Electrical membrane potential equations for liquid ion exchange membranes, characterized by the presence of uncharged associated species and by exclusion of co-ions (no electrolyte uptake) have been derived. The irreversible thermodynamic theories already developed for solid membranes with fixed charged site density have been extended to include the different physicochemical aspects of the liquid membranes. To this purpose the dissipation function has been written with reference to the fluxes of all the species present in the membrane. It has been found that the mobile charged site, the counterions, and the uncharged associated species contribute to the electrical membrane potential through their phenomenological coefficients. The electrical membrane potential equations have been integrated in isothermal and nonisothermal conditions for monoionic and biionic systems. The theoretical predictions have been experimentally tested by studying the electrical potential of liquid membranes formed with solutions of tetraheptylammonium salts in omicron-dichlorobenzene.
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http://dx.doi.org/10.1016/S0006-3495(76)85722-0 | DOI Listing |
J Chem Inf Model
January 2025
Unit of Biophysics, Department of Biochemistry and Molecular Biology, Facultat de Medicina, Av. Can Domènech s/n, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Catalonia, Spain.
Cell-penetrating peptides (CPPs) can translocate into cells without inducing cytotoxicity. The internalization process implies several steps at different time scales ranging from microseconds to minutes. We combine adaptive Steered Molecular Dynamics (aSMD) with conventional Molecular Dynamics (cMD) to observe nonequilibrium and equilibrium states to study the early mechanisms of peptide-bilayer interaction leading to CPPs internalization.
View Article and Find Full Text PDFPLoS Genet
January 2025
Department of Molecular Biosciences, Program in Molecular, Cellular, and Developmental Biology, KU Center for Genomics, University of Kansas, Lawrence, Kansas, United States of America.
Recent studies in vertebrates and Caenorhabditis elegans have reshaped models of how the axon guidance cue UNC-6/Netrin functions in dorsal-ventral axon guidance, which was traditionally thought to form a ventral-to-dorsal concentration gradient that was actively sensed by growing axons. In the vertebrate spinal cord, floorplate Netrin1 was shown to be largely dispensable for ventral commissural growth. Rather, short range interactions with Netrin1 on the ventricular zone radial glial stem cells was shown to guide ventral commissural axon growth.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Neurology, the Second Affiliated Hospital, Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710000, China.
Neurotransmitters and neuromodulators can be released via either action potential (AP)-evoked transient or AP-independent continuous neurotransmission. The elevated AP-evoked neurotransmission in the primary sensory neurons plays crucial roles in hyperalgesia. However, whether and how the AP-independent continuous neurotransmission contributes to hyperalgesia remains largely unknown.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
January 2025
Research Institute of the, McGill University Health Centre, Montreal, QC, Canada.
The increasing shift from cannabis smoking to cannabis vaping is largely driven by the perception that vaping to form an aerosol represents a safer alternative to smoking and is a form of consumption appealing to youth. Herein, we compared the chemical composition and receptor-mediated activity of cannabis smoke extract (CaSE) to cannabis vaping extract (CaVE) along with the biological response in human bronchial epithelial cells. Chemical analysis using HPLC and GC/MS revealed that cannabis vaping aerosol contained fewer toxicants than smoke; CaSE and CaVE contained teratogens, carcinogens, and respiratory toxicants.
View Article and Find Full Text PDFAdv Healthc Mater
January 2025
School of Pharmacy, Queen's University Belfast, Lisburn Road 97, Belfast, BT9 7BL, UK.
Implantable drug delivery systems are crucial for achieving sustained delivery of active compounds to specific sites or systemic circulation. In this study, a novel reservoir-type implant combining a biodegradable rate-controlling membrane with a drug-containing core prepared using direct compression techniques is developed. The membrane is composed of poly(caprolactone) (PCL), and risperidone (RIS) served as the model drug.
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