bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupled magnetic resonator optical waveguides
Authors: Liu Hui , Zhu Shining
Published: March 2013

Optical resonators are important devices that control the properties of light and manipulate light–matter interaction. Various optical resonators are designed and fabricated using different techniques. For example, in coupled resonator optical waveguides, light energy is transported to other resonators through near‐field coupling. In recent years, magnetic optical resonators based on LC resonance have been realized in several metallic microstructures. Such devices possess stronger local resonance and lower radiation loss compared with electric optical resonators. This study provides an overall introduction on the latest progress in coupled magnetic resonator optical waveguide (CMROW). Various waveguides composed of different magnetic resonators are presented and Lagrangian formalism is used to describe the CMROW. Moreover, several interesting properties of CMROWs, such as abnormal dispersions and slow‐light effects, are discussed and CMROW applications in nonlinear and quantum optics are shown. Future novel nanophotonic devices can be developed using CMROWs.
Treatment of hypertrophic scars using laser and laser assisted corticosteroid delivery
Authors: Waibel Jill S. , Wulkan Adam J. , Shumaker Peter R.
Published: March 2013

Background and Objectives

Hypertrophic scars and contractures are common following various types of trauma and procedures despite skilled surgical and wound care. Following ample time for healing and scar maturation, many millions of patients are burdened with persistent symptoms and functional impairments. Cutaneous scars can be complex and thus the approach to therapy is often multimodal. Intralesional corticosteroids have long been a staple in the treatment of hypertrophic and restrictive scars. Recent advances in laser technology and applications now provide additional options for improvements in function, symptoms, and cosmesis. Fractional ablative lasers create zones of ablation at variable depths of the skin with the subsequent induction of a wound healing and collagen remodeling response. Recent reports suggest these ablative zones may also be used in the immediate post‐operative period to enhance delivery of drugs and other substances. We present a case series evaluating the efficacy of a novel combination therapy that incorporates the use of an ablative fractional laser with topically applied triamcinolone acetonide suspension in the immediate post‐operative period.

Methods

This is a prospective case series including 15 consecutive subjects with hypertrophic scars resulting from burns, surgery or traumatic injuries. Subjects were treated according to typical institutional protocol with three to five treatment sessions at 2‐ to 3‐month intervals consisting of fractional ablative laser treatment and immediate post‐operative topical application of triamcinolone acetonide suspension at a concentration of 10 or 20 mg/ml. Three blinded observers evaluated photographs taken at baseline and six months after the final treatment session. Scores were assigned using a modified Manchester quartile score to evaluate enhancements in dyschromia, hypertrophy, texture, and overall improvement.

Limitations

Small sample size and lack of a control arm.

Results

Combination same session laser therapy and immediate post‐operative corticosteroid delivery resulted in average overall improvement of 2.73/3.0. Dyschromia showed the least amount of improvement while texture showed the most improvement.

Conclusion

Combination same‐session therapy with ablative fractional laser‐assisted delivery of triamcinolone acetonide potentially offers an efficient, safe and effective combination therapy for challenging hypertrophic and restrictive cutaneous scars. Lasers Surg. Med. 45: 135–140, 2013. © 2013 Wiley Periodicals, Inc.
Arraying Cell Cultures Using PEG‐DMA Micromolding in Standard Culture Dishes
Authors: Marel Anna‐Kristina , Rappl Susanne , Piera Alberola Alicia , Rädler Joachim Oskar
Published: March 2013

A robust and effortless procedure is presented, which allows for the microstructuring of standard cell culture dishes. Cell adhesion and proliferation are controlled by three‐dimensional poly(ethylene glycol)‐dimethacrylate (PEG‐DMA) microstructures. The spacing between microwells can be extended to millimeter size in order to enable the combination with robotic workstations. Cell arrays of microcolonies can be studied under boundary‐free growth conditions by lift‐off of the PEG‐DMA layer in which the growth rate is accessible via the evolution of patch areas. Alternatively, PEG‐DMA stencils can be used as templates for plasma‐induced patterning.

magnified image
Design of New Reaction Fields for Spherical Polypyrrole Particle Synthesis
Authors: Kobayashi Daisuke , Endo Yuko , Sakamoto Tadaaki , Takahashi Tomoki , Matsumoto Hideyuki , Kuroda Chiaki , Otake Katsuto , Shono Atsushi
Published: March 2013

Summary: Polypyrrole conducting polymers have been investigated widely for various applications because of their thermal and environmental stability and good electrical conductivity. Using chemical oxidative polymerization for the synthesis of polypyrrole particles, the reaction rate is very fast. In this study, we designed two new reaction fields for the synthesis of spherical polypyrrole nanoparticles. In the first system, oxidative polymerization of monomer droplets infused in a water/oil (W/O) emulsion reaction field was investigated. The second system employed dispersed monomer in an aqueous solution with a low concentration of oxidant in which polymerization was augmented by ultrasonic irradiation. Effective control of the reaction rate was important for enabling the synthesis of fine spherical polypyrrole particles.
Quantitative NMR Spectroscopy and Determination of Polymer Microstructure of Ethylene‐Styrene and Ethylene‐Isobutylene Co‐Polymers
Authors: Kasalo Ruzica , Busch Markus
Published: March 2013

Summary: Quantitative 13C NMR spectroscopy is used to determine reactivity ratios and end group and branching frequency of ethylene‐styrene and ethylene‐isobutylene co‐polymers synthesized at a temperature T = 205 °C and pressure p = 1650 bar at different levels of co‐monomer fraction. In the forefront of the studies quantitative 13C NMR conditions have to be investigated. Optimum conditions are achieved using a relaxation agent Chromium(III) acetylacetonate (Cr(acac)3) at measurement temperature T = 100 °C and a delay time d1 = 7 s with a 90° pulse and inverse‐gated decoupling. The analysis of conversion dependence of co‐monomer content shows an increase in conversion with increasing co‐monomer content for the ethylene‐styrene co‐polymerization, whereas conversion decreases with rising isobutene fraction in the co‐polymer. Reactivity ratios for ethylene‐styrene as well as for ethylene‐isobutylene co‐polymerization system are determined with values rES = 0.09 ± 0.007 and rSE = 2.3 ± 7.0 and rEIB = 3.3 ± 0.6 and rIBE = 6.3 ± 4.2. Frequency on methyl end groups, end‐of‐chain contributions caused by transfer to propionic aldehyde and butyl branches are gained. For the ethylene‐styrene co‐polymer system a decrease in frequency is observed, whereas for the ethylene‐isobutylene co‐polymer system the opposite occurs. Influence of the co‐monomers on the polymerization reaction steps as transfer to chain transfer agent and backbiting reaction is discussed.
Solvent Effect in PLA‐PEG Based Nanoparticles Synthesis through Surfactant Free Polymerization
Authors: Ferrari Raffaele , Cingolani Alberto , Moscatelli Davide
Published: March 2013

Summary: In this work one‐pot synthesis of PEGylated PLA‐based nanoparticles (NPs) without using any surfactant has been performed. Adopting ring opening polymerization of L,L–Lactide and 2‐hydroxyethyl methacrylate (HEMA), vinyl end functionalized poly(lactic acid) macromonomers (HEMA‐LAn) have been produced with tunable number of lactic acid units (larger than 5) and a low molecular weight distribution. Macromonomers have been further copolymerized with modified PEG chains (HEMA‐PEGm) through a monomer starved semi‐batch emulsion polymerization performed without using any surfactant. In these conditions, small and monodispersed NPs of around 150 nm are obtained. Since macromonomers with n larger than 5 are highly viscous at room temperature, they have to be dissolved in a solvent before their injection in the reactor. In this work the effects in changing the solvent adopted in the starved process (water miscible or non‐miscible) and its amount have been investigated. Moreover, the effect of both PEG chains concentration and MW on the final NPs properties has been elucidated. The colloidal stability of the NPs produced using different solvents has been verified in phosphate buffered saline (PBS) solution via dynamic light scattering measurements; in addition the critical coagulation concentration of these PEGylated NPs has been determined.
Encapsulation of Jojoba and Andiroba Oils by Miniemulsion Polymerization. Effect on Molar Mass Distribution
Authors: Cardoso Priscilla B. , Araújo Pedro H. H. , Sayer Claudia
Published: March 2013

Summary: This paper aims to study the encapsulation of jojoba and andiroba oils via miniemulsion polymerization. The effect of different hydrophilic monomers (acrylic or methacrylic acid), co‐stabilizers (hexadecane, jojoba oil or andiroba oil) and initiator concentrations were evaluated. Results indicated the formation of particles with nanocapsule morphology when either hexadecane or jojoba oils were used. When andiroba oil was used no phase separation could be detected in polymer particles and molar mass distributions showed a shoulder of intermediate molar masses between those of the oil and of the pure polymer.
Synthesis of Core‐Shell Particles of Polystyrene and Poly(methyl methacrylate) Using Emulsion Photopolymerization
Authors: Chicoma D. L. , Carranza V. , Giudici R.
Published: March 2013

Summary: Submicron core‐shell particles of polystyrene (PS) and polystyrene‐co‐poly(methyl methacrylate) (PS‐co‐PMMA) coated with PMMA were obtained by emulsion photopolymerization. The seeds of PS or PS‐co‐PMMA were prepared by emulsion polymerization with or without emulsifier and a ratio of functional monomer and crosslinker (SVBS/EDGMA) in order to obtain different surfaces for the subsequent coating with PMMA. At each stage, the evolution of the average particle size were monitored by using photon correlation spectroscopy (DLS) and the final polymer particles was analyzed via transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The core‐shell morphology was identified as the increase of the average particle size in the second stage by DLS technique and by the direct observation by TEM of the differentiation between PS core and PMMA shell, and by the presence of two glass transition temperatures (Tg) as a consequence of the existence of two partially miscible phases.
Is TOR1A a risk factor in adult‐onset primary torsion dystonia?
Authors: Groen Justus L. , Ritz Katja , Tanck Michael W. , van de Warrenburg Bart P. , van Hilten Jacobus J. , Aramideh Majid , Baas Frank , Tijssen Marina A. J.
Published: March 2013

Background

Studies of genetic association between TOR1A and adult‐onset primary torsion dystonia have contradictory results.

Methods

The authors genotyped TOR1A single nucleotide polymorphisms rs1801968, rs2296793, rs1182 and rs3842225 in a cohort of clinically well characterized cervical dystonia patients (n=367) and constructed haplotypes. The authors systematically reviewed the published case‐control TOR1A association studies in adult‐onset primary torsion dystonia.

Results

In this Dutch cervical dystonia cohort, no significant association was found with TOR1A variants. In the meta‐analysis (eight studies, 1332 adult‐onset primary dystonia patients) no variant reached overall significance. However, in a selection of familial cases the functional variant p.Asp216His (rs1801968) was associated with increased dystonia risk (odds ratio 1.43; 95%CI 1.01–2.02).

Conclusions

Meta‐analysis does not show association with common variants in TOR1A in adult‐onset primary dystonia, except for the functional variant rs1801968 in familial focal dystonia cases. © 2013 Movement Disorder Society
Globale Sprengbohrlochtechnik über und unter Tage mit einem Ausblick auf zukünftige Techniken und Abbauentwicklungen
Authors: Wennmohs Karl‐Heinz
Published: March 2013

Die Bohr‐ und Sprengtechnik hat sich innerhalb der weltweiten Bergbauaktivitäten über und unter Tage als eine der effektivsten und sichersten Lösetechniken behauptet. Diese Aussage gilt nicht für Gewinnungsbetriebe, in denen die geologischen Bedingungen eine wirtschaftliche mechanische Lösetechnik zulassen. Der Beitrag gibt einen Überblick über den aktuellen Stand der Sprenglochbohrtechnik für den unter‐ und übertägigen Bergbau. Im Untertagebau kommen in Gesteinsformationen mit Druckfestigkeiten über 100 MPa schlagende Bohrverfahren mit Top‐ und Senkbohrhämmern zum Einsatz. In Tagebauen werden bis zu einer Gesteinsdruckfestigkeit zwischen 80 und 200 MPa bevorzugt Drehbohrverfahren mit Rollenmeißel eingesetzt; bei höheren Druckfestigkeiten kommen Senkbohrhämmer zur Anwendung. Praxisbeispiele zeigen, dass Massenförderung im Tief‐ und Tagebau mithilfe eines hochleistungsfähigen Bohrgeräteparks möglich ist.

Global blast hole drilling technology above and below ground with an outlook to future technologies and developments in extraction

Drill and blast technology has become established as one of the most effective and safe excavation methods in mining worldwide. This statement does not only apply to extraction operations, in which the geological conditions permit the economical use of mechanical excavation. The article offers an overview of the current state of blast hole drilling technology for underground and open cast mining. Below ground, percussion drilling with top or DTH hammers is used in rock formations with compressive strengths over 100 MPa. In open cast mining, rotary drills with disc cutters are preferred up to a rock compressive strength between 80 and 200 MPa; when higher strengths are encountered, DTH hammers are used. Practical examples show that bulk extraction is possible in underground and open cast mining with the assistance of high‐performance drilling machinery.
Flip angle mapping with the accelerated 3D look‐locker sequence
Authors: Wade Trevor , McKenzie Charles A. , Rutt Brian K.
Published: March 2013

Purpose

A new approach to mapping the flip angle quickly and efficiently in 3D based on the Look‐Locker technique is presented.

Methods

We modified the accelerated 3D Look‐Locker T1 measurement technique to allow rapid measurement of flip angle. By removing the inversion pulses and interleaving two radio frequency pulses with different amplitude, it is possible to fit directly for the true flip angle using a reduced number of parameters. This technique, non‐inverted Double Angle Look‐Locker, allows quick and efficient mapping of the flip angle in 3D.

Results

non‐inverted Double Angle Look‐Locker is validated in vitro against the actual flip angle imaging technique for a range of flip angles and T1 values. Flip angle maps produced with non‐inverted Double Angle Look‐Locker can be acquired in approximately 1 min, and are accurate to within 10% of the actual flip angle imaging measurement. It is shown to accurately measure the excited slab profile of several different pulses. An application to correcting in vivo DESPOT T1 data is presented.

Conclusion

The presented technique is a rapid method for mapping flip angles across a 3D volume, capable of producing a flip angle map in approximately 1 min. Magn Reson Med 71:591–598, 2014. © 2013 Wiley Periodicals, Inc.
Abrupt changes in deep Atlantic circulation during the transition to full glacial conditions
Authors: Thornalley David J. R. , Barker Stephen , Becker Julia , Hall Ian R. , Knorr Gregor
Published: March 2013

Six Ocean Drilling Program (ODP) sites, in the Northwest Atlantic have been used to investigate kinematic and chemical changes in the “Western Boundary Undercurrent” (WBUC) during the development of full glacial conditions across the Marine Isotope Stage 5a/4 boundary (~70,000 years ago). Sortable silt mean grain size measurements are employed to examine changes in near bottom flow speeds, together with carbon isotopes measured in benthic foraminifera and % planktic foraminiferal fragmentation as proxies for changes in water‐mass chemistry. A depth transect of cores, spanning 1.8–4.6 km depth, allows changes in both the strength and depth of the WBUC to be constrained across millennial scale events. measurements reveal that the flow speed structure of the WBUC during warm intervals (“interstadials”) was comparable to modern (Holocene) conditions. However, significant differences are observed during cold intervals, with higher relative flow speeds inferred for the shallow component of the WBUC (~2 km depth) during all cold “stadial” intervals (including Heinrich Stadial 6), and a substantial weakening of the deep component (~3–4 km) during full glacial conditions. Our results therefore reveal that the onset of full glacial conditions was associated with a regime shift to a shallower mode of circulation (involving Glacial North Atlantic Intermediate Water) that was quantitatively distinct from preceding cold stadial events. Furthermore, our chemical proxy data show that the physical response of the WBUC during the last glacial inception was probably coupled to basin‐wide changes in the water‐mass composition of the deep Northwest Atlantic.
Surface characterization of novel hydrophobic UV‐vurable siloxane‐modified methacrylate/boehmite nanocomposites
Authors: Corcione Carola Esposito , Frigione Mariaenrica
Published: March 2013

Novel UV‐photopolymerizable siloxane‐modified methacrylate/Boehmite nanocomposites were experimented as possible protective coatings for different substrates. To this aim, unfilled and Boehmite‐filled suspensions were applied and photocured on a glass substrate. A subsequent detailed experimental characterization was performed in order to evaluate the effect of the presence of Boehmite nanoparticles on the surface properties of the coatings and on their durability characteristics. In particular, transparency, glass transition temperature, scratch, and surface hardness, contact angle, and color change were measured on the coatings applied on glass support before and after QUV accelerated weathering cycles. POLYM. COMPOS., 34:1546–1552, 2013. © 2013 Society of Plastics Engineers
Dynamic and capillary shear rheology of natural fiber‐reinforced composites
Authors: Le Moigne Nicolas , van den Oever Martien , Budtova Tatiana
Published: March 2013

An extended dynamic and capillary rheological study of molten flax and sisal polypropylene (PP) composites was performed. Fiber concentration varied from 20 to 50 wt% and shear rate from 0.1 rad s−1 to 10,000 s#142;−1. Maleic anhydride‐grafted‐PP was used as compatibilizer; it strongly reduces PP and composite viscosity. Composites are yield‐stress shear‐thinning fluids with solid‐like behavior being more pronounced at high fiber content. Composites do not obey Cox–Merz rule, which was explained by different macrostructures of the molten composites in parallel plates and capillary die geometries: random fiber orientation versus strong alignment in the flow direction, respectively. Theories describing the viscosity of suspensions of solid particles were applied to the composites studied and rheological parameters and maximal packing fiber volume fraction were calculated. POLYM. ENG. SCI., 53:2582–2593, 2013. ©2013 Society of Plastics Engineers.
Preparation and characterization of high performance exfoliated montmorillonite/silicone rubber nanocomposites with enhanced mechanical properties
Authors: Ismail N.I. Nik , Ansarifar A. , Song M.
Published: March 2013

Highly exfoliated and intercalated silicone rubber (SR) nanocomposites based on natural montmorillonite (Cloisite Na+) and organically modified montmorillonite (Cloisite 30B and Cloisite 20A) were successfully prepared by melt‐mixing technique. Dispersion of the nanoclays in the rubber nanocomposites was subsequently investigated. As indicated by the X‐ray diffraction (XRD) analysis, intercalation, and exfoliation of the clay particles in the nanocomposites was achieved at less than 8 parts per hundred (phr) rubber by weight, irrespective of the initial interlayer spacing of the nanoclay particles. Both Cloisite Na+ and Cloisite 30B were spontaneously transformed into exfoliated microstructures during the vulcanisation stage. Overall, the use of the nanoclays in silicone rubber improved the Young's modulus, tensile strength, and elongation at break by more than 50% as compared with the control rubber. In addition, this work provided a fresh insight into the way intercalated and exfoliated morphologies affect mechanical properties of silicone rubber nanocomposites. It was shown that the exfoliated Cloisite Na+ yielded outstanding mechanical properties with low hysteresis at the same loading of the exfoliated Cloisite 30B and intercalated Cloisite 20A organoclays. As expected, the formation of crosslinks affected the mechanical properties of the rubber vulcanizate significantly. POLYM. ENG. SCI., 53:2603–2614, 2013. © 2013 Society of Plastics Engineers
On‐target ultrasonic digestion of proteins
Authors: Santos Hugo M. , Kouvonen Petri , Capelo Jose‐Luis , Corthals Garry L.
Published: March 2013

In the present work, we report a novel on‐target protein cleavage method. The method utilizes ultrasonic energy and allows up to 20 samples to be cleaved in 5 min for protein identification and one sample in 30 s for on‐tissue digestion. The standard proteins were spotted on a conductive glass slide in a volume of 0.5 μL followed by 5 min of ultrasonication after trypsin addition. Controls (5 min, 37°C no ultrasonication) were also assayed. After trypsin addition, digestion of the tissues was enhanced by 30 s of ultrasonication. The samples were analyzed and compared to those obtained by using conventional 3 h heating proteolysis. The low sample volume needed for the digestion and reduction in sample‐handling steps and time are the features that make this method appealing to the many laboratories working with high‐throughput sample treatment.
An automated in‐gel digestion/iTRAQ‐labeling workflow for robust quantification of gel‐separated proteins
Authors: Schmidt Carla , Hesse Dörte , Raabe Monika , Urlaub Henning , Jahn Olaf
Published: March 2013

Simple protein separation by 1DE is a widely used method to reduce sample complexity and to prepare proteins for mass spectrometric identification via in‐gel digestion. While several automated solutions are available for in‐gel digestion particularly of small cylindric gel plugs derived from 2D gels, the processing of larger 1D gel‐derived gel bands with liquid handling work stations is less well established in the field. Here, we introduce a digestion device tailored to this purpose and validate its performance in comparison to manual in‐gel digestion. For relative quantification purposes, we extend the in‐gel digestion procedure by iTRAQ labeling of the tryptic peptides and show that automation of the entire workflow results in robust quantification of proteins from samples of different complexity and dynamic range. We conclude that automation improves accuracy and reproducibility of our iTRAQ workflow as it minimizes the variability in both, digestion and labeling efficiency, the two major causes of irreproducible results in chemical labeling approaches.
High‐throughput cloning and expression library creation for functional proteomics
Authors: Festa Fernanda , Steel Jason , Bian Xiaofang , Labaer Joshua
Published: March 2013

The study of protein function usually requires the use of a cloned version of the gene for protein expression and functional assays. This strategy is particularly important when the information available regarding function is limited. The functional characterization of the thousands of newly identified proteins revealed by genomics requires faster methods than traditional single‐gene experiments, creating the need for fast, flexible, and reliable cloning systems. These collections of ORF clones can be coupled with high‐throughput proteomics platforms, such as protein microarrays and cell‐based assays, to answer biological questions. In this tutorial, we provide the background for DNA cloning, discuss the major high‐throughput cloning systems (Gateway® Technology, Flexi® Vector Systems, and CreatorTM DNA Cloning System) and compare them side‐by‐side. We also report an example of high‐throughput cloning study and its application in functional proteomics. This tutorial is part of the International Proteomics Tutorial Programme (IPTP12).
A modular design of low‐background bioassays based on a high‐affinity molecular pair barstar:barnase
Authors: Sreenivasan Varun K. A. , Kelf Timothy A. , Grebenik Ekaterina A. , Stremovskiy Oleg A. , Say Jana M. , Rabeau James R. , Zvyagin Andrei V. , Deyev Sergey M.
Published: March 2013

High‐affinity molecular pairs provide a convenient and flexible modular base for the design of molecular probes and protein/antigen assays. Specificity and sensitivity performance indicators of a bioassay critically depend on the dissociation constant (KD) of the molecular pair, with avidin:biotin being the state‐of‐the‐art molecular pair (KD ∼ 1 fM) used almost universally for applications in the fields of nanotechnology and proteomics. In this paper, we present an alternative high‐affinity protein pair, barstar:barnase (KD ∼ 10 fM), which addresses several shortfalls of the avidin:biotin system, including non‐negligible background due to the non‐specific binding. A quantitative assessment of the non‑specific binding carried out using a model assay revealed inherent irreproducibility of the [strept]avidin:biotin‐based assays, attributed to the avidin binding to solid phases, endogenous biotin molecules and serum proteins. On the other hand, the model assays assembled via a barstar:barnase protein linker proved to be immune to such non‐specific binding, showing good prospects for high‐sensitivity rare biomolecular event nanoproteomic assays.
Project Management Knowledge Flows in Networks of Project Managers and Project Management Offices: A Case Study in the Pharmaceutical Industry
Authors: Müller Ralf , Glückler Johannes , Aubry Monique , Shao Jingting
Published: March 2013

This study investigates the knowledge flows among and between project managers and project management office (PMO) members in a pharmaceutical R&D company in China, using a mixed-methods approach. The results show that knowledge exchange happens in clusters, where each cluster forms around a PMO member. Contrary to expectations, PMO members were not identified as the most popular knowledge providers in these clusters; instead, knowledge was requested from earlier collaborators. A three-tiered model is developed for knowledge governance at the cluster level, across clusters and the link with corporate and project governance structures. Managerial and theoretical implications are discussed.
Ionic electroactive polymer metal composites: Fabricating, modeling, and applications of postsilicon smart devices
Authors: De Luca Viviana , Digiamberardino Paolo , Di Pasquale Giovanna , Graziani Salvatore , Pollicino Antonino , Umana Elena , Xibilia Maria Gabriella
Published: March 2013

Smart systems adapt to the surrounding environments in a number of ways. They are capable to scavenge energy from available sources, sense and elaborate external stimuli and adequately react. Electro Active Polymers are playing a main role in the realization of smart systems for applications if fields such as bio inspired and autonomous robotics, medicine, and aerospace. This paper focus on the possibility to use Ionic Polymer Metal Composites as a class of materials relevant to the realization of post silicon smart systems. The three main aspects of this new technology, i.e., fabrication methods, modeling, and applications are described with emphasis to most recent results. Attention is given to main challenges and shortcomings to be solved for technology, modelling, and control of IPMC based devices that need to be solved before this new technology can be fully exploited in real world applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013
Mean Particle Diameters. Part VII. The Rosin‐Rammler Size Distribution: Physical and Mathematical Properties and Relationships to Moment‐Ratio Defined Mean Particle Diameters
Authors: Alderliesten Maarten
Published: March 2013

The Rosin‐Rammler particle size distribution is used for a broad range of applications. Physical and statistical properties of the Rosin‐Rammler distribution and its parameters were investigated to evaluate their suitability in the particulate area. The Rosin‐Rammler volume density distribution is identical to the Weibull density distribution describing material failure and fatigue phenomena. The physical meaning of the Rosin‐Rammler location parameter depends on the value of its spread parameter. This makes the location parameter physically uninterpretable and less suitable for development of physical models. The distribution can still be used for, e.g., production control purposes. Rosin‐Rammler distributions with spread parameter values less than three cannot exist. They can at most give a rough description of size distributions within the measured particle size range. They should not be expected to describe correctly the quantity of small particles outside the measured size range. Their parameters are unsuitable for model development aiming at estimating parameters explaining/predicting physical product or process parameters. Two data sets were used for validation. Mean particle diameters (Moment‐Ratio notation) and the Rosin‐Rammler parameters are mathematically related, but the relationship is not valid for mean parameter values of a set of size distributions. It is not possible to predict a type of mean particle diameter showing a behavior close to that of the Rosin‐Rammler location parameter. For both data sets, the quality of the relationship of physical product property with proper mean particle diameter type is better than that with the Rosin Rammler location parameter. For process control applications a replacement of the Rosin‐Rammler location parameter by a mean particle diameter (Moment‐Ratio) should be considered. The type of mean particle diameter to be chosen depends on the values of the Rosin‐Rammler spread parameter occurring in the process. Two steps in the migration path are identified.
Oligomeric states of the Shigella translocator protein IpaB provide structural insights into formation of the type III secretion translocon
Authors: Dickenson Nicholas E. , Choudhari Shyamal P. , Adam Philip R. , Kramer Ryan M. , Joshi Sangeeta B. , Middaugh C. Russell , Picking Wendy L. , Picking William D.
Published: March 2013

The Shigella flexneri Type III secretion system (T3SS) senses contact with human intestinal cells and injects effector proteins that promote pathogen entry as the first step in causing life threatening bacillary dysentery (shigellosis). The Shigella Type III secretion apparatus (T3SA) consists of an anchoring basal body, an exposed needle, and a temporally assembled tip complex. Exposure to environmental small molecules recruits IpaB, the first hydrophobic translocator protein, to the maturing tip complex. IpaB then senses contact with a host cell membrane, forming the translocon pore through which effectors are delivered to the host cytoplasm. Within the bacterium, IpaB exists as a heterodimer with its chaperone IpgC; however, IpaB's structural state following secretion is unknown due to difficulties isolating stable protein. We have overcome this by coexpressing the IpaB/IpgC heterodimer and isolating IpaB by incubating the complex in mild detergents. Interestingly, preparation of IpaB with n‐octyl‐oligo‐oxyethylene (OPOE) results in the assembly of discrete oligomers while purification in N,N‐dimethyldodecylamine N‐oxide (LDAO) maintains IpaB as a monomer. In this study, we demonstrate that IpaB tetramers penetrate phospholipid membranes to allow a size‐dependent release of small molecules, suggesting the formation of discrete pores. Monomeric IpaB also interacts with liposomes but fails to disrupt them. From these and additional findings, we propose that IpaB can exist as a tetramer having inherent flexibility, which allows it to cooperatively interact with and insert into host cell membranes. This event may then lay the foundation for formation of the Shigella T3SS translocon pore.
Bacterial microcompartment shells of diverse functional types possess pentameric vertex proteins
Authors: Wheatley Nicole M. , Gidaniyan Soheil D. , Liu Yuxi , Cascio Duilio , Yeates Todd O.
Published: March 2013

Bacterial microcompartments (MCPs) are large proteinaceous structures comprised of a roughly icosahedral shell and a series of encapsulated enzymes. MCPs carrying out three different metabolic functions have been characterized in some detail, while gene expression and bioinformatics studies have implicated other types, including one believed to perform glycyl radical‐based metabolism of 1,2‐propanediol (Grp). Here we report the crystal structure of a protein (GrpN), which is presumed to be part of the shell of a Grp‐type MCP in Rhodospirillum rubrum F11. GrpN is homologous to a family of proteins (EutN/PduN/CcmL/CsoS4) whose members have been implicated in forming the vertices of MCP shells. Consistent with that notion, the crystal structure of GrpN revealed a pentameric assembly. That observation revived an outstanding question about the oligomeric state of this protein family: pentameric forms (for CcmL and CsoS4A) and a hexameric form (for EutN) had both been observed in previous crystal structures. To clarify these confounding observations, we revisited the case of EutN. We developed a molecular biology‐based method for accurately determining the number of subunits in homo‐oligomeric proteins, and found unequivocally that EutN is a pentamer in solution. Based on these convergent findings, we propose the name bacterial microcompartment vertex for this special family of MCP shell proteins.
Noradrenaline induces binding of Clathrin light chain A to α1‐adrenoceptors in the human prostate
Authors: Hennenberg Martin , Miersch Josef , Rutz Beata , Strittmatter Frank , Waidelich Raphaela , Stief Christian G. , Gratzke Christian
Published: March 2013

BACKGROUND

Binding of clathrins or caveolin to G protein‐coupled receptors may induce post‐translational modifications of receptor function. Receptor regulation by clathrin requires cofactors ADP‐ribosylation factor 6 (ARF6) and adaptin, while dynamin is required for clathrin‐ and caveolin‐dependent mechanisms.

OBJECTIVE

To investigate the expression and α1‐adrenoceptor binding of clathrins, caveolin, and their cofactors in the human prostate.

METHODS

Prostate tissue was obtained from radical prostatectomy. Expression of clathrin heavy chain (HC), clathrin light chain A and B (LCA, LCB), caveolin‐1, ARF6, β‐adaptin, and dynamin‐2 was studied by RT‐PCR, Western blot, immunohistochemistry, and fluorescence staining. Interaction of α1A‐adrenoceptors with clathrins and caveolin‐1 was studied by coimmunoprecipitation.

RESULTS

mRNA and protein expression of clathrin HC, LCA, LCB, caveolin‐1, dynamin‐2, and β‐adaptin was detected in prostate tissues of each patient. Immunohistochemistry demonstrated the expression of clathrin HC, LCA, LCB, caveolin, dynamin, and β‐adaptin in stromal cells. Immunoreactivity for these proteins colocalized with α‐smooth muscle actin and α1A‐adrenoceptors in double fluorescence staining. Coimmunoprecipitation demonstrated that α1A‐adrenoceptors in prostate tissue interact with clathrin HC and LCB under resting conditions, but not with caveolin‐1. Stimulation of prostate tissues with noradrenaline (30 µM) in vitro induced binding of clathrin LCA to α1A‐adrenoceptors.

CONCLUSIONS

The prostatic α1‐adrenoceptor population is at least partially bound to clathrin HC and LCB. Upon receptor activation, prostate α1A‐adrenoceptors bind clathrin LCA. This points to a new concept of post‐translational α1‐adrenoceptor regulation in the prostate, which includes receptor interaction with accessory binding partners. Prostate 73: 715–723, 2013. © 2013 Wiley Periodicals, Inc.
Preparation of epitaxial films of the transparent conductive oxide Al:ZnO by reactive high‐pressure sputtering in Ar/O2 mixtures
Authors: Van Gompel M. , Conings B. , Jiménez Monroy K. L. , D‘Haen J. , Gilissen K. , D‘Olieslaeger M. , Van Bael M. K. , Wagner P.
Published: March 2013

Transparent conductive metal oxides are interesting materials for various optoelectronic applications including solar cells and flat panel displays. This study focuses on the in situ deposition of aluminum‐doped zinc oxide (AZO) thin layers on c‐axis oriented sapphire substrates by dc sputtering and on the structural and electrical characterization. The films have a typical thickness of 90 nm and a roughness of 10 nm root mean square. An Al/Zn ratio of 2.4 at% Al was determined by X‐ray photoelectron spectroscopy. X‐ray diffraction shows a preferential growth in the (0002) c‐axis direction. Films have an average transparency of 90% in the visible‐light spectrum, a room‐temperature resistivity of 3.7 × 10−3 Ω cm and a carrier mobility of 6.7 cm2 V−1 s−1.
THz photoconductivity in a‐Si:H
Authors: Shimakawa Koichi , Wagner Tomas , Frumar Miloslav
Published: March 2013

magnified image

Although the steady‐state secondary photoconductivity in amorphous semiconductors is fairly well understood, photocarrier transport with a subpicosecond time resolution (the THz region in the frequency domain) is still not clear. The frequency response of short‐lived photocarriers in the THz region is discussed in a‐Si:H here. It is shown that THz‐photoconductivity is highly influenced by the mesoscopic inhomogeneity (10‐nm scale) originating from potential fluctuations. This behavior is basically the same as observed in the radio‐frequency (RF) range.
Optical probe for surface and subsurface defects induced by ion bombardment
Authors: Sun L. D. , Hohage M. , Zeppenfeld P.
Published: March 2013

We demonstrate that reflectance difference spectroscopy (RDS) is sensitive to defects induced by ion bombardment, located either in the topmost layer or in the subsurface region. Most importantly, these two kinds of defects can be spectrally discriminated, since the corresponding signatures in the RD spectrum arise from perturbations of different types of electronic states: The defects in the topmost surface layer mainly lead to a quenching of the optical anisotropy related to surface states, whereas the subsurface defects strongly affect the optical anisotropy originating from transitions between surface‐modified bulk electronic states. Consequently, RDS can be used to simultaneously monitor the defects in the topmost surface layer and in the subsurface region in‐situ during ion bombardment and thermal annealing.

magnified image

Characteristic RD spectra and the corresponding STM images for a Cu(110) substrate before and after healing of the subsurface defects.

(© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
H2S splitting on Cu(110): Insight from combined periodic density functional theory calculations and microkinetic simulation
Authors: Tang Qian‐Lin
Published: March 2013

Practical copper (Cu)‐based catalysts for the water–gas shift (WGS) reaction was long believed to expose a large proportion of Cu(110) planes. In this work, as an important first step toward addressing sulfur poisoning of these catalysts, the detailed mechanism for the splitting of hydrogen sulfide (H2S) on the open Cu(110) facet has been investigated in the framework of periodic, self‐consistent density functional theory (DFT‐GGA). The microkinetic model based on the first‐principles calculations has also been developed to quantitatively evaluate the two considered decomposition routes for yielding surface atomic sulfur (S*): (1) H2S → H2S* → SH* → S* and (2) 2H2S → 2H2S* → 2SH* → S* + H2S* → S* + H2S. The first pathway proceeding through unimolecular SH* dissociation was identified to be feasible, whereas the second pathway involving bimolecular SH* disproportionation made no contribution to S* formation. The molecular adsorption of H2S is the slowest elementary step of its full decomposition, being related with the large entropy term of the gas‐phase reactant under realistic reaction conditions. A comparison of thermodynamic and kinetic reactivity between the substrate and the close‐packed Cu(111) surface further shows that a loosely packed facet can promote the S* formation from H2S on Cu, thus revealing that the reaction process is structure sensitive. The present DFT and microkinetic modeling results provide a reasonably complete picture for the chemistry of H2S on the Cu(110) surface, which is a necessary basis for the design of new sulfur‐tolerant WGS catalysts. © 2013 Wiley Periodicals, Inc.
Validation of the femoral component placement during hip resurfacing: a comparison between the conventional jig, patient‐specific template, and CT‐based navigation
Authors: Kitada Makoto , Sakai Takashi , Murase Tsuyoshi , Hanada Toshihisa , Nakamura Nobuo , Sugano Nobuhiko
Published: March 2013

Background

Appropriate insertion of a femoral guidewire is essential for hip resurfacing. A simulation study was planned using synthetic femoral bone models and the accuracy and precision of femoral guidewire alignment and insertion point were compared between conventional jigs, patient‐specific templates, and computed tomography (CT) based navigation techniques.

Methods

Anteversion, stem‐shaft angle, and the three‐dimensional insertion point were measured postoperative with CT. Errors between planned and postoperative measurement and precision were evaluated.

Results

There were no statistically significant differences in error for anteversion or insertion point, although the mechanical jig showed greater error in the stem‐shaft angle than the others. Patient‐specific template and CT‐based navigation showed good precision with high intraclass correlation (ICC) (template, 0.908 to 1.000; navigation, 0.929 to 0.995) and small root mean square error (RMSE) (0.954 to 2.969; 1.468 to 3.213). The mechanical jig group performance was inferior to the others.

Conclusions

Patient‐specific templates and CT‐based navigation had good accuracy and precision. The mechanical jig technique was inferior to the others. Copyright © 2013 John Wiley & Sons, Ltd.
Tracking and Following a Tagged Leopard Shark with an Autonomous Underwater Vehicle
Authors: Clark Christopher M. , Forney Christina , Manii Esfandiar , Shinzaki Dylan , Gage Chris , Farris Michael , Lowe Christopher G. , Moline Mark
Published: March 2013

This paper presents a prototype system that enables an autonomous underwater vehicle (AUV) to autonomously track and follow a shark that has been tagged with an acoustic transmitter. The AUV's onboard processor handles both real‐time estimation of the shark's two‐dimensional planar position, velocity, and orientation states, as well as a straightforward control scheme to drive the AUV toward the shark. The AUV is equipped with a stereo‐hydrophone and receiver system that detects acoustic signals transmitted by the acoustic tag. The particular hydrophone system used here provides a measurement of relative bearing angle to the tag, but it does not provide the sign (+ or −) of the bearing angle. Estimation is accomplished using a particle filter that fuses bearing measurements over time to produce a state estimate of the tag location. The particle filter combined with a heuristic‐based controller allows the system to overcome the ambiguity in the sign of the bearing angle. The state estimator and control scheme were validated by tracking both a stationary tag and a moving tag with known positions. Offline analysis of these data showed that state estimation can be improved by optimizing diffusion parameters in the prediction step of the filter, and considering signal strength of the acoustic signals in the resampling stage of the filter. These experiments revealed that state estimate errors were on the order of those obtained by current long‐distance shark‐tracking methods, i.e., manually driven boat‐based tracking systems. Final experiments took place in SeaPlane Lagoon, Los Angeles, where a 1‐m leopard shark (Triakis semifasciata) was caught, tagged, and released before being autonomously tracked and followed by the proposed AUV system for several hours. © 2013 Wiley Periodicals, Inc.
Interference percolation
Authors: Balister Paul , Bollobás Béla
Published: March 2013

Let G be an infinite connected graph with minimum degree δ and maximum degree Δ. Let Gp be a random induced subgraph of G obtained by selecting each vertex of G independently with probability p, , and let be the induced subgraph of Gp obtained by deleting all vertices of Gp with degree greater than k in Gp. We show that if and is not too large then almost surely has no infinite component. Moreover, this result is essentially best possible since there are examples where has an infinite component (a) when , 4, or 5, and k = 3; (b) when for any δ and k = 3; and (c) when for any and . In addition, we show that if G is the d‐dimensional lattice then almost surely has an infinite component for sufficiently large d. © 2014 Wiley Periodicals, Inc. Random Struct. Alg. 44, 399–418, 2014
How Strategic Entrepreneurship and The Institutional Context Drive Economic Growth
Authors: Bjørnskov Christian , Foss Nicolai
Published: March 2013

The economics of growth has shown that countries grow by better allocating whatever resources are at their disposal and by introducing productivity‐enhancing innovations. Strategic entrepreneurship plays a key role in this process by searching for, combining, trying out, etc., new resource combinations in the pursuit of profits under uncertainty. Institutions that support economic freedom allow such experimentation to take place at low transaction costs, positively influencing total factor productivity. We test these ideas on a unique panel data set derived from Compendia, World Bank data, and the Fraser Institute's economic freedom data. Copyright © 2013 Strategic Management Society.
Waldschlößchenbrücke in Dresden – Ausführungsplanung des Überbaus
Authors: Klähne Thomas , Einhäuser Oliver
Published: March 2013

Die Waldschlößchenbrücke in Dresden ist die lang gedachte, nun erbaute neue Elbquerung, über deren Notwendigkeit schon unsere Vorväter diskutierten – die Diskussionen brechen bis heute nicht ab. Sie sind politischer, ästhetischer, wirtschaftlicher und technischer Art.

Die Brücke ist ein markantes Zeichen deutscher Ingenieurkunst. Sie ist geometrisch anspruchsvoll und daher in ihrer Konstruktion sehr detailreich. In ihrer Herstellung und Montage war sie ein mutiges Unterfangen. Im vorliegenden Beitrag wird über die technische Bearbeitung und Ausführung des Stahlverbundüberbaus sowie der stählernen Stützen berichtet.

The Waldschlößchen Bridge in Dresden, Germany – Plan of execution of the superstructure. The Waldschlößchen Bridge in Dresden is the long imagined, now built, crossing of the river Elbe, the necessity of which was already discussed by our forefathers. The discussion continues to this day. They were and are of political, aesthetical, economical and technical character. The new bridge is a remarkable example of German engineering. It is geometrically challenging, hence very detailed in the construction, which made the manufacture and installation a bold undertaking. This paper will cover the technical process and execution of both the composite steel superstructure, and the steel supports.