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排序方式: 共有435条查询结果,搜索用时 15 毫秒
111.
Joanna Mastalska-Popławska Kornelia Kadac Piotr Izak Marcin Gierej Agata Stempkowska Zuzanna Góral 《应用聚合物科学杂志》2021,138(9):49914
The article presents results of the research on the influence of graphite/kaolin and graphite/titanium oxide systems on thermal properties, intumescence degree and the integrity of the structure of intumescent protective films based on epoxy resins for steel. The TG/DTG/DSC analysis showed that graphite/kaolin system shifted the decomposition reaction of epoxy resin towards higher temperatures, even by about 30°C. Fire endurance tests and the SEM analysis confirmed these results because more thermally resistant (T500°C reached after 37.5 min for 1.1 coating thickness), swollen (about 20 times) and homogeneous coatings were obtained. The presented results suggest that ceramic fire retardants can successfully cooperate with organic components in intumescent protective coatings for steel elements. 相似文献
112.
Barbara M. Moskal Catherine Skokan Laura Kosbar Agata Dean Caron Westland Heidi Barker Que N. Nguyen Jennifer Tafoya 《工程教育杂志》2007,96(3):173-189
Over the last four years, a series of outreach programs have been offered through the Colorado School of Mines to middle school teachers from eleven school districts in the State of Colorado in the United States. Each of these programs is designed to illustrate through hands‐on activities the application of mathematics to science and engineering. Each also has an academic year follow‐up such that a faculty member, an expert teacher, or a graduate student assists the teachers in the classroom. An expected outcome of this effort is the improvement of instruction in mathematics and science in the participating middle schools; an unexpected outcome has been the impact of these projects on the culture of the participating schools, both middle schools and university. Based on our assessment efforts, this article describes the qualitative and quantitative outcomes of this sequence of projects on middle school students, teachers, graduate students, professors, and college curriculum. 相似文献
113.
Md. Sirajul Islam Taikan Oki Shinjiro Kanae Naota Hanasaki Yasushi Agata Kei Yoshimura 《Water Resources Management》2007,21(1):19-33
A 0.5-degree grid-based assessment of the scarcity of global water resources including virtual water trading has been made.
The three components of water availability considered for each grid were local runoff, routed flow from upstream and virtual
water trading. Several assumptions were postulated to convert country-base estimations of virtual water trading to grid values.
The results show that unequal spatial distribution of global water resources had been considerably neutralized by virtual
water trading. A large proportion of people in the Middle-East, North-Africa and Sub-Sahara region are able to relieve their
water stress through virtual water import. The paper also reports two hypothetical scenarios with extremes of natural flow
availability based on the presence and absence of routed upstream flow. 相似文献
114.
The MnCl2-UCl4 system was studied employing differential thermal analysis, common thermal analysis and high-temperature cryometry. From the results obtained, both the phase diagram and the thermodynamic characteristics of liquid phases of the system have been determined. The results were discussed in terms of regularities found in the phase equilibria of binary salt systems with common anion and compared with those for other systems of the type MCln-UCl4. It appeared that the results confirmed earlier predictions on the title system. 相似文献
115.
Marianna Gabriella Rispoli Silvia Valentinuzzi Giovanna De Luca Piero Del Boccio Luca Federici Maria Di Ioia Anna Digiovanni Eleonora Agata Grasso Valeria Pozzilli Alessandro Villani Antonio Maria Chiarelli Marco Onofrj Richard G. Wise Damiana Pieragostino Valentina Tomassini 《International journal of molecular sciences》2021,22(20)
Metabolomics-based technologies map in vivo biochemical changes that may be used as early indicators of pathological abnormalities prior to the development of clinical symptoms in neurological conditions. Metabolomics may also reveal biochemical pathways implicated in tissue dysfunction and damage and thus assist in the development of novel targeted therapeutics for neuroinflammation and neurodegeneration. Metabolomics holds promise as a non-invasive, high-throughput and cost-effective tool for early diagnosis, follow-up and monitoring of treatment response in multiple sclerosis (MS), in combination with clinical and imaging measures. In this review, we offer evidence in support of the potential of metabolomics as a biomarker and drug discovery tool in MS. We also use pathway analysis of metabolites that are described as potential biomarkers in the literature of MS biofluids to identify the most promising molecules and upstream regulators, and show novel, still unexplored metabolic pathways, whose investigation may open novel avenues of research. 相似文献
116.
Valeria Consoli Valeria Sorrenti Valeria Pittal Khaled Greish Agata Grazia DAmico Giuseppe Romeo Sebastiano Intagliata Loredana Salerno Luca Vanella 《International journal of molecular sciences》2022,23(10)
The term ferroptosis refers to a peculiar type of programmed cell death (PCD) mainly characterized by extensive iron-dependent lipid peroxidation. Recently, ferroptosis has been suggested as a potential new strategy for the treatment of several cancers, including breast cancer (BC). In particular, among the BC subtypes, triple negative breast cancer (TNBC) is considered the most aggressive, and conventional drugs fail to provide long-term efficacy. In this context, our study’s purpose was to investigate the mechanism of ferroptosis in breast cancer cell lines and reveal the significance of heme oxygenase (HO) modulation in the process, providing new biochemical approaches. HO’s effect on BC was evaluated by MTT tests, gene silencing, Western blot analysis, and measurement of reactive oxygen species (ROS), glutathione (GSH) and lipid hydroperoxide (LOOH) levels. In order to assess HO’s implication, different approaches were exploited, using two distinct HO-1 inducers (hemin and curcumin), a well-known HO inhibitor (SnMP) and a selective HO-2 inhibitor. The data obtained showed HO’s contribution to the onset of ferroptosis; in particular, HO-1 induction seemed to accelerate the process. Moreover, our results suggest a potential role of HO-2 in erastin-induced ferroptosis. In view of the above, HO modulation in ferroptosis can offer a novel approach for breast cancer treatment. 相似文献
117.
Agata Szymaszkiewicz Marcin Talar Jakub Wodarczyk Mikoaj
wierczyski Adrian Bartoszek Julia Krajewska Anna Mokrowiecka Ewa Maecka-Wojciesko Jakub Fichna Marta Zieliska 《International journal of molecular sciences》2022,23(7)
Nearly 20% of elderly patients suffer from constipation, but the age-related changes in the gastrointestinal (GI) tract remain insufficiently elucidated. In this study, the alterations within the endogenous opioid system (EOS) as a potential cause of constipation in the elderly were evaluated. The GI functions were assessed in vitro and in vivo and compared between 6-, 12- and 18-month old mice. Moreover, the effect of opioid receptor (MOP, DOP, KOP) agonists on the mouse GI tract functions and the EOS components expression in mouse tissues and colonic biopsies from patients with functional constipation were determined. In the oldest mice, the GI peristalsis was significantly impaired as compared to the younger groups. The tissue response to MOP and DOP, but not KOP, agonists weakened with age in vitro; for DOP, it was confirmed in vivo. In the mouse upper GI tract, Oprm1, Oprd1, Oprk1 expression decreased with age; in the colon, Oprm1 expression increased. There were no differences in the expression of these genes in the colonic biopsies from patients >50 years old as compared to the younger group. In conclusion, the age-related impairment of the GI peristalsis may result from reduced MOP and DOP response to the activation with opioid agonists or the alterations in the EOS expression. 相似文献
118.
Magdalena Wytrwal-Sarna Magorzata Sekua-Stryjewska Agata Pomorska Ewa Oco Katarzyna Gajos Michal Sarna Ewa Zuba-Surma Andrzej Bernasik Krzysztof Szczubiaka 《International journal of molecular sciences》2022,23(16)
Recombinant human bone morphogenetic protein-2 (rhBMP-2) plays a key role in the stem cell response, not only via its influence on osteogenesis, but also on cellular adhesion, migration, and proliferation. However, when applied clinically, its supra-physiological levels cause many adverse effects. Therefore, there is a need to concomitantly retain the biological activity of BMP-2 and reduce its doses. Currently, the most promising strategies involve site-specific and site-directed immobilization of rhBMP-2. This work investigated the covalent and electrostatic binding of rhBMP-2 to ultrathin-multilayers with chondroitin sulfate (CS) or diazoresin (DR) as the topmost layer. Angle-resolved X-ray photoelectron spectroscopy was used to study the exposed chemical groups. The rhBMP-2 binding efficiency and protein state were studied with time-of-flight secondary ion mass spectrometry. Quartz crystal microbalance, atomic force microscopy, and enzyme-linked immunosorbent assay were used to analyze protein–substrate interactions. The effect of the topmost layer was tested on initial cell adhesion and short-term osteogenesis marker expression. The results show the highest expression of selected osteomarkers in cells cultured on the DR-ended layer, while the cellular flattening was rather poor compared to the CS-ended system. rhBMP-2 adhesion was observed only on negatively charged layers. Cell flattening became more prominent in the presence of the protein, even though the osteogenic gene expression decreased. 相似文献
119.
120.
Agata Rogowska Magorzata Stpiczyska Cezary Pczkowski Anna Szakiel 《International journal of molecular sciences》2022,23(20)
The interplay between steroids and triterpenoids, compounds sharing the same biosynthetic pathway but exerting distinctive functions, is an important part of the defense strategy of plants, and includes metabolic modifications triggered by stress hormones such as jasmonic acid. Two experimental models, Calendula officinalis hairy root cultures and greenhouse cultivated plants (pot plants), were applied for the investigation of the effects of exogenously applied jasmonic acid on the biosynthesis and accumulation of steroids and triterpenoids, characterized by targeted GC-MS (gas chromatography-mass spectroscopy) metabolomic profiling. Jasmonic acid elicitation strongly increased triterpenoid saponin production in hairy root cultures (up to 86-fold) and their release to the medium (up to 533-fold), whereas the effect observed in pot plants was less remarkable (two-fold enhancement of saponin biosynthesis after a single foliar application). In both models, the increase of triterpenoid biosynthesis was coupled with hampering the biomass formation and modifying the sterol content, involving stigmasterol-to-sitosterol ratio, and the proportions between ester and glycoside conjugates. The study revealed that various organs in the same plant can react differently to jasmonic acid elicitation; hairy root cultures are a useful in vitro model to track metabolic changes, and enhanced glycosylation (of both triterpenoids and sterols) seems to be important strategy in plant defense response. 相似文献