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121.
Liu J Rodriguez i Zubiri M Vigolo B Dossot M Humbert B Fort Y McRae E 《Journal of nanoscience and nanotechnology》2007,7(10):3519-3523
Single-wall carbon nanotubes (SWNTs) have been functionalized by a diazonium method through both a classical thermal reaction and a microwave-assisted reaction. The functionalized SWNTs have been characterized by nIR-Vis-UV absorption spectroscopy, Raman spectroscopy, and thermal gravimetric analysis. The results show that SWNTs are covalently functionalized through both reactions and that the microwave-assisted reaction is more rapid. Moreover, optimal choice of the reaction time can prevent the microwave irradiation from the adverse effect of subsequently removing the functional groups on the SWNT surface. 相似文献
122.
Latchman H.A. Salzmann Ch. Gillet D. Bouzekri H. 《Education, IEEE Transactions on》1999,42(4):247-254
The rapid growth of the Internet and the media-rich extensions of the World Wide Web allow new developments in the way instructors transfer knowledge to their students. There is no doubt that nothing will replace synchronous learning through face to face interaction but it is sometimes not feasible for students to attend conventional classes due to distance or time constraints. This paper presents a model for using information technology to enhance the learning experience for conventional on-campus students, as well as for those students whose circumstances require that they be asynchronous in time or space. The approach described emphasizes a solution which allows students to attend the class in real time via the Internet, or to access asynchronously digitally stored video material with hyperlinks to online training resources at any time. The proposed solution permits interaction in real-time and asynchronously among students and between students and instructor, which is a key for effective learning. In addition, the instructor maintains a significant level of spontaneity in using multimedia material prepared in advance or using conventional chalkboard or hand written materials via traditional overhead projection. The paper describes the technical issues involved and the chosen solutions to provide enhanced live and archived classes. This paper provides some comments on the evaluation of the learning experience using this method of delivery for on-campus and distance education students. Finally the authors share their vision on future trends to improve the proposed learning environment and the need for an optimal balance between expositive teaching and active learning for both synchronous and asynchronous activities 相似文献
123.
Rafael Ovalle Seung T. Lim Brigitte Holder Chong K. Jue Carol Wood Moore Peter N. Lipke 《Yeast (Chichester, England)》1998,14(13):1159-1166
The rate of formation of spheroplasts of yeast can be used as an assay to study the structural integrity of cell walls. Lysis can be measured spectrophotometrically in hypotonic solution in the presence of Zymolyase, a mixture of cell wall-digesting enzymes. The optical density of the cell suspension decreases as the cells lyse. We optimized this assay with respect to enzyme concentration, temperature, pH, and growth conditions for several strains of Saccharomyces cerevisiae. The level of variability (standard deviation) was 1–5% between trials where the replications were performed on the same culture using enzyme prepared from the same lot, and 5–15% for different cultures of the same strain. This assay can quantitate differences in cell wall structure (1) between exponentially growing and stationary phase cells, (2) among different S. cerevisiae strains, (3) between S. cerevisiae and Candida albicans, (4) between parental and mutated lines, and (5) between drug- or chemically-treated cells and controls. © 1998 John Wiley & Sons, Ltd. 相似文献
124.
Luke Mansard David Baux Christel Vach Catherine Blanchet Isabelle Meunier Marjolaine Willems Valrie Faugre Corinne Baudoin Melody Moclyn Julie Bianchi Helene Dollfus Brigitte Gilbert-Dussardier Delphine Dupin-Deguine Dominique Bonneau Isabelle Drumare Sylvie Odent Xavier Zanlonghi Mireille Claustres Michel Koenig Vasiliki Kalatzis Anne-Franoise Roux 《International journal of molecular sciences》2021,22(24)
Usher syndrome is an autosomal recessive disorder characterized by congenital hearing loss combined with retinitis pigmentosa, and in some cases, vestibular areflexia. Three clinical subtypes are distinguished, and MYO7A and USH2A represent the two major causal genes involved in Usher type I, the most severe form, and type II, the most frequent form, respectively. Massively parallel sequencing was performed on a cohort of patients in the context of a molecular diagnosis to confirm clinical suspicion of Usher syndrome. We report here 231 pathogenic MYO7A and USH2A genotypes identified in 73 Usher type I and 158 Usher type II patients. Furthermore, we present the ACMG classification of the variants, which comprise all types. Among them, 68 have not been previously reported in the literature, including 12 missense and 16 splice variants. We also report a new deep intronic variant in USH2A. Despite the important number of molecular studies published on these two genes, we show that during the course of routine genetic diagnosis, undescribed variants continue to be identified at a high rate. This is particularly pertinent in the current era, where therapeutic strategies based on DNA or RNA technologies are being developed. 相似文献
125.
Axel Nechwatal Monika Nicolai Klaus-Peter Mieck Brigitte Heublein Gudrun Kühne Dieter Klemm 《大分子材料与工程》1999,271(1):84-92
The high wet fibrillation tendency of Lyocell fibres forms the background to this investigation. The wet abrasion behaviour can be improved by crosslinking reactions. Substances containing sulfato ethyl sulfonyl groups but different bridging groups were synthesised and optimised regarding to their application. The wet fibrillation tendency can be reduced clearly with these selected substances. If the concentration of the crosslinking agent on the fibre is the basis of comparisons the different structures have a similar effect on the fibrillation tendency. So the swollen Lyocell fibre permits a crosslinking reaction with curing agents of different size. 相似文献
126.
Hellstern D Schulze K Schöpf B Petri-Fink A Steitz B Kamau S Hilbe M Koch-Schneidemann S Vaughan L Hottiger M Hofmann M Hofmann H von Rechenberg B 《Journal of nanoscience and nanotechnology》2006,6(9-10):3261-3268
PVA coated and fluorescent dye (Cy3.5) functionalized vinyl alcohol/vinyl amine copolymer coated superparamagnetic iron oxide nanoparticles (SPION) were evaluated for systemic distribution and elimination after intraarticular injection in sheep. Observation was done at 3, 24, 72, and 120 hours after injection using light microscopy, fluorescent microscopy, and confocal microscopy. No pathologic influence of SPION on the tissue harvested could be seen. A significantly increased iron content could be identified in the kidneys, lymph nodes, and spleen after injection of SPION. No particles were detected in the liver, the urinary, and the gall bladder. No positive fluorescent signal could be attributed to SPION throughout the organs. Our results indicated that the iron component of the SPION is possible to be incorporated into the physiologic iron metabolism after reabsorption in the proximal tubule system of the kidney and that concentration levels of Cy3.5 are too low to be detected throughout the body. 相似文献
127.
We present an in situ method for the selective manipulation of DNA-tagged nano-objects such as vesicles or gold colloids in aqueous solution, at neutral pH. The method makes use of the photosensitizer concept found in photodynamic therapy. Here, single-stranded DNA is immobilized onto a surface via the biotin/streptavidin linkage. If the streptavidin is fluorescently labeled, reactive species will be created during laser-induced photobleaching of the label. These reactive species can then completely or partly suppress the DNA hybridization and cause the removal of the streptavidin. The technique thereby enables a dynamic on–off control over surface density of immobilized DNA-tagged nano-objects. Furthermore, combining this in situ manipulation of DNA with prepatterning of single-stranded DNA in the micro and later in the nano range provides a means for the dynamic patterning required for applications in biosensing and nanotechnology. 相似文献
128.
An aerosol of green fluorescent protein-tagged Pseudomonas putida, created during high-pressure water cleaning of a coupon colonized by a biofilm of the green fluorescent protein bacterium, contaminated the water supply of an experimental setup. The upward spread of P. putida in a vertical pipe of supply water was 4.3 cm/day. Results highlight that a water supply to a food plant can be contaminated by an aerosol of environmental flora, created in typical cleaning operations, and become a reoccurring source of contamination. A practical response that could be taken in a food plant is briefly discussed. 相似文献
129.
130.
Leticia Hosta‐Rigau Olga Shimoni Brigitte Städler Frank Caruso 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(21):3573-3583
The design of compartmentalized carriers for advanced drug delivery systems or artificial cells and organelles is of interest for biomedical applications. Herein, a polymer carrier microreactor that contains two different classes of subcompartments, multilayered polymer capsules and liposomes, is presented. 50 nm‐diameter liposomes and 300 nm‐diameter polymer capsules are encapsulated into a larger polymer carrier capsule, demonstrating control over the spatial positioning of the subcompartments, which are either ‘membrane‐associated’ or 'free‐floating’ in the aqueous interior. Selective and spatially dependent degradation of the 300 nm‐diameter subcompartments (without destroying the structural integrity of the enzyme‐loaded liposomes) is also shown, by performing an encapsulated enzymatic reaction using the liposomal subcompartments. These findings cover several important aspects toward the development of engineered compartmentalized carrier vessels for the creation of artificial cell mimics or advanced therapeutic delivery systems. 相似文献