Journal of Biological Physics最新文献

Electroporation, a widely used physical method for transiently increasing cell permeability, facilitates molecular delivery for therapeutic and research applications. While electroporation proves to be a useful process, the mechanisms of pore formation and molecular transport remain incompletely understood. This study investigates the dynamics of electropore formation in lipid bilayers using molecular dynamics (MD) simulations and subsequent molecular transport by quantitative diffusion modeling. MD simulations reveal different stages of pore formation under applied electric fields, focusing on the lipid headgroup realignment and the hydration process of the pores. An FDM (Finite Difference Method)-based transport model quantifies the transport of molecules, such as glucose, calcein and bleomycin, using pore dimensions obtained from MD simulations. The results demonstrate a size-dependent transport efficiency, with smaller molecules diffusing more rapidly than larger ones. This work underscores the synergy between atomistic simulations and macroscopic transport modeling. Also, the findings offer valuable insights for optimizing electroporation protocols and developing targeted delivery systems for drugs and genetic material.

Ebola virus disease (EVD) is an acute life-threatening disease caused by highly pathogenic Ebolavirus (EBOV), with reported case fatality rates reaching 90%. There have been numerous EBOV outbreaks and epidemics since the first outbreak was reported in Africa in 1976. Despite the approval of three vaccines and two monoclonal antibody therapies by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of EVD the urgent need for alternative therapeutic strategies persists. In the present study, we screened a library of 235 phytocompounds derived from Azadirachta indica against the key EBOV viral protein 24 (VP24), VP30, VP35 and VP40 through a random forest-based machine learning model with an accuracy of 84.5%. Initially, 48 compounds were identified as active, and subsequent toxicity assessment refined the selection to a promising candidate, daucosterol. Molecular docking studies indicated that daucosterol exhibited significant binding affinity to all four viral proteins. Subsequent validation through molecular dynamics simulations confirmed the stability of daucosterol protein complexes. These results imply that daucosterol acts as a potential multitarget inhibitor against EBOV proteins and could serve as a promising lead compound for future therapeutic development against EVD.

Since Waddington proposed the concept of the “epigenetic landscape” in 1957, researchers have developed various methodologies to represent it in diverse processes. Studying the epigenetic landscape provides valuable qualitative information regarding cell development and the stability of phenotypic and morphogenetic patterns. Although Waddington’s original idea was a visual metaphor, a contemporary perspective relates it to the landscape formed by the basins of attraction of a dynamical system describing the temporal evolution of protein concentrations driven by a gene regulatory network. Transitions among these attractors can be driven by stochastic perturbations, with the cell state more likely to transition to the nearest attractor or to the one that presents the path of least resistance. In this study, we define the epigenetic landscape using the free energy potential obtained from the solution of the Fokker-Planck equation on the regulatory network. Specifically, we obtained a numerical approximate solution of the Fokker-Planck equation describing the Arabidopsis thaliana flower morphogenesis process. We observed good agreement between the coexpression matrix obtained from the Fokker-Planck equation and the experimental coexpression matrix. This paper proposes a method for obtaining this landscape by solving the Fokker-Planck equation (FPE) associated with a dynamical system describing the temporal evolution of protein concentrations involved in the process of interest. As these systems are high-dimensional and analytical solutions are often unfeasible, we propose a gamma mixture model to solve the FPE, transforming this problem into an optimization problem. This methodology can enhance the analysis of gene regulatory networks by directly relating theoretical mathematical models with experimental observations of coexpression matrices, thus providing a discriminating technique for competing models.

Eyring-Powell nanofluids have great potential for use in biomedical engineering to create more effective medical procedures and treatments due to their special properties of fluidity, efficient heat transfer, and interaction with biological systems. This study investigates bioconvection flow and its heat transfer characteristics of the magnetohydrodynamic ternary hybrid nanofluid containing silver, copper, and aluminum nanoparticles with human blood. The forced convection in a porous media, radiation, and viscous dissipation have been considered. The governing equations are reduced to dimensionless partial differential equations and further simplified using the local non-similarity method to obtain ordinary differential equations, which were solved numerically using the BVP4C algorithm. The results indicate that the concentration profiles reduce with inertia coefficients and Schmidt numbers, while radiation parameters increase the surface temperature. A higher Lewis number accelerates thermal diffusion, in contrast to mass diffusion. Fast dissipation of temperature prevents microbial growth and is useful in applications dealing with medicine administration and wound healing. These results support existing research and provide recommendations for further improvement of industrial and biological processes. As the (M) rises from (0.1) to (1,) the Nusselt number declines as follows: for (Ag) by around (4.48%-2.82%), for (Ag+Cu) by (13.57%, -7.58%) and for (Ag+Cu+Al) by (17.21%-12.53%). The Nusselt number increases around (1.01%-1.64%) as (lambda) rises from (0.1) to (0.3) for (Ag), for (Ag+Cu) by the Nusselt number increases by (6.77%-13.80%) and for (Ag+Cu+Al) by (13.84%-15.10%). The article proposes non-similar transformations for solving complex problems on the movement of ternary nanofluids. This provides insight into medical applications such as drug delivery and diagnostic tools and advances nanofluidic dynamics in healthcare.

Cytomegalovirus (CMV) is a significant clinical pathogen posing risks, especially for immunocompromised individuals. This study investigates the transport dynamics of CMV within viscoelastic saliva, focusing on factors influencing viral mobility. We employed mathematical models, including the Basset-Boussinesq-Oseen (BBO) equation, to analyze how viral density, particle diameter, saliva viscosity, and external electric and magnetic fields affect CMV movement in the oesophagus. Novel insights include the discovery that smaller CMV particles move significantly faster compared to larger ones, highlighting a critical aspect of viral infectivity. Additionally, we found that increased peristaltic wave amplitudes in the oesophagus greatly enhance viral velocity. More notably, our investigation reveals that the application of external magnetic fields can manipulate CMV transport by exerting forces that reduce viral mobility, thus potentially lowering infection rates through electromagnetic interactions. These findings underscore the complex interplay between fluid rheology, particle shape, and external fields in viral dynamics, suggesting novel therapeutic interventions aimed at controlling CMV spread based on saliva viscosity and electromagnetic manipulation. Our research paves the way for innovative strategies in viral infection management and therapeutic development.

Bone-substituted composite material based on bioceramics and polymer has enhanced their biological performance with dynamic properties such as bioactivity, biocompatibility, osseointegration, and mechanical stability, which can be used in a controlled drug delivery system for avoiding infections as well as pain. Here in this study, we developed a new approach for inducing antibacterial and osteogenic responses on biomaterial substrates via surface polarisation. The hydroxyapatite- sodium alginate composite was negatively polarised using a corona poling setup and characterised using X-ray diffraction analysis. The thermally stimulated depolarization current study showed a maximum current of 4.74 nA/cm², observed at a temperature of 480 °C. The wettability of the specimen was measured using contact angle measurements, which demonstrated that the polarised composite specimen exhibited higher water retention ability. The bacterial cell viability test was measured using the 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) assay, which revealed poor bacterial growth on polarised specimens as compared to their unpolarised counterparts. In addition, the osteogenic MG63 cell proliferation showed increased gene expression on polarised specimens. These findings showed that polarising hydroxyapatite- sodium alginate composite could be an excellent option to be used as an antibacterial bone filler matrix for faster healing as it showed both antibacterial and osteogenic activity.

The increasing prevalence of microplastics in water sources poses significant threats to both human health and environmental sustainability. Bisphenol A (BPA) and polyethylene terephthalate (PET), two hazardous microplastic contaminants, are known to cause endocrine disruption and other health risks. This study investigates the potential of graphene oxide (GO) as an efficient adsorbent for the removal of these contaminants through detailed molecular interaction analysis. The adsorption efficiencies of GO were quantitatively assessed, demonstrating strong binding affinities of ∆G = − 9.50 kcal/mol for BPA and ∆G = − 6.90 kcal/mol for PET. The adsorption process is primarily governed by π-π stacking interactions between the aromatic structure of the microplastics and the polycyclic surface of GO, with additional contributions from hydrogen bonding and van der Waals forces. Computational simulations revealed consistent binding across specific active sites on the GO surface, indicating minimal variation in adsorption performance. These findings highlight the potential of GO-based filtration systems for large-scale water treatment applications, offering a promising approach to mitigating microplastic contamination and ensuring safer water supplies. These findings highlight the potential of GO-based filtration systems for large-scale water treatment applications, offering a promising approach to mitigating microplastic contamination and ensuring safer water supplies. Future research should focus on optimizing GO-based filtration techniques and exploring their long-term environmental impact. 

The Epstein-Barr virus affects more than 90% of the world population and, consequently, is a virus whose infection dynamics should not be overlooked. It can cause the disease infectious mononucleosis and comes with other virus-associated diseases and conditions ranging from certain cancers to episodes of fatigue and depression. While previous epidemiological and virological modeling studies have worked out the details of possible infection dynamics scenarios, the current study takes a different approach. Using a nonlinear physics perspective and a fairly general epidemiological model, we identify the essential EBV infection dynamics along its so-called infection order parameter. We demonstrate that the essential dynamics describes the initial path that EBV infections take in the multi-dimensional model space. In particular, we show that the essential dynamics predicts the initial dynamics of the relevant subpopulations and describes how the subpopulations involved in an EBV infection outbreak organize themselves during the outbreak. Intervention and prevention measures are discussed in the context of the nonlinear physics perspective. An adverse synergy effect between two infection rate parameters is identified. An early warning system based on the so-called critical slowing down phenomenon is proposed for EBV infection waves in college and university student populations, which are populations particularly vulnerable to EBV infections.

Magnesium-based implants are highly valued in the biomedical field for biocompatibility and biodegradability, though their inherent low strength in body fluids is a limitation. This study addresses this by alloying magnesium with zinc and titanium to enhance its properties. Mechanical alloying was used to synthesize binary (Mg-Zn, Mg-Ti) and ternary (Mg-Zn-Ti) alloys, which were then compacted and sintered. The alloy powders, composed of 10 wt% Zn and 5 wt% Ti, were milled at 360 rpm for 10 h. Microstructural analysis revealed uniformly dispersed particles, with SEM confirming spherical and fine particles alongside laminates. XRD identified intermetallic compound formation. The ternary alloy demonstrated superior micro-hardness and Young’s modulus similar to human bone, making it particularly promising for biomedical applications. Incorporating zinc and titanium into the magnesium matrix resulted in a ternary alloy that outperformed its binary counterparts.