The interaction between chitosan and the polar head of phosphatidylcholine (PC) is discussed for a composite nanovesicle obtained by incorporating chitosan in the organic phase before PC self-assembling. Nanovesicles free of chitosan are studied in parallel to allow the comparison concerning modifications produced on the composite system. Zeta Potential increases in the presence of chitosan and with the increase in its concentration proving the localization of the polymer over the external surface of the vesicle as one interaction site. A (31)P resonance around 0 ppm, characteristic of the system, is reduced with addition of chitosan at 25 degrees C, indicating motional freedom reduction of the polar head phosphate group. The same resonance signal remains almost constant after increasing the temperature to 60 degrees C, suggesting that chitosan shields the phospholipids polar heads as a consequence of the electrostatic interactions leading to an increase in the thermodynamic stability of the composite.
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http://dx.doi.org/10.1016/j.colsurfb.2009.08.048 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Oncode Institute, Hubrecht Institute-Royal Netherlands Academy of Arts and Science, Utrecht 3584 CT, The Netherlands.
Matrigel/BME, a basement membrane-like preparation, supports long-term growth of epithelial 3D organoids from adult stem cells [T. Sato , , 262-265 (2009); T. Sato , , 1762-1772 (2011)].
View Article and Find Full Text PDFGait Posture
December 2024
School of Health and Exercise Sciences, The University of British Columbia Okanagan, Kelowna, British Columbia, Canada. Electronic address:
Background: To maintain standing balance, vestibular cues are processed and integrated with other sensorimotor signals to produce appropriate motor adjustments. Whole-body vestibular-driven postural responses are context-dependent and transformed based upon head and foot posture. Previous reports indicate the importance of intrinsic foot muscles during standing, but it is unclear how vestibular-driven responses of these muscles are modulated by alterations in stability and head posture.
View Article and Find Full Text PDFLangmuir
January 2025
College of Mining Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China.
Flotation is an interfacial process involving gas, liquid, and solid phases, where polar ionic promoters significantly influence both gas-liquid and solid-liquid interfaces during low-rank coal (LRC) flotation. This study examines how the structures of hydrophilic groups in cation-anion mixed promoters affect the interfacial flotation performance of LRC pulp using flotation tests, surface tension tests, wetting heat tests, and molecular dynamics simulations. Results indicate that cation-anion mixed promoters enhance the LRC floatability to varying degrees.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of California, San Diego, Chemistry and Biochemistry, 9500 Gilman Drive, Urey Hall 4120, 92093, La Jolla, UNITED STATES OF AMERICA.
Membrane-forming phospholipids are generated in cells by enzymatic diacylation of non-amphiphilic polar head groups. Analogous non-enzymatic processes may have been relevant at the origin of life and could have practical utility in membrane synthesis. However, aqueous head group diacylation is challenging in the absence of enzymes.
View Article and Find Full Text PDFNeuroinformatics
January 2025
Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.
The position and orientation of transcranial magnetic stimulation (TMS) coil, which we collectively refer to as coil placement, significantly affect both the assessment and modulation of cortical excitability. TMS electric field (E-field) simulation can be used to identify optimal coil placement. However, the present E-field simulation required a laborious segmentation and meshing procedure to determine optimal coil placement.
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