Previous studies have demonstrated that botulinum toxin type A (BoNT-A) attenuates orofacial nociception. However, there has been no evidence of the participation of the voltage-gated sodium channels (Navs) in the antinociceptive mechanisms of BoNT-A. This study investigated the cellular mechanisms underlying the antinociceptive effects of BoNT-A in a male Sprague-Dawley rat model of trigeminal neuropathic pain produced by malpositioned dental implants. The left mandibular second molar was extracted under anesthesia, followed by a miniature dental implant placement to induce injury to the inferior alveolar nerve. Mechanical allodynia was monitored after subcutaneous injection of BoNT-A at 3, 7, or 12 d after malpositioned dental implant surgery. Subcutaneous injections of 1 or 3 U/kg of BoNT-A on postoperative day 3 significantly attenuated mechanical allodynia, although 0.3 U/kg of BoNT-A did not affect the air-puff threshold. A single injection of 3 U/kg of BoNT-A produced prolonged antiallodynic effects over the entire experimental period. Treatment with BoNT-A on postoperative days 7 and 12, when pain had already been established, also produced prolonged antiallodynic effects. Double treatments with 1 U/kg of BoNT-A produced prolonged, more antiallodynic effects as compared with single treatments. Subcutaneous administration of 3 U/kg of BoNT-A significantly inhibited the upregulation of Nav isoform 1.7 (Nav1.7) expression in the trigeminal ganglion in the nerve-injured animals. These results suggest that antinociceptive effects of BoNT-A are mediated by an inhibition of upregulated Nav1.7 expression in the trigeminal ganglion. BoNT-A is therefore a potential new therapeutic agent for chronic pain control, including neuropathic pain.

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Aim To examine the type of vesicular glutamate transporter (VGLUT)‐immunopositive (+) axons that coexpress neuropeptides in the rat and human dental pulp, which may help understand peripheral mechanism of pulpal inflammatory pain in rats and humans. Methodology The trigeminal ganglia (TG) and the dental pulp of the maxillary molar teeth from three male Sprague–Dawley rats weighing 300–330 g and dental pulps of three healthy human (male) maxillary premolar teeth from three 16 to 28‐year‐old patients extracted for orthodontic treatment were used. The type of VGLUT + axons that coexpress substance P (SP)‐ and/or calcitonin gene‐related peptide (CGRP) and parvalbumin in the rat TG and in the axons of the rat and the human dental pulp was examined by double fluorescence immunohistochemistry and quantitative analysis. Results were analyzed using one‐way anova and the Kruskal–Wallis test. Results SP and CGRP were expressed in many human VGLUT1 + pulpal axons but not in the rat VGLUT1 + TG neurons and pulpal axons (P < 0.05). SP and CGRP were expressed in a considerable number of human VGLUT2 + pulpal axons and also in many rat TG neurons and pulpal axons. The fraction of VGLUT1 + axons expressing parvalbumin was about three times higher in the rat than in the human dental pulp (P < 0.05). Conclusions These findings suggest that the types of VGLUT + axons, which release neuropeptides, may be different between the rat and the human dental pulp, raising a possibility that peripheral mechanism of pulpal inflammatory pain may be different between rats and humans.

Active noise cancellation (ANC) is the most important function in an audio device because it removes unwanted ambient noise. As many audio devices are increasingly equipped with digital signal processing (DSP) circuits, the need for low-power and high-performance processors has arisen because of hardware resource restrictions. Low-power design is essential because wireless audio devices have limited batteries. Noise cancellers process the noise in real time, but they have a short secondary path delay in conventional least mean square (LMS) algorithms, which makes implementing high-quality ANC difficult. To solve these problems, we propose a fixed-filter noise cancelling system with a convolutional neural network (CNN) classification algorithm to accommodate short secondary path delay and reduce the noise ratio. The signal-to-noise ratio (SNR) improved by 2.3 dB with CNN noise cancellation compared to the adaptive LMS algorithm. A frequency-domain noise classification and coefficient selection algorithm is introduced to cancel the noise for time-varying systems. Additionally, our proposed ANC architecture includes an even–odd buffer that efficiently computes the fast Fourier transform (FFT) and overlap-save (OLS) convolution. The simulation results demonstrate that the proposed even–odd buffer reduces processing time by 20.3% and dynamic power consumption by 53% compared to the single buffer.

A new of vibration transducer, a DFMT (differential floating mass type) is introduced for use in an ME1 (middle ear implant) system The DFMT transducer is not influenced by external noise magnetic flux and has a very high vibration efticiency because its two magnets, which are glued back to back with the same poles facing, are located in the coil.