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https://www.readbyqxmd.com/read/28944814/one-step-detonation-assisted-synthesis-of-fe3o4-fe-bcnt-composite-towards-high-performance-lithium-ion-batteries
#1
Liyong Du, Chunxiao Xu, Jianjun Liu, Yazhu Lan, Pengwan Chen
An Fe3O4-Fe@BCNT composite was successfully synthesized via detonation of a mixture of hexogen (C3H6N6O6) and ferrocene (C10H10Fe), in which bamboo-like carbon nanotubes encapsulating iron nanoparticles attached to Fe3O4 flakes (up to 58.1%) were formed. In the detonation process, hexogen was used to generate high temperature and high pressure, while ferrocene was used as a carbon source and catalyst. The recovered Fe3O4-Fe@BCNT composite was characterized by TEM, SEM, XRD, XPS, and Raman spectroscopy. The results indicate that multi-walled carbon tubes with a bamboo-like structure are formed, in which iron nanoparticles are encapsulated...
September 25, 2017: Nanoscale
https://www.readbyqxmd.com/read/28944797/a-rapid-scan-vacuum-ftir-method-for-determining-diffusion-coefficients-in-viscous-and-glassy-aerosol-particles
#2
Yun Zhang, Chen Cai, Shu-Feng Pang, Jonathan P Reid, Yun-Hong Zhang
We report a new method to investigate water transport kinetics in aerosol particles by using rapid scan FTIR spectroscopy combined with a custom-built pulse relative humidity (RH) control system. From real time in situ measurements of RH and composition using high time resolution infrared spectroscopy (0.12 s for one spectrum), and through achieving a high rate of RH change (as fast as 60% per second), we are able to investigate the competition between the gas and condensed phase diffusive transport limits of water for particles with mean diameter ∼3 μm and varying phase and viscosity...
September 25, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28944791/coherent-evolution-of-singlet-spin-states-in-photo-phip-and-m2s-experiments
#3
A N Pravdivtsev, A V Yurkovskaya, P A Petrov, H-M Vieth
A consistent theoretical description of the spin dynamics underlying photo-PHIP (para-hydrogen induced polarization) experiments is given and validated experimentally: spectra from zero-quantum coherence (ZQC) "in-phase" and "out-of-phase" were obtained and evolution of ZQCs and the population of singlet spin state was tracked and modeled. Data from recent literature [O. Torres et al., J. Am. Chem. Soc., 2014] are reinterpreted. Advantages of using M2S sequences such as APSOC for detecting photo-PHIP are demonstrated...
September 25, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28944766/magnesium-oxide-nanoparticle-loaded-polycaprolactone-composite-electrospun-fiber-scaffolds-for-bone-soft-tissue-engineering-applications-in-vitro-and-in-vivo-evaluation
#4
Ajay Suryavanshi, Kunal Khanna, K R Sindhu, Jayesh Bellare, Rohit Srivastava
The objective of the present investigation was to assess the potential of magnesium oxide nanoparticle (MgO NP)-loaded electrospun polycaprolactone (PCL) polymer composites as a bone-soft tissue engineering scaffold. MgO NPs were synthesized using a hydroxide precipitation sol-gel method and characterized using field emission gun-scanning electron microscopy/energy-dispersive x-ray spectroscopy (FEG-SEM/EDS), field emission gun-transmission electron microscopy (FEG-TEM), and x-ray diffraction (XRD) analysis...
September 25, 2017: Biomedical Materials
https://www.readbyqxmd.com/read/28944676/multiphoton-absorption-order-of-cspbbr3-as-determined-by-wavelength-dependent-nonlinear-optical-spectroscopy
#5
Felix Ochieng Saouma, Constantinos C Stoumpos, Mercouri G Kanatzidis, Yong Soo Kim, Joon I Jang
CsPbBr3 is a direct-gap semiconductor where optical absorption takes place across the fundamental bandgap. But this all-inorganic halide perovskite typically exhibits above-bandgap emission when excited over an energy level, lying above the conduction-band minimum. We probe this bandgap anomaly using wavelength-dependent multiphoton absorption spectroscopy and find that the fundamental gap is strictly two-photon forbidden, rendering it three-photon absorption (3PA) active. Instead, two-photon absorption (2PA) commences when the two-photon energy is resonant with the optical gap, associated with the level causing the anomaly...
September 25, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28944675/high-performance-flexible-perovskite-solar-cells-on-ultra-thin-glass-implications-of-the-tco
#6
Benjia Dou, Elisa M Miller, Jeffrey A Christians, Erin M Sanehira, Talysa Klein, Frank Barnes, Sean E Shaheen, Sean Garner, Shuvaraj Ghosh, Arindam Mallick, Durga Basak, Maikel F A M van Hest
For halide perovskite solar cells (PSC) to fulfil their vast potential for combining low-cost, high efficiency, and high throughput production they must be scaled using a truly transformative method, such as roll-to-roll processing. Bringing this reality closer to fruition, the present work demonstrates flexible perovskite solar cells with 18.1% power conversion efficiency on flexible Willow Glass substrates. We highlight the importance of the transparent conductive oxide (TCO) layers on device performance by studying various TCOs...
September 25, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28944665/kinetic-study-of-living-ring-opening-metathesis-polymerization-with-third-generation-grubbs-catalysts
#7
Dylan J Walsh, Sii Hong Lau, Michael G Hyatt, Damien Guironnet
The rate of living ring-opening metathesis polymerization (ROMP) of N-hexyl-exo-norbornene-5,6-dicarboximide initiated by Grubbs third-generation catalyst precursors [(H2IMes)(py)2(Cl)2Ru═CHPh] and [(H2IMes)(3-Br-py)2(Cl)2Ru═CHPh] is measured to be independent of catalyst concentration. This result led to the development of a rate law describing living ROMP initiated by a Grubbs third-generation catalyst that includes an inverse first-order dependency in pyridine. Additionally, it is demonstrated that one of the two pyridines coordinated to the solid catalyst is fully dissociated in solution...
September 25, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28944655/metal-nanowire-based-hybrid-electrodes-exhibiting-high-charge-discharge-rates-and-long-lived-electrocatalysis
#8
Rakesh K Pandey, Yuto Kawabata, Satoshi Teraji, Tomohisa Norisuye, Qui Tran-Cong-Miyata, Siowling Soh, Hideyuki Nakanishi
Nanostructured electrodes are at the forefront of advanced materials research, and have been studied extensively in the context of their potential applications in energy storage and conversion. Here, we report on the properties of core-shell (gold-polypyrrole) hybrid nanowires and their suitability as electrodes in electrochemical capacitors and as electrocatalysts. In general, the specific capacitance of electrochemical capacitors can be increased by faradaic reactions, but their charge transfer resistance impedes charge transport, decreasing the capacitance with increasing charge/discharge rate...
September 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28944612/using-individual-functional-channels-of-interest-to-study-cortical-development-with-fnirs
#9
Lindsey J Powell, Ben Deen, Rebecca Saxe
Functional near-infrared spectroscopy (fNIRS) is a noninvasive neuroimaging technique that could be uniquely effective for investigating cortical function in human infants. However, prior efforts have been hampered by the difficulty of aligning arrays of fNIRS optodes placed on the scalp to anatomical or functional regions of underlying cortex. This challenge can be addressed by identifying channels of interest in individual participants, and then testing the reliability of those channels' response profiles in independent data...
September 24, 2017: Developmental Science
https://www.readbyqxmd.com/read/28944564/harzianone-biosynthesis-by-the-biocontrol-fungus-trichoderma
#10
Lena Barra, Jeroen Sidney Dickschat
Analysis of the volatile terpenes produced by seven fungal strains of the genus Trichoderma by use of a closed-loop stripping apparatus (CLSA) revealed a common production of harzianone, a bioactive, structurally unique diterpenoid consisting of a fused tetracyclic 4,5,6,7-membered ring system. The terpene cyclization mechanism was studied by feeding experiments using selectively 13C- and 2H-labeled synthetic mevalonolactone isotopologues, followed by analysis of the incorporation patterns by 13C-NMR spectroscopy and GC/MS...
September 25, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28944396/light-induced-piston-nanoengines-ultrafast-shuttling-of-a-styryl-dye-inside-cucurbit-7-uril
#11
Ekaterina Y Chernikova, Daria V Berdnikova, Yuri V Fedorov, Olga A Fedorova, François Maurel, Gediminas Jonusauskas
The combination of photoactive styryl(pyridinium) dyes and cucurbit[7]uril (CB[7]) in an integrated supramolecular system allowed us to design a novel high speed molecular machine based on the fully reversible shuttling motion of the dye inside the CB[7] host cavity. The driving force of this movement is the electrostatic potential change after the occurrence of intramolecular charge transfer in the excited state of the dye molecule that can be externally controlled by light. Steady-state and time-resolved optical spectroscopy as well as DFT calculations provided an unambiguous evidence for the ultrafast piston-like movement of the system between two states...
September 25, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28944395/combined-measurement-of-directional-raman-scattering-and-surface-plasmon-polariton-cone-from-adsorbates-on-smooth-planar-gold-surfaces
#12
Charles K A Nyamekye, Stephen C Weibel, Jonathan M Bobbitt, Emily A Smith
Directional-surface-plasmon-coupled Raman scattering (directional RS) has the combined benefits of surface plasmon resonance and Raman spectroscopy, and provides the ability to measure adsorption and monolayer-sensitive chemical information. Directional RS is performed by optically coupling a 50 nm gold film to a Weierstrass prism in the Kretschmann configuration and scanning the angle of the incident laser under total internal reflection. The collected parameters on the prism side of the interface include a full surface-plasmon-polariton cone and the full Raman signal radiating from the cone as a function of incident angle...
September 25, 2017: Analyst
https://www.readbyqxmd.com/read/28944388/synthesis-structure-and-excited-state-kinetics-of-heteroleptic-cu-i-complexes-with-a-new-sterically-demanding-phenanthroline-ligand
#13
Lars Kohler, Ryan G Hadt, Dugan Hayes, Lin X Chen, Karen L Mulfort
In this report we describe the synthesis of a new phenanthroline ligand, 2,9-di(2,4,6-tri-isopropyl-phenyl)-1,10-phenanthroline (bL2) and its use as the blocking ligand in the preparation of two new heteroleptic Cu(i)diimine complexes. Analysis of the CuHETPHEN single crystal structures shows a distinct distortion from an ideal tetrahedral geometry around the Cu(i) center, forced by the secondary phenanthroline ligand rotating to accommodate the isopropyl groups of bL2. The increased steric bulk of bL2 as compared to the more commonly used 2,9-dimesityl-1,10-phenanthroline blocking ligand prohibits intramolecular ligand-ligand interaction, which is unique among CuHETPHEN complexes...
September 25, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28944375/influence-of-different-calcium-phosphates-on-an-experimental-adhesive-resin
#14
Isadora Martini Garcia, Vicente Castelo Branco Leitune, Susana Maria Werner Samuel, Fabrício Mezzomo Collares
PURPOSE: To formulate adhesive resins with 2 wt% of hydroxyapatite (HAp), α-tricalcium phosphate (α-TCP), or octacalcium phosphate (OCP) and to compare these groups with an unfilled adhesive regarding the degree of conversion, polymerization rate, microshear bond strength and mineral deposition. MATERIALS AND METHODS: The experimental adhesive resin was formulated mixing 66.6 wt% bisphenol A glycol dimethacrylate (bis-GMA), 33.3 wt% 2-hydroxyethyl methacrylate (HEMA), and a photoinitiator system...
September 21, 2017: Journal of Adhesive Dentistry
https://www.readbyqxmd.com/read/28944309/particle-coatings-but-not-silver-ions-mediate-genotoxicity-of-ingested-silver-nanoparticles-in-a-mouse-model
#15
Sameera Nallanthighal, Cadia Chan, Dhruba J Bharali, Shaker A Mousa, Elizabeth Vásquez, Ramune Reliene
Incorporation of silver nanoparticles (AgNPs) in toothpaste, food containers, dietary supplements and other consumer products can result in oral exposure to AgNPs and/or silver ions (Ag(+)) released from the surface of AgNPs. To examine whether ingestion of AgNPs or Ag(+) results in genotoxic damage and whether AgNP coatings modulate the effect, we exposed mice orally to 20 nm citrate-coated AgNPs, polyvinylpyrrolidone (PVP)-coated AgNPs, silver acetate or respective vehicles at a 4 mg/kg dose (equivalent to 800x the EPA reference dose for Ag) for 7 days...
January 2017: NanoImpact
https://www.readbyqxmd.com/read/28944287/detection-of-pentosidine-cross-links-in-cell-secreted-decellularized-matrices-using-time-resolved-fluorescence-spectroscopy
#16
Debika Mitra, Hussain Fatakdawala, Michael Nguyen-Truong, Amy Creecy, Jeffry Nyman, Laura Marcu, J Kent Leach
Hyperglycemia-mediated, nonenzymatic collagen cross-links such as pentosidine (PENT) can have deleterious effects on cellular interactions with the extracellular matrix (ECM). Present techniques to quantify PENT are limited, motivating the need for improved methods to study the accumulation and contribution of PENT toward diabetic clinical challenges such as impaired bone healing. Current methods for studying PENT are destructive, laborious, and frequently employ oversimplified collagen films that lack the complexity of the native ECM...
September 11, 2017: ACS Biomaterials Science & Engineering
https://www.readbyqxmd.com/read/28944259/observing-plasmon-damping-due-to-adhesion-layers-in-gold-nanostructures-using-electron-energy-loss-spectroscopy
#17
Steven J Madsen, Majid Esfandyarpour, Mark L Brongersma, Robert Sinclair
Gold plasmonic nanostructures with several different adhesion layers have been studied with monochromated electron energy loss spectroscopy in the scanning transmission electron microscope (STEM-EELS) and with surface enhanced Raman spectroscopy (SERS). Compared to samples with no adhesion layer, those with 2nm of Cr or Ti show broadened, lower intensity plasmon peaks as measured with EELS. This broadening is observed in both optically active ("bright") and inactive ("dark") plasmon modes. When the former are probed with SERS, the signal enhancement factor is lower for samples with Cr or Ti, another indication of reduced plasmon resonance...
February 15, 2017: ACS Photonics
https://www.readbyqxmd.com/read/28944255/soft-x-ray-absorption-spectroscopy-of-metalloproteins-and-high-valent-metal-complexes-at-room-temperature-using-free-electron-lasers
#18
Markus Kubin, Jan Kern, Sheraz Gul, Thomas Kroll, Ruchira Chatterjee, Heike Löchel, Franklin D Fuller, Raymond G Sierra, Wilson Quevedo, Christian Weniger, Jens Rehanek, Anatoly Firsov, Hartawan Laksmono, Clemens Weninger, Roberto Alonso-Mori, Dennis L Nordlund, Benedikt Lassalle-Kaiser, James M Glownia, Jacek Krzywinski, Stefan Moeller, Joshua J Turner, Michael P Minitti, Georgi L Dakovski, Sergey Koroidov, Anurag Kawde, Jacob S Kanady, Emily Y Tsui, Sandy Suseno, Zhiji Han, Ethan Hill, Taketo Taguchi, Andrew S Borovik, Theodor Agapie, Johannes Messinger, Alexei Erko, Alexander Föhlisch, Uwe Bergmann, Rolf Mitzner, Vittal K Yachandra, Junko Yano, Philippe Wernet
X-ray absorption spectroscopy at the L-edge of 3d transition metals provides unique information on the local metal charge and spin states by directly probing 3d-derived molecular orbitals through 2p-3d transitions. However, this soft x-ray technique has been rarely used at synchrotron facilities for mechanistic studies of metalloenzymes due to the difficulties of x-ray-induced sample damage and strong background signals from light elements that can dominate the low metal signal. Here, we combine femtosecond soft x-ray pulses from a free-electron laser with a novel x-ray fluorescence-yield spectrometer to overcome these difficulties...
September 2017: Structural Dynamics (Melville, N.Y.)
https://www.readbyqxmd.com/read/28944134/co2-flux-from-javanese-mud-volcanism
#19
M Queißer, M R Burton, F Arzilli, A Chiarugi, G I Marliyani, F Anggara, A Harijoko
Studying the quantity and origin of CO2 emitted by back-arc mud volcanoes is critical to correctly model fluid-dynamical, thermodynamical, and geochemical processes that drive their activity and to constrain their role in the global geochemical carbon cycle. We measured CO2 fluxes of the Bledug Kuwu mud volcano on the Kendeng Fold and thrust belt in the back arc of Central Java, Indonesia, using scanning remote sensing absorption spectroscopy. The data show that the expelled gas is rich in CO2 with a volume fraction of at least 16 vol %...
June 2017: Journal of Geophysical Research. Solid Earth
https://www.readbyqxmd.com/read/28944090/rapid-identification-of-buprenorphine-in-patient-saliva
#20
Stuart Farquharson, Kathryn Dana, Chetan Shende, Zachary Gladding, Jenelle Newcomb, Jessica Dascher, Ismene L Petrakis, Albert J Arias
Buprenorphine is becoming the medication of choice to help patients withdraw from opioid addiction. However, treatment is compromised by the inability of physicians to assess patient usage during scheduled examinations. Here we describe the development of a point-of-care (POC) analyzer that can rapidly measure both illicit and treatment drugs in patient saliva, ideally in the physician's office, and with a degree of accuracy similar to chromatography. The analyzer employs a relatively simple supported liquid extraction to isolate the drugs from the saliva and surface-enhanced Raman spectroscopy (SERS) to detect the drugs...
June 2017: Journal of Analytical & Bioanalytical Techniques
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