bluuebunny/crossref_metadata_2025 huggingface dataset:
Concentration of Selected Heavy Metals in Soil and Edible Vegetables in Obanliku Urban Area of Cross River State, Nigeria
Authors: Akpe Michael Akomaye , Odey Joseph , Agwupuye John Akwagiobe
Published: October 2019

The soil and edible vegetable samples were collected from Obanliku Urban Area of Cross River State and were digested and analyzed for the cadmium (Cd), chromium (Cr), iron (Fe) and mercury (Hg) (heavy metals) concentration using Flame Atomic Absorption Spectrometer (AAS) in Chemistry Laboratory, University of Calabar. The eight vegetables were considered such as Amaranthus spp., Corchorus olitorius, Murraya koenigii, Ocimum grattissimum, Solanum melongena, Talinum triangulare, Telfaira occidentalis and Vernonia amygdalina. The results revealed that the mean concentration of the metals in the soil in mgkg-1 ranged from (0.003-0.017) and (0.003-0.015) for Cd, (0.005-0.040) and (0.004-0.038) for Cr, and (0.052-1.541) and (0.050-1.511) for Fe in rainy and dry seasons respectively. Also, the mean concentration of the metals accumulated by the vegetables in mgkg-1 ranged from (0.002-0.010) for Cd, (0.003-0.018) and (0.003-0.016) for Cr, and (0.013-0.175) and (0.013-0.150) for Fe in rainy and dry season respectively. The concentration of Hg was not detected in the soil or vegetables. The mean concentration accumulated by the vegetables and that present in the soil was in the order: Fe > Cr > Cd > Hg. These results showed that there is no significant difference between the amount of metals in the soil or that accumulated by the vegetables in rainy and dry seasons of the year. Also the amount of metals accumulated by most of the vegetables was directly proportional to the amount present in the soil where they are planted. The bioaccumulation ratios and Target Hazard Quotients (THQ) were all less than 1. The results indicate that the concentration of Cd, Cr, Fe & Hg in the soil and vegetables were still low and within the permissible limits of WHO/FAO. Thus, the consumption of the vegetables in the area at the time when this study was carried out may not pose any health risk.
Characterization and Biological Activities of an Alkali Soluble Exopolysaccharide from Acetobacter
Authors: Chandran Hema , Sharma Kanika
Published: October 2019

Natural polysaccharides have received much attention due to the plethora of their applications. Acetobacter sp. MRL 5A (KX082688) produced an alkali soluble exopolysaccharide (20.39 g/L) on sucrose based media during the late log and early stationary phases. The exopolysaccharide was insoluble in water with high moisture-retention ability and produced viscous solutions and gels. The exopolysaccharide contained 40.3% glucose, 34.4% galactose, 22.2% mannose and 3.1% of arabinose monomers revealed by GC. The exopolysaccharide showed emulsifying, flocculating and in-vitro antioxidant activity similar to standard exopolysaccharides like dextran and xanthan. This EPS can be of potential use in food, cosmetic, pharmaceutical and biomedical fields.
The Use of Exam Notes in an Online Mathematics Course
Authors: Capaldi Mindy
Published: October 2019

Many students want to use cheat sheets, or crib notes, on exams. Whether or not those aids actually help them has not been carefully studied. This paper measures 16 students’ notes by scoring the writing density as well as the number of definitions, examples, and mistakes. To consider the effectiveness of the notes, they are matched against exam solutions. This closer look at the content and application of the online students’ notes revealed that they were neither well- made nor well used.
A Reflective Comparison Study of Statistics Course Evaluations by Modality
Authors: Ingalls Victoria
Published: October 2019

Statistics for teacher evaluations in seated and online classes show a glaring difference in both quantitative and qualitative scores. The generalized analysis of the quantitative and qualitative elements of the same course, instructor, assignment as grouped by learning environment provide an opportunity to inform future practice. In this four-year study at a small, private Midwestern university (n = 316 students over 20 course sections), the seated students were much more engaged and satisfied as demonstrated by their response rates, Likert-scale ratings of course and professor, and associated comments. Reflection and best practices were employed in the online course for continuous improvement, but the numeric values for online evaluations remained consistently and significantly lower in mean value. This study concludes with a series of takeaways for enhancing connections with students and increasing their associated evaluation scores.
Saberes profissionais: narrativas de professores na formação docente
Authors: Carmo Edinaldo Medeiros
Published: October 2019

As investigações que tomam como foco os saberes docentes podem contribuir para potencializar a ação pedagógica, além de permitirem elucidar o debate sobre a importância de uma base de conhecimento para formação de professores. Nesse sentido, este texto apresenta resultados de uma pesquisa que teve como objetivo compreender como os estudantes de licenciatura, em processo de formação, constroem os saberes profissionais. Foram tomados como fontes de dados os relatórios de estágio supervisionado, os quais foram analisados por meio da Análise de Conteúdo. Os resultados apontam que os professores em formação inicial constroem seus saberes mediante a análise de situações reais de ensino, articulando reflexivamente teoria e prática. Apontam também que os condicionantes enfrentados na sala de aula, como tempo insuficiente para desenvolver as atividades didático-pedagógicas e a desmotivação dos alunos, foram retraduzidos como desafios constitutivos da prática e, por meio da reflexão, tornaram-se formativos. Assim, ao enfrentarem os problemas reais do ensino, estes professores em formação desenvolveram reflexões acerca do processo de ensino e aprendizagem fundamentais para a constituição dos saberes profissionais.
O ser humano do Ensino de Biologia: uma abordagem fundamentada no autoconhecimento
Authors: Pagan Alice Alexandre
Published: October 2019

Neste trabalho discuto sobre possíveis relações entre o conhecimento sobre a natureza e o autoconhecimento de nossa espécie sobre a própria humanidade. Proponho que as diferentes formas dessas relações de alteridade, de nossa espécie com os demais seres vivos, podem influenciar nas questões raciais, no sexismo e no especismo. O argumento relaciona a desumanização com a subjugação de membros da nossa espécie e das demais, bem como, que a humanização pode ser uma proposta para relações equitativas entre os diferentes seres vivos que habitam este planeta.
Ensino de Biologia nas políticas e políticas no ensino de Biologia: O que ensinamos e aprendemos nos cursos de formação de professores?
Authors: Feitosa Silva José Roberto
Published: October 2019

O trabalho traz reflexões sobre alguns aspectos técnicos e legais, que permeiam os cursos de formação de professores de Ciências e Biologia, por usarem os conhecimentos escolares das disciplinas do ensino básico, referenciados nos conhecimentos científicos oriundos das diversas áreas das Ciências Biológicas. No estudo o autor apoia-se nos pressupostos: o conhecimento veiculado pela ciência norteia o processo formativo de professores; a ausência de discussão sobre ciência e a falta de compreensão da Biologia como ciência autônoma, ancorada em outras ciências, limita o ordenamento dos conteúdos ao longo das disciplinas nos cursos de licenciatura e bacharelado. Sugere-se que: compreender que os sistemas vivos são complexos; que a ciência histórica está presente na biologia, considerando as narrativas históricas como explicações para compreensão de fenômenos não reproduzíveis experimentalmente; que os seres vivos são unidades inseridas em um tempo e provenientes de fenômenos anteriormente ocorridos; que o acaso existe no ordenamento dos seres vivos e portanto, que o reducionismo não pode ser utilizado como ferramenta explicativa dos processos biológicos, traz ao curso de formação de professores um olhar diferenciado ao usar o pensamento holístico, para cada nível de organização biológica. Dessa maneira, usar o conhecimento técnico científico sob nova perspectiva, crítica, holística e não reducionista, possa trazer e fazer sentido à Biologia, não somente como um conjunto de fatos, mas como sentidos e possibilidades de outras compreensões e outros percursos formativos.
Ensino de biologia: políticas de formação e formação política
Authors: Maknamara Marlecio , Jesus Marta Lícia Teles Brito de
Published: October 2019

Trata-se do Editorial do Número Temático Ensino de Biologia: políticas de formação e formação política.
Boletim Faced: gênese de um fazer acadêmico compartilhado e comprometido
Authors: Arapiraca Mary , Luz Ana Maria De Carvalho
Published: October 2019

Com este artigo, intentamos fazer uma retrospectiva do Boletim,

instituído no período de 1984 a 1989, para fazer circular, entre professores,

funcionários e alunos, informes do que acontecia ou estava previsto para

acontecer no âmbito administrativo e acadêmico da Faculdade de Educação da Universidade Federal da Bahia. Nele, tecemos considerações acerca de sua criação e institucionalização, de seu papel na aproximação das funções

universitárias de ensino, pesquisa e extensão, bem como sobre a relação da

universidade com a formação de professores e com o movimento político de

reorganização democrática. Nesse sentido, buscamos oferecer alguma

referência para o processo de constituição de pessoas implicadas com seu

tempo e comprometidas com a busca de caminhos para inibir os atropelos que, ciclicamente, vêm tomando de assalto nossa história.
State profiles on STR and SOR spending released by NASADAD
Authors: Knopf Alison
Published: October 2019

The Substance Abuse and Mental Health Services Administration (SAMHSA) is keeping its evaluations under wraps, but the National Association of State Alcohol and Drug Abuse Directors (NASADAD) has released a state‐specific list of how the State Targeted Response to the Opioid Crisis (STR) and State Opioid Response (SOR) grants are being spent.
Recent Progress on 2D Noble‐Transition‐Metal Dichalcogenides
Authors: Pi Lejing , Li Liang , Liu Kailang , Zhang Qingfu , Li Huiqiao , Zhai Tianyou
Published: October 2019

Emerging classes of 2D noble‐transition‐metal dichalcogenides (NTMDs) stand out for their unique structure and novel physical properties in recent years. With the nearly full occupation of the d orbitals, 2D NTMDs are expected to be more attractive due to the unique interlayer vibrational behaviors and largely tunable electronic structures compared to most transition metal dichalcogenide semiconductors. The novel properties of 2D NTMDs have stimulated various applications in electronics, optoelectronics, catalysis, and sensors. Here, the latest development of 2D NTMDs are reviewed from the perspective of structure characterization, preparation, and application. Based on the recent research, the conclusions and outlook for these rising 2D NTMDs are presented.
Electronically Coupled Uranium and Iron Oxide Heterojunctions as Efficient Water Oxidation Catalysts
Authors: Leduc Jennifer , Gönüllü Yakup , Ruoko Tero‐Petri , Fischer Thomas , Mayrhofer Leonhard , Tkachenko Nikolai V. , Dong Chung‐Li , Held Alexander , Moseler Michael , Mathur Sanjay
Published: October 2019

The most critical challenge faced in realizing a high efficiency photoelectrochemical water splitting process is the lack of suitable photoanodes enabling the transfer of four electrons involved in the complex oxygen evolution reaction (OER). Uranium oxides are efficient catalysts due to their wide range optical absorption (Eg≈ 1.8–3.2 eV), high photoconductivity, and multiple valence switching among uranium centers that improves the charge propagation kinetics. Herein, thin films of depleted uranium oxide (U3O8) are demonstrated grown via chemical vapor deposition effectively accelerate the OER in conjunction with hematite (α‐Fe2O3) overlayers through a built‐in potential at the interface. Density functional theory simulations demonstrate that the multivalence of U and Fe ions induce the adjustment of the band alignment subject to the concentration of interfacial Fe ions. In general, the equilibrium state depicts a type II band edge as the favored alignment, which improves charge‐transfer processes as observed in transient and X‐ray absorption (TAS and XAS) spectroscopy. The enhanced water splitting photocurrent density of the heterostructures (J= 2.42 mA cm−2) demonstrates the unexplored potential of uranium oxide in artificial photosynthesis.
On‐Body Bioelectronics: Wearable Biofuel Cells for Bioenergy Harvesting and Self‐Powered Biosensing
Authors: Jeerapan Itthipon , Sempionatto Juliane R. , Wang Joseph
Published: October 2019

The growing power demands of wearable electronic devices have stimulated the development of on‐body energy‐harvesting strategies. This article reviews the recent progress on rapidly emerging wearable biofuel cells (BFCs), along with related challenges and prospects. Advanced on‐body BFCs in various wearable platforms, e.g., textiles, patches, temporary tattoo, or contact lenses, enable attractive advantages for bioenergy harnessing and self‐powered biosensing. These noninvasive BFCs open up unique opportunities for utilizing bioenergy or monitoring biomarkers present in biofluids, e.g., sweat, saliva, interstitial fluid, and tears, toward new biomedical, fitness, or defense applications. However, the realization of effective wearable BFC requires high‐quality enzyme‐electronic interface with efficient enzymatic and electrochemical processes and mechanical flexibility. Understanding the kinetics and mechanisms involved in the electron transfer process, as well as enzyme immobilization techniques, is essential for efficient and stable bioenergy harvesting under diverse mechanical strains and changing operational conditions expected in different biofluids and in a variety of outdoor activities. These key challenges of wearable BFCs are discussed along with potential solutions and future prospects. Understanding these obstacles and opportunities is crucial for transforming traditional bench‐top BFCs to effective and successful wearable BFCs.
Controlled Growth of Single‐Crystal Graphene Films
Authors: Zhang Jincan , Lin Li , Jia Kaicheng , Sun Luzhao , Peng Hailin , Liu Zhongfan
Published: October 2019

Grain boundaries produced during material synthesis affect both the intrinsic properties of materials and their potential for high‐end applications. This effect is commonly observed in graphene film grown using chemical vapor deposition and therefore caused intense interest in controlled growth of grain‐boundary‐free graphene single crystals in the past ten years. The main methods for enlarging graphene domain size and reducing graphene grain boundary density are classified into single‐seed and multiseed approaches, wherein reduction of nucleation density and alignment of nucleation orientation are respectively realized in the nucleation stage. On this basis, detailed synthesis strategies, corresponding mechanisms, and key parameters in the representative methods of these two approaches are separately reviewed, with the aim of providing comprehensive knowledge and a snapshot of the latest status of controlled growth of single‐crystal graphene films. Finally, perspectives on opportunities and challenges in synthesizing large‐area single‐crystal graphene films are discussed.
Ferroelectric Tunnel Junctions: Modulations on the Potential Barrier
Authors: Wen Zheng , Wu Di
Published: October 2019

Recently, ferroelectric tunnel junctions (FTJs) have attracted considerable attention for potential applications in next‐generation memories, owing to attractive advantages such as high‐density of data storage, nondestructive readout, fast write/read access, and low energy consumption. Herein, recent progress regarding FTJ devices is reviewed with an emphasis on the modulation of the potential barrier. Electronic and ionic approaches that modulate the ferroelectric barriers themselves and/or induce extra barriers in electrodes or at ferroelectric/electrode interfaces are discussed with the enhancement of memory performance. Emerging physics, such as nanoscale ferroelectricity, resonant tunneling, and interfacial metallization, and the applications of FTJs in nonvolatile data storage, neuromorphic synapse emulation, and electromagnetic multistate memory are summarized. Finally, challenges and perspectives of FTJ devices are underlined.
Cyclodextrin‐Derived Intrinsically Bioactive Nanoparticles for Treatment of Acute and Chronic Inflammatory Diseases
Authors: Guo Jiawei , Li Dandan , Tao Hui , Li Gang , Liu Renfeng , Dou Yin , Jin Taotao , Li Lanlan , Huang Jun , Hu Houyuan , Zhang Jianxiang
Published: October 2019

Inflammation is a common cause of many acute and chronic inflammatory diseases. A major limitation of existing anti‐inflammatory therapeutics is that they cannot simultaneously regulate pro‐inflammatory cytokine production, oxidative stress, and recruitment of neutrophils and macrophages. To overcome this limitation, nanoparticles (NPs) with multiple pharmacological activities are synthesized, using a chemically modified cyclic oligosaccharide. The manufacture of this type of bioactive, saccharide material‐based NPs (defined as LCD NP) is straightforward, cost‐effective, and scalable. Functionally, LCD NP effectively inhibits inflammatory response, oxidative stress, and cell migration for both neutrophils and macrophages, two major players of inflammation. Therapeutically, LCD NP shows desirable efficacies for the treatment of acute and chronic inflammatory diseases in mouse models of peritonitis, acute lung injury, and atherosclerosis. Mechanistically, the therapeutic benefits of LCD NP are achieved by inhibiting neutrophil‐mediated inflammatory macrophage recruitment and by preventing subsequent pro‐inflammatory events. In addition, LCD NP shows good safety profile in a mouse model. Thus, LCD NP can serve as an effective anti‐inflammatory nanotherapy for the treatment of inflammatory diseases mainly associated with neutrophil and macrophage infiltration.
Kirigami‐Inspired Textile Electronics: K.I.T.E.
Authors: Li Braden M. , Kim Inhwan , Zhou Ying , Mills Amanda C. , Flewwellin Tashana J. , Jur Jesse S.
Published: October 2019

Electronic textiles (e‐textiles) are in prime position to revolutionize the field of wearable electronics owing to their ubiquitous use and universal acceptance. However, mechanical incompatibility between the rigid conductive components on the soft textile platforms creates fragile e‐textile systems with poor electromechanical attributes. In this work, a novel design strategy to inkjet print reactive silver inks onto woven textiles with Kirigami‐inspired patterning to create e‐textiles with enhanced electromechanical features is introduced. By controlling the print processing and curing conditions, uniform conductive coatings with sheet resistances of 0.09 Ω sq−1 are achieved such that they do not interfere with the textiles innate flexibility, breathability, comfort, and fabric hand. The electromechanical coupling of the printed textiles shows a direct dependence on the anisotropic nature of the woven structures. Introducing Kirigami patterning creates robust devices that enhance and stabilize the electrical conductivity (ΔR/R0 < −20%) over large strain regimes (>150%). Furthermore, an electrocardiogram monitoring system fabricated from Kirigami e‐textiles exhibits stable signal acquisition under extreme deformations from arm joint flexion. The distinct properties of Kirigami patterning on e‐textiles enable unprecedented electromechanical performance in wearable textile electronics.
Excretable Lanthanide Nanoparticle for Biomedical Imaging and Surgical Navigation in the Second Near‐Infrared Window
Authors: Li Daifeng , He Shuqing , Wu Yifan , Liu Jianqiang , Liu Qiang , Chang Baisong , Zhang Qing , Xiang Zhanhong , Yuan Ying , Jian Chao , Yu Aixi , Cheng Zhen
Published: October 2019

Recently, various second near‐infrared window (NIR‐II, 1000–1700 nm) fluorophores have been synthesized for in vivo imaging with nonradiation, high resolution, and low autofluorescence. However, most of the NIR‐II fluorophores, especially inorganic nanoprobes, are mainly retained in the reticuloendothelial system (RES) such as the liver and spleen, leading to long‐term safety concerns. Herein, a type of lanthanide‐based excretable NIR‐II nanoparticle, RENPs@Lips, which can be quickly cleared out of body after intravenous administration with half‐lives of 23.0 h for the liver and 14.9 h for the spleen, is reported. Interestingly, over 90% of RENPs@Lips can be excreted through a hepatobiliary system within 72 h postinjection. The moderate blood half‐time (T1/2 = 17.96 min) allows for multifunctional applications in delineating the hemodynamics of vascular disorders (artery thrombosis, ischemia, and tumor angiogenesis) and monitoring blood perfusion in response to acute ischemia. In addition, RENPs@Lips exhibit high performance in identifying orthotopic tumor vessels intraoperatively and embolization surgery under NIR‐II imaging navigation. Moreover, excellent signal‐to‐background ratio (SBR) is successfully achieved to facilitate sentinel lymph nodes biopsy (SLNB) with tumor‐bearing mice. The high biocompatibility, favorable excretability, and outstanding optical properties warrant RENPs@Lips as novel promising NIR‐II nanoparticles for future applications and translation into an interdisciplinary amalgamation of research in diverse fields.
Heterostructure Engineering of a Reverse Water Gas Shift Photocatalyst
Authors: Wang Hong , Jia Jia , Wang Lu , Butler Keith , Song Rui , Casillas Gilberto , He Le , Kherani Nazir P. , Perovic Doug D. , Jing Liqiang , Walsh Aron , Dittmeyer Roland , Ozin Geoffrey A.
Published: October 2019

To achieve substantial reductions in CO2 emissions, catalysts for the photoreduction of CO2 into value‐added chemicals and fuels will most likely be at the heart of key renewable‐energy technologies. Despite tremendous efforts, developing highly active and selective CO2 reduction photocatalysts remains a great challenge. Herein, a metal oxide heterostructure engineering strategy that enables the gas‐phase, photocatalytic, heterogeneous hydrogenation of CO2 to CO with high performance metrics (i.e., the conversion rate of CO2 to CO reached as high as 1400 µmol g cat−1 h−1) is reported. The catalyst is comprised of indium oxide nanocrystals, In2O3−x(OH)y, nucleated and grown on the surface of niobium pentoxide (Nb2O5) nanorods. The heterostructure between In2O3−x(OH)y nanocrystals and the Nb2O5 nanorod support increases the concentration of oxygen vacancies and prolongs excited state (electron and hole) lifetimes. Together, these effects result in a dramatically improved photocatalytic performance compared to the isolated In2O3−x(OH)y material. The defect optimized heterostructure exhibits a 44‐fold higher conversion rate than pristine In2O3−x(OH)y. It also exhibits selective conversion of CO2 to CO as well as long‐term operational stability.
Additive Engineering for Efficient and Stable Perovskite Solar Cells
Authors: Zhang Fei , Zhu Kai
Published: October 2019

Perovskite solar cells (PSCs) have reached a certified 25.2% efficiency in 2019 due to their high absorption coefficient, high carrier mobility, long diffusion length, and tunable direct bandgap. However, due to the nature of solution processing and rapid crystal growth of perovskite thin films, a variety of defects can form as a result of the precursor compositions and processing conditions. The use of additives can affect perovskite crystallization and film formation, defect passivation in the bulk and/or at the surface, as well as influence the interface tuning of structure and energetics. Here, recent progress in additive engineering during perovskite film formation is discussed according to the following common categories: Lewis acid (e.g., metal cations, fullerene derivatives), Lewis base based on the donor type (e.g., O‐donor, S‐donor, and N‐donor), ammonium salts, low‐dimensional perovskites, and ionic liquid. Various additive‐assisted strategies for interface optimization are then summarized; additives include modifiers to improve electron‐ and hole‐transport layers as well as those to modify perovskite surface properties. Finally, an outlook is provided on research trends with respect to additive engineering in PSC development.
Vertical coordination mechanisms and farm performance amongst smallholder rice farmers in northern Ghana
Authors: Abdul‐Rahaman Awal , Abdulai Awudu
Published: October 2019

Despite the fact that contracting facilitates farmer participation in agrifood value chains, evidence on farmers’ participation in different forms of contracts and the impact on farm performance is still limited. This study examines the determinants and impacts of vertical coordination mechanism‐spot market transactions, written, and verbal contract‐on‐farm performance of rice farmers in northern Ghana, using a multinomial BFG model to account for selectivity bias. The findings indicate that vertical coordination participation decision is significantly influenced by age, access to credit, labor, association membership, and sales to institutional buyers. The empirical results also reveal significant gains in farm performance outcomes from participating in written and verbal contracts, relative to spot market transactions.
Association between second to fourth digit ratio and personality among Indian men
Authors: Bagepally Bhavani S. , Majumder Joydeep , Kotadiya Sanjay M.
Published: October 2019

Objectives

To examine the relationship between the personality domains with the second to fourth digit ratio (2d:4d); a prenatal testosterone exposure marker.

Methods

The 2d:4d for both hands was measured for the Indian male subjects' (n = 994). Ten‐item personality inventory and displaced aggression questionnaire data were collected in a self‐reported proforma in this cross sectional study with a convenient sampling approach.

Results

The personality traits, namely openness to new experiences, carelessness, and self‐discipline were significantly differed between lower‐half and higher‐half of 2d:4d by median split. The right hand 2d:4d was positively correlated with open to new experiences and negatively correlated with disorganization, carelessness, and revenge planning. The left hand 2d:4d was positively correlated with aggression. On binary logistic regression, openness was positively associated while carelessness was negatively associated with the right hand 2d:4d and self‐discipline trait was negatively associated with the left hand 2d:4d.

Conclusion

This study affirmed the link between 2d:4d and domains of Big Five personality factors among Indian men and inverse relationship between 2d:4d and more “female” hands in the domains of disorganization, carelessness, and revenge planning even in men, emphasizing the effect of prenatal testosterone exposure on human personality.
Covalent‐Allosteric Inhibitors to Achieve Akt Isoform‐Selectivity
Authors: Quambusch Lena , Landel Ina , Depta Laura , Weisner Jörn , Uhlenbrock Niklas , Müller Matthias P. , Glanemann Franziska , Althoff Kristina , Siveke Jens T. , Rauh Daniel
Published: October 2019

Isoforms of protein kinase Akt are involved in essential processes including cell proliferation, survival, and metabolism. However, their individual roles in health and disease have not been thoroughly evaluated. Thus, there is an urgent need for perturbation studies, preferably mediated by highly selective bioactive small molecules. Herein, we present a structure‐guided approach for the design of structurally diverse and pharmacologically beneficial covalent‐allosteric modifiers, which enabled an investigation of the isoform‐specific preferences and the important residues within the allosteric site of the different isoforms. The biochemical, cellular, and structural evaluations revealed interactions responsible for the selective binding profiles. The isoform‐selective covalent‐allosteric Akt inhibitors that emerged from this approach showed a conclusive structure–activity relationship and broke ground in the development of selective probes to delineate the isoform‐specific functions of Akt kinases.
Modular Access to Eight‐Membered N‐Heterocycles by Directed Carbonylative C−C Bond Activation of Aminocyclopropanes
Authors: Boyd Olivia , Wang Gang‐Wei , Sokolova Olga O. , Calow Adam D. J. , Bertrand Sophie M. , Bower John F.
Published: October 2019

Aminocyclopropanes equipped with pendant nucleophiles undergo carbonylative heterocyclization triggered by C−C bond activation to generate eight‐membered N‐heterocycles. In these processes, intramolecular “capture” of a rhodacyclopentanone intermediate by an aryl or N‐based nucleophile is followed by C−C or C−N bond‐forming “collapse” to the targets. These studies demonstrate how the combination of cyclopropane strain release and the templating effect of catalytically generated metallacycles can be harnessed to enable otherwise challenging medium ring closures.
RAFT‐vermittelte polymerisationsinduzierte Selbstorganisation (PISA)
Authors: D'Agosto Franck , Rieger Jutta , Lansalot Muriel
Published: October 2019

Nach einem kurzen historischen Überblick zur polymerisationsvermittelten Selbstorganisation (polymerization‐induced self assembly, PISA) im Bereich der Polymerchemie werden in diesem Aufsatz die Grundlagen des PISA‐Mechanismus erklärt. Darüber hinaus behandelt der Aufsatz einige Eigenschaften und Einschränkungen von RAFT‐vermittelten PISA‐Systemen im Hinblick auf die Auswahl der beteiligten Komponenten, die Art und Steuerung der synthetisierbaren Nanoobjekte und Morphologien sowie mögliche Anwendungen.
Improving the thermal and mechanical properties of poly(arylene ether nitrile) films through blending high‐ and low‐molecular‐weight polymers
Authors: Tong Lifen , Yang Guangyao , Lei Xiting , You Yong , Liu Xiaobo
Published: October 2019

In present work, novel phthalonitrile end‐capping poly(arylene ether nitrile)‐phenyl (PEN‐Ph) films with excellent mechanical properties as well as high glass transition temperature were prepared through blending high‐molecular‐weight PEN‐Ph (HMW PEN‐Ph) and low‐molecular‐weight PEN‐Ph (LMW PEN‐Ph). Then, the thermal and mechanical properties of the samples with different mass ratio of HMW PEN‐Ph and LMW PEN‐Ph were studied, and the effect of heat‐treatment temperature on the performance of films was also investigated. The analysis results indicate that the crosslinking density as well as film formation can be controlled by adjusting the mass ratio of HMW PEN‐Ph to LMW PEN‐Ph. Besides, when the mass ratio of HMW PEN‐Ph to LMW PEN‐Ph is 5:2, the film treated at 340 °C possesses the best thermal and mechanical properties, with Tg of 218.9 °C and tensile strength of 104.8 MPa, increased by 10.9 °C and 16.6 MPa than pure HMW PEN‐Ph film, respectively. Thus, the presence of LMW PEN‐Ph makes the thermal and mechanical properties of the films improve dramatically, providing the possibility for the application in the electronics and high‐temperature resistant fields. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48457.
Effect of processing conditions on wood and glass fiber length attrition during twin screw composite compounding
Authors: Dickson Alan , Teuber Laura , Gaugler Marc , Sandquist David
Published: October 2019

In this study, we compare the effect of twin‐screw extrusion processing on the attrition of wood fibers (WFs) with glass fiber. The effects of process variables and screw design on fiber length were investigated by performing a range of dead‐stop experiments where the extruder was stopped, opened‐up, and compound removed from the screw elements. Fibers, chemically extracted from the polypropylene matrix, were analyzed for length and width using a commercial fiber analyzer. It was found that WF length attrition and composite properties were less affected by screw design and twin‐screw processing conditions (feed rate and screw speed) than glass fiber. Length weighted fiber length and X50 length (a measure used in particle size analysis) were equally correlated with process conditions and composite performance for both fiber types. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48551.
Removal of dyes by poly(p‐phenylene terephthamide)/polyvinylidene fluoride hollow fiber in‐situ blend membranes
Authors: Shi Wenying , Zeng Xianhua , Li Hongbin , Zhang Haixia , Qin Xiaohong , Zhou Rong
Published: October 2019

In order to obtain the compatible poly(p‐phenylene terephthalamide) (PPTA)/polyvinylidene fluoride (PVDF) blend membranes, the casting solution was synthesized via the in situ polycondensation process and flat sheet blend membranes were successfully prepared through the immersion precipitation phase inversion method in our previous study. In this study, the polycondensation solution was directly used as the spinning dope to fabricate PPTA/PVDF hollow fiber in‐situ blend membrane by the dry‐wet spinning technique. Hollow fiber membranes were employed to remove the dyes including Congo red (CR) and methylene blue (MB) from the dyeing liquor. Effects of operation conditions on dye rejection and membrane water flux were investigated. With the increase of operation pressure, feed concentration and feed temperature, dye rejection rates gradually decreased, but the rejection value of CR and MB still remained above 99.5%. On the contrary, the permeation water flux basically increased. During the continuous dye filtration of 300 min, hollow fiber membrane can maintain high dye rejection rates and stable water flux. The combination method of physical backwashing and chemical cleaning can effectively alleviate membrane fouling and recover membrane water flux. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48569.
Why most insects have very low proportions of C20 polyunsaturated fatty acids: The oxidative stress hypothesis
Authors: Stanley David , Kim Yonggyun
Published: October 2019

Eicosanoids, a group of C20 oxygenated polyunsaturated fatty acids (PUFAs), mediate various physiological processes, such as immunity, reproduction, excretion, and metabolism in insects. Arachidonic acid (AA) is used for the main precursor for the production of various eicosanoids. However, most terrestrial insects possess relatively low AA levels. Insects are presumed to be evolved since the Paleozoic era, at which oxygen levels might be much higher than current conditions. Compared with other animals, they exhibit relatively high metabolic rates with the well‐developed tracheal system, which directly supply enough oxygen to active tissues like flight muscles. This might allow insects to be susceptible to reactive oxygen species (ROS) generated from high oxidative catabolism. Long‐chain PUFAs including AA is usually reacted with ROS and become peroxidized. Peroxidized PUFAs cause various cellular damage. Thus, we propose a hypothesis that terrestrial insects minimize AA levels to minimize oxidative stress.
Latent variable models for harmonization of test scores: A case study on memory
Authors: van den Heuvel Edwin R. , Griffith Lauren E. , Sohel Nazmul , Fortier Isabel , Muniz‐Terrera Graciela , Raina Parminder
Published: October 2019

Combining data from different studies has a long tradition within the scientific community. It requires that the same information is collected from each study to be able to pool individual data. When studies have implemented different methods or used different instruments (e.g., questionnaires) for measuring the same characteristics or constructs, the observed variables need to be harmonized in some way to obtain equivalent content information across studies. This paper formulates the main concepts for harmonizing test scores from different observational studies in terms of latent variable models. The concepts are formulated in terms of calibration, invariance, and exchangeability. Although similar ideas are present in measurement reliability and test equating, harmonization is different from measurement invariance and generalizes test equating. In addition, if a test score needs to be transformed to another test score, harmonization of variables is only possible under specific conditions. Observed test scores that connect all of the different studies, are necessary to be able to test the underlying assumptions of harmonization. The concepts of harmonization are illustrated on multiple memory test scores from three different Canadian studies.
Manipulation of the dually thermoresponsive behavior of peptide‐based vesicles through modification of collagen‐like peptide domains
Authors: Dunshee Lucas C. , Sullivan Millicent O. , Kiick Kristi L.
Published: October 2019

Materials that respond to temporally defined exogenous cues continue to be an active pursuit of research toward on‐demand nanoparticle drug delivery applications, and using one or more exogenous temperature stimuli could significantly expand the application of nanoparticle‐based drug delivery formulations under both hyperthermal and hypothermal conditions. Previously we have reported the development of a biocompatible and thermoresponsive elastin‐b‐collagen‐like polypeptide (ELP‐CLP) conjugate that is capable of self‐assembling into vesicles and encapsulating small molecule therapeutics that can be delivered at different rates via a single temperature stimulus. Herein we report the evaluation of multiple ELP‐CLP conjugates, demonstrating that the inverse transition temperature (Tt) of the ELP‐CLPs can be manipulated by modifying the melting temperature (Tm) of the CLP domain, and that the overall hydrophilicity of the ELP‐CLP conjugate also may alter the Tt. Based on these design parameters, we demonstrate that the ELP‐CLP sequence (VPGFG)6‐(GPO)7GG can self‐assemble into stable vesicles at 25°C and dissociate at elevated temperatures by means of the unfolding of the CLP domain above its Tm. We also demonstrate here for the first time the ability of this ELP‐CLP vesicle to dissociate via a hypothermic temperature stimulus by means of exploiting the inverse transition temperature (Tt) phenomena found in ELPs. The development of design rules for manipulating the thermal properties of these bioconjugates will enable future modifications to either the ELP or CLP sequences to more finely tune the transitions of the conjugates for specific biomedical applications.
A Fast and Easy Method for Specific Detection of Circular RNA by Rolling‐Circle Amplification
Authors: Boss Marcel , Arenz Christoph
Published: October 2019

Circular RNAs (circRNAs) represent a new class of usually noncoding transcripts with largely unknown functions. Their research is hampered not least by the inapplicability of traditional analytical methods. Herein we describe a rapid and easy assay for the detection of natural circRNA, based on rolling‐circle amplification (RCA). This technique does not require the use of fluorescently labeled RNA or DNA and can specifically detect circular RNA in the presence of a 1000‐fold excess of the same linear RNA. Only standard devices such as (quantitative) PCR cyclers and gel electrophoresis are used.
Rhodium Complexes in P−H Bond Activation Reactions
Authors: Varela‐Izquierdo Víctor , Geer Ana M. , de Bruin Bas , López José A. , Ciriano Miguel A. , Tejel Cristina
Published: October 2019

The feasibility of oxidative addition of the P−H bond of PHPh2 to a series of rhodium complexes to give mononuclear hydrido‐phosphanido complexes has been analyzed. Three main scenarios have been found depending on the nature of the L ligand added to [Rh(Tp)(C2H4)(PHPh2)] (Tp= hydridotris(pyrazolyl)borate): i) clean and quantitative reactions to terminal hydrido‐phosphanido complexes [RhTp(H)(PPh2)(L)] (L=PMe3, PMe2Ph and PHPh2), ii) equilibria between RhI and RhIII species: [RhTp(H)(PPh2)(L)]⇄[RhTp(PHPh2)(L)] (L=PMePh2, PPh3) and iii) a simple ethylene replacement to give the rhodium(I) complexes [Rh(κ2‐Tp)(L)(PHPh2)] (L=NHCs‐type ligands). The position of the P−H oxidative addition–reductive elimination equilibrium is mainly determined by sterics influencing the entropy contribution of the reaction. When ethylene was used as a ligand, the unique rhodaphosphacyclobutane complex [Rh(Tp)(η1‐Et)(κC,P‐CH2CH2PPh2)] was obtained. DFT calculations revealed that the reaction proceeds through the rate limiting oxidative addition of the P−H bond, followed by a low‐barrier sequence of reaction steps involving ethylene insertion into the Rh−H and Rh−P bonds. In addition, oxidative addition of the P−H bond in OPHPh2 to [Rh(Tp)(C2H4)(PHPh2)] gave the related hydride complex [RhTp(H)(PHPh2)(POPh2)], but ethyl complexes resulted from hydride insertion into the Rh−ethylene bond in the reaction with [Rh(Tp)(C2H4)2].
Light‐Induced Tetrazole‐Quinone 1,3‐Dipolar Cycloadditions
Authors: Ortiz‐Rojano Laura , Rojas‐Martín Jaime , Rodríguez‐Diaz Ciro , Carreño M. Carmen , Ribagorda Maria
Published: October 2019

Quinones were firstly used as dipolarophiles in a photoclick 1,3‐cycloaddition with 2,5‐diaryltetrazoles, as photoactivatable predipoles, providing a novel and efficient access to three types of pyrazole‐fused quinones (indazoledione derivatives). Distinctive features of this protocol include the use of light as the unique reagent and readily available, stable, and easy to handle starting materials and good to excellent yields. Photophysical and electrochemical properties of the quinones and their potential application as photoredox catalysts are also detailed.
TiO2 based nanopowder coatings over stainless steel plates for UV‐C photocatalytic degradation of methylene blue
Authors: Jiao Yongmei , Basiliko Nathan , Kovala A. Thomas , Shepherd Jeffrey , Shang Helen , Scott John A.
Published: October 2019

Immobilizing the photocatalyst in a water treatment process design is essential; however, the immobilization method may affect the photoactivity of the photocatalyst. In this work, photocatalyst powders were successfully coated on 316 L stainless steel plates by a novel brush coating method. Three combinations of photocatalyst mixtures (pure TiO2 anatase, anatase doped with WO3, or TiO2 rutile) were and annealed at different temperatures between 460‐540°C. The ~ 10 μm thick coatings demonstrated full plate coverage and strong adhesion and adequate durability. Surface roughness increased with annealing temperature. The doping and annealing process enabled band gap reduction to the visible light spectrum for all coatings, with the smallest band gap being 2.48 eV (1 eV = 1.6 × 10−19 J). Subsequent methylene blue degradation tests under UV‐C showed that the coatings annealed in 460°C exhibited the best performance and with the highest degradation rate constant of 5.59 hours−1.
A theoretical study of the reverse water‐gas shift reaction on Ni(111) and Ni(311) surfaces
Authors: Zhang Min , Zijlstra Bart , Filot Ivo A. W. , Li Fang , Wang Haiou , Li Jingde , Hensen Emiel J. M.
Published: October 2019

This paper presents a systematic comparison study of the surface redox reaction mechanism for reverse water‐gas shift (RWGS) over Ni(111) and Ni(311) surfaces. Specifically, the most stable surface intermediates and the reaction kinetics involved in the direct CO2 activation and water formation steps are computed with density functional theory calculations and compared for the two different Ni surfaces. The results show that CO2, CO, O, H, OH, and H2O species adsorb stronger on Ni(311) than on Ni(111). Compared to Ni(111), the overall barriers for direct CO2 activation and water formation on Ni(311) are lower by 23 and 17 kJ/mol, respectively. These observations indicate that the RWGS reaction through the surface redox mechanism should be preferred on Ni(311).
A Constant Potential Molecular Dynamics Simulation Study of the Atomic‐Scale Structure of Water Surfaces Near Electrodes
Authors: Yang Pengli , Wang Zhenxing , Liang Zun , Liang Hongtao , Yang Yang
Published: October 2019

Summary of main observation and conclusion

Novel and technologically important processes and phenomena arise at water surfaces in the presence of electric fields. However, experimental measurements on water surfaces are challenging, and the results are scarce and inconclusive. In this work, the constant potential molecular dynamics method, in which the electrode charges are allowed to fluctuate to keep the electric potential fixed, was implemented in the study of a near‐electrode water surface systems. This simulation system was set up with a vapor/liquid‐water/vapor slab and two electrodes under different sets of applied electrostatic potential, yielding i) a detailed characterization of the external E‐field dependent electrostatic potential/density/dipole moment density profiles, and ii) the relationship between the water surface width and the applied electrode voltage differences which has been rarely reported. The adjustments in the number density profiles in the vicinity of water surfaces due to external E‐fields were observed, while the capillary interfacial widths for the surfaces near both cathode and anode were found with different increment rates under increasing E‐fields. By examining dipole density profiles across the water surfaces, we found that external E‐field induced polarization occurs in both bulk and surface regimes, yet the surface polarization densities vary asymmetrically with respect to the increasing E‐fields. Detailed discussions were carried out to explain the correlation between water surface tension and surface widths, as well as the interplay between the surface polarization densities and the hydrogen bond network structure. We conclude that the mechanical and structural properties of the water surfaces could be tuned by both magnitude and direction of the strong external E‐fields. We also recognize that more surface properties with application value, such as dielectric permittivity tensor or surface potential, could also be regulated by the external E‐fields.
Design and Synthesis of a Series of Novel Macrocycle Janus Kinase 2 Inhibitors
Authors: Wang Yanling , Ge Huan , Wang Disha , He Huan , Li Lu , Diao Yanyan , Shen Zihao , Zhu Lili , Li Shiliang , Zhao Zhenjiang , Li Honglin
Published: October 2019

Summary of main observation and conclusion

Macrocycle has attracted the attention of many researchers in the field of medicinal chemistry due to its unique advantages and good prospects, but the difficulties in drug design and synthesis of macrocycle limit its applications. In this study, a series of macrocyclic derivatives designed from anaplastic lymphoma kinase (ALK) inhibitor lorlatinib were synthesized as Janus kinase 2 (JAK2) selective inhibitors. Among them, 17f had the best inhibitory activity (IC50 = 0.177 μmol·L–1) and selectivity for JAK2 over JAK1 and JAK3, which indicated that design of the macrocyclic derivatives might be a feasible strategy for the discovery of novel selective JAK2 inhibitors.