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Nucleic acid aptamers have attracted much interest in the bioanalytical field and have been employed to construct aptamer-based sensors (aptasensors) for the determination of multifarious disease biomarkers, attributing to their prominent advantages, such as good chemical and thermodynamic stability, ease of synthesis, utilization, and low cost. Along with acquisition of more and more effective aptamers, numerous aptasensors have been developed with many techniques, including UV-Vis (colorimetry), fluorescence, surface-enhanced Raman scattering, chemiluminescence/electrochemiluminescence, and electrochemical methods, and various types of biomarkers were detected, such as cardiac troponin I, carcinoembryonic antigen, and C-reactive protein, etc. Through overviewing these related typical works, this minireview aims to reveal effective approaches to high sensitivity, for example, DNA-based amplification and nanoprobe design, point out critical issues that impede the further practical use, and hopefully contribute to the development of aptasensors in the future., Author(s): Liu He [sup.1] [sup.2] , Yuchun Guo [sup.2] [sup.3] , Yunhui Li [sup.1] [sup.4] , Jianwei Zhu [sup.4] , Jiangtao Ren [sup.2] , Erkang Wang [sup.2] Author Affiliations: (1) [...]

Single‐atom catalysts (SACs) with edge‐located metal active sites exhibit superior oxygen reduction reaction (ORR) performance due to their narrower energy gap and higher electron density. However, controllably designing such active sites to fully reveal their advantages remains challenging. Herein, rich edge‐located Fe‐N4 active sites anchored in hierarchically porous carbon nanofibers (denoted as e1‐Fe‐N‐C) are fabricated via an in situ zinc‐assisted thermal etching strategy. The e1‐Fe‐N‐C catalyst demonstrates superior alkaline ORR activity compared to counterparts with fewer edge‐located Fe‐N4 sites and commercial Pt/C. Density functional theory calculations show that the accumulation of more negative charges near the Fe‐N and the formation of partially reduced Fe state in the edge‐located Fe‐N4 sites reduce the energy barrier for the ORR process. Additionally, the unique hierarchically porous structures with mesopores and macropores facilitate full utilization of the active sites and enhance long‐range mass transfer. The zinc–air battery (ZAB) assembled with e1‐Fe‐N‐C has a peak power density of 198.9 mW cm−2, superior to commercial Pt/C (152.3 mW cm−2). The present strategy by facile controlling the amount of the zinc acetate template systematically demonstrates the superiority of edge‐located Fe‐N4 sites, providing a new design avenue for rational defect engineering to achieve high‐performance ORR. [ABSTRACT FROM AUTHOR]

We study the stochastic dynamics of the externally regulating gene circuit as an example of an eve-skipped gene stripe in the development of Drosophila. Three gene regulation regimes are considered: an adiabatic phase when the switching rate of the gene from the OFF to ON state is faster than the rate of mRNA degradation; a nonadiabatic phase when the switching rate from the OFF to ON state is slower than that of the mRNA degradation; and a bursting phase when the gene switching is fast and transcription is very fast, while the ON state probability is very low. We found that the rate of thermodynamic cost quantified by the entropy production rate can suppress the fluctuations of the gene circuit. A higher (lower) rate of thermodynamic cost leads to reduced (increased) fluctuations in the number of gene products in the adiabatic (nonadiabatic) regime. We also found that higher thermodynamic cost is often required to sustain the emergence of more gene states and, therefore, more heterogeneity coming from genetic mutations or epigenetics. We also study the stability of the gene state using the mean first passage time from one state to another. We found the monotonic decrease in time, i.e., in the stability of the state, in the transition from the nonadiabatic to adiabatic regimes. Therefore, as the higher rate of thermodynamic cost suppresses the fluctuations, higher stability requires higher thermodynamics cost to maintain. [ABSTRACT FROM AUTHOR]

Elevated CO2 concentrations have been observed to accelerate flowering time in Arabidopsis through the action of a highly conserved regulatory network controlled by miR156 and miR172. However, the network's robustness to the impact of increasing CO2 concentrations on flowering time remains poorly understood. In this study, we investigate this question by conducting a comprehensive analysis of the global landscape of network dynamics, including quantifying the probabilities associated with juvenile and flowering states and assessing the speed of the transition between them. Our findings reveal that a CO2 concentration range of 400–800ppm only mildly advances flowering time, contrasting with the dramatic changes from 200 to 300ppm. Notably, the feedback regulation of miR156 by squamosal promoter binding protein-like proteins (SPLs) plays a substantial role in mitigating the effects of increasing CO2 on flowering time. Intriguingly, we consistently observe a correlation between delayed flowering time and increased variance in flowering time, and vice versa, suggesting that this might be an intrinsic adaptation mechanism embedded within the network. To gain a deeper understanding of this network's dynamics, we identified the sensitive features within the feedback loops of miR156 SPLs and miR172—APETALA2 family proteins (AP2s), with the latter proving to be the most sensitive. Strikingly, our study underscores the indispensability of all feedback regulations in maintaining both juvenile and adult states as well as the transition time between them. Together, our research provides the first physical basis in plant species, aiding in the elucidation of novel regulatory mechanisms and the robustness of the miRNAs-regulated network in response to increasing CO2, therefore influencing the control of flowering time. Moreover, this study provides a promising strategy for engineering plant flowering time to enhance their adaptation and resilience. Author summary: This study investigates the impact of elevated atmospheric CO2 levels on the flowering time of Arabidopsis plants based on the underlying genetic regulatory network. While genetic insights into this pathway have been gained, it remains unclear how resilient this network is to increased CO2 levels and what its adaptive mechanisms is. We conducted a dynamical modeling and associated analysis on the network, exploring how CO2 concentrations influence flowering time. We employed the landscape and flux theory to quantify the global landscape for network dynamics, estimate the likelihood of different reproductive states, and assess transition speeds between them. By introducing "mutations" into the system, we identified the basin locations and depths of the landscape as well as the key elements in network. The study uncovered that the miR156—SPLs feedback circuit is responsible for stabilizing the pathway and mitigating the effects of elevated CO2, while the miR172—AP2s feedback circuit is well-stabilized but highly sensitive. This feedback mechanism in plant species offers valuable insights into how plants adapt to environmental challenges. The current study provides a foundation of understanding how miRNA feedback circuits respond to increased CO2 levels, suggesting future strategies for genetically engineering plant flowering to enhance their resilience. [ABSTRACT FROM AUTHOR]