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排序方式: 共有1306条查询结果,搜索用时 15 毫秒
991.
Mikhail A. Vorotyntsev Magdalena Skompska Magdalena Graczyk Jürgen Heinze Jerome Goux Pierre Le Gendre Claude Moise 《Journal of Solid State Electrochemistry》2008,12(4):421-435
Three tantalocene dichloride complexes, Cp*(Cp-R)Ta(IV)Cl2, with one pentamethylated cyclopentadienyl ligand, Cp* = η5–C5Me5, Me = CH3, and one monosubstituted cyclopentadienyl ligand, Cp-R, Cp = η5–C5H5, R = H, SiMe3 or (CH2)3NC4H4, have been studied in acetonitrile solutions with cyclic voltammetry in the ranges of the Ta(IV) oxidation to Ta(V) or of
its reduction to Ta(III). The former transition is reversible, while the latter one gives an irreversible wave due to the
dissociation of the reduced complex with the loss of one chloride ligand. The redox transformation from the initial state
of complex Cp*CpSiMe3TaCl2 to its oxidized state, Cp*CpSiMe3TaCl2
+, and back was monitored by spectroelectrochemical measurements in a thin-layer acetonitrile solution. Kinetic data for the
evolution of the UV-visible spectrum of the system in the course of the double potential step experiment were treated on the
basis of two theoretical models as the reactant diffusion across the solution layer without or with taking into account ohmic
losses. The values of the diffusion coefficients of the complex in its initial and oxidized (cationic) states have been estimated.
It was demonstrated that this complex in each of two oxidation states, Ta(IV) or Ta(V), is represented by a single molecular
form. An attempt to deposit a conducting polymer film by oxidation of the tantalocene complex containing a pyrrole group attached
to the Cp ring, Cp*Cp(CH2)3PyTaCl2, led to a thin insulating layer at the electrode surface because of an inhibiting effect of chloride anions.
相似文献
Mikhail A. VorotyntsevEmail: |
992.
Przemysaw Siejak Wojciech Smuek Farahnaz Fathordobady Anna Grygier Hanna Maria Baranowska Magdalena Rudziska ukasz Masewicz Magorzata Jarzbska Piotr T. Nowakowski Aleksandra Makiej Pardis Kazemian Pawe Drobnik Barbara Stachowiak Maciej Jarzbski Anubhav Pratap-Singh 《Molecules (Basel, Switzerland)》2021,26(10)
To meet the growing interest in natural antibacterial agents, we evaluated the physicochemical and biological properties of the folk medicine known as “five thieves’ oil” (Polish name: olejek pięciu złodziei). Five thieves’ oil consists of a mixture of five oils: rosemary, lemon, clove, eucalyptus, and cinnamon. In this study, we performed gas chromatography, FTIR, and UV–vis spectroscopic analysis, as well as L-a-b color tests, contact angle determination, and surface tension determination. To verify its antibacterial activity, the metabolic activity and changes in cell membrane permeability of bacteria of the genus Pseudomonas were studied. As a result, it was found that among the constituent oils, the oils of clove and cinnamon were the least volatile and, at the same time, had the strongest antibacterial activity. However, a mix of all the oils also showed comparable activity, which was even more pronounced for the oils after 4 weeks of aging. This effect can be linked to the high content of terpene derivatives such as eugenol and cinnamaldehyde, which can cause changes in bacterial membrane permeability, affecting cell activity and survival. This study is the first to characterize the constituents of the popular folk medicine five thieves’ oil, confirming and explaining its strong antibacterial activity, thus constituting a significant contribution to contemporary health education. 相似文献
993.
Zeolite Y is one of the earliest known and most widely used synthetic zeolites. Many experimental investigations verify the valuable ion exchange capability of this zeolite. In this study, we assessed the effects of ion exchange on its vibrational spectra. We applied classical lattice dynamics methods for IR and Raman intensity calculations. Computed spectra of optimized zeolite Y structures with different cations were compared with experimental data. The spectra obtained in this study are in agreement with previous experimental and computational studies on zeolites from the faujasite group. 相似文献
994.
Magdalena Kusaczuk Monika Naumowicz Rafa Krtowski Bartosz Cukierman Marzanna Cechowska-Pasko 《Molecules (Basel, Switzerland)》2021,26(4)
Osteoarthritis (OA) is considered one of the most common arthritic diseases characterized by progressive degradation and abnormal remodeling of articular cartilage. Potential therapeutics for OA aim at restoring proper chondrocyte functioning and inhibiting apoptosis. Previous studies have demonstrated that tauroursodeoxycholic acid (TUDCA) showed anti-inflammatory and anti-apoptotic activity in many models of various diseases, acting mainly via alleviation of endoplasmic reticulum (ER) stress. However, little is known about cytoprotective effects of TUDCA on chondrocyte cells. The present study was designed to evaluate potential effects of TUDCA on interleukin-1β (IL-1β) and tunicamycin (TNC)-stimulated NHAC-kn chondrocytes cultured in normoxic and hypoxic conditions. Our results showed that TUDCA alleviated ER stress in TNC-treated chondrocytes, as demonstrated by reduced CHOP expression; however, it was not effective enough to prevent apoptosis of NHAC-kn cells in either normoxia nor hypoxia. However, co-treatment with TUDCA alleviated inflammatory response induced by IL-1β, as shown by down regulation of Il-1β, Il-6, Il-8 and Cox2, and increased the expression of antioxidant enzyme Sod2. Additionally, TUDCA enhanced Col IIα expression in IL-1β- and TNC-stimulated cells, but only in normoxic conditions. Altogether, these results suggest that although TUDCA may display chondoprotective potential in ER-stressed cells, further analyses are still necessary to fully confirm its possible recommendation as potential candidate in OA therapy. 相似文献
995.
Anna Pierzchliska Magdalena Kwaniak-Butowska Jarosaw Sawek Marek Dro
dzik Monika Biaecka 《Molecules (Basel, Switzerland)》2021,26(6)
Dementia is one of the most disabling non-motor symptoms in Parkinson’s disease (PD). Unlike in Alzheimer’s disease, the vascular pathology in PD is less documented. Due to the uncertain role of commonly investigated metabolic or vascular factors, e.g., hypertension or diabetes, other factors corresponding to PD dementia have been proposed. Associated dysautonomia and dopaminergic treatment seem to have an impact on diurnal blood pressure (BP) variability, which may presumably contribute to white matter hyperintensities (WMH) development and cognitive decline. We aim to review possible vascular and metabolic factors: Renin-angiotensin-aldosterone system, vascular endothelial growth factor (VEGF), hyperhomocysteinemia (HHcy), as well as the dopaminergic treatment, in the etiopathogenesis of PD dementia. Additionally, we focus on the role of polymorphisms within the genes for catechol-O-methyltransferase (COMT), apolipoprotein E (APOE), vascular endothelial growth factor (VEGF), and for renin-angiotensin-aldosterone system components, and their contribution to cognitive decline in PD. Determining vascular risk factors and their contribution to the cognitive impairment in PD may result in screening, as well as preventive measures. 相似文献
996.
We prove a noncommutative version of the John-Nirenberg theorem for nontracial filtrations of von Neumann algebras. As an application, we obtain an analogue of the classical large deviation inequality for elements of the associated space.
997.
Magdalena Buszewska-Forajta Katarzyna Rafińska Boguslaw Buszewski 《Journal of separation science》2022,45(7):1345-1361
Matrix-assisted laser desorption/ionization - imaging mass spectrometry is an alternative tool, which can be implemented in order to obtain and visualize the “omic” signature of tissue samples. Its application to clinical study enables simultaneous imaging-based morphological observations and mass spectrometry analysis. Application of fully informative material like tissue allows obtaining the complex and unique profile of analyzed samples. This knowledge leads to diagnosing disease, studying the mechanism of cancer development, selecting the potential biomarkers as well as correlating obtained images with prognosis. Nevertheless, it is worth noticing that this method is found to be objective but the result of the analysis is mainly influenced by the sample preparation protocol, including the collection of biological material, its preservation, and processing. However, the application of this approach requires a special sample preparation procedure. The main goal of the study is to present the current knowledge on the clinical application of matrix-assisted laser desorption/ionization with imaging mass spectrometry in cancer research, with particular emphasis on the sample preparation step. For this purpose, several protocols based on cryosections and formalin-fixed paraffin-embedded tissue were compiled and compared, taking into account the measured metabolites of potential diagnostic importance for a given type of cancer. 相似文献
998.
Shcharbin D Mazur J Szwedzka M Wasiak M Palecz B Przybyszewska M Zaborski M Bryszewska M 《Colloids and surfaces. B, Biointerfaces》2007,58(2):286-289
Binding of Cd2+ by PAMAM 4.5 dendrimer was studied by equilibrium dialysis, isothermal titration calorimetry and zeta-potential measurement. The following binding parameters were obtained: n = 23.8 ± 9.5, Kb = 4.7 ± 0.9 × 103 in water; and n = 41.3 ± 13.4, Kb = 2.1 ± 0.8 × 103 in 0.15 mol/l phosphate-buffered saline. The location of the bound Cd2+ is discussed. The interactions between bovine serum albumin, PAMAM 4.5 dendrimer and cadmium were analyzed using fluorescence and equilibrium dialysis. The competition between Cd2+ binding to BSA and PAMAM 4.5 dendrimer was investigated. It is proposed that PAMAM 4.5 dendrimer could be successfully used for extracting Cd2+ from aqueous solutions (environmental protection). 相似文献
999.
Wanda Ziemkowska Magdalena Metelska Romana Anulewicz-Ostrowska 《Journal of organometallic chemistry》2008,693(3):369-373
A reaction of Me3Al with 2,2′-methylene-p-chloro-bisphenol in Et2O yielded Me5Al3[OC6H3(Cl)CH2C6H3(Cl)O]2 (1). Compound 1 reacted with 2,2′-di(hydroxymethyl)biphenyl to form Me3Al3[OC6H3(Cl)CH2C6H3(Cl)O](OCH2C12H8CH2O)2 (2) bearing two kinds of diolate ligands. Compound 2 was structurally characterised. 相似文献
1000.