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An inexpensive digital microfluidic (DMF) chip was fabricated by screen-printing electrodes on a sheet of polyimide. This device was manually integrated with surface acoustic wave nebulization (SAWN) MS to conduct hydrogen/deuterium exchange (HDX) of peptides. The HDX experiment was performed by DMF mixing of one aqueous droplet of angiotensin II with a second containing various concentrations of D2O. Subsequently, the degree of HDX was measured immediately by SAWN-MS. As expected for a small peptide, the isotopically resolved mass spectrum for angiotensin revealed that maximum deuterium exchange was achieved using 50% D2O. Additionally, using SAWN-MS alone, the global HDX kinetics of ubiquitin were found to be similar to published NMR data and back exchange rates for the uncooled apparatus using high inlet capillary temperatures was less than 6%.
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http://dx.doi.org/10.1016/j.chroma.2015.12.048 | DOI Listing |
J Phys Chem Lett
September 2025
Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States.
Carbon dots (CDs) represent a new class of nontoxic and sustainable nanomaterials with increasing applications. Among them, bright and large Stokes-shift CDs are highly desirable for display and imaging, yet the emission mechanisms remain unclear. We obtained structural signatures for the recently engineered green and red CDs by ground-state femtosecond stimulated Raman spectroscopy (FSRS), then synthesized orange CDs with similar size but much higher nitrogen dopants than red CDs.
View Article and Find Full Text PDFJ Acoust Soc Am
September 2025
Department of Physics, University of Louisiana at Lafayette, Lafayette, Louisiana 70503, USA.
A method is presented for determining the significant parameters, maximum wind speed and radius of maximum wind speed, of the surface winds associated with a hurricane. The method is based on Bayesian inversion, using Markov chain Monte Carlo sampling. Underwater acoustic measurements are used to estimate parameters in the axisymmetric Holland model for hurricane surface winds.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
September 2025
Anhui Province Key Laboratory for Control and Applications of Optoelectronic Information Materials, School of Physics and Electronic Information, Anhui Normal University, Wuhu, Anhui 241000, China.
An integrated miniature time-of-flight mass spectrometer (TOF-MS) system coupled with a pocket-size 3D-printed laser-induced acoustic desorption (LIAD) source is described. This 3D-printed LIAD source utilizes only a miniature deceleration motor to achieve two-dimensional motion of the target surface, simplifying the source structure and improving the long-term stability of mass spectrometry measurements. It has been successfully applied to analyze the model molecule creatinine and ingredients in an energy beverage (Red Bull), where main natural nutrients were clearly identified.
View Article and Find Full Text PDFIEEE Trans Biomed Eng
September 2025
Objective: Transcranial ultrasound (US) stimulation (TUS) has emerged as a promising technique for minimally invasive, localized, deep brain stimulation. However, indirect auditory effects during neuromodulation require careful consideration, particularly in experiments with rodents. One method to prevent auditory responses involves applying tapered envelopes to US bursts.
View Article and Find Full Text PDFJASA Express Lett
September 2025
IEMN (UMR CNRS 8520), University Polytechnique Hauts-de-France, CNRS, University Lille, INSA HdF, F-59313 Valenciennes,
This study presents a non-destructive method for estimating surface acoustic wave attenuation, which is highly sensitive to microstructural features, especially at high frequencies. The method uses a single wideband dispersive interdigital transducer (IDT) that remotely emits acoustic waves at the sample's edge. Chirp compression of the temporal displacement response is achieved by correlating the excitation signal with the spatial configuration of the IDT's electrodes.
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