bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unraveling the Reaction Mechanisms Governing Methanol‐to‐Olefins Catalysis by Theory and Experiment
Authors: Hemelsoet Karen , Van der Mynsbrugge Jeroen , De Wispelaere Kristof , Waroquier Michel , Van Speybroeck Veronique 
Published: April 2013

AbstractThe conversion of methanol to olefins (MTO) over a heterogeneous nanoporous catalyst material is a highly complex process involving a cascade of elementary reactions. The elucidation of the reaction mechanisms leading to either the desired production of ethene and/or propene or undesired deactivation has challenged researchers for many decades. Clearly, catalyst choice, in particular topology and acidity, as well as the specific process conditions determine the overall MTO activity and selectivity; however, the subtle balances between these factors remain not fully understood. In this review, an overview of proposed reaction mechanisms for the MTO process is given, focusing on the archetypal MTO catalysts, H‐ZSM‐5 and H‐SAPO‐34. The presence of organic species, that is, the so‐called hydrocarbon pool, in the inorganic framework forms the starting point for the majority of the mechanistic routes. The combination of theory and experiment enables a detailed description of reaction mechanisms and corresponding reaction intermediates. The identification of such intermediates occurs by different spectroscopic techniques, for which theory and experiment also complement each other. Depending on the catalyst topology, reaction mechanisms proposed thus far involve aromatic or aliphatic intermediates. Ab initio simulations taking into account the zeolitic environment can nowadays be used to obtain reliable reaction barriers and chemical kinetics of individual reactions. As a result, computational chemistry and by extension computational spectroscopy have matured to the level at which reliable theoretical data can be obtained, supplying information that is very hard to acquire experimentally. Special emphasis is given to theoretical developments that open new perspectives and possibilities that aid to unravel a process as complex as methanol conversion over an acidic porous material.
The piecewise‐affine model of buck converter suitable for practical stability analysis
Authors: Siewniak Piotr , Grzesik Bogusław 
Published: April 2013

AbstractA generalized geometrical piecewise‐affine continuous‐time model (GMD) of buck converter under pulse‐width modulated (PWM) voltage‐mode control is presented in this paper. In general, such a model can be applied to any DC‐DC power electronic converter (PEC) in which the valves are modelled as ideal switches. The GMD is suitable and convenient to analyse PEC practical stability which is a completely different concept in relation to the notion of its stability in the classical Lyapunov sense.The PEC GMD is based on its commutation structure which is a general geometrical model of its commutation. The general idea of this model consists in determining the local dynamic behaviour of PEC trajectories on the faces of its commutation structure and/or their sections. These faces and sections are treated as geometrical objects with generalized local dynamics.The analysis of buck converter practical stability is carried out using a new method based directly on the definition of this term but not Lyapunov‐like functions as in the direct method. It has been shown that PEC Lyapunov stability does not imply its practical stability. These two concepts are complementary to each other. Copyright © 2013 John Wiley & Sons, Ltd.
The geometry of the Pareto front in biological phenotype space
Authors: Sheftel Hila , Shoval Oren , Mayo Avi , Alon Uri 
Published: April 2013

AbstractWhen organisms perform a single task, selection leads to phenotypes that maximize performance at that task. When organisms need to perform multiple tasks, a trade‐off arises because no phenotype can optimize all tasks. Recent work addressed this question, and assumed that the performance at each task decays with distance in trait space from the best phenotype at that task. Under this assumption, the best‐fitness solutions (termed the Pareto front) lie on simple low‐dimensional shapes in trait space: line segments, triangles and other polygons. The vertices of these polygons are specialists at a single task. Here, we generalize this finding, by considering performance functions of general form, not necessarily functions that decay monotonically with distance from their peak. We find that, except for performance functions with highly eccentric contours, simple shapes in phenotype space are still found, but with mildly curving edges instead of straight ones. In a wide range of systems, complex data on multiple quantitative traits, which might be expected to fill a high‐dimensional phenotype space, is predicted instead to collapse onto low‐dimensional shapes; phenotypes near the vertices of these shapes are predicted to be specialists, and can thus suggest which tasks may be at play.
N‐Acyl‐ and N‐Sulfonylformamidines from Cyanamides and Carbodiimides by Hydroalumination and Subsequent Treatment with Electrophiles
Authors: Hellmann Johannes , Rhotert Ines , Westenberg Hauke , Fröhlich Roland , Wibbeling Birgit , Uhl Werner , Würthwein Ernst‐Ulrich 
Published: April 2013

AbstractHydroalumination of cyanamides 1 with di(isobutyl)aluminium hydride affords intermediate compounds 3, which have dimeric structures in the solid state with four‐membered Al2N2 heterocycles and exocyclic N=C double bonds. The reactions of 3 with acyl chlorides yield N′,N′‐disubstituted N‐acylformamidines 5, whereas reaction with sulfonyl chlorides give the corresponding N‐sulfonylformamidines 7. In contrast, carbodiimides 8 react with dialkylaluminium hydrides R2AlH (R = tBu, iBu) to give compounds 9 in which one C=N bond of the carbodiimide is reduced to form an amidinate ligand and a second molecule of the hydride is coordinated through an Al–N and an Al–H–Al bond. Treatment of 9 with acyl chlorides yields N,N′‐disubstituted N‐acylformamidines 10, whereas reaction with sulfonyl chlorides gives the corresponding N‐sulfonylformamidines 11.
Multihop compute‐and‐forward for generalised two‐way relay channels
Authors: Wang Gengkun , Xiang Wei , Yuan Jinhong 
Published: April 2013

AbstractThe compute‐and‐forward (CaF) relaying strategy recently proposed by Nazer and Gastpar has been proven to achieve significant improvements in ‘computation rate’ than conventional relaying strategies in the multiple‐access channel. Although there have been some recent efforts on the implementations of CaF, to the best of our knowledge, there has been no published work that analyses the outage performance of CaF in the multihop two‐way relay channel (MH‐TRC). In this paper, we extend the original CaF strategy to multihop CaF (MH‐CaF) and investigate the outage performance of the proposed MH‐CaF in the generalised MH‐TRC. The transmission strategy of MH‐CaF for the L‐node K‐message MH‐TRC is generalised. The network throughput of MH‐CaF is proven to be significantly better than the non‐network coding (Non‐NC) scheme for the MH‐TRC with a large number of messages. The outage probabilities for both Non‐NC and MH‐CaF schemes are derived for comparison. Numerical results show that for a five‐node MH‐TRC, MH‐CaF can achieve a better outage performance than Non‐NC when the number of messages is less than 12. Furthermore, it is also demonstrated that MH‐CaF is always superior to Non‐NC in outage performance when the number of nodes of the MH‐TRC is relatively large. Copyright © 2013 John Wiley & Sons, Ltd.
Auditor's Guide to M&A Scandals
Authors: Shapiro David 
Published: April 2013

AbstractCompanies have grown ever larger by regularly consolidating and acquiring other businesses, in an effort to compete globally. The author of this article, a veteran financial investigator, has worked for the FBI, a New Jersey county prosecutor's office, and others. He says that the countervailing force of antitrust enforcement too often plays second fiddle or is passive in the face of freewheeling, deregulated merger and acquisition (M&A) activity. In this article, he reveals some of the detrimental by‐products of M&A, including the increased risk of corruption. He also discusses the auditor's role in detecting—and preventing—these adverse M&A by‐products and risks. © 2013 Wiley Periodicals, Inc.
The HPQ/AU Scandal: What Went Wrong?
Authors: Shapiro David 
Published: April 2013

AbstractIn 2011, Hewlett‐Packard (HPQ) acquired Autonomy PLC (AU), the United Kingdom's largest software provider. But after a whistleblower complained of deficient accounting and financial reporting at AU, HPQ announced a write‐down of the valuation recorded from the AU acquisition in the amount of $8.8 billion—including a whopping $5 billion from alleged accounting improprieties! Why didn't auditors and others uncover this before the deal went through? What went wrong? © 2013 Wiley Periodicals, Inc.
Nitrogen removal from temperate anaerobic–aerobic two‐stage biological systems: impact of reactor type and wastewater strength
Authors: Eusebi Anna L. , Martin‐Garcia Nacho , McAdam Ewan J. , Jefferson Bruce , Lester John N. , Cartmell Elise 
Published: April 2013

AbstractBACKGROUNDThere is a need to examine the impact of anaerobic reactor type and wastewater strength on anaerobic–aerobic two‐stage biological systems for temperate wastewater treatment An expanded granular sludge blanket reactor and an anaerobic membrane bioreactor for crude wastewater treatment with downstream aerobic biological treatment were studied together with increasing the organic concentration by fortifying the crude wastewater with primary sludge.RESULTSA chemical oxygen demand and ammonia compliant effluent was produced from the anaerobic–aerobic two‐stage process. Due to the enhanced organics removal achieved by the membrane, a lower denitrification rate, kd, was recorded for the anaerobic membrane bioreactor effluent treatment. However, the residual organic carbon in the anaerobic effluents from both the expanded granular sludge blanket reactor and the anaerobic membrane bioreactor treating crude wastewater was not of sufficient quality to support denitrification. Complete nitrification was achieved during downstream treatment of the fortified effluent. In addition, fortification increased kd to values analogous to exogenous carbon substrates.CONCLUSIONSIt is postulated that fortification currently presents the most sustainable strategy for anaerobic–aerobic two‐stage biological systems due to a combination of enhanced methane production and denitrification. © 2013 Society of Chemical Industry
Nitrate reduction coupled with pyrite oxidation in the surface sediments of a sulfide‐rich ecosystem
Authors: Hayakawa Atsushi , Hatakeyama Mizuho , Asano Ryoki , Ishikawa Yuichi , Hidaka Shin 
Published: April 2013

AbstractMost studies of denitrification have focused on organic carbon as an electron donor, but reduced sulfur can also support denitrification. Few studies have reported nitrate (NO3−) reduction coupled with pyrite oxidation and its stoichiometry in surface sediments, especially without experimental pyrite addition. In this study, we evaluated NO3− reduction coupled with sulfur oxidation by long‐term incubation of surface sediments from a sulfide‐rich ecosystem in Akita Prefecture, Japan. The surface sediments were sampled from a mud pool and a riverbed. Fresh sediments and water were incubated under anoxic conditions (and one oxic condition) at 20°C. NO3− addition increased the SO42− concentration and decreased the NO3− concentration. SO42− production (∆SO42−) was strongly and linearly correlated with NO3− consumption (∆NO3−) during the incubation period (R2 = 0.983, P < 0.01, and n = 8), and the slope of the regression (∆NO3−/∆SO42−) and the stoichiometry indicated sulfur‐driven NO3− reduction by indigenous autotrophic denitrifying bacteria. Framboidal pyrite and marcasite (both FeS2) were present in the sediments and functioned as the electron donors for autotrophic denitrification. Both ∆NO3− and ∆SO42− were higher in the riverbed sediment than in the mud pool sediment, likely because of the higher amount of easily oxidizable S (pyrite) in the riverbed sediment. Consistently low ammonium (NH4+) concentrations indicated that NO3− reduction by dissimilatory NO3− reduction to NH4+ was small but could not be disregarded. Our results demonstrate that sulfide‐rich ecosystems with easily oxidizable metal‐bound sulfides such as FeS2 near the ground surface may act as denitrification hot spots.
Serological characterization of dengue virus infections observed among dengue hemorrhagic fever/dengue shock syndrome cases in upper Myanmar
Authors: Ngwe Tun Mya Myat , Thant Kyaw Zin , Inoue Shingo , Kurosawa Yae , Lwin Yee Yee , Lin Sanda , Aye Kay Thi , Thet Khin Pe , Myint Tin , Htwe Khin , Mapua Cynthia A. , Natividad Filipinas F. , Hirayama Kenji , Morita Kouichi 
Published: April 2013

AbstractIn Myanmar, dengue fever (DF)/dengue hemorrhagic fever (DHF) is one of the leading causes of morbidity and mortality among children. From Pyinmana Hospital in 2004 and Mandalay Children Hospital in 2006, 160 patients diagnosed clinically to have DHF/dengue shock syndrome (DSS) were examined for immunoglobulin M (IgM) and IgG levels. A focus reduction neutralization test was also used to determine primary or secondary dengue virus (DENV) infection. By using IgM‐capture ELISA, 139 cases were confirmed as DENV infections. Of these IgM‐positives, 94 samples were collected 7–24 days from the onset of illness, to which 13 (14%) and 81 (86%) were determined to be primary and secondary DENV infections, respectively. The 13 primary DENV infection cases were spread among the various severity groups (DHF grade I–IV and DSS) and represented age groups ranging from <1 year of age to 9 years of age. The patients in these primary infection cases showed a remarkably high IgM with a low IgG titer response compared with the secondary infection cases. No significant differences were observed in IgG titers with clinical severity. The data obtained in this study suggest that primary DENV infection cases exist certainly among DHF/DSS cases in Myanmar, and that additional mechanism(s) aside from the antibody‐dependent enhancement mechanism could have influenced the clinical severity in DHF/DSS cases.J. Med. Virol. 85:1258–1266, 2013.© 2013 Wiley Periodicals, Inc.
The Effect of the Hydrophilic/Hydrophobic Ratio of Polymeric Micelles on their Endocytosis Pathways into Cells
Authors: Zhang Zhao , Qu Qianqian , Li Jinrong , Zhou Shaobing 
Published: April 2013

AbstractFluorescein isothiocyanate (FITC), a fluorescent probe, is coupled to amphiphilic monomethoxy poly(ethylene glycol)‐block‐poly(ε‐caprolactone) (mPEG‐PCL) copolymers. FITC‐labeled mPEG‐PCL copolymers self‐assemble into micelles through the solvent evaporation method. The cellular internalization is examined using fluorescence microscopy on incubation of NIH‐3T3 fibroblasts with micelles or free FITC solution. The effect of the hydrophilic/hydrophobic ratio on the endocytosis mechanisms is evaluated by fluorescence microscopy on culturing of human hepatoblastoma cells and human umbilical vein endothelial cells, individually, mixed with the micelles holding the same parameters including micelle size, shape, and surface charges. magnified image
Anisotropic Shape‐Memory Elastomeric Composites: Fabrication and Testing
Authors: Rodriguez Erika D. , Weed Derek C. , Mather Patrick T. 
Published: April 2013

AbstractAnisotropic shape‐memory elastomeric composites (A‐SMEC) are fabricated by infiltrating an aligned electrospun fibrous web with an elastomer, and curing. Mechanical testing proves strong anisotropy in Young's modulus (EY), strain‐to‐failure (ϵf), and yield stress (σy) observed with averages of EY = 48.4 and 4.0 MPa, ϵf = 198 and 351%, and σy = 4.6 and 0.9 MPa for longitudinal and transverse loading directions, with respect to the fibrous web's orientation. Shape‐memory (SM) characterization reveals modest anisotropy in the shape fixing ratios (Rf), yet seemingly isotropic shape recovery (Rr) nearing completeness. Such soft, anisotropic materials may be used in laminated composite elastomers.magnified image
Abelian varieties over finitely generated fields and the conjecture of Geyer and Jarden on torsion
Authors: Arias‐de‐Reyna Sara , Gajda Wojciech , Petersen Sebastian 
Published: April 2013

AbstractIn this paper we prove the Geyer‐Jarden conjecture on the torsion part of the Mordell‐Weil group for a large class of abelian varieties defined over finitely generated fields of arbitrary characteristic. The class consists of all abelian varieties with big monodromy, i.e., such that the image of Galois representation on ℓ‐torsion points, for almost all primes ℓ, contains the full symplectic group.
Age‐ and gender‐specific nomograms for single and dual post‐void residual urine in healthy children
Authors: Chang Shang‐Jen , Chiang I‐Ni , Hsieh Cheng‐Hsing , Lin Chia‐Da , Yang Stephen Shei‐Dei 
Published: April 2013

AbstractPurposeTo establish the first age‐ and gender‐specific nomograms for single and two consecutive tests for post‐void residual urine (PVR).Material and MethodsHealthy children aged 4–12 years were enrolled for two sets of uroflowmetry and PVR. The first PVR and the lower value of the two consecutive PVRs of each child with a voided volume ≥50 ml were included for construction of Single‐ and Dual‐PVR nomograms. Children with possible urinary tract infection or lower urinary tract dysfunctions were excluded.Results and LimitationsTotally, 1,128 children (583 boys and 545 girls) with a mean age of 7.7 ± 2.2 years were eligible for analysis. The 95th percentile of Single‐PVR for all children was 27.2 ml, or 19.2% of bladder capacity (BC), while that for Dual‐PVR were 11.2 ml or 6.0% of BC, respectively. Multivariate studies showed that PVR was positively associated with BC, negatively associated with age, higher in boys than girls, and higher in abnormal uroflow patterns. For children aged ≤6 years, a single PVR >30 ml or >21% BC, or repetitive PVR >20 ml or >10% BC can be regarded as elevated. For children aged ≥7 years, a single PVR >20 ml or 15% BC, or repetitive PVR >10 ml or 6% BC can be redefined as elevated.ConclusionsAge, gender, and BC should be taken into considerations at interpretation of PVR tests in children. Repeating PVR test is recommended when a single PVR is higher than the 95th percentile of age‐ and gender‐specific PVR. Neurourol. Urodynam. 32: 1014–1018, 2013. © 2013 Wiley Periodicals, Inc.
Childhood intelligence and adult obesity
Authors: Kanazawa Satoshi 
Published: April 2013

AbstractObjective: Recent studies conclude childhood intelligence has no direct effect on adult obesity net of education, but evolutionary psychological theories suggest otherwise.Design and Methods: A population (n = 17,419) of British babies has been followed since birth in 1958 in a prospectively longitudinal study. Childhood general intelligence is measured at 7, 11, and 16, and adult BMI and obesity are measured at 51.Results: Childhood general intelligence has a direct effect on adult BMI, obesity, and weight gain, net of education, earnings, mother's BMI, father's BMI, childhood social class, and sex. More intelligent children grow up to eat more healthy foods and exercise more frequently as adults.Conclusion: Childhood intelligence has a direct effect on adult obesity unmediated by education or earnings. General intelligence decreases BMI only in adulthood when individuals have complete control over what they eat.
Paradoxical protective effect of central obesity in patients with suspected stable coronary artery disease
Authors: Bechlioulis Aris , Vakalis Konstantinos , Naka Katerina K. , Bourantas Christos V. , Papamichael Nikolaos D. , Kotsia Anna , Tzimas Thomas , Pappas Konstantinos , Katsouras Christos S. , Michalis Lampros K. 
Published: April 2013

AbstractObjective:Increased body mass index (BMI) has been paradoxically inversely associated with the presence of angiographic coronary artery disease (CAD). Central obesity measures, considered to be more appropriate for assessing obesity‐related cardiovascular risk, have been little studied in relation to the presence of CAD. The aim was to investigate the association of central obesity with the presence of angiographic CAD as well as the prognostic significance of obesity measures in CAD prediction when added to other cardiovascular risk factors.Design and Methods:Patients with suspected stable CAD (n = 403, age 61 ± 10 years, 302 males) referred for diagnostic coronary angiography with documented anthropometric data were enrolled.Results:Significant angiographic CAD was found in 51% of patients. Both BMI (OR = 0.64 per 1 SD increase, P = 0.001) and waist circumference (WC) (OR = 0.54 per 1 SD increase, P < 0.001) were inversely associated with the presence of CAD even after adjustment for cardiovascular risk factors. In subgroup analysis, BMI and WC were significantly inversely associated with the presence of CAD in males, non diabetics, patients >60 years old and patients with Framingham risk score (FRS) >20% (P < 0.01 for all). The addition of BMI or WC in FRS‐based regression models improved prediction of CAD (P = 0.03 and P < 0.001 for BMI and WC respectively) without a significant difference between the two models (P = 0.08).Conclusions:Central and overall obesity were independently associated with a reduced prevalence of angiographic CAD, lending further credence to the existence of the ‘obesity paradox’. Obesity measures may further improve risk discrimination for the presence of CAD when added in an established risk score such as FRS.
New developments in the law for obesity discrimination protection
Authors: Pomeranz Jennifer L. , Puhl Rebecca M. 
Published: April 2013

AbstractBackground:Obese individuals are frequent targets of weight‐based discrimination, particularly in the employment setting. Victims of weight discrimination have sought legal restitution like others who have suffered from different forms of discrimination. However, in the vast majority of the United States, body weight is not a protected class and weight‐based employment discrimination does not provide a basis for a legal claim. Some have attempted to seek legal recourse under the Rehabilitation Act of 1973 or the Americans with Disabilities Act of 1990 (collectively, the ADA), which protect against discrimination based on mental or physical disabilities in a variety of settings. Until recently, claims of weight discrimination under the ADA have also been largely unsuccessful. However, Congress recently passed the ADA Amendments Act, expanding the definition of what constitutes a disability and incorporating a broad view of ADA's coverage.Objective:This short communication provides an update of the law as it relates to employment based discrimination of obese people. The authors propose a legislative direction for future legal recourse.Design and Methods:The authors conducted legal research into the ADA Amendments Act, and synthesized this work relating to discrimination against weight in the employment context.Results:In light of the ADA Amendments Act, courts and the Equal Employment Opportunity Commission have provided protection for severely obese people from discrimination based on actual or perceived disability in the employment context.Conclusion:The authors discuss this positive legal development and additionally propose a targeted solution to address weight discrimination in the employment setting. National polling suggests there is considerable public support for such a measure. The authors thus recommend the implementation of a “Weight Discrimination in Employment Act” modeled after the Age Discrimination in Employment Act to adequately address this pervasive and damaging injustice toward individuals who are affected by obesity.