bluuebunny/crossref_metadata_2025 huggingface dataset:
Os Objectos de Aprendizagem e a Construção da Literacia Digital no Ensino à Distância
Authors: De Moçambique Universidade Católica
Published: November 2024

O presente artigo tem por finalidade apresentar uma breve reflexão sobre literacia digital nos  estudantes do Ensino à  Distância, online, (EaD) do Centro de Recursos de Maputo, da Universidade Católica de Moçambique.  O seu principal objetivo é perceber como se realiza  a literacia digital nos estudantes dos cursos online e como esta é compreendida pelos próprios.  É uma pesquisa de carácter descritivo, de natureza qualitativa,  que procura compreender os fenómenos no seu ambiente natural, sem qualquer tipo de manipulação. É do tipo bibliográfico e documental,  elaborada a partir de livros já publicados e documentos emanados pelo governo Moçambicano, que elucidam sobre as principais políticas das TIC na EaD. De forma geral, foi possível perceber através deste estudo que, educar para a tecnoliteracia, é um dos maiores desafios da educação no  século XXI,  dado que se vive numa sociedade que tem vindo paulatinamente a migrar,do meio geográfico (físico) para o meio virtual oferecido pela Internet, o que mudou radicalmente a dinâmica das relações que envolvem uma troca de informação. A internet e a comunicação em rede trouxeram, não só uma nova linguagem,  como novas formas de escrita e leitura, em textos electrónicos mediados pelas TIC.
A Comunicação Interna como Estratégia de Reforço da Identidade e Cultura das Organizações
Authors: De Moçambique Universidade Católica
Published: November 2024

A partir da Direcção Executiva CFM – Norte e com oobjectivo de analisar as estratégias de comunicação interna utilizadas, opresente trabalho aborda a Comunicação Interna como Estratégia de Reforço da Identidade e Cultura das Organizações. No que diz respeito à classificação, a pesquisa segue uma abordagem mista, predominantemente qualitativa de base interpretativa. Os instrumentos utilizados para a recolha de dados, isto é, os dados qualitativos e quantitativos, foram obtidos através de entrevistas (semi-estruturadas), inquéritos por questionário (do tipo Likert) e grupos de foco. A pesquisa evidenciou que a comunicação interna tem vindo a ganhar espaço no que se refere ao reforço da identidade e cultura da organização, bem como influencia na reputação da imagem corporativa. Ficou patente que os colaboradores conhecem os meios pelos quais a comunicação é partilhada e os níveis de satisfação a respeito da aplicação. Porém, relatam que devem ocorrer melhoramentos, principalmente, em relação à sua fluidez.
POPULIST POLITICS IN PAKISTAN: A CASE STUDY OF PAKISTAN THREEK -E- INSAF (PTI) FROM 2018-2023
Authors: InayatUllah  , Taskeen Ahmad  , Wasif Khan  , Abbas Ur Rahman  , Faisal Zaman  , Mairajul Hamid
Published: November 2024

Populism, although not a new political ideology, has witnessed a significant resurgence since the late 20th century. Emerging initially among Southern sharecroppers and tenant farmers in the United States during the 1880s, populism has since manifested globally, characterized by its opposition to elites and its appeal to the "common people." This thesis explores the nature of populism, its ideological foundations, and its impact on contemporary politics, with a particular focus on Pakistan's political landscape. The study critically examines the populist strategies of Pakistan Tehreek-e-Insaf (PTI) and its leader Imran Khan, assessing their socio-political and economic consequences from 2018 to 2023. By distinguishing between populist and non-populist politics in Pakistan, this research provides a comprehensive analysis of PTI's rise and its implications for democracy and governance in the region. The analysis reveals the intricate dynamics between populist rhetoric and policy, and their effects on the economic and sociopolitical fabric of Pakistan. Key findings indicate that PTI's populist approach has significantly reshaped political discourse and governance structures, promoting a narrative that pits the "pure people" against the "corrupt elite." The thesis also highlights the broader implications of populism for democratic practices, suggesting that while populism can invigorate political engagement and address genuine grievances, it also poses challenges to pluralism and institutional stability. Ultimately, this research contributes to a deeper understanding of populism in the Pakistani context, offering valuable insights into its potential trajectories and the critical balance required to sustain democratic values amidst rising populist sentiments.
Removing Popular Faces in Curve Arrangements
Authors: De Nooijer Phoebe , Terziadis Soeren , Weinberger Alexandra , Masárová Zuzana , Mchedlidze Tamara , Löffler Maarten , Rote Günter
Published: November 2024

A face in a curve arrangement is called popular if it is bounded by the same curve multiple times. Motivated by the automatic generation of curved nonogram puzzles, we investigate possibilities to eliminate the popular faces in an arrangement by inserting a single additional curve. This turns out to be NP-hard; however, it becomes tractable when the number of popular faces is small: We present a randomized FPT-time algorithm where the parameter is the number of popular faces.
Analysis of the possibilities of determining location in a Wi-Fi network using neural network algorithms
Authors: Lizneva Yuliya Sergeevna , Kostyukovich Anatoliy Egorovich , Kokoreva Elena Viktorovna
Published: November 2024

Indoor positioning on a Wi-Fi network belongs to a class of tasks in which the dependence of output characteristics on input variables is influenced by many parameters and external factors. When solving such problems, it is necessary to take into account that in determining the location, it is of significant interest not only to determine the static coordinates of an object, but also to predict the vector of its movements. In the case where the location of an object is determined only by the level of signal power received from several access points on a Wi-Fi network, the use of signal attenuation models that take into account the conditions of propagation of radio waves indoors is difficult due to the need for reliable information about the material of ceilings, floors and ceilings, the presence of fixed and mobile shading objects, etc. Since the electromagnetic environment inside the room varies depending on many factors, the above-mentioned models have to be adjusted to these changes. Since finding patterns in a large amount of data requires non-standard algorithms, artificial neural networks can be used to solve the positioning problem. It is important to choose a neural network architecture that can take into account changes in the signal strength received by a mobile device from Wi-Fi access points. Before training a neural network, statistical data is preprocessed. For example, abnormal cases are excluded from the machine learning dataset when the device detects a signal from less than three access points at one measuring point. As a result of the analysis of statistical data, it was found that the same distance between the measuring points leads to the fact that the neural network incorrectly determines the location of the object. The paper shows that in order to increase the accuracy of positioning the location in conditions of complex radio placement, when compiling radio maps, it is necessary to determine the optimal varying distances between measuring points. The conducted experimental studies, taking into account the proposed approach to optimizing the distances between measuring points, prove that the accuracy of location determination in the vast majority of measuring points reaches 100%.
A review on ecology, distribution, phytochemistry, and pharmacological properties of the medicinally important plant Pterocarpus santalinus L. (Red sanders)
Authors: Keshavamurthy M. , Devi N. Gayathri , Manjula A. C. , Shubha K. S. , Deepashree C. L. , Janani P. , Archana R. M.
Published: November 2024

Pterocarpus santalinus L., commonly known as Red sanders, belongs to the family Fabaceae. The plant is well-known for its distinctive wood, which has a stunning color, a delicate appearance, and exceptional technical features. The natural dye santalin, which is produced by the red wood, is used to color foodstuffs and pharmaceutical formulations. The decoction made from the heartwood is given numerous therapeutic characteristics in the ancient system of medicine. It has been used to induce vomiting as well as treat ulcers, mental disorders, and eye illnesses. It is known that the heartwood of Red sander trees has diaphoretic, aphrodisiac, anti-pyretic, anti-inflammatory, anti-helminthic, hemorrhage, and dysentery-preventing properties. Additionally, it has served as a cooling agent. It has been claimed that an ethanol extract of stem bark has anti-hyperglycemic properties. Various studies on the phytochemistry of stem bark extracts in ethanol extracts showed the presence of tannins, phenols, alkaloids, glycosides, flavonoids, and triterpenoids, as well as saponins. Isoflavone glucosides and two anti-tumor lignans, savinin, and calocedrin, are found in the heart wood. However, despite numerous claims of pharmacological activity, the species has not been thoroughly investigated. The current article emphasizes the phytochemistry, pharmacological potential, and applications of P. santalinus.
Component control and additive engineering of all-inorganic perovskite films and carbon-based solar cells under ambient air environment
Authors: Zhong Ting-Ting , Hao Hui-Ying ,   School of Materials Science and Engineering, Tianjin Chengjian University, Tianjin 300384, China,   Tianjin Key Laboratory of Building Green Functional Materials, Tianjin 300384, China,   School of Science, China University of Geosciences (Beijing), Beijing 100083, China
Published: November 2024

The new all-inorganic CsPbX3 perovskite material is expected to be used as an absorbing layer to prepare solar cells for efficient and stable commercial devices. However, the problems of high cost and poor stability, caused by precious metal electrodes and hole transport materials, urgently need solving. Therefore, carbon-based perovskite solar cells (C-PSCs) based on the HTL-free all-inorganic system have attracted widespread attention. This work adopts a strategy of finely regulating the ratio of I to Br in X-site of perovskite. Using the one-step anti-solvent method, CsPbIxBr3–x films and HTL-free C-PSCs are prepared under ambient air condition. By comparing their light absorption characteristics, carrier transport, and corresponding optoelectronic properties, a balance point between efficiency and stability is found. Finally, HTL-free C-PSCs achieve an optimal efficiency of 10.10% and can be stably prepared under ambient air conditions. In order to further improve the performance of the corresponding devices, phenylethylammonium bromide (PEABr) is introduced into the perovskite, and the crystallinity, carrier transport, defect situation, and corresponding optoelectronic properties of perovskite films and devices are compared under different conditions. Ultimately, the perovskite film treated with PEABr reaches better crystallinity and lower defect density, while generating a small amount of two-dimensional perovskite which can passivate the perovskite film and suppress non-radiative recombination of charge carriers. After appropriate PEABr treatment, the photoelectric conversion efficiency (PCE) of the device is significantly enhanced, increasing from 10.18% of the optimal device in the control group to 12.61%. Thus, this method provides an optimal approach for preparing efficient and low-cost HTL-free C-PSCs under ambient air environments.
Characterizing the Spatial Distribution of Dendritic RNA at Single Molecule Resolution
Authors: Kim Jihoon , Rosario Jean G , Mendoza Eric , Kuang Da , Kim Junhyong
Published: November 2024

Neurons possess highly polarized morphology that require intricate molecular organization, partly facilitated by RNA localization. By localizing specific mRNA, neurons can modulate synaptic features through local translation and subsequent modification of protein concentrations in response to stimuli. The resulting activity-dependent modifications are essential for synaptic plasticity, and consequently, fundamental for learning and memory. Consequently, high-resolution characterization of the spatial distribution of dendritic transcripts and the spatial relationship across transcripts is critical for understanding the pathways and mechanisms underlying synaptic plasticity. In this study, we characterize the spatial distribution of six previously uncharacterized genes (
Adap2
,
Colec12
,
Dtx3L
,
Kif5c
,
Nsmf
,
Pde2a
) within the dendrites at a sub-micrometer scale, using single-molecule fluorescence in situ hybridization (smFISH). We found that spatial distributions of dendritically localized mRNA depended on both dendrite morphology and gene identity that cannot be recreated by diffusion alone, suggesting involvement of active mechanisms. Furthermore, our analysis reveals that dendritically localized mRNAs are likely co-transported and organized into clusters at larger spatial scales, indicating a more complex organization of mRNA within dendrites.
Inhibition of the Notch signal transducer CSL by Pkc53E-mediated phosphorylation to fend off parasitic immune challenge in Drosophila
Authors: Deichsel Sebastian , Frankenreiter Lisa , Fechner Johannes , Gahr Bernd M , Zimmermann Mirjam , Mastel Helena , Preis Irina , Preiss Anette , Nagel Anja C
Published: November 2024

Notch signalling activity regulates hematopoiesis in Drosophila and vertebrates alike. Parasitoid wasp infestation of Drosophila larvae, however, requires a timely downregulation of Notch activity to allow the formation of encapsulation-active blood cells. Here, we show that the Drosophila CSL transcription factor Suppressor of Hairless [Su(H)] is phosphorylated at Serine 269 in response to parasitoid wasp infestation. As this phosphorylation interferes with the DNA binding of Su(H), it reversibly precludes its activity. Accordingly, phospho-deficient Su(H)S269A mutants are immune-compromised. A screen for kinases involved in Su(H) phosphorylation identified Pkc53E, required for normal hematopoiesis as well as for parasitoid immune response. Genetic and molecular interactions support the specificity of the Su(H)-Pkc53E relationship. Moreover, phorbol ester treatment inhibits Su(H) activity in vivo and in human cell culture. We conclude that Pkc53E targets Su(H) during parasitic wasp infestation, thereby remodelling the blood cell population required for wasp egg encapsulation.
Circadian regulation of endoplasmic reticulum calcium response in cultured mouse astrocytes
Authors: Ryu Ji Eun , Shim Kyu-Won , Roh Hyun Woong , Park Minsung , Lee Jae-Hyung , Kim Eun Young
Published: November 2024

The circadian clock, an internal time-keeping system orchestrates 24-hour rhythms in physiology and behavior by regulating rhythmic transcription in cells. Astrocytes, the most abundant glial cells, play crucial roles in central nervous system (CNS) functions, but the impact of the circadian clock on astrocyte functions remains largely unexplored. In this study, we identified 412 circadian rhythmic transcripts in cultured mouse cortical astrocytes through RNA sequencing. Gene Ontology analysis indicated that genes involved in Ca
2+
homeostasis are under circadian control. Notably,
Herpud1
(
Herp
) exhibited robust circadian rhythmicity at both mRNA and protein levels, a rhythm disrupted in astrocytes lacking the circadian transcription factor, BMAL1. HERP regulated endoplasmic reticulum (ER) Ca
2+
release by modulating the degradation of inositol 1,4,5-trisphosphate receptors (ITPRs). ATP-stimulated ER Ca
2+
release varied with the circadian phase, being more pronounced at subjective night phase, likely due to the rhythmic expression of ITPR2. Correspondingly, ATP-stimulated cytosolic Ca
2+
increases were heightened at the subjective night phase. This rhythmic ER Ca
2+
response led to circadian phase-dependent variations in the phosphorylation of Connexin 43 (Ser368) and gap junctional communication. Given the role of gap junction channel (GJC) in propagating Ca
2+
signals, we suggest that this circadian regulation of ER Ca
2+
responses could affect astrocytic modulation of synaptic activity according to the time of day. Overall, our study enhances the understanding of how the circadian clock influences astrocyte function in the CNS, shedding light on their potential role in daily variations of brain activity and health.
CuAl-LDH Modified with Filamentous Macroalgae for Anionic Dyes Removal: A Study on Selectivity, Adsorption Efficiency, and Regeneration
Authors: Wijaya Alfan , Hanum Laila , Melwita Elda , Lesbani Aldes
Published: November 2024

Continuous modifications of Layered Double Hydroxides (LDH) materials are essential to enhance their structural stability and improve their capacity for pollutant adsorption, addressing the need for more effective remediation strategies in environmental applications. This research study has proposed the preparation of CuAl-LDH supported filamentous macroalgae of Spirogyra sp. (CuAl-LDH/SA) via coprecipitation and hydrothermal methods. The prepared CuAl-LDH/SA composites were investigated for the adsorption of direct yellow 12 (DY) and remazol red (RR) dyes in batch mode experiments. The structure and morphology of the prepared CuAl-LDH/SA were identified by X-ray Diffraction (XRD), Fourier Transform Infra Red (FT-IR), (Brunauer-Emmett-Teller) BET surface area, Thermogravimetry / Differential Thermal Analyzer (TG/DTA), and Scanning Electron Microscope (SEM). For the adsorption process, the effects of initial pH, contact time, initial concentration, temperature, adsorption selectivity, and adsorbent regeneration, as well as kinetics, isotherms, and thermodynamics were studied. The adsorption selectivity test resulted in the RR dye being more selective compared to DY. The maximum capacities for RR adsorption were 72.464 mg/g (pH = 2, 150 min, 303 K). CuAl-LDH/SA can be regenerated for 4 cycles with a percent removal of 29.32%. The adsorption process followed the intraparticle diffusion kinetics model and Langmuir isotherm. Thermodynamic studies showed that the adsorption of RR using CuAl-LDH/SA was endothermic and spontaneous. The results of this study indicate that CuAl-LDH/SA composite material shows potential material in the removal of anionic dyes from aqueous solutions. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
Transfer learning for high‐precision trajectory tracking through adaptive feedback and iterative learning
Authors: Pereida Karime , Kooijman Dave , Duivenvoorden Rikky R. P. R. , Schoellig Angela P.
Published: June 2018

Robust and adaptive control strategies are needed when robots or automated systems are introduced to unknown and dynamic environments where they are required to cope with disturbances, unmodeled dynamics, and parametric uncertainties. In this paper, we demonstrate the capabilities of a combined
adaptive control and iterative learning control (ILC) framework to achieve high‐precision trajectory tracking in the presence of unknown and changing disturbances. The
adaptive controller makes the system behave close to a reference model; however, it does not guarantee that perfect trajectory tracking is achieved, while ILC improves trajectory tracking performance based on previous iterations. The combined framework in this paper uses
adaptive control as an underlying controller that achieves a robust and repeatable behavior, while the ILC acts as a high‐level adaptation scheme that mainly compensates for systematic tracking errors. We illustrate that this framework enables transfer learning between dynamically different systems, where learned experience of one system can be shown to be beneficial for another different system. Experimental results with two different quadrotors show the superior performance of the combined
‐ILC framework compared with approaches using ILC with an underlying proportional‐derivative controller or proportional‐integral‐derivative controller. Results highlight that our
‐ILC framework can achieve high‐precision trajectory tracking when unknown and changing disturbances are present and can achieve transfer of learned experience between dynamically different systems. Moreover, our approach is able to achieve precise trajectory tracking in the first attempt when the initial input is generated based on the reference model of the adaptive controller.
First Principles Study of Mechanical Properties and Electronic Structures of Vanadium‐Doped TiC and TiN
Authors: Sun Shuting , Liu Yangzhen , Fu Hanguang , Guo Xingye , Ma Shengqiang , Lin Jian , Guo Gencai , Lei Yongping , Wang Ruzhi
Published: June 2018

The mechanical properties and electronic structures of TiC and TiN with different doping ratio of vanadium (V) are studied in this work using the first principles calculations. The simulation results show that Ti1−xVxN has lower formation energy than Ti1−xVxC, suggesting higher chemical stability of Ti1−xVxN. Ti0.25V0.75C and TiN show larger hardness than other Ti1−xVxC and Ti1−xVxN compounds. The anisotropic Young's modulus of Ti1−xVxC and Ti1−xVxN models are plotted in 3D surface constructions, and VN exhibited the strongest anisotropy. The uniaxial tensile simulation of Ti1−xVxC and Ti1−xVxN are conducted along [111] direction. The tensile strength of Ti1−xVxN is stronger than Ti1−xVxC. The tensile strength increases with the increasing of V‐doping ratio. Furthermore, the electronic structures of Ti1−xVxC and Ti1−xVxN are estimated. The modeling techniques used in this work and the calculation results are helpful for systematically understanding the properties of Ti1−xVxC and Ti1−xVxN in nanoscale.
Epidermal Electronic Systems for Measuring the Thermal Properties of Human Skin at Depths of up to Several Millimeters
Authors: Madhvapathy Surabhi R. , Ma Yinji , Patel Manish , Krishnan Siddharth , Wei Chen , Li Yajing , Xu Shuai , Feng Xue , Huang Yonggang , Rogers John A.
Published: June 2018

Monitoring the composition, blood flow properties, and hydration status of human skin can be important in diagnosing disease and tracking overall health. Current methods are largely limited to clinical environments, and they primarily measure properties of superficial layers of the skin, such as the stratum corneum (10–40 µm). This work introduces soft, skin‐like thermal depth sensors (e‐TDS) in designs that seamlessly couple with human skin and measure its thermal properties with depth sensitivity that can extend up to 6 mm beneath the surface. Guidelines for tailoring devices to enable measurements through different effective depths follow from a systematic set of experiments, supported by theoretical modeling. On‐body testing validates the physiological relevance of measurements using the e‐TDS platform, with potential to aid the diagnosis of deep cutaneous and systemic diseases. Specific demonstrations include measurements that capture responses ranging from superficial changes in skin properties that result from application of a moisturizer, to changes in microvascular flow at intermediate depths induced by heating/cooling, to detection of inflammation in the deep dermis and subcutaneous fat in an incidence of a local bacterial infection, cellulitis.
Impact of Graphene on the Efficacy of Neuron Culture Substrates
Authors: Fischer Rachel A. , Zhang Yuchen , Risner Michael L. , Li Deyu , Xu Yaqiong , Sappington Rebecca M.
Published: June 2018

How graphene influences the behavior of living cells or tissues remains a critical issue for its application in biomedical studies, despite the general acceptance that graphene is biocompatible. While direct contact between cells and graphene is not a requirement for all biomedical applications, it is often mandatory for biosensing. Therefore, it is important to clarify whether graphene impedes the ability of cells to interact with biological elements in their environment. Here, a systematic study is reported to determine whether applying graphene on top of matrix substrates masks interactions between these substrates and retinal ganglion cells (RGCs). Six different platforms are tested for primary RGC cultures with three platforms comprised of matrix substrates compatible with these neurons, and another three having a layer of graphene placed on top of the matrix substrates. The results demonstrate that graphene does not impede interactions between RGCs and underlying substrate matrix, such that their positive or negative effects on neuron viability and vitality are retained. However, direct contact between RGCs and graphene reduces the number, but increases basal activity, of functional cation channels. The data indicate that, when proper baselines are established, graphene is a promising biosensing material for in vitro applications in neuroscience.
Flexible Transient Optical Waveguides and Surface‐Wave Biosensors Constructed from Monocrystalline Silicon
Authors: Bai Wubin , Yang Hongjun , Ma Yinji , Chen Hao , Shin Jiho , Liu Yonghao , Yang Quansan , Kandela Irawati , Liu Zhonghe , Kang Seung‐Kyun , Wei Chen , Haney Chad R. , Brikha Anlil , Ge Xiaochen , Feng Xue , Braun Paul V. , Huang Yonggang , Zhou Weidong , Rogers John A.
Published: June 2018

Optical technologies offer important capabilities in both biological research and clinical care. Recent interest is in implantable devices that provide intimate optical coupling to biological tissues for a finite time period and then undergo full bioresorption into benign products, thereby serving as temporary implants for diagnosis and/or therapy. The results presented here establish a silicon‐based, bioresorbable photonic platform that relies on thin filaments of monocrystalline silicon encapsulated by polymers as flexible, transient optical waveguides for accurate light delivery and sensing at targeted sites in biological systems. Comprehensive studies of the mechanical and optical properties associated with bending and unfurling the waveguides from wafer‐scale sources of materials establish general guidelines in fabrication and design. Monitoring biochemical species such as glucose and tracking physiological parameters such as oxygen saturation using near‐infrared spectroscopic methods demonstrate modes of utility in biomedicine. These concepts provide versatile capabilities in biomedical diagnosis, therapy, deep‐tissue imaging, and surgery, and suggest a broad range of opportunities for silicon photonics in bioresorbable technologies.
Achieving Ultralow Wear with Stable Nanocrystalline Metals
Authors: Curry John F. , Babuska Tomas F. , Furnish Timothy A. , Lu Ping , Adams David P. , Kustas Andrew B. , Nation Brendan L. , Dugger Michael T. , Chandross Michael , Clark Blythe G. , Boyce Brad L. , Schuh Christopher A. , Argibay Nicolas
Published: June 2018

Recent work suggests that thermally stable nanocrystallinity in metals is achievable in several binary alloys by modifying grain boundary energies via solute segregation. The remarkable thermal stability of these alloys has been demonstrated in recent reports, with many alloys exhibiting negligible grain growth during prolonged exposure to near‐melting temperatures. Pt–Au, a proposed stable alloy consisting of two noble metals, is shown to exhibit extraordinary resistance to wear. Ultralow wear rates, less than a monolayer of material removed per sliding pass, are measured for Pt–Au thin films at a maximum Hertz contact stress of up to 1.1 GPa. This is the first instance of an all‐metallic material exhibiting a specific wear rate on the order of 10−9 mm3 N−1 m−1, comparable to diamond‐like carbon (DLC) and sapphire. Remarkably, the wear rate of sapphire and silicon nitride probes used in wear experiments are either higher or comparable to that of the Pt–Au alloy, despite the substantially higher hardness of the ceramic probe materials. High‐resolution microscopy shows negligible surface microstructural evolution in the wear tracks after 100k sliding passes. Mitigation of fatigue‐driven delamination enables a transition to wear by atomic attrition, a regime previously limited to highly wear‐resistant materials such as DLC.
Multilayer Lead‐Free Ceramic Capacitors with Ultrahigh Energy Density and Efficiency
Authors: Li Jinglei , Li Fei , Xu Zhuo , Zhang Shujun
Published: June 2018

The utilization of antiferroelectric (AFE) materials is thought to be an effective approach to enhance the energy density of dielectric capacitors. However, the high energy dissipation and inferior reliability that are associated with the antiferroelectric–ferroelectric phase transition are the main issues that restrict the applications of antiferroelectric ceramics. Here, simultaneously achieving high energy density and efficiency in a dielectric ceramic is proposed by combining antiferroelectric and relaxor features. Based on this concept, a lead‐free dielectric (Na0.5Bi0.5)TiO3‐x(Sr0.7Bi0.2)TiO3 (NBT‐xSBT) system is investigated and the corresponding multilayer ceramic capacitors (MLCCs) are fabricated. A record‐high energy density of 9.5 J cm−3, together with a high energy efficiency of 92%, is achieved in NBT‐0.45SBT multilayer ceramic capacitors, which consist of ten dielectric layers with the single‐layer thickness of 20 µm and the internal electrode area of 6.25 mm2. Furthermore, the newly developed capacitor exhibits a wide temperature usage range of ‐60 to 120 °C, with an energy‐density variation of less than 10%, and satisfactory cycling reliability, with degradation of less than 8% over 106 cycles. These characteristics demonstrate that the NBT‐0.45SBT multilayer ceramic is a promising candidate for high‐power energy storage applications.
Photocatalytic Growth of Hierarchical Au Needle Clusters on Highly Active TiO2 Thin Film
Authors: Veziroglu Salih , Ghori Muhammad Zubair , Kamp Marius , Kienle Lorenz , Rubahn Horst‐Günter , Strunskus Thomas , Fiutowski Jacek , Adam Jost , Faupel Franz , Aktas Oral Cenk
Published: June 2018

Hierarchical gold (Au) structures with sharp edges garner a strong interest for nanoelectronics, nanoenergy harvesting devices, and nano‐biomedical applications due the exceptional strong electric field (hot spot) enhancement at their tips. Herein, a facile method to synthesize hierarchical Au needle clusters (HAuNCs) on highly active titanium oxide (TiO2) thin film is reported. Different from surfactant‐directed photochemical‐assisted synthesis methods, a photocatalytic deposition approach is demonstrated, which allows positioning and patterning of HAuNCs on TiO2 target without using any surfactant or stabilizer. This green synthesis approach enables to control the size and the geometry of deposited HAuNCs by simply altering the photocatalytic activity of TiO2 target, UV light intensity, and irradiation time.
Ultrafast Nonlinear Optical Response in Plasmonic 2D Molybdenum Oxide Nanosheets for Mode‐Locked Pulse Generation
Authors: Wang Weiqi , Yue Wenjie , Liu Zhengzheng , Shi Tongchao , Du Juan , Leng Yuxin , Wei Rongfei , Ye Yuting , Liu Chang , Liu Xiaofeng , Qiu Jianrong
Published: June 2018

2D plasmons are of particular interest in the exploration of light–matter interactions in 2D materials. In 2D plasmonic materials, response time (in sub‐picosecond scale) of free carriers is order of magnitude faster than excitonic recombination in semiconductors, making them highly attractive for realizing faster optical switching and modulation in nanoscale devices. However, the small carrier density in gapless 2D plasmonic materials like graphene has strongly limited the strength of light–matter interaction and the operative spectral range. Here, it is shown that in optically activated plasmonic molybdenum oxide (MoO3) sheets of atomic thickness, the nonlinear optical (NLO) absorption, characterized by a saturable behavior in the near‐infrared region, is notably enhanced by the plasmon resonance, giving a modulation depth of 34.96%. Ultrafast pump‐probe spectroscopy reveals that the transient photobleaching in plasmonic MoO3 nanosheets associated with the relaxation of hot electrons recovers in a timescale less than 200 femtoseconds (fs). This ultrafast NLO response allows the development of an optical switch based on saturable absorption that enables the generation of mode‐locked laser pulses from a fiber laser operating at 1.0 µm region. The results may have strong implications for the application of 2D plasmonics based on 2D MoO3 in nanophotonics.
An Extended Grain‐Based Model for Characterizing Crystalline Materials: An Example of Marble
Authors: Wong Louis Ngai Yuen , Zhang Yahui
Published: June 2018

An extended grain‐based model (EGBM) is proposed with the purpose of explicitly incorporating morphological and metric characteristics of the crystalline structure for realistic simulation of crystalline materials. The objectives of this paper are twofold: (a) to improve the Voronoi grain‐based model (VGBM), and (b) to discuss several key challenges associated with model calibration. The EGBM is realized using the software Particle Flow Code (PFC) based on the principle of VGBM. To determine a representative EGBM, a simple calibration procedure taking the microcracking process into account is suggested. Using a crystalline rock as an example, three EGBMs with different rock structures as well as a conventional bonded‐particle model (BPM) have been examined to study the effect of geometric heterogeneity on physico‐mechanical behavior. The geometric heterogeneity of the three EGBMs is quantified by the geometric deviation index, which measures the standard deviation of fractal dimensions of the constitutive mineral grains. Simulation results suggest that: (1) BPM has very different microcracking mechanism from GBM owing to their different model formulations; (2) increasing irregularity of grain shape promotes the opening and sliding of grains along their boundaries; and (3) fracture complexity increases with increasing geometric heterogeneity.
Enhanced Photocatalytic Properties by Forming Tetragonal ZnX/PbO (X = S, Se) Hetero‐Bilayers: A Computational Prediction
Authors: Zhou Jia , Zhen Xiaofeng
Published: June 2018

The formation of van der Waals hetero‐layered structure is a promising strategy to improve the performance of 2D materials in energy‐related applications that is superior to the individual components. In the current theoretical work, first‐principles calculations are employed to investigate novel tetragonal (t‐) ZnX/PbO (X = S, Se) hetero‐bilayers (BLs). The state‐of‐the‐art computations based on quasiparticle GW and Bethe–Salpeter equation have been used to calculate the electronic and optical properties of t‐ZnX/PbO BLs. It is found that the t‐ZnX/PbO BLs have a strong optical absorption in the solar spectrum, making them potentially good candidates for solar energy harvesting. In addition, first‐principles calculations also show there is a clear charge transfer from ZnX layer to PbO layer.
Evolution of Interfacial Structure and Stress Induced by Interfacial Lattice Mismatch in Layered Metallic Nanocomposites
Authors: Hao Huali , Lau Denvid
Published: June 2018

The interfacial structure directly affects the intrinsic residual stress caused by the interfacial lattice mismatch in layered metallic composites. This stress plays a dominant role in the mechanical, optical, magnetic, and thermal properties of nanocomposites. Here, the interfacial structure evolution and atomistic origin of intrinsic residual stress are figured out through the in situ characterization of atom arrangement and rearrangement in layered metallic nanocomposites with different interfacial misfit by using an atomistic approach. It is found that with the increment of the interfacial misfit, the interface roughens while the intrinsic residual stress increases and then reduces. The film structure dominates the evolution of interfacial structure and intrinsic residual stress when the interfacial misfit is low, whereas the effect of substrate structure on the interface and the stress is as important as the film structure with the increase of the interfacial misfit. The work demonstrates how the film structures affect the interfacial structure and intrinsic stress in layered metallic nanocomposites. Both the film and substrate structures should be taken into consideration to design layered composites with excellent properties.
Phototunable Biomemory Based on Light‐Mediated Charge Trap
Authors: Lv Ziyu , Wang Yan , Chen Zhonghui , Sun Long , Wang Junjie , Chen Meng , Xu Zhenting , Liao Qiufan , Zhou Li , Chen Xiaoli , Li Jieni , Zhou Kui , Zhou Ye , Zeng Yu‐Jia , Han Su‐Ting , Roy Vellaisamy A. L.
Published: June 2018

Phototunable biomaterial‐based resistive memory devices and understanding of their underlying switching mechanisms may pave a way toward new paradigm of smart and green electronics. Here, resistive switching behavior of photonic biomemory based on a novel structure of metal anode/carbon dots (CDs)‐silk protein/indium tin oxide is systematically investigated, with Al, Au, and Ag anodes as case studies. The charge trapping/detrapping and metal filaments formation/rupture are observed by in situ Kelvin probe force microscopy investigations and scanning electron microscopy and energy‐dispersive spectroscopy microanalysis, which demonstrates that the resistive switching behavior of Al, Au anode‐based device are related to the space‐charge‐limited‐conduction, while electrochemical metallization is the main mechanism for resistive transitions of Ag anode‐based devices. Incorporation of CDs with light‐adjustable charge trapping capacity is found to be responsible for phototunable resistive switching properties of CDs‐based resistive random access memory by performing the ultraviolet light illumination studies on as‐fabricated devices. The synergistic effect of photovoltaics and photogating can effectively enhance the internal electrical field to reduce the switching voltage. This demonstration provides a practical route for next‐generation biocompatible electronics.
Insights into identifying habitat hot spots and migratory corridors of green turtles in the South China region
Authors: Ng Connie Ka Yan , Gu He Xiang , Li Tsung Hsien , Ye Ming Bin , Xia Zhong Rong , Zhang Fei Yan , Duan Jin Xia , Hsu Chung Kang , Balazs George H. , Murphy Margaret B.
Published: June 2018

Sea turtles are globally endangered, and face daily anthropogenic threats, such as direct take, by‐catch, and habitat degradation. Current research efforts on sea turtles in the South China region mainly focus on captivity and husbandry, haematology and blood chemistry, and nesting ecology. Published information on the marine habitat use of wild populations is limited.

This situation therefore creates a pressing need for scientific research on free‐ranging sea turtles as a foundation for habitat management and species protection in South China. In this study, habitat use and oceanic movement of nesting, and by‐catch or stranded green turtles, were determined by satellite tracking combined with home‐range analysis.

Coupled with previous findings, the foraging grounds of several sea turtle species (green turtle Chelonia mydas, hawksbill turtle Eretmochelys imbricata and loggerhead Caretta caretta) were mainly distributed along the coasts of Hainan Island Province and Guangdong Province, mainland China, as well as Taiwan and the Philippines, and the outlying islands in the South China Sea and East China Sea.

Habitat hot spots and migratory corridors of green turtles, in particular nesting turtles in South China, were identified. Coastal waters near Wanning City of Hainan Island, the eastern Leizhou Peninsula, Iriomote‐jima and Ishigaki‐shima of the Ryukyu Islands of Japan, and Dao Bach Long Vi of Vietnam serve as foraging grounds for nesting green turtles from different origins in South China. Moreover, the Paracel (Xisha) and the Pratas (Dongsha) Islands in the South China Sea, Huidong Gangkou, and its vicinity in mainland China, and Liouciou Island and Penghu Island of Taiwan contain both nesting sites and foraging grounds for green turtles.

The sites that are associated with migratory corridors, in particular Hainan Island, eastern Leizhou Peninsula, and Liouciou Island, which currently lack conservation plans for sea turtles, should be given higher priority for habitat and species protection.
Synthesis and biological evaluation of some new tricyclic pyrrolo[3,2‐e]tetrazolo[1,5‐c]pyrimidine derivatives as potential antitubercular agents
Authors: Patil Yogesh , Shingare Ramesh , Choudhari Amit , Borkute Rachana , Sarkar Dhiman , Madje Balaji R.
Published: June 2018

A series of new tricyclic pyrrolo[3,2‐e]tetrazolo[1,5‐c]pyrimidines 8a–l were synthesized and characterized by IR, NMR (1H and 13C), and mass spectral analysis. The newly synthesized compounds 8a–l were inspected for their in vitro antitubercular activity against Mycobacterium tuberculosis (MTB) H37Ra using an established XTT reduction menadione assay (XRMA). The title compounds exhibited minimum inhibitory concentrations (MIC90) ranging from 0.09 to >30 μg/mL. Five compounds (8c, 8i–l) were further confirmed for their dose‐dependent effect against MTB. These compounds were evaluated in the THP‐1 infection model, where 8i (MIC90 = 0.35 μg/mL), 8j (MIC90 = 1.17 μg/mL), 8k (MIC90 = 2.38 μg/mL), and 8l (MIC90 = 1.17 μg/mL) demonstrated significant antitubercular activity. All the ex vivo active compounds showed insignificant cytotoxicity against the human cancer cell lines, HeLa, MCF‐7, and THP‐1. Inactivity of all these compounds against Gram positive and Gram negative bacteria indicates their specificity. Molecular docking studies in the active site of the sterol 14alpha‐demethylase (CYP51) enzyme revealed a similar binding mode to the native ligand in the crystal structure, thereby helping to understand the ligand–protein interactions and to establish a structural basis for inhibition of MTB. The results suggest novel pharmacophores as selective and specific inhibitors against MTB that can be explored further to synthesize lead compounds against tuberculosis. In summary, the results clearly indicate the identification of some novel, selective, and specific inhibitors against MTB that can be explored further for potential antitubercular drugs.
The effect of small perturbations in the Coriolis and centrifugal forces on the existence of libration points in the restricted four‐body problem with variable mass
Authors: Aggarwal R. , Mittal A. , Suraj M. S. , Bisht V.
Published: June 2018

This paper shows the effect of small perturbations in the Coriolis and centrifugal forces in the restricted four‐body problem (R4BP) with variable mass. The existence, location, and stability of the libration points are investigated numerically and graphically under these perturbations. In the present problem, a fourth body with infinitesimal mass is moving under the Newtonian gravitational attraction of three primaries which are moving in a circular orbit around their common center of mass fixed at the origin of the coordinate system. Moreover, according to the solution of Lagrange, the primaries are fixed at the vertices of an equilateral triangle. The fourth body does not affect the motion of three primaries. Furthermore, the fourth body's mass varies according to Jeans' law. The equations of motion of the test particle, i.e., fourth body moving under the gravitational influence of the primaries, are derived. Throughout the paper, we consider the case where the primary body placed along the x‐axis is dominant while the other two small primaries are equal. Further, it is shown that there exist either 8 or 10 libration points out of which 2 or 4 are collinear with the dominating primary and the rest are non‐collinear for fixed values of the parameters. The linear stability of all the libration points under consideration is investigated, and these libration points are found to be unstable. The allowed regions of motion are determined by using the zero‐velocity surface, and the positions of the libration points on the orbital plane are presented. Moreover, by using the Newton–Raphson iterative scheme, we unveiled the effects of the Coriolis and centrifugal forces on the topology of the basins of convergence associated with the libration points.
A One‐Pot “Triple‐C” Multicyclization Methodology for the Synthesis of Highly Constrained Isomerically Pure Tetracyclic Peptides
Authors: Richelle Gaston J. J. , Schmidt Marcel , Ippel Hans , Hackeng Tilman M. , van Maarseveen Jan H. , Nuijens Timo , Timmerman Peter
Published: June 2018

A broadly applicable one‐pot methodology for the facile transformation of linear peptides into tetracyclic peptides through a chemoenzymatic peptide synthesis/chemical ligation of peptides onto scaffolds/copper(I)‐catalyzed reaction (CEPS/CLIPS/CuAAC; “triple‐C”) locking methodology is reported. Linear peptides with varying lengths (≥14 amino acids), comprising two cysteines and two azidohomoalanines (Aha), were efficiently cyclized head‐to‐tail by using the peptiligase variant omniligase‐1 (CEPS). Subsequent ligation–cyclization with tetravalent (T41/2) scaffolds containing two bromomethyl groups (CLIPS) and two alkyne functionalities (CuAAC) yielded isomerically pure tetracyclic peptides. Sixteen different functional tetracycles, derived from bicyclic inhibitors against urokinase plasminogen activator (uPA) and coagulation factor XIIa (FXIIa), were successfully synthesized and their bioactivities evaluated. Two of these (FF‐T41/2) exhibited increased inhibitory activity against FXIIa, compared with a bicyclic control peptide. The corresponding hetero‐bifunctional variants (UF/FU‐T41/2), with a single copy of each inhibitory sequence, exhibited micromolar activities against both uPA and FXIIa; thus illustrating the potential of the “bifunctional tetracyclic peptide” inhibitor concept.
Successful treatment of dens invaginatus type 3 with infected invagination, vital pulp, and cystic lession: A case report
Authors: Dembinskaite Ausra , Veberiene Rita , Machiulskiene Vita
Published: June 2018

Key Clinical Message

All efforts should be aimed to safe permanent tooth for adolescents. Presented rare case confirms a possibility to save a tooth with Oehlers Type 3 anomaly with peri‐invaginated periodontitis and to preserve vitality of the tooth pulp, even when surgical cyst removal is performed.
Penile lesion in a dialysis patient: Time to get an X‐ray
Authors: Koratala Abhilash , Chamarthi Gajapathiraju
Published: June 2018

Key Clinical Message

Calciphylaxis or calcific uremic arteriolopathy is a rare and serious disorder typically seen in patients with end‐stage renal disease that manifests as skin ischemia and necrosis and histologically characterized by calcification of dermal arterioles. Penis is a rare site of involvement and biopsy is not typically recommended, making the diagnosis clinico‐radiologic.
Oxoberyllates SrBeO2 and Sr12Be17O29 as Novel Host Materials for Eu2+ Luminescence
Authors: Strobel Philipp , Niklaus Robin , Schmidt Peter J. , Schnick Wolfgang
Published: June 2018

Beryllate structures are marginally investigated, but show intriguing structural relations to oxo‐ and nitridosilicates. A typical feature is the coordination of Be in both trigonal planar and tetrahedral coordination by O. A broad range of structures is accessible by variable combinations of both building units. Three novel ternary Sr‐oxoberyllates are characterized by single‐crystal X‐ray diffraction analysis, density functional theory calculations and investigations on luminescence properties: α‐SrBeO2, β‐SrBeO2 and Sr12Be17O29 are obtained with oxoberyllate substructures, made up of either BeO3 triangles or BeO4 tetrahedra. The compounds can be described as chain‐ and layer‐type beryllates. When excited with blue light of (In,Ga)N LED chips, β‐SrBeO2 and Sr12Be17O29 show visible emission in the yellow and orange spectral range, respectively, upon doping with Eu2+. Exceptional narrow‐band yellow emission (λem=564 nm, fwhm=55 nm) makes β‐SrBeO2:Eu2+ a promising phosphor for application in phosphor‐converted (pc‐)LEDs.