bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of periodic copolymers via ring‐opening copolymerizations of cyclic anhydrides with tetrahydrofuran using nonafluorobutanesulfonimide as an organic catalyst and subsequent transformation to aliphatic polyesters
Authors: Tang Tang , Oshimura Miyuki , Yamada Shinji , Takasu Akinori , Yang Xiaoping , Cai Qing
Published: May 2012

To synthesize polyesters and periodic copolymers catalyzed by nonafluorobutanesulfonimide (Nf2NH), we performed ring‐opening copolymerizations of cyclic anhydrides with tetrahydrofuran (THF) at 50–120 °C. At high temperature (100–120 °C), the cyclic anhydrides, such as succinic anhydride (SAn), glutaric anhydride (GAn), phthalic anhydride (PAn), maleic anhydride (MAn), and citraconic anhydride (CAn), copolymerized with THF via ring‐opening to produce polyesters (Mn = 0.8–6.8 × 103, Mn/Mw = 2.03–3.51). Ether units were temporarily formed during this copolymerization and subsequently, the ether units were transformed into esters by chain transfer reaction, thus giving the corresponding polyester. On the other hand, at low temperature (25–50 °C), ring‐opening copolymerizations of the cyclic anhydrides with THF produced poly(ester‐ether) (Mn = 3.4–12.1 × 103, Mw/Mn = 1.44–2.10). NMR and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectra revealed that when toluene (4 M) was used as a solvent, GAn reacted with THF (unit ratio: 1:2) to produce periodic copolymers (Mn = 5.9 × 103, Mw/Mn = 2.10). We have also performed model reactions to delineate the mechanism by which periodic copolymers containing both ester and ether units were transformed into polyesters by raising the reaction temperature to 120 °C. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Successful treatment of idiopathic pulmonary capillaritis with intravenous cyclophosphamide
Authors: Flanagan Frances , Glackin Louisa , Slattery Dubhfeasa M.
Published: May 2012

Idiopathic pulmonary hemosiderosis (IPH), a subtype of diffuse alveolar hemorrhage is a rare condition, first described by Virchow in 1864. Historically, it manifests in children in the first decade of life with the combination of hemoptysis, iron deficiency anemia, and alveolar infiltrates on chest radiograph. More recently, diffuse alveolar hemorrhage has been classified by the absence or presence of pulmonary capillaritis (PC), the latter carrying a potential for a poorer outcome. While systemic corticosteroids remain the first line treatment option, other immune modulators have been trailed including hydroxychloroquine, azathioprine, 6‐mercaptopurine, and cyclophosphamide with varying results. Our case demonstrates for the first time, the successful use of intravenous cyclophosphamide in the management of chronic idiopathic PC. Pediatr Pulmonol. 2013; 48:303–305. © 2012 Wiley Periodicals, Inc.
Mechanism of zinc‐mediated inhibition of caspase‐9
Authors: Huber Kristen L. , Hardy Jeanne A.
Published: May 2012

Zinc‐mediated inhibition is implicated in global caspase regulation, with relief of zinc‐mediated inhibition central to both small‐molecule and natively induced caspase activation. As an initiator, caspase‐9 regulates the upstream stages of the apoptotic caspase cascade, making it a critical control point. Here we identify two distinct zinc‐binding sites on caspase‐9. The first site, composed of H237, C239, and C287, includes the active site dyad and is primarily responsible for zinc‐mediated inhibition. The second binding site at C272 is distal from the active site. Given the amino‐acid conservation in both regions, these sites appear to be present across the caspase family underscoring the importance of zinc‐mediated regulation of this class of enzymes.
Smeared quantum lattices exhibiting 𝒫𝒯‐symmetry with positive 𝒫
Authors: Znojil M. , Geyer H.B.
Published: May 2012

A new strategy of the use of 𝒫𝒯 symmetry in quantum theory is proposed. The essence of the innovation lies in the replacement of the usual parity‐like choice of 𝒫 by its non‐involutory and positive‐definite alternative 𝒫(positive) ≠ I. The resulting modified concept of 𝒫(positive)𝒯‐symmetry remains phenomenologically appealing as well as technically useful. This is demonstrated and illustrated via an N‐site quantum lattice model which is exactly solvable in terms of Legendre polynomials.
Duality orbits of non‐geometric fluxes
Authors: Dibitetto G. , Fernández‐Melgarejo J.J. , Marqués D. , Roest D.
Published: May 2012

Compactifications in duality covariant constructions such as generalised geometry and double field theory have proven to be suitable frameworks to reproduce gauged supergravities containing non‐geometric fluxes. However, it is a priori unclear whether these approaches only provide a reformulation of old results, or also contain new physics. To address this question, we classify the T‐ and U‐duality orbits of gaugings of (half‐)maximal supergravities in dimensions seven and higher. It turns out that all orbits have a geometric supergravity origin in the maximal case, while there are non‐geometric orbits in the half‐maximal case. We show how the latter are obtained from compactifications of double field theory.
The physics behind free electron lasers (FELs) based on magnetostatic and optical undulators
Authors: Ribič Primož Rebernik , Margaritondo Giorgio
Published: May 2012

By explicitly writing the equations of motion for highly relativistic electrons in an electromagnetic field we show the equivalence between the magnetostatic and optical (laser) undulator‐based free electron lasers (FELs). In order to gain insight into the physics behind both FEL mechanisms we use a simplified approach developed in Ref. 1 to describe the optical amplification process. By using elementary physics we explain the phenomenon of microbunching, caused by the interaction of electrons with the emitted wave, which leads to coherent emission of radiation and is the essential ingredient in the lasing effect of a FEL. With our simplified model we derive the two main FEL parameters – the gain and saturation lengths. Finally, we discuss the potential advantages of using an optical instead of a magnetostatic undulator in a FEL. With our approach the physics behind FELs becomes evident and accessible to researchers outside the specialized field.
Lead adsorption on the pseudo‐10‐fold surface of the Al13Co4 complex metallic alloy: A first principle study
Authors: Villaseca S. Alarcón , Dubois J.‐M. , Gaudry É.
Published: May 2012

A first principle study of lead adsorption on the pseudo‐10‐fold surface of the orthorhombic Al13Co4 intermetallic compound has been performed using four possible structural models as substrate. Coverage between atomic adsorption to near 0.08 atm./Å2 has been considered. Relative adsorption energies of Pb atoms on different surface sites in addition with simulated scanning tunneling microscopy images were obtained for each model. Our ab initio calculations demonstrate that the experimental results published recently, highlighting (i) the presence of a preferential adsorption site and (ii) the formation of Pb rows extending along the [010] direction [N. J. Phys. 2011, 13, 10301114] can be only reproduced using a dense Al‐rich termination as the substrate structural model. This result confirms the previously established structural model for the (100) surface of orthorhombic Al13Co4 [Phys. Rev. B 2011, 84, 085411]. This study then provides an understanding of the experimental observations for the different lead coverages. © 2012 Wiley Periodicals, Inc.
Computer virus propagation model based on bounded rationality evolutionary game theory
Authors: Jin Cong , Jin Shu‐Wei , Tan Hua‐Yong
Published: May 2012

Increasing spread of computer viruses has caused huge economic losses and psychological influence on people's lives, so building an effective computer virus propagation model to predict the propagation of viruses is necessary. Classical computer virus propagation models can predict the propagation tendency of computer viruses, but they cannot accurately quantify the loss of the user because of these models only were considered from the view of the node connection rate and did not consider the various factors of the participators oneself. In this paper, under the conditions of bounded rationality, the evolutionary game theory is used for building computer virus propagation model. By referencing “replication dynamic” thought, the long‐term evolutionary trend of the normal competitive game between normal users and potential attacks using the evolution strategy can be described. According to the Liapunov theorem, the equilibrium and stability of the proposed model are also discussed. Finally, by simulation analysis, we determine the impact of some important parameters of the proposed model for virus propagation. Simulation results show that the proposed model can provide theoretical support for predicting computer virus propagation. Copyright © 2012 John Wiley & Sons, Ltd.
Testing and verification in service‐oriented architecture: a survey
Authors: Bozkurt Mustafa , Harman Mark , Hassoun Youssef
Published: May 2012

Service‐oriented architecture (SOA) is gaining momentum as an emerging distributed system architecture for business‐to‐business collaborations. This momentum can be observed in both industry and academic research. SOA presents new challenges and opportunities for testing and verification, leading to an upsurge in research. This paper surveys the previous work undertaken on testing and verification of service‐centric systems, which in total are 177 papers, showing the strengths and weaknesses of current strategies and testing tools and identifying issues for future work. Copyright © 2012 John Wiley & Sons, Ltd.
Voltage distribution analysis and grading ring design for porcelain insulators on 750‐kV compact transmission lines
Authors: Xie Tianxi , Peng Zongren
Published: May 2012

On a compact transmission line, there are three phases arranged in one tower window. They form an inverted triangle with a small air gap, having no shielding between each other. This characteristic results in mutual effects among the three phases, which cause higher voltages and electric field intensities on the porcelain insulators and fittings than the ordinary lines. In this paper, a three‐dimensional finite element method (FEM) is presented to calculate the potential and electric field distributions of the porcelain insulators on a 750‐kV compact double‐circuit transmission line. Considering the mutual effects among the three phases, the structural parameters of the grading ring are optimized to reduce the voltages and electric field intensities on the insulators. The results show that the significant mutual effects among the three phases need to be taken into account in the design and testing of the insulators and fittings. In addition, structural parameters of the optimized grading ring are proposed on the basis of the above‐mentioned analysis. The comparison between the numerical calculations and the test results shows the accuracy of the FEM. Thus, in the approval test, it might be more reasonable and efficient to determine the correction factors through analyzing the calculations of the actual line and test arrangement. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Stabilizing switching control for nonlinear system based on quasi‐ARX RBFN model
Authors: Wang Lan , Cheng Yu , Hu Jinglu
Published: May 2012

In this paper, a fuzzy switching adaptive control approach is presented for nonlinear systems. The proposed fuzzy switching adaptive control law is composed of a quasi‐ARX radial basis function network (RBFN) prediction model and a fuzzy switching mechanism. The quasi‐ARX RBFN prediction model consists of two parts: a linear part used for a linear controller to ensure boundedness of the input and output signals; and an RBFN nonlinear part used to improve control accuracy. By using the fuzzy switching scheme between the linear and nonlinear controllers to replace the 0/1 switching, it can realize a better balance between stability and accuracy. Theoretical analysis and simulation results show the effectiveness of the proposed control method on the stability, accuracy, and robustness. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Fast computation of Q‐value‐based dynamic programming on road networks
Authors: Wen Feng , Zhang Deng , Mabu Shingo , Mainali Manoj Kanta , Hirasawa Kotaro
Published: May 2012

One of the essential components of vehicle navigation systems is route planning. The single shortest path problem and multiple shortest path problem have been widely studied for route planning. This paper introduces a Q‐value‐based dynamic programming using the division concept for solving both single and multiple shortest path problems on road networks. The proposed algorithm divides the whole network into different divisions, and the updating of Q values in each division is one stage for searching the optimal routes on road networks. The proposed algorithm can greatly save the computational time without any preprocessing on the road networks. The proposed algorithm is also systematically studied in various sizes of road networks. The simulation results show the efficiency and effectiveness of the proposed algorithm on large‐scale road networks. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Surface modifications of aligned carbon nanotube thin films by Argon‐ion sputtering
Authors: Izumida Fukunori , Ye Rongbin , Ohta Koji , Baba Mamoru , Kusunoki Michiko
Published: May 2012

To use carbon nanotubes (CNTs) as anode material for the solid‐state thin‐film Li‐ion rechargeable battery, the tubes are preferred to be aligned perpendicular to a substrate and the CNT thin film to have a smooth surface. Using an Ar‐ion sputtering technique, we carried out the surface modifications of the CNT thin film prepared by the SiC surface decomposition method. In order to evaluate the surface modification, the surface and cross section of the modified CNT film were investigated by field‐emission scanning electron microscopy and atomic force microscopy. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A green battery by pot‐plant power
Authors: Yamaguchi Tomoyuki , Hashimoto Shuji
Published: May 2012

When a metal electrode is inserted into a part of a plant, and another metal electrode is placed in the soil, an electrical potential difference is generated between the two electrodes. The plant has a lower potential than the soil. The generated voltage from the electrical potential difference between one plant and the adjacent soil is small (several hundred millivolts), and the current is extremely low (several hundred nanoamperes). However, in order to boot up some electrical circuits, the voltage and current need to be in the volt and microampere order, respectively. If the electrical potential difference between one plant and the soil is used as a power supply, it is necessary to develop a nanoscale electrical device that can work with extremely low wattage. Here we report a novel green battery composed of 10 pot plants by serial–parallel connections. The developed battery could generate almost 3 V and 3 µA to drive electric devices. We designed an LED blinking circuit composed of discrete semiconductor parts, which was driven by the generated plant power, and confirmed its performance through the experiments. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Study of weather and location effects on wind turbine failure rates
Authors: Tavner P.J. , Greenwood D. M. , Whittle M. W. G. , Gindele R. , Faulstich S. , Hahn B.
Published: May 2012

Understanding the availability of wind turbines (WT) is vital to maximize WT energy production and minimize the capital payback period. Previous work on this subject concentrated on reliability and the location of WT failure modes rather than root causes. This paper concentrates on the influence of weather and WT location on failure rate and downtime, to try to understand root causes and the consequences of failure. The paper goes further than a previous study, which used Windstats data from the whole of Denmark, by considering a limited population of identical WTs at three locations on the German Nordzee, Ostzee and in western Germany, using data from WMEP and local weather stations. This new study focuses more precisely than the previous study by using more reliable data. The data were analysed to find the WT failures and weather conditions and then cross‐correlate them. To confirm their representativeness, the reliability characteristics of these smaller WT populations followed the average trends of the overall WMEP survey. However, clear differences were observed in the failure behaviour of the WTs at the three locations. Annual periodicity was seen in the weather data, as expected, but not in individual WT population failure data. However, clear cross‐correlations can be seen between WT failures and weather data, in particular wind speed, maximum temperature and humidity. These cross‐correlations were more convincing than those found in the earlier, larger Danish study, vindicating the more focused approach. It is also clear from the analysis that Operation & Maintenance also has an impact on WT failure rates. These factors will be important for the operation of offshore WTs with the work indicating how weather conditions may affect offshore WT failure rates. Copyright © 2012 John Wiley & Sons, Ltd.
Roles of group I metabotropic glutamate receptors under physiological conditions and in neurodegeneration
Authors: Baudry Michel , Greget Renaud , Pernot Fabien , Bouteiller Jean‐Marie , Xiaoning Bi
Published: May 2012

Since their cloning in 1991, metabotropic glutamate receptors (mGluRs) have been the subject of numerous studies, as it rapidly became apparent that this class of G‐protein coupled receptors (GPCRs) participated in numerous functions in the central nervous system. Group I mGluR receptors function chiefly postsynaptically, as modulators of the ionotropic AMPA and NMDA glutamate receptors, and triggers of intracellular signaling pathways that could lead to long‐term modifications of synaptic efficacy and to neurodegeneration. It is now clear that the activation of group I mGluR receptors has only minimum effects on synaptic transmission and regulation at low level of presynaptic activity; in contrast, they become engaged and exert potent effects on intracellular cascades at high frequency of stimulation. Moreover, when postsynaptic calcium reaches levels sufficient to activate the calcium‐dependent protease calpain, calpain truncates the C‐terminal domain of mGluR1α and changes its signaling properties to make it exclusively neurodegenerative. A new method using the transmembrane transport properties of the tat‐peptide prevents neuronal degeneration following excessive activation of the NMDA receptors, which could occur in ischemia and various forms of excitotoxicity. Caution should be observed, however, regarding the numerous phenomena observed following the prolonged activation of group I mGluRs by exogenous agonists. WIREs Membr Transp Signal 2012, 1:523–532. doi: 10.1002/wmts.51

For further resources related to this article, please visit the WIREs website.

Conflict of interest: MB and JMB have a conflict of interest. The University of Southern California holds an equity interest in Rhenovia Pharma, and has also received licensing income from Rhenovia Pharma.
Desensitization and internalization mechanisms of the 5‐HT4 receptors
Authors: Mnie‐Filali Ouissame , Piñeyro Graciela
Published: May 2012

The serotonin 5‐HT4 receptor is a member of the superfamily of G‐protein‐coupled receptors (GPCRs) that mediates many physiological effects in the central nervous system and its periphery. Recently, a 5‐HT4 receptor agonist was shown to produce faster antidepressant‐like response in animal models in comparison to conventional antidepressants, and this effect persists for at least 2 weeks of treatment without generating tolerance. Importantly, long‐term administration of various classes of antidepressants has been reported to induce desensitization and/or downregulation of 5‐HT4 receptors in brain areas implicated in the physiopathology of depression. These observations point to the importance of studying the mechanisms of desensitization and regulation of the 5‐HT4 receptors since they seem distinctively implicated in therapeutic response to the classical selective serotonin reuptake inhibitors (SSRIs) and novel faster acting antidepressants. Hence, desensitization and internalization mechanisms of the 5‐HT4 receptors have been characterized with special emphasis on the 5‐HT4a and 5‐HT4b isoforms. WIREs Membr Transp Signal 2012, 1:779–788. doi: 10.1002/wmts.52

For further resources related to this article, please visit the WIREs website.
Combining accelerator and reactor measurements of θ
13: the first result
Authors: Machado P. A. N. , Minakata H. , Nunokawa H. , Funchal R. Zukanovich
Published: May 2012

Abstract

The lepton mixing angle θ
13, the only unknown angle in the standard three-flavor neutrino mixing scheme, is finally measured by the recent reactor and accelerator neutrino experiments. We perform a combined analysis of the data coming from T2K, MINOS, Double Chooz, Daya Bay and RENO experiments and find sin2 2θ
13 = 0.096 ± 0.013(±0.040) at 1 σ (3 σ) CL and that the hypothesis θ
13 = 0 is now rejected at a significance level of 7.7 σ. We also discuss the near future expectation on the precision of the θ
13 determination by using expected data from these ongoing experiments.
Liouville theory, $ \mathcal{N} = 2 $ gauge theories and accessory parameters
Authors: Ferrari Franco , Piatek Marcin
Published: May 2012

Abstract

The correspondence between the semiclassical limit of the DOZZ quantum Liouville theory and the Nekrasov-Shatashvili limit of the
$ \mathcal{N} = 2 $
(Ω-deformed) U(2) super-Yang-Mills theories is used to calculate the unknown accessory parameter of the Fuchsian uniformization of the 4-punctured sphere. The computation is based on the saddle point method. This allows to find an analytic expression for the N

f
= 4, U(2) instanton twisted superpotential and, in turn, to sum up the 4-point classical block. It is well known that the critical value of the Liouville action functional is the generating function of the accessory parameters. This statement and the factorization property of the 4-point action allow to express the unknown accessory parameter as the derivative of the 4-point classical block with respect to the modular parameter of the 4-punctured sphere. It has been found that this accessory parameter is related to the sum of all rescaled column lengths of the so-called ’critical’ Young diagram extremizing the instanton ’free energy’. It is shown that the sum over the ’critical’ column lengths can be rewritten in terms of a contour integral in which the integrand is built out of certain special functions closely related to the ordinary Gamma function.
Remote Sensing and GIS based Comparative Morphometric Study of Two Sub-watershed of Different Physiographic Conditions, West Godavari District, A.P.
Authors: Rao G. Tamma , Rao V. V. S. Gurunadha , Dakate Ratnakar , Rao S. T. Mallikharjuna , Rao B. M. Raja
Published: May 2012

In this present study, Remote Sensing (RS) and Geographical Information System (GIS) techniques were used to update drainage and surface water bodies and to evaluate linear, relief and aerial morphometric parameters of the two sub-watersheds viz. Jilugumilli and Regulapadu in the northern part of West Godavari District, Andhra Pradesh. The area of Jilugumilli and Regulapadu watersheds spread over about 110 & 80 sq. km respectively. The morphometric analysis of the drainage networks of Regulapadu and Jilugumilli sub-watersheds exhibit sub-dendritic and sub parallel drainage pattern. The variation in stream length ratio changes due to change in slope and topography. It was inferred from the study that the streams are in a mature stage in Regulapadu and Jilugumilli watersheds, which indicated the geomorphic development. The variations in bifurcation ratio values among the sub-watersheds are described with respect to topography and geometric development. The stream frequencies for both sub-watersheds exhibit positive correlation with the drainage density, indicating increase in stream population with respect to increase in drainage density. The Jilugumilli watershed has a coarse drainage texture and Regulapadu sub-watershed is a fine drainage texture in nature. In the present study an attempt has been made to analyse the morphometric analysis of two sub-watersheds under different physiographic conditions. Morphometric analysis is one of the essential analyses required for development and management of watershed.
Hydrogeomorphic Classification and Aquifer Disposition in the Markanda River Basin, Northwestern India – Hydrogeological Approach
Authors: Singh Kshetrimayum Krishnakanta , Bajpai Vishwa Nath
Published: May 2012

The regional hydrogeological aspects of the Markanda river basin in the Himalayan foothills, NW India have been attempted. The basin has been hydro-geomorphologically analyzed as ridge, piedmont zone, alluvial plain, flood plain and palaeochannel. Groundwater prospect in the alluvial plain, flood plain and palaeochannel areas were found to be promising. Water table contour maps of the basin revealed that groundwater flows from northeast to southwest. Groundwater permeability is low in the northern part and is high towards the southern part of the basin. The areas of recharge were identified in the northern part of the basin, while the areas of discharge were identified in the central and lower parts of the basin. Hydrogeologic transects across and along the basin indicate that aquifer horizons are made up of fine sand, medium sand and gravelly sand. These aquifer layers are laterally extensive but limited in thickness. They occur as multistoried sand bodies with pinch and swell behavior. The overall study gives an understanding of the present regional hydrogeological scenario of the Markanda basin. Such detailed integrated approach would help to locate productive groundwater areas before installing a new tubewell in the region. Also, it would help in planning future groundwater management of the region.
Safety Essentials: Acute Reactions to Iodinated Contrast Media
Authors: Iyer Ramesh S. , Schopp Jennifer G. , Swanson Jonathan O. , Thapa Mahesh M. , Phillips Grace S.
Published: May 2012

The objectives of this article are to review the diagnosis and management of acute nonrenal reactions to iodinated contrast media. We will begin by discussing the types of contrast media and their correlative rates of reaction. The mechanism of contrast reactions, predisposing risk factors, and preventative measures will then be discussed. The remainder of the article will review the assessment of potential reactions, initial management, and treatment algorithms for specific reactions.
Trends in Radiology Fellowship Training: A Canadian Review 2009-2011
Authors: Ryan John , Khandelwal Ashish , Fasih Najla
Published: May 2012

Purpose

To assess the percentage, type, and location of radiology fellowships chosen by graduating Canadian residents between 2009 and 2011.

Methods

A short e-mail questionnaire was sent to the radiology program directors at all 16 institutions in Canada that provide English or French residency. The responses were collected between December 6, 2010, and May 20, 2011.

Results

A 75% response rate was observed for the survey: 76%–79% residents were enrolled in radiology fellowship training. In 2009–2010, 72%–73% of residents remained in Canada. This dropped to 51% in 2011. In 2009–2010, 22%–23% of residents chose U.S.-based radiology training. This rose to 49% in 2011. Europe was chosen by 0%–4% of residents: all of whom were French-speaking residents, and all programs were in France. Relatively consistent percentages of radiology residents choose abdominal (19%–30%), cardiac (4%–7%), musculoskeletal (12%–20%), and pediatrics (2%–5%) from year to year. Greater variability was noted in chest (2%–9%), women's imaging (0%–14%), intervention radiology (6%–18%), and neuroradiology (2%–18%). Radiology fellowships in split subspecialties, which were available at a small number of institutions, were chosen by 8%–9% of the residents.

Conclusions

Nearly 4 of 5 residents choose radiology fellowship training. In 2011, there was a 2-fold increase in the number of residents who chose training in the United States. This may be a 1-year outlier but should be observed. A wide range of fellowships were chosen, with consistent numbers in some core fellowships and variability in others year to year. Limited exploration of the rationale for, or employability value of, radiology fellowship choices has been done in Canada. Nearly 1 of 10 residents chose split radiology fellowships, an option limited by availability at few centers. The value of expanding this option is worthy of investigation.
Magnetic Resonance Imaging Characteristics of Primary Intraspinal Peripheral Primitive Neuroectodermal Tumour
Authors: Wu Guangyao , Ghimire Prasanna , Zhu Ling , Baral Aparajita , Su Jiajia
Published: May 2012

Purpose

The purpose of our study was to describe the salient magnetic resonance imaging (MRI) findings in primary intraspinal peripheral primitive neuroectodermal tumour (PNET).

Methods

A retrospective review of the clinical and MRI images of 7 pathologically proven cases of intraspinal peripheral PNETs was performed. The various parameters, such as vertebral level of involvement; tumour location, size, focality, and margin; signal intensity of the lesion; the presence of hemorrhage or calcification; any signal voids; assessment of the adjacent cord for cord compression; cord dilatation; the presence of paraspinal tissue mass; or vertebral or other bony changes, were analysed.

Results

All 7 patients had lesions in the thoracolumbar region. Three patients had extradural lesions, 4 had intradural extramedullary lesions, and none had intramedullary lesions. Six lesions were well circumscribed. Only 1 patient had multifocal involvement. All lesions were of hypointense or isointense signal on T1-weighted imaging, whereas all but one were hyperintense on T2-weighted imaging. Lesions enhanced heterogeneously except 1 intradural extramedullary lesion, which enhanced homogeneously. A paraspinal mass was noticed in 2 patients. Vertebral collapse was present in 1 patients.

Conclusion

Intraspinal peripheral PNETs are rare spinal tumours. Although imaging characteristics are not specific, a focal circumscribed lesion in a young individual at the intramedullary, extramedullary intradural, or extradural spinal location that shows hypointense and hyperintense signal on T1- and T2-weighted images, respectively, requires PNET to be considered in the differentials.
Ubiquitination and deubiquitination of REST and its roles in cancers
Authors: Huang Zhi , Bao Shideng
Published: May 2012

REST/NRSF (the RE‐1 silencing transcription factor or neuron‐restrictive silencer factor) was originally identified as a transcriptional repressor of a number of neuronal‐specific genes in neural stem cells and non‐neuronal cells. REST functions as a master regulator in the maintenance of neural stem cells. During tumorigenesis, REST shows opposing roles in different type of cells. In human epithelial cancers such as colon cancer, REST acts as a tumor suppressor. In contrast, REST plays an oncogenic role in the development of brain tumors and other cancers. Abnormal upregulation of REST has been found in medulloblastoma, neuroblastoma and glioblastoma (GBM). Recent studies in GBMs suggest that REST exerts its oncogenic function by maintaining self‐renewal potential of glioma stem cells (GSCs).
Selectivity of the ubiquitin‐binding modules
Authors: Rahighi Simin , Dikic Ivan
Published: May 2012

Ubiquitin‐binding modules are constituents of cellular proteins that mediate the effects of ubiquitylation by making transient, non‐covalent interactions with ubiquitin molecules. While some ubiquitin‐binding modules bind single ubiquitin moieties, others are selective for specific ubiquitin chains of different linkage types and lengths. In recent years, functions of ubiquitin chains that are polymerized through their Lys or N‐terminal Met (i.e. linear chains) residues have been linked to a variety of cellular processes. Selectivity of ubiquitin‐binding modules for different ubiquitin chain types appears as a key to the distinct regulatory consequences during protein quality control pathways, receptor endocytosis, gene transcription, signaling via the NF‐κB pathway, and autophagy.
The language of SH2 domain interactions defines phosphotyrosine‐mediated signal transduction
Authors: Liu Bernard A. , Engelmann Brett W. , Nash Piers D.
Published: May 2012

Natural languages arise in an unpremeditated fashion resulting in words and syntax as individual units of information content that combine in a manner that is both complex and contextual, yet intuitive to a native reader. In an analogous manner, protein interaction domains such as the Src Homology 2 (SH2) domain recognize and “read” the information contained within their cognate peptide ligands to determine highly selective protein–protein interactions that underpin much of cellular signal transduction. Herein, we discuss how contextual sequence information, which combines the use of permissive and non‐permissive residues within a parent motif, is a defining feature of selective interactions across SH2 domains. Within a system that reads phosphotyrosine modifications this provides crucial information to distinguish preferred interactions. This review provides a structural and biochemical overview of SH2 domain binding to phosphotyrosine‐containing peptide motifs and discusses how the diverse set of SH2 domains is able to differentiate phosphotyrosine ligands.
The interplay between the disulfide bond formation pathway and cytochrome c maturation in Escherichia coli
Authors: Mavridou Despoina A.I. , Ferguson Stuart J. , Stevens Julie M.
Published: May 2012

Heme attachment to c‐type cytochromes in bacteria requires cysteine thiols in the CXXCH motif of the protein. The involvement of the periplasmic disulfide generation system in this process remains unclear. We undertake a systematic evaluation of the role of DsbA and DsbD in cytochrome c biogenesis in Escherichia coli and show unequivocally that DsbA is not essential for holocytochrome production under aerobic or anaerobic conditions. We also prove that DsbD is important but not essential for maturation of c‐type cytochromes. We discuss the findings in the context of a model in which heme attachment to, and oxidation of, the apocytochrome are competing processes.
Co‐administration phenoxodiol with doxorubicin synergistically inhibit the activity of sphingosine kinase‐1 (SphK1), a potential oncogene of osteosarcoma, to suppress osteosarcoma cell growth both in vivo and in vitro
Authors: Yao Chen , Wu Sujia , Li Dong , Ding Huimin , Wang Zuyu , Yang Yongjiang , Yan Shichang , Gu Zhangping
Published: May 2012

Elucidation of the mechanisms of chemo‐resistance and implementation of strategies to overcome it will be pivotal to improve the survival for osteosarcoma (OS) patients. We here suggest that sphingosine kinase‐1 (SphK1) might be the key factor contributing to chemo‐resistance in OS. Our Western‐blots and immunohistochemistry results showed that SphK1 is over‐expressed in multiple clinical OS tissues. Over‐expression of SphK1 in OS cell line U2OS promoted its growth and endorsed its resistance against doxorubicin, while knocking‐down of SphK1 by shRNA inhibited U2OS cell growth and increased its sensitivity to doxorubicin. Co‐administration phenoxodiol with doxorubicin synergistically inhibited SphK1 activity to trigger cellular ceramide accumulation, and achieved synergistic anti‐OS growth effect, accompanied with a significant increased of apoptosis and cytotoxicity. Increased cellular level of ceramide by the co‐administration induced the association between Akt and Protein Phosphatase 1 (PP1) to dephosphorylate Akt, and to introduce a constitutively active Akt (CA‐Akt) restored Akt activation and diminished cell growth inhibition. Further, phenoxodiol and doxorubicin synergistically activated apoptosis signal‐regulating kinase 1(ASK1)/c‐jun‐NH2‐kinase (JNK) signaling, which also contributed to cell growth inhibition. Significantly, the role of SphK1 in OS cell growth and the synergistic anti‐OS effect of phenoxodiol and doxorubicin were also seen in a mice OS xenograft model. In conclusion, our data suggest that SphK1 might be a critical oncogene of OS and co‐administration phenoxodiol with doxorubicin synergistically inhibited the activity of SphK1 to suppress osteosarcoma cell growth both in vivo and in vitro.
Adherence to dietary guidelines and 15-year risk of all-cause mortality
Authors: Russell Joanna , Flood Victoria , Rochtchina Elena , Gopinath Bamini , Allman-Farinelli Margaret , Bauman Adrian , Mitchell Paul
Published: May 2012

Past investigation of diet in relation to disease or mortality has tended to focus on individual nutrients. However, there has been a recent shift to now focus on overall patterns of food intake. The present study aims to investigate the relationship between diet quality reflecting adherence to dietary guidelines and mortality in a sample of older Australians, and to report on the relationship between core food groups and diet quality. This was a population-based cohort study of persons aged 49 years or older at baseline, living in two postcode areas west of Sydney, Australia. Baseline dietary data were collected during 1992–4, from 2897 people using a 145-item Willett-derived FFQ. A modified version of the Healthy Eating Index for Australians was developed to determine diet quality scores. The Australian National Death Index provided 15-year mortality data using multiple data linkage steps. Hazard risk (HR) ratios and 95 % CI for mortality were assessed for diet quality. Subjects in quintile 5 (highest) of the Total Diet Score had a 21 % reduced risk of all-cause mortality (HR 0·79, 95 % CI 0·63, 0·98, Ptrend= 0·04) compared with those in quintile 1 (lowest) after multivariate adjustment. The present study provides longitudinal support for a reduced risk of all-cause mortality in an older population who have greater compliance with published dietary guidelines.
Varieties of Electoral Institutions in China's Grassroots Democracy: Cross-Sectional and Longitudinal Evidence from Rural China
Authors: Lu Jie
Published: May 2012

Grassroots democracy has been practised in rural China for more than a decade. However, despite the existence of a mountain of evidence, evaluations of the quality of China's rural grassroots democracy, particularly electoral institutions, have unfortunately been inconclusive, due to primary reliance on case studies and local surveys. Moreover, the lack of comparable data over time prohibits effective studies on the evolution of grassroots democracy in Chinese villages. This article tries to provide some systematic information on how village committee elections are practised and have evolved in China, using two village surveys based on comparable national probability samples, implemented in 2002 and 2005 respectively. It further explores the validity of some key theories in contemporary literature on the uneven implementation of village committee elections in China with the help of an integrated regression model.
Marine protected areas in the UK: challenges in combining top-down and bottom-up approaches to governance
Authors: JONES PETER J. S.
Published: May 2012

This review outlines the policy frameworks for marine conservation zones (MCZs) and marine special areas of conservation (SACs), which are the main components of the emerging UK marine protected area (MPA) network. If current recommendations are implemented, the coverage of MPAs in English seas could rise to 27%. The governance challenges that this will raise are explored through case studies of MPA initiatives in south-west England. Whilst the initial processes by which MCZ recommendations have been developed provided for stakeholder participation (bottom-up), the main steer has been from central government (top-down). The subsequent designation and implementation of MCZs is likely to be more top-down. Marine SAC processes have, by contrast, been top-down from the outset. The fishing industry fears that more MPAs will lead to increasing restrictions, whilst conservationists fear that MPAs will not be sufficiently protected, potentially becoming paper MPAs. Both argue that the burden of proof should be placed on the other party. Such combinations of top-down (central government-led) and bottom-up (community and user-led) approaches and the related conflicts are typical of government-led MPAs in temperate countries that have higher governance capacities. Top-down approaches tend to dominate, but this does not mean that they cannot be combined with bottom-up approaches.
The emergence of Noun + Noun constructions with a regressive order in contemporary French?
Authors: LOOCK RUDY
Published: May 2012

This paper investigates the emergence of atypical noun+noun structures exhibiting regressive order (head-final or NN) in contemporary French such asla grève attitude(‘the strike attitude’) orla Marcelle solidarité(‘the Marcelle solidarity’). Using attested examples drawn from contemporary media, the aim of the paper is to provide a detailed description and history of these data, as well as to study its productivity through the emergence of patterns such asla N attitudeorla N Academy/Académie. Using traditional tests, the paper also investigates the morphological versus syntactic nature of the construction and concludes in favour of the former.
Alterations in Cardiac Structure and Function in a Murine Model of Chronic Alcohol Consumption
Authors: Law Brittany A. , Levick Scott P. , Carver Wayne E.
Published: May 2012

Male, wild-type, FVB strain mice were fed a nutritionally complete liquid diet supplemented with 4% ethanol v/v over a time course of 1, 2, 4, 8, 12, and 14 weeks. Controls were offered an isocaloric liquid equivalent and pair fed with their ethanol counterparts. Changes in cardiac physiology were assessed at respective time points via echocardiography. Additionally, the use of histological techniques, mRNA analysis, apoptosis determination, and immunohistochemistry were employed to determine the functional and structural changes on the heart. Echocardiograph analysis revealed a compensatory phase that occurred early in the time course (1–8 weeks) and decompensation reverting toward heart failure at weeks 12 and 14. Throughout the study, an increase in cardiomyocyte hypertrophy, cardiac fibrosis, apoptosis, TGF-β, and the presence of α-SMA-positive cells were determined. A compensatory period in mice treated with ethanol occurred early followed by a transition to a dilated phenotype over time. A number of factors may be involved in this process including the activation of myofibroblasts and their fibrotic activities that is correlated with the presence of transforming growth factor beta.
H3K4 tri-methylation in synapsin genes leads to different expression patterns in bipolar disorder and major depression
Authors: Cruceanu Cristiana , Alda Martin , Nagy Corina , Freemantle Erika , Rouleau Guy A. , Turecki Gustavo
Published: May 2012

The synapsin family of neuronal phosphoproteins is composed of three genes (SYN1, SYN2 and SYN3) with alternative splicing resulting in a number of variants with various levels of homology. These genes have been postulated to play significant roles in several neuropsychiatric disorders, including bipolar disorder, schizophrenia and epilepsy. Epigenetic regulatory mechanisms, such as histone modifications in gene regulatory regions, have also been proposed to play a role in a number of psychiatric disorders, including bipolar disorder and major depressive disorder. One of the best characterized histone modifications is histone 3 lysine 4 tri-methylation (H3K4me3), an epigenetic mark shown to be highly enriched at transcriptional start sites and associated with active transcription. In the present study we have quantified the expression of transcript variants of the three synapsin genes and investigated their relationship to H3K4me3 promoter enrichment in post-mortem brain samples. We found that histone modification marks were significantly increased in bipolar disorder and major depression and this effect was correlated with significant increases in gene expression. Our findings suggest that synapsin dysregulation in mood disorders is mediated in part by epigenetic regulatory mechanisms.
FOUNDATIONS AS TRUTHS WHICH ORGANIZE MATHEMATICS
Authors: MCLARTY COLIN
Published: May 2012

The article looks briefly at Feferman’s most sweeping claims about categorical foundations, focuses on narrower points raised in Berkeley, and asks some questions about Feferman’s own foundations. Among many different senses of foundations, the one that mathematics needs in practice is a recognized body of truths adequate to organize definitions and proofs. Finding concise principles of this kind has been a huge achievement by mathematicians and logicians. We put ZFC and categorical foundations both into this context.
Superposed epoch analyses of thermospheric response to CIRs: Solar cycle and seasonal dependencies
Authors: Liu Jing , Liu Libo , Zhao Biqiang , Lei Jiuhou , Thayer Jeffrey P. , McPherron Robert L.
Published: May 2012

Thermospheric response to Corotating Interaction Regions (CIRs) has been studied previously; however, its solar cycle and seasonal effects have not been fully investigated. Thermospheric mass density at 400 km measured by the CHAMP satellite during 2001–2008 and ∑ O/N2 from the TIMED/GUVI instrument covering a period from 2002 to 2008 are used to investigate the solar cycle and seasonal dependencies of the thermospheric response to CIRs. Our results reveal: (1) solar minimum CIRs compared to solar maximum counterparts have larger solar wind speeds before and after the stream interface. However, solar wind dynamic pressure and merging electric field are slightly larger at solar maximum than solar minimum. (2) CIR‐induced variations of ∑ O/N2 are characterized by high latitude depression and low latitude enhancement, a distinction from global enhancement of neutral density at a fixed altitude. These relative thermospheric changes are dependent on solar cycle, with a more pronounced increase in neutral density at all latitudes and a stronger decrease in ∑ O/N2 at high latitude at solar minimum than at solar maximum. (3) A seasonal asymmetry is presented in the relative deviations of thermospheric mass density and composition. On the dayside, the peak increases of neutral density at high latitudes on average are ∼40% in the summer hemisphere and ∼26% in the winter hemisphere. Nighttime neutral density changes are more remarkable than that in the same latitudinal bands of daytime and have the same seasonal preference of enhancement as the dayside. At the daytime, ∑ O/N2 at high latitudes suffers more reduction in the summer hemisphere than in the winter hemisphere. At middle latitudes, ∑ O/N2 reduces in the winter hemisphere; nevertheless, it increases slightly in the summer hemisphere.