bluuebunny/crossref_metadata_2025 huggingface dataset:
Academic 15: Evaluating library and IT staff responses to disruption and change in higher education
Authors: Stephens Michael , Wedaman David , Freeman Ellen , Hicks Alison , Matthews-DeNatale Gail , Wahl Diane , Spiro Lisa
Published: June 2014

Academic 15 (A15), an interview–based research project, explores the perceptions of university library and information technology (IT) staff related to the challenges impacting higher education as a result of technological advances. Faced with disruption on many fronts, academic library and IT staff have adapted and adopted a number of tools and processes to cope with accelerating change. This includes seeking out collaborative partnerships, working within financial constraints, discovering alternate funding sources, and experimenting with new roles in the evolving model of higher education. This paper presents findings to guide the future design and implementation of resilient support systems for library, educational technology, and IT staff.
Hidden participation in the public sphere: Understanding Malaysian university students’ public discourse practices in cyberspace
Authors: Chan Mei-Yuit , Rafik-Galea Shameem , Yap Ngee-Thai
Published: June 2014

A recent development in Malaysia was the unprecedented rise in young Malaysians’ participation in the country’s social and political affairs, facilitated almost entirely by the Internet. This phenomenon caught many by surprise considering that university students in the country had been barred through legislation from active involvement in political activities for more than 30 years. Through a survey of 514 university students in a Malaysian public university, supplemented by interview data and samples of students’ writing, this study investigated in which ways Malaysian tertiary students are participating in the public sphere through the Internet. Following Hauser’s (1999) conception of public discourse as personal, interactive, informal, and distributed voices among the citizenry, we argue for a perspective that explains how online interactions in the friendship frame among young people represent their participation in the public sphere in the context of contemporary society.
Congressmen in the age of social network sites: Brazilian representatives and Twitter use
Authors: Marques Francisco Paulo Jamil Almeida , Aquino Jakson Alves de , Miola Edna
Published: June 2014

This paper investigates the factors that influence how members of the Brazilian House of Representatives adopt Twitter as part of their political communication strategy. Our intention is to understand the main variables that lead legislators to invest time and resources in microblogging. This quantitative study examined all of the 457 official congressional accounts registered on Twitter. These accounts were monitored weekly between February 2012 and February 2013. After empirically exploring the data, this work reflects on the results thanks in part to an examination of the literature on the intersection of the Internet and politics. The results indicate correlations between the use of Twitter and attributes like age and occupation of leadership positions.
Revisiting an Early Thule Inuit occupation of Skraeling Island, Canadian High Arctic
Authors: Howse Lesley
Published: June 2014

This paper presents the faunal material excavated from an Early Thule Inuit semi-subterranean house, house 15, from the Skraeling Island site (SfFk-4). In an effort to understand how the occupants of the house interacted with animals, a fine-grained zooarchaeological analysis is employed. Patterning in taxonomic and bone modification frequencies, skeletal element distributions, and prey demography are discussed. Inuit oral histories, mythology, and ethnographic sources are used to help interpret the results of the analysis and reconstruct the group’s subsistence economy.
A 2000 year natural record of magnitudes and frequencies for the largest Upper Colorado River floods near Moab, Utah
Authors: Greenbaum Noam , Harden Tessa M. , Baker Victor R. , Weisheit John , Cline Michael L. , Porat Naomi , Halevi Rafi , Dohrenwend John
Published: June 2014

Using well‐established procedures for paleoflood hydrology and employing optically stimulated luminescence (OSL) geochronology, we analyzed a very well‐preserved natural record of 44 Upper Colorado River extreme floods with discharges ranging from 1800 to 9200 m3s−1. These are the largest floods occurring during the last 2140 ± 220 years, and this natural record indicates that large floods are much more frequent than can be estimated by extrapolation from the stream gaging record that extends back to 1914. Most of these large floods occurred during the last 500 years, and the two largest floods in the record both exceeded the probable maximum flood (PMF) estimated at 8500 m3s−1(300,000 cfs) for nearby Moab, Utah. Another four floods, with discharges greater than 7000 m3s−1, occurred during the last two millennia. Flood frequency analyses using the FLDFRQ3 model yields the following values, depending on the Manningnroughness coefficients: 100 yr flood—4670–4990 m3s−1; 500 yr flood—6675–7270 m3s−1; 1000 yr flood—7680–8440 m3s−1. The presumed PMF discharge (8500 m3s−1) gets assigned a recurrence interval of about 1000 years, and the largest historical 1884 flood (3540 m3s−1)—a recurrence interval of <100 years. Flood frequency analysis for the Moab Valley based on the gaged record (1914–2012) yield 2730 m3s−1for the 100 yr flood and 3185 m3s−1for the 500 yr flood. This underestimation of the frequency of large floods from the gage data results from effects on that record by modern regulation of upstream river flow and associated water extraction for agriculture.
Extent of the rain‐snow transition zone in the western U.S. under historic and projected climate
Authors: Klos P. Zion , Link Timothy E. , Abatzoglou John T.
Published: June 2014

This study investigates the extent of the rain‐snow transition zone across the complex terrain of the western United States for both late 20th century climate and projected changes in climate by the mid‐21st century. Observed and projected temperature and precipitation data at 4 km resolution were used with an empirical probabilistic precipitation phase model to estimate and map the likelihood of snow versus rain occurrence. This approach identifies areas most likely to undergo precipitation phase change over the next half century. At broad scales, these projections indicate an average 30% decrease in areal extent of winter wet‐day temperatures conducive to snowfall over the western United States. At higher resolution scales, this approach identifies existing and potential experimental sites best suited for research investigating the mechanisms linking precipitation phase change to a broad array of processes, such as shifts in rain‐on‐snow flood risk, timing of water resource availability, and ecosystem dynamics.
Solar wind‐driven thermospheric winds over the Venus North Polar region
Authors: Lundin R. , Barabash S. , Futaana Y. , Holmström M. , Sauvaud J.‐A. , Fedorov A.
Published: June 2014

Data from the neutral particle imager (NPI) on Venus Express reveals the presence of a persistent +Y (Venus Solar‐Oriented) flow of Energetic Neutral Atoms (ENAs) in the Venus polar thermosphere. The overall flow morphology and altitude distribution of ENAs, solar wind H+ (SWH+), and ionospheric O+ imply that SWH+&O+ Charge Exchange (CE) with thermosphere neutrals causes the ENA flow. A dusk‐dawn and noon‐midnight ENA flux asymmetry is consistent with an asymmetric CE‐interaction with higher ENA fluxes in the dayside and dawn (+Y). Model ENA fluxes derived from CE between SWH+&O+ and a model oxygen thermosphere is consistent with NPI data. Adding energy‐corrected NPI fluxes and ion fluxes gives essentially constant fluxes of ≈1012 part/(m2s) in the altitude range of 200–1200 km. The energy and momentum of the 1–10 km/s ion and ENA flow, induced by solar wind forcing, should have implications for wind patterns in the polar thermosphere above 200 km.
Comment on “Temporal and spatial precursors in ionospheric total electron content of the 16 October 1999 Mw 7.1 Hector Mine earthquake” by Su et al. (2013)
Authors: Masci F. , Thomas J. N.
Published: June 2014

We review the recent paper by Su et al. (2013). Using Global Position System and Global Ionospheric Maps data, Su et al. claimed to have found ionospheric precursors a few days before the 16 October 1999 Hector Mine, California, earthquake. They proposed that this type of analysis of ionospheric data may be useful for locating forthcoming large earthquakes. In this Comment, we reexamine these data and show that ionospheric anomalies reported by Su et al. were not precursors to the Hector Mine earthquake. Therefore, their proposed analysis is not useful in the context of earthquake prediction.
Global morphology and spectral properties of EMIC waves derived from CRRES observations
Authors: Meredith Nigel P. , Horne Richard B. , Kersten Tobias , Fraser Brian J. , Grew Russell S.
Published: June 2014

Gyroresonant wave‐particle interactions with electromagnetic ion cyclotron (EMIC) waves are a potentially important loss process for relativistic electrons in the Earth's radiation belts. Here we perform a statistical analysis of the EMIC waves observed by the Combined Release and Radiation Effects Satellite (CRRES) to determine the global morphology and spectral properties of the waves and to help assess their role in radiation belt dynamics. Helium band EMIC waves, with intensities, , greater than 0.1 nT2, are most prevalent during active conditions (AE> 300 nT), from 4 <L*< 7 in the afternoon sector, with an average percentage occurrence of 2.7%. Hydrogen band EMIC wave events, with intensities greater than 0.1 nT2, are also most prevalent in the afternoon sector during active conditions in the same region, but they are less frequent with an average percentage occurrence of 0.6%. The average intensity of the helium and hydrogen band EMIC waves in the region 4 <L*< 7 in the afternoon sector during active conditions is 2 nT2 and 0.5 nT2, respectively, and suggests that the waves can cause strong diffusion. However, the time‐averaged properties are very different, being a factor of 30–50 lower for helium and hydrogen band EMIC waves, respectively, suggesting that the overall effect will be correspondingly weaker. Nevertheless, the moderate and strong EMIC wave events with reported on here will contribute to relativistic electron loss in the Earth's radiation belts and should be included in radiation belt models.
Efficiency Enhancement of Organic Light‐Emitting Diodes Incorporating a Highly Oriented Thermally Activated Delayed Fluorescence Emitter
Authors: Mayr Christian , Lee Sae Youn , Schmidt Tobias D. , Yasuda Takuma , Adachi Chihaya , Brütting Wolfgang
Published: June 2014

An organic light‐emitting diode (OLED) with the blue emitter CC2TA showing thermally activated delayed fluorescence (TADF) is presented exhibiting an external quantum efficiency () of 11% ± 1%, which clearly exceeds the classical limit for fluorescent OLEDs. The analysis of the emission layer by angular dependent photoluminescence (PL) measurements shows a very high degree of 92% horizontally oriented transition dipole moments. Excited states lifetime measurements of the prompt fluorescent component under PL excitation yield a radiative quantum efficiency of 55% of the emitting species. Thus, the radiative exciton fraction has to be significantly higher than 25% due to TADF. Performing a simulation based efficiency analysis for the OLED under investigation allows for a quantification of individual contributions to the efficiency increase originating from horizontal emitter orientation and TADF. Remarkably, the strong horizontal emitter orientation leads to a light‐outcoupling efficiency of more than 30%.
Hypomyelinating leukodystrophies: Translational research progress and prospects
Authors: Pouwels Petra J. W. , Vanderver Adeline , Bernard Genevieve , Wolf Nicole I. , Dreha‐Kulczewksi Steffi F. , Deoni Sean C. L. , Bertini Enrico , Kohlschütter Alfried , Richardson William , ffrench‐Constant Charles , Köhler Wolfgang , Rowitch David , Barkovich A. James
Published: June 2014

Hypomyelinating leukodystrophies represent a genetically heterogeneous but clinically overlapping group of heritable disorders. Current management approaches in the care of the patient with a hypomyelinating leukodystrophy include use of serial magnetic resonance imaging (MRI) to establish and monitor hypomyelination, molecular diagnostics to determine a specific etiology, and equally importantly, careful attention to neurologic complications over time. Emerging research in oligodendrocyte biology and neuroradiology with bedside applications may result in the possibility of clinical trials in the near term, yet there are significant gaps in knowledge in disease classification, characterization, and outcome measures in this group of disorders. Here we review the biological background of myelination, the clinical and genetic variability in hypomyelinating leukodystrophies, and the insights that can be obtained from current MRI techniques. In addition, we discuss ongoing research approaches to define potential outcome markers for future clinical trials. Ann Neurol 2014;76:5–19
Acute mechanisms underlying antibody effects in anti–N‐methyl‐D‐aspartate receptor encephalitis
Authors: Moscato Emilia H. , Peng Xiaoyu , Jain Ankit , Parsons Thomas D. , Dalmau Josep , Balice‐Gordon Rita J.
Published: June 2014

Objective

A severe but treatable form of immune‐mediated encephalitis is associated with antibodies in serum and cerebrospinal fluid (CSF) against the GluN1 subunit of the N‐methyl‐D‐aspartate receptor (NMDAR). Prolonged exposure of hippocampal neurons to antibodies from patients with anti‐NMDAR encephalitis caused a reversible decrease in the synaptic localization and function of NMDARs. However, acute effects of the antibodies, fate of the internalized receptors, type of neurons affected, and whether neurons develop compensatory homeostatic mechanisms were unknown and are the focus of this study.

Methods

Dissociated hippocampal neuron cultures and rodent brain sections were used for immunocytochemical, physiological, and molecular studies.

Results

Patient antibodies bind to NMDARs throughout the rodent brain, and decrease NMDAR cluster density in both excitatory and inhibitory hippocampal neurons. They rapidly increase the internalization rate of surface NMDAR clusters, independent of receptor activity. This internalization likely accounts for the observed decrease in NMDAR‐mediated currents, as no evidence of direct blockade was detected. Once internalized, antibody‐bound NMDARs traffic through both recycling endosomes and lysosomes, similar to pharmacologically induced NMDAR endocytosis. The antibodies are responsible for receptor internalization, as their depletion from CSF abrogates these effects in hippocampal neurons. We find that although anti‐NMDAR antibodies do not induce compensatory changes in glutamate receptor gene expression, they cause a decrease in inhibitory synapse density onto excitatory hippocampal neurons.

Interpretation

Our data support an antibody‐mediated mechanism of disease pathogenesis driven by immunoglobulin‐induced receptor internalization. Antibody‐mediated downregulation of surface NMDARs engages homeostatic synaptic plasticity mechanisms, which may inadvertently contribute to disease progression. Ann Neurol 2014;76:108–119
Peptid‐Nanoröhren
Authors: Hamley Ian W.
Published: June 2014

In diesem Aufsatz wird die Selbstorganisation verschiedener Klassen von Peptiden, einschließlich cyclischer Peptide, Amyloidpeptide und tensidartiger Peptide, zu Nanoröhrenstrukturen besprochen. Außer den Modi der Selbstorganisation werden auch Anwendungen auf den Gebieten der Bionanotechnologie und der synthetischen Materialien diskutiert.
Organokatalytische asymmetrische Epoxidierungen – Reaktionen, Mechanismen und Anwendungen
Authors: Davis Rebecca L. , Stiller Julian , Naicker Tricia , Jiang Hao , Jørgensen Karl Anker
Published: June 2014

Chirale Epoxide sind vielseitige Bausteine in der Synthese komplexer organischer Gerüste. Durch die hohe Spannung ihres dreigliedrigen Rings können Epoxide eine Reihe von nucleophilen Ringöffnungsreaktionen eingehen. Nach der Entwicklung der Sharpless‐Epoxidierung folgten zahlreiche wichtige Fortschritte, und das rasch aufstrebende Feld der asymmetrischen Organokatalyse stellt nun Katalysatoren für die Epoxidierung eines breiten Spektrums an ungesättigten Carbonylverbindungen bereit. In diesem Kurzaufsatz sind jüngste Entwicklungen auf dem Gebiet organokatalytischer asymmetrischer Epoxidierungen zusammengefasst. Die vorgeschlagenen Reaktionsmechanismen werden beschrieben, und Anwendungen werden beschrieben.
Auf dem Weg zu größtmöglicher Effizienz bei der katalytischen Nutzung von Edelmetallen: atomar dispergiertes Oberflächen‐Platin
Authors: Bruix Albert , Lykhach Yaroslava , Matolínová Iva , Neitzel Armin , Skála Tomáš , Tsud Nataliya , Vorokhta Mykhailo , Stetsovych Vitalii , Ševčíková Klára , Mysliveček Josef , Fiala Roman , Václavů Michal , Prince Kevin C. , Bruyère Stéphanie , Potin Valérie , Illas Francesc , Matolín Vladimír , Libuda Jörg , Neyman Konstantin M.
Published: June 2014

Platin ist das am vielseitigsten eingesetzte Element in der Katalyse. Allerdings begrenzt der hohe Preis des Edelmetalls die Verwendung in vielen Bereichen, z. B. in Katalysatormaterialien für Brennstoffzellen. Trotzdem nutzen konventionelle Katalysatoren oftmals nur einen Bruchteil ihres Pt‐Gehaltes, nämlich diejenigen Atome, die sich auf der Oberfläche des Katalysators befinden. Eine effizientere Edelmetallnutzung setzt somit eine höhere, bevorzugt atomare Dispersion der Pt‐Atome auf der Oberfläche voraus. Tatsächlich ist es möglich, solche atomar dispergierten Pt‐Spezies mit sehr hoher Stabilität auf einer Katalysatoroberfläche herzustellen. Mithilfe von DFT‐Rechnungen identifizieren wir ein spezifisches Strukturmerkmal solcher Systeme, eine sogenannte Cerdioxid‐“Nanotasche”, die Pt2+‐Ionen so stabilisiert, dass diese sowohl thermischem Sintern als auch einer Diffusion in tiefere Katalysatorebenen widerstehen. Die theoretisch vorhergesagte außerordentliche Stabilität wurde experimentell an Modellkatalysatoren verifiziert. In realen Pt‐CeO2‐Nanomaterialien, die tatsächlich eine sehr hohe katalytische Aktivität in Brennstoffzellen zeigen, identifizieren wir diese Bindungsstellen ebenfalls. Die so erhaltenen neuen Materialien können dazu beitragen, den Bedarf an Edelmetallen für Katalysatormaterialien erheblich zu reduzieren.
Picket‐Fence Polythiophene and its Diblock Copolymers that Afford Microphase Separations Comprising a Stacked and an Isolated Polythiophene Ensemble
Authors: Pan Chengjun , Sugiyasu Kazunori , Aimi Junko , Sato Akira , Takeuchi Masayuki
Published: June 2014

All‐polythiophene diblock copolymers, comprising one unsheathed block and one fenced block, were synthesized through catalyst‐transfer polycondensation. The unsheathed block self‐assembles through π‐π stacking, thereby inducing microphase separation. Consequently, we have succeeded in creating a microphase separation comprising an ensemble of stacked and isolated polythiophenes. This achievement could be extended to various unexplored applications as a result of the integration of the contrasting functions of the two blocks.
Fast Prediction of Adsorption Properties for Platinum Nanocatalysts with Generalized Coordination Numbers
Authors: Calle‐Vallejo Federico , Martínez José I. , García‐Lastra Juan M. , Sautet Philippe , Loffreda David
Published: June 2014

Platinum is a prominent catalyst for a multiplicity of reactions because of its high activity and stability. As Pt nanoparticles are normally used to maximize catalyst utilization and to minimize catalyst loading, it is important to rationalize and predict catalytic activity trends in nanoparticles in simple terms, while being able to compare these trends with those of extended surfaces. The trends in the adsorption energies of small oxygen‐ and hydrogen‐containing adsorbates on Pt nanoparticles of various sizes and on extended surfaces were analyzed through DFT calculations by making use of the generalized coordination numbers of the surface sites. This simple and predictive descriptor links the geometric arrangement of a surface to its adsorption properties. It generates linear adsorption‐energy trends, captures finite‐size effects, and provides more accurate descriptions than d‐band centers and usual coordination numbers. Unlike electronic‐structure descriptors, which require knowledge of the densities of states, it is calculated manually. Finally, it was shown that an approximate equivalence exists between generalized coordination numbers and d‐band centers.
Catalytic Biorefining of Plant Biomass to Non‐Pyrolytic Lignin Bio‐Oil and Carbohydrates through Hydrogen Transfer Reactions
Authors: Ferrini Paola , Rinaldi Roberto
Published: June 2014

Through catalytic hydrogen transfer reactions, a new biorefining method results in the isolation of depolymerized lignin—a non‐pyrolytic lignin bio‐oil—in addition to pulps that are amenable to enzymatic hydrolysis. Compared with organosolv lignin, the lignin bio‐oil is highly susceptible to further hydrodeoxygenation under low‐severity conditions and therefore establishes a unique platform for lignin valorization by heterogeneous catalysis. Overall, the potential of a catalytic biorefining method designed from the perspective of lignin utilization is reported.
Cold Denaturation of α‐Synuclein Amyloid Fibrils
Authors: Ikenoue Tatsuya , Lee Young‐Ho , Kardos József , Saiki Miyu , Yagi Hisashi , Kawata Yasushi , Goto Yuji
Published: June 2014

Although amyloid fibrils are associated with numerous pathologies, their conformational stability remains largely unclear. Herein, we probe the thermal stability of various amyloid fibrils. α‐Synuclein fibrils cold‐denatured to monomers at 0–20 °C and heat‐denatured at 60–110 °C. Meanwhile, the fibrils of β2‐microglobulin, Alzheimer’s Aβ1‐40/Aβ1‐42 peptides, and insulin exhibited only heat denaturation, although they showed a decrease in stability at low temperature. A comparison of structural parameters with positive enthalpy and heat capacity changes which showed opposite signs to protein folding suggested that the burial of charged residues in fibril cores contributed to the cold denaturation of α‐synuclein fibrils. We propose that although cold‐denaturation is common to both native proteins and misfolded fibrillar states, the main‐chain dominated amyloid structures may explain amyloid‐specific cold denaturation arising from the unfavorable burial of charged side‐chains in fibril cores.
Asymmetric Organocatalytic Epoxidations: Reactions, Scope, Mechanisms, and Applications
Authors: Davis Rebecca L. , Stiller Julian , Naicker Tricia , Jiang Hao , Jørgensen Karl Anker
Published: June 2014

Chiral epoxides serve as versatile building blocks in the synthesis of complex organic frameworks. The high strain imposed by the three‐membered ring system makes epoxides prone to a variety of nucleophilic ring‐opening reactions. Since the development of the Sharpless epoxidation, there have been many important contributions and advances in this area. With the rapid development of the field of asymmetric organocatalysis, a wide range of organocatalysts is now able to catalyze the epoxidation of broad class of unsaturated carbonyl compounds. In this Minireview, recent progress in the development of organocatalytic asymmetric epoxidation methods, the proposed mechanisms of these reactions and their applications as intermediates is reported.
Catalytic Zinc Complexes for Phosphate Diester Hydrolysis
Authors: Tirel Emmanuel Y. , Bellamy Zoë , Adams Harry , Lebrun Vincent , Duarte Fernanda , Williams Nicholas H.
Published: June 2014

Creating efficient artificial catalysts that can compete with biocatalysis has been an enduring challenge which has yet to be met. Reported herein is the synthesis and characterization of a series of zinc complexes designed to catalyze the hydrolysis of phosphate diesters. By introducing a hydrated aldehyde into the ligand we achieve turnover for DNA‐like substrates which, combined with ligand methylation, increases reactivity by two orders of magnitude. In contrast to current orthodoxy and mechanistic explanations, we propose a mechanism where the nucleophile is not coordinated to the metal ion, but involves a tautomer with a more effective Lewis acid and more reactive nucleophile. This data suggests a new strategy for creating more efficient metal ion based catalysts, and highlights a possible mode of action for metalloenzymes.
Maximum Noble‐Metal Efficiency in Catalytic Materials: Atomically Dispersed Surface Platinum
Authors: Bruix Albert , Lykhach Yaroslava , Matolínová Iva , Neitzel Armin , Skála Tomáš , Tsud Nataliya , Vorokhta Mykhailo , Stetsovych Vitalii , Ševčíková Klára , Mysliveček Josef , Fiala Roman , Václavů Michal , Prince Kevin C. , Bruyère Stéphanie , Potin Valérie , Illas Francesc , Matolín Vladimír , Libuda Jörg , Neyman Konstantin M.
Published: June 2014

Platinum is the most versatile element in catalysis, but it is rare and its high price limits large‐scale applications, for example in fuel‐cell technology. Still, conventional catalysts use only a small fraction of the Pt content, that is, those atoms located at the catalyst’s surface. To maximize the noble‐metal efficiency, the precious metal should be atomically dispersed and exclusively located within the outermost surface layer of the material. Such atomically dispersed Pt surface species can indeed be prepared with exceptionally high stability. Using DFT calculations we identify a specific structural element, a ceria “nanopocket”, which binds Pt2+ so strongly that it withstands sintering and bulk diffusion. On model catalysts we experimentally confirm the theoretically predicted stability, and on real Pt‐CeO2 nanocomposites showing high Pt efficiency in fuel‐cell catalysis we also identify these anchoring sites.
Irreversible Inhibitors of the Epidermal Growth Factor Receptor: Thienopyrimidine Core with α,β‐Unsaturated Amide Side Chain
Authors: Yang Xiu L. , Wang Tian C. , Lin Sen , Fan Hou X.
Published: June 2014

Overexpression of epidermal growth factor receptor (EGFR) tyrosine kinases has been found in a variety of cancers such as breast, ovarian, colon, and non‐small‐cell lung cancers, which is associated with poor prognosis in patients. In an effort to find effective irreversible inhibitors of the EGFR tyrosine kinase family (mainly HER2), two series of HER2 tyrosine kinase inhibitors with thieno[3,2‐d]pyridine and thieno[2,3‐d]pyridine as central part and with a basic α,β‐unsaturated amide side chain were developed. The α,β‐unsaturated amide side chain (the Michael acceptor) at the 6‐position, which forms a covalent bond to Cys773 located in the ATP binding pocket of the EGFR enzyme, is a major factor in the generation of irreversible inhibition. In our study, thienopyrimidine instead of quinazoline was used as the central structure, and different substituents were introduced at the 4‐position to investigate the structure–activity relationships. The thieno[2,3‐d]pyrimidine derivatives 16a–d showed potent HER2 enzyme inhibition and anti‐proliferative activity against SK‐BR‐3 cells. Especially, (E)‐N‐(4‐((3‐chloro‐4‐(pyridin‐2‐ylmethoxy)phenyl)amino)thieno[2,3‐d]pyrimidin‐6‐yl)‐4‐(dimethylamino)but‐2‐enamide 16d was identified as a potential irreversible HER2 inhibitor. Both its catalytic enzyme activity profile and its cellular efficacy were found to be superior to those of the marketed drug lapatinib.
Eye‐tracking analysis of user behavior and performance in web search on large and small screens
Authors: Kim Jaewon , Thomas Paul , Sankaranarayana Ramesh , Gedeon Tom , Yoon Hwan‐Jin
Published: June 2014

In recent years, searching the web on mobile devices has become enormously popular. Because mobile devices have relatively small screens and show fewer search results, search behavior with mobile devices may be different from that with desktops or laptops. Therefore, examining these differences may suggest better, more efficient designs for mobile search engines. In this experiment, we use eye tracking to explore user behavior and performance. We analyze web searches with 2 task types on 2 differently sized screens: one for a desktop and the other for a mobile device. In addition, we examine the relationships between search performance and several search behaviors to allow further investigation of the differences engendered by the screens. We found that users have more difficulty extracting information from search results pages on the smaller screens, although they exhibit less eye movement as a result of an infrequent use of the scroll function. However, in terms of search performance, our findings suggest that there is no significant difference between the 2 screens in time spent on search results pages and the accuracy of finding answers. This suggests several possible ideas for the presentation design of search results pages on small devices.
Testing the strength of the normative approach in citation theory through relational bibliometrics: The case of italian sociology
Authors: Riviera Emanuela
Published: June 2014

In scientometrics, citer behavior is traditionally investigated using one of two main approaches. According to the normative point of view, the behavior of scientists is regulated by norms that make the detection of citation patterns useful for the interpretation of bibliometric measures. According to the constructivist perspective, citer behavior is influenced by other factors linked to the social and/or psychological sphere that do not allow any statistical inferences that are useful for the purposes of interpretation. An intermediate position supports normative theories in describing citer behavior with respect to high citation frequencies and constructivist theories with respect to low citation counts. In this paper, this idea was tested in a case study of the Italian sociology community. Italian sociology is characterized by an unusual organization into three “political” or “ideological” camps, and belonging to one camp can be considered a potentially strong constructivist reason to cite. An all‐author co‐citation analysis was performed to map the structure of the Italian sociology community and look for evidence of three camps. We did not expect to find evidence of this configuration in the co‐citation map. The map, in fact, included authors who obtained high citation counts that are supposedly produced by a normative‐oriented behavior. The results confirmed this hypothesis and showed that the clusters seemed to be divided according to topic and not by camp. Relevant scientific works were cited by the members of the entire community regardless of their membership in any particular camp.
Palladium‐Catalyzed Direct C2 Arylation of N‐Substituted Indoles with 1‐Aryltriazenes
Authors: Liu Can , Miao Tao , Zhang Lei , Li Pinhua , Zhang Yicheng , Wang Lei
Published: June 2014

A novel and efficient palladium‐catalyzed C2 arylation of N‐substituted indoles with 1‐aryltriazenes for the synthesis of 2‐arylindoles was developed. In the presence of BF3⋅OEt2 and palladium(II) acetate (Pd(OAc)2), N‐substituted indoles reacted with 1‐aryltriazenes in N,N‐dimethylacetamide (DMAC) to afford the corresponding aryl–indole‐type products in good to excellent yields.
Unprecedented Cobalt‐Catalyzed Isomerization Reactions to Single Skipped 2,4,7‐Trienes Applied in the Synthesis of Urushiol
Authors: Schmidt Anastasia , Hilt Gerhard
Published: June 2014

The cobalt‐catalyzed isomerization of 1,3‐dienes to 2Z,4E‐dienes was realized for the very challenging substrates with an additional double bond in the side chain. An isomerization to the conjugated 3,5,7‐triene derivative was not observed, which is in stark contrast to observations with many other isomerization catalysts. Accordingly, the synthesis of the natural product urushiol, which has a sensitive 2Z,4E,7Z‐triene subunit in the side chain, was investigated. The O‐protected urushiol derivative was generated selectively without isomerization to the conjugated 3,5,7‐triene or Z/E‐isomerization of the double bond at position 7.
Interaction between the SLC19A1 gene and maternal first trimester fever on offspring neural tube defects
Authors: Pei Lijun , Zhu Huiping , Ye Rongwei , Wu Jilei , Liu Jianmeng , Ren Aiguo , Li Zhiwen , Zheng Xiaoying
Published: June 2014

Background

Many studies have indicated that the reduced folate carrier gene (SLC19A1) is associated with an increased risk of neural tube defects (NTDs). However, the interaction between the SLC19A1 gene variant and maternal fever exposure and NTD risk remains unknown. The aim of this study was to investigate whether the risk for NTDs was influenced by the interactions between the SLC19A1 (rs1051266) variant and maternal first trimester fever.

Methods

We investigated the potential interaction between maternal first trimester fever and maternal or offspring SLC19A1 polymorphism through a population‐based case–control study. One hundred and four nuclear families with NTDs and 100 control families with nonmal newborns were included in the study. SLC19A1 polymorphism was determined using polymerase chain reaction–restricted fragment length polymorphism.

Results

Mothers who had the GG/GA genotype and first trimester fever had an elevated risk of NTDs (adjusted odds ratio, 11.73; 95% confidence interval, 3.02–45.58) as compared to absence of maternal first trimester fever and AA genotype after adjusting for maternal education, paternal education, and age, and had a significant interactive coefficient (γ = 3.17) between maternal GG/GA genotype and first trimester fever. However, there was no interaction between offspring's GG/GA genotype and maternal first trimester fever (the interactive coefficient γ = 0.97) after adjusting for confounding factors.

Conclusion

Our findings suggested that the risk of NTDs was potentially influenced by a gene–environment interaction between maternal SLC19A1 rs1051266 GG/GA genotype and first trimester fever. Maternal GG/GA genotype may strengthen the effect of maternal fever exposure on NTD risk in this Chinese population. Birth Defects Research (Part A) 103:3–11, 2015. © 2014 Wiley Periodicals, Inc.
A novel method for simulating insulin mediated GLUT4 translocation
Authors: Jezewski Andrew J. , Larson Joshua J. , Wysocki Beata , Davis Paul H. , Wysocki Tadeusz
Published: June 2014

Glucose transport in humans is a vital process which is tightly regulated by the endocrine system. Specifically, the insulin hormone triggers a cascade of intracellular signals in target cells mediating the uptake of glucose. Insulin signaling triggers cellular relocalization of the glucose transporter protein GLUT4 to the cell surface, which is primarily responsible for regulated glucose import. Pathology associated with the disruption of this pathway can lead to metabolic disorders, such as type II diabetes mellitus, characterized by the failure of cells to appropriately uptake glucose from the blood. We describe a novel simulation tool of the insulin intracellular response, incorporating the latest findings regarding As160 and GEF interactions. The simulation tool differs from previous computational approaches which employ algebraic or differential equations; instead, the tool incorporates statistical variations of kinetic constants and initial molecular concentrations which more accurately mimic the intracellular environment. Using this approach, we successfully recapitulate observed in vitro insulin responses, plus the effects of Wortmannin‐like inhibition of the pathway. The developed tool provides insight into transient changes in molecule concentrations throughout the insulin signaling pathway, and may be employed to identify or evaluate potentially critical components of this pathway, including those associated with insulin resistance. In the future, this highly tractable platform may be useful for simulating other complex cell signaling pathways. Biotechnol. Bioeng. 2014;111: 2454–2465. © 2014 Wiley Periodicals, Inc.
Jasmonsäure – ein universelles Pflanzenhormon
Authors: Wasternack Claus , Hause Bettina
Published: June 2014

Pflanzen müssen gegen vielfältige biotische und abiotische Umwelteinflusse eine Abwehr aufbauen. Aber gleichzeitig müssen sie wachsen und sich vermehren. Jasmonate sind neben anderen Hormonen ein zentrales Signal bei der Etablierung von Abwehrmechanismen, aber auch Signal von Entwicklungsprozessen wie Blüten‐ und Trichombildung, sowie der Hemmung von Wachstum. Biosynthese und essentielle Komponenten der Signaltransduktion von JA und seinem biologisch aktiven Konjugat JA‐Ile sind gut untersucht. Der Rezeptor ist ein Proteinkomplex, der “JA‐Ile‐Wahrnehmung” mit proteasomalem Abbau von Repressorproteinen verbindet. Dadurch können positiv agierende Transkriptionsfaktoren wirksam werden und vielfältige Genexpressionsänderungen auslösen. Dies betrifft die Bildung von Abwehrproteinen, Enzymen der JA‐Biosynthese und Sekundärstoffbildung, und Proteinen von Signalketten und Entwicklungsprozessen. Die Kenntnisse zur JA‐Ile‐Wirkung werden in Landwirtschaft und Biotechnologie genutzt.
Discovery of Protein Disulfide Isomerase P5 Inhibitors that Reduce the Secretion of MICA from Cancer Cells
Authors: Horibe Tomohisa , Torisawa Aya , Okuno Yukiko , Kawakami Koji
Published: June 2014

In order to regulate the activity of P5, which is a member of the protein disulfide isomerase family, we screened a chemical compound library for P5‐specific inhibitors, and identified two candidate compounds (anacardic acid and NSC74859). Interestingly, anacardic acid inhibited the reductase activity of P5, but did not inhibit the activity of protein disulfide isomerase (PDI), thiol‐disulfide oxidoreductase ERp57, or thioredoxin. NSC74859 inhibited all these enzymes. When we examined the effects of these compounds on the secretion of soluble major histocompatibility complex class‐I‐related gene A (MICA) from cancer cells, anacardic acid was found to decrease secretion. In addition, anacardic acid was found to reduce the concentration of glutathione up‐regulated by the anticancer drug 17‐demethoxygeldanamycin in cancer cells. These results suggest that anacardic acid can both inhibit P5 reductase activity and decrease the secretion of soluble MICA from cancer cells. It might be a novel and potent anticancer treatment by targeting P5 on the surface of cancer cells.
Biosynthesis of Nudicaulins: A 13CO2‐Pulse/Chase Labeling Study with Papaver nudicaule
Authors: Tatsis Evangelos C. , Eylert Eva , Maddula Ravi Kumar , Ostrozhenkova Elena , Svatoš Aleš , Eisenreich Wolfgang , Schneider Bernd
Published: June 2014

Nudicaulins are unique alkaloids responsible for the yellow color of the petals of some papaveraceaous plants. To elucidate the unknown biosynthetic origin of the skeleton, a 13CO2‐pulse/chase experiment was performed with growing Papaver nudicaule plants. 13C NMR analysis revealed more than 20 multiple 13C‐enriched isotopologues in nudicaulins from the petals of 13CO2‐labeled plants. The complex labeling pattern was compared with the isotopologue composition of a kaempferol derivative that was isolated from petals of the same 13CO2‐labeled plants. The deconvolution of the labeling profiles indicated that the nudicaulin scaffold is assembled from products or intermediates of indole metabolism, the phenylpropanoid pathway, and the polyketide biosynthesis. Naringenin‐type compounds and tryptophan/tryptamine are potential substrates for the condensation reaction finally generating the aglycone skeleton of nudicaulins.
Synthesis of Platinum Nanoparticles by using Molybdenum Disulfide as a Template and its Application to Enzyme‐like Catalysis
Authors: Duan Kaiyue , Du Yongling , Feng Qingliang , Ye Xiaoliang , Xie Hong , Xue Muyin , Wang Chunming
Published: June 2014

Platinum nanoparticles were synthesized with molybdenum disulfide (MoS2) as a template through a facile hydrothermal method. The as‐prepared nanocomposites (Pt‐MoS2) were characterized by TEM, HRTEM, electrochemical impedance spectroscopy, and X‐ray photoelectron spectroscopy, and they were then used to fabricate a biosensor for enzyme‐like catalysis of hydrogen peroxide (H2O2). The electrochemical activity for the reduction reactions of H2O2 was evaluated in N2‐saturated phosphate buffer solution. The cyclic voltammetry and amperometry results demonstrated that the biosensor modified by the nanocomposites exhibited a fast amperometric response and excellent electrocatalytic activity for reduction of H2O2 with a wide linear range from 0.004 to 48.5 mM and a low detection limit of 0.001 mM at 3σ. Thus, the present work indicates that Pt nanoparticles can be synthesized on the surface of few‐layer MoS2 owing to interfacial PtS bonds and that the composites show a clear enhancement in the catalytic activity relative to that of the platinum nanoparticles alone. This method provides a new way to prepare metal nanoparticles for extensive applications in the field of catalysis.
Chiral Organoborane Lewis Pairs Derived from Pyridylferrocene
Authors: Chen Jiawei , Lalancette Roger A. , Jäkle Frieder
Published: June 2014

In an effort to develop a new class of redox‐active chiral Lewis pairs, pyridine and borane moieties with different steric and electronic properties were introduced onto a planar chiral 1,2‐disubstituted ferrocene framework. Metathesis of lithiated, stannylated, or mercuriated pyridylferrocenes with boron halides afforded (pR)‐2‐[bis(pentafluorophenyl)boryl]‐1‐(3,5‐dimethylpyrid‐2‐yl)ferrocene (4‐Pf), (pR)‐2‐[dimesitylboryl]‐1‐(3,5‐dimethylpyrid‐2‐yl)ferrocene (4‐Mes), (pS)‐2‐(bis(pentafluorophenyl)boryl)‐1‐(2‐trimethylsilylpyrid‐6‐yl)ferrocene (5‐Pf), or (pS)‐2‐[dimesitylboryl]‐1‐(2‐trimethylsilylpyrid‐6‐yl)ferrocene (5‐Mes). The borylated products were analyzed by multinuclear NMR spectroscopy, HRMS, and single‐crystal X‐ray diffraction. Chiral HPLC and optical‐rotation measurements were employed to assess the stereoselectivity of the borylation process and to establish the correct stereochemical assignments. The strength of the B–N interactions were investigated in solution and in the solid state. Compounds 4‐Pf and 4‐Mes formed robust ‘closed’ BN heterocyclic systems that proved to be perfectly stable to air and moisture, whereas 5‐Pf established a dynamic equilibrium, in which the BN heterocycle was observed exclusively at room temperature, but opened up at high temperature according to 19F NMR exchange spectroscopy data. As a consequence, 5‐Pf reacted readily with a molecule of water to generate a ring‐opened pyridinium borate. The combination of bulky borane and bulky pyridyl groups in 5‐Mes led to a completely ‘open’ frustrated Lewis pair system with uncomplexed pyridine and borane groups, even at room temperature. Electrochemical studies were performed and the effect of preparative ferrocene oxidation on the structural features was also explored.
1,10‐Phenanthroline and Non‐Symmetrical 1,3,5‐Triazine Dipicolinamide‐Based Ligands For Group Actinide Extraction
Authors: Bisson Julia , Dehaudt Jérémy , Charbonnel Marie‐Christine , Guillaneux Denis , Miguirditchian Manuel , Marie Cécile , Boubals Nathalie , Dutech Guy , Pipelier Muriel , Blot Virginie , Dubreuil Didier
Published: June 2014

The synthesis and evaluation of new extractants for spent nuclear fuel reprocessing are described. New bitopic ligands constituted of phenanthroline and 1,3,5‐triazine cores functionalized by picolinamide groups were designed. Synthetic routes were investigated and optimized to obtain twelve new polyaza‐heterocyclic ligands. In particular, an efficient and versatile methodology was developed to access non‐symmetric 2‐substituted‐4,6‐di(6‐picolin‐2‐yl)‐1,3,5‐triazines from the 1,3,5‐triazapentadiene precursor in the presence of anhydride reagents. Extraction studies showed the ability of both ligand series to extract and separate actinides selectively at different oxidation states (UVI, NpV,VI, AmIII, CmIII, and PuIV) from an acidic solution (3 M HNO3). Phenanthroline‐based ligands show the most promising efficiency for use in the group actinide extraction (GANEX) process due to a higher number of donor nitrogen atoms and a suitable pre‐organization of the dipicolinamide‐1,10‐phenanthroline architecture.
Ring Opening and Bidentate Coordination of Amidinate Germylenes and Silylenes on Carbonyl Dicobalt Complexes: The Importance of a Slight Difference in Ligand Volume
Authors: Cabeza Javier A. , García‐Álvarez Pablo , Pérez‐Carreño Enrique , Polo Diego
Published: June 2014

The reactions of [Co2(CO)8] with one equiv of the benzamidinate (R2bzam) group‐14 tetrylenes [M(R2bzam)(HMDS)] (HMDS=N(SiMe3)2; 1: M=Ge, R=iPr; 2: M=Si, R=tBu; 3: M=Ge, R=tBu) at 20 °C led to the monosubstituted complexes [Co2{κ1MM(R2bzam)(HMDS)}(CO)7] (4: M=Ge, R=iPr; 5: M=Si, R=tBu; 6: M=Ge, R=tBu), which contain a terminal κ1M–tetrylene ligand. Whereas the Co2Si and Co2Ge tert‐butyl derivatives 5 and 6 are stable at 20 °C, the Co2Ge isopropyl derivative 4 evolved to the ligand‐bridged derivative [Co2{μ‐κ2Ge,N‐Ge(iPr2bzam)(HMDS)}(μ‐CO)(CO)5] (7), in which the Ge atom spans the CoCo bond and one arm of the amidinate fragment is attached to a Co atom. The mechanism of this reaction has been modeled with the help of DFT calculations, which have also demonstrated that the transformation of amidinate‐tetrylene ligands on the dicobalt framework is negligibly influenced by the nature of the group‐14 metal atom (Si or Ge) but is strongly dependent upon the volume of the amidinate NR groups. The disubstituted derivatives [Co2{κ1MM(R2bzam)(HMDS)}2(CO)6] (8: M=Ge, R=iPr; 9: M=Si, R=tBu; 10: M=Ge, R=tBu), which contain two terminal κ1M–tetrylene ligands, have been prepared by treating [Co2(CO)8] with two equiv of 1–3 at 20 °C. The IR spectra of 8–10 have shown that the basicity of germylenes 1 and 3 is very high (comparable to that of trialkylphosphanes and 1,3‐diarylimidazol‐2‐ylidenes), whereas that of silylene 2 is even higher.
Catalytic Self‐Propulsion of Supramolecular Capsules Powered by Polyoxometalate Cargos
Authors: del Mercato Loretta L. , Carraro Mauro , Zizzari Alessandra , Bianco Monica , Miglietta Ruggero , Arima Valentina , Viola Ilenia , Nobile Concetta , Sorarù Antonio , Vilona Debora , Gigli Giuseppe , Bonchio Marcella , Rinaldi Rosaria
Published: June 2014

Multicompartment, spherical microcontainers were engineered through a layer‐by‐layer polyelectrolyte deposition around a fluorescent core while integrating a ruthenium polyoxometalate (Ru4POM), as molecular motor, vis‐à‐vis its oxygenic, propeller effect, fuelled upon H2O2 decomposition. The resulting chemomechanical system, with average speeds of up to 25 μm s−1, is amenable for integration into a microfluidic set‐up for mixing and displacement of liquids, whereby the propulsion force and the resulting velocity regime can be modulated upon H2O2‐controlled addition.
Extending Documentation‐Based Models towards an Efficient Integration into Commercial Process Simulators
Authors: Merchan Victor Alejandro , Tolksdorf Gregor , Kraus Robert , Wozny Günter
Published: June 2014

In this contribution an extension of the principle of modeling in the documentation level towards the model integration in process modeling tools is presented. The definition of documentation‐based, problem‐specific interfaces allows a highly specific code generation of customized user models, including physical property calls and port definitions, while keeping the model development at a tool‐independent level. Two case studies concerning the rigorous model development and simulation of multiphase liquid systems show the potential of this approach.
High‐Throughput Multiplexing Gas Chromatography
Authors: Siegle Alexander F. , Trapp Oliver
Published: June 2014

Die Anwendung von Informationstechnologie in der Gaschromatographie wird vorgestellt. Multiplexing‐Gaschromatographie steigert Auslastungsgrad, Signal/Rausch‐Verhältnis und ermöglicht außergewöhnlich hohe Probendurchsätze. Parameter wie Sequenzlänge, Modulationsintervall sowie Anzahl wiederholter Injektionen im Hochdurchsatzmodus bestimmen die Leistungsfähigkeit dieser Methode. Die vorgestellte Technik eröffnet neue Perspektiven in der Prozessanalytik durch kontinuierliche Überwachung eines chemischen Prozesses bei gleichzeitiger Analyse aller vorhandenen Analyte.