bluuebunny/crossref_metadata_2025 huggingface dataset:
Habilidades directivas desde la percepción de los subordinados: Un enfoque relacional para el estudio del liderazgo
Authors: Cetina Thelma , Ortega Isaac , Aguilar Cecilia
Published: March 2013

Algunos autores han señalado la necesidad de buscar nuevos paradigmas para estudiar el liderazgo, una de ellas es reconocer el carácter social de este proceso, propuesta en la cual se enmarca este trabajo que se propuso considerar la percepción que tienen los miembros del grupo sobre las habilidades directivas de sus jefes como elemento que influye en la construcción de la legitimidad del poder conferido por el puesto o cargo que se ocupa. Se aplicó la Escala de Habilidades Directivas a 171 trabajadores que formaban parte de uno de los siete grupos de trabajo que integraron la muestra. Los participantes evaluaron a su respectivo jefe y con los datos obtenidos se realizó un análisis de regresión ordinal a través del cual se determinó que las habilidades de relaciones humanas y de visión compartida son buenos predictores de la percepción que tienen los subordinados sobre qué tan adecuado es su jefe para el puesto, la calidad de su desempeño como jefe y el respeto que se han ganado, siendo estos algunos de los indicadores de legitimidad propuestos en la literatura.
Liderazgo Directivo: Claves para una Mejor Escuela
Authors: Anderson Stephen
Published: March 2013

El propósito de este trabajo es presentar los avances en el conocimiento acumulado respecto del liderazgo educativo a nivel de establecimientos educacionales. Se señala y describe la relevancia del liderazgo directivo en el desarrollo de cambios y mejoras edu- cativas; las sendas de influencia; y las categorías de prácticas del liderazgo efectivo. Este trabajo propone cuatro desafíos para la implementación de prácticas: la concreción de acciones en contextos específicos, la descripción de la naturaleza del cambio, el necesario apoyo a los líderes, y la distribución de prácticas. Se concluye la necesidad de desarrollar una mayor comprensión sobre cómo se pueden adaptar los principios generales de las prácticas claves a diferentes contextos, así como saber más sobre las mejores estrategias para apoyar la difusión de buenas prácticas a una escala mayor.
Yoga en el Tratamiento de Adicciones. La experiencia de dos años de práctica de yoga con pacientes del Centro de Rehabilitación Takiwasi.
Authors: Brito Pons Gonzalo
Published: March 2013

Este artículo presenta en detalle y desde una mirada experiencial la utilización de la práctica del yoga como técnica terapéutica complementaria en el tratamiento de adic- ciones. Tomando en cuenta que, pese a la popularidad actual de esta práctica, existen pocas descripciones detalladas de su utilización en contextos clínicos, se ofrece en este artículo una descripción general de la filosofía y práctica del yoga, sus beneficios a nivel físico y psicológico, su implementación en un contexto clínico particular -el tratamiento de adicciones- y finalmente la propia perspectiva de los pacientes en tratamiento sobre el rol del yoga en su proceso de rehabilitación.
Sensitivity of tropospheric chemical composition to halogen-radical chemistry using a fully coupled size-resolved multiphase chemistry/global climate system – Part 1: Halogen distributions, aerosol composition, and sensitivity of climate-relevant gases
Authors: Long M. S. , Keene W.C. , Easter R. C. , Sander R. , Liu X. , Kerkweg A. , Erickson D.
Published: March 2013

Abstract. Observations and model studies suggest a significant but highly non-linear role for halogens, primarily Cl and Br, in multiphase atmospheric processes relevant to tropospheric chemistry and composition, aerosol evolution, radiative transfer, weather, and climate. The sensitivity of global atmospheric chemistry to the production of marine aerosol and the associated activation and cycling of inorganic Cl and Br was tested using a size-resolved multiphase coupled chemistry/global climate model (National Center for Atmospheric Research's Community Atmosphere Model (CAM); v3.6.33). Simulation results showed strong meridional and vertical gradients in Cl and Br species. The simulation reproduced most available observations with reasonable confidence permitting the formulation of potential mechanisms for several previously unexplained halogen phenomena including the enrichment of Br− in submicron aerosol, and the presence of a BrO maximum in the polar free troposphere. However, simulated total volatile Br mixing ratios were generally high in the troposphere. Br in the stratosphere was lower than observed due to the lack of long-lived organobromine species in the simulation. Comparing simulations using chemical mechanisms with and without reactive Cl and Br species demonstrated a significant temporal and spatial sensitivity of primary atmospheric oxidants (O3, HOx, NOx), CH4, and non-methane hydrocarbons (NMHC's) to halogen cycling. Simulated O3 and NOx were globally lower (65% and 35%, respectively, less in the planetary boundary layer based on median values) in simulations that included halogens. Globally, little impact was seen in SO2 and non-sea-salt SO42− processing due to halogens. Significant regional differences were evident: the lifetime of nss-SO42− was extended downwind of large sources of SO2. The burden and lifetime of DMS (and its oxidation products) were lower by a factor of 5 in simulations that included halogens, versus those without, leading to a 20% reduction in nss-SO42− in the Southern Hemisphere planetary boundary layer based on median values.
Ion temperature anisotropy effects on threshold conditions of a shear-modified current driven electrostatic ion-acoustic instability in the topside auroral ionosphere
Authors: Perron P. J. G. , Noël J.-M. A. , Kabin K. , St-Maurice J.-P.
Published: March 2013

Abstract. Temperature anisotropies may be encountered in space plasmas when there is a preferred direction, for instance, a strong magnetic or electric field. In this paper, we study how ion temperature anisotropy can affect the threshold conditions of a shear-modified current driven electrostatic ion-acoustic (CDEIA) instability. In particular, this communication focuses on instabilities in the context of topside auroral F-region situations and in the limit where finite Larmor radius corrections are small. We derived a new fluid-like expression for the critical drift which depends explicitly on ion anisotropy. More importantly, for ion to electron temperature ratios typical of F-region, solutions of the kinetic dispersion relation show that ion temperature anisotropy may significantly lower the drift threshold required for instability. In some cases, a perpendicular to parallel ion temperature ratio of 2 and may reduce the relative drift required for the onset of instability by a factor of approximately 30, assuming the ion-acoustic speed of the medium remains constant. Therefore, the ion temperature anisotropy should be considered in future studies of ion-acoustic waves and instabilities in the high-latitude ionospheric F-region.
Towards community-driven paleogeographic reconstructions: integrating open-access paleogeographic and paleobiology data with plate tectonics
Authors: Wright N. , Zahirovic S. , Müller R. D. , Seton M.
Published: March 2013

Abstract. A variety of paleogeographic reconstructions have been published, with applications ranging from paleoclimate, ocean circulation and faunal radiation models to resource exploration; yet their uncertainties remain difficult to assess as they are generally presented as low-resolution static maps. We present a methodology for ground-truthing the digital Palaeogeographic Atlas of Australia by linking the GPlates plate reconstruction tool to the global Paleobiology Database and a Phanerozoic plate motion model. We develop a spatio-temporal data mining workflow to validate the Phanerozoic Palaeogeographic Atlas of Australia with paleoenvironments derived from fossil data. While there is general agreement between fossil data and the paleogeographic model, the methodology highlights key inconsistencies. The Early Devonian paleogeographic model of southeastern Australia insufficiently describes the Emsian inundation that may be refined using biofacies distributions. Additionally, the paleogeographic model and fossil data can be used to strengthen numerical models, such as the dynamic topography and the associated inundation of eastern Australia during the Cretaceous. Although paleobiology data provide constraints only for paleoenvironments with high preservation potential of organisms, our approach enables the use of additional proxy data to generate improved paleogeographic reconstructions.
Evaluation of dust and trace metal estimates from the Community Multiscale Air Quality (CMAQ) model version 5.0
Authors: Appel K. W. , Pouliot G. A. , Simon H. , Sarwar G. , Pye H. O. T. , Napelenok S. L. , Akhtar F. , Roselle S. J.
Published: March 2013

Abstract. The Community Multiscale Air Quality (CMAQ) model is a state-of-the-science air quality model that simulates the emission, transformation, transport and fate of the many different air pollutant species that comprise particulate matter (PM), including dust (or soil). The CMAQ model version 5.0 (CMAQv5.0) has several enhancements over the previous version of the model for estimating the emission and transport of dust, including the ability to track the specific elemental constituents of dust and have the model-derived concentrations of those elements participate in chemistry. The latest version of the model also includes a parameterization to estimate emissions of dust due to wind action. The CMAQv5.0 modeling system was used to simulate the entire year 2006 for the continental United States, and the model estimates were evaluated against daily surface based measurements from several air quality networks. The CMAQ modeling system generally did well replicating the observed soil concentrations in the western United States; however the model consistently overestimated the observed soil concentrations in the eastern United States, regardless of season. The performance of the individual trace metals was generally good at the rural network sites, with relatively small biases for Fe, Al, Si and Ti throughout the year, while Ca, K and Mn were overestimated and Mg underestimated. For the urban sites, Fe, Mg and Mn, while overestimated, had comparatively better performance throughout the year than the other trace metals, which were consistently overestimated, including very large overestimations of Al, Ti and Si in the fall. An underestimation of nighttime mixing in the urban areas appears to contribute to the overestimation of trace metals. Removing the anthropogenic fugitive dust (AFD) emissions and the effects of wind-blown dust (WBD) lowered the model soil concentrations. However, even with both AFD emissions and WBD effects removed, soil concentrations were still often overestimated, suggesting that there are other sources of errors in the modeling system that contribute to the overestimation of soil components. Efforts are underway to improve both the nighttime mixing in urban areas and the spatial and temporal distribution of dust related emissions sources in the emissions inventory.
Stable water isotope variation in a Central Andean watershed dominated by glacier and snowmelt
Authors: Ohlanders N. , Rodriguez M. , McPhee J.
Published: March 2013

Abstract. Central Chile is an economically important region for which water supply is dependent on snow- and ice melt. Nevertheless, the relative contribution of water supplied by each of those two sources remains largely unknown. This study represents the first attempt to estimate the region's water balance using stable isotopes of water in streamflow and its sources. Isotopic ratios of both H and O were monitored during one year in a high-altitude basin with a moderate glacier cover (11.5%). We found that the steep altitude gradient of the studied catchment caused a corresponding gradient in snowpack isotopic composition and that this spatial variation had a profound effect on the temporal evolution of streamflow isotopic composition during snowmelt. Glacier melt and snowmelt contributions to streamflow in the studied basin were determined using a quantitative analysis of the isotopic composition of streamflow and its sources, resulting in a glacier melt contribution of 50–90% for the unusually dry melt year of 2011/2012. This suggests that in (La Niña) years with little precipitation, glacier melt is an important water source for central Chile. Predicted decreases in glacier melt due to global warming may therefore have a negative long-term impact on water availability in the Central Andes. The pronounced seasonal pattern in streamflow isotope composition and its close relation to the variability in snow cover and discharge presents a potentially powerful tool to relate discharge variability in mountainous, melt-dominated catchments with related factors such as contributions of sources to streamflow and snowmelt transit times.
Catchment features controlling nitrogen dynamics in running waters above the tree line (central Italian Alps)
Authors: Balestrini R. , Arese C. , Freppaz M. , Buffagni A.
Published: March 2013

Abstract. The study of nitrogen cycling in mountain areas has a long tradition, as it was applied to better understand and describe ecosystem functioning, as well as to quantify long-distance effects of human activities on remote environments. Nonetheless, very few studies, especially in Europe, have considered catchment features controlling nitrogen dynamics above the tree line with focus on running waters. In this study, relationships between some water chemistry descriptors – including nitrogen species and dissolved organic carbon (DOC) – and catchment characteristics were evaluated for a range of sites located above the tree line (1950–2650 m a.s.l.) at Val Masino, in the central Italian Alps. Land cover categories as well as elevation and slope were assessed at each site. Water samples were collected during the 2007 and 2008 snow free periods, with a nearly monthly frequency. In contrast to dissolved organic nitrogen, nitrate concentrations in running waters showed a spatial pattern strictly connected to the fractional extension of tundra and talus in each basin. Exponential models significantly described the relationships between maximum NO3 and the fraction of vegetated soil cover (negative relation) and talus (positive relation), explaining almost 90% of nitrate variation in running waters. Similarly to nitrate but with an opposite behavior, DOC was positively correlated with vegetated soil cover and negatively correlated with talus. Therefore, land cover can be considered one of the most important factors affecting water quality in high-elevation catchments with contrasting effects on N and C pools.
Identity in the Medieval Mediterranean World of Merchants and Pirates
Authors: Reyerson Kathryn
Published: March 2013

Identity in the medieval Mediterranean world was complex and multifaceted. Medieval Europeans, especially merchants, borrowed and shifted identities according to the circumstances. They might sail under the flags of other polities and become pirates and privateers on occasion. This study examines cases of shifting identities, multiple identities, borrowing of identities, and mistaken identities within a shared Mediterranean maritime culture, using literary evidence, judicial records, treaties, and documents of practice.
Islamic Resurgence and Its Consequences in the Egyptian Experience
Authors: Guirguis Max
Published: March 2013

Although Islamic fundamentalism has received increasing attention following the September 11 attacks, it had been in the making for well over half a century, especially in Egypt. The Islamist movement began in Egypt in the early part of the twentieth century, during the British occupation. But no sooner had the movement found its footing under the leadership of the Muslim Brotherhood than it was suppressed by Nasser's despotic regime and his nationalist ideology. The Islamists made a comeback under Sadat's permissive policies and continued to make gains under Mubarak, whose recent ouster left a power vacuum that the Islamists eagerly filled.
Becoming “In the Know” About Parent-Child Collaborations in Mathematics
Authors: Mistretta Regina
Published: March 2013

In this article, I describe the investigative efforts of a group of preservice teachers to acquire an understanding of how and why parents and children work together in mathematics the way they do. First, I share literature that supports the need for inquiry into parent-child collaborations in mathematics. I then detail the study: the participants, learning environment, modes of inquiry, findings, and their implications for teacher practice. Findings concern the understandings the preservice teachers acquired about parent-child collaborations and their enhanced practices for supporting classroom families. This work is intended to contribute to the body of knowledge on preparing teachers to inquire about and cultivate parent-child collaborations in mathematics.
Preservice-Teacher Interviews: A Tool for Motivating Mathematics Learning
Authors: Thanheiser Eva , Philipp Randolph A. , Fasteen Jodi , Strand Krista , Mills Briana
Published: March 2013

Helping prospective elementary school teachers (PSTs) recognize that they have something useful to learn from university mathematics courses remains a constant challenge. We found that an initial content interview with PSTs often led to the PSTs' changing their beliefs about mathematics and about their understanding of mathematics, leading to the recognition that (a) there is something to learn beyond procedures, (b) their own knowledge is limited and they need to know more to be able to teach, and (c) engaging in the mathematical activities in their content courses will lead them to learning important content. Thus, such an interview can set PSTs on a trajectory characterized by greater motivation to learn in their content courses.
Contextualizing the Current Crisis: Post-fordism, Neoliberal Restructuring, and Financialization
Authors: Tauss Aaron
Published: March 2013

The article argues that the current financial crisis that began unfolding in late 2007 cannot be explained merely by institutional failure, false economic theories, or human misbehavior. Instead, the crisis must be analyzed against the backdrop of the internal contradictions of capitalist accumulation and the gradual disintegration of the post-war hegemonic world order under U.S. leadership. The specifics of the crisis are inherently related to the failure of Fordism in the 1970s and the emergence of a post-Fordist, neoliberal, and finance-driven regime of accumulation that was pushed to its limits in the lead-up to the current downturn.
Seguridad internacional y multilateralismo: las organizaciones internacionales y la intervención en Libia
Authors: Querejazu Escobari Amaya
Published: March 2013

Since the end of World War II multilateralism has been the way through which states have faced threats against peace and international security, enforcing actions according to the Security Council (SC) prescriptions and the United Nations (UN) Charter. Nevertheless the performance of international organizations (IO) in the response to those threats has been criticized. Beyond ethical considerations on whether or not humanitarian interventions should be undertaken, the paper aims to examine if multilateralism is facing a crisis, specifically addressing its efficiency, legitimacy and equality, especially in the decision making process as well as in the enforcement of institutional decisions. The role of IO in the intervention in Libya is offered as a case study.
Dinámica del comercio ilícito de personas: el caso de Colombia-Oriente Asiático
Authors: Hurtado Mónica , Pereira-Villa Catherine
Published: March 2013

This study characterizes the dynamics of transnational trafficking in humans for commercial sexual exploitation from a business dimension. Based on a review of Colombian judicial records (2005-2011), this study analyses the interaction between victims, traffickers and intermediaries involved in cases of trafficking between Colombia and East Asia. This research argues that victims occasionally have a double-condition for a trafficking network: on the one hand, they are subjects to the extent that they make decisions; and on the other, they are objects as they cannot exercise their free will. Since victims make decisions based on asymmetric information, this facilitates their exploitation and explains in part why trafficking in persons is both a profitable and growing illegal business. Among other topics, this study estimates the profits obtained by a network by exploiting a Colombian victim in Hong Kong or Singapore, and suggests criteria to evaluate exploitation.
Clear Cornea with Large Central Descemets Membrane Tears following Birth Trauma
Authors: Agarwal Shweta , Radhika N , Padmanabhan Prema
Published: March 2013

To report a case of clear cornea with absent descemets membrane following birth trauma. Clinical history was taken and a detailed ophthalmic examination including slitlamp biomicroscopy, anterior segment ocular coherence tomography (ASOCT), pentacam, corneal topography, specular microscopy and pachymetry done. A large 6 mm diameter central area of clear cornea devoid of descemets membrane was seen in the affected eye. A case of clear cornea despite a large area of absent descemets membrane with a reasonably well functioning endothelium following birth trauma.
Central Retinal Artery Occlusion and Simultaneous Third Nerve Palsy in HIV Patient
Authors: Kothari Raghnandan , Dhaytadak Priyanka , Gogri Pratik
Published: March 2013

Ocular manifestations can occur in approximately 70% of human immunodeficiency virus acquired immune deficiency syndrome patients and posterior segment involvement seen in about 50% cases is the most common presentation. We report a case of 39 years old HIV positive male who presented with unilateral central retinal artery occlusion with simultaneous third nerve palsy. Magnetic resonance Imaging brain revealed acute infarct in thalamo-capsular region on right side and old lacunar infarct involving pons on left side. We report this case for its rare presentation of CRAO and simultaneous third nerve palsy in HIV infection.
Do Chimpanzee Nests Serve an Anti‐Predatory Function?
Authors: STEWART FIONA A. , PRUETZ J. D.
Published: March 2013

Sleep is a vulnerable state for animals as it compromises the ability to detect predators. The evolution of shelter construction in the great apes may have been a solution to the trade‐off between restorative sleep and predation‐risk, which allowed a large bodied ape to sleep recumbent in a safe, comfortable spot. In this article we review the evidence of predator pressure on great apes and specifically investigate the potential influence of predation‐risk on chimpanzee nesting behavior by comparing nests between chimpanzees living in a habitat of several potential predators (Issa, Ugalla, Tanzania) and a habitat relatively devoid of predators (Fongoli, Senegal). Chimpanzees in Issa did not nest more frequently in forest vegetation than chimpanzees in Fongoli although forest vegetation is expected to provide greater opportunity for escape from terrestrial predators. Nor do chimpanzees in Issa nest in larger groups or aggregate together more than Fongoli chimpanzees, as would be expected if larger groups provide protection from or greater detection of predators. Nests in Issa also did not appear to provide greater opportunities for escape than nests in Fongoli. Chimpanzees in Issa nested more frequently within the same tree as other community members, which may indicate that these chimpanzees nest in greater proximity than chimpanzees in Fongoli. Finally, Issa chimpanzees built their nests proportionately higher and more peripherally within trees. The selection of high and peripheral nesting locations within trees may make Issa chimpanzees inaccessible to potential predators. Many factors influence nest site selection in chimpanzees, of which danger from terrestrial predators is likely to be one. Am. J. Primatol. 75:593‐604, 2013. © 2013 Wiley Periodicals, Inc.
The Efficiency of the Metal Catalysts in the Nucleophilic Substitution of Alcohols is Dependent on the Nucleophile and Not on the Electrophile
Authors: Biswas Srijit , Samec Joseph S. M.
Published: March 2013

In this study, we investigate the effect of the electrophiles and the nucleophiles for eight catalysts in the catalytic SN1 type substitution of alcohols with different degree of activation by sulfur‐, carbon‐, oxygen‐, and nitrogen‐centered nucleophiles. The catalysts do not show any general variance in efficiency or selectivity with respect to the alcohols and follow the trend of alcohol reactivity. However, when it comes to the nucleophile, the eight catalysts show general and specific variances in the efficiency and selectivity to perform the desired substitution. Interestingly, the selectivity of the alcohols to produce the desired substitution products was found to be independent of the electrophilicity of the generated carbocations but highly dependent on the ease of formation of the cation. Catalysts based on iron(III), bismuth(III), and gold(III) show higher conversions for S‐, C‐, and N‐centered nucleophiles, and BiIII was the most efficient catalyst in all combinations. Catalysts based on rhenium(I) or rhenium(VII), palladium(II), and lanthanum(III) were the most efficient in performing the nucleophilic substitution on the various alcohols with the O‐centered nucleophiles. These catalysts generate the symmetrical ether as a by‐product from the reactions of S‐, C‐, and N‐centered nucleophiles as well, resulting in lower chemoselectivity.
Enhancing the Electrocatalytic Activity of Pt–Pd Catalysts by Introducing Porous Architectures
Authors: Niu Xiangheng , Zhao Hongli , Chen Chen , Lan Minbo
Published: March 2013

Improving the electrocatalytic activity of Pt‐based catalysts is of great importance for the development of heterogeneous catalysis, fuel cells, and analytical sensors. Herein, we achieve significant enhancement of the catalytic activity of Pt–Pd bimetallic materials towards glucose electrooxidation by introducing porous architectures with three‐dimensional dendritic microstructures, which were fabricated in situ on desired substrates through electrochemically reducing precursors along with periodic bubbling caused by the intermittent liberation of hydrogen. The synthesized Pt–Pd materials were characterized by SEM, nitrogen adsorption/desorption, energy dispersive spectroscopy, XRD, inductively coupled plasma optical emission spectrometry, and electrochemical techniques. Encouragingly, an extra‐large active surface area of up to 80.8 m2 g−1 was obtained for the porous Pt–Pd nanostructures, almost 3.8 times that of the Pt–Pd alloys prepared by standard electrodeposition techniques. As a result, the synthesized Pt–Pd with porous frameworks exhibited remarkably improved electrocatalytic properties for glucose oxidation in neutral media, with 1.5 times the mass activity compared to the conventional Pt–Pd structure. In addition, the porous Pt–Pd catalysts could be reused at least 100 times in the presence of chloride ions, with negligible loss of activity.
Gold(I)‐Catalyzed Domino Reaction of Allyl 2‐en‐4‐ynyl Ethers to 1,3,6‐Trien‐4‐yl Ketones
Authors: Hashmi A. Stephen K. , Graf Katharina , Ackermann Martin , Rominger Frank
Published: March 2013

The gold(I)‐catalyzed reaction of allyl 2‐en‐4‐ynyl ethers provides stereoselectively (Z)‐1,3,6‐trienes with an acyl substitutent in the 4‐position. The reaction proceeds through an oxygen transfer along the chain and a clean allylic inversion. This complements the preceding work by Gagosz, who obtained furan derivatives in his investigation of similar substrates with terminal alkynyl groups.10, 16 The only drawback of this mechanistically new pathway is the instability of the products under the reaction conditions, which sometimes prevents their isolation in high yields.
Superior Performance of Fe(BTC) With Respect to Other Metal‐Containing Solids in the N‐Hydroxyphthalimide‐Promoted Heterogeneous Aerobic Oxidation of Cycloalkanes
Authors: Mikami Yusuke , Dhakshinamoorthy Amarajothi , Alvaro Mercedes , Garcia Hermenegildo
Published: March 2013

A series of heterogeneous catalysts incorporating N‐hydroxyphthalimide (NHPI) and containing transition‐metal ion as promoter (Fe3+ or Co2+) on a support such as Fe(BTC) (BTC=1,3,5‐benzenetricarboxylate), zeolites Y and Beta, mesoporous Al‐MCM‐41 aluminosilicate, and nonporous silica have been prepared and tested for the aerobic oxidation of cyclooctane. It was found that NHPI/Fe(BTC) as catalyst exhibits the best performance in the series with the highest selectivity to the ‐ol/‐one mixture at identical conversions. These results have been interpreted as being due to the appropriate combination between reaction cavity dimensions and confinement of the autooxidation chain reaction. The catalytic activity for cyclohexane using NHPI/Fe(BTC) under similar reaction conditions is also reported.
Separation of Ethyl Acetate‐Dichloromethane‐Ethanol by Extractive Distillation: Simulation and Optimization
Authors: Wang H. , Cui X. , Li C. , Fang J.
Published: March 2013

Chemical process simulation software is adopted to simulate the separation of ethyl acetate‐dichloromethane‐ethanol and water with the aim to use water as the extraction solvent and to meet the requirement of reuse. The influences of solvent ratio, reflux ratio, theoretical plate number, feed position, and solvent position on separation efficiency are discussed. Optimization of orthogonal design and response surface are employed to further optimize the parameters. Relative experimental results prove the reliability of the simulation.
Numerical Simulation of Tube Erosion in a Bubbling Fluidized Bed with a Dense Tube Bundle
Authors: Liu Y. F. , Hinrichsen O.
Published: March 2013

Tube erosion in a bubbling fluidized bed is numerically studied using the Eulerian‐Eulerian method coupled with a monolayer kinetic energy dissipation model. The hydrodynamical simulations are performed under conditions with three different superficial gas velocities. The time‐averaged bubble frequency and bubble rise velocity are calculated to characterize the bed hydrodynamics. The erosion rates of two target tubes are simulated and the influence of the bubble behaviors on erosion rates is evaluated. Compared with the experimental data in the literature, the bubble behaviors are well captured by the simulations. Good agreement between the calculated and measured erosion rates is also obtained for the two target tubes. The bubble behaviors around the tubes have direct impact on the tube erosion. Only small discrepancies in the calculated erosion rates are found when using different particle‐wall restitution coefficients and specularity coefficients.
Effect of Nickel Addition on Ceria‐Supported Platinum Catalysts for Medium‐Temperature Shift Reaction in Fuel Processors
Authors: Alijani A. , Irankhah A.
Published: March 2013

Medium‐temperature shift reaction (MTS, 280–340 °C) has received much attention for use in fuel processors. In this study, bifunctional Pt‐Ni/CeO2 catalysts were prepared by different Pt (0.1–0.5 %) and Ni (5–20 %) loadings, and investigated for MTS reaction. X‐ray diffraction, N2 adsorption and temperature‐programmed reduction tests were used to characterize the prepared samples. The results showed that Pt‐Ni bimetallic catalysts have higher CO conversion in comparison to Pt/CeO2 monometallic catalyst. Furthermore, the sequential synthesis method of Pt and Ni impregnation was preferred to the simultaneous one, which is due to the better Pt dispersion on catalytic surface. Steam to carbon ratio variations study showed the maximum CO conversion to be in the range of 4.5.
Water‐Free Rare‐Earth‐Metal Ionic Liquids/Ionic Liquid Crystals Based on Hexanitratolanthanate(III) Anion
Authors: Ji Shun‐Ping , Tang Meng , He Ling , Tao Guo‐Hong
Published: March 2013

The hexanitratolanthanate anion (La(NO3)63−) is an interesting symmetric anion suitable to construct the component of water‐free rare‐earth‐metal ionic liquids. The syntheses and structural characterization of eleven lanthanum nitrate complexes, [Cnmim]3[La(NO3)6] (n=1, 2, 4, 6, 8, 12, 14, 16, 18), including 1,3‐dimethylimidazolium hexanitratolanthanate ([C1mim]3[La(NO3)6], 1), 1‐ethyl‐3‐methylimidazolium hexanitratolanthanate ([C2mim]3[La(NO3)6], 2), 1‐butyl‐3‐methylimidazolium hexanitratolanthanate ([C4mim]3[La(NO3)6], 3), 1‐isobutyl‐3‐methylimidazolium hexanetratolanthanate ([isoC4mim]3[La(NO3)6], 4), 1‐methyl‐3‐(3′‐methylbutyl)imidazolium hexanitratolanthanate ([MC4mim]3[La(NO3)6], 5), 1‐hexyl‐3‐methylimidazolium hexanitratolanthanate ([C6mim]3[La(NO3)6], 6), 1‐methyl‐3‐octylimidazolium hexanitratolanthanate ([C8mim]3[La(NO3)6], 7), 1‐dodecyl‐3‐methylimidazolium hexanitratolanthanate ([C12mim]3[La(NO3)6], 8), 1‐methyl‐3‐tetradecylimidazolium hexanitratolanthanate ([C14mim]3[La‐(NO3)6], 9), 1‐hexadecyl‐3‐methylimid‐azolium hexanitratolanthanum ([C16dmim]3[La(NO3)6], 10), and 1‐methyl‐3‐octadecylimidazolium hexanitratolanthanate ([C18mim]3[La(NO3)6], 11) are reported. All new compounds were characterized by 1H and 13C NMR, and IR spectroscopy as well as elemental analysis. The crystal structure of compound 1 was determined by using single‐crystal X‐ray diffraction, giving the following crystallographic information: monoclinic; P21/c; a=15.3170 (3), b=14.2340 (2), c=13.8954(2) Å; β=94.3453(15)°, V=3020.80(9) Å3, Z=4, ρ=1.764 g cm−3. The coordination polyhedron around the lanthanum ion is rationalized by six nitrate anions with twelve oxygen atoms. No hydrogen‐bonding network or water molecule was found in 1. The thermodynamic stability of the new complexes was investigated by using thermogravimetric analysis (TGA). The water‐free hexanitratolanthanate ionic liquids are thermal and moisture stable. Four complexes, namely complexes 8–11, were found to be ionic liquid crystals by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). They all present smectic A liquid‐crystalline phase.
ChemInform Abstract: Woollins Reagent: A Chemoselective Reducing Agent for 1,4‐Enediones and 1,4‐Ynediones to Saturated 1,4‐Diones.
Authors: Mandal Madhumita , Chatterjee Sourav , Jaisankar Parasuraman
Published: March 2013

The reduction of C‐C multiple bonds in the presence of a carbonyl group proceeds selectively using Woollins reagent and methanol as the proton source.
Process Intensification in the Gas Phase Conversion of Dimethyl Maleate to Tetrahydrofuran
Authors: Marz Stefan , Müller Steffen Peter , Kraushaar‐Czarnetzki Bettina
Published: March 2013

Durch die Verwendung eines bifunktionellen Cu/ZnO/γ‐Al2O3‐Katalysators ist es möglich, die normalerweise mehrstufige Gasphasenumsetzung von Dimethylmaleat (DMM) zu Tetrahydrofuran (THF) in einem einzigen Festbettreaktor mit einer THF‐Ausbeute von nahezu 100 % durchzuführen. Die Raum‐Zeit‐Ausbeute an THF wird durch das Zulaufverhältnis H2/DMM kaum beeinflusst, lässt sich aber durch Erhöhung des Totaldrucks und insbesondere der Temperatur erheblich steigern.
Photodissociation of ClNO in the 2 1A′ State: Computational and Experimental NO Product State Distributions
Authors: Jones Kiera M. , Milkiewicz Jadwiga A. , Whitaker Benjamin J. , Sage Alan G. , Worth Graham A.
Published: March 2013

Ultrafast photodissociation of the 2 1A′ state of ClNO, which has an absorption spectrum peaking at 335 nm, is studied by computational and experimental methods. New potential‐energy surfaces are calculated for the 1 and 2 1A′ states at the multireference configuration interaction (MRCI) level. Wavepacket dynamics simulations performed both exactly and by using the multiconfiguration time‐dependent Hartree method yield essentially identical results. Transition dipole moments at a range of geometries are included in these calculations to correctly model the excitation. Vibrational and rotational state distributions of the NO product are obtained both computationally by analysing the quantum flux on the 2 1A′ surface and experimentally by use of 3D resonant multiphoton ionisation (REMPI), a variant of the velocity map imaging technique. The nascent NO is found to be only marginally vibrationally excited, with 91 % formed in v=0. The calculated NO rotational distribution peaks in the j=45–55 region, which compares favourably to experiment.
Oxygen‐Functionalized Few‐Layer Graphene Sheets as Active Catalysts for Oxidative Dehydrogenation Reactions
Authors: Schwartz Viviane , Fu Wujun , Tsai Yu‐Tung , Meyer Harry M. , Rondinone Adam J. , Chen Jihua , Wu Zili , Overbury Steven H. , Liang Chengdu
Published: March 2013

Nanostructured graphitic forms of carbons have shown intersting potential for catalysis research and are ideal candidates to substitute the conventional metal‐oxide catalysts because they can be easily disposed, which enables a greener, more sustainable catalytic process. Few‐layer graphene and its functionalized form offer the opportunity to investigate the nature of graphitic active sites for oxidation reactions in well‐defined carbon‐based catalysts. In this paper, we report the utilization of oxygen‐functionalized few‐layer graphene sheets containing variable amounts of oxygen in the heterogeneous catalytic oxidative dehydrogenation (ODH) reaction of isobutane at 400ºC. Interestingly, there is poor correlation between oxygen content and catalytic performance. Carbonyl groups were found to be highly stable, and graphene that had higher sp2character, the lowest oxygen content, and fewer edge sites presented the lowest specific rate of isobutane reaction, although the isobutene selectivity remained high. The reoxidation of the graphene surface occurred at the same rate as the ODH reaction suggesting a Mars–van Krevelen type of mechanism, similar to that which takes place on oxide surfaces. These results appear to suggest that a higher fraction of exposed edges where oxygen active sites can be formed and exchanged should lead to more active catalysts for ODH reactions.
Long‐term, inducible gene loss‐of‐function in the chicken embryo
Authors: Serralbo Olivier , Picard Cyril A. , Marcelle Christophe
Published: March 2013

The use of shRNAmir to down‐regulate the expression of genes of interest is a powerful tool for studying gene function during early chick development. However, because of the limitations of electroporation‐mediated transgenesis, the down‐regulation of genes expressed at late stages of development in specific tissues is difficult to perform. By combining electroporation of a doxycycline‐inducible, miR30‐based shRNA plasmid with the Tol2 genomic integration system, we are now able to down‐regulate the expression of any gene of interest at defined stage of chicken development. genesis 51:372–380. © 2013 Wiley Periodicals, Inc.
Commentary on ‘Social skills groups for people aged 6 to 21 with autism spectrum disorders (ASD)’
Authors: Gillies Donna , Carroll Louisa , Loos Melissa
Published: March 2013

This is a commentary on a Cochrane review, published in this issue of EBCH, first published as: Reichow B, Steiner AM, Volkmar F. Social skills groups for people aged 6 to 21 with autism spectrum disorders (ASD). Cochrane Database of Systematic Reviews 2012, Issue 7. Art. No.: CD008511. DOI: 10.1002/14651858.CD008511.pub2.

Further information for this Cochrane review is available in this issue of EBCH in the accompanying Summary article.
Commentary on ‘Interventions for restoring patency of central venous catheter lumens’
Authors: Bauman Mary Elisabeth , Massicotte Mary Patricia
Published: March 2013

This is a commentary on a Cochrane review, published in this issue of EBCH, first published as: van Miert C, Hill R, Jones L. Interventions for restoring patency of occluded central venous catheter lumens. Cochrane Database of Systematic Reviews 2012, Issue 4. Art. No.: CD007119. DoI: 10.1002/14651858.CD007119.pub2.

Further information for this Cochrane review is available in this issue of EBCH in the accompanying Summary article.
Systematic reviews of bruising in relation to child abuse—what have we learnt: an overview of review updates
Authors: Maguire Sabine , Mann Mala
Published: March 2013

Background:

Dogma has long prevailed regarding the ageing of bruises, and whether certain patterns of bruising are suggestive or diagnostic of child abuse.

Objectives:

We conducted the first Systematic Reviews addressing these two issues, to determine the scientific basis for current clinical practice. There have been seven updates since 2004.

Methods:

An all language literature search was performed across 13 databases, 1951–2004, using >60 key words, supplemented by ‘snowballing’ techniques. Quality standards included a novel confirmation of abuse scale. Updates used expanded key words, and a higher standard for confirmation of abuse.

Results:

Of 1495 potential studies, only three met the inclusion criteria for ageing of bruises in 2004, confirming that it is inaccurate to do so with the naked eye. This was roundly rejected when first reported, generating a wave of new studies attempting to determine a scientifically valid method to age bruises, none of which are applicable in children yet. Regarding patterns of bruising that may be suggestive or diagnostic of abuse, we included 23 of 167 studies reviewed in 2004, although only 2 were comparative studies. Included studies noted that unintentional bruises occur predominantly on the front of the body, over bony prominences and their presence is directly correlated to the child's level of independent mobility. Bruising patterns in abused children, differed in location (most common site being face, neck, ear, head, trunk, buttocks, arms), and tended to be larger. Updates have included a further 14 studies, including bruising in disabled children, defining distinguishing patterns in severely injured abused and non‐abused children, and importance of petechiae.

Conclusions:

Systematic Reviews of bruising challenged accepted wisdom regarding ageing of bruises, which had no scientific basis; stimulated higher quality research on patterns of bruises distinguishing abusive and non‐abusive bruising patterns, and highlighted the benefits of regular updates of these reviews.
The cytotoxicity of fatty acid/α‐lactalbumin complexes depends on the amount and type of fatty acid
Authors: Brinkmann Christel Rothe , Brodkorb André , Thiel Steffen , Kehoe Joseph J.
Published: March 2013

Complexes of the milk protein, α‐lactalbumin, and the fatty acid, oleic acid, have previously been shown to be cytotoxic. Complexes of α‐lactalbumin and five different fatty acids (vaccenic, linoleic, palmitoleic, stearic, and elaidic acid) were prepared and compared to those formed with oleic acid. All complexes were cytotoxic to human promyelocytic leukemia‐derived (HL‐60) cells but to different degrees depending on the fatty acid. The amount of fatty acid per α‐lactalbumin molecule was found to correlate with the cytotoxicity; the higher the number of fatty acids per protein, the more cytotoxic the complex. Importantly, all the tested fatty acids were also found to be cytotoxic on their own in a concentration dependent manner. The cytotoxic effect of complexes between α‐lactalbumin and linoleic acid, vaccenic acid, or oleic acid was further investigated using flow cytometry and found to induce cell death resembling apoptosis on Jurkat cells.

Practical applications: Cytotoxic complexes of α‐lactalbumin and several different fatty acids could be produced. The cytotoxicity of all the variants is similar to that previously determined for α‐lactalbumin/oleic acid complexes.
Towards the Total Synthesis of Pl‐3: Preparation of the Eastern Fragment through a Diastereoselective SmI2‐Mediated Reformatsky Reaction
Authors: Fürst Rita , Lentsch Christoph , Rinner Uwe
Published: March 2013

The jatrophane diterpene Pl‐3, isolated in 2003 from Euphorbia platyphyllos, is a structurally complex natural product with highly promising biological properties that include pronounced antiproliferative activity and the inhibition of the efflux‐pump activity of multidrug resistance p‐glycoprotein. Herein, the synthesis of the eastern fragment of Pl‐3 is outlined. The target compound is synthesized in nine synthetic operations in good overall yield, starting from readily available D‐ribose. The key step in the preparation of the eastern part of Pl‐3 is a diastereoselective SmI2‐mediated Reformatsky reaction. The proposed route is highly flexible and could also be applied to the synthesis of structurally related jatrophane diterpenes.
A quasi‐dynamic procedure for coupled thermal simulations
Authors: Errera Marc‐Paul , Baqué Bénédicte
Published: March 2013

This paper outlines the development and adaptation of a coupling strategy for transient temperature analysis in a solid via a conjugate heat transfer method. This study proposes a quasi‐dynamic coupling procedure to bridge the temporal disparities between the fluid and the solid. In this approach, dynamic thermal modeling in the solid is coupled with a sequence of steady states in the fluid. This quasi‐dynamic algorithm has been applied to the problem of convective heat transfer over, and transient conduction heat transfer within, a flat plate using the severe thermal conditions of a solid propellant rocket. Two different coupled thermal computations have been performed. In the first one—referred to as the reference computation—the coupling period is equal to the smallest solid time constant. In the second one, a very large coupling period is used. The results show that the procedure can predict accurate transient temperature fields at a reasonable computational cost. The simulation CPU time is approximately reduced by up to 90%, while maintaining a very good accuracy. All the details of the numerical test case are given in the paper. This application illustrates the capabilities and the overall efficiency of this coupled approach in a solid transient problem using long term simulations of time dependent flows. Copyright © 2013 John Wiley & Sons, Ltd.
Royal jelly enhances antigen‐specific mucosal IgA response
Authors: Kai Hikaru , Motomura Yuji , Saito Shiro , Hashimoto Ken , Tatefuji Tomoki , Takamune Nobutoki , Misumi Shogo
Published: March 2013

The effective uptake of antigens (Ags) by specialized M cells of gut‐associated lymphoid tissues is an important step in inducing an efficient intestinal mucosal immune response. In this study, royal jelly (RJ) was found to stimulate the differentiation of M‐like cells from human Caco‐2 cells in an in vitro M cell model. Furthermore, RJ and protease‐treated royal jelly (pRJ) efficiently enhanced transcytosis of FluoSpheres® carboxylate‐modified microspheres from the apical side to the basolateral side in the model. Therefore, we evaluated the ability of pRJ to induce efficient mucosal immune responses in an in vivo nonhuman primate. Continuous oral administration of commercially available pRJ resulted in a significant enhacement of the antigen‐specific IgA response in stool sample. Interestingly, Caco‐2 monolayer assay demonstrated that ether extracts from pRJ efficiently increased the expression level of a universal M cell marker, glycoprotein 2 (gp2). These findings suggest that pRJ exhibits mucosal immunomodulatory properties via stimulation of effective uptake of Ags through M cells.