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Not AvailableTransporters play key roles in regulating the movement of molecules into and out of cells. Uniporters, the simplest class of transporters, use facilitated diffusion to translocate molecules across membranes down their concentration gradient. This process can be affected by the presence of additional substrates in the intra- and extracellular environment, which can either increase the net transport rate of a molecule via trans acceleration or decrease it via competitive inhibition. In this study, we derived mathematical models to describe the net transport rate of uniporters in the presence of multiple extracellular substrates or inhibitors. Analyses of these models identified four possible states for the system when two substrates are present, with two states leading to trans acceleration and the other two states resulting in inhibition. Finally, we found that the relation between kinetic constants that controls the fraction of transporters in the inward-facing open state is responsible for these behaviors. Our theoretical results provide a mathematical framework for understanding the dynamic response of uniporters in the presence of multiple substrates and inhibitors, which could have implications for various processes, from nutrient utilization to metabolic engineering. 

This study presents a facile strategy for fabricating chitosan/polyurethane nanoparticle (PU NP) bioplastic films that simultaneously enhance both ductility and strength due to their unique elastic node-grid structure. 

Abstract BackgroundGraduate‐level education is gaining attention in engineering education scholarship. While “socialization” is a key term in doctoral literature, little is known about how socialization occurs over time. One common assumption asserts that socialization increases over time, encompassing factors such as belongingness, research ability, and advisor relationship as students acclimate to the norms and values of their advisors, departments, universities, and disciplines. We investigate engineering doctoral student socialization trends: students likely to complete their degrees and those who have questioned whether to persist in their programs. Understanding these trends is essential, as many students consider leaving their programs. Purpose/HypothesisThis paper aims to understand how socialization processes occur over several years in engineering students who questioned leaving their PhD programs. Design/MethodWe present longitudinal survey data collected from two cohorts (N_A = 113 andN_B = 355) of engineering doctoral students at R1 universities in the United States. Data were collected over 2 years through SMS surveys with participants receiving text messages three times per week. We analyzed data using descriptive and time series analysis methods. ResultsBoth cohorts showed lower levels of belongingness over time, reported declining advisor relationships, and experienced higher levels of stress. Students later in their programs also reported deteriorating overall social relationships. These findings contradict canonical socialization theory, which expects socialization to naturally improve over time. ConclusionWhile many assume socialization occurs passively and students acculturate into their department and research team over time, our results show students who question whether to persist are de‐socializing from graduate school. 

Zero-noise extrapolation (ZNE) is a widely used quantum error mitigation technique that artificially amplifies circuit noise and then extrapolates the results to the noise-free circuit. A common ZNE approach is Richardson extrapolation, which relies on polynomial interpolation. Despite its simplicity, efficient implementations of Richardson extrapolation face several challenges, including approximation errors from the non-polynomial behavior of noise channels, overfitting due to polynomial interpolation, and exponentially amplified measurement noise. This paper provides a comprehensive analysis of these challenges, presenting bias and variance bounds that quantify approximation errors. Additionally, for any precision $\epsilon$, our results offer an estimate of the necessary sample complexity. We further extend the analysis to polynomial least squares-based extrapolation, which mitigates measurement noise and avoids overfitting. Finally, we propose a strategy for simultaneously mitigating circuit and algorithmic errors in the Trotter-Suzuki algorithm by jointly scaling the time step size and the noise level. This strategy provides a practical tool to enhance the reliability of near-term quantum computations. We support our theoretical findings with numerical experiments. 

Abstract The strong very high frequency (VHF) radiation from compact intra‐cloud discharges (CIDs) is attributed to streamers. An analytical model, taking altitude and applied electric field as input, is developed for effective representation of current for a double‐headed exponentially growing streamer. The decay of streamer current is attributed to two‐ and three‐body attachment of electrons to molecular oxygen. The model predicts streamers of growing strength and spatial scales at altitudes where electron losses due to three‐body attachment are suppressed with reducing air pressure. We show that CIDs at higher altitudes develop during a longer period such that the spectral content of recorded sferics shifts toward lower frequencies. The model is used to interpret the recorded sferics of two CIDs originating from km altitude in terms of radio signals emanating from an ensemble of streamers. The driving thundercloud electric fields are found to be , where is conventional breakdown threshold field.