bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibitor‐Induced Dimerization of an Essential Oxidoreductase from African Trypanosomes
Authors: Wagner Annika , Le Thien Anh , Brennich Martha , Klein Philipp , Bader Nicole , Diehl Erika , Paszek Daniel , Weickhmann A. Katharina , Dirdjaja Natalie , Krauth‐Siegel R. Luise , Engels Bernd , Opatz Till , Schindelin Hermann , Hellmich Ute A. 
Published: January 2019

AbstractTrypanosomal and leishmanial infections claim tens of thousands of lives each year. The metabolism of these unicellular eukaryotic parasites differs from the human host and their enzymes thus constitute promising drug targets. Tryparedoxin (Tpx) from Trypanosoma brucei is the essential oxidoreductase in the parasite's hydroperoxide‐clearance cascade. In vitro and in vivo functional assays show that a small, selective inhibitor efficiently inhibits Tpx. With X‐ray crystallography, SAXS, analytical SEC, SEC‐MALS, MD simulations, ITC, and NMR spectroscopy, we show how covalent binding of this monofunctional inhibitor leads to Tpx dimerization. Intra‐ and intermolecular inhibitor–inhibitor, protein–protein, and inhibitor–protein interactions stabilize the dimer. The behavior of this efficient antitrypanosomal molecule thus constitutes an exquisite example of chemically induced dimerization with a small, monovalent ligand that can be exploited for future drug design.
Facile Access to an NHC‐Coordinated Silicon Ring Compound with a Si=N Group and a Two‐Coordinate Silicon Atom
Authors: Keuter Jan , Hepp Alexander , Mück‐Lichtenfeld Christian , Lips Felicitas 
Published: January 2019

AbstractReaction of the bicyclo[1.1.0]tetrasilatetraamide Si4{N(SiMe3)Dipp}4 1 (Dipp=2,6‐diisopropylphenyl) with 5 equiv of the N‐heterocyclic carbene NHCMe4 (1,3,4,5‐tetramethylimidazol‐2‐ylidene) affords a bifunctional carbene‐coordinated four‐membered‐ring compound with a Si=N group and a two‐coordinate silicon atom Si4{N(SiMe3)Dipp}2(NHCMe4)2(NDipp) 2. When 2 reacts with 0.25 equiv sulfur (S8), two sulfur atoms add to the divalent silicon atom in plane and perpendicular to the plane of the Si4 ring, which confirms the silylone character of the two‐coordinate silicon atom in 2.
Enhanced breakdown strength and electrical tree resistance properties of MMT/SiO2/LDPE multielement composites
Authors: Zhang Xiaohong , Shi Zexiang , Ma Lisha , Gao Junguo , Guo Ning 
Published: January 2019

ABSTRACTMontmorillonite (MMT)/low‐density polyethylene (LDPE) nanocomposites have excellent partial discharge resistance and electrical tree resistance compared with pure LDPE. However, the MMT/LDPE nanocomposites have low breakdown strength due to the poor compatibility between nano‐MMT and LDPE. In order to improve the breakdown strength of the MMT/LDPE composites without changing the LDPE matrix, an MMT/SiO2/LDPE multielement composite was prepared by melt blending, and its breakdown strength and electrical tree resistance properties were investigated. The results show that the MMT/SiO2/LDPE multielement composite has excellent breakdown strength and electrical tree resistance properties compared with the MMT/LDPE composite. The reasons for the excellent insulation properties of the MMT/SiO2/LDPE multielement composites were analyzed by exploring the effects of MMT and SiO2 on the microstructure and trap characteristics of LDPE. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47364.
Tuning the interphase adhesion in high‐density polyethylene–silica nanocomposites with ionic liquids
Authors: Donato Katarzyna Z. , Donato Ricardo K. , Zhigunov Alexander , Mauler Raquel S. , Schrekker Henri S. 
Published: January 2019

ABSTRACTThis work addresses the use of ionic liquids (ILs) as multifunctional additives in the formation of high‐density polyethylene (HDPE)/sol–gel silica nanocomposites via the melt‐mixing process. Different approaches for nanocomposite formation were studied and compared, including (1) silica modification with ILs during the sol–gel process and further addition into the polymer matrix, (2) reactive mixing in which silica‐IL filler was formed in situ, and (3) direct IL application in the melt‐mixing chamber with nonmodified silica xerogel and HDPE. The nanocomposites were characterized by thermogravimetric analyses, differential scanning calorimetry, scanning electron microscopy, dynamic thermomechanical analyses, transmission electron microscopy, and contact angle analyses. To improve the silica compatibilization with HDPE, we investigated imidazolium ILs that presented at least one nonpolar ionic counterpart. This permitted control of the silica structure, morphology, dispersion, and interfacial interactions, providing enhancements in thermomechanical properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47366.
Doubly N‐Confused Calix[6]phyrin Bis‐Organopalladium Complexes: Photostable Triplet Sensitizers for Singlet Oxygen Generation
Authors: Pushpanandan Poornenth , Won Dong‐Hoon , Mori Shigeki , Yasutake Yuhsuke , Fukatsu Susumu , Ishida Masatoshi , Furuta Hiroyuki 
Published: January 2019

AbstractTriplet photosensitizers that generate singlet oxygen efficiently are attractive for applications such as photodynamic therapy (PDT). Extending the absorption band to a near‐infrared (NIR) region (700 nm≈) with reasonable photostability is one of the major demands in the rational design of such sensitizers. We herein prepared a series of mono‐ and bis‐palladium complexes (1‐Pd‐H2, 2‐Pd‐H2, 1‐Pd‐Pd, and 2‐Pd‐Pd) based on modified calix[6]phyrins as photosensitizers for singlet oxygen generation. These palladium complexes showed intense absorption profiles in the visible‐to‐NIR region (500–750 nm) depending on the number of central metals. Upon photoirradiation in the presence of 1,5‐dihydroxynaphthalene (DHN) as a substrate for reactive oxygen species, the bis‐palladium complexes generated singlet oxygen with high efficiency and excellent photostability. Singlet oxygen generation was confirmed from the characteristic spectral feature of the spin trapped complex in the EPR spectrum and the intact 1O2 emission at 1270 nm.
Polymorphic Pure Organic Luminogens with Through‐Space Conjugation and Persistent Room‐Temperature Phosphorescence
Authors: Zhang Tingting , Zhao Zihao , Ma Huili , Zhang Yongming , Yuan Wang Zhang 
Published: January 2019

AbstractPure organic luminogens with persistent room‐temperature phosphorescence (p‐RTP) have attracted increasing attention owing to their vital significance and potential applications in security inks, bioimaging, and photodynamic therapy. Previously reported p‐RTP luminogens normally possessed through‐bond conjugation. In this work, we report a pure organic luminogen, AN‐MA, the Diels–Alder cycloaddition adduct of anthracene (AN) and maleic anhydride (MA), which possesses isolated phenyl groups and an anhydride moiety. AN‐MA exhibits aggregation‐enhanced emission (AEE) characteristics with efficiency of approximately 2 % and up to 8.5 % in solution and crystals, respectively. Two polymorphs of AN‐MA were readily obtained that were able to generate UV emission from individual phenyl rings together with bright blue emission owing to the effective through‐space conjugation. Moreover, p‐RTP with a lifetime of up to approximately 1.6 s was obtained in the crystals. These results not only reveal a new system with both fluorescence and RTP dual emission but also suggest an alternative through‐space conjugation strategy towards pure organic p‐RTP luminogens with tunable emissions.
Beryllium Halide Complexes Incorporating Neutral or Anionic Ligands: Potential Precursors for Beryllium Chemistry
Authors: Paparo Albert , Jones Cameron 
Published: January 2019

AbstractReactions of the beryllium dihalide complexes [BeX2(OEt2)2] (X=Br or I) with N,N,N′,N′‐tetramethylethylenediamine (TMEDA), a series of diazabutadienes, or bis(diphenylphosphino)methylene (DPPM) have yielded the chelated complexes, [BeX2(TMEDA)], [BeX2{(RN=CH)2}] (R=tBu, mesityl (Mes), 2,6‐diethylphenyl (Dep) or 2,6‐diisopropylphenyl (Dip)), and the non‐chelated system, [BeI2(κ1‐P‐DPPM)2]. Reactions of lithium or potassium salts of a variety of β‐diketiminates have given both three‐coordinate complexes, [{HC(RCNAr)2}BeX] (R=H or Me; Ar=Mes, Dep or Dip; X=Br or I); and four‐coordinate systems, [{HC(MeCNPh)2}BeBr(OEt2)] and [{HC(MeCNDip)(MeCNC2H4NMe2}BeI]. Alkali metal salts of ketiminate, guanidinate, boryl/phosphinosilyl amide, or terphenyl ligands, lead to dimeric [{BeI{μ‐[(OCMe)(DipNCMe)]CH}}2], and monomeric [{iPr2NC(NMes)2}BeI(OEt2)], [κ2‐N,P‐{(HCNDip)2B}(PPh2SiMe2)NBeI(OEt2)] and [{C6H3Ph2‐2,6}BeBr(OEt2)], respectively. Compound [{HC(MeCNPh)2}BeBr(OEt2)] undergoes a Schlenk redistribution reaction in solution, affording the homoleptic complex, [{HC(MeCNPh)2}2Be]. The majority of the prepared complexes have been characterized by X‐ray crystallography and multi‐nuclear NMR spectroscopy. The structures and stability of the complexes are discussed, as is their potential for use as precursors in poorly developed low oxidation state beryllium chemistry.
Effect of Surface Chemical Bonding States on Lithium Intercalation Properties of Surface‐Modified Lithium Cobalt Oxide
Authors: Hata Jun‐Ichi , Hirayama Masaaki , Suzuki Kota , Dupré Nicolas , Guyomard Dominique , Kanno Ryoji 
Published: January 2019

AbstractUnderstanding interfacial reactions between surface‐modified lithium intercalation cathodes and organic electrolytes facilitates the design of highly functional cathodes for lithium‐ion batteries. Here, the chemical bonding state between a LiCoO2 cathode and a ZrO2−x surface layer is controlled by pulsed arc plasma deposition using different ion energies. The lithium intercalation properties and interfacial structure changes are subsequently analyzed. The Zr−O−Co‐modified surface formed by interaction between ZrO2−x and LiCoO2 provides superior cycle stability under high‐voltage operation (2.8–4.5 V). X‐ray photoemission spectroscopy clarifies that the Zr−O−Co surface forms highly adhesive ZrOxFy as a cathode electrolyte interphase (CEI). The chemical bonding state at the ZrO2−x/LiCoO2 interface affects the reactivity of ZrO2−x with electrolyte species as well as the architecture of the CEI, which may determine the cell performances of lithium intercalation cathodes.
Less willing to pay but more willing to buy: How the elicitation method impacts the valuation of a promotion
Authors: Lu Zoe Y. , Hsee Christopher K. 
Published: January 2019

AbstractWillingness to pay (WTP—how much one is willing to pay for something) and willingness to buy (WTB—whether one is willing to buy something at a given price) are two common methods to elicit valuations and normatively should yield the same valuation order between two options. However, this research finds that WTP and WTB can yield opposite valuation orders between the regular offer and the promotional offer of a product. Specifically, it demonstrate that, (a) if the valuation of a product is only elicited with WTP, consumers value the product less when it is offered with a price promotion than when it is not; (b) if the valuation of a product is only elicited with WTB, consumers value the product more when it is offered with a price promotion than when it is not; and (c) if the valuation of a product is first elicited with WTP and then elicited with WTB, consumers always value the product less when it is offered with a price promotion than when it is not. A value‐inference account is proposed for the above findings, according to which, consumers infer the value of a promoted product differently when the valuation is elicited only with WTP or only with WTB. Theoretically, this research extends prior literature on sales promotion, showing that the valuation of a promotion is subject to the elicitation method. Practically, this research suggests how to help consumers manage their purchase intentions for promoted products.
Chemical Composition and Antioxidant Activity of Tuber indicum from Different Geographical Regions of China
Authors: Li Jia‐Mei , Liang Han‐Qiao , Qiao Peng , Su Kai‐Mei , Liu Pei‐Gui , Guo Shun‐Xing , Chen Juan 
Published: January 2019

AbstractTuber indicum, an endemic truffle species in eastern Asian, is an edible mushroom that is both an important export and widely distributed across China. Many existing studies on truffles focus on analyzing their taxonomy, population genetics, volatile organic compounds and artificial cultivation of the truffles, while little information is available about their nutrient composition and pharmacological activity, especially the relationship between chemical composition in ascocarps and their geographic distributions. This study presents a comprehensive investigation of the chemical composition of T. indicum, including free sugars, fatty acids, organic acids, phenolic acids, flavonoids, and polysaccharides, and tracks the antioxidant activity of T. indicum ascocarps collected from five geographical regions of four provinces in P. R. China: Hebei, Tibet, Yunnan, and Liaoning province. Our results showed that T. indicum collected from Qujing, Yunnan province, possessed the highest amount of free sugars (23.67 mg/g dw), total flavonoids (2.31 mg/g dw), total phenolics (4.46 mg/g dw) and the highest DPPH and ABTS radical‐scavenging activities. The amount of water‐soluble polysaccharides was the highest (115.24 mg/g dw) in ascocarps from Tibet, the total organic acids was the highest (22.073 mg/g dw) in ascocarps from Gongshan, and polyunsaturated fatty acids were most abundant in those from Hebei province. This study reveals that the quantity of chemical compounds in T. indicum varies by geographical origin. Detecting differences in chemical composition may provide important data for understanding the relationship between environmental factors and truffle formation, as well as quality evaluation of the commercial species T. indicum throughout China.
Bioinspired Design of Lysolytic Triterpenoid–Peptide Conjugates that Kill African Trypanosomes
Authors: Leeder W.‐Matthias , Giehler Fabian , Joswig Juliane , Göringer H. Ulrich 
Published: January 2019

AbstractHumans have evolved a natural immunity against Trypanosoma brucei infections, which is executed by two serum (lipo)protein complexes known as trypanolytic factors (TLF). The active TLF ingredient is the primate‐specific apolipoprotein L1 (APOL1). The protein has a pore‐forming activity that kills parasites by lysosomal and mitochondrial membrane fenestration. Of the many trypanosome subspecies, only two are able to counteract the activity of APOL1; this illustrates its evolutionarily optimized design and trypanocidal potency. Herein, we ask whether a synthetic (syn) TLF can be synthesized by using the design principles of the natural TLF complexes but with different chemical building blocks. We demonstrate the stepwise development of triterpenoid–peptide conjugates, in which the triterpenoids act as a cell‐binding, uptake and lysosomal‐transport modules and the synthetic peptide GALA acts as a pH‐sensitive, pore‐forming lysolytic toxin. As designed, the conjugate kills infective‐stage African trypanosomes through lysosomal lysis thus demonstrating a proof‐of‐principle for the bioinspired, forward‐design of a synTLF.
Natural Voltage‐Gated Sodium Channel Ligands: Biosynthesis and Biology
Authors: Lukowski April L. , Narayan Alison R. H. 
Published: January 2019

AbstractNatural product biosynthetic pathways are composed of enzymes that use powerful chemistry to assemble complex molecules. Small molecule neurotoxins are examples of natural products with intricate scaffolds which often have high affinities for their biological targets. The focus of this Minireview is small molecule neurotoxins targeting voltage‐gated sodium channels (VGSCs) and the state of knowledge on their associated biosynthetic pathways. There are three small molecule neurotoxin receptor sites on VGSCs associated with three different classes of molecules: guanidinium toxins, alkaloid toxins, and ladder polyethers. Each of these types of toxins have unique structural features which are assembled by biosynthetic enzymes and the extent of information known about these enzymes varies among each class. The biosynthetic enzymes involved in the formation of these toxins have the potential to become useful tools in the efficient synthesis of VGSC probes.
Probing Colocalization of N‐Ras and K‐Ras4B Lipoproteins in Model Biomembranes
Authors: Li Lei , Dwivedi Mridula , Patra Satyajit , Erwin Nelli , Möbitz Simone , Winter Roland 
Published: January 2019

AbstractSignaling of N‐Ras and K‐Ras4B proteins depends strongly on their correct localization in the cell membrane. In vivo studies suggest that intermolecular interactions foster the self‐association of both N‐Ras and K‐Ras4B and the formation of nanoclusters in the cell membrane. As sites for effector binding, nanocluster formation is thought to be essential for effective signal transmission of both N‐Ras and K‐Ras4B. To shed more light on the spatial arrangement and mechanism underlying the proposed cross‐talk between spatially segregated Ras proteins, the simultaneous localization of N‐Ras and K‐Ras4B and their effect on the lateral organization of a heterogeneous model biomembrane has been studied by using AFM and FRET methodology. It is shown that, owing to the different natures of their membrane anchor systems, N‐Ras and K‐Ras4B not only avoid assembly in bulk solution and do not colocalize, but rather form individual nanoclusters that diffuse independently in the fluid membrane plane.
The Role of the Anode Material in Selective Penicillin G Oxidation in Urine
Authors: Cotillas Salvador , Lacasa Engracia , Herraiz Miguel , Sáez Cristina , Cañizares Pablo , Rodrigo Manuel A. 
Published: January 2019

AbstractIn this work, the removal of antibiotic penicillin G by electrolysis with boron doped diamond (BDD) and mixed metal oxide (MMO) anodes in urine media is evaluated. First, electrolysis in different water matrices (sulfate, chloride and urine) were carried out with diamond anodes to shed light on the contribution of mediated mechanisms. Results showed that penicillin G was completely removed by electrolysis for electric charges below 5 Ah dm−3, regardless of the water matrix and the current density applied (10‐100 mA cm−2). Then, the influence of the anode material was evaluated for the degradation of penicillin G in urine media. A complete removal of the antibiotic was attained, regardless of the tested anode material, although the BDD anode was found to be more efficient than MMO. Results also showed that, at the current charges in which the antibiotic is depleted, the removal of other organics was much lower and the formation of chlorates was negligible, especially operating at low current densities. Because of this selective oxidation of the pharmaceutical compound, electrolysis can be proposed to be used as a pre‐treatment technology for later and cheaper biological treatment.
Overview of Surrogate Modeling in Chemical Process Engineering
Authors: McBride Kevin , Sundmacher Kai 
Published: January 2019

AbstractThe ability to accurately model and simulate chemical processes has been paramount to the growing success and efficiency in process design and operation. These improvements usually come with increasing complexity of the underlying models leading to substantial computational effort in their use. It may also occur that the structure of the model is sometimes unknown making optimization and study difficult. To circumvent these issues, mathematically simpler models, commonly known as surrogate models, have been designed and used to successfully replace these complex, underlying models with much success. This technique has seen increasing use within the chemical process engineering field and this article summarizes some popular surrogates and their recent use in this area.
The Influence of the Amino Acid Side Chains on the Raman Optical Activity Spectra of Proteins
Authors: Mensch Carl , Johannessen Christian 
Published: January 2019

AbstractThe front cover artwork is provided by Dr. Carl Mensch and Prof. Christian Johannessen from the Molecular Spectroscopy group at the University of Antwerp and the Ghent Quantum Chemistry Group. The image shows the spectroscopic response to the conformational flexibility of protein side‐chains as probed by Raman optical activity. Read the full text of the Article at 10.1002/cphc.201800924.
Stock price prediction using k‐medoids clustering with indexing dynamic time warping
Authors: Nakagawa Kei , Imamura Mitsuyoshi , Yoshida Kenichi 
Published: January 2019

AbstractVarious methods to predict stock prices have been studied. In the field of empirical finance, feature values for prediction include “value” and “momentum”. In this research, we use the pattern of stock price fluctuations which has not been fully utilized in the financial market as the input feature of prediction. We extract the representative price fluctuation patterns with k‐Medoids Clustering with Indexing Dynamic Time Warping method. This method is k‐medoids clustering on dissimilarity matrix using IDTW which measures DTW distance between indexed time‐series. We can visualize and grasp a price fluctuation pattern effective for prediction with the proposed method. To demonstrate the advantages of the proposed method, we analyze its performance using TOPIX. Experimental results show that the proposed method is effective for predicting monthly stock price changes.
Prognostic and clinicopathological significance of Cks1 in cancer: Evidence from a meta‐analysis
Authors: Zhang Yi , Chen Yuting , You Fan , Li Wang , Lang Zhiquan , Zou Zhenhong 
Published: January 2019

AbstractBackgroundCyclin‐dependent kinase subunit 1 (Cks1), as a highly conserved regulatory protein, has pleiotropic roles in cell cycle progression. As research progresses, increasingly more statistics show that Cks1 may be involved in the occurrence, development, and prognosis of a variety of tumors but the conclusions remain controversial. In addition, there has been no meta‐analysis demonstrating the correlation between Cks1 and cancer. Therefore, this meta‐analysis was performed to determine the prognostic and clinicopathological significance of Cks1 in various cancers.MethodsSystematic computer literature retrieval was conducted on the Web of Science, Embase, PubMed, CNKI, and Wanfang databases. Stata SE12.0 software was used in the quantitative meta‐analysis. The hazard ratio (HR) and relative risk (RR) were pooled to assess the relationship between Cks1 expression and overall survival (OS), disease‐free survival (DFS), and clinicopathological parameters.ResultsNineteen studies were included, totaling 2,224 participants. High expression of Cks1 was significantly correlated with worse OS (HR, 2.62; 95% confidence interval [CI], 2.18–3.14; p < 0.001) and poorer DFS (HR, 2.73; 95% CI, 1.83–4.08;
p < 0.001). In addition, high expression of Cks1 was related to lymph node metastasis (RR, 1.59; 95% CI, 1.22–2.07;
p = 0.001) and advanced T stage (RR, 1.14; 95% CI, 1.04–1.25;
p = 0.005).ConclusionsHigh Cks1 expression predicted poorer prognosis and worse clinicopathological parameters in various cancers. Increased Cks1 could be a significant prognostic biomarker for poor survival in patients with various cancers.