Session Detail

Body-worn hearing aids are one of the most common assistive-hearing devices for individuals with hearing difficulties. It mainly integrates microphones, speakers, and signal-processing units to enhance the acoustic signals thereby improving the audibility for hearing-impaired individuals. Previous studies have shown that the pocket aid benefits the users; however, there is still room for improvement, such as reduction of rubbing noise. Mechanism design and application of acoustic absorbing damping material are common approaches for solving this issue; however, such approaches offer limited improvement. Therefore, a suitable signal-processing method, such as the deep-denoising autoencoder (DDAE), could be used to further reduce the rubbing noise. The experimental results show that the DDAE provides higher perceptual evaluation of speech quality and extended short-time objective intelligibility than the classical noise reduction (NR) approach. Moreover, multi-objective learning-based DDAE can achieve higher performance than DDAE NR. These results suggest that the deep-learning-based NR could be used to further improve the benefits for body-worn hearing aid users.

 

Circulating tumor cells (CTCs) are biomarkers for the detec-tion, diagnosis, and monitoring of cancer which could offer biological information required for the development of person-alized medicine. However, the specific catch and nondestructive release of CTCs from million blood cells remain technically challenging. Here, we present a system to studying CTC catch and release efficiency by a disulfide-containing poly(carboxybetaine methacrylate) (poly(CBMA)) hydrogel. We used disulfide-contained crosslinkers to form poly(CBMA) hydrogel which potentially inhibited the adhesion of tumor cells and blood cells. After conjugation of 50 g/mL anti-epithelial cell adhesion molecule (anti-EpCAM) antibodies via carbodiimide reaction, we found that the capture efficiency of tumor cells reached a maximum. The system was further vali-dated by isolation co-spiked tumor cells in healthy human blood. The results shows that the system provided the captur-ing ability of tumor cell in blood, and the tumor cells were further recovered without injury after the disulfide linkage in the poly(CBMA) hydrogel was broken by an addition of L-cysteine.

 

We investigate the neurovascular functions during hyperacute, focal ischemia in a small-animal photothrombotic ischemia (PTI) model following recombinant tissue plasminogen activator (rtPA) thrombolysis. We employ a custom-designed electrocorticogram (ECoG) - functional photoacoustic microscopy (fPAM) imaging system (i.e., ECoG-fPAM) for probing the hyperacute ischemic neurovascular functions. Our study demonstrated for the first time the simultaneous changes in neural activity (i.e., somatosensory-evoked potential (SSEP), resting-state (RS) ECoG related indicators (i.e., inter-hemispheric coherence, alpha-delta ratio (ADR) and brain symmetry index (BSI)) and the cerebral hemodynamic responses (i.e., cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO2)) at different rtPA infusion onset times post PTI. Our experimental model and corresponding data will serve as a benchmark to explore ischemic neurovascular mechanisms and to study potential interventions for bettering stroke treatment outcomes.

 

Three-dimensional (3D) cell culture models have become powerful tools in cancer research, as they better simulate the in vivo physiological microenvironment than traditional two-dimensional (2D) cell cultures. Tumor cells cultured in a 3D system as multicellular tumor spheroids (MTS) recapitulate several critical in vivo characteristics that allow the study of biological functions and drug discovery. Microwell technology is best platform for generating MTS as it provides geometrically defined microstructures for culturing size-controlled MTS amenable for various downstream functional assays. This work presents a simple and economical microwell fabrication methodology that be conveniently incorporated into the conventional workflow used to generate MTS. The microwells were 400–700 µm in diameter, and hepatic MTS cultured in them for up to 5 days grew to 250–520 µm with good viability and shape. To demonstrate the ability to integrate the microwell fabrication with a high-throughput workflow using the conventional multi-well plate system, a conventional 96-well plate was employed for proof-of-concept drug screening. The relative fluorescence intensity showed an eight-fold reduction in cell viability, confirming the feasibility of photothermal treatment as a potential therapeutic intervention. In conclusion, using the microwell platform to generate MTS may be an effective tool for discovering therapeutic modalities for cancer treatment.

 

Traditional diagnosis of lung cancer is through histolog-ical examination. However, due to the fact that cells are three-dimensional, objective determination of the two-dimensional nucleus to cytoplasm (N/C) ratio remains a challenge. In this work, we used two-photon microscopy to acquired three-dimensional images of normal human lung cell line Beas2B, human lung adenocarcinoma CL1-0 and CL1-5 cell lines. Based on an automated algorithm, we calculated N/C ratios in two- and three-dimensions. Over all, we found that 3D N/C ratio is less susceptible to variations to cell sizes than 2D N/C ratio in discriminat-ing normal and cancer cells. Moreover, our algorithm removes ambiguity in determination of N/C ratios and may be applied in the clinical setting for objective deter-mination of this important parameter used in clinical diagnosis.

 

In this study, we utilized Holo-Hilbert spectral analysis (HHSA) to investigate the amplitude-modulated (AM) and frequency-modulated (FM) in oscillatory activities, induced by slow- and fast-rate repetitive movements. The proposed HHSA approach which is based on 2-layer empirical mode decomposition (EMD) approach provided full-informational spectral information. We observed that the modulation power induced by slow-rate movements was significantly higher than that induced by fast-rate movements. The AM frequencies in alpha band with slow-rate movements were higher than with fast-rate movements. The difference between slow-rate and fast-rate movements might be caused by the change of motor functional modes (from default mode network (DMN) to automatic mode). The HHSA for oscillatory activity analysis could provide informative interaction among different frequency bands.

 

Hydrogel-based electronics are ideally suited for neural interfaces because they exhibit ultracompliant mechanical properties that match that of excitable tissue in the brain and peripheral nerve. Hydrogel-based multielectrode arrays (MEA) can conformably interface with tissues to minimize inflammation and improve the reliability to enhance signal transduction. However, MEA substrates composed of swol-len hydrogels exhibit low toughness and low adhesion stabil-ity when laminated on the tissue surface and also present technical challenges for processes commonly employed in MEA fabrication. Here, we describe a new strategy to fabri-cate ultracompliant MEA based on aqueous-phase transfer printing. This technique employs redox active adhesive mo-tifs in hygroscopic polymer precursors that simultaneously form hydrogels through sol-gel phase transitions and bond to underlying microelectronic structures. Specifically, in situ gelation of 4-arm-polyethylene glycol-grafted catechol [PEG-Dopa]4 hydrogels induced by oxidation using Fe3+ produces conformal adhesive contact with the underlying MEA, robust adhesion to electronic structures, and rapid dissolution of water-soluble sacrificial release layers. MEA are then integrated on hydrogel-based substrates to produce free standing ultracompliant neural probes, which are then laminated to the surface of the dorsal root ganglia in feline subjects to record single-unit neural activity.