bluuebunny/crossref_metadata_2025 huggingface dataset:
A IMPORTÂNCIA DA FORMA ESTRUTURAL: OBRAS DE MAILLART E MENN [ The importance of structural forms: Maillart and Menn`s works ]
Authors: Neto Tiago Ferreira Campos , Brandão Jéssica Faria , Sánchez José Manoel Morales
Published: August 2018

RESUMO: As estruturas fornecem a chave para o renascimento da vida pública. Essa nova visão levou à criação de uma nova classe de profissionais, os engenheiros modernos. Entre eles, destacam-se Robert Maillart e Christian Menn, que produziram obras de arte em concreto armado entre os finais do século XIX e XX. Sabendo que a primeira fase de produção de Menn foi influenciada pela arte e técnica de Maillart, este artigo busca avaliar as semelhanças nas relações forma-função e estética das obras de maior representatividade dos dois artistas estruturais por meio da aplicação de análises computacionais dos aspectos projetuais. A ponte Salginatobel, obra de Maillart, foi construída em 1930 e desde então tem sido reconhecida por sua impressionante nova forma de arte e pela sua eficiência econômica e estrutural. A ponte Ganter, obra de Menn, possui qualidade estética sem violar as considerações técnicas, tendo o maior vão livre das pontes da Suíça. Por meio de análises computacionais simplificadas as duas pontes foram estudadas e notou-se que Menn usa a técnica de caixão perdido criada por Maillart para vencer grandes vãos, entretanto os momentos fletores atingiram valores elevados, exigindo que o artista usasse do sistema de protensão para executar sua obra. Observou-se semelhança na estética entre as obras analisadas e no comportamento dos esforços internos, atestando que Menn, ao projetar sua obra, espelhou-se nas formas estruturais criadas por Maillart. ABSTRACT: Structures provide the key to revive the public life. This new vision led to the creation of a new class of professionals, the modern engineers. Among them, Robert Maillart and Christian Menn stand out because both produced reinforced concrete works of art between the late nineteenth and twentieth centuries. Considering that the first Menn’s production phase was influenced by Maillart’s art and technique, this paper aims to evaluate the similarities in the form-function and aesthetic relations between the most representative works of these two structural artists through the application of computational analysis of design aspects. The Salginatobel Bridge, Maillart’s work, was built in 1930 and has been recognized for its impressive new art form and its economic and structural efficiency since then. The Ganter Bridge, Menn`s work, has aesthetic quality without violating technical considerations and with the largest span of Switzerland bridges. By means of simplified computational analysis the two bridges were studied and it was noticed that Menn uses Maillart`s hollow-box technique to overcome large spans, however the bending moments reached high values, requiring the usage of a pretension system. Similarities were observed in the aesthetics between the analyzed bridges and in the behavior of the internal efforts, attesting that Menn`s work was mirrored in Maillart`s structural forms.
SIMULAÇÃO NÚMERICA DO COMPORTAMENTO DE VIGAS MISTAS DE AÇO E CONCRETO PROTENDIDAS [ Numerical behavior analysis of prestressed steel-concrete composite beams ]
Authors: Da Silva Elder Nogueira , De Souza Alex Sander Clemente
Published: August 2018

RESUMO: O presente trabalho apresenta uma metodologia para análise numérica de vigas mistas de aço e concreto protendidas utilizando o pacote computacional ABAQUS®, que permite modelagens via método dos elementos finitos. A metodologia aborda aspectos relacionados a escolha dos elementos finitos utilizados, geometria das malhas, relações constitutivas dos materiais, condições de acoplamento e vinculação entre os materiais e procedimentos de aplicação dos carregamentos, com o objetivo de simular o comportamento da estrutura. A interação entre laje de concreto e viga de aço foi modelada com conectores e elementos de contato e considerando somente o acoplamento das redes de elementos finitos da laje e da viga. A validação do modelo numérico foi realizada através da correlação entre os resultados numéricos e experimentais disponíveis na literatura. Para ambas as formas de vinculação laje-perfil, o modelo numérico representou de forma satisfatória o comportamento observado experimentalmente. Nos casos em que foram modelados os conectores de cisalhamento as vigas apresentaram menor rigidez e consequentemente melhor correlação entre resultados numéricos e experimentais.ABSTRACT: This paper reports a methodology adopted to represent the behavior of prestressed steel concrete composite beam by finite element models using software ABAQUS®. The methodology presents aspects related to the choice of finite elements types, mesh geometry, constitutive relations of materials, boundary conditions, steel-concrete interaction and sequence of loading.  The interaction between the concrete slab and the steel profile was carried out modeling the shear connectors, using contact elements to modeling the interface and after was carried out using TIE constraint. The validation of the numerical model was carried through the correlation between the numerical and experimental results and it was adequate to simulate the experimentally tested beams for both forms of slab profile bonding, especially for the cases where the shear connectors were modeled, because the beams presented lower stiffness and consequently greater proximity of the experimental results.
Employee Performance of Taufiqurrahman Foundation. Case Study the Effect of Compensation, Achievement Motivation, and Working Ethic on Employee Performance of Islamic Integrated Elementary School and Islamic Integrated Junior High School of Taufiqurrahman in Bekasi, West Java, Indonesia
Authors: Kadiman Sukemi
Published: August 2018

The objective of this research is to examine the effect of compensation, achievement motivation, and working ethic towards employee performance of Taufiqurrahman Foundation in Bekasi. The research was conducted using quantitative approach and method of survey. The size of population in this research is 100 employees at Taufiqurrahman Foundation. Reseach sample were selected as 66 employees using sample random sampling technique. The data obtained with questionaires and tests. The analiytical method used in data analyzing is path analysis technique.The result shows that compensation, achievement motivation, and working ethos have positif direct effect toward the employees performance of Taufiqurrahman Foundation in Bekasi. The findings lead to recommendation that in order to build compensation, achievement motivation and working ethic should be considered seriously.
Quality of care in the delivery room: Focusing on respectful maternal care practices
Authors: Mousa Ola , Turingan Oscar M.
Published: August 2018

This study provided a descriptive overview of the care provided in the delivery room focused on respectful maternity care as perceived by women during labor and delivery in a maternity and child health hospital in Egypt. The dimensions examined were those related to services that arepatient-friendly, free of abuse, timely and free of discrimination. A cross-sectional retrospective study was conducted at the postpartum department in Minia University Maternity and Child Health Hospital in Minia, Egypt. Purposive sampling technique was used to recruit participants from a population of postpartum women who delivered their babies in the hospital, received delivery services from 6 hours to 7 days before the study period. The 15-item Respectful Maternal Care (RMC) Scale was used for this study. A total of 580 questionnaires were distributed to the postpartum women in the hospital and 501 were completed and collected giving a retrieval rate of 86.4%. The findings indicated that majority of the postpartum mothers felt that they received friendly care, abuse-free care and a timely care on a moderate degree during childbirth. Generally, the postpartum mothers felt that they received a high degree of discrimination free care during childbirth. Overall, the postpartum mothers in this study experienced moderate degree of respectful maternity care during childbirth. Although the general findings show moderate respectful maternity care, more than fifty percent of the postpartum mothers experienced being shouted at by healthcare workers and more than half of the postpartum mothers claim that they were not given prompt service by the healthcare workers and waiting time is long. These aspects of maternity care need to be improved.
Challenges in Treating Acromioclavicular Separations: Current Concepts
Authors: Cook Jay B. , Krul Kevin P.
Published: August 2018

Injuries to the acromioclavicular joint constitute approximately 3.2% of shoulder injuries. Although the overall goal of treatment continues to be return to activity with a pain-free shoulder, the treatment of acromioclavicular joint separations has been fraught with conflict since the earliest reports in both ancient and modern literature. Accurate diagnosis and classification are important to determine the optimal treatment. Nonsurgical therapy remains the mainstay for treatment of low- and most mid-grade injuries, although recent biomechanical and biokinetic data might suggest that patients are more affected than traditionally thought. High-grade injuries often necessitate surgical intervention, although little consensus exists on the timing or technique. New surgical techniques continue to evolve as more biomechanical data emerge and kinematic understanding improves. Challenges associated with management of this injury abound from diagnosis to reconstruction.
Building Writing Skills in English in Fifth Graders: Analysis of Strategies Based on Literature and Creativity
Authors: Niño Fernando Lopez , Páez Martha Elizabeth Varón
Published: August 2018

The present article is centered on the description and analysis of the process of action-research followed by a group of twenty eight fifth graders of primary level in a public school in Colombia who improved their writing ability in English as a Foreign Language through the application of several creativity writing strategies. Among those strategies we can count the use of acrostics, calligrams, comic strips and posters, connecting children with fiction and real information taken from subjects taught at school. This research was designed with the objective of developing writing skills in a creative way, based on qualitative and quantitative methods by using surveys, checklists, field notes and a final interview to collect data. Findings revealed that writing mistakes were diminished after each one of the sessions application. Additionally, children were motivated to write in English and to assume different positions about topics of their interest from the advantages provided from new knowledge acquired about diverse topics related to their lives.
The Project-Based Flipped Learning Model in Business English Translation Course: Learning, Teaching and Assessment
Authors: Deng Lijun
Published: August 2018

This study designs a project-based flipped learning model for Business English Translation course and tests its efficacy by an empirical study on 65 third-year English major students divided into the experimental class and control class. This study incorporates the learning, teaching and assessment activities of both the students and teachers into a project-based flipped learning model by setting translation projects and dividing the students of the experimental class into a client group and three translator groups in each business translation unit. After one 16-week semester of experiment, this study conducts a post-test, questionnaires and interviews on both the experimental class and control class to test the efficacy of this new flipped learning model. The statistics and facts collected from the above-mentioned research methods suggest that the project-based flipped learning model can significantly enhance the students’ motivation to learn out of class, stimulate their participation in class and raise their self-evaluation on translation competence. Additionally, this study finds that the traditional product-oriented summative assessment model is ineffective for Business English Translation course in a flipped-learning context. Therefore, this study tentatively proposes a process-oriented assessment model that is compatible to the flipped learning methodology so as to build integrated flipped classroom pedagogy with teaching, learning and assessment in a virtuous circle of mutual reinforcing.
Inside The Gates: First-Generation Students Finding Their Way
Authors: Checkoway Barry
Published: August 2018

This paper examines what first-generation students face when coming inside the gates of higher education for the first time, an experience which, without preparation by them and their institution, can disorient them to a level of anxiety which affects their learning. The paper identifies issues arising when they are trying to find their way, such as choosing courses whose content feels foreign, and finding professors who can communicate with them in ways which they understand. It draws upon a review of the literature, and the experiences of the author as a first-generation student and, subsequently, a professor.
Solutions to the Dirac Equation for Manning-Rosen Plus Shifted Deng-Fan Potential and Coulomb-Like Tensor Interaction Using Nikiforov-Uvarov Method
Authors: Louis Hitler , Iserom Ita B. , Odey Magu T. , Ozioma Akakuru U. , Nelson Nzeata-Ibe , Alexander Ikeuba I. , Pigweh Amos I. , Okon Edet C.
Published: August 2018

We solve the Dirac equation for the Manning-Rosen plus shifted Deng-Fan potential including a Coulomb-like tensor potential with arbitrary spin–orbit coupling quantum number κ. In the framework of the spin and pseudospin (pspin) symmetry, we obtain the energy eigenvalue equation and the corresponding eigenfunctions in closed form by using the Nikiforov–Uvarov method. Also Special cases of the potential as been considered and their energy eigen values as well as their corresponding eigen functions are obtained for both relativistic and non-relativistic scope.
First Exploration into the Feasibility of the Construction for Energy Power Corpus
Authors: Tao Shuaicheng , Zhang Qian , Lyu Liangqiu
Published: August 2018

With the rapid development of science and technology, people are more likely to resort to technological products to tackle new problems in life. Associated with some famous theories, corpus, as Professor Mona Baker’s theory suggests, can be utilized in many areas and simplify the process of multilingual transformation. Since it has been rising for a certain period of time, corpus related to energy power has still not been built yet. Despite some potential problems to be solved in the actual exploration, this thesis aims to study on the feasibility of the construction and development for energy power corpus on the basis of the ways, tools, overall design and planning, etc. of the construction so as to make up the lack of data and provide more possibilities in the research field of energy power, and help to broaden the scope of corpus database for ease of more researches and findings in the future study.
Sunn Hemp: A Legume Cover Crop with Potential for the Midwest?
Authors: Durairaj Esther Shekinah , Stute James K.
Published: August 2018

Crops like corn and soybean occupy vast area in the Midwest, USA. When land is left fallow after the harvest of these crops, a number of degradation factors operate and bring about soil erosion, nutrient loss, decreased soil organic carbon, reduced biological activity and increase in weed biomass. Integrating cover crops (CCs) into this system would build benefits that the very system lacks. There are various CCs available, but leguminous CCs allows for reduced application of fertilizer nitrogen and builds the soil fixed atmospheric nitrogen. Winter CCs are restricted in the Midwest because of the short planting window which greatly minimizes the biomass accumulation. Warm season CCs would serve well here. Sunn hemp is one such tropical CC that grows well in temperate conditions too, without producing seeds. It comes with many benefits - including decreased soil erosion, improved soil organic carbon, increase in soil fixed nitrogen, higher biomass that adds organic matter and N to the soil, reduced weed density and weed biomass. The timing and method of termination influences the residue management. Going by the benefits it adds, sunn hemp is a viable warm season CC that can be grown in the Midwest and has great potential in fallows, prevented plant acres, areas of crop failure (planted and failed) and also in areas after the harvest of the short season small grains or processing crops. However, intensive research on sunn hemp is needed in the Midwest which is discussed.
Selection of suitable reference genes for qRT-PCR studies during SE initial dedifferentiation in cotton of different SE capability
Authors: Ping Cao Ai , Nan Shao Dong , Ming Cui Bai , Ying Zheng Yin , jie Sun
Published: August 2018

Analysis of gene expression level by RNA sequencing (RNA-seq ) has a wide range of biological purposes in various species. Real-time fluorescent quantitative PCR (qRT-PCR) evaluated gene expression levels and validated transcriptomic, which will depend on the stably expressed reference genes for normalization of the gene expression level under specific situations. In this study, 15 candidate genes were selected from transcriptome datasets during somatic embryogenesis (SE) initial dedifferentiation in Gossypium hirsutum L. of different SE capability. To evaluate the stability of those genes, geNorm, NormFinder and BestKeeper were used. The results revealed that ENDO4 and 18srRNA could be as appropriate reference genes under all conditions. The stability and reliability of the reference genes were further tested through comparison of qRT-PCR results and RNA-seq data, as well as evaluation of the expression profiles of auxin-responsive protein (AUX22) and ethylene-responsive transcription factor (ERF17). In summary, the results of our study indicate the most suitable reference genes for qRT-PCR during three induction stages in four cotton species.
Negative regulation of conserved RSL class I bHLH transcription factors evolved independently among land plants
Authors: Honkanen Suvi , Thamm Anna , Arteaga-Vazquez Mario A , Dolan Liam
Published: August 2018

Basic helix-loop-helix transcription factors encoded by RSL class I genes control a gene regulatory network that positively regulates the development of filamentous rooting cells – root hairs and rhizoids – in land plants. The GLABRA2 transcription factor negatively regulates these genes in the angiosperm Arabidopsis thaliana. To find negative regulators of RSL class I genes in early diverging land plants we conducted a mutant screen in the liverwort Marchantia polymorpha. This identified FEW RHIZOIDS1 (MpFRH1) microRNA (miRNA) that negatively regulates the RSL class I gene MpRSL1. The miRNA and its mRNA target constitute a feedback mechanism that controls epidermal cell differentiation. MpFRH1 miRNA target sites are conserved among liverwort RSL class I mRNAs but are not present in RSL class I mRNAs of other land plants. These findings indicate that while RSL class I genes are ancient and conserved, independent negative regulatory mechanisms evolved in different lineages during land plant evolution.
Stepwise wiring of the Drosophila olfactory map requires specific Plexin B levels
Authors: Li Jiefu , Guajardo Ricardo , Xu Chuanyun , Wu Bing , Li Hongjie , Li Tongchao , Luginbuhl David J , Xie Xiaojun , Luo Liqun
Published: August 2018

The precise assembly of a neural circuit involves many consecutive steps. The conflict between a limited number of wiring molecules and the complexity of the neural network impels each molecule to execute multiple functions at different steps. Here, we examined the cell-type specific distribution of endogenous levels of axon guidance receptor Plexin B (PlexB) in the developing antennal lobe, the first olfactory processing center in Drosophila. We found that different classes of olfactory receptor neurons (ORNs) express PlexB at different levels in two wiring steps – axonal trajectory choice and subsequent target selection. In line with its temporally distinct patterns, the proper levels of PlexB control both steps in succession. Genetic interactions further revealed that the effect of high-level PlexB is antagonized by its canonical partner Sema2b. Thus, PlexB plays a multifaceted role in instructing the assembly of the Drosophila olfactory circuit through temporally-regulated expression patterns and expression level-dependent effects.
foxr1is a novel maternal-effect gene in fish that is required for early embryonic success
Authors: Cheung Caroline T. , Patinote Amélie , Guiguen Yann , Bobe Julien
Published: August 2018

The family of forkhead box (Fox) transcription factors regulates gonadogenesis and embryogenesis, but the role offoxr1in reproduction is unknown. Evolutionary history offoxr1in vertebrates was examined and the gene was found to exist in most vertebrates, including mammals, ray-finned fish, amphibians, and sauropsids. By quantitative PCR and RNA-seq, we found thatfoxr1had an ovarian-specific expression in zebrafish, a common feature of maternal-effect genes. In addition, it was demonstrated using in situ hybridization thatfoxr1was a maternally-inherited transcript that was highly expressed even in early-stage oocytes and accumulated in the developing eggs during oogenesis. We also analyzed the function offoxr1in female reproduction using a zebrafish CRISPR/cas9 knockout model. It was observed that embryos from thefoxr1-deficient females had a significantly lower survival rate whereby they either failed to undergo cell division or underwent abnormal division that culminated in growth arrest at around the mid-blastula transition and early death. These mutant-derived eggs contained dramatically increased levels ofp21, a cell cycle inhibitor, and reducedrictor, a component of mTOR and regulator of cell survival, which were in line with the observed growth arrest phenotype. Our study shows for the first time thatfoxr1is an essential maternal-effect gene and may be required for proper cell division and survival via the p21 and mTOR pathways. These novel findings will broaden our knowledge on the functions of specific maternal factors stored in the developing egg and the underlying mechanisms that contribute to reproductive success.
Methodology to evaluate the collapse limit state of R/C frames based on the seismic response spectrum
Authors: Matsukawa Kazuto , Maeda Masaki
Published: August 2018

This study proposes a method to evaluate the collapse limit displacement of reinforced concrete buildings based on the seismic response spectrum as a more practical alternative to previous methods based on dynamic analysis. The collapse limit displacement estimated by the proposed method is compared to that obtained by dynamic analysis‐based methods using artificial and observed ground motions. The results of the proposed method correspond well to the dynamic analysis results. However, models with a natural vibration period of 0.2 s exhibited a large dispersion in the results.
A Universal Strategy to Metal Wavy Nanowires for Efficient Electrochemical Water Splitting at pH‐Universal Conditions
Authors: Yang Jian , Ji Yujin , Shao Qi , Zhang Nan , Li Youyong , Huang Xiaoqing
Published: August 2018

While overall water splitting is considered as one of the most efficient approaches for sustainable oxygen and hydrogen generations, the design of robust electrocatalysts that are active and stable for overall water splitting in pH‐universal conditions is still a significant challenge. Herein, a universal strategy for a class of metal wavy nanowires (NWs) for the enhanced electrocatalysis is reported. Benefiting from the structural features of ultrathin nature and numbers of defects, the obtained NWs generally exhibit attractive performances in oxygen evolution reaction (OER) and hydrogen evolution reaction at pH‐universal conditions. More significantly, the optimized Ru O2 NWs‐Ir NWs electrolyzer shows superior performance for overall water splitting with only cell voltages of 1.50 and 1.47 V in 0.05 and 0.5 m H2SO4 and 1.56 and 1.49 V in 0.1and 1 m KOH at 10 mA cm−2, much lower than those of the Ir/C‐Pt/C electrolyzer. First‐principles calculations reveals that the appearance of Ru‐atom point defects on RuO2(200) surface will lower the OER overpotential during which the adsorption free energies of OER intermediates are weakened due to the right‐shift of d‐band center. The RuO2 NWs‐Ir NWs electrolyzer also exhibits excellent durability in long‐term electrolysis, showing exciting prospect for water splitting in different pH electrolytes.
Reparable Superhydrophobic Surface with Hidden Reactivity, Its Photofunctionalization and Photopatterning
Authors: Du Xin , Wang Min , Welle Alexander , Behboodi‐Sadabad Farid , Wang YuLi , Levkin Pavel A. , Gu Zhongze
Published: August 2018

Superhydrophobic (SH) surfaces have held great promise during the last decade because of their diverse potential applications as self‐cleaning surfaces, in microfluidics, microarrays, etc. Recently, reactive SH surfaces combining their liquid‐repellency with the possibility for convenient postfunctionalization and patterning were introduced. However, current concepts for making reactive SH materials have very limited selection of “hydrophobic as well as reactive” groups. Here a novel reparable SH surface with hidden reactivity (SuSHiR) based on photodynamic properties of disulfides is reported. Reactive hydrophobic, SH, as well as superhydrophilic surfaces are fabricated using this method. The method allows the use of diverse end functionalities (reactive or nonreactive, hydrophobic, or hydrophilic), while keeping the same reactive disulfides “hidden” in the middle of the functional surface‐grafted chains. The photoreactivity of the disulfide bond allows for the functionalization and patterning of various molecules through UV irradiation. The obtained SuSHiR exhibits better stability compared to conventional reactive SH surfaces, and the reversibility of the disulfide–disulfide exchange reaction enables reversible patterning as well as photorestoration of damaged functionalities.
Functionalization of Hollow Nanomaterials for Catalytic Applications: Nanoreactor Construction
Authors: Zhu Wei , Chen Zheng , Pan Yuan , Dai Ruoyun , Wu Yue , Zhuang Zhongbin , Wang Dingsheng , Peng Qing , Chen Chen , Li Yadong
Published: August 2018

Hollow nanomaterials have attracted a broad interest in multidisciplinary research due to their unique structure and preeminent properties. Owing to the high specific surface area, well‐defined active site, delimited void space, and tunable mass transfer rate, hollow nanostructures can serve as excellent catalysts, supports, and reactors for a variety of catalytic applications, including photocatalysis, electrocatalysis, heterogeneous catalysis, homogeneous catalysis, etc. Based on state‐of‐the‐art synthetic methods and characterization techniques, researchers focus on the purposeful functionalization of hollow nanomaterials for catalytic mechanism studies and intricate catalytic reactions. Herein, an overview of current reports with respect to the catalysis of functionalized hollow nanomaterials is given, and they are classified into five types of versatile strategies with a top‐down perspective, including textual and composition modification, encapsulation, multishelled construction, anchored single atomic site, and surface molecular engineering. In the detailed case studies, the design and construction of hierarchical hollow catalysts are discussed. Moreover, since hollow structure offers more than two types of spatial‐delimited sites, complicated catalytic reactions are elaborated. In summary, functionalized hollow nanomaterials provide an ideal model for the rational design and development of efficient catalysts.
Recent Advances in Electrochemical CO2‐to‐CO Conversion on Heterogeneous Catalysts
Authors: Zheng Tingting , Jiang Kun , Wang Haotian
Published: August 2018

Electrochemical reduction of carbon dioxide (CO2) to fuels and chemicals provides a promising solution for renewable energy storage and utilization. Among the many possible reaction pathways, CO2 conversion to carbon monoxide (CO) is the first step in the synthesis of more complex carbon‐based fuels and feedstocks, and holds great significance for the chemical industry. Herein, recent advances in heterogeneous catalysts for selective CO evolution from electrochemical reduction of CO2 are described. With Au catalysts as a paradigm, principles for catalyst design including size, morphology, and grain boundary densities tuning, surface modifications, as well as metal‐support interaction are comprehensively summarized, which shed light on the development of other transition metal catalysts targeting efficient CO2‐to‐CO conversion. In addition, recently emerged novel materials including transition metal single‐atom catalysts, which present significantly different catalytic behaviors compared to their bulk counterparts and thus open up many unexpected opportunities, are summarized. Furthermore, the technical aspects with respect to large‐scale production of CO are presented, focusing on the full‐cell design and implementation. Finally, short comments related to the future direction of real‐word CO2 electrolysis for CO supply are provided in terms of catalyst optimization and technical breakthrough.
Highly Efficient Photosensitizers with Far‐Red/Near‐Infrared Aggregation‐Induced Emission for In Vitro and In Vivo Cancer Theranostics
Authors: Wang Dong , Lee Michelle M. S. , Shan Guogang , Kwok Ryan T. K. , Lam Jacky W. Y. , Su Huifang , Cai Yuchen , Tang Ben Zhong
Published: August 2018

Fluorescence‐imaging‐guided photodynamic therapy has emerged as a promising protocol for cancer theranostics. However, facile preparation of such a theranostic material for simultaneously achieving bright emission with long wavelength, high‐performance reactive oxygen species (ROS) generation, and good targeting‐specificity of cancer cells, is highly desirable but remains challenging. In this study, a novel type of far‐red/near‐infrared‐emissive fluorescent molecules with aggregation‐induced emission (AIE) characteristics is synthesized through a few steps reaction. These AIE luminogens (AIEgens) possess simple structures, excellent photostabilities, large Stokes shifts, bright emission, and good biocompatibilities. Meanwhile, their ROS generation is extremely efficient with up to 90.7% of ROS quantum yield, which is far superior to that of some popularly used photosensitizers. Importantly, these AIEgens are able to selectively target and ablate cancer cells over normal cells without the aid of any extra targeting ligands. Rather than using laser light, one of the presented AIEgens (MeTTPy) shows a remarkable tumor‐targeting photodynamic therapeutic effect by using an ultralow‐power lamp light (18 mW cm−2). This study thus not only extends the applications scope of AIEgens, but also offers useful insights into designing a new generation of cancer theranostics.
Artificial Soft Elastic Media with Periodic Hard Inclusions for Tailoring Strain‐Sensitive Thin‐Film Responses
Authors: Byun Junghwan , Chung Seungjun , Hong Yongtaek
Published: August 2018

Engineering the coupling behavior between a functional thin film and a soft substrate provides an attractive pathway for controlling various properties of thin‐film materials. However, existing studies mostly rely on uniform deformation of the substrate, and the effect of well‐regulated and nonuniform strain distributions on strain‐sensitive thin‐film responses still remains elusive. Herein, artificially strain‐regulated elastic media are presented as a novel platform for tailoring strain‐sensitive thin‐film responses. The proposed artificial soft elastic media are composed of embedded arrays of inkjet‐printed polymeric strain modulators that exhibit a high modulus contrast with respect to that of the soft matrix. This strain‐modulating lattice induces spatially regulated strain distributions based on localized strain‐coupling. Controlling the structural parameters and lattice configurations of the media leads to spatial modulation of the microscopically localized as well as macroscopically accumulated strain profiles. Uniform thin films coupled to these media undergo artificially tailored deformation through lattice‐like strain‐coupled pathways. The resulting phenomena yield programmable strain‐sensitive responses such as spatial arrangement of ternary‐state surface wrinkles and stepwise tuning of piezoresistive responses. This work will open a new avenue for addressing the issue of controlling strain‐sensitive thin‐film properties through structural engineering of artificial soft elastic media.
Functional Scanning Force Microscopy for Energy Nanodevices
Authors: Chen Xi , Lai Junqi , Shen Yanbin , Chen Qi , Chen Liwei
Published: August 2018

Energy nanodevices, including energy conversion and energy storage devices, have become a major cross‐disciplinary field in recent years. These devices feature long‐range electron and ion transport coupled with chemical transformation, which call for novel characterization tools to understand device operation mechanisms. In this context, recent developments in functional scanning force microscopy techniques and their application in thin‐film photovoltaic devices and lithium batteries are reviewed. The advantages of scanning force microscopy, such as high spatial resolution, multimodal imaging, and the possibility of in situ and in operando imaging, are emphasized. The survey indicates that functional scanning force microscopy is making significant contributions in understanding materials and interfaces in energy nanodevices.
Visible‐to‐NIR Photon Harvesting: Progressive Engineering of Catalysts for Solar‐Powered Environmental Purification and Fuel Production
Authors: Yang Min‐Quan , Gao Minmin , Hong Minghui , Ho Ghim Wei
Published: August 2018

Utilization of diffusive solar energy through photocatalytic processes for environmental purification and fuel production has long been pursued. However, efficient capture of visible–near‐infrared (NIR) photons, especially for those with wavelengths longer than 600 nm, is a demanding quest in photocatalysis owing to their relatively low energy. In recent years, benefiting from the advances in photoactive material design, photocatalytic reaction system optimization, and new emerging mechanisms for long‐wavelength photon activation, increasing numbers of studies on the harnessing of visible–NIR light for solar‐to‐chemical energy conversion have been reported. Here, the aim is to comprehensively summarize the progress in this area. The main strategies of the long‐wavelength visible–NIR photon capture and the explicitly engineered material systems, i.e., narrow optical gap, photosensitizers, upconversion, and photothermal materials, are elaborated. In addition, the advances in long‐wavelength light‐driven photo‐ and photothermal‐catalytic environmental remediation and fuel production are discussed. It is anticipated that this review presents the forefront achievements in visible–NIR photon capture and at the same time promotes the development of novel visible–NIR photon harnessing catalysts toward efficient solar energy utilization.
“Snowing” Graphene using Microwave Ovens
Authors: Sun Yangyong , Yang Liangwei , Xia Kailun , Liu Haizhou , Han Dong , Zhang Yingying , Zhang Jin
Published: August 2018

Developing a simple and industrially scalable method to produce graphene with high quality and low cost will determine graphene's future. The two conventional approaches, chemical vapor deposition and liquid‐phase exfoliation, require either costly substrates with limited production rate or complicated post treatment with limited quality, astricting their development. Herein, an extremely simple process is presented for synthesizing high quality graphene at low‐cost in the gas phase, similar to “snowing,” which is catalyst‐free, substrate‐free, and scalable. This is achieved by utilizing corona discharge of SiO2/Si in an ordinary household microwave oven at ambient pressure. High quality graphene flakes can “snow” on any substrate, with thin‐flakes even down to the monolayer. In particular, a high yield of ≈6.28% or a rate of up to ≈0.11 g h−1 can be achieved in a conventional microwave oven. It is demonstrated that the snowing process produces foam‐like, fluffy, 3D macroscopic architectures, which are further used in strain sensors for achieving high sensitivity (average gauge factor ≈ 171.06) and large workable strain range (0%–110%) simultaneously. It is foreseen that this facile and scalable strategy can be extended for “snowing” other functional 2D materials, benefiting their low‐cost production and wide applications.
Revealing Driving Forces in Quantum Dot Supercrystal Assembly
Authors: Marino Emanuele , Kodger Thomas E. , Wegdam Gerard H. , Schall Peter
Published: August 2018

The assembly of semiconductor nanoparticles, quantum dots (QDs), into dense crystalline nanostructures holds great promise for future optoelectronic devices. However, knowledge of the sub‐nanometer scale driving forces underlying the kinetic processes of nucleation, growth, and final densification during QD assembly remains poor. Emulsion‐templated assembly has recently been shown to provide good control over the bulk condensation of QDs into highly ordered 3D supercrystals. Here, emulsion‐templated assembly is combined with in situ small‐angle X‐ray scattering to obtain direct insight into the nanoscale interactions underlying the nucleation, growth, and densification of QD supercrystals. At the point of supercrystal nucleation, nanoparticles undergo a hard‐sphere‐like crystallization into a hexagonal‐close‐packed lattice, slowly transforming into a face‐centered‐cubic lattice. The ligands play a crucial role in balancing steric repulsion against attractive van der Waals forces to mediate the initial equilibrium assembly, but cause the QDs to be progressively destabilized upon densification. The rich detail of this kinetic study elucidates the assembly and thermodynamic properties that define QD supercrystal fabrication approaching single‐crystal quality, paving the way toward their use in optoelectronic devices.
Edge‐Epitaxial Growth of 2D NbS2‐WS2 Lateral Metal‐Semiconductor Heterostructures
Authors: Zhang Yu , Yin Lei , Chu Junwei , Shifa Tofik Ahmed , Xia Jing , Wang Feng , Wen Yao , Zhan Xueying , Wang Zhenxing , He Jun
Published: August 2018

2D metal‐semiconductor heterostructures based on transition metal dichalcogenides (TMDs) are considered as intriguing building blocks for various fields, such as contact engineering and high‐frequency devices. Although, a series of p–n junctions utilizing semiconducting TMDs have been constructed hitherto, the realization of such a scheme using 2D metallic analogs has not been reported. Here, the synthesis of uniform monolayer metallic NbS2 on sapphire substrate with domain size reaching to a millimeter scale via a facile chemical vapor deposition (CVD) route is demonstrated. More importantly, the epitaxial growth of NbS2‐WS2 lateral metal‐semiconductor heterostructures via a “two‐step” CVD method is realized. Both the lateral and vertical NbS2‐WS2 heterostructures are achieved here. Transmission electron microscopy studies reveal a clear chemical modulation with distinct interfaces. Raman and photoluminescence maps confirm the precisely controlled spatial modulation of the as‐grown NbS2‐WS2 heterostructures. The existence of the NbS2‐WS2 heterostructures is further manifested by electrical transport measurements. This work broadens the horizon of the in situ synthesis of TMD‐based heterostructures and enlightens the possibility of applications based on 2D metal‐semiconductor heterostructures.
Wet‐to‐Dry Hybrid Spinning of Graphene Fiber Inspired by Spider Silk Production Mechanisms
Authors: Lee Kyueui , Do Minjae , Seo Young Chang , Lee Haeshin
Published: August 2018

This study describes a graphene oxide (GO) fiber spinning method that produces a nearly 100% yield for converting a GO suspension into fibers. The fiber formation method is inspired by the spider silk spinning strategy. The dissolved silk protein, spidroin (wet state), is extruded and shear‐thinned through a posterior spinneret, exposing the silk to a dry state for curing. The wet‐to‐dry conversion in a spider spinneret enables nearly all the fiber precursor, spidroin, to be fabricated into a silk fiber with no loss of protein. Inspired by the process, a “wet‐to‐dry” hybrid spinning of GO is developed in which nearly all GOs are converted into fiber. At the liquid–liquid interface of two droplets containing GO and polyethyleneimine, the two oppositely charged components bind to each other in the wet state. Subsequently, one component touches and pulls the interfacial mixing point of the two droplets, forming a vertical, thin liquid column in which GO complexes experience shear force and directionally align into a thin fiber. Compared to existing wet‐spinning methods, this wet‐to‐dry method is highly energy efficient in terms of the simple procedure, lack of waste chemicals, and nearly 100% conversion of GO precursors.
One‐Pot Synthesis of Icosahedral PdPtNi/C Twin Crystal Catalyst with High Activity toward Oxygen Reduction Reaction
Authors: Cao Fengting , Liu Tao , Si Wenyan , Li Xichao , Sun Shimei , Sun Xiaolin , Niu Quanhai , Ohsaka Takeo , Wu Jianfei
Published: August 2018

Pt and Pt‐based alloys are still the mainstream electrocatalysts for oxygen reduction reaction (ORR) so far, which is an important process for fuel cell. Herein, for the first time ternary icosahedral nanocrystals supported on carbon PdPtNi/C are constructed by a facile one‐pot approach and are characterized by X‐ray diffraction, transmission electron microscopy, and X‐ray photoelectron spectroscopy. The electrocatalytic performance of the as‐prepared catalyst for ORR is evaluated in acid electrolyte and compared with the state‐of‐the‐art commercial Pt/C catalyst at identical condition. The icosahedral structure with 20 exposed {111} facets and twin boundaries are the distinguishing features of the PdPtNi/C nanoparticles, which enable them to be more active. The compressive strain effect and electronic interaction (ligand effect) of Pd, Pt, and Ni elements are also responsible for the excellent performance of the catalyst: the higher onset potential of ORR than that of commercial Pt/C, the outstanding specific activity and mass activity, which is about 9.59 and 5.40 times higher than those of commercial Pt/C at 0.90 VRHE, respectively, while 5.39 and 4.75 times higher at 0.85 VRHE, respectively. These results can promote the practical application of Pt‐based catalyst and thus accelerate the widespread commercialization of fuel cell technologies.
Compliance‐Mediated Topographic Oscillation of Polarized Light Triggered Liquid Crystal Coating
Authors: Hendrikx Matthew , Sırma Burcu , Schenning Albertus P. H. J. , Liu Danqing , Broer Dirk J.
Published: August 2018

The ability to induce oscillating surface topographies in light‐responsive liquid crystal networks on‐demand by light is interesting for applications in soft robotics, self‐cleaning surfaces, and haptics. However, the common height of these surface features is in the range of tens of nanometer, which limits their applications. Here a photoresponsive liquid crystal network coating with a patterned director motive exhibiting surface features that oscillate dynamically when addressed by light with modulated polarization is reported. By utilizing a compliant intermediate layer, the surface topographies increase with a factor 10, from roughly 70–100 nm to 1 µm. This increase in topography height is accompanied by a superimposed dynamic oscillation with an amplitude of ≈100 nm. These values can be translated to a 16.7% average static strain with 3.3% oscillations with respect to the coating thickness. Moreover, utilizing the complying support increases the maximum rotation speeds with an in‐phase response from 2.5 up to 25° s−1. However, at this maximized rotation speed the oscillation amplitude decreases to about half of the initial value.
Fabricating 3D Structures by Combining 2D Printing and Relaxation of Strain
Authors: Cafferty Brian J. , Campbell Victoria E. , Rothemund Philipp , Preston Daniel J. , Ainla Alar , Fulleringer Nicolas , Diaz Alina C. , Fuentes Alberto E. , Sameoto Dan , Lewis Jennifer A. , Whitesides George M.
Published: August 2018

This paper describes the fabrication of elastomeric three‐dimensional (3D) structures starting from two‐dimensional (2D) sheets using a combination of direct‐ink printing and relaxation of strain. These structures are fabricated in a two‐step process: first, elastomeric inks are deposited as 2D structures on a stretched elastomeric sheet, and second, after curing of the elastomeric inks, relaxation of strain in the 2D sheet causes it to deform into a 3D shape. To predict bending of elastomeric objects fabricated with this technique, a simple mechanical model is developed. The strategy of using initially 2D materials to fabricate 3D structures offers four new features that complement digital fabrication techniques. (i) It provides a simple route to create shapes with complex curves, suspended features, and internal cavities. (ii) It is a faster method of fabricating some types of shapes than “conventional” 3D printing, because the features are printed in 2D. (iii) It forms surfaces that can be both smoother, and structured in a way that is not compatible with layer‐by‐layer processing. (iv) It forms structures that can be deformed reversibly after fabrication by reapplying strain. This paper demonstrates these features by fabrication of helices, structures inspired by cubes and tables, “pop‐up” structures, and soft grippers.
Polycyclic Indolines by an Acid‐Mediated Intramolecular Dearomative Strategy: Reversing Indole Reactivity in the Pictet‐Spengler‐Type Reaction
Authors: Ciccolini Cecilia , Mari Michele , Lucarini Simone , Mantellini Fabio , Piersanti Giovanni , Favi Gianfranco
Published: August 2018

Indoline‐fused polycycles were synthesized through a TFA‐promoted intramolecular dearomative cyclization of indole‐tethered pyrroles. Mechanistically, the strategic carbon‐carbon bond formation is hypothesized to proceed via a Pictet‐Spengler‐type reaction wherein a reversal of conventional indole reactivity of tryptamine derivatives occurs. The synthetic versatility of this operationally simple, atom‐economic approach is demonstrated in the preparation of the pyrido[1,2‐a:3,4‐b′]diindole core of natural product homofascaplysin C.

magnified image
Recent Advances in RNA Therapeutics and RNA Delivery Systems Based on Nanoparticles
Authors: Shin Hojeong , Park Se‐Jin , Yim Yeajee , Kim Jungho , Choi Chulwon , Won Cheolhee , Min Dal‐Hee
Published: August 2018

Recently, there have been significant advances in the field of RNA‐based therapeutics harnessing exogenous RNAs including small interfering RNA (siRNA), microRNA (miRNA) mimics, and in vitro transcribed (IVT) mRNAs. RNA‐based therapeutics are one of the most attractive classes of drugs for treating a variety of diseases. In principle, RNA‐based therapeutics offer numerous advantages compared to the conventional small‐molecule‐based therapies. However, there are several drawbacks to overcome in the application of RNA‐based therapeutics, including the instability of RNAs and presence of various biological barriers. In the past decades, there have been various attempts to overcome these key challenges. Here, the authors present an overview of RNA‐based therapeutics and recent advances including their delivery systems and clinical applications. In addition, the current challenges of RNA‐based drugs are discussed, followed by perspectives with regard to the development of these promising drug candidates to elicit successful clinical outcomes.