bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tocopherol biosynthesis in Leishmania (L.) amazonensis promastigotes
Authors: Balanco José Mário F. , Sussmann Rodrigo A.C. , Verdaguer Ignasi B. , Gabriel Heloisa B. , Kimura Emilia A. , Katzin Alejandro M. 
Published: February 2019

Leishmaniasis is a neglected disease caused by a trypanosomatid protozoan of the genus Leishmania. Most drugs used to treat leishmaniasis are highly toxic, and the emergence of drug‐resistant strains has been observed. Therefore, new therapeutic targets against leishmaniasis are required. Several isoprenoid compounds, including dolichols or ubiquinones, have been shown to be important for cell viability and proliferation in various trypanosomatid species. Here, we detected the biosynthesis of tocopherol in Leishmania (L.) amazonensis promastigotes in vitro through metabolic labelling with [1‐(n)‐3H]‐phytol. Subsequently, we confirmed the presence of vitamin E in the parasite by gas chromatography–mass spectrometry. Treatment with usnic acid or nitisinone, inhibitors of precursors of vitamin E synthesis, inhibited growth of the parasite in a concentration‐dependent manner. This study provides the first evidence of tocopherol biosynthesis in a trypanosomatid and suggests that inhibitors of the enzyme 4‐hydroxyphenylpyruvate dioxygenase may be suitable for use as antileishmanial compounds.DatabaseThe amino acid sequence of a conserved hypothetical protein [Leishmania mexicana MHOM/GT/2001/U1103] has been deposited in GenBank (CBZ28005.1)
Silicon‐Compatible Photodetectors: Trends to Monolithically Integrate Photosensors with Chip Technology
Authors: Yang Wei , Chen Jiaxin , Zhang Yong , Zhang Yujia , He Jr‐Hau , Fang Xiaosheng 
Published: February 2019

AbstractEncouraged by the increasing requirements of intelligent equipment, silicon integrated circuit–compatible photodetectors that support single‐chip photonic–electronic systems have gained considerable progresses. Advanced materials have resulted in enhanced device performance based on traditional photovoltaic effect and photoconductive effect, and novel device designs have catalyzed new working mechanisms combing rapid photoresponse and high responsivity gain. Surprising applications are developed using monolithic photonic–electronic platforms, and the developing integration strategies keep pace with the developing complementary metal‐oxide‐semiconductor techniques as well as nonsilicon substrates. Here, the recent developments in silicon‐compatible photodetectors, both in device advances and their integration routes, are reviewed. Meanwhile, the progresses, challenges, and possible future directions in this field are discussed and concluded.
On‐Chip Ni–Zn Microbattery Based on Hierarchical Ordered Porous Ni@Ni(OH)2 Microelectrode with Ultrafast Ion and Electron Transport Kinetics
Authors: Hao Zhimeng , Xu Lin , Liu Qin , Yang Wei , Liao Xiaobin , Meng Jiashen , Hong Xufeng , He Liang , Mai Liqiang 
Published: February 2019

AbstractOn‐chip microbatteries have attracted growing attention due to their great feasibility for integration with miniaturized electronic devices. Nevertheless, it is difficult to get both high energy/power densities in microbatteries. An increase in the thickness of microelectrodes may help to boost the areal energy density of device, yet it often leads to terrible sacrifice in its power density due to the longer electron and ion diffusion distances. In this work, a quasi‐solid‐state on‐chip Ni–Zn microbattery is designed based on a hierarchical ordered porous (HOP) Ni@Ni(OH)2 microelectrode, which is developed by an in situ anodizing strategy. The fabricated microelectrode can optimize ion and electron transport simultaneously due to its interconnected ordered macropore–mesopore network and high electron conductivity. As the thickness of microelectrode increases, the areal energy density of HOP Ni@Ni(OH)2 microelectrode shows an ascending trend with negligible sacrifice in power density and rate performance. Impressively, this Ni–Zn microbattery achieves excellent energy/power densities (0.26 mW h cm−2, 33.8 mW cm−2), outperforming most previous reported microenergy storage devices. This study may provide new direction in high‐performance and highly safe microenergy storage units for next‐generation highly integrated microelectronics.
Layer‐Based Heterostructured Cathodes for Lithium‐Ion and Sodium‐Ion Batteries
Authors: Deng Ya‐Ping , Wu Zhen‐Guo , Liang Ruilin , Jiang Yi , Luo Dan , Yu Aiping , Chen Zhongwei 
Published: February 2019

AbstractA critical bottleneck that hinders major performance improvement in lithium‐ion and sodium‐ion batteries is the inferior electrochemical activity of their cathode materials. While significant research progresses have been made, conventional single‐phase cathodes are still limited by intrinsic deficiencies such as low reversible capacity, enormous initial capacity loss, rapid capacity decay, and poor rate capability. In the past decade, layer‐based heterostructured cathodes acquired by combining multiple crystalline phases have emerged as candidates with a huge potential to realize performance breakthrough. Herein, recent studies on the structural properties, electrochemical behaviors, and synthesis route optimizations of these heterostructured cathodes are summarized for in‐depth discussions. Particular attention is paid to the latest mechanism discoveries and performance achievements. This review thus aims to promote a deeper understanding of the correlation between the crystal structure of cathodes and their electrochemical behavior, and offers guidance to design advance cathode materials from the aspect of crystal structure engineering.
Biomimetic Polymer Film with Brilliant Brightness Using a One‐Step Water Vapor–Induced Phase Separation Method
Authors: Zou Weizhi , Pattelli Lorenzo , Guo Jing , Yang Shijia , Yang Meng , Zhao Ning , Xu Jian , Wiersma Diederik S. 
Published: February 2019

AbstractThe scales of the white Cyphochilus beetles are endowed with unusual whiteness arising from the exceptional scattering efficiency of their disordered ultrastructure optimized through millions of years of evolution. Here, a simple, one‐step method based on water vapor–induced phase separation is developed to prepare thin polystyrene films with similar microstructure and comparable optical performance. A typical biomimetic 3.5 µm PS film exhibits a diffuse reflectance of 61% at 500 nm wavelength, which translates into a transport mean free path below 1 µm. A complete optical characterization through Monte Carlo simulations reveals how such a scattering performance arises from the scattering coefficient and scattering anisotropy, whose interplay provides insight into the morphological properties of the material. The potential of bright‐white coatings as smart sensors or wearable devices is highlighted using a treated 3.5 µm film as a real‐time sensor for human exhalation.
Constructing Connected Paths between UiO‐66 and PIM‐1 to Improve Membrane CO2 Separation with Crystal‐Like Gas Selectivity
Authors: Yu Guangli , Zou Xiaoqin , Sun Lei , Liu Baisong , Wang Ziyang , Zhang Panpan , Zhu Guangshan 
Published: February 2019

AbstractMost metal–organic‐framework‐ (MOF‐) based hybrid membranes face the challenge of low gas permeability in CO2 separation. This study presents a new strategy of interweaving UiO‐66 and PIM‐1 to build freeways in UiO‐66‐CN@sPIM‐1 membranes for fast CO2 transport. In this strategy, sPIM‐1 is rigidified via thermal treatment to make polymer voids permanent, and concurrently polymer chains are mutually linked onto UiO‐66‐CN crystals to minimize interfacial defects. The pore chemistry of UiO‐66‐CN is kept intact in hybrid membranes, allowing full utilization of MOF pores and selective adsorption for CO2. Separation results show that UiO‐66‐CN@sPIM‐1 membranes possess exceptionally high CO2 permeability (15433.4–22665 Barrer), approaching to that of UiO‐66‐NH2 crystal (65–75% of crystal‐derived permeability). Additionally, the CO2/N2 permeation selectivity for a representative membrane (23.9–28.6) moves toward that of single crystal (24.6–29.6). The unique structure and superior CO2/N2 separation performance make UiO‐66‐CN@sPIM‐1 membranes promising in practical CO2 separations.
Artificially Reprogrammed Macrophages as Tumor‐Tropic Immunosuppression‐Resistant Biologics to Realize Therapeutics Production and Immune Activation
Authors: Li Chu‐Xin , Zhang Yu , Dong Xue , Zhang Lu , Liu Miao‐Deng , Li Bin , Zhang Ming‐Kang , Feng Jun , Zhang Xian‐Zheng 
Published: February 2019

AbstractTo engineer patient‐derived cells into therapy‐purposed biologics is a promising solution to realize personalized treatments. Without using gene‐editing technology, a live cell‐typed therapeutic is engineered for tumor treatment by artificially reprogramming macrophages with hyaluronic acid‐decorated superparamagnetic iron oxide nanoparticles (HIONs). This nanoparticle‐assisted cell‐reprogramming strategy demonstrates profound advantages, due to the combined contributions from the biological regulation of HIONs and the intrinsic nature of macrophages. Firstly, the reprogrammed macrophages present a substantial improvement in their innate capabilities, such as more effective tumor targeting and more efficient generation of bioactive components (e.g., reactive oxygen species, bioactive cytokines) to suppress tumor growth. Furthermore, this cell therapeutic exhibits cytostatic/proapoptotic effects specific to cancer cells. Secondly, HIONs enable macrophages more resistant to the intratumoral immunosuppressive environment. Thirdly, the macrophages are endowed with a strong ability to prime in situ protumoral M2 macrophages into antitumor M1 phenotype in a paracrine‐like manner. Consequently, a synergistic tumor‐inhibition effect is achieved. This study shows that engineering nanomaterial‐reprogrammed live cells as therapeutic biologics may be a more preferable option to the commonly used approaches where nanomaterials are administrated to induce bioresponse of certain cells in vivo.
A Bioinspired Platform for Effective Delivery of Protein Therapeutics to the Central Nervous System
Authors: Wu Di , Qin Meng , Xu Duo , Wang Lan , Liu Chaoyong , Ren Jie , Zhou George , Chen Chen , Yang Fengmei , Li Yanyan , Zhao Yuan , Huang Ruyi , Pourtaheri Sina , Kang Chunsheng , Kamata Masakazu , Chen Irvin S. Y. , He Zhanlong , Wen Jing , Chen Wei , Lu Yunfeng 
Published: February 2019

AbstractCentral nervous system (CNS) diseases are the leading cause of morbidity and mortality; their treatment, however, remains constrained by the blood–brain barrier (BBB) that impedes the access of most therapeutics to the brain. A CNS delivery platform for protein therapeutics, which is achieved by encapsulating the proteins within nanocapsules that contain choline and acetylcholine analogues, is reported herein. Mediated by nicotinic acetylcholine receptors and choline transporters, such nanocapsules can effectively penetrate the BBB and deliver the therapeutics to the CNS, as demonstrated in mice and non‐human primates. This universal platform, in general, enables the delivery of any protein therapeutics of interest to the brain, opening a new avenue for the treatment of CNS diseases.
Single Layer 2D Crystals for Electrochemical Applications of Ion Exchange Membranes and Hydrogen Evolution Catalysts
Authors: Perez‐Page Maria , Sahoo Madhumita , Holmes Stuart M. 
Published: February 2019

AbstractThe isolation of graphene is considered as the beginning of a new generation of 2D materials and 2D crystals. Because of their particular layered structure, with planar topology and a thickness from single to few atomic layers, which provide them with unique properties, 2D material are expected to have important applications in the next generation of energy systems. Electrochemical energy storage devices such as batteries or supercapacitors have already incorporated these materials as electrodes, electrocatalysts, etc. However, most of the applications reported so far use graphene based materials such as graphene oxide (GO) or reduced graphene oxide (rGO), or different 2D materials in a bulk feature. This review aims to provide an overview of the recent progress in using single layer and few layer 2D materials in electrochemical applications of ion exchange membranes and hydrogen evolution catalysts and their efficacy in these systems.
Dual Protection Layer Strategy to Increase Photoelectrode–Catalyst Interfacial Stability: A Case Study on Black Silicon Photoelectrodes
Authors: Yang Fan , Aguiar Jeffery A. , Fairchild Michael , Vakki Waltteri , Younan Sabrina , Zhou Yinghua , Zhuo Linhai , Gu Jing 
Published: February 2019

AbstractPhotoelectrode degradation under harsh solution conditions continues to be a major hurdle for long‐term operation and large‐scale implementation of solar fuel conversion. In this study, a dual‐layer TiO2 protection strategy is presented to improve the interfacial durability between nanoporous black silicon and photocatalysts. Nanoporous silicon photocathodes decorated with catalysts are passivated twice, providing an intermediate TiO2 layer between the substrate and catalyst and an additional TiO2 layer on top of the catalysts. Atomic layer deposition of TiO2 ensures uniform coverage of both the nanoporous silicon substrate and the catalysts. After 24 h of electrolysis at pH = 0.3, unprotected photocathodes layered with platinum and molybdenum sulfide retain only 30% and 20% of their photocurrent, respectively. At the same pH, photocathodes layered with TiO2 experience an increase in photocurrent retention: 85% for platinum‐coated photocathodes and 91% for molybdenum sulfide–coated photocathodes. Under alkaline conditions, unprotected photocathodes experience a 95% loss in photocurrent within the first 4 h of electrolysis. In contrast, TiO2‐protected photocathodes maintain 70% of their photocurrent during 12 h of electrolysis. This approach is quite general and may be employed as a protection strategy for a variety of photoabsorber–catalyst interfaces under both acidic and basic electrolyte conditions.
Nickel‐Catalyzed C(sp2)−C(sp3) Kumada Cross‐Coupling of Aryl Tosylates with Alkyl Grignard Reagents
Authors: Piontek Aleksandra , Ochędzan‐Siodłak Wioletta , Bisz Elwira , Szostak Michal 
Published: February 2019

AbstractAryl tosylates are an attractive class of electrophiles for cross‐coupling reactions due to ease of synthesis, low price, and the employment of C−O electrophiles, however, the reactivity of aryl tosylates is low. Herein, we report the Ni‐catalyzed C(sp2)−C(sp3) Kumada cross‐coupling of aryl tosylates with primary and secondary alkyl Grignard reagents. The method delivers valuable alkyl arenes by cross‐coupling with challenging alkyl organometallics possessing β‐hydrogens that are prone to β‐hydride elimination and homo‐coupling. The reaction is catalyzed by an air‐ and moisture stable‐Ni(II) precatalyst. A broad range of electronically‐varied aryl tosylates, including bis‐tosylates, underwent this transformation, and many examples are suitable at mild room temperature conditions. The combination of Ar−X cross‐coupling with the facile Ar−OH activation/cross‐coupling strategy permits for orthogonal cross‐coupling with challenging alkyl organometallics. Furthermore, we demonstrate that the method operates with TON reaching 2000, which is one of the highest turnovers observed to date in Ni‐catalyzed cross‐couplings.magnified image
Pd‐Catalyzed Diastereoselective Intramolecular Amide α‐C−H Arylation in Sterically Hindered Monospirooxindole Motifs
Authors: Shukla Dipti , Babu Srinivasarao Arulananda 
Published: February 2019

AbstractThis paper reveals the diastereoselective Pd‐catalyzed intramolecular α‐C(sp3)−H arylation in amides. The intermolecular and intramolecular α‐arylation of tertiary C(sp3)−H bond of carbonyl compounds have been well documented in the literature. Nevertheless, the diastereoselective intramolecular α‐arylation of tertiary C(sp3)−H bond involving sterically hindered spirocyclic carbonyl substrates, especially amides remains a less explored task. Accordingly, we have demonstrated the diastereoselective Pd‐catalyzed intramolecular amide α‐arylation of tertiary C(sp3)−H bond using monospirooxindole‐based carboxamide substrates and construction of various sterically hindered 1,2‐bisspirooxindolopyrrolidines possessing contiguous vicinal quaternary stereocenters with high diastereoselectivity. Monospirooxindole‐based carboxamide substrates suitably positioned with an aryl halide unit and tertiary α‐C−H bond, which were required for investigating the intramolecular α‐C(sp3)−H arylation were assembled via the stereoselective [3+2] cycloaddition of azomethine ylides with acrylamides. The stereochemistry of monospirooxindoles and 1,2‐bisspirooxindolopyrrolidines possessing contiguous vicinal quaternary stereocenters was assigned based on the X‐ray structure analyses of representative compounds.magnified image
Exploring the Biocatalytic Potential of a Self‐Sufficient Cytochrome P450 from Thermothelomyces thermophila
Authors: Fürst Maximilian J. L. J. , Kerschbaumer Bianca , Rinnofner Claudia , Migglautsch Anna K. , Winkler Margit , Fraaije Marco W. 
Published: February 2019

AbstractAmong nature's arsenal of oxidative enzymes, cytochrome P450s (CYPs) catalyze the most challenging reactions, the hydroxylations of non‐activated C−H bonds. Human CYPs are studied in drug development due to their physiological role at the forefront of metabolic detoxification, but their challenging handling makes them unsuitable for application. CYPs have a great potential for biocatalysis, but often lack appropriate features such as high and soluble expression, self‐sufficient internal electron transport, high stability, and an engineerable substrate scope. We have probed these characteristics for a recently described CYP that originates from the thermophilic fungus Thermothelomyces thermophila (CYP505A30), a homolog of the well‐known P450‐BM3 from Bacillus megaterium. CYP505A30 is a natural monooxygenase‐reductase fusion, is well expressed, and moderately tolerant towards temperature and solvent exposure. Although overall comparable, we found the stability of the enzyme's domains to be inverse to P450‐BM3, with a more stable reductase compared to the heme domain. After analysis of a homology model, we created mutants of the enzyme based on literature data for P450‐BM3. We then probed the enzyme variants in bioconversions using a panel of active pharmaceutical ingredients, and activities were detected for a number of structurally diverse compounds. Ibuprofen was biooxidized in a preparative scale whole cell bioconversion to 1‐, 2‐ and 3‐hydroxyibuprofen.magnified image
Multireference Approaches to Spin‐State Energetics of Transition Metal Complexes Utilizing the Density Matrix Renormalization Group
Authors: Roemelt Michael , Pantazis Dimitrios A. 
Published: February 2019

AbstractThe accurate and reliable calculation of different electronic states in transition metal systems is a persistent challenge for theoretical chemistry. The widespread use of density functional theory for computing the relative energies of states with different spin in transition metal complexes not only has not discouraged, but often, owing to its limitations, has motivated the development and refinement of first‐principles wavefunction–based methods, including both single‐reference and multireference approaches. A significant boost for the latter has been the emergence of the density matrix renormalization group (DMRG) as a reliable tool in applied quantum chemistry. By enabling the use of larger active spaces than conventionally possible, DMRG has opened up areas of transition metal chemistry that were previously inaccessible to multireference approaches. The present perspective provides an overview of representative studies that make use of DMRG methods and discusses recent applications to spin‐state energetics of transition metal systems. These range from mononuclear to exchange‐coupled systems that define an important emerging field of DMRG applications. Major achievements are highlighted and potential pitfalls are identified with a view toward future methodological developments as well as extensions in the applicability of DMRG‐based approaches to problems of spin‐state energetics and exchange‐coupling in transition metal chemistry.
Various Threshold Switching Devices for Integrate and Fire Neuron Applications
Authors: Lee Donguk , Kwak Myonghoon , Moon Kibong , Choi Wooseok , Park Jaehyuk , Yoo Jongmyung , Song Jeonghwan , Lim Seokjae , Sung Changhyuck , Banerjee Writam , Hwang Hyunsang 
Published: February 2019

AbstractThis study demonstrates an integrate and fire (I&F) neuron using threshold switching (TS) devices to implement spike‐based neuromorphic system. An I&F neuron can be realized using the hysteric voltage switch characteristics of a TS device. To investigate the effects of various TS devices on neuron behavior, neurons are compared using three different types of TS device: NbO2‐based insulator‐to‐metal transition (IMT) device, B–Te‐based ovonic threshold switching device, and Ag/HfO2‐based atomic‐switching TS device. The results show that the off‐state resistance and switching time of the TS devices determine the leaky/nonleaky characteristics and types of activation function of neuron, respectively. In addition, it is confirmed that the threshold voltage and on‐state resistance of the TS device determine the total power consumption of neuron. Furthermore, the feasibility of the TS devices in a spiking neural network is verified by simulation program with integrated circuit emphasis (SPICE) simulation. This work indicates applicability of TS‐based I&F neuron in neuromorphic hardware application.
Polymer Nanocomposites with Interpenetrating Gradient Structure Exhibiting Ultrahigh Discharge Efficiency and Energy Density
Authors: Jiang Jianyong , Shen Zhonghui , Cai Xingke , Qian Jianfeng , Dan Zhenkang , Lin Yuanhua , Liu Bilu , Nan Ce‐Wen , Chen Longqing , Shen Yang 
Published: February 2019

AbstractPoly(vinylidene fluoride) (PVDF) based polymer nanocomposites with high‐permittivity nanofillers exhibit outstanding dielectric energy storage performance due to their high dielectric permittivities and breakdown strength. However, their discharge efficiency is relatively low (usually lower than 70%), which limits their practical applications. Here, polymer nanocomposites with a novel interpenetrating gradient structure are designed and demonstrated by cofilling a PVDF matrix with barium zirconate titanate nanofibers and hexagonal boron nitride nanosheets via modified nonequilibrium processing. The interpenetrating gradient structure is highly effective in breaking the trade‐off between discharge energy density and efficiency of the corresponding nanocomposite, as indicated by the concomitantly enhanced discharge energy density (U
e ≈ 23.4 J cm−3) and discharge efficiency (η ≈ 83%). The superior performance is primarily attributed to the rational distribution of nanofillers in the polymer matrix, which raises the height of the potential barrier for charge injection at the dielectric/electrode interface, suppresses electric conduction and contributes to enhanced apparent breakdown strength. Meanwhile, the gradient configuration allows higher volume fraction of high‐permittivity nanofillers without compromising the breakdown strength, leading to higher electric polarization compared with the random configuration. This work provides new opportunities to PVDF‐based polymer nanocomposites with high energy density and discharge efficiency for capacitive energy storage applications.