The contribution of auditory imagery and visual rhythm perception to sensorimotor synchronization with external and imagined rhythm.

Sensorimotor synchronization (SMS) refers to the temporal coordination of an external stimulus with movement. Our previous work revealed that while SMS with visual flashing patterns was less consistent than with auditory or tactile patterns, it was still evident in a sample of nonmusicians. Although previous studies have speculated the potential role of auditory imagery, its contribution to visual SMS performance is not well quantified. Utilizing a synchronization-continuation finger-tapping task with a visual stimulus that included implied motion, we aimed to examine how participants' imagery ability, musicality, and rhythm perception affected SMS performance. We quantified participants' SMS consistency in synchronization (with visual cues) and continuation (without visual cues) phases. Participants also performed a perception task assessing their ability to detect temporal perturbations in the visual rhythm and completed musical ability and imagery questionnaires. Our linear regression model for SMS consistency included the trial phase, self-reported auditory imagery control and musicality, and visual rhythm perception as predictors. Significant effects of trial phase and auditory imagery scores on SMS consistency suggested that participants performed SMS more consistently while the guiding visual stimulus was present and that the higher one's self-reported auditory imagery ability, the better their SMS when continuing with unguided rhythm. One's visual rhythm perception accuracy significantly correlated with SMS consistency during the synchronization phase, and there was no correlation between rhythm perception and auditory imagery control. Overall, our results suggested relatively independent contributions of auditory imagery and visual rhythm perception to SMS with visual rhythm. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Alkaline surface treatment and time-resolved reading of mn-doped nanocrystal signal transducer for enhanced bioassay sensitivity.

Recently, Mn-doped semiconductor nanocrystals (NCs) with high brightness, long lifetimes, and low-energy excitation are emerging for time-resolved luminescence biosensing/imaging. Following our previous work on Mn-doped NCs, in this work we developed poly(styrene-co-maleic anhydride) (PSMA)-encapsulated Mn-doped AgZnInS/ZnS NCs as signal transducers for immunoassay of capsular polysaccharide (CPS), a surface antigen and also a biomarker of Burkholderia pseudomallei which causes a fatal disease called melioidosis. To enhance the assay sensitivity, a surface treatment for PSMA-encapsulated NCs (NC-probes) was performed to promote the presence of carboxyl groups that help conjugate more anti-CPS antibodies to the surface of NC-probes and thus enhance bioassay signals. Meanwhile, time-resolved reading on the luminescence of NC-probes was adopted to minimize the assay background autofluorescence. Both strategies essentially enhance the assay signal-to-background ratio (or equivalently the assay sensitivity) by increasing the signal and decreasing the background, respectively. Through performing and comparing immunoassays with different NC-probes (with and without surface treatment) and different signal reading methods (time-resolved reading and non-time-resolved reading), it was proven that the immunoassay adopting surface-treated NC-probes and time-resolved reading achieved a lower limit-of-detection (LOD) than the ones adopting non-surface-treated NC-probes or non-time-resolved reading. Moreover, the achieved LOD is comparable to the LOD of immunoassay using enzyme horseradish peroxidase as a signal transducer.

Review of Mn-Doped Semiconductor Nanocrystals for Time-Resolved Luminescence Biosensing/Imaging.

Colloidal semiconductor nanocrystals (NCs) have been developed for decades and are widely applied in biosensing/imaging. However, their biosensing/imaging applications are mainly based on luminescence-intensity measurement, which suffers from autofluorescence in complex biological samples and thus limits the biosensing/imaging sensitivities. It is expected for these NCs to be further developed to gain luminescence features that can overcome sample autofluorescence. On the other hand, time-resolved luminescence measurement utilizing long-lived-luminescence probes is an efficient technique to eliminate short-lived autofluorescence of samples while recording time-resolved luminescence of the probes for signal measurement after pulsed excitation from a light source. Despite time-resolved measurement being very sensitive, the optical limitations of many of the current long-lived-luminescence probes cause time-resolved measurement to be generally performed in laboratories with bulky and costly instruments. In order to apply highly sensitive time-resolved measurement for in-field or point-of-care (POC) testing, it is essential to develop probes possessing high brightness, low-energy (visible-light) excitation, and long lifetimes of up to milliseconds. Such desired optical features can significantly simplify the design criteria of time-resolved measurement instruments and facilitate the development of low-cost, compact, sensitive instruments for in-field or POC testing. Mn-doped NCs have recently been in rapid development and provide a strategy to solve the challenges faced by both colloidal semiconductor NCs and time-resolved luminescence measurement. In this review, we outline the major achievements in the development of Mn-doped binary and multinary NCs, with emphasis on their synthesis approaches and luminescence mechanisms. Specifically, we demonstrate how researchers approached these obstacles to achieve the aforementioned desired optical properties on the basis of the progressive understanding of Mn emission mechanisms. Afterward, we review representative applications of Mn-doped NCs in time-resolved luminescence biosensing/imaging and present the potential of Mn-doped NCs in advancing time-resolved luminescence biosensing/imaging for in-field or POC testing.