bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Transport with Ultralow Friction through Partially Exfoliated g‐C3N4 Nanosheet Membranes with Self‐Supporting Spacers
Authors: Wang Yanjie , Li Libo , Wei Yanying , Xue Jian , Chen Huang , Ding Li , Caro Jürgen , Wang Haihui 
Published: June 2017

AbstractTwo‐dimensional (2D) graphitic carbon nitride (g‐C3N4) nanosheets show brilliant application potential in numerous fields. Herein, a membrane with artificial nanopores and self‐supporting spacers was fabricated by assembly of 2D g‐C3N4 nanosheets in a stack with elaborate structures. In water purification the g‐C3N4 membrane shows a better separation performance than commercial membranes. The g‐C3N4 membrane has a water permeance of 29 L m−2 h−1 bar−1 and a rejection rate of 87 % for 3 nm molecules with a membrane thickness of 160 nm. The artificial nanopores in the g‐C3N4 nanosheets and the spacers between the partially exfoliated g‐C3N4 nanosheets provide nanochannels for water transport while bigger molecules are retained. The self‐supported nanochannels in the g‐C3N4 membrane are very stable and rigid enough to resist environmental challenges, such as changes to pH and pressure conditions. Permeation experiments and molecular dynamics simulations indicate that a novel nanofluidics phenomenon takes place, whereby water transport through the g‐C3N4 nanosheet membrane occurs with ultralow friction. The findings provide new understanding of fluidics in nanochannels and illuminate a fabrication method by which rigid nanochannels may be obtained for applications in complex or harsh environments.
Orbital Analysis of Carbon‐13 Chemical Shift Tensors Reveals Patterns to Distinguish Fischer and Schrock Carbenes
Authors: Yamamoto Keishi , Gordon Christopher P. , Liao Wei‐Chih , Copéret Christophe , Raynaud Christophe , Eisenstein Odile 
Published: June 2017

AbstractFischer and Schrock carbenes display highly deshielded carbon chemical shifts (>250 ppm), in particular Fischer carbenes (>300 ppm). Orbital analysis of the principal components of the chemical shift tensors determined by solid‐state NMR spectroscopy and calculated by a 2‐component DFT method shows specific patterns that act as fingerprints for each type of complex. The calculations highlight the role of the paramagnetic term in the shielding tensor especially in the two most deshielded components (σ11 and σ22). The paramagnetic term of σ11 is dominated by coupling σ(M=C) with π*(M=C) through the angular momentum operator perpendicular to the σ and π M=C bonds. The highly deshielded carbon of Fischer carbenes results from the particularly low‐lying π*(M=C) associated with the CO ligand. A contribution of the coupling of π(M=C) with σ*(M=C) is found for Schrock and Ru‐based carbenes, indicating similarities between them, despite their different electronic configurations (d0 vs. d6).
Tailor‐made Molecular Cobalt Catalyst System for the Selective Transformation of Carbon Dioxide to Dialkoxymethane Ethers
Authors: Schieweck Benjamin G. , Klankermayer Jürgen 
Published: June 2017

AbstractHerein a non‐precious transition‐metal catalyst system for the selective synthesis of dialkoxymethane ethers from carbon dioxide and molecular hydrogen is presented. The development of a tailored catalyst system based on cobalt salts in combination with selected Triphos ligands and acidic co‐catalysts enabled a synthetic pathway, avoiding the oxidation of methanol to attain the formaldehyde level of the central CH2 unit. This unprecedented productivity based on the molecular cobalt catalyst is the first example of a non‐precious transition‐metal system for this transformation utilizing renewable carbon dioxide sources.
Optically Triggered Melting of DNA on Individual Semiconducting Carbon Nanotubes
Authors: Wang Chunyan , Meany Brendan , Wang YuHuang 
Published: June 2017

AbstractOptical excitation of nanostructures is known to induce local heating, a phenomenon that has been intensely exploited for drug release, gene delivery, cancer thermotherapy, and energy harvesting. However, the effect is typically small requiring collective heating of a large concentration or aggregates of particles. Herein, we show that optical excitation of individual semiconducting single‐walled carbon nanotubes triggers strongly localized heating adequate to melt non‐covalently attached double‐stranded oligonucleotides in solution. In contrast to conventional thermal dehybridization, this optically triggered DNA melting occurs at a solution temperature that is 22 °C lower than the DNA melting temperature. This unexpectedly large localized optical heating effect provides important new insights to design selective optical nanoheaters at the single particle level.
Expanding the Boundaries of Water‐Tolerant Frustrated Lewis Pair Hydrogenation: Enhanced Back Strain in the Lewis Acid Enables the Reductive Amination of Carbonyls
Authors: Dorkó Éva , Szabó Márk , Kótai Bianka , Pápai Imre , Domján Attila , Soós Tibor 
Published: June 2017

AbstractThe development of a boron/nitrogen‐centered frustrated Lewis pair (FLP) with remarkably high water tolerance is presented. As systematic steric tuning of the boron‐based Lewis acid (LA) component revealed, the enhanced back‐strain makes water binding increasingly reversible in the presence of relatively strong base. This advance allows the limits of FLP's hydrogenation to be expanded, as demonstrated by the FLP reductive amination of carbonyls. This metal‐free catalytic variant displays a notably broad chemoselectivity and generality.
Living and Conducting: Coating Individual Bacterial Cells with In Situ Formed Polypyrrole
Authors: Song Rong‐Bin , Wu YiChao , Lin Zong‐Qiong , Xie Jian , Tan Chuan Hao , Loo Joachim Say Chye , Cao Bin , Zhang Jian‐Rong , Zhu Jun‐Jie , Zhang Qichun 
Published: June 2017

AbstractCoating individual bacterial cells with conjugated polymers to endow them with more functionalities is highly desirable. Here, we developed an in situ polymerization method to coat polypyrrole on the surface of individual Shewanella oneidensis MR‐1, Escherichia coli, Ochrobacterium anthropic or Streptococcus thermophilus. All of these as‐coated cells from different bacterial species displayed enhanced conductivities without affecting viability, suggesting the generality of our coating method. Because of their excellent conductivity, we employed polypyrrole‐coated Shewanella oneidensis MR‐1 as an anode in microbial fuel cells (MFCs) and found that not only direct contact‐based extracellular electron transfer is dramatically enhanced, but also the viability of bacterial cells in MFCs is improved. Our results indicate that coating individual bacteria with conjugated polymers could be a promising strategy to enhance their performance or enrich them with more functionalities.
A Molecular Boroauride: A Donor–Acceptor Complex of Anionic Gold
Authors: Taylor Jordan W. , McSkimming Alex , Moret Marc‐Etienne , Harman W. Hill 
Published: June 2017

AbstractGold is unique among the transition metals in that it is stable as an isolated anion (auride). Despite this fact, the coordination chemistry of anionic gold is virtually nonexistent, and this unique oxidation state is not readily exploited in conventional solution chemistry owing to its high reactivity. Through the use of a new molecular scaffold based on diboraanthracene (B2P2, 1), we have overcome these issues by avoiding the intermediacy of zerovalent gold and stabilizing the highly reduced gold anion through acceptor interactions. We have thus synthesized a molecular boroauride [(B2P2)Au]− ([2]−) and showed its reversible conversion between Au−I and AuI states. Through a combination of spectroscopic and computational studies, we show the neutral state to be a AuI complex with a ligand radical anion. Bonding analyses (NBO and QTAIM) and the isolobal relationship between gold and hydrogen provide support for the description of [2]− as a boroauride complex.
Pyxipyrrolones: Structure Elucidation and Biosynthesis of Cytotoxic Myxobacterial Metabolites
Authors: Kjaerulff Louise , Raju Ritesh , Panter Fabian , Scheid Ullrich , Garcia Ronald , Herrmann Jennifer , Müller Rolf 
Published: June 2017

AbstractIn the search for new secondary metabolites from myxobacteria, a strain from the genus Pyxidicoccus was investigated. This led to the identification of a new class of natural products showing structural novelty and interesting biological activity. Isolation and structure elucidation of two analogues led to the identification of pyxipyrrolone A and B, harboring the novel 3‐methylene‐2,3,4,5,6,7,8,9‐octahydro‐1H‐benzo[e]isoindol‐1‐one scaffold. Mosher's ester analysis combined with NMR studies allowed the determination of all stereocenters but one. Genome sequencing of the producer strain led to the identification of a putative biosynthetic gene cluster for the pyxipyrrolones. The compounds showed activity against several cancer cell lines (μm range) with pyxipyrrolone B having 2‐ to 11‐fold higher activity than A, although they differ only by one methylene group.
Pd nanoparticles supported on CeO2 as efficient catalyst for hydrogen generation from formaldehyde solution at room temperature
Authors: Feng Tao , Tang Ranxiao , Shang Ningzhao , Feng Cheng , Gao Shutao , Wang Chun 
Published: June 2017

A facile and efficient method for facilitating hydrogen generation from formaldehyde aqueous solution was developed using Pd nanoparticles supported on CeO2 (Pd/CeO2) as the catalyst. The prepared Pd/CeO2 catalyst exhibited 100% H2 selectivity and excellent catalytic activity for formaldehyde dehydrogenation with the initial rate of 2089 ml min−1 gPd−1 at room temperature and atmospheric pressure without any extra additive. The prepared catalyst was stable and reusable, and its catalytic activity kept almost unchanged after it was reused for the fifth run. Therefore, it is considered that this Pd/CeO2 based hydrogen generation system may serve as an alternative hydrogen supply candidate for practical application.
Efficient and green catalytic system incorporating new benzimidazolium salts for the Sonogashira cross‐coupling reaction
Authors: Yavuz Kemal , Küçükbay Hasan 
Published: June 2017

A number of novel benzimidazole salts were synthesized and their structures were determined using 1H NMR, 13C NMR and infrared spectroscopic techniques and elemental analysis. A catalyst system consisting of Pd(OAc)2 and copper nanoparticles in the presence of Cs2CO3 and incorporating the novel benzimidazole salts in poly(ethylene glycol) solvent significantly improved the yields of Sonogashira reactions between aryl halides and phenylacetylene under microwave irradiation in 10 min.
The effects of graphene oxide on the properties and drug delivery of konjac glucomannan hydrogel
Authors: Yuan Yi , Yan Zhiming , Mu Ruo‐Jun , Wang Lin , Gong Jingni , Hong Xin , Haruna Maryam Hajia , Pang Jie 
Published: June 2017

ABSTRACTKonjac glucomannan (KGM) hydrogel has good potential application in food and medical science, although to achieve this, the physical and mechanical properties need further improvement. In this study, graphene oxide (GO) was used to improve the functionality of KGM hydrogel. KGM/GO hydrogels were prepared by freezing the alkaline KGM/GO sols. Rotational rheometer was used to study the rheological properties of different alkaline KGM/GO sols. Fourier transform infrared, Raman, differential scanning calorimetry, thermogravimetric analyses, and scanning electron microscopy were used to evaluate the structure and properties of the hydrogels. In addition, different pH solutions and an in vitro assay were used to study the swelling property and the release behavior of KGM/GO hydrogels, respectively. The result revealed strong hydrogen‐bond interaction between KGM and GO. The incorporation of GO highly improved the gel properties of KGM/GO sol, higher thermal stability, and more compact structure of KGM/GO hydrogels. KGM/GO hydrogels showed better swelling properties in deionized‐distilled water and pH 7.2 PBS. The release of 5‐aminosalicylic acid (5‐ASA) from KGM/GO (KG4) hydrogel was different in various pH media, but the initial burst release effect was very severe. Therefore, incorporation of GO have a good potential in enhancing the properties of KGM hydrogel, but KGM/GO hydrogel is not an ideal carrier for 5‐ASA release. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45327.
Global PID Control of Robot Manipulators Equipped with PMSMs
Authors: Hernández‐Guzmán V. M. , Orrante‐Sakanassi J. 
Published: June 2017

AbstractThis paper is concerned with PID position regulation of robot manipulators actuated by permanent magnet synchronous motors (PMSMs). We present a global asymptotic stability proof when the electric dynamics of these actuators is taken into account. Our controller is so simple that it differs from standard field oriented control (SFOC) of PMSMs in only three simple nonlinear terms that have to be added and a nonlinear PID controller which is used instead of a classical PID controller. Thus, our proposal represents the closest result to SFOC of PMSMs provided with a formal global asymptotic stability proof. We present an advancement, if modest, towards presenting a global stability proof for SFOC when used in robotics.
Online Algebraic Identification Approach of Continuous Linear Time Delay Systems
Authors: Mhamdi Abdelbacet , Ibn Taarit Kaouther , Ksouri Moufida 
Published: June 2017

AbstractIn this paper, we propose an online algebraic method to identify linear continuous time delay process from step response, in presence of unknown initial state and constant load disturbance. The identification mechanism is split into two sequential steps. The time delay and dynamic of the plant is estimated firstly through a spectral formulation. In the next stage, the transient regime is deduced from a linear regression. To improve the robustness of the proposed method, a local convolution by sigmoid function is proposed. Simulation results are provided, at last, to show the effectiveness of our conceived approach.
Chemical tools to modulate 2‐arachidonoylglycerol biosynthesis
Authors: Deng Hui , van der Stelt Mario 
Published: June 2017

Abstract2‐Arachidonoylglycerol (2‐AG) is an important endogenous signaling lipid that activates the cannabinoid receptors (CB1R and CB2R), thereby regulating a diverse range of physiological processes including anxiety, appetite, inflammation, memory, pain sensation, and nociception. Diacylglycerol lipases (DAGLs) are the principle enzymes responsible for 2‐AG biosynthesis. Recently, the (patho)physiological functions of DAGLs have been explored by both genetic methods and chemical tools. This review will focus on the recent efforts to develop highly selective and in vivo active DAGLs inhibitors using activity‐based protein profiling.
A tricorn‐rhodamine fluorescent chemosensor for detection of Co2+ ions
Authors: Li Jing , Han Shuhua 
Published: June 2017

AbstractA novel chemosensor TrisRh based on tris(2‐aminoethyl)amine and rhodamine 6G is designed and synthesized as a fluorescence turn‐on probe for Co2+ ions that is paramagnetic with a property of quenching fluorescence. Rhodamine spirolactam forms are nonfluorescent, whereas, ring‐opening of corresponding spirocyclic induced by Co2+ results in strong fluorescence emission. Upon the addition of Co2+ ions, TrisRh can display significant enhancements in absorbance and fluorescence intensity as well as evident colorific transformation, which can be perceived by the naked eye. The association stoichiometry of TrisRh to Co2+ ions was inferred to be 1:1 through Job's plot and electrospray ionization mass spectrometry analysis. The binding model was speculated from Fourier transform infrared spectra and 1H–nuclear magnetic resonance technologies. Significantly, the limit of detection was determined to be as low as 1.22 nmol. Furthermore, TrisRh can exhibit robust anti‐jamming ability against other interference metal ions.
A colorimetric and fluorescent chemosensor for selective detection of Cu2+ based on a new diarylethene with a benzophenone hydrazone unit
Authors: Li Lili , Li Hui , Liu Gang , Pu Shouzhi 
Published: June 2017

AbstractA new photochromic diarylethene based on benzophenone hydrazone has been synthesized. Its photochromic and fluorescent properties changed upon alternating irradiation with UV/Vis light and adding Cu2+/EDTA in methanol, which showed that the diarylethene could be served as a colorimetric and fluorescent chemosensor for selective detection of Cu2+ based on internal charge transfer processes. The colorimetric and turn‐off fluorescent selective detection of Cu2+ was attributed to the 2:1 complex of the diarylethene and Cu2+. The binding constant (Ka) was 1.53 × 104 L mol−1 and the limit of detection of the diarylethene for Cu2+ was calculated to be 1.45 × 10−6 mol L−1. In addition, the metal‐responsive photochromic behavior of diarylethene was applied successfully to the construction of a molecular logic circuit.
One‐pot synthesis of fluorescent nitrogen‐doped carbon dots with good biocompatibility for cell labeling
Authors: Zhang Zhengwei , Yan Kun , Yang Qiulian , Liu Yanhua , Yan Zhengyu , Chen Jianqiu 
Published: June 2017

AbstractHere we report an easy and economical hydrothermal carbonization approach to synthesize the fluorescent nitrogen‐doped carbon dots (N‐CDs) that was developed using citric acid and triethanolamine as the precursors. The synthesis conditions were optimized to obtain the N‐CDs with superior fluorescence performances. The as‐prepared N‐CDs are monodispersed sphere nanoparticles with good water solubility, and exhibited strong fluorescence, favourable photostability and excitation wavelength‐dependent behavior. Furthermore, the in vitro cytotoxicity and cellular labeling of N‐CDs were investigated using the rat glomerular mesangial cells. The results showed the N‐CDs have more inconspicuous cytotoxicity and better biosafety in comparison with ZnSe quantum dots, although both targeted the cells successfully. Considering their admirable photostability, low toxicity and good compatibility, the as‐obtained N‐CDs could have potential applications in biosensors, cellular imaging, and other fields.
Self‐assembly of t‐butyloxycarbonyl protected dipeptide methyl esters composed of leucine, isoleucine, and valine into highly organized structures from alcohol and aqueous alcohol mixtures
Authors: Subbalakshmi Chivukula , Basak Pratyay , Nagaraj Ramakrishnan 
Published: June 2017

AbstractShort peptides composed of phenylalanine and sequences derived from amyloidogenic peptides have the ability to self‐assemble to form nanostructures including hydrogels. The self‐assembly of peptides composed of only hydrophobic amino acids and aliphatic protecting groups have not been investigated in detail. We have examined various aspects of nanostructures formed by N‐terminal t‐butyloxycarbonyl‐protected aliphatic dipeptide methyl esters dissolved in various solvents. Scanning electron microscopic images indicate that depending on the sequence, position of the amino acid and solvent of dissolution, the peptides self‐assemble into superstructures such as nanotubes and needles particularly from aqueous mixtures of organic solvents. Crystallization was not required for self‐assembly into nanostructures. Circular dichroism and attenuated total internal reflection fourier transform infrared spectroscopy studies indicate that the peptides adopt β‐conformation in the superstructures both in solution and solid state. The nanostructures composed of entirely aliphatic moieties have the ability to bind to aromatic dyes such as Rhodamine 6G, Nile red and Congo red. They also bind to Thioflavin T although the structures do not resemble amyloid fibrils. The powder X‐ray diffraction patterns suggest distinctive packing of the monomers. These structures are stabilized by intermolecular hydrogen bonds and hydrophobic interactions resulting in superstructures containing long distance order and were devoid of hemolytic activity.
From physical to digital in structural engineering classrooms using digital fabrication
Authors: Chacón Rolando , Codony David , Toledo Álvaro 
Published: June 2017

AbstractIn this paper, a set of digital artifacts related to simple examples of structural engineering are presented. The artifacts are real‐time applications and visualizations of typical problems students from the architecture, engineering, and construction (AEC) schools are acquainted with. The real‐time nature of the examples allow a high level of interaction between humans and the classic visualization of results, namely, bending and shear force diagrams, internal stresses distributions, and contour plots. These artifacts may provide in AEC a twofold educational target: (i) for users, to provide visual understanding in real time of typical problems that must be understood in classic lectures of structural engineering; (ii) for developers, to provide meaningful applications of applied digital fabrication using sensors, microcontrollers, and GUI's and their potential in the development of tools related to Structural Health Monitoring (SHM) and the Internet of Things (IoT) among students of the AEC sector.
Inappropriate shock in a subcutaneous cardiac defibrillator due to residual air
Authors: Lee Shawn , Souvaliotis Nektarios , Mehta Davendra , Suri Ranjit 
Published: June 2017

Key Clinical MessageInappropriate shock due to residual air in subcutaneous implantable cardiac defibrillators is not a well‐known complication. Obtaining overpenetrated X‐rays, recognizing electrocardiogram findings, limiting blunt finger dissection, and switching to sense at another vector are techniques which might lead to avoidance of unnecessary wound exploration or device removal.
Kinetics of CO2 Adsorption/Desorption of Polyethyleneimine‐Mesoporous Silica
Authors: Al-Marri Mohammed J. , Kuti Yussuf O. , Khraisheh Majeda , Kumar Anand , Khader Mahmoud M. 
Published: June 2017

AbstractThe kinetics of adsorption of CO2 on solid sorbents based on polyethyleneimine/mesoporous silica (PEI/MPS) was studied by following the mass gain during CO2 flow. Linear (PEI‐423) and branched (PEI‐10k) polymers were studied. The solid sorbents were synthesized by impregnating the PEI into MPS foam. The kinetics of adsorption was fitted with a double‐exponential model. In contrast, the desorption process obeyed first‐order kinetics. The activation energy of desorption of PEI‐423 was lower than that of PEI‐10k, presumably because the branched polymer required more energy to expose its nitrogen to CO2. To increase the CO2 sorption capacity, the MPS was treated with nonionic surfactant materials prior to impregnation with PEI. This also lowered the maximum sorption temperature and desorption activation energies.
Fluidic Manufacture of Star‐Shaped Gold Nanoparticles
Authors: Silvestri Alessandro , Lay Luigi , Psaro Rinaldo , Polito Laura , Evangelisti Claudio 
Published: June 2017

AbstractStar‐shaped gold nanoparticles (StarAuNPs) are extremely attractive nanomaterials, characterized by localized surface plasmon resonance which could be potentially employed in a large number of applications. However, the lack of a reliable and reproducible synthetic protocols for the production of StarAuNPs is the major limitation to their spreading. For the first time, here we present a robust protocol to manufacture reproducible StarAuNPs by exploiting a fluidic approach. Star‐shaped AuNPs have been synthesized by means of a seed‐less protocol, employing ascorbic acid as reducing agent at room temperature. Moreover, the versatility of the bench‐top microfluidic protocol has been exploited to afford hydrophilic, hydrophobic and solid‐supported engineered StarAuNPs, by avoiding intermediate NP purifications.