bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thoracic venous congestion caused by thoracic disc herniation
Authors: Roger Eric P. , Chamczuk Andrea J. , Hagan Marygrace C. 
Published: February 2013

AbstractWe present what is to our knowledge the first reported case of thoracic disc herniation leading to venous congestive myelopathy (VCM), which was clinically and radiographically suggestive of Foix–Alajouanine syndrome (angiodysgenetic necrotizing myelopathy). In addition, we review current concepts in evaluating the etiology of VCM and discuss indications for surgery.
Do not throw out the baby with the bath water: choosing an effective baseline for a functional localizer of speech processing
Authors: Stoppelman Nadav , Harpaz Tamar , Ben‐Shachar Michal 
Published: February 2013

AbstractSpeech processing engages multiple cortical regions in the temporal, parietal, and frontal lobes. Isolating speech‐sensitive cortex in individual participants is of major clinical and scientific importance. This task is complicated by the fact that responses to sensory and linguistic aspects of speech are tightly packed within the posterior superior temporal cortex. In functional magnetic resonance imaging (fMRI), various baseline conditions are typically used in order to isolate speech‐specific from basic auditory responses. Using a short, continuous sampling paradigm, we show that reversed (“backward”) speech, a commonly used auditory baseline for speech processing, removes much of the speech responses in frontal and temporal language regions of adult individuals. On the other hand, signal correlated noise (SCN) serves as an effective baseline for removing primary auditory responses while maintaining strong signals in the same language regions. We show that the response to reversed speech in left inferior frontal gyrus decays significantly faster than the response to speech, thus suggesting that this response reflects bottom‐up activation of speech analysis followed up by top‐down attenuation once the signal is classified as nonspeech. The results overall favor SCN as an auditory baseline for speech processing.
Synthesis of 2,2,5,5‐Tetrasubstituted 1,4‐Dioxa‐2,5‐disilacyclohexanes via Organotin(IV)‐Catalyzed Transesterification of (Acetoxymethyl)alkoxysilanes
Authors: Erhardt Sascha A. , Hoffmann Florian , Daiß Jürgen O. , Stohrer Jürgen , Herdtweck Eberhardt , Rieger Bernhard 
Published: February 2013

Abstract(Acetoxymethyl)silanes 2, 7 a–c, and 10 a–c with at least one alkoxy group, of the general formula (AcOCH2)Si(OR)3−n(CH3)n (R: Me, Et, iPr; n=0, 1, 2), were synthesized from the corresponding (chloromethyl)silanes 1, 6 a–c, and 9 a–c by treatment with potassium acetate under phase‐transfer‐catalysis conditions. These compounds were found to provide 2,2,5,5‐organo‐substituted 1,4‐dioxa‐2,5‐disilacyclohexanes 3, 8 a–c, and 11 a–c if treated with organotin(IV) catalysts such as dioctyltin oxide. The reaction proceeds through transesterification of the acetoxy and alkoxy units followed by ring‐closure to form a dimeric six‐membered ring. The corresponding alkyl acetates are formed as the reaction by‐products. With these mild conditions, the method overcomes the drawbacks of previously reported synthetic routes to furnish 2,2,5,5‐tetramethyl‐1,4‐dioxa‐2,5‐disilacyclohexane (3) and even allows the synthesis of 1,4‐dioxa‐2,5‐disilacyclohexanes bearing hydrolytically labile alkoxy substituents at the silicon atom in good yields and high purity. These new materials were fully characterized by NMR spectroscopy, elemental analysis, mass spectrometry, and X‐ray analysis (trans‐8 a).
Development of a General Non‐Noble Metal Catalyst for the Benign Amination of Alcohols with Amines and Ammonia
Authors: Cui Xinjiang , Dai Xingchao , Deng Youquan , Shi Feng 
Published: February 2013

AbstractThe N‐alkylation of amines or ammonia with alcohols is a valuable route for the synthesis of N‐alkyl amines. However, as a potentially clean and economic choice for N‐alkyl amine synthesis, non‐noble metal catalysts with high activity and good selectivity are rarely reported. Normally, they are severely limited due to low activity and poor generality. Herein, a simple NiCuFeOx catalyst was designed and prepared for the N‐alkylation of ammonia or amines with alcohol or primary amines. N‐alkyl amines with various structures were successfully synthesized in moderate to excellent yields in the absence of organic ligands and bases. Typically, primary amines could be efficiently transformed into secondary amines and N‐heterocyclic compounds, and secondary amines could be N‐alkylated to synthesize tertiary amines. Note that primary and secondary amines could be produced through a one‐pot reaction of ammonia and alcohols. In addition to excellent catalytic performance, the catalyst itself possesses outstanding superiority, that is, it is air and moisture stable. Moreover, the magnetic property of this catalyst makes it easily separable from the reaction mixture and it could be recovered and reused for several runs without obvious deactivation.
Total Synthesis of the Hypermodified RNA Bases Wybutosine and Hydroxywybutosine and Their Quantification Together with Other Modified RNA Bases in Plant Materials
Authors: Hienzsch Antje , Deiml Christian , Reiter Veronika , Carell Thomas 
Published: February 2013

AbstractWe report an efficient synthesis of the hypermodified natural tRNA modifications wybutosine (yW) and hydroxywybutosine (OHyW). We also describe the preparation of isotopically labeled analogues for precise quantification of yW and OHyW in different tissues including plant materials. The synthesis involved the formation of the unusual tricyclic ring structure of the bases by using a catalytic, intramolecular hydroamination reaction. The basis for the synthesis is also a stereoselective coupling reaction that allows the introduction of the fully substituted side chains to the tricyclic core structure. The isotopologues of yW and OHyW, together with other isotopically labeled tRNA modifications, were ultimately used in LC‐MS quantification experiments to investigate the role of the modified bases in the translational process. Quantification was performed in the plant species Arabidopsis thaliana.
The “Click” Reaction Involving Metal Azides, Metal Alkynes, or Both: An Exploration into Multimetal Structures
Authors: Casarrubios Luis , de la Torre María C. , Sierra Miguel A. 
Published: February 2013

AbstractCuI‐catalyzed 1,3‐cycloaddition of azides and alkynes (CuAAC) is one of the most powerful synthetic methodologies known. However, its use to prepare well‐defined multimetallic structures is underdeveloped. Apart from the applications of this reaction to anchor different organometallic reagents to surfaces, polymers, and dendrimers, only isolated examples of CuAAC with metal–η1‐alkyne and metal–azide complexes to prepare multimetal entities have been reported. This concept sketches the potential of these reactions not only to prepare “a la carte” multimetal 1,2,3‐triazole derivatives, but also to discover new and unprecedented reactions.
Dynamic connection provisioning with shared protection in IP/WDM networks
Authors: Alshaer Hamada 
Published: February 2013

SUMMARYInternet protocol (IP) traffic connections arrive dynamically at wavelength‐division multiplexing (WDM) network edges with low data rates compared with the wavelength capacity, availability, and quality‐of‐service (QoS) constraints. This paper introduces a scheme to be integrated into the control and management plane of IP/WDM networks to satisfy the availability and QoS required for IP traffic connections bundled onto a single wavelength (lightpath) in WDM networks protected by shared‐backup path protection (SBPP). This scheme consists of two main operations: (i) routing multi‐granular connections and traffic grooming policies, and (ii) providing appropriate shared protection on the basis of subscribers’ service‐level agreements in terms of data rate, availability, and blocking probability. Using the Markov chain process, a probabilistic approach is developed to conceive connection blocking probability models, which can quantify the blocking probability and service utilization ofM:Nand 1:NSBPP schemes. The proposed scheme and developed mathematical models have been evaluated in terms of bandwidth blocking ratio, availability satisfaction rate, network utilization, and connection blocking probability performance metrics. The obtained research results in this paper provide network operators an operational setting parameter, which controls the allocation of working and backup resources to dynamic IP traffic connections on the basis of their priority and data rate while satisfying their requirements in terms of bandwidth and availability. Copyright © 2013 John Wiley & Sons, Ltd.
A novel cooperative transmission scheme based on superposition coding and partial relaying
Authors: Shi Sulong , Yang Longxiang , Zhu Hongbo 
Published: February 2013

SUMMARYThis paper considered the single relay system and proposed a novel repetition coding decode‐and‐forward (DF) cooperative transmission scheme on the basis of superposition coding and partial relaying. In the proposed scheme, the link disparity due to the geometry of the relay network is emphasized, and only a fraction of the information is transmitted in relay mode with the rest being transmitted directly, which benefits from the utility of superposition coding (SC) in broadcast situation. The proposed scheme is analyzed in two cases, one assumes full channel state information at the source (full CSIS), the other with only mean gain of each link known by the source (partial CSIS). For both cases, the optimal design of system parameters is considered. We investigate the achievable rate and expected rate performance for these two cases, respectively. The proposed schemed is well compared with conventional repetition coding DF, parallel coding DF, as well as another promising superposition coding relaying. It is concluded that, by designing protocols that orients to certain network geometry, better trade‐off between performance and complexity can be obtained. The analysis reveals that the gap between conventional repetition and parallel coding is largely mitigated by the proposed scheme, quite for the scenario that the relay locates relatively but not extremely closer to the source, at moderate SNR regime for both partial and full CSIS cases. The proposed scheme becomes more beneficial in severe path loss attenuation scenario. Copyright © 2013 John Wiley & Sons, Ltd.
Methylation of the glucocorticoid receptor gene promoter in bulimic women: Associations with borderline personality disorder, suicidality, and exposure to childhood abuse
Authors: Steiger Howard , Labonté Benoit , Groleau Patricia , Turecki Gustavo , Israel Mimi 
Published: February 2013

AbstractObjective:To compare levels of methylation of the glucocorticoid receptor (GR) gene (NR3C1) promoter between women with bulimia nervosa (BN) and women with no eating disorder (ED), and also to explore, in women with BN, the extent to which methylation of the GR gene promoter corresponds to childhood abuse, suicidality, or borderline personality disorder (BPD).Method:We measured methylation levels in selected NR3C1 promoter regions using DNA obtained from lymphocytes in 64 women with BN (32 selected as having a history of severe childhood abuse and 32 selected as having no such history) and 32 comparison women with no ED or history of childhood abuse.Results:Compared to noneating disordered women, women with BN and comorbid BPD (or BN with a history of suicidality) showed significantly more methylation of specific exon 1C sites. There was also a (nonsignificant) result indicative of greater methylation in some 1C sites among women with BN, when compared (as a group) to women with no ED. No parallel effects owing to childhood abuse were observed.Discussion:Our findings associate BN (when accompanied by BPD or suicidality) with hypermethylation of certain GR exon 1C promoter sites. We discuss theoretical and clinical implications of our findings. © 2013 by Wiley Periodicals, Inc. (Int J Eat Disord 2013)
A case study on spatial and temporal hydraulic variability in an alpine gravel‐bed stream based on the hydromorphological index of diversity
Authors: Gostner W. , Parasiewicz P. , Schleiss A. J. 
Published: February 2013

ABSTRACTPhysical heterogeneity is a major topic in river sciences because it is known to be a key factor for ecological integrity. In this paper, we investigated the hydraulic enviroment in an alpine gravel‐bed stream with an unaltered hydrological regime. The study was based on the hypothesis that spatial and temporal variability are correlated to the morphological template of a stream. Numerical hydrodynamic modelling was conducted at five morphologically contrasting study sites for different discharges chosen from discharge duration curves. On the basis of the resulting hydraulic variables, namely flow velocity and water depth, and of a recently proposed hydromorphological index of diversity, the differences in spatial and temporal variability were analysed by descriptive statistics. Spatial diversity was higher at morphologically natural sites than at sites that were partially or fully regulated by resectioning and bank protection. Conversely, temporal variability in the hydraulic environment was higher at regulated sites where hydraulic variables were subject to fluctuations with each small discharge modification, which is not the case for more impaired sites. Unless higher discharges with bed reshaping activity occur, natural streams are characterized not only by high spatial variability but also by a sustained persistence of aquatic habitats. Therefore, river engineering projects aimed at enhancing habitat heterogeneity should not only focus on a higher spatial variability of the physical environment but also aim for greater persistence of aquatic habitats. Copyright © 2013 John Wiley & Sons, Ltd.
Synthetic Studies for the 1,3‐Iterative Organoiron Approach to the Synthesis of Siculinine: Efficient Arylation Using a Diarylcuprate Reagent
Authors: Stephenson G. Richard , Palotai Ian M. , Thomas Sarah , Tinkl Michael 
Published: February 2013

AbstractDisubstituted (cyclohexadienyl)iron(1+) complex 2b is prepared by an improved route that starts from 1,2‐dimethoxycyclohexa‐1,4‐diene 3. In five steps, the synthesis of 2b is achieved by complexation with Fe(CO)5, hydride abstraction, hydrolysis, addition of EtO2CCH2ZrBr, and reaction with HBF4. In the presence of dimethyl sulfide, the reaction of 2b with 2‐[CH2N(CH2CH=CH2)2]‐functionalized diarylcuprate reagent 7 gave the 5α‐arylcyclohexadiene complex 1b in 88 % yield. A DFT study compared diarylzinc and diarylcuprate reagents containing chelating CH2NMe2 substituents.
Soil organic carbon enrichment of dust emissions: magnitude, mechanisms and its implications for the carbon cycle
Authors: Webb Nicholas P. , Strong Craig L. , Chappell Adrian , Marx Samuel K. , McTainsh Grant H. 
Published: February 2013

ABSTRACTSoil erosion is an important component of the global carbon cycle. However, little attention has been given to the role of aeolian processes in influencing soil organic carbon (SOC) flux and the release of greenhouse gasses, such as carbon dioxide (CO2), to the atmosphere. Understanding the magnitude and mechanisms of SOC enrichment in dust emissions is necessary to evaluate the impact of wind erosion on the carbon cycle. This research examines the SOC content and enrichment of dust emissions measured using Big Spring Number Eight (BSNE) wind‐vane samplers across five land types in the rangelands of western Queensland, Australia. Our results show that sandy soils and finer particulate quartz‐rich soils are more efficient at SOC emission and have larger SOC dust enrichment than clay‐rich aggregated soils. The SOC enrichment ratios of dusts originating from sites with sand‐rich soil ranged from 2·1–41·9, while the mean enrichment ratio for dusts originating from the clay soil was 2·1. We hypothesize that stronger inter‐particle bonds and the low grain density of the aggregated clay soil explain its reduced capacity to release SOC during saltation, relative to the particulate sandy soils. We also show that size‐selective sorting of SOC during transport may lead to further enrichment of SOC dust emissions. Two dust samples from regional transport events were found to contain 15–20% SOC. These preliminary results provide impetus for additional research into dust SOC enrichment processes to elucidate the impact of wind erosion on SOC flux and reduce uncertainty about the role of soil erosion in the global carbon cycle. Copyright © 2013 John Wiley & Sons, Ltd.
An overview of climate change impacts on European viticulture
Authors: Fraga H. , Malheiro A. C. , Moutinho‐Pereira J. , Santos J. A. 
Published: February 2013

AbstractThe importance of viticulture and of the winemaking socioeconomic sector in Europe is largely acknowledged. The most famous winemaking regions in Europe commonly present very specific environmental characteristics, where climate often plays a central role. Furthermore, given the strong influence of the atmospheric factors on this crop, climate change can significantly affect yield and wine quality under future conditions. Trends recorded in the recent past on many viticultural regions in Europe hint at an already pronounced increase in the growing‐season mean temperatures. Furthermore, climate‐change projections give evidence for significant changes in both the growing‐season temperatures and precipitations in the next decades. Although grapevines have several survival strategies, the mounting evidence for significant climate change in the upcoming decades urges adaptation and mitigation measures to be taken by the whole winemaking sector. Short‐term adaptation measures can be considered as a first protection strategy and should be focused at specific threats, mostly changes in crop‐management practices (e.g., irrigation, sunscreens for leaf protection). At long term, however, a wide range of adaptation measures should be considered (e.g., varietal and land allocation changes). An overview of the current scientific knowledge, mostly concerning the European viticulture, the potential climate change impacts, and feasible adaptation measures is provided herein.
Do Seasonal Tropical Storm Forecasts Affect Crack Spread Prices?
Authors: Fink Jason , Fink Kristin 
Published: February 2013

AbstractIndividual storms in the Gulf of Mexico have been shown to affect crack spread futures prices. As hurricanes strike refiner‐dense areas, prices of refined petroleum products rise. We find that crack spread prices are even affected by seasonal hurricane forecasts. We find this despite the difficulties of long horizon forecasting, and that refiners are only exposed in a small portion of the Atlantic basin. These effects are economically important. For example, a one standard deviation increase in the June forecast of the net tropical cyclone activity in the upcoming season increases 3‐2‐1 crack spread prices by over 9%. © 2013 Wiley Periodicals, Inc. Jrl Fut Mark 34:420–433, 2014
Birth cohort changes in the depressive symptoms of Chinese older adults: a cross‐temporal meta‐analysis
Authors: Shao Jingjin , Li Dan , Zhang Dajun , Zhang Li , Zhang Qinghua , Qi Xiaodong 
Published: February 2013

ObjectiveWith the dramatic changes in Chinese society and economy, the average depressive symptoms of Chinese older adults might have changed across their birth cohort. This study aims to examine the changes in the depressive symptoms of Chinese older adults by analyzing data from 1987 to 2010.MethodsThe study examines the changes in the Center for Epidemiologic Studies Depression Scale scores of older adults for the past 24 years (1987 to 2010) by using cross‐temporal meta‐analysis. A total of 35,299 older adults were included in the data.ResultsThe results show the following. (i) Correlations between the mean scores and data collection year are significantly positive. The mean scores in the depressive symptoms of Chinese older adults show an increase of at least 0.53 standard deviations from 1987 to 2010. (ii) The means of the scores in the depressive symptoms of both male and female older adults exhibit a significant increase in the past 24 years, with the rising tendency of women being considerably higher than that of men. (iii) Depressive symptoms show a significant increase for different age groups in the past 24 years, whereas scores for depressive symptoms have no significant difference in terms of age group.ConclusionsSocial changes play an important role in predicting the changes in the depressive symptoms of older adults. Copyright © 2013 John Wiley & Sons, Ltd.
Cyclic Voltammetric Study of Some Anti‐Chagas‐Active 1,4‐Dioxidoquinoxalin‐2‐yl Ketone Derivatives
Authors: Pérez‐Silanes Silvia , Devarapally Goutham , Torres Enrique , Moreno‐Viguri Elsa , Aldana Ignacio , Monge Antonio , Crawford Philip W. 
Published: February 2013

AbstractThe electrochemical properties of 24 1,4‐dioxidoquinoxalin‐2‐yl ketone derivatives with varying degrees of anti‐Chagas activity were investigated in the aprotic solvent dimethylformamide (DMF) by cyclic voltammetry and first‐derivative cyclic voltammetry. For this group of compounds, the first reduction in DMF was either reversible or quasireversible and consistent with reduction of the N‐oxide functionality to form the radical anion. The second reduction process for these compounds was irreversible under the conditions used. The reduction potentials correlated well with molecular structure. Substitution in the 3‐, 6‐, and 7‐ positions of the quinoxaline ring by electron‐withdrawing substituents directly affected the ease of reduction and improved the biological activities of these compounds, whereas substitution by electron‐donating groups had the opposite effect. The electrochemical results, when combined with previous work on their mechanism of action against Chagas disease and their measured anti‐Chagas activities, indicated that the quinoxaline 1,4‐dioxide system serves as a promising starting point for chemical modifications aimed at improving the T. cruzi activity via a possible bioreduction mechanism.
Copper‐Assisted/Copper‐Free Synthesis of Functionalized Dibenzo[b,f]oxepins and Their Analogs via a One‐Pot Tandem Reaction
Authors: Wang Yuqin , Chen Yanhong , He Qian , Xie Yuyuan , Yang Chunhao 
Published: February 2013

AbstractA simple, convenient, and efficient method for the formation of functionalized dibenzo[b,f]oxepins and their analogs bearing both electron‐donating and electron‐withdrawing groups has been developed via a one‐pot cascade reaction. Most starting materials are commercially available 2‐(2‐hydroxyphenyl)acetonitriles and 2‐haloarylaldehydes. The procedure makes use of Cs2CO3 as the base, and DMF as solvent under copper‐assisted/copper‐free conditions. The reaction has a comprehensive group tolerance for substrates. Most of the reactions were complete within 1 h in good‐to‐excellent yields, and the reaction temperatures were relatively low. The protocol could be scaled up to grams without lowering the yield. A reaction mechanism was also proposed.
The First Stereoselective Total Synthesis of Naturally Occurring, Bioactive (3R,5R)‐1‐(4‐Hydroxyphenyl)‐7‐phenylheptane‐3,5‐diol and the Synthesis of Its Enantiomer
Authors: Reddy Parigi Raghavendar , Sudhakar Chithaluri , Kumar Jayprakash Narayan , Das Biswanath 
Published: February 2013

AbstractThe first stereoselective total synthesis of the naturally occurring anti‐emetic diarylheptanoid (3R,5R)‐1‐(4‐hydroxyphenyl)‐7‐phenylheptane‐3,5‐diol (1) was accomplished starting from 4‐hydroxybenzaldehyde and involving a Sharpless kinetic resolution and an asymmetric epoxidation as the key steps (Scheme 2). The enantiomer 1a of this compound was also simultaneously prepared.