Stochastic Dynamics of Electrical Membrane with Voltage-Dependent Ion Channel Fluctuations

Brownian ratchet like stochastic theory for the electrochemical membrane system of Hodgkin-Huxley (HH) is developed. The system is characterized by a continuous variable $Q_m(t)$, representing mobile membrane charge density, and a discrete variable $K_t$ representing ion channel conformational dynamics. A Nernst-Planck-Nyquist-Johnson type equilibrium is obtained when multiple conducting ions have a common reversal potential. Detailed balance yields a previously unknown relation between the channel switching rates and membrane capacitance, bypassing Eyring-type explicit treatment of gating charge kinetics. From a molecular structural standpoint, membrane charge $Q_m$ is a more natural dynamic variable than potential $V_m$; our formalism treats $Q_m$-dependent conformational transition rates $\lambda_{ij}$ as intrinsic parameters. Therefore in principle, $\lambda_{ij}$ vs. $V_m$ is experimental protocol dependent,e.g., different from voltage or charge clamping measurements. For constant membrane capacitance per unit area $C_m$ and neglecting membrane potential induced by gating charges, $V_m=Q_m/C_m$, and HH's formalism is recovered. The presence of two types of ions, with different channels and reversal potentials, gives rise to a nonequilibrium steady state with positive entropy production $e_p$. For rapidly fluctuating channels, an expression for $e_p$ is obtained.Comment: 8 pages, two figure

The Effect of Hypertriglyceridemia on the Development of Acute Pancreatitis and the Extent of Its Pathological Damage

This paper investigates the effect of hypertriglyceridemia on the development of acute pancreatitis and the extent of its pathological damage. It was found that hypertriglyceridemia has a significant correlation with the development of acute pancreatitis, and it may trigger acute pancreatitis by increasing blood viscosity and affecting microcirculation, leading to a decrease in pancreatic blood flow, which puts the pancreatic cells in a state of ischaemia and hypoxia. At the same time, hypertriglyceridemia can also affect the lipid metabolism and immune function of the pancreas, aggravating the progression of the disease and pathological damage. The influence of hypertriglyceridemia on the course of acute pancreatitis and the degree of pathological damage was confirmed through the analysis of specific clinical cases. On this basis, the possible mechanisms of hypertriglyceridemia on the degree of pathological damage in acute pancreatitis were explored, and possible mechanisms were proposed to affect the blood supply to the pancreas, to disrupt the balance of lipid metabolism in the pancreas, to affect the function of the immune system, and to directly affect the accumulation of pancreatic fluids and digestion

The Anthropocene Catastrophe: The Mystery of the Disappearance of Matacao in Through the Arc of the Rain Forest

The Japanese-American writer Karen Tei Yamashita’s first novel Through the Arc of the Rain Forest discloses the tremendous impact of technological activities on the natural environment in the Anthropocene. Centering on the mystery of the disappearance of Matacao in this novel, the present paper expounds that its disappearance is an environmental catastrophe of the Anthropocene resulting from the retaliation of nature for the replacement of it by human technological activities under the domination of the scientific and technological rationality. Yamashita’s presentation of the disappearance of Matacao serves as a warning to the world, aiming to advocate that the technological activities should not be controlled only by the scientific and technological rationality, but should recognize and respect the irreplaceability of nature, otherwise these activities will be retaliated by nature, triggering environmental disasters in the Anthropocene, bringing destruction to the Earth and the technological civilization.

Interacting heavy fermions in a disordered optical lattice

We have theoretically studied the effect of disorder on ultracold alkaline-earth atoms governed by the Kondo lattice model in an optical lattice via simplified double-well model and hybridization mean-field theory. Disorder-induced narrowing and even complete closure of hybridization gap have been predicted and the compressibility of the system has also been investigated for metallic and Kondo insulator phases in the presence of the disordered potential. To make connection to the experimental situation, we have numerically solved the disordered Kondo lattice model with an external harmonic trap and shown both the melting of Kondo insulator plateau and an compressibility anomaly at low-density

Cyclotron Dynamics of a Kondo Singlet in a Spin-Orbit-Coupled Alkaline-Earth Atomic Gas

We propose a scheme to investigate the interplay between Kondo-exchange interaction and quantum spin Hall effect with ultracold fermionic alkaline-earth atoms trapped in two-dimensional optical lattices using ultracold collision and laser-assisted tunneling. In the strong Kondo-coupling regime, though the loop trajectory of the mobile atom disappears, collective dynamics of an atom pair in two clock states can exhibit an unexpected spin-dependent cyclotron orbit in a plaquette, realizing the quantum spin Hall effect of the Kondo singlet. We demonstrate that the collective cyclotron dynamics of the spin-zero Kondo singlet is governed by an effective Harper-Hofstadter model in addition to second-order diagonal tunneling