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101.
Dagmara Ziembicka Andrzej Olczak Katarzyna Gobis Izabela Korona-Głowniak Anna Pietrzak Ewa Augustynowicz-Kopeć Agnieszka Głogowska Marcin Zaborowski Małgorzata Szczesio 《Acta Crystallographica. Section C, Structural Chemistry》2023,79(7):283-291
Three new 2,6-disubstituted thiosemicarbazone derivatives of pyridine, namely, 2-{amino[6-(pyrrolidin-1-yl)pyridin-2-yl]methylidene}-N,N-dimethylhydrazine-1-carbothioamide, C13H20N6S, 2-{amino[6-(piperidin-1-yl)pyridin-2-yl]methylidene}-N,N-dimethylhydrazine-1-carbothioamide, C14H22N6S, and 2-[amino(6-phenoxypyridin-2-yl)methylidene]-N,N-dimethylhydrazine-1-carbothioamide monohydrate, C15H17N5OS·H2O, have been synthesized and characterized by NMR spectroscopy and low-temperature single-crystal X-ray diffraction. In addition, their antibacterial and anti-yeast activities have been determined. The ability of the tested compounds to inhibit bacterial growth was comparable to vancomycin as a reference drug. Compared to isoniazid (MIC 0.125 and 8 µg ml−1), the compounds showed the ability to inhibit the growth of Mycobacterium tuberculosis to a moderate degree for the standard strain and at the same level or higher (MIC 4–8 µg ml−1) for the resistant strain. All three compounds adopt the zwitterionic form in the crystal structure regardless of the presence or absence of solvent molecules. 相似文献
102.
103.
Bury I Donnio B Gallani JL Guillon D 《Langmuir : the ACS journal of surfaces and colloids》2007,23(2):619-625
Amphiphiles with a dendritic structure are attractive materials as they combine the features of dendrimers with the self-assembling properties and interfacial behavior of amphiphiles. We have designed and synthesized three series of segmented amphiphilic block co-dendrimers (Janus-type) and studied their interfacial properties on the Langmuir trough. Various behaviors are observed with, as a rule, the lowest generation dendrimers behaving more or less like traditional amphiphiles while the larger molecules tend to exhibit more complicated isotherms, with a non-straightforward temperature dependence, one particular molecule seemingly forming supramolecular assemblies spontaneously. The results presented here, obtained on a series of molecules where many parameters have been varied systematically, show the limits that should be kept in mind when designing amphiphilic dendrimers. 相似文献
104.
Lipid nanoparticles based on multiple emulsion (W/O/W) systems are suitable for incorporating hydrophilic active substances, including iridoid glycosides. This study involved optimization of composition of lipid nanoparticles, incorporation of active compounds (aucubin and catalpol), evaluation of stability of the resulting nanocarriers, and characterization of their lipid matrix. Based on 32 factorial design, an optimized dispersion of lipid nanoparticles (solid lipid:surfactant—4.5:1.0 wt.%) was developed, predisposed for the incorporation of iridoid glycosides by emulsification-sonication method. The encapsulation efficiency of the active substances was determined at nearly 90% (aucubin) and 77% (catalpol). Regarding the stability study, room temperature was found to be the most suitable for maintaining the expected physicochemical parameter values (particle size < 100 nm; polydispersity index < 0.3; zeta potential > |± 30 mV|). Characterization of the lipid matrix confirmed the nanometer size range of the resulting carriers (below 100 nm), as well as the presence of the lipid in the stable β’ form. 相似文献
105.
Szydłowska I Nosenko Y Brutschy B Tarakeshwar P Herbich J 《Physical chemistry chemical physics : PCCP》2007,9(36):4981-4991
We present the results of spectroscopic and photophysical investigations of 4-diethylaminopyridine (DEAP) and its 1 : 1 complexes with a number of protic solvents such as water and various alcohols of different acidity isolated under supersonic jet conditions. While a double resonance vibrational spectroscopic method was employed to investigate the size and geometrical structure of jet-cooled clusters, laser-induced fluorescence spectroscopy was used to examine the changes of photophysics induced by complexation of DEAP with solvent molecule(s). The results obtained from ab initio calculations enable the assignment of geometries and of the vibrational spectra of the clusters in the OH-stretch region. The comparison of the experimental and calculated vibrational spectra indicates that the solvent molecule is hydrogen-bonded to the pyridine nitrogen atom. Dual luminescence is observed only for the complexes with alcohols of relatively strong acidity. 相似文献
106.
Izabela Janowska Kambiz Chizari Jean-Hubert Olivier Raymond Ziessel Marc Jacques Ledoux Cuong Pham-Huu 《Comptes Rendus Chimie》2011,14(7-8):663-670
Palladium supported on vertically aligned multi-walled carbon nanotubes (Pd/VA-CNTs) is used as catalyst for the C-C coupling reactions of p-iodonitrobenzene with styrene and ethyl acrylate under microwaves irradiation. Pd/VA-CNTs catalyst exhibits higher activity compared to Pd supported on activated charcoal, under the same reaction conditions. Due to the microwaves irradiation, the kinetics of the reaction is strongly accelerated compared to that obtained with a traditional heating mode. The macroscopic form of aligned CNTs support allows an easy recovery of the catalyst, avoiding a costly post-reaction filtration. In addition, the interaction between the active phase and the support leads to the negligible leaching of palladium during recycling tests. The observed results indicate that Pd/CNTs is a recyclable and stable heterogeneous catalytic system. 相似文献
107.
Vitaliy Datsyuk Milana Lisunova Maria Kasimir Svitlana Trotsenko Kati Gharagozloo-Hubmann Izabela Firkowska Stephanie Reich 《Applied Physics A: Materials Science & Processing》2011,105(4):781-788
We studied the thermal transport properties of multi-walled carbon nanotubes (MWNTs) in polymer and oil matrices. The thermal
conductivity of the oils and polymers increased linearly when adding tubes. We observe a particularly high increase in the
thermal diffusivity of carbon-nanotube-loaded liquid crystal polymers (6×10−5 cm2/s wt%), which is due to a spontaneous alignment of the MWNTs. Carbon nanotubes increased the thermal conductivity of oil
by a factor of three for 20 wt% loading. We found little or no dependence of the thermal enhancement on the specific flavor
of multiwall nanotubes used in the composites. Carbon nanotubes are excellent nanoscale fillers for composites in thermal
management application. 相似文献
108.
Izabela?Majchrzak-Kuc?baEmail author 《Journal of Thermal Analysis and Calorimetry》2012,107(3):911-921
The thermogravimetry (TG) was used for characterization of the fly ash (FA)-based MCM-41 mesoporous materials. MCM-41 mesoporous
materials were synthesized using silica extracts from different FA. The synthesis of MCM-41 from FA was carried out by the
hydrothermal method using the supernatants of coal FA (in the form of sodium silicate) and cationic cetyltrimethylammonium
bromide (CTAB) surfactants as the structure-directing agents. On the basis of the data obtained from the TG analysis, thermal
behaviour of FA-based MCM-41 mesoporous materials was assessed. This study has established the range of temperatures corresponding
to the desorption of water, decomposition of the surfactant and condensation of silanol, thereby making the overall quality
assessment of FA-based MCM-41 mesoporous materials. 相似文献
109.
Agnieszka Adamczyk-Woźniak Michał K. Cyrański Beata T. Frączak Agnieszka Lewandowska Izabela D. Madura Andrzej Sporzyński 《Tetrahedron》2012,68(19):3761-3767
ortho-Iminomethylphenylboronic acids were synthesized from the reaction of 2-formyl–phenylboronic acid with primary aromatic amines. Reduction of these compounds yielded the corresponding aminomethylphenylboronic acids. For both types of the compounds, the crystal structure was determined by single crystal X-ray diffraction method. Hydrogen-bonded dimers with an additional intramolecular B–O–H…N hydrogen bond have been observed. Calculations at MP2/6–31+G** level proved that the most stable form is that with the above-mentioned intramolecular hydrogen bond while the form with dative N→B bond is less favoured. Since the calculated energy difference is small, the competition between possible forms was analyzed in terms of substituent effect stabilization energy (SESE). In the case of p-iminomethylphenylboronic acid, both hydroxyl groups are engaged in intermolecular O–H…O interactions resulting in a supramolecular ribbon motif. 相似文献
110.
Agnieszka Maruszewska Wojciech wiereo Marta Skrka-Majewicz Irena Baranowska-Bosiacka Agata Wszoek Katarzyna Janda Daria Kulis Patrycja Kapczuk Dariusz Chlubek Izabela Gutowska 《Molecules (Basel, Switzerland)》2021,26(14)
Breast milk has the most suitable composition for the proper development in the first year of a child’s life. However, it is often replaced with artificial milk. The aim of the study was to analyze the composition of essential elements: Na, K, Ca, P, Mg, Fe, Zn, Cu, and Mn as well as toxic elements: Ni, Pb, Sr, Li, and In in 18 formulas available in Poland. The daily supply was also estimated. The study was performed by Inductively Coupled Plasma Optical Emission Spectrometry method. The results showed the presence of all essential elements tested, but the content of P and Mn significantly differed from the concentrations declared. Such discrepancies can have significant impact on the daily dose of the bioelements taken. However, the content of elements was within the reference standards established by the EU Directive with exception of P, the amount of which exceeded the norms 5.23–18.80-times. Daily supply of P in tested milk as well as Fe and Mn provided with first and hypoallergenic formula exceeded the adequate intake. Analysis revealed the contamination with harmful elements—Pb, Sr, Li, and In were detected in almost all products. The study confirms the data concerning some discrepancies in composition and the contamination of food and may provide information on the feeding quality of children and estimation of health risk associated with exposure to toxic elements. 相似文献