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A quartz tuning fork and its qPlus configuration show different characteristics in their dynamic features, including peak amplitude, resonance frequency, and quality factor. Here, we present an electromechanical model that comprehensively describes the dynamic responses of an electrically driven tuning fork and its qPlus configuration. Based on the model, we theoretically derive and experimentally validate how the peak amplitude, resonance frequency, quality factor, and normalized capacitance are changed when transforming a tuning fork to its qPlus configuration. Furthermore, we introduce two experimentally measurable parameters that are intrinsic for a given tuning fork and not changed by the qPlus configuration. The present model and analysis allow quantitative prediction of the dynamic characteristics in tuning fork and qPlus, and thus could be useful to optimize the sensors' performance.
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http://dx.doi.org/10.3390/s19122686 | DOI Listing |
ACS Sens
August 2025
The McComish Department of Electrical Engineering and Computer Science, Jerome J. Lohr College of Engineering, South Dakota State University, Brookings, South Dakota 57007, United States.
Plants emit volatile organic compounds (VOCs) in response to biotic and abiotic stress, serving as early indicators of health. Among them, ()-2-Hexenal─a key green leaf volatile (GLV)─signals stress from pathogen infection or herbivory. Real-time detection of ()-2-hexenal at trace levels is crucial for early diagnosis, crop protection, and environmental sustainability.
View Article and Find Full Text PDFFEMS Microbiol Rev
August 2025
Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin St, 28049 Madrid, Spain.
Escherichia coli and Bacillus subtilis provide well-studied models for understanding how bacteria manage DNA replication stress (RS). These bacteria employ various strategies to detect and stabilize stalled replication forks (RFs), circumvent or bypass lesions, resolve replication-transcription conflicts (RTCs), and resume replication. While central features of responses to RS are broadly conserved, distinct mechanisms have evolved to adapt to their complex environments.
View Article and Find Full Text PDFHeterodyne-based light-induced thermoelastic spectroscopy (HLITES) is capable of correcting measurement errors by evaluating the parameters of the quartz tuning fork (QTF). However, the correcting performance of HLITES will deteriorate under low concentration levels or laser power due to the weakened QTF transient response. Therefore, we propose an electrical excitation beat-aided LITES (EEBA-LITES), which is realized by optical and electrical excitation to the QTF utilizing the time-division multiplexing technique.
View Article and Find Full Text PDFWhat we believe to be a novel load capacitance matching method is proposed for adjusting the resonant frequency of a quartz tuning fork (QTF) in a multi-QTF-based laser spectroscopy gas sensor for the first time. A sensing system integrating quartz-enhanced photoacoustic spectroscopy (QEPAS) and light-induced thermoelastic spectroscopy (LITES) was constructed to validate the proposed method. In this system, the QEPAS module consists of QTF1, while the LITES module is based on QTF2.
View Article and Find Full Text PDFNucleic Acids Res
August 2025
Department of Cardiology of The Second Affiliated Hospital and Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou 310058, China.
Riboswitches are conserved non-coding RNA domains predominantly located at the 5'-end of the bacterial mRNAs, serving as gene expression regulators. Recently, a third class of 2'-deoxyguanosine riboswitch (2'-dG-III) has been identified from guanine riboswitch family, exhibiting comparable binding affinity toward 2'-dG, guanine, and guanosine. To elucidate the unique ligand recognition mechanism of this riboswitch, we solved its crystal structures in complex with different purine derivatives, including 2'-dG, guanine, and guanosine.
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