bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mortality Due to COVID-19 in the Elderly: Integrative Literature Review
Authors: Carvalho Dayara de Nazaré Rosa de , Aguiar Viviane Ferraz Ferreira de , Bendelaque Dandara de Fátima Ribeiro , Neves Lorena Nayara Alves , Sobrinho Celice Ruanda Oliveira , Martins Jaqueline Dantas Neres , Costa Rafael Everton Assunção Ribeiro da , Souza Susi dos Santos Barreto de , Pamplona Mônica Custódia do Couto Abreu , Nascimento Marcia Helena Machado , Sá Antônia Margareth Moita , Feitosa Elisa da Silva , Peixoto Ivonete Vieira Pereira 
Published: July 2020

Aims: Explore national and international literature about mortality in elderly caused by COVID-19.
Methodology: An integrative literature review was performed using the databases: Virtual Health Library (VHL), PubMed/Medline (National Library of Medicine and National Institutes of Health/Medical Literature Analyzes Sand Retrieval System Online) and Cochrane Library. The selection of articles occurred from the combination of the descriptors: “Coronavirus Infections”; “Aged” and “Mortality” mediated by the Boolean operator “AND”. After evaluating and synthesizing the articles, the data were analyzed using the IRaMuTeQ software, a program that is anchored in the R software.
Results: After analyzing the identification of textual domains and interpretation, 4 classes emerged: 1) The importance of tests for the control and good prognosis of infection in the elderly; 2) Predictors related to high mortality in the elderly; 3) Comorbidities associated with a high mortality rate; 4) The reasons for the transmission of the virus are more worrying in the elderly.
Conclusion: The elderly population presents different risks for mortality, an example of physiological changes such as immune senescence, critical, social and psychological factors and the presence of comorbidities.
Recoverable Photolithographic Patterning for Polarized Display and Encryption
Authors: Xu Lirong , Feng Yechang , Yu Dingshan , Zheng Zhikun , Chen Xudong , Hong Wei 
Published: July 2020

AbstractAnisotropic plasmonic nanostructures have attracted significant attention in recent years because of their unique optical properties and potential applications in holograms, thermotherapy, and information encoding. Herein, a gold nanorods/photoactive hydrogel system with excellent mechanical and photoreactive recoverability is developed. Multiscale engineering exploits the synergy among components to endow the system with rapid self‐healing ability, repetitive photolithographic capability, robust mechanical properties, and 3D printability, enabling multiple encoding routes including polarized patterns based on depolarization under UV‐lithography, polarized patterns by direct ink writing, invisible patterns through increased light absorption by depolarization, and thermal imaging patterns by anisotropic photothermal effects. This approach provides a facile and sustainable method for polarized patterning, thereby contributing to smart devices for applications in display, information encryption, and anti‐counterfeiting.
Heat Diffusion‐Induced Gradient Energy Level in Multishell Bisulfides for Highly Efficient Photocatalytic Hydrogen Production
Authors: Wang Bilin , Guo Shaohui , Xin Xu , Zhang Youzi , Wang Yijin , Li Chenghua , Song Yaru , Deng Dongshan , Li Xuanhua , Sobrido Ana Jorge , Titirici Maria‐Magdalena 
Published: July 2020

AbstractInsufficient light absorption and low carrier separation/transfer efficiency constitute two key issues that hinder the development of efficient photocatalytic hydrogen production. Here, multishell ZnS/CoS2bisulfide microspheres with gradient distribution of Zn based on the heat diffusion theory are designed. The Zn distribution can be adjusted by regulating the heating rate and manipulating the diffusion coefficients of the different elements conforming the multishell photocatalyst. Because of the unique structure, a gradient energy level is created from the core to the exterior of the multishell microspheres, which effectively facilitates the exciton separation and electron transfer. In addition, stronger light absorption and larger specific surface area have been achieved in the multishell ZnS/CoS2photocatalysts. As a result, the multishell ZnS/CoS2microspheres with gradient distribution of Zn exhibit a remarkable hydrogen production rate of 8001µmol g−1h−1, which is 3.5 times higher than that of the normal multishell ZnS/CoS2particles with well‐distributed Zn and 11.3 times higher than that of the mixed nonshell ZnS and CoS2particles. This work demonstrates for the first time that controlling the diffusion rate of the different elements in the semiconductor is an effective route to simultaneously regulate morphology and structure to design highly efficient photocatalysts.
Generation of Competitive and Coexisting Two Pairs of Biphotons in Single Hot Atomic Vapor Cell
Authors: Li Kangkang , Feng Yuan , Li Xinghua , Gu Bingling , Cai Yin , Zhang Yanpeng 
Published: July 2020

AbstractThe non‐classical states of light serve as a potential candidate for emerging quantum information process. A processing trend to enhance its scalability is to integrate multiple nonlinear processes with the dressed‐state picture into a single device, and therefore, are useful for quantum computations. Here, a novel method is proposed to experimentally achieve the generation of coexisting two pairs of narrow‐band biphotons by two four‐wave mixing processes in a single hot rubidium vapor cell. Based on the photon‐atom nonlinear interfaces, the generated biphotons exhibits genuine entanglement in time–energy. Meanwhile, the nonlinear susceptibility with the dressed‐state picture decides the temporal correlation of the biphotons wave packet as a damped periodic Rabi oscillation, suggesting the property of the high‐dimensional time–energy entangled state. Such a high‐dimensional entangled state also is an efficient way to enhance information carrying capacity. By alternating two nonlinear susceptibilities in a single device, respectively, there exists a competition of the generation rate between such two pairs of biphotons. Moreover, both generated two pairs of biphotons that violate the Cauchy–Schwarz inequality and show their non‐classical behavior.
Activatable CRISPR Transcriptional Circuits Generate Functional RNA for mRNA Sensing and Silencing
Authors: Ying Zhan‐Ming , Wang Fenglin , Chu Xia , Yu Ru‐Qin , Jiang Jian‐Hui 
Published: July 2020

AbstractCRISPR‐dCas9 systems that are precisely activated by cell‐specific information facilitate the development of smart sensors or therapeutic strategies. We report the development of an activatable dCas9 transcriptional circuit that enables sensing and silencing of mRNA in living cells using hybridization‐mediated structure switching for gRNA activation. The gRNA is designed with the spacer sequence blocked by a hairpin structure, and mRNA hybridization induces gRNA structure switching and activates the transcription of reporter RNA. An mRNA sensor developed using a light‐up RNA reporter shows high sensitivity and fast‐response imaging of survivin mRNA in cells under drug treatments and different cell lines. Furthermore, a feedback circuit is engineered by incorporating a small hairpin RNA in the reporter RNA, demonstrating a smart strategy for dynamic sensing and silencing of survivin with induced tumor cell apoptosis. This circuit illustrates a broadly applicable platform for the development of cell‐specific sensing and therapeutic strategies.
Correlating Glycoforms of DC‐SIGN with Stability Using a Combination of Enzymatic Digestion and Ion Mobility Mass Spectrometry
Authors: Yen Hsin‐Yung , Liko Idlir , Gault Joseph , Wu Di , Struwe Weston B. , Robinson Carol V. 
Published: July 2020

AbstractThe immune scavenger protein DC‐SIGN interacts with glycosylated proteins and has a putative role in facilitating viral infection. How these recognition events take place with different viruses is not clear and the effects of glycosylation on the folding and stability of DC‐SIGN have not been reported. Herein, we report the development and application of a mass‐spectrometry‐based approach to both uncover and characterise the effects of O‐glycans on the stability of DC‐SIGN. We first quantify the Core 1 and 2 O‐glycan structures on the carbohydrate recognition and extracellular domains of the protein using sequential exoglycosidase sequencing. Using ion mobility mass spectrometry, we show how specific O‐glycans, and/or single monosaccharide substitutions, alter both the overall collision cross section and the gas‐phase stability of the DC‐SIGN isoforms. We find that rather than the mass or length of glycoprotein modifications, the stability of DC‐SIGN is better correlated with the number of glycosylation sites.
A Boosted Critical Temperature of 166 K in Superconducting D3S Synthesized from Elemental Sulfur and Hydrogen
Authors: Minkov Vasily S. , Prakapenka Vitali B. , Greenberg Eran , Eremets Mikhail I. 
Published: July 2020

AbstractThe discovery of superconductivity in H3S at 203 K marked an advance towards room‐temperature superconductivity and demonstrated the potential of H‐dominated compounds to possess a high critical temperature (Tc). There have been numerous reports of the H‐S system over the last five years, but important questions remain unanswered. It is crucial to verify whether the Tc was determined correctly for samples prepared from compressed H2S, since they are inevitably contaminated with H‐depleted byproducts. Here, we prepare stoichiometric H3S by direct in situ synthesis from elemental S and excess H2. The Im
m phase of D3S samples exhibits a Tc significantly higher than previously reported values (ca. 150 K), reaching a maximum Tc of 166 K at 157 GPa. Furthermore, we confirm that the sharp decrease in Tc below 150 GPa is accompanied by continuous rhombohedral structural distortions and demonstrate that the Cccm phase is non‐metallic, with molecular H2 units in the crystal structure.
Enantio‐ and Site‐Selective α‐Fluorination of N‐Acyl 3,5‐Dimethylpyrazoles Catalyzed by Chiral π–CuII Complexes
Authors: Ishihara Kazuaki , Nishimura Kazuki , Yamakawa Katsuya 
Published: July 2020

AbstractCatalytic enantioselective α‐fluorination reactions of carbonyl compounds are among the most powerful and efficient synthetic methods for constructing optically active α‐fluorinated carbonyl compounds. Nevertheless, α‐fluorination of α‐nonbranched carboxylic acid derivatives is still a big challenge because of relatively high pKa values of their α‐hydrogen atoms and difficulty of subsequent synthetic transformation without epimerization. Herein we show that chiral copper(II) complexes of 3‐(2‐naphthyl)‐l‐alanine‐derived amides are highly effective catalysts for the enantio‐ and site‐selective α‐fluorination of N‐(α‐arylacetyl) and N‐(α‐alkylacetyl) 3,5‐dimethylpyrazoles. The substrate scope of the transformation is very broad (25 examples including a quaternary α‐fluorinated α‐amino acid derivative). α‐Fluorinated products were converted into the corresponding esters, secondary amides, tertiary amides, ketones, and alcohols with almost no epimerization in high yield.
Atropisomerism in Diarylamines: Structural Requirements and Mechanisms of Conformational Interconversion
Authors: Costil Romain , Sterling Alistair J. , Duarte Fernanda , Clayden Jonathan 
Published: July 2020

AbstractIn common with other hindered structures containing two aromatic rings linked by a short tether, diarylamines may exhibit atropisomerism (chirality due to restricted rotation). Previous examples have principally been tertiary amines, especially those with cyclic scaffolds. Little is known of the structural requirement for atropisomerism in structurally simpler secondary and acyclic diarylamines. In this paper we describe a systematic study of a series of acyclic secondary diarylamines, and we quantify the degree of steric hindrance in the ortho positions that is required for atropisomerism to result. Through a detailed experimental and computational analysis, the role of each ortho‐substituent on the mechanism and rate of conformational interconversion is rationalised. We also present a simple predictive model for the design of configurationally stable secondary diarylamines.
Engineered Anisotropic Fluids of Rare‐Earth Nanomaterials
Authors: Shao Baiqi , Wan Sikang , Yang Chenjing , Shen Jianlei , Li Yiwen , You Hongpeng , Chen Dong , Fan Chunhai , Liu Kai , Zhang Hongjie 
Published: July 2020

AbstractThe self‐assembly of inorganic nanoparticles into well‐ordered structures in the absence of solvents is generally hindered by van der Waals forces, leading to random aggregates between them. To address the problem, we functionalized rigid rare‐earth (RE) nanoparticles with a layer of flexible polymers by electrostatic complexation. Consequently, an ordered and solvent‐free liquid crystal (LC) state of RE nanoparticles was realized. The RE nanomaterials including nanospheres, nanorods, nanodiscs, microprisms, and nanowires all show a typical nematic LC phase with one‐dimensional orientational order, while their microstructures strongly depend on the particles’ shape and size. Interestingly, the solvent‐free thermotropic LCs possess an extremely wide temperature range from −40 °C to 200 °C. The intrinsic ordering and fluidity endow anisotropic luminescence properties in the system of shearing‐aligned RE LCs, offering potential applications in anisotropic optical micro‐devices.
Stable Ti3+ Defects in Oriented Mesoporous Titania Frameworks for Efficient Photocatalysis
Authors: Lan Kun , Wang Ruicong , Wei Qiulong , Wang Yanxiang , Hong Anh , Feng Pingyun , Zhao Dongyuan 
Published: July 2020

AbstractBy introducing a compatible reducing agent (2‐ethylimidazole) into a mono‐micelle assembly process, we present a type of ordered mesoporous TiO2 microspheres that combines radially aligned mesostructure with Ti3+ defects in mesoporous frameworks. Such reductant acts as a building block of mesostructured frameworks and reduces Ti4+ in situ to generate defects during calcination, giving rise to the coexistence of bulk Ti3+ defects and an ordered mesostructure. The mesoporous TiO2 has both excellent mesoporosity (a high surface area of 106 m2 g−1, a mean pore size of 18.4 nm) and stable defects with an extended photoresponse. Such integration of unique mesoscopic architecture and atomic vacancies provide both effective mass transportation and enhanced light utilization, leading to a remarkable increase in H2 generation rate. A maximum H2 evolution rate of 19.8 mmol g−1 h−1 can be achieved, along with outstanding stability under solar light.
Protonenvermittelter Ringschluss eines negativ photochromen, Azulen‐basierten Diarylethens
Authors: Hou Ian Cheng‐Yi , Berger Fabian , Narita Akimitsu , Müllen Klaus , Hecht Stefan 
Published: July 2020

AbstractAuf Protonen ansprechende photochrome Moleküle sind aufgrund ihrer Fähigkeit, auf nicht‐invasive schnelle optische Stimuli zu reagieren, und wegen der ubiquitären Bedeutung von Protonierungs‐ und Deprotonierungsprozessen, sehr interessant. Üblicherweise befinden sich die sauren/basischen Stellen dieser Moleküle an Heteroatomen, die orthogonal zum photoaktiven π‐Zentrum ausgerichtet sind. In dieser Arbeit wird Azulen, ein protonensensitiver reiner Kohlenwasserstoff, in das Gerüst eines Diarylethen‐Photoschalters eingebaut. Dieser zeigt einen bisher ungekannten, protonenvermittelten, negativ photochromen Ringschluss. Veränderungen seiner optischen Eigenschaften durch Protonierung, sowohl in der offenen, als auch in der geschlossenen Form, sind viel ausgeprägter als die von Diarylethen‐Photoschaltern mit Säure/Base‐Gruppen auf Heteroatombasis. Das einzigartige Verhalten des neuen Photoschalters kann auf die direkte Protonierung seines π‐Systems zurückgeführt werden, was sowohl durch 1H‐NMR als auch durch theoretische Berechnungen belegt wird. Unsere Ergebnisse zeigen das große Potenzial der Einbindung nicht‐alternierender Kohlenwasserstoffe in photochrome Systeme für die Entwicklung von molekularen Schaltern, die auf unterschiedliche Stimuli reagieren.
Polyoxometalate‐Based Compounds for Photo‐ and Electrocatalytic Applications
Authors: Li Ning , Liu Jiang , Dong Bao‐Xia , Lan Ya‐Qian 
Published: July 2020

AbstractPhoto/electrocatalysis of water (H2O) splitting and CO2 reduction reactions is a promising strategy to alleviate the energy crisis and excessive CO2 emissions. For the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and CO2 reduction reaction (CO2RR) involved, the development of effective photo/electrocatalysts is critical to reduce the activation energy and accelerate the sluggish dynamics. Polyoxometalate (POM)‐based compounds with tunable compositions and diverse structures are emerging as unique photo/electrocatalysts for these reactions as they offer unparalleled advantages such as outstanding solution and redox stability, quasi‐semiconductor behaviour, etc. This Minireview provides a basic introduction related to photo/electrocatalytic HER, OER and CO2RR, followed by the classification of pristine POM‐based compounds toward different catalytic reactions. Recent breakthroughs in engineering POM‐based compounds as efficient photo/electrocatalysts are highlighted. Finally, the advantages, challenges, strategies and outlooks of POM‐based compounds on improving photo/electrocatalytic performance are discussed.
Detailed Visualization of Aromaticity Using Isotropic Magnetic Shielding
Authors: Lampkin Bryan J. , Karadakov Peter B. , VanVeller Brett 
Published: July 2020

AbstractFor many years, Clar's aromatic sextet theory has served as a qualitative method for assessing the aromatic character of polycyclic aromatic hydrocarbons. A new approach, based on the calculation of isotropic magnetic shielding (IMS) contour plots, is shown to provide a feature‐rich picture of aromaticity that is both quantitative yet still easily interpreted. Chemists are visual creatures who are adept at discerning reactivity and chemical behavior from molecular structures. To quote Roald Hoffmann, “People like pictures. Chemists live off them.” Thus, the detailed image analysis we present simultaneously provides quantitative assessment of electronic structure, which is still easy‐to‐understand through visual inspection, embedded in an aesthetically appealing and intuitive picture that draws the reader in. We provide novel computed IMS contour plots for a representative selection of aromatic molecules. Where Clar's static drawings capture only a partial sketch of the electronic properties of a molecule, IMS contour plots present a detailed, global landscape of a molecule that sums all possible resonance structures. This novel analysis allows us to correct certain drawbacks of Clar's analysis with respect to polycyclic aromatics and quantitatively assess the bonding and electronic structure of acene hydrocarbons.
Synthesis of Robust MOFs@COFs Porous Hybrid Materials via an Aza‐Diels–Alder Reaction: Towards High‐Performance Supercapacitor Materials
Authors: Peng Haijun , Raya Jésus , Richard Fanny , Baaziz Walid , Ersen Ovidiu , Ciesielski Artur , Samorì Paolo 
Published: July 2020

AbstractMetal–organic frameworks (MOFs) and covalent organic frameworks (COFs) have attracted enormous attention in recent years. Recently, MOF@COF are emerging as hybrid architectures combining the unique features of the individual components to enable the generation of materials displaying novel physicochemical properties. Herein we report an unprecedented use of aza‐Diels–Alder cycloaddition reaction as post‐synthetic modification of MOF@COF‐LZU1, to generate aza‐MOFs@COFs hybrid porous materials with extended π‐delocalization. A a proof‐of‐concept, the obtained aza‐MOFs@COFs is used as electrode in supercapacitors displaying specific capacitance of 20.35 μF cm−2 and high volumetric energy density of 1.16 F cm−3. Our approach of post‐synthetic modification of MOFs@COFs hybrids implement rational design for the synthesis of functional porous materials and expands the plethora of promising application of MOFs@COFs hybrid porous materials in energy storage applications.
124I Radiolabeling of a AuIII‐NHC Complex for In Vivo Biodistribution Studies
Authors: Guarra Federica , Terenzi Alessio , Pirker Christine , Passannante Rossana , Baier Dina , Zangrando Ennio , Gómez‐Vallejo Vanessa , Biver Tarita , Gabbiani Chiara , Berger Walter , Llop Jordi , Salassa Luca 
Published: July 2020

AbstractAuIII complexes with N‐heterocyclic carbene (NHC) ligands have shown remarkable potential as anticancer agents, yet their fate in vivo has not been thoroughly examined and understood. Reported herein is the synthesis of new AuIII‐NHC complexes by direct oxidation with radioactive [124I]I2 as a valuable strategy to monitor the in vivo biodistribution of this class of compounds using positron emission tomography (PET). While in vitro analyses provide direct evidence for the importance of AuIII‐to‐AuI reduction to achieve full anticancer activity, in vivo studies reveal that a fraction of the AuIII‐NHC prodrug is not immediately reduced after administration but able to reach the major organs before metabolic activation.
Sandwiched meshes with superwettability for oil/water separation and heavy metal ion absorption
Authors: Dong Wei , Yang Ling , Qian Fuping , Lv Zhong , Wu Chunhua , Xiang Tengfei , Chen Depeng 
Published: July 2020

AbstractOil/water separation and heavy metal ion adsorptions have become a worldwide challenge due to the global industrial development and its indiscriminate discharge. Large numbers of methods have been developed to solve the problems, among which using superwettability material to selective separation is one of an efficient approach. However, this method cannot adsorb the heavy metal ions from water. Herein, we developed superwettability meshes that can not only separate oil/water after modification but also adsorb heavy metal ions before modification, which is just sandwiching an adsorbent layer between the meshes. The results showed that this method can separate most of oil/water mixtures with high efficiency (higher than 95%) as well as favorable recyclability. Besides, it can separate oil/water emulsion easily. In addition, the carbon layer between the meshes can adsorb heavy metal ions such as Ni(II), Cr(VI) (in the form of Cr2O72−), and Cd(II) with high adsorption efficiency. More importantly, the carbon layer can be replaced by any other powers such as metal–organic frameworks (MOFs) and magnetic particle to extend the applications. We believe that such a novel and simple approach can provide some new perspectives to settle the environmental problems.
The role of structural evolution of polyacrylonitrile fibers during thermal oxidative stabilization on mechanical properties
Authors: Ge Yuan , Fu Zhongyu , Zhang Mingyao , Zhang Huixuan 
Published: July 2020

AbstractThe effects of chemical and physical structural evolution of polyacrylonitrile (PAN)‐based carbon fibers precursor during thermal oxidative stabilization (TOS) on the mechanical properties of stabilized fibers were systematically studied. The results of Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction, and density gradient column showed that the PAN fibers treated with high temperature and for long time have higher extent of cyclization, oxygen content, and crosslinking content. The crystallinity and crystallite size decreased with the increase of TOS time and temperature, whereas the bulk density of the stabilized fibers increased. The mechanical property results indicated that the decrease in tensile strength was inseparable from the formation of the cyclic structure and the amorphization transition of the crystal structure. The fibers have better structural stability when the extent of cyclization was 80–83%, the crystallinity was 34–45%, and the bulk density of stabilized fibers was 1.33–1.35 g/cm3, but exceeding these ranges, a serious skin‐core structure appeared.