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751.
Radosław Podsiadły Jolanta Sokołowska Jolanta Kolińska Aleksandra Grzelakowska 《Coloration Technology》2017,133(6):498-505
Novel dyes based on the benzo[a]quinoxalino[2,3‐c]phenazine skeleton and necessary intermediates (benzo[a]phenazine‐5,6‐diones) were synthesized. The heterocyclic dyes and benzo[a]phenazine‐5,6‐diones were characterized using 1H nuclear magnetic resonance (NMR) spectroscopy and chemical ion (CI) mass spectrometry. Their spectral properties, such as absorption and emission spectra and fluorescence quantum yield, were also measured. Experimental results demonstrated that photolysis of benzo[a]quinoxalino[2,3‐c]phenazine dyes in 2‐propanol and cyclohexene oxide leads to dihydro derivatives. The same product is formed during irradiation of dye/iodonium salt photoredox pairs in monomers. These compounds absorb incident light at longer wavelength and act as in situ sensitizers. Thus, when a composition was irradiated with a xenon lamp through a 395 cutoff filter, higher conversion was achieved than under monochromatic light. 相似文献
752.
Conjugation of a Dipicolyl Chelate to Polypeptide Conjugates Increases Binding Affinities for Human Serum Albumin and Survival Times in Human Serum 下载免费PDF全文
Aleksandra Balliu Prof. Lars Baltzer 《Chembiochem : a European journal of chemical biology》2017,18(14):1408-1414
The affinity for human serum albumin (HSA) of a series of 2–5 kDa peptides covalently linked to 3,5‐bis[[bis(2‐pyridylmethyl)amino]methyl]benzoic acid, a dipicolyl chelator with micromolar affinity for Zn2+, was found by surface plasmon resonance to increase in the presence of 1 μm ZnCl2 at physiological pH. The dependence on polypeptide hydrophobicity was found to be minor, thus suggesting that the conjugates bound to the metal‐binding site and not to the fatty‐acid‐binding site. The affinity of the conjugates increased strongly with the positive charge of the polypeptides, thus implicating the negatively charged protein surface surrounding the metal‐binding site. The survival times of the peptides in human serum were extended as a consequence of stronger binding to HSA, thus suggesting that Zn2+‐chelating agents might provide a general route to increased survival time of peptides in serum in therapeutic and diagnostic applications without significantly increasing their molecular weights. 相似文献
753.
An analytical calculation method for the estimation of the contents of alkyl aryl ether bonds (α-O-4 and β-O-4) in lignin was developed. In the framework of the method, Alkyl–O–Aryl type bonds are described as coupled phenolic hydroxyls (OHphen). The method is based on the balance equation including the free and coupled OHphen contents in dissolved and residual lignins, on the one hand, and their respective contents in native lignin, on the other. The free OHphen content is calculated on the basis of the OHphen contents of dissolved and residual lignin, determined by the aminolysis method in the course of kraft cooking of softwood. The calculation results for soluble lignin preparations are in good agreement with the 13C NMR (nuclear magnetic resonance) spectral data for the solutions. The content of Alkyl–O–Aryl bonds in native softwood (pine, spruce) lignin was estimated at 79/100 PPU (phenylpropane unit). In isolated lignin preparations, the contents of these bonds decrease in the sequence: Freudenberg lignin (71/100 PPU)> Bjorkman lignin (61/100 PPU)> Pepper lignin (44/100 PPU). Dissolved alkaline lignin still contains small amounts of Alkyl–O–Aryl bonds (36/100 PPU in soda lignin and an average of 23/100 PPU in soda-AQ lignin, kraft lignin, and kraft-AQ lignin). Residual lignin which represents the fraction of native lignin with inter-unit bonds resistant to kraft pulping contains 66/100 PPU of such bonds. A relatively high content of Alkyl–O–Aryl bonds (61/100 PPU) is preserved in technical hydrolysis lignins. 相似文献
754.
Atomic force microscopy has been applied for measuring the nanomechanical characteristics of poly(methyl methacrylate) thin films containing 5% photoinitiator (Irgacure 651). The nanohardness, Young's modulus, and adhesion to AFM tip have been evaluated for the unexposed samples and after UV‐irradiation. Additionally, FTIR spectroscopy and differential scanning calorimetry (DSC) have been applied to explain the observed changes in nanomechanical properties. It was found that the exposure to ultraviolet changed the nanomechanical properties of polymer because of photo‐oxidative degradation and relaxation processes. These studies lead to the conclusion that the applied photoinitiator has no noticeable effect on nanohardness and Young modulus during PMMA irradiation, but efficiently participates in polymer photo‐oxidation increasing the surface hydrophilicity and adhesion to Si3N4. Moreover, the initiator hampers the relaxation of PMMA macromolecules, what was proved by DSC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
755.
This article evaluates the effect of air drying, freeze drying, and 24-month storage at 4 and 20 ° C on unblanched and blanched Boletus edulis . Water content and activity were lower in freeze-dried mushrooms than in air-dried mushrooms, whereas rehydration capacity showed the opposite tendency. Drying resulted in substantial losses of the following antioxidants: total flavonoids (4–7%), vitamin C (2–36%), β-carotene (26–32%), and total tocopherols (72–81%); total polyphenols increased during air drying (7–17%) and decreased during freeze drying (5–7%). Antioxidant activity increased 1–33% during drying. Storage led to further changes in the quality of dried mushrooms. After 24 months, no vitamin C or tocopherols were detected, and water content and activity were moderately high. 相似文献
756.
Aleksandra Kapuścik Dr. Pavel Hrouzek Dr. Marek Kuzma Simona Bártová Dr. Petr Novák Dr. Jouni Jokela Maren Pflüger Dr. Andreas Eger Dr. Harald Hundsberger Dr. Jiří Kopecký 《Chembiochem : a European journal of chemical biology》2013,14(17):2329-2337
Aeruginosin‐865 (Aer‐865), isolated from terrestrial cyanobacterium Nostoc sp. Luke?ová 30/93, is the first aeruginosin‐type peptide containing both a fatty acid and a carbohydrate moiety, and is the first aeruginosin to be found in the genus Nostoc. Mass spectrometry, chemical and spectroscopic analysis as well as one‐ and two‐dimensional NMR and chiral HPLC analysis of Marfey derivatives were applied to determine the peptidic sequence: D ‐Hpla, D ‐Leu, 5‐OH‐Choi, Agma, with hexanoic and mannopyranosyl uronic acid moieties linked to Choi. We used an AlphaLISA assay to measure the levels of proinflammatory mediators IL‐8 and ICAM‐1 in hTNF‐α‐stimulated HLMVECs. Aer‐865 showed significant reduction of both: with EC50 values of (3.5±1.5) μg mL?1 ((4.0±1.7) μM ) and (50.0±13.4) μg mL?1 ((57.8±15.5) μM ), respectively. Confocal laser scanning microscopy revealed that the anti‐inflammatory effect of Aer‐865 was directly associated with inhibition of NF‐κB translocation to the nucleus. Moreover, Aer‐865 did not show any cytotoxic effect. 相似文献
757.
Eugene Olevsky Tesfaye Tadesse Molla Henrik Lund Frandsen Rasmus Bjørk Vincenzo Esposito De Wei Ni Aleksandra Ilyina Nini Pryds 《Journal of the American Ceramic Society》2013,96(8):2657-2665
Theoretical analyses of shrinkage and distortion kinetics during sintering of bilayered porous structures are carried out. The developed modeling framework is based on the continuum theory of sintering; it enables the direct assessment of the cofiring process outcomes and of the impact of process controlling parameters. The derived “master sintering curve”‐type solutions are capable of describing and optimizing the generic sintering shrinkage and distortion kinetics for various material systems. The approach utilizes the material‐specific parameters, which define the relative kinetics of layer shrinkages such as the relative intensity of sintering, and employs the conversion between real and specific times of sintering. A novel methodology is also developed for the determination of the ratio of the shear viscosities of the layer's fully dense materials. This new technique enables the determination of all input parameters necessary for modeling sintering of bilayers using experimental techniques similar to optical dilatometry applied to each individual layer and to a symmetric trilayered porous structure based on the two‐layer materials utilized in the bilayered system. Examples of sintering different porous bilayered systems are presented to justify the capability of the model in predicting and optimizing sintering kinetics. 相似文献
758.
Aleksandra Matuszyk Piotr Ceranowicz Zygmunt Warzecha Jakub Cieszkowski Dagmara Ceranowicz Krystyna Ga??zka Joanna Bonior Jolanta Jaworek Krzysztof Bartu? Krzysztof Gil Rafa? Olszanecki Artur Dembiński 《International journal of molecular sciences》2016,17(9)
Previous studies have shown that ghrelin reduces colonic inflammation induced by trinitrobenzene sulfonic acid and dextran sodium sulfate. In the present study we determined the effect of treatment with ghrelin on the course of acetic acid-induced colitis in rats. Rectal administration of 3% acetic acid solution led to induction of colitis in all animals. Damage of the colonic wall was accompanied by an increase in mucosal concentration of pro-inflammatory interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well mucosal activity of myeloperoxidase. Moreover, induction of colitis led to a reduction in colonic blood flow and DNA synthesis. Administration of ghrelin after induction of colitis led to faster regeneration of the colonic wall and reduction in colonic levels of IL-1β, TNF-α, and myeloperoxidase. In addition, treatment with ghrelin improved mucosal DNA synthesis and blood flow. Our study disclosed that ghrelin exhibits a strong anti-inflammatory and healing effect in acetic acid-induced colitis. Our current observation in association with previous findings that ghrelin exhibits curative effect in trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis suggest that therapeutic effect of ghrelin in the colon is universal and independent of the primary cause of colitis. 相似文献
759.
Mihajlo Gajic Dr. Damijan Knez Dr. Izidor Sosič Prof. Janez Mravljak Anže Meden Dr. Urban Košak Luisa Leitzbach Sven George Dr. Bettina Hofmann Dr. Aleksandra Zivkovic Prof. Dieter Steinhilber Prof. Holger Stark Prof. Stanislav Gobec Prof. Andrija Smelcerovic Prof. Marko Anderluh 《ChemMedChem》2022,17(5):e202100694
A library of 31 butyrylcholinesterase (BChE) and cathepsin B (CatB) inhibitors was screened in vitro for inhibition of deoxyribonuclease I (DNase I). Compounds 22 , 8 and 7 are among the most potent synthetic non-peptide DNase I inhibitors reported to date. Three 8-hydroxyquinoline analogues inhibited both DNase I and BChE with IC50 values below 35 μM and 50 nM, respectively, while two nitroxoline derivatives inhibited DNase I and Cat B endopeptidase activity with IC50 values below 60 and 20 μM. Selected derivatives were screened for various co-target binding affinities at dopamine D2 and D3, histamine H3 and H4 receptors and inhibition of 5-lipoxygenase. Compound 8 bound to the H3 receptor and is highlighted as the most promising multifunctional ligand with a favorable pharmacokinetic profile and one of the most potent non-peptide DNase I inhibitors. The present study demonstrates that 8-hydroxyquinoline is a structural fragment critical for DNase I inhibition in the presented series of compounds. 相似文献
760.
Effect of Hydrothermal Treatment of Rapeseed on Antioxidant Capacity of the Pressed Rapeseed Oil 总被引:1,自引:0,他引:1
Aleksandra Szydłowska-Czerniak György Karlovits Ágnes Sosna-Sárdi Csilla Dianoczki Edward Szłyk 《Journal of the American Oil Chemists' Society》2009,86(8):817-825
Response surface methodology (RSM) was used to evaluate the quantitative effects of two independent variables, rapeseed moisture
content and conditioning temperature, on the antioxidant capacity (AC) and total phenolic (TPC), tocopherol (TTC), and phosphorus
contents (PC) in the pressed rapeseed oils. The mean AC results for the crude rapeseed oils ranged from 199.8 to 947.2 μmolTE/100 g.
TPC and PC in the crude rapeseed oils correlated significantly (P < 0.01) and positively with AC of oils (R
2 = 0.9498 and 0.4396, respectively). The experimental results of AC, TPC, and PC were close to the predicted values calculated
from the polynomial response surface model equations (R
2 = 0.9801, 0.9747 and 0.9165, respectively). The effect of oil processing temperature on AC and TPC was about 1.5 times greater
than the effect of moisture level in rapeseed. 相似文献