1,720,963 research outputs found
Monitoring Activity Of Living Cells Marked With Colloidal Semiconductor Quantum Dots
No full textFluorescent semiconductor nanocrystals in quantum confinement regime (quantum dots) present several well known features which make them very useful tools for biological labeling purposes. Low photo-bleaching rates, high chemical stability, active surface allowing conjugation to living cells, explains the success of this labeling procedure over the commonly used fluorescent dyes. In this paper we report the results obtained with high fluorescent core-shell CdTe-CdS (diameter = 3-7 nm) colloidal nanocrystals synthesized in aqueous medium and conjugated to glucose molecules, incubated with living yeast cells, in order to investigate their glucose up-take activity.6088Menezes, F.D., Brasil Jr., A.G., Moreira, W.L., Barbosa, L.C., Ferreira, R.C., Cerar, C.L., Farias, P.M.A., Santos, B.S., (2005) Microelectronics Journal, 36, pp. 989-991Alivisatos, A., (1996) J. Phys. Chem., 100, p. 13226Castro, V., Farias, P.M.A., Santos, B.S., Menezes, F.D., Ferreira, R., Fontes, A., Lima, P.R.M., Cesar, C.L., (2004) Blood, 104 (11), pp. 741aBrus, L.E., (1991) Appl. Phys. A, 53, p. 465Weller, H., (1993) Adv. Mater., 5 (2), p. 88Brus, L.E., Harkless, J.A.W., Stillinger, F.H., (1996) J. Am. Chem. Soc., 118, p. 4834Schaller, R.D., Klimov, V.I., (2004) Phys. Rev. Lett., 92, p. 186601Gao, M., Sun, J., Dulkeith, E., Gaponik, N., Lemmer, U., Feldmann, J., (2002) Langmuir, 18, p. 4098Pileni, M.P., (2000) Catal. Today, 58, p. 151Moreira, W.L., Fontes, A., Neves, A.A.R., Thomas, A.A., Barbosa, L.C., De Menezes, F.D., Farias, P.M.A., Cesar, C.L., (2005) Proc. Spie: Genet. Eng. Opt. Probes Biomed. Appl. III, 5704, p. 36Farias, P.M.A., Santos, B.S., Menezes, F.D., Cesar, C.L., Fontes, A., Barjas-Castro, M.L., Castro, V., Ferreira, R.C., (2005) Journal of Biomedical Optics, 10 (4), pp. 44023-44026Farias, P.M.A., Santos, B.S., Menezes, F.D., Cesar, C.L., Fontes, A., Barjas-Castro, M.L., Castro, V., Ferreira, R.C., (2005) Journal of Microscopy, 219 (3), pp. 103-108Borchert, H., Talapin, D.V., Gaponik, N., McGinley, C., Adam, S., Lobo, A., Möller, T., Weller, H., (2003) J. Phys. Chem. B, 107, p. 9662Rockenberger, J., Trögr, L., Rogach, A.L., Tischer, M., Grundmann, M., Eychmüller, A., Weller, H., (1998) J. Chem. Phys, 108, p. 780
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Quantum Dots As Fluorescent Bio-labels In Cancer Diagnostic
No full textIn this work we present and discuss some results concerning the application of colloidal semiconductor quantum dots for cancer diagnostic. We have prepared and applied different core-shell semiconductor quantum dots such as Cadmium Teluride-Cadmium Sulfide (CdTe-CdS) and Cadmium Sulfide - Cadmium Hydroxide (CdS/Cd(OH)2). For the purpose of diagnostic with living cells, the CdS/Cd(OH)2 presented best results, maintaining high levels of luminescence as well high stability in biological media. The quantum dots were obtained in aqueous medium, by reacting Cd2+ and S2- in the presence of sodium polyphosphate as the stabilizing agent. Subsequent surface passivation with Cd(OH)2 was carried out to improve luminescence. At a pH of 7.2 the quantum dots were functionalized with a 0.01% glutaraldehyde solution and then, incubated with living healthy and neoplastic cells (glial, glioblastoms and cervical) and tissues (breast) in culture medium. Tissue and cell staining were evaluated by the laser scanning confocal microscopy. Fluorescence Microscopy was used as a primary tool in order to explore the labeling of the samples. The procedure presented in this work, shown to be very efficient as a potential tool for fast and precise cancer diagnostic. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.31140014008Borchert, H., Talapin, D.V., McGinley, C., (2003) J. Chem. Phys, 271, pp. 1800-1807Alivisatos, A.P., (1996) Science, 271, pp. 933-937Nowak, C., Döllefeld, H., Eychmüller, A., (2001) J. Chem. Phys, 114, pp. 489-494Eychmüller, A., (1996) J. Phys. Chem. B, 59, pp. 13226-13239Bruchez Jr., M.P., Moronne, M., Gin, P., Weiss, S., Alivisatos, A.P., (1998) Science, 281, pp. 2013-2016Chan, W.C.W., Nie, S., (1998) Science, 281, pp. 2016-2018Ballou, B., Lagerholm, B.C., Ernst, L.A., Bruchez, M.P., Waggoner, A.S., (2004) Bioconjug. Chem, 15, pp. 79-86Gao, X., Nie, S., (2003) Trends Biotech, 21 (9), pp. 371-373Äkerman, M.E., Chan, W.C.W., Laakkonen, P., Bhatia, S.N., Ruoslahti, E., (2002) Appl. Biol. Sci, 99 (20), pp. 12617-12621W. C. W. Chan, D. J. Maxwell, X. Gao, R. E. Bailey, M. Han, and S. Nie, Curr. Op. Bioteh. 13(1), 40-46 (2002)Mattheakis, L.C., Dias, J.M., Choi, Y., Gong, J., Bruchez, M.P., Liu, J., Wang, E., (2004) Anal Biochem, 327, pp. 200-208Petrov, D.V., Santos, B.S., Pereira, G.A.L., Donegá, C.M., (2002) J. Phys. Chem. B, 106 (21), pp. 5325-5334Farias, P.M.A., Santos, B.S., Menezes, F.D., Ferreira, R.C., Barjas-Castro, M.L., Castro, V., Lima, P.R.M., Cesar, C.L., (2005) J. Microscopy, 219 (3), pp. 103-108Farias, P.M.A., Santos, B.S., Menezes, F.D., Ferreira, R.C., Barjas-Castro, M.L., Castro, V., Lima, P.R.M., Cesar, C.L., (2005) J. Biom. Opt, 10 (4), pp. 44023-4402
Application Of Colloidal Semiconductor Quantum Dots As Fluorescent Labels For Diagnosis Of Brain Glial Cancer
No full textIn this work we present the preparation, characterization and conjugation of colloidal core shell CdS-Cd(OH)2 quantum dots to health and cancer glial rats living cells in culture media. The particles were obtained via colloidal synthesis in aqueous medium, with final pH=7.3-7.4. Laser Scan Confocal Microscopy (LSCM) and Fluorescence Microscopy were used to evaluate fluorescence intensities and patterns of health and cancer (glioblastoma) glial cells labeled with the quantum dots in different time intervals. Health and cancer glial cells clearly differ in their fluorescence intensities and patterns. These different fluorescence intensities and patterns may be associated to differences concerning cellular membrane and metabolic features of health and cancer cells. The results obtained indicate the potential of the methodology for fast and precise cancer diagnostics.6096Borchert, H., Talapin, D.V., McGinley, C., (2003) J. Chem. Phys., 271, pp. 1800-1807Alivisatos, A.P., (1996) Science, 271, pp. 933-937Nowak, C., Döllefeld, H., Eychmüller, A., (2001) J. Chem. Phys., 114, pp. 489-494Eychmuller, A., (1996) J. Phys Chem. B., 59, pp. 13226-13239Bruchez Jr., M.P., Moronne, M., Gin, P., Weiss, S., Alivisatos, A.P., (1998) Science, 281, pp. 2013-2016Chan, W.C.W., Nie, S., (1998) Science, 281, pp. 2016-2018Ballou, B., Lagerholm, B.C., Ernst, L.A., Bruchez, M.P., Waggoner, A.S., (2004) Bioconjug. Chem., 15, pp. 79-86Gao, X., Nie, S., (2003) Trends Biotech., 21 (9), pp. 371-373Äkerman, M.E., Chan, W.C.W., Laakkonen, P., Bhatia, S.N., Ruoslahti, E., (2002) Appl. Biol. Sci., 99 (20), pp. 12617-12621Chan, W.C.W., Maxwell, D.J., Gao, X., Bailey, R.E., Han, M., Nie, S., (2002) Curr. Op. Bioteh., 13 (1), pp. 40-46Mattheakis, L.C., Dias, J.M., Choi, Y., Gong, J., Bruchez, M.P., Liu, J., Wang, E., (2004) Anal Biochem., 327, pp. 200-208Trentin, A.G., Alvarez-Silva, M., Moura-Neto, V., (2001) Am J Physiol Endocrinol Metab., 281, pp. E1088-E1094Sousa, V.O., Romão, L., Moura-Neto, V., Gomes, F.C.A., (2004) Eur. J. Neurosci., 19, pp. 1721-1734Petrov, D.V., Santos, B.S., Pereira, G.A.L., Donegá, C.M., (2002) J. Phys. Chem. B., 106 (21), pp. 5325-5334Farias, P.M.A., Santos, B.S., Menezes, F.D., Ferreira, R.C., Barjas-Castro, M.L., Castro, V., Lima, P.R.M., Cesar, C.L., (2005) J. Microscopy, 219 (3), pp. 103-108. , 2005Farias, P.M.A., Santos, B.S., Menezes, F.D., Ferreira, R.C., Barjas-Castro, M.L., Castro, V., Lima, P.R.M., Cesar, C.L., (2005) J. Biom. Opt., 10 (4), pp. 440231-44023
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