bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioseparation of N‐acetyl‐glutamine enantiomers by LC–MS/MS and its application to a plasma protein binding study
Authors: Gao Lei , Xue Yunwen , Zhang Zunjian , Tian Yuan 
Published: April 2019

AbstractA novel chiral method was developed and validated to determine N‐acetyl‐glutamine (NAG) enantiomers by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Enantioseparation was achieved on a Chiralpak QD‐AX column (150 × 4.6 mm i.d., 5 μm) using methanol–water (50 mm ammonium formate, pH 4.3; 70:30, v/v) at a flow rate of 500 μL/min. The detection was operated with an electrospray ionization source interface in positive mode. The ion transition for NAG enantiomers was m/z 189.0 → 130.0. The retention time of N‐acetyl‐l‐glutamine and N‐acetyl‐d‐glutamine were 15.2 and 17.0 min, respectively. Calibration curves were linear over the range of 0.02–20 μg/mL with r > 0.99. The deviation of accuracy and the coefficient of variation of within‐run and between‐run precision were within 10% for both enantiomers, except for the lower limit of quantification (20 ng/mL), where they deviated <15%. The recovery was >88% and no obvious matrix effect was observed. This method was successfully applied to investigate the plasma protein binding of NAG enantiomers in rats. The results showed that the plasma protein binding of NAG enantiomers was stereoselective. The assay method also exhibited good application prospects for the clinical monitoring of free drugs in plasma.
Biogenic approach to synthesize rod shaped Gd2O3 nanoparticles and its optimization using response surface methodology‐Box–Behnken design model
Authors: Surendra Tammineni Venkata , Mohana Roopan Selvaraj , Khan Maksudur R. 
Published: April 2019

AbstractThe rare earth metal oxide nanoparticles such as gadolinium oxide nanoparticles (Gd2O3 NPs) have been synthesized by green synthesis process using methanolic extract of Moringa oleifera (M oleifera) peel. In this process, the Gd2O3 NPs formation was observed at 280–300 nm in UV–Vis spectroscopy. The XRD pattern of the synthesized Gd2O3 NPs was exactly matched with JCPDS No 3‐065‐3181which confirms the crystalline nature of Gd2O3 NPs. In addition, Energy‐dispersive X‐ray spectroscopy (EDX) analysis was stated that Gd and O elements were present as 70.31 and 29.69%, respectively in Gd2O3 NPs. The SEM and TEM analysis were said Gd2O3 NPs are in rod shape and 26 ± 2 nm in size. Further the synthesized Gd2O3 NPs were confirmed by X‐ray photoemission spectroscopy (XPS). The synthesized Gd2O3 NPs were further examined for anti‐fungal activity against Alternaria saloni (A saloni) and Sclerrotium rolfsii (S rolfsii) and it showed moderate activity. Also, Gd2O3 NPs evaluated as good antibacterial agent against different Gram +ve and Gram −ve bacteria. Moreover, the toxicity of the Gd2O3 NPs on red blood cells (RBCs) of the human blood was determined using hemolytic assay, the obtained results were stated the synthesized Gd2O3 NPs are nontoxic to the human erythrocytes. The photocatalytic activity against malachite green (MG) dye was tested and confirmed as 92% of dye was degraded within 2 hr by Gd2O3 NPs. The results were stated the green synthesized Gd2O3 NPs are good anti‐fungal agents, nontoxic and we can use as a photocatalyst. Copyright © 2019 John Wiley & Sons, Ltd.
Biochemical and Structural Characterization of XoxG and XoxJ and Their Roles in Lanthanide‐Dependent Methanol Dehydrogenase Activity
Authors: Featherston Emily R. , Rose Hannah R. , McBride Molly J. , Taylor Ellison M. , Boal Amie K. , Cotruvo Joseph A. 
Published: April 2019

AbstractLanthanide (Ln)‐dependent methanol dehydrogenases (MDHs) have recently been shown to be widespread in methylotrophic bacteria. Along with the core MDH protein, XoxF, these systems contain two other proteins, XoxG (a c‐type cytochrome) and XoxJ (a periplasmic binding protein of unknown function), about which little is known. In this work, we have biochemically and structurally characterized these proteins from the methyltroph Methylobacterium extorquens AM1. In contrast to results obtained in an artificial assay system, assays of XoxFs metallated with LaIII, CeIII, and NdIII using their physiological electron acceptor, XoxG, display Ln‐independent activities, but the Km for XoxG markedly increases from La to Nd. This result suggests that XoxG′s redox properties are tuned specifically for lighter Lns in XoxF, an interpretation supported by the unusually low reduction potential of XoxG (+172 mV). The X‐ray crystal structure of XoxG provides a structural basis for this reduction potential and insight into the XoxG–XoxF interaction. Finally, the X‐ray crystal structure of XoxJ reveals a large hydrophobic cleft and suggests a role in the activation of XoxF. These studies enrich our understanding of the underlying chemical principles that enable the activity of XoxF with multiple lanthanides in vitro and in vivo.
Recent Advances in Solvent‐Free Asymmetric Catalysis
Authors: Tavakolian Mina , Vahdati‐Khajeh Saleh , Asgari Sepideh 
Published: April 2019

AbstractIt is well‐known that solvent is one of the most important factors that affect chemical reactions. This factor is more noticeable and impressive in the asymmetric reactions where the effective interaction of reactants and the creation of a uniform chiral environment is necessary. Nevertheless, when reactions are carried out in the absence of solvent, some privileged advantages such as easy work up, short reaction time, lack of waste solvents, and following the green chemistry principles, are appeared. Therefore, according to the importance of asymmetric synthesis and green chemistry, solvent‐free asymmetric catalysis can act as a considerable and necessary subject in synthetic chemistry. In this review, we have a survey on the solvent‐free asymmetric synthesis by the use of either homogeneous or heterogeneous chiral catalysts.
A New Route to Cyclohexanone using H2CO3 as a Molecular Catalytic Ligand to Boost the Thorough Hydrogenation of Nitroarenes over Pd Nanocatalysts
Authors: Zhao Tian‐Jian , Zhang Jun‐Jun , Zhang Bing , Liu Yong‐Xing , Lin Yun‐Xiao , Wang Hong‐Hui , Su Hui , Li Xin‐Hao , Chen Jie‐Sheng 
Published: April 2019

AbstractCarbon dioxide has been important in green chemistry, especially in catalytic and chemical engineering applications. While exploring CO2 to produce cyclohexanone for nylon or nylon 66 that is currently produced with low yields using harsh catalytic methods, we made the exciting discovery that carbonic acid, generated from dissolved CO2 in water, was utilized as molecular catalytic ligand to produce cyclohexanone via the hydrogenation of nitrobenzene in aqueous solution that uses Pd catalysts with a total yield higher than 90 %. Importantly, the gaseous nature of catalytic ligand H2CO3 profoundly simplifies post‐catalysis cleanup unlike liquid or solid catalysts. This new green catalysis strategy demonstrated the universality for hydrogenation of aromatic compounds like aniline and N‐methylaniline and could be broadly applicable in other catalytic field like artificial photosynthesis and electrocatalytic organic synthesis.
How Do Structurally Distinct Au/α‐Fe2O3 Interfaces Determine Surface OH/H2O reactivity, Intermediate Evolution, and Product Formation in Low‐temperature Water‐gas Shift Reaction?
Authors: Gu Lingli , Zeng Yiqiang , Feng Yina , Jiang Wu , Ji Weijie , Arandiyan Hamidreza , Au Chak‐Tong 
Published: April 2019

AbstractThree structurally distinct interfaces, i. e. Au/α‐Fe2O3‐THB‐Air, Au/α‐Fe2O3‐HS‐Air, and Au/α‐Fe2O3‐QC‐Air, with the major substrate facet being {113}, {001}, and {012} respectively, were controllably prepared. The low temperature water gas shift (WGS) reaction (100–260 °C) was applied to these unique systems to reveal how these structurally distinct interfaces can impact on the reaction behavior. With the detailed performance evaluation plus the characterizations of CO‐TPSR, XPS, and in situ‐FTIR in particular, the correlations between the evolution of different intermediates and the distinct catalytic behaviors have been established. The substrate facet structure and the Au entity largely determine the form and reactivity of surface OH/H2O species which in turn determine the formation of different intermediates and eventually the product formation. The Au/α‐Fe2O3‐THB‐Air is enriched with oxygen vacant sites, favorable for dissociative adsorption of H2O, carboxyl intermediate formation and H2 production. The Au/α‐Fe2O3‐HS‐Air is enriched with surface lattice oxygen, favorable for molecular adsorption of H2O, formate intermediate formation, and CO2 production. The Au/α‐Fe2O3‐QC‐Air interface is enriched with surface Fe sites, favorable for dissociative adsorption of H2O and evolution of stable carboxyl intermediate as well as isolated OH species at low reaction temperatures. The findings are informative to control the interfacial structure for the WGS and other reactions.
Construction of a Stable Crystalline Polyimide Porous Organic Framework for C2H2/C2H4 and CO2/N2 Separation
Authors: Jiang Lingchang , Wang Pengyuan , Li Meiping , Zhang Panpan , Li Jialu , Liu Jia , Ma Yanhang , Ren Hao , Zhu Guangshan 
Published: April 2019

AbstractUtilization of porous materials for gas capture and separation is a hot research topic. Removal of acetylene (C2H2) from ethylene (C2H4) is important in the oil refining and petrochemical industries, since C2H2 impurities deactivate the catalysts and terminate the polymerization of C2H4. Carbon dioxide (CO2) emission from power plants contributes to global climate change and threatens the survival of life on this planet. Herein, 2D crystalline polyimide porous organic framework PAF‐120, which was constructed by imidization of linear naphthalene‐1,4,5,8‐tetracarboxylic dianhydride and triangular 1,3,5‐tris(4‐aminophenyl)benzene, showed significant thermal and chemical stability. Low‐pressure gas adsorption isotherms revealed that PAF‐120 exhibits good selective adsorption of C2H2 over C2H4 and CO2 over N2. At 298 K and 1 bar, its C2H2 and CO2 selectivities were predicted to be 4.1 and 68.7, respectively. More importantly, PAF‐120 exhibits the highest selectivity for C2H2/C2H4 separation among porous organic frameworks. Thus PAF‐120 could be a suitable candidate for selective separation of C2H2 over C2H4 and CO2 over N2.
Mitochondria Targeting Fluorescent Probes Based on through Bond‐Energy Transfer for Mutually Imaging Signaling Molecules H2S and H2O2
Authors: Sun Jian , Li Xiao , Cao Jia , Sun Qi , Zhang Yajie , Wang Xuewei , Wu Tiantian , Hu Xiantao , Feng Fude 
Published: April 2019

AbstractReactive signaling molecules participate in varieties of biochemical reactions, and methods to detect their mutual existence and crosstalk are in urgent demand. A benzothiadiazole‐based handle was designed to fluorescently respond to the co‐existence of H2S and H2O2 under pseudo‐physiological conditions on a basis of a thiyl‐radical‐mediated mechanism that accounts for the rapid and efficient domino‐like reaction processes. Then the handle motif was attached to a rhodamine moiety by means of an ethynylene linkage, and achieved a significant H2S–H2O2 mutual response in the mitochondria of living cells. Theoretical calculations supported that a through bond energy transfer mechanism contributes to the drastic fluorescence response.
Catalytic Chemosensing Assay for Selective Detection of Methyl Parathion Organophosphate Pesticide
Authors: Zheng Anxun , Shen Chang , Tang Qian , Gong Cheng‐Bin , Chow Cheuk‐Fai 
Published: April 2019

AbstractHerein, a catalytic chemosensing assay (CCA), based on a bimetallic complex, [RuII(bpy)2(CN)2]2(CuII)2 (bpy=2,2′‐bipyridine), is described. This complex integrates a task‐specific catalyst (CuI‐catalyst) and a signaling unit ([RuII(bpy)2(CN)2]) to specifically hydrolyze methyl parathion, a highly toxic organophosphate (OP) pesticide. The bimetallic complex catalyzed the hydrolysis of the phosphate ester to generate o,o‐dimethyl thiophosphate (DTP) anion and 4‐nitrophenolate. Intrinsically, 4‐nitrophenolate absorbed UV/Vis light at λmax=400 nm, creating the first level of the chemosensing signal. DTP interacted with the original complex to displace the chromophore, [RuII(bpy)2(CN)2], which was monitored by spectrofluorometry; this was classified as the second level of chemosensing signal. By integrating both spectroscopic and spectrofluorometric signals with a simple AND logic gate, only methyl parathion was able to provide a positive response. Other aromatic and aliphatic OP pesticides (diazinon, fenthion, meviphos, terbufos, and phosalone) and 4‐nitrophenyl acetate provided negative responses. Furthermore, owing to the metal‐catalyzed hydrolysis of methyl parathion, the CCA system led to the detoxification of the pesticide. The CCA system also demonstrated its catalytic chemosensing properties in the detection of methyl parathion in real samples, including tap water, river water, and underground water.
Chemo‐ and Regioselective Catalyst‐Controlled Carbocyclization of Alkynyl Ketones: Rapid Synthesis of 1‐Indanones and 1‐Naphthols
Authors: Song Liangliang , Tian Guilong , Van der Eycken Erik V. 
Published: April 2019

AbstractA catalyst‐controlled intramolecular carbocyclization of 2‐alkynyl aryl ketones is presented. Under rhodium(III) catalysis, 1‐indanones are formed through 5‐exo‐dig carbocyclizations with exclusive chemo‐, regio‐ and stereoselectivity. When catalyzed by copper(I), 1‐naphthols are obtained through 6‐endo‐dig carbocyclizations with exclusive chemo‐ and regioselectivity.
Enantiomeric resolution, thermodynamic parameters, and modeling of clausenamidone and neoclausenamidone on polysaccharide‐based chiral stationary phases
Authors: Luo Xuna , Fang Chengqiao , Mi Junru , Xu Jingzi , Lin Hansen 
Published: April 2019

AbstractThe aim of the paper is to describe a new synthesis route to obtain synthetic optically active clausenamidone and neoclausenamidone and then use high‐performance liquid chromatography (HPLC) to determine the optical purities of these isomers. In the process, we investigated the different chromatographic conditions so as to provide the best separation method. At the same time, a thermodynamic study and molecular simulations were also carried out to validate the experimental results; a brief probe into the separation mechanism was also performed. Two chiral stationary phases (CSPs) were compared with separate the enantiomers. Elution was conducted in the organic mode with n‐hexane and iso‐propanol (IPA) (80/20 v/v) as the mobile phases; the enantiomeric excess (ee) values of the synthetic R‐clausenamidone and S‐clausenamidone and R‐neoclausenamidone and S‐ neoclausenamidone were higher than 99.9%, and the enantiomeric ratio (er) values of these isomers were 100:0. Enantioselectivity and resolution (α and Rs, respectively) levels with values ranging from 1.03 to 1.99 and from 1.54 to 17.51, respectively, were achieved. The limits of detection and quantitation were 3.6 to 12.0 and 12.0 to 40.0 ug/mL, respectively. In addition, the thermodynamics study showed that the result of the mechanism of chiral separation was enthalpically controlled at a temperature ranging from 288.15 to 308.15 K. Furthermore, docking modeling showed that the hydrogen bonds and π‐π interactions were the major forces for chiral separation. The present chiral HPLC method will be used for the enantiomeric resolution of the clausenamidone derivatives.
Systematic Experimental Study on Quantum Sieving of Hydrogen Isotopes in Metal‐Amide‐Imidazolate Frameworks with narrow 1‐D Channels
Authors: Mondal Suvendu Sekhar , Kreuzer Alex , Behrens Karsten , Schütz Gisela , Holdt Hans‐Jürgen , Hirscher Michael 
Published: April 2019

AbstractQuantum sieving of hydrogen isotopes is experimentally studied in isostructural hexagonal metal‐organic frameworks having 1‐D channels, named IFP‐1, −3, −4 and −7. Inside the channels, different molecules or atoms restrict the channel diameter periodically with apertures larger (4.2 Å for IFP‐1, 3.1 Å for IFP‐3) and smaller (2.1 Å for IFP‐7, 1.7 Å for IFP‐4) than the kinetic diameter of hydrogen isotopes. From a geometrical point of view, no gas should penetrate into IFP‐7 and IFP‐4, but due to the thermally induced flexibility, so‐called gate‐opening effect of the apertures, penetration becomes possible with increasing temperature. Thermal desorption spectroscopy (TDS) measurements with pure H2 or D2 have been applied to study isotope adsorption. Further TDS experiments after exposure to an equimolar H2/D2 mixture allow to determine directly the selectivity of isotope separation by quantum sieving. IFP‐7 shows a very low selectivity not higher than S=2. The selectivity of the materials with the smallest pore aperture IFP‐4 has a constant value of S≈2 for different exposure times and pressures, which can be explained by the 1‐D channel structure. Due to the relatively small cavities between the apertures of IFP‐4 and IFP‐7, molecules in the channels cannot pass each other, which leads to a single‐file filling. Therefore, no time dependence is observed, since the quantum sieving effect occurs only at the outermost pore aperture, resulting in a low separation selectivity.
Electronically Tuned Asymmetric meso‐Substituted Porphyrins for p‐Type Solar Cells
Authors: Grzegorzek Norbert , Zieleniewska Anna , Schür Annika , Maichle‐Mössmer Cäcilia , Killian Manuela S. , Guldi Dirk M. , Chernick Erin T. 
Published: April 2019

AbstractA series of electronically tuned asymmetric porphyrins have been synthesized for use in p‐type solar cells. The porphyrin derivatives were strategically designed with electron‐withdrawing capability and an electronic dipole gradient to aid in electron‐harvesting capacity from a nickel oxide cathode. Specifically, the porphyrins were substituted at the meso position with different arrangements of the electron‐withdrawing pentafluorobenzene moiety, electron‐donating/coordinating 4‐pyridyl ligand, and an electron withdrawing/synthetically modifiable 4‐cyanophenyl unit. Two distinct free‐base porphyrins were synthesized, one of which was further metallated with nickel(II). The porphyrins were fully characterized and their electronic properties explored experimentally by electrochemistry, and both steady state and time‐resolved spectroscopy. Finally, the porphyrins were incorporated into a p‐type solar cell device utilizing NiO as the cathode, and demonstrating a preliminary maximum performance of η(%)=0.082 and IPCEMAX(%)=26.0 without co‐sensitization.
Cytomorphologic features of malignant solitary fibrous tumor with mediastinal involvement sampled by endoscopic and endobronchial ultrasound‐guided fine‐needle aspiration: A comparison of two cases
Authors: Hupp Meghan , Najmuddin Mufaddal , Dincer Huseyin Erhan , Mallery James Shawn , Amin Khalid , Stewart Jimmie 
Published: April 2019

AbstractSolitary fibrous tumor (SFT) is an uncommon fibroblastic neoplasm with considerable risk of local recurrence. SFT is histologically characterized by bland spindled‐to‐epithelioid cells in alternating hyper‐ and hypocellular zones, a “patternless pattern,” ectatic “staghorn” vessels with variable edematous perivascular stroma, and thick ropey collagen. Cytologically, smears are variably cellular with spindled‐to‐epithelioid cells with oval nuclei, wispy cytoplasm, multiple inconspicuous nucleoli, and occasional nuclear pseudoinclusions. Small vessels and bare/stripped nuclei are generally present while mild atypia is not uncommon. STAT6 nuclear expression is the most useful immunohistochemical stain and is the product of a NAB2‐STAT6 gene fusion. SFTs with mediastinal involvement may be diagnostically challenging due to proximity to vital structures and anticipated patient risks. Endobronchial and endoscopic ultrasound‐guided fine‐needle aspiration (EBUS/EUS‐FNA) are minimally‐invasive tissue sampling methods that provide diagnostic material while minimizing patient risk, and the mediastinum is accessible by both procedures. Small aspirate samples and SFT nonspecific features can compound the diagnostic difficulty, although familiarity with the cytologic, morphologic, immunophenotypic, and genetic features of SFTs assist the pathologist in confirming the diagnosis. Pathologists must also be aware of high‐risk SFT features to ensure appropriate therapy and management. Case #1 describes a recurrent mediastinal SFT with high‐risk features sampled by EUS‐FNA. Case #2 describes a primary diagnosis of mediastinal SFT with malignant behavior made on an EBUS‐FNA specimen.
Tissue resident T cell memory or how the magnificent seven are chilling in the bone
Authors: Zens Kyra , Münz Christian 
Published: April 2019

AbstractFollowing infection, tissue‐resident memory T cells (Trm) are thought to be left behind at sites of antigen encounter to protect affected tissues against subsequent reinfection. In this issue of the European Journal of Immunology, however, Pascutti et al. demonstrate that both murine and human CD8+ Trm specific to seven different pathogens, including systemic, skin, and lung tissue‐localized pathogens, accumulate in the bone marrow (BM). These cells have a CD69+ phenotype, develop independently of local antigen, and require IL‐15, Blimp‐1, and Hobit for their differentiation and maintenance. Following restimulation, these cells expand and rapidly produce cytokines. While some of these responses may protect the BM from infection, the consideration that some of these pathogens or their antigens might never reach the BM suggests additional functional roles of BM Trm, possibly in supporting hematopoietic functions via cytokine production following infection. It will be further interesting to determine whether BM Trm contribute to the circulating effector pool following reinfection with tissue‐localized or systemic pathogens and whether these cells can be elicited by vaccination.
The Synthesis of Chitosan Decorated Reduced Graphene Oxide‐Ferrocene Nanocomposite and its Application in Electrochemical Detection Rhodamine B
Authors: Yang Xing , Niu Xiaohui , Mo Zunli , Liu Nijuan , Guo Ruibin , Zhao Pan , Liu Zhenyu , Ouyang Meixuan 
Published: April 2019

AbstractChitosan (CS) decorated reduced graphene oxide‐Ferrocene nanocomposite (RGO−Fc−CS) was synthesized by a one‐pot reaction. In the synthesis process of RGO−Fc−CS, GO−Fc was successfully self‐assembled via the π–π interaction, which had the features of large surface area and the high load. Then GO‐Fc and CS linked via one‐pot under alkaline conditions. The FT−IR, TGA, SEM were employed to characterize the successful synthesis of RGO−Fc−CS composites. A miniature electrochemical system was fabricated by RGO−Fc−CS modified glassy carbon electrode (expressed as RGO−Fc−CS/GCE) for the sensitive detection of RhB enantiomers via DPV. Electrochemical results revealed that the RGO−Fc−CS/GCE exhibited high molecular recognition toward RhB. Due to the synergy between the RGO−Fc and CS, the RGO−Fc−CS/GCE showed a linear range of 0.001–70 μM with a LOD of 0.5 nM, indicating that RGO−Fc−CS/GCE has broad application prospects to simplify monitor RhB real‐time.