1,721,278 research outputs found
Thermodynamics Of The Partitioning Of Poly(propylene Oxide) Between Aqueous And Chlorinated Organic Phases Compared To Poly(ethylene Oxide) And Other Hydrophilic Polymers
No full textThermodynamic functions associated with the partitioning of poly(propylene oxide), PPO, between aqueous and organic (chloroform, dichloromethane, and chlorobenzene) phases were determined and analyzed in comparison with those for the partitioning of poly(ethylene oxide), PEO, and poly (vinyl pyrrolidone), PVP. Amounts of water accompanying the partitioning of PPO to the organic phases were also measured. These results reveal that PPO partitioning is controlled by hydrophobic effects (entropie contribution), which was confirmed by the release of a significant amount of water molecules following the partitioning. Hydrophilic polymers like PVP and polyacrylamide, on the other hand, remain almost quantitatively in the aqueous phase. PEO remains a unique example of a polymer displaying high affinity for water, but that can be extracted to certain organic solvents (which should display hydrogen bond donating capacity). Copyright © 2006 John Wiley & Sons, Ltd.1911780785Harris, J.M., (1992) Poly(ethylene glycol) Chemistry - Biotechnical and Biomedical Applications, , Plenum Press: New YorkIsraelachivili, J., (1997) Proc. Natl. Acad. Sci, 94, p. 8378Almeida, M.L., Oliveira, C.L.P., Torriani, I.L., Loh, W., (2004) Colloids Surf. B, 38, p. 67Bailey Jr., F.E., Koleske, J.V., (1976) Poly(ethylene oxide), , Academic Press: New YorkSpitzer, M., Sabadini, E., Loh, W., (2002) J. Braz. Chem. Soc, 13, p. 7Spitzer, M., Sabadini, E., Loh, W., (2002) J. Phys. Chem. B, 106, p. 12448Paul, A., Griffiths, P.C., James, R., Willock, D.J., Rogueda, P.G., (2005) J. Pharm. Pharmacol, 57, p. 973Levy, G.B., Fergus, D., (1953) Anal. Chem, 9, p. 1408Beezer, A.E., Miles, R.J., Perry, B.F., (1987) Thermal and Energetic Studies of Cellular Biological Systems, p. 167. , James AM ed, Wright: LondonSee, for instance, Loh W, Beezer AE, Mitchell JC. Langmuir 199410: 343
MSI i LOH w rozwoju i prognozowaniu przebiegu nowotworów wywodzących się z komórki pęcherzykowej tarczycy
Full text linkMicrosatellite instability (MSI) and loss of heterozygosity (LOH) represent molecular disorders acquired by the cell during neoplastic
transformation. Both are associated with genetic instability. Functional silencing of tumour suppressor genes may be the consequence of
genomic instability, particularly of the globally occurring LOH phenomenon. Numerous studies have confirmed the role of MSI/LOH
at both the early and the late stages of thyroid tumourigenesis. This paper reviews the available study results on MSI/LOH significance
and prevalence in thyroid neoplasms. Additionally, it summarises the knowledge regarding the practical usage of the study findings on
MSI/LOH in aspects of cancer risk assessment as well as the development of prognostic markers for thyroid neoplasms.
(Pol J Endocrinol 2012; 63 (2): 126–136)Niestabilność mikrosatelitarna (MSI) i utrata heterozygotyczności (LOH) to zaburzenia molekularne, które w znacznym stopniu wiążą
się z nabywaniem przez komórkę nowotworową niestabilności genetycznej. Funkcjonalną konsekwencją niestabilności w genomie
— a w szczególności globalnie występującego LOH — może być utrata funkcji genów supresorowych. Przeprowadzone liczne badania
procesu nowotworzenia w gruczole tarczowym potwierdziły rolę MSI/LOH zarówno we wczesnych, jak i poźnych stadiach karcynogenezy.
W pracy przedstawiono wyniki badań dotyczących znaczenia i częstości występowania MSI/LOH w procesie nowotworzenia w gruczole
tarczowym. Artykuł jest także podsumowaniem stanu wiedzy na temat praktycznego wykorzystania rezultatów badań dotyczących
MSI/LOH w ocenie ryzyka wystąpienia nowotworu i w opracowaniu markerów prognostycznych przebiegu choroby nowotworowej
tarczycy. (Endokrynol Pol 2012; 63 (2): 126–136
Calorimetry Is Not Color-blind. Molecular Insights On Association Processes In Surfactant-polymer Mixtures Derived From Calorimetric Experiments
No full textThis comment will review and discuss recent results obtained with the use of calorimetry in assessing molecular information from complex phenomena such as association in surfactant/polymer mixtures. These examples were selected to support the view that it is possible to ally the great sensitivity of modern calorimeters with carefully planned experiments and, sometimes, ancillary techniques in order to derive detailed information on molecular interactions. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.541220242027Lamprecht, I., (1999) Handbook of Thermal Analysis and Calorimetry, p. 175. , R.B. Kemp (eds). Elsevier Science BV NetherlandsO'Brien, R., Haq, I., (2004) Biocalorimetry 2: Applications of Calorimetry in the Biological Science, p. 3. , J.E. Ladbury M.L. Doyle (eds). Wiley EnglandOlofsson, G., Wang, G., Interactions between surfactants and uncharged polymers in aqueous solution studied by microcalorimetry (1994) Pure Appl Chem, 66, pp. 527-532. , 10.1351/pac199466030527 1:CAS:528:DyaK2cXjt1Cluro%3DTam, K.C., Wyn-Jones, E., Insights on polymer surfactant complex structures during the binding of surfactants to polymers as measured by equilibrium and structural techniques (2006) Chemical Society Reviews, 35 (8), pp. 693-709. , DOI 10.1039/b415140mOlofsson, G., Loh, W., On the use of titration calorimetry to study the association of surfactants in aqueous solutions (2009) J Braz Chem Soc, 20, pp. 577-593. , 10.1590/S0103-50532009000400002 1:CAS:528:DC%2BD1MXms1Gksb0%3DKoper, G.J.M., Minkenberg, C.B., Upton, I.S., Van Esch, Sudhölter, E.J.R., Quantitatively interpreting thermal behavior of self-associating systems (2009) J Phys Chem B, 113, pp. 15597-15601. , 10.1021/jp909153n 1:CAS:528:DC%2BD1MXht1yntLfNDa Silva, R.C., Loh, W., Olofsson, G., Calorimetric investigation of the temperature effect on the interaction between poly(ethylene oxide) and sodium dodecylsulfate in water (2004) Thermochim Acta, 417, pp. 295-300. , 10.1016/j.tca.2003.07.025Loh, W., Teixeira, L.A.C., Lee, L.T., Isothermal calorimetric investigation of the interaction of poly(N-isopropylacrylamide) and ionic surfactants (2004) J Phys Chem B, 108, pp. 3196-3201. , 10.1021/jp037190v 1:CAS:528:DC%2BD2cXht1Wltb0%3DWang, G., Olofsson, G., Titration calorimetric study of the interaction between ionic surfactants and uncharged polymers in aqueous solution (1998) Journal of Physical Chemistry B, 102 (46), pp. 9276-9283Kujawa, P., Bangar Raju, B., Winnik, F.M., Interactions in water of alkyl and perfluoroalkyl surfactants with fluorocarbon- And hydrocarbon-modified poly(N-isopropylacrylamides) (2005) Langmuir, 21 (22), pp. 10046-10053. , DOI 10.1021/la051079uNiemiec, A., Loh, W., Interaction of ethylene oxide-propylene oxide copolymers with ionic surfactants studied by calorimetry: Random versus block copolymers (2008) Journal of Physical Chemistry B, 112 (3), pp. 727-733. , DOI 10.1021/jp0761362Dai, S., Tam, K.C., Isothermal titration calorimetric studies on the interaction between sodium dodecyl sulfate and polyethylene glycols of different molecular weights and chain architectures (2006) Colloids and Surfaces A: Physicochemical and Engineering Aspects, 289 (1-3), pp. 200-206. , DOI 10.1016/j.colsurfa.2006.04.035, PII S0927775706003347Lof, D., Niemiec, A., Schillen, K., Loh, W., Olofsson, G., A calorimetry and light scattering study of the formation and shape transition of mixed micelles of EO 20PO 68EO 20 triblock copolymer (P123) and nonionic surfactant (C 12EO 6) (2007) Journal of Physical Chemistry B, 111 (21), pp. 5911-5920. , DOI 10.1021/jp071101nWang, C., Tam, K.C., Interaction between polyelectrolyte and oppositely charged surfactant: Effect of charge density (2004) J Phys Chem B, 108, pp. 8976-8982. , 10.1021/jp049647m 1:CAS:528:DC%2BD2cXktlahs7g%3DWang, H., Wang, Y., Studies on interaction of poly(sodium acrylate) and poly(sodium styrenesulfonate) with cationic surfactants: Effects of polyelectrolyte molar mass, chain flexibility, and surfactant architecture (2010) J Phys Chem B, 114, pp. 10409-10416. , 10.1021/jp9102405 1:CAS:528:DC%2BC3cXptlymtLs%3DBrinatti, C., (2011), MSc Dissertation, Universidade Estadual de Campina
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
A Multimedia Information System Incorporating Hypermedia, Information Retrieval, and DBMS Technologies
No full textInvestigation Of Self-assembly And Micelle Polarity For A Wide Range Of Ethylene Oxide-propylene Oxide-ethylene Oxide Block Copolymers In Water
No full textCritical micelle concentrations (cmc) were determined for aqueous solutions of 15 EO-PO-EO (EO = ethylene oxide, PO = propylene oxide) block copolymers by using three different techniques: spectral changes of an iodine/iodide mixture, methyl yellow solubilization, and surface tension measurements. Two polymers showed no sign of micelle formation up to phase separation: one reverse (PO-EO-PO) and the other with low EO/PO ratio. The obtained cmc's were consistent for the different techniques employed and allowed the determination of the AG values associated with the micellization. These values were analyzed in terms of the EO and PO contributions, confirming the leading role of the hydrophobic PO units and revealing a small, but favorable, contribution of the hydrophilic EO chains, in contrast to the usual behavior of small nonionic surfactants. The polarity of the micelle solubilization sites was determined using the solvatochromic dye ET30, revealing environments similar to those observed for micelles of hydrocarbon surfactants. These findings, allied to the thermodynamic similarity between the micellization and the phase separation processes for the copolymers and PPO, support the view that the micellization is accompanied by a large dehydration of the PO units.144750756(1992) ICI Catalog, , ICI SurfactantsChu, B., (1995) Langmuir, 11, p. 414Alexandridis, P., Hatton, T.A., (1995) Colloids Surf., A, 96, p. 1Wanka, G., Hoffmann, H., Ulbricht, W., (1994) Macromolecules, 27, p. 4145Malmsten, M., Lindman, B., (1992) Macromolecules, 25, p. 5440Li, J.T., Cadwell, K.D., (1996) Colloids Surf., B, 7, p. 9Stolnik, S., Felumb, N.C., Heald, C.R., Garnett, M.C., Illum, L., Davis, S.S., (1997) Colloids Surf., A, 122, p. 151Svensson, M., Linse, P., Tjerneld, F., (1995) Macromolecules, 28, p. 3597Linse, P., (1993) J. Phys. Chem., 97, p. 13896Hurter, P.N., Scheutjens, J.M.H.M., (1993) Macromolecules, 26, p. 5030Holland, R.J., Parker, E.J., Zeld, F.R., (1995) J. Phys. Chem., 99, p. 11981Alexandridis, P., Athanassiou, V., Fukuda, S., Hatton, T.A., (1994) Langmuir, 10, p. 2604Alexandridis, P., Holzwarth, J.F., Hatton, T.A., (1994) Macromolecules, 27, p. 2414Mitchard, N.M., Beezer, A.E., Mitchell, J.C., Armstrong, J.K., Chowdhry, B.Z., Leharne, S., Buckton, G., (1992) J. Phys. Chem., 96, p. 9507Beezer, A.E., Loh, W., Mitchell, J.C., Royall, P.G., Smith, D.O., Tute, M.S., Armstrong, J.K., Crowther, N.J., (1994) Langmuir, 10, p. 4001Armstrong, J., Chowdhry, B., Brien, R., Beezer, A., Mitchell, J.C., Leharne, S., (1995) J. Phys. Chem., 99, p. 4590Paterson, I., Armstrong, J., Chowdhry, B., Leharne, S., (1997) Langmuir, 13, p. 2219Fleischer, G., (1993) J. Phys. Chem., 97, p. 517Wu, C., Liu, T., Chu, B., Schneider, D., Graziano, V., (1997) Macromolecules, 30, p. 4574Nivaggioli, T., Alexandridis, P., Hatton, T.A., Yekta, A., Winnik, M.A., (1995) Langmuir, 11, p. 730Irwin, J., Beezer, A.E., Mitchell, J.C., Buckton, G., Chowdhry, B.Z., Eagland, D., Crowther, N.J., (1993) J. Phys. Chem., 97, p. 2034Miano, F., Bailey, A., Luckham, Tadros, Th.F., (1992) Colloids Surf., 68, p. 9Gaisford, S., Beezer, A.E., Mitchell, J.C., Loh, W., Finnie, J.K., Williams, S.J., (1995) J. Chem. Soc., Chem. Commun., p. 1843Gaisford, S., Beezer, A.E., Mitchell, J.C., (1997) Langmuir, 13, p. 2606Galembeck, E., (1995), M.Sc. Dissertation, Universidade Estadual de Campinas, Campinas, BrazilLopes, J.R., Loh, W., Unpublished resultsVenkatesan, P., Cheng, Y., Kahne, D., (1994) J. Am. Chem. Soc., 116, p. 6955Atwood, D., Forence, A.T., (1983) Surfactants Systems Their Chemistry, Pharmacy and Biology, , Chapman and Hall: London, Chapter 3Alexandridis, P., Holzwarth, J.F., Hatton, T.A., (1995) J. Am. Oil Chem. Soc., 72, p. 823Mortensen, K., Brown, W., Jorgensen, E., (1994) Macromolecules, 27, p. 5654Alexandridis, P., Zhou, D., Khan, A., (1996) Langmuir, 12, p. 2690Mortensen, K., Pedersen, J.S., (1993) Macromolecules, 26, p. 805Yu, G.-E., Deng, Y., Dalton, S., Wang, Q.-G., Attwood, D., Price, C., Booth, C., (1992) J. Chem. Soc., Faraday Trans., 88, p. 2537Loh, W., Beezer, A.E., Mitchell, J.C., (1994) Langmuir, 10, p. 3431Reichardt, C., (1992) Chem. Soc. Rev., p. 147Drummond, C.J., Grieser, F., Healy, T., (1986) Faraday Discuss. Chem. Soc., 81, p. 9
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