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排序方式: 共有304条查询结果,搜索用时 296 毫秒
281.
The currently used composites produced by classical sintering methods are characterised by numerous limitations due to the difficulties in combining different materials with extreme properties. One of the ways to overcome these limitations is in the use of modern sintering methods, including the high pressure-high temperature process. This study describes the composite materials based on 316L austenitic steel reinforced with titanium diboride and examines the effect of sintering conditions on the mechanical properties and microstructure of sintered composites. It has been found that the key parameter in the manufacture of composites with optimal properties is the sintering time and temperature, while martensitic transformation taking place in the composite matrix can be controlled by the properly selected pressure applied during the sintering process. 相似文献
282.
Iwona Bernacka‐Wojcik Miriam Huerta Klas Tybrandt Michal Karady Mohammad Yusuf Mulla David J. Poxson Erik O. Gabrielsson Karin Ljung Daniel T. Simon Magnus Berggren Eleni Stavrinidou 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(43)
Electronic control of biological processes with bioelectronic devices holds promise for sophisticated regulation of physiology, for gaining fundamental understanding of biological systems, providing new therapeutic solutions, and digitally mediating adaptations of organisms to external factors. The organic electronic ion pump (OEIP) provides a unique means for electronically‐controlled, flow‐free delivery of ions, and biomolecules at cellular scale. Here, a miniaturized OEIP device based on glass capillary fibers (c‐OEIP) is implanted in a biological organism. The capillary form factor at the sub‐100 µm scale of the device enables it to be implanted in soft tissue, while its hyperbranched polyelectrolyte channel and addressing protocol allows efficient delivery of a large aromatic molecule. In the first example of an implantable bioelectronic device in plants, the c‐OEIP readily penetrates the leaf of an intact tobacco plant with no significant wound response (evaluated up to 24 h) and effectively delivers the hormone abscisic acid (ABA) into the leaf apoplast. OEIP‐mediated delivery of ABA, the phytohormone that regulates plant's tolerance to stress, induces closure of stomata, the microscopic pores in leaf's epidermis that play a vital role in photosynthesis and transpiration. Efficient and localized ABA delivery reveals previously unreported kinetics of ABA‐induced signal propagation. 相似文献
283.
Hatice Gen Jonas Hazur Emine Karakaya Barbara Dietel Faina Bider Jürgen Groll Christoph Alexiou Aldo R. Boccaccini Rainer Detsch Iwona Cicha 《International journal of molecular sciences》2021,22(5)
A hydrogel system based on oxidized alginate covalently crosslinked with gelatin (ADA-GEL) has been utilized for different biofabrication approaches to design constructs, in which cell growth, proliferation and migration have been observed. However, cell–bioink interactions are not completely understood and the potential effects of free aldehyde groups on the living cells have not been investigated. In this study, alginate, ADA and ADA-GEL were characterized via FTIR and NMR, and their effect on cell viability was investigated. In the tested cell lines, there was a concentration-dependent effect of oxidation degree on cell viability, with the strongest cytotoxicity observed after 72 h of culture. Subsequently, primary human cells, namely fibroblasts and endothelial cells (ECs) were grown in ADA and ADA-GEL hydrogels to investigate the molecular effects of oxidized material. In ADA, an extremely strong ROS generation resulting in a rapid depletion of cellular thiols was observed in ECs, leading to rapid necrotic cell death. In contrast, less pronounced cytotoxic effects of ADA were noted on human fibroblasts. Human fibroblasts had higher cellular thiol content than primary ECs and entered apoptosis under strong oxidative stress. The presence of gelatin in the hydrogel improved the primary cell survival, likely by reducing the oxidative stress via binding to the CHO groups. Consequently, ADA-GEL was better tolerated than ADA alone. Fibroblasts were able to survive the oxidative stress in ADA-GEL and re-entered the proliferative phase. To the best of our knowledge, this is the first report that shows in detail the relationship between oxidative stress-induced intracellular processes and alginate di-aldehyde-based bioinks. 相似文献
284.
J. Ková? J. Škriniarová J. Jakabovi? R. Srnánek B. ?ciana Iwona Zborowska-Lindert 《Microelectronics Journal》2009,40(3):562-564
We have prepared, characterized and discussed the performance of AlGaAs/GaAs heterojunction bipolar phototransistor (HPT) including Zn delta-doped base. Due to the existence of δ-doped sheets located in the middle of undoped GaAs base the δ-doped HPT devices exhibit low dark current, nearly zero offset voltage, saturation voltage ∼0.4 V, and rise and fall times in ns range at wavelength of 850 nm up to 6 V of applied voltage. Due to avalanche multiplication behavior at the collector junction, an increased optical gain G>10 can be reached for applied voltages in the range of 6-12 V. For voltages higher than the device breakdown voltage (∼12 V) switching and negative differential resistance (NDR) effect is measurable in the inverted mode of operation. 相似文献
285.
Wiktoria Wrobel Emilia Pach Iwona Ben-Skowronek 《International journal of molecular sciences》2021,22(11)
Achondroplasia (ACH) is a disease caused by a missense mutation in the FGFR3 (fibroblast growth factor receptor 3) gene, which is the most common cause of short stature in humans. The treatment of ACH is necessary and urgent because untreated achondroplasia has many complications, both orthopedic and neurological, which ultimately lead to disability. This review presents the current and potential pharmacological treatments for achondroplasia, highlighting the advantages and disadvantages of all the drugs that have been demonstrated in human and animal studies in different stages of clinical trials. The article includes the potential impacts of drugs on achondroplasia symptoms other than short stature, including their effects on spinal canal stenosis, the narrowing of the foramen magnum and the proportionality of body structure. Addressing these effects could significantly improve the quality of life of patients, possibly reducing the frequency and necessity of hospitalization and painful surgical procedures, which are currently the only therapeutic options used. The criteria for a good drug for achondroplasia are best met by recombinant human growth hormone at present and will potentially be met by vosoritide in the future, while the rest of the drugs are in the early stages of clinical trials. 相似文献
286.
Weekday sunlight exposure,but not vitamin D intake,influences the association between vitamin D receptor genotype and circulating concentration 25‐hydroxyvitamin D in a pan‐European population: the Food4Me study
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Ulrich Hoeller Christina P. Lambrinou George Moschonis Anna L. Macready Rosalind Fallaize Manuela Baur Franz F Roos Igor Bendik Keith Grimaldi Santiago Navas‐Carretero Rodrigo San‐Cristobal Peter Weber Christian A. Drevon Yannis Manios Iwona Traczyk Eileen R. Gibney Julie A. Lovegrove Wim H. Saris Hannelore Daniel Mike Gibney J. Alfredo Martinez Lorraine Brennan Tom R. Hill John C. Mathers 《Molecular nutrition & food research》2017,61(2)
287.
Exploring the association of dairy product intake with the fatty acids C15:0 and C17:0 measured from dried blood spots in a multipopulation cohort: Findings from the Food4Me study
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Viviana Albani Carlos Celis‐Morales Cyril F. M. Marsaux Hannah Forster Clare B. O'Donovan Clara Woolhead Anna L. Macready Rosalind Fallaize Santiago Navas‐Carretero Rodrigo San‐Cristobal Silvia Kolossa Christina Mavrogianni Christina P. Lambrinou George Moschonis Magdalena Godlewska Agnieszka Surwio Thomas E. Gundersen Siv E. Kaland Yannis Manios Iwona Traczyk Christian A. Drevon Eileen R. Gibney Marianne C. Walsh J. Alfredo Martinez Wim H. M. Saris Hannelore Daniel Julie A. Lovegrove Michael J. Gibney Ashley J. Adamson John C. Mathers Lorraine Brennan 《Molecular nutrition & food research》2016,60(4):834-845
288.
Front cover: Exploring the association of dairy product intake with the fatty acids C15:0 and C17:0 measured from dried blood spots in a multipopulation cohort: Findings from the Food4Me study
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Viviana Albani Carlos Celis‐Morales Cyril F. M. Marsaux Hannah Forster Clare B. O'Donovan Clara Woolhead Anna L. Macready Rosalind Fallaize Santiago Navas‐Carretero Rodrigo San‐Cristobal Silvia Kolossa Christina Mavrogianni Christina P. Lambrinou George Moschonis Magdalena Godlewska Agnieszka Surwio Thomas E. Gundersen Siv E. Kaland Yannis Manios Iwona Traczyk Christian A. Drevon Eileen R. Gibney Marianne C. Walsh J. Alfredo Martinez Wim H. M. Saris Hannelore Daniel Julie A. Lovegrove Michael J. Gibney Ashley J. Adamson John C. Mathers Lorraine Brennan 《Molecular nutrition & food research》2016,60(4):NA-NA
289.
Julia Borzyszkowska-Bukowska Justyna Grska Pawe Szczeblewski Tomasz Laskowski Iwona Gabriel Jakub Jurasz Katarzyna Kozowska-Tylingo Piotr Szweda Sawomir Milewski 《International journal of molecular sciences》2021,22(18)
Three aromatic heptaene macrolide antifungal antibiotics, Candicidin D, Partricin A (Gedamycin) and Partricin B (Vacidin) were subjected to controlled cis-trans → all trans photochemical isomerization. The obtained all-trans isomers demonstrated substantially improved in vitro selective toxicity in the Candida albicans cells: human erythrocytes model. This effect was mainly due to the diminished hemotoxicity. The molecular modeling studies on interactions between original antibiotics and their photoisomers with ergosterol and cholesterol revealed some difference in free energy profiles of formation of binary antibiotic/sterol complexes in respective membrane environments. Moreover, different geometries of heptaene: sterol complexes and variations in polyene macrolide molecule alignment in cholesterol-and ergosterol-containing membranes were found. None of these effects are of the crucial importance for the observed improvement of selective toxicity of aromatic heptaene antifungals but each seems to provide a partial contribution. 相似文献
290.
Małgorzata Tańska Iwona Konopka Daniela Rotkiewicz 《Journal of the science of food and agriculture》2008,88(12):2186-2193
BACKGROUND: The size and strength of rapeseeds are factors likely to determine their suitability for storage and processing. The mechanical properties of whole seeds depend mainly on their coat composition. This study investigates variations in seed strength and colour between different‐sized rapeseeds. The paper also presents an explanation of the differences in seed mechanical properties through analyses of coat fibre composition. RESULTS: The strength properties of seeds were dependent on seed size and correlated with seed equivalent diameter. All measured strength indices showed that seeds of diameter above 2 mm were the most resistant. The mechanical properties of seeds were also correlated with the colour of seed surface, indicating that the most resistant seeds were those with values of H > 60°, S < 15% and I < 19% in the HSI colour space. The resistance of individual seeds was attributed to the surface density of soluble and insoluble dietary fibre, especially cellulose and lignin. CONCLUSION: The results suggest that the highest mechanical resistance shown by the largest and blackest rapeseeds can be associated with the high surface density of fibre components in the seed coat. Copyright © 2008 Society of Chemical Industry 相似文献