We report on the measurement of the high frequency properties of a planar Penning ion trap fabricated on a chip. Two types of chips have been measured: the first manufactured by photolithographic metal deposition on a p-doped silicon substrate and the second made with printed circuit board technology on an alumina substrate. The input capacitances and the admittances between the different trap's electrodes play a critical role in the electronic detection of the trapped particles. The measured input capacitances of the photolithographic chip amount to 65-76 pF, while the values for the printed circuit board chips are in the range of 3-5 pF. The latter are small enough for detecting non-destructively a single trapped electron or ion with a specifically tuned LC resonator. We have also measured a mutual capacitance of ∼85 fF between two of the trap's electrodes in the printed circuit board chip. This enables the detection of single, or very few, trapped particles in a broader range of charge-to-mass ratios with a simple resistor on the chip. We provide analytic calculations of the capacitances and discuss their origin and possible further reduction.
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http://dx.doi.org/10.1063/5.0091745 | DOI Listing |
ACS Sens
January 2025
Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384, PR China.
The simultaneous detection of electroencephalography (EEG) signals and neurotransmitter levels plays an important role as biomarkers for the assessment and monitoring of emotions and cognition. This paper describes the development of boron and nitrogen codoped graphene-diamond (BNGrD) microelectrodes with a diameter of only 200 μm for sensing EEG signals and dopamine (DA) levels, which have been developed for the first time. The optimized BNGrD microelectrode responded sensitively to both EEG and DA signals, with a signal-to-noise ratio of 9 dB for spontaneous EEG signals and a limit of detection as low as 124 nM for DA.
View Article and Find Full Text PDFFront Bioeng Biotechnol
January 2025
Department of Neurological Surgery, The Ohio State University, Columbus, OH, United States.
Background: Diabetic peripheral neuropathy (DPN) is a common complication of diabetes. Proactive treatment options remain limited, which is exacerbated by a lack of sensitive and convenient diagnostics, especially early in disease progression or specifically to assess small fiber neuropathy (SFN), the loss of distal small diameter axons that innervate tissues and organs.
Methods: We designed, fabricated, tested, and validated a first-of-its-kind medical diagnostic device for the functional assessment of transdermal small fiber nerve activity.
Microsyst Nanoeng
January 2025
Henry Samueli School of Engineering, University of California, Irvine, CA, USA.
In recent decades, electrokinetic handling of microparticles and biological cells found many applications ranging from biomedical diagnostics to microscale assembly. The integration of electrokinetic handling such as dielectrophoresis (DEP) greatly benefits microfluidic point-of-care systems as many modern assays require cell handling. Compared to traditional pump-driven microfluidics, typically used for DEP applications, centrifugal CD microfluidics provides the ability to consolidate various liquid handling tasks in self-contained discs under the control of a single motor.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, QC, H3G 1M8, Canada. Electronic address:
Waste printed circuit boards (WPCBs) are a significant component of electronic waste (e-waste) and are among the fastest-generating waste flows. The potentially negative impacts caused by e-waste on the environment and human health pose an increasingly apparent threat to people's everyday lives and well-being. The nonmetallic fraction (predominantly carbon) of WPCBs is characterized by heavy weight, low resource value, and complex composition, and these characteristics significantly restrict the recycling of the WPCBs to achieve a circular economy.
View Article and Find Full Text PDFSensors (Basel)
January 2025
School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 611731, China.
Lithium-ion batteries represent a significant component of the field of energy storage, with a diverse range of applications in consumer electronics, portable devices, and numerous other fields. In view of the growing concerns about the safety of batteries, it is of the utmost importance to develop a sensor that is capable of accurately monitoring the internal temperature of lithium-ion batteries. External sensors are subject to the necessity for additional space and ancillary equipment.
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