bluuebunny/crossref_metadata_2025 huggingface dataset:
Povos da floresta: a luta pela autodeterminação e contra o capital
Authors: Da Cunha Manoel Estébio Cavalcante , Lobão Moisés Silveira
Published: September 2021

O estudo visa analisar como as terras do sudoeste da Amazônia foram povoadas por diversas etnias, primeiro indígenas, depois grupos do nordeste brasileiro e finalmente do sul do país, culminando na luta dos "Povos da Floresta" por seus territórios. Este estudo realizado por meio de uma pesquisa bibliográfica, abrangeu os seguintes momentos históricos: as etnias indígenas existentes no território da tríplice fronteira Madre de Dios (Peru), Acre (Brasil) e Pando (Bolívia) - MAP; as ocupações nesta região após a colonização hispano-portuguesa; o 1º e 2º Ciclo da Borracha. A resistência dos seringueiros e conquista da Resex e a conciliação dos movimentos sociais com a oligarquia, através do capitalismo verde.
Materialismo histórico-dialético e interdisciplinaridade: por uma leitura ontometodológica na pesquisa em educação ambiental
Authors: Costa César Augusto , Loureiro Carlos Frederico
Published: September 2021

O debate sobre a interdisciplinaridade com base no materialismo histórico-dialético para a pesquisa em Educação Ambiental (EA) torna-se fundamental para a compreensão da realidade, cujo processo denominamos de leitura ontometodológica. Refletir sobre a interdisciplinaridade, supõe também considerar a configuração histórica da pesquisa em EA, a qual é composta, de um lado, por múltiplos segmentos, grupos e classes sociais que compõem a sociedade contemporânea e, de outro, por pesquisadores no campo que compartilham perspectivas teórico-metodológicas comuns. A questão central, é que tais pesquisadores também se diferenciam em suas concepções sobre a questão ambiental e nas posições políticas, ideológicas, pedagógicas e epistêmicas que defendem ao realizarem o enfrentamento dos problemas ambientais sob a égide do projeto societário capitalista. Nesse cenário de disputa epistêmica no campo, organizamos o artigo em três momentos articulados: em seu momento inicial, abordaremos as relações entre totalidade, materialismo histórico-dialético e pesquisa em EA; no segundo, elencaremos a crítica ontometodológica a partir da interdisciplinaridade na pesquisa em EA. Por fim, nas reflexões finais, sustentaremos que a interdisciplinaridade não deve ser apregoada de maneira homogênea e apolítica em seu fazer educativo, pois tal compreensão silencia ou nega que há diferenças epistêmicas e políticas no campo.
O Ensino Superior: as Antígonas de nosso tempo pandêmico e o agravo das desigualdades sociais
Authors: Menezes Magali Mendes de , Costa Pedro de Almeida
Published: September 2021

A pandemia que vivemos escancarou e, ao mesmo tempo, provocou um agravo nas desigualdades sociais históricas do Brasil. Essa condição é consequência de processos de colonização que são vividos até hoje, pois não conseguimos enfrentar o racismo, a violência de gênero, a exploração do trabalho e outras mazelas sociais. Todas estas questões, em um tempo de profunda fragilidade sanitária, nos mostram que os que mais sofrem continuam sendo os mais pobres. A COVID-19 nos apresenta a face mais violenta desta desigualdade. O campo da Educação também é afetado por este cenário, e neste texto discutimos o caso da educação superior em um uma universidade pública, para problematizar a permanência de processos de exclusão. Com a suspensão das aulas, busca-se compensar o ensino presencial através de propostas de atividades remotas (ERE). A implementação da proposta poderá aprofundar as desigualdades, dadas as condições precárias com que está se dando essa discussão, na qual aparecem invisibilizadas as dificuldades daquele público que tem sido trazido para a universidade nos últimos anos através de políticas afirmativas.
Enhancing ecological integrity while preserving ecosystem services: Constructing soft‐sediment islands in a shallow lake
Authors: van Leeuwen Casper H.A. , Temmink Ralph J.M. , Jin Hui , Kahlert Yvonne , Robroek Bjorn J.M. , Berg Matty P. , Lamers Leon P.M. , van den Akker Marloes , Posthoorn Roel , Boosten Annemiek , Olff Han , Bakker Elisabeth S.
Published: September 2021

Ecosystems are increasingly managed to provide multiple benefits to humans, which often degrades their ecological integrity. This strongly applies to aquatic ecosystems, in which engineering can enhance flood protection, drinking water supply, fisheries and recreation. Although these activities typically increase ecosystem functionality to humans, they often impair key aspects of biodiversity and natural functioning.

Classical restoration of such degrading freshwater ecosystems can lead to societal opposition, if returning to a former ecosystem state affects previously acquired ecosystem services. Innovative nature‐based solutions are therefore needed that enhance natural values in ecosystems, without affecting existing services.

We present a large‐scale project aiming to increase the ecological integrity of a human‐modified freshwater lake while maintaining its services to humans. The freshwater lake Markermeer in the Netherlands was formed by closing off an estuary for flood protection. The ecological integrity of this lake diminished over time, likely because a declining primary productivity impaired biodiversity at higher trophic levels. This decline is associated with a lack of gradual land–water transitions, strong resuspension of fine sediments, low nutrient availability and lack of dynamics typically to be expected in a natural temperate freshwater lake. Restoring the lake to its former marine state would conflict with current ecosystem services.

A nature‐based solution was initiated in 2016, consisting of constructing a five‐island archipelago from the lake's own soft‐sediments called the ‘Marker Wadden’. The project aims to increase the lake's primary production by creating gradual land–water transitions, more heterogeneity in water depths and decreasing turbidity by creating shelter and deep sinks reducing fine‐sediment resuspension by the wind – thus introducing currently missing elements that are typical for natural lakes. We present the underlying ecological framework and first scientific results of this innovative ongoing project.

Within 4 years, the Marker Wadden project shows how forward‐looking sustainable development of lake ecosystems using a rewilding approach can enhance natural processes and attract birds and fish, without conflicting with existing ecosystem services. This inspires new directions for halting and reversing the degradation of other vital ecosystems worldwide.
Universal Grammar
Authors: White Lydia
Published: September 2021

This entry outlines arguments that universal grammar (UG) constrains the acquisition of the mother tongue, along with arguments that UG continues to constrain non‐native language acquisition, which helps explain the acquisition of linguistic competence. Pedagogical implications are considered, including the advantages offered by sophisticated linguistic descriptions, as well as the issue of how learnability considerations can highlight problem areas for second language learners, with potential insights for language teaching.
Bilingual Programs
Authors: Ennis Michael J. , Taylor Shelley K.
Published: September 2021

In the English‐speaking world, bilingual programs have a complex and dynamic history, which is as old as the English language itself. Yet a distinction is often made between additive bilingual education, which fosters individual and societal bilingualism, and subtractive bilingual education, which maintains the status quo of monolingualism. Bilingual programs can be further divided into strong forms, which entail substantial second or foreign language exposure and instruction, and weak forms, which entail significantly less exposure and instruction. Research suggests that strong, additive forms are most effective at fostering bilingualism and integrating minority communities into society, and are often more effective at teaching other subjects. There are, however, a myriad of variables that can impact the success of any program.
Teaching/Developing Vocabulary Using Think‐Aloud and Read‐Aloud Strategies
Authors: Lapp Diane , Wolsey Thomas Devere
Published: September 2021

Thinking aloud and reading aloud are two instructional practices intended to provide learners with models of proficient language use and strategic thinking. As in any instructional practice, teachers must be clear about both purpose and anticipated outcomes when implementing a think‐aloud or a read‐aloud strategy. Teacher clarity means that the teacher knows what to teach, how to teach it, and what learning successes are expected. Hattie's meta‐analysis of thousands of studies aggregates data from many of them and identifies the effect size of teacher clarity as 0.75. This is quite significant, since 0.4 is suggested by Hattie as the “hinge point”: all percentages above that work well to promote learning and instruction. While his initial listings are often updated through inclusion of new studies, the powerful effect size of teacher clarity remains consistent.

Early readers are often introduced to many of the conventions of reading – such as book handling, print conventions, and language and text structures – during a read aloud or a think aloud. While engaging students and fostering learning and academic language development, both strategies are powerful motivational supports for students throughout the grades, especially English learners because they facilitate their hearing academic language produced by a capable reader and speaker. This entry outlines the traditions of thinking aloud and reading aloud and then focuses on the use of these two instructional practices relative to vocabulary development.
3‐Dimensional Printing of Hydrogel‐Based Nanocomposites: A Comprehensive Review on the Technology Description, Properties, and Applications
Authors: Soleymani Eil Bakhtiari Sanaz , Bakhsheshi-Rad Hamid Reza , Karbasi Saeed , Razzaghi Mahmood , Tavakoli Mohamadreza , Ismail Ahmad Fauzi , Sharif Safian , RamaKrishna Seeram , Chen Xiongbiao , Berto Filippo
Published: September 2021

Increasing demand for customized implants and tissue scaffolds requires advanced biomaterials and fabricating processes for fabricating three‐dimensional (3D) structures that resemble the complexity of the extracellular matrix (ECM). Lately, biofabrication approaches such as cell‐laden (soft) hydrogel 3D printing (3DP) have been of increasing interest in the development of 3D functional environments similar to natural tissues and organs. Hydrogels that resemble biological ECMs can provide mechanical support and signaling cues to cells to control their behavior. Although the capability of hydrogels to produce artificial ECMs can regulate cellular behavior, one of the major drawbacks of working with hydrogels is their inferior mechanical properties. Therefore, keeping and enhancing the mechanical integrity of fabricated scaffolds has become an essential matter for 3D hydrogel structures. Herein, 3D‐printed hydrogel‐based nanocomposites (NCs) are evaluated systematically in terms of introducing novel techniques for 3DP of hydrogel‐based materials, properties, and biomedical applications.
Ultrasonic Spray Coating of Silver Nanowire‐Based Electrodes for Organic Light‐Emitting Diodes
Authors: Verboven Inge , Silvano Joao , Elen Ken , Pellaers Hilde , Ruttens Bart , D'Haen Jan , Van Bael Marlies K. , Hardy An , Deferme Wim
Published: September 2021

The expanding field of flexible organic electronics has led to a high demand for flexible, stable, and transparent electrodes that retain their conductivity at high‐strain deformation. Among many transparent conductive electrodes (TCEs) of which indium tin oxide (ITO) is the most renowned, silver nanowires (AgNWs) prove to be an excellent highly conductive and transparent alternative. These 1D silver nanostructures form a flexible mesh of nanometer‐thin wires that can be applied using solution‐processing and printing techniques. Ultrasonic spray coating is a high‐end low‐cost, environmentally friendly, and roll‐to‐roll compatible printing technique. AgNWs with three different diameters (50, 70, and 115 nm) are ultrasonically spray coated on glass and demonstrate sheet resistances lower than 10 Ω sq−1 combined with transparencies up to 88%. Consequently, the conductive polymer poly(3,4‐ethylenedioxythio‐phene):poly(styrene sulfonate) (PEDOT:PSS) is ultrasonically spray coated to fill up the cavities between the AgNW mesh and to planarize the surface. The ultrasonically spray coated AgNWs/PEDOT:PSS electrodes are employed as TCEs for organic light‐emitting diodes (OLEDs) showing very promising results with a luminous flux of 1.75 lm and a luminous efficacy of about 11 lm W−1 at 3 V driving voltage. Herein, ultrasonic spray coating is demonstrated as an excellent printing technique to apply AgNWs and PEDOT:PSS.
Low‐Dimensional Black Phosphorus in Sensor Applications: Advances and Challenges
Authors: An Dong , Zhang Xiao , Bi Zhaoshun , Shan Wei , Zhang Han , Xia Shuwei , Qiu Meng
Published: September 2021

Low‐dimensional black phosphorus (LDBP) materials have emerged, with considerable application potential in sensing due to their unique folded structures and remarkable physicochemical properties. These include anisotropies, layer‐dependent and tunable band gaps, high carrier mobilities, high current switching ratios, and excellent electron donor capacities. As a type of supporting material that is favorable to signal transmission or reception, LDBP is widely researched in piezoelectric, flexible, chemical, and biomolecular sensors. This review summarizes the synthetic methods, properties, and modification strategies of LDBP, and then mainly focuses on the research progress in LDBP‐based sensor applications, including physical and chemical sensors and biosensors. The major issues in LDBP‐based sensor applications are also discussed. Finally, the prospects and challenges in the field of LDBP‐based sensors are analyzed.
Spatially Confined CVD Growth of High‐Density Semiconducting Single‐Walled Carbon Nanotube Horizontal Arrays
Authors: Qian Liu , Shao Qian , Yu Yue , Liu Weiming , Wang Shanshan , Gao Enlai , Zhang Jin
Published: September 2021

High‐density horizontally aligned single‐walled carbon nanotube (SWNT) arrays with high‐purity semiconducting tubes are promising materials for energy‐efficient electronics. However, realizing high density and high semiconducting purity through the direct‐growth method is still a challenge. Here the problem is overcome through a spatially confined approach based on a floating solid catalyst chemical vapor deposition (FSCCVD) system. A confined space is designed to change the fluid dynamics in a chemical vapor deposition reactor, offering a trapping effect for both catalyst nanoparticles and carbon fragments. Therefore, densely and uniformly distributed catalyst nanoparticles are continuously deposited on substrates, greatly increasing the growth probability and efficiency of SWNTs. Besides, the solid catalyst TiC and the oxygen‐vacancy‐enriched catalyst TiO both facilitate the growth of semiconducting tubes. As a result, SWNT horizontal arrays with a high density of 65 tubes µm−1 and a semiconducting purity of >95% are realized, which hold the potential for future application in carbon nanotube electronics.
Radial Pores in Nitrogen/Oxygen Dual‐Doped Carbon Nanospheres Anode Boost High‐Power and Ultrastable Potassium‐Ion Batteries
Authors: Deng Hongli , Wang Lei , Li Shengyang , Zhang Meng , Wang Tao , Zhou Jian , Chen Maoxin , Chen Song , Cao Jinhui , Zhang Qiusheng , Zhu Jian , Lu Bingan
Published: September 2021

Constructing electrode materials with fast ions and electrons transport channels is an effective solution to achieve high‐power‐density and long‐cycle potassium‐ion batteries (PIBs). Herein, completely opening radial pores in N/O dual‐doped carbon nanospheres (RPCNSs) are constructed as anode for high‐power PIBs. The RPCNS with hierarchical structure (micro/meso/macropores and radial channels) and N/O dual‐doping permits speedy ions and electrons transportation within the carbon nanospheres anode, achieving a reversible capacity of 346 mAh g−1 at 50 mA g−1 after 360 cycles and long‐term cycling life over 2000 cycles without obvious capacity attenuation. The in situ Raman and kinetic analysis (in situ electrochemical impedance spectroscopy and galvanostatic intermittent titration) suggest that the exquisitely designed pore structure and heterodoping enable highly reversible electrochemical reaction and fast de/intercalation kinetics. Moreover, the full cells packaged with RPCNS anode can be fully charged in 10 s and exhibit the highest charge power density of 24 866 W kg−1 and longest cycling endurance of 5000 cycles in reported PIBs. The unique structural engineering provides a new way for high‐power density potassium‐ion storage devices.
Recent Progress on Metal‐Based Nanomaterials: Fabrications, Optical Properties, and Applications in Ultrafast Photonics
Authors: Fu Bo , Sun Jingxuan , Cheng Yuan , Ouyang Hao , Compagnini Giuseppe , Yin Peng , Wei Songrui , Li Shaojuan , Li Dabing , Scardaci Vittorio , Zhang Han
Published: September 2021

Nanomaterials have demonstrated excellent mechanical, thermal, optical, and electrical properties in various fields, including 1D carbon nanotubes, as well as 2D materials starting from graphene. Metal‐based nanomaterials, mainly divided into metal and metal oxide nanoparticles, also gradually come into the sight of ultrafast photonics applications due to the outstanding optical properties. The optical properties of metal nanoparticles can be enhanced by the interaction between conduction electrons with electric fields that is called surface plasmon resonance. As for metal oxide nanoparticles, optical properties are closely related to bandgap structures. When it comes to transition metal oxides, other phenomena also play important roles in optical absorption such as spin inversion and excitons of iron. Moreover, preparation methods of materials are also crucial for their properties and further applications. Therefore, in this review, commonly used physical and chemical fabrication methods for metal‐based nanomaterials are first introduced. Then the optical properties of typical metal and metal oxide nanoparticles are discussed specifically. In addition, the applications of metal‐based nanomaterials in ultrafast lasers based on mode‐locked and Q‐switched techniques are also summarized. Finally, a summary and outlook toward the synthesis, optical properties, and applications in ultrafast photonics of metal‐based nanomaterials are presented.
Integration of Morphology and Electronic Structure Modulation on Atomic Iron‐Nitrogen‐Carbon Catalysts for Highly Efficient Oxygen Reduction
Authors: Xin Cuncun , Shang Wenzhe , Hu Jinwen , Zhu Chao , Guo Jingya , Zhang Jiangwei , Dong Haopeng , Liu Wei , Shi Yantao
Published: September 2021

Atomic transition‐metal‐nitrogen‐carbon catalysts (M‐N‐Cs) hold great promise as Pt‐group‐metal‐free candidates for electrochemical reactions, yet their rational design and controllable synthesis remain fundamental challenges. Here, the molten‐salts mediated pyrolysis is demonstrated to be an effective and facile strategy for simultaneous morphology and electronic structure modulation of prototypical Fe‐N‐C materials, which functions as efficient oxygen reduction electrocatalysts. Taking advantage of the strong polarity and salt templating effects, the as‐obtained Fe‐N/C‐single atom catalyst (SAC) possesses hierarchical porous nanosheet morphology with an impressive specific surface area of 2237 m2 g−1 and unique FeN4Cl moieties as isolated active centers. The Fe‐N/C‐SAC delivers remarkable alkaline oxygen reduction reaction (ORR) activity with a half‐wave potential of 0.91 V and record kinetic current density up to 55 mA cm−2, outperforming the benchmark Pt/C. By virtue of dechlorination treatment, it is experimentally identified that the enhanced ORR activities are essentially governed by the axially bound Cl. Theoretical calculations rationalize this finding and demonstrate that the well‐defined fivefold‐coordinated configuration accelerates 4e− pathway kinetics through near‐optimal adsorption of the *OH intermediates and tunes the potential determining step from *OH reduction to *OOH formation. This study provides fundamental insights into the coordination‐engineered strategy in single‐atom catalysis.
Highly Nonlinear Optical Organic Crystals for Efficient Terahertz Wave Generation, Detection, and Applications
Authors: Kim Seung‐Jun , Kang Bong Joo , Puc Uros , Kim Won Tae , Jazbinsek Mojca , Rotermund Fabian , Kwon O‐Pil
Published: September 2021

Organic π‐conjugated crystals with second‐order optical nonlinearity are considerably attractive materials for diverse terahertz (THz) wave photonics. An overview of the research of organic nonlinear optical (NLO) crystals for THz wave generation, detection, and applications is provided here. First, the status of organic NLO crystals compared to other alternative THz materials is described. Second, the basic theory and requirements for organic THz generators and detectors are explained. Third, with a primary focus on the organic NLO crystals that have been developed during the last decade, various molecular engineering approaches are discussed from the perspective of THz photonics. Finally, various types of high‐power broadband coherent THz sources and their applications in THz nonlinear optics are discussed.
Fine‐Tuning the Photovoltaic Performance of Organic Solar Cells by Collaborative Optimization of Structural Isomerism and Halogen Atom
Authors: Li Zhe , Zhang Na , Chen Honggang , Peng Hongjian , Zou Yingping
Published: September 2021

Fused‐ring acceptors based on an electron‐deficient core, such as Y6, have become a successful strategy in bulk heterojunction (BHJ) organic solar cells (OSCs) for high power conversion efficiencies (PCEs). Here, five fused‐ring electron acceptors (Y9, Y9‐2F, Y9‐2Cl, i‐Y9‐2F, i‐Y9‐2Cl) are synthesized using fused dithienothiophen[3,2‐b]pyrrolobenzotriazole and halogenated 1,1‐dicyanomethylene‐3‐indanone (IC) to investigate the effect of end‐group (EG) halogenation and structural isomerism on BHJ photovoltaic performance. Due to the strong electronegativity of halogens, all the acceptors with halogenated terminal units possess redshifted absorption spectra and deeper frontier energy levels compared with Y9. Different from asymmetric molecules i‐Y9‐2F and i‐Y9‐2Cl, Y9‐2F and Y9‐2Cl exhibit slightly lower bandgaps. Moreover, the devices based on fluorinated acceptors show more efficient charge collection, obtaining relatively high short‐circuit current density (J
sc) and fill factor (FF). The lowest unoccupied molecular orbital energy levels of halogenated acceptors are similar. As a result, OSCs based on poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithio‐phene))‐alt‐(5,5‐ (1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethyl‐hexyl) benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione))] (PBDB‐T):Y9‐2F obtain more balanced J
sc and open‐circuit voltage (V
oc), and thus an optimal PCE of 15.49% is demonstrated with a V
oc of 0.84 V, J
sc of 26.30 mA cm−2, and FF of 70.05%.
Structure of nanoparticle‐polyelectrolyte complexes: Effects of polyelectrolyte characteristics and charge ratio
Authors: Holkar Advait , Toledo Jesse , Srivastava Samanvaya
Published: September 2021

We present structural and turbidimetric characterizations of aqueous dispersions of oppositely charged nanoparticles and polyelectrolytes that undergo complexation and flocculation to form particle‐rich agglomerates over a wide range of polyelectrolyte and nanoparticle concentrations with varying polyelectrolyte sizes and persistence lengths. Compaction of nanoparticles in the polyelectrolyte–nanoparticle complexes, signified by decreasing internanoparticle spacing until they are brought in near‐contact, is observed upon increasing screening of interparticle repulsion arising from adsorption of polyelectrolytes on the nanoparticle surfaces. We identify the ratio of charge borne by the polyelectrolytes and the nanoparticles as a key parameter dictating the compaction of nanoparticles into complexes as well as densification of complexes into agglomerates. Moreover, the emergence of turbidity in solution is shown to correlate with the initiation of nanoparticle compaction by polyelectrolytes but failing to describe further structural evolution of the complexes, emphasizing the need for alternate characterization techniques.
Semianalytical method of two‐phase liquid transport in shale reservoirs and its application in fracture characterization
Authors: Zhang Fengyuan , Emami‐Meybodi Hamid
Published: September 2021

This study presents a new semi‐analytical method to simulate the two‐phase liquid transport in hydraulic fractures (HF) and matrix system, which can be applied to characterize HF attributes and dynamics using the flowback data from hydraulically fractured shale oil wells. The proposed approach includes a fracture model for HF properties calculation and a matrix model capable of considering multiple liquid transport mechanisms in shale nanopores. The proposed method is first validated with the numerical simulation then applied to a field example in Eagle Ford shale. The numerical validation confirms that our method can accurately characterize fracture attributes and closure dynamics by closely estimating the initial fracture permeability, pore‐volume, compressibility, and permeability modulus. Furthermore, the analysis results from numerical simulation and a field example both indicate a clear flow enhancement and deficit for oil and water transport, respectively, due to the slippage effect and variation of fluid properties inside nanopores.
Tuneable Time Delay in the Burst Release from Oxidation‐Sensitive Polymersomes Made by PISA
Authors: Sobotta Fabian H. , Kuchenbrod Maren T. , Gruschwitz Franka V. , Festag Grit , Bellstedt Peter , Hoeppener Stephanie , Brendel Johannes C.
Published: September 2021

Reactive polymersomes represent a versatile artificial cargo carrier system that can facilitate an immediate release in response to a specific stimulus. The herein presented oxidation‐sensitive polymersomes feature a time‐delayed release mechanism in an oxidative environment, which can be precisely adjusted by either tuning the membrane thickness or partial pre‐oxidation. These polymeric vesicles are conveniently prepared by PISA allowing the straightforward and effective in situ encapsulation of cargo molecules, as shown for dyes and enzymes. Kinetic studies revealed a critical degree of oxidation causing the destabilization of the membrane, while no release of the cargo is observed beforehand. The encapsulation of glucose oxidase directly transforms these polymersomes into glucose‐sensitive vesicles, as small molecules including sugars can passively penetrate their membrane. Considering the ease of preparation, these polymersomes represent a versatile platform for the confinement and burst release of cargo molecules after a precisely adjustable time span in the presence of specific triggers, such as H2O2 or glucose.
Two new Cu (II) complexes based on 5‐fluorouracil‐1‐yl acetic acid and N‐donor ligands: Investigation of their interaction with DNA and anticancer activity
Authors: Xi Yun‐Hong , Yan Xin , Bigdeli Fahime , Zhang Qianwen , Esrafili Leili , Hanifehpour Younes , Zhang Wei‐Bing , Hu Mao‐Lin , Morsali Ali
Published: September 2021

Two new Cu (II) complexes [Cu (bpy)2L1] BF4.CH3OH (Z3) and [Cu (phen)2L1] BF4·H2O (Z9), L1 = 5‐Fluorouracil‐1‐yl Acetic Acid, were synthesized based on 5‐Fluorouracil‐1‐yl Acetic Acid and 2,2′‐Bipyridine or 1,10‐phenanthroline ligands and their anticancer activity toward human cancer cell lines investigated. The complexes were characterized by infrared (IR) spectra, elemental analysis, and X‐ray crystallography. The interaction of the complexes with CT‐DNA was investigated by UV–vis absorption and fluorescence spectroscopies, and cyclic voltammetry; cell viability (%) was studied using the absorbance amount of the samples. The interaction mode of the complexes with DNA is electrostatic, and the complexes displayed good anticancer activity against HCT 116 (human colorectal cancer cells) and MDA‐MB‐231 (MD Anderson‐metastatic breast) cell lines with best IC50 amount of 11.31 ± 0.74 μM for Z9. The results showed that the nature of the nitrogen‐donor ligand is very effective in the anticancer activity of the complexes.
Granitic quarry waste as a dual functional filler for high density polyethylene‐based composites: Mechanical and microwave absorbing properties
Authors: de Moura Luanna C. R. , Soares Bluma G. , Indrusiak Tamara , Neumann Reiner , Tavares Luís Marcelo
Published: September 2021

Cost‐effective polymeric composites were successfully prepared by melt blending granitic quarry waste (GQW) with high‐density polyethylene (HDPE). The GQW is a waste generated during the production of manufacture fine aggregates (MFA) from crushed gneiss rock and contains significant amount of mica with iron in its structure. Different sieving and milling procedures were employed. The materials were characterized by mechanical and dynamic‐mechanical properties and scanning electron microscopy. Moreover, the influence of the GQW on the microwave absorbing properties in the X‐band frequency range was investigated. The presence of mica and iron compound in the GQW provides a dual function to the filler: toughening agent with microwave absorbing capacity. Indeed, the addition of 5 wt% of GQW previously sieved and milled by dry or wet‐grinding approach resulted in composites with outstanding toughness, modulus and elongation at break. Simulated RL studies revealed electro‐magnetic attenuation of −25 dB at 8.7 GHz. Such successful use of a waste generated in the production of a concentrate (MFA) not only contributes to the economics of the quarrying operation, but also to its environmental sustainability, since it replaces disposal of this product, which could lead to dust emissions, given its fine size and low moisture content.
Influence of rigid particles on thermal conductivity enhancement of polydimethylsiloxane composite during spatial confining forced network assembly
Authors: Zhang Xiaowen , Guo Yang , Zhang Hao , Guo Mengli , Liu Ying , Wu Daming , Chen Ning , Sun Jingyao
Published: September 2021

In order to meet the heat dissipation requirements of electronic equipment, a variety of methods for preparing thermally conductive polymer composites have been proposed. In this article, highly thermal conductive polydimethylsiloxane (PDMS) composites were prepared by combining the spatial confining forced network assembly (SCFNA) method with adding rigid particles (RPs). The orthogonal experiments were designed to verify the effects of short carbon fiber (SCF) content, glass bubble (GB) content, GB particle size and composite thickness on the thermal conductivity (λ) of SCF‐GB/PDMS composite. In addition, the λ and shapes of different RPs (including GB, SiO2, AlN, glass fiber [GF]) also play vital roles in λ enhancements of SCF‐RP/PDMS composites. The mechanical properties of SCF‐RP/PDMS composites were different with various RPs contents, and the SCF‐GB/PDMS composite presented the largest elongation at break (70%) and the best mechanical flexibility. The SCF‐GB/PDMS composite with a low GB content of 5 vol% can not only greatly improve the λ, but also ensure its excellent mechanical properties.
In‐situ polymerization of polyaniline in PDADMAC/PSS complex membranes: Effect of the polyelectrolyte stoichiometry
Authors: Luangaramvej Pimchaya , Wijitsettakun Pisut , Plengplung Pha‐sita , Dubas Stephan Thierry
Published: September 2021

The direct polymerization of a polymer in a polyelectrolyte complex membrane is a quick and simple method to enhance the properties and add functionality to a pre‐formed membrane. Here, polyelectrolyte complex membrane (PECs) of poly (diallyl dimethyl ammonium chloride) (PDADMAC) [P+] and poly (styrene sulfonate) [P−] were modified by the in‐situ polymerization of aniline monomer into polyaniline (PANI). The initial PECs were prepared by the co‐precipitation of polyelectrolytes with various [P+]: [P−] molar ratio and were formed into 100 micron thin membranes by compression molding. The in‐situ polymerization of PANI was achieved by sequential dipping of the PECs in ammonium peroxydisulfate solution to load the oxidant and in the aniline monomer solution to initiate the polymerization. Both the polyelectrolyte stoichiometry and the NaCl concentration used during the formation of the complex were found to have a profound effect on the polymerization reaction. UV–visible spectroscopy, X‐ray diffraction, and infrared spectroscopy were used to characterize the changes in color of the PANI membranes and to confirm the synthesis of PANI. Scanning electron microscopy revealed the presence of a dense coating of PANI at the surface of the PEC.
Effects of interval‐based inpatient treatment for anorexia nervosa: An observational study
Authors: Peters Kathrin , Meule Adrian , Voderholzer Ulrich , Rauh Elisabeth
Published: September 2021

Objective

After inpatient treatment for anorexia nervosa (AN), many patients relapse and need to be readmitted. To obtain a sustained improvement, a pre‐planned multistep inpatient procedure might help to improve the patient's skills in dealing with symptoms and transdiagnostic problems, thus decreasing symptoms of AN. However, no data have been reported for such interval treatment yet. Therefore, this study examined effects of interval treatment in inpatients with AN.

Method

Data of adult women with AN (N = 304) who received inpatient treatment and either received interval treatment (n = 179) or not (n = 125) were analyzed. Of these, 225 patients completed a follow up measurement after an average of 25 months. Treatment outcome variables were body mass index and subscales of the Eating Disorder Inventory‐2 at admission, discharge, and follow up.

Results

Across measurements, the interval treatment group had larger increases in body mass index and larger decreases in drive for thinness and binge/purge symptoms than the no interval treatment group. These differences did not seem to be driven by longer treatment duration.

Discussion

Our data suggest that interval treatment for AN is effective and may even be superior to conventional single inpatient treatment. Given the observational nature of this study, however, controlled studies are necessary to corroborate these findings.
Harnessing P450 Enzyme for Biotechnology and Synthetic Biology
Authors: Zhang Libo , Wang Qian
Published: September 2021

Cytochrome P450 enzymes (P450s, CYPs) catalyze the oxidative transformation of a wide range of organic substrates. Their functions are crucial to xenobiotic metabolism and steroid transformation in humans and other organisms. The enzymes are promising for synthetic biology applications but limited by several drawbacks including low turnover rates, poor stability, the dependance of expensive cofactors and redox partners, and the narrow substrate scope. To conquer these obstacles, emerging strategies including substrate engineering, usage of decoy and decoy‐based small molecules auxiliaries, designing of artificial enzyme cascades and the incorporation of materials have been explored based on the unique properties of P450s. These strategies can be applied to a wide range of P450s and can be combined with protein engineering to improve the enzymatic activities. This minireview will focus on some recent developments of these strategies which have been used to leverage P450 catalysis. Remaining challenges and future opportunities will also be discussed.
On the Weak Binding and Spectroscopic Signature of SARS‐CoV‐2 nsp14 Interaction with RNA
Authors: Hassan Ayaz , Sedenho Graziela C. , Vitale Phelipe A. M. , Oliviera Mona N. , Crespilho Frank N.
Published: September 2021

The SARS‐CoV‐2 non‐structural protein 14 (nsp14), known as exoribonuclease is encoded from the large polyprotein of viral genome and is a major constituent of the transcription replication complex (TRC) machinery of the viral RNA synthesis. This protein is highly conserved among the coronaviruses and is a potential target for the development of a therapeutic drug. Here, we report the SARS‐CoV‐2 nsp14 expression, show its structural characterization, and ss‐RNA exonuclease activity through vibrational and electronic spectroscopies. The deconvolution of amide‐I band in the FTIR spectrum of the protein revealed a composition of 35 % α‐helix and 25 % β‐sheets. The binding between protein and RNA is evidenced from the spectral changes in the amide‐I region of the nsp14, showing protein conformational changes during the binding process. A value of 20.60±3.81 mol L−1 of the binding constant (KD) is obtained for nsp14/RNA complex. The findings reported here can motivate further studies to develop structural models for better understanding the mechanism of exonuclease enzymes for correcting the viral genome and can help in the development of drugs against SARS‐CoV‐2.
The E2 state of FeMoco: Hydride Formation versus Fe Reduction and a Mechanism for H2 Evolution
Authors: Thorhallsson Albert Th. , Bjornsson Ragnar
Published: September 2021

The iron‐molybdenum cofactor (FeMoco) is responsible for dinitrogen reduction in Mo nitrogenase. Unlike the resting state, E0, reduced states of FeMoco are much less well characterized. The E2 state has been proposed to contain a hydride but direct spectroscopic evidence is still lacking. The E2 state can, however, relax back the E0 state via a H2 side‐reaction, implying a hydride intermediate prior to H2 formation. This E2→E0 pathway is one of the primary mechanisms for H2 formation under low‐electron flux conditions. In this study we present an exploration of the energy surface of the E2 state. Utilizing both cluster‐continuum and QM/MM calculations, we explore various classes of E2 models: including terminal hydrides, bridging hydrides with a closed or open sulfide‐bridge, as well as models without. Importantly, we find the hemilability of a protonated belt‐sulfide to strongly influence the stability of hydrides. Surprisingly, non‐hydride models are found to be almost equally favorable as hydride models. While the cluster‐continuum calculations suggest multiple possibilities, QM/MM suggests only two models as contenders for the E2 state. These models feature either i) a bridging hydride between Fe2 and Fe6 and an open sulfide‐bridge with terminal SH on Fe6 (E2‐hyd) or ii) a double belt‐sulfide protonated, reduced cofactor without a hydride (E2‐nonhyd). We suggest both models as contenders for the E2 redox state and further calculate a mechanism for H2 evolution. The changes in electronic structure of FeMoco during the proposed redox‐state cycle, E0→E1→E2→E0, are discussed.
Efficient Near‐Infrared Electrochemiluminescence from Au18 Nanoclusters
Authors: Hesari Mahdi , Ding Zhifeng
Published: September 2021

Bright, near‐infrared electrochemiluminescence (NIR–ECL) of Au18 nanoclusters is reported herein. Spooling ECL and photoluminescence spectroscopy were used to track and link NIR emissions at 832 and 848 nm to three emissive species, Au180*, Au181+* and Au182+*, with a considerably high ECL efficiency of 5.5 relative to that of the gold standard Ru(bpy)32+/TPrA (with 5–6 % reported ECL efficiency). The unprecedentedly high efficiency is due to the overlapped oxidation potentials of Au180 and tri‐n‐propylamine as co‐reactant, the exposed facets of Au180 gold core, and electrocatalytic loops. These discoveries will add a new member to the efficient NIR‐ECL gold nanoclusters family and bring more potential applications.
Life‐years lost due to cancer among solid organ transplant recipients in the United States, 1987 to 2014
Authors: Noone Anne‐Michelle , Pfeiffer Ruth M. , Schaubel Douglas E. , Dorgan Joanne F. , Magder Laurence S. , Bromberg Jonathan S. , Lynch Charles F. , Morris Cyllene R. , Pawlish Karen S. , Engels Eric A.
Published: September 2021

Background

Solid organ transplant recipients have an elevated risk of cancer. Quantifying the life‐years lost (LYL) due to cancer provides a complementary view of the burden of cancer distinct from other metrics and may identify subgroups of transplant recipients who are most affected.

Methods

Linked transplant and cancer registry data were used to identify incident cancers and deaths among solid organ transplant recipients in the United States (1987‐2014). Data on LYL due to cancer within 10 years posttransplant were derived using mean survival estimates from Cox models.

Results

Among 221,962 transplant recipients, 13,074 (5.9%) developed cancer within 10 years of transplantation. During this period, the mean LYL due to cancer were 0.16 years per transplant recipient and 2.7 years per cancer case. Cancer was responsible for a loss of 1.9% of the total life‐years expected in the absence of cancer in this population. Lung recipients had the highest proportion of total LYL due to cancer (0.45%) followed by heart recipients (0.29%). LYL due to cancer increased with age, from 0.5% among those aged birth to 34 years at transplant to 3.2% among those aged 50 years and older. Among recipients overall, lung cancer was the largest contributor, accounting for 24% of all LYL due to cancer, and non‐Hodgkin lymphoma had the next highest contribution (15%).

Conclusions

Transplant recipients have a shortened lifespan after developing cancer. Lung cancer and non‐Hodgkin lymphoma contribute strongly to LYL due to cancer within the first 10 years after transplant, highlighting opportunities to reduce cancer mortality through prevention and screening.
Anion⋅⋅⋅Anion Interactions Involving σ‐Holes of Perrhenate, Pertechnetate and Permanganate Anions
Authors: Daolio Andrea , Pizzi Andrea , Terraneo Giancarlo , Frontera Antonio , Resnati Giuseppe
Published: September 2021

In this communication experimental and theoretical results are reported affording strong evidence that interactions between electron rich atoms and the metal of tetroxide anions of group 7 elements are a new case of attractive and σ‐hole interactions. Single crystal X‐ray analyses, molecular electrostatic potentials, quantum theory of atoms‐in‐molecules, and noncovalent interaction plot analyses show that in crystalline permanganate and perrhenate salts the metal in Mn/ReO4− anion can act as electron acceptors, the oxygen of another Mn/ReO4− anion can act as the donor and supramolecular anionic dimers or polymers are formed. The name matere bond (MaB) is proposed to categorize these noncovalent interactions and to differentiate them from the classical metal‐ligand coordination bond.
Influence of Reaction Conditions on Hydrothermal Carbonization of Fructose
Authors: Modugno Pierpaolo , Titirici Maria‐Magdalena
Published: September 2021

Hydrothermal carbonization is a powerful way to convert cellulosic waste into valuable platform chemicals and carbonaceous materials. In this study, to optimize the process, fructose was chosen as the carbon precursor and the influence of reaction time, acid catalysis, feed gas and pressure on the conversion products is evaluated. 5‐hydroxymethylfurfural (HMF) is produced in high amounts in relatively short time. Both strong and weak acids accelerate fructose conversion. Levulinic acid (LevA) formation is faster than that of hydrothermal (HT) carbon in acidic conditions. Strong acid catalysts should be considered to target preferentially LevA production, whereas milder conditions should be preferred for HMF production. Moreover, a slight initial overpressure of the reactor is always beneficial in terms of conversion. FT‐IR and 13C ss‐NMR spectroscopy and SEM showed that HT carbon evolves through time from a furanic‐based structure with alkylic linkers to an increasingly cross‐linked condensed structure. MALDI‐ToF mass spectrometry showed the existence of a series of oligomers in a mass range within 650 Da and 1500 Da formed by condensation of repeating units.
Intelligent‐Routing Algorithm for wireless body area networks (I‐RAW)
Authors: Sharma Smita , Mishra V M , Tripathi M M
Published: September 2021

The progressive strides in the exploration of sensing technology and the potential use of electrical devices have rendered a promising technology, termed as Wireless Body Area Networks (WBANs). This technology has rendered competency to reform healthcare and making available ubiquitous health care support to remotely located patients. However, the sensor nodes which are embedded on or underneath the body of the patients to measure multifaceted physiological parameters are suffered from the limited battery constraints. In this paper, to address this issue, we propose Intelligent‐Routing Algorithm for WBANs (I‐RAW) to elongate life period of these sensor nodes. The two sinks are located on the front and back side of the patient's body that collects data from the sensor nodes which form clusters and forward the data through the cluster head (CH). We apply Tunicate Swarm Algorithm (TSA) for selection of CH which considers the essential parameters namely, residual energy, network's average energy, distance of node from the sink, path loss model, and energy consumption rate. The use of two sinks in WBAN mitigate hot‐spot problem in the network by avoiding the multi‐hop communication. The simulation results show that I‐RAW improves stability period and network operational period by 37.7% and 42.7%, respectively, as compared to Dual Sink approach using Clustering in Body area network (DSCB) protocol, respectively. Further, I‐RAW also shows supreme performance for various performance metrics as compared to other state‐of‐the‐art protocols.
On the capacity region of the multiple access half‐duplex relay channel
Authors: Al‐Qudah Zouhair , Alrashdan Mohd H. S. , Darabkh Khalid A.
Published: September 2021

In this paper, we consider the transmission over multiple access relay channel (MARC) in which the relay operates in half‐duplex mode. The main contribution of this paper is establishing the capacity of the multiple access half‐duplex relay channel (MAHRC). Toward achieving this goal, we first derive a new achievable rate region. While deriving the achievable rate region, well‐known encoding and decoding schemes, which are used for transmission and reception over the degraded broadcast channel and the multiple access channel, are used. In this transmission scheme, the transmission from the two sources via the half‐duplex relay, to the destination, is split into two phases. Afterwards, an outer bound to the transmission over the discrete memoryless MAHRC is developed. Consequently, we show that the achievable rate region matches the outer bound and therefore the capacity region is formed. Further, the capacity region is extended to the case of Gaussian channel. Additionally, many numerical examples are shown to validate our theoretical derivations. In particular, these numerical examples show that the achievable rate region, and then the capacity, that we derive is larger than the well‐known results in the literature.