This experimental study concerns the occurrence of biphasic pulses generated during tunable resistive pulse sensing (TRPS) of 200 nm carboxylate polystyrene spheres. In TRPS, a short-lived pulse in ionic current is observed when an individual colloid passes through a pore which separates two fluid reservoirs. The pulse is conventionally resistive, but conductive pulses are observed under certain experimental conditions, as well as biphasic pulses which include both resistive and conductive components. The experimental variables investigated here include the concentration of the phosphate-buffered saline electrolyte, particle charge, pore size, applied voltage, and the direction of particle motion. The onset upper electrolyte concentration for biphasic pulses in TRPS is ∼50 mM, and the ordering of biphasic pulse components can be interpreted using ionic concentration polarization if the conductive component is generated when the particle is in the ion depletion region. Besides providing fundamental understanding, the results are important for the TRPS technique, which is becoming widely used for particle-by-particle measurements of submicron colloids.
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http://dx.doi.org/10.1021/acs.jpcb.5b00344 | DOI Listing |
J Neural Eng
January 2025
Department of Physiology and Department of Electrical and Computer System Engineering, Monash University - Clayton Campus, Wellington Rd, Melbourne, Victoria, 3800, AUSTRALIA.
Development of cortical visual prostheses requires optimization of evoked responses to electrical stimulation to reduce charge requirements and improve safety, efficiency, and efficacy. One promising approach is timing stimulation to the local field potential (LFP), where action potentials have been found to occur preferentially at specific phases. To assess the relationship between electrical stimulation and the phase of the LFP, we recorded action potentials from primary (V1) and secondary (V2) visual cortex in marmosets while delivering single-pulse electrical microstimulation at different phases of the local field potential.
View Article and Find Full Text PDFNeuromodulation
January 2025
Department of Psychiatry and Behavioral Sciences, Division of Child and Adolescent Psychiatry, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA.
Objectives: Biphasic sinusoidal repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation treatment that has been approved by the US Food and Drug Administration for treatment-resistant depression (TRD). Recent advances suggest that standard rTMS may be improved by altering the pulse shape; however, there is a paucity of research investigating pulse shape, owing primarily to the technologic limitations of currently available devices. This pilot study examined the feasibility, tolerability, and preliminary efficacy of biphasic and monophasic rectangular rTMS for TRD.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Developmental Epileptology, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
Seizures elicited by corneal 6-Hz stimulation are widely acknowledged as a model of temporal lobe seizures. Despite the intensive research in rodents, no studies hint at this model in developing animals. We focused on seven age groups of both male and female rats.
View Article and Find Full Text PDFTalanta
December 2024
Hyphenated Mass Spectrometry Laboratory, Faculty of Science, University of Technology Sydney, PO Box 123, Broadway, 2007 NSW, Australia; School of Life Sciences, Faculty of Science, University of Technology Sydney, PO Box 123, Broadway, 2007 NSW, Australia.
The importance of sample preparation selection if often overlooked particularly for untargeted multi-omics approaches that gained popularity in recent years. To minimize issues with sample heterogeneity and additional freeze-thaw cycles during sample splitting, multiple -omics datasets (e.g.
View Article and Find Full Text PDFJ Neurophysiol
December 2024
Spinal Cord Injury Research Centre, Neuroscience Research Australia, Randwick, 2031 NSW, Australia.
Introduction: Lumbar transcutaneous spinal cord stimulation (TSS) evokes synchronized muscle responses, termed spinally evoked motor response (sEMR). Whether the structures TSS activates to evoke sEMRs differ when TSS intensity and waveform are varied is unknown.
Methods: In 15 participants (9F:6M), sEMRs were evoked by TSS over L1-L3 (at sEMR threshold and suprathreshold intensities) using conventional (one 400-µs biphasic pulse) or high-frequency burst (ten 40-µs biphasic pulses at 10 kHz) stimulus waveforms in vastus medialis (VM), tibialis anterior (TA) and medial gastrocnemius (MG) muscles.
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