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991.
992.
Jessica Barrientos Barria Alexandre Dobroc Hélène Coudert-Alteirac Myriam Raybaut Nicolas Cézard Jean-Baptiste Dherbecourt Thomas Schmid Basile Faure Grégoire Souhaité Jacques Pelon Jean-Michel Melkonian Antoine Godard Michel Lefebvre 《Applied physics. B, Lasers and optics》2014,117(1):509-518
We report on the remote sensing capability of an integrated path differential absorption lidar (IPDIAL) instrument, for multi-species gas detection and monitoring in the 3.3–3.7 µm range. This instrument is based on an optical parametric source composed of a master oscillator-power amplifier scheme—whose core building block is a nested cavity optical parametric oscillator—emitting up to 10 µJ at 3.3 µm. Optical pumping is realized with an innovative single-frequency, 2-kHz repetition rate, nanosecond microchip laser, amplified up to 200 µJ per pulse in a single-crystal fiber amplifier. Simultaneous monitoring of mean atmospheric water vapor and methane concentrations was performed over several days by use of a topographic target, and water vapor concentration measurements show good agreement compared with an in situ hygrometer measurement. Performances of the IPDIAL instrument are assessed in terms of concentration measurement uncertainties and maximum remote achievable range. 相似文献
993.
Lydia P.P. Liew Jessica M. Fleming Arlette Longeon Elisabeth Mouray Isabelle Florent Marie-Lise Bourguet-Kondracki Brent R. Copp 《Tetrahedron》2014
A series of 1-indolyl substituted β-carbolines including the natural products hyrtiosulawesine, pityriacitrin and pityriacitrin B were prepared via Pictet–Spengler condensation—oxidation strategy from the corresponding indolyl-acetaldehydes and substituted tryptamines. Efforts to prepare the C-1 methylene-linked β-carboline analogues for structure–activity relationship studies were unsuccessful. Biological evaluation revealed two analogues (5 and 41) to exhibit weak inhibition of phospholipase A2 (IC50 171 and 131 μM, respectively), two to act as antioxidants (3 and 43), and 12 analogues with activity towards a chloroquine-resistant strain (FcB1) of Plasmodium falciparum (IC50 1.0–23 μM). Testing against a panel of 60 human tumour cell lines revealed a general lack of cytotoxic effect for most of the compounds with the exception of β-carboline 42 exhibiting modest antileukaemic activity towards the HL-60(TB) cell line (LC50 4.2 μM). In addition, two novel structures (30 and 32) resulting from aldol condensation followed by Pictet–Spengler cyclisation displayed cytotoxicity with pronounced subpanel specificities towards colon cancer (COLO 205 and HCC-2998) cell lines. 相似文献
994.
Oxytocin (OT) is an endogenous and therapeutic hormone necessary for maternal health. It is also the subject of fast growing research in the field of behavioral science. This article describes a rapid CE method using UV detection at 214 nm for the determination of the deamidation products of OT. Deamidation is the most common degradation pathway of peptides and proteins and can lead to reduced therapeutic efficiency of biopharmaceuticals. To achieve a separation of the seven structurally similar desamino peptides from OT, 11 mM sulfobutyl ether β‐CD and 10% v/v MeOH were added to a BGE of 50 mM phosphate buffer at pH 6.0. The assay is linear within ≤5–100 μM for all species with a total analysis time of 12 min. The method was then applied to monitor the heat‐stress degradation of OT at 70°C, where all seven desamino species were observed over a 96 h period. 相似文献
995.
996.
The strain-promoted azide–alkyne cycloaddition (SPAAC) is the most widely used bioorthogonal reaction for imaging azide-labeled glycans in living systems. Rapid SPAAC reactions are essential for visualizing biological processes that occur on a short timescale, and efforts to increase SPAAC reaction rates by modulating the cyclooctyne structure have been highly successful. However, optimizing azido sugar structure for improved SPAAC rates has not been explored. In this study, we show that altering azide position on the sugar ring can have a modest but significant impact on SPAAC reaction rate, which has implications for designing and interpreting experiments involving azide-specific bioorthogonal reactions. 相似文献
997.
Cationic Bis‐N‐Heterocyclic Carbene (NHC) Ruthenium Complex: Structure and Application as Latent Catalyst in Olefin Metathesis
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Dr. Mathieu Rouen Dr. Pierre Queval Laura Falivene Jessica Allard Loïc Toupet Dr. Christophe Crévisy Frédéric Caijo Dr. Olivier Baslé Prof. Luigi Cavallo Dr. Marc Mauduit 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13716-13721
An unexpected cationic bis‐N‐heterocyclic carbene (NHC) benzylidene ether based ruthenium complex ( 2 a ) was prepared through the double incorporation of an unsymmetrical unsaturated N‐heterocyclic carbene (U2‐NHC) ligand that bore an N‐substituted cyclododecyl side chain. The isolation and full characterization (including X‐ray diffraction studies) of key synthetic intermediates along with theoretical calculations allowed us to understand the mechanism of the overall cationization process. Finally, the newly developed complex 2 a displayed interesting latent behavior during ring‐closing metathesis, which could be “switched on” under acidic conditions. 相似文献
998.
Dr. Wei Qin Jessica Lohrman Prof. Shenqiang Ren 《Angewandte Chemie (International ed. in English)》2014,53(28):7316-7319
Nanohybrids consisting of Au nanocluster and polythiophene nanowire assemblies exhibit unique thermal‐responsive optical behaviors and charge‐transfer controlled magnetic and optoelectronic properties. The ultrasmall Au nanocluster enhanced photoabsorption and conductivity effectively improves the photocurrent of nanohybrid based photovoltaics, leading to an increase of power conversion efficiency by 14 % under AM 1.5 illumination. In addition, nanohybrids exhibit electric field controlled spin resonance and magnetic field sensing behaviors, which open up the potential of charge‐transfer complex system where the magnetism and optoelectronics interact. 相似文献
999.
Jessica Z. Bereszczak Marlene Havlik Victor U. Weiss Martina Marchetti-Deschmann Esther van Duijn Norman R. Watts Paul T. Wingfield Guenter Allmaier Alasdair C. Steven Albert J. R. Heck 《Analytical and bioanalytical chemistry》2014,406(5):1437-1446
The capsid of hepatitis B virus (HBV) is a major viral antigen and important diagnostic indicator. HBV capsids have prominent protrusions (‘spikes’) on their surface and are unique in having either T?=?3 or T?=?4 icosahedral symmetry. Mouse monoclonal and also human polyclonal antibodies bind either near the spike apices (historically the ‘α-determinant’) or in the ‘floor’ regions between them (the ‘β-determinant’). Native mass spectrometry (MS) and gas-phase electrophoretic mobility molecular analysis (GEMMA) were used to monitor the titration of HBV capsids with the antigen-binding domain (Fab) of mAb 3120, which has long defined the β-determinant. Both methods readily distinguished Fab binding to the two capsid morphologies and could provide accurate masses and dimensions for these large immune complexes, which range up to ~8 MDa. As such, native MS and GEMMA provide valuable alternatives to a more time-consuming cryo-electron microscopy analysis for preliminary characterisation of virus-antibody complexes. Figure
Monitoring the binding of the antigen-binding domain (Fab) of mAb 3120 to hepatitis B capsids by native MS and GEMMA 相似文献
1000.
Oxidation of a dimethylaminophenyl-substituted urea leads to a > 2000-fold increase in binding strength between the urea and a diamide guest in 0.1 M NBu4B(C6F5)4/CH2Cl2. The strength of this interaction is obscured when NBu4ClO4 or NBu4PF6 is used as the electrolyte due to competition between the neutral guest and the electrolyte anion for H-bonding to the urea cation. 相似文献