bluuebunny/crossref_metadata_2025 huggingface dataset:
Definición y unidades de las constantes de equilibrio en los libros de texto de Química general preuniversitarios y universitarios
Authors: Quílez-Pardo Juan , Quílez-Díaz Ana
Published: November 2014

En este trabajo, una vez definidas las constantes de equilibrio experimentales, Kp y Kc, así como la constante de equilibrio termodinámica, Kº, se analiza su incorrecto tratamiento por parte de libros de texto de química general. Se expone la forma en que libros de química general de universidad y de bachillerato manejan las unidades de las constantes de equilibrio. Muchos textos no expresan con unidades los valores de Kp y Kc calculados. Además, en la mayoría de los casos, Kº no se define, y como resultado existe una confusión muy extendida acerca de estos conceptos. Este problema terminológico ocasiona que en muchos libros se confunda Kp con Kº. Se propone que la definición correcta de las constantes Kp y Kc se realice en el nivel preuniversitario, dejando para el primer curso universitario de química general la definición de la constante de equilibrio termodinámica, Kº, así como su relación con Kp y Kc.
¿Cómo mejorar la educación científica de Primaria en España desde el currículo oficial? Sugerencias a partir de un análisis curricular comparativo en torno a las finalidades y contenidos de la Ciencia escolar
Authors: Criado García-Legaz Ana M. , Cruz-Guzmán Marta
Published: November 2014

Se compara el currículo de ciencias español en educación primaria (enseñanzas mínimas nacionales) con los de Inglaterra y EE. UU., y se hacen propuestas de mejora. En las finalidades proponemos la inclusión de nociones de naturaleza de la ciencia y énfasis en la ciencia recreativa. Para los contenidos, sugerimos una revisión general por un panel de expertos en cada una de las materias de ciencias y su didáctica, una mayor sistematización de cada contenido a lo largo de los tres ciclos y una mejor articulación de los contenidos con el resto de diferentes elementos curriculares.
Acercar la geodiversidad a través de las salidas de campo en la ESO. Una investigación con el profesorado de ciencias de Bizkaia
Authors: Zamalloa Echevarría Teresa , Sanz Alonso Josu , Maguregi González Gurutze , Fernández Alonso Mª Dolores , Echevarría Ugarte Isabel
Published: November 2014

El presente trabajo explora el perfil académico y la actitud sobre la geología/geodiversidad del profesorado de ciencias de la ESO, analizando las dificultades que retraen a los docentes de realizar salidas de campo y recogiendo las claves positivas de los que sí las realizan. Un estudio llevado a cabo en el territorio histórico de Bizkaia en el que han participado un total de 84 docentes. A través de encuestas y entrevistas, y partiendo de la necesidad de integrar la geodiversidad en el currículo educativo, este proyecto quiere servir, además, para un mayor aprovechamiento de las zonas de alto interés geológico.
Naturaleza de la ciencia en notícias científicas de la prensa: análisis del contenido y potencialidades didácticas
Authors: García-Carmona Antonio
Published: November 2014

Se destaca el potencial didáctico de ciertas noticias científicas de la prensa diaria para introducir la naturaleza de la ciencia (NDC) en la educación científica. A fin de ponerlo de manifiesto, se analiza interpretativamente el contenido de un repertorio de cuarenta noticias relacionadas con la Física, publicadas en periódicos españoles de gran difusión. El análisis revela la idoneidad del repertorio, tanto por la sintonía de su contenido con la visión actual de la NDC como por las posibilidades didácticas para su uso en el aula, de acuerdo con las tendencias actuales en la enseñanza de esta. Se sugiere, asimismo, su utilización en los programas de formación del profesorado, a fin de mejorar su comprensión sobre la NDC y, consecuentemente, su enseñanza.
El desarrollo de la competencia científica en una unidad didáctica sobre la salud bucodental. Diseño y análisis de tareas
Authors: Franco Mariscal Antonio Joaquin , Blanco López Ángel , España Ramos Enrique
Published: November 2014

En este artículo se plantea la importancia del diseño de los materiales curriculares para el desarrollo de la competencia científica. Para ello, se hace especial énfasis en la necesidad de partir de un enfoque explícito y claramente formulado sobre cómo entender esta competencia y de vincular las tareas y actividades de aprendizaje con dicho enfoque. Se muestra el análisis pormenorizado de la contribución al desarrollo de esta competencia, según uno de los enfoques planteados en la bibliografía, de algunas de las tareas de aprendizaje incluidas en una unidad didáctica sobre la salud bucodental para 4.º de ESO. Finalmente, se hacen algunas consideraciones sobre la importancia del diseño y el análisis de tareas, y la necesidad de su inclusión en la formación del profesorado de ciencia.
Determinación de una controversia socio-científica a nivel local: el caso del agua como recurso natural en prensa
Authors: Díaz Moreno Naira Concepción
Published: November 2014

Las controversias sociocientíficas surgen y nos rodean en los temas más actuales y emergentes como transgénicos, homeopatía, etc. Dada la importancia que tienen las controversias en las últimas propuestas educativas (Sadler y Zeidler, 2009), esta tesis doctoral está centrada en el estudio de indicadores para determinar controversias sociocientíficas en prensa que puedan servir a los profesores para su uso en el aula de ciencias. La percepción de déficit hídrico existente en Almería en oposición a la alta demanda de agua por parte de la agricultura y el reconocimiento como problema ambiental relevante, según los datos del Ecobarómetro junto con la implantación de la Directiva Marco Agua y el debate creado con la derogación del PHN y el trasvase del Ebro en el 2004, justifican la elección como controversia que cabe estudiar.
Cambio en las concepciones de los docentes sobre la argumentación y su desarrollo en clase de ciencias
Authors: Ruiz Ortega Francisco Javier , Márquez Bargalló Conxita , Tamayo Alzate Oscar Eugenio
Published: November 2014

Este estudio muestra los cambios en las concepciones sobre los aspectos epistemológicos, conceptuales, didácticos y sobre la estructura argumentativa de cinco maestros de educación primaria que participaron en un proceso de reflexión crítica sobre la argumentación y su desarrollo en clase de ciencias. Con el fin de obtener información para su análisis e identificación de los cambios en los cuatro aspectos antes mencionados, se aplicó al inicio y final del proceso un cuestionario. Los resultados mostraron un cambio significativo en los componentes: epistemológico, conceptual y educativo, y no tanto en el estructural. Con dichos resultados se ratificó la importancia de ofrecer espacios de participación de los profesores para discutir, evaluar y proponer mecanismos de mejora en sus prácticas docentes en el aula.
Appropriate Pricing Policy Needed Worldwide for Improving Water Services Infrastructure
Authors: Hukka Jarmo J. , Katko Tapio S.
Published: November 2014

This article highlights the enormous and growing gap between the projected and required financing of water services infrastructure, which is caused by unviable pricing and/or cost‐recovery regimes. Globally there is a growing funding gap in rehabilitation, renewal, and replacement of aging water infrastructure and the need for future greenfield investments. Underpricing of water services and the need for rehabilitation seem to be worldwide phenomena. There are diverse constraints in OECD (Organisation for Economic Co‐Operation and Development) and non‐OECD countries contributing to underpriced water services; however, the message is clear: the global water industry must stop underpricing precious water resources. Future enjoyment of sustainable water services will require customers to bear all or at least a major part of the costs. Better awareness of broader economic and social benefits of water supply, and particularly of sanitation, also will be needed.
Evaluation of the Final UCMR2 Database: Nationwide Trends in NDMA
Authors: Woods Gwen C. , Dickenson Eric R. V.
Published: November 2014

The complete database of results from the second Unregulated Contaminant Monitoring Rule (UCMR2) was analyzed in depth for N‐nitrosodimethylamine (NDMA) occurrence across the United States and analyzed for trends associated with factors reported. Disinfectant type, source waters, regional variability, population density, and seasonal variability were all examined for potential impacts on NDMA. Detectable levels of NDMA were found in 17% of samples and 25% of treatment plants. The other five listed nitrosamines were detected in less than 1% of samples. The strongest factor found positively associated with NDMA occurrence was chloramine use. Likewise, the use of surface waters was found to be linked to NDMA occurrence such that surface waters (even when decoupled from chloramine use) demonstrated elevated levels of NDMA over groundwater sources. No clear seasonal trends could be deciphered, but data supplied from utilities servicing fewer than 10,000 customers provide evidence that smaller utilities have some of the most extreme NDMA levels and subsequently may have a difficult time meeting any future NDMA regulation.
Lis1 regulates dynein by sterically blocking its mechanochemical cycle
Authors: Toropova Katerina , Zou Sirui , Roberts Anthony J , Redwine William B , Goodman Brian S , Reck-Peterson Samara L , Leschziner Andres E
Published: November 2014

Regulation of cytoplasmic dynein's motor activity is essential for diverse eukaryotic functions, including cell division, intracellular transport, and brain development. The dynein regulator Lis1 is known to keep dynein bound to microtubules; however, how this is accomplished mechanistically remains unknown. We have used three-dimensional electron microscopy, single-molecule imaging, biochemistry, and in vivo assays to help establish this mechanism. The three-dimensional structure of the dynein–Lis1 complex shows that binding of Lis1 to dynein's AAA+ ring sterically prevents dynein's main mechanical element, the ‘linker’, from completing its normal conformational cycle. Single-molecule experiments show that eliminating this block by shortening the linker to a point where it can physically bypass Lis1 renders single dynein motors insensitive to regulation by Lis1. Our data reveal that Lis1 keeps dynein in a persistent microtubule-bound state by directly blocking the progression of its mechanochemical cycle.
Modification of the loss cone for energetic particles
Authors: Porazik Peter , Johnson Jay R. , Kaganovich Igor , Sanchez Ennio
Published: November 2014

The optimal pitch angle which maximizes the penetration distance, along the magnetic field, of relativistic charged particles injected from the midplane of an axisymmetric field is investigated analytically and numerically. Higher‐order terms of the magnetic moment invariant are necessary to correctly determine the mirror point of trapped energetic particles, and therefore the loss cone. The modified loss cone resulting from the inclusion of higher‐order terms is no longer entirely defined by the pitch angle but also by the phase angle of the particle at the point of injection. The optimal orientation of the injection has a nonzero component perpendicular to the magnetic field line, and is in the plane tangential to the flux surface. Numerical integration of particle orbits were carried out for a relativistic electron in a dipole field, showing agreement with analytic expressions. The results are relevant to experiments, which are concerned with injection of relativistic beams into the atmosphere from aboard a spacecraft in the magnetosphere.
Trend and interannual variability in southeast Greenland Sea Ice: Impacts on coastal Greenland climate variability
Authors: Moore G. W. K. , Straneo F. , Oltmanns M.
Published: November 2014

We describe the recent occurrence of a region of diminished sea ice cover or “notch” offshore of the Kangerdlugssuaq Fiord, the site of the largest tidewater glacier along Greenland's southeast coast. The notch's location is consistent with a topographically forced flux of warm water toward the fiord, and the decrease of the sea ice cover is shown to be associated with a regional warming of the upper ocean that began in the mid‐1990s. Sea ice in the vicinity of the notch also exhibits interannual variability that is shown to be associated with a seesaw in surface temperature and sea ice between southeast and northeast Greenland that is not describable solely in terms of the North Atlantic Oscillation. We therefore argue that other modes of atmospheric variability, including the Lofoten Low, are required to fully document the changes to the climate that are occurring along Greenland's east coast.
Vertical velocities and turbulence in midlatitude anvil cirrus: A comparison between in situ aircraft measurements and ground‐based Doppler cloud radar retrievals
Authors: Muhlbauer Andreas , Kalesse Heike , Kollias Pavlos
Published: November 2014

This study introduces a statistical comparison of vertical velocity observations within cirrus from aircraft and ground‐based Doppler cloud radar. Two cases of midlatitude anvil cirrus forming under very similar environmental conditions are examined. The case studies benefit from simultaneous observations of vertical velocities in cirrus collected at and around the Atmospheric Radiation Measurement Southern Great Plains site during the U.S. Department of Energy Small Particles in Cirrus field campaign. Observations from both platforms suggest that the majority of vertical velocities in the examined midlatitude anvil cirrus cases are roughly within ±1 m s−1 although higher vertical velocities are occasionally observed. The quality of the vertical velocity comparison between in situ aircraft measurements and ground‐based Doppler radar retrievals depends on the case. For the first case on 23 April 2010, the comparison suggests that the radar retrieval may underestimate vertical velocities in the range between roughly 50 cm s−1 and 1 m s−1. For the second case on 14 June 2010, the agreement between radar and aircraft is excellent, and the differences are largely within the observed variability of vertical velocities within cirrus. Differences in the spatial scales of vertical velocities and turbulence sampled by the aircraft and Doppler radar, which arise due to differences in the temporal resolution of the observational platforms are not found to explain the observed discrepancies. Estimates for the dissipation rate of turbulent kinetic energy agree to within 1 order of magnitude between the two observational platforms.
An empirical model of the occurrence of an additional layer in the ionosphere from the occultation technique: Preliminary results
Authors: Zhao Biqiang , Zhu J. , Xiong B. , Yue X. , Zhang M. , Wang M. , Wan W.
Published: November 2014

About 8 year electron density profile (EDP) data from the COSMIC/FORMOSAT‐3 satellites radio occultation technique were used to investigate the additional stratification of the F2 (the so‐called F3 layer) layer over the equatorial and low‐latitude ionosphere on a global scale for both the bottomside and topside ionosphere. The F3 layer was recognized through the altitude differential profile featured by two maxima existing from the selected EDP profile. There were ~37,000 (bottomside) and 25,000 (topside) cases of F3 layer selected out of ~1.27 million occultation events at equatorial and low‐latitude areas during the period of April 2006 to August 2014. The statistical results for the bottomside ionosphere resemble that reported in Zhao et al. (2011a), while in the topside the highest occurrence of F3 layer shows a 3–4 h delay depending on the altitude range of the stratification. The magnetic latitude distribution shows different dependence with a tendency to form a single crest toward high altitude. Also, the seasonal variation is weaker in the topside ionosphere compared to the bottomside one, especially in the high altitude. Then we build up an empirical model of the F3 layer occurrence using the bottomside statistics based on empirical orthogonal function (EOF) decomposition as it gets the inherent characters inside the data set and converges quickly. The model well grasps the main features of the F3 occurrence, e.g., the F3 occurrence's sensitivity on the magnetic latitude. Further, in order to accommodate the ground observation a corrected factor was introduced. As F3 layer is an important phenomenon in the low‐latitude ionosphere, we have made an attempt to describe its feature with a consecutive function although future work needs to be done for an overall expression of this structure.
Hot magnetospheric O+ and cold ion behavior in magnetopause reconnection: Cluster observations
Authors: Wang S. , Kistler L. M. , Mouikis C. G. , Liu Y. , Genestreti K. J.
Published: November 2014

In reconnection, the presence of heavy ions like O+ increases the ion mass density reducing the fluid's Alfvén speed. In addition, it may modify the reconnection structure, which can also change the reconnection rate. However, because O+ ions have a larger Larmor radii than H+ ions at the same velocity, they may not be fully entrained in the reconnection flow and may have kinetic effects other than just increasing the mass density. In this study, for the first time, the ion velocity distribution functions of H+ and O+ from one magnetopause reconnection event with a strong guide field are analyzed to determine in detail the behavior of the different ion populations. We show that the hot magnetospheric O+ ions, along with the hot magnetospheric H+ ions almost fully participate in the reconnection exhaust flows. Finite Larmor radius effects are also apparent and control how far the ions extend on the magnetosheath side. Ion signatures consistent with heating after being picked up in the reconnection exhaust flow are observed in the H+ and O+ distribution functions. The dynamics of the cold magnetospheric ions depends on where they enter the reconnection region. If they enter the reconnection region at the downstream separatrix, they will be taken away by the magnetic field in an adiabatic way as analyzed by Drake et al. (2009a); if they enter close to the diffusion region, they behave as pick‐up ions.
Observation of a retreating x line and magnetic islands poleward of the cusp during northward interplanetary magnetic field conditions
Authors: Wilder F. D. , Eriksson S. , Trattner K. J. , Cassak P. A. , Fuselier S. A. , Lybekk B.
Published: November 2014

When the interplanetary magnetic field is northward, reconnection occurs in each hemisphere on lobe field lines, poleward of the cusp. We have identified a case where the Cluster spacecraft crossed the magnetopause and encountered a tailward retreating x line. The x line is identified by the encounter of both a tailward and sunward jet, as well as Hall magnetic field signatures in the out‐of‐plane direction. Additionally, we find no signatures of electron heating and hypothesize that the spacecraft is too close to the x line to observe the accelerated electrons. Using two spacecraft, we are able to resolve the velocity of the structure, which moves near the magnetosheath speed. The speed of the x line is also consistent with the asymmetric reconnection theory. To our knowledge, this is the first time the speed of a retreating x line has been measured directly. Additionally, we observe ion distribution functions with counterstreaming populations, suggesting that a second x line formed sunward of the original one, leading to a magnetic island.
Ion composition in interchange injection events in Saturn's magnetosphere
Authors: Thomsen M. F. , Reisenfeld D. B. , Wilson R. J. , Andriopoulou M. , Crary F. J. , Hospodarsky G. B. , Jackman C. M. , Jia X. , Khurana K. K. , Paranicas C. , Roussos E. , Sergis N. , Tokar R. L.
Published: November 2014

Interchange injection events are commonly observed by the Cassini spacecraft in the region between about 6 and 12 Rs (1 Rs = 60,268 km) and even frequently beyond. In this study, 13 examples of interchange injection events are identified in Cassini/Cassini Plasma Spectrometer data under special conditions such that time‐of‐flight (TOF) mass spectra could be obtained from entirely within the events. Using the TOF data to separate the main ion species H+, H2+, and W+, approximate densities of each species are calculated under the assumption that all distributions were isotropic. The light‐ion density ratios, H2+/H+, in the injection events are not discernibly different from those ratios in control intervals from the ambient plasma. However, the water‐group ratio, W+/H+, is significantly lower than ambient. The comparison of the measured density ratios with the range of values observed throughout Saturn's magnetosphere indicates that the values of W+/H+ that are as low as those observed within the injection events are found primarily beyond L~14 (where L is the equatorial crossing distance, in Saturn radius, of a dipole field line), indicating that the injection events are delivering plasma from the outer magnetosphere at times traveling at least 6 Rs.
3D Hierarchical Porous α‐Fe2O3 Nanosheets for High‐Performance Lithium‐Ion Batteries
Authors: Cao Kangzhe , Jiao Lifang , Liu Huiqiao , Liu Yongchang , Wang Yijing , Guo Zaiping , Yuan Huatang
Published: November 2014

To develop a long cycle life and good rate capability electrode, 3D hierarchical porous α‐Fe2O3 nanosheets are fabricated on copper foil and directly used as binder‐free anode for lithium‐ion batteries. This electrode exhibits a high reversible capacity and excellent rate capability. A reversible capacity up to 877.7 mAh g−1 is maintained at 2 C (2.01 A g−1) after 1000 cycles, and even when the current is increased to 20 C (20.1 A g−1), a capacity of 433 mA h g−1 is retained. The unique porous 3D hierarchical nanostructure improves electronic–ionic transport, mitigates the internal mechanical stress induced by the volume variations of the electrode upon cycling, and forms a 3D conductive network during cycling. No addition of any electrochemically inactive conductive agents or polymer binders is required. Therefore, binder‐free electrodes further avoid the uneven distribution of conductive carbon on the current collector due to physical mixing and the addition of an insulator (binder), which has benefits leading to outstanding electrochemical performance.
Analysis of mass transfer in a corotating disks catalytic reactor
Authors: Gonzalez‐Hidalgo Clara‐Tatiana , Herrero Joan , Puigjaner Dolors
Published: November 2014

The flow and mass transfer in a discontinuous reactor configuration consisting of a pair of corotating enclosed disks with a chemical reaction taking place at the disk surfaces have been analyzed. The calculated mass‐transfer efficiencies do not follow the expected
dependence because the overall mass‐transfer process is not boundary‐layer controlled, especially at high Schmidt numbers. It has been found in all of the cases investigated that despite the fact that the reactant concentration is continuously dropping with time its spatial distribution, relative to the volume‐averaged value, becomes stationary after a short initial transient. This result implies that the mass‐transfer efficiency in the discontinuous reactor also becomes stationary and the resulting time‐independent value,
, obtained either directly from calculation or from the fit of the collected results, provides a fairly good estimate of the reactor operation time needed to achieve the target reactant conversion. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1015–1031, 2015
Ion‐exchange adsorption of calcium ions from water and geothermal water with modified zeolite A
Authors: Song Junchao , Liu Mingyan , Zhang Yang
Published: November 2014

The modified zeolite A was prepared by a two‐step crystallization method to remove scale‐forming cations from water and geothermal water. The adsorption kinetics, mechanism and thermodynamics were studied. The calcium ion adsorption capacity of the modified zeolite A was 129.3 mg/g (1 mg/g = 10−3 kg/kg) at 298 K. The adsorption rate was fitted well with pseudo‐second‐order rate model. The adsorption process was controlled by film diffusion at the calcium ion concentration less than 250 mg/L (1 mg/L = 10−3 kg/m3), and it was controlled by intraparticle diffusion at the concentration larger than 250 mg/L. The calculated mass‐transfer coefficient ranged from 2.23 × 10−5 to 2.80 × 10−4cm/s (1 cm/s = 10−2m/s). Dubinin–Astakhov isotherm model could appropriately describe the adsorption thermodynamic properties when combined with Langmuir model. The adsorption process included not only ion exchange but also complexation between calcium and hydroxyl ions. The adsorption was spontaneous and endothermal. The high adsorption capacity indicates that the modified zeolite A is a suitable adsorption material for scale removal from aqueous solution. © 2014 American Institute of Chemical Engineers AIChE J, 61: 640–654, 2015
Analysis of solar‐driven gasification of biochar trickling through an interconnected porous structure
Authors: Kruesi Michael , Jovanovic Zoran R. , Haselbacher Andreas , Steinfeld Aldo
Published: November 2014

The efficient transfer of high‐temperature solar heat to the reaction site is crucial for the yield and selectivity of the solar‐driven gasification of biomass. The performance of a gas‐solid trickle‐bed reactor constructed from a high thermal conductivity porous ceramic packing has been investigated. Beech char particles were used as the model feedstock. A two‐dimensional finite‐volume model coupling chemical reaction with conduction, convection, and radiation of heat within the packing was developed and tested against measured temperatures and gasification rates. The sensitivity of the gasification rate and reactor temperatures to variations of the packing's pore diameter, porosity, thermal conductivity, and particle loading was numerically studied. A numerical comparison with a moving bed projected a more uniform temperature distribution and higher gasification rates due to the increased heat transfer via combined radiation and conduction through the trickle bed. © 2014 American Institute of Chemical Engineers AIChE J, 61: 867–879, 2015
Model for predicting the injury severity score
Authors: Hagiwara Shuichi , Oshima Kiyohiro , Murata Masato , Kaneko Minoru , Aoki Makoto , Kanbe Masahiko , Nakamura Takuro , Ohyama Yoshio , Tamura Jun'ichi
Published: November 2014

Aim

To determine the formula that predicts the injury severity score from parameters that are obtained in the emergency department at arrival.

Methods

We reviewed the medical records of trauma patients who were transferred to the emergency department of Gunma University Hospital between January 2010 and December 2010. The injury severity score, age, mean blood pressure, heart rate, Glasgow coma scale, hemoglobin, hematocrit, red blood cell count, platelet count, fibrinogen, international normalized ratio of prothrombin time, activated partial thromboplastin time, and fibrin degradation products, were examined in those patients on arrival. To determine the formula that predicts the injury severity score, multiple linear regression analysis was carried out. The injury severity score was set as the dependent variable, and the other parameters were set as candidate objective variables. IBM spss Statistics 20 was used for the statistical analysis. Statistical significance was set at P < 0.05. To select objective variables, the stepwise method was used.

Results

A total of 122 patients were included in this study. The formula for predicting the injury severity score (ISS) was as follows: ISS = 13.252–0.078(mean blood pressure) + 0.12(fibrin degradation products). The P‐value of this formula from analysis of variance was <0.001, and the multiple correlation coefficient (R) was 0.739 (R2 = 0.546). The multiple correlation coefficient adjusted for the degrees of freedom was 0.538. The Durbin–Watson ratio was 2.200.

Conclusions

A formula for predicting the injury severity score in trauma patients was developed with ordinary parameters such as fibrin degradation products and mean blood pressure. This formula is useful because we can predict the injury severity score easily in the emergency department.
Press‐through package mis‐swallowing: Usefulness of computed tomography
Authors: Kanazawa Ayako , Kamezaki Fumihiko , Kido Takashi , Yamasaki Seigen , Someya Kazuki , Takama Tatsuo , Otsubo Hiroki , Yoshikawa Ichiro , Kamochi Masayuki , Mayumi Toshihiko
Published: November 2014

Case

An 88‐year‐old female with Alzheimer's‐type dementia who mis‐swallowed a press‐through package visited our emergency department.

Outcome

Plain radiography detected no foreign bodies, whereas plain computed tomography showed an elliptical body with a high density in the lower esophagus. The press‐through package containing a tablet in the esophagogastric junction was successfully removed without severe complications using the endoscopic protector hood. In cases of press‐through package mis‐swallowing, it is important for emergency physicians to make an early and correct diagnosis of the location of the package, which shows high radiolucency. Based on the results of this case, we hypothesize that carrying out early computed tomography examinations is useful for identifying swallowed press‐through packages. Our retrospective investigation showed that computed tomography has a sensitivity of 100% for detecting press‐through packages.

Conclusion

We experienced a case of press‐through package mis‐swallowing diagnosed on computed tomography. We recommend performing computed tomography examinations, especially in patients with an uncertain history and unclear symptoms.
Amyotrophic lateral sclerosis onset is influenced by the burden of rare variants in known amyotrophic lateral sclerosis genes
Authors: Cady Janet , Allred Peggy , Bali Taha , Pestronk Alan , Goate Alison , Miller Timothy M. , Mitra Robi D. , Ravits John , Harms Matthew B. , Baloh Robert H.
Published: November 2014

Objective

To define the genetic landscape of amyotrophic lateral sclerosis (ALS) and assess the contribution of possible oligogenic inheritance, we aimed to comprehensively sequence 17 known ALS genes in 391 ALS patients from the United States.

Methods

Targeted pooled‐sample sequencing was used to identify variants in 17 ALS genes. Fragment size analysis was used to define ATXN2 and C9ORF72 expansion sizes. Genotype–phenotype correlations were made with individual variants and total burden of variants. Rare variant associations for risk of ALS were investigated at both the single variant and gene level.

Results

A total of 64.3% of familial and 27.8% of sporadic subjects carried potentially pathogenic novel or rare coding variants identified by sequencing or an expanded repeat in C9ORF72 or ATXN2; 3.8% of subjects had variants in >1 ALS gene, and these individuals had disease onset 10 years earlier (p = 0.0046) than subjects with variants in a single gene. The number of potentially pathogenic coding variants did not influence disease duration or site of onset.

Interpretation

Rare and potentially pathogenic variants in known ALS genes are present in >25% of apparently sporadic and 64% of familial patients, significantly higher than previous reports using less comprehensive sequencing approaches. A significant number of subjects carried variants in >1 gene, which influenced the age of symptom onset and supports oligogenic inheritance as relevant to disease pathogenesis. ANN NEUROL 2015;77:100–113
Mice with megalencephalic leukoencephalopathy with cysts: A developmental angle
Authors: Dubey Mohit , Bugiani Marianna , Ridder Margreet C. , Postma Nienke L. , Brouwers Eelke , Polder Emiel , Jacobs J. Gerbren , Baayen Johannes C. , Klooster Jan , Kamermans Maarten , Aardse Romy , de Kock Christiaan P. J. , Dekker Marien P. , van Weering Jan R. T. , Heine Vivi M. , Abbink Truus E. M. , Scheper Gert C. , Boor Ilja , Lodder Johannes C. , Mansvelder Huibert D. , van der Knaap Marjo S.
Published: November 2014

Objective

Megalencephalic leukoencephalopathy with cysts (MLC) is a genetic disease characterized by infantile onset white matter edema and delayed onset neurological deterioration. Loss of MLC1 function causes MLC. MLC1 is involved in ion–water homeostasis, but its exact role is unknown. We generatedMlc1‐null mice for further studies.

Methods

We investigated which brain cell types express MLC1, compared developmental expression in mice and men, and studied the consequences of loss of MLC1 inMlc1‐null mice.

Results

Like humans, mice expressed MLC1 only in astrocytes, especially those facing fluid–brain barriers. In mice, MLC1 expression increased until 3 weeks and then stabilized. In humans, MLC1 expression was highest in the first year, decreased, and stabilized from approximately 5 years.Mlc1‐null mice had early onset megalencephaly and increased brain water content. From 3 weeks, abnormal astrocytes were present with swollen processes abutting fluid–brain barriers. From 3 months, widespread white matter vacuolization with intramyelinic edema developed.Mlc1‐null astrocytes showed slowed regulatory volume decrease and reduced volume‐regulated anion currents, which increased upon MLC1 re‐expression.Mlc1‐null astrocytes showed reduced expression of adhesion molecule GlialCAM and chloride channel ClC‐2, but no substantial changes in other known MLC1‐interacting proteins.

Interpretation

Mlc1‐null mice replicate early stages of the human disease with early onset intramyelinic edema. The cellular functional defects, described for human MLC, were confirmed. The earliest change was astrocytic swelling, substantiating that in MLC the primary defect is in volume regulation by astrocytes. MLC1 expression affects expression of GlialCAM and ClC‐2. Abnormal interplay between these proteins is part of the pathomechanisms of MLC. ANN NEUROL 2015;77:114–131
Extended Reaction Scope of Thiamine Diphosphate Dependent Cyclohexane‐1,2‐dione Hydrolase: From CC Bond Cleavage to CC Bond Ligation
Authors: Loschonsky Sabrina , Wacker Tobias , Waltzer Simon , Giovannini Pier Paolo , McLeish Michael J. , Andrade Susana L. A. , Müller Michael
Published: November 2014

ThDP‐dependent cyclohexane‐1,2‐dione hydrolase (CDH) catalyzes the CC bond cleavage of cyclohexane‐1,2‐dione to 6‐oxohexanoate, and the asymmetric benzoin condensation between benzaldehyde and pyruvate. One of the two reactivities of CDH was selectively knocked down by mutation experiments. CDH‐H28A is much less able to catalyze the CC bond formation, while the ability for CC bond cleavage is still intact. The double variant CDH‐H28A/N484A shows the opposite behavior and catalyzes the addition of pyruvate to cyclohexane‐1,2‐dione, resulting in the formation of a tertiary alcohol. Several acyloins of tertiary alcohols are formed with 54–94 % enantiomeric excess. In addition to pyruvate, methyl pyruvate and butane‐2,3‐dione are alternative donor substrates for CC bond formation. Thus, the very rare aldehyde–ketone cross‐benzoin reaction has been solved by design of an enzyme variant.
An Isotope‐Coded Fluorogenic Cross‐Linker for High‐Performance Target Identification Based on Photoaffinity Labeling
Authors: Tomohiro Takenori , Morimoto Shota , Shima Toshiya , Chiba Junya , Hatanaka Yasumaru
Published: November 2014

A photoaffinity labeling (PAL)‐based method for the rapid identification of target proteins is presented in which a high‐performance chemical tag, an isotope‐coded fluorescent tag (IsoFT), can be attached to the interacting site by irradiation. Labeled peptides can be easily distinguished among numerous proteolytic digests by sequential detection with highly sensitive fluorescence spectroscopy and mass spectrometry. Subsequent MS/MS analysis provides amino acid sequence information with a higher depth of coverage. The combination of PAL and heterogeneous target‐selecting techniques significantly reduces the amount of time and protein required for identification. An additional photocleavable moiety successfully accelerated proteomic analysis using cell lysate. This method is a widely applicable approach for the rapid and accurate identification of interacting proteins.
Enantioselective Synthesis of α‐Secondary and α‐Tertiary Piperazin‐2‐ones and Piperazines by Catalytic Asymmetric Allylic Alkylation
Authors: Korch Katerina M. , Eidamshaus Christian , Behenna Douglas C. , Nam Sangkil , Horne David , Stoltz Brian M.
Published: November 2014

The asymmetric palladium‐catalyzed decarboxylative allylic alkylation of differentially N‐protected piperazin‐2‐ones allows the synthesis of a variety of highly enantioenriched tertiary piperazine‐2‐ones. Deprotection and reduction affords the corresponding tertiary piperazines, which can be employed for the synthesis of medicinally important analogues. The introduction of these chiral tertiary piperazines resulted in imatinib analogues which exhibited comparable antiproliferative activity to that of their corresponding imatinib counterparts.
Chiral Metal–Organic Frameworks Bearing Free Carboxylic Acids for Organocatalyst Encapsulation
Authors: Liu Yan , Xi Xiaobing , Ye Chengcheng , Gong Tengfei , Yang Zhiwei , Cui Yong
Published: November 2014

Two chiral carboxylic acid functionalized micro‐ and mesoporous metal–organic frameworks (MOFs) are constructed by the stepwise assembly of triple‐stranded heptametallic helicates with six carboxylic acid groups. The mesoporous MOF with permanent porosity functions as a host for encapsulation of an enantiopure organic amine catalyst by combining carboxylic acids and chiral amines in situ through acid–base interactions. The organocatalyst‐loaded framework is shown to be an efficient and recyclable heterogeneous catalyst for the asymmetric direct aldol reactions with significantly enhanced stereoselectivity in relative to the homogeneous organocatalyst.
Effect of a small amount of sulfur on the physical and mechanical properties of peroxide‐cured fully saturated HNBR compounds
Authors: Sheng Chunrui , Hu Zhiwei , Martin Hoch , Duan Yongxin , Zhang Jianming
Published: November 2014

Sulfur can be used as crosslink coagent in unsaturated elastomer. In this work, a fully saturated HNBR with 39 wt % nitrile content was selected to investigate the effect of a small amount of sulfur acting as crosslink coagent on the physical and mechanical properties of peroxide‐cured vulcanizates. First, selective cleavage of polysulfide (Sx) and monosulfide(S) bond by combined thiol‐piperidine treatment were performed and the existence of poly/monosulfide bond in sulfur‐contained HNBR compounds was verified. Then, no‐filler HNBR compounds with various content of sulfur were investigated to detect the influence of sulfur on the crosslink density and cure kinetics. The MDR results showed that the crosslink density of HNBR compounds reduced only when the amount of sulfur is 0.25 phr and above. Besides, the curing rate of no‐filler HNBR compounds increased with the increasing of the amount of sulfur and reached a maximum at a dosage of 0.25 phr sulfur. Finally, physical and mechanical properties of fully formulated compounds were evaluated and it was found that the addition of small amounts of sulfur in fully saturated HNBR compounds could improve the dynamic properties of peroxide‐cured HNBR compounds remarkably but at a cost of slightly higher compression set values and a small loss in heat aging resistance. In a conclusion, small amount of sulfur can impart the peroxide vulcanizates some “sulfide properties” like dynamic property, tensile strength, but at the same time, due to the introduction of sulfur, some “peroxide vulcanizates property” like heat‐resistance property, hot air resistance were weakened slightly. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41612.
Development of antibacterial silver treatments on HDPE nets for agriculture
Authors: De Simone Serena , Lombardi Fiorella Anna , Paladini Federica , Starace Giuseppe , Sannino Alessandro , Pollini Mauro
Published: November 2014

The defense mechanism of crops associated with the use of polymeric nets and fabrics is only physical and, hence, ineffective against the bacterial contaminations. The presence of an antibacterial agent associated with the use of conventional agro‐textiles can represent a great advantage in the prevention of plant diseases and for food safety. The aim of this work was the development of antibacterial silver‐coated HDPE nets for an innovative application such as agriculture. Antibacterial coatings on high‐density polyethylene nets were obtained by a patented nanosilver deposition technique based on the in situ photo‐reduction of a silver solution. The concentration of silver deposited was defined by testing different silver solutions from a biological point of view. Moreover, in order to improve the adhesion of the silver coating to the substrate, the nets underwent low‐pressure plasma treatment before the silver deposition. The materials were characterized in terms of quality of the coating through scanning electron microscopy, and in terms of antibacterial capability on Gram positive and Gram negative bacteria through qualitative and quantitative microbiological tests. The most effective process parameters were defined and the importance of performing plasma pretreatment on this specific substrate was assessed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41623.
Modifying biodegradable plastics with additives based on condensed tannin esters
Authors: Grigsby Warren J. , Bridson James H. , Schrade Carmen
Published: November 2014

Condensed tannins derived from Pinus radiata bark have been esterified and added to biodegradable plastics as extrusion compounded functional plastic additives. The presence of longer alkyl chain hexanoate esters promoted tannin miscibility in the commercial polyesters Bionolle™ and Biopol™ whereas short chain acetate esters tended to remain as discrete domains, acting as fillers in the processed plastics. In the aliphatic polyester Bionolle the presence of tannin esters at typical plastic additive loadings did not alter plastic mechanical properties whereas at 5% content in Biopol the tannin‐additives reduced both flexural and tensile properties. Similarly tannin esters do not alter the melt or glass transition temperatures of the polyesters, but tannin hexanoate at 5% can influence the crystallization temperatures. Artificially aging plastics realized the functionality these plant extracts can impart to plastics in acting to reduce ultraviolet (UV)‐induced plastic degradation. Results indicate the tannin‐additives likely provide a stabilising role through inhibiting UV penetration into the plastic, with color analysis suggesting the tannin moiety itself was sacrificial and preferentially degrading. The imparted UV stability was linked to the dissolution of tannin esters in the plastic with longer chain esters providing greater protection against UV degradation. Tannin esters showed potential as functional additives for biodegradable polymers enhancing the UV stability of the plastic. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41626.
Synthesis and Antiaromatic Properties of Highly Planar Dithiaamethyrin
Authors: Ishimaru Yoshihiro , Shimoyama Naoyuki , Fujihara Takashi , Watanabe Keigo , Setsune Jun‐ichiro
Published: November 2014

2,5‐Bis(4‐propyl‐2‐pyrrolyl)thiophene was reacted with aryl aldehydes to afford large porphyrinoids; [24]dithiaamethyrin(1.0.0.1.0.0) and [36]trithianonaphyrin(1.0.0.1.0.0.1.0.0). X‐ray crystallography of the dithiaamethyrin revealed a highly planar ring structure with mean plane deviation (MPD) value of 0.053 Å. A large positive NICS(0) value (+13.9 ppm) calculated for this planar 24π system unambiguously indicates an antiaromatic character that is consistent with a remarkably low field 1H chemical shift of the inner NH proton at 24.0 ppm. The magnitude of the paratropic ring current effect in the 24π amethyrin framework in the free base form and the diprotonated form was discussed on the basis of the MPD value and the NICS value. The present dithiaamethyrin is much more strongly antiaromatic than the dodecaalkylamethyrin in their free base forms, but the order inversed in their diprotonated forms.
Dynamic Slicing of Petri Nets Based on Structural Dependency Graph and its Application in System Analysis
Authors: Yu Wangyang , Ding Zhijun , Fang Xianwen
Published: November 2014

Petri net models are frequently complex and difficult to understand and modify. Slicing technology is very useful in analyzing programs, and has been widely used in specification level for model reduction. So it is necessary to explore slicing methods for Petri nets. This paper proposes a dynamic slicing technique for Petri nets based on the structural dependency graph (SDG). Firstly, the SDG is constructed from the slicing criterion by a backtracking algorithm. Secondly, based on the SDG and a given marking, the dynamic slice can be acquired. As a case study, the proposed method is applied to a control system, and a simulation tool is developed for validating this method and automatically generating the slice. The algorithms can be useful in automatically identifying the parts of the model that affect a state of interest, and provide the basic technical support for alleviating the difficulty of formal verification and analysis.
Longitudinal Volumetric Brain Changes in Autism Spectrum Disorder Ages 6–35 Years
Authors: Lange Nicholas , Travers Brittany G. , Bigler Erin D. , Prigge Molly B.D. , Froehlich Alyson L. , Nielsen Jared A. , Cariello Annahir N. , Zielinski Brandon A. , Anderson Jeffrey S. , Fletcher P. Thomas , Alexander Andrew A. , Lainhart Janet E.
Published: November 2014

Since the impairments associated with autism spectrum disorder (ASD) tend to persist or worsen from childhood into adulthood, it is of critical importance to examine how the brain develops over this growth epoch. We report initial findings on whole and regional longitudinal brain development in 100 male participants with ASD (226 high‐quality magnetic resonance imaging [MRI] scans; mean inter‐scan interval 2.7 years) compared to 56 typically developing controls (TDCs) (117 high‐quality scans; mean inter‐scan interval 2.6 years) from childhood into adulthood, for a total of 156 participants scanned over an 8‐year period. This initial analysis includes between one and three high‐quality scans per participant that have been processed and segmented to date, with 21% having one scan, 27% with two scans, and 52% with three scans in the ASD sample; corresponding percentages for the TDC sample are 30%, 30%, and 40%. The proportion of participants with multiple scans (79% of ASDs and 68% of TDCs) was high in comparison to that of large longitudinal neuroimaging studies of typical development. We provide volumetric growth curves for the entire brain, total gray matter (GM), frontal GM, temporal GM, parietal GM, occipital GM, total cortical white matter (WM), corpus callosum, caudate, thalamus, total cerebellum, and total ventricles. Mean volume of cortical WM was reduced significantly. Mean ventricular volume was increased in the ASD sample relative to the TDCs across the broad age range studied. Decreases in regional mean volumes in the ASD sample most often were due to decreases during late adolescence and adulthood. The growth curve of whole brain volume over time showed increased volumes in young children with autism, and subsequently decreased during adolescence to meet the TDC curve between 10 and 15 years of age. The volume of many structures continued to decline atypically into adulthood in the ASD sample. The data suggest that ASD is a dynamic disorder with complex changes in whole and regional brain volumes that change over time from childhood into adulthood. Autism Res 2015, 8: 82–93. © 2014 International Society for Autism Research, Wiley Periodicals, Inc.