01% glucose‐coated leaves or control tobacco leaves. Western blot and native PAGE showed that GOX protein expression levels and GOX enzymatic activities also increased with dietary glucose. These results proved that GOX expressions in larval labial salivary glands induced by dietary glucose were exhibited not only on transcriptional levels, but also on translational/posttranslational levels. © 2012 Wiley Periodicals, Inc.
Cross‐Coupling of Aryllithiums with Aryl and Vinyl Halides in Flow Microreactors
Authors: Nagaki Aiichiro , Moriwaki Yuya , Haraki Suguru , Kenmoku Akira , Takabayashi Naofumi , Hayashi Atsushi , Yoshida Jun‐Ichi
Published: February 2012

The use of Pd catalysts that contained a carbene ligand, such as PEPPSI‐SIPr, speeded up the Murahashi coupling of ArLi with ArBr, by enabling its integration with the Br/Li exchange of ArBr with BuLi in flow. Space integration realized the rapid cross‐coupling of two different ArBr substrates. However, the cross‐coupling reaction with vinyl halides could not be achieved under similar conditions. Pd(OAc)2 was an effective catalyst, and the space integration of the Br/Li exchange of ArBr with BuLi and the Murahashi coupling with vinyl halides was successfully achieved.
Biotechnological production of succinic acid: current state and perspectives
Authors: Cheng Ke‐Ke , Zhao Xue‐Bing , Zeng Jing , Zhang Jian‐An
Published: February 2012

Succinic acid has multiple practical applications (e.g. synthesis of 1,4‐butanediol, tetrahydrofuran, gamma‐butyrolactone, and as a monomer of some biodegradable polymers). Bio‐based succinic acid is a potential substitute for current petrochemical production. Facing a shortage of crude oil supply and sharply rising oil prices, biological production of succinic acid from abundant and available biomass has become a topic of worldwide interest. Although great progress has been made in recent decades, much needs to be developed further in order to achieve economic viability. This paper reviews developments in technology and updates research progress of biosuccinate production, including pathways, micro‐organisms, culture conditions, as well as integrated production with other high‐value‐added products. Finally, strategies are proposed for successful commercialization of fermentative succinic acid production. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Motivation as Mediator Between National Identity and Intention to Volunteer
Authors: Lai Mark H. C. , Ren Maggie Y. W. , Wu Anise M. S. , Hung Eva P. W.
Published: February 2012

Although there is a large volume of research on the relationship between social identity and volunteerism, little attention was given to national identity in volunteerism research. This study examined the role of national identity in motivating people to volunteer in the Chinese culture and its role in differentiating those who showed no interest in voluntary work (i.e. non‐volunteers) from those who wanted to volunteer but did not (i.e. potential volunteers). Two hundred ninety‐nine participants (age, M = 34.14 years) filled out a questionnaire on their demographics, experience of volunteering, intention to volunteer, volunteer motivations, and national identity. Results showed that a stronger national identity was associated with greater volunteer motivations. Mediation analyses further supported the positive indirect effect of national identity on intention to volunteer through strengthening volunteer motivations. Marital status was the only significant factor that differentiated current volunteers from potential volunteers. We concluded that citizens’ volunteer motivation increases with national identity, yet concrete measures to bring potential volunteers to actual volunteering need to be further explored. Copyright © 2012 John Wiley & Sons, Ltd.
Assessments and admissions during the first 6 years of a UK medium secure DSPD service
Authors: Freestone Mark , Taylor Celia , Milsom Sophia , Mikton Chris , Ullrich Simone , Phillips Ophelia , Coid Jeremy
Published: February 2012

Background

Offenders with personality disorder represent a considerable burden on mental health and criminal justice services. Millfields Unit was one of the pilot medium secure units (MSUs) established by the UK Department of Health and Ministry of Justice to provide dedicated services for such individuals.

Aims

Our study aimed to describe a complete cohort of referrals made to the service and to explore decisions on admissions to the Unit.

Methods

File review was used to collect a structured data set of information on the first 158 referrals. These were then analysed descriptively and inferentially.

Results

Previous psychological treatment in prison and evidence of motivation for further treatment were the strongest predictors of admission to the service. People admitted showed evidence of more extensive criminal histories, prior treatment failure and higher level of risk than those accepted into conventional medium secure units. Despite the stated purpose of the units being for people with personality disorder, a high number of patients with a primary diagnosis of psychotic illness were referred.

Conclusion

The new service accepted a high‐risk group of people with personality disorder whose needs would not otherwise have been met. Copyright © 2012 John Wiley & Sons, Ltd.
Amidetriazole: A Versatile Building Block for Construction of Oxyanion Anion Receptors
Authors: Li Yong‐Jun , Xu Liang , Yang Wen‐Long , Liu Hui‐Biao , Lai Siu‐Wai , Che Chi‐Ming , Li Yu‐Liang
Published: February 2012

The design and synthesis of efficient receptors for tetrahedral oxyanions is an emerging field in supramolecular chemistry. Herein, we have developed a urea‐like anion‐recognizing motif, amidetriazole, which can be easily synthesized and derived and shows good solubility. A series of simple acyclic receptors were designed and synthesized to confirm the potential of amidetriazole for the construction of tetrahedral oxyanion receptors. This molecular platform can be used extensively for the construction of numerous receptor systems appended with functional groups, which opens the way to many applications in the field of supramolecular chemistry.
Simulation of ultrasonic wave propagation in anisotropic poroelastic bone plate using hybrid spectral/finite element method
Authors: Nguyen Vu‐Hieu , Naili Salah
Published: February 2012

This paper deals with the modeling of guided waves propagation in in vivo cortical long bone, which is known to be anisotropic medium with functionally graded porosity. The bone is modeled as an anisotropic poroelastic material by using Biot's theory formulated in high frequency domain. A hybrid spectral/finite element formulation has been developed to find the time‐domain solution of ultrasonic waves propagating in a poroelastic plate immersed in two fluid halfspaces. The numerical technique is based on a combined Laplace–Fourier transform, which allows to obtain a reduced dimension problem in the frequency–wavenumber domain. In the spectral domain, as radiation conditions representing infinite fluid halfspaces may be exactly introduced, only the heterogeneous solid layer needs to be analyzed by using finite element method. Several numerical tests are presented showing very good performance of the proposed procedure. A preliminary study on the first arrived signal velocities computed by using equivalent elastic and poroelastic models will be presented.Copyright © 2012 John Wiley & Sons, Ltd.
A note on the null condition for quadratic nonlinear Klein‐Gordon systems in two space dimensions
Authors: Katayama Soichiro , Ozawa Tohru , Sunagawa Hideaki
Published: March 2012

We consider the Cauchy problem for quadratic nonlinear Klein‐Gordon systems in two space dimensions with masses satisfying the resonance relation. Under the null condition in the sense of J.‐M. Delort, D. Fang, and R. Xue (J. Funct. Anal. 211 (2004), no. 2, 288–323), we show the global existence of asymptotically free solutions if the initial data are sufficiently small in some weighted Sobolev space. Our proof is based on an algebraic characterization of nonlinearities satisfying the null condition. © 2012 Wiley Periodicals, Inc.
Broad near‐infrared fluorescence properties of Nd‐doped PbClF crystals
Authors: Wang Qingguo , Su Liangbi , Li Hongjun , Zheng Lihe , Xu Xiaodong , Wu Feng , Tang Huili , Jiang Dapeng , Chen Weichao , Xu Jun
Published: March 2012

Nd‐doped PbClF crystals were grown with modified Bridgman method. Broad and flat emission band at 1.0 μm was observed. The FWHM value of 0.0091 wt.% Nd3+‐doped PbClF crystal at 1064 nm reached up to 30 nm with the peak emission cross‐section of 1.05×10‐19 cm2. All the results indicated that Nd‐doped PbClF crystal should be a promising tunable and ultrafast laser material. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
(Benzimidazolin‐2‐ylidene)–AuI–Alkynyl Complexes: Syntheses, Structure, and Photophysical Properties
Authors: Garg Jai Anand , Blacque Olivier , Heier Jakob , Venkatesan Koushik
Published: February 2012

A series of N‐heterocyclic carbene‐based AuI–σ‐acetylide complexes of the type [(Bimz)Au–C≡CR] (Bimz = benzimidazolin‐2‐ylidene; R = aryl, silyl groups) (1a–1l, 2, 3) were prepared from the precursor [(Bimz)AuICl] by an in situ deprotonation of the terminal alkynes. Steady‐state photoluminescence studies revealed that most of these complexes exhibit phosphorescence at room temperature and in 77 K rigidified matrices. Molecular structures were determined by single‐crystal X‐ray diffraction studies for complexes 1a, 1b, 1e, 1f, 1h, 1k, and 1l. Complexes 1f, 1h, and 1l revealed weak unsupported aurophilic interactions. Cyclic voltammetry studies exhibited irreversible behavior with one oxidation peak potential (Ep,a) for most cases in the region 0.7–1.4 V. Experimental and DFT studies suggest that the nature of the emission is predominantly of intraligand character 3IL(π–π*) with a slight perturbation from the metal.
Structural Conformation and Optical and Electrochemical Properties of Imidazolyl‐Substituted Naphthalenediimide and Its HgII, CdII, and CuII Halide Complexes (Eur. J. Inorg. Chem. 8/2012)
Authors: Jiang Jia‐Jian , Yan Cheng , Pan Mei , Wang Zi , Deng Hai‐Ying , He Jian‐Rong , Yang Qing‐Yuan , Fu Lei , Xu Xian‐Fang , Su Cheng‐Yong
Published: March 2012

The cover picture shows that an “end‐core‐end”‐type NDI‐based ligand could take either trans, L or cis conformations, just like the two pincers of a crab can have different relative positions. Its coordination with HgII, CdII, CuII halides leads to the formation of M2L2 metallocycles, 1D zigzag chains or ML metallocycle structures. Details are discussed in the article by M. Pan, C.‐Y. Su et al. on p. 1171 ff.

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α‐Pyrones and Pyranes from the Plant Pathogenic Fungus Pestalotiopsis scirpina
Authors: Li Jian , Wu Xianfu , Ding Gang , Feng Yu , Jiang Xuejun , Guo Liangdong , Che Yongsheng
Published: March 2012

Three new α‐pyrones, scirpyrones A–C (1–3), and four new pyranes, scirpyranes A–D (4–7), were isolated from solid cultures of the plant pathogen Pestalotiopsis scirpina. Their structures were elucidated primarily by NMR experiments. The absolute configurations of C‐7 and C‐2′ in 1, C‐7 in 2, and C‐6 and C‐7 in 3 were deduced on the basis of circular dichroism (CD) data, whereas those of the secondary alcohols in 4–7 were determined by a modification of Mosher's method. Compound 1 is the first described 6‐(5‐oxotetrahydrofuran‐2‐yl)‐2H‐pyran‐2‐one. Compounds 4–6 showed significant cytotoxicity towards MCF‐7 cells.
Time‐resolved measurements of pyrolysis and combustion products of PMMA
Authors: Ghosh Ruby N. , Wichman Indrek S. , Kramer Cory A. , Loloee Reza
Published: February 2012

We studied transient chemical speciation during high‐temperature solid material pyrolysis and combustion in air. Our objective was to develop a database of chemical burn signatures. The material tested was the thermoplastic PMMA. Material samples were heated in an infrared furnace until they pyrolyzed, ignited, and combusted in air. Time‐resolved quantitative measurements of the exhaust species CO2, O2, hydrocarbons, and CO along with exhaust gas temperature were obtained. Two categories of experiments were conducted: (1) pyrolysis tests in which there was no combustion; (2) combustion tests with chemical reaction and heat release.

During heating, the sample underwent numerous processes that appear as diagnostic sequences. In the pyrolysis tests, as the furnace temperature was raised, the CO and hydrocarbon (HC) signals underwent transition from one peak to two peaks. In the combustion tests, spontaneous ignition occurred at higher test temperatures as evidenced by an exothermic reaction reported by the thermocouples, leading to three‐peak CO and HC profiles. The measured O2/CO2 ratio of 1.3 ± 0.1 agreed with stoichiometric methyl‐methacrylate monomer decomposition.

Calculations of the power output using two independent methods supported (1) that combustion was experimentally observed in the furnace, and (2) the accuracy of the combustion gas analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Operating Temperature Dependency on Performance Degradation of Direct Methanol Fuel Cells
Authors: Park J.‐Y. , Kim J.‐H. , Seo Y. , Yu D.‐J. , Cho H. , Bae S. J.
Published: February 2012

The effect of operating temperature on performance degradation of direct methanol fuel cell (DMFCs) is examined to disclose the main parameter of the degradation mechanism and the degradation pattern in the membrane electrode assemblies (MEAs). The DMFC MEA degradation phenomenon is explained through the use of various electrochemical/physicochemical tools, such as electrochemical impedance spectroscopy, electrode polarization, methanol stripping voltametry, field emission‐scanning electron microscopy, X‐ray diffraction, inductively coupled plasma‐atomic emission spectroscopy, and X‐ray photoelectron spectroscopy analysis. The operation of DMFC under high temperature accelerates the degradation process of the DMFC. The higher degradation rate under high temperature DMFC operation is mainly attributed to the formation of membrane pinhole with interfacial delamination and cathode degradation. A high operating temperature may result in more considerable thermal and mechanical stress of the polymeric membrane continuously due to frequent dry–wet cycling mode and substantial uneven distribution of water between the anode and the cathode during a long period of DMFC operation. On the other hand, the electrochemical surface area deterioration by Pt coarsening and ionomers loss is not directly related to the larger DMFC performance decay at high temperature.
Impact of Liquidity on the Futures‐Cash Basis: Evidence from the Indian Market
Authors: Kadapakkam Palani‐Rajan , Kumar Umesh
Published: February 2012

Arbitragers’ activities are constrained by market liquidity. In turn, arbitrage activity may trigger order imbalances adversely affecting liquidity. We examine this issue by analyzing the link between the futures‐cash basis and bid–ask spreads using intraday data on single stock futures (SSFs) contracts on Indian stocks. In contrast to other countries, the SSF market in India is very active due to retail investors’ prior experience with the badla system, a form of forward markets. The analysis reveals two‐way Granger causality between the basis and spreads in both the futures and cash markets. Evidence for spreads Granger‐causing basis is stronger for stocks with higher volume and SSFs that are relatively more active than underlying stocks. © 2012 Wiley Periodicals, Inc. Jrl Fut Mark 33:266–298, 2013