bluuebunny/crossref_metadata_2025 huggingface dataset:
Os conselhos territoriais quilombolas no estado da Bahia: mecanismos para um processo de controle social e governança territorial
Authors: Conceição Pedreira George , Cassiano de Araújo Cristiano
Published: December 2018

Os Conselhos Territoriais Quilombolas são uma iniciativa da SEPROMI-BA, Secretaria Estadual para a Promoção da Igualdade Racial, e tem como objetivo a construção de espaços participativos e deliberativos onde as comunidades quilombolas possam se organizar, defender e reivindicar seus interesses e necessidades; em especial, seu acesso às políticas e a programas públicos, contemplando assim o conceito de governança política por meio de um processo de controle social no âmbito do território baiano. Este processo, por sua vez, proporciona inúmeros desafios e perspectivas na construção cultural e política dessas práticas democráticas, com vistas à valorização do povo negro, de suas raízes e da edificação de novas expectativas acerca do planejamento de seus territórios. É por meio desta perspectiva que se introduz a discussão que orbita o presente artigo: a adição da categoria espacial ao conceito de governança, neste caso, imaculado no conceito de Governança Territorial, cujo imbricamento ao conceito-chave oriundo da Ciência Política constrói-se a partir da interpretação que tal capacidade participativa e deliberativa também auxilia uma sociedade organizada territorialmente na gestão dos assuntos públicos a partir do envolvimento conjunto e cooperativo dos atores sociais, econômicos e institucionais, enfatizando, assim, a espacialização da governança e do controle social.

Abstract

THE QUILOMBOLAS TERRITORIAL COUNCILS IN THE STATE OF BAHIA: MECHANISMS FOR A PROCESS OF SOCIAL CONTROL AND TERRITORIAL GOVERNANCE

The Quilombola Territorial Councils are an initiative of SEPROMI-BA, the State Secretariat for the Promotion of Racial Equality, and its objective is the construction of participatory and deliberative spaces where quilombola communities can organize, defend and vindicate their interests and needs; in particular, their access to public policies and programs, thus contemplating the concept of political governance through a process of social control within the territory of Bahia. This process, on the other hand, presents numerous challenges and perspectives in the cultural and political construction of these democratic practices, with a view to valorizing black people, their roots and building new expectations about the planning of their territories. It is from this perspective that the discussion that orbits the present article is introduced: the addition of the spatial category to the concept of governance, in this case, immaculate in the concept of Territorial Governance, whose imbrication to the key concept originating from Political Science is constructed to form the interpretation that such participatory and deliberative capacity also helps a society organized territorially in the management of public affairs from the joint and cooperative involvement of social, economic and institutional actors, emphasizing the spatialization of governance and social control.
Compatibilidade geomórfica e identificação dos padrões de uso e cobertura da terra da Bacia do riacho do Tigre
Authors: Gomes Fábio Vitorino , Souza Jonas Otaviano Praça de
Published: December 2018

Atualmente muitas pesquisas são desenvolvidas na busca de um acompanhamento mais próximo dos problemas detectados nas regiões semiáridas do nordeste brasileiro. O acompanhamento de áreas com potencial agrícola, ou qualquer outro tipo de atividade produtiva nessas regiões vem se tornando mais frequente uma vez que essas regiões necessitam de um monitoramento mais presente deste tipo de atividade e também um melhor planejamento do manejo adequado da terra. Baseado nisto, o zoneamento ambiental torna-se um instrumento importante para classificação de áreas, com procedimentos diversos quanto à análise do uso e da cobertura da terra e dos comportamentos geomórficos. No geral o que se objetiva nesse artigo é destacar a relação entre o uso e o relevo da Bacia do riacho do Tigre - PB, dando ênfase em como os compartimentos do relevo interagem com os tipos de uso do solo e identificar os níveis de compatibilidade geomórfica através da predisposição litológica interpolada com os elementos topográficos. Os resultados mostraram uma área de uso agrícola 80% compatível, 18% moderadamente compatível e 2% incompatível de acordo com o gradiente do terreno encontrado na região.

Abstract

GEOMORPHIC COMPATIBILITY AND IDENTIFICATION OF USE PATTERNS OF THE BASIN LAND COVER TIGER RILL

Many researches are developed in search of a closer follow-up of the problems detected in the semi-arid regions of northeastern Brazil. The monitoring of areas with agricultural potential, or any other type of production activity in these regions where they become more frequent since the regions need a monitoring and present this type of activity and also a better planning of the land management. Based on this, the environmental zoning becomes an important instrument for the classification of areas, where there are different procedures regarding the analysis of land use and coverage and geomorphic behaviors. In general, what refers to this aspect is a relationship between the use and relief of the tiger creek basin - PB, given as the relief comparisons that interact with the types of soil use and identify the levels of compatibility Geomorphic by means of the lithological predisposition interpolated with the topographic elements. The results showed an agricultural use area 80% compatible 18% moderately compatible and 2% incompatible according to the terrain found in the region.
Differential Effects of Adult Salmon Lice Lepeophtheirus salmonis on Physiological Responses of Sockeye Salmon and Atlantic Salmon
Authors: Long Amy , Garver Kyle A. , Jones Simon R. M.
Published: December 2018

The salmon louse Lepeophtheirus salmonis, a type of sea lice (family Caligidae), is enzootic in marine waters of British Columbia and poses a health risk to both farmed Atlantic Salmon Salmo salar and wild Pacific salmon Oncorhynchus spp. At the adult stage, sea lice infections can often result in severe cutaneous lesions in their salmonid hosts. To evaluate and compare the physiological consequences of adult L. salmonis infections, smolts of Atlantic Salmon and Sockeye Salmon O. nerka were exposed to 2 (low), 6 (medium), or 10 (high) adult female lice/fish. Mean lice abundance decreased over time in all groups. Skin disruption due to parasite infection was observed in both species. Plasma samples were collected from infected fish and uninfected controls at 1, 3, 5, and 7 d postinfection and measured for indicators of osmoregulatory function and stress. Sockeye Salmon, regardless of L. salmonis exposure level, showed a rapid onset of elevated osmolality and sodium and chloride ion concentrations which were sustained until 7 d postinfection when values returned to levels comparable with the unexposed controls. Conversely, these effects were not measured in Atlantic Salmon. Additionally, differential host effects in blood glucose levels were observed, with Sockeye Salmon displaying immediate elevation in glucose. Relative to Atlantic Salmon, infection with L. salmonis caused a profound physiological impact to Sockeye Salmon characterized by loss of osmoregulatory integrity and a stress response. This work provides the first comprehensive report of the physiological consequences of infections with adult L. salmonis in Sockeye Salmon smolts and helps to further define the mechanisms of susceptibility in this species.
Slower alpha rhythm associates with poorer seizure control in epilepsy
Authors: Abela Eugenio , Pawley Adam D. , Tangwiriyasakul Chayanin , Yaakub Siti N. , Chowdhury Fahmida A. , Elwes Robert D. C. , Brunnhuber Franz , Richardson Mark P.
Published: December 2018

Objective

Slowing and frontal spread of the alpha rhythm have been reported in multiple epilepsy syndromes. We investigated whether these phenomena are associated with seizure control.

Methods

We prospectively acquired resting‐state electroencephalogram (EEG) in 63 patients with focal and idiopathic generalized epilepsy (FE and IGE) and 39 age‐ and gender‐matched healthy subjects (HS). Patients were divided into good and poor (≥4 seizures/12 months) seizure control groups based on self‐reports and clinical records. We computed spectral power from 20‐sec EEG segments during eyes‐closed wakefulness, free of interictal abnormalities, and quantified power in high‐ and low‐alpha bands. Analysis of covariance and post hoc t‐tests were used to assess group differences in alpha‐power shift across all EEG channels. Permutation‐based statistics were used to assess the topography of this shift across the whole scalp.

Results

Compared to HS, patients showed a statistically significant shift of spectral power from high‐ to low‐alpha frequencies (effect size g = 0.78 [95% confidence interval 0.43, 1.20]). This alpha‐power shift was driven by patients with poor seizure control in both FE and IGE (g = 1.14, [0.65, 1.74]), and occurred over midline frontal and bilateral occipital regions. IGE exhibited less alpha power shift compared to FE over bilateral frontal regions (g = −1.16 [−0.68, −1.74]). There was no interaction between syndrome and seizure control. Effects were independent of antiepileptic drug load, time of day, or subgroup definitions.

Interpretation

Alpha slowing and anteriorization are a robust finding in patients with epilepsy and might represent a generic indicator of seizure liability.
Organic Electrochemical Transistor Arrays for In Vitro Electrophysiology Monitoring of 2D and 3D Cardiac Tissues
Authors: Gu Xi , Yeung Sin Yu , Chadda Akriti , Poon Ellen Ngar Yun , Boheler Kenneth R. , Hsing I.‐Ming
Published: December 2018

Here, a multichannel organic electrochemical transistor (OECT) array is reported for electrophysiological monitoring and mapping of action potential propagation of a wide range of cardiac cells, including cell lines, primary cell lines, and human‐sourced stem cell derivatives in 2D and 3D structures. The results suggest that the ability to exploit this OECT‐based platform to map 2D action potential propagation provides a viable strategy to better characterize cardiac cells in response to various chronotropic drugs. The effects of chronotropic agents Isoproterenol and Verapamil on cardiac tissues validate the utility of OECT for drug screening capability, and a preliminary demonstration of a 64‐channel OECT array to monitor the cardiac action potentials for better spatial resolution is presented. The study demonstrates that OECT will be a viable and versatile platform for applications in medical and pharmacological industries.
Role of Additives in Enhancing the Rheological Properties of Magnetorheological Solids: A Review
Authors: Ahmad Khairi Muntaz Hana , Mazlan Saiful Amri ,   Ubaidillah , Choi Seung‐Bok , Abdul Aziz Siti Aishah , Mohamad Norzilawati , Hapipi Norhiwani Mohd , Nordin Nurazmah
Published: December 2018

During the last two decades, magnetorheological (MR) materials have attracted a significant amount of attention because of their tremendous potential for engineering applications. This review focuses on the role of various additives in enhancing the magnetic field‐dependent rheological characteristics of solid and thixotropic matrice‐based MR materials (hereafter referred to as MR solids). Typically, MR solids consist of solid or semi‐solid matrices filled with magnetizable particles. However, additives need to be used to improve their performance such as the MR effect. This parameter is typically determined by the field‐dependent dynamic modulus. Three different groups of additives would be introduced in the review namely plasticizers, carbon‐ and chromium‐based additives. Compared to particles in the common matrix without a softener, those in matrices with additives which act as matrix softeners will be aligned easier during curing. In fact, the interfaces bonding between matrix‐particles would be improved that subsequently enhanced the magnetically induced viscoelastic properties of MRE. In this review, the influences of several additives on the MR effect of various MR solids including MR elastomers, MR greases, and MR gels, which are recognized as efficient smart materials for practical applications in various engineering fields, are surveyed and discussed.
Processing Magnesium and Its Alloys by High‐Pressure Torsion: An Overview
Authors: Figueiredo Roberto B. , Langdon Terence G.
Published: December 2018

Magnesium and its alloys have attracted significant attention in recent years because they display high strength‐to‐density ratios, they are biodegradable and they provide a potential for hydrogen storage. Many investigations have examined the effect of high‐pressure torsion processing on the microstructures and properties of these materials so that numerous reports are now available. This overview provides a summary of the observations reported to date on the structure and mechanical property evolution including the nature of grain refinement, the grain boundary misorientation distributions, texture evolution, and the minimum grain size. For convenience, the mechanical properties are separated into hardness, tensile behavior, and superplastic properties. It is shown that the mechanism of grain refinement differs from other metallic materials processed by severe plastic deformation but high strength may be achieved in magnesium alloys and exceptional ductility in pure magnesium. Hydrogen storage and corrosion behavior are also examined together with a discussion of recent attempts to produce magnesium‐based nanocomposites through processing by high‐pressure torsion.
Mixed Dimensional 2D/3D Hybrid Perovskite Absorbers: The Future of Perovskite Solar Cells?
Authors: Krishna Anurag , Gottis Sébastien , Nazeeruddin Mohammad Khaja , Sauvage Frédéric
Published: December 2018

The cost‐effective processability and high efficiency of the organic–inorganic metal halide perovskite solar cells (PSCs) have shown tremendous potential to intervene positively in the generation of clean energy. However, prior to an industrial scale‐up process, there are certain critical issues such as the lack of stability against over moisture, light, and heat, which have to be resolved. One of the several proposed strategies to improve the stability that has lately emerged is the development of lower‐dimensional (2D) perovskite structures derived from the Ruddlesden–Popper (RP) phases. The excellent stability under ambient conditions shown by 2D RP phase perovskites has made the scalability expectations burgeon since it is one of the most credible paths toward stable PSCs. In this review, the 2D/3D mixed system for photovoltaics (PVs) is elaborately discussed with the focus on the crystal structure, optoelectronic properties, charge carrier dynamics, and their impact on the photovoltaic performances. Finally, some of the further challenges are highlighted while outlining the perspectives of 2D/3D perovskites for high‐efficiency stable solar cells.
Role of the Anion on the Transport and Structure of Organic Mixed Conductors
Authors: Cendra Camila , Giovannitti Alexander , Savva Achilleas , Venkatraman Vishak , McCulloch Iain , Salleo Alberto , Inal Sahika , Rivnay Jonathan
Published: December 2018

Organic mixed conductors are increasingly employed in electrochemical devices operating in aqueous solutions that leverage simultaneous transport of ions and electrons. Indeed, their mode of operation relies on changing their doping (oxidation) state by the migration of ions to compensate for electronic charges. Nevertheless, the structural and morphological changes that organic mixed conductors experience when ions and water penetrate the material are not fully understood. Through a combination of electrochemical, gravimetric, and structural characterization, the effects of water and anions with a hydrophilic conjugated polymer are elucidated. Using a series of sodium‐ion aqueous salts of varying anion size, hydration shells, and acidity, the links between the nature of the anion and the transport and structural properties of the polymer are systematically studied. Upon doping, ions intercalate in the crystallites, permanently modifying the lattice spacings, and residual water swells the film. The polymer, however, maintains electrochemical reversibility. The performance of electrochemical transistors reveals that doping with larger, less hydrated, anions increases their transconductance but decreases switching speed. This study highlights the complexity of electrolyte‐mixed conductor interactions and advances materials design, emphasizing the coupled role of polymer and electrolyte (solvent and ion) in device performance.
Durable Ultraflexible Organic Photovoltaics with Novel Metal‐Oxide‐Free Cathode
Authors: Jiang Zhi , Fukuda Kenjiro , Huang Wenchao , Park Sungjun , Nur Roda , Nayeem Md. Osman Goni , Yu Kilho , Inoue Daishi , Saito Masahiko , Kimura Hiroki , Yokota Tomoyuki , Umezu Shinjiro , Hashizume Daisuke , Osaka Itaru , Takimiya Kazuo , Someya Takao
Published: December 2018

Flexible and stretchable organic photovoltaics (OPVs) are promising as a power source for wearable devices with multifunctions ranging from sensing to locomotion. Achieving mechanical robustness and high power conversion efficiency for ultraflexible OPVs is essential for their successful application. However, it is challenging to simultaneously achieve these features by the difficulty to maintain stable performance under a microscale bending radius. Ultraflexible OPVs are proposed by employing a novel metal‐oxide‐free cathode that consists of a printed ultrathin metallic transparent electrode and an organic electron transport layer to achieve high electron‐collecting capabilities and mechanical robustness. In fact, the proposed ultraflexible OPV achieves a power conversion efficiency of 9.7% and durability with 74% efficiency retention after 500 cycles of deformation at 37% compression through buckling. The proposed approach can be applied to active layers with different morphologies, thus suggesting its universality and potential for high‐performance ultraflexible OPV devices.
3D‐Printed Hydrogel Composites for Predictive Temporal (4D) Cellular Organizations and Patterned Biogenic Mineralization
Authors: McCracken Joselle M. , Rauzan Brittany M. , Kjellman Jacob C. E. , Kandel Mikhail E. , Liu Yu Hao , Badea Adina , Miller Lou Ann , Rogers Simon A. , Popescu Gabriel , Nuzzo Ralph G.
Published: December 2018

Materials chemistries for hydrogel scaffolds that are capable of programming temporal (4D) attributes of cellular decision‐making in supported 3D microcultures are described. The scaffolds are fabricated using direct‐ink writing (DIW)—a 3D‐printing technique using extrusion to pattern scaffolds at biologically relevant diameters (≤ 100 µm). Herein, DIW is exploited to variously incorporate a rheological nanoclay, Laponite XLG (LAP), into 2‐hydroxyethyl methacrylate (HEMA)‐based hydrogels—printing the LAP–HEMA (LH) composites as functional modifiers within otherwise unmodified 2D and 3D HEMA microstructures. The nanoclay‐modified domains, when tested as thin films, require no activating (e.g., protein) treatments to promote robust growth compliances that direct the spatial attachment of fibroblast (3T3) and preosteoblast (E1) cells, fostering for the latter a capacity to direct long‐term osteodifferentiation. Cell‐to‐gel interfacial morphologies and cellular motility are analyzed with spatial light interference microscopy (SLIM). Through combination of HEMA and LH gels, high‐resolution DIW of a nanocomposite ink (UniH) that translates organizationally dynamic attributes seen with 2D gels into dentition‐mimetic 3D scaffolds is demonstrated. These analyses confirm that the underlying materials chemistry and geometry of hydrogel nanocomposites are capable of directing cellular attachment and temporal development within 3D microcultures—a useful material system for the 4D patterning of hydrogel scaffolds.
Quantitative Label‐Free Imaging of 3D Vascular Networks Self‐Assembled in Synthetic Hydrogels
Authors: Kaushik Gaurav , Gil Daniel A. , Torr Elizabeth , Berge Elizabeth S. , Soref Cheryl , Uhl Peyton , Fontana Gianluca , Antosiewicz‐Bourget Jessica , Edington Collin , Schwartz Michael P. , Griffith Linda G. , Thomson James A. , Skala Melissa C. , Daly William T. , Murphy William L.
Published: December 2018

Vascularization is an important strategy to overcome diffusion limits and enable the formation of complex, physiologically relevant engineered tissues and organoids. Self‐assembly is a technique to generate in vitro vascular networks, but engineering the necessary network morphology and function remains challenging. Here, autofluorescence multiphoton microscopy (aMPM), a label‐free imaging technique, is used to quantitatively evaluate in vitro vascular network morphology. Vascular networks are generated using human embryonic stem cell–derived endothelial cells and primary human pericytes encapsulated in synthetic poly(ethylene glycol)‐based hydrogels. Two custom‐built bioreactors are used to generate distinct fluid flow patterns during vascular network formation: recirculating flow or continuous flow. aMPM is used to image these 3D vascular networks without the need for fixation, labels, or dyes. Image processing and analysis algorithms are developed to extract quantitative morphological parameters from these label‐free images. It is observed with aMPM that both bioreactors promote formation of vascular networks with lower network anisotropy compared to static conditions, and the continuous flow bioreactor induces more branch points compared to static conditions. Importantly, these results agree with trends observed with immunocytochemistry. These studies demonstrate that aMPM allows label‐free monitoring of vascular network morphology to streamline optimization of growth conditions and provide quality control of engineered tissues.
A Microwell‐Assisted Multiaptamer Immunomagnetic Platform for Capture and Genetic Analysis of Circulating Tumor Cells
Authors: Dong Zaizai , Tang Chuanhao , Zhao Libo , Xu Jiachao , Wu Yayun , Tang Xiaojun , Zhou Wei , He Rongxiang , Zhao Rong , Xu Li , Zhang Zhen , Fang Xiaohong
Published: December 2018

Detection of circulating tumor cells (CTCs) in peripheral blood is of paramount significance for cancer diagnosis, progress evaluation, and individualized therapy. However, the rareness and heterogeneity of CTCs introduces significant challenges in the capture of cancer cells as well as downstream genetic analysis. In this work, a microwell‐assisted multiaptamer immunomagnetic platform (MMAIP) is proposed for highly efficient capture of CTCs with minimum influence of heterogeneity. Assisted by a microwell chip, the purity of CTCs is greatly improved, thus meeting the requirement of downstream gene analysis. This is, as far as is known, the first aptamer based platform enabling mutation analysis of the captured CTCs from cancer patients, which will contribute to the practical application of aptamers in clinics.
Photon Upconverted Circularly Polarized Luminescence via Triplet–Triplet Annihilation
Authors: Yang Dong , Han Jianlei , Liu Minghua , Duan Pengfei
Published: December 2018

Circularly polarized luminescent materials are of increasing attention due to their potential applications in advanced optical technologies, such as chiroptical devices and optical sensing. Recently, in all reported circularly polarized luminescent materials, high‐energy excitation results in low‐energy or downconverted circularly polarized luminescence (CPL) emission. Although photon upconversion—i.e., the conversion of low‐energy light into higher‐energy emission, with a wide variety of applications—has been widely reported, the integration of photon upconversion and CPL in one chiral system to achieve higher‐energy CPL emission has never been reported. Herein, a brief review is provided of recent achievements in photon‐upconverted CPL via the triplet–triplet annihilation mechanism, focusing on the amplified dissymmetry factor glum through energy transfer process and dual upconverted and downconverted CPL emission through chirality and energy transfer process.
The Theory and Practice Value of Tunable Nanoscale Interlayer of Graphene: Response to Comment on “Tunable Nanoscale Interlayer of Graphene with Symmetrical Polyelectrolyte Multilayer Architecture for Lithium Extraction”
Authors: Zhao Yan , Qian Yukun , Shi Wenhui , Shen Jiangnan
Published: December 2018

Recently, Amir Razmjou has commented on “Tunable Nanoscale Interlayer of Graphene with Symmetrical Polyelectrolyte Multilayer Architecture for Lithium Extraction.” The author focused on the experimental results of the size of tunable nanoscale interlayer but completely ignored the value of the work. Based on the previous works of the phenomenon or theory of the appearance of morphological defects (cracks or pinholes) in graphene membrane, he provided his opinion that the selective separation of cations is due to the appearance of morphological defects (cracks or pinholes). Therefore, he made the conclusion that “the appearance of defects (cracks or pinholes) during bottom‐up synthesis of 2D nanochannels such as graphene oxide‐based membranes played important role in the selective transportation of Li+ ions.” Amir only focused on the interlayer spacing value of around 0.48 nm, which is an average value obtained by experimental measurements, and commented it based on the theories without any analysis of this work. However, he overlooked the theory and practice value of tunable nanoscale interlayer of graphene and many other evidences of this work.
Heat Resisting Metallic Meta‐Skin for Simultaneous Microwave Broadband Scattering and Infrared Invisibility Based on Catenary Optical Field
Authors: Xie Xin , Pu Mingbo , Huang Yijia , Ma Xiaoliang , Li Xiong , Guo Yinghui , Luo Xiangang
Published: December 2018

Metallic skins are widely used in practical engineering owing to their inherent advantages in mechanical and physical characteristics. In this paper, a metasurface skin composed of subwavelength metallic gratings with space‐variant orientations has been proposed to realize exotic electromagnetic properties in microwave and infrared regimes. Equivalent circuit theory and transfer matrix method have been adopted to quantitatively describe the optical fields and dispersion with high accuracy in a catenary form. Based on these analyses, broadband and wide‐angle radar cross‐section (RCS) reduction for microwave has been simulated and experimentally demonstrated. Additional characteristics such as high temperature resistance and low infrared thermal emission are also verified. It is believed that these results may provide a new platform to achieve multifunctional electromagnetic devices and are promising for many applications.
Hafnium Sulfide Nanosheets for Ultrafast Photonic Device
Authors: Yin Jinde , Zhu Fangxiang , Lai Jintao , Chen Hao , Zhang Mengyu , Zhang Jiaqiang , Wang Jintao , He Tingchao , Zhang Bo , Yuan Jianping , Yan Peiguang , Ruan Shuangchen
Published: December 2018

Group IVB transition metal dichalcogenides (TMDs) have attracted significant interests in photoelectronics due to their predictable superior physical properties compared to group VIB (Mo and W) TMDs. However, the nonlinear optical properties and ultrafast photonic devices based on group IVB TMDs remained unexplored so far. Herein, the nonlinear optical absorption of HfS2 nanosheets (NSs) prepared by liquid exfoliation is demonstrated. The usage of HfS2 as a new ultrafast photonic device for high‐energy and ultrashort pulse generation in a fiber laser is reported for the first time. A photonic crystal fiber (PCF) assisted deposition method is presented for the fabrication of an HfS2‐microfiber integrated saturable absorber (SA) device with precisely controllable light–matter interaction, which can benefit the output of the device. The HfS2‐microfiber SA device shows modulation depth of 15.7% and exhibits outstanding ultrashort pulse generation performance with pulse duration of 221.7 fs in the communication band. The experimental results suggest that HfS2 presents highly nonlinear optical absorption and can be developed into an excellent candidate of SA devices for the development of HfS2‐based ultrafast photonics.
Isolable CO2 Adducts of Polarized Alkenes: High Thermal Stability and Catalytic Activity for CO2 Chemical Transformation
Authors: Zhou Hui , Zhang Rui , Lu Xiao‐Bing
Published: December 2018

Various CO2 adducts of tetra‐hydropyrimidin‐2‐ylidene (THPE) derived from the commercially available 1, 5‐diazabicyclo[4.3.0]non‐5‐ene (DBN) were firstly synthesized. X‐ray single crystal analysis revealed the bent geometry of the binding CO2 having an O−C−O angle of 127.50∼129.51° for THPE−CO2 adducts. In situ FTIR experiments demonstrated that THPE−CO2 adducts had unprecedented thermal stability in DMSO, even at 100 °C without decomposition. It was found that the THPE−CO2 adducts were highly active in catalyzing the carboxylative cyclization of CO2 with propargylic alcohols under mild conditions, significantly higher than the previously reported organocatalysts. Various internal and terminal functionalized propargylic alcohols were tolerated in these processes to afford the corresponding α‐alkylidene cyclic carbonates in moderate to good yields with complete (Z)‐stereoselectivity. Isotope labeling, in combination with in‐situ FTIR and stoichiometric experiments, reveal that the catalytic reaction tends to proceed via the THPE−CO2‐mediated basic ionic pair mechanism.

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Copper‐Catalyzed [3+2] Cycloaddition and Interrupted Fischer Indolization to Prepare Polycyclic Furo[2,3‐b]indolines from N‐Aryl Isatin Nitrones and Methylenecyclopropanes
Authors: Wu Si‐Yi , Chen Wei‐Li , Ma Xiao‐Pan , Liang Cui , Su Gui‐Fa , Mo Dong‐Liang
Published: December 2018

Various polycyclic furo[2,3‐b]indolines containing a cyclopropane ring have been prepared in moderate yields with high diastereoselectivity from N‐aryl isatin nitrones and methylenecyclopropanes using a copper‐catalyzed [3+2] cycloaddition and subsequent interrupted Fischer indolization strategy under mild reaction conditions. The obtained furo[2,3‐b]indolines were easily converted to piperidinone‐fused furo[2,3‐b]indolines by selective [1,3]‐rearrangement through N−O bond cleavage. Finally, two chiral polycyclic furo[2,3‐b]indolines were obtained by chiral auxiliary control.

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Co(III)‐Catalyzed [4+1] Annulation of Amides with Allenes via C−H Activation
Authors: Boobalan Ramadoss , Santhoshkumar Rajagopal , Cheng Chien‐Hong
Published: December 2018

A Co(III)‐catalyzed [4+1] annulation of amides with allenes to synthesize isoindolone and 1,5‐dihydro‐pyrrol‐2‐one derivatives is reported. A wide range of aromatic and vinylic amides react with allenes to give the corresponding annulation products in good to excellent yields. The mechanistic studies strongly support that the catalytic reaction proceeds through an amide‐directed C−H activation, followed by carbocobaltation of allene, β‐hydride elimination, and an intramolecular 1,2‐hydroamination.

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Direct Assembly of Polysubstituted Furans via C(sp3)−H Bond Functionalization by Using Dimethyl Sulfoxide as a Dual Synthon
Authors: Liu Yufeng , Hu Yuqun , Cao Zhongzhong , Zhan Xi , Luo Weiping , Liu Qiang , Guo Cancheng
Published: December 2018

An unusual I2‐mediated triple C(sp3)−H functionalization reaction between aryl methyl ketones and dimethyl sulfoxide to form polysubstituted furans has been developed. In this transformation, dimethyl sulfoxide functions as a dual synthon via C(sp3)−H functionalization with formation of two C−C bonds, one C−O bond, and one C−S bond in a one‐step process. Iodine is crucial as promoter of the reaction, by which a number of ketones could be converted easily into 2,4,5‐trisubstituted furans. This provides an extremely simple and expeditious approach to high‐value‐added, biologically significant O‐heterocycles. Based on preliminary experiments, a plausible mechanism is proposed.

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Enamines as Surrogates of Alkyl Carbanions for the Direct Conversion of Secondary Amides to α‐Branched Ketones
Authors: Liu Yong‐Peng , Wang Shu‐Ren , Chen Ting‐Ting , Yu Cun‐Cun , Wang Ai‐E , Huang Pei‐Qiang
Published: December 2018

A direct transformation of secondary amides into α‐branched ketones with enamines as soft alkylation reagents was developed. In this reaction, enamines serve as surrogates of alkyl carbanions, rather than the conventional enolates equivalents in the Stork's reactions, which allowed for the easy introduction of alkyl groups with electrophilic functional groups. In the presence of 4 Å molecular sieves, the method can be extended to the one‐pot coupling of secondary amides with aldehydes to yield ketones.

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Enantioselective Synthesis of CF3‐Containing 3,2’‐Pyrrolidinyl Spirooxindoles and Dispirooxindoles via Thiourea‐Catalyzed Domino Michael/Mannich [3+2] Cycloaddition Reactions
Authors: Lin Ye , Song Yong‐Xing , Du Da‐Ming
Published: December 2018

An efficient and practical organocatalytic asymmetric domino Michael/Mannich [3+2] cycloaddition of N‐2,2,2‐trifluoroethylisatin ketimines and arylidene azlactones by using a hydroquinine‐derived thiourea as the catalyst has been disclosed. Under mild conditions, a broad range of CF3‐containing 3,2’‐pyrrolidinyl spirooxindole/ dispirooxindole derivatives bearing four adjacent stereogenic centers including two vicinal spiro quaternary chiral centers were obtained in high yields (up to 99% yield) with excellent diastereoselectivities (>20:1 dr, in all case) and enantioselectivities (up to >99% ee).

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Ion Conductivity Enhancement in Anti‐Spinel Li3OBr with Intrinsic Vacancies
Authors: Hussain Fiaz , Li Pai , Li Zhenyu , Yang Jinlong
Published: December 2018

Solid electrolytes are expected to play an important role in modern electrochemical energy storage technologies. However, it is still very challenging to achieve a high Li‐ion conductivity in solid electrolytes. In this study, an intrinsic vacancy induced ion conductivity enhancement in a recently synthesized anti‐spinel structure of Li3OBr compared with its anti‐perovskite phase is reported. With a high stability, the intrinsic defective structure of anti‐spinel Li3OBr contains a high concentration of octahedral vacancies. Ab initio molecular dynamic simulations confirm that octahedral vacancies can lead to an extraordinarily high Li mobility (0.136 mS cm−1 at room temperature) in anti‐spinel Li3OBr. Such an ion conductivity enhancement mechanism opens a new avenue in solid electrolyte material design.
Tribo‐Induced Structural Transformation and Lubricant Dissociation at Amorphous Carbon–Alpha Olefin Interface
Authors: Li Xiaowei , Wang Aiying , Lee Kwang‐Ryeol
Published: December 2018

Amorphous carbon (a‐C) combined with a fluid lubricant is capable of providing an ultra‐low friction state and thus achieving long lifetime and reliable operation. However, the understanding of the atomistic process occurring at the sliding friction interfaces, especially the interfacial structure transformation and lubricant dissociation at different contact states, is still not well understood. Here, using reactive molecular dynamics simulation, the friction behavior of a self‐mated a‐C system composited with different alpha olefins (AOs) as lubricants is comparatively investigated, and the results present that due to the co‐existence of tribo‐induced thermal and shearing effects, AOs exhibit different physicochemical behaviors at the a‐C–a‐C interface compared to that at the a‐C surface. Although introducing AOs into a self‐mated a‐C system reduces the friction coefficient, its efficiency strongly relies on the AO variety and contact pressure. The pressure‐driven dissociation of AOs passivates the friction interface, resulting in the evolution of the primary friction mechanism from hydrodynamic lubrication to interfacial passivation that is not accessible by experimental characterization. The corresponding scission sites of different AOs are demonstrated, which enriches the fundamental understanding on sliding friction behavior and offers a comprehensive design criterion for lubricants (viscosity, chain length, and bond saturated states) and a‐C to achieve nearly frictionless sliding interface.
Preparation and absorption properties of poly (acrylic acid‐co‐acrylamide)/graphite oxide superabsorbent composite
Authors: Zhu Linhui , Wang Fangyuan , Liu Yu , Tang Hongduo , Guan Chengdong
Published: December 2018

Poly (acrylic acid‐co‐acrylamide)/graphite oxide (P (AA‐co‐AM)/GO) superabsorbent composite was prepared by solution intercalation polymerization of acrylic acid (AA), acrylamide (AM), and graphite oxide (GO). The composite was characterized by Fourier transform infrared spectroscopy, powder X‐ray diffraction, scanning electron microscopy, transmission electron microscope, thermogravimetric analysis , and differential scanning calorimetry. The effect of reaction conditions, including the mass ratio of monomers, dosages of cross‐linker, initiator, and GO as well as the neutralization degree of AA, on water and saline absorption was studied. Water retention properties of the composite were also discussed. It showed that interactions between GO and P (AA‐co‐AM) copolymer were the intermolecular hydrogen bonds. Thermal stabilities of the composite could be improved by the incorporation of GO. Besides, there was a remarkable improvement of absorption capacities owing to the incorporation of GO. Absorption capacities of water and 0.9% NaCl could be improved from 141.7 and 33.6 g/g, respectively, to 809.6 and 131.4 g/g, respectively, as the dosage of GO increased from 0 to 0.1 g. In addition, there was a remarkable improvement of water retention rates. Water retention rates of P(AA‐co‐AM)/GO and P(AA‐co‐AM) were 65.9% and 53.8%, respectively, after drying at 25°C for 8 hr.
3D Printing of Anisotropic Hydrogels with Bioinspired Motion
Authors: Arslan Hakan , Nojoomi Amirali , Jeon Junha , Yum Kyungsuk
Published: December 2018

Motion in biological organisms often relies on the functional arrangement of anisotropic tissues that linearly expand and contract in response to external signals. However, a general approach that can implement such anisotropic behavior into synthetic soft materials and thereby produce complex motions seen in biological organisms remains a challenge. Here, a bioinspired approach is presented that uses temperature‐responsive linear hydrogel actuators, analogous to biological linear contractile elements, as building blocks to create three‐dimensional (3D) structures with programmed motions. This approach relies on a generalizable 3D printing method for building 3D structures of hydrogels using a fugitive carrier with shear‐thinning properties. This study demonstrates that the metric incompatibility of an orthogonally growing bilayer structure induces a saddle‐like shape change, which can be further exploited to produce various bioinspired motions from bending to twisting. The orthogonally growing bilayer structure undergoes a transition from a stretching‐dominated motion to a bending‐dominated motion during its shape transformation. The modular nature of this approach, together with the flexibility of additive manufacturing, enables the fabrication of multimodular 3D structures with complex motions through the assembly of multiple functional components, which in turn consist of simple linear contractile elements.
Matrix Rigidity‐Dependent Regulation of Ca2+ at Plasma Membrane Microdomains by FAK Visualized by Fluorescence Resonance Energy Transfer
Authors: Kim Tae‐Jin , Lei Lei , Seong Jihye , Suh Jung‐Soo , Jang Yoon‐Kwan , Jung Sang Hoon , Sun Jie , Kim Deok‐Ho , Wang Yingxiao
Published: December 2018

The dynamic regulation of signal transduction at plasma membrane microdomains remains poorly understood due to limitations in current experimental approaches. Genetically encoded biosensors based on fluorescent resonance energy transfer (FRET) can provide high spatiotemporal resolution for imaging cell signaling networks. Here, distinctive regulation of focal adhesion kinase (FAK) and Ca2+ signals are visualized at different membrane microdomains by FRET using membrane‐targeting biosensors. It is shown that rigidity‐dependent FAK and Ca2+ signals in human mesenchymal stem cells (hMSCs) are selectively activated at detergent‐resistant membrane (DRM or rafts) microdomains during the cell–matrix adhesion process, with minimal activities at non‐DRM domains. The rigidity‐dependent Ca2+ signal at the DRM microdomains is downregulated by either FAK inhibition or lipid raft disruption, suggesting that FAK and lipid raft integrity mediate the in situ Ca2+ activation. It is further revealed that transient receptor potential subfamily M7 (TRPM7) participates in the mobilization of Ca2+ signals within DRM regions. Thus, the findings provide insights into the underlying mechanisms that regulate Ca2+ and FAK signals in hMSCs under different mechanical microenvironments.
White‐Light‐Emitting Melamine‐Formaldehyde Microspheres through Polymer‐Mediated Aggregation and Encapsulation of Graphene Quantum Dots
Authors: Wu Youshen , Zhang Hui , Pan Aizhao , Wang Qi , Zhang Yanfeng , Zhou Guijiang , He Ling
Published: December 2018

Graphene quantum dot (GQD) encapsulated melamine‐formaldehyde (MF) polymer microspheres with uniform particle size and tunable high‐quality white‐light emissions are prepared via a polymer‐mediated GQD assembly and encapsulation strategy. In solution, GQDs are first aggregated with MF prepolymer through electrostatic interaction and further encapsulated inside the microspheres formed by polymerization of MF prepolymer under acid catalysis and heating. During this process, the aggregated GQDs are fixed in the MF polymer matrix with their emission extended from blue to full visible range, presenting bright white luminescence under ultraviolet excitation. The prepared white‐light‐emitting GQD‐MF microspheres exhibit uniform morphology with an average particle size of 2.0 ± 0.08 µm and their luminescence properties are effectively regulated by the doping concentration of GQDs in the MF polymer matrix. A series of white‐light‐emitting GQD‐MF microspheres with quantum yields from 0.83 to 0.43, Commission Internationale de L'Eclairage coordinates from (0.28, 0.28) to (0.33, 0.32), and color rendering index from 0.75 to 0.88 are obtained with excellent photostability and thermal stability. By dispersing the GQD‐MF microspheres in cross‐linked polydimethylsiloxane matrix, flexible film with dual functions of high‐quality white‐light‐emitting and light diffusion is obtained and successfully applied for white light‐emitting diode fabrication.
Enhanced Thermoelectric Properties for PEDOT:PSS/Undoped Ge Thin‐Film Bilayered Heterostructures
Authors: Lee Dongwook , Zhou Jiawei , Chen Gang , Shao‐Horn Yang
Published: December 2018

Modulation doping is one of the strategies to improve thermoelectric power factors of nanocomposites and thin‐film bilayered heterostructures by effectively increasing electrical conductivity. Here, it is reported that thin‐film heterostructures of heavily doped p‐type organic conducting polymer, poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and undoped thin‐film Ge can enhance thermoelectric power factor by modulation doping. The maximum power factor and Seebeck coefficient of the bilayered heterostructures are 154 µW m−1 K−2 and 398 µV K−1, respectively, corresponding to 47‐fold and 41‐fold increases compared to those of bulk PEDOT:PSS and 64‐fold increase compared to power factor of undoped Ge. The enhancements in power factor and Seebeck coefficient are quantitatively described by the hole transfer from PEDOT:PSS to Ge, which takes into account the band alignment at the interface detected by Kraut's method. Agreement between the simulation and experiment results also implies predictability of thermoelectric performances of nanoscale bilayered heterostructures in general, when band offset, Fermi level, and individual electronic properties are available. This work can be further extended to predict performance of other nanoscale combinations of thermoelectric and other electronic materials in general.
A quantitative study of the structure–activity relationship in hierarchical zeolites using liquid‐phase reactions
Authors: Xu Dandan , Abdelrahman Omar , Ahn Sang Hyun , Guefrachi Yasmine , Kuznetsov Anatoliy , Ren Limin , Hwang Sonjong , Khaleel Maryam , Al Hassan Saeed , Liu Dongxia , Hong Suk Bong , Dauenhauer Paul , Tsapatsis Michael
Published: December 2018

Micro/meso/macroporous (hierarchical) zeolites show remarkable catalytic performance for reactions involving bulky reactants. However, quantitative assessment of the microstructural characteristics contributing to the observed performance remains elusive. Here, structure–activity relationships are established for a set of micro/mesoporous self‐pillared pentasil (SPP) zeolites using two parallel liquid‐phase reactions (benzyl alcohol alkylation and self‐etherification) based on analysis of mass transport and reaction kinetics. A reaction–diffusion mathematical model is developed that quantitatively assigns the catalytic contributions of the external surface and micropores of SPP zeolites for these reactions. In addition, the effect of the zeolite external surface structure on the corresponding catalytic activity is quantitatively assessed by comparing SPP zeolites (with MFI structure) with MCM‐22 (with MWW structure). This work demonstrates that reaction–diffusion modeling allows quantitative description of the catalytic performance of hierarchical zeolites and provides a model reaction to assess nm‐sized characteristic diffusion lengths in MFI. © 2018 American Institute of Chemical Engineers AIChE J, 65: 1067–1075, 2019
Silicon‐grafted Ag/AgX/rGO nanomaterials (X = Cl or Br) as dip‐photocatalysts for highly efficient p‐nitrophenol reduction and paracetamol production
Authors: Attia Yasser A. , Mohamed Yasser M.A.
Published: December 2018

In this work, plasmonic Ag/AgX/rGO (X = Cl or Br) nano‐photocatalysts were grafted with silicon by adding trimethylsilyl chloride as silicon precursor. The synthesized Ag/AgX/rGO‐Si hybrids showed a large improvement of photocatalytic activity towards the synthesis of p‐aminophenol (PAP) as well as paracetamol (acetaminophen; APAP) through the photoreduction of p‐nitrophenol (PNP). The prepared catalysts Ag/AgX/rGO were characterized using SEM, XRD, FTIR and the reduction reaction of p‐nitrophenol was monitored by UV–Vis measurements, GC/MS and 1HNMR data. From the results, it was demonstrated that the rate order of reduction process of the PNP to PAP and to APAP under visible light irradiation of the samples was as follows; Ag/AgBr/rGO‐Si > Ag/AgCl/rGO‐Si > Ag/AgBr/rGO > Ag/AgCl/rGO. The reaction mechanism had been postulated that was supported with the spectroscopic data. In addition, the catalysts were recovered from the reaction medium and re‐used in three cycles that indicated the reusability and stability of the catalysts. This study was featured by the following; i) fast reaction, ii) the reduction of p‐nitrophenol to paracetamol was performed in a facile one‐pot reaction compared to previous approaches that tends to reduce the production cost, and iii) investigations on the catalytic properties of Ag/AgX/rGO in organic transformations open the door to find a benefice of these catalysts in other organic reactions and in the development in the synthesis of pharmaceutical products.