bluuebunny/crossref_metadata_2025 huggingface dataset:
An Inducible Expression System of the Calcium-Activated Potassium Channel 4 to Study the Differential Impact on Embryonic Stem Cells
Authors: Liebau Stefan , Tischendorf Michael , Ansorge Daniel , Linta Leonhard , Stockmann Marianne , Weidgang Clair , Iacovino Michelina , Boeckers Tobias , von Wichert Götz , Kyba Michael , Kleger Alexander
Published: September 2011

Rationale. The family of calcium-activated potassium channels consists of four members with varying biological functions and conductances. Besides membrane potential modulation, SK channels have been found to be involved in cardiac pacemaker cell development from ES cells and morphological shaping of neural stem cells.Objective. Distinct SK channel subtype expression in ES cells might elucidate their precise impact during cardiac development. We chose SK channel subtype 4 as a potential candidate influencing embryonic stem cell differentiation.Methods. We generated a doxycycline inducible mouse ES cell line via targeted homologous recombination of a cassette expressing a bicistronic construct encoding SK4 and a fluorophore from the murine HPRT locus.Conclusion. We characterized the mouse ES cell line iSK4-AcGFP. The cassette is readily expressed under the control of doxycycline, and the overexpression of SK4 led to an increase in cardiac and pacemaker cell differentiation thereby serving as a unique tool to characterize the cell biological variances due to specific SK channel overexpression.
Noetics in pastoral counselling: The making of a semantic differential analysis in pastoral care and counselling
Authors: Louw Dani�l J.
Published: September 2011

Praxis in pastoral care and counselling entails more than merely practice and practicalities (communication skills). Praxis refers to the intentionality within human action and behaviour. Praxis exhibits the realm of intentionality and meaning as displayed within and by human attitudes. It is hypothesised that due to the noetic dimension in human actions, the making of a pastoral diagnosis (a qualitative assessment of the impact of Christian spirituality and the meaning on the system of existential, relational networking) should deal with the realm of significant and purposeful intentionality. The latter is already implied in the phenomenological approach of Edmund Husserl�s eidetic observation or inspection (phenomenological consciousness). In order to incorporate noetics in pastoral care and counselling, a pastoral semantic differential analysis (PSDA) within the making of a pastoral diagnosis was proposed. The PSDA was linked to the need for a qualitative approach regarding the impact of Godimages on religious association and existential life experiences.
$\mathcal D$-bundles and integrable hierarchies
Authors: Ben-Zvi David , Nevins Thomas
Published: September 2011

We study the geometry of

\mathcal D

-
bundles
—locally projective

\mathcal D

-modules—on algebraic curves, and apply them to the study of integrable hierarchies, specifically the multicomponent Kadomtsev-Petviashvili (KP) and spin Calogero-Moser (CM) hierarchies. We show that KP hierarchies have a geometric description as flows on moduli spaces of

\mathcal D

-bundles; in particular, we prove that the local structure of

\mathcal D

-bundles is captured by the full Sato Grassmannian. The rational, trigonometric, and elliptic solutions of KP are therefore captured by

\mathcal D

-bundles on cubic curves

E

, that is, irreducible (smooth, nodal, or cuspidal) curves of arithmetic genus

1

. We develop a Fourier-Mukai transform describing

\mathcal D

-modules on cubic curves

E

in terms of (complexes of) sheaves on a twisted cotangent bundle

{E^{\natural}}

over

E

. We then apply this transform to classify

\mathcal D

-bundles on cubic curves, identifying their moduli spaces with phase spaces of general CM particle systems (realized through the geometry of spectral curves in

{E^{\natural}}

). Moreover, it is immediate from the geometric construction that the flows of the KP and CM hierarchies are thereby identified and that the poles of the KP solutions are identified with the positions of the CM particles. This provides a geometric explanation of a much-explored, puzzling phenomenon of the theory of integrable systems: the poles of meromorphic solutions to KP soliton equations move according to CM particle systems.
On a conjecture by Auerbach
Authors: Fusco Nicola , Pratelli Aldo
Published: September 2011

In 1938 Herman Auerbach published a paper where he showed a deep connection between the solutions of the Ulam problem of floating bodies and a class of sets studied by Zindler, which are the planar sets whose bisecting chords all have the same length. In the same paper he conjectured that among Zindler sets the one with minimal area, as well as with maximal perimeter, is the so-called “Auerbach triangle”. We prove this conjecture.
Enhancing Our Collective Research Acumen by Using an Epidemiological Perspective
Authors: Ciro Carrie
Published: September 2011

Nearly 50 million Americans report some level of disability in activities of daily living or instrumental activities of daily living. Public health officials advocate for a fresh perspective on disability by considering disability through an epidemiological approach. Should occupational therapists perform this research, and what are the benefits for our profession if we do? This article advocates for enhancing our research knowledge base by including an epidemiological perspective in our research design. The benefits to occupational therapy of this research include (1) increased understanding of the extent and nature of occupational performance disability, (2) advancement of the scope and depth of research for prevention and intervention programs, and (3) improved visibility of the profession as informants for public health policy. Suggestions for preparing researchers to perform these studies and students and practitioners to interpret the studies are provided.
Effect of Educational and Supportive Strategies on the Ability of Caregivers of People With Dementia to Maintain Participation in That Role
Authors: Thinnes Andrea , Padilla René
Published: September 2011

A systematic review of evidence of the effectiveness of educational and supportive strategies for enabling caregivers of people with Alzheimer’s disease (AD) or related dementias to maintain participation in that role was conducted as part of the American Occupational Therapy Association’s Evidence-Based Literature Review Project. Forty-three articles met inclusion criteria. Results suggest that interventions that jointly engage people with AD and their caregivers in education and training in the home setting are more successful than strategies that focus solely on people with AD. Greater carryover is noted when education and training are implemented at the time that the caregiver identifies concerns. Interventions should provide caregivers with problem solving, technical skills, support, simple home modification strategies, and referral to community resources. Interventions mediated by technology have a positive effect on the caregiver and are especially important for those who live in rural areas.
Role of fine mode aerosols in modulating cloud properties over industrial locations in north India
Authors: Abish B. , Mohanakumar K.
Published: September 2011

Abstract. The influence of aerosols on cloud properties over North India which includes the Indo-Gangetic Plain has been investigated for the years 2000 to 2010. During the years 2004, 2009 and 2010 there has been an abrupt increase in fine mode aerosol optical depth (AOD) inducing a sharp decline in cloud effective radius (CER) in the month of January. The following monsoon during these years was a failure in the region considered for the study. In the year 2010, a highest AOD value of 0.35 was recorded in the month of January. In accordance with the aerosol indirect effect, this large increase in AOD resulted in a significant reduction in CER. The monsoon season in that year was deficient in the study region even though the rest of the country received above normal rainfall. For the years when CER diminished below 12 microns in the month of May, a delay in the advancement of monsoon towards North India is noted even after a normal or early onset in southern peninsula. Meanwhile, a rapid progression took place when it was 12 microns or above. During non-monsoon months an inverse relationship existed between cloud effective radius and liquid water path and a strong positive association occurred in the monsoon months. Present analysis suggests that the excessive aerosol loading and the associated aerosol indirect effects in the months prior to the monsoon season has an effect on the propagation and onset of the south west monsoon over the region.
Accelerated Testing Methodology for Life Prediction of Polymer Composites
Authors: Nakada Masayuki
Published: September 2011

We have developed an accelerated testing methodology (ATM) to predict the long‐term creep and fatigue life of the polymer matrix composites based on the time‐temperature superposition principle held for the viscoelastic behavior of matrix resin. In this article, the ATM has been explained in detail as the foundation of the long‐term life prediction of polymer matrix composites. Then, the detail procedures for generating the master curves of creep and fatigue strengths based on the ATM are described.
Aging of Organic Matrix Composite Materials
Authors: Colin Xavier , Verdu Jacques
Published: September 2011

This article deals with aging mechanisms and kinetics in organic matrix composites, focusing on water‐polymer (humid aging) and oxygen‐polymer (thermo‐oxidative aging) interactions.

The first section is devoted to problems common to all kinds of chemical aging, with emphasis on specific aspects of composite materials, for instance, role of interphase/interface in aging processes or anisotropy of water or oxygen diffusion in fiber‐reinforced materials. The effects of mechanical loading on diffusion kinetics and the diffusion‐reaction coupling are briefly evoked.

The second section deals with humid aging. It is important to distinguish physical processes linked to plasticization and swelling of the polymer matrix by water and chemical (hydrolytic) aging, an ionic step‐by‐step reaction, which affects only polycondensates, especially polyesters. Hydrolysis induces random chain scission responsible for embrittlement and sometimes osmotic cracking responsible for blistering of the glass fiber‐polyester composites.

The third section concerns thermo‐oxidative aging that results from a branched radical chain reaction. This kind of aging occurs when the material is exposed to high temperatures during its processing or in its use conditions, which is the case of many aerospace applications. The basics of nonempirical kinetic modeling are presented. The last section deals with the consequences of thermo‐oxidation on the thermomechanical properties including glass transition temperature, elastic properties, and fracture properties.
Angle Ply Laminates
Authors: Piggott Michael R.
Published: September 2011

Angle ply laminates have surprisingly good properties. They are much stronger and tougher than the pseudo‐isotopic laminates used for aircraft structures. Also, they do not have problems with weak transverse layers. A design protocol for these laminates is presented for manufacture, which is readily carried out using fiber placement.
Biodegradable Starch‐Based Nano‐Composites
Authors: Xie Fengwei
Published: September 2011

Compared to normal starch‐based materials, starch nanocomposites have attracted much interest in the recent years due to the drastic improvements in the mechanical properties, thermal stability, flame retardant properties, gas barrier properties, and so on. There are three main types of nanofillers that have been frequently used to reinforce starch matrix, that is, starch nanocrystals/nanoparticles, cellulose nanowhiskers/nanofibers, and layered nanoclays. This article discusses these three types of biodegradable starch‐based nanocomposite systems in terms of their formulation‐processing‐structure‐properties relationships in detail. Layered nanoclays have been the most popular choice for preparing starch‐based nanocomposites. Nanoclay surface chemistry, starch type (including amylose content) and chemical modification, and starch‐plasticizer‐nanofiller interactions during processing have to be considered in order to increase the intercalation/exfoliation of nanoclay in the starch matrix. It is revealed that the hydrophilicity difference between nanoclay and starch plays a dominant role in the nanostructural evolution. In addition, starch/biodegradable polymer/nanoclay multiphase nanocomposite system has been a popular choice for further improved properties. The renewability and biodegradability of starch‐based nanocomposite materials justify its wide use as truly sustainable plastics.
Bonded Composite Patch Repair of Metallic Aircraft Structures
Authors: Baker Alan
Published: September 2011

Efficient, cost‐effective repairs to cracks or corrosion in metallic airframe structures can be made using fiber composite patches—such as carbon/epoxy or boron/epoxy, adhesively bonded to the defective region. A brief overview of this technology is provided in this article, addressing most significant issues including design, choice of materials, repair implementation, and, for repairs to primary structure, certification. Two application case histories are briefly described: (i) to the wing skin of a USAF F16 and (ii) to the wing skin of an RAAF F‐111.
Composites Based on Nanocomposite Matrices
Authors: Monti Marco , Natali Maurizio , Petrucci Roberto , Puglia Debora , Terenzi Andrea , Valentini Luca , Kenny José Maria
Published: September 2011

The incorporation of nanofillers into the polymer composites induces new properties and functions based on synergetic effects. This review provides a variety of industrial scalable processes and techniques such as solution mixing,in situpolymerization, and covalent grafting for fabricating such nanostructured‐based composites. The developments in the design of nanostructured‐based systems will continue to emerge as we venture into the 2D domain of carbon nanostructures in future.
Ceramic Matrix Composites: Reaction Bonded
Authors: Ortona Alberto
Published: September 2011

Ceramic matrix composite (CMC) materials offer unique design possibilities for their superior thermo‐mechanical properties. There are several manufacturing techniques to produce CMC. Reaction bonding is illustrated in this paragraph. Reaction‐bonded CMCs with the larger amount of publications and industrial applications are silicon carbides (RBSiC) and silicon nitrides (RBSN) composites. After years of research work, mostly in the aeronautical and aerospace sectors, there are several applications of these composite materials. As a sort of follow‐up of many years of basic and industrial research, RBSiC has found its way to industrial markets thanks to the friction components. Nowadays RBSiC composites are a standard in high performance braking systems for racing and sport cars. Further work is ongoing trying to protect these materials against active oxidation and to increase their upper temperature working limit by using, during melt infiltration, silicon alloyed with other metals. RBSN presents outstanding thermo‐mechanical properties but, for their applications in oxidative environments, they need to be coated with environmental barriers.
Composite Fiber Reinforcement Forming
Authors: Boisse Philippe
Published: September 2011

Double‐curved composite parts can be obtained by the forming of an initially flat fibrous reinforcement. Because the preform is made of fibers, the deformation mechanisms during the forming are specific. The objectives of analyses and simulations of the forming process are both to determine the conditions that will make the forming possible without defect and to know the position of the fibers after forming. Textile reinforcement can be modeled at different scales. In this article, hypoelastic and a hyperelastic approaches at the macroscopic scale are presented. Then a mesoscopic approach based on a simplified description of the woven unit cell is used for forming simulations. Finally, the semi‐discrete approach that can be seen as intermediate between continuous and mesoscopic approaches is presented.
Composite Materials for Aeronautic Application
Authors: Iannone Michele
Published: September 2011

The most important aspects of composite usage in aircraft structures are discussed.

Different kinds of fiber reinforcement and matrix are compared. A large part of the article is focused on carbon epoxy prepregs, that is, preimpregnated materials having a continuous fiber reinforcement and an epoxy resin matrix.

The major issues of prepreg processing are outlined, with a description of the different phases of the process. Most of the discussion is focused on the lay‐up plus autoclave processing, which is the most frequent processing approach.

A short comparison between laminate and sandwich structures is also reported.

“No prepreg” techniques are also listed, such as resin transfer molding and resin infusion molding.

Elements are reported of composite structural properties, including the effect of temperature, aging, and damage tolerance. Some additional information on aging and accelerated aging techniques is also included. The behavior of composites exposed to fire, as well as functional properties (conductivity, acoustic damping, etc.) are also shortly listed.

The advantages of lighter structures are considered taking in account also the cost issues, and some specific applications of composites in the aircraft structures are described, stressing the very fast increase of these materials in the aeronautic structural applications.

Finally, the future trends in the technological improvement of composite material, processes, and structures for aeronautical application are shortly outlined.
Compression Properties of Fibers and Polymer Composites
Authors: Piggott Michael R.
Published: September 2011

The factors controlling the compressive strength and modulus are reviewed. These are the initial straightness of the fibers in the laminate, the compressive strength of the fibers, and the matrix compression properties (yield strength, modulus, etc.). The most recent and reliable compression testing methods are described and the sources of compressive strength and stiffness are discussed. The compressive strengths and stiffnesses of carbon, glass, and aramid laminates are then summarized.
Furan Composites
Authors: Uygun Gok Aysegul
Published: September 2011

This article outlines the major studies on the polyfuran composites published over the past decade. The properties of the polyfuran composites synthesized chemically were modified in the presence of different materials such as conducting polymers, metal oxide, acetylene black, and zeolites. The results were listed, discussed, and compared. It was hoped that this article including relevant data might enhance knowledge about polyfuran composites and lead to new works.
Graphene Composites
Authors: Young Robert J. , Kinloch Ian A.
Published: September 2011

The preparation and structure of different forms of graphene are first of all reviewed. Methods of preparation of graphene such as by exfoliation and chemical vapor deposition are described, and the material produced is shown to be quite different from the graphene oxide formed during the chemical oxidation of graphite. The basic structure and mechanical properties of both graphene and graphene oxide are described, and it is shown that they can both have high levels of stiffness and strength. It is demonstrated how Raman spectroscopy can be used to characterize the different forms of graphene and also follow the deformation of a graphene monolayer in a model composite. It is shown that continuum mechanics can be employed to follow the stress transfer to the graphene monolayer even though it is only one atom thick. Finally, the preparation of bulk nanocomposites based on graphene and graphene oxide is described and the properties of these materials are discussed. It is shown that good reinforcement is only found at relatively low levels of loading of the reinforcement and that, due probably to difficulties with dispersion, challenges still remain in obtaining good mechanical properties for high volume fractions of reinforcement.
Laminated Glass
Authors: Zang M. Y. , Chen S. H.
Published: September 2011

Laminated glass has been developing with a history of over 100 years. Then various kinds of glass such as annealed glass, float glass, tempered glass, absorbing glass and films such as PVB, SGP, EVA are described. With the new trend of environmental protection and energy saving, large amounts of new types of laminated glass are emerging when different kinds of glass and films are put together. There are two main methods of producing laminated glass, namely, the dry method and the wet method. And then, three impact tests and two main simulation analysis of laminated glass are introduced. The three impact tests are the drop weight test, Charpy impact test, and Izod impact test respectively. While the two main simulation analysis are finite element method and discrete element method.
Manufacturing of Thermoplastic Fiber‐Reinforced Polymer Composites
Authors: Mitschang Peter
Published: September 2011

This article presents a comprehensive introductory overview of thermoplastic composites manufacturing. From classical to reactive thermoplastics; fibers and textile structures to semifinished products; modern‐day manufacturing processes and post‐processing techniques to the manufacturing process chain associated with these types of materials. The most important topics in the field of thermoplastic fiber‐reinforced polymer composites manufacturing have been collated and covered in a clear and concise manner providing the most important references to the main authorities in each subtopic giving the reader the most important sources for further information.
Mechanical Properties of Molecular Composites
Authors: Hara Masanori
Published: September 2011

Various methods have been developed to make molecular composites, including coagulation,in situpolymerization of a matrix polymer, and the addition of a rigid chain to a flexible chain in block copolymers. However, many systems eventually phase separate due to inherent immiscibility of component polymers on heating; thus, they are not appropriate for melt processing, usually necessary for large‐scale production. In addition, most of the mechanical properties reported are tensile properties of fiber and film specimens. Bulk sample data are rare. This is again due to a lack of thermal consolidation without causing phase separation in many molecular composites. One promising approach to circumventing this problem is introduction of strong intermolecular interactions, such as ion–ion and ion–dipole interactions. In this article, after citing some results on mechanical properties of molecular composites based on nonionic rod‐like molecules, mechanical properties of molecular composites made via ionic interactions (ion–dipole interactions) are described.
Polyurethane Precursors
Authors: Tanzi Maria Cristina
Published: September 2011

This article intends to provide a basic knowledge of polyurethanes (PUs) and their typologies, with particular reference to starting materials, both from a scientific and a commercial point of view. The possible types of PUs are described in short, together with their methods of production. Safety, ecological items, and recycling are considered as well. As a final point, the advantages of the use of PUs in composites production are highlighted, with an indication of the reinforced PU production processes.
Printed Circuit Board Laminates
Authors: Sood Bhanu , Pecht Michael
Published: September 2011

Printed circuit boards (PCBs) are the interconnection medium on which electronic components are assembled to create electronic systems. The primary functions of PCBs are to contain the wiring required to interconnect components electrically, to act as the primary structure to support all components in a circuit, and, in many instances, to conduct away heat generated by the components. With the constant drive for miniaturization, increased functionality, and higher speeds, an increasing number of functions must be accommodated on a PCB within the same size or even in an overall smaller size. The purpose of this article is to describe the typical material makeup, techniques, and manufacturing processes used in PCB fabrication. The article then discusses the common PCB failure modes and associated causes with a focus on process control and inspection techniques that can be used during fabrication. An overview of cost structure and overall impact of introduction of newer processing conditions is also discussed.
Testing: Mechanical Characterization
Authors: Herakovich Carl T.
Published: September 2011

Test methods for mechanical testing of fibrous composite materials subjected to tension, shear, and compression are presented. Material response into the nonlinear range and effective elastic constants are presented for selected composites.
The wisdom of webs a‐weaving: Adult education and the paradoxes of complexity in changing times
Authors: Tisdell Elizabeth J.
Published: September 2011

This chapter introduces the volume and provides an overview of the literature on the nature of wisdom and the wisdom of nature as weaving webs of connection and embracing paradox that can offer insight to current trends in adult education.
Strategien und Taktiken für die metallgesteuerte Synthese von Rotaxanen, Knoten, Catenanen und Verschlingungen höherer Ordnung
Authors: Beves Jonathon E. , Blight Barry A. , Campbell Christopher J. , Leigh David A. , McBurney Roy T.
Published: September 2011

Mehr als ein Vierteljahrhundert nach der ersten Metalltemplatsynthese eines [2]Catenans in Straßburg existiert nun eine Fülle an Strategien zum Aufbau mechanisch verbundener und verflochtener Strukturen auf molekularer Ebene. Catenane, Rotaxane, Knoten und Borromäische Ringe sind alle erfolgreich über Methoden zugänglich, in denen Metallionen eine Schlüsselrolle spielen. Ursprünglich wurden Metallionen ausschließlich aufgrund ihrer Koordinationschemie verwendet, indem sie entweder die einzelnen Bausteine auf eine Weise anordneten, die durch anschließende Reaktionen die Erzeugung der verschlungenen Produkte ermöglichte, oder indem sie selbst als wesentlicher Bestandteil der Ringe oder als “Stopper” dienten. Vor kurzem wurde die Rolle des Metalls auch auf die Katalyse ausgedehnt: Die Metallionen ordnen die Bausteine nicht nur zu einer verflochtenen oder eingefädelten Struktur an, sondern fördern auch aktiv die Strukturbildung durch kovalenten Einfangen. Dieser Aufsatz fasst die Strategien zur Bildung mechanisch verbundener Molekülstrukturen mit Metallionen zusammen und diskutiert die Taktiken, die zum Aufbau von Überkreuzungen, zur Maximierung der Ausbeuten verschlungener und nichtverschlungener Produkte und zur Bildung eingefädelter oder verflochtener Intermediate durch kovalenten Einfang zur Verfügung stehen.
Funktionelle Gemischtmetall‐organische Gerüste mit Metalloliganden
Authors: Das Madhab C. , Xiang Shengchang , Zhang Zhangjing , Chen Banglin
Published: September 2011

Die Immobilisierung funktioneller Zentren innerhalb von Metall‐organischen Gerüsten (MOFs) ist für ihre Fähigkeit zur Erkennung kleiner Moleküle und somit für ihre funktionellen Eigenschaften von großer Bedeutung. Das Metalloligandverfahren ermöglicht es uns, eine Vielzahl unterschiedlicher funktioneller Zentren wie offene, katalytisch aktive und photoaktive Metallzentren, chirale Porenumgebungen und Poren abstimmbarer Größe/Krümmung in Gemischtmetall‐organischen Gerüsten (M′MOFs) zielgerichtet zu immobilisieren. In diesem Kurzaufsatz richten wir die Aufmerksamkeit auf einige wichtige funktionelle M′MOFs mit Metalloliganden für die Gasspeicherung und ‐trennung, die enantioselektive Trennung, die heterogene asymmetrische Katalyse und die Sensorik sowie als photoaktive, nanoskalige Materialien für die Wirkstoff‐Freisetzung und biomedizinische Bildgebung.
Porosity formation by biaxial stretching in polyolefin films filled with calcium carbonate particles
Authors: Qaiss A. , Saidi H. , Fassi‐Fehri O. , Bousmina M.
Published: September 2011

Porous polymer films were generated by biaxial stretching of polypropylene (PP) and high‐density polyethylene (HDPE) filled with various amounts of calcium carbonate particles. The porosity of the films was measured by mercury porosimetry, and the obtained results were related to the processing conditions and to the morphology development during the biaxial stretching. The results showed that increasing the calcium carbonate (CaCO3) concentration and the draw ratio resulted in porosity increase for PP‐based composite films and in a decreased porosity in HDPE‐based composite films. Such peculiar behavior was connected to interfacial specific interactions between the matrix and the dispersed particles as well as to the crystallinity of the films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Characterization of a chelating resin functionalized via azo spacer and its analytical applicability for the determination of trace metal ions in real matrices
Authors: Islam Aminul , Ahmad Akil , Laskar Mohammad Asaduddin
Published: September 2011

A selective flame atomic absorption spectrometric method has been developed for the determination of trace amount of metal ions after preconcentration on salicylic acid (SA) loaded Amberlite XAD‐4 resin (AXAD‐4) at suitable pH. The chelating resin AXAD‐4‐SA was characterized based on FTIR, thermal and chemical stability, and hydrogen ion capacity. The sorption capacity was found to be 245.0, 156.2, 155.0, 145.0, 125.0, 122.5, and 70 μmol g−1 for Cu(II), Cr(III), Zn(II), Cd(II), Mn(II), Ni(II), and Co(II), respectively with t1/2 <15 min. All the metals could be eluted by 5 mL of 4 mol L−1 HCl/HNO3 resulting in high preconcentration factor of 200–360 up to a low preconcentration limit of 5.5–10 μg L−1. The accuracy and precision of the developed method was checked by analyzing standard reference materials. The experimental values were not statistically significant from the certified values with <5% RSD. The detection limits were found to be 0.42, 0.57, 0.63, 0.77, 0.94, 0.96, and 1.41 μg L−1, respectively. The analytical utility of the AXAD‐4‐SA for preconcentration and determination of metal ions was explored by analyzing river, canal, sewage, and tap water by direct as well as standard addition method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Systematic review of exercise training or percutaneous transluminal angioplasty for intermittent claudication
Authors: Frans F A , Bipat S , Reekers J A , Legemate D A , Koelemay M J W
Published: September 2011

Background

The aim was to summarize the results of all randomized clinical trials (RCTs) comparing percutaneous transluminal angioplasty (PTA) with (supervised) exercise therapy ((S)ET) in patients with intermittent claudication (IC) to obtain the best estimates of their relative effectiveness.

Methods

A systematic review was performed of relevant RCTs identified from the MEDLINE, Embase and Cochrane Library databases. Eligible RCTs compared PTA with (S)ET, included patients with IC due to suspected or known aortoiliac and/or femoropopliteal artery disease, and compared their effectiveness in terms of functional outcome and/or quality of life (QoL).

Results

Eleven of 258 articles identified (reporting data on eight randomized clinical trials) met the inclusion criteria. One trial included patients with isolated aortoiliac artery obstruction, three trials studied those with femoropopliteal artery obstruction and five included those with combined lesions. Two trials compared PTA with advice on ET, four PTA with SET, two PTA plus SET with SET and two PTA plus SET with PTA. Although the endpoints in most trials comprised walking distances and QoL, pooling of data was impossible owing to heterogeneity. Generally, the effectiveness of PTA and (S)ET was equivalent, although PTA plus (S)ET improved walking distance and some domains of QoL scales compared with (S)ET or PTA alone.

Conclusion

As IC is a common healthcare problem, defining the optimal treatment strategy is important. A combination of PTA and exercise (SET or ET advice) may be superior to exercise or PTA alone, but this needs to be confirmed. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
Neuroprotective effects of Tacrolimus (FK‐506) and Cyclosporin (CsA) in oxidative injury
Authors: Yousuf Seema , Atif Fahim , Kesherwani Varun , Agrawal Sandeep Kumar
Published: September 2011

The detrimental effects of hypoxic damage to central nervous system lead to energy depletion, free radical formation, lipid peroxidation (LPO), and increased calcium. We hypothesized that in vitro tacrolimus (FK‐506) and cyclosporine A (CsA) could be protective against hypoxic damage in spinal cord. Dorsal columns were isolated from the spinal cord of adult rats and injured by exposure to hypoxic condition for 1 h, and treated with FK‐506 (0.1 μM) and CsA (0.1 μM). After injury, reperfusion was carried out for 2 h. Tissues were collected, processed for biochemical assays, and 2,3,5‐triphenyltetrazolium chloride (TTC) staining. Spinal cord hypoxia caused a significant decrease (P < 0.001) in mitochondrial ATP (30.64%) and tissue reduced glutathione (GSH) (60.14%) content. Conversely, a significant increase (P < 0.001) in tissue LPO level (57.77%) and myeloperoxidase (MPO) activity (461.24%) was observed in hypoxic group. Mitochondrial swelling was also significantly increased in hypoxic group (90.0%). Treatment with either FK‐506 or CsA showed that significant neuroprotective effects (P < 0.05–0.01) were measured in various parameters in hypoxic groups. FK‐506 and CsA treatment showed increase in ATP by 11.19% and 16.14% while GSH content increased by 66.46% and 77.32%, respectively. Conversely, LPO content decreased by 18.97% and 24.06% and MPO level by 42.86% and 18.66% after FK‐506 and CsA treatment. Calcium uptake was also decreased in mitochondria as exhibited by the increase in absorbance by 11.19% after FK‐506 treatment. TTC staining also showed increased viability after FK‐506 and CsA treatment. In conclusion, present study demonstrates the neuroprotective effect of FK‐506 and CsA treatment against spinal cord hypoxia induced damage is mediated via their antioxidant actions.
Metabolically Stable Cellular Adhesion to Inert Surfaces
Authors: Meldal Morten , Wu Boqian , Diness Frederik , Michael Roice , Hagel Grith
Published: September 2011

The structure of D‐amino acid hexapeptides that promote cellular adhesion was determined by screening D‐amino acid hexapeptide libraries synthesized on otherwise inert beaded PEGA resin. These new adhesion molecules provide a completely stable cellular environment and facilitate the maintenance of a monolayer of cells on beads for extended periods. The presence of the peptides promotes spreading of the cells on the bead surface. Not surprisingly, the molecules contained a significant number of arginines and/or lysines. However, the exact structure of each peptide is quite important for the degree of adhesion observed, and a motif with three or four basic amino acids spaced within amino acids of intermediate polarity clearly prevailed, for example, k‐l/r‐h‐r‐i/v‐r‐a; this maintains a polar/hydrophobic balance.
A Rational Design for the Directed Helicity Change of Polyacetylene Using Dynamic Rotaxane Mobility by Means of Through‐Space Chirality Transfer
Authors: Ishiwari Fumitaka , Fukasawa Kei‐ichiro , Sato Takashi , Nakazono Kazuko , Koyama Yasuhito , Takata Toshikazu
Published: September 2011

Directed helicity control of a polyacetylene dynamic helix was achieved by hybridization with a rotaxane skeleton placed on the side chain. Rotaxane‐tethering phenylacetylene monomers were synthesized in good yields by the ester end‐capping of pseudorotaxanes that consisted of optically active crown ethers and sec‐ammonium salts with an ethynyl benzoic acid. The monomers were polymerized with [{RhCl(nbd)}2] (nbd=norbornadiene) to give the corresponding polyacetylenes in high yields. Polymers with optically active wheel components that are far from the main chain show no Cotton effect, thereby indicating the formation of racemic helices. Our proposal that N‐acylative neutralization of the sec‐ammonium moieties of the side‐chain rotaxane moieties enables asymmetric induction of a one‐handed helix as the wheel components approach the main chain is strongly supported by observation of the Cotton effect around the main‐chain absorption region. A polyacetylene with a side‐chain rotaxane that has a shorter axle component shows a Cotton effect despite the ammonium structure of the side‐chain rotaxane moiety, thereby suggesting the importance of proximity between the wheel and the main chain for the formation of a one‐handed helix. Through‐space chirality induction in the present systems proved to be as powerful as through‐bond chirality induction for formation of a one‐handed helix, as demonstrated in an experiment using non‐rotaxane‐based polyacetylene that had an optically active binaphthyl group. The present protocol for controlling the helical structure of polyacetylene therefore provides the basis for the rational design of one‐handed helical polyacetylenes.
4‐Substituted Thioquinolines and Thiazoloquinolines: Potent, Selective, and Tween‐80 in vitro Dependent Families of Antitubercular Agents with Moderate in vivo Activity
Authors: Escribano Jaime , Rivero‐Hernández Cristina , Rivera Hilda , Barros David , Castro‐Pichel Julia , Pérez‐Herrán Esther , Mendoza‐Losana Alfonso , Angulo‐Barturen Íñigo , Ferrer‐Bazaga Santiago , Jiménez‐Navarro Elena , Ballell Lluís
Published: September 2011

Two new families of closely related selective, non‐cytotoxic, and potent antitubercular agents were discovered: thioquinolines and thiazoloquinolines. The compounds were found to possess potent antitubercular properties in vitro, an activity that is dependent on experimental conditions of MIC determination (resazurin test and the presence or absence of Tween‐80). To clarify the therapeutic potential of these compound families, a medicinal chemistry effort was undertaken to generate a lead‐like structure that would enable murine efficacy studies and help elucidate the in vivo implications of the in vitro observations. Although the final compounds showed only limited levels of systemic exposure in mice, modest levels of efficacy in vivo at nontoxic doses were observed.
Tightness of the recentered maximum of the two‐dimensional discrete Gaussian free field
Authors: Bramson Maury , Zeitouni Ofer
Published: September 2011

We consider the maximum of the discrete two‐dimensional Gaussian free field (GFF) in a box and prove that its maximum, centered at its mean, is tight, settling a longstanding conjecture. The proof combines a recent observation by Bolthausen, Deuschel, and Zeitouni with elements from Bramson's results on branching Brownian motion and comparison theorems for Gaussian fields. An essential part of the argument is the precise evaluation, up to an error of order 1, of the expected value of the maximum of the GFF in a box. Related Gaussian fields, such as the GFF on a two‐dimensional torus, are also discussed. © 2011 Wiley Periodicals, Inc.
The Effect of Backbone Constraints: The Case of Water Oxidation by the Oxygen‐Evolving Complex in PSII
Authors: Siegbahn Per E. M.
Published: September 2011

The procedure for fixing atoms of amino acid residues in cluster model calculations on enzymes is reviewed. Examples from recent calculations on photosystem II (PSII) and Mo,Cu‐dependent CO dehydrogenase are given. In this context, the cluster model work on finding a mechanism for OO bond formation and a structure of the oxygen‐evolving complex in PSII is also reviewed. In that work, fixing certain atoms played an important role. The main part of the present study concerns the mechanism in PSII using models based on the new high‐resolution (1.9 Å) X‐ray structure, which is compared to that using the old, theoretically suggested, structure. It is concluded that the mechanism remains the same, with a similar barrier height. Finally, a connection between the OEC structure and Mn,Ca‐containing minerals is also briefly discussed.
Flux Bridgman growth and the influence of annealing temperatures on PL properties of ZnO single crystals
Authors: Xu Jiayue , He Qingbo , Shen Hui , Jin Min , Zhang Yan , Li Xinhua
Published: September 2011

Transparent ZnO crystals were obtained by the flux Bridgman method from high temperature solution of 22 mol% ZnO‐78 mol% PbF2 system. The influence of annealing temperatures on the photoluminescence (PL) of ZnO crystal was investigated. An ultraviolet emission peak at about 379 nm was observed in PL spectra and the peak position has a weak blueshift for annealed samples. A green band centered at 523 nm appeared in the annealed samples and its intensity enhanced with the increase of annealing temperatures, while the intensity of the ultraviolet peak decreased considerably. However, the ultraviolet emission peak became the strongest after annealing at 1000 °C. This phenomenon was considered to be associated with oxygen vacancy and F‐ impurities induced by the PbF2 flux. The results show that high temperature annealing in air seems helpful for improving the PL properties of ZnO crystal. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conspecific brood parasitism in the tropics: an experimental investigation of host responses in common moorhens and American purple gallinules
Authors: McRae Susan B.
Published: September 2011

Species occupying a broad latitudinal range may show greater phenotypic plasticity in behavior than species with smaller ranges or more specific habitat requirements. This study investigates for the first time the occurrence of conspecific brood parasitism (CBP) in sympatric tropical populations of the common moorhen (Gallinula chloropus pauxillaBangs) and the American purple gallinule (Porphyrula martinicaL.). CBP occurred in at least 20% (N= 76) of common moorhen nests on the Rio Chagres in Panama. Half (N= 20) of the parasitic eggs were accepted, but 10 were destroyed or ejected from host nests. Introductions of experimental eggs into nests revealed hosts were more likely to accept parasitism later in the host's laying period and during incubation, consistent with expectation of an adaptive response. CBP was not detected in a small sympatric population of American purple gallinules. Members of this population did not eject experimental eggs, suggesting a lack of experience with costly CBP. Contrasting ecological factors help explain why these two species of rail (Family Rallidae) differ in regard to CBP. Purple gallinule territories were sparse, owing to the distribution of preferred habitat. Moorhens flocked outside of the breeding season. They nested more synchronously, at higher densities, and primarily in ephemeral floating vegetation. Further, moorhens suffered a rate of nest loss nearly double that of American purple gallinules, and this increased over the course of the breeding season. Moorhen clutches were larger on average, and more variable in size than those of purple gallinules. Reproductive effort and rate (seasonality) constitute important life history differences between these species that may constrain the evolution of reproductive tactics. Comparing these sympatric populations, and others differing in life‐history traits and ecological constraints, highlights the role of risk management in the evolution of CBP.
Strong Charge‐Transfer Chromophores from [2+2] Cycloadditions of TCNE and TCNQ to Peripheral Donor‐Substituted Alkynes
Authors: Chen Songhua , Li Yongjun , Liu Chao , Yang Wenlong , Li Yuliang
Published: September 2011

Peripheral donor‐substituted N,N‐dimethyl‐4‐[(7‐nitrobenzo[c][1,2,5]thiadiazol‐4‐yl)ethynyl]aniline (1a), 4‐(benzo[c][1,2,5]thiadiazol‐4‐ylethynyl)‐N,N‐dimethylaniline (1b), and 4,4′‐{benzo[c][1,2,5]thiadiazole‐4,7‐diylbis(ethyne‐2,1‐diyl)}bis(N,N‐dimethylaniline) (2) were prepared by Sonogashira cross‐coupling reactions. Compounds 1a, 1b, and 2 subsequently reacted with tetracyanoethylene (TCNE) or 7,7,8,8‐tetracyanoquinodimethane (TCNQ) to afford the charge‐transfer chromophores 3–8. X‐ray crystallographic analysis revealed the nonplanarity of these donor–acceptor (D–A) chromophores. Cyclic voltammetry (CV) exhibited a multistep reduction wave. UV/Vis spectra and theoretical calculations identified efficient intramolecular charge‐transfer interactions. Moreover, scanning electron microscopy (SEM) showed the morphology transition and reconstruction process of 5 from 0D hollow nanospheres to 1D tubular microstructures.
A simple and rapid pre‐confirmation method to distinguish endogenous human haemoglobin from synthetic haemoglobin‐based oxygen carriers in doping control
Authors: Donati Francesco , Mazzarino Monica , de la Torre Xavier , Botrè Francesco , Islam Nazia , Cowan David
Published: September 2011

A specific, sensitive and rapid analytical procedure based on capillary electrophoresis with UV/Vis detection at 405 and 415 nm was developed and validated to detect human haemoglobin and haemoglobin‐based oxygen carriers (Hemopure®, Oxyglobin® and Polyheme®) in blood samples collected for doping control. The electrophoretic separation, based on capillary dynamic coating, was achieved in less than 10 min. The effects of capillary temperature, injection conditions and initial ramping were investigated. The optimum separation voltage was 25 kV with a capillary temperature of 20°C, initial ramping of 1 kV/s and an injection pressure of 0.5 psi for 10 s. The removal of haptoglobin using anti‐human haptoglobin antibody prior to the analysis was mandatory to increase the specificity of the analysis. Sufficient resolution between endogenous haemoglobin variants and the three haemoglobin‐based oxygen carriers here investigated was obtained, thus allowing discrimination between a normal haemolysed sample and a sample in which Oxyglobin®, Hemopure® or Polyheme® is present. Good repeatability of migration times (CV% less than 1), peak resolution and adequate sensitivity (limit of detection: 2.5 mg/mL) was obtained.
Single‐phase transformer modeling for inrush ‎currents simulation using differential evolution
Authors: Ketabi Abbas , Naseh Mojtaba
Published: September 2011

Accurate modeling of transformer saturation characteristics is essential for analyzing inrush currents and ‎harmonic overvoltages. This paper outlines a straightforward method for correct estimation of the transformer's inrush current where the residual flux effect is considered. The Ι–Λ nonlinear characteristic of transformer core is estimated by the sum of ‎two exponential functions. The differential evolution optimization method is used to identify the parameters of ‎the iron core ‎model including the current flux nonlinear function and the core loss resistance. The ‎objective function to be minimized is the root mean square difference between the measured and calculated ‎inrush currents. The experimental iron characteristic is obtained from the secondary winding voltage ‎and primary winding current waveforms produced during transformer energization. The performance and accuracy of the proposed method have been verified by a close ‎agreement between simulation and measured inrush waveforms for a single‐phase transformer. Copyright © 2011 John Wiley & Sons, Ltd.