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751.
Polystyrene (PS) decomposition in supercritical water (SCW) and in air was studied with the diamond anvil cell (DAC) technique coupled with microscopy and FTIR. Apparent concentrations were calculated by using digital imaging analysis. When PS + water systems (11.8–22.6 wt % PS) were rapidly heated at a rate of 2.3°C/s, the PS particle melted at 279.8–320.2°C. After formation of a globule at 409.3–452.5°C, the globule started to dissolve in color to yellow at 496.1°C. At 570.3°C and 742.5 MPa, solubility reached the maximum of 91.5 wt % (11.8 wt % PS). The soluble material was a styrenelike liquid, which was identified by IR after cooling. In isothermal runs at 400 and 450°C, two heterogeneous liquid phases consisting of water and decomposed PS were found. Styrenelike liquid products were identified after the reactions. PS decomposition stages in air consisted of melting, gas generation, liquid ring configuration, and finally yellow volatile products formation at 583.2°C. The results show conclusively that PS can be dissolved in SCW above 496.1°C and homogenous reaction is likely to occur above 570.3°C. Reactions in SCW at 400 and 450°C take place in heterogeneous liquid phases, while in the PS + air system, a formed liquid ring undergoes depolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3565–3577, 2001 相似文献
752.
Characterization of the coal fly ash for the purpose of improvement of industrial on-line measurement of unburned carbon content 总被引:1,自引:0,他引:1
The influence of selected properties of fly ash on the measurements of an on-line analyser was described. Fly ash studied in the research originated from the pulverized coal fired boiler. The samples were taken using an inspection method within a period of 3 months. Systematic observation of the properties of the ash allowed monitoring of the work of the industrial analyzer during a relatively long period of the power plant work. Samples of coal fly ash were examined for their chemical and physical properties. Morphology was analysed by scanning electron microscopy. Unburned carbon content in fly ash was determined by using loss-on-ignition (LOI) and thermogravimetry analysis (TGA). The particle size distribution of fly ash was examined. Correlation between laboratory and on-line industrial measurements of the unburned carbon content of ash was discussed. 相似文献
753.
The paper is to investigate seemingly a simple problem of THD interpretation in the wake of standards’ definitions and measurement methods. The consequences of application of various definitions of the considered factor are profoundly discussed on the basis of the real voltage waveforms registered in two different ship systems. Particularly, the results of determining of THD by means of various definitions are presented. Finally, the proposed amendment of related rules is provided. The aim is to overcome hitherto existing ambiguities. 相似文献
754.
Elzbieta Pawlowska Daniel Wysokiński Paulina Tokarz Agnieszka Piastowska-Ciesielska Joanna Szczepanska Janusz Blasiak 《International journal of molecular sciences》2014,15(9):16649-16664
The process of osteoblast differentiation is regulated by several factors, including RUNX2. Recent reports suggest an involvement of RUNX2 in DNA damage response (DDR), which is important due to association of differentiation with oxidative stress. In the present work we explore the influence of two RUNX2 modifiers, dexamethasone (DEX) and 1,25-dihydroxyvitamin D3 (1,25-D3), in DDR in differentiating MC3T3-E1 preosteoblasts challenged by oxidative stress. The process of differentiation was associated with reactive oxygen species (ROS) production and tert-butyl hydroperoxide (TBH) reduced the rate of differentiation. The activity of alkaline phosphatase (ALP), a marker of the process of osteoblasts differentiation, increased in a time-dependent manner and TBH further increased this activity. This may indicate that additional oxidative stress, induced by TBH, may accelerate the differentiation process. The cells displayed changes in the sensitivity to TBH in the course of differentiation. DEX increased ALP activity, but 1,25-D3 had no effect on it. These results suggest that DEX might stimulate the process of preosteoblasts differentiation. Finally, we observed a protective effect of DEX and 1,25-D3 against DNA damage induced by TBH, except the day 24 of differentiation, when DEX increased the extent of TBH-induced DNA damage. We conclude that oxidative stress is associated with osteoblasts differentiation and induce DDR, which may be modulated by RUNX2-modifiers, DEX and 1,25-D3. 相似文献
755.
Marcin Pajak Szymon Buchaniec Shinji Kimijima Janusz S. Szmyd Grzegorz Brus 《International Journal of Hydrogen Energy》2021,46(38):20183-20197
The presented research focuses on an optimization design of a catalyst distribution inside a small-scale methane/steam reforming reactor. A genetic algorithm was used for the multiobjective optimization, which included the search for an optimum of methane conversion rate and a minimum of the difference between highest and lowest temperatures in the reactor. For the sake of computational time, the maximal number of the segment with different catalyst densities was set to be thirty in this study. During the entire optimization process, every part of the reactor could be filled, either with a catalyst material or non-catalytic metallic foam. In both cases, the porosity and pore size was also specified. The impact of the porosity and pore size on the active reaction surface and permeability was incorporated using graph theory and three-dimensional digital material representation. Calculations start with the generation of a random set of possible reactors, each with a different catalyst distribution. The algorithm calls reforming simulation over each of the reactors, and after obtaining concentration and temperature fields, the algorithms calculated fitness function. The properties of the best reactors are combined to generate a new population of solutions. The procedure is repeated, and after meeting the coverage criteria, the optimal catalyst distribution was proposed. The paper is summarized with the optimal catalyst distribution for the given size and working conditions of the system. 相似文献
756.
Anna Makuch-Kocka Janusz Kocki Anna Brzozowska Jacek Bogucki Przemysaw Koodziej Bartosz J. Pachno Anna Bogucka-Kocka 《International journal of molecular sciences》2021,22(4)
The BIRC (baculoviral IAP repeat-containing; BIRC) family genes encode for Inhibitor of Apoptosis (IAP) proteins. The dysregulation of the expression levels of the genes in question in cancer tissue as compared to normal tissue suggests that the apoptosis process in cancer cells was disturbed, which may be associated with the development and chemoresistance of triple negative breast cancer (TNBC). In our study, we determined the expression level of eight genes from the BIRC family using the Real-Time PCR method in patients with TNBC and compared the obtained results with clinical data. Additionally, using bioinformatics tools (Ualcan and The Breast Cancer Gene-Expression Miner v4.5 (bc-GenExMiner v4.5)), we compared our data with the data in the Cancer Genome Atlas (TCGA) database. We observed diverse expression pattern among the studied genes in breast cancer tissue. Comparing the expression level of the studied genes with the clinical data, we found that in patients diagnosed with breast cancer under the age of 50, the expression levels of all studied genes were higher compared to patients diagnosed after the age of 50. We observed that in patients with invasion of neoplastic cells into lymphatic vessels and fat tissue, the expression levels of BIRC family genes were lower compared to patients in whom these features were not noted. Statistically significant differences in gene expression were also noted in patients classified into three groups depending on the basis of the Scarff-Bloom and Richardson (SBR) Grading System. 相似文献
757.
Jakub Stec Rafał Smulski Stanisław Nagy Krzysztof Szyszkiewicz-Warzecha Janusz Tomala Robert Filipek 《Ceramics International》2021,47(12):16538-16546
Permeability of experimental and standard micropore carbon materials, before and after the heat treatment at 1550 °C, was investigated using gas permeability measurements (GP) and mercury intrusion porosimetry (MIP). Permeability of both materials increased after the annealing. Experimental micropore carbon material was less permeable than standard one, both before and after the heat treatment. Measured gas permeabilities were compared with permeabilities determined based on MIP measurements using two different models: Hagen?Poiseuille and Carman?Kozeny equation. Using the inverse problem approach, for the first time Carman?Kozeny constant was determined for micropore carbon materials. Carman?Kozeny model gave more accurate results (i.e. close to gas permeability measurements) than Hagen?Poiseuille model. Performed investigations showed that mercury intrusion porosimetry might be alternative method to investigate infiltration resistance of low permeable materials. 相似文献
758.
759.
Janusz Blasiak Elzbieta Pawlowska Anna Sobczuk Joanna Szczepanska Kai Kaarniranta 《International journal of molecular sciences》2020,21(22)
Aging induces several stress response pathways to counterbalance detrimental changes associated with this process. These pathways include nutrient signaling, proteostasis, mitochondrial quality control and DNA damage response. At the cellular level, these pathways are controlled by evolutionarily conserved signaling molecules, such as 5’AMP-activated protein kinase (AMPK), mechanistic target of rapamycin (mTOR), insulin/insulin-like growth factor 1 (IGF-1) and sirtuins, including SIRT1. Peroxisome proliferation-activated receptor coactivator 1 alpha (PGC-1α), encoded by the PPARGC1A gene, playing an important role in antioxidant defense and mitochondrial biogenesis, may interact with these molecules influencing lifespan and general fitness. Perturbation in the aging stress response may lead to aging-related disorders, including age-related macular degeneration (AMD), the main reason for vision loss in the elderly. This is supported by studies showing an important role of disturbances in mitochondrial metabolism, DDR and autophagy in AMD pathogenesis. In addition, disturbed expression of PGC-1α was shown to associate with AMD. Therefore, the aging stress response may be critical for AMD pathogenesis, and further studies are needed to precisely determine mechanisms underlying its role in AMD. These studies can include research on retinal cells produced from pluripotent stem cells obtained from AMD donors with the mutations, either native or engineered, in the critical genes for the aging stress response, including AMPK, IGF1, MTOR, SIRT1 and PPARGC1A. 相似文献
760.
Mahato Dev K. Molak Andrzej Szeremeta Anna Z. Gruszka Irena Zajdel Pawel Pilch Michal Koperski Janusz 《Journal of Electroceramics》2019,42(3-4):136-146
Journal of Electroceramics - Double perovskite La2CrMnO6 ceramics was sintered using standard high temperature route in ambient air. The orthorhombic Pbnm cell characterized by a total disorder... 相似文献