ARTICLE | doi:10.20944/preprints202106.0475.v1
Subject: Life Sciences, Biochemistry Keywords: axon, neuron, electric circuit, capacitance , biophysics, HH model
Online: 18 June 2021 (11:08:11 CEST)
The most common and taught membrane theory assumes that the membrane behaves as a kind of electrical capacitance that is exposed to an electrical current generated by an ionic flow. If this statement is verifiable, it can be confirmed by the laws of physics, mathematics and in particular electricity. We will demonstrate that this hypothesis is not verified and that it is necessary to modify biophysics according to already established and experimentally verified principles of physics.
Subject: Life Sciences, Biophysics Keywords: axon; neuron; saltatory conduction; action potential; impulse propagation; HH model
Online: 30 August 2020 (18:39:44 CEST)
For more than 70 years, biologists and biophysicists have been trying to unravel the mystery that exists regarding the saltatory conduction of so-called myelinated neurons. Albert Einstein used the train metaphor to explain the theory of relativity. It is possible to use a similar metaphor to better understand this transient functioning of the neuron: the action potential. We will, once again, use a train to demonstrate unequivocally that the action potential does not jump from node of Ranvier to node of Ranvier (noR) as we thought it would. It is possible to describe that the neuron uses an elegant method to increase the speed of transmission of the neural message. It is also important to conclude that this increase in speed, contrary to the common idea, has a certain energy cost that is proportional to speed and in accordance with thermodynamics.
ARTICLE | doi:10.20944/preprints202204.0150.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: Ttc21a; Ttc21b; mouse knock-out; jaw; facial bone; viscerocranium; Hh signaling
Online: 16 April 2022 (03:36:54 CEST)
Ciliopathies are genetic syndromes that link skeletal dysplasias to dysfunction of primary cilia. Primary cilia are sensory organelles synthesized by intraflagellar transport (IFT) - A and B complexes, which traffic protein cargo along a microtubular core. We have reported that deletion of IFT-A gene, Thm2, together with a null allele of its paralog, Thm1, causes a small skeleton with small mandible or micrognathia in juvenile mice. Using micro-computed tomography, here we quantify the craniofacial defects of Thm2-/-;Thm1aln/- triple allele mutant mice. At postnatal day 14, triple allele mutant mice exhibit micrognathia, maxillary hypoplasia, and a decreased facial angle due to shortened maxilla, premaxilla, and nasal bones, reflecting altered development of facial anterior-posterior elements. In contrast, other ciliopathy-related craniofacial defects, such as cleft lip and/or palate, hypo-/hypertelorism, broad nasal bridge, craniosynostosis, and facial asymmetry, were not observed, suggesting development of the facial transverse dimension is intact. Calvarial-derived osteoblasts of triple allele mutant mice showed reduced bone formation in vitro that was ameliorated by Hedgehog agonist, SAG. Together, these data indicate that Thm2 and Thm1 genetically interact to regulate bone formation and sculpting of the postnatal face. The triple allele mutant mice present as a novel model to study craniofacial bone development.
ARTICLE | doi:10.20944/preprints202106.0356.v1
Subject: Life Sciences, Biochemistry Keywords: cell model; Bernstein; Nernst equation; membrane potential; GHK equation; HH model
Online: 14 June 2021 (11:50:34 CEST)
The cellular model we teach and have theorized assumes that the cell is the basic unit of multicellular living beings. This fundamental element has been the subject of many theories concerning its properties and the exchanges that exist with its environment. In this article, we demonstrate that certain functional aspects, in particular the electrical aspects related to diffusion, have not been correctly assumed or that certain initial conditions have been purely ignored and are in contradiction with physics, chemistry and thermodynamics.
Subject: Keywords: membrane potential, constant electric field , resting potential, action potentia, GHK eq., HH model
Online: 22 June 2021 (16:03:03 CEST)
An embryonic version of membrane theory can be date back to the Bernstein's work reported more than a hundred years ago. Such an originally old work has evolved conceptually and mathematically up until today, and it plays a central role in current membrane theory. Goldman-Hodgkin-Katz equation (GHK eq.) is one of the math-based monumental works, which constitutes the present membrane theory. Goldman theoretically derived GHK eq., but its physiological meaning was provided by the two renowned scientists, Hodgkin and Katz. These two employed an assumption that the electric field (EF) across the plasma membrane is constant to validate the GHK eq. physiologically. Proposal of Hodgkin-Huxley model (HH model) is another math-based monumental works developed from the membrane theory and now forms a fundamental part of the current membrane theory. GHK eq. and HH model are quite fundamental central concepts in the current physiology. Despite the broad acceptance of GHK eq. at present time, its prerequisite that the EF within the plasma membrane is constant is hardly believable. Especially when the action potential is generated, it sounds totally nonsense. Furthermore, the existence of constant EF within the plasma membrane is conceptually almost in conflict with the HH model. The authors will discuss those problematic issues the membrane theory inherits.
ARTICLE | doi:10.20944/preprints201804.0145.v1
Subject: Mathematics & Computer Science, Analysis Keywords: convex functions; AG, AH-convex functions; GA, GG, GH -convex functions and HA, HG, HH-convex function; integral inequalities
Online: 11 April 2018 (08:46:29 CEST)
In this paper we obtain some inequalities of Hermite-Hadamard type for composite convex functions. Applications for AG, AH-convex functions, GA, GG, GH-convex functions and HA, HG, HH-convex function are given. Applications for p, r-convex and LogExp functions are presented as well.
ARTICLE | doi:10.20944/preprints201806.0442.v1
Subject: Mathematics & Computer Science, Analysis Keywords: convex functions; AG, AH-h-convex functions; GA, GG, GH-h-convex functions and HA, HG, HH-h-convex function; integral inequalities
Online: 27 June 2018 (10:45:17 CEST)
In this paper we obtain some inequalities of Hermite-Hadamard type for composite convex functions. Applications for AG, AH-h-convex functions, GA, GG, GH-h-convex functions and HA, HG, HH-h-convex function are given.