bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: Chemistry of Renewable Carbon‐Based Raw Materials for the Production of Chemicals and Fuels
Authors: Vogel G. Herbert
Published: May 2015

Review: 101 refs.
The gut microbiome: What do we know?
Authors: Guarner Francisco
Published: May 2015

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Potent, Metabolically Stable 2‐Alkyl‐8‐(2H‐1,2,3‐triazol‐2‐yl)‐9H‐adenines as Adenosine A2A Receptor Ligands
Authors: Pace Silvia , Brogin Giandomenico , Stasi Maria Antonietta , Riccioni Teresa , Borsini Franco , Capocasa Francesca , Manera Francesco , Tallarico Carlo , Grossi Pietro , Vacondio Federica , Bassi Michele , Bartoccini Francesca , Lucarini Simone , Piersanti Giovanni , Tarzia Giorgio , Cabri Walter , Minetti Patrizia
Published: May 2015

Inhibition of adenosine A2A receptors has been shown to elicit a therapeutic response in preclinical animal models of Parkinson’s disease (PD). We previously identified the triazolo‐9H‐purine, ST1535, as a potent A2AR antagonist. Studies revealed that ST1535 is extensively hydroxylated at the ω‐1 position of the butyl side chain. Here, we describe the synthesis and evaluation of derivatives in which the ω‐1 position has been substituted (F, Me, OH) in order to block metabolism. The stability of the compounds was evaluated in human liver microsomes (HLM), and the affinity for A2AR was determined. Two compounds, (2‐(3,3‐dimethylbutyl)‐9‐methyl‐8‐(2H‐1,2,3‐triazol‐2‐yl)‐9H‐purin‐6‐amine (3 b) and 4‐(6‐amino‐9‐methyl‐8‐(2H‐1,2,3‐triazol‐2‐yl)‐9H‐purin‐2‐yl)‐2‐methylbutan‐2‐ol (3 c), exhibited good affinity against A2AR (Ki=0.4 nM and 2 nM, respectively) and high in vitro metabolic stability (89.5 % and 95.3 % recovery, respectively, after incubation with HLM for two hours).
A wideband low‐spur 0.18‐µm CMOS phase‐locked loop with bandwidth calibration
Authors: Yu Yueh‐Hua , Chen Yi‐Jan Emery
Published: May 2015

This paper presents a 0.18‐µm complementary metal‐oxide‐semiconductor wideband phase‐locked loop with low reference spurs. The dual‐level charge‐pump current calibration technique is proposed to maintain a constant loop bandwidth for wide operation frequency range and achieve low reference spurs. The first level charge‐pump current calibration is seamlessly incorporated in the automatic frequency band hopping control and the mechanism also ensures enough negative transconductance for the voltage‐controlled oscillator to function throughout the whole frequency range. The charge‐pump current mismatch is calibrated by the second level charge‐pump current calibration combined with the pulse‐width scaling technique. The operation frequency range of the phase‐locked loop covers from 4.7 GHz to 6.1 GHz. The measured phase noise is−116 dBc/Hz at 1‐MHz offset and the reference spurs are below−66.8 dBc. Copyright © 2015 John Wiley & Sons, Ltd.
R‐11‐based power control approach for overlaid femtocell networks
Authors: Sambanthan Padmapriya , Muthu Tamilarasi
Published: May 2015

Short range, low power, plug‐and‐play femtocell has carved a niche for itself because of its potential for higher rate indoor voice and data service, coverage enhancement over cell edges, high network capacity, and negligible greenhouse gas emission. The frequency reuse phenomenon in two‐tier cellular network subjects the cell‐edge macrouser to severe downlink interference from co‐channel deployed femtocells in the same province. Downlink power control approach is a recommended remedy to overcome such type of interferences. This paper proposes release‐11‐based maximum downlink power control (R‐11‐based MDPC) approach to protect macrouser's service from co‐channel interference. The feedback strategy incorporated in this paper is formulated by R‐11 of 3rd Generation Partnership Program for Long Term Evolution standard. Implementation of new R‐11‐based feedback strategy between femto‐base station and macro‐base station with MDPC approach ensures instantaneous power control with minimal feedback delay, higher signal‐to‐interference‐plus‐noise ratio (SINR), simple receiver module design, and better service availability. Simulation results of R‐11‐based MDPC approach clearly indicate reduced feedback delay, better power control with minimal interference, improved SINR, and negligible outage probability. Copyright © 2015 John Wiley & Sons, Ltd.
Intramandibular glands in different castes of leaf‐cutting Ant, Atta laevigata (Fr. Smith, 1858) (Formicidae: Attini)
Authors: Martins Luiza Carla Barbosa , Della Lucia Terezinha Maria Castro , Gonçalves Wagner Gonzaga , Delabie Jacques Hubert Charles , Zanuncio José cola , Serrão José Eduardo
Published: May 2015

Intramandibular glands have been poorly studied in polymorphic ants, where the differences between castes were unsufficiently scrutinized. Leaf‐cutting ants possess one of the most complex systems of communication and labor division, which is polymorphic well as age polyethism, and makes them an ideal model for the study of intramandibular glands. This study has investigated the occurrence of intramandibular glands in female castes and subcastes of Atta laevigata. The mandibles of the queen, medium, and minor workers, and soldiers were submitted to histological, histochemical, ultrastructural, and morphometric analyses. The class‐3 gland cells and the epidermal gland with a reservoir were found in all the castes. The queens and soldiers showed a higher number of class‐3 gland cells, distributed within the mandible as well as a greater gland size in comparison to the workers. The histochemical tests, periodic acid‐Schiff (PAS), mercury‐bromophenol, and Nile blue, were similar for the class‐3 gland cells and epidermal glands with a reservoir. However, the tests evidenced differences between the castes, with carbohydrates strongly positive in all of them, whereas neutral lipids were found in the queen and soldiers. The protein was weakly positive in the queen, whereas in the soldier, medium, and minor workers these reactions were strongly positive in the intramandibular glands. Our findings in A. laevigata suggest that intramandibular glands are directly involved in labor division and consequently in chemical communication between the castes. Microsc. Res. Tech. 78:603–612, 2015. © 2015 Wiley Periodicals, Inc.
Nano‐domains formation on photoalignment thin film by self‐organized dewetting
Authors: Lee Chung‐Yung , Li Yuet‐Wing , Tseng Man‐Chun , Chigrinov Vladimir G. , Kwok Hoi‐Sing
Published: May 2015

A novel discontinuous photoalignment surface with nano‐domains for liquid crystal is developed. The formation of the discontinuous structure is created by self‐organized dewetting, which is regarded as one of the most promising bottom‐up approaches to fabricate nano‐structure. Different dewetting conditions, such as surface roughness, thickness and viscosity, have been investigated. Such discontinuous photoalignment layer can be fabricated on top of another continuous alignment layer to form a new kind of heterogeneous nano‐structured alignment surface – stacked alignment layers. This heterogeneous alignment surface can be used to produce arbitrary pretilt angles for the liquid crystal display. Simulation model has been built to understand the dewetting mechanism. Experiments using photo‐aligned and photo‐polymerisable polymer have been done to verify the dewetting theory. The produced stacked alignment layers are proved to be robust. Moreover, the dewetting processing is a fully controllable process and is compatible with existing manufacturing techniques.
Impact of delayed lymphoscintigraphy for sentinel lymphnode biopsy for breast cancer
Authors: Wang Hanghang , Heck Karissa , Pruitt Scott K. , Wong Terence Z. , Scheri Randall P. , Georgiade Gregory S. , Ichite Ikwunze , Hwang E. Shelley
Published: May 2015

Background

Despite universal adoption of sentinel lymph node biopsy (SLNB) for breast cancer, there remains no standardized protocol for preoperative lymphoscintographic assessment of sentinel nodes. Both immediate and delayed lymphoscintigraphy are currently utilized, although it is unclear how delayed imaging impacts SLN identification.

Methods

Among patients diagnosed with breast cancer who underwent SLNB at Duke from 2011 to 2012, two protocols for preoperative lymphoscintigraphy were used: protocol A included both immediate and delayed lymphoscintigraphy (n = 152), while protocol B involved immediate lymphoscintigraphy only (n = 103).

Results

The overall intraoperative SLN identification rate was 98.4% and did not differ between groups. A lower number of SLN were visualized on the immediate scan using protocol A compared to protocol B (P < 0.001). Although a greater total number of nodes was excised using protocol A, this result was not statistically significant (P = 0.08). Moreover, there was no significant difference in the number of negative SLN between groups (P = 0.51).

Conclusions

We found no significant impact on identification rate or number of SLN excised with the use of delayed versus immediate imaging. These findings support abandoning delayed lymphoscintographic imaging, except in those cases where aberrant drainage is suspected. J. Surg. Oncol. 2015 111:931–934. © 2015 Wiley Periodicals, Inc.
Reinforcing an Injectable Gelatin Hydrogel with PLLA Microfibers: Two Routes for Short Fiber Production
Authors: Poveda‐Reyes Sara , Mellera‐Oglialoro Leonardo Rubén , Martínez‐Haya Rebeca , Gamboa‐Martínez Tatiana Carolina , Gómez Ribelles Jose Luís , Gallego Ferrer Gloria
Published: May 2015

Short poly‐l‐lactic acid (PLLA) microfibers have been produced in order to disperse them into the gelatin solution and enable injection in the tissue defect prior to gel formation. Two methods for fabrication of loose fibers with submicrometric dimensions are presented in this paper. One is based on manufacturing electrospun meshes and subsequent milling (PLLA‐ES) and the other involves projection of a PLLA solution into a high turbulent non‐solvent medium (PLLA‐HT). Composites produced with PLLA‐ES show a compression Young's modulus from 2.65 kPa for the pure gelatin to 6.69 kPa for the composite with 1.5% PLLA‐ES fibers. The new injectable gelatin–fiber composites are not cytotoxic.
Positive Affect and Malleable Mental Accounting: An Investigation of the Role of Positive Affect in Flexible Expense Categorization and Spending
Authors: Loureiro Yuliya Komarova , Haws Kelly L.
Published: May 2015

The present research examines the impact of positive affect on mental accounting and the underlying mechanisms. The authors find that individuals in a positive (vs. neutral) affective state are less likely to exploit ambiguity in mental accounts and justify spending, but only when processing resources are unconstrained. In contrast, when processing resources are limited (high cognitive load), those in a positive (vs. neutral) affective state are more likely to spend. These findings offer new insights into the interplay between affect and cognition in decision making, the use of mental accounting strategies, and the role of affect in spending and self‐control.
A new role for α‐synuclein in Parkinson's disease: Alteration of ER–mitochondrial communication
Authors: Guardia‐Laguarta Cristina , Area‐Gomez Estela , Schon Eric A. , Przedborski Serge
Published: May 2015

Familial cases of Parkinson's disease (PD) can be associated with overexpression or mutation of α‐synuclein, a synaptic protein reported to be localized mainly in the cytosol and mitochondria. We recently showed that wild‐type α‐synuclein is not present in mitochondria, as previously thought, but rather is located in mitochondrial‐associated endoplasmic reticulum membranes. Remarkably, we also found that PD‐related mutated α‐synuclein results in its reduced association with mitochondria‐associated membranes, coincident with a lower degree of apposition of endoplasmic reticulum with mitochondria and an increase in mitochondrial fragmentation, as compared with wild‐type. This new subcellular localization of α‐synuclein raises fundamental questions regarding the relationship of α‐synuclein to mitochondria‐associated membranes function, in both normal and pathological states. In this article, we attempt to relate aspects of PD pathogenesis to what is known about mitochondria‐associated membranes' behavior and function. We hypothesize that early events occurring in dopaminergic neurons at the level of the mitochondria‐associated membranes could cause long‐term disturbances that lead to PD. © 2015 International Parkinson and Movement Disorder Society
Fast rotary nonlinear spatial acquisition (FRONSAC) imaging
Authors: Wang Haifeng , Tam Leo K. , Constable R. Todd , Galiana Gigi
Published: May 2015

Purpose

Nonlinear spatial encoding magnetic fields (SEMs) have been studied to reconstruct images from a minimum number of echoes. Previous work has also explored single shot trajectories in nonlinear SEMs. However, the search continues for optimal schemes that apply nonlinear SEMs to improve spatial encoding efficiency and image quality.

Theory and Methods

We enhance the encoding efficiency of standard linear gradient trajectories by adding a rapidly rotating nonlinear SEM of moderate amplitude, the so called FRONSAC (Fast ROtary Nonlinear Spatial ACquisition) imaging. This additional gradient greatly improves the image quality of highly undersampled single‐shot trajectories, including EPI, Spiral, and Rosette trajectories.

Results

Our simulations, including noise and dephasing effects, test the effect of adding FRONSAC gradients, demonstrating the applicability of this approach. Performance is explained by demonstrating the additional k‐space sampling the nonlinear gradient provides. Studies of the optimal amplitude and frequency of the additional FRONSAC field are presented, and the role of enhanced sampling during the readout demonstrated. Dynamic field mapping in a second‐order gradient system shows the proposed gradient waveforms are feasible.

Conclusion

Images resulting from highly undersampled existing k‐space trajectories, such as EPI, Spiral, and Rosette, are greatly enhanced simply by adding a rotating nonlinear SEM field. Magn Reson Med 75:1154–1165, 2016. © 2015 Wiley Periodicals, Inc.
Simultaneous FETI and block FETI: Robust domain decomposition with multiple search directions
Authors: Gosselet Pierre , Rixen Daniel , Roux François‐Xavier , Spillane Nicole
Published: May 2015

Domain decomposition methods often exhibit very poor performance when applied to engineering problems with large heterogeneities. In particular, for heterogeneities along domain interfaces, the iterative techniques to solve the interface problem are lacking an efficient preconditioner. Recently, a robust approach, named finite element tearing and interconnection (FETI)–generalized eigenvalues in the overlaps (Geneo), was proposed where troublesome modes are precomputed and deflated from the interface problem. The cost of the FETI–Geneo is, however, high. We propose in this paper techniques that share similar ideas with FETI–Geneo but where no preprocessing is needed and that can be easily and efficiently implemented as an alternative to standard domain decomposition methods. In the block iterative approaches presented in this paper, the search space at every iteration on the interface problem contains as many directions as there are domains in the decomposition. Those search directions originate either from the domain‐wise preconditioner (in the simultaneous FETI method) or from the block structure of the right‐hand side of the interface problem (block FETI). We show on two‐dimensional structural examples that both methods are robust and provide good convergence in the presence of high heterogeneities, even when the interface is jagged or when the domains have a bad aspect ratio. The simultaneous FETI was also efficiently implemented in an optimized parallel code and exhibited excellent performance compared with the regular FETI method. Copyright © 2015 John Wiley & Sons, Ltd.
Breast cancer heterogeneity: parallel evolution or conscious uncoupling?
Authors: Natrajan Rachael C
Published: May 2015

Breast cancer is known to display considerable inter‐ and intra‐tumour genetic heterogeneity. It is now widely accepted that no two breast cancers harbour the same complement of genomic alterations, and that both primary and metastatic breast cancers are composed of multiple genetically diverse subclones that evolve under different selective pressures. Recent work published in the Journal of Pathology by Desmedt and colleagues questions the evolutionary dynamics of multi‐focal breast cancer with similar pathological features by studying the mutational repertoire of different lesions. Whilst the majority of the lesions showed some common driver alterations, one‐third lacked any common mutations, suggesting very early clonal divergence. These and other recent observations underscore the need for a fundamental understanding of the rules governing breast cancer evolution, and highlight the need for in‐depth assessment of driver alterations for appropriate patient management and selective treatment. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Effects of alkaline conditioning and temperature on the properties of glass fiber polymer composite rebar
Authors: Ahmad Sawpan Moyeenuddin
Published: May 2015

This article investigated long term alkaline conditioning and temperature on the physical and mechanical properties of glass fiber‐reinforced polymer (GFRP) composite rebar for structural applications. The GFRP rebar was immersed in alkaline solution (pH ≈ 13) for 23 months at 23°C, and for 24 months at 60°C. The moisture absorption was found to be 0.34% at 23°C after 23 months, and 0.76% at 60°C after 24 months. At both temperatures, moisture absorption did not reach equilibrium which was attributed to two stages non‐Fickian behavior. Glass transition temperature (Tg) of the polymer matrix of rebar that conditioned at 23°C was found to be decreased because of plasticization, whereas Tg of the rebar that conditioned at 60°C was remained greater than the Tg of control rebar due to nonplasticization effect. Shear strength was retained by 83.5% at 23°C and 80.5% at 60°C, flexural strength was retained by 81% at 23°C and 69% at 60°C, and tensile strength was retained by 91.2% at 23°C and 74.3% at 60°C. It was revealed that durability of GFRP rebar in alkaline environment was controlled by the absorbed moisture; this was because the load transfer efficiency of fiber/matrix interface is vulnerable to moisture. POLYM. COMPOS., 37:3181–3190, 2016. © 2015 Society of Plastics Engineers
Effects of injection molding conditions on the electrical properties of polycarbonate/carbon nanotube nanocomposites
Authors: Qiu Jianhui , Wang Lijun , Uchiya Kengo , Sakai Eiichi
Published: May 2015

Polycarbonate/Carbon nanotube (PC/CNT) nanocomposites containing various CNT contents (0–5 wt%) were prepared by injection molding. The effects of CNT contents, injection speed (V) and injection temperature (T) on the electrical resistivity of the PC/CNT nanocomposites were investigated. It was found that the tensile strength of nanocomposites was enhanced slightly with increased CNT contents, and the tensile modulus was 29% greater after the 5 wt% CNT addition, but the brittle tendency became stronger. Aside from tensile properties, the electrical resistivity of the nanocomposites dropped 12 orders of magnitude after the 5 wt% CNT addition. Also, there was a tendency that the electrical resistivity was lower in the case of higher injection temperature and lower injection speed. Scanning electron microscope (SEM) images and the distribution of surface layer electrical resistivity, clearly showed a notable influence by surface layer microstructures on the electrical resistivity, and the injection conditions affected both the value of the maximum electrical resistivity and the position where it occurred. This study offers an alternative green and simple molding process to prepare conductive PC nanocomposites and to achieve the industrialization of PC/CNT nanocomposite products which can be used in electromagnetic shielding and anti‐static fields. POLYM. COMPOS., 37:3245–3255, 2016. © 2015 Society of Plastics Engineers
Effect of the molecular chains grafted on graphene nanosheets on the properties of poly(l‐lactic acid) nanocomposites
Authors: Chen Lei , Li Xianhua , Wang Liyuan , Wang Wei , Xu Zhiwei
Published: May 2015

We prepared thermally reduced graphene oxide (TRG) grafted with polymethyl methacrylate (PMMA) and polyvinyl acetate (PVAc) (TRG‐g‐PMMA and TRG‐g‐PVAc) by γ‐ray irradiation‐induced graft polymerization and studied their effects on poly(l‐lactic acid) (PLLA) nanocomposites. PMMA and PVAc chains were proved to be grafted on the TRG surface successfully. TRG‐g‐PMMA and TRG‐g‐PVAc was found to restrict the crystallization behavior of PLLA compared with TRG. Moreover, tensile‐test results showed that TRG‐g‐PMMA and TRG‐g‐PVAc could enhance the elongation at break of PLLA nanocomposites without reducing the tensile strength and modulus compared with TRG, which indicated that the grafting of PMMA and PVAc chains on TRG could improve the toughness of PLLA nanocomposites. POLYM. COMPOS., 38:5–12, 2017. © 2015 Society of Plastics Engineers
On the analysis of force during secondary processing of natural fiber‐reinforced composite laminates
Authors: Debnath Kishore , Singh Inderdeep , Dvivedi Akshay
Published: May 2015

The rising concern regarding global warming has ignited a quest in the research fraternity towards development of sustainable materials that can reduce the carbon footprint. Natural fiber reinforced composites have made an excellent impression in the area of sustainable development because of their environmental and ecological aspects. These materials are widely used for manufacturing of engineering products. But, the use of natural fiber composites for engineering applications necessitates making of holes in order to ascertain assembly of several components by means of mechanical fastening. In this research endeavor, the drilling behavior of nettle/polypropylene (PP) composites has been experimentally investigated. The relative significance of the input process variables has also been studied with the help of statistical technique called analysis of variance (ANOVA). The present study established few significant facts in context of drilling of natural fiber reinforced composites. It has been observed that the facts established for drilling of synthetic fiber reinforced thermoset composites cannot be directly applied for natural fiber reinforced composites. POLYM. COMPOS., 38:164–174, 2017. © 2015 Society of Plastics Engineers
Thermal, static, and dynamic mechanical properties of bark cloth (ficus brachypoda) laminar epoxy composites
Authors: Rwawiire Samson , Tomkova Blanka
Published: May 2015

Bark cloth is a natural nonwoven fibrous fabric produced in Uganda from three species of trees: Ficus natalensis, Ficus brachypoda, and Antiaris toxicaria. The recently developed bark cloth composites has created a new class of textile composites which can find applications in interior automotive panels. Four bark cloth plies were utilized, the resin was infused using Vacuum Assisted Resin Transfer Molding (VARTM). Scanning Electron Microscopy was used to study the fabric's fiber morphology, surface functional groups were characterized using Fourier Transform Infrared. Overall, the static and the Dynamical mechanical analysis showed that the developed composites had a tensile strength ranging from 22 to 29 MPa whereas the flexural strength ranging from 45 to 100 MPa. The glass transition temperature of the composites was ranging from 53°C to 63°C. POLYM. COMPOS., 38:199–204, 2017. © 2015 Society of Plastics Engineers
Three‐dimensional crystalline supramolecular nanostructures from self‐assembly of rod–coil molecules incorporating lateral carboxyl group in the middle of the rod segment
Authors: Yu Shengsheng , Yang Yuntian , Li Chengfan , Chen Tie , Jin Long Yi
Published: May 2015

We report the synthesis and self‐assembling behaviour of coil–rod–coil molecules 1a–1c and 2a–2c, which incorporate lateral carboxyl or ester groups in the middle of the rod segment. The self‐assembling behaviour of these molecules was investigated in the bulk using differential scanning calorimetry, polarised optical microscopy and small‐angle X‐ray scattering. Our results reveal that hydrogen bonds strongly influence the self‐assembling behaviour of rod‐like building blocks. Molecules 1a–1c, which incorporate carboxyl groups in the middle of rod segments, self‐assemble into two‐dimensional (2‐D) columnar, three‐dimensional (3‐D) body‐centred tetragonal and 3‐D hexagonal close‐packed assemblies in the crystalline state. However, molecules 2a–2c, which contain ester groups in the centre of rod segments, self‐assemble into unexpected lamellar, hexagonal perforated lamellar and 2‐D columnar nanostructures in the bulk, indicating that hydrogen bonds impede intermolecular stacking in this rod–coil system. © 2015 Society of Chemical Industry
Temperature and pH responsive hydrogels based on polyethylene glycol analogues and poly(methacrylic acid) via click chemistry
Authors: Sheng Weijuan , Liu Teng , Liu Shouxin , Wang Qinqin , Li Xuan , Guang Naer
Published: May 2015

A novel temperature responsive copolymer, poly[2‐(2‐methoxyethoxy)ethyl methacrylate‐co‐oligo(ethylene glycol)methacrylate‐co‐N‐hydroxymethyl acrylamide] [P(MEO2MA‐co‐OEGMA‐co‐HMAM)], was synthesized by atom transfer radical polymerization. pH responsive poly(methacrylic acid) (PMAA) was synthesized by reversible addition‐fragmentation chain transfer polymerization. After the hydroxyl groups on P(MEO2MA‐co‐OEGMA‐co‐HMAM) were transformed into azide groups and the carboxyl groups on PMAA were transformed into alkyne groups respectively, a novel temperature and pH responsive hydrogel was fabricated by click chemistry between the azide‐P(MEO2MA‐co‐OEGMA‐co‐HMAM) and alkyne‐PMAA in the presence of CuSO4 and sodium ascorbate in aqueous solution. The rheological kinetics of gel formation demonstrated that gelation had commenced within 5 min at 25 °C, since then the storage modulus (G′) was higher than the loss modulus (G″). SEM images of hydrogel morphology and the swelling ratios of hydrogel at different temperatures and pH proved that the formed hydrogel had temperature and pH sensitivities. Bovine serum albumin was used as a model to evaluate the sustained release of the hydrogel; the results indicated that the hydrogel was a promising candidate for controlling protein drug delivery. © 2015 Society of Chemical Industry
Synthesis and phase behavior of a polynorbornene‐based molecular brush with dual “jacketing” effects
Authors: Qiao Yangyang , Ping Jing , Tian Haijian , Zhang Qikai , Zhou Sheng , Shen Zhihao , Zheng Shijun , Fan Xinghe
Published: May 2015

In this study, a series of well‐defined liquid crystalline molecular brushes with dual “jacketing” effects, polynorbornene‐g‐poly{2,5‐bis[(4‐methoxyhenyl)oxycarbonyl] styrene} (PNb‐g‐PMPCS), were synthesized by the “grafting through” method from ring opening metathesis polymerization of α‐norbornenyl‐terminated PMPCS. The rigid PMPCS side chain was synthesized by Cu(I)‐catalyzed atom transfer radical polymerization initiated by N‐[(2‐bromo‐2‐methylpropanoyl)ethyl]‐cis‐5‐norbornene‐exo‐2,3‐dicarboximide. The chemical structures of the molecular brushes were confirmed by 1H NMR and gel permeation chromatography (GPC), and the thermal properties were studied by thermogravimetric analysis (TGA). GPC results reveal that the molecular brushes have relatively narrow polydispersities. TGA results show that the molecular brushes have excellent thermal stabilities. The PMPCS side chains in all the molecular brushes form the columnar nematic liquid crystalline phase, which is a little different from the behavior of linear PMPCS possibly due to the confinement or other effects of the brush architecture which leads to decreased order. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2116–2123
The automatic experimental design for modeling the reaction mechanisms of chemical vapor deposition processes
Authors: Takahashi Takahiro , Ema Yoshinori
Published: May 2015

The identification of an appropriate reaction model (reaction mechanism) that indicates the reaction paths from source gases to films is one of the most important facets for developing chemical vapor deposition (CVD) processes. Previously, we developed a system that automatically identifies the kinetic models of reaction mechanisms involved in experimental results by the CVD processes using genetic algorithms (GAs). However, in order to automate the entire process of CVD development, it is necessary to automate the other processes associated with the reaction‐modeling process. Therefore, in this study, we proposed the method to automate the experimental design to determine more appropriate the reaction models. In addition, we developed the automatic system to design the experiments for the models. We demonstrated the feasibility and validity of the method using a simplified and synthetic CVD process. The system automatically and appropriately designed the experiments from the information of the reaction model candidates without using the knowledge of reaction engineering directly. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A calculation method of deposition profiles in chemical vapor deposition reactors using bio‐inspired algorithms
Authors: Takahashi Takahiro , Inagaki Taeka , Nariai Shingo , Kodama Junichi , Arakawa Masamoto , Ema Yoshinori
Published: May 2015

Estimating the predicted results of experimental data by a simulator is one of the most important processes in deciding the performance of the automatic modeling system of reaction mechanisms in chemical vapor deposition (CVD). Therefore, we developed a novel calculation method, in which robust and accurate calculations along with reduced computing cost were achieved, to reproduce deposition profiles in the specific types of reactors. In order to improve the performance of the calculation method, we developed the method by use of the novel optimization algorithms, which are biologically inspired. We adopted real‐coded genetic algorithms (GAs) and artificial bee colony (ABC) as the bio‐inspired algorithms (BIAs). Boundary value problems for estimating diffusion‐reaction equations by iterations of numerical integrations were changed into problems of finding the linear combinations consisted of a few “basis functions”, which are ideally inherent in the reactors. The coefficients of the linear combinations were optimized by the BIAs. We demonstrate the improved performance of the simulator by the BIAs using the batch‐type reactor with round‐shaped substrates. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Linear instability of constant PV cold‐core eddies in a two‐layer ocean
Authors: Cohen Yair , Dvorkin Yona , Paldor Nathan
Published: May 2015

The linear instability of a constant potential vorticity cold‐core eddy is studied in a two‐layer shallow water model. The basic state consists of the nonlinear gradient balance with uniform potential vorticity, and in a cold‐core eddy these two relations have no analytic solution. Numerical solutions of the basic state structure provide a functional relation between the maximum tangential velocity and the ratio of the eddy's maximal depth and its radius. The maximal growth rates of small amplitude wavelike disturbances are found numerically by employing the shooting to fitting point method, applied in a way that guarantees the regularity of the solutions at the singular points: infinity, eddy centre and the radius where the interface outcrops. Our results show that wave‐numbers 2, 3 and 4 are unstable with growth rates of the order of 1 day at small ocean depth and that the growth rates decay with the ocean depth. The instabilities result from the interaction between a lower‐layer Rossby wave and an upper‐layer Frontal wave. An energy equation for the perturbations shows that the decay of the growth rates with the increase in ocean depth results from the decay of both the Reynolds Stress in the upper layer and the baroclinic energy conversion between the two layers. The decay of the Reynolds Stress with ocean depth was not found in studies of ocean currents which explains the fact that eddies become stable in a 1‐layer model while currents can be unstable at large ocean depth. Comparison with long‐lived eddies in the ocean suggests that the current model should be made more realistic before it can be applied to observed eddies.
Detecting pleiotropy in Mendelian randomisation studies with summary data and a continuous outcome
Authors: Greco M Fabiola Del , Minelli Cosetta , Sheehan Nuala A , Thompson John R
Published: May 2015

Mendelian randomisation (MR) estimates causal effects of modifiable phenotypes on an outcome by using genetic variants as instrumental variables, but its validity relies on the assumption of no pleiotropy, that is, genes influence the outcome only through the given phenotype. Excluding pleiotropy is difficult, but the use of multiple instruments can indirectly address the issue: if all genes represent valid instruments, their MR estimates should vary only by chance. The Sargan test detects pleiotropy when individual phenotype, outcome and genotype data are measured in the same subjects. We propose an alternative approach to be used when only summary genetic data are available or data on gene‐phenotype and gene‐outcome come from different subjects. The presence of pleiotropy is investigated using the between‐instrument heterogeneity Q test (together with the I2 index) in a meta‐analysis of MR Wald estimates, derived separately from each instrument. For a continuous outcome, we evaluate the approach through simulations and illustrate it using published data. For the scenario where all data come from the same subjects, we compare it with the Sargan test. The Q test tends to be conservative in small samples. Its power increases with the degree of pleiotropy and the sample size, as does the precision of the I2 index, in which case results are similar to those of the Sargan test. In MR studies with large sample sizes based on summary data, the between‐instrument Q test represents a useful tool to explore the presence of heterogeneity due to pleiotropy or other causes. Copyright © 2015 John Wiley & Sons, Ltd.
Adaptive sampling in two‐phase designs: a biomarker study for progression in arthritis
Authors: McIsaac Michael A. , Cook Richard J.
Published: May 2015

Response‐dependent two‐phase designs are used increasingly often in epidemiological studies to ensure sampling strategies offer good statistical efficiency while working within resource constraints. Optimal response‐dependent two‐phase designs are difficult to implement, however, as they require specification of unknown parameters. We propose adaptive two‐phase designs that exploit information from an internal pilot study to approximate the optimal sampling scheme for an analysis based on mean score estimating equations. The frequency properties of estimators arising from this design are assessed through simulation, and they are shown to be similar to those from optimal designs. The design procedure is then illustrated through application to a motivating biomarker study in an ongoing rheumatology research program. Copyright © 2015 © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.
Mechanische Hochtemperatureigenschaften von Stahlzuggliedern aus kaltverformtem Blankstahl der Festigkeitsklasse S355
Authors: Häßler Dustin , Hothan Sascha
Published: May 2015

Im Bauwesen werden für Zugglieder häufig Kreisvollprofile mit relativ kleinen Durchmessern eingesetzt. Diese Bauteile bestehen in der Regel aus gezogenem, kaltverformtem Blankstahl. Aufgrund des Herstellungsverfahrens kommt es zu einer Veränderung der Materialeigenschaften des Stahls. Für Blankstahl sind in der Norm [1] keine temperaturabhängigen Materialkennwerte angegeben. An der BAM Bundesanstalt für Materialforschung und ‐prüfung wurden im Rahmen eines Forschungsvorhabens [2] die mechanischen Hochtemperatureigenschaften von Stahlzuggliedern aus kaltverformtem Blankstahl der Festigkeitsklasse S355 untersucht. Als Ausgangsmaterial wurde ein Kreisvollprofil mit einem Durchmesser von 20 mm verwendet. Für den Blankstahl wurden die chemische Zusammensetzung, der Elastizitätsmodul, die Spannungs‐Dehnungs‐Kennlinien sowie der Wärmeausdehnungskoeffizient bestimmt. Ziel der Untersuchungen war es herauszufinden, welche materialspezifischen Besonderheiten kaltverformter Blankstahl unter Brandeinwirkung gegenüber anderen Stählen besitzt und inwieweit sich die in der Norm [1] für warmgewalzten Baustahl angegebenen Werte auf Blankstahl übertragen lassen. Die Ergebnisse der Materialuntersuchungen werden zudem für die numerische Nachrechnung von Brandversuchen an Stahlzuggliedern mit reaktiver Brandschutzbeschichtung verwendet.

Mechanical properties of cold drawn steel S355 at elevated temperatures used for tension rods. In construction, circular solid steel rods with relatively small diameter are often used for tensile elements. These elements are usually made of cold drawn steel. As a result of the manufacturing process, the material properties of the steel are changed. In the standard [1], no information regarding the temperature‐dependant material properties of cold drawn steel are given. At BAM Federal Institute for Materials Research and Testing, a research project [2] was conducted to investigate the mechanical properties at elevated temperatures of tension elements made of cold drawn steel type S355. In the experiments, the tensile specimens were produced from a circular solid profile with a diameter of 20 mm. Within the research project, the chemical composition, the modulus of elasticity, the stress‐strain‐relationships and the thermal expansion coefficient were determined. The aim of this investigation was to identify the specific material characteristics of cold drawn steel under fire exposure. Furthermore, a comparison between cold drawn steel and the commonly used in construction hot‐rolled steel was done, in order to clarify whether the material properties of hot rolled steel that are given in the standard [1] can be also used for cold drawn steel. The results of the material tests are used as input values for a numerical simulation of fire tests on tension elements with reactive fire protection systems.
Frei Otto – leichte Dächer für eine moderne Welt
Authors: Möller Eberhard
Published: May 2015

Mit seinen Vorschlägen und Bauten hat Frei Otto der Welt ein Universum an Ideen geschenkt, das seines gleichen sucht. Er ist der große Pionier des Leichtbaus im 20. Jahrhundert. Aufgrund seiner außergewöhnlichen Leistungen in Natur‐ und Grundlagenforschung, in Wissenschaft und Lehre, in Architektur und konstruktivem Ingenieurbau, in Kultur und Technik steht er in einer Reihe mit Persönlichkeiten wie Félix Candela, Pier Luigi Nervi, Antoni Gaudí oder Gustave Eiffel. Am 15. Mai 2015 wird ihm nun posthum in Miami Beach, USA, der Pritzker‐Architektur‐Preis verliehen, häufig als Nobel‐Preis der Architektur bezeichnet.

Frei Otto – Lightweight roofs for a modern world. With his suggestions and buildings Frei Otto presented the world a universe of ideas that has no equal. He is the great pioneer of lightweight structures in the 20th century. Due to its remarkable achievements in natural and fundamental research, in science and education, in architecture and structural engineering, in culture and technology, he joins the ranks of such internationally‐renowned public characters as Félix Candela, Pier Luigi Nervi, Antoni Gaudí and Gustave Eiffel. On May 15th 2015 he posthumously is awarded the Pritzker Architecture Prize in Miami Beach, USA, often referred to as Nobel Prize of Architecture.
Bauwesen an der Ruhr‐Universität Bochum im Jubiläumsjahr – ein Rückblick
Authors: Mark Peter
Published: May 2015

Eine junge Universität wird 50 – die Ruhr‐Universität in Bochum. Grund genug auch auf die dortige Fakultät für Bau‐ und Umweltingenieurwissenschaften zurückzuschauen, die sich 1973 – wenige Jahre nach der Universitätsgründung – aus ihrer “Keimzelle“, dem Institut für Konstruktiven Ingenieurbau, bildete. Der Beitrag stellt besondere Aspekte der bewegten und erfolgreichen Historie vor mit ihren prägenden Persönlichkeiten hin zur heutigen Fakultätsstruktur und Forschungsausrichtung.

Civil Engineering at the Ruhr‐Universität Bochum in the year of anniversary – a review. A young university celebrates its 50th anniversary – the Ruhr‐Universität in Bochum. Reason enough to review the history of the Faculty of Civil and Environmental Engineering, a university’s offspring in 1973 from the Department of Structural Engineering. Insight into its eventful and successful history is provided presenting its significant personalities as well as the nowadays constitution and main fields of research.
Storytelling for Fluency and Flair
Authors: Campbell Terry , Hlusek Michelle
Published: May 2015

In the classroom experiences described in this article, grade three students were introduced to storytelling through the interactive read aloud of a mentor text and a storytelling demonstration, followed by daily collaborative activities involving listening, speaking, reading, and writing, culminating in dramatic storytelling performances. The article details a sample instructional sequence used for one week during the daily literacy block, explores how reading and speaking fluency improved, and how deeper story comprehension developed through the processes of talking about the stories, and rehearsing and telling stories for performance. In addition, the collaborative approach to preparing and presenting stories provided a context for strong peer support – socially, emotionally, and academically.
Does Schooling Affect Women’s Desired Fertility? Evidence From Malawi, Uganda, and Ethiopia
Authors: Behrman Julia Andrea
Published: May 2015

Demographic scholarship suggests that schooling plays an important role in transforming fertility preferences in the early stages of fertility decline. However, there is limited evidence on the relationship between schooling and fertility preferences that addresses the endogeneity of schooling. I use the implementation of Universal Primary Education (UPE) policies in Malawi, Uganda, and Ethiopia in the mid-1990s to conduct a fuzzy regression discontinuity analysis of the effect of schooling on women’s desired fertility. Findings indicate that increased schooling reduced women’s ideal family size and very high desired fertility across all three countries. Additional analyses of potential pathways through which schooling could have affected desired fertility suggest some pathways—such as increasing partner’s education—were common across contexts, whereas other pathways were country-specific. This analysis contributes to demographic understandings of the factors influencing individual-level fertility behaviors and thus aggregate-level fertility decline in sub-Saharan Africa.
Hippocampus and basal forebrain volumes modulate effects of anticholinergic treatment on delayed recall in healthy older adults
Authors: Teipel Stefan J. , Bruno Davide , Grothe Michel J. , Nierenberg Jay , Pomara Nunzio
Published: May 2015

Introduction

Volumes of hippocampus and cholinergic basal forebrain are associated with delayed recall performance and may modulate the effect of a muscarinic receptor antagonist on delayed recall in healthy volunteers.

Methods

We studied 15 older adults before and after the oral administration of a single dose of 1 or 2 mg of the preferential M1 muscarinic receptor antagonist trihexyphenidyl (Artane™) or placebo in a double‐blind randomized cross‐over design. Hippocampus and basal forebrain volumes were measured using magnetic resonance imaging.

Results

We found a significant interaction between treatment and hippocampus volume and a trend level effect between treatment and anterior basal forebrain volume on task performance, with an attenuation of the association between volume size and performance with trihexyphenidyl.

Discussion

These findings suggest a reduction of delayed recall performance with increasing doses of the muscarinic antagonist that is related to an uncoupling of the association of task performance with cholinergic basal forebrain and hippocampus volumes.
Clec4g (LSECtin) interacts with BACE1 and suppresses Aβ generation
Authors: Kizuka Yasuhiko , Kitazume Shinobu , Sato Keiko , Taniguchi Naoyuki
Published: May 2015

β‐Site amyloid precursor protein cleaving enzyme‐1 (BACE1) is a central molecule in Alzheimer's disease (AD). It cleaves amyloid precursor protein (APP) to produce the toxic amyloid‐β (Aβ) peptides. Thus, a novel BACE1 modulator could offer a new therapeutic strategy for AD. We report that C‐type lectin‐like domain family 4, member g (Clec4g, also designated as LSECtin) interacts with BACE1 in mouse brain and cultured cells. Overexpression of Clec4g suppressed BACE1‐mediated Aβ generation, and affected the intracellular distribution of BACE1 but not its catalytic activity. These results highlight a novel role of Clec4g in negatively regulating BACE1 function.
Crystal structure of human nicotinic acid phosphoribosyltransferase
Authors: Marletta Ada Serena , Massarotti Alberto , Orsomando Giuseppe , Magni Giulio , Rizzi Menico , Garavaglia Silvia
Published: May 2015

Nicotinic acid phosphoribosyltransferase (EC 2.4.2.11) (NaPRTase) is the rate‐limiting enzyme in the three‐step Preiss–Handler pathway for the biosynthesis of NAD. The enzyme catalyzes the conversion of nicotinic acid (Na) and 5‐phosphoribosyl‐1‐pyrophosphate (PRPP) to nicotinic acid mononucleotide (NaMN) and pyrophosphate (PPi). Several studies have underlined the importance of NaPRTase for NAD homeostasis in mammals, but no crystallographic data are available for this enzyme from higher eukaryotes. Here, we report the crystal structure of human NaPRTase that was solved by molecular replacement at a resolution of 2.9 Å in its ligand‐free form. Our structural data allow the assignment of human NaPRTase to the type II phosphoribosyltransferase subfamily and reveal that the enzyme consists of two domains and functions as a dimer with the active site located at the interface of the monomers. The substrate‐binding mode was analyzed by molecular docking simulation and provides hints into the catalytic mechanism. Moreover, structural comparison of human NaPRTase with the other two human type II phosphoribosyltransferases involved in NAD biosynthesis, quinolinate phosphoribosyltransferase and nicotinamide phosphoribosyltransferase, reveals that while the three enzymes share a conserved overall structure, a few distinctive structural traits can be identified. In particular, we show that NaPRTase lacks a tunnel that, in nicotinamide phosphoribosiltransferase, represents the binding site of its potent and selective inhibitor FK866, currently used in clinical trials as an antitumoral agent.