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| 2. |
- Khan, J, et al.
(författare)
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Classification and diagnostic prediction of cancers using gene expression profiling and artificial neural networks
- 2001
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 7:6, s. 673-679
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to develop a method of classifying cancers to specific diagnosticcategories based on their gene expression signatures using artificial neural networks (ANNs).We trained the ANNs using the small, round blue-cell tumors (SRBCTs) as a model. These cancersbelong to four distinct diagnostic categories and often present diagnostic dilemmas in clinicalpractice. The ANNs correctly classified all samples and identified the genes most relevant to theclassification. Expression of several of these genes has been reported in SRBCTs, but most havenot been associated with these cancers. To test the ability of the trained ANN models to recognizeSRBCTs, we analyzed additional blinded samples that were not previously used for the trainingprocedure, and correctly classified them in all cases. This study demonstrates the potentialapplications of these methods for tumor diagnosis and the identification of candidate targets fortherapy.
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| 3. |
- Caboi, F, et al.
(författare)
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Lipase action on a monoolein/sodium oleate aqueous cubic liquid crystalline phase - a NMR and X-ray diffraction study
- 2002
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Ingår i: Colloids and Surfaces B: Biointerfaces. - 1873-4367. ; 26:1-2, s. 159-171
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Tidskriftsartikel (refereegranskat)abstract
- The effect of adding Thermomyces (formerly Humicola) lanuginosa lipase (TLL) to a monoolein (MO)/sodium oleate (NaO) aqueous cubic liquid crystalline phase has been studied. H-1-NMR, C-13-NMR, H-1-PGSE (Pulsed-magnetic field Gradient Spin-Echo) self-diffusion measurements, and Small Angle X-ray Diffraction were used to follow the degradation of the cubic phase. The reaction sequence in terms of phase transitions follows the order bicontinuous cubic --> reverse hexagonal --> micellar cubic --> micellar phase and corresponds to the previously determined phase diagrams. These changes correlate with changes in the lipid composition observed by C-13-NMR and confirmed by HPLC analysis. The initial decrease of the diffusion coefficients of water and lipid can be related to the transformation of the bicontinuous cubic phase to a reverse hexagonal structure. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 4. |
- Marques, Eduardo F., et al.
(författare)
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Liquid Crystals and Phase Equilibria Binary Bile Salt-Water Systems
- 2000
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 16:11, s. 5178-5186
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Tidskriftsartikel (refereegranskat)abstract
- The phase behavior of several binary sodium bile salt-water systems is investigated over the entire concentration range, with emphasis on concentrated regions beyond the isotropic solution phase. The studied bile acid salts comprise the free salt sodium deoxycholate (SDC), the taurine conjugates sodium taurocholate (STC), sodium taurodeoxycholate (STDC), and sodium taurochenodeoxycholate (STCDC) and the glycine conjugate sodium glycodeoxycholate (SGDC). A combination of classical techniques is used, including phase diagram determination, polarizing microscopy, 2H NMR, and small-angle X-ray scattering (SAXS). The aggregation behavior in the isotropic micellar solutions of STC and STDC is also investigated by pulsed-field gradient NMR self-diffusion. The optical textures and the data from SAXS and 2H NMR clearly point to the formation of hexagonal liquid crystals, possibly of the reverse type, beyond the micellar solution for all the bile salts. Several unusual kinetic effects, such as very slow equilibration times and the formation of transient spherulitic crystals in biphasic regions, are observed. The phase diagrams and structural data are qualitatively discussed in terms of the molecular structure and solubility of the different salts. The formation of lyotropic liquid crystals by bile salts, which has remained unknown for decades, is clearly demonstrated in this work.
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| 5. |
- Marques, E F, et al.
(författare)
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Self-organization of double-chained and pseudodouble-chained surfactants: counterion and geometry effects
- 2003
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Ingår i: Advances in Colloid and Interface Science. - 1873-3727. ; 100-102, s. 83-104
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Tidskriftsartikel (refereegranskat)abstract
- Self-organization in aqueous systems based on ionic surfactants, and their mixtures, can be broadly understood by a balance between the packing properties of the surfactants and double-layer electrostatic interactions. While the equilibrium properties of micellar systems have been extensively studied and are understood, those of bilayer systems are less well characterized. Double-chained and pseudodouble-chained (or catanionic) surfactants are among the amphiphiles which typically form bilayer structures, such as lamellar liquid-crystalline phases and vesicles. In the past 10-15 years, an experimental effort has been made to get deeper insight into their aggregation patterns. With the double-chai ed amphiphiles, by changing counterion, adding salt or adding anionic surfactant, there are possibilities to depart from the bilayer aggregate in a controlled manner. This is demonstrated by several studies on the didodecyldimethylammonium bromide surfactant. Mixtures of cationic and anionic surfactants yield the catanionics, surfactants of the swelling type, and also show a rich phase behavior per se. A variety of liquid-crystalline phases and, in dilute regimes, equilibrium vesicles and different micellar shapes are often encountered. Phase diagrams and detailed structural studies, based on several techniques (NMR, microscopy and scattering methods), have been reported, as well as theoretical studies. The main features and conclusions emerging from such investigations are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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