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131.
Pfeifer P Aston L Banks M Barker S Burress J Carter S Coleman J Crockett S Faulhaber C Flavin J Gordon M Hardcastle L Kallenborn Z Kemiki M Lapilli C Pobst J Schott R Shah P Spellerberg S Suppes G Taylor D Tekeei A Wexler C Wood M Buckley P Breier T Downing J Eastman S Freeze P Graham S Grinter S Howard A Martinez J Radke D Vassalli T Ilavsky J 《Chaos (Woodbury, N.Y.)》2007,17(4):041108
132.
We report on the development of a fiber-based laser transmitter designed for active remote sensing spectroscopy. The transmitter uses a master oscillator power amplifier (MOPA) configuration with a distributed feedback diode-laser master oscillator and an erbium-doped fiber amplifier. The output from the MOPA is frequency-doubled with a periodically poled potassium titanium oxide phosphate crystal. With 35 W of single-frequency peak optical pump power, 8 W of frequency-doubled peak power was achieved. The utility of this single-frequency, wavelength tunable, power scalable laser was then demonstrated in a spectroscopic measurement of diatomic oxygen A band. 相似文献
133.
Synthesis and Catalytic Reactions of Nanoparticles formed by Electrospray Ionization of Coinage Metals 下载免费PDF全文
Anyin Li Qingjie Luo Prof. So‐Jung Park Prof. R. Graham Cooks 《Angewandte Chemie (International ed. in English)》2014,53(12):3147-3150
Noble metals can be ionized by electrochemical corrosion and transported by electrospray ionization. Mass spectrometry (MS) showed solvated metal ions as the main ionic constituent of the sprayed droplets. Collection of the electrospray plume on a surface yielded noble metal nanoparticles (NPs) under ambient conditions. The NPs were characterized by several techniques. Under typical conditions, capped‐nanoparticle sizes averaged 2.2 nm for gold and 6.5 nm for silver. The gold nanoparticles showed high catalytic activity in the reduction of p‐nitrophenol by NaBH4. Efficient catalysis was also observed by simply directing the spray of solvated Au+ onto the surface of an aqueous p‐nitrophenol/NaBH4 mixture. Organometallic ions were generated by spiking ligands into the spray solvent: for example, CuI bipyridine cations dominated the spray during Cu electrocorrosion in acetonitrile containing bipyridine. This organometallic reagent was shown to be effective in the radical polymerization of styrene. 相似文献
134.
Jonathan W. Dube Cameron M. E. Graham Prof. Charles L. B. Macdonald Dr. Zachary D. Brown Prof. Philip P. Power Prof. Paul J. Ragogna 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(22):6739-6744
Two unique systems based on low‐coordinate main group elements that activate P4 are shown to quantitatively release the phosphorus cage upon short exposure to UV light. This reactivity marks the first reversible reactivity of P4, and the germanium system can be cycled 5 times without appreciable loss in activity. Theoretical calculations reveal that the LUMO is antibonding with respect to the main group element–phosphorus bonds and bonding with respect to reforming the P4 tetrahedron, providing a rationale for this unprecedented activity, and suggesting that the process is tunable based on the substituents. 相似文献
135.
Saurav Goel Sara Hawi Gaurav Goel Vijay Kumar Thakur Anupam Agrawal Clare Hoskins Oliver Pearce Tanvir Hussain Hari M. Upadhyaya Graham Cross Asa H. Barber 《Materials Today Chemistry》2020
The world is witnessing tumultuous times as major economic powers including the US, UK, Russia, India, and most of Europe continue to be in a state of lockdown. The worst-hit sectors due to this lockdown are sales, production (manufacturing), transport (aerospace and automotive) and tourism. Lockdowns became necessary as a preventive measure to avoid the spread of the contagious and infectious “Coronavirus Disease 2019” (COVID-19). This newly identified disease is caused by a new strain of the virus being referred to as Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS CoV-2; formerly called 2019-nCoV). We review the current medical and manufacturing response to COVID-19, including advances in instrumentation, sensing, use of lasers, fumigation chambers and development of novel tools such as lab-on-the-chip using combinatorial additive and subtractive manufacturing techniques and use of molecular modelling and molecular docking in drug and vaccine discovery. We also offer perspectives on future considerations on climate change, outsourced versus indigenous manufacturing, automation, and antimicrobial resistance. Overall, this paper attempts to identify key areas where manufacturing can be employed to address societal challenges such as COVID-19. 相似文献
136.
William Graham Hoover Carol Griswold Hoover Edward Ronald Smith 《Entropy (Basel, Switzerland)》2022,24(1)
Time-reversible dynamical simulations of nonequilibrium systems exemplify both Loschmidt’s and Zermélo’s paradoxes. That is, computational time-reversible simulations invariably produce solutions consistent with the irreversible Second Law of Thermodynamics (Loschmidt’s) as well as periodic in the time (Zermélo’s, illustrating Poincaré recurrence). Understanding these paradoxical aspects of time-reversible systems is enhanced here by studying the simplest pair of such model systems. The first is time-reversible, but nevertheless dissipative and periodic, the piecewise-linear compressible Baker Map. The fractal properties of that two-dimensional map are mirrored by an even simpler example, the one-dimensional random walk, confined to the unit interval. As a further puzzle the two models yield ambiguities in determining the fractals’ information dimensions. These puzzles, including the classical paradoxes, are reviewed and explored here. 相似文献
137.
A set of computer programs has been written in FORTRAN and in BASIC to allow automation of data acquisition from a TRONAC titration calorimeter and calculation of the concentration of titrant or titrand in an acid-base reaction; the heat capacity of a solution and enthalpies of reaction may also be calculated. The enthalpy change of a reaction and equilibrium constant can also be determined under certain conditions. 相似文献
138.
Isabel V. L. Wilkinson Kelly J. Perkins Hannah Dugdale Lee Moir Aini Vuorinen Maria Chatzopoulou Sarah E. Squire Sebastian Monecke Alexander Lomow Marcus Geese Philip D. Charles Peter Burch Jonathan M. Tinsley Graham M. Wynne Stephen G. Davies Francis X. Wilson Fraydoon Rastinejad Shabaz Mohammed Kay E. Davies Angela J. Russell 《Angewandte Chemie (International ed. in English)》2020,59(6):2420-2428
Duchenne muscular dystrophy (DMD) is a fatal muscle‐wasting disease arising from mutations in the dystrophin gene. Upregulation of utrophin to compensate for the missing dystrophin offers a potential therapy independent of patient genotype. The first‐in‐class utrophin modulator ezutromid/SMT C1100 was developed from a phenotypic screen through to a Phase 2 clinical trial. Promising efficacy and evidence of target engagement was observed in DMD patients after 24 weeks of treatment, however trial endpoints were not met after 48 weeks. The objective of this study was to understand the mechanism of action of ezutromid which could explain the lack of sustained efficacy and help development of new generations of utrophin modulators. Using chemical proteomics and phenotypic profiling we show that the aryl hydrocarbon receptor (AhR) is a target of ezutromid. Several lines of evidence demonstrate that ezutromid binds AhR with an apparent KD of 50 nm and behaves as an AhR antagonist. Furthermore, other reported AhR antagonists also upregulate utrophin, showing that this pathway, which is currently being explored in other clinical applications including oncology and rheumatoid arthritis, could also be exploited in future DMD therapies. 相似文献
139.
Lydia A. Panther Dr. Daniel P. Guest Dr. Andrew McGown Hugo Emerit Dr. Raysa Khan Tareque Dr. Arathy Jose Mr. Chris M. Dadswell Dr. Simon J. Coles Dr. Graham J. Tizzard Dr. Ramón González-Méndez Dr. Charles A. I. Goodall Prof. Mark C. Bagley Prof. John Spencer Dr. Barnaby W. Greenland 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(49):e202201444
Solvent-free synthesis by using a vibratory ball mill (VBM) offers the chance to access new chemical reactivity, whilst reducing solvent waste and minimising reaction times. Herein, we report the core functionalisation of N,N’-bis(2-ethylhexyl)-2,6-dibromo-1,4,5,8-naphthalenetetracarboxylic acid (Br2-NDI) by using Suzuki, Sonogashira and Buchwald–Hartwig coupling reactions. The products of these reactions are important building blocks in many areas of organic electronics including organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs) and organic photovoltaic cells (OPVCs). The reactions proceed in as little as 1 h, use commercially available palladium sources (frequently Pd(OAc)2) and are tolerant to air and atmospheric moisture. Furthermore, the real-world potential of this green VBM protocol is demonstrated by the double Suzuki coupling of a monobromo(NDI) residue to a bis(thiophene) pinacol ester. The resulting dimeric NDI species has been demonstrated to behave as an electron acceptor in functioning OPVCs. 相似文献
140.
The Direct Synthesis of Hydrogen Peroxide Using Platinum‐Promoted Gold–Palladium Catalysts 下载免费PDF全文
Dr. Jennifer K. Edwards James Pritchard Li Lu Marco Piccinini Greg Shaw Dr. Albert F. Carley David J. Morgan Prof. Christopher J. Kiely Prof. Graham J. Hutchings 《Angewandte Chemie (International ed. in English)》2014,53(9):2381-2384
The direct synthesis of hydrogen peroxide offers a potentially green route to the production of this important commodity chemical. Early studies showed that Pd is a suitable catalyst, but recent work indicated that the addition of Au enhances the activity and selectivity significantly. The addition of a third metal using impregnation as a facile preparation method was thus investigated. The addition of a small amount of Pt to a CeO2‐supported AuPd (weight ratio of 1:1) catalyst significantly enhanced the activity in the direct synthesis of H2O2 and decreased the non‐desired over‐hydrogenation and decomposition reactions. The addition of Pt to the AuPd nanoparticles influenced the surface composition, thus leading to the marked effects that were observed on the catalytic formation of hydrogen peroxide. In addition, an experimental approach that can help to identify the optimal nominal ternary alloy compositions for this reaction is demonstrated. 相似文献