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Frequency stabilization can overcome the dependence of resonance frequency on amplitude in nonlinear microelectromechanical systems, which is potentially useful in nonlinear mass sensor. In this paper, the physical conditions for frequency stabilization are presented theoretically, and the influence of system parameters on frequency stabilization is analyzed. Firstly, a nonlinear mechanically coupled resonant structure is designed with a nonlinear force composed of a pair of bias voltages and an alternating current (AC) harmonic load. We study coupled-mode vibration and derive the expression of resonance frequency in the nonlinear regime by utilizing perturbation and bifurcation analysis. It is found that improving the quality factor of the system is crucial to realize the frequency stabilization. Typically, stochastic dynamic equation is introduced to prove that the coupled resonant structure can overcome the influence of voltage fluctuation on resonance frequency and improve the robustness of the sensor. In addition, a novel parameter identification method is proposed by using frequency stabilization and bifurcation jumping, which effectively avoids resonance frequency shifts caused by driving voltage. Finally, numerical studies are introduced to verify the mass detection method. The results in this paper can be used to guide the design of a nonlinear sensor.
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http://dx.doi.org/10.3390/mi12020178 | DOI Listing |
Hum Reprod Open
August 2025
Department of Clinical Laboratory, Institute of Translational Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.
Study Question: Do social determinants of health (SDoH) influence the age at menopause among women?
Summary Answer: In our study, adverse SDoH, particularly family low income-to-poverty ratio (PIR), low education level, and the marital status of being widowed, are associated with earlier age at menopause.
What Is Known Already: Some prior studies have considered certain SDoH variables (such as educational attainment and marital status) as potential factors influencing age at menopause, but systematic evidence clearly defining the relationship between multidimensional SDoH and menopausal age remains lacking.
Study Design Size Duration: This cross-sectional analysis included 6083 naturally menopausal women from 10 cycles (1999-2018) of the United States National Health and Nutrition Examination Survey (NHANES) and excluded cases of surgical menopause.
Environ Epigenet
May 2025
Université Grenoble Alpes, INSERM U1209, CNRS UMR 5309, Institut pour l'Avancée des Biosciences (IAB), Team of Environmental Epidemiology Applied to Development and Respiratory Health, 38000 Grenoble, France.
An increasing number of epigenome-wide association studies report tobacco smoking-associated DNA methylation levels. However, comprehensive replication studies remain scarce, particularly in placenta, despite their crucial interest in such a large-scale context. Using DNA methylation data from the EPIC array of 341 new placentas (85 smokers, 219 non-smokers, and 37 former smokers) from the EDEN cohort, we used a candidate approach to replicate maternal smoking-associated CpGs and regions previously identified using the 450K array, and an exploratory approach to discover new associations within EPIC-specific CpGs.
View Article and Find Full Text PDFSmall ruminant lentiviruses (SRLVs) are chronic and progressive diseases caused by retroviruses that pose a serious threat to family farming. This study aimed to determine the seroprevalence and risk factors associated with SRLV infection in goats from family farming properties in Alagoas, Northeastern Brazil. In the semiarid region of Alagoas, seventeen family farming properties were visited, distributed across eleven municipalities.
View Article and Find Full Text PDFHead Face Med
September 2025
Department of Oral and Maxillofacial Surgery, University Hospital Tübingen, Tübingen, Germany.
Background: The treatment of mandibular angle fractures remains controversial, particularly regarding the method of fixation. The primary aim of this study was to compare surgical outcomes following treatment with 1-plate versus 2-plate fixation across two oral and maxillofacial surgery clinics. The secondary aim was to evaluate associations between patient-, trauma-, and procedure-specific factors with postoperative complications and to identify high-risk patients for secondary osteosynthesis.
View Article and Find Full Text PDFLight Sci Appl
September 2025
State Key Laboratory of Quantum Optics Technologies and Devices, Institute of Opto-Electronics, Shanxi University, 030006, Taiyuan, China.
The dominant technical noise of a free-running laser practically limits bright squeezed light generation, particularly within the MHz band. To overcome this, we develop a comprehensive theoretical model for nonclassical power stabilization, and propose a novel bright squeezed light generation scheme incorporating hybrid power noise suppression. Our approach integrates broadband passive power stabilization with nonclassical active stabilization, extending the feedback bandwidth to MHz frequencies.
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