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11.
Akshay Kumar Hippolyte Durand Elisa Zeno Cyril Balsollier Bastien Watbled Cecile Sillard Sbastien Fort Isabelle Baussanne Naceur Belgacem Daniel Lee Sabine Hediger Martine Demeunynck Julien Bras Gaël De Paëpe 《Chemical science》2020,11(15):3868
Cellulose nanofibrils (CNF) are renewable bio-based materials with high specific area, which makes them ideal candidates for multiple emerging applications including for instance on-demand drug release. However, in-depth chemical and structural characterization of the CNF surface chemistry is still an open challenge, especially for low weight percentage of functionalization. This currently prevents the development of efficient, cost-effective and reproducible green synthetic routes and thus the widespread development of targeted and responsive drug-delivery CNF carriers. We show in this work how we use dynamic nuclear polarization (DNP) to overcome the sensitivity limitation of conventional solid-state NMR and gain insight into the surface chemistry of drug-functionalized TEMPO-oxidized cellulose nanofibrils. The DNP enhanced-NMR data can report unambiguously on the presence of trace amounts of TEMPO moieties and depolymerized cellulosic units in the starting material, as well as coupling agents on the CNFs surface (used in the heterogeneous reaction). This enables a precise estimation of the drug loading while differentiating adsorption from covalent bonding (∼1 wt% in our case) as opposed to other analytical techniques such as elemental analysis and conductometric titration that can neither detect the presence of coupling agents, nor differentiate unambiguously between adsorption and grafting. The approach, which does not rely on the use of 13C/15N enriched compounds, will be key to further develop efficient surface chemistry routes and has direct implication for the development of drug delivery applications both in terms of safety and dosage.DNP-enhanced solid-state NMR unravels the surface chemistry of functionalized nanocellulose. 相似文献
12.
Personne und Schönbein 《Fresenius' Journal of Analytical Chemistry》1862,1(1):369-370
Ohne Zusammenfassung 相似文献
13.
We examine the possibility of producing and evidencing exotic strange matter (strangelets and metastable multi-hypernuclear
objects, MEMO’s), including also pure hyperonic bound states ((ΛΛ)b, (ξΛ)b), at RHIC and LHC. Simulations are presented to estimate the sensitivity of the STAR and ALICE experiments to the detection
of these objects, focusing mainly on metastable short-lived (weak decaying) strange dibaryons, with a particular emphasis
on theH-dibaryon, a six quark-bag bound state (uuddss). 相似文献
14.
Emmanuel Sopbué Fondjo Joseph Tsemeugne Beibam Luc Sondengam Thomas Oppenlaender Hippolyte Kamdem Wabo Pierre Tane Joseph D. Connolly Wim Dehaen Taoufik Rohand Haruhisa Kikuchi Yoshiteru Oshima 《Journal of heterocyclic chemistry》2011,48(6):1295-1301
The coupling reactions of two diazotized 3‐aminothieno[3,4‐c]coumarins were investigated. Compounds 1a , 1b both react with sodium nitrite in concentrated sulphuric acid at 0–5°C to give the diazotized intermediates 2 and 3 , the latter resulting from the acid ‐catalyzed hydrolysis of the lactonic ring of 2 . The in situ formed diazonium salts react with aromatic amines ( 4 ) to afford a series of arylazothiophenes dyes in the form of their ammonium sulfate salts. With diazotized aniline, besides the normally expected phenylazothiophene 10 from the reaction with compound 1a , the corresponding product of acid hydrolysis 11 was also isolated. In at least one of the cases, the thienyl diazonium salt 2 undergoes a Gomberg–Bachmann arylation reaction with p‐nitroaniline to give the 2‐arylthiophene 9 . The direct hydrolysis of compounds 1a , 1b by concentrated sulphuric acid and subsequent oxidative dimerization of the primary product of acid hydrolysis led to compound 12 . J. Heterocyclic Chem., (2011). 相似文献
15.
Dr. Xavier Frogneux Dr. Laura Hippolyte Dr. Dimitri Mercier Dr. David Portehault Prof. Corinne Chanéac Prof. Clément Sanchez Prof. Philippe Marcus Dr. François Ribot Prof. Louis Fensterbank Dr. Sophie Carenco 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(49):11481-11485
N-Heterocyclic carbene (NHC)-stabilized copper nanoparticles (NPs) were synthesized from an NHC–borane adduct and mesitylcopper(I) under thermal conditions (refluxing toluene for 2.5 h). NPs with a size distribution of 11.6±1.8 nm were obtained. The interaction between Cu NPs and NHC ligands was probed by X-ray photoelectron spectroscopy, which showed covalent binding of the NHC to the surface of the NPs. Mechanistic studies suggested that NHC–borane plays two roles: contributing to the reduction of [CuMes]2 to release Cu0 species and providing NHC ligands to stabilize the copper NPs. 相似文献
16.
B. Hippolyte 《The European Physical Journal C - Particles and Fields》2009,62(1):237-242
Measurements at low transverse momentum will be performed at the LHC for studying particle production mechanisms in pp and heavy-ion collisions. Some of the experimental capabilities for bulk matter physics are presented, focusing on tracking
elements and particle identification. In order to anticipate the study of baryon production for both colliding systems at
multi-TeV energies, measurements for identified species and recent model extrapolations are discussed. Several mechanisms
are expected to compete for hadro-production in the low momentum region. For this reason, experimental observables that could
be used for investigating multi-parton interactions and help understanding the “underlying event” content in the first pp collisions at the LHC are also mentioned. 相似文献
17.
Damien P. Debecker Valentin Smeets Margot Van der Verren Hippolyte Meersseman Arango Marty Kinnaer François Devred 《Current Opinion in Green and Sustainable Chemistry》2021
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18.
Stable distributions have heavy tails that are asymptotically Paretian. Accurate computations of stable densities and distribution functions are used to analyze when the Paretian tail actually appears. Implications for estimation procedures are discussed. In addition to numerically locating the mode of a general stable distribution, analytic and numeric results are given for the mode. Extensive tables of stable percentiles have been computed; aspects of these tables and the appropriateness of infinite variance stable models are discussed. 相似文献
19.
B. Hippolyte 《The European Physical Journal C - Particles and Fields》2007,49(1):121-124
Strange quark and hadron production will be studied at the large hadron collider (LHC) energies in order to explore the properties
of both pp and heavy-ion collisions. The ALICE experiment will be specifically efficient in the strange sector with the identification
of baryons and mesons over a wide range of transverse momentum. Dedicated measurements are proposed for investigating chemical
equilibration and bulk properties. Strange particles can also help to probe kinematical regions where hard processes and pQCD
dominate. We try to anticipate here several ALICE analyses to be performed as the first Pb–Pb and pp data will be available.
PACS 25.75.-q; 25.75.Dw 相似文献
20.
Wabo HK Tane P Connolly JD Okunji CC Schuster BM Iwu MM 《Natural product research》2005,19(6):591-595
A novel pyranoquinoline alkaloid 3,4-dihydro-3-hydroxy-5-methoxy-2,2,10-trimethylpyrano [2,3-b]quinoline named tabouensinium chloride (1), was isolated from the stem bark of Araliopsis tabouensis along with twelve known quinoline alkaloids. In addition, the known flindisol, lupeol and beta-sitosterol glucoside were also identified. Their structures were deduced from spectral data. 相似文献