bluuebunny/crossref_metadata_2025_split huggingface dataset:
Double Twisted Photonic Honeycomb Frameworks with Mesoporous Structures
Authors: Nguyen Thanh‐Dinh , MacLachlan Mark J. 
Published: January 2019

AbstractIn nature, materials such as shell, bone, silk, and wood are assembled with hierarchical structures that span lengths from nanometers to centimeters. These biological materials are fascinating targets for replication and mimicry, often owing to their remarkable properties. The intricate and periodic structure of the snow crab (Chionoecetes opilio) exoskeleton that renders it iridescent is described here. It is discovered that the snow crab has a double twisted photonic honeycomb structure constructed by left‐handed rotation of chitin nanofibrils around cavities throughout its shell. This new chiral framework provides a foundation for exploring chiral photonics and materials. With the goal of mimicking this intricate network, the iridescent mineralized chitin shell is successfully transferred to calcite, carbon, apatite, and fluorapatite/chitin materials with structural replication. It is shown that the sophisticated organization of the iridescent crab shell leads these new materials to have a distinctive macroscopic combination of multilevel chirality, honeycomb channels, and mesoporosity. These solid‐state transformations of snow crab exoskeletons will open the path to making complex hierarchical frameworks of functional porous materials through bioinspired templating.
On‐Chip‐Integrated Methylammonium Halide Perovskite Optical Sensors
Authors: Sun Wenzhao , Huang Can , Fan Ruiqin , Liu Shuai , Wang Yujie , Xiao Yun‐Feng , Gan Qiaoqiang , Xiao Shumin , Song Qinghai 
Published: January 2019

AbstractLabel‐free, real‐time, portable, and cost‐effective detection of nanoscale objects is central to early‐stage detection of fatal diseases, environmental monitoring, homeland security, and so on. Owing to their extremely large Q/volume and enhanced light–matter interaction, micro‐ and nanophotonic sensors are intensively studied and their performances are significantly improved. To date, single molecule, single virus, and single nanoparticle have been successfully monitored with microscopic and spectroscopic systems, e.g., high‐Q microcavities and plasmonic devices. However, the current technologies suffer from drawbacks such as instability to ambient vibration, long analyzing time, and high costs. Their widespread uses, especially in portable point‐of‐care devices, are strongly hindered. Herein, taking full advantages of methylammonium lead tri‐halide (MAPbX3) perovskite, the perovskite photodetectors with Si3N4 waveguides are integrated and their potential in on‐chip‐integrated optical sensors is demonstrated. With a simple laser diode, single nanoparticle with radius ≈70 nm is successfully gauged for the first time.
Olefin Oxyamination with Unfunctionalized N‐Alkylanilines
Authors: Gao Shuang , Niggemann Meike 
Published: January 2019

AbstractN‐Alkylanilines have rarely been used in oxyamination reactions, due to the normally necessary pre‐functionalization of the N‐atom. Also, the formation of aminium radical cations (ARCs) of anilines bearing alkyl substituents is plagued by the ARC's tendency to instantaneously convert to α‐amino radicals or iminium ions. We present a readily available reagent combination that addresses both challenges, and thus allows for an oxyamination with N‐alkylanilines via ARCs as the crucial reactive intermediates and excellent diastereoselectivity.magnified image
Transition Metal‐Free Difunctionalization of C−C Bond with Sodium Sulfinates and Water Leading to (E)‐1‐Phenyl‐4‐sulfonylbut‐1‐enes
Authors: Wang Qiao‐Lin , Chen Zan , Zhou Quan , Zhou Cong‐Shan , Xiong Bi‐Quan , Zhang Pan‐Liang , Yang Chang‐An , Liu Yu , Tang Ke‐Wen 
Published: January 2019

AbstractWithout using any transitionmetal and base, an eco‐friendly, practical and economical protocol has been established for the one‐pot synthesis of diverse (E)‐1‐phenyl‐4‐sulfonylbut‐1‐enes from easily accessible starting materials. This strategy features a wide substrate scope, tolerates a broad range of functional groups, employs a less expensive oxidant, is operationally simple, and can be easily scaled‐up.magnified image
Bromoetherification of Alkenyl Alcohols by Aerobic Oxidation of Bromide: Asymmetric Synthesis of 2‐Bromomethyl 5‐Substituted Tetrahydrofurans
Authors: Tomizuka Akihiko , Moriyama Katsuhiko 
Published: January 2019

AbstractAn asymmetric synthesis of 2‐bromomethyl‐5‐substituted tetrahydrofurans via a chiral‐ruthenium‐catalyzed transfer hydrogenation of 3‐butenyl ketones and bromoetherification of chiral pentenyl alcohols was developed. The inhibition of some side reactions furnished the desired products in high yields with high enantioselectivities. In addition, chiral pentenyl alcohols bearing electron‐donating groups triggered substrate racemization in the aerobic bromoetherification.magnified image
Von der Natur inspiriertes Wirkstoffdesign: kristallographische Detektion eines selbstgenerierten Inhibitor‐Grundgerüsts
Authors: Gall Flavio M. , Hohl Deborah , Frasson David , Wermelinger Tobias , Mittl Peer R. E. , Sievers Martin , Riedl Rainer 
Published: January 2019

AbstractDas De‐novo‐Design neuer Wirkstoffmoleküle ist nach wie vor eine anspruchsvolle Aufgabe bei der Suche nach wirksamen und selektiven Modulatoren für therapeutisch relevante Zielproteine. Hier berichten wir über die unerwartete Entdeckung eines peptidischen Liganden 1 durch Röntgenkristallographie, der vom therapeutischen Zielprotein MMP‐13 durch partiellen Selbstabbau generiert wurde, und die anschließende strukturbasierte Optimierung dieses Peptids zu einem hochwirksamen und selektiven β‐Faltblatt‐Peptidmimetikum der endogenen Gewebeinhibitoren von Metalloproteinasen (TIMPs). Der Einbau von nicht‐proteinogenen Aminosäuren in Kombination mit einer Zyklisierungsstrategie erwies sich als entscheidend für das De‐novo‐Design der TIMP‐Peptidmimetika. Das optimierte zyklische Peptid 4 (ZHAWOC7726) ist membrangängig, hat einen IC50‐Wert von 21 nm für MMP‐13 und ein vielversprechendes Selektivitätsprofil bezüglich eines polypharmakologischen Ansatzes mit den Anti‐Krebs‐Zielproteinen MMP‐2 (IC50: 170 nm) und MMP‐9 (IC50: 140 nm).
Synthesis of Benzofuran Derivatives through Cascade Radical Cyclization/Intermolecular Coupling of 2‐Azaallyls
Authors: Deng Guogang , Li Minyan , Yu Kaili , Liu Chunxiang , Liu Zhengfen , Duan Shengzu , Chen Wen , Yang Xiaodong , Zhang Hongbin , Walsh Patrick J. 
Published: January 2019

AbstractBenzofurans are among the most popular structural units in bioactive natural products, however, the synthesis of such structures by radical cyclization cascade reactions is rare. Herein, we report a mild and broadly applicable method for the construction of complex benzofurylethylamine derivatives through a unique radical cyclization cascade mechanism. Single‐electron transfer (SET) from 2‐azaallyl anions to 2‐iodo aryl allenyl ethers initiates a radical cyclization that is followed by intermolecular radical–radical coupling. This expedient approach enables the synthesis of a range of polycyclic benzofurans that would otherwise be difficult to prepare.
Elusive Zintl Ions [μ‐HSi4]3− and [Si5]2− in Liquid Ammonia: Protonation States, Sites, and Bonding Situation Evaluated by NMR and Theory
Authors: Hastreiter Florian , Lorenz Corinna , Hioe Johnny , Gärtner Stefanie , Lokesh Nanjundappa , Korber Nikolaus , Gschwind Ruth M. 
Published: January 2019

AbstractThe existence of [μ‐HSi4]3− in liquid ammonia solutions is confirmed by 1H and 29Si NMR experiments. Both NMR and quantum chemical calculations reveal that the H atom bridges two Si atoms of the [Si4]4− cluster, contrary to the expectation that it is located at one vertex Si of the tetrahedron. The calculations also indicate that in the formation of [μ‐HSi4]3−, protonation is driven by a high charge density and an increase of electron delocalization compared to [Si4]4−. Additionally, [Si5]2− was detected for the first time and characterized by NMR. Calculations show that it is resistant to protonation, owing to a strong charge delocalization, which is significantly reduced upon protonation. Thus, our methods reveal three silicides in liquid ammonia: unprotonated [Si5]2−, terminally protonated [HSi9]3−, and bridge‐protonated [μ‐HSi4]3−. The protonation trend can be roughly predicted by the difference in charge delocalization between the parent compound and the product, which can be finely tuned by the presence of counter ions in solution.
Dynamic Covalent Bonds in Polymeric Materials
Authors: Chakma Progyateg , Konkolewicz Dominik 
Published: January 2019

AbstractDynamic covalent bonds (DCBs) have received significant attention over the past decade. These are covalent bonds that are capable of exchanging or switching between several molecules. Particular focus has recently been on utilizing these DCBs in polymeric materials. Introduction of DCBs into a polymer material provides it with powerful properties including self‐healing, shape‐memory properties, increased toughness, and ability to relax stresses as well as to change from one macromolecular architecture to another. This Minireview summarizes commonly used powerful DCBs formed by simple, often “click” reactions, and highlights the powerful materials that can result. Challenges and potential future developments are also discussed.
Heteroatom‐Doped Porous Carbon Materials with Unprecedented High Volumetric Capacitive Performance
Authors: Jin Huile , Feng Xin , Li Jun , Li Matthew , Xia Yuanzhi , Yuan Yifei , Yang Chao , Dai Bin , Lin Zhiqun , Wang Jichang , Lu Jun , Wang Shun 
Published: January 2019

AbstractThe design of carbon‐based materials with a high mass density and large porosity has always been a challenging goal, since they fulfill the demands of next‐generation supercapacitors and other electrochemical devices. We report a new class of high‐density heteroatom‐doped porous carbon that can be used as an aqueous‐based supercapacitor material. The material was synthesized by an in situ dehalogenation reaction between a halogenated conjugated diene and nitrogen‐containing nucleophiles. Under the given conditions, pyridinium salts can only continue to perform the dehalogenation if there is residue water remaining from the starting materials. The obtained carbon materials are highly doped by various heteroatoms, leading to high densities, abundant multimodal pores, and an excellent volumetric capacitive performance. Porous carbon tri‐doped with nitrogen, phosphorous, and oxygen exhibits a high packing density (2.13 g cm−3) and an exceptional volumetric energy density (36.8 Wh L−1) in alkaline electrolytes, making it competitive to even some Ni‐MH cells.
Readily Available Primary Aminoboranes as Powerful Reagents for Aldimine Synthesis
Authors: Junor Glen P. , Romero Erik A. , Chen Xi , Jazzar Rodolphe , Bertrand Guy 
Published: January 2019

AbstractPrimary aminoboranes (RNHBR2), which are readily available by spontaneous dehydrocoupling of amines and boranes cleanly react at room temperature with aldehydes to give aldimines. The overall transformation from amines to aldimines can be conveniently performed by a sequential one‐pot reaction. This synthetic strategy is especially useful for electron poor and bulky amines which are reluctant to react with aldehydes under dehydration conditions. Using a Glorius robustness screen, we show that this methodology is chemoselective, and functional group tolerant. Computational and experimental data support the irreversible formation of the aldimine product in marked contrast with traditional methods.
Cofactor Controlled Encapsulation of a Rhodium Hydroformylation Catalyst
Authors: Jongkind Lukas J. , Elemans Johannes A. A. W. , Reek Joost N. H. 
Published: January 2019

AbstractSupramolecular approaches in transition‐metal catalysis, including catalyst encapsulation, have attracted considerable attention. Compared to enzymes, supramolecular catalysts in general are less complex. Enzyme activity is often controlled by the use of smaller cofactor molecules, which is important in order to control reactivity in complex mixtures of molecules. Interested in increasing complexity and allowing control over supramolecular catalyst formation in response to external stimuli, we designed a catalytic system that only forms an efficient supramolecular complex when a small cofactor molecule is added to the solution. This in turn affects both the activity and selectivity when applied in a hydroformylation reaction. This contribution shows that catalyst encapsulation can be controlled by the addition of a cofactor, which affects crucial catalyst properties.
Control Mechanism for cis Double‐Bond Formation by Polyunsaturated Fatty‐Acid Synthases
Authors: Hayashi Shohei , Satoh Yasuharu , Ogasawara Yasushi , Maruyama Chitose , Hamano Yoshimitsu , Ujihara Tetsuro , Dairi Tohru 
Published: January 2019

AbstractPolyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) are essential fatty acids for humans. Some microorganisms biosynthesize these PUFAs through PUFA synthases composed of four subunits with multiple catalytic domains. These PUFA synthases each create a specific PUFA without undesirable byproducts, even though the multiple catalytic domains in each large subunit are very similar. However, the detailed biosynthetic pathways and mechanisms for controlling final‐product profiles are still obscure. In this study, the FabA‐type dehydratase domain (DHFabA) in the C‐subunit and the polyketide synthase‐type dehydratase domain (DHPKS) in the B‐subunit of ARA synthase were revealed to be essential for ARA biosynthesis by in vivo gene exchange assays. Furthermore, in vitro analysis with truncated recombinant enzymes and C4‐ to C8‐acyl ACP substrates showed that ARA and EPA synthases utilized two types of DH domains, DHPKS and DHFabA, depending on the carbon‐chain length, to introduce either saturation or cis double bonds to growing acyl chains.
Accordion‐Like Motion in Electrochemically Switchable Crown Ether/Ammonium Oligorotaxanes
Authors: Schröder Hendrik V. , Stein Felix , Wollschläger Jan M. , Sobottka Sebastian , Gaedke Marius , Sarkar Biprajit , Schalley Christoph A. 
Published: January 2019

AbstractReversible oxidation reactions in electrochemically switchable oligorotaxanes with tetrathiafulvalene (TTF) decorated 24‐crown‐8 ether wheels generate intramolecular mixed‐valence and radical‐cation interactions between the wheels. This induces shuttling of the wheels and a contraction of inter‐wheel distances. Further oxidation generates repulsive forces between the TTFs and maximizes the inter‐wheel distances instead. These interactions and co‐conformational changes were not observed for structurally similar controls in which acetyl groups along the axle prevent translational motion of the wheels. This operation mode of oligorotaxanes, which is reminiscent of an accordion‐like motion, is promising for functional materials and nanodevices such as piston‐type rotaxane motors.
Filling and coloring effect of pearl shell powder and dye‐loaded pearl shell powder on polypropylene
Authors: Ge Liuqin , Fan Neng , Zhou Youzhou , Xia Meisheng , Ye Ying 
Published: January 2019

ABSTRACTDye‐loaded shell powder (DPSP), as a novel filler and pigment, was fabricated from pearl shell powder (PSP) and Direct Red 28. PSP (mean diameter of 1.94 μm) and DPSP (mean diameter of 1.62 μm) were individually incorporated into polypropylene (PP), and the mechanical, crystallization, and color properties of PSP/PP and DPSP/PP composites were investigated. As compared to PSP, DPSP exhibited superior reinforcing and toughening effects on PP, due to the ameliorated filler–polymer interfacial interaction. The optimal additive amount of DPSP was determined as 10 wt %, under which the tensile strength of PP was raised from 33.17 to 35.37 MPa, flexural strength from 41.16 to 44.35 MPa, and impact strength from 3.77 to 5.98 kJ/m2. In comparison with PSP/PP, higher content of β‐PP phase was confirmed in DPSP/PP composites. Furthermore, uniform redness distribution was achieved in DPSP/PP specimens, demonstrating the good coloration performance of DPSP. The results indicated that DPSP can be utilized for coloration and filling modification of polymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47455
Synthesis of luminescent polymers in the UV light region from dimethacrylate monomer using novel quinoline dyes
Authors: Alarcon Rafael Turra , dos Santos Giovanny Carvalho , de Oliveira Arthur Rossi , da Silva‐Filho Luiz Carlos , Bannach Gilbert 
Published: January 2019

ABSTRACTThis study aims at thermal and morphological features, as well as the degree of conversion these luminescent polymers obtained using a dimethacrylate monomer, and quinoline dyes as photoinitiator. The photoinitiators provide a fluorescent propriety to the final polymer. Thermal properties such as thermal stability, steps of mass loss, and glass transition are obtained by thermogravimetry‐differential thermal analysis and derivative thermogravimetric and differential scanning calorimetry. Using the mid‐infrared spectroscopy, it is possible to calculate the degree of conversion/rate of polymerization; the data indicate that the quinoline derivatives could be used as photoinitiators in lower concentration (0.1%) resulting in solid rigid polymers with higher conversion (74.24, 71.81, 66.36, and 61.09%). The morphological characteristics of polymers are analyzed by scanning electronic microscopy. Finally, solid ultraviolet–visible (UV–vis) analysis shows a bathochromic shift, due to the stabilization of the molecules in the solid state, compared to liquid UV–vis analysis. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47461.
Comparison of four commonly used high temperature vulcanized silicone rubber formulas for outdoor insulator and their regional adaptability
Authors: Lin Ying , Wang Liming , Yin Fanghui , Farzaneh Masoud , Liu Yuhao , Gao Siming 
Published: January 2019

ABSTRACTHigh temperature vulcanized silicone rubber (HTVSR) insulators are widely used in transmission lines. In this article, four formulas [fumed silica and precipitated silica as reinforcing agent, alumina trihydrate (ATH) and alumina as flame retardant, and Fe2O3and Fe3O4as colorant] widely used in the production of HTVSR insulators were investigated by performing a series of laboratory experiments. The surface morphologies of silicone rubber, mechanical characterization (hardness, tensile property, and tear strength), electrical properties (volume resistivity, dielectric property, and breakdown strength), hydrophobicity and its transfer property, and thermal property of these four formulas were analyzed. According to the test results, the formula composed of fumed silica, Fe2O3colorant, and alumina trihydrate (ATH) were excellent in mechanical properties because of more secondary structures, more bound rubber, and uniform dispersion. Therefore, it can be used in strong wind and bird pecking regions. Due to the absence of crystal water, the formula composed of fumed silica, Fe2O3colorant, and alumina was observed to be excellent in thermal stability and electrical properties, making it suitable for the regions with high temperature and humidity. The formula composed of precipitated silica, Fe3O4colorant, and ATH was found to be excellent in hydrophobicity transfer characteristics because of more raw rubber and satisfactory performance could be expected when it was applied in polluted regions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47477.
Spodoptera litura cyclophilin A is required for Microplitis bicoloratus bracovirus‐induced apoptosis during insect cellular immune response
Authors: Tian Hang‐Yu , Hu Yan , Zhang Pan , Xing Wen‐Xi , Xu Cuixian , Yu Dan , Yang Yang , Luo Kaijun , Li Ming 
Published: January 2019

AbstractMicroplitis bicoloratus bracovirus (MbBV) is a polydnavirus found in the parasitic wasp M. bicoloratus. Although MbBV is a known inducer of apoptosis in host hemocytes, the mechanism by which this occurs remains elusive. In this study, we found that expression of cyclophilin A (CypA) was significantly upregulated in Spodoptera litura hemocytes at 6‐day post‐parasitization. Similar results were reported in High Five cells (Hi5 cells) infected by MbBV, suggesting that the upregulation of CypA is linked to MbBV infection in insect cells. cDNA encoding CypA was cloned from parasitized hemocytes of S. litura, and bioinformatic analyses showed that S. litura CypA belongs to the cyclophilin family of proteins. Overexpression of S. litura CypA in Hi5 cells revealed that the protein promotes MbBV‐induced apoptosis in vitro. Conversely, suppression of the expression and activity of CypA protein significantly rescued the apoptotic phenotype observed in MbBV‐infected Hi5 cells, suggesting that it plays a key role in this process. MbBV infection also promoted the cytoplasmic‐nuclear translocation of CypA in Hi5 cells. Taken together, these results suggest that MbBV infection upregulates the expression of CypA, which is required for MbBV‐mediated apoptosis. Our findings provide insight into the role that CypA plays in insect cellular immune response.
Heberden's Nodes and Knee Osteoarthritis–Related Osseous Structural Damage: Exploratory Study From the Osteoarthritis Initiative
Authors: Haj‐Mirzaian Arya , Mohajer Bahram , Guermazi Ali , Shakoor Delaram , Haugen Ida K. , Roemer Frank W. , Demehri Shadpour 
Published: January 2019

ObjectiveTo explore whether Heberden's nodes (HNs) could predict magnetic resonance imaging (MRI)–based knee osteoarthritis (OA)–related osseous structural progression.MethodsFive hundred seventy‐five subjects from the Foundation for the National Institutes of Health project underwent clinical examination to evaluate HNs at baseline and knee MRI at baseline and 24 months. The MRI was read according to the semiquantitative MRI OA Knee Score and quantitative periarticular bone morphology measures. Adjusted linear/logistic regression models were implemented to assess the association between the presence of HNs at baseline examination and worsening of MRI‐defined osseous structural damage, and odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated.ResultsComparing patients with HNs (n = 395) and patients without HNs (n = 180), more periarticular bone area expansion in the knee joint was seen in the patients with HNs over 24 months (adjusted OR [ORadj] 1.39 [95% CI 1.06, 1.83], corrected P [Pcorr] = 0.019), especially in the medial femur (ORadj 1.49 [95% CI 1.05, 2.13], Pcorr = 0.026) and lateral femur (ORadj 2.51 [95% CI 1.58, 3.97], Pcorr < 0.001), femoral notch (ORadj 1.37 [95% CI 1.02, 1.84], Pcorr = 0.04), and lateral trochlea (ORadj 1.44 [95% CI 1.08, 1.9], Pcorr = 0.012). However, a trend toward less osteophyte worsening was seen in patients with HNs in the whole knee joint (ORadj 0.63 [95% CI 0.40, 1.02], Pcorr = 0.058), particularly in the femur region (ORadj 0.54 [95% CI 0.31, 0.95], Pcorr = 0.03), compared to patients without HNs.ConclusionThe presence of HNs was associated with increased MRI‐based periarticular bone area expansion, but less osteophyte worsening over 24 months in the knee joint, especially in the femoral region.