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991.
Maria C. Teixeira Nicole S. Lameirinhas Joo P. F. Carvalho Armando J. D. Silvestre Carla Vilela Carmen S. R. Freire 《International journal of molecular sciences》2022,23(12)
Three-dimensional (3D) bioprinting is an innovative technology in the biomedical field, allowing the fabrication of living constructs through an approach of layer-by-layer deposition of cell-laden inks, the so-called bioinks. An ideal bioink should possess proper mechanical, rheological, chemical, and biological characteristics to ensure high cell viability and the production of tissue constructs with dimensional stability and shape fidelity. Among the several types of bioinks, hydrogels are extremely appealing as they have many similarities with the extracellular matrix, providing a highly hydrated environment for cell proliferation and tunability in terms of mechanical and rheological properties. Hydrogels derived from natural polymers, and polysaccharides, in particular, are an excellent platform to mimic the extracellular matrix, given their low cytotoxicity, high hydrophilicity, and diversity of structures. In fact, polysaccharide-based hydrogels are trendy materials for 3D bioprinting since they are abundant and combine adequate physicochemical and biomimetic features for the development of novel bioinks. Thus, this review portrays the most relevant advances in polysaccharide-based hydrogel bioinks for 3D bioprinting, focusing on the last five years, with emphasis on their properties, advantages, and limitations, considering polysaccharide families classified according to their source, namely from seaweed, higher plants, microbial, and animal (particularly crustaceans) origin. 相似文献
992.
J. M. Martínez H. Amarís J. Sanz 《Electrical Engineering (Archiv fur Elektrotechnik)》2006,88(5):403-409
The use of conventional low voltage induction motors fed by pulse width modulated (PWM) inverters has begun to present important problems. These waveforms consist of steep-fronted pulses having very short rise times (about 100 ns in modern IGBT bridges) and high frequency repetition rates (up to 20 kHz) whose immediate consequences are additional electrical stresses in an induction motors insulation system. In this paper a frequency domain model for the analysis and characterization of the internal voltage distribution in random wound coils is presented. The model allows voltage prediction in time domain when an inverse fast Fourier transform (FFT) transformation is performed, and requires only a few frequency domain impedance measurements. This methodology will be useful for accurately predicting the voltage distribution in motor windings during the design stage, and reducing the risk of premature failure in motor insulation. Experimental and theoretical results are presented and compared and model effectiveness using different approximations is studied. 相似文献
993.
分析了FeSO4和H2O2的初始浓度及溶液pH值对UV/Fenton法降解四环素废水的影响.结果表明四环素的初始浓度为25,mg/L时,降解四环素的最佳工况:FeSO4的初始浓度为0.05mmol/L,H2O2的初始浓度为10,mmol/L,pH值为2.5,在反应时间为60,min时,对四环素的去除率可达93.14%.另外,对自然光、太阳光、紫外光三种不同光照条件进行了对比试验,得出紫外光辐照下的四环素去除率最高,太阳光次之,自然光最小. 相似文献
994.
995.
桥头堡建设助推云南高等职业教育发展 总被引:2,自引:0,他引:2
桥头堡建设是国家的重要战略,是提升云南整体实力的重大举措,是国家交给云南的重大任务和重要使命。桥头堡建设对培养技能型高职人才提出了新的更高要求,云南高等职业教育面临着历史机遇与重大挑战,结合云南桥头堡建设实际,探讨了发展云南高等职业教育的思路和举措:更新观念,树立国际化教育理念;加强改革与调整,构建云南特色的高职教育体系;对接企业,推进校企深度合作,实现云南高等职业教育的大发展。 相似文献
996.
997.
M Pinyol L Hernandez M Cazorla M Balbín P Jares PL Fernandez E Montserrat A Cardesa C Lopez-Otín E Campo 《Canadian Metallurgical Quarterly》1997,89(1):272-280
Mantle cell lymphoma (MCL) is molecularly characterized by bcl-1 rearrangement and cyclin D1 gene overexpression. Some aggressive variants of MCL have been described with blastic or large cell morphology, higher proliferative activity, and shorter survival. The cyclin-dependent kinase inhibitors (CDKIs) p21Waf1 and p16INK4a have been suggested as candidates for tumor-suppressor genes. To determine the role of p21Waf1 and p16INK4a gene alterations in MCLs, we examined the expression, deletions, and mutations of these genes in a series of 24 MCLs, 18 typical, and 6 aggressive variants. Loss of expression and/or deletions of p21Waf1 and p16INK4a genes were detected in 4 (67%) aggressive MCLs but in none of the typical variants. Two aggressive MCLs showed a loss of p16INK4a expression. These cases showed homozygous deletions of p16INK4a gene by Southern blot analysis. An additional aggressive MCL in which expression could not be examined showed a hemizygous 9p12 deletion. Loss of p21Waf1 expression at both protein and mRNA levels was detected in an additional aggressive MCL. No p21Waf1 gene deletions or mutations were found in this case. The p21Waf1 expression in MCLs was independent of p53 mutations. The two cases with p53 mutations showed p21Waf1 and p16INK4a expression whereas the 4 aggressive MCLs with p16INK4a and p21Waf1 gene alterations had a wild-type p53. p21Waf1 and p16INK4a were expressed at mRNA and protein levels in all typical MCLs examined. No gene deletions or point mutations were found in typical variants. Two typical MCLs showed an anomalous single-stranded conformation polymorphism corresponding to the known polymorphisms at codon 148 of p16INK4a gene and codon 31 of p21Waf1 gene. These findings indicate that p21Waf1 and p16INK4a alterations are rare in typical MCLs but the loss of p21Waf1 and p16INK4a expression, and deletions of p16INK4a gene are associated with aggressive variants of MCLs, and they occur in a subset of tumors with a wild-type p53 gene. 相似文献
998.
999.
Avcı D. Yetiş H. Karaboğa F. Akdoğan M. Belenli İ. 《Journal of Superconductivity and Novel Magnetism》2021,34(8):2121-2129
Journal of Superconductivity and Novel Magnetism - In this study, mechanical and electrical characterization measurements were performed on non-bent and gradually bent IMD MgB2/Fe superconducting... 相似文献
1000.