bluuebunny/crossref_metadata_2025 huggingface dataset:
3D Printing of Amylopectin‐Based Natural Fiber Composites
Authors: Jiang Yijie , Raney Jordan R.
Published: September 2019

Many ancient Chinese structures, such as portions of the Great Wall, use a unique mortar that derives from glutinous rice (commonly called “sticky rice”). Unlike other types of rice, sticky rice is rich in amylopectin with negligible amylose. Inspired by the long‐term stability of the amylopectin‐based mortars in ancient structures, sticky rice (SR)‐based materials for 3D printing are developed. Heat causes amylopectin gelatinization, during which molecular branches open to form a large network of gel balls. This causes a merger of the granules and improved interaction between the matrix and fillers. To enhance the mechanical properties, cotton fibers are included, ≈11 µm in diameter. During amylopectin gelatinization, secondary fibers emerge from the primary fibers, creating a complex two‐level fiber network. Both the fibers and matrix constitute a 3D printable fiber composite consisting entirely of natural, inexpensive, and scalable components. The processing steps make no use of any non‐natural materials or hazardous chemicals. A systematic design of experiments is conducted to understand the effect of processing parameters on the mechanical properties. Scalability by printing low‐density cellular materials is demonstrated. Finally, it is shown that SR composites are more resilient than common thermoplastic composites when subjected to flame, heat, or ultraviolet light.
Strong Plasmon–Exciton Interactions on Nanoantenna Array–Monolayer WS2 Hybrid System
Authors: Liu Lin , Tobing Landobasa Y. M. , Yu Xuechao , Tong Jinchao , Qiang Bo , Fernández‐Domínguez Antonio I. , Garcia‐Vidal Francisco J. , Zhang Dao Hua , Wang Qi Jie , Luo Yu
Published: September 2019

Strong plasmon–exciton interactions in monolayer transition‐metal dichalcogenides (TMDs) is emerging as a promising material platform for light emissions, nonlinear optics, and quantum communications, and their realizations require highly localized electric fields parallel to the transition dipole moment of TMD excitons. Here, a systematic study of light–matter interaction in planar dimer nanoantenna of nanoscale gaps coupled with monolayer WS2 is presented, where the effects of the local field enhancement and spatial mode overlap in the plasmon–exciton coupling strength are experimentally investigated. Importantly, anticrossing behaviors in the strong coupling regime with a Rabi splitting of Ω = 118 meV for gold bowtie antennas with 7 nm gaps and Ω = 138 meV for gold dimer arrays with 10 nm gaps are demonstrated.
Heavy Mn2+ Doped MgAl2O4 Phosphor for High‐Efficient Near‐Infrared Light‐Emitting Diode and the Night‐Vision Application
Authors: Song Enhai , Jiang Xingxing , Zhou Yayun , Lin Zheshuai , Ye Shi , Xia Zhiguo , Zhang Qinyuan
Published: September 2019

Photoluminescence originated from doped activators in the solid state materials usually faces the challenge of concentration quenching, restricting the further increase of photoluminescence intensity. Herein, a new strategy is demonstrated by the heavy doping Mn2+ into MgAl2O4, leading to the broad‐band near‐infrared (NIR) emission peaking at ≈825 nm with a full width at half maximum of ≈125 nm, as well as high internal quantum efficiency of ≈53% upon 450 nm laser excitation. Density functional theory calculation and extend X‐ray absorption fine structure provide a understanding of Al3+/Mn2+ disorder and Mn2+–Mn2+ aggregation in spinel Mg1–xAl2O4:xMn2+ with high Mn2+ content, which enables the formation of superexchange coupled IVMn2+–VIMn2+ pair. The NIR light‐emitting diodes fabricated by the 450 nm blue chip and Mg0.50Al2O4:0.50Mn2+ phosphor gives a high NIR output power of ≈78.41 mW under a driven current of 120 mA, and night‐vision application as light source in the dark is demonstrated. This work opens new paths for rational design of efficient broad‐band NIR emitting phosphor, and also provides new insights into the Mn2+ luminescence and the applications.
Mechanochemical Oxidative Heck Coupling of Activated and Unactivated Alkenes: A Chemo‐, Regio‐ and Stereo‐Controlled Synthesis of Alkenylbenzenes
Authors: Yu Jingbo , Shou Haowen , Yu Wangyang , Chen Haodong , Su Weike
Published: September 2019

In this work, we present an efficient mechanochemical strategy for chemo‐, regio‐ and stereo‐selective oxidative Heck coupling of readily accessible arylboron reagents/heteroaromatics with cyclic and acyclic olefins. Mono‐ and bis‐arylation were achieved without the need of ligands, directing groups or prefunctionalized alkenes, and the reaction chemo‐selectivity could be controlled by tuning of the oxidative system. This protocol offers the synthesis of alkenylbenzenes in broad substrate scope, satisfactory yields and excellent selectivity even in the gram scale.

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Phylogenomics in Cactaceae: A case study using the chollas sensu lato (Cylindropuntieae, Opuntioideae) reveals a common pattern out of the Chihuahuan and Sonoran deserts
Authors: Majure Lucas C. , Baker Marc A. , Cloud‐Hughes Michelle , Salywon Andrew , Neubig Kurt M.
Published: September 2019

Premise

Although numerous phylogenetic studies have been conducted in Cactaceae, whole‐plastome datasets have not been employed. We used the chollas to develop a plastome dataset for phylogeny reconstruction to test species relationships, biogeography, clade age, and morphological evolution.

Methods

We developed a plastome dataset for most known diploid members of the chollas (42 taxa) as well as for other members of Cylindropuntieae. Paired‐end, raw reads from genome skimming were reference‐mapped onto a de novo plastome assembly of one species of cholla, Cylindropuntia bigelovii, and were used to build our plastome dataset, which was analyzed using various methods.

Results

Our plastome dataset resolved the phylogeny of the chollas, including most interspecific and intraspecific relationships. Tribe Cylindropuntieae arose ~18 mya, during the early Miocene in southern South America, and is supported as sister to the South American clade Tephrocacteae. The (Micropuntia (Cylindropuntia + Grusonia)) clade most likely originated in the Chihuahuan Desert region around 16 mya and then migrated into other North American desert regions. Key morphological characters for recognizing traditional taxonomic series in Cylindropuntia (e.g., spiny fruit) are mostly homoplasious.

Conclusions

This study provides the first comprehensive plastome phylogeny for any clade within Cactaceae. Although the chollas s.l. are widespread throughout western North American deserts, their most recent common ancestor likely arose in the Chihuahuan Desert region during the mid‐Miocene, with much of their species diversity arising in the early to mid‐Pliocene, a pattern strikingly similar to those found in other western North American desert groups.
Manganese‐Catalyzed Oxime‐Directed ortho‐C−H Amidation in Ionic Liquids
Authors: Kong Xianqiang , Xu Bo
Published: September 2019

We have developed an efficient amidation of aromatic oximes via C−H bond activation using readily available sulfonyl azides as amidation reagents. This reaction is catalyzed by a base metal catalyst system – MnBr(CO)5/[Hmim]OTf. Our method offers excellent chemical yields and regioselectivity with good functional group tolerance. The reusability of MnBr(CO)5/[Hmim]OTf system makes it relatively practical for large scale C−H amidations.
Synthesis of α‐Substituted Succinimides from Glyoxal and Ketene N,S‐Acetals
Authors: Xu Qi , Zheng Baihui , Pan Ling , Liu Qun , Li Yifei
Published: September 2019

The reaction of ketene N,S‐acetals with glyoxal for the efficient synthesis of α‐ketosuccinimides is described. Promoted by concentrated hydrobromide, the reaction proceeded under mild aqueous, metal‐free conditions, with broad substrate tolerance. As a result, one C−C, one C−N, and one C−O bond were formed. Mechanistic studies show that this tandem process involves enamine addition, hydrolysis and intramolecular nucleophilic addition. In the proposed mechanism, the amine released as a byproduct plays a promoter role to accelerate the construction of α‐ketosuccinimides.
Intramolecular Arylative Ring Opening of Donor‐Acceptor Cyclopropanes in the Presence of Triflic Acid: Synthesis of 9H‐Fluorenes and 9,10‐Dihydrophenanthrenes
Authors: Wang Dongyang , Zhao Jing , Chen Jun , Xu Qing , Li Huan
Published: September 2019

A unique intramolecular arylative ring opening of 2‐biaryl substituted donor‐acceptor cyclopropanes in the presence of triflic acid was found, furnishing 9H‐fluorenes and 9,10‐dihydrophenanthrenes. Chemoselectivity between both products is achieved by modification of the solvent, temperature, and amount of triflic acid. Representative large‐scale experiments were also carried out successfully with good outcomes.
Infiltration pattern of gammadelta T cells and its association with local inflammatory response in the nasal mucosa of patients with allergic rhinitis
Authors: Yang Qintai , Li Chunwei , Wang Weihao , Zheng Rui , Huang Xuekun , Deng Huiyi , Jin Peng , Tan Kaisen , Yan Yan , Wang Deyun
Published: September 2019

Background

gammadelta (γδ) T cells play important roles in allergic lower airway inflammation. However, little is known about their infiltration pattern in the nasal mucosa during upper airway inflammation. This study investigated γδ T cell distribution in nasal tissues of allergic rhinitis (AR) patients and the relationship between γδ T cells and other inflammatory cell types.

Methods

A total of 30 patients with septal deviation were examined, including 22 with and 8 without AR. The localization of γδ T cells and other cells (eosinophils, neutrophils, mast cells, macrophages, B cells, cluster of differentiation [CD]4+ T cells, CD8+ T cells, regulatory T cells [Tregs], interferon [IFN]‐γ+ cells, interleukin [IL]17+ cells, and IL10+ cells) was evaluated by histological analysis and immunohistochemistry. T helper cell (Th)1/Th2/Th17 and Treg gene expression was analyzed by quantitative polymerase chain reaction (PCR).

Results

γδ T cells were localized in the epithelium or subepithelial region of nasal mucosa, and their infiltration was higher in AR patients relative to control subjects. The number of γδ T cells was associated with the presence of eosinophils, macrophages, mast cells, B cells, CD8+ T cells, Forkhead box (Fox)p3+ Tregs, IL17+ cells, and IL10+ cells but not of neutrophils or IFN‐γ+ cells. The messenger RNA (mRNA) level of a γδ T cell subunit was positively correlated with those of Th1 genes (T‐bet and IFN‐γ), Th2 cytokine (C‐C motif chemokine ligand 18), and Treg genes (Foxp3 and IL10).

Conclusion

γδ T cells play multiple roles in mucosal inflammation in AR including immune surveillance and adaptive and innate immune responses.
The Microscopic Structure–Property Relationship of Metal–Organic Polyhedron Nanocomposites
Authors: Zhang Mingxin , Lai Yuyan , Li Mu , Hong Tao , Wang Weiyu , Yu Haitao , Li Lengwan , Zhou Qianjie , Ke Yubin , Zhan Xiaozhi , Zhu Tao , Huang Caili , Yin Panchao
Published: September 2019

Monodispersed hairy nanocomposites with typical 2 nm (isophthalic acid)24Cu24 metal–organic polyhedra (MOP) as a core protected by 24 polymer chains with controlled narrow molecular weight distribution has been probed by imaging and scattering studies for the heterogeneity of polymers in the nanocomposites and the confinement effect the MOPs imposing on anchored polymers. Typical confined‐extending surrounded by one entanglement area is proposed to describe the physical states of the polymer chains. This model dictates the counterintuitive thermal and rheological properties and prohibited solvent exchange properties of the nanocomposites, whilst those polymer chain states are tunable and deterministic based on their component inputs. From the relationship between the structure and behavior of the MOP nanocomposites, a MOP‐composited thermoplastic elastomer was obtained, providing practical solutions to improve mechanical/rheological performances and processabilities of inorganic MOPs.
Ion‐Mobility Spectrometry Can Assign Exact Fucosyl Positions in Glycans and Prevent Misinterpretation of Mass‐Spectrometry Data After Gas‐Phase Rearrangement
Authors: Sastre Toraño Javier , Gagarinov Ivan A. , Vos Gaël M. , Broszeit Frederik , Srivastava Apoorva D. , Palmer Martin , Langridge James I. , Aizpurua‐Olaizola Oier , Somovilla Victor J. , Boons Geert‐Jan
Published: September 2019

The fucosylation of glycans leads to diverse structures and is associated with many biological and disease processes. The exact determination of fucoside positions by tandem mass spectrometry (MS/MS) is complicated because rearrangements in the gas phase lead to erroneous structural assignments. Here, we demonstrate that the combined use of ion‐mobility MS and well‐defined synthetic glycan standards can prevent misinterpretation of MS/MS spectra and incorrect structural assignments of fucosylated glycans. We show that fucosyl residues do not migrate to hydroxyl groups but to acetamido moieties of N‐acetylneuraminic acid as well as N‐acetylglucosamine residues and nucleophilic sites of an anomeric tag, yielding specific isomeric fragment ions. This mechanistic insight enables the characterization of unique IMS arrival‐time distributions of the isomers which can be used to accurately determine fucosyl positions in glycans.
Engineering of Ruthenium–Iron Oxide Colloidal Heterostructures: Improved Yields in CO2 Hydrogenation to Hydrocarbons
Authors: Aitbekova Aisulu , Goodman Emmett D. , Wu Liheng , Boubnov Alexey , Hoffman Adam S. , Genc Arda , Cheng Huikai , Casalena Lee , Bare Simon R. , Cargnello Matteo
Published: September 2019

Catalytic CO2 reduction to fuels and chemicals is a major pursuit in reducing greenhouse gas emissions. One approach utilizes the reverse water‐gas shift reaction, followed by Fischer–Tropsch synthesis, and iron is a well‐known candidate for this process. Some attempts have been made to modify and improve its reactivity, but resulted in limited success. Now, using ruthenium–iron oxide colloidal heterodimers, close contact between the two phases promotes the reduction of iron oxide via a proximal hydrogen spillover effect, leading to the formation of ruthenium–iron core–shell structures active for the reaction at significantly lower temperatures than in bare iron catalysts. Furthermore, by engineering the iron oxide shell thickness, a fourfold increase in hydrocarbon yield is achieved compared to the heterodimers. This work shows how rational design of colloidal heterostructures can result in materials with significantly improved catalytic performance in CO2 conversion processes.
Electron Transfer in DNA at Electrified Interfaces
Authors: Ferapontova Elena E.
Published: September 2019

The ability of the DNA double helix to transport electrons underlies many life‐centered biological processes and bio‐electronic applications. However, there is little consensus on how efficiently the base pair π‐stacks of DNA mediate electron transport. This minireview scrutinizes the current state‐of‐the‐art knowledge on electron transfer (ET) properties of DNA and its long‐range ability to transfer (mediate) electrical signals at electrified interfaces, without being oxidized or reduced. Complex changes an electric field induces in the DNA structure and its electronic properties govern the efficiency of DNA‐mediated ET at electrodes and allow addressing the existing phenomenological riddles, while recently discovered rectifying properties of DNA contribute both to our understanding of DNA′s ET in living systems and to advances in molecular bioelectronics.
Entrapment of a Pseudo‐Tetrahedral CoII Center by Thioether Sulfur Bound {Co2(μ‐L)} Fragments: Synthesis, Field‐Induced Single‐Ion Magnetism and Catechol Oxidase Mimicking Activity
Authors: Das Manisha , Basak Dipmalya , Trávníček Zdeněk , Vančo Ján , Ray Debashis
Published: September 2019

Simultaneous incorporation of both CoII and CoIII ions within a new thioether S‐bearing phenol‐based ligand system, H3L (2,6‐bis‐[{2‐(2‐hydroxyethylthio)ethylimino}methyl]‐4‐methylphenol) formed [Co5] aggregates [CoIICoIII4L2(μ‐OH)2(μ1,3‐O2CCH3)2](ClO4)4⋅H2O (1) and [CoIICoIII4L2(μ‐OH)2(μ1,3‐O2CC2H5)2](ClO4)4⋅H2O (2). The magnetic studies revealed axial zero‐field splitting (ZFS) parameter, D/hc=−23.6 and −24.3 cm−1, and E/D=0.03 and 0.00, respectively for 1 and 2. Dynamic magnetic data confirmed the complexes as SIMs with Ueff/kB=30 K (1) and 33 K (2), and τ0=9.1×10−8 s (1), and 4.3×10−8 s (2). The larger atomic radius of S compared to N gave rise to less variation in the distortion of tetrahedral geometry around central CoII centers, thus affecting the D and Ueff/kB values. Theoretical studies also support the experimental findings and reveal the origin of the anisotropy parameters. In solutions, both 1 and 2 which produce {CoIII2(μ‐L)} units, display solvent‐dependent catechol oxidation behavior toward 3,5‐di‐tert‐butylcatechol in air. The presence of an adjacent CoIII ion tends to assist the electron transfer from the substrate to the metal ion center, enhancing the catalytic oxidation rate.
Ag Nanoparticles Supported on a Resorcinol‐Phenylenediamine‐Based Covalent Organic Framework for Chemical Fixation of CO2
Authors: Chakraborty Debanjan , Shekhar Pragalbh , Singh Himan Dev , Kushwaha Rinku , Vinod C. P. , Vaidhyanathan Ramanathan
Published: September 2019

Covalent organic frameworks are a new class of crystalline organic polymers possessing a high surface area and ordered pores. Judicious selection of building blocks leads to strategic heteroatom inclusion into the COF structure. Owing to their high surface area, exceptional stability and molecular tunability, COFs are adopted for various potential applications. The heteroatoms lining in the pores of COF favor synergistic host–guest interaction to enhance a targeted property. In this report, we have synthesized a resorcinol‐phenylenediamine‐based COF which selectively adsorbs CO2 into its micropores (12 Å). The heat of adsorption value (32 kJ mol−1) obtained from the virial model at zero‐loading of CO2 indicates its favorable interaction with the framework. Furthermore, we have anchored small‐sized Ag nanoparticles (≈4–5 nm) on the COF and used the composite for chemical fixation of CO2 to alkylidene cyclic carbonates by reacting with propargyl alcohols under ambient conditions. Ag@COF catalyzes the reaction selectively with an excellent yield of 90 %. Recyclability of the catalyst has been demonstrated up to five consecutive cycles. The post‐catalysis characterizations reveal the integrity of the catalyst even after five reaction cycles. This study emphasizes the ability of COF for simultaneous adsorption and chemical fixation of CO2 into corresponding cyclic carbonates.
Protective effect of glycyrrhizic acid on cerebral ischemia/reperfusion injury via inhibiting HMGB1‐mediated TLR4/NF‐κB pathway
Authors: Yan Sunhong , Fang Chuanqin , Cao Lei , Wang Long , Du Jing , Sun Yue , Tong Xuanxia , Lu Ying , Wu Xiaosan
Published: September 2019

Cerebral ischemia is caused by various disorders, such as stroke, myocardial infarction, or peripheral vascular disease. The purpose of this paper was to investigate the effects of glycyrrhizic acid (GA) on cerebral ischemia/reperfusion (I/R) injury. Middle cerebral artery occlusion was established to evaluate the effects of GA on cerebral ischemia. In this study, our results showed that GA could dramatically decrease cerebral edema, reduce the neurological deficits, and smaller brain infarct volume was found in the GA treatment group. In serum and brain tissue, GA also increased superoxide dismutase activity. In addition, in serum and brain tissue, GA also dramatically inhibited the secretion of inflammatory cytokines, including interleukin‐1β (IL‐1β), IL‐6, and tumor necrosis factor‐α. Moreover, GA inhibited the expressions of high‐mobility group protein box‐1 (HMGB1)‐mediated TLR4/NF‐κB pathway. Our data determined that GA may provide protective effect on the I/R‐induced cerebral ischemia disease.
Joint mean–covariance random effect model for longitudinal data
Authors: Bai Yongxin , Qian Manling , Tian Maozai
Published: September 2019

In this paper, we consider the inherent association between mean and covariance in the joint mean–covariance modeling and propose a joint mean–covariance random effect model based on the modified Cholesky decomposition for longitudinal data. Meanwhile, we apply M‐H algorithm to simulate the posterior distributions of model parameters. Besides, a computationally efficient Monte Carlo expectation maximization (MCEM) algorithm is developed for carrying out maximum likelihood estimation. Simulation studies show that the model taking into account the inherent association between mean and covariance has smaller standard deviations of the estimators of parameters, which makes the statistical inferences much more reliable. In the real data analysis, the estimation of parameters in the mean and covariance structure is highly efficient.
Microporous scaffolds loaded with immunomodulatory lentivirus to study the contribution of immune cell populations to tumor cell recruitment in vivo
Authors: Bushnell Grace G. , Rao Shreyas S. , Hartfield Rachel M. , Zhang Yining , Oakes Robert S. , Jeruss Jacqueline S. , Shea Lonnie D.
Published: September 2019

Metastases are preceded by stochastic formation of a hospitable microenvironment known as the premetastatic niche, which has been difficult to study. Herein, we employ implantable polycaprolactone scaffolds as an engineered premetastatic niche to independently investigate the role of interleukin‐10 (IL10), CXCL12, and CCL2 in recruiting immune and tumor cells and impacting breast cancer cell phenotype via lentiviral overexpression. Lentivirus delivered from scaffolds in vivo achieved sustained transgene expression for 56 days. IL10 lentiviral expression, but not CXCL12 or CCL2, significantly decreased tumor cell recruitment to scaffolds in vivo. Delivery of CXCL12 enhanced CD45+ immune cell recruitment to scaffolds while delivery of IL10 reduced immune cell recruitment. CCL2 did not alter immune cell recruitment. Tumor cell phenotype was investigated using conditioned media from immunomodulated scaffolds, with CXCL12 microenvironments reducing proliferation, and IL10 microenvironments enhancing proliferation. Migration was enhanced with CCL2 and reduced with IL10‐driven microenvironments. Multiple linear regression identified populations of immune cells associated with tumor cell abundance. CD45+ immune and CD8+ T cells were associated with reduced tumor cell abundance, while CD11b+Gr1+ neutrophils and CD4+ T cells were associated with enhanced tumor cell abundance. Collectively, biomaterial scaffolds provide a tool to probe the formation and function of the premetastatic niche.
Volatile fatty acids as novel building blocks for oil‐based chemistry via oleaginous yeast fermentation
Authors: Llamas Mercedes , Magdalena Jose Antonio , González‐Fernández Cristina , Tomás‐Pejó Elia
Published: September 2019

Microbial oils are proposed as a suitable alternative to petroleum‐based chemistry in terms of environmental preservation. These oils have traditionally been studied using sugar‐based feedstock, which implies high costs, substrate limitation, and high contamination risks. In this sense, low‐cost carbon sources such as volatile fatty acids (VFAs) are envisaged as promising building blocks for lipid biosynthesis to produce oil‐based bioproducts. VFAs can be generated from a wide variety of organic wastes through anaerobic digestion and further converted into lipids by oleaginous yeasts (OYs) in a fermentation process. These microorganisms can accumulate in the form of lipid bodies, lipids of up to 60% wt/wt of their biomass. In this context, OY is a promising biotechnological tool for biofuel and bioproduct generation using low‐cost VFA media as substrates. This review covers recent advances in microbial oil production from VFAs. Production of VFAs via anaerobic digestion processes and the involved metabolic pathways are reviewed. The main challenges as well as recent approaches for lipid overproduction are also discussed.
Volatile and Sensory Profiles of Algerian Extra‐Virgin Olive Oil from Souidi and Zeletni Cultivars
Authors: Cherfaoui Maya , Cecchi Teresa , Keciri Sonia , Boudriche Lilya
Published: September 2019

In this study, the volatile and sensory profiles of monovarietal extra‐virgin olive oil (EVOO) from two less widespread Algerian autochthonous cultivars (Souidi and Zeletni) were obtained using headspace solid‐phase microextraction coupled to gas chromatography‐mass spectrometry and a panel test, respectively. A total of 14 and 10 volatile compounds belonging to different chemical classes were identified and quantified in the Souidi and Zeletni EVOOs, respectively. Zeletni EVOO contains 2.07 times more (E)‐2‐hexenal than Souidi EVOO. In addition, the amounts of C6 compounds from LA and LnA, as well as the total amount of the compounds of the LOX pathway were higher in Zeletni than in the Souidi EVOO. Another important finding was the predominance of sesquiterpene β‐ocimene in the composition of the volatile fraction of Souidi EVOO. The sensory profiles of the EVOOs analyzed were characterized by fruity, bitter and pungent sensory positive attributes, perceived at medium intensity in both oils studied.
Synthesis and Relaxometric Characterization of New Poly[N,N‐bis(3‐aminopropyl)glycine] (PAPGly) Dendrons Gd‐Based Contrast Agents and Their in Vivo Study by Using the Dynamic Contrast‐Enhanced MRI Technique at Low Field (1 T)
Authors: Granato Luigi , Longo Dario , Boutry Sébastien , Vander Elst Luce , Henoumont Céline , Aime Silvio , Muller Robert N. , Laurent Sophie
Published: September 2019

The synthesis of poly[N,N‐bis(3‐aminopropyl)glycine] (PAPGly) dendrons Gd‐based contrast agents (GdCAs) via an orthogonal protection of the different functional groups and an activation/coupling strategy wherein a specific number of synthetic steps add a generation to the existing dendron has been described. The aim of this protocol is to build up two different generations of dendrons (G‐0 or dendron's core, and G‐1) with peripheral NH2 groups to conjugate a 1,4,7,10‐tetraazacyclododecane‐1,4,7‐triacetic acid (DO3A) derivative and afterwards to chelate with Gd3+ paramagnetic ions. These complexes, which have a well‐defined molecular weight, are of relevance to MRI as an attempt to gain higher 1H relaxivity by slowing down the rotation of molecule compared to monomeric Gd(III) complexes used as contrast agents and to increase the number of paramagnetic centers present in one molecular structure. From the study of their water 1H longitudinal relaxation rate at different magnetic fields (NMRD, Nuclear Magnetic Relaxation Dispersion) and by evaluating the variable temperature 17O‐NMR data we determined the parameters characterizing the water exchange rate and the rotational correlation time of each complex, both affecting 1H relaxivity. Furthermore, these two novel PAPGly GdCAs were objects of i) an in vivo study to determine their biodistributions in healthy C57 mice at several time points, and ii) the Dynamic Contrast‐Enhanced MRI (DCE‐MRI) approach to assess their contrast efficiency measured in the tumor region of C57BL/6 mice transplanted subcutaneously with B16‐F10 melanoma cells. The aim of the comparison of these two dendrons GdCAs, having different molecular weights (MW), is to understand how MW and relaxivity may influence the contrast enhancement capabilities in vivo at low magnetic field (1 T). Significant contrast enhancement was observed in several organs (vessel, spleen and liver), already at 5 min post‐injection, for the investigated CAs. Moreover, these CAs induced a marked contrast enhancement in the tumor region, thanks to the enhanced permeability retention effect of those macromolecular structures.
Highly Sensitive RNA‐Cleaving DNAzyme Sensors from Surface‐to‐Surface Product Enrichment
Authors: Samani Sahar Esmaeili , Chang Dingran , McConnell Erin M. , Rothenbroker Meghan , Filipe Carlos D. M. , Li Yingfu
Published: September 2019

The engineering of easy‐to‐use biosensors with ultra‐low detection sensitivity remains a major challenge. Herein, we report a simple approach for creating such sensors through the use of an RNA‐cleaving DNAzyme (RcD) and a strategy designed to concentrate its cleavage product significantly. The assay uses micron‐sized beads loaded with a target‐responsive RcD and a paper strip containing a microzone covered with a DNA oligonucleotide capable of capturing the cleavage product of the RcD through Watson–Crick hybridization. Placing the beads and the paper strip in a target‐containing test sample allows the bead‐bound RcD molecules to undergo target‐induced RNA cleavage, releasing a DNA fragment that is captured by the paper strip. This strategy, though simple, is very effective in achieving high levels of detection sensitivity, being able to enrich the concentration of the cleavage product by three orders of magnitude. It is also compatible with both fluorescence‐based and colorimetric reporting mechanisms. This work provides a simple platform for developing ultrasensitive biosensors that take advantage of the widely available RcDs as molecular recognition elements.
Does the Zn2+Species Introduced into H‐ZSM‐5 Zeolite Affect the Strength of Brønsted Acid Sites?
Authors: Gabrienko Anton A. , Danilova Irina G. , Arzumanov Sergei S. , Freude Dieter , Stepanov Alexander G.
Published: September 2019

To clarify the issue on Brønsted acidity enhancement by the presence of zinc species in H‐ZSM‐5 zeolite (G.D. Qi, et al.,Angew. Chem.‐Int. Edit.2016,55, 15826), the influence of Zn2+cationic species, introduced into the zeolite, on the strength of Brønsted acid sites (BAS) has been analyzed by solid‐state NMR and FTIR techniques using trimethylphosphine (TMP) and CO as probe molecules. Comparative analysis of the acidity for H‐ZSM‐5 and Zn2+/H‐ZSM‐5 zeolites has been performed. TMP adsorbed on both zeolite samples exhibits same signals at 6.3 and −4.5 ppm in1H and31P MAS NMR spectra, respectively, assigned to protonated TMP. FTIR spectroscopy has shown that both zeolite samples, H‐ZSM‐5 and Zn2+/H‐ZSM‐5, display the same red frequency shift (ΔνOH⋅⋅⋅CO=−318 cm−1) of the O−H stretching band and the same blue frequency shift (ΔνCO=+32 cm−1) of the CO stretching band for CO adsorption complex with BAS. The results obtained do not provide any evidence for the existence of some specific BAS with enhanced acid strength for Zn2+‐exchanged zeolite compared to the strength inherent to pure acid‐form zeolite. It is thus inferred the strength of BAS in H‐ZSM‐5 zeolite is not affected by the modification of the zeolite with Zn2+cationic species.
Targeted Construction of Amorphous MoSx with an Inherent Chain Molecular Structure for Improved Pseudocapacitive Lithium‐Ion Response
Authors: Wang Yao‐Yao , Fan Hong‐Hong , Wang Zhi‐Wei , Diao Wan‐Yue , Fan Chao‐Ying , Wu Xing‐Long , Zhang Jing‐Ping
Published: September 2019

Owing to low ion/electron conductivity and large volume change, transitional metal dichalcogenides (TMDs) suffer from inferior cycle stability and rate capability when used as the anode of lithium‐ion batteries (LIBs). To overcome these disadvantages, amorphous molybdenum sulfide (MoSx) nanospheres were prepared and coated with an ultrathin carbon layer through a simple one‐pot reaction. Combining X‐ray photoelectron spectroscopy (XPS) with theoretical calculations, MoSx was confirmed as having a special chain molecular structure with two forms of S bonding (S2− and S22−), the optimal adsorption sites of Li+ were located at S22−. As a result, the MoSx electrode exhibits superior cycle and rate capacities compared with crystalline 2H‐MoS2 (e.g., delivering a high capacity of 612.4 mAh g−1 after 500 cycles at 1 A g−1). This is mainly attributed to more exposed active S22− sites for Li storage, more Li+ transfer pathways for improved ion conductivity, and suppressed electrode structure pulverization of MoSx derived from the inherent chain‐like molecular structure. Quantitative charge storage analysis further demonstrates the improved pseudocapacitive contribution of amorphous MoSx induced by fast reaction kinetics. Moreover, the morphology contrast after cycling demonstrates the dispersion of active materials is more uniform for MoSx than 2H‐MoS2, suggesting the MoSx can well accommodate the volume stress of the electrode during discharging. Through regulating the molecular structure, this work provides an effective targeted strategy to overcome the intrinsic issues of TMDs for high‐performance LIBs.
The Role of LiBr and ZnBr2 on the Cross‐Coupling of Aryl Bromides with Bu2Zn or BuZnBr
Authors: Eckert Philip , Organ Michael G.
Published: September 2019

The impact of LiBr and ZnBr2 salts on the Negishi coupling of alkylZnBr and dialkylzinc nucleophiles with both electron‐rich and ‐poor aryl electrophiles has been examined. Focusing only on the more difficult coupling of deactivated (electron‐rich) oxidative addition partners, LiBr promotes coupling with BuZnBr, but does not have such an effect with Bu2Zn. The presence of exogenous ZnBr2 shuts down the coupling of both BuZnBr and Bu2Zn, which has been shown before with alkyl electrophiles. Strikingly, the addition of LiBr to Bu2Zn reactions containing exogenous ZnBr2 now fully restores coupling to levels seen without any salt present. This suggests that there is a very important interaction between LiBr and ZnBr2. It is proposed that Lewis acid adducts are forming between ZnBr2 and the electron‐rich Pd0 centre and the bromide from LiBr forms inorganic zincates that prevent the catalyst from binding to ZnBr2. This idea has been supported by catalyst design as chlorinating the backbone of the NHC ring of Pd‐PEPPSI‐IPent to produce Pd‐PEPPSI‐IPentCl catalyst now gives quantitative conversion, up from a ceiling of only 50 % with the former catalyst.
Anticancer Activity of Electron‐Deficient Metal Complexes against Colorectal Cancer in vitro Models
Authors: Azmanova Maria , Soldevila‐Barreda Joan , Bani Hani Hira , Lord Rianne M. , Pitto‐Barry Anaïs , Picksley Steven M. , Barry Nicolas P. E.
Published: September 2019

An evaluation of the in vitro cytotoxicity of nine electron‐deficient half‐sandwich metal complexes towards two colorectal cancer cell lines (HCT116 p53+/+, HCT116 p53−/−) and one normal prostate cell line (PNT2) is presented herein. Three complexes were found to be equally cytotoxic towards both colorectal cancer cell lines, suggesting a p53‐independent mechanism of action. These complexes are 12 to 34× more potent than cisplatin against HCT116 p53+/+ and HCT116 p53−/− cells. Furthermore, they were found to exhibit little or no cytotoxicity towards PNT2 normal cells, with selectivity ratios greater than 50. To gain an insight into the potential mechanisms of action of the most active compounds, their effects on the expression levels of a panel of genes were measured using qRT‐PCR against treated HCT116 p53+/+ and HCT116 p53−/− cells, and cell‐cycle analysis was carried out.
The clinical conundrum of managing 5‐fluorouracil–induced vasospasm in colorectal carcinoma
Authors: Nohria Anju
Published: September 2019

Fluoropyrimidine‐associated cardiotoxicity can be a therapy‐limiting adverse effect that largely depends on the mode of fluoropyrimidine administration. We discuss strategies for re‐challenge after incident cardiotoxicity that can reduce, but not eliminate, the risk of recurrent cardiotoxicity.
HER2 assessment by bright‐field dual in situ hybridization in cell blocks of recurrent and metastatic breast carcinoma
Authors: Edelweiss Marcia , Sebastiao Ana Paula Martins , Oen Handy , Kracun Mihaela , Serrette Rene , Ross Dara S.
Published: September 2019

Background

Breast cancer recurrences or metastases often are diagnosed using cytology material. Cell blocks (CBs) with adequate cellularity are crucial for the determination of accurate hormonal and human epidermal growth factor receptor 2 (HER2) status and to guide treatment. In the current study, the authors evaluated the concordance of HER2 status between bright‐field dual in situ hybridization (DISH), fluorescence in situ hybridization (FISH), and HER2 immunohistochemistry (IHC) performed on formalin‐fixed CBs of recurrent and metastatic breast cancers.

Methods

The authors searched for patients who had breast carcinoma recurrences or metastases diagnosed between 2010 and 2018 by fine‐needle aspiration or by the drainage of body cavity fluids with HER2 IHC and/or FISH performed on formalin‐fixed CBs. Cases with adequate tumor cellularity (>50 cells) were selected. HER2 DISH was performed on all CBs. HER2 status of the primary breast carcinoma was recorded.

Results

Formalin‐fixed CBs were identified from 30 patients with breast cancer recurrences and metastases in axillary lymph nodes (LNs) (5 patients), mediastinal LNs (8 patients), internal mammary LNs (1 patient), supraclavicular LNs (2 patients), portocaval LNs (1 patient), chest wall (3 patients), pleural fluid (3 patients), bone (4 patients), liver (2 patients), and lung (1 patient). All cases had HER2 IHC performed at the study institution and were scored by breast pathologists according to the American Society of Clinical Oncology/College of American Pathologists guidelines. The HER2 DISH results demonstrated 100% concordance (30 of 30 cases) with the concurrent IHC and/or FISH.

Conclusions

All methods of HER2 evaluation were found to accurately identify the amplification status. DISH can be used in tandem with IHC as a reflex assay instead of FISH and is an efficient and reliable method with which to determine HER2 amplification in formalin‐fixed CBs.
Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT‐MD Study of Dibenzoylmethane in Methanol Solution
Authors: Milovanović Branislav , Stanković Ivana M. , Petković Milena , Etinski Mihajlo
Published: September 2019

The dynamic aspect of solvation plays a crucial role in determining properties of strong intramolecular hydrogen bonds since solvent fluctuations modify instantaneous hydrogen‐bonded proton transfer barriers. Previous studies pointed out that solvent‐solute interactions in the first solvation shell govern the position of the proton but the ability of the electric field due to other solvent molecules to localize the proton remains an important issue. In this work, we examine the structure of the O−H⋅⋅⋅O intramolecular hydrogen bond of dibenzoylmethane in methanol solution by employing density functional theory‐based molecular dynamics and quantum chemical calculations. Our computations showed that homogeneous electric fields with intensities corresponding to those found in polar solvents are able to considerably alter the proton transfer barrier height in the gas phase. In methanol solution, the proton position is correlated with the difference in electrostatic potentials on the oxygen atoms of dibenzoylmethane even when dibenzoylmethane‐methanol hydrogen bonding is lacking. On a timescale of our simulation, the hydrogen bonding and solvent electrostatics tend to localize the proton on different oxygen atoms. These findings provide an insight into the importance of the solvent electric field on the structure of a strong intramolecular hydrogen bond.
Development of a Disease Progression Model for Leucine‐Rich Repeat Kinase 2 in Parkinson's Disease to Inform Clinical Trial Designs
Authors: Ahamadi Malidi , Conrado Daniela J , Macha Sreeraj , Sinha Vikram , Stone Julie , Burton Jackson , Nicholas Timothy , Gallagher Jill , Dexter David , Bani Massimo , Boroojerdi Babak , Smit Hans , Weidemann Jonas , Chen Chao , Yang Minhua , Maciuca Romeo , Lawson Rachael , Burn David , Marek Kenneth , Venuto Charles , Stafford Bob , Akalu Mussie , Stephenson Diane , Romero Klaus ,   on behalf of the Critical Path for Parkinson's (CPP) Consortium
Published: September 2019

A quantitative assessment of Parkinson's disease (PD) progression is critical for optimizing clinical trials design. Disease progression model was developed using pooled data from the Progression Marker Initiative study and the Incidence of Cognitive Impairment in Cohorts with Longitudinal Evaluation in Parkinson's Disease study. Age, gender, concomitant medication, and study arms were predictors of baseline. A mutation in the leucine‐rich repeat kinase 2 (LRRK2) encoding gene was associated with the disease progression rate. The progression rate in subjects with PD who carried LRRK2 mutation was slightly slower (~0.170 points/month) than that in PD subjects without the mutation (~0.222 points/month). For a nonenriched placebo‐controlled clinical trial, approximately 70 subjects/arm would be required to detect a drug effect of 50% reduction in the progression rate with 80% probability, whereas 85, 93, and 100 subjects/arm would be required for an enriched clinical trial with 30%, 50%, and 70% subjects with LRRK2 mutations, respectively.
The ecology and evolution of seed predation by Darwin's finches on Tribulus cistoides on the Galápagos Islands
Authors: Carvajal‐Endara Sofía , Hendry Andrew P. , Emery Nancy C. , Neu Corey P. , Carmona Diego , Gotanda Kiyoko M. , Davies T. Jonathan , Chaves Jaime A. , Johnson Marc T. J.
Published: September 2019

Predator–prey interactions play a key role in the evolution of species traits through antagonistic coevolutionary arms races. The evolution of beak morphology in the Darwin's finches in response to competition for seed resources is a classic example of evolution by natural selection. The seeds of Tribulus cistoides are an important food source for the largest ground finch species (Geospiza fortis, G. magnirostris, and G. conirostris) in dry months, and the hard spiny morphology of the fruits is a potent agent of selection that drives contemporary evolutionary change in finch beak morphology. Although the effects of these interactions on finches are well known, how seed predation affects the ecology and evolution of the plants is poorly understood. Here we examine whether seed predation by Darwin's finches affects the ecology and evolution of T. cistoides. We ask whether the intensity of seed predation and the strength of natural selection by finches on fruit defense traits vary among populations, islands, years, or with varying finch community composition (i.e., the presence/absence of the largest beaked species, which feed on T. cistoides most easily). We then further test whether T. cistoides fruit defenses have diverged among islands in response to spatial variation in finch communities. We addressed these questions by examining seed predation by finches in 30 populations of T. cistoides over 3 yr. Our study reveals three key results. First, Darwin's finches strongly influence T. cistoides seed survival, whereby seed predation varies with differences in finch community composition among islands and in response to interannual fluctuations in precipitation. Second, finches impose phenotypic selection on T. cistoides fruit morphology, whereby smaller and harder fruits with longer or more spines exhibited higher seed survival. Variation in finch community composition and precipitation also explains variation in phenotypic selection on fruit defense traits. Third, variation in the number of spines on fruits among islands is consistent with divergent phenotypic selection imposed by variation in finch community composition among islands. These results suggest that Darwin's finches and T. cistoides are experiencing an ongoing coevolutionary arms race, and that the strength of this coevolution varies in space and time.
Transthyretin cardiac amyloidosis: an update on diagnosis and treatment
Authors: Yamamoto Hiroyuki , Yokochi Tomoki
Published: September 2019

Transthyretin cardiac amyloidosis (ATTR‐CA) demonstrates progressive, potentially fatal, and infiltrative cardiomyopathy caused by extracellular deposition of transthyretin‐derived insoluble amyloid fibrils in the myocardium. Two distinct types of transthyretin (wild type or variant) become unstable, and misfolding forms aggregate, resulting in amyloid fibrils. ATTR‐CA, which has previously been underrecognized and considered to be rare, has been increasingly recognized as a cause of heart failure with preserved ejection fraction among elderly persons. With the advanced technology, the diagnostic tools have been improving for cardiac amyloidosis. Recently, the efficacy of several disease‐modifying agents focusing on the amyloidogenic process has been demonstrated. ATTR‐CA has been changing from incurable to treatable. Nevertheless, there are still no prognostic improvements due to diagnostic delay or misdiagnosis because of phenotypic heterogeneity and co‐morbidities. Thus, it is crucial for clinicians to be aware of this clinical entity for early diagnosis and proper treatment. In this mini‐review, we focus on recent advances in diagnosis and treatment of ATTR‐CA.
Aminocatalytic Enantioselective 1, 6‐Addition of (Nitromethyl)benzenes to α, β, γ, δ‐Cyclic Dienones
Authors: Feng Kai‐Xiang , Shen Qiao‐Yu , Zheng Ya‐Yun , Xia Ai‐Bao , Zhou Zhan‐Yu , Tang Cheng‐Ke , Zhong Ai‐Guo , Xu Dan‐Qian , Du Xiao‐Hua
Published: September 2019

An excellent regio‐, and enantioselective 1,6‐addition of (nitromethyl)benzenes to α, β, γ, δ‐cyclic dienones via nitro‐Michael reactions has been developed. With the application of cinchona‐based primary amine catalysts, various chiral ε‐nitro ketene compounds were obtained in moderate to high yields (up to 84 %) with high to excellent enantioselectivities (up to > 99 % ee).
Do changes in threat salience predict the moral content of sermons? The case of Friday Khutbas in Turkey
Authors: Alper Sinan , Bayrak Fatih , Us Elif Öykü , Yilmaz Onurcan
Published: September 2019

We analyzed the content of “Friday Khutbas” delivered in Turkish mosques between January 2001 and December 2018 to test the prediction of moral foundations theory (MFT) literature that threat salience would lead to an increased endorsement of binding moral foundations. As societal‐level indicators of threat, we examined (a) historical data on the proportion of terrorism‐related news published in a Turkish newspaper, (b) the geopolitical risk score of Turkey as measured by Geopolitical Risk Index, and (c) Google Trends data on the search frequency of words “terror”, “terrorism”, or “terrorist”. To measure the endorsement of moral foundations, we built a Turkish Moral Foundations Dictionary and counted the relative frequency of morality‐related words in the khutbas delivered in Istanbul, Turkey. Time series analyses showed that risk salience in a certain month was positively related to endorsement of the loyalty/betrayal foundation in that month’s Friday Khutbas. There were mixed results for the other moral foundations.
The impact of net buying pressure on VIX option prices
Authors: Chuang Yi‐Wei , Tsai Wei‐Che , Wu Ming‐Hung
Published: September 2019

This paper analyzes the impact of intraday trading activity on option prices in the Volatility Index (VIX) options market. Our results show that there is a temporal relationship between net buying pressure (NBP) and changes in implied volatility of VIX options. Moreover, an increase in NBPs lowers the next‐day delta‐hedged option returns. Using several measures proxying for limits to arbitrage, the average levels of the implied volatility curve rise when limits to arbitrage are severe. A trading strategy in the VIX futures market constructed by using the NBP generates an average annualized return of 10.09%.