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991.
Dr. Milan R. Milovanović Dr. Quentin Dherbassy Dr. Joanna Wencel-Delord Prof. Dr. Françoise Colobert Prof. Dr. Snežana D. Zarić Dr. Jean-Pierre Djukic 《Chemphyschem》2020,21(18):2136-2142
To figure out the possible role of 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) as well as to provide reference thermochemical data in solution, the formation of Lewis acid-base complexes between HFIP (Lewis acid) and a series of 8 different Lewis bases (3 sulfoxides, 3 Nsp2 pyridine derivatives, 1 aromatic amine, 1 cyclic aliphatic ether) was examined by isothermal titration calorimetry (ITC) experiments and static density functional theory augmented with Dispersion (DFT−D) calculations. Measured ITC association enthalpy values (ΔHa) lie between −9.3 and −14 kcal mol−1. Computations including a PCM implicit solvation model produced similar exothermicity of association of all studied systems compared to the ITC data with ΔHa values ranging from −8.5 to −12.7 kcal mol−1. An additional set of calculations combining implicit and explicit solvation by chlorobenzene of the reactants, pointed out the relatively low interference of the solvent with the HFIP-base complexation: its main effect is to slightly enhance the Gibbs energy of the HFIP-Lewis base association. It is speculated that the interactions of bulk HFIP with Lewis bases therefore may significantly intervene in catalytic processes not only via the dynamic microstructuring of the medium but also more explicitly by affecting bonds’ polarization at the Lewis bases. 相似文献
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994.
Theranostics: Polymer Capsules as a Theranostic Tool for a Universal In Vitro Screening Assay—The Case of Lysosomal Storage Diseases (Part. Part. Syst. Charact. 11/2015) 下载免费PDF全文
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996.
Mariusz Barczak Ryszard Dobrowolski Joanna Dobrzyńska Emil Zięba Andrzej Dąbrowski 《Adsorption》2013,19(2-4):733-744
Two groups of amine-functionalized organosilicas have been synthesized: amorphous polysiloxane xerogels (APX) and ordered mesoporous organosilicas (OMO) by co-condensation of tetraethoxysilane and appropriate alkoxysilanes: aminopropyltriethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine. The obtained materials were characterized by sorption measurements, X-ray diffractometry, elemental analysis, transmission electron microscopy, and scanning electron microscopy. The OMO samples have well developed porous structure—the values of specific surface area are in the range 740–840 m2/g. While the APX samples are less porous having the corresponding values in the range 280–520 m2/g. The sizes of the ordered mesopores of OMO are in the range 5.9–6.5 nm while for the APX they are 2.9–12.1 nm indicating structural differences between both groups of the samples. All samples were tested as the sorbents of Pt(II) ions. The influence of various parameters such as pH, contact time, equilibrium concentration on Pt(II) adsorption ability onto prepared adsorbents was studied in detail. Additionally, the effect of chloride concentration on Pt(II) adsorption was investigated. The values of static sorption capacities were in the range of 32–102 mgPt(II)/g and 20–139 mgPt(II)/g for OMO and APX series, respectively. 相似文献
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Agnieszka Maria Jastrzębska Joanna Jureczko Joanna Karcz Antoni Kunicki Wanda Ziemkowska Andrzej Olszyna 《Chemical Papers》2017,71(3):579-595
The present paper gives new insight into the problem of controlling the morphology of reduced graphene oxide/alumina (RGO/Al2O3) nanocomposites. The dry and simplified sol–gel methods of RGO/Al2O3 nanocomposite synthesis were compared and the influence of six key synthesis parameters on the morphology of the resulting nanocomposite powders was investigated to optimize the morphology of RGO/Al2O3 nanocomposites in terms of reducing the undesired agglomeration of RGO/Al2O3 nanocomposite flakes to a significant minority and obtaining the uniform coverage of RGO surface with Al2O3 nanoparticles. Our investigations indicate that, despite the high excess of Al2O3 used (95 wt%), the lowest RGO/Al2O3 flake agglomeration and the formation of a uniform layer composed of Al2O3 nanoparticles with the average size of 58 nm occurred only when 5 wt% of graphene oxide was used as a substrate for the deposition of Al2O3 nanoparticles together with triethyl aluminium as an Al2O3 precursor and dry hexane as the reaction environment. The resulting organic precursor was thermally decomposed at 280 °C for 3 h in air atmosphere (R4 reaction pathway). This was confirmed by the high BET-specific surface area (242.4 m2/g) and the high open porosity (0.7 cm3/g) of the obtained RGO(5 wt%)/Al2O3 nanocomposite. This is also the first study with a detailed discussion of the reactions expected to occur during the synthesis of an RGO/Al2O3 nanocomposite. 相似文献
999.
Minimum Exposure Limits and Measured Relationships Between the Vitamin D,Erythema and International Commission on Non‐Ionizing Radiation Protection Solar Ultraviolet 下载免费PDF全文
Nathan Downs Alfio Parisi Harry Butler Joanna Turner Lisa Wainwright 《Photochemistry and photobiology》2015,91(2):438-449
The International Commission on Non‐Ionizing Radiation Protection (ICNIRP) has established guidelines for exposure to ultraviolet radiation in outdoor occupational settings. Spectrally weighted ICNIRP ultraviolet exposures received by the skin or eye in an 8 h period are limited to 30 J m?2. In this study, the time required to reach the ICNIRP exposure limit was measured daily in 10 min intervals upon a horizontal plane at a subtropical Australian latitude over a full year and compared with the effective Vitamin D dose received to one‐quarter of the available skin surface area for all six Fitzpatrick skin types. The comparison of measured solar ultraviolet exposures for the full range of sky conditions in the 2009 measurement period, including a major September continental dust event, show a clear relationship between the weighted ICNIRP and the effective vitamin D dose. Our results show that the horizontal plane ICNIRP ultraviolet exposure may be used under these conditions to provide minimum guidelines for the healthy moderation of vitamin D, scalable to each of the six Fitzpatrick skin types. 相似文献
1000.
Methods of biological fluids sample preparation – biogenic amines,methylxanthines, water‐soluble vitamins 下载免费PDF全文
Joanna Płonka 《Biomedical chromatography : BMC》2015,29(1):1-20
In recent years demands on the amount of information that can be obtained from the analysis of a single sample have increased. For time and economic reasons it is necessary to examine at the same time larger number of compounds, and compounds from different groups. This can best be seen in such areas as clinical analysis. In many diseases, the best results for patients are obtained when treatment fits the individual characteristics of the patient. Dosage monitoring is important at the beginning of therapy and in the full process of treatment. In the treatment of many diseases biogenic amines (dopamine, serotonin) and methylxanthines (theophylline, theobromine, caffeine) play an important role. They are used as drugs separately or in combination with others to support and strengthen the action of other drugs – for example, the combination of caffeine and paracetamol. Vitamin supplementation may be also an integral part of the treatment process. Specification of complete sample preparation parameters for extraction of the above compounds from biological matrices has been reviewed. Particular attention was given to the preparation stage and extraction methods. This review provides universal guidance on establishing a common procedures across laboratories to facilitate the preparation and analysis of all discussed compounds. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献