Near infrared light-responsive and drug-loaded black phosphorus nanosheets for antibacterial applications.

The management of wound infection remain a major global challenge, effectively ablation of bacteria is of significant in fighting wound infectious diseases. Herein, black phosphorus nanosheets (BPNSs) were successfully prepared by liquid phase exfoliation technology, and composite nanosheets (BPNSs@phy) were formed by loading antimicrobial physcion（Phy）via hydrophobic interaction. Studies have shown that BPNSs@phy has good stability and low cytotoxicity under physiological conditions. In addition, BPNSs@phy has excellent photothermal conversion ability. After the irradiation of 808 nm near-infrared light, the light energy is converted into heat to promote the release of physcion. Under the synergistic effect of photothermal therapy (PTT) and antibacterial agents, BPNSs@phy has an excellent bactericidal effect against S.aureus (99.7%) and P.aeruginosa (99.9%). This study is expected to provide a new strategy for the development of BPNSs based antibacterial materials.

Neural oscillations associated with auditory duration maintenance in working memory.

The neural representation of auditory duration remains unknown. Here, we used electroencephalogram (EEG) recordings to investigate neural oscillations during the maintenance of auditory duration in working memory (WM). EEG analyses indicated that the auditory duration length was not associated with changes in the theta band amplitude, whereas the alpha band amplitudes during 3-s and 4-s auditory duration conditions were lower than during the 1-s and 2-s conditions. Moreover, the alpha band amplitude and accuracy were positively correlated in the 2-s duration condition. We also found that the neural representation of auditory duration is segmented, with a critical threshold point of approximately 2 s, which is shorter than that for visual duration (3 s). The results emphasised the involvement of the alpha band in auditory duration maintenance in WM. Our study's findings indicate that different internal representations of auditory durations are maintained in WM below and above 2 s from the perspective of electrophysiology. Additionally, the critical threshold point is related to the sensory modality of duration.

Differences in the neural basis of automatic auditory and visual time perception: ERP evidence from an across-modal delayed response oddball task.

In our everyday lives, we need to process auditory and visual temporal information as efficiently as possible. Although automatic auditory time perception has been widely investigated using an index of the mismatch negativity (MMN), the neural basis of automatic visual time perception has been largely ignored. The present study investigated the automatic processing of auditory and visual time perception employing the cross-modal delayed response oddball paradigm. In the experimental condition, the standard stimulus was 200 ms and the deviant stimulus was 120 ms, which were exchanged in the control condition. Reaction time, accuracy, and event-related potential (ERP) data were measured when participants performed the duration discrimination task. The ERP results showed that the MMN, N2b, and P3 were elicited by an auditory deviant stimulus under the attention condition, while only the MMN was elicited under the inattention condition. The MMN was largest over the frontal and central sites, while the difference in MMN amplitude was not significant between under the attention and inattention condition. In contrast, the change-related positivity (CRP) and the visual mismatch negativity (vMMN) were elicited by the visual deviant stimulus under both the attention and inattention conditions. The CRP was largest over the occipito-temporal sites under the attention condition and over the fronto-central sites under the inattention condition. The difference in CRP amplitude was significant between the attention and inattention condition. The vMMN was largest over the parieto-occipital sites under the attention condition, and largest over the fronto-central sites under the inattention condition. The difference in vMMN amplitude was significant between the attention and inattention condition. Auditory MMN does not appear to be modulated by attention, whereas the visual CRP and the vMMN are modulated by attention. Therefore, the present study provides electrophysiological evidence for the existence of automatic visual time perception and supports an "attentional switch" hypothesis for a modality effect on duration judgments, such that auditory temporal information is processed relatively automatically, whereas visual temporal information processing requires controlled attention.

An event-related potential study of temporal information encoding and decision making.

This research used event-related potentials to investigate the time course of temporal information encoding and decision making. Participants performed auditory temporal and pitch discrimination tasks within a S1-S2 matching paradigm, wherein two stimuli (S1-S2) are presented sequentially, and S2 is either the same as or different from S1. Event-related potentials results showed N1, P2 and contingent negative variation (CNV) amplitudes were higher during encoding than decision making. During the encoding phase, N1 and P2 amplitudes were lower in the temporal task than the pitch task. During the decision-making phase, the CNV amplitude was higher in the temporal task. Findings suggest N1, P2 and CNV are related to temporal encoding, albeit only CNV is related to temporal decision making.