bluuebunny/crossref_metadata_2025 huggingface dataset:
Atomic Structure of Domain and Interphase Boundaries in Ferroelectric HfO2
Authors: Grimley Everett D. , Schenk Tony , Mikolajick Thomas , Schroeder Uwe , LeBeau James M.
Published: January 2018

Though ferroelectric HfO2 thin films are now well characterized, little is currently known about their grain substructure. In particular, the formation of domain and phase boundaries requires investigation to better understand phase stabilization, switching, and phase interconversion. Here, scanning transmission electron microscopy is applied to investigate the atomic structure of boundaries in these materials. It is found that orthorhombic/orthorhombic domain walls and coherent orthorhombic/monoclinic interphase boundaries form throughout individual grains. The results inform how interphase boundaries can impose strain conditions that may be key to phase stabilization. Moreover, the atomic structure near interphase boundary walls suggests potential for their mobility under bias, which has been speculated to occur in perovskite morphotropic phase boundary systems by mechanisms similar to domain boundary motion.
Facile Synthesis of Nitrogen and Halogen Dual‐Doped Porous Graphene as an Advanced Performance Anode for Lithium‐Ion Batteries
Authors: Liu Huanlong , Tang Yufeng , Zhao Wei , Ding Wei , Xu Jijian , Liang Chenliang , Zhang Zhichao , Lin Tianquan , Huang Fuqiang
Published: January 2018

Nonmetal‐dual doped graphene has attracted considerable attention as high‐performance anode material for lithium‐ion batteries (LIBs) due to the synergistic effects of heteroatom dopants. Herein, nitrogen and halogen (including Cl, Br, and I) dual‐doped graphene is successfully synthesized by a general wet chemical method and lithium storage performance of N, Cl codoped graphene as anode material for LIBs is investigated in detail. The dual‐doped heteroatoms introduce abundant defects and expand the interlayer spacing of graphene to benefit lithium insertion and extraction. When used as a typical anode material, the N and Cl dual‐doped porous graphene reveals a high specific capacity of 1200 mA h g−1 at 0.1 A g−1 and 1010 mA h g−1 at 1.0 A g−1. The as‐prepared sample exhibits superior cycling performance, whose specific capacity remains 95% at 5.0 A g−1 after 1800 cycles. The excellent performance mainly stems from the synergistic effect of structure modification and heteroatom doping, and the capacitive effects are dictated by kinetical analysis. The synthesized nitrogen and halogen dual‐doped porous graphene is a promising anode material for LIBs.
Superlubricity of Graphite Induced by Multiple Transferred Graphene Nanoflakes
Authors: Li Jinjin , Gao Tianyang , Luo Jianbin
Published: January 2018

2D or 3D layered materials, such as graphene, graphite, and molybdenum disulfide, usually exhibit superlubricity properties when sliding occurs between the incommensurate interface lattices. This study reports the superlubricity between graphite and silica under ambient conditions, induced by the formation of multiple transferred graphene nanoflakes on the asperities of silica surfaces after the initial frictional sliding. The friction coefficient can be reduced to as low as 0.0003 with excellent robustness and is independent of the surface roughness, sliding velocities, and rotation angles. The superlubricity mechanism can be attributed to the extremely weak interaction and easy sliding between the transferred graphene nanoflakes and graphite in their incommensurate contact. This finding has important implications for developing approaches to achieve superlubricity of layered materials at the nanoscale by tribointeractions.
Ultraconformable Temporary Tattoo Electrodes for Electrophysiology
Authors: Ferrari Laura M. , Sudha Sudha , Tarantino Sergio , Esposti Roberto , Bolzoni Francesco , Cavallari Paolo , Cipriani Christian , Mattoli Virgilio , Greco Francesco
Published: January 2018

Electrically interfacing the skin for monitoring personal health condition is the basis of skin‐contact electrophysiology. In the clinical practice the use of stiff and bulky pregelled or dry electrodes, in contrast to the soft body tissues, imposes severe restrictions to user comfort and mobility while limiting clinical applications. Here, in this work dry, unperceivable temporary tattoo electrodes are presented. Customized single or multielectrode arrays are readily fabricated by inkjet printing of conducting polymer onto commercial decal transfer paper, which allows for easy transfer on the user's skin. Conformal adhesion to the skin is provided thanks to their ultralow thickness (<1 µm). Tattoo electrode–skin contact impedance is characterized on short‐ (1 h) and long‐term (48 h) and compared with standard pregelled and dry electrodes. The viability in electrophysiology is validated by surface electromyography and electrocardiography recordings on various locations on limbs and face. A novel concept of tattoo as perforable skin‐contact electrode, through which hairs can grow, is demonstrated, thus permitting to envision very long‐term recordings on areas with high hair density. The proposed materials and patterning strategy make this technology amenable for large‐scale production of low‐cost sensing devices.
Mesoscopic 2D Charge Transport in Commonplace PEDOT:PSS Films
Authors: Honma Yuta , Itoh Keisuke , Masunaga Hiroyasu , Fujiwara Akihiko , Nishizaki Terukazu , Iguchi Satoshi , Sasaki Takahiko
Published: January 2018

The correlation between the transport properties and structural degrees of freedom of conducting polymers is a central concern in both practical applications and scientific research. In this study, the existence of mesoscopic 2D coherent charge transport in poly(3,4‐ethylenedioxythiophene):poly‐(styrenesulfonate) (PEDOT:PSS) film is demonstrated by performing structural investigations and high‐field magnetoconductance (MC) measurements in magnetic fields of up to 15 T. The researchers have succeeded in observing marked positive MCs reflecting 2D electronic states in a conventional drop‐cast film. This low‐dimensional feature is surprising, since PEDOT:PSS—a mixture of two different polymers—seems to be significantly different from crystalline 2D materials from the viewpoint of structural inhomogeneity, especially in popular drop‐cast thick films. The results of the structural experiments suggest that such 2D transport originates from the nanometer‐scale self‐assembled laminated structure, which is composed of PEDOT nanocrystals wrapped by insulating sheets consisting of amorphous PSSs. These results indicate that charge transport in the PEDOT:PSS film can be divided into two regimes: mesoscopic 2D coherent tunneling and macroscopic 3D hopping among 2D states. These findings elucidate the hieratical nature of charge transport in the PEDOT:PSS film, which can provide new insight into a recent engineering concern, i.e., the anisotropic conductance.
A regime map for the normal surface impact of wet and dry agglomerates
Authors: Khalilitehrani Mohammad , Olsson Joakim , Rasmuson Anders , Daryosh Farin
Published: January 2018

The normal surface impacts of wet and dry agglomerates are simulated in a discrete element modeling framework. While the impact behavior of dry agglomerates has been addressed previously, similar studies on wet agglomerate impact are missing. By adding a small amount of liquid to a dry agglomerate, the impact behavior changes significantly. The impact behavior of the agglomerates at different moisture contents and impact energies are analyzed through postimpact parameters and coupled to their microscopic and macroscopic properties. While increasing the impact energy breaks more interparticle bonds and intensifies damage and fragmentation, increasing the moisture content is found to provide the agglomerates with higher deformability and resistance against breakage. It is shown that the interplay of the two latter parameters together with the agglomerate structural strength creates various impact scenarios, which are classified into different regimes and addressed with a regime map. © 2018 American Institute of Chemical Engineers AIChE J, 64: 1975–1985, 2018
Der Bindungsmodus eines Tau‐Peptids mit Tubulin
Authors: Kadavath Harindranath , Cabrales Fontela Yunior , Jaremko Mariusz , Jaremko Łukasz , Overkamp Kerstin , Biernat Jacek , Mandelkow Eckhard , Zweckstetter Markus
Published: January 2018

Das Mikrotubuli‐assoziierte Protein Tau fördert die Polymerisation von Tubulin und beeinflusst die Mikrotubuli‐Funktion. Aufgrund einer inhärenten Flexibilität in der Tau‐Tubulin‐Wechselwirkung sind die strukturellen Grundlagen dieser Interaktion weitestgehend unbekannt. Mithilfe von Liganden‐Rezeptor‐spezifischen NMR‐Methoden und positionsspezifischer Mutagenese wird nachgewiesen, dass die Region N‐terminal zu den vier Mikrotubuli‐bindenden Wiederholungssequenzen an die Oberfläche von α‐Tubulin bindet. Der Bindungsprozess ist komplex, umfasst eine partielle Kupplung verschiedener Tau‐Aminosäuren und wird durch Tau‐Phosphorylierung an Y394 und S396 beeinflusst. Die Untersuchungen stärken die Hypothese einer engen Verbindung zwischen Tau‐Phosphorylierung und ‐Bindung an Tubulin. Ferner unterstreichen die Ergebnisse die Stärke der INPHARMA‐NMR‐Methode für die Analyse von Wechselwirkungen zwischen intrinsisch ungeordneten Peptiden/Proteinen und ihren molekularen Partnern.
Palladium‐Catalyzed Enantioselective Desymmetrizing Aza‐Wacker Reaction: Development and Application to the Total Synthesis of (−)‐Mesembrane and (+)‐Crinane
Authors: Bao Xu , Wang Qian , Zhu Jieping
Published: January 2018

Reported is an unprecedented catalytic enantioselective desymmetrizing aza‐Wacker reaction. In the presence of a catalytic amount of a newly developed Pd(CPA)2(MeCN)2 catalyst (CPA=chiral phosphoric acid), a pyrox ligand, and molecular oxygen, cyclization of properly functionalized prochiral 3,3‐disubstituted cyclohexa‐1,4‐dienes afforded enantioenriched cis‐3a‐substituted tetrahydroindoles in good yields with excellent enantioselectivities. A cooperative effect between the phosphoric acid and the pyrox ligand ensured efficient transformation. This reaction was tailor‐made for Amaryllidaceae and Sceletium alkaloids as illustrated by its application in the development of the concise and divergent total synthesis of (−)‐mesembrane and (+)‐crinane.
Multiple Binding Sites Contribute to the Mechanism of Mixed Agonistic and Positive Allosteric Modulators of the Cannabinoid CB1 Receptor
Authors: Saleh Noureldin , Hucke Oliver , Kramer Gert , Schmidt Esther , Montel Florian , Lipinski Radoslaw , Ferger Boris , Clark Timothy , Hildebrand Peter W. , Tautermann Christofer S.
Published: January 2018

The cannabinoid CB1 receptor (CB1R) is an abundant metabotropic G‐protein‐coupled receptor that has been difficult to address therapeutically because of CNS side effects exerted by orthosteric drug candidates. Recent efforts have focused on developing allosteric modulators that target CB1R. Compounds from the recently discovered class of mixed agonistic and positive allosteric modulators (Ago‐PAMs) based on 2‐phenylindoles have shown promising functional and binding properties as CB1R ligands. Here, we identify binding modes of both the CP 55,940 agonist and GAT228, a 2‐phenylindole allosteric modulator, by using our metadynamics simulation protocol, and quantify their affinity and cooperativity by atomistic simulations. We demonstrate the involvement of multiple adjunct binding sites in the Ago‐PAM characteristics of the 2‐phenylindole modulators and explain their ability to compete with orthosteric agonists at higher concentrations. We validate these results experimentally by showing the contribution of multiple sites on the allosteric binding of ZCZ011, another homologous member of the class, together with the orthosteric agonist.
RuBisCO‐Inspired CO2 Activation and Transformation by an Iridium(I) Complex
Authors: Langer Jens , Hamza Andrea , Pápai Imre
Published: January 2018

The synthesis of a new iridium(I) complex containing an enamido phosphine anion (dbuP−) and its unique reactivity with CO2 is reported. The complex binds two equivalents of CO2 and initiates a highly selective reaction cascade. The reaction leads to the reversible cleavage of CO2 and the enamido ligand as well. Computational analysis points to the existence of a relatively stable Ir‐CO2 complex as a reaction intermediate prior to CO2 cleavage, which was confirmed experimentally. The observed transformation resembles several aspects of enzymatic CO2 fixation by RuBisCO.
Sustainability assessment of combined steam and dry reforming versus tri‐reforming of methane for syngas production
Authors: Chen Liwen , Gangadharan Preeti , Lou Helen H.
Published: January 2018

Synthesis gas (syngas) is a versatile intermediate in the production of valuable chemicals and fuel, such as methanol, dimethyl ether, ethylene, propylene, and the Fischer–Tropsch fuel. Combining steam reforming and dry reforming (SR + DR) routes can produce syngas with a suitable H2:CO molar ratio (around 2:1) for Fischer–Tropsch synthesis. The newly proposed tri‐reforming (TR) route at experimental scale was a capable alternative to produce syngas in a single reformer with potential benefits such as energy savings and waste flue gas utilization. In this paper, sustainability assessment of SR + DR and TR routes adopting quantifiable indices in economic, environmental, and safety dimensions at industrial scale is performed based on process simulation models. Results show that TR route outperforms SR + DR route in all 3 dimensions. Sensitivity analysis of natural gas price fluctuation does not alter the conclusion. A sustainable root cause analysis is also applied on the SR + DR which identifies root causes affecting its sustainability with the aid of visualization tools such as Pareto chart and fish bone diagram.
Preparation and electrochemical properties of polyaniline/reduced graphene oxide composites
Authors: Li Yunlong , Zheng Yuying
Published: January 2018

Polyaniline (PANI)/reduced graphene oxide (rGO) composites were synthesized by in situ oxidative polymerization of aniline on reduced graphene sheets. Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, transmission electron microscopy, and scanning electron microscopy were used to characterize the composites. The results indicated PANI/rGO composites were produced and contained covalent bonds between the functional groups of PANI and rGO. A uniform coating of PANI on the rGO sheets had a synergistic effect on the properties of the composites. The electrochemical properties of the PANI/rGO composites produced using different feed ratios of aniline to rGO were studied. The results showed that the composites exhibited a maximum specific capacitance of 797.5 F/g at 0.5 A/g and minimum charge transfer resistance of 0.98 Ω when the feed ratio of aniline to rGO was 2:1. These values were superior to those of pure PANI and rGO. The composites also displayed excellent cycling stability, with specific capacitance retention of 92.43% after 1000 cycles. These stable structural composites show promise for the development of new supercapacitor applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46103.
Effect of polyurethane sizing on carbon fibers surface and interfacial adhesion of fiber/polyamide 6 composites
Authors: Zhang Tao , Zhao Yueqing , Li Hongfu , Zhang Boming
Published: January 2018

Commercial epoxy sized carbon fibers (CFs) or unsized CFs have poor interfacial adhesion with polyamide 6 (PA6). Here, CFs are coated with polyurethane (PU) and their surface properties in terms of surface chemistry, contact angle, roughness, and morphology, are investigated. The results of Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy demonstrate PU sizing evidently increases the quantity of polar functional groups on the CFs surface. The surface energy of the PU sized fiber is calculated according to the Owens–Wendt method. Compared with unsized fibers, the contact angle of PU sized fibers is decreased while their total surface energy is increased, indicating superior wettability. Moreover, transverse fiber bundle tests are performed to determine the interfacial adhesion between the CFs and PA6 matrix. The transverse fiber bundle strength of unsized CF is measured to be 12.57 MPa. For PU sized CFs processed with sizing concentration of 1.2%, this value is increased to 24.35 MPa, showing an increase of more than 90%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46111.
Preparation of a novel styrene copolymer: Simultaneously improving the thermal stability and toughness
Authors: Cui Jianguang , Zhu Changjiang , He Mingshan , Ke Zhenkun , Liu Yu , Tai Qilong , Xiao Xifu , Hu Yuan
Published: January 2018

In order to improve the flame retardancy of polystyrene, a phosphorus‐ and nitrogen‐containing monomer, N,N‐tetramethyl‐bis(phospohonate)‐2‐hydroxyethyl bis(methylene) amine acrylate (BC2NP2), was synthesized and characterized, and then incorporated into various amounts of polystyrene via radical emulsion copolymerization. The copolymers prepared were characterized by Fourier transform infrared, nuclear magnetic resonance spectra, transmission electron microscopy, differential scanning calorimetry, thermalgravimetric analysis, microscale combustion calorimeter, dynamic mechanical analysis, and impact tests. The results showed that all the copolymers had well spherical core–shell structure. Notably, despite a few amounts of the BC2NP2 units in copolymers, all the copolymers exhibited significantly enhanced thermal stability, decreased glass transition temperature, and reduced flammability. Furthermore, from dynamic mechanical analysis and impact tests, it was observed the storage modulus was decreased and the impact strength had a certain degree of improvement with the incorporation of commoner. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46120.
Effects of Streptomycin Administration on Increases in Skeletal Muscle Fiber Permeability and Size Following Eccentric Muscle Contractions
Authors: Hayao Keishi , Tamaki Hiroyuki , Nakagawa Kouki , Tamakoshi Keigo , Takahashi Hideaki , Yotani Kengo , Ogita Futoshi , Yamamoto Noriaki , Onishi Hideaki
Published: January 2018

The purpose of this study was to investigate the preventive effect of streptomycin (Str) administration on changes in membrane permeability and the histomorphological characteristics of damaged muscle fibers following eccentric contraction (ECC ). Eighteen 7‐week‐old male Fischer 344 rats were randomly assigned to three groups: control (Cont), ECC, and ECC with Str (ECC + Str). The tibialis anterior (TA) muscles in both ECC groups were stimulated electrically and exhibited ECC. Evans blue dye (EBD), a marker of muscle fiber damage associated with increased membrane permeability, was injected 24 hr before TA muscle sampling. The number of EBD‐positive fibers, muscle fiber cross‐sectional area (CSA), and roundness were determined via histomorphological analysis. The ECC intervention resulted in an increased fraction of EBD‐positive fibers, a larger CSA, and decreased roundness. The fraction of EBD‐positive fibers was 79% lower in the ECC + Str group than in the ECC group. However, there was no difference in the CSA and roundness of the EBD‐positive fibers between the two ECC groups. These results suggest that Str administration can reduce the number of myofibers that increase membrane permeability following ECC, but does not ameliorate the extent of fiber swelling in extant EBD‐positive fibers. Anat Rec, 301:1096–1102, 2018. © 2018 Wiley Periodicals, Inc.
Histological Changes in Alveolar Bone After Onlay Augmentation Using the Casing Method
Authors: Maruyama Kiichi , Ogiso Makoto , Mineno Seiji , Ono Wataru , Izumi Yuichi
Published: January 2018

Numerous studies on alveolar bone augmentation have been reported. However, it remains challenging to obtain favorable new bone, especially for onlay bone augmentation. For successful onlay bone augmentation, it is necessary to use a graft material with high bone‐forming activity and wound stabilization. We performed onlay bone augmentation on the buccal surface of mandibular alveolar bone in dogs, using a polyethylene terephthalate (PET) case (Casing method). The aim of this study was to histologically examine the feasibility of Casing method for external onlay bone augmentation. Beagle dogs were selected for this study. At 12 weeks after tooth extraction, a PET case was placed on the buccal surface of mandibular alveolar bone and filled with a mixture of hydroxyapatite and β‐tricalcium phosphate (β‐TCP) particles (volume ratio 1:1) impregnated with crushed autogenous bone (superfine bone powder) suspended in plasma. At 4, 8, and 16 weeks after bone graft, nondecalcified sections were histologically examined. At 4 weeks, new bone formation on the particle surfaces was observed on the original bone side of the PET case. At 16 weeks, bone formation was observed in almost all areas inside the case. The percentage of the augmented area (including new bone and particles surrounded by new bone; was significantly greater at 16 weeks (85.7% ± 6.0%) than at 4 weeks (10.5% ± 4.8%) or 8 weeks (69.6% ± 15.6%). The results of this study suggest that onlay bone augmentation using the Casing method has considerable potential to yield histologically favorable new bone formation. Anat Rec, 301:1148–1158, 2018. © 2018 Wiley Periodicals, Inc.
A Cross‐coupling Control Approach for Coordinated Formation of Surface Vessels with Uncertain Disturbances
Authors: Fu Mingyu , Yu Lingling , Wang Yuanhui , Jiao Jianfang
Published: January 2018

In this paper, a cross‐coupling control approach for the coordinated formation of multiple marine surface vessels with direct communication topology in the presence of model uncertainties and external disturbances is presented. To synchronize the vessels' relative position errors while tracking their assigned trajectories, a cross‐coupling formation controller is designed, in which a sliding mode surface in terms of the velocity tracking error and position cross‐coupling error is introduced. Then, an adaptive radial basis function neural network is incorporated into the controller to learn the upper bound of model uncertainties and external disturbances. Utilizing Barbalat's lemma and topology theory, all of the error signals in the closed‐loop system are proved to converge to zero asymptotically. Finally, numerical simulation results are provided to demonstrate the effectiveness of the proposed coordinated formation control strategy.
Fabrication of silver chloride nanoparticles using a plant serine protease in combination with photoactivation and investigation of their biological activities
Authors: Siritapetawee Jaruwan , Limphirat Wanwisa , Nantapong Nawarat , Songthamwat Dujdow
Published: January 2018

Recently, the development of "green" methods for fabrication of silver nanoparticles (Ag‐NPs) has been emphasized, in view of their environmental safety, feasibility, and low cost. In this study, a serine protease, EuP‐82 from Euphorbia cf. lactea latex, was used to fabricate silver chloride nanoparticles (AgCl‐NPs) in phosphate‐buffered saline (pH 7.2), under the influence of visible light. The fabricated nanoparticles had a maximal surface plasmon resonance absorption peak at 435 nm. The size of the AgCl‐NPs, estimated by scanning electron microscopy, was 57 ± 14.7 nm. Energy dispersive X‐ray spectroscopy, X‐ray absorption spectroscopy, and X‐ray diffraction analysis confirmed that the fabricated Ag‐NPs were of the AgCl type. The fabricated nanoparticles had antioxidant activity, scavenging DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) radicals with IC50 of 204 ± 1.8 μg/mL. The fabricated AgCl‐NPs had broad‐spectrum in vitro antimicrobial activities, acting against the Gram‐positive bacteria Staphylococcus aureus, methicillin‐resistant S. aureus (MRSA), and Bacillus cereus, and the Gram‐negative bacteria Escherichia coli and Pseudomonas aeruginosa. AgCl‐NPs also showed antifungal activity against Candida albicans and C. tropicalis. In addition, AgCl‐NPs showed antiprotozoal activity against Giardia lamblia, with IC50 202 ± 2.1 μg/mL. Based on the biological activities of the fabricated AgCl‐NPs, they have the potential for widespread application in medicine and industry.
Rechnerische und experimentelle Bestimmung der Tragfähigkeit eines Fensterbefestigers
Authors: Becker Rainer , Scheller Eckehard , Küenzlen Jürgen
Published: January 2018

Die Fenstermontage in Mauerwerk, insbesondere in Lochsteinen mit dünnen Stegen und/oder Dämmstoff‐Füllungen, ist in den vergangenen Jahren zu einer anspruchsvollen Aufgabe geworden, für die eine vorherige statische Bemessung empfohlen wird. Für die Bemessung eines modernen Fensterbefestigers wurde ein auf Versuchen basierendes Rechenmodell entwickelt, auf deren Grundlage eine Zulassung erteilt wurde.
DQAsomes Nanoparticles Promote Osteogenic Differentiation of Human Adipose‐derived Mesenchymal Stem Cells
Authors: Bae Yoonhee , Jung Min Kyo , Mun Ji Young , Mallick Sudipta , Song Su Jeong , Kim Dong Min , Ko Kyung Soo , Han Jin , Choi Joon Sig
Published: January 2018

Mesenchymal stem cells (MSCs) can self‐renew and differentiate into multiple cell types. The delivery of drugs to MSCs is an important tool in the emerging fields of tissue regeneration and engineering. In this study, we determined the anticancer efficiency of DQAsomes, which displayed affinity toward human adipose‐derived mesenchymal stem cells (AD‐MSCs). Cytotoxicity assays were conducted to examine human AD‐MSCs. We also evaluated the cellular effects of human AD‐MSCs treated with DQAsomes by cell cycle distribution analysis, annexin‐V propidium iodide staining, and H2DCFDA and found that DQAsomes promoted the differentiation of AD‐MSCs into osteoblast cells. Furthermore, flow cytometry analysis revealed that human AD‐MSCs treated with DQAsomes maintained the phenotypic characteristics of human AD‐MSCs. We demonstrated that DQAsomes can be used in tissue engineering and have clinical relevance as effective drug and protein delivery systems.
Transubclavian approach: A competitive access for transcatheter aortic valve implantation as compared to transfemoral
Authors: Amat‐Santos Ignacio J. , Rojas Paol , Gutiérrez Hipólito , Vera Silvio , Castrodeza Javier , Tobar Javier , Goncalves‐Ramirez L. Renier , Carrasco Manuel , Catala Pablo , San Román José A.
Published: January 2018

Aims

Empirically, transfemoral (TF) approach is the first choice for transcatheter aortic valve implantation (TAVI). We aimed to investigate whether transubclavian (TSc) and TF approaches present comparable major outcomes according to current evidence.

Methods

We systematically searched PubMed, EMBASE, and Cochrane database for studies with symptomatic aortic stenosis patients who underwent TAVI through TF or TSc/axillary access from January/2006 to January/2017. Searched terms were: (“aortic stenosis” OR “transcatheter aortic” OR “TAVI” OR “TAVR”) and (“transfemoral” OR “transaxillary” OR “transubclavian”). Major outcomes according to Valve Academic Research Consortium‐2 criteria were gathered. The odds ratio (OR) was used as a summary statistic. A random‐effects model was used. A fully percutaneous TSc TAVI case from our institution illustrates minimalist approach.

Results

Final analysis was made with six studies including 4,504 patients (3,886 TF and 618 TSc). Baseline characteristics of compared groups in individual studies were similar, with the exception of a higher logistic EuroSCORE in the TSc group (23.7 ± 1.92 vs. 21.17 ± 3.51, P = 0.04) and higher prevalence of coronary and peripheral artery disease with OR = 0.67 [95% CI: 0.54–0.83] (P = 0.0003) and OR = 0.08 [95% CI: 0.05–0.12] (P < 0.00001), respectively. TSc group presented comparable 30‐day mortality (OR = 1.37; [95%CI: 0.85–2.21]; P = 0.20). There were no differences for procedural success, 30‐day stroke rate, need for new pacemaker implantation, major vascular complications, and acute kidney injury requiring dialysis. Also, no differences were found concerning 1‐year mortality.

Conclusions

Our study suggests that TSc approach may be, not only an alternative route to TF approach for TAVI, but even a competitive one in certain patients with increased risk of femoral injury.
Palladium‐Loaded Cucurbit[7]uril‐Modified Iron Oxide Nanoparticles for C−C Cross‐Coupling Reactions
Authors: Benyettou Farah , Motte Laurence , Traboulsi Hassan , Mazher Javed , Pasricha Renu , Olsen John‐Carl , Trabolsi Ali , Guenin Erwan
Published: January 2018

Cucurbit[7]uril modified iron oxide nanoparticles (CB[7]NPs) were loaded with palladium to form nano‐catalysts (Pd@CB[7]NPs) that, with microwave heating, catalysed Suzuki–Miyaura, Sonogashira, and Mizoroki–Heck cross‐coupling reactions. Reactions were run in environmentally benign 1:1 ethanol/water solvent under convenient aerobic conditions. In a preliminary screening, conversions and yields were uniformly high with turn over frequencies (TOF) ranging from 64 to 7360 h−1. The nano‐catalysts could be recovered with a magnet and reused several times (6 times for Suzuki–Miayura reaction) without loss of activity.
Spectroscopic Studies on Photoinduced Reactions of the Anticancer Prodrug, trans,trans,trans‐[Pt(N3)2(OH)2(py)2]
Authors: Vernooij Robbin R. , Joshi Tanmaya , Horbury Michael D. , Graham Bim , Izgorodina Ekaterina I. , Stavros Vasilios G. , Sadler Peter J. , Spiccia Leone , Wood Bayden R.
Published: January 2018

The photodecomposition mechanism of trans,trans,trans‐[Pt(N3)2(OH)2(py)2] (1, py=pyridine), an anticancer prodrug candidate, was probed using complementary Attenuated Total Reflection Fourier Transform Infrared (ATR‐FTIR), transient electronic absorption, and UV/Vis spectroscopy. Data fitting using Principal Component Analysis (PCA) and Multi‐Curve Resolution Alternating Least Squares, suggests the formation of a trans‐[Pt(N3)(py)2(OH/H2O)] intermediate and trans‐[Pt(py)2(OH/H2O)2] as the final product upon 420 nm irradiation of 1 in water. Rapid disappearance of the hydroxido ligand stretching vibration upon irradiation is correlated with a −10 cm−1 shift to the antisymmetric azido vibration, suggesting a possible second intermediate. Experimental proof of subsequent dissociation of azido ligands from platinum is presented, in which at least one hydroxyl radical is formed in the reduction of PtIV to PtII. Additionally, the photoinduced reaction of 1 with the nucleotide 5′‐guanosine monophosphate (5′‐GMP) was comprehensively studied, and the identity of key photoproducts was assigned with the help of ATR‐FTIR spectroscopy, mass spectrometry, and density functional theory calculations. The identification of marker bands for some of these photoproducts (e.g., trans‐[Pt(N3)(py)2(5′‐GMP)] and trans‐[Pt(py)2(5′‐GMP)2]) will aid elucidation of the chemical and biological mechanism of anticancer action of 1. In general, these studies demonstrate the potential of vibrational spectroscopic techniques as promising tools for studying such metal complexes.
Olefin‐Stabilized Cobalt Nanoparticles for C=C, C=O, and C=N Hydrogenations
Authors: Sandl Sebastian , Schwarzhuber Felix , Pöllath Simon , Zweck Josef , Jacobi von Wangelin Axel
Published: January 2018

The development of cobalt catalysts that combine easy accessibility and high selectivity constitutes a promising approach to the replacement of noble‐metal catalysts in hydrogenation reactions. This report introduces a user‐friendly protocol that avoids complex ligands, hazardous reductants, special reaction conditions, and the formation of highly unstable pre‐catalysts. Reduction of CoBr2 with LiEt3BH in the presence of alkenes led to the formation of hydrogenation catalysts that effected clean conversions of alkenes, carbonyls, imines, and heteroarenes at mild conditions (3 mol % cat., 2–10 bar H2, 20–80 °C). Poisoning studies and nanoparticle characterization by TEM, EDX, and DLS supported the notion of a heterotopic catalysis mechanism.
Luminescence Thermochromism of Gold(I) Phosphane–Iodide Complexes: A Rule or an Exception?
Authors: Glebko Nina , Dau Thuy Minh , Melnikov Alexei S. , Grachova Elena V. , Solovyev Igor V. , Belyaev Andrey , Karttunen Antti J. , Koshevoy Igor O.
Published: January 2018

A series of gold(I) iodide complexes 1–11 have been prepared from di‐, tri‐, and tetraphosphane ligands. Crystallographic studies reveal that the di‐ (1–7) and tetrametallic (11) compounds feature linearly coordinated gold(I) ions with short aurophilic contacts. Their luminescence behavior is determined by the combined influence of the phosphane properties, metal–metal interaction, and intermolecular lattice‐defined interactions. The proposed variable contribution of 3(X+M)‐centered (X=halogen; M=metal) and 3XLCT (halogen to ligand charge transfer) electronic transitions into the lowest lying excited state, which is influenced by supramolecular packing, is presumably responsible for the alteration of room‐temperature emission color from green (λ=545 nm, for 11) to near‐IR (λ=698 nm, for 2). Dinuclear compounds 6 and 7 exhibit distinct luminescence thermochromism with a blueshift up to 5750 cm−1 upon cooling. Such dramatic change of emission energy is assigned to the presence of two coupled triplet excited states of 3ππ* and 3(X+M)C/3XLCT nature, the presence of which depends on both molecular structure and the crystal lattice arrangement.
Resveratrol Radical Repair by Vitamin C at the Micelle–Water Interface: Unexpected Reaction Rates Explained by Ion–Dipole Interactions
Authors: Kerzig Christoph , Hoffmann Matthias , Goez Martin
Published: January 2018

Repair reactions of lipophilic phenoxy radicals by hydrophilic co‐antioxidants at model membranes are important for understanding the factors that govern the interactions between radical scavengers in biological systems. By using near‐UV photoionization, we have selectively generated the phenoxy radical of the famous antioxidant resveratrol inside anionic (SDS), cationic (DTAC), or neutral (TX‐100) micelles, as well as in homogeneous aqueous solution, and have compared its repairs in these media by the water‐soluble co‐antioxidants ascorbic acid and ascorbate monoanion. With all surfactants, these reactions are dynamic processes at the micelle–water interface. Whereas for the combinations ascorbate monoanion/ ionic micelle the repair rates can be rationalized by the Coulombic interactions, unexpected effects were observed with the neutral ascorbic acid and the charged micelles: for the anionic micelles, this repair is three times faster than in homogeneous solution, and two orders of magnitude faster than for the cationic micelles. Given that the repair by a concerted proton–electron transfer demands a coplanar arrangement of the resveratrol phenoxy centre sticking out into the Stern layer and the co‐antioxidant hydroxy moiety approaching from the aqueous bulk, we explain these results by ion–dipole interactions: only at a negatively charged micellar surface does the direction of the large dipole moment of ascorbic acid lead to an orientation favourable for the repair.
Infrared Multiphoton Dissociation Spectroscopy with Free‐Electron Lasers: On the Road from Small Molecules to Biomolecules
Authors: Jašíková Lucie , Roithová Jana
Published: January 2018

Infrared multiphoton dissociation (IRMPD) spectroscopy is commonly used to determine the structure of isolated, mass‐selected ions in the gas phase. This method has been widely used since it became available at free‐electron laser (FEL) user facilities. Thus, in this Minireview, we examine the use of IRMPD/FEL spectroscopy for investigating ions derived from small molecules, metal complexes, organometallic compounds and biorelevant ions. Furthermore, we outline new applications of IRMPD spectroscopy to study biomolecules.
Synthesis of PEGylated Semiconducting Polymer Amphiphiles for Molecular Photoacoustic Imaging and Guided Therapy
Authors: Xie Chen , Cheng Penghui , Pu Kanyi
Published: January 2018

Semiconducting polymer nanoparticles (SPNs) have been used as a new class of photonic materials with great potential in biomedical applications, but their synthetic method is limited to nanoprecipitation. Semiconducting polymer amphiphiles (SPAs) that can spontaneously self‐assemble into nanoparticles are ideal alternatives for SPNs. Depending on their backbone structures, SPAs with different optical properties can be developed into nanoprobes for molecular imaging applications such as photoacoustic (PA) and fluorescence imaging as well as photothermal therapy. In this Concept, recent studies on the synthesis of SPAs for PA imaging and guided cancer therapy are summarized. The effect of grafting density on the optical properties of SPAs is discussed, and the nanoparticle sizes of SPAs can be reduced by utilization of a short semiconducting oligomer. Moreover, SPAs can be developed into PA theranostic platform and activatable PA nanoprobes. These studies demonstrate that SPAs are promising for advanced molecular imaging and therapy applications.
Preparation of Chiral Contiguous Epoxyaziridines and Their Regioselective Ring‐Opening for Drug Syntheses
Authors: Mao Hui , Jeong Hyeonsu , Yang Jieun , Ha Hyun‐Joon , Yang Jung Woon
Published: January 2018

Synthetically valuable chiral (aziridin‐2‐yl)oxirane‐3‐carbaldehydes bearing three consecutive functional groups including aziridine, epoxide, and aldehyde were prepared from the stereoselective epoxidation of (aziridin‐2‐yl)acrylaldehydes with H2O2 using organocatalyst (2R)‐ or (2S)‐[diphenyl(trimethylsilyloxy)methyl]pyrrolidine as organocatalyst. The regioselective ring opening of aziridines and epoxides enabled us to achieve the highly efficient asymmetric synthesis of the antibiotic edeine D fragment 3‐hydroxy‐4,5‐diaminopenatanoic acid, an intermediate for the formal synthesis of non‐proteinogenic amino acid (−)‐galantinic acid, and for potent antifungal agent (+)‐preussin, and the medicinally important framework 3‐hydroxy‐2‐hydroxymethylpyrrolidine.
Kinetics of the esterification between lactic acid and isoamyl alcohol in the presence of silica gel‐supported sodium hydrogen sulphate
Authors: Jiang Zhongkai , Xu Jumei , Zeng Zuoxiang , Xue Weilan , Li Shating
Published: January 2018

The esterification reaction between isoamyl alcohol and lactic acid was studied over silica gel‐supported sodium hydrogen sulphate (NaHSO4 · Silica). The influences of the external mass transfer, internal mass transfer, reaction temperature, catalyst loading, and initial reactant molar ratio were investigated. Kinetic experimental data of this esterification reaction obtained at different temperatures (343–378 K) were correlated with three models (the pseudo‐homogeneous (PH), Eley‐Rideal (ER), and Langmuir‐Hinshelwood (LH) model). The UNIFAC method was employed to estimate the activity coefficients when the non‐ideal thermodynamic behaviour of the reaction mixture was considered. The results show that the ER model is more appropriate for predicting the dynamic data of an esterification reaction. It was found that water and isoamyl alcohol were more strongly adsorbed onto the surface of NaHSO4 · Silica than lactic acid and isoamyl lactate, by comparing the adsorption equilibrium constants of different components existing in the reaction. The activation energy and standard enthalpy of the reaction were found to be 54.1 and −6.27 kJ mol−1, respectively.
Endocrine dysfunction induced by immune checkpoint inhibitors: Practical recommendations for diagnosis and clinical management
Authors: Barroso‐Sousa Romualdo , Ott Patrick A. , Hodi F. Stephen , Kaiser Ursula B. , Tolaney Sara M. , Min Le
Published: January 2018

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy. However, because ICIs block coinhibitory molecules on T cells and other immune cells, unleashing them to mediate tumor cell killing, they also can disrupt the maintenance of immunological tolerance to self‐antigens. Compared with chemotherapy, ICIs have a different toxicity profile, especially the occurrence of autoimmune‐like manifestations against multiple organ systems, including endocrine glands, commonly referred to as immune‐related adverse events. The aim of this review was to provide practical recommendations regarding the proper assessment and clinical management related to the new onset of endocrinopathies after the use of ICIs in patients with cancer. Cancer 2018;124:1111‐21. © 2018 American Cancer Society.
Mapping the distribution of language related genes FoxP1, FoxP2, and CntnaP2 in the brains of vocal learning bat species
Authors: Rodenas‐Cuadrado Pedro M. , Mengede Janine , Baas Laura , Devanna Paolo , Schmid Tobias A. , Yartsev Michael , Firzlaff Uwe , Vernes Sonja C.
Published: January 2018

Genes including FOXP2, FOXP1, and CNTNAP2, have been implicated in human speech and language phenotypes, pointing to a role in the development of normal language‐related circuitry in the brain. Although speech and language are unique to humans a comparative approach is possible by addressing language‐relevant traits in animal systems. One such trait, vocal learning, represents an essential component of human spoken language, and is shared by cetaceans, pinnipeds, elephants, some birds and bats. Given their vocal learning abilities, gregarious nature, and reliance on vocalizations for social communication and navigation, bats represent an intriguing mammalian system in which to explore language‐relevant genes. We used immunohistochemistry to detail the distribution of FoxP2, FoxP1, and Cntnap2 proteins, accompanied by detailed cytoarchitectural histology in the brains of two vocal learning bat species; Phyllostomus discolor and Rousettus aegyptiacus. We show widespread expression of these genes, similar to what has been previously observed in other species, including humans. A striking difference was observed in the adult P. discolor bat, which showed low levels of FoxP2 expression in the cortex that contrasted with patterns found in rodents and nonhuman primates. We created an online, open‐access database within which all data can be browsed, searched, and high resolution images viewed to single cell resolution. The data presented herein reveal regions of interest in the bat brain and provide new opportunities to address the role of these language‐related genes in complex vocal‐motor and vocal learning behaviors in a mammalian model system.
SnO2Based Catalysts with Low‐Temperature Performance for Oxidative Coupling of Methane: Insight into the Promotional Effects of Alkali‐Metal Oxides
Authors: Peng Liang , Xu Junwei , Fang Xiuzhong , Liu Wenming , Xu Xianglan , Liu Liang , Li Zhongchen , Peng Honggen , Zheng Renyang , Wang Xiang
Published: January 2018

To develop reactive catalysts for oxidative coupling of methane at low temperatures, different alkali‐metal oxides are adopted in this study to modify the surface of SnO2. In comparison with the unmodified SnO2, the reaction performance of all of the modified catalysts can be significantly improved, among which lithium oxide shows the best promotional effects, and the optimal catalyst is achieved with a Sn/Li molar ratio of 5:5. With this catalyst, the highest C2product yield of 16 % is achieved at 750 °C. The XPS and CO2‐TPD results reveal that for those catalysts with evident enhanced OCM reaction performance, the coexistence of a suitable amount of surface alkaline and electrophilic oxygen sites is indispensable. Furthermore, with the catalysts modified by different amounts of lithium oxide, the C2yield at different temperatures is nearly proportional to the amounts of both surface intermediate alkaline sites and electrophilic oxygen species. Therefore, it is concluded that the abundance and the concerted interaction of these two types of surface active sites are the major factors determining the reaction performance of the SnO2based catalysts. Last, but not least, the optimized catalyst, which has a Sn/Li molar ratio of 5:5 and also contains equal amounts of SnO2and Li2SnO3crystalline phases, exhibits much better reaction performance than Mn/Na2WO4/SiO2, the most promising catalyst at present, in the low‐temperature region (below 750 °C). After all, this may give people some new insight into developing new types of OCM catalysts that can operate at low temperatures and thereby facilitate the industrialization process of this important chemical engineering reaction.
Asymmetric Sulfinylations ofN‐Methylephedrine‐Modified Tri‐ or Tetraalkyl Zincates by Symmetric Diaryl Sulfoxides
Authors: Ruppenthal Simon , Brückner Reinhard
Published: January 2018

Diethylzinc was treated with 1 or 2 equiv. of AlkMgCl or PhMgBr (preferably) or with 1 equiv. ofnBuLi (less efficiently) for forming species – plausibly zincates – which were sulfinylated by diaryl sulfoxides to give racemic alkyl aryl sulfoxides in yields reaching 100 %. Dialkylzinc reagents were also activated by treatments with 1 or 2 equiv. of an enantiomerically pure alkylmagnesium β‐aminoalkoxide. This worked best when the alkoxide stemmed from a dialkylmagnesium reagent and an equimolar amount ofN‐methyl‐(–)‐ephedrine. This second activation mode allowed sulfinylations of what was originally the dialkylzinc reagent with diaryl sulfoxides. This generated alkyl aryl sulfoxides with enantiomeric ratios up to 93:7 in up to 100 % yield.
A One‐Pot Cascade Reaction by Combining NH‐Sulfoximines with Thiophenols Under Mild Conditions
Authors: Peng Yao , Lin Yan , Nie Ruifang , Zheng Yang , Liu Yanzhao , Guo Li , Wu Yong
Published: January 2018

A general protocol for the N‐thioetherification of NH‐sulfoximines has been developed. Catalyzed by [Cu(DMAP)4I]I, N‐sulfenyl sulfoximines were synthesized by a one‐pot cascade reaction with commercially available thiophenols as the sulfur source at room temperature. The protocol has mild reaction conditions, is operationally simple, and affords the corresponding products with good yields and excellent tolerance of functional groups.
Optimization of pressurized liquid extraction by response surface methodology of Goji berry (Lycium barbarum L.) phenolic bioactive compounds
Authors: Tripodo Giusy , Ibáñez Elena , Cifuentes Alejandro , Gilbert‐López Bienvenida , Fanali Chiara
Published: January 2018

Pressurized liquid extraction (PLE) has been used for the first time in this work to extract phenolic compounds from Goji berries according to a multilevel factorial design using response surface methodology. The global yield (% w/dw, weight/dry‐weight), total phenolic content (TPC), total flavonoid (TF) and antioxidant activity (determined via ABTS assay, expressed as TEAC value) were used as response variables to study the effects of temperature (50–180°C) and green solvent composition (mixtures of ethanol/water). Phenolic compounds characterization was performed by high performance liquid chromatography–diode array detector–tandem mass spectrometry (HPLC‐DAD‐MS/MS). The optimum PLE conditions predicted by the model were as follows: 180°C and 86% ethanol in water with a good desirability value of 0.815. The predicted conditions were confirmed experimentally and once the experimental design was validated for commercial fruit samples, the PLE extraction of phenolic compounds from three different varieties of fruit samples (Selvatico mongolo, Bigol, and Polonia) was performed. Nine phenolic compounds were tentatively identified in these extracts, including phenolic acids and their derivatives, and flavonols. The optimized PLE conditions were compared to a conventional solid‐liquid extraction, demonstrating that PLE is a useful alternative to extract phenolic compounds from Goji berry.