bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantification of Noncovalent Interactions in Azide–Pnictogen, –Chalcogen, and –Halogen Contacts
Authors: Bursch Markus , Kunze Lukas , Vibhute Amol M. , Hansen Andreas , Sureshan Kana M. , Jones Peter G. , Grimme Stefan , Werz Daniel B. 
Published: October 2020

AbstractThe noncovalent interactions between azides and oxygen‐containing moieties are investigated through a computational study based on experimental findings. The targeted synthesis of organic compounds with close intramolecular azide–oxygen contacts yielded six new representatives, for which X‐ray structures were determined. Two of those compounds were investigated with respect to their potential conformations in the gas phase and a possible significantly shorter azide–oxygen contact. Furthermore, a set of 44 high‐quality, gas‐phase computational model systems with intermolecular azide–pnictogen (N, P, As, Sb), –chalcogen (O, S, Se, Te), and –halogen (F, Cl, Br, I) contacts are compiled and investigated through semiempirical quantum mechanical methods, density functional approximations, and wave function theory. A local energy decomposition (LED) analysis is applied to study the nature of the noncovalent interaction. The special role of electrostatic and London dispersion interactions is discussed in detail. London dispersion is identified as a dominant factor of the azide–donor interaction with mean London dispersion energy‐interaction energy ratios of 1.3. Electrostatic contributions enhance the azide–donor coordination motif. The association energies range from −1.00 to −5.5 kcal mol−1.
Is it an Acid or Not? – The Puzzle of the Structure of Vitamin C
Authors: Streller Sabine 
Published: October 2020

AbstractDie Aufklärung der Struktur von Vitamin C war eine große Herausforderung für Wissenschaftler Anfang der 1930er Jahre. Zahlreiche Ergebnisse über die Analyse von Vitamin C lagen bereits vor und die wesentlichen chemischen Eigenschaften waren bekannt. Doch genau die Beziehung zwischen Eigenschaften und Struktur dieser Verbindung erwies sich lange Zeit als rätselhaft. Die Mühen und Fortschritte der Wissenschaftler sind in diversen Publikationen so dokumentiert, dass sie auch für Schülerinnen und Schüler nachvollziehbar und verständlich sind. Damit eignet sich das Thema Strukturaufklärung von Vitamin C besonders, um im Chemieunterricht nach dem historisch‐problemorientierten Unterrichtsverfahren aufbereitet zu werden. In diesem Beitrag werden die historische Entwicklung der Strukturaufklärung von Vitamin C sowie eine konzipierte Unterrichtsreihe vorgestellt.
Synthesis and Structure−Activity Relationships of Imidazopyridine/Pyrimidine‐ and Furopyridine‐Based Anti‐infective Agents against Trypanosomiases
Authors: Silva Daniel G. , Junker Anna , de Melo Shaiani M. G. , Fumagalli Fernando , Gillespie J. Robert , Molasky Nora , Buckner Frederick S. , Matheeussen An , Caljon Guy , Maes Louis , Emery Flavio S. 
Published: October 2020

AbstractNeglected tropical diseases remain among the most critical public health concerns in Africa and South America. The drug treatments for these diseases are limited, which invariably leads to fatal cases. Hence, there is an urgent need for new antitrypanosomal drugs. To address this issue, a large number of diverse heterocyclic compounds were prepared. Straightforward synthetic approaches tolerated pre‐functionalized structures, giving rise to a structurally diverse set of analogs. We report on a set of 57 heterocyclic compounds with selective activity potential against kinetoplastid parasites. In general, 29 and 19 compounds of the total set could be defined as active against Trypanosoma cruzi and T. brucei brucei, respectively (antitrypanosomal activities <10 μM). The present work discusses the structure−activity relationships of new fused‐ring scaffolds based on imidazopyridine/pyrimidine and furopyridine cores. This library of compounds shows significant potential for anti‐trypanosomiases drug discovery.
Configuration Flipping in Distal Pocket of Multidrug Transporter MexB Impacts the Efflux Inhibitory Mechanism
Authors: Kumar Roy Rakesh , Patra Niladri 
Published: October 2020

AbstractMexAB‐OprM efflux pumps, found in Pseudomonas aeruginosa, play a major role in drug resistance by extruding out drugs and antibiotic molecules from cells. Inhibitors are used to cease the potency of the efflux pumps. In this study, in‐silico models are used to investigate the nature of the binding pocket of the MexAB‐OprM efflux pump. First, we have performed classical molecular dynamics (MD) simulations to shed light on different aspects of protein–inhibitor interaction in the binding pocket of the pump. Using classical MD simulations, quantum mechanics/molecular mechanics (QM/MM), and various types of analyses, it is found that D13‐9001 has a higher binding affinity towards the binding pocket compared to D1 and D2; the results are in sync with the experimental dat. Two stable configurations of D13‐9001 are discovered inside the distal pocket which could be one of the primary reasons for the greater efficacy of D13‐9001. The free energy barrier upon changing one state to another is calculated by employing umbrella sampling method. Finally, F178 is mutated to have the complete picture as it contributes significantly to the binding energy irrespective of the three inhibitors. Our results may help to design a new generation of inhibitors for such an efflux pump.
Tailoring Particle‐Enzyme Nanoconjugates for Biocatalysis at the Organic‐Organic Interface
Authors: Sun Zhiyong , Cai Meng , Hübner René , Ansorge‐Schumacher Marion B. , Wu Changzhu 
Published: October 2020

AbstractNonaqueous Pickering emulsions (PEs) are a powerful platform for catalysis design, offering both a large interface contact and a preferable environment for water‐sensitive synthesis. However, up to now, little progress has been made to incorporate insoluble enzymes into the nonaqueous system for biotransformation. Herein, we present biocatalytically active nonaqueous PEs, stabilized by particle‐enzyme nanoconjugates, for the fast transesterification and esterification, and eventually for biodiesel synthesis. Our nanoconjugates are the hybrid biocatalysts tailor‐made by loading hydrophilic Candida antarctica lipase B onto hydrophobic silica nanoparticles, resulting in not only catalytically active but highly amphiphilic particles for stabilization of a methanol‐decane emulsion. The enzyme activity in these PEs is significantly enhanced, ca. 375‐fold higher than in the nonaqueous biphasic control. Moreover, the PEs can be multiply reused without significant loss of enzyme performance. With this proof‐of‐concept, this system can be expanded for many advanced syntheses using different enzymes in the future.
Transition Metal and Nitrogen Co‐Doped Carbon‐based Electrocatalysts for the Oxygen Reduction Reaction: From Active Site Insights to the Rational Design of Precursors and Structures
Authors: Wang Dan , Pan Xiaona , Yang Peixia , Li Ruopeng , Xu Hao , Li Yun , Meng Fan , Zhang Jinqiu , An Maozhong 
Published: October 2020

AbstractConsidering the urgent requirement for clean and sustainable energy, fuel cells and metal‐air batteries have emerged as promising energy storage and conversion devices to alleviate the worldwide energy challenges. The key step in accelerating the sluggish oxygen reduction reaction (ORR) kinetics at the cathode is to develop cost‐effective and high‐efficiency non‐precious metal catalysts, which can be used to replace expensive Pt‐based catalysts. Recently, the transition metal and nitrogen co‐doped carbon (M−Nx/C) materials with tailored morphology, tunable composition, and confined structure show great potential in both acidic and alkaline media. Herein, the mechanism of ORR is provided, followed by recent efforts to clarify the actual structures of active sites. Furthermore, the progress of optimizing the catalytic performance of M−Nx/C catalysts by modulating nitrogen‐rich precursors and porous structure engineering is highlighted. The remaining challenges and development prospects of M−Nx/C catalysts are also outlined and evaluated.
Depolymerization of Lignin into Monophenolics by Ferrous/Persulfate Reagent under Mild Conditions
Authors: Bao Hanxi , Sagues William J. , Wang Yigui , Peng Wenbo , Zhang Lin , Yang Shunchang , Xiao Dequan , Tong Zhaohui 
Published: October 2020

AbstractThis study aimed to use a persulfate together with transition metal ions as the reagent to effectively depolymerize lignin into monophenolic compounds under mild conditions (ambient pressure, temperature <100 °C). The Box‐Behnken experimental design in combination with the response surface methodology was applied to obtain optimized reaction conditions. The results showed that this reagent could depolymerize up to 99 % of lignin dimers to mainly veratraldehyde. This reaction also successfully depolymerized industrial lignins with a high yield of phenolic oils and monophenolic compounds. Quantum chemistry calculations using the density functional theory level indicated that the persulfate free radical attacks Cβto break the β‐O‐4 bond of lignin through a five‐membered ring mechanism. This mechanism using persulfate free radicals has a lower activation barrier than that using hydroxyl radicals. Gel permeation chromatography and 2D‐NMR spectroscopy demonstrated the effective cleavage of the β‐O‐4 bonds of lignin after depolymerization.
Emulsion Polymerizations for a Sustainable Preparation of Efficient TEMPO‐based Electrodes
Authors: Muench Simon , Gerlach Patrick , Burges René , Strumpf Maria , Hoeppener Stephanie , Wild Andreas , Lex‐Balducci Alexandra , Balducci Andrea , Brendel Johannes C. , Schubert Ulrich S. 
Published: October 2020

AbstractOrganic polymer‐based batteries represent a promising alternative to present‐day metal‐based systems and a valuable step toward printable and customizable energy storage devices. However, most scientific work is focussed on the development of new redox‐active organic materials, while straightforward manufacturing and sustainable materials and production will be a necessary key for the transformation to mass market applications. Here, a new synthetic approach for 2,2,6,6‐tetramethyl‐4‐piperinidyl‐N‐oxyl (TEMPO)‐based polymer particles by emulsion polymerization and their electrochemical investigation are reported. The developed emulsion polymerization protocol based on an aqueous reaction medium allowed the sustainable synthesis of a redox‐active electrode material, combined with simple variation of the polymer particle size, which enabled the preparation of nanoparticles from 35 to 138 nm. Their application in cell experiments revealed a significant effect of the size of the active‐polymer particles on the performance of poly(2,2,6,6‐tetramethyl‐4‐piperinidyl‐N‐oxyl methacrylate) (PTMA)‐based electrodes. In particular rate capabilities were found to be reduced with larger diameters. Nevertheless, all cells based on the different particles revealed the ability to recover from temporary capacity loss due to application of very high charge/discharge rates.
CTRP4 acts as an anti‐inflammatory factor in macrophages and protects against endotoxic shock
Authors: Cao Lulu , Tan Weifeng , Chen Wei , Huang He , He Minwei , Li Qi , Zhu Xiaoxin , Wang Lu 
Published: October 2020

AbstractDespite the availability of antibiotics, current therapies to treat sepsis are still ineffective and many clinical trials aimed at neutralizing specific inflammatory cytokines have failed, suggesting the urgent need for new treatments. Using two models of LPS‐induced endotoxemia and cecal ligation and puncture (CLP)–induced sepsis, we investigated the effects of C1q/TNF‐related protein 4(CTRP4) on septic lethality and sepsis‐induced inflammation. The effects of CTRP4 on survival, inflammation, organ damage, and bacterial clearance were assessed. Here, we found that CTRP4 decreased the mortalities of mice and alleviated pathological lung injury in mice model. In vivo depletion and adoptive transfer studies showed CTRP4‐expressing macrophages as the key cell type inhibiting LPS‐induced septic shock. The mechanism associated with the CTRP4 deficiency involved promoting of TLR4 internalization and activation of downstream pathways that resulted in a lethal, prolonged proinflammatory cytokine storm. Treatment of macrophages with exogenous CTRP4 abrogated proinflammatory cytokine production. Our results showed CTRP4 regulates inflammatory response and could be a promising strategy to treat septic shock.
Storm Event–Driven Occurrence and Transport of Dissolved and Sorbed Organic Micropollutants and Associated Effects in the Ammer River, Southwestern Germany
Authors: Müller Maximilian E. , Zwiener Christian , Escher Beate I. 
Published: October 2020

Abstract
Storm events lead to agricultural and urban runoff, to mobilization of contaminated particulate matter, and to input from combined sewer overflows into rivers. We conducted time-resolved sampling during a storm event at the Ammer River, southwest Germany, which is representative of small river systems in densely populated areas with a temperate climate. Suspended particulate matter (SPM) and water from 2 sampling sites were separately analyzed by a multi-analyte liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for 97 environmentally relevant organic micropollutants and with 2 in vitro bioassays. Oxidative stress response (AREc32) may become activated by various stressors covering a broad range of physicochemical properties and induction of aryl hydrocarbon receptor–chemical-activated luciferase gene expression (AhR-CALUX) by hydrophobic compounds such as dioxins and dioxin-like molecules. Compound numbers, concentrations, their mass fluxes, and associated effect fluxes increased substantially during the storm event. Micropollutants detected in water and on SPM pointed toward inputs from combined sewer overflow (e.g., caffeine, paracetamol), urban runoff (e.g., mecoprop, terbutryn), and agricultural areas (e.g., azoxystrobin, bentazone). Particle-facilitated transport of triphenylphosphate and tris(1-chloro-2-propyl) phosphate accounted for up to 34 and 33% of the total mass flux even though SPM concentrations were &lt;1 g L–1. Effect fluxes attributed to SPM were similar or higher than in the water phase. The important role of SPM-bound transport emphasizes the need to consider not only concentrations but also mass and effect fluxes for surface water quality assessment and wastewater/stormwater treatment options. Environ Toxicol Chem 2021;40:88–99. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
Beneficial effects of Vigna angularis extract in osteoporosis and osteoarthritis
Authors: Lim Hyung Jin , Park Sang‐Ik , Bak Seon Gyeong , Cheong Sun Hee , Lee Soyoung , Baek Young‐Bin , Lee Chang‐Min , Lee Kang Min , Lee Seung Woong , Lee Seung‐Jae , Rho Mun‐Chual 
Published: October 2020

AbstractIn Asia, Vigna angularis (azuki bean) has been used as a traditional medicine to treat various diseases because of its biological properties. Osteoarthritis (OA) and osteoporosis (OP) are common regenerative bone diseases that are characterized by deterioration of joint and bone structure. In this study, we evaluated the effects of Vigna angularis extract (VAE) on monosodium iodoacetate (MIA)‐induced OA and ovariectomy (OVX)‐induced OP models. In the MIA‐induced OA results, severe OA was alleviated by the administration of VAE. Extensive local damage in the cartilage and hemorrhagic and edematous of surrounding tissues were decreased by VAE treatment. Articular cartilage was almost intact except for a focal mild abrasion, and the surface was glistening, similar to that of the normal joint. In the OVX‐induced OP results, bone mineral content (BMC) and bone mineral density (BMD) were recovered by VAE treatment, and it improved the microstructures of bone. These results show that VAE could inhibit OA and OP symptoms.
Rare and novel RUNX1 fusions in myeloid neoplasms: A single‐institute experience
Authors: Aypar Umut , Yao Jinjuan , Londono Dory M. , Khoobyar Rose , Scalise Angela , Arcila Maria E. , Roshal Mikhail , Xiao Wenbin , Zhang Yanming 
Published: October 2020

AbstractChromosome translocations involving the RUNX1 gene at 21q22 are recurring abnormalities in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), that is, t(8;21) and t(3;21) and in B‐cell acute lymphoblastic leukemia with t(12;21). These translocations result in the fusion of RUNX1 with RUNX1T1, MECOM, and ETV6, respectively, and are implicated in leukemogenesis. Here we describe 10 rare RUNX1 fusion gene partners, including six novel fusions, in myeloid neoplasia. Comprehensive molecular testing revealed the partner genes and features of these fusions in all the tested patients, and detected various recurring myeloid related gene mutations in eight patients. In two patients, RUNX1 mutations were identified. Most of these fusions were detected in patients with high‐grade MDS and AML with a relatively short survival. Integration of conventional chromosome analysis, FISH testing and molecular genetic studies allow a comprehensive characterization of these rare RUNX1 fusions. Our study may help define myeloid neoplasms with rare and novel RUNX1 translocations and support appropriate patient management.
JuSpace: A tool for spatial correlation analyses of magnetic resonance imaging data with nuclear imaging derived neurotransmitter maps
Authors: Dukart Juergen , Holiga Stefan , Rullmann Michael , Lanzenberger Rupert , Hawkins Peter C. T. , Mehta Mitul A. , Hesse Swen , Barthel Henryk , Sabri Osama , Jech Robert , Eickhoff Simon B. 
Published: October 2020

AbstractRecent studies have shown that drug‐induced spatial alteration patterns in resting state functional activity as measured using magnetic resonance imaging (rsfMRI) are associated with the distribution of specific receptor systems targeted by respective compounds. Based on this approach, we introduce a toolbox (JuSpace) allowing for cross‐modal correlation of MRI‐based measures with nuclear imaging derived estimates covering various neurotransmitter systems including dopaminergic, serotonergic, noradrenergic, and GABAergic (gamma‐aminobutric acid) neurotransmission. We apply JuSpace to two datasets covering Parkinson's disease patients (PD) and risperidone‐induced changes in rsfMRI and cerebral blood flow (CBF). Consistently with the predominant neurodegeneration of dopaminergic and serotonergic system in PD, we find significant spatial associations between rsfMRI activity alterations in PD and dopaminergic (D2) and serotonergic systems (5‐HT1b). Risperidone induced CBF alterations were correlated with its main targets in serotonergic and dopaminergic systems. JuSpace provides a biologically meaningful framework for linking neuroimaging to underlying neurotransmitter information.
A numerical study of magneto‐double‐diffusive‐convection of Casson fluid over a vertical cone under nonuniform heating at surface of cone
Authors: Rajora Richa , Kumar Anand 
Published: October 2020

AbstractThe objective of this investigation is to determine the impact of nonuniform heating on the transient natural convection of Casson fluid past a vertical cone in the appearance of a constant magnetic field. The overall analysis has executed in the presence of viscous dissipation, chemically reactive species, and ramped concentration. The derived governing partial differential equations in the dimensionless form are evaluated numerically using the implicit Crank‐Nicolson technique of finite difference method. The obtained numerical solutions for various physical parameters on all examined profiles have been shown graphically. The major result is found that the temperature and velocity profiles have a maximum magnitude at the middle of the lateral side of the cone. Also, the concentration profile has a maximum magnitude at for ramped concentration case.
Economic fitness: How equity market returns reflect the realization of economic growth potential
Authors: Chu Ted H. , Stocker Marshall L. , Tan Brandon J. 
Published: October 2020

AbstractThe relative complexity of a country's economy explains relative per capita wealth. Measures of complexity have also been used to improve the estimation accuracy of gross domestic product (GDP) growth forecasts. Why complexity matters is settled in the theory of gains from trade. Not settled are the determinants of complexity and how complexity can be unleashed to facilitate economic growth. We explore how economic institutions, as measured by an index of economic freedom, and economic complexity interact and impact a country's equity market return. We find complex economies where realized per capita GDP is lower than comparably complex economies experience an acceleration in GDP growth when economic freedom is increased. Simultaneous to the gains in economic institutions and complexity, equity markets outperform, suggesting the wealth of a nation rests on the institutions that facilitate complexity.
Respiratory effects induced by occupational exposure to refractory ceramic fibers
Authors: Gu Yishuo , He Wei , Wang Yanhua , Chen Juan , Wang Hongfei , Gao Panjun , Yang Siwen , Zhu Xiaojun , Ma Wenjun , Li Tao 
Published: October 2020

AbstractRefractory ceramic fibers (RCFs) are increasingly used as heating‐insulated materials in various industries. However, toxicological and epidemiological studies focusing on the adverse effects of RCFs were still insufficient, particularly in China. We conducted a cross‐sectional study to evaluate comprehensively the associations between occupational exposure to RCFs and respiratory health effects among Chinese workers. We measured and calculated cumulative RCFexposure levels of RCFs workers from the biggest RCFs factory in China. In total, 430 RCF‐exposed workers and 121 controls were enrolled in this study. Physical examinations of the respiratory system were performed and serum levels of biomarkers including Clara cell protein 16 (CC16), surfactant protein D (SP‐D), transforming growth factor β1 (TGF‐β1), and 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) were determined among all subjects. RCF exposure workers showed a higher prevalence rate of respiratory symptoms (cough: 11.9%) and lower levels of small airways function indices (V50%: 82.71 ± 20.01, maximal mid expiratory flow (MMEF)%: 81.08 ± 19.56) compared with the control group (cough: 5.0%, V50%: 90.64 ± 24.36, MMEF%: 88.83 ± 24.22). RCFs workers showed higher levels of TGF‐β1 (31.04 ng/mL) and 8‐OHdG (130.72 ng/mL) and lower levels of CC16 (3.68 ng/mL) compared with the controls (TGF‐β1: 26.63 ng/mL, 8‐OHdG: 106.86 ng/mL, CC16: 5.65 ng/mL). After adjusting for covariates, cumulative RCF exposure levels showed significant positive associations with the levels of TGF‐β1 and 8‐OHdG and negative association with the level of CC16. Occupational RCF exposure could induce adverse respiratory health effects, including cough and small airways damage, which may correlate to the altered levels of lung damage markers (CC16 and TGF‐β1) and oxidative markers (8‐OHdG).