bluuebunny/crossref_metadata_2025 huggingface dataset:
Mobile Intelligence - Um arcabouço para análise e visualização de dados tempo-espaciais originados por dispositivos móveis - DOI 10.5752/P.2316-9451.2013v1n2p45
Authors: Miranda Junior Pasteur Ottoni  de , Abreu João Francisco de
Published: May 2018

Dados tempo-espaciais são usualmente provenientes de dispositivos móveis equipados com sistemas de posicionamento global (GPS) e são gerados por carros, caminhões, ônibus, trens, aviões, navios, telefones celulares, dentre outros. Esses dados são úteis porque permitem localização e rastreamento. No entanto, uma grande quantidade de conhecimento pode ser extraída por meio de uma análise mais profunda deles, uma vez que tal conhecimento não é facilmente obtido por simples inspeção, pois esses bancos de dados são enormes. Este artigo apresenta um arcabouço para extração, processamento, análise e visualização de dados tempo-espaciais, de modo que se possa deles extrair inteligência. Este arcabouço é composto de ferramentas para extração e processamento de dados tempo-espaciais, uma infraestrutura de bancos de dados multidimensionais usados em data warehouses com extensões espaciais que analisa dados em muitas dimensões e níveis de agregação, uma ferramenta para a execução de consultas sobre paradas e movimentos de dispositivos móveis e um conjunto de algoritmos de mineração de dados espaciais, para extrair padrões de trajetória, classiﬁcação, regras de associação e clustering de trajetórias.
Efectos de un programa de actividad física en la composición corporal de escolares de 3-5 años
Authors: López Sánchez G. F. , Borrego Balsalobre F. J. , Díaz Suárez A.
Published: May 2018

Objetivos: Este artículo se centra en estudiar los efectos de un programa de actividad física sobre la composición corporal de ungrupo de escolares. Método: Han participado 36 escolares (20 niños y 16 niñas), entre los 3 y los 5 años de edad. Las variables estudiadas han sido: masa grasa, masa libre de grasa, IMC (Índice de Masa Corporal), ICC (Índice Cintura/Cadera). El análisis de la composición corporal se ha realizado mediante bioimpedancia eléctrica, por medio del Monitor de grasa corporal Tanita BC 418-MA Segmental. El procedimiento ha sido: pre-test, intervención y pos-test. La intervención ha consistido en 3 días a la semana de actividad física de alta intensidad, 15 minutos al día, durante 12 semanas. Resultados y conclusiones: Mejoras significativas en la masa grasa (Sig. < 0.05). No se han encontrado mejoras significativas en la masa libre de grasa, el IMC y el ICC.
Enjeux de la science et de la gouvernance de la biodiversité
Authors: Loreau Michel
Published: May 2018

Ouvrant la réflexion sur les enjeux de la perte massive de la biodiversité, l’article s’appuie sur la question élémentaire de l’importance de la diversité biologique pour l’homme, à la fois sur le plan économique, biologique et éthique. La maîtrise de la nature par l’homme se révèle être une illusion. La réalité étant celle de l’interaction, il est permis de dire que les sociétés humaines agissent sur leurs propres conditions en modifiant les équilibres biologiques pour satisfaire leurs besoins, sans pour autant intégrer cette interaction fondamentale dans l’équation d’un rapport viable entre l’homme et la nature. L’approche récente par le biais des analyses des services écologiques constitue à cet égard un progrès sensible. Il aboutit néanmoins au constat de l’impossibilité pour l’humanité de se substituer aux mécanismes naturels permettant de tirer les services de la nature nécessaires à sa survie. Plutôt que de prétendre contrôler et maîtriser la nature à tout prix, l’homme devrait apprendre à se reconnaître comme une partie consciente de la nature et à vivre avec la vie qui l’entoure. Cet apprentissage soulève des défis scientifiques, humains et de gouvernance. L’article prône la nécessité d’une science de la biodiversité intégrée et non plus éclatée, condition essentielle pour l’élaboration de politiques économiques et sociales qui intègrent la viabilité de l’utilisation des ressources naturelles et des services qu’elles procurent.
Les limites de l’évaluation économique de la biodiversité
Authors: Maris Virginie , Revéret Jean-Pierre
Published: May 2018

Devant le constat du déclin toujours plus rapide de la diversité biologique et les limites des ressources disponibles pour l’enrayer, il est nécessaire de déterminer quels moyens devraient être engagés dans sa protection. Pour ce faire, une méthode efficace serait d’évaluer les bénéfices tirés de la biodiversité afin d’estimer rationnellement les coûts légitimes de sa protection. L’évaluation économique, qui se présente d’emblée sur un mode quantitatif, serait alors un outil précieux. Dans ce texte, nous présentons différentes méthodes d’évaluation économique de la biodiversité ainsi que certaines de leurs limites méthodologiques. Par la suite, nous montrons qu’en dépit de ses avantages pratiques, l’évaluation économique échoue à représenter l’ensemble des valeurs en jeu dans la protection de la biodiversité. Nous décrivons alors trois types de valeurs incommensurables avec des bénéfices économiques : la valeur de legs, qui renvoie aux obligations de transmission du patrimoine naturel dont nous avons hérité ; la valeur d’existence, qui renvoie à la considération morale d’intérêts autres que ceux des êtres humains ; la valeur de transformation, qui renvoie à la capacité d’examiner et de critiquer nos préférences et inclinaisons afin d’inclure celles-ci dans une vision du monde rationnelle et cohérente. Pour conclure, nous plaidons en faveur de l’élaboration de méthodes de concertation et d’évaluation participatives et pluralistes permettant de rendre compte de la diversité et de l’hétérogénéité des valeurs de la biodiversité.
Everyday Ethics: Framing youth participation in organizational practice
Authors: Driskell David , Kudva Neema
Published: May 2018

Much of the literature on ethical issues in child and youth participation has drawn on the episodic experiences of participatory research efforts in which young people’s input has been sought, transcribed and represented. This literature focuses in particular on the power dynamics and ethical dilemmas embedded in time-bound adult/child and outsider/insider relationships. While we agree that these issues are crucial and in need of further examination, it is equally important to examine the ethical issues embedded within the “everyday” practices of the organizations in and through which young people’s participation in community research and development often occurs (e.g., community-based organizations, schools and municipal agencies). Drawing on experience from three summers of work in promoting youth participation in adult-led organizations of varying purpose, scale and structure, a framework is postulated that presents participation as a spatial practice shaped by five overlapping dimensions. The framework is offered as a point of discussion and a potential tool for analysis in examining ethical issues for young people’s participation in relation to organizational practice.
Perspectives féministes en éthique des relations internationales
Authors: Chung Ryoa
Published: May 2018

Dans le cadre de cet article, je veux démontrer la nécessité de développer et d’incorporer les perspectives féministes dans le champ de l’éthique des relations internationales à travers l’examen des contributions respectives de J. A. Tickner, C. MacKinnon, S. Ruddick et M. Nussbaum. Mon hypothèse générale consiste à arguer que la force critique des perspectives féministes en théorie politique représente non seulement une ouverture épistémologique incontournable, mais que celles-ci ouvrent la voie à des méthodes d’investigation et de conceptualisation que l’on doit explorer en vue d’enrichir les théories de justice globale d’une portée pratique plus grande.
Développement durable : quelques points litigieux
Authors: Larrère Catherine
Published: May 2018

Le développement durable a pour objectif de concilier des exigences diverses, sinon antagoniques : l’économique, le social, l’environnemental. On peut donc se demander s’il répond vraiment aux intuitions qui sont au point de départ de la conscience écologique. Nous en dégageons trois, dans trois domaines : l’exigence de protection de la nature, la conviction que la solution à la crise environnementale ne peut pas être purement technique, et l’insistance sur la dimension sociale, et pas seulement naturelle, de la crise environnementale. Chacune de ces exigences donne lieu à des débats conflictuels : préservation contre conservation, souci éthique contre optimisme technologique, exigence sociale et politique contre traitement scientiste des questions environnementales. De l’examen de ces litiges, il ressort que l’avenir du développement durable passe par une reformulation du concept de nature.
Financing higher education: the case for a graduate tax
Authors: Dietsch Peter
Published: May 2018

The debate whether university education should be “free” seems misconstrued. Even in a system without tuition fees, someone will have to foot the bill. This paper argues that from the viewpoint of justice, a strong case can be made in higher education for adopting the beneficiary pays principle, and for institutionalising it in the form of a graduate tax. My evaluation from the perspective of justice will focus on the comparison between a “free” university system funded through the general tax system on the one hand, and one financed through a graduate tax on the other. On the beneficiary pays principle defended here, the regressive nature of the general-tax-funded higher education system renders it unjust. Furthermore, I believe we have three reasons to favour a graduate tax in practice. First, I will suggest that it does a better job at implementing the beneficiary pays principle. Second, I will argue that even though the distributive outcome of a corrected general-tax-funded education may be just, it is unlikely to be perceived to be just. A third point of comparison between the two approaches to fund higher education will be international mobility, which will reinforce the case for a graduate tax from the viewpoint of justice.
Seasonal dynamics of terrestrial vertebrate abundance between Amazonian flooded and unflooded forests
Authors: Costa Hugo C M , Peres Carlos A , Abrahams Mark I
Published: May 2018

The flood pulse is the main factor structuring and differentiating the ecological communities of Amazonian unflooded (terra firme) and seasonally-flooded (várzea) forests as they require unique adaptations to survive the prolonged annual floods. Therefore, várzea and terra firme forests hammer out a spatio-temporal mosaic of resource availability, which may result in landscape scale seasonal movements of terrestrial vertebrates between adjacent forest types. Yet the lateral movements of terrestrial vertebrates between hydrologically distinct neighbouring forest types exhibiting staggered resource availability remains poorly understood, despite the important implications of this spatial dynamic for the ecology and conservation of forest wildlife. We examined the hypothesis of terrestrial fauna seasonal movements between two adjacent forest types at two contiguous sustainable-use forest reserves in Western Brazilian Amazonia. We used camera trapping data on the overall species richness, composition, and abundance of nine major vertebrate trophic guilds to infer on terrestrial vertebrate movements as a function of seasonal changes in floodplain water level. Species richness differed in neighboring terra firme forests between the high-and low-water phases of the flood pulse and terra firme forests were more species rich than várzea forests. There were clear differences in species composition between both forest types and seasons. Generalized Linear Models showed that water level was the main factor explaining aggregate abundance of all species and three trophic guilds. Our results indicate that the persistence of viable populations of large terrestrial vertebrates adjacent to major Amazonian rivers requires large, well-connected forest landscapes encompassing different forest types to ensure large-scale lateral movements by forest wildlife.
A brief introduction to mixed effects modelling and multi-model inference in ecology
Authors: Harrison Xavier A. , Donaldson Lynda , Correa-Cano Maria Eugenia , Evans Julian , Fisher David N. , Goodwin Cecily E.D. , Robinson Beth S. , Hodgson David J. , Inger Richard
Published: May 2018

The use of linear mixed effects models (LMMs) is increasingly common in the analysis of biological data. Whilst LMMs offer a flexible approach to modelling a broad range of data types, ecological data are often complex and require complex model structures, and the fitting and interpretation of such models is not always straightforward. The ability to achieve robust biological inference requires that practitioners know how and when to apply these tools. Here, we provide a general overview of current methods for the application of LMMs to biological data, and highlight the typical pitfalls that can be encountered in the statistical modelling process. We tackle several issues regarding methods of model selection, with particular reference to the use of information theory and multi-model inference in ecology. We offer practical solutions and direct the reader to key references that provide further technical detail for those seeking a deeper understanding. This overview should serve as a widely accessible code of best practice for applying LMMs to complex biological problems and model structures, and in doing so improve the robustness of conclusions drawn from studies investigating ecological and evolutionary questions.
A survey on sleep assessment methods
Authors: Ibáñez Vanessa , Silva Josep , Cauli Omar
Published: May 2018

Purpose

A literature review is presented that aims to summarize and compare current methods to evaluate sleep.

Methods

Current sleep assessment methods have been classified according to different criteria; e.g., objective (polysomnography, actigraphy…) vs. subjective (sleep questionnaires, diaries…), contact vs. contactless devices, and need for medical assistance vs. self-assessment. A comparison of validation studies is carried out for each method, identifying their sensitivity and specificity reported in the literature. Finally, the state of the market has also been reviewed with respect to customers’ opinions about current sleep apps.

Results

A taxonomy that classifies the sleep detection methods. A description of each method that includes the tendencies of their underlying technologies analyzed in accordance with the literature. A comparison in terms of precision of existing validation studies and reports.

Discussion

In order of accuracy, sleep detection methods may be arranged as follows:

Questionnaire < Sleep diary < Contactless devices < Contact devices < Polysomnography

A literature review suggests that current subjective methods present a sensitivity between 73% and 97.7%, while their specificity ranges in the interval 50%–96%. Objective methods such as actigraphy present a sensibility higher than 90%. However, their specificity is low compared to their sensitivity, being one of the limitations of such technology. Moreover, there are other factors, such as the patient’s perception of her or his sleep, that can be provided only by subjective methods. Therefore, sleep detection methods should be combined to produce a synergy between objective and subjective methods. The review of the market indicates the most valued sleep apps, but it also identifies problems and gaps, e.g., many hardware devices have not been validated and (especially software apps) should be studied before their clinical use.
APLICAÇÃO DA TÉCNICA DE ELETROCOAGULAÇÃO PARA A REMOÇÃO DA CORANTE TÊXTIL
Authors: Algeri Alessandra , Vaghetti Luchese Augusto , Mendes Morini Pamella , Sehn Elizandra
Published: May 2018

O objetivo deste trabalho consistiu em determinar o tempo operacional e a densidade de corrente elétrica que otimizassem a remoção da cor de um efluente sintético à base de corante vermelho reativo, por Delineamento Composto Central Rotacional (DCCR). A partir das condições otimizadas foi realizada uma análise de custos operacionais em função da energia gasta e também do consumo de eletrodo. As condições ótimas e os custos operacionais foram determinados para os comprimentos de onda de 515 e 543 nm. A região ótima de remoção, para os dois comprimentos de onda, ficou entre 47 e 51,1 minutos e 360-440 A m-2, com valores teóricos de remoção estimados entre 70 e 80%. O consumo de eletrodos e de energia nos tempos e densidade de correntes otimizados encontrados ficou em 1,71 g L-1 e 0,0077 Wh m-3para o comprimento de onda de 515 nm e 1,73 g L-1 e 0,0073 Wh m-3 para o de 543 nm, resultando nas equações: , para o comprimento de 515 nm e  para o 543 nm, nos quais a corresponde ao custo de energia (em R$.kWh-1) e b ao custo mássico da placa (em R$.kg eletrodo-1).
PERCEPÇÃO AMBIENTAL DA POPULAÇÃO DA FUNDAÇÃO UNIVERSIDADE REGIONAL DE BLUMENAU (FURB)
Authors: Gotti Andressa , Gohr Pinheiro Ivone
Published: May 2018

A gestão ambiental na Fundação Universidade Regional de Blumenau (FURB) começou a ser implantada em 1998 e atualmente existe um sistema de gestão ambiental (SGA), porém ocorreram mudanças ao longo do período transcorrido. Constatada esta situação, o objetivo deste trabalho foi avaliar a percepção ambiental da população da FURB. Esta avaliação se deu a partir da aplicação de um formulário semiestruturado a uma amostra estratificada em docentes, discentes e técnico-administrativos. O formulário possuía questões abertas, de múltipla escolha e combinação dicotômica, e questões abertas. Os resultados apontaram que 85% dos respondentes de cada estrato da amostra possui interesse por notícias e reportagens sobre questão ambientais, preferindo encontrá-las no site da universidade, em e-mails e em cartazes. Os problemas ambientais que mais preocupam são a escassez e a poluição da água independente do estrato amostral considerado. Aproximadamente metade dos técnico-administrativos e docentes afirmaram perceber as ações da universidade voltadas para a economia de água e energia, enquanto que somente por volta de 20% dos discentes afirmaram percebê-las. Destas ações as que são mais percebidas são os cartazes e o sistema de torneiras econômicas. No que diz respeito ao conhecimento da política ambiental da FURB um terço dos técnico-administrativos e docentes a conhecem contra apenas 4% dos discentes, enquanto que o SGA da FURB é bem mais conhecido uma vez que 64, 46, e 7% dos docentes, técnico-administrativos e discentes, respectivamente o conhecem. Os respondentes ao se deparar com assuntos ambientais em meios de comunicação possuem uma visão pessimista e não percebem muitos avanços e melhorias na área ambiental. Como o SGA e a política ambiental da FURB são muito pouco conhecidos entre os discentes bem como são eles os que menos percebem as ações voltadas para a sustentabilidade esse estrato é o que mais necessita de atenção. Como foi observado que a comunicação digital e on-line é a preferida, este é um caminho a ser considerado para utilizar conceitos e diretrizes ambientais ofertados pelo SGA já existente junto com a educação ambiental para atingir todos os três estratos já que se constatou que a maioria se sente responsável pela qualidade e integridade do meio ambiente.
CARBONO E NITROGÊNIO NAS CLASSES DE AGREGADOS DE UM SOLO SUBMETIDO À APLICAÇÃO DE CAMA DE FRANGO
Authors: Maas Kelly Dayana Benedet , Vieira Cristiane Ramos , Weber Oscarlina Lúcia dos Santos , Magalhães Sulamirtes Suellen de Amorim
Published: May 2018

A matéria orgânica é composta basicamente de carbono e de nitrogênio e um dos seus papéis é a estruturação do solo. Portanto, seu revolvimento ou retirada da área de plantio pode prejudicar a qualidade física do solo. Diante dessa característica, desenvolveu-se estudo para verificar a influência dos teores de carbono e de nitrogênio nos agregados do solo submetido à aplicação de cama de frango. O estudo foi realizado em área submetida ao plantio direto e adubada com cama de frango. A amostragem do solo foi realizada em mini trincheiras de 60x60x60 cm em delineamento inteiramente casualizado, utilizando parcelas subdivididas em três profundidades: 0-10 cm, 10-20 cm e 20-30 cm. A separação das classes de agregados foi via seca. Nas amostras de cada classe determinaram-se os teores de C e de N, verificando-se que os teores de C, N e de matéria orgânica foram superiores nas camadas superficiais do solo. Portanto, o acúmulo de matéria orgânica no sistema de plantio direto com aplicação de cama de frango pode melhorar a estabilidade dos agregados e assim, a estrutura do solo.
Tau filaments in neurodegenerative diseases
Authors: Goedert Michel
Published: May 2018

The ordered assembly of Tau protein into abnormal filamentous inclusions is a defining characteristic of many human neurodegenerative diseases. Thirty years ago, we reported that Tau is an integral component of the intraneuronal filaments of Alzheimer's disease. All six brain Tau isoforms make up those filaments. Twenty years ago, we and others showed that mutations in MAPT, the Tau gene, cause familial forms of frontotemporal dementia, thus proving that dysfunction of Tau protein is sufficient to cause neurodegeneration and dementia. More recently, we showed that high‐resolution structures of Tau filaments from human brain can be determined by electron cryo‐microscopy. These filaments may form the seeds that underlie the prion‐like properties of aggregated tau.
Command governor‐based adaptive control for dynamical systems with matched and unmatched uncertainties
Authors: Yayla Metehan , Arabi Ehsan , Kutay Ali Turker , Yucelen Tansel
Published: May 2018

In this paper, we propose a command governor‐based adaptive control architecture for stabilizing uncertain dynamical systems with not only matched but also unmatched uncertainties and achieving the desired command following performance of a user‐defined subset of the accessible states. In our proposed solution, online least‐squares solutions for the matched and unmatched parameters are obtained through integration method and they are employed in the adaptive control framework. Specifically, the matched uncertainty is identified and its effect upon the system behavior is entirely attenuated. Moreover, using the unmatched uncertainty approximation obtained through radial basis function neural networks, the command governor signal is designed to achieve the desired command following performance of the user‐defined subset of the accessible states. With this command governor‐based model reference adaptive control architecture, the tracking error of the selected states can be made arbitrarily small by judiciously tuning the design parameters. In addition to the analysis of the closed‐loop system stability using methods from the Lyapunov theory, our findings are also illustrated through numerical examples.
Flexible All‐Solid‐State Supercapacitors of High Areal Capacitance Enabled by Porous Graphite Foams with Diverging Microtubes
Authors: Li Weigu , Tekell Marshall C. , Liu Chang , Hethcock Jacob A. , Fan Donglei
Published: May 2018

The practical applications of wearable electronics rely on the successful development of flexible and integrable energy devices with small footprints. This work reports a completely new type of graphite foam made of strategically created superstructures with covalently attached diverging microtubes, and their applications as electrode supports for binder‐free and additive‐free flexible supercapacitors. Because of the enhanced volumetric surface areas compared to conventional graphite foams, a high loading of pseudocapacitive materials (Mn3O4, 3.91 mg cm−2, 78 wt%) is achieved. The supercapacitors provide areal capacitances as high as 820 mF cm−2 at 1 mV s−1, while still maintaining high rate capability and 88% retention of capacitance after 3000 continuous charging and discharging cycles. When assembled as all‐solid‐state flexible symmetric supercapacitors, they offer one of the highest full‐cell capacitances (191 mF cm−2) among similar manganese oxide/graphene foams, and retain 80% capacitance after 1000 mechanical cycles. The potential of such flexible supercapacitors is also manifested by directly powering electric nanomotors that can trace along letters “U” and T,” which is the first demonstration of flexible supercapacitors for wireless/portable nanomanipulation systems. This work could inspire a new paradigm in designing and creating 3D porous micro/nanosuperstructures for an array of self‐powered electronic and nanomechanical applications.
Electrowetting‐Induced Stiction Switch of a Microstructured Wire Surface for Unidirectional Droplet and Bubble Motion
Authors: Yan Yufeng , Guo Zhenyan , Zhang Xiaofang , He Linlin , Li Yan , Liu Kesong , Cai Jinhua , Tian Dongliang , Jiang Lei
Published: May 2018

Directional motion of fluid droplets is attracting considerable research attention. Despite much progress in this field, electrowetting‐based stiction switch that drives unidirectional transport of an underwater oil droplet or air bubble on a wire surface is still a challenge to realize. Here, a strategy to collect and unidirectionally transport an underwater oil droplet or air bubble on a porous polystyrene (PS) film‐coated copper wire surface through the combination of electrowetting‐induced stiction switch and buoyancy is demonstrated. The porous PS film‐coated copper wire fabricated by the breath figure method at a relative humidity of 75% can catch and hold an underwater oil droplet or air bubble without applied voltage. With increasing applied voltage, the stiction of the underwater oil droplet or air bubble on the porous PS film surface weakens because water increasingly wets the film surface. The underwater oil droplet or air bubble can move unidirectionally on the porous PS film‐coated wire surface upward or downward at a voltage larger than its critical voltage according to whether its density is lower or higher than that of water. This work should aid the development of devices displaying electrowetting‐based changes for use in fluid collection, manipulation, unidirectional transfer, release, and removal.
Shape Reconfiguration of a Biomimetic Elastic Membrane with a Switchable Janus Structure
Authors: Bai Jing , Shi Zixing , Yin Jie , Tian Ming , Qu Rongjun
Published: May 2018

A method for the fabrication of a biomimetic Janus composite membrane is reported here. This approach is based on a membrane with a vertical gradient crosslinking degree, which is achieved through UV light–induced dimerization of anthracene grafted on poly(styrene‐block‐butadiene‐block‐styrene) chains in the presence of carbon nanotubes. UV light penetration is controlled by the accretion of carbon nanotubes to ultimately tailor the heterogeneous crosslinking degree in thickness. This kind of Janus structure is applied here for shape actuation. Here, solvent or shape memory effect–induced shape morphing is obtained via the heterogeneous swelling (deswelling) abilities of, or internal stress from, the Janus structure. By tailoring the UV light irradiation time, the irradiated region and the prestrain, sophisticated and multiple types of shape morphing are programed. In addition, this type of Janus structure can shift back to the homogeneous structure via dedimerization of the anthracene dimers upon thermal treatment, which provides extensive freedom for the design of smart responsive actuators.
A Subtractive Photoresist Platform for Micro‐ and Macroscopic 3D Printed Structures
Authors: Zieger Markus M. , Müller Patrick , Blasco Eva , Petit Charlotte , Hahn Vincent , Michalek Lukas , Mutlu Hatice , Wegener Martin , Barner‐Kowollik Christopher
Published: May 2018

The selective removal of structural elements plays a decisive role in 3D printing applications enabling complex geometries. To date, the fabrication of complex structures on the microscale is severely limited by multistep processes. Herein, a subtractive photoresist platform technology that is transferable from microscopic 3D printing via direct laser writing to macroscopic structures via stereolithography is reported. All resist components are readily accessible and exchangeable, offering fast adaptation of the resist's property profile. The micro‐ and macroprinted structures can be removed in a facile fashion, without affecting objects based on standard photoresists. The cleavage is analyzed by time‐lapse optical microscopy as well as via in‐depth spectroscopic assessment. The mechanical properties of the printed materials are investigated by nanoindentation. Critically, the power of the subtractive resist platform is demonstrated by constructing complex 3D objects with flying features on the microscale.
Systematic Power Factor Enhancement in n‐Type NiETT/PVDF Composite Films
Authors: Menon Akanksha K. , Wolfe Rylan M. W. , Marder Seth R. , Reynolds John R. , Yee Shannon K.
Published: May 2018

Nickel ethenetetrathiolate (NiETT) coordination polymers are shown to exhibit high thermoelectric performance as pressed pellets. Because the material is insoluble, films are formed by fabricating a composite of the material in an inert polymer matrix, a process that adversely impacts thermoelectric properties. To date, a reliable and reproducible synthesis has not been reported, which was the motivation for a systematic study of the substeps involved to understand the reaction mechanism. The results of these studies yield optimized reaction conditions for high performance n‐type films, which are derived from empirical studies and material characterization. Herein, a reaction procedure is presented that gives reproducible properties when preparing batches in the 0.5–15 g range. The identity of the counterion, nickel equivalency, and oxidation extent are investigated, which provide insight into the synthetic reaction mechanism and the ligand‐centered oxidation process in these polymers. Optimized materials based on Na[NiETT] exhibit one of the highest n‐type thermoelectric performance for solution‐processed films reported to date, with power factors of 23 µW (m K)−2 (due to conductivities approaching 50 S cm−1) while maintaining their stability in ambient conditions.
Ultrasensitive Room‐Temperature Terahertz Direct Detection Based on a Bismuth Selenide Topological Insulator
Authors: Tang Weiwei , Politano Antonio , Guo Cheng , Guo Wanlong , Liu Changlong , Wang Lin , Chen Xiaoshuang , Lu Wei
Published: May 2018

Despite their huge application capabilities, millimeter‐ and terahertz‐wave photodetectors still face challenges in the detection scheme. Topological insulators (TIs) are predicted to be promising candidates for long‐wavelength photodetection, due to the presence of Dirac fermions in their topologically protected surface states. However, photodetection based on TIs is usually hindered by the large dark current, originating from the mixing of bulk states with topological surface states (TSSs) in most realistic samples of TIs. Here millimeter and terahertz detectors based on a subwavelength metal–TI–metal (MTM) heterostructure are demonstrated. The achieved photoresponse stems from the asymmetric scattering of TSS, driven by the localized surface plasmon‐induced terahertz field, which ultimately produces direct photocarriers beyond the interband limit. The device enables high responsivity in both the self‐powered and bias modes even at room temperature. The achieved responsivity is over 75 A/W, with response time shorter than 60 ms in the self‐powered mode. Remarkably, the responsivity increases by several orders of magnitude in the biased configuration, with the noise‐equivalent power (NEP) of 3.6 × 10−13 W Hz−1/2 and a detectivity of 2.17 × 1011 cm Hz−1/2 W−1 at room temperature. The detection performances open a way toward realistic exploitation of TIs for large‐area, real‐time imaging within long‐wavelength optoelectronics.
Engineering Solid Electrolyte Interphase for Pseudocapacitive Anatase TiO2 Anodes in Sodium‐Ion Batteries
Authors: Xu Zheng‐Long , Lim Kyungmi , Park Kyu‐Young , Yoon Gabin , Seong Won Mo , Kang Kisuk
Published: May 2018

Anatase TiO2 is considered as one of the promising anodes for sodium‐ion batteries because of its large sodium storage capacities with potentially low cost. However, the precise reaction mechanisms and the interplay between surface properties and electrochemical performance are still not elucidated. Using multimethod analyses, it is herein demonstrated that the TiO2 electrode undergoes amorphization during the first sodiation and the amorphous phase exhibits pseudocapacitive sodium storage behaviors in subsequent cycles. It is also shown that the pseudocapacitive sodium storage performance is sensitive to the nature of solid electrolyte interphase (SEI) layers. For the first time, it is found that ether‐based electrolytes enable the formation of thin (≈2.5 nm) and robust SEI layers, in contrast to the thick (≈10 nm) and growing SEI from conventional carbonate‐based electrolytes. First principle calculations suggest that the higher lowest unoccupied molecular orbital energies of ether solvents/ion complexes are responsible for the difference. TiO2 electrodes in ether‐based electrolyte present an impressive capacity of 192 mAh g−1 at 0.1 A g−1 after 500 cycles, much higher than that in carbonate‐based electrolyte. This work offers the clarified picture of electrochemical sodiation mechanisms of anatase TiO2 and guides on strategies about interfacial control for high performance anodes.
C4photosynthesis and transition of Kranz anatomy in cotyledons and leaves ofTetraena simplex
Authors: Muhaidat Riyadh , McKown Athena D. , Al Zoubi Mazhar , Bani Domi Zakariya , Otoum Osama
Published: May 2018

Premise of the Study

Tetraena simplexis an independently evolved C4species in the Zygophylloideae (Zygophyllaceae) and a characteristic forb of saline flats in hot and sandy desert habitats. During early ontogeny, the species had a morphological shift from planar cotyledons (dorsiventral symmetry) to terete, succulent leaves (radial symmetry). We tested whether this shift had a corresponding change in internal Kranz anatomy and tissue patterning.

Methods

For a comprehensive characterization of C4photosynthesis across early ontogeny inT. simplex, structural and ultrastructural anatomical properties and localization patterns, activities, and immunoblotting of key C4photosynthetic enzymes were compared in mesophyll and bundle sheath tissues in cotyledons and leaves.

Key Results

Cotyledons and leaves possessed different types of Kranz anatomy (atriplicoid type and a “Tetraena” variant of the kochioid type, respectively), reflecting the change in leaf morphology. In bundle sheath cells, key differences in ultrastructural features included increased organelle numbers and chloroplast thylakoid stacking. C4enzymes had strict tissue‐specific localization patterns within bundle sheath and mesophyll cells in both cotyledons and leaves. The decarboxylaseNAD‐MEmaintained the highest activity, increasing from cotyledons to leaves. This classifiedT.simplexas fully C4across ontogeny and a strictlyNAD‐MEbiochemical subtype.

Conclusions

Tetraena simplexcotyledons and leaves showed differences in Kranz type, with associated progression in ultrastructural features, and differing activities/expression levels of C4enzymes. Furthermore, leaves characterized a new “Tetraena” variation of the kochioid Kranz anatomy.
Lewis‐Base‐Catalyzed Domino Reaction of Morita–Baylis–Hillman Carbonates of Isatins with Enolizable Cyclic Carbonyl Compounds: Stereoselective Access to Spirooxindole‐Pyrans
Authors: Yadav Anubha , Banerjee Joyanta , Arupula Sanjeeva K. , Mobin Shaikh M. , Samanta Sampak
Published: May 2018

The present paper reports an efficient, organocatalytic, environmentally friendly and stereoselective [3+3] one‐pot allylic alkylation/oxa‐Michael reaction by involving a wide range of Morita–Baylis–Hillman (MBH) carbonates of isatins and several pharmacologically attractive enolizable C−H activated cyclic carbonyl compounds such as 1,3‐binucleophiles, namely pyrazolones, isoxazolones, 4‐hydroxyxoumarins, 4‐hydroxy‐6‐methyl‐α‐pyrone, lawsone and dimedone in a biomass‐derived 2‐MeTHF as green solvent catalyzed by DABCO as a solid Lewis‐base catalyst. This protocol delivers a unique class of medicinally promising spirooxindole‐fused‐dihydropyran scaffolds.
Chemo‐enzymatische Totalsynthese von Oxosorbicillinol, Sorrentanon, Rezishanon B und C, Sorbicatechol A, Bisvertinolon und (+)‐Epoxysorbicillinol
Authors: Sib Anna , Gulder Tobias A. M.
Published: May 2018

Die Sorbicillinoide sind eine große Familie fungaler Naturstoffe, die häufig sehr anspruchsvolle Molekülarchitekturen aufweisen. Abhängig von ihrer individuellen Struktur zeigen sie starke biologische Aktivitäten, die von Radikalfänger‐ und anti‐infektiven Eigenschaften bis hin zu Cytotoxizität reichen können. Trotz ihres daraus resultierenden, großen biomedizinischen Potenzials und des allgemeinen Interesses an diesen faszinierenden Strukturen aus dem Feld der Naturstoff‐Totalsynthese sind viele Sorbicillinoide zurzeit nicht präparativ zugänglich, was ihre eingehende biologische Charakterisierung und strukturelle Diversifizierung verhindert. Durch die Nutzung der rekombinanten Oxidoreduktase SorbC und einfach präparativ zugänglicher Sorbicillin‐artiger Vorstufen wurden enantioselektive, chemo‐enzymatische Ein‐Topf‐Syntheserouten zu einem breiten Spektrum an Sorbicillinoiden entwickelt. Dadurch wurden Totalsynthesen von Oxosorbicillinol, Sorrentanon, Rezishanon B und C, Sorbicatechol A, Bisvertinolon und (+)‐Epoxysorbicillinol ermöglicht.
Self‐Reporting Inhibitors: A Single Crystallization Process To Obtain Two Optically Pure Enantiomers
Authors: Ye Xichong , Cui Jiaxi , Li Bowen , Li Na , Zhang Jie , Wan Xinhua
Published: May 2018

Collection of two optically pure enantiomers in a single crystallization process can significantly increase the chiral separation efficiency but this is difficult to realize. Now a self‐reporting strategy is presented for visualizing the crystallization process by a dyed self‐assembled inhibitor made from the copolymers with tri(ethylene glycol)‐grafting polymethylsiloxane as the main chain and poly(N6‐methacryloyl‐l‐lysine) as side chains. When applied with seeds together for the fractional crystallization of conglomerates, the inhibitors can label the formation of the secondary crystals and guide the complete separation process of two enantiomers with colorless crystals as the first product and red crystals as the second. This method leads to high optical purity of d/l‐Asn⋅H2O (99.9 % ee for d‐crystals and 99.5 % for l‐crystals) in a single crystallization process. It requires a small amount of additives and shows excellent recyclability.
Isolierung schwer fassbarer Komplexe mit einer Aluminium‐Element‐Mehrfachbindung: Am Horizont zeichnet sich eine neue Aluminiumchemie ab
Authors: Bag Prasenjit , Weetman Catherine , Inoue Shigeyoshi
Published: May 2018

Die Synthese und Isolierung von stabilen Hauptgruppenkomplexen mit Mehrfachbindungen ist seit mehreren Dekaden von größtem Interesse. Eine Vielfalt solcher Komplexe wurde durch den Einsatz von sterisch anspruchsvollen Substituenten erhalten, die sowohl kinetische als auch thermodynamische Stabilität verleihen. Die meisten dieser Verbindungen haben außergewöhnliche strukturelle und elektronische Eigenschaften, die das klassische Konzept der kovalenten Mehrfachbindung auf die Probe stellen. Trotz der hohen natürlichen Häufigkeit von Aluminium sind entsprechende Verbindungen für dieses Element besonders selten. Die Stammverbindung Al2H2 (Dialumen) wurde mittels theoretischer Methoden als extrem instabil charakterisiert, weshalb Mehrfachbindungen mit Aluminium ein präparativ anspruchsvolles Ziel sind. Dieser Aufsatz bietet eine Zusammenstellung der neuesten Syntheseansätze und der Möglichkeiten zur Gestaltung von Ligandensystemen für die Isolierung von Komplexen mit homo‐ und heteroatomaren Aluminium‐Mehrfachbindungen. Außerdem wird die Reaktivität dieser neuartigen Verbindungen ausführlich diskutiert.
Rapid Photoactuation of a DNA Nanostructure using an Internal Photocaged Trigger Strand
Authors: Liu Minghui , Jiang Shuoxing , Loza Omar , Fahmi Nour Eddine , Šulc Petr , Stephanopoulos Nicholas
Published: May 2018

A reconfigurable DNA nano‐tweezer is reported that can be switched between a closed and open state with a brief pulse of UV light. In its initial state, the tweezer is held shut using a hairpin with a single‐stranded poly‐A loop. Also incorporated in the structure is a poly‐T trigger strand bearing seven photocaged residues. Upon illumination with 365 nm light, the cages are removed and the trigger strand hybridizes to the loop, opening the tweezer and increasing the distance between its arms from 4 to 18 nm. This intramolecular process is roughly 60 times faster than adding an external trigger strand, and provides a mechanism for the rapid interconversion of DNA nanostructures with light.
Amino Acid Assisted Incorporation of Dye Molecules within Calcite Crystals
Authors: Marzec Bartosz , Green David C. , Holden Mark A. , Coté Alexander S. , Ihli Johannes , Khalid Saba , Kulak Alexander , Walker Daniel , Tang Chiu , Duffy Dorothy M. , Kim Yi‐Yeoun , Meldrum Fiona C.
Published: May 2018

Biomineralisation processes invariably occur in the presence of multiple organic additives, which act in combination to give exceptional control over structures and properties. However, few synthetic studies have investigated the cooperative effects of soluble additives. This work addresses this challenge and focuses on the combined effects of amino acids and coloured dye molecules. The experiments demonstrate that strongly coloured calcite crystals only form in the presence of Brilliant Blue R (BBR) and four of the seventeen soluble amino acids, as compared with almost colourless crystals using the dye alone. The active amino acids are identified as those which themselves effectively occlude in calcite, suggesting a mechanism where they can act as chaperones for individual molecules or even aggregates of dyes molecules. These results provide new insight into crystal–additive interactions and suggest a novel strategy for generating materials with target properties.
Structure and Biocatalytic Scope of Coclaurine N‐Methyltransferase
Authors: Bennett Matthew R. , Thompson Mark L. , Shepherd Sarah A. , Dunstan Mark S. , Herbert Abigail J. , Smith Duncan R. M. , Cronin Victoria A. , Menon Binuraj R. K. , Levy Colin , Micklefield Jason
Published: May 2018

Benzylisoquinoline alkaloids (BIAs) are a structurally diverse family of plant secondary metabolites, which have been exploited to develop analgesics, antibiotics, antitumor agents, and other therapeutic agents. Biosynthesis of BIAs proceeds via a common pathway from tyrosine to (S)‐reticulene at which point the pathway diverges. Coclaurine N‐methyltransferase (CNMT) is a key enzyme in the pathway to (S)‐reticulene, installing the N‐methyl substituent that is essential for the bioactivity of many BIAs. In this paper, we describe the first crystal structure of CNMT which, along with mutagenesis studies, defines the enzymes active site architecture. The specificity of CNMT was also explored with a range of natural and synthetic substrates as well as co‐factor analogues. Knowledge from this study could be used to generate improved CNMT variants required to produce BIAs or synthetic derivatives.
Higher Acenes by On‐Surface Dehydrogenation: From Heptacene to Undecacene
Authors: Zuzak Rafal , Dorel Ruth , Kolmer Marek , Szymonski Marek , Godlewski Szymon , Echavarren Antonio M.
Published: May 2018

A unified approach to the synthesis of the series of higher acenes up to previously unreported undecacene has been developed through the on‐surface dehydrogenation of partially saturated precursors. These molecules could be converted into the parent acenes by both atomic manipulation with the tip of a scanning tunneling and atomic force microscope (STM/AFM) as well as by on‐surface annealing. The structure of the generated acenes has been visualized by high‐resolution non‐contact AFM imaging and the evolution of the transport gap with the increase of the number of fused benzene rings has been determined on the basis of scanning tunneling spectroscopy (STS) measurements.
Access to the Enantiopure Axially Chiral Cyclophane Isoplagiochin D through Atropo‐diastereoselective Heck Coupling
Authors: Meidlinger Daniel , Marx Lisa , Bordeianu Catalina , Choppin Sabine , Colobert Françoise , Speicher Andreas
Published: May 2018

Macrocyclization is typically the key step in the syntheses of cyclophane‐type natural products. Considering cyclophanes with axially chiral biaryl moieties, the control of atroposelectivity is essential with biological activity and is synthetically challenging. We report an atroposelective approach involving Heck cyclization, which for the first time enables the total synthesis of an enantiopure macrocyclic bis(bibenzyl), namely isoplagiochin D. An enantiopure sulfinyl auxiliary in the ortho position of a biaryl axis (still flexible) was used to induce an atropo‐diastereoselective Heck coupling (up to 98 % de). The traceless character of the sulfinyl auxiliary enables the introduction of a hydroxy group to give the target molecule with 98 % ee as well.
Experimental Realisation of Elusive Multiple‐Bonded Aluminium Compounds: A New Horizon in Aluminium Chemistry
Authors: Bag Prasenjit , Weetman Catherine , Inoue Shigeyoshi
Published: May 2018

The synthesis and isolation of stable main group compounds featuring multiple bonds has been of great interest for several decades. A plethora of such multiply bonded complexes have been obtained by using sterically demanding substituents that provide both kinetic and thermodynamic stability. Most of these compounds have unusual structural and electronic properties that challenge the classical concept of covalent multiple bonding. In contrast, analogous aluminium compounds are scarce in spite of its high natural abundance. The parent dialumene (Al2H2) has been calculated to be extremely unstable, thus making compounds containing Al multiple bonds a challenging synthetic target. This Review provides an overview of the recent advances in the cutting edge synthetic approaches and the careful ligand design used to obtain aluminium homo‐ and heterodiatomic multiply bonded complexes. In addition, the reactivity of these novel compounds towards various small molecules and reagents will be discussed herein.
Observation of a Metastable P‐Heterocyclic Radical by Muonium Addition to a 1,3‐Diphosphacyclobutane‐2,4‐diyl
Authors: Ito Shigekazu , Ueta Yasuhiro , Koshino Kota , Kojima Kenji M. , McKenzie Iain , Mikami Koichi
Published: May 2018

A 1,3‐diphosphacyclobutane‐2,4‐diyl contains a unique unsaturated cyclic unit, and the presence of radical‐type centers have been expected as a source of functionality. This study demonstrates that the P‐heterocyclic singlet biradical captures muonium (Mu=[μ+e−]), the light isotope of a hydrogen radical, to generate an observable P‐heterocyclic paramagnetic species. Investigation of a powder sample of 2,4‐bis(2,4,6‐tri‐t‐butylphenyl)‐1‐t‐butyl‐3‐benzyl‐1,3‐diphosphacyclobutane‐2,4‐diyl using muon (avoided) level‐crossing resonance (μLCR) spectroscopy revealed that muonium adds to the cyclic P2C2 unit. The muon hyperfine coupling constant (Aμ) indicated that the phosphorus atom bearing the t‐butyl group trapped muonium to provide a metastable P‐heterocyclic radical involving the ylidic MuP(<)=C moiety. The observed regioselective muonium addition correlates the canonical formula of 1,3‐diphosphacyclobutane‐2,4‐diyl.