Artículos de revistas: "Double-chain Amphiphiles"

1

Brun, Alice y Guita Etemad-Moghadam. "New Double-Chain and Aromatic (α-Hydroxyalkyl)phosphorus Amphiphiles". Synthesis, n.º 10 (2002): 1385–90. http://dx.doi.org/10.1055/s-2002-33111.

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2

Kimizuka, Nobuo, Takahiro Takasaki y Toyoki Kunitake. "Polymorphism in Bilayer Membranes of Novel Double-Chain Ammonium Amphiphiles". Chemistry Letters 17, n.º 11 (5 de noviembre de 1988): 1911–14. http://dx.doi.org/10.1246/cl.1988.1911.

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3

Koulov, Atanas V., Lauri Vares, Mahim Jain y Bradley D. Smith. "Cationic triple-chain amphiphiles facilitate vesicle fusion compared to double-chain or single-chain analogues". Biochimica et Biophysica Acta (BBA) - Biomembranes 1564, n.º 2 (agosto de 2002): 459–65. http://dx.doi.org/10.1016/s0005-2736(02)00496-0.

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4

Cescato, Claudio, Peter Walde y Pier Luigi Luisi. "Supramolecular Transformations of Vesicles from Amino Acid Based Double Chain Amphiphiles". Langmuir 13, n.º 16 (agosto de 1997): 4480–82. http://dx.doi.org/10.1021/la9701900.

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5

Feast, George C., Thomas Lepitre, Xavier Mulet, Charlotte E. Conn, Oliver E. Hutt, G. Paul Savage y Calum J. Drummond. "The search for new amphiphiles: synthesis of a modular, high-throughput library". Beilstein Journal of Organic Chemistry 10 (10 de julio de 2014): 1578–88. http://dx.doi.org/10.3762/bjoc.10.163.

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Amphiphilic compounds are used in a variety of applications due to their lyotropic liquid-crystalline phase formation, however only a limited number of compounds, in a potentially limitless field, are currently in use. A library of organic amphiphilic compounds was synthesised consisting of glucose, galactose, lactose, xylose and mannose head groups and double and triple-chain hydrophobic tails. A modular, high-throughput approach was developed, whereby head and tail components were conjugated using the copper-catalysed azide–alkyne cycloaddition (CuAAC) reaction. The tails were synthesised from two core alkyne-tethered intermediates, which were subsequently functionalised with hydrocarbon chains varying in length and degree of unsaturation and branching, while the five sugar head groups were selected with ranging substitution patterns and anomeric linkages. A library of 80 amphiphiles was subsequently produced, using a 24-vial array, with the majority formed in very good to excellent yields. A preliminary assessment of the liquid-crystalline phase behaviour is also presented.

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6

Azum, Naved, Malik Abdul Rub, Anish Khan, Maha M. Alotaibi, Abdullah M. Asiri y Mohammed M. Rahman. "Mixed Micellization, Thermodynamic and Adsorption Behavior of Tetracaine Hydrochloride in the Presence of Cationic Gemini/Conventional Surfactants". Gels 8, n.º 2 (17 de febrero de 2022): 128. http://dx.doi.org/10.3390/gels8020128.

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In this approach, tensiometry and UV-visible techniques are used to determine the effect of cationic gemini and conventional surfactants on tetracaine hydrochloride (TCH), an anesthetic drug. We have estimated micellar, interfacial, and energetic constraints. To gain a deep understanding of their mixed association behavior, the outputs were examined using different theoretical models. The critical micelle concentration for single and mixed amphiphiles was estimated. The cmc values of mixed amphiphiles were found between the individual amphiphiles due to strong attractive interaction (synergism) between the components after mixing. The non-ideal behavior of mixtures was confirmed by the larger values of ideal cmc than the experimental cmc values. The negative values of interaction parameter (β) and values of activity coefficients less than unity indicate strong synergistic interaction between drug and surfactant. The stability of the mixed systems is demonstrated by the negative Gibbs free energy of micellization and excess free energy of micellization. In contrast to a single chain surfactant, a double chain surfactant (gemini) exhibits better interactions with the drug. Spectral measurements (UV-visible spectra) were used to monitor the binding of the drug with surfactant (conventional as well as gemini). Studying these mixed aggregates could help to optimize their compositions and find synergistic properties between TCH monomers and surfactants.

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7

Kato, Shinji y Toyoki Kunitake. "Molecular Design of Black Lipid Membranes (BLM) by Polymerized Double-Chain Ammonium Amphiphiles". Chemistry Letters 20, n.º 2 (febrero de 1991): 261–64. http://dx.doi.org/10.1246/cl.1991.261.

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8

Nakashima, Naotoshi, Norihiro Yamada y Toyoki Kunitake. "A Fourier transform infrared study of bilayer membranes of double-chain ammonium amphiphiles". Journal of Physical Chemistry 90, n.º 15 (julio de 1986): 3374–77. http://dx.doi.org/10.1021/j100406a014.

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9

Sugimoto, Masakatsu, Kyoko Shibahara, Kenzi Kuroda, Toshikazu Hirao, Hideo Kurosawa y Isao Ikeda. "Bilayer Formation and Its Spectral Behavior of Double-Chain Amphiphiles Having Cinnamate Units". Langmuir 12, n.º 11 (enero de 1996): 2785–90. http://dx.doi.org/10.1021/la9509561.

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10

Masuyama, Araki, Tomoko Kawano, Yun-Peng Zhu, Toshiyuki Kida y Yohji Nakatsuji. "“Elasticity Index” for the Connecting Groups of Double-Chain Amphiphiles Bearing Two Hydrophilic Groups". Chemistry Letters 22, n.º 12 (diciembre de 1993): 2053–56. http://dx.doi.org/10.1246/cl.1993.2053.

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11

Kunitake, Toyoki, Naotoshi Nakashima y Masashi Kunitake. "Polymerization and membrane characteristics of aqueous bilayers of glutamate-based double-chain ammonium amphiphiles". Macromolecules 22, n.º 9 (septiembre de 1989): 3544–50. http://dx.doi.org/10.1021/ma00199a008.

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12

Leventis, Rania, Thomas Diacovo y John R. Silvius. "pH-dependent stability and fusion of liposomes combining protonatable double-chain amphiphiles with phosphatidylethanolamine". Biochemistry 26, n.º 12 (16 de junio de 1987): 3267–76. http://dx.doi.org/10.1021/bi00386a005.

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13

Sumida, Yasushi, Araki Masuyama, Toshihiro Oki, Toshiyuki Kida, Yohji Nakatsuji, Isao Ikeda y Masatomo Nojima. "Pressure−Area Isotherms for Double-Chain Amphiphiles Bearing Two Hydroxyl Groups Derived from Diepoxides". Langmuir 12, n.º 16 (enero de 1996): 3986–90. http://dx.doi.org/10.1021/la960268x.

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14

Zhou, Tianhua, Jianxi Zhao y Yi You. "Effect of the Interionic Distance on the Interfacial Behavior of Double-Chain Zwitterionic Amphiphiles". Journal of Dispersion Science and Technology 30, n.º 8 (13 de agosto de 2009): 1135–41. http://dx.doi.org/10.1080/01932690802701556.

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15

Silvius, John R. "Anomalous mixing of zwitterionic and anionic phospholipids with double-chain cationic amphiphiles in lipid bilayers". Biochimica et Biophysica Acta (BBA) - Biomembranes 1070, n.º 1 (noviembre de 1991): 51–59. http://dx.doi.org/10.1016/0005-2736(91)90145-x.

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16

Tojinbara, Toru, Masaaki Akamatsu, Kenichi Sakai y Hideki Sakai. "Oil-in-Water Emulsions Stabilized by Acylglutamic Acid–Alkylamine Complexes as Noncovalent-Type Double-Chain Amphiphiles". Langmuir 34, n.º 1 (20 de diciembre de 2017): 268–72. http://dx.doi.org/10.1021/acs.langmuir.7b03468.

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17

Clary, Laurence, Jacques Greiner, Catherine Santaella y Pierre Vierling. "synthesis of single- and double-chain fluorocarbon and hydrocarbon β-linked galactose amphiphiles derived from serine". Tetrahedron Letters 36, n.º 4 (enero de 1995): 539–42. http://dx.doi.org/10.1016/0040-4039(94)02335-9.

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18

Jung, Jong Hwa, Youngkyu Do, Young-A. Lee y Toshimi Shimizu. "Self-Assembling Structures of Long-Chain Sugar-Based Amphiphiles Influenced by the Introduction of Double Bonds". Chemistry - A European Journal 11, n.º 19 (19 de septiembre de 2005): 5538–44. http://dx.doi.org/10.1002/chem.200401288.

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19

Wakayama, Yutaka y Toyoki Kunitake. "Direct Observation of Ordered Bilayers in Cast Films of Double-Chain Ammonium Amphiphiles by Transmission Electron Microscopy". Chemistry Letters 22, n.º 8 (agosto de 1993): 1425–28. http://dx.doi.org/10.1246/cl.1993.1425.

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20

Faroux-Corlay, Barbara, Laurence Clary, Catherine Gadras, Djilali Hammache, Jacques Greiner, Catherine Santaella, Anne-Marie Aubertin, Pierre Vierling y Jacques Fantini. "Synthesis of single- and double-chain fluorocarbon and hydrocarbon galactosyl amphiphiles and their anti-HIV-1 activity". Carbohydrate Research 327, n.º 3 (julio de 2000): 223–60. http://dx.doi.org/10.1016/s0008-6215(00)00055-0.

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21

Nakashima, Naotoshi, Reiko Ando y Toyoki Kunitake. "Fluorescence Behavior and Energy Transfer of Cyanine Dyes Bound to Bilayer Membranes of Double-Chain Ammonium Amphiphiles". Bulletin of the Chemical Society of Japan 60, n.º 6 (junio de 1987): 1967–73. http://dx.doi.org/10.1246/bcsj.60.1967.

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22

Feast, George C., Thomas Lepitre, Nhiem Tran, Charlotte E. Conn, Oliver E. Hutt, Xavier Mulet, Calum J. Drummond y G. Paul Savage. "Inverse hexagonal and cubic micellar lyotropic liquid crystalline phase behaviour of novel double chain sugar-based amphiphiles". Colloids and Surfaces B: Biointerfaces 151 (marzo de 2017): 34–38. http://dx.doi.org/10.1016/j.colsurfb.2016.12.004.

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23

Jouani, M. A., S. Szönyi, H. Trabelsi, S. Y. Dieng, A. Cambon y H. J. Watzke. "Synthesis and aggregation properties of new fluorine-containing double-chain amphiphiles derived from di- and tri-substituted ureas". Supramolecular Science 2, n.º 2 (enero de 1995): 117–23. http://dx.doi.org/10.1016/0968-5677(96)89076-6.

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24

CLARY, L., J. GREINER, C. SANTAELLA y P. VIERLING. "ChemInform Abstract: Synthesis of Single- and Double-Chain Fluorocarbon and Hydrocarbon . beta.-Linked Galactose Amphiphiles Derived from Serine." ChemInform 26, n.º 22 (18 de agosto de 2010): no. http://dx.doi.org/10.1002/chin.199522269.

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25

Hong, Bing, Jonathan Lai, Loïc Leclercq, Marion Collinet-Fressancourt, Jean-Marie Aubry, Pierre Bauduin y Véronique Nardello-Rataj. "Binary and Ternary Phase Behaviors of Short Double-Chain Quaternary Ammonium Amphiphiles: Surface Tension, Polarized Optical Microscopy, and SAXS Investigations". Journal of Physical Chemistry B 117, n.º 47 (18 de noviembre de 2013): 14732–42. http://dx.doi.org/10.1021/jp406062b.

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26

Kato, Shinji y Toyoki Kunitake. "Aqueous Bilayers of Glutamate-Based Double-Chain Ammonium Amphiphiles II. Improvement of Polymerization and Membrane Characteristics by Ether-Linked Alkyl Tails". Polymer Journal 23, n.º 2 (febrero de 1991): 135–46. http://dx.doi.org/10.1295/polymj.23.135.

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27

Clary, Laurence, Catherine Gadras, Jacques Greiner, Jean-Paul Rolland, Catherine Santaella, Pierre Vierling y Annette Gulik. "Phase behavior of fluorocarbon and hydrocarbon double-chain hydroxylated and galactosylated amphiphiles and bolaamphiphiles. Long-term shelf-stability of their liposomes". Chemistry and Physics of Lipids 99, n.º 2 (junio de 1999): 125–37. http://dx.doi.org/10.1016/s0009-3084(99)00032-8.

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28

Ishikawa, Yuichi, Hiroaki Kuwahara y Toyoki Kunitake. "Self-assembly of bilayers from double-chain fluorocarbon amphiphiles in aprotic organic solvents: thermodynamic origin and generalization of the bilayer assembly". Journal of the American Chemical Society 116, n.º 13 (junio de 1994): 5579–91. http://dx.doi.org/10.1021/ja00092a008.

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29

Liang, Kang-Ning y Yong-Zheng Hui. "Investigation in monolayers of double-chain fluorocarbon amphiphiles Effect of headgroups on molecular packing and interaction between hydrocarbon and fluorocarbon monolayers". Chinese Journal of Chemistry 10, n.º 6 (27 de agosto de 2010): 481–86. http://dx.doi.org/10.1002/cjoc.19920100601.

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30

Pinazo, Aurora, Ramon Pons, Ana Marqués, Maribel Farfan, Anderson da Silva y Lourdes Perez. "Biocompatible Catanionic Vesicles from Arginine-Based Surfactants: A New Strategy to Tune the Antimicrobial Activity and Cytotoxicity of Vesicular Systems". Pharmaceutics 12, n.º 9 (9 de septiembre de 2020): 857. http://dx.doi.org/10.3390/pharmaceutics12090857.

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Their stability and low cost make catanionic vesicles suitable for application as drug delivery systems. In this work we prepared catanionic vesicles using biocompatible surfactants: two cationic arginine-based surfactants (the monocatenary Nα-lauroyl-arginine methyl ester—LAM and the gemini Nα,Nϖ-bis(Nα-lauroylarginine) α, ϖ-propylendiamide—C3(CA)2) and three anionic amphiphiles (the single chain sodium dodecanoate, sodium myristate, and the double chain 8-SH). The critical aggregation concentration, colloidal stability, size, and charge density of these systems were comprehensively studied for the first time. These catanionic vesicles, which form spontaneously after mixing two aqueous solutions of oppositely charged surfactants, exhibited a monodisperse population of medium-size aggregates and good stability. The antimicrobial and hemolytic activity of the vesicles can be modulated by changing the cationic/anionic surfactant ratio. Vesicles with a positive charge efficiently killed Gram-negative and Gram-positive bacteria as well as yeasts; the antibacterial activity declined with the decrease of the cationic charge density. The catanionic systems also effectively eradicated MRSA (Methicillin-resistant Staphylococcus Aureus) and Pseudomonas aeruginosa biofilms. Interestingly, the incorporation of cholesterol in the catanionic mixtures improved the stability of these colloidal systems and considerably reduced their cytotoxicity without affecting their antimicrobial activity. Additionally, these catanionic vesicles showed good DNA affinity. Their antimicrobial efficiency and low hemolytic activity render these catanionic vesicles very promising candidates for biomedical applications.

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31

Enjalbert, D., C. Bassilana y S. Szonyi. "Synthesis of new double-chain cationic and amphoteric F-alkylated amphiphiles derived from N-alkyl N-methyl N-[2-(F-alkyl)ethyl] amines". Tenside Surfactants Detergents 35, n.º 4 (1 de julio de 1998): 248–52. http://dx.doi.org/10.1515/tsd-1998-350404.

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32

Ariga, Katsuhiko y Yoshio Okahata. "Permeability controllable membranes. 11. Polymerized monolayers of single-, double-, and triple-chain silane amphiphiles and permeation control through the monolayer-immobilized porous glass plate in an aqueous solution". Journal of the American Chemical Society 111, n.º 15 (julio de 1989): 5618–22. http://dx.doi.org/10.1021/ja00197a018.

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33

Guo Bin, Luo, Liu Ting-Ting, Yu An-Chi, Zhao Xin-Sheng, Ying Li-Ming, Wu Deng-Guo y Huang Chun-Hui. "Self-Organiztion of a Double Chain Amphiphile DDPA Investigated by AFM". Acta Physico-Chimica Sinica 15, n.º 05 (1999): 385–89. http://dx.doi.org/10.3866/pku.whxb19990501.

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34

Luo, Guobin, Tingting Liu, Liming Ying, Xin Sheng Zhao, Yanyi Huang, Dengguo Wu y Chunhui Huang. "Aggregation and Self-Organization of a Chromophore-Labeled Double-Chain Amphiphile". Langmuir 16, n.º 8 (abril de 2000): 3651–59. http://dx.doi.org/10.1021/la991226m.

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35

MORISHIMA, Yotaro, Michiko SEKI, Shigeki NOMURA y Mikiharu KAMACHI. "Novel Coulombic Complexes of Amphiphilic Polyelectrolytes and Double-chain Surfactants." Proceedings of the Japan Academy. Ser. B: Physical and Biological Sciences 69, n.º 4 (1993): 83–88. http://dx.doi.org/10.2183/pjab.69.83.

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36

Pector, Véronique, Jacques Caspers, Sunanda Banerjee, Luc Deriemaeker, Robert Fuks, Abdel El Ouahabi, Michel Vandenbranden, Robert Finsy y Jean-Marie Ruysschaert. "Physico-chemical characterization of a double long-chain cationic amphiphile (Vectamidine) by microelectrophoresis". Biochimica et Biophysica Acta (BBA) - Biomembranes 1372, n.º 2 (julio de 1998): 339–46. http://dx.doi.org/10.1016/s0005-2736(98)00074-1.

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37

Shimomura, Masatsugu, Koichi Fujii, Peter Karg, Wolfgang Frey, Erich Sackmann, Paul Meller y Helmut Ringsdorf. "Homogeneous Langmuir-Blodgett Film of Double-Chain Ammonium Amphiphile Complexed with Anionic Polymer". Japanese Journal of Applied Physics 27, Part 2, No. 9 (20 de septiembre de 1988): L1761—L1763. http://dx.doi.org/10.1143/jjap.27.l1761.

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38

Uota, Masafumi, Mitsunori Yada, Masako Kuroki, Masato Machida y Tsuyoshi Kijima. "Carbons from furan-polymers prepared in the presence of a double-chain amphiphile". Carbon 42, n.º 11 (2004): 2207–13. http://dx.doi.org/10.1016/j.carbon.2004.04.033.

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39

Seki, Michiko, Yotaro Morishima y Mikiharu Kamachi. "Characterization of the complexes of amphiphilic polyanions and double-chain cationic surfactants". Macromolecules 25, n.º 24 (noviembre de 1992): 6540–46. http://dx.doi.org/10.1021/ma00050a024.

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40

Greiner, J., E. Myrtil, E. Dere, L. Zarif, J. G. Riess, B. Pucci y A. A. Pavia. "Double-chain amphiphilic telomers derived from tris-(hydroxymethyl)amidomethane for biomedical applications". Journal of Fluorine Chemistry 58, n.º 2-3 (agosto de 1992): 195. http://dx.doi.org/10.1016/s0022-1139(00)80645-4.

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41

Gonçalves, Rui A., Yeng-Ming Lam y Björn Lindman. "Double-Chain Cationic Surfactants: Swelling, Structure, Phase Transitions and Additive Effects". Molecules 26, n.º 13 (28 de junio de 2021): 3946. http://dx.doi.org/10.3390/molecules26133946.

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Double-chain amphiphilic compounds, including surfactants and lipids, have broad significance in applications like personal care and biology. A study on the phase structures and their transitions focusing on dioctadecyldimethylammonium chloride (DODAC), used inter alia in hair conditioners, is presented. The phase behaviour is dominated by two bilayer lamellar phases, Lβ and Lα, with “solid” and “melted” alkyl chains, respectively. In particular, the study is focused on the effect of additives of different polarity on the phase transitions and structures. The main techniques used for investigation were differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS and WAXS). From the WAXS reflections, the distance between the alkyl chains in the bilayers was obtained, and from SAXS, the thicknesses of the surfactant and water layers. The Lα phase was found to have a bilayer structure, generally found for most surfactants; a Lβ phase made up of bilayers with considerable chain tilting and interdigitation was also identified. Depending mainly on the polarity of the additives, their effects on the phase stabilities and structure vary. Compounds like urea have no significant effect, while fatty acids and fatty alcohols have significant effects, but which are quite different depending on the nonpolar part. In most cases, Lβ and Lα phases exist over wide composition ranges; certain additives induce transitions to other phases, which include cubic, reversed hexagonal liquid crystals and bicontinuous liquid phases. For a system containing additives, which induce a significant lowering of the Lβ–Lα transition, we identified the possibility of a triggered phase transition via dilution with water.

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42

Hägerstrand, Henry, Malgorzata Danieluk, Malgorzata Bobrowska-Hägerstrand, Veronique Pector, Jean-Marie Ruysschaert, Veronika Kralj-Iglič y Aleš Iglič. "Liposomes composed of a double-chain cationic amphiphile (Vectamidine) induce their own encapsulation into human erythrocytes". Biochimica et Biophysica Acta (BBA) - Biomembranes 1421, n.º 1 (septiembre de 1999): 125–30. http://dx.doi.org/10.1016/s0005-2736(99)00116-9.

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43

Abosheasha, Mohammed A., Toru Itagaki, Yoshihiro Ito y Motoki Ueda. "Tubular Assembly Formation Induced by Leucine Alignment along the Hydrophobic Helix of Amphiphilic Polypeptides". International Journal of Molecular Sciences 22, n.º 21 (8 de noviembre de 2021): 12075. http://dx.doi.org/10.3390/ijms222112075.

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The introduction of α-helical structure with a specific helix–helix interaction into an amphipathic molecule enables the determination of the molecular packing in the assembly and the morphological control of peptide assemblies. We previously reported that the amphiphilic polypeptide SL12 with a polysarcosine (PSar) hydrophilic chain and hydrophobic α-helix (l-Leu-Aib)6 involving the LxxxLxxxL sequence, which induces homo-dimerization due to the concave–convex interaction, formed a nanotube with a uniform 80 nm diameter. In this study, we investigated the importance of the LxxxLxxxL sequence for tube formation by comparing amphiphilic polypeptide SL4A4L4 with hydrophobic α-helix (l-Leu-Aib)2-(l-Ala-Aib)2-(l-Leu-Aib)2 and SL12. SL4A4L4 formed spherical vesicles and micelles. The effect of the LxxxLxxxL sequence elongation on tube formation was demonstrated by studying assemblies of PSar-b-(l-Ala-Aib)-(l-Leu-Aib)6-(l-Ala-Aib) (SA2L12A2) and PSar-b-(l-Leu-Aib)8 (SL16). SA2L12A2 formed nanotubes with a uniform 123 nm diameter, while SL16 assembled into vesicles. These results showed that LxxxLxxxL is a necessary and sufficient sequence for the self-assembly of nanotubes. Furthermore, we fabricated a double-layer nanotube by combining two kinds of nanotubes with 80 and 120 nm diameters—SL12 and SA2L12A2. When SA2L12A2 self-assembled in SL12 nanotube dispersion, SA2L12A2 initially formed a rolled sheet, the sheet then wrapped the SL12 nanotube, and a double-layer nanotube was obtained.

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44

Zhai, Jiali, Randy Suryadinata, Bao Luan, Nhiem Tran, Tracey M. Hinton, Julian Ratcliffe, Xiaojuan Hao y Calum J. Drummond. "Amphiphilic brush polymers produced using the RAFT polymerisation method stabilise and reduce the cell cytotoxicity of lipid lyotropic liquid crystalline nanoparticles". Faraday Discussions 191 (2016): 545–63. http://dx.doi.org/10.1039/c6fd00039h.

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Self-assembled lipid lyotropic liquid crystalline nanoparticles such as hexosomes and cubosomes contain internal anisotropic and isotropic nanostructures, respectively. Despite the remarkable potential of such nanoparticles in various biomedical applications, the stabilisers used in formulating the nanoparticles are often limited to commercially available polymers such as the Pluronic block copolymers. This study explored the potential of using Reversible Addition-Fragmentation chain Transfer (RAFT) technology to design amphiphilic brush-type polymers for the purpose of stabilising phytantriol and monoolein-based lipid dispersions. The synthesised brush-type polymers consisted of a hydrophobic C12 short chain and a hydrophilic poly(ethylene glycol)methyl ether acrylate (PEGA) long chain with multiple 9-unit poly(ethylene oxide) (PEO) brushes with various molecular weights. It was observed that increasing the PEO brush density and thus the length of the hydrophilic component improved the stabilisation effectiveness for phytantriol and monoolein-based cubosomes. Synchrotron small-angle X-ray scattering (SAXS) experiments confirmed that the RAFT polymer-stabilised cubosomes had an internal double-diamond cubic phase with tunable water channel sizes. These properties were dependent on the molecular weight of the polymers, which were considered in some cases to be anisotropically distributed within the cubosomes. The in vitro toxicity of the cubosomes was assessed by cell viability of two human adenocarcinoma cell lines and haemolytic activities to mouse erythrocytes. The results showed that phytantriol cubosomes stabilised by the RAFT polymers were less toxic compared to their Pluronic F127-stabilised analogues. This study provides valuable insight into designing non-linear amphiphilic polymers for the effective stabilisation and cellular toxicity improvement of self-assembled lipid lyotropic liquid crystalline nanoparticles.

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45

Higashi, Nobuyuki, Toyoki Kunitake y Tisato Kajiyama. "Efficient Oxygen Enrichment by a Langmuir-Blodgett Film of the Polyion Complex of a Double-Chain Fluorocarbon Amphiphile". Polymer Journal 19, n.º 2 (febrero de 1987): 289–91. http://dx.doi.org/10.1295/polymj.19.289.

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46

Lee, Jung y Chien-Hsiang Chang. "DNA association-enhanced physical stability of catanionic vesicles composed of ion pair amphiphile with double-chain cationic surfactant". Colloids and Surfaces B: Biointerfaces 121 (septiembre de 2014): 171–77. http://dx.doi.org/10.1016/j.colsurfb.2014.06.005.

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47

Hammerschick, Tim y Walter Vetter. "Profiling and Isolation of Ten Rare Branched-Chain Alkylresorcinols in Quinoa". Molecules 28, n.º 13 (5 de julio de 2023): 5220. http://dx.doi.org/10.3390/molecules28135220.

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Alkylresorcinols (∑ARs) are bioactive lipid compounds predominantly found in cereals. These amphiphilic compounds exist in a high structural diversity and can be divided into two main groups, i.e., 5-alkylresorcinols (ARs) and 2-methyl-5-alkylresorcinols (mARs). The pseudocereal quinoa has a very unique AR profile, consisting not only of straight-chain alkyl chains but also iso- and anteiso-branched isomers. Here, we describe a method for the isolation of such methyl-branched ARs and mARs from quinoa. The enrichment of the ∑AR fraction from the lipid extracts by centrifugal partition chromatography (CPC) was followed by ∑AR profiling using countercurrent chromatography (CCC) and GC/MS analysis of CCC fractions. A total of 112 ∑ARs could be detected, 63 of which had not been previously described in quinoa. Due to this high number of ∑ARs, the direct isolation of individual ARs was not possible using conventional CCC. Instead, the more powerful heart-cut mode was applied to enrich the target compounds. A final purification step—the separation of CCC-co-eluting mARs from ARs —was performed via silver ion chromatography. Altogether, ten rare branched-chain ∑ARs (five iso-branched mARs and five anteiso-branched ARs, including mAR19:0-i and AR20:0-a) were isolated with purities up to 98% in the double-digit mg range.

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Kocsisné Pfeifer, Éva, János Mink, István Gábor Gyurika y Judit Telegdi. "Effect of Heat Treatment on the Structure of Self-Assembled Undecenyl Phosphonic Acid Layers Developed on Different Stainless Steel Surfaces". Hungarian Journal of Industry and Chemistry 51, n.º 2 (8 de noviembre de 2023): 7–14. http://dx.doi.org/10.33927/hjic-2023-12.

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Deterioration caused by corrosion is well known, which can destroy metallic and non-metallic materials alike. Dissolved inhibitors of bionic micro- and nanocoatings can decrease the degree of undesirable corrosion in various ways. In this paper, a self-assembled molecular layer formed from undecenyl phosphonic acid developed on two different steel surfaces was the subject of our experiments. The influence of the metal composition, layer-forming conditions and post-heat treatment was documented by wettability measurements as well as surface roughness parameters; the change in surface morphology caused by the formation of a layer in addition to post-heat treatment was visualized by an atomic force microscope (AFM); and infrared spectroscopy elucidated the bindings of the amphiphilic molecules involved in the self-assembled layer to the metal surface as well as to each other. Over the course of the self-assembling process, the –P(O)(OH)2 head groups can fix the amphiphilic molecule to the solid surface through the metal oxide-hydroxide layer. The hydrophobic alkenyl chains remain together as a result of special forces, namely hydrogen bonds and van der Waals forces, between them. The double bond at the end of the alkenyl chain disturbs how well the layer is ordered. To improve the homogeneity of the molecular layer and increase its level of compactness, the self-assembled molecular (SAM) layer was heat treated to achieve a more compact molecular film that can perfectly cover the metal surface.

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49

Boettcher, Christoph. "Electron Microscopy of Selfassembling Lipids With Carbohydrate Headgroups and Their Stereochemical Interactions". Proceedings, annual meeting, Electron Microscopy Society of America 48, n.º 1 (12 de agosto de 1990): 498–99. http://dx.doi.org/10.1017/s0424820100181245.

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The spontaneous aggregation of amphiphilic molecules into ordered structures plays an important role in many biological and chemical systems. The stereochemistry of headgroups and their interaction in the mixed systems strongly influence the size and shape of the formed membranous aggregates .Upon cooling of the aqueous solution, containing D-Glu-8, micellar fibers of at least bimolecular diameter (4 nm) are formed and then converted within seconds into complex helical ropes of uniform screw sense. The preliminary structure, identified as a double stranded helix, could be detected by EM (a) after stabilisation in the presence of 2% phosphotungstic acid (Fig.1) and (b) using frozen hydrated specimens (Fig.2), which were prepared under controlled environment conditions at 60°C before plunging into liquid ethane. Small differences in the size and shape of the fibers, which were confirmed by image analysis, were traced back to adsorption effects on the carbon film and can be neglected, if frozen hydrated specimens are used.In an equimolar mixture of gluconamides, differentiated in the chain length, the formation of fibers is retarded and intermediate structures, such as micellar clusters are detectable (Fig.3). Racemic mixtures of hexonamides usually produce bilayer platelets (“Chiral Bilayer Effect”); if the enantiomers are again differentiated in the chain length, a spontaneous racemate resolution is observed (Fig.4, left-(M) and right-(P)handed helices!) and the formation of platelets (Fig.5) is retarded.

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50

Gessmann, Renate, Hans Brückner, Albrecht Berg y Kyriacos Petratos. "The crystal structure of the lipoaminopeptaibol helioferin, an antibiotic peptide fromMycogone rosea". Acta Crystallographica Section D Structural Biology 74, n.º 4 (1 de abril de 2018): 315–20. http://dx.doi.org/10.1107/s2059798318001857.

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The crystal structure of the natural nonapeptide antibiotic helioferin has been determined and refined to 0.9 Å resolution. Helioferin consists of helioferin A and B, which contain 2-(2′-aminopropyl)aminoethanol (Apae) and 2-[(2′-aminopropyl)methylamino]ethanol (Amae) at their respective alkanolamine termini. In addition, helioferin contains the unusual amino-acid residues α-aminoisobutyric acid (Aib) and (2S,4S,6S)-2-amino-6-hydroxy-4-methyl-8-oxodecanoic acid (Ahmod). The amino-terminus is capped with 2-methyl-n-1-octanoic acid (M8a). The peptide crystallizes with a 1:1 molar ratio of helioferin A and B in the monoclinic space groupC2, with unit-cell parametersa= 34.711,b= 10.886,c= 17.150 Å, β = 93.05°. The peptide backbone folds in a regular right-handed α-helical conformation, with eight intramolecular hydrogen bonds, all but one forming 5→1 interactions. The two aliphatic chains of the fatty-acyl (M8a) and the second residue (Ahmod) extend out of the α-helical structure in opposite directions and lead to a corkscrew-like shape of the peptide molecule. Halogen anions (Cl−and F−) have been co-crystallized with the peptide molecules, implying a positive charge at the aminoalcohol end of the peptide. In the tightly packed crystal the helices are linked head to tailviathe anions by electrostatic, hydrogen-bond and van der Waals interactions, forming continuous helical rods. Two nonparallel rods (forming an angle of 118°) interact directlyviahydrogen bonds andviathe anions, forming a double layer. Successive double layers are held together onlyviavan der Waals contacts. The helical axes of successive double layers are also related by an angle of 118°. The structure of helioferin reported here and the previously determined structure of the homologous leucinostatin A have a total straight length of about 21 Å, indicating a different membrane-modifying bioactivity from that of long-chain, amphiphilic peptaibols.

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