The Rouse model with internal friction (RIF), a widely used theoretical framework to interpret the effects of internal friction on conformational transitions in biomolecules, is shown to be an approximate treatment that is based on preaveraging internal friction. By comparison with Brownian dynamics simulations of an exact coarse-grained model that incorporates fluctuations in internal friction, the accuracy of the preaveraged model predictions is examined both at and away from equilibrium. While the two models predict intrachain autocorrelations that approach each other for long enough chain segments, they differ in their predictions for shorter segments. Furthermore, the two models differ qualitatively in their predictions for the chain extension and viscosity in shear flow, which is taken to represent a prototypical out-of-equilibrium condition.We report an ion concentration polarization (CP) system that exceeds ohmic scaling, a barrier that has stood for more than four decades, by more than one order of magnitude. CP is used in many important applications, including the enrichment of trace analytes in microfluidic systems and water purification by electrodialysis. The mechanisms that control the current through these systems have been largely discovered, but the reduced currents and loss of efficiency imparted by the high resistance of the CP ion depleted zone have not been overcome. To obtain high currents, an ion permselective element with a microscale cross-section is interfaced with a macroscale reservoir. Confocal fluorescence microscopy and microparticle tracking velocimetry (μ-PTV) are used to characterize the depleted zone that emanates vertically from the CP inducing nanoporous gel into the macroscale reservoir. The shape and growth of the depleted zone and velocity in the surrounding bulk solution are consistent with natural convection being the driver of the depleted zone morphology and eliminating the high resistance created by the depleted zone in 1D and 2D systems. Once the resistance of the depleted zone is negated, the high currents are hypothesized to result from enhancement of counter-ion concentration in the nanoporous gel-filled microchannel. In contrast with conventional systems, the current increases monotonically and remains stable at a high quasi-steady level in the reported systems. These results may be used to increase the efficiency and performance of future devices that utilize CP, while the ability to collect purified water with this geometry is demonstrated.Classically, the configuration of electrodes (conductors) is used as a means to determine AC-electroosmotic flow patterns. In this paper, we use the configuration of insulator materials to achieve AC-electroosmotic flow patterning in a novel approach. We apply AC electric fields between parallel electrodes situated on the top and bottom of a microfluidic channel and separated by an insulating material. Channels of various cross-sectional shapes (e.g. rectangular and parallelogram) were fabricated by shaping the insulating material between the electrodes. We found that vortex flow patterns are induced depending on the cross-sectional shape of the channel. https://www.selleckchem.com/products/kc7f2.html A ****-shaped design with non-orthogonal corners gave rise to 2 vortices, whereas in a channel with a parallelogram shaped cross-section, only a single vortex was observed. The vortices were experimentally observed by analysing the 3D trajectories of fluorescent microparticles. From a theoretical analysis, we conclude that flow shaping is primarily caused by shaping the electrical field lines in the channel.The aim of the study was to evaluate the neuroprotective function of sea cucumber ovum peptide-derived NDEELNK and explore the underlying molecular mechanisms. NDEELNK exerted the neuroprotective effect by improving the acetylcholine (ACh) level and reducing the acetylcholinesterase (AChE) activity in PC12 cells. By molecular docking, we confirmed that the NDEELNK backbone and AChE interacted through hydrophobic and hydrogen bonds in contact with the amino acid residues of the cavity wall. NDEELNK increased superoxide dismutase (***) activity and decreased reactive oxygen species (ROS) production, thereby reducing mitochondrial dysfunction and enhancing energy metabolism. Our results demonstrated that NDEELNK supplementation alleviated scopolamine-induced PC12 cell damage by improving the cholinergic system, increasing energy metabolism and upregulating the expression of phosphorylated protein kinase A (p-PKA), brain-derived neurotrophic factor (BNDF) and nerve growth factor (NGF) signaling proteins in in vitro experiments. These results demonstrated that the sea cucumber ovum peptide-derived NDEELNK might play a protective role in PC12 cells.Rotation of a gear powered by active particles is numerically investigated in a circular chamber. Due to the nonequilibrium properties of active particles, net gear rotation is achieved in a bath composed of self-propelling particles. Our setup can convert the random motion of active particles into the directional rotation of the ratchet gear. The direction of rotation is determined by the asymmetry of the gear and the persistence length (the ratio of the self-propulsion speed to the rotation diffusion coefficient) of active particles. Remarkably, the direction of rotation for large persistence length is opposite to the direction of rotation for small persistence length. Therefore, for a given asymmetric gear, we can observe the rotation reversal when tuning the system parameters (e.g., the self-propulsion speed, the rotation diffusion coefficient, and the packing fraction of active particles). Our findings are relevant to the experimental pursuit of rectifying random motion to directional motion in active matter.Tumors are complex and highly variable, making it difficult for a single treatment strategy to be significantly effective for cancer therapy. Herein, we report a robust cascade biomimetic nanoplatform that integrates chemiluminescence-induced photodynamic therapy (CL-PDT), Fenton reaction-based chemodynamic therapy (CDT), and glucose oxidase (GOD)-mediated starvation therapy to synergistically enhance cancer treatment. For the nanoplatform of CPPO@porphyrin-MOF@Cancer cell membrane-GOD (C1@M@C2G), the ferric ion-linked porphyrin-MOF can trigger a Fenton reaction to reach CDT, the carried CPPO as an energy donor is used to excite a photo-sensitive porphyrin-MOF in situ to generate singlet oxygen (1O2) for PDT, GOD catalyzes glucose into H2O2 and gluconic acid to realize starvation therapy, and the cancer cell membrane wrapped onto the nanoparticle plays a key role in homologous targeting, which is conducive to achieving better therapeutic effects. Significantly, the porphyrin-MOF with catalase-like activity can generate O2 to effectively relieve tumor hypoxia, thereby enhancing the catalytic effect of GOD and the efficacy of PDT.
The Rouse model with internal friction (RIF), a widely used theoretical framework to interpret the effects of internal friction on conformational transitions in biomolecules, is shown to be an approximate treatment that is based on preaveraging internal friction. By comparison with Brownian dynamics simulations of an exact coarse-grained model that incorporates fluctuations in internal friction, the accuracy of the preaveraged model predictions is examined both at and away from equilibrium. While the two models predict intrachain autocorrelations that approach each other for long enough chain segments, they differ in their predictions for shorter segments. Furthermore, the two models differ qualitatively in their predictions for the chain extension and viscosity in shear flow, which is taken to represent a prototypical out-of-equilibrium condition.We report an ion concentration polarization (CP) system that exceeds ohmic scaling, a barrier that has stood for more than four decades, by more than one order of magnitude. CP is used in many important applications, including the enrichment of trace analytes in microfluidic systems and water purification by electrodialysis. The mechanisms that control the current through these systems have been largely discovered, but the reduced currents and loss of efficiency imparted by the high resistance of the CP ion depleted zone have not been overcome. To obtain high currents, an ion permselective element with a microscale cross-section is interfaced with a macroscale reservoir. Confocal fluorescence microscopy and microparticle tracking velocimetry (μ-PTV) are used to characterize the depleted zone that emanates vertically from the CP inducing nanoporous gel into the macroscale reservoir. The shape and growth of the depleted zone and velocity in the surrounding bulk solution are consistent with natural convection being the driver of the depleted zone morphology and eliminating the high resistance created by the depleted zone in 1D and 2D systems. Once the resistance of the depleted zone is negated, the high currents are hypothesized to result from enhancement of counter-ion concentration in the nanoporous gel-filled microchannel. In contrast with conventional systems, the current increases monotonically and remains stable at a high quasi-steady level in the reported systems. These results may be used to increase the efficiency and performance of future devices that utilize CP, while the ability to collect purified water with this geometry is demonstrated.Classically, the configuration of electrodes (conductors) is used as a means to determine AC-electroosmotic flow patterns. In this paper, we use the configuration of insulator materials to achieve AC-electroosmotic flow patterning in a novel approach. We apply AC electric fields between parallel electrodes situated on the top and bottom of a microfluidic channel and separated by an insulating material. Channels of various cross-sectional shapes (e.g. rectangular and parallelogram) were fabricated by shaping the insulating material between the electrodes. We found that vortex flow patterns are induced depending on the cross-sectional shape of the channel. https://www.selleckchem.com/products/kc7f2.html A bell-shaped design with non-orthogonal corners gave rise to 2 vortices, whereas in a channel with a parallelogram shaped cross-section, only a single vortex was observed. The vortices were experimentally observed by analysing the 3D trajectories of fluorescent microparticles. From a theoretical analysis, we conclude that flow shaping is primarily caused by shaping the electrical field lines in the channel.The aim of the study was to evaluate the neuroprotective function of sea cucumber ovum peptide-derived NDEELNK and explore the underlying molecular mechanisms. NDEELNK exerted the neuroprotective effect by improving the acetylcholine (ACh) level and reducing the acetylcholinesterase (AChE) activity in PC12 cells. By molecular docking, we confirmed that the NDEELNK backbone and AChE interacted through hydrophobic and hydrogen bonds in contact with the amino acid residues of the cavity wall. NDEELNK increased superoxide dismutase (SOD) activity and decreased reactive oxygen species (ROS) production, thereby reducing mitochondrial dysfunction and enhancing energy metabolism. Our results demonstrated that NDEELNK supplementation alleviated scopolamine-induced PC12 cell damage by improving the cholinergic system, increasing energy metabolism and upregulating the expression of phosphorylated protein kinase A (p-PKA), brain-derived neurotrophic factor (BNDF) and nerve growth factor (NGF) signaling proteins in in vitro experiments. These results demonstrated that the sea cucumber ovum peptide-derived NDEELNK might play a protective role in PC12 cells.Rotation of a gear powered by active particles is numerically investigated in a circular chamber. Due to the nonequilibrium properties of active particles, net gear rotation is achieved in a bath composed of self-propelling particles. Our setup can convert the random motion of active particles into the directional rotation of the ratchet gear. The direction of rotation is determined by the asymmetry of the gear and the persistence length (the ratio of the self-propulsion speed to the rotation diffusion coefficient) of active particles. Remarkably, the direction of rotation for large persistence length is opposite to the direction of rotation for small persistence length. Therefore, for a given asymmetric gear, we can observe the rotation reversal when tuning the system parameters (e.g., the self-propulsion speed, the rotation diffusion coefficient, and the packing fraction of active particles). Our findings are relevant to the experimental pursuit of rectifying random motion to directional motion in active matter.Tumors are complex and highly variable, making it difficult for a single treatment strategy to be significantly effective for cancer therapy. Herein, we report a robust cascade biomimetic nanoplatform that integrates chemiluminescence-induced photodynamic therapy (CL-PDT), Fenton reaction-based chemodynamic therapy (CDT), and glucose oxidase (GOD)-mediated starvation therapy to synergistically enhance cancer treatment. For the nanoplatform of CPPO@porphyrin-MOF@Cancer cell membrane-GOD (C1@M@C2G), the ferric ion-linked porphyrin-MOF can trigger a Fenton reaction to reach CDT, the carried CPPO as an energy donor is used to excite a photo-sensitive porphyrin-MOF in situ to generate singlet oxygen (1O2) for PDT, GOD catalyzes glucose into H2O2 and gluconic acid to realize starvation therapy, and the cancer cell membrane wrapped onto the nanoparticle plays a key role in homologous targeting, which is conducive to achieving better therapeutic effects. Significantly, the porphyrin-MOF with catalase-like activity can generate O2 to effectively relieve tumor hypoxia, thereby enhancing the catalytic effect of GOD and the efficacy of PDT.
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