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排序方式: 共有159条查询结果,搜索用时 281 毫秒
91.
Magorzata Smolio-Utrata Karolina A. Tarach Katarzyna Samson Mariusz Gackowski Ewa Madej Jzef Korecki Grzegorz Mordarski Micha
liwa Sebastian Jarczewski Jerzy Podobiski Piotr Kutrowski Jerzy Datka Dorota Rutkowska-Zbik Kinga Gra-Marek 《International journal of molecular sciences》2022,23(10)
The commercially available zeolite HY and its desilicated analogue were subjected to a classical wet impregnation procedure with NH4VO3 to produce catalysts differentiated in acidic and redox properties. Various spectroscopic techniques (in situ probe molecules adsorption and time-resolved propane transformation FT-IR studies, XAS, 51V MAS NMR, and 2D COS UV-vis) were employed to study speciation, local coordination, and reducibility of the vanadium species introduced into the hierarchical faujasite zeolite. The acid-based redox properties of V centres were linked to catalytic activity in the oxidative dehydrogenation of propane. The modification of zeolite via caustic treatment is an effective method of adjusting its basicity—a parameter that plays an important role in the ODH process. The developed mesopore surface ensured the attachment of vanadium species to silanol groups and formation of isolated (SiO)2(HO)V=O and (SiO)3V=O sites or polymeric, highly dispersed forms located in the zeolite micropores. The higher basicity of HYdeSi, due to the presence of the Al-rich shell, aided the activation of the C−H bond leading to a higher selectivity to propene. Its polymerisation and coke formation were inhibited by the lower acid strength of the protonic sites in desilicated zeolite. The Al-rich shell was also beneficial for anchoring V species and thus their reducibility. The operando UV-vis experiments revealed higher reactivity of the bridging oxygens V-O-V over the oxo-group V=O. The (SiO)3V=O species were found to be ineffective in propane oxidation when temperature does not exceed 400 °C. 相似文献
92.
Kinga Jaworska Wojciech Kopacz Mateusz Koper Mateusz Szudzik Marta Gawry-Kopczyska Marek Konop Tomasz Hutsch Dawid Chabowski Marcin Ufnal 《International journal of molecular sciences》2022,23(11)
Evidence suggests that microbiota-derived metabolites, including short-chain fatty acids (SCFAs) and trimethylamine-oxide (TMAO), affect the course of diabetic multiorgan pathology. We hypothesized that diabetes activates the intestinal renin–angiotensin system (RAS), contributing to gut pathology. Twelve-week-old male rats were divided into three groups: controls, diabetic (streptozotocin-induced) and diabetic treated with enalapril. Histological examination and RT-qPCR were performed to evaluate morphology and RAS expression in the jejunum and the colon. SCFA and TMAO concentrations in stools, portal and systemic blood were evaluated. In comparison to the controls, the diabetic rats showed hyperplastic changes in jejunal and colonic mucosa, increased plasma SCFA, and slightly increased plasma TMAO. The size of the changes was smaller in enalapril-treated rats. Diabetic rats had a lower expression of Mas receptor (MasR) and angiotensinogen in the jejunum whereas, in the colon, the expression of MasR and renin was greater in diabetic rats. Enalapril-treated rats had a lower expression of MasR in the colon. The expression of AT1a, AT1b, and AT2 receptors was similar between groups. In conclusion, diabetes produces morphological changes in the intestines, increases plasma SCFA, and alters the expression of renin and MasR. These alterations were reduced in enalapril-treated rats. Future studies need to evaluate the clinical significance of intestinal pathology in diabetes. 相似文献
93.
Gabriella Szalai Mihly Dernovics Orsolya Kinga Gondor Judit Tajti Anna Borbla Molnr Magdalena Anna Lejmel Svetlana Misheva Viktria Kovcs Magda Pl Tibor Janda 《International journal of molecular sciences》2022,23(14)
The wheat semi-dwarfing genes Rht (Reduced height) are widely distributed among the contemporary wheat varieties. These genes also exert pleiotropic effects on plant tolerance towards various abiotic stressors. In this work, frost tolerance was studied in three near-isogenic lines of the facultative variety ‘April Bearded’ (AB), carrying the wild type allele Rht-B1a (tall phenotype), and the mutant alleles Rht-B1b (semi-dwarf) and Rht-B1c (dwarf), and was further compared with the tolerance of a typical winter type variety, ‘Mv Beres’. The level of freezing tolerance was decreasing in the order ‘Mv Beres’ > AB Rht-B1a > AB Rht-B1b > AB Rht-B1c. To explain the observed differences, cold acclimation-related processes were studied: the expression of six cold-related genes, the phenylpropanoid pathway, carbohydrates, amino acids, polyamines and compounds in the tricarboxylic acid cycle. To achieve this, a comprehensive approach was applied, involving targeted analyses and untargeted metabolomics screening with the help of gas chromatography/liquid chromatography—mass spectrometry setups. Several cold-related processes exhibited similar changes in these genotypes; indeed, the accumulation of eight putrescine and agmatine derivatives, 17 flavones and numerous oligosaccharides (max. degree of polymerization 18) was associated with the level of freezing tolerance in the ‘April Bearded’ lines. In summary, the mutant Rht alleles may further decrease the generally low frost tolerance of the Rht-B1a, and, based on the metabolomics study, the mechanisms of frost tolerance may differ for a typical winter variety and a facultative variety. Present results point to the complex nature of frost resistance. 相似文献
94.
Katarzyna Reczyńska Dipesh Khanal Kinga Pielichowska Elżbieta Pamuła Wojciech Chrzanowski 《Lipids》2020,55(2):117-126
The impact of saturated fatty acids (FA) on viability and properties of malignant and nonmalignant cells has not been studied in detail so far. The present study was aimed at evaluation of the influence of saturated FA (10:0–18:0) on malignant (A459) and nonmalignant (BEAS-2B) human lung epithelial cells. FA strongly affected A549 cells, but not BEAS-2B cells. Viability of A549 cells incubated with 14:0–18:0 was decreased by 53–91% as compared to untreated cells. Cell membrane stiffness in those cells as measured by atomic force microscopy was also reduced. Median value of apparent Young's modulus of untreated A549 cell membrane was 16.9 kPa and it decreased to 8.9 kPa for cells incubated with 14:0. Viability and mechanical properties of BEAS-2B cells were not altered by presence of FA. Those surprising discrepancies can be related to the differences in FA uptake rate. A549 cells were found to incorporate higher amount of FA and this corresponded to decrease in cell membrane stiffness and reduced cell viability. The performed studies showed that saturated FA have distinct influence on various types of cells, which may be exploited in development of the advanced lipid drug delivery systems. 相似文献
95.
Depression coexists with epilepsy, worsening its course. Treatment of the two diseases enables the possibility of interactions between antidepressant and antiepileptic drugs. The aim of this review was to analyze such interactions in one animal seizure model—the maximal electroshock (MES) in mice. Although numerous antidepressants showed an anticonvulsant action, mianserin exhibited a proconvulsant effect against electroconvulsions. In most cases, antidepressants potentiated or remained ineffective in relation to the antielectroshock action of classical antiepileptic drugs. However, mianserin and trazodone reduced the action of valproate, phenytoin, and carbamazepine against the MES test. Antiseizure drug effects were potentiated by all groups of antidepressants independently of their mechanisms of action. Therefore, other factors, including brain-derived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) modulation, should be considered as the background for the effect of drug combinations. 相似文献
96.
Kinga Góra-Marek 《Topics in Catalysis》2009,52(8):1023-1029
The process of reducing Co ions in zeolite CoZSM-5 by NO, H2 and CO, as well as of oxidizing them by O2 was studied by IR spectroscopy with CO as the probe molecule for Co2+ and NO as the probe for Co3+. Two zeolites of different Co status were used: in the first, Co2+ ions were localized mostly in cation exchange positions, and in the second most of the Co2+ occurred in the form of CoO and oxide-like clusters. IR studies evidenced that NO reduced some Co3+ to Co2+ already at room temperature, and also reduced some Co2+ to lower oxidation states (probably Co+) at 670 and 1070 K. Only Co2+ in exchange positions could be reduced with NO. The treatment of zeolite CoZSM-5 with H2 or with CO at 670 and 1070 K made the reduction of Co3+ to Co2+ (the contribution of Co3+ decreased and the contribution of Co2+ increased). IR studies illustrated that the most electron-acceptor Co3+ (characterized by a high frequency Co3+–NO band) were transformed, by reduction, into the most electron-acceptor Co2+ (characterized by a high frequency Co2+–CO band). The treatment of zeolite CoZSM-5 with oxygen at 670–1070 K resulted in the oxidation of Co2+ to Co3+ (the contribution of Co2+ decreased while the contribution of Co3+ increased). 相似文献
97.
Carlos Sainz Alexandra Dinu Kinga Szacsvai Luis Santiago Quindós 《The Science of the total environment》2009,407(15):4452-4460
Radon and radon progeny are present indoors, in houses and others dwellings, representing the most important contribution to dose from natural sources of radiation. Most studies have demonstrated an increased risk of lung cancer at high concentration of radon for both smokers and nonsmokers. The work presents a comparative analysis of the radon exposure data in the two radon-prone areas, ?tei, Transylvania, (Romania), in the near of old Romanian uranium mines and in the granitic area of Torrelodones town, Sierra de Guadarrama (Spain). Measurements of indoor radon were performed in 280 dwellings (Romania) and 91 dwellings (Spain) by using nuclear track detectors, CR 39. The highest value measured in ?tei area was 2650 Bq m− 3 and 366 Bq m− 3 in the Spanish region. The results are computed with the BEIR VI report estimates using the age-duration model at an exposure rate below 2650 Bq m− 3. We used the EC Radon Software to calculate the lifetime lung cancer death risks for individuals groups in function of attained age, radon exposures and tobacco consumption. A total of 233 lung cancer deaths were observed in the ?tei area for a period of 13 years (1994-2006), which is 116.82% higher than expected from the national statistics. In addition, the number of deaths estimated for the year 2005 is 28, which is worth more than 2.21 times the amount expected by authorities. In comparison, for Torrelodones was rated a number of 276 deaths caused by lung cancer for a period of 13 years, which is 2.09 times higher than the number expected by authorities. For the year 2005 in the Spanish region were reported 32 deaths caused by pulmonary cancer, the number of deaths exceeding seen again with a factor of 2.10 statistical expectations. This represents a significantly evidence that elevated risk can strongly be associated with cumulated radon exposure. 相似文献
98.
99.
100.
Kinga Zór Katarzyna Dymek Roberto Ortiz Audrey M. Faure Ebru Saatci Lo Gorton Ronald Bardsley Mihaela Nistor 《Food chemistry》2012
A method is described for quantification of the beef tenderness marker, calpastatin, in meat samples by amperometric detection. Using a novel bovine recombinant partial calpastatin protein as standard antigen a low detection limit of 0.2 ng/mL was achieved. The influence of the complex matrix was minimised by heat pretreatment and dilution of the samples prior to detection of calpastatin. The relative error between the direct sample measurement and standard addition methods was 5.89%, confirming the accuracy of the developed amperometric immunoassay. 相似文献