bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparaison entre les étudiants de première et de seconde génération : engagement, rendement et persévérance
Authors: Mayer Denis
Published: August 2019

Cet article résume une recherche qui compare les étudiants de première et de seconde génération sur des facteurs d’engagement, de rendement et de persévérance en lien avec la langue du programme d’études à l’Université Laurentienne de Sudbury. La recherche a porté sur 514 étudiants en première année d’études inscrits dans des programmes de langues française ou anglaise dont 54 % étaient de la première génération, 91,4 % étaient citoyens canadiens et 83,5 % étaient de la race blanche; les femmes comptaient pour 73 % de l’échantillon.

Dans l’enquête, les étudiants de première génération étaient en moyenne plus âgés, en majorité des femmes, ils étaient inscrits à moins de cours et avaient fréquenté dans une plus forte proportion un collège avant d’arriver à l’université. Ils habitaient hors campus en plus grand nombre et, pour eux, l’intention de faire des études au doctorat était plus rare. L’instrumentNSSE2014 a fait voir neuf différences entre les étudiants de première et de seconde génération sur les questions/énoncés d’engagement. Les analyses sur la langue du programme d’études (français/anglais) ont montré des différences significatives pour 24 questions/énoncés. Les étudiants inscrits dans des programmes de langue française avaient un rendement supérieur quant aux crédits réussis. Toutefois, les analyses n’ont montré aucune différence entre les groupes quant à la persévérance dans les études, ce qui a conduit à mettre en doute la variable utilisée à cette fin.

Soixante-seize individus ont livré des remarques sur la qualité de leur expérience universitaire et avancé des recommandations pour l’établissement. Les commentaires furent rapportés en neuf catégories, quatre portant sur des aspects scolaires et cinq sur la vie étudiante. En gros, les remarques ont appuyé ou accentué les résultats des analyses quantitatives. La convergence d’opinions entre les groupes témoigne d’une appréciation plutôt comparable sur l’expérience éducative et le choix de l’établissement.

Somme toute, l’enquête a montré que la théorie de l’engagement parvient à relever des différences selon le statut de l’étudiant, mais davantage pour la langue du programme d’études, soit le français ou l’anglais. Les étudiants de première et de seconde génération qui étudiaient en français étaient plus engagés que les autres sur un nombre de variables de l’outilNSSE.
Albert Sangrà: «La apuesta de las organizaciones, universitarias o no, por el e-learning debe ser estratégica»
Authors: Gomis Joan Miquel
Published: August 2019

El profesor de la UOC Albert Sangrà está considerado uno de los expertos internacionales más destacados en el campo del uso de las tecnologías de la información y la comunicación en el ámbito de la educación y la formación. En esta entrevista reflexiona sobre los aspectos clave del e-learning, como son su base conceptual, sus modalidades o su influencia en las universidades presenciales tradicionales. Albert Sangrà aborda también cuestiones de actualidad en este ámbito, como el desarrollo de los Massive Open Online Course (MOOC), el trabajo y evaluación de las competencias en entornos virtuales y la aplicación del e-learning en la empresa, así como la colaboración entre empresa y universidad. La principal conclusión de la entrevista es que las instituciones, universitarias o no, que apuesten por el e-learning, lo deben hacer estratégicamente. Asimismo, tienen que entender que el e-learning va más allá del desarrollo de contenidos y que por lo tanto requiere de una metodología docente específica planificada a largo plazo. Además, considera que, en este entorno, empresas y universidades están condenadas a entenderse, a pesar de que en los últimos tiempos se hayan distanciado.
El bagaje competencial de los graduados en ADE, a debate
Authors: Fitó Bertran Àngels
Published: August 2019

Este artículo se basa en un estudio realizado a partir de encuestas realizadas a estudiantes, graduados y empresarios sobre la vigencia, una década después, de las competencias transversales incluidas en los documentos que sirvieron de base para el diseño de las nuevas titulaciones integradas en el EEES. Se realizaron además entrevistas en profundidad a cuatro directores generales de empresas responsables de selección de personal vinculadas al área de administración y dirección de empresas. Una de las principales conclusiones obtenida s refleja el consenso absoluto al considerar la evaluación de competencias transversales como la base de los procesos de selección. A su vez, los expertos se ponen de acuedo también al considerar la preponderancia del trabajo en equipo, seguido de las competencias para desarrollar tareas en entornos internacionales. También muestran escepticismo ante el papel que ejercen las universidades en el desarrollo de esta habilidad y finalmente se muestran especialmente receptivos a la formación en línea, no sólo por las ventajas en términos de accesibilidad y compatibilidad con la actividad profesional, sino porque incorpora el desarrollo de habilidades como la autonomía, la capacidad de análisis crítico de la información, de organización del trabajo y de gestión del tiempo, todas ellas vitales en los tiempos actuales.
Tus sueños y la teoría de la probabilidad
Authors: Liviano Solís Daniel
Published: August 2019

En este artículo se analiza desde un punto de vista estadístico y probabilístico el mecanismo y la interpretación de los juegos de azar consistentes en la extracción de bolas de una urna. Para ello, se introducen los conceptos de variable aleatoria, espacio muestral, esperanza matemática y valor esperado. Para ilustrar estos conceptos se desarrolla un sencillo ejemplo, en el cual se compara el valor esperado del juego con lo que cuesta jugar. Estos conceptos teóricos se aplican, seguidamente, a un ejemplo real: el sorteo de Navidad de Loterías y Apuestas del Estado. Mediante el análisis estadístico de los diferentes premios que reparte y su probabilidad asociada, se llega a la conclusión de que el valor esperado del premio es aproximadamente de dos tercios. Esto significa que, por cada euro que se invierte regularmente, sólo se recuperan a largo plazo 0,66 €. Una simulación realizada con estos datos constata gráficamente este resultado y muestra también que el hecho de repartir el gasto en el juego entre más números jugados aumenta la probabilidad de ampliar el número de premios ganados, aunque el valor asintótico siga siendo de dos tercios.
Organizaciones, redes sociales y gestión del conocimiento
Authors: Canals Agustí
Published: August 2019

Las redes sociales juegan un papel muy relevante como sustrato, sobre el que se producen la mayoría de los procesos relacionados con la transmisión de información y la generación y transferencia de conocimiento. La gestión del conocimiento, que tiene como una de sus funciones lograr optimizar estos procesos en las organizaciones, debe tener en cuenta esta función esencial de las redes sociales. En este artículo describimos algunos de los mecanismos concretos por los que la estructura de las redes sociales influye en la efectividad de la transmisión de información y también de la creación y transferencia de conocimiento. A partir de esto, se pueden deducir algunas consideraciones sobre las características de las redes sociales que son más indicadas en cada caso para la consecución de los objetivos de la organización. La gestión del conocimiento debe saber utilizar las redes existentes y, si es posible, conseguir que estas redes adopten la estructura más adecuada.
Rethinking the usage and experience of clustering markers in web mapping
Authors: Fürhoff Loïc
Published: August 2019

Although the notion of ‘too many markers’ have been mentioned in several research, in practice, displaying hundreds of Points of Interests (POI) on a web map in two dimensions with an acceptable usability remains a real challenge. Web practitioners often make an excessive use of clustering aggregation to overcome performance bottlenecks without successfully resolving issues of perceived performance. This paper tries to bring a broad awareness by identifying sample issues which describe a general reality of clustering, and provide a pragmatic survey of potential technologies optimisations. At the end, we discuss the usage of technologies and the lack of documented client-server workflows, along with the need to enlarge our vision of the various clutter reduction methods.
Complex Demonstratives
Authors: King Jeffrey C.
Published: August 2019

Since the late 1970s, the orthodox view of complex 'that' phrases (e.g., 'that woman eating a granola bar') has been that they are contextually sensitive devices of direct reference. In Complex Demonstratives, Jeffrey King challenges that orthodoxy, showing that quantificational accounts not only are as effective as direct reference accounts but also handle a wider range of data.

After providing arguments against direct reference accounts of 'that' phrases and developing a quantificational theory of them, King looks at the interaction of 'that' phrases with modal operators, negation, and verbs of propositional attitude. He argues for evidence of scope interaction between 'that' phrases and other scoped elements. King also addresses semantic properties of 'that' and other determiners, and the possibility of extending the semantics of 'that' phrases to 'that' as a syntactically simple demonstrative. Finally, he argues against what he calls ambiguity approaches, theories that hold that the various uses of 'that' phrases cannot be treated by a single semantical theory.

Bradford Books imprint
English-Japanese, Japanese-English Dictionary of Computer and Data-Processing Terms
Authors: Ferber Gene
Published: August 2019

Winner, 1989, category of Computer Science, Professional/Scholarly Publishing Annual Awards Competition presented by the Association of American Publishers, Inc. With 10,000 entries, this dictionary is the most complete of its kind. It is a major contribution to more accurate sharing of scientific and technological information. The dictionary is unique in providing a romanized transcription for each of the 10,000 Japanese terms. It promotes clear oral communication, whether one is using purely Japanese words or terms that have been borrowed from English but are pronounced somewhat differently by the Japanese. Professional translators of Japanese, English-speaking engineers and computer and dataprocessing professionals dealing with Japanese products or companies, marketing executives, and journalists are among those who will find this dictionary indispensable for such uses as translating an instruction manual, composing a telex message, ordering materials and parts, looking up a word during a face to face conversation, or interviewing executives in a technical field. The Japanese English section lists the romanized Japanese words (Romaji) according to the Roman rather than the Japanese alphabet, thus simplifying reference by Western speakers of Japanese as well as by native speakers of Japanese who are familiar with both Roman script and alphabetical order. The dictionary also aids Western recognition and reproduction of katakana characters (Japanese characters used to represent the sounds of borrowed foreign words) by providing the exact romanized transcriptions of words borrowed from English and expressed in katakana form instead of keeping such words in their original forms. The word "computer" for instance, may be translated indigenously as "keisanki," but the borrowed English "konpyuta" is also widely used. The dictionary gives the romanizations of both, to facilitate verbal communication; it also gives, for readers of Japanese, the ideogrammic representations of both words.
Money, Interest, and Policy
Authors: Benassy Jean-Pascal
Published: August 2019

An important recent advance in macroeconomics is the development of dynamic stochastic general equilibrium (DSGE) macromodels. The use of DSGE models to study monetary policy, however, has led to paradoxical and puzzling results on a number of central monetary issues including price determinacy and liquidity effects. In Money, Interest, and Policy, Jean-Pascal Bénassy argues that moving from the standard DSGE models – which he calls "Ricardian" because they have the famous "Ricardian equivalence" property–to another, "non-Ricardian" model would resolve many of these issues. A Ricardian model represents a household as a homogeneous family of infinitely lived individuals, and Bénassy demonstrates that a single modification–the assumption that new agents are born over time (which makes the model non-Ricardian)–can bridge the current gap between monetary intuitions and facts, on one hand, and rigorous modeling, on the other.

After comparing Ricardian and non-Ricardian models, Bénassy introduces a model that synthesizes the two approaches, incorporating both infinite lives and the birth of new agents. Using this model, he considers a number of issues in monetary policy, including liquidity effects, interest rate rules and price determinacy, global determinacy, the Taylor principle, and the fiscal theory of the price level. Finally, using a simple overlapping generations model, he analyzes optimal monetary and fiscal policies, with a special emphasis on optimal interest rate rules.
Invented Edens
Authors: Kargon Robert H. , Molella Arthur P.
Published: August 2019

Tracing the design of “techno-cities” that blend the technological and the pastoral.

Industrialization created cities of Dickensian squalor that were crowded, smoky, dirty, and disease-ridden. By the beginning of the twentieth century, urban visionaries were looking for ways to improve both living and working conditions in industrial cities. In Invented Edens, Robert Kargon and Arthur Molella trace the arc of one form of urban design, which they term the techno-city: a planned city developed in conjunction with large industrial or technological enterprises, blending the technological and the pastoral, the mill town and the garden city. Techno-cities of the twentieth century range from factory towns in Mussolini's Italy to the Disney creation of Celebration, Florida.

Kargon and Molella show that the techno-city represents an experiment in integrating modern technology into the world of ideal life. Techno-cities mirror society's understanding of current technologies, and at the same time seek to regain the lost virtues of the edenic pre-industrial village. The idea of the techno-city transcended ideologies, crossed national borders, and spanned the entire twentieth century. Kargon and Molella map the concept through a series of exemplars. These include Norris, Tennessee, home to the Tennessee Valley Authority; Torviscosa, Italy, built by Italy's Fascist government to accommodate synthetic textile manufacturing (and featured in an early short by Michelangelo Antonioni); Ciudad Guayana, Venezuela, planned by a team from MIT and Harvard; and, finally, Disney's Celebration—perhaps the ultimate techno-city, a fantasy city reflecting an era in which virtual experiences are rapidly replacing actual ones.
Metabolomic analysis reveals the mechanism of aluminum cytotoxicity in HT-29 cells
Authors: Yu Leilei , Wu Jiangping , Zhai Qixiao , Tian Fengwei , Zhao Jianxin , Zhang Hao , Chen Wei
Published: August 2019

Background

Aluminum (Al) is toxic to animals and humans. The most common sources of human exposure to Al are food and beverages. The intestinal epithelium is the first barrier against Al-induced toxicity. In this study, HT-29, a human colon cancer cell line, was selected as an in vitro model to evaluate the Al-induced alteration in metabolomic profiles and explore the possible mechanisms of Al toxicity.

Methods

MTT assay was performed to determine the half-maximal inhibitory concentration of Al ions. Liquid chromatography-mass spectrometry (LC-MS) was used for metabolomic analysis, and its results were further confirmed using quantitative reverse transcription polymerase chain reaction (RT-qPCR) of nine selected genes.

Results

Al inhibited the growth of the HT-29 cells, and its half-maximal dose for the inhibition of cell proliferation was found to be four mM. This dose was selected for further metabolomic analysis, which revealed that 81 metabolites, such glutathione (GSH), phosphatidylcholines, phosphatidylethanolamines, and creatine, and 17 metabolic pathways, such as the tricarboxylic acid cycle, pyruvate metabolism, and GSH metabolism, were significantly altered after Al exposure. The RT-qPCR results further confirmed these findings.

Conclusion

The metabolomics and RT-qPCR results indicate that the mechanisms of Al-induced cytotoxicity in HT-29 cells include cellular apoptosis, oxidative stress, and alteration of lipid, energy, and amino acid metabolism.
Marked variations in gut microbiota and some innate immune responses of fresh water crayfish, marron (Cherax cainii, Austin 2002) fed dietary supplementation of Clostridium butyricum
Authors: Foysal Md Javed , Nguyen Thi Thu Thuy , Chaklader Md Reaz , Siddik Muhammad A.B. , Tay Chin-Yen , Fotedar Ravi , Gupta Sanjay Kumar
Published: August 2019

This study aimed to investigate the effects of Clostridium butyricum as a dietary probiotic supplement in fishmeal based diet on growth, gut microbiota and immune performance of marron (Cherax cainii). Marron were randomly distributed into two different treatment groups, control and probiotic fed group. After 42 days of feeding trial, the results revealed a significant (P < 0.05) increase in growth due to increase in number of moults in marron fed probiotics. The probiotic diet also significantly enhanced the total haemocyte counts (THC), lysozyme activity in the haemolymph and protein content of the tail muscle in marron. Compared to control, the 16S rRNA sequences data demonstrated an enrichment of bacterial diversity in the probiotic fed marron where significant increase of Clostridium abundance was observed. The abundance for crayfish pathogen Vibrio and Aeromonas were found to be significantly reduced post feeding with probiotic diet. Predicted metabolic pathway revealed an increased activity for the metabolism and absorption of carbohydrate, degradation of amino acid, fatty acid and toxic compounds, and biosynthesis of secondary metabolites. C. butyricum supplementation also significantly modulated the expression level of immune-responsive genes of marron post challenged with Vibrio mimicus. The overall results suggest that C. butyricum could be used as dietary probiotic supplement in marron aquaculture.
Simultaneous Profiling of Gene Expression and Chromatin Accessibility in Single Cells
Authors: Reyes Miguel , Billman Kianna , Hacohen Nir , Blainey Paul C.
Published: August 2019

Profiling multiple omic layers in a single cell enables the discovery and analysis of biological phenomena that are not apparent from analysis of mono‐omic data. While methods for multiomic profiling have been reported, their adoption has been limited due to high cost and complex workflows. Here, a simple method for joint profiling of gene expression and chromatin accessibility in tens to hundreds of single cells is presented. Assessed herein is the quality of resulting single cell ATAC‐ and RNA‐seq data across three cell types, examining the link between accessibility and expression at the CD3G and FTH1 loci in human primary T cells and monocytes, and comparing the accuracy of clustering solutions for mono‐omic and combined data. The new method allows biological laboratories to perform simultaneous profiling of gene expression and chromatin accessibility using standard reagents and instrumentation. This technique, in conjunction with other advances in multiomic profiling, will enable highly resolved cell state classification and more specific mechanistic hypothesis generation than is possible with mono‐omic analysis.
Precise Molecular Engineering of Photosensitizers with Aggregation‐Induced Emission over 800 nm for Photodynamic Therapy
Authors: Wu Wenbo , Mao Duo , Xu Shidang , Panahandeh‐Fard Majid , Duan Yukun , Hu Fang , Kong Deling , Liu Bin
Published: August 2019

Owing to efficient singlet oxygen (1O2) generation in aggregate state, photosensitizers (PSs) with aggregation‐induced emission (AIE) have attracted much research interests in photodynamic therapy (PDT). In addition to high 1O2 generation efficiency, strong molar absorption in long‐wavelength range and near‐infrared (NIR) emission are also highly desirable, but difficult to achieve for AIE PSs since the twisted structures in AIE moieties usually lead to absorption and emission in short‐wavelength range. In this contribution, through acceptor engineering, a new AIE PS of TBT is designed to show aggregation‐induced NIR emission centered at 810 nm, broad absorption in the range between 300 and 700 nm with a large molar absorption coefficient and a high 1O2 generation efficiency under white light irradiation. Further, donor engineering by attaching two branched flexible chains to TBT yielded TBTC8, which circumvented the strong intermolecular interactions of TBT in nanoparticles (NPs), yielding TBTC8 NPs with optimized overall performance in 1O2 generation, absorption, and emission. Subsequent PDT results in both in vitro and in vivo studies indicate that TBTC8 NPs are promising candidates in practical application.
The Promise and Challenge of Phosphorus‐Based Composites as Anode Materials for Potassium‐Ion Batteries
Authors: Wu Ying , Huang Hai‐Bo , Feng Yuezhan , Wu Zhong‐Shuai , Yu Yan
Published: August 2019

Potassium‐ion batteries (KIBs) are a core energy storage device that can meet the need for scalable and affordable stationary applications because they use low‐cost and earth‐abundant potassium. In addition, KIB shares a similar storage mechanism with current Li‐ion batteries. As the key to optimizing a battery's performance, the development of high‐performance electrode materials helps to increase the feasibility of KIB technology. In this sense, phosphorus‐based materials (i.e., phosphorus and metal phosphide) with high theoretical capacity and low redox potential tick all the right boxes as a material of choice. A rapid glimpse at recent studies on phosphorus‐based anode materials for advanced KIBs is provided, covering the synthetic methods, reaction mechanisms, electrochemical properties, and performances. In addition, several promising strategies are highlighted to address the imminent challenges faced by phosphorus‐based anode materials, hoping to cast an insightful outlook for possible future direction in this field.
Targeted Therapy for Interfacial Engineering Toward Stable and Efficient Perovskite Solar Cells
Authors: Wang Shuhui , Chen Haiyang , Zhang Jiandong , Xu Guiying , Chen Weijie , Xue Rongming , Zhang Moyao , Li Yaowen , Li Yongfang
Published: August 2019

The poor long‐term stability of organic–inorganic hybrid halide perovskite solar cells (pero‐SCs) remains a big challenge for their commercialization. Although strategies such as encapsulation, doping, and passivation have been reported, there remains a lack of understanding of the water resistance and thermal stability of pero‐SCs. A fullerene derivative, [6,6]‐phenyl‐C61‐butyric acid‐N,N‐dimethyl‐3‐(2‐thienyl)propanam ester (PCBB‐S‐N) containing a functional sulfur atom and C60,is synthesized and employed as electron transporting layer (ETL)/intermediary layer to targetedly heal the multitype defects in pero‐SCs or assist the growth of ETL, such as [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM), in planarp‐i‐npero‐SCs. The repaired pero‐SCs can not only dramatically improve their power conversion efficiencies, but also address stability issues under moisture and high temperature. The corresponding mechanism of PCBB‐S‐N with targeted therapy effect in a device is systematically investigated by both experiments and theoretical calculation. This work demonstrates that the proposed fullerene derivative with finely tuned chemical structure can be a promising ETL candidate or intermediary to approach stable and efficient planarp‐i‐npero‐SCs.
Layered Structure Causes Bulk NiFe Layered Double Hydroxide Unstable in Alkaline Oxygen Evolution Reaction
Authors: Chen Rong , Hung Sung‐Fu , Zhou Daojin , Gao Jiajian , Yang Cangjie , Tao Huabing , Yang Hong Bin , Zhang Liping , Zhang Lulu , Xiong Qihua , Chen Hao Ming , Liu Bin
Published: August 2019

NiFe‐based layered double hydroxides (LDHs) are among the most efficient oxygen evolution reaction (OER) catalysts in alkaline medium, but their long‐term OER stabilities are questionable. In this work, it is demonstrated that the layered structure makes bulk NiFe LDH intrinsically not stable in OER and the deactivation mechanism of NiFe LDH in OER is further revealed. Both operando electrochemical and structural characterizations show that the interlayer basal plane in bulk NiFe LDH contributes to the OER activity, and the slow diffusion of proton acceptors (e.g., OH−) within the NiFe LDH interlayers during OER causes dissolution of NiFe LDH and therefore decrease in OER activity with time. To improve diffusion of proton acceptors, it is proposed to delaminate NiFe LDH into atomically thin nanosheets, which is able to effectively improve OER stability of NiFe LDH especially at industrial operating conditions such as elevated operating temperatures (e.g., at 80 °C) and large current densities (e.g., at 500 mA cm−2).
Severe lung disease characterized by lymphocytic bronchiolitis, alveolar ductitis, and emphysema (BADE) in industrial machine‐manufacturing workers
Authors: Cummings Kristin J. , Stanton Marcia L. , Nett Randall J. , Segal Leopoldo N. , Kreiss Kathleen , Abraham Jerrold L. , Colby Thomas V. , Franko Angela D. , Green Francis H.Y. , Sanyal Soma , Tallaksen Robert J. , Wendland Douglas , Bachelder Vance D. , Boylstein Randy J. , Park Ju‐Hyeong , Cox‐Ganser Jean M. , Virji M. Abbas , Crawford Judith A. , Green Brett James , LeBouf Ryan F. , Blaser Martin J. , Weissman David N.
Published: August 2019

Background

A cluster of severe lung disease occurred at a manufacturing facility making industrial machines. We aimed to describe disease features and workplace exposures.

Methods

Clinical, functional, radiologic, and histopathologic features were characterized. Airborne concentrations of thoracic aerosol, metalworking fluid, endotoxin, metals, and volatile organic compounds were measured. Facility airflow was assessed using tracer gas. Process fluids were examined using culture, polymerase chain reaction, and 16S ribosomal RNA sequencing.

Results

Five previously healthy male never‐smokers, ages 27 to 50, developed chest symptoms from 1995 to 2012 while working in the facility's production areas. Patients had an insidious onset of cough, wheeze, and exertional dyspnea; airflow obstruction (mean FEV1 = 44% predicted) and reduced diffusing capacity (mean = 53% predicted); and radiologic centrilobular emphysema. Lung tissue demonstrated a unique pattern of bronchiolitis and alveolar ductitis with B‐cell follicles lacking germinal centers, and significant emphysema for never‐smokers. All had chronic dyspnea, three had a progressive functional decline, and one underwent lung transplantation. Patients reported no unusual nonoccupational exposures. No cases were identified among nonproduction workers or in the community. Endotoxin concentrations were elevated in two air samples; otherwise, exposures were below occupational limits. Air flowed from areas where machining occurred to other production areas. Metalworking fluid primarily grew Pseudomonas pseudoalcaligenes and lacked mycobacterial DNA, but 16S analysis revealed more complex bacterial communities.

Conclusion

This cluster indicates a previously unrecognized occupational lung disease of yet uncertain etiology that should be considered in manufacturing workers (particularly never‐smokers) with airflow obstruction and centrilobular emphysema. Investigation of additional cases in other settings could clarify the cause and guide prevention.
Chemical Patterning in Single Crystals of Metal–Organic Frameworks by [2+2] Cycloaddition Reaction
Authors: Park In‐Hyeok , Lee Eunji , Lee Shim Sung , Vittal Jagadese J.
Published: August 2019

Conventional chemical patterning involves films of polymeric materials. Herein, we demonstrate that the presence or absence of guest solvents in the crystal voids modulates the patterning of the cyclobutane rings in highly strained metal–organic frameworks (MOFs) under UV light. The olefin pairs of the spacer ligands, which resemble a ladder‐like structure, in the MOF, undergo a [2+2] cycloaddition reaction in a single‐crystal‐to‐single‐crystal manner. For instance, a partial photoreaction in the MOFs in the absence of a guest solvent as well as with dimethylacetamide in the voids generated two different patterns of the cyclobutane rings. Surprisingly, the MOF with the lattice dimethylformamide undergoes 100 % photoreaction, but the photoproduct contains broken chains. Such chemical patterning at the molecular level represents a next step in crystal engineering.
Catalytic Living Ring Opening Metathesis Polymerisation: The Importance of Ring Strain in Chain Transfer Agents
Authors: Liu Peng , Yasir Mohammad , Kilbinger Andreas F. M.
Published: August 2019

A recently developed catalytic living ring opening metathesis polymerisation (ROMP) was investigated using a series of reversible chain transfer agents (CTA) carrying either cyclopentene or cyclohexene rings, differing only in ring strain. All cyclopentene derivatives examined showed significantly faster reaction rates than the corresponding cyclohexene derivatives. This resulted in lower molecular weight dispersities and better control of the molecular weight for the cyclopentene compared to the cyclohexene CTAs. Both Grubbs’ second and third generation catalysts could be employed in catalytic living ROMP using cyclopentene CTA derivatives. The kinetics of different CTAs were studied, block copolymers were synthesised and residual ruthenium quantified by ICP‐OES. All polymers were fully characterised by NMR, GPC and MALDI‐ToF mass spectrometry. The new cyclopentene CTAs are readily synthesised in a few straightforward steps and provide faster reaction kinetics than all previously reported reversible CTAs.
A Stark Contrast to Modern Earth: Phosphate Mineral Transformation and Nucleoside Phosphorylation in an Iron‐ and Cyanide‐Rich Early Earth Scenario
Authors: Burcar Bradley , Castañeda Alma , Lago Jennifer , Daniel Mischael , Pasek Matthew A. , Hud Nicholas V. , Orlando Thomas M. , Menor‐Salván César
Published: August 2019

Organophosphates were likely an important class of prebiotic molecules. However, their presence on the early Earth is strongly debated because the low availability of phosphate, which is generally assumed to have been sequestered in insoluble calcium and iron minerals, is widely viewed as a major barrier to organophosphate generation. Herein, we demonstrate that cyanide (an essential prebiotic precursor) and urea‐based solvents could promote nucleoside phosphorylation by transforming insoluble phosphate minerals in a “warm little pond” scenario into more soluble and reactive species. Our results suggest that cyanide and its derivatives (metal cyanide complexes, urea, ammonium formate, and formamide) were key reagents for the participation of phosphorus in chemical evolution. These results allow us to propose a holistic scenario in which an evaporitic environment could concentrate abiotically formed organics and transform the underlying minerals, allowing significant organic phosphorylation under plausible prebiotic conditions.
Defect‐Rich Adhesive Nanozymes as Efficient Antibiotics for Enhanced Bacterial Inhibition
Authors: Cao Fangfang , Zhang Lu , Wang Huan , You Yawen , Wang Ying , Gao Nan , Ren Jinsong , Qu Xiaogang
Published: August 2019

Nanozymes have emerged as a new generation of antibiotics with exciting broad‐spectrum antimicrobial properties and negligible biotoxicities. However, their antibacterial efficacies are unsatisfactory due to their inability to trap bacteria and their low catalytic activity. Herein, we report nanozymes with rough surfaces and defect‐rich active edges. The rough surface increases bacterial adhesion and the defect‐rich edges exhibit higher intrinsic peroxidase‐like activity compared to pristine nanozymes due to their lower adsorption energies of H2O2 and desorption energy of OH*, as well as the larger exothermic process for the whole reaction. This was demonstrated using drug‐resistant Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus in vitro and in vivo. This strategy can be used to engineer nanozymes with enhanced antibacterial function and will pave a new way for the development of alternative antibiotics.
Atroposelective Phosphoric Acid Catalyzed Three‐Component Cascade Reaction: Enantioselective Synthesis of Axially Chiral N‐Arylindoles
Authors: Wang Lei , Zhong Jialing , Lin Xufeng
Published: August 2019

An efficient organocatalytic atroposelective three‐component cascade reaction of 2,3‐diketoesters, aromatic amines, and 1,3‐cyclohexanediones has been developed for the highly enantioselective synthesis of axially chiral N‐arylindoles. The success of this method derives from the use of a newly developed second‐generation chiral spirocyclic phosphoric acid as the catalyst. In addition, this protocol was extended to the synthesis of an axially chiral monophosphorus ligand.
Elaborating Complex Heteroaryl‐Containing Cycles via Enantioselective Palladium‐Catalyzed Cycloadditions
Authors: Trost Barry M. , Jiao Zhiwei , Hung Chao‐I. (Joey)
Published: August 2019

A general method for asymmetric synthesis of heteroaryl‐containing cycles via palladium‐catalyzed cyclization is reported. Most classes of nitrogen‐containing aromatics, including pyridines, quinolines, pyrimidines, various azoles and the derivatives of nucleobases are compatible substrates, offering various heteroaryl‐substituted cyclopentane, pyrrolidine, furanidine and bicyclo[4.3.1]decadiene derivatives with good to excellent enantioselectivity and diastereoselectivity.
Preparation of Polyfunctional Biaryl Derivatives by Cyclolanthanation of 2‐Bromobiaryls and Heterocyclic Analogues Using nBu2LaCl⋅4 LiCl
Authors: Wei Baosheng , Zhang Dongchao , Chen Yi‐Hung , Lei Aiwen , Knochel Paul
Published: August 2019

Various aryl‐ and heteroaryl‐substituted 2‐bromobiaryls are converted to cyclometalated lanthanum intermediates by reaction with nBu2LaCl⋅4 LiCl. These resulting lanthanum heterocycles are key intermediates for the facile preparation of functionalized 2,2′‐diiodobiaryls, silafluorenes, fluoren‐9‐ones, phenanthrenes, and their related heterocyclic analogues. X‐ray absorption fine structure (XAFS) spectroscopy was used to rationalize the proposed structures of the involved organolanthanum species.
Acyl‐Directed ortho‐Borylation of Anilines and C7 Borylation of Indoles using just BBr3
Authors: Iqbal Saqib A. , Cid Jessica , Procter Richard J. , Uzelac Marina , Yuan Kang , Ingleson Michael J.
Published: August 2019

Indoles are privileged heterocycles found in many biologically active pharmaceuticals and natural products. However, the selective functionalization of the benzenoid moiety in indoles in preference to the more reactive pyrrolic unit is a significant challenge. Herein we report that N‐acyl directing groups enable the C7‐selective C−H borylation of indoles using just BBr3. This transformation shows some functional‐group tolerance and notably proceeds with C6 substituted indoles. The directing group can be readily removed in situ and the products isolated as the pinacol boronate esters. Acyl‐directed electrophilic borylation can be extended to carbazoles and anilines with excellent ortho selectivity. 4‐amino‐indoles are amenable to this process, with acyl group installation and directed electrophilic C−H borylation enabling selective formation of C5‐BPin‐indoles.
Luminescent mononuclear and dinuclear cycloplatinated (II) complexes comprising azide and phosphine ancillary ligands
Authors: Nikahd Sahebeh , Babadi Aghakhanpour Reza , Nabavizadeh S. Masoud , Niroomand Hosseini Fatemeh , Hoseini S. Jafar , Pfitzner Arno , Samandar Sangari Mozhgan
Published: August 2019

A new series of cycloplatinated (II) complexes with general formulas of [Pt (bhq)(N3)(P)] [bhq = deprotonated 7,8‐benzo[h]quinoline, P = triphenyl phosphine (PPh3) and methyldiphenyl phosphine], [Pt (bhq)(P^P)]N3 [P^P = 1,1‐bis (diphenylphosphino)methane (dppm) and 1,2‐bis (diphenylphosphino)ethane] and [Pt2(bhq)2(μ‐P^P)(N3)2] [P^P = dppm and 1,2‐bis (diphenylphosphino)acetylene] is reported in this investigation. A combination of azide (N3−) and phosphine (monodentate and bidentate) was used as ancillary ligands to study their influences on the chromophoric cyclometalated ligand. All complexes were characterized by nuclear magnetic resonance spectroscopy. To confirm the presence of the N3− ligand directly connected to the platinum center, complex [Pt (bhq)(N3)(PPh3)] was further characterized by single‐crystal X‐ray crystallography. The photophysical properties of the new products were studied by UV–Vis spectroscopy in CH2Cl2 and photoluminescence spectroscopy in solid state (298 or 77 K) and in solution (77 K). Using density functional theory calculations, it was proved that, in addition to intraligand charge‐transfer (ILCT) and metal‐to‐ligand charge‐transfer (MLCT) transitions, the L′LCT (L′ = N3, L = C^N) electronic transition has a remarkable contribution in low energy bands of the absorption spectra (for complexes [Pt (bhq)(N3)(P)] and [Pt2(bhq)2(μ‐P^P)(N3)2]). It is indicative of the determining role of the N3− ligand in electronic transitions of these complexes, specifically in the low energy region. In this regard, the photoluminescence studies indicated that the emissions in such complexes originate from a mixed 3ILCT/3MLCT (intramolecular) and also from aggregations (intermolecular).
Feed‐in‐tariffs and the politics of renewable energy in Indonesia and the Philippines
Authors: Guild James
Published: August 2019

The ability of Southeast Asia's largest economies to develop renewable energy sectors is important for the reduction of carbon emissions. A popular policy tool for jump‐starting growth in renewables is feed‐in‐tariffs (FITs), whereby the government pays a long‐term and mutually agreed rate to independent power producers to develop renewable energies such as solar, biomass, wind, and hydropower. Indonesia and the Philippines have both adopted FITs in recent years, and the result has been a strong growth of renewable energy in the Philippines, but not in Indonesia. This difference can be partly explained by variances in policy design and political economic conditions that have impacted policy success. The Philippines enacted a FIT scheme that reflected several best practices in policy design. The political economic conditions of energy markets in the Philippines were also initially more favourable. The variance in these components helps to explain the divergent results of their respective FIT systems.
Aggregation‐Induced Emission Properties of Copper Iodide Clusters
Authors: Utrera‐Melero Raquel , Mevellec Jean‐Yves , Gautier Nicolas , Stephant Nicolas , Massuyeau Florian , Perruchas Sandrine
Published: August 2019

The aggregation‐induced emission (AIE) properties of two different copper iodide clusters have been studied. These two [Cu4I4L4] clusters differ by their coordinated phosphine ligand and the luminescent mechanochromic properties are only displayed by one of them. The two clusters are AIE‐active luminophors that exhibit an intense emission in the visible region upon aggregation. The formed particles present luminescent thermochromism comparable to that of the bulk compounds. The observed AIE properties can be attributed to suppression of nonradiative relaxation of the excited states in a more rigid state, in relation to the large structural relaxation of the excited triplet state. The differences observed in the AIE properties of the two clusters can be related to the different ligands. A correlation between the luminescence mechanochromic properties and the AIE effect is not straightforward, but the formation of “soft” molecular solids is a common characteristic that can explain the photoactive properties of these compounds.
Potential for biojet production from different biomass feedstocks and consolidated technological routes: a georeferencing and spatial analysis in Brazil
Authors: Carvalho Francielle , da Silva Fabio T. F. , Szklo Alexandre , Portugal‐Pereira Joana
Published: August 2019

This paper assesses the biojet fuel production potential in Brazil. It evaluates feedstock availability by applying a georeferencing analysis, and determines the cost‐effectiveness and greenhouse gas (GHG) emissions of selected production routes throughout their entire life cycle. This study identifies and locates Brazilian hotspots in terms of bioenergy availability and proximity to the main sites of fuel consumption and handling in the country. Findings show that the biomass availability for each crop in the hotspots would be sufficient to feed the biojet conversion plants proposed in this study. The biojet production potential in the hotspots would represent 48% of the country's jet fuel consumption in 2014, allowing the current certificated 50% blend with conventional fuel. The major biomass hotspots are close to airport and fuel logistic basis. However, even with a US$ 200.tCO–1
2 tax, hydroprocessed esters and fatty acids (HEFA) biojet is far from being competitive with petroleum‐based jet fuel, whereas the Fischer–Tropsch synthetic paraffinic kerosene (FT‐SPK) route may produce a competitive biojet. One possible pathway to incentivize biojet fuel production in Brazil would be, first, to implement carbon taxes that would allow the development of smaller plants. Then, with technological learning and larger production scales, it would be possible to reduce or even eliminate the carbon taxes. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.
Scaffoldless tissue‐engineered cartilage for studying transforming growth factor beta‐mediated cartilage formation
Authors: Chavez Robert D. , Serra Rosa
Published: August 2019

Reduced transforming growth factor beta (TGF‐β) signaling is associated with osteoarthritis (OA). TGF‐β is thought to act as a chondroprotective agent and provide anabolic cues to cartilage, thus acting as an OA suppressor in young, healthy cartilage. A potential approach for treating OA is to identify the factors that act downstream of TGF‐β's anabolic pathway and target those factors to promote cartilage regeneration or repair. The aims of the present study were to (a) develop a scaffoldless tissue‐engineered cartilage model with reduced TGF‐β signaling and disrupted cartilage formation and (b) validate the system for identifying the downstream effectors of TGF‐β that promote cartilage formation. Sox9 was used to validate the model because Sox9 is known to promote cartilage formation and TGF‐β regulates Sox9 activity. Primary bovine articular chondrocytes were grown in Transwell supports to form cartilage tissues. An Alk5/TGF‐β type I receptor inhibitor, SB431542, was used to attenuate TGF‐β signaling, and an adenovirus encoding FLAG‐Sox9 was used to drive the expression of Sox9 in the in vitro‐generated cartilage. SB431542‐treated tissues exhibited reduced cartilage formation including reduced thicknesses and reduced proteoglycan staining compared with control tissue. Expression of FLAG‐Sox9 in SB431542‐treated cartilage allowed the formation of cartilage despite antagonism of the TGF‐β receptor. In summary, we developed a three‐dimensional in vitro cartilage model with attenuated TGF‐β signaling. Sox9 was used to validate the model for identification of anabolic agents that counteract loss of TGF‐β signaling. This model has the potential to identify additional anabolic factors that could be used to repair or regenerate damaged cartilage.
Refinement of risk stratification for childhood rhabdomyosarcoma using FOXO1 fusion status in addition to established clinical outcome predictors: A report from the Children's Oncology Group
Authors: Hibbitts Emily , Chi Yueh‐Yun , Hawkins Douglas S. , Barr Frederic G. , Bradley Julie A. , Dasgupta Roshni , Meyer William H. , Rodeberg David A. , Rudzinski Erin R. , Spunt Sheri L. , Skapek Stephen X. , Wolden Suzanne L. , Arndt Carola A. S.
Published: August 2019

Background

Previous studies of the prognostic importance of FOXO1 fusion status in patients with rhabdomyosarcoma (RMS) have had conflicting results. We re‐examined risk stratification by adding FOXO1 status to traditional clinical prognostic factors in children with localized or metastatic RMS.

Methods

Data from six COG clinical trials (D9602, D9802, D9803, ARST0331, ARTS0431, ARST0531; two studies each for low‐, intermediate‐ and high‐risk patients) accruing previously untreated patients with RMS from 1997 to 2013 yielded 1727 evaluable patients. Survival tree regression for event‐free survival (EFS) was conducted to recursively select prognostic factors for branching and split. Factors included were age, FOXO1, clinical group, histology, nodal status, number of metastatic sites, primary site, sex, tumor size, and presence of metastases in bone/bone marrow, soft tissue, effusions, lung, distant lymph nodes, and other sites. Definition and outcome of the proposed risk groups were compared to existing systems and cross‐validated results.

Results

The 5‐year EFS and overall survival (OS) for evaluable patients were 69% and 79%, respectively. Extent of disease (localized versus metastatic) was the first split (EFS 73% vs 30%; OS 84% vs. 42%). FOXO1 status (positive vs negative) was significant in the second split both for localized (EFS 52% vs 78%; OS 65% vs 88%) and metastatic disease (EFS 6% vs 46%; OS 19% vs 58%).

Conclusions

After metastatic status, FOXO1 status is the most important prognostic factor in patients with RMS and improves risk stratification of patients with localized RMS. Our findings support incorporation of FOXO1 status in risk stratified clinical trials.
Ionic Pd/NHC Catalytic System Enables Recoverable Homogeneous Catalysis: Mechanistic Study and Application in the Mizoroki–Heck Reaction
Authors: Eremin Dmitry B. , Denisova Ekaterina A. , Yu. Kostyukovich Alexander , Martens Jonathan , Berden Giel , Oomens Jos , Khrustalev Victor N. , Chernyshev Victor M. , Ananikov Valentine P.
Published: August 2019

N‐Heterocyclic carbene (NHC) ligands are ubiquitously utilized in catalysis. A common catalyst design model assumes strong M–NHC binding in this metal–ligand framework. In contrast to this common assumption, we demonstrate here that lability and controlled cleavage of the M−NHC bond (rather than its stabilization) could be more important for high‐performance catalysis at low catalyst concentrations. The present study reveals a dynamic stabilization mechanism with labile metal–NHC binding and [PdX3]−[NHC‐R]+ ion pair formation. Access to reactive anionic palladium intermediates formed by dissociation of the NHC ligands and plausible stabilization of the molecular catalyst in solution by interaction with the [NHC‐R]+ azolium ion is of particular importance for an efficient and recyclable catalyst. These ionic Pd/NHC complexes allowed for the first time the recycling of the complex in a well‐defined form with isolation at each cycle. Computational investigation of the reaction mechanism confirms a facile formation of NHC‐free anionic Pd in polar media through either Ph–NHC coupling or reversible H–NHC coupling. The present study formulates novel ideas for M/NHC catalyst design.
Self‐Assembly of a Trithioorthoformate‐Capped Cyclophane and Its Endohedral Inclusion of a Methine Group
Authors: Collins Mary S. , Shear Trevor A. , Smith Elizabeth K. , Strain S. Michael , Zakharov Lev N. , Johnson Darren W.
Published: August 2019

An unusual trithioorthoformate‐capped cyclophane cage was assembled via antimony‐activated iodine oxidation of thiols as confirmed by 1H‐NMR spectroscopy and X‐ray crystallography. The disulfide bridges can undergo desulfurization with hexamethylphosphorous triamide (HMPT) at ambient temperature to capture a trithioether cyclophane cage capped by the trithioorthoformate. In both cages a methine proton points directly into the small cavity. This unexpected structure is hypothesized to have formed as a result of haloform insertion during oxidation.