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121.
Catherine M. Clavel Patrycja Nowak-Sliwinska Emilia P?unescu Arjan W. Griffioen Paul J. Dyson 《Chemical science》2015,6(5):2795-2801
Hyperthermia used as an adjuvant with chemotherapy is highly promising in the treatment of certain cancers. Currently, the small molecule drugs used in combination with hyperthermia were not designed for this application. Herein, we report the evaluation of a chlorambucil and a ruthenium compound modified with a long fluorous chain, which exhibit thermoresponsive activity in colorectal adenocarcinoma xenografts in athymic mice in combination with mild hyperthermia (42 °C). Intraperitoneal injection of the derivatives followed by local hyperthermia showed a synergistic tumor growth reduction by 79% and 90% for the chlorambucil and ruthenium-based derivatives, respectively, with the latter exhibiting a higher synergy in combination with hyperthermia compared to the monotherapies. Histological analysis shows that both derivatives in combination with hyperthermia significantly decrease the number of proliferating tumor cells. 相似文献
122.
New procedure for the control of the treatment of industrial effluents to remove volatile organosulfur compounds
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Grzegorz Boczkaj Patrycja Makoś André Fernandes Andrzej Przyjazny 《Journal of separation science》2016,39(20):3946-3956
We present a new procedure for the determination of volatile organosulfur compounds in samples of industrial effluents using dispersive liquid–liquid microextraction and gas chromatography with flame photometric detection. Initially, the extraction parameters were optimized. These included: type and volume of extraction solvent, volume of disperser solvent, salting out effect, pH, time and speed of centrifugation as well as extraction time. The procedure was validated for 30 compounds. The developed procedure has low detection limits of 0.0071–0.49 μg/L and a good precision (relative standard deviation values of 1.2–5.0 and 0.6–4.1% at concentrations of 1 and 10 μg/L, respectively). The procedure was used to determine the content of volatile organosulfur compounds in samples of effluents from the production of bitumens before and after chemical treatment, in which six compounds were identified, including 2‐mercaptoethanol, thiophenol, thioanisole, dipropyl disulfide, 1‐decanethiol, and phenyl isothiocyanate at concentrations ranging from 0.47 to 8.89 μg/L. Problems in the determination of organosulfur compounds related to considerable changes in composition of the effluents, increase in concentration of individual compounds and appearance of secondary pollutants during effluent treatment processes are also discussed. 相似文献
123.
Application of dispersive liquid–liquid microextraction and gas chromatography with mass spectrometry for the determination of oxygenated volatile organic compounds in effluents from the production of petroleum bitumen
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Grzegorz Boczkaj Patrycja Mako Andrzej Przyjazny 《Journal of separation science》2016,39(13):2604-2615
We present a new procedure for the determination of oxygenated volatile organic compounds in samples of postoxidative effluents from the production of petroleum bitumens using dispersive liquid–liquid microextraction and gas chromatography with mass spectrometry. The eight extraction parameters were optimized for 43 oxygenated volatile organic compounds. The detection limits obtained ranged from 0.07 to 0.82 μg/mL for most of the analytes, the precision was good (relative standard deviation below 2.91% at the 5 μg/mL level and 4.75% at the limit of quantification), the recoveries for the majority of compounds varied from 70.6 to 118.9%, and the linear range was wide, which demonstrates the usefulness of the procedure. The developed procedure was used for the determination of oxygenated volatile organic compounds in samples of raw postoxidative effluents and in effluents after chemical treatment. In total, 23 compounds at concentration levels from 0.37 to 32.95 μg/mL were identified in real samples. The same samples were also analyzed in the SCAN mode, which resulted in four more phenol derivatives being identified and tentatively determined. The studies demonstrated the need for monitoring volatile organic compounds content in effluents following various treatments due to the formation of secondary oxygenated volatile organic compounds. 相似文献
124.
Krzysztof Drwal Zuzanna Górska Patrycja Bończak Beata Krasnodębska-Ostręga 《Electroanalysis》2023,35(5):e202200397
The stripping voltammetry at HMDE is proposed for Cd and Pb (undesirable ingredients) determination in the natural brine (CCl >43 g L−1). Samples with so high salinity have to be significantly diluted. For ICP MS, a 105–6 times dilution is required, which disqualifies this method. The proposed procedure allows to determine Cd (0.001 μg L−1) and Pb (0.005 μg L−1) after only 100 times dilution. The thermal chloride stripping or isolation by Chelex 100 increase the quality of obtained data. The recovery study was performed. The LOQs are below recommendations related to the use of brines in balneology. 相似文献
125.
Frelek J Kowalska P Masnyk M Kazimierski A Korda A Woźnica M Chmielewski M Furche F 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(23):6732-6744
The biological activity of bicyclic beta-lactam antibiotics depends strongly on the absolute configuration of the bridgehead carbon atom. Frelek and co-workers proposed an empirical helicity rule relating the configuration of the bridgehead carbon atom to the sign of the 220 nm band in the electronic circular dichroism (CD) spectrum of beta-lactams. Here we use synthetic organic chemistry, CD spectroscopy, and time-dependent density functional theory (TDDFT) to investigate the validity of this structure-property relationship for eight model compounds. For conformationally flexible beta-lactams, substantial thermal effects are found which must be included in calculations. To this end, we combine TDDFT calculations of CD with full quantum-mechanical Born-Oppenheimer molecular dynamics (MD) simulations for the first time. The CD spectra are sampled with ground-state density functional trajectories of up to 60 ps. The MD simulations show a surprisingly high sensitivity of the CD to the molecular conformation. On the other hand, the relation between CD and thermally averaged structural parameters is much less complex. While the helicity rule does not seem to hold for individual conformers, it is confirmed by the calculations for seven out of eight systems studied if thermally averaged CD spectra and structures are considered. Since thermal effects on CD can be larger than typical inherent inaccuracies of TDDFT, our results emphasize the need for a systematic treatment of conformational dynamics in CD calculations even for moderately flexible systems. Temperature-dependent CD measurements are very useful for this purpose. Our results also suggest that CD spectroscopy may be used as a sensitive probe of conformational dynamics if combined with electronic structure calculations. 相似文献
126.
Biological activity of 5-aminolevulinic acid and its methyl ester after storage under different conditions 总被引:1,自引:0,他引:1
Kaliszewski M Kwasny M Juzeniene A Juzenas P Graczyk A Ma LW Iani V Mikolajewska P Moan J 《Journal of photochemistry and photobiology. B, Biology》2007,87(2):67-72
5-Aminolevulinic acid (ALA) is a natural precursor of protoporphyrin IX (PpIX) and heme in cells. Photodynamic therapy (PDT) utilizes a metabolic imbalance in cancer cells, leading to increased PpIX generation from exogenous ALA. Due to chemical instability of ALA in therapeutic concentrations at pH values larger than 5.0 and at high temperatures, it looses its activity by spontaneous dimerization to 2,5-dicarboxyethyl-3,6-dihydropyrazine (DHPY). ALA esters are now supplementing ALA in PDT, but little is known about their stability. We have studied the stability of ALA and its methyl ester (MAL) stored under different conditions (temperatures, pH values) by measuring their ability to generate PpIX. 100mM solutions of both compounds were found to be stable at pH 4 and at 4 degrees C. However, at pH 5.5 they lost almost 10% of the initial activity during 5days of storage at 4 degrees C. The fastest decay of ALA and MAL was seen at pH 7.4 and at 37 degrees C, and followed first order kinetics. At pH 7.4 and at 4 degrees C MAL lost its PpIX producing ability more slowly than at 37 degrees C. Our work shows that solutions should be prepared immediately before use and stored at low temperatures. The pH of stock solutions should not exceed 5. 相似文献
127.
Gordana Ćirić‐Marjanović Budimir Marjanović Patrycja Bober Zuzana Rozlívková Jaroslav Stejskal Miroslava Trchová Jan Prokeš 《Journal of polymer science. Part A, Polymer chemistry》2011,49(15):3387-3403
The oxidative polymerization of p‐phenylenediamine with silver nitrate by using various oxidant/monomer mole ratios in aqueous solutions of both acetic and nitric acid was studied experimentally and computationally. The produced micro/nanostructured conducting poly(p‐phenylenediamine)–silver composites, reaching the conductivities >104 S/cm, were characterized by conductivity and density measurements, gel permeation chromatography, transmission electron microscopy, UV–visible, FTIR, and Raman spectroscopies. The highest conductivity was 31,700 S/cm for poly(p‐phenylenediamine) base–silver (81.4 wt % Ag). The unexpected increase of conductivity after deprotonation of polymer component is discussed on the basis of interfacial electrical barriers and their removal. Theoretical study of the mechanism of p‐phenylenediamine oxidation has been based on the AM1 semi‐empirical quantum chemical computations of the heat of formation of the reaction intermediates, taking into account the influence of pH and solvation effects. Quantum chemical predictions of molecular structure of poly(p‐phenylenediamine) were correlated with spectroscopic findings. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
128.
Patrycja ?ak 《Journal of organometallic chemistry》2009,694(12):1903-1906
Efficient silylative coupling of linear vinyl-substituted oligo- and polysiloxanes with styrene in the presence of [RuHCl(CO)(PPh3)3] (1) and particularly [RuHCl(CO)(PCy3)2] (2) combined with copper(I) chloride is described. Treatment of styrene, with terminal or side vinyl group at siloxane skeleton catalyzed by [RuHCl(CO)(PCy3)2]/CuCl results in the quantitative and selective formation of respective silylative coupling products. 相似文献
129.
Microelectrode array fabricated in low temperature cofired ceramic (LTCC) technology 总被引:1,自引:0,他引:1
Patrycja Ciosek Konrad Zawadzki Dorota Stadnik Paweł Bembnowicz Leszek Golonka Wojciech Wróblewski 《Journal of Solid State Electrochemistry》2009,13(1):129-135
This work presents the development of a novel construction of an integrated microelectrode array. The device was fabricated
on a ceramic support, with the use of low temperature cofired ceramics technology. Model potassium-selective membranes were
applied on the surface of PdAg/AgCl electrodes formed on the ceramic substrate. The obtained microsensors exhibited very good
repeatability, reproducibility, and sensitivity. The array of microelectrodes covered with polymeric layers of various selectivities
was applied as an electronic tongue to differentiate between various diet supplements. 相似文献
130.
Dr. Renatus W. Sinkeldam Patrycja A. Hopkins Prof. Dr. Yitzhak Tor 《Chemphyschem》2012,13(14):3350-3356
Optimized facile syntheses and highly desirable spectroscopic properties of two isomorphic fluorescent pyrimidines, comprising a 1,2,4‐triazine motif conjugated to a thiophene ( 1 a ) or a furan ( 1 b ), are described. Although structurally related to their 5‐modified uridine counterparts, these modified 6‐aza‐uridines reveal dramatically improved fluorescence properties and a remarkable sensitivity to polarity and pH changes. The thiophene derivative 1 a has an absorption maximum around 335 nm, which upon excitation yields visible emission with a polarity‐sensitive maximum and fluorescence quantum yield ranging from 415 nm (Φ=0.8) to 455 nm (Φ=0.2) in dioxane and water, respectively. Nucleoside 1 a also displays susceptibility to acidity. Correlating emission intensity and solution pH yields a pKa value of 6.7–6.9, reasonably close to physiological pH values. The results illustrate that highly sought‐after fluorescence features (brightness and responsiveness) are not necessarily the trait of large fluorophores alone, but can be observed with probes that meet stringent isomorphic design criteria. 相似文献