bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantio‐ and Diastereoselective Synthesis of Chiral Syn‐Aryl β‐Hydroxy α‐Amino Esters via Biocatalytic Dynamic Reductive Kinetic Resolution
Authors: Zhang Qing‐Chun , Lu Zuo‐Lin , Hu Chen , Zhu Kejie , Jiang Meifen , Huang Zedu , Chen Fener 
Published: April 2021

AbstractDevelopment of an efficient, stereoselective, sustainable synthesis of chiral aryl β‐hydroxy α‐amino acids and their derivatives is of paramount importance, owing to the broad utility of these molecules in pharmaceutical application and asymmetric synthesis. We report a systematic study on ketoreductase (KRED)‐catalyzed dynamic reductive kinetic resolution (DYRKR) of aryl α‐amino β‐keto esters 6, furnishing 20 structurally diverse chiral syn‐aryl β‐hydroxy α‐amino esters (syn‐(2S,3R)‐7) in moderate‐to‐excellent isolated yield (up to 93%), along with moderate‐to‐excellent diastereoselectivity (up to >99 : 1 dr) and excellent enantioselectivity (mostly >99% ee). The practical synthesis potential of our developed method was showcased by the asymmetric, chemo‐enzymatic total synthesis of thiamphenicol (1).
Hybrid Amyloid‐Based Redox Hydrogel for Bioelectrocatalytic H2 Oxidation
Authors: Duraffourg Nicolas , Leprince Maxime , Crouzy Serge , Hamelin Olivier , Usson Yves , Signor Luca , Cavazza Christine , Forge Vincent , Albertin Luca 
Published: April 2021

AbstractAn artificial amyloid‐based redox hydrogel was designed for mediating electron transfer between a [NiFeSe] hydrogenase and an electrode. Starting from a mutated prion‐forming domain of fungal protein HET‐s, a hybrid redox protein containing a single benzyl methyl viologen moiety was synthesized. This protein was able to self‐assemble into structurally homogenous nanofibrils. Molecular modeling confirmed that the redox groups are aligned along the fibril axis and are tethered to its core by a long, flexible polypeptide chain that allows close encounters between the fibril‐bound oxidized or reduced redox groups. Redox hydrogel films capable of immobilizing the hydrogenase under mild conditions at the surface of carbon electrodes were obtained by a simple pH jump. In this way, bioelectrodes for the electrocatalytic oxidation of H2 were fabricated that afforded catalytic current densities of up to 270 μA cm−2, with an overpotential of 0.33 V, under quiescent conditions at 45 °C.
Three‐Component Aminoarylation of Electron‐Rich Alkenes by Merging Photoredox with Nickel Catalysis
Authors: Jiang Heng , Yu Xiaoye , Daniliuc Constantin G. , Studer Armido 
Published: April 2021

AbstractA three‐component 1,2‐aminoarylation of vinyl ethers, enamides, ene‐carbamates and vinyl thioethers by synergistic photoredox and nickel catalysis is reported. 2,2,2‐Trifluoroethoxy carbonyl protected α‐amino‐oxy acids are used as amidyl radical precursors. anti‐Markovnikov addition of the amidyl radical to the alkene and Ni‐mediated radical/transition metal cross over lead to the corresponding 1,2‐aminoarylation product. The radical cascade, which can be conducted under practical and mild conditions, features high functional group tolerance and broad substrate scope. Stereoselective 1,2‐aminoarylation is achieved using a L‐(+)‐lactic acid derived vinyl ether as the substrate, offering a novel route for the preparation of protected enantiopure α‐arylated β‐amino alcohols. In addition, 1,2‐aminoacylation of vinyl ethers is achieved by using an acyl succinimide as the electrophile for the Ni‐mediated radical coupling.
Strain‐Engineered Nano‐Ferroelectrics for High‐Efficiency Piezocatalytic Overall Water Splitting
Authors: Su Ran , Wang Zhipeng , Zhu Lina , Pan Ying , Zhang Dawei , Wen Hui , Luo Zheng‐Dong , Li Linglong , Li Fa‐tang , Wu Ming , He Liqiang , Sharma Pankaj , Seidel Jan 
Published: April 2021

AbstractDeveloping nano‐ferroelectric materials with excellent piezoelectric performance for piezocatalysts used in water splitting is highly desired but also challenging, especially with respect to reaching large piezo‐potentials that fully align with required redox levels. Herein, heteroepitaxial strain in BaTiO3 nanoparticles with a designed porous structure is successfully induced by engineering their surface reconstruction to dramatically enhance their piezoelectricity. The strain coherence can be maintained throughout the nanoparticle bulk, resulting in a significant increase of the BaTiO3 tetragonality and thus its piezoelectricity. Benefiting from high piezoelectricity, the as‐synthesized blue‐colored BaTiO3 nanoparticles possess a superb overall water‐splitting activity, with H2 production rates of 159 μmol g−1 h−1, which is almost 130 times higher than that of the pristine BaTiO3 nanoparticles. Thus, this work provides a generic approach for designing highly efficient piezoelectric nanomaterials by strain engineering that can be further extended to various other perovskite oxides, including SrTiO3, thereby enhancing their potential for piezoelectric catalysis.
Cooperative Bond Activation and Facile Intramolecular Aryl Transfer of Nickel–Aluminum Pincer‐type Complexes
Authors: Graziano Brendan J. , Vollmer Matthew V. , Lu Connie C. 
Published: April 2021

AbstractPincer‐type nickel–aluminum complexes were synthesized using two equivalents of the phosphinoamide, [PhNCH2PiPr2]−. The Ni0–AlIII complexes, {(MesPAlP)Ni}2(μ‐N2) and {(MesPAlP)Ni}2(μ‐COD), where MesPAlP is (Mes)Al(NPhCH2PiPr2)2, were structurally characterized. The (PAlP)Ni system exhibited cooperative bond cleavage mediated by the two‐site Ni–Al unit, including oxidative addition of aryl halides, H2 activation, and ortho‐directed C−H bond activation of pyridine N‐oxide. One intriguing reaction is the reversible intramolecular transfer of the mesityl ring from the Al to the Ni site, which is evocative of the transmetalation step during cross‐coupling catalysis. The aryl‐transfer product,(THF)Al(NPhCH2PiPr2)2Ni(Mes), is the first example of a first‐row transition metal–aluminyl pincer complex. The addition of a judicious donor enables the Al metalloligand to convert reversibly between the alane and aluminyl forms via aryl group transfer to and from Ni, respectively. Theoretical calculations support a zwitterionic Niδ−–Alδ+ electronic structure in the nickel–aluminyl complex.
Heterometallic Coinage Metal Acetylenediide Clusters Showing Tailored Thermochromic Luminescence
Authors: Pei Xiao‐Li , Guan Zong‐Jie , Nan Zi‐Ang , Wang Quan‐Ming 
Published: April 2021

AbstractAcetelyenediide (C22−) species have been encapsulated in bimetallic and trimetallic clusters: [(AuL)6Ag7(C≡C)3](BF4)7 (2) and [(AuL)6AgCu6(C≡C)3](BF4)7 (3), L=phenylbis(2‐pyridyl)phosphine (PPhpy2). Single‐crystal X‐ray diffraction analysis revealed that they are isostructural and six silver atoms in 2 are replaced with copper in 3. Both clusters have a trefoil skeleton, which can be viewed as three trigonal bipyramidal (LAu‐C≡C‐AuL)M2Ag (M=Ag/Cu) motifs sharing a common silver atom. TDDFT calculations showed Cu‐doping significantly increases the energy level of (C2‐Cu)‐involved occupied orbital, thus inducing interesting transition coupling of dual‐emission at low temperature. This work not only provides a strategy for constructing heterometallic clusters, but also shows the prospect for pursuing novel thermochromic luminescent materials by incorporating multi‐congeneric metal components.
A Cooperatively Activatable, DNA‐based Fluorescent Reporter for Imaging of Correlated Enzymatic Activities
Authors: Fan Zetan , Zhao Jian , Chai Xin , Li Lele 
Published: April 2021

AbstractThe dynamic variation of the expression profile and spatial landscape of multiple enzymes are crucial factors influencing tumor progression and drug treatment. However, the comprehensive analysis of these events has been hampered by the limitations of existing imaging technologies. Here we report a cooperatively activatable, DNA‐based fluorescent reporter programmed to detect the correlated activity of dual enzymes, telomerase (TE) and apurinic/apyrimidinic endonuclease 1 (APE1), both in vitro and in vivo. The conformational change of the DNA probe can be orthogonally triggered through TE‐induced DNA elongation and APE1‐mediated specific cleavage, producing a fluorescent signal for imaging the activity of the two enzymes in an AND‐gated manner. Furthermore, we demonstrate the capability of the system for specific tumor imaging through “dual lock‐and‐key” strategy, and visualizing the correlated enzymatic activities during drug treatment of cancer.
Antioxidant packaging development and optimization using agroindustrial wastes
Authors: Santos Fabiana Helen , Siqueira Luana Elisa , Cardoso Giselle Pereira , Molina Gustavo , Pelissari Franciele Maria 
Published: April 2021

AbstractThe increasing use of non‐biodegradable materials and the difficulty in recycling most of the available packaging have been pushing the development of biodegradable packaging. In this study, the potential uses of agroindustrial wastes to produce biodegradable films with antioxidant capacity were investigated. Starch films were produced by casting method using bran from jaboticaba peel, mango peel, and broccoli stalk. The influence of the concentration or type of bran in the properties of the films was evaluated through a central composite design. The results were analyzed by response surface and desirability function. Except for elongation and water solubility, the fitted equations were predictive in all studied properties. The films prepared from a higher concentration of mango peel exhibited better antioxidant capacity, while the broccoli stalk had no significant effect on antioxidant properties. The optimal formulation of the film (2.8% of jaboticaba peel and 20.0% of mango peel) and their predicted response variables (0.8 MPa for tensile strength, 40.0 MPa for Young's modulus, 4.5 mg/ml for IC50, and 41.6% for inhibition percentage) were defined according to the results. The optimization was satisfactory and the film presented high antioxidant capacity and moderate mechanical properties, proving to be an alternative to replace plastic packaging.
The aminosilane functionalization of cellulose nanocrystal aerogel via vapor‐phase reaction and its CO2 adsorption characteristics
Authors: Xu Jing , Jia Peipei , Wang Xingjuan , Xie Zhongyuan , Chen Zhangyun , Jiang Hua 
Published: April 2021

AbstractThe cellulose nanocrystal (CNC) aerogel was functionalized using aminosilane via vapor‐phase reaction and then the modified CNC aerogel was characterized by several techniques such as Fourier transform infrared spectroscopy, FE‐SEM, and elemental analysis. Finally, the CO2 adsorption on the aminosilane‐grafted CNC aerogel was featured using a dual‐site Langmuir adsorption model. The result showed triethylamine significantly enhanced the amine loading, being 7.06 mmol g−1 at 120°C. The primary amine groups in the aminosilane survived the vapor‐phase reaction. The amine groups were homogeneously distributed inside the aerogel due to its porous structure. The dual‐site Langmuir model could well describe its CO2 sorption characteristics. The adsorption capacity was up to 2.57 mmolCO2 g−1 at 25°C and 101.33 kPa, of which the chemisorption entirely dominated, and it decreased only 3%–4% after six runs. Therefore, these features positively suggested the vapor‐phase reaction provided a new and feasible method to functionalize CNC aerogel for the capture of CO2.
Seasonal use of a macrotidal estuary by the endangered dwarf sawfish, Pristis clavata
Authors: Morgan David L. , Lear Karissa O. , Dobinson Emma , Gleiss Adrian C. , Fazeldean Travis , Pillans Richard D. , Beatty Stephen J. , Whitty Jeff M. 
Published: April 2021

Abstract

Sawfishes (Family: Pristidae) are one of the most imperilled fish families worldwide. There is an increasingly urgent need to better understand the biology, ecology, and population status of the five sawfish species to develop more effective conservation measures. The dwarf sawfish, Pristis clavata, is one of the least researched members of the pristids, with literature limited to analysing disparate datasets or collations of rare encounters in northern Australia.
This study examined the spatial ecology of dwarf sawfish using targeted surveys and acoustic telemetry to determine its habitat use in a macrotidal estuary in northern Australia. Seventeen dwarf sawfish were tagged with acoustic transmitters and monitored in the Fitzroy River estuary and adjacent King Sound (Kimberley, Western Australia) between August 2015 and November 2017.
Dwarf sawfish observed within the Fitzroy River estuary and King Sound were juveniles, ranging between 740 and 2,540 mm in total length. Catch per unit effort of dwarf sawfish in the late dry season was relatively high in the estuary, with the catch rate in 2015 being one of the highest reported for any sawfish species.
Acoustic detections revealed a distinct seasonal pattern in the use of different parts of the estuary and King Sound, which was found to be driven by salinity. Dwarf sawfish predominately occupied a single large pool near the terminus of the tidal limit in the late dry season (August–November), before transitioning to regions in closer proximity to the river mouth or in King Sound in the wet and early dry seasons (December–July).
Given the high abundance and residency of dwarf sawfish in the Fitzroy River estuary, this area is an important nursery for the species during the late dry season and should be formally recognized as a habitat protection area for the species.
Needs assessment in unmet healthcare and family support services: A survey of caregivers of children and youth with autism spectrum disorder in Delaware
Authors: Srinivasan Sudha , Ekbladh Annalisa , Freedman Brian , Bhat Anjana 
Published: April 2021

AbstractThe study aimed to collect data from families of children and youth with Autism Spectrum Disorder (ASD) in the state of Delaware, USA to understand their ongoing needs and challenges in accessing child healthcare and family support services. We analyzed responses from 263 caregivers of children and youth with ASD from 3 to 24 years using a statewide needs assessment survey. Over 50% caregivers indicated having unmet needs relative to both child/youth healthcare services and family support services. Between 24 and 38% caregivers expressed unmet needs for healthcare services such as social skills training, speech‐language therapy, behavioral intervention, and occupational therapy for their child and 20–24% expressed needs for family support services such as respite care, parent/sibling support groups, counseling, and babysitting support. Additionally, number of prior early interventions received, limitations in accessing healthcare services, and unmet needs for family support services significantly predicted child/youth unmet healthcare needs. Greater ASD severity and difficulties accessing child/youth healthcare services predicted participant's functional dependence on caregivers for activities of daily living. Together, these findings call for designing holistic, family‐centered interventions that address needs of both children and youth with ASD and their families.Lay summaryA statewide needs assessment survey of caregivers of children and youth with ASD revealed that 50% responders had unmet needs relative to both child/youth healthcare services and family support services. Number of prior services received, limitations in accessing healthcare, and unmet needs for family support are linked to child/youth unmet healthcare needs. Severity of autism and difficulties accessing child/youth healthcare are associated with participant's functional dependence. Together, these findings call for placing the family at the heart of the service system in ASD.
Implications of Co‐Feeding Water on the Growth Mechanisms of Retained Species on a SAPO‐18 Catalyst during the Methanol‐to‐Olefins Reaction
Authors: Valecillos José , Hita Idoia , Sastre Enrique , Aguayo Andrés T. , Castaño Pedro 
Published: April 2021

AbstractThe dynamics of retained and deactivating species in a SAPO‐18 catalyst during the methanol‐to‐olefins reaction have been followed using a combination of ex‐situ and in‐situ techniques in differential and integral reactors.The retained species were analyzed using extraction, in‐situ FTIR and in‐situ UV‐vis spectroscopies combined with online product analysis (gas chromatography and mass spectrometry). The composition of the extracted soluble species was determined using gas chromatography‐mass spectrometry and that of the insoluble species using high‐resolution mass spectrometry. We observe a decrease in the formation and degradation rates of retained species when co‐feeding water, whereas the extent of the decreases is the same across the entire spectrum of retained molecules. This indicates that co‐feeding water unselectively quenches the formation of active and deactivating species. At the same time, the catalyst has an extended lifetime when co‐feeding water due to the diffusion of species (particularly olefins) out of the SAPO‐18 crystals, and subsequent growth of heavy polycyclic aromatic structures that imply less deactivation. These conclusions can be extrapolated to other MTO catalysts with relatively similar pore topology such as SAPO‐34 or SSZ‐13 structures.
Li[(FSO2)(n‐C4F9SO2)N]: A Difunctional Salt for Ethylene‐Carbonate‐ and Additive‐Free Electrolyte for Li‐Ion Cells
Authors: Ma Qiang , Song Ziyu , Liu Juanjuan , Zheng Liping , Zhang Heng , Huang Xuejie , Armand Michel , Feng Wenfang , Nie Jin , Zhou Zhibin 
Published: April 2021

AbstractAn ethylene carbonate (EC) free and additive‐free base electrolyte, simply comprising a solid‐electrolyte‐interphase (SEI)‐forming salt (i. e., lithium (fluorosulfonyl)(n‐nonafluorobutanesulfonyl)imide (Li[(FSO2)(n‐C4F9SO2)N], LiFNFSI)) and dimethyl carbonate (DMC), for stable cycling graphite||LiNi0.6Mn0.2Co0.2O2 (NMC622) full cells at different temperatures (i. e., 25 °C and 60 °C) is reported. The utilization of the LiFNFSI‐based, EC‐free electrolyte endows the graphite||NMC622 cell with superior cycling performances, especially at an elevated temperature of 60 °C, outperforming the lithium hexafluorophosphate (LiPF6)‐based ones with and without EC. X‐ray photoelectron spectroscopy and electrochemical impedance spectra analyses demonstrate that a thin, compact, and robust Li‐ion conductive SEI film is formed on the overall surface of the graphite anode in LiFNFSI‐DMC, while that formed in LiPF6‐DMC is discrete. These results suggest the potential application of LiFNFSI as a main conducting salt for building high‐performance LIBs with EC‐free electrolytes.
Nucleophilic Reactions of Osmanaphthalynes with PMe3 and H2O
Authors: Zhang Ming‐Xing , Lin Lu , Yang Xiaofei , Yin Jun , Zhu Jun , Liu Sheng Hua 
Published: April 2021

AbstractMembers of a new class of complexes, 2(CF3), 2(H), 2(Br), 2(I), and 2(OCH3), have been synthesized in a one‐pot method involving the treatment of osmanaphthalynes bearing corresponding substituents (1(CF3), 1(H), 1(Br), 1(I), and 1(OCH3)) with trimethylphosphine (PMe3) and water. The main reaction process involves two steps, namely a ligand‐exchange with trimethylphosphine and nucleophilic addition of water to the Os≡C bond of the osmanaphthalyne. The substituents have a significant influence on the rate of the reaction, as befits a nucleophilic addition. Fortunately, the key intermediate [1(OCH3)]′ could be successfully captured, and the detailed reaction mechanism has been explored with the aid of density functional theory (DFT) calculations, which were in excellent agreement with the experimental findings. All of the target complexes have been fully characterized by 1H, 31P{1H}, and 13C{1H} NMR spectroscopy, high‐resolution mass spectrometry, and elemental analysis.
Forever Young: Structural Stability of Telomeric Guanine Quadruplexes in the Presence of Oxidative DNA Lesions**
Authors: Miclot Tom , Corbier Camille , Terenzi Alessio , Hognon Cécilia , Grandemange Stéphanie , Barone Giampaolo , Monari Antonio 
Published: April 2021

AbstractHuman telomeric DNA, in G‐quadruplex (G4) conformation, is characterized by a remarkable structural stability that confers it the capacity to resist to oxidative stress producing one or even clustered 8‐oxoguanine (8oxoG) lesions. We present a combined experimental/computational investigation, by using circular dichroism in aqueous solutions, cellular immunofluorescence assays and molecular dynamics simulations, that identifies the crucial role of the stability of G4s to oxidative lesions, related also to their biological role as inhibitors of telomerase, an enzyme overexpressed in most cancers associated to oxidative stress.
Single Mn Atom Anchored on Nitrogen‐Doped Graphene as a Highly Efficient Electrocatalyst for Oxygen Reduction Reaction
Authors: Li Lei , Li Yameng , Huang Rao , Cao Xinrui , Wen Yuhua 
Published: April 2021

AbstractSingle Mn atom on nitrogen‐doped graphene (MnN4‐G) has exhibited good structural stability and high activity for the adsorption and dissociation of an O2 molecule, becoming a promising single‐atom catalyst (SAC) candidate for oxygen reduction reaction (ORR). However, the catalytic activity of MnN4‐G for the ORR and the optimal reaction pathway remain obscure. In this work, density‐functional theory calculations were employed to comprehensively investigate all the possible pathways and intermediate reactions of the ORR on MnN4‐G. The feasible active sites and the most stable adsorption configurations of the intermediates and transition states during the ORR were identified. Screened from all the possibilities, three optimal four‐electron O2 hydrogenation pathways with an ultralow energy barrier of 0.13 eV were discovered that are energetically more favorable than direct O2 dissociation pathways. Analysis of the free energy diagram further verified the thermodynamical feasibility of the three pathways. Thus, MnN4‐G possesses superior ORR activity. This study provides a fundamental understanding of the design of highly efficient SACs for the ORR.
Rapidly Adaptive All‐covalent Nanoparticle Surface Engineering
Authors: Diez‐Castellnou Marta , Suo Rongtian , Marro Nicolas , Matthew Saphia A. L. , Kay Euan R. 
Published: April 2021

AbstractEmerging nanotechnologies demand the manipulation of nanoscale components with the same predictability and programmability as is taken for granted in molecular synthetic methodologies. Yet installing appropriately reactive chemical functionality on nanomaterial surfaces has previously entailed compromises in terms of reactivity scope, functionalization density, or both. Here, we introduce an idealized dynamic covalent nanoparticle building block for divergent and adaptive post‐synthesis modification of colloidal nanomaterials. Acetal‐protected monolayer‐stabilized gold nanoparticles are prepared via operationally simple protocols and are stable to long‐term storage. Tunable surface densities of reactive aldehyde functionalities are revealed on‐demand, leading to a wide range of adaptive surface engineering options from one nanoscale synthon. Analytically tractable with molecular precision, interfacial reaction kinetics and dynamic surface constitutions can be probed in situ at the ensemble level. High functionalization densities combined with rapid equilibration kinetics enable environmentally adaptive surface constitutions and rapid nanoparticle property switching in response to simple chemical effectors.