bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation vs. Understanding: A Tension, in Quantum Chemistry and Beyond. Part A. Stage Setting
Authors: Hoffmann Roald , Malrieu Jean‐Paul 
Published: November 2019

AbstractWe begin our tripartite Essay with a triangle of understanding, theory and simulation. Sketching the intimate tie between explanation and teaching, we also point to the emotional impact of understanding. As we trace the development of theory in chemistry, Dirac's characterization of what is known and what is needed for theoretical chemistry comes up, as does the role of prediction, and Thom's phrase “To predict is not to explain.” We give a typology of models, and then describe, no doubt inadequately, machine learning and neural networks. In the second part, we leave philosophy, beginning by describing Roald's being beaten by simulation. This leads us to artificial intelligence (AI), Searle's Chinese room, and Strevens’ account of what a go‐playing program knows. Back to our terrain—we ask “Quantum Chemistry, † ca. 2020?” Then move to examples of AI affecting social matters, ranging from trivial to scary. We argue that moral decisions are hardly to be left to a computer. At this point, we try to pull the reader up, giving the opposing view of an optimistic, limitless future a voice. But we don't do justice to that view—how could we? We return to questioning the ascetic dimension of scientists, their romance with black boxes. Onward: In the 3rd part of this Essay, we work our way up from pessimism. We trace (another triangle!) the special interests of experimentalists, who want the theory we love, and reliable numbers as well. We detail in our own science instances where theory gave us real joy. Two more examples‐on magnetic coupling in inorganic diradicals, and the way to think about alkali metal halides, show us the way to integrate simulation with theory. Back and forth is how it should be—between painfully‐obtained, intriguing numbers, begging for interpretation, in turn requiring new concepts, new models, new theoretically grounded tools of computation. Through such iterations understanding is formed. As our tripartite Essay ends, we outline a future of consilience, with a role both for fact‐seekers, and searchers for understanding. Chemistry's streak of creation provides in that conjoined future a passage to art and to perceiving, as we argue we must, the sacred in science.
Identification of Catalytic Sites for Oxygen Reduction in Metal/Nitrogen‐Doped Carbons with Encapsulated Metal Nanoparticles
Authors: Chen Ming‐Xi , Zhu Mengzhao , Zuo Ming , Chu Sheng‐Qi , Zhang Jing , Wu Yuen , Liang Hai‐Wei , Feng Xinliang 
Published: November 2019

AbstractThe development of metal‐N‐C materials as efficient non‐precious metal (NPM) catalysts for catalysing the oxygen reduction reaction (ORR) as alternatives to platinum is important for the practical use of proton exchange membrane fuel cells (PEMFCs). However, metal‐N‐C materials have high structural heterogeneity. As a result of their high‐temperature synthesis they often consist of metal‐Nx sites and graphene‐encapsulated metal nanoparticles. Thus it is hard to identify the active structure of metal‐N‐C catalysts. Herein, we report a low‐temperature NH4Cl‐treatment to etch out graphene‐encapsulated nanoparticles from metal‐N‐C catalysts without destruction of co‐existing atomically dispersed metal‐Nx sites. Catalytic activity is much enhanced by this selective removal of metallic nanoparticles. Accordingly, we can confirm the spectator role of graphene‐encapsulated nanoparticles and the pivotal role of metal‐Nx sites in the metal‐N‐C materials for ORR in the acidic medium.
Controlled Synthesis of a Vacancy‐Defect Single‐Atom Catalyst for Boosting CO2 Electroreduction
Authors: Rong Xin , Wang Hong‐Juan , Lu Xiu‐Li , Si Rui , Lu Tong‐Bu 
Published: November 2019

AbstractThe reaction of precursors containing both nitrogen and oxygen atoms with NiII under 500 °C can generate a N/O mixing coordinated Ni‐N3O single‐atom catalyst (SAC) in which the oxygen atom can be gradually removed under high temperature due to the weaker Ni−O interaction, resulting in a vacancy‐defect Ni‐N3‐V SAC at Ni site under 800 °C. For the reaction of NiII with the precursor simply containing nitrogen atoms, only a no‐vacancy‐defect Ni‐N4 SAC was obtained. Experimental and DFT calculations reveal that the presence of a vacancy‐defect in Ni‐N3‐V SAC can dramatically boost the electrocatalytic activity for CO2 reduction, with extremely high CO2 reduction current density of 65 mA cm−2 and high Faradaic efficiency over 90 % at −0.9 V vs. RHE, as well as a record high turnover frequency of 1.35×105 h−1, much higher than those of Ni‐N4 SAC, and being one of the best reported electrocatalysts for CO2‐to‐CO conversion to date.
3D Electron Diffraction Unravels the New Zeolite ECNU‐23 from the “Pure” Powder Sample of ECNU‐21
Authors: Liu Xue , Luo Yi , Mao Wenting , Jiang Jingang , Xu Hao , Han Lu , Sun Junliang , Wu Peng 
Published: November 2019

AbstractA novel crystalline high‐silica zeolite with 12×8‐membered ring (R) channel system is prepared with the aid of the 3D electron diffraction (3D ED) technique. A crystal with the same topology as one of the predicted daughter structures of CIT‐13 germanosilicate, named ECNU‐23 (East China Normal University 23) was coincidentally detected by the 3D ED investigation during the structure characterization of the “pure” powder sample of existing one‐dimension (1D) 10‐R ECNU‐21. By controlling the alkaline‐assisted hydrolysis under moderate conditions, we purified the phase of ECNU‐23 by selectively breaking and removing the chemically weak Ge(Si)‐O‐Ge and metastable Si‐O‐Si bonds. Its structure was determined based on the 3D ED data, and confirmed by high‐resolution TEM images and powder X‐ray diffraction (PXRD) data. The aluminosilicate Al‐ECNU‐23 shows unique catalytic properties in the isomerization/ disproportionation of m‐xylene as solid‐acid catalyst.
Simulation vs. Understanding: A Tension, in Quantum Chemistry and Beyond. Part B. The March of Simulation, for Better or Worse
Authors: Hoffmann Roald , Malrieu Jean‐Paul 
Published: November 2019

AbstractIn the second part of this Essay, we leave philosophy, and begin by describing Roald's being trashed by simulation. This leads us to a general sketch of artificial intelligence (AI), Searle's Chinese room, and Strevens’ account of what a go‐playing program knows. Back to our terrain—we ask “Quantum Chemistry, † ca. 2020?” Then we move to examples of Big Data, machine learning and neural networks in action, first in chemistry and then affecting social matters, trivial to scary. We argue that moral decisions are hardly to be left to a computer. And that posited causes, even if recognized as provisional, represent a much deeper level of understanding than correlations. At this point, we try to pull the reader up, giving voice to the opposing view of an optimistic, limitless future. But we don't do justice to that view—how could we, older mammals on the way to extinction that we are? We try. But then we return to fuss, questioning the ascetic dimension of scientists, their romance with black boxes. And argue for a science of many tongues.
Atypical Hybrid Metal–Organic Frameworks (MOFs): A Combinative Process for MOF‐on‐MOF Growth, Etching, and Structure Transformation
Authors: Lee Sujeong , Oh Sojin , Oh Moonhyun 
Published: November 2019

AbstractThe structural, compositional, and morphological features of metal–organic frameworks (MOFs) govern their properties and applications. Construction of hybrid MOFs with complicated structures, components, or morphologies is significant for the development of well‐organized MOFs. An advanced route is reported for construction of atypical hybrid MOFs with unique morphologies and complicated components: 1) MOF‐on‐MOF growth of a 3D zeolitic imidazolate framework (ZIF) on a ZIF‐L template, 2) etching of a part of the 2D ZIF‐L template, and 3) structural transformation of 2D ZIF‐L into 3D ZIF. The formation of core–shell‐type MOF rings and plates is controlled by regulating the three processes. The formation route for the core–shell‐type MOF rings and plates was monitored by tracking changes in morphology, structure, and composition. Carbon materials prepared from the pyrolysis of the core–shell‐type hybrid MOFs displayed enhanced oxygen reduction reaction activities compared to their monomeric counterparts.
Novel anion exchange membrane with low ionic resistance based on chloromethylated/quaternized‐grafted polystyrene for energy efficient electromembrane processes
Authors: Golubenko Daniel V. , Van der Bruggen Bart , Yaroslavtsev Andrey B. 
Published: November 2019

ABSTRACTA novel anion‐exchange membrane has been manufactured by chloromethylation and subsequent quaternization of polystyrene within a graft copolymer films based on UV‐oxidized polymethylpentene. Particular attention is given to the kinetics of chloromethylation and the influence of the reaction conditions on the properties of the anion‐exchange membranes. By means of variation of the polystyrene content and its crosslinking degree we have obtained membranes that have an ion‐exchange capacity from 1.1 to 2.9 mmole g−1, anion transport numbers between 91.0 and 95.5% and specific ionic conductivities ( ranging from 2 to 25 mS cm−1. The developed membranes due to their low thickness and high conductivities have a remarkably low surface ionic resistance of around 0.6 Ω cm2. It was calculated that the use of the developed materials will increase the efficiency of reverse electrodialysis energy production by 8–10% compared to the state of the art membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48656.
Low expression of long noncoding RNA CTC‐297N7.9 predicts poor prognosis in patients with hepatocellular carcinoma
Authors: Zhu Sicong , Huang Xuelian , Zhang Kelin , Tan Wenliang , Lin Zhirong , He Qing , Chen Yajin , Shang Changzhen 
Published: November 2019

AbstractBackgroundLong noncoding RNAs (lncRNAs) are reported to play important roles in tumorigenesis of various malignant tumors. However, the clinical significance of aberrant lncRNA expression in hepatocellular carcinoma (HCC) is still elusive.MethodsFirstly, a differentially expressed lncRNA CTC‐297N7.9 in HCC was detected by analyzing the data from The Cancer Genome Atlas (TCGA). Secondly, the expression level of CTC‐297N7.9 was examined in four HCC cell lines and 60 pairs of HCC tissues by polymerase chain reaction (PCR) assay at our center. Thirdly, receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic value of CTC‐297N7.9 for HCC. Correlation and survival analysis of HCC patients from the TCGA and our center were also carried out to assess the predictive value of CTC‐297N7.9. Finally, survival prognostic models were established combining lncRNA expression and other clinical parameters.ResultsThe expression of CTC‐297N7.9 was downregulated in HCC cell lines and HCC tissues. ROC curve revealed its significant diagnostic value in HCC. CTC‐297N7.9 expression correlated with serum alpha‐fetal protein (AFP), tumor stage, and tumor differentiation. Survival analysis indicated that overall survival (OS) and disease‐free survival (DFS) are all positively associated with CTC‐297N7.9 expression, especially in patients without viral hepatitis or cirrhosis. Cox regression analysis showed that CTC‐297N7.9 expression level is an independent prognostic factor for both OS and DFS in HCC patients. Based on the model, CTC‐297N7.9 was observed to be negatively correlated to risk score, indicating its role as a protective factor for HCC.ConclusionOur study demonstrated that the low expression of CTC‐297N7.9 is associated with poor prognosis in HCC patients, suggesting its possible role as a potential prognostic marker for HCC.
Photoimmunotherapy targeting biliary‐pancreatic cancer with humanized anti‐TROP2 antibody
Authors: Nishimura Takashi , Mitsunaga Makoto , Sawada Ryoichi , Saruta Masayuki , Kobayashi Hisataka , Matsumoto Noriko , Kanke Toru , Yanai Hiroyuki , Nakamura Koji 
Published: November 2019

AbstractPhotoimmunotherapy (PIT) is a new type of tumor‐specific treatment utilizing monoclonal antibody (mAb)‐photosensitizer conjugates and near‐infrared (NIR) light irradiation. One potential PIT target, the type I transmembrane protein TROP2, is expressed at high levels in many cancers, including pancreatic carcinoma (PC) and cholangiocarcinoma (CC), in which its expression is correlated with poor prognosis and tumor aggressiveness. In this study, we assessed the efficacy of PIT utilizing newly developed humanized anti‐TROP2 mAb conjugated to the photosensitizer IR700 (TROP2‐IR700) for PC and CC. Immunohistochemistry on PC and CC tissue microarrays confirmed that TROP2 is overexpressed in about half of PC and CC specimens. Using cultured PC and CC cells, TROP2‐IR700 localized TROP2‐specific and target‐specific cell killing was observed after NIR light irradiation. In addition, TROP2‐IR700 was localized to mouse xenograft tumors expressing TROP2 after intravenous injection. PC and CC xenograft tumor growth was significantly inhibited by TROP2‐targeted PIT relative to controls. The efficacy of TROP2‐targeted PIT in vitro and against xenografted tumors in vivo suggests promise as a therapy for human PC and CC, both of which currently have dismal prognoses and limited therapeutic options.
Using a PCR‐Based Method To Analyze and Model Large, Heterogeneous Populations of DNA
Authors: Andrade Helena , Thomas Alvin K. , Lin Weilin , Reddavide Francesco V. , Zhang Yixin 
Published: November 2019

AbstractThe study of populations of large size and high diversity is limited by the capability of collecting data. Moreover, for a pool of individuals, each associated with a unique characteristic feature, as the pool size grows, the possible interactions increase exponentially and quickly go beyond the limit of computation and experimental studies. Herein, the design of DNA libraries with various diversity is reported. By using a facile analytical method based on real‐time PCR, the diversity of a pool of DNA can be evaluated to allow extraordinarily high heterogenicity (e.g., >1 trillion). It is demonstrated that these DNA libraries can be used to model heterogeneous populations; these libraries exhibit functions such as self‐protection, suitability for biased expansion, and the possibility to evolve into amorphous structures. The method has shown the remarkable power of parallel computing with DNA, since it can resemble an analogue computer and be applied in selection‐based biotechnology methods, such as DNA‐encoded chemical libraries. As a chemical approach to solve problems traditionally for genetic and statistical analysis, the method provides a quick and cost‐efficient evaluation of library diversity for intermediate steps through a selection process.
Natural Deep Eutectic Solvents as Performance Additives for Peroxygenase Catalysis
Authors: Ma Yunjian , Li Yongru , Ali Shahid , Li Peilin , Zhang Wuyuan , Rauch Marine C. R. , Willot Sébastien J.‐P. , Ribitsch Doris , Choi Young Hae , Alcalde Miguel , Hollmann Frank , Wang Yonghua 
Published: November 2019

AbstractNatural deep eutectic solvents (NADES) are proposed as alternative solvents for peroxygenase‐catalysed oxyfunctionalization reactions. Choline chloride‐based NADES are of particular interest as they can serve as solvent, enzyme‐stabiliser and sacrificial electron donor for the in situ H2O2 generation. This report provides the first proof‐of‐concept and basic characterisation of this new reaction system. Highly promising turnover numbers for the biocatalysts of up to 200,000 have been achieved.
Design and Analysis of the 4‐Anilinoquin(az)oline Kinase Inhibition Profiles of GAK/SLK/STK10 Using Quantitative Structure‐Activity Relationships
Authors: Asquith Christopher R. M. , Laitinen Tuomo , Bennett James M. , Wells Carrow I. , Elkins Jonathan M. , Zuercher William J. , Tizzard Graham J. , Poso Antti 
Published: November 2019

AbstractThe 4‐anilinoquinoline and 4‐anilinoquinazoline ring systems have been the focus of significant efforts in prior kinase drug discovery programs, which have led to approved medicines. Broad kinome profiles of these compounds have now been assessed with the advent of advanced screening technologies. These ring systems, while originally designed for specific targets including epidermal growth factor receptor (EGFR), but actually display a number of potent collateral kinase targets, some of which have been associated with negative clinical outcomes. We have designed and synthesized a series of 4‐anilinoquin(az)olines in order to better understand the structure‐activity relationships of three main collateral kinase targets of quin(az)oline‐based kinase inhibitors: cyclin G associated kinase (GAK), STE20‐like serine/threonine‐protein kinase (SLK) and serine/threonine‐protein kinase 10 (STK10). This was achieved through a series of quantitative structure‐activity relationship (QSAR) analysis, water mapping of the kinase ATP binding sites and extensive small‐molecule X‐ray structural analysis.
Synthesis of Combretastatin‐A4 Carboxamidest that Mimic Sulfonyl Piperazines by a Molecular Hybridization Approach: in vitro Cytotoxicity Evaluation and Inhibition of Tubulin Polymerization
Authors: Jadala Chetna , Sathish Manda , Anchi Pratibha , Tokala Ramya , Lakshmi Uppu Jaya , Reddy Velma Ganga , Shankaraiah Nagula , Godugu Chandraiah , Kamal Ahmed 
Published: November 2019

AbstractMolecular hybridization approach is a promising structural modification tool to design new chemical entities (NCEs) by mimicking two different pharmacophoric units into one scaffold to enhance the biological properties. With this aim, combretastatin‐A4 acids were integrated with sulfonyl piperazine scaffolds as a one molecular platform and evaluated for their in vitro antiproliferative activity against a panel of human cancer lines cell lines namely, lung (A549), mouse melanoma (B16F10), breast (MDA MB‐231and MCF‐7) and colon (HCT‐15) by MTT assay. Amongst which the compound (E)‐3‐(4‐Chlorophenyl)‐1‐(4‐((4‐chlorophenyl)sulfonyl)piperazin‐1‐yl)‐2‐(3,4,5‐trimethoxyphenyl)prop‐2‐en‐1‐one (5 ab) displayed significant IC50 values in the range of 0.36 to 7.08 μm against the selected cancer cell lines. Moreover, 5 ab was found to be the most potent member of this series with IC50 0.36±0.02 μm. Further investigations revealed that the compound 5 ab displayed significant inhibition of tubulin assembly with IC50 5.24±0.06 μm and molecular docking studies also disclosed the binding of 5 ab effectively in CA4 binding space at the colchicine binding site. The flow cytometric analysis demonstrated that the compound 5 ab caused cell cycle arrest at G2/M phase in A549 cells. Compound 5 ab induced apoptosis in A549 cells which was further evaluated by different staining assays such as DAPI and AO which undoubtedly speculated, the induction of apoptosis. To study the anti‐migration with 5 ab, cell migration/scratch wound assay was performed and the extent of apoptosis was studied by Annexin‐V, including mitochondrial potential by JC‐1 staining.
Physiological assessment of high glucose neurotoxicity in mouse and rat retinal explants
Authors: Calbiague Víctor M. , Vielma Alex H. , Cadiz Bárbara , Paquet‐Durand Francois , Schmachtenberg Oliver 
Published: November 2019

AbstractOne of the tissues of the central nervous system most affected by diabetes is the retina. Despite a growing understanding of the biochemical processes involved in glucose toxicity, little is known about the physiological consequences of chronic high glucose (HG) on individual neurons and neuronal circuits. Electroretinogram recordings suggest that retinal bipolar cells (BCs), which filter and transmit photoreceptor output to the inner retina, are among the first cells affected by diabetic conditions, and may therefore serve as sensitive early biomarkers for incipient neuronal damage caused in diabetes. Here, we comparatively assessed retinal integrity, calcium responses, and the electrophysiological profiles of specific BC types of mouse and rat organotypic retinal explants after 1 to 3 weeks in tissue culture, under moderate glucose (MG) and HG conditions. While the retinal layers of both rodent species displayed a progressively reduced thickness in culture, BCs retained their electrophysiological profiles and remained morphologically identifiable for up to 2 weeks. Responses to glutamate and endogenous inhibitory responses were routinely observed, indicating that the retinal circuitry remained intact during this period. Significant physiological differences between MG and HG conditions were evident in calcium signals and in the time course of responses to glutamate, but the voltage‐gated current profiles of BCs displayed only minor variations. Overall, rat retina appeared slightly more sensitive to HG levels compared with mouse. In conclusion, electrophysiological analysis of neuronal function in rodent retinal explants is useful for the study of early damage due to HG neurotoxicity.
Unsaturation‐Dependent Nanostructures Self‐Assembled from Oligopeptide Amphiphiles Capable of Generating Singlet Oxygen
Authors: Feng Jia‐Ru , Qin Si‐Yong , Rong Lei , Cheng Yin‐Jia , Ma Yi‐Han , Zhang Ai‐Qing 
Published: November 2019

AbstractWe report here on three oligopeptide amphiphiles (OPA1‐3) with different unsaturated double bonds, which self‐assemble into shape‐specific nanostructures. It was found that OPA1 with saturated hydrophobic tail self‐assembled into conventional cylindrical nanofibers, while the unsaturated OPA2‐3 molecules self‐organized into helical nanoarchitectures. Due to the different double bond numbers in hydrophobic tails of OPA2‐3, the helical pitch and width of their self‐assemblies varied. Specially, linoleic acid‐bearing OPA3 could be oxidized by lipoxidase to create hydroperoxide‐containing OPA4, which further generated singlet oxygen (1O2) in the presence of catalytic iron (II) ion. The established system may provide a self‐deliverable nanoplatform for 1O2‐mediated cancer treatment.
Alkali and Alkaline‐Earth Cations in Complexes with Small Bioorganic Ligands: Ab Initio Benchmark Calculations and Bond Energy Decomposition
Authors: López Roberto , Díaz Natalia , Suárez Dimas 
Published: November 2019

AbstractHerein, we report a computational database for the complexes of alkali [Li(I), Na(I), K(I)] and alkaline‐earth [Be(II), Mg(II) and Ca(II)] cations with 25 small ligands with varying charge and donor atoms (“O”, “N”, and “S”) that provides geometries and accurate bond energies useful to analyze metal‐ligand interactions in proteins and nucleic acids. The role of the ligand→metal charge transfer, the equilibrium bond distance, the electronegativity of the donor atom, the ligand polarizability, and the relative stability of the complexes are discussed in detail. The interacting quantum atoms (IQA) method is used to decompose the binding energy into electrostatic and quantum mechanical contributions. In addition, bond energies are also estimated by means of multipolar electrostatic calculations. No simple correlation exists between bond energies and structural/electronic descriptors unless the data are segregated by the type of ligand or metal. The electrostatic attraction of some molecules (H2O, NH3, CH3OH) towards the metal cations is well reproduced using their (unrelaxed) atomic multipoles, but the same comparison is much less satisfactory for other ligands (e. g. benzene, thiol/thiolate groups, etc.). Besides providing reference structures and bond energies, the database can contribute to validate molecular mechanics potentials capable of yielding a balanced description of alkali and alkaline‐earth metals binding to biomolecules.