bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorus Analogues of Methyl Nitrite and Nitromethane: CH3OPO and CH3PO2
Authors: Zhao Xiaofang , Chu Xianxu , Rauhut Guntram , Chen Changyun , Song Chao , Lu Bo , Zeng Xiaoqing 
Published: June 2019

AbstractMethoxyphosphinidene oxide (CH3OPO) and isomeric methyldioxophosphorane (CH3PO2) are key intermediates in the degradation of organophosphorus compounds (OPCs). Unlike the nitrogen analogues CH3ONO and CH3NO2, the experimental data for these two prototypical OPCs are scarce. By high‐vacuum flash pyrolysis (HVFP) of the diazide CH3OP(O)(N3)2 at 1000 K, the cis and trans conformers of CH3OPO have been generated in the gas phase and subsequently isolated in cryogenic Ar and N2 matrices for IR spectroscopic characterization. Upon 266 nm laser irradiation of CH3OPO, cis→trans conformational conversion occurs with concurrent isomerization to CH3PO2. The spectroscopic identification of CH3OPO and CH3PO2 is supported by D‐, 13C‐, and 18O‐isotope labeling and quantum chemical calculations at the CCSD(T)‐F12a/cc‐pVTZ‐F12 level using configuration‐selective vibrational configuration interaction (VCI).
Hydrogen Bond Directed ortho‐Selective C−H Borylation of Secondary Aromatic Amides
Authors: Bai Shao‐Tao , Bheeter Charles B. , Reek Joost N. H. 
Published: June 2019

AbstractReported is an iridium catalyst for ortho‐selective C−H borylation of challenging secondary aromatic amide substrates, and the regioselectivity is controlled by hydrogen‐bond interactions. The BAIPy‐Ir catalyst forms three hydrogen bonds with the substrate during the crucial activation step, and allows ortho‐C−H borylation with high selectivity. The catalyst displays unprecedented ortho selectivities for a wide variety of substrates that differ in electronic and steric properties, and the catalyst tolerates various functional groups. The regioselective C−H borylation catalyst is readily accessible and converts substrates on gram scale with high selectivity and conversion.
Metal‐Free Oxidative B−N Coupling of nido‐Carborane with N‐Heterocycles
Authors: Yang Zhongming , Zhao Weijia , Liu Wei , Wei Xing , Chen Meng , Zhang Xiao , Zhang Xiaolei , Liang Yong , Lu Changsheng , Yan Hong 
Published: June 2019

AbstractA general method for the oxidative substitution of nido‐carborane (7,8‐C2B9H12−) with N‐heterocycles has been developed by using 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) as an oxidant. This metal‐free B−N coupling strategy, in both inter‐ and intramolecular fashions, gave rise to a wide array of charge‐compensated, boron‐substituted nido‐carboranes in high yields (up to 97 %) with excellent functional‐group tolerance under mild reaction conditions. The reaction mechanism was investigated by density‐functional theory (DFT) calculations. A successive single‐electron transfer (SET), B−H hydrogen‐atom transfer (HAT), and nucleophilic attack pathway is proposed. This method provides a new approach to nitrogen‐containing carboranes with potential applications in medicine and materials.
Asymmetric Catalytic Formal 1,4‐Allylation of β,γ‐Unsaturated α‐Ketoesters: Allylboration/Oxy‐Cope Rearrangement
Authors: Tang Qiong , Fu Kai , Ruan Peiran , Dong Shunxi , Su Zhishan , Liu Xiaohua , Feng Xiaoming 
Published: June 2019

AbstractA highly enantioselective formal conjugate allyl addition of allylboronic acids to β,γ‐unsaturated α‐ketoesters has been realized by employing a chiral NiII/N,N′‐dioxide complex as the catalyst. This transformation proceeds by an allylboration/oxy‐Cope rearrangement sequence, providing a facile and rapid route to γ‐allyl‐α‐ketoesters with moderate to good yields (65–92 %) and excellent ee values (90–99 % ee). The isolation of 1,2‐allylboration products provided insight into the mechanism of the subsequent oxy‐Cope rearrangement reaction: substrate‐induced chiral transfer and a chiral Lewis acid accelerated process. Based on the experimental investigations and DFT calculations, a rare boatlike transition‐state model is proposed as the origin of high chirality transfer during the oxy‐Cope rearrangement.
Fibrocytes in Chronic Periaortitis: A Novel Mechanism Linking Inflammation and Fibrosis
Authors: Nicastro Maria , Vescovini Rosanna , Maritati Federica , Palmisano Alessandra , Urban Maria L. , Incerti Monia , Fenaroli Paride , Peyronel Francesco , Benigno Giuseppe D. , Mangieri Domenica , Volpi Riccardo , Becchi Gabriella , Romagnani Paola , Corradi Domenico , Vaglio Augusto 
Published: June 2019

ObjectiveChronic periaortitis (CP) is a rare disease characterized by periaortic and periiliac fibroinflammatory tissue. The pathogenic mechanisms leading to tissue accumulation and activation of fibroblasts are unclear. This study was undertaken to explore the role of fibrocytes, circulating precursors of tissue fibroblasts, in patients with CP.MethodsWe studied 44 patients with newly diagnosed CP and 30 healthy controls. Circulating fibrocytes were identified as Col1+CD45+ cells using flow cytometry. Retroperitoneal tissue biopsy samples from 9 CP patients were stained with anti–type I procollagen, anti‐CXCR4, and anti‐CD45 antibodies and analyzed by confocal microscopy to detect tissue‐infiltrating fibrocytes. Circulating levels and tissue expression of CXCL12, a CXCR4 ligand that promotes fibrocyte homing, were investigated using enzyme‐linked immunosorbent assay and immunohistochemistry, respectively. We also characterized T helper polarization in biopsy samples from CP patients and measured serum levels of a panel of cytokines that are hallmarks of T helper responses and capable of influencing fibrocyte differentiation.ResultsThe frequency of circulating Col1+CD45+ fibrocytes was higher in patients than in controls (P = 0.0371). CD45+proCol1+ and CXCR4+proCol1+ cells were detected in all examined biopsy samples from CP patients. Serum levels of CXCL12 were also higher in CP patients than controls (P = 0.0056), and tissue‐infiltrating inflammatory cells intensely expressed CXCL12. Increased serum levels of Th2 cytokines (e.g., interleukin‐13 [IL‐13] and IL‐10) were found in patients, and immunohistochemistry revealed a dominant infiltration of GATA‐3+ cells, also indicating Th2 polarization; Th2‐skewed responses are known to promote fibrocyte differentiation.ConclusionOur findings indicate that fibrocytes are enriched in the peripheral blood of CP patients and infiltrate target lesions. The accumulation of fibrocytes in the pathologic tissue might be driven by CXCL12, and Th2‐skewed immune responses are likely to facilitate their differentiation.
Engineering of alcohol dehydrogenase 2 hybrid‐promoter architectures in Pichia pastoris to enhance recombinant protein expression on ethanol
Authors: Ergün Burcu Gündüz , Gasser Brigitte , Mattanovich Diethard , Çalık Pınar 
Published: June 2019

AbstractThe aim of this work is to increase recombinant protein expression in Pichia pastoris over the ethanol utilization pathway under novel‐engineered promoter variants (NEPVs) of alcohol dehydrogenase 2 promoter (PADH2) through the generation of novel regulatory circuits. The NEPVs were designed by engineering of transcription factor binding sites (TFBSs) determined by in silico analyses and manual curation systematically, by (a) single‐handedly replacement of specified TFBSs with synthetic motifs for Mxr1, Cat8, and Aca1 binding, and synthetic TATA‐box integration; and, (b) nucleosome optimization. PADH2‐Cat8‐L2 and PADH2‐Cat8‐L1 designed by the integration of synthetic Cat8 binding sites were superior, and then PADH2‐NucOpt. Compared to that with PADH2 at t = 20 hr of the fermentations, PADH2‐Cat8‐L2 allowed the highest increase in enhanced green fluorescent protein expression as 4.8‐fold on ethanol and 3.8‐fold on methanol; and, PADH2‐NucOpt upregulated the expression 1.5‐fold on ethanol and enhanced 3.2‐fold on methanol. Using the superior two tools, Cat8‐L2 and NucOpt, we designed PADH2‐NucOpt‐Cat8‐L2. With PADH2‐NucOpt‐Cat8‐L2, the expression in the fermentation of ethanol was upregulated 3.7‐fold that is distinctly higher than that with PADH2‐NucOpt but lower than that with PADH2‐Cat8‐L2; while on methanol compared to that with PADH2, the expression was enhanced 8.8‐fold. Extracellular recombinant human serum albumin production was also studied with PADH2‐Cat8‐L2 and PADH2‐NucOpt, and average recombinant human serum albumin yield (YP/X) on ethanol was 1.13 and 0.38 mg/gWCW, respectively; whereas with PADH2, YP/X was 0.26 mg/gWCW. We conclude that as upregulation of transcription and enhanced expression correlate with the sequence of synthetic motifs and their location in the hybrid‐promoter architectures of NEPVs in coordination with trans‐acting factors, which are the design parameters in the engineering of binding sites; the NEPVs generated promising recombinant protein production platforms with a high impact on industrial scale production processes, as well as would open up new avenues for research in P. pastoris.
Facile synthesis of (−)‐vibo‐quercitol from maltodextrin via an in vitro synthetic enzymatic biosystem
Authors: Bai Xue , Meng Dongdong , Wei Xinlei , Zhou Xigui , Lu Fuping , You Chun 
Published: June 2019

Abstract(−)‐vibo‐Quercitol (VQ: 1L‐1,2,4/3,5‐cyclohexanepentol), a form of deoxyinositol, is an alternative chiral building block in the synthesis of bioactive compounds to control diabetes. In this study, an adenosine triphosphate‐free in vitro synthetic enzymatic biosystem composed of five enzymes (including one enzyme for NADH regeneration) was constructed to produce VQ from maltodextrin in one‐pot. After optimization of reaction conditions, 7.6 g/L VQ was produced from 10 g/L maltodextrin with a product yield (mol/mol) of 77%, and 25.3 g/L VQ with a purity of 87% was produced from 50 g/L maltodextrin through simple scaling up of this nonfermentative enzymatic biosystem. Therefore, this study provides an economical and environmentally friendly method for the envisioned quercitol biosynthesis.
Morphology of Osteogenesis Imperfecta Collagen Mimetic Peptide Assemblies Correlates with the Identity of Glycine‐Substituting Residue
Authors: Yao Linyan , Liu Zhao , Yu Jingyuan , Luo Liting , Wang Jie , Xiao Jianxi 
Published: June 2019

AbstractOsteogenesis imperfecta (OI) is a hereditary bone disorder with various phenotypes ranging from mild multiple fractures to perinatal lethal cases, and it mainly results from the substitution of Gly by a bulkier residue in type I collagen. Triple‐helical peptide models of Gly mutations have been widely utilized to decipher the etiology of OI, although these studies are mainly limited to characterizing the peptide features, such as stability and conformation in the solution state. Herein, we have constructed a new series of triple‐helical peptides DD(GPO)5ZPO(GPO)4DD (Z=Ala, Arg, Asp, Cys, Glu, Ser, and Val) mimicking the most common types of observed OI cases. The inclusion of special terminal aspartic acids enables these collagen mimetic peptides to self‐assemble to form nanomaterials upon the trigger of lanthanide ions. We have for the first time systematically evaluated the effect of different OI mutations on the aggregated state of collagen mimetic peptides. We have revealed that the identity of the Gly‐substituting residue plays a determinant role in the morphology and secondary structure of the collagen peptide assemblies, showing that bulkier residues tend to result in a disruptive secondary structure and defective morphology, which lead to more severe OI phenotypes. These findings of osteogenesis imperfecta collagen mimetic peptides in the aggregation state provide novel perspectives on the molecular mechanism of osteogenesis imperfecta, and may aid the development of new therapeutic strategies.
Tying the knot: An uncommon complication
Authors: Boumpoulis Konstantinos , Chatzis Andrew C. , Balanika Marina , Milonakis Michael , Khoury Mazen 
Published: June 2019

AbstractCardiothoracic procedures require continuous hemodynamic monitoring and a fair proportion of these require the insertion of a pulmonary artery catheter, known also as Swan‐Ganz catheter. Given, however, the invasive nature of these procedures, unforeseen complications may ensue. Early recognition and appropriate handling are essential to minimize adverse outcomes.
Indolent Propionibacterium acnes infection associated with orthopedic hardware in the ankle: A case report and literature review
Authors: Arain Abdul R. , Sullivan Connor W. , Angelicola‐Richardson Kyle , Haddad Stefanos , Rosenbaum Andrew 
Published: June 2019

AbstractPropionibacterium acnes (P. acnes) infections of the foot and ankle are very rare and require a unique approach to prevention, diagnosis, and treatment. Clinicians should consider P. acnes as a cause for all late and indolent orthopedic infections, as appropriate surgical and medical management can result in a good outcome.
Insight into the Role of Water on the Methylation of Hexamethylbenzene in H‐SAPO‐34 from First Principle Molecular Dynamics Simulations
Authors: Bailleul Simon , Rogge Sven M. J. , Vanduyfhuys Louis , Van Speybroeck Veronique 
Published: June 2019

AbstractThe methylation of hexamethylbenzene with methanol is one of the key reactions in the methanol‐to‐olefins hydrocarbon pool reaction cycle taking place over the industrially relevant H‐SAPO‐34 zeolite. This methylation reaction can occur either via a concerted or via a stepwise mechanism, the latter being the preferred pathway at higher temperatures. Herein, we systematically investigate how a complex reaction environment with additional water molecules and higher concentrations of Brønsted acid sites in the zeolite impacts the reaction mechanism. To this end, first principle molecular dynamics simulations are performed using enhanced sampling methods to characterize the reactants and products in the catalyst pores and to construct the free energy profiles. The most prominent effect of the dynamic sampling of the reaction path is the stabilization of the product region where water is formed, which can either move freely in the pores of the zeolite or be stabilized through hydrogen bonding with the other protic molecules. These protic molecules also stabilize the deprotonated Brønsted acid site, created due to the formation of the heptamethylbenzenium cation, via a Grotthuss‐type mechanism. Our results provide fundamental insight in the experimental parameters that impact the methylation of hexamethylbenzene in H‐SAPO‐34, especially highlighting and rationalizing the crucial role of water in one of the main reactions of the aromatics‐based reaction cycle.
Recent Progress in Ruthenium Oxide‐Based Composites for Supercapacitor Applications
Authors: Majumdar Dipanwita , Maiyalagan Thandavarayan , Jiang Zhongqing 
Published: June 2019

AbstractElectrochemical energy storage has emerged as one of the principal topics of present‐day research to deal with the high energy demands of modern society. Accordingly, besides fuel cells and battery technologies, interesting and challenging results have been observed in the recent past, during the materialization of “supercapacitors” or “ultracapacitors”, which have provoked a sharp increase in research inclination to revisit this aspect of renewable and sustainable energy storage. Supercapacitor performances are largely dependent on electrode materials, the nature of the electrolyte used, and the range of voltage windows employed. Carbon‐based electrode materials have tunable properties such as electrical conductivity, extensive surface area, and faster electron transfer kinetics with low fabrication costs. But their specific capacitances are found to be too low for commercialization. Ruthenium dioxide (RuO2), owing to its high theoretical specific capacitance value (1400–2000 F g−1), has been extensively recognized as a favorable material for supercapacitor devices, but high production cost and agglomeration effects stand as high barriers preventing marketable usage. Consequently, RuO2‐based nanocomposites have been widely studied to optimize the material cost, with simultaneous improvement in the electrochemical performances. This Review describes comprehensively the recent progress in terms of the fabrication and design, electrochemical performance, and achievements of RuO2 and its nanocomposites as electrode materials for supercapacitors, which will be beneficial for further research designing high‐performance supercapacitor devices.
Physicochemical and Electrochemical Properties of 1,1,2,2‐Tetrafluoroethyl‐2,2,3,3‐Tetrafluoropropyl Ether as a Co‐Solvent for High‐Voltage Lithium‐Ion Electrolytes
Authors: Xia Lan , Lee Saixi , Jiang Yabei , Li Shiqi , Liu Zhaoping , Yu Linpo , Hu Di , Wang Shuhan , Liu Yitong , Chen George Z. 
Published: June 2019

AbstractAlthough high‐voltage positive electrode materials for high energy density lithium‐ion batteries have gained a great attention, the lack of compatible electrolytes with sufficiently high oxidative stability to deliver an excellent cycling ability restricts their practical application. Fluorinated solvents are considered as promising candidates for high‐voltage electrolyte solvents. In this study, we select 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether (TTE) with a high boiling point, low cost, and good SEI‐filming ability as a co‐solvent of fluoroethylene carbonate‐based electrolytes and extensively investigate its physicochemical and electrochemical properties for applications in high‐voltage lithium‐ion batteries. Our experimental results show that the TTE‐containing electrolyte exhibits not only a high oxidative stability up to 5.5 V (vs. Li/Li+), but also excellent wettability with the separator. In addition to high discharge capacity and increased coulombic efficiency of the Li/LiNi0.5Mn1.5O4 half‐cell assembled with the TTE‐containing electrolyte cycled between 3.0 and 4.9 V, the cell also displays a high rate capability. This work shows that partially fluorinated ethers, e. g., TTE, are promising co‐solvents for high‐voltage electrolytes that can enable commercial development of high energy density lithium‐ion batteries.
Facile Synthesis of Nanoporous Pt‐Encapsulated Ir Black as a Bifunctional Oxygen Catalyst via Modified Polyol Process at Room Temperature
Authors: Fang Dahui , Zhang Hongjie , He Liang , Geng Jiangtao , Song Wei , Sun Shucheng , Shao Zhigang , Yi Baolian 
Published: June 2019

AbstractThe exploitation of a bifunctional oxygen catalyst with high efficiency is crucial for a high‐performance unitized regenerative fuel cell (URFC). However, the existing bifunctional oxygen catalysts still suffer from low catalytic efficiency due to sluggish oxygen electrode reactions toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, we report on a facile synthesis of nanoporous Pt‐encapsulated Ir black with Pt/Ir mass ratio of 55/45 (Pt55@Ir45) via a newly modified polyol process at room temperature with the aid of water. The resulting Pt55@Ir45 catalyst demonstrated to be highly efficient and robust for both ORR and OER, relative to a mixture of commercial Pt and Ir black with Pt/Ir mass ratio of 50/50 (Pt50/Ir50). Mass activity of Pt55@Ir45 presented an 8.7‐ and 1.6‐fold increase toward ORR and OER, respectively, compared with the Pt50/Ir50 catalyst. The enhanced bifunctional performance was rationalized in terms of the maximized Pt utilization, achieved by the excellent dispersion of Pt nanoparticles, and the nanoporous Pt layer constructing a conductive network without impeding the transport of oxygen and water molecules. Our work demonstrates an effective means to encapsulate nanoporous Pt layers on Ir black for the fabrication of bifunctional oxygen catalysts.
Influence of Lithium and Lanthanum Treatment on TiO2 Nanofibers and Their Application in n‐i‐p Solar Cells
Authors: Ambroz Filip , Sathasivam Sanjayan , Lee Roxanna , Gadipelli Srinivas , Lin Chieh‐Ting , Xu Shengda , Poduval Radhika K. , Mclachlan Martyn A. , Papakonstantinou Ioannis , Parkin Ivan P. , Macdonald Thomas J. 
Published: June 2019

AbstractInvited for this month's cover picture is the group of Dr. Macdonald from the Department of Chemistry at University College London (UK). The cover picture shows a scanning electron microscopy image of lanthanum‐treated TiO2 nanofibers rendered to show a three‐dimensional representation of the nanostructured solar cell. This work shows that the addition of lithium and lanthanum cations causes minimal substitutional or interstitial doping of TiO2 nanofibers. In a solar cell, photovoltaic characteristics reveal that lanthanum treatment is beneficial, whereas lithium treatment is found to be detrimental to the device performance for both dye‐sensitized and perovskite solar cells. Read the full text of the Article at 10.1002/celc.201900532.
Asymmetric Hydrogenation of Aryl Perfluoroalkyl Ketones Catalyzed by Rhodium(III) Monohydride Complexes Bearing Josiphos Ligands
Authors: Brüning Fabian , Nagae Haruki , Käch Daniel , Mashima Kazushi , Togni Antonio 
Published: June 2019

AbstractThe asymmetric hydrogenation of 2,2,2‐trifluoroacetophenones and aryl perfluoroalkyl ketones was developed using a unique, well‐defined chloride‐bridged dinuclear rhodium(III) complex bearing Josiphos‐type diphosphine ligands. These complexes were prepared from [RhCl(cod)]2, Josiphos ligands, and hydrochloric acid. As catalyst precursors, they allow for the efficient and enantioselective synthesis (up to 99 % ee) of chiral secondary alcohols with perfluoroalkyl groups. This system does not require an activating base for the hydrogenation of 2,2,2‐trifluoroacetophenones. Additionally, the enantioselective C=O hydrogenations of 2‐phenyl‐3‐(haloacetyl)‐indoles, a class of privileged structures in medicinal chemistry, is reported for the first time.
Preparation and Characterisation of a Bis‐μ‐Hydroxo‐NiIII2 Complex
Authors: Spedalotto Giuseppe , Gericke Robert , Lovisari Marta , Farquhar Erik R. , Twamley Brendan , McDonald Aidan R. 
Published: June 2019

AbstractHydroxide‐bridged high‐valent oxidants have been implicated as the active oxidants in methane monooxygenases and other oxidases that employ bimetallic clusters in their active site. To understand the properties of such species, bis‐μ‐hydroxo‐NiII2 complex (1) supported by a new dicarboxamidate ligand (N,N′‐bis(2,6‐dimethyl‐phenyl)‐2,2‐dimethylmalonamide) was prepared. Complex 1 contained a diamond core made up of two NiII ions and two bridging hydroxide ligands. Titration of the 1 e− oxidant (NH4)2[CeIV(NO3)6] with 1 at −45 °C showed the formation of the high‐valent species 2 and 3, containing NiIINiIII and NiIII2 diamond cores, respectively, maintaining the bis‐μ‐hydroxide core. Both complexes were characterised using electron paramagnetic resonance, X‐ray absorption, and electronic absorption spectroscopies. Density functional theory computations supported the spectroscopic assignments. Oxidation reactivity studies showed that bis‐μ‐hydroxide‐NiIII2 3 was capable of oxidizing substrates at −45 °C at rates greater than that of the most reactive bis‐μ‐oxo‐NiIII complexes reported to date.