Bifidobacterium animalis subsp. lactis A6 attenuates hippocampal damage and memory impairments in an ADHD rat model.

Attention deficit hyperactivity disorder (ADHD) is commonly accompanied by learning and memory deficits. This study aimed to demonstrate the effects of probiotic Bifidobacterium animalis subsp. lactis A6 (BAA6) on behaviour and memory function in spontaneously hypertensive rats (SHRs). The results showed that BAA6 treatment ameliorated spatial working memory deficits and inhibited hippocampal neuron loss in SHRs. The levels of neurotransmitters such as acetylcholine, dopamine, and norepinephrine, and the brain derived neurotrophic factor increased and that of glutamate decreased in the brain tissue of SHRs after BAA6 administration. Moreover, BAA6 reduced the levels of pro-inflammatory cytokines TNF-α and IL-1ß, and increased the levels of anti-inflammatory IL-10 and antioxidant glutathione in SHRs. 16S rRNA high-throughput sequencing showed that BAA6 treatment changed the gut microbiota composition. BAA6 promoted beneficial Lactobacillus, Romboutsia, Blautia, and Turicibacter, and decreased the enrichment of bacterial genera such as Dietzia, Sporosarcina, Brevibacterium, NK4A214_group, Atopostipes, and Facklamia negatively associated with neurotransmitter release and anti-inflammatory effects in SHRs. Together, these results suggested that BAA6 improved memory function by ameliorating hippocampal damage, abnormal neurotransmitter release and cerebral inflammation by reshaping the gut microbiota in SHRs. This study provides a scientific basis for the development and application of BAA6 as a promising dietary intervention to reduce the risk of ADHD.

Influence of Temperature during Freeze-Drying Process on the Viability of Bifidobacterium longum BB68S.

Maintaining optimum temperature during freeze-drying is crucial to ensuring the viability of strains. In this study, we evaluated the effect of pre-freezing, sublimation and desorption temperatures on the viability of Bifidobacterium longum BB68S (BB68S). Moreover, we examined the water content, water activity, enzyme activities, and scanning electron microscope of BB68S to explore mechanisms underpinning the effect of temperature on viability. Our analyses revealed the highest survival rates of BB68S collected after pre-freezing and sublimation drying at -40 °C (94.9 ± 2.2%) and -10 °C (65.4 ± 3.8%), respectively. Additionally, response surface methodology demonstrated that the optimum conditions for freeze-drying of BB68S were pre-freezing temperature at -45.52 °C and sublimation temperature at -6.58 °C, and the verification test showed that survival rates of BB68S could reach 69.2 ± 3.8%. Most of the vitality loss occurred during the sublimation drying phase. Further studies showed that different sublimation temperatures affected water content and activity, ß-galactosidase, lactate dehydrogenase, Na+-K+-ATP and Ca2+-Mg2+-ATP activities. In conclusion, the temperature during freeze-drying, especially sublimation temperature, is a key factor affecting the survival rate of BB68S, and the vitality loss during freeze-drying process might be due to compromised cell membrane integrity and permeability.

China's First Demonstration of Cobalt-rich Manganese Crust Thickness Measurement in the Western Pacific with a Parametric Acoustic Probe.

Cobalt-rich manganese crusts (CRCs) are important as a potential mineral source that could occur throughout the Pacific on seamounts, ridges, and plateaus. We built a prototype parametric acoustic probe to complete the task of in-situ thickness measurements to estimate the volumetric distribution of deep-sea mineral. The prototype is designed with dual-channels for receiving the primary and secondary signal, which lays a foundation for improving the thickness extraction algorithm. Considering that the signal quality is degraded by the system interference and ambient noise, some improvements to the algorithm are proposed by including the wavelet-based envelope extraction method and the adaptive estimation strategy based on the dual-channel information. Additionally, wavelet regression is applied to reduce the measuring noise assuming that the CRCs have local thickness invariability. The algorithm is suitable for the CRCs with the structure of the multilayers at the top surface and one single layer at the bottom surface. A laboratory experiment is performed to validate the effectiveness of the algorithm. The experiments carried out on the China Ocean 51th voyage in the Western Pacific Ocean on Aug 30, 2018, are described and the data obtained by using the sit-on-bottom stationary measurement are processed to validate the design of the prototype.

Objective and subjective evaluations of the Nurotron Venus cochlear implant system via animal experiments and clinical trials.

CONCLUSION: This study described objective and subjective evaluations of the Nurotron® Venus™ Cochlear Implant System and indicated that this system produced a satisfactory performance. OBJECTIVE: To observe the performance of the Nurotron® Venus™ cochlear implant (CI) system via electrophysiological and psychophysical evaluations. METHODS: A 26-electrode CI system was specially designed. The performance of MRI in animal and cadaveric head experiments, EABR in cats experiment, the correlation between ESRT and C level, and psychophysics evaluations in clinical trials were observed. RESULTS: In the animal and cadaveric head experiments, magnet dislocation could not be prevented in the 1.5 T MRI without removal of the internal magnet. The EABR was clearly elicited in cat experiment. In the clinical trial, the ESRT was strongly correlated with C level (p < 0.001). The human clinical trial involving 57 post-lingually deafened native Mandarin-speaking patients was performed. Residual hearing protection in the implanted ear at each audiometric frequency was observed in 27.5-46.3% patients post-operatively. A pitch ranking test revealed that place pitches were generally ordered from apical to basal electrodes. The recognitions of the perceptions of 301 disyllabic words, environment sounds, disyllabic words, and numerals were significantly better than the pre-operative performance and reached plateaus.

Development and evaluation of the Nurotron 26-electrode cochlear implant system.

Although the cochlear implant has been widely acknowledged as the most successful neural prosthesis, only a fraction of hearing-impaired people who can potentially benefit from a cochlear implant have actually received one due to its limited awareness, accessibility, and affordability. To help overcome these limitations, a 26-electrode cochlear implant has been developed to receive China's Food and Drug Administration (CFDA) approval in 2011 and Conformité Européenne (CE) Marking in 2012. The present article describes design philosophy, system specification, and technical verification of the Nurotron device, which includes advanced digital signal processing and 4 current sources with multiple amplitude resolutions that not only are compatible with perceptual capability but also allow interleaved or simultaneous stimulation. The article also presents 3-year longitudinal evaluation data from 60 human subjects who have received the Nurotron device. The objective measures show that electrode impedance decreased within the first month of device use, but was stable until a slight increase at the end of two years. The subjective loudness measures show that electric stimulation threshold was stable while the maximal comfort level increased over the 3 years. Mandarin sentence recognition increased from the pre-surgical 0%-correct score to a plateau of about 80% correct with 6-month use of the device. Both indirect and direct comparisons indicate indistinguishable performance differences between the Nurotron system and other commercially available devices. The present 26-electrode cochlear implant has already helped to lower the price of cochlear implantation in China and will likely contribute to increased cochlear implant access and success in the rest of the world. This article is part of a Special Issue entitled .

A speech enhancement method for cochlear implant listeners.

This paper discusses a single-channel speech enhancement method for cochlear implant listeners. It is assumed that the Fourier Transform coefficients of speech and background noise have different statistical distributions. A statistical-model-based method is adopted to update the signal-to-noise ratio and estimate the background noise so that the musical noise and speech distortion induced by traditional spectral subtraction method can be effectively reduced. This enhancement method was evaluated on seven postlingually deaf Chinese cochlear implant listeners in comparison with other two speech enhancement methods. Test materials were Mandarin sentences corrupted by three different types of background noise. Experimental results showed that the proposed speech enhancement method could benefit the speech intelligibility of Chinese cochlear implant listeners. The results suggest that different noise types may affect the performance of different speech enhancement algorithms.

Musical pitch discrimination by cochlear implant users.

OBJECTIVES: The main goal of this study was to investigate the effects of acoustic characteristics, including timbre and fundamental frequency (F0), on the musical pitch discrimination of cochlear implant users. METHODS: Eight postlingually deafened cochlear implant users were recruited, along with 8 control subjects with normal hearing. Pitch discrimination tests were carried out using test stimuli from 4 musical instruments plus synthetic complex stimuli. Three reference tones with different F0s were used. RESULTS: The mean difference limens were 1.8 to 10.7 semitones in the just-noticeable difference task and 2.1 to 13.6 semitones in the pitch-direction discrimination task for different timbre and F0 combinations. Three-way analysis of variance showed that the acoustic characteristics of the musical stimuli, such as timbre and F0, significantly influenced pitch discrimination performance. CONCLUSIONS: Acoustic characteristics determine the complexity of the electrical stimulation pattern, which directly affects performance in pitch discrimination. A place pattern with a clear and regular low-order harmonic structure is most important for good pitch discrimination. A clear F0-related temporal pattern is also useful when the F0 is low. Pitch perception performance will worsen when there is interference in the high-frequency channels.

Cochlear implants: system design, integration, and evaluation.

As the most successful neural prosthesis, cochlear implants have provided partial hearing to more than 120000 persons worldwide; half of which being pediatric users who are able to develop nearly normal language. Biomedical engineers have played a central role in the design, integration and evaluation of the cochlear implant system, but the overall success is a result of collaborative work with physiologists, psychologists, physicians, educators, and entrepreneurs. This review presents broad yet in-depth academic and industrial perspectives on the underlying research and ongoing development of cochlear implants. The introduction accounts for major events and advances in cochlear implants, including dynamic interplays among engineers, scientists, physicians, and policy makers. The review takes a system approach to address critical issues in cochlear implant research and development. First, the cochlear implant system design and specifications are laid out. Second, the design goals, principles, and methods of the subsystem components are identified from the external speech processor and radio frequency transmission link to the internal receiver, stimulator and electrode arrays. Third, system integration and functional evaluation are presented with respect to safety, reliability, and challenges facing the present and future cochlear implant designers and users. Finally, issues beyond cochlear implants are discussed to address treatment options for the entire spectrum of hearing impairment as well as to use the cochlear implant as a model to design and evaluate other similar neural prostheses such as vestibular and retinal implants.