Mechanical properties of carbon fiber/cellulose composite papers modified by hot-melting fibers

AbstractCarbon fiber (CF)/cellulose (CLS) composite papers were prepared by papermaking techniques and hot-melting fibers were used for modification. The mechanical properties of the obtained composite papers with different CF, CLS and hot-melting fiber ratios were studied and further discussed. It is observed that, for both CF/CLS composite papers and those modified by hot-melting fibers, the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show that with the addition of hot-melting fibers, the modified papers exhibit enhanced mechanical performance compared to CF/CLS composite papers. Through SEM characterization, it is confirmed that the improvement of mechanical properties attributes to the reinforcement of adhesive binding at the fiber overlap nodes. Also, through four-probe method, the resistivity and the electrical performance of the modified and unmodified papers were characterized and the result shows that the hot-melting fiber modification brings no harm to the electrical properties

Glutamate Excitotoxicity Inflicts Paranodal Myelin Splitting and Retraction.

Paranodal myelin damage is observed in white matter injury. However the culprit for such damage remains unknown. By coherent anti-Stokes Raman scattering imaging of myelin sheath in fresh tissues with sub-micron resolution, we observed significant paranodal myelin splitting and retraction following glutamate application both ex vivo and in vivo. Multimodal multiphoton imaging further showed that glutamate application broke axo-glial junctions and exposed juxtaparanodal K+ channels, resulting in axonal conduction deficit that was demonstrated by compound action potential measurements. The use of 4-aminopyridine, a broad-spectrum K+ channel blocker, effectively recovered both the amplitude and width of compound action potentials. Using CARS imaging as a quantitative readout of nodal length to diameter ratio, the same kind of paranodal myelin retraction was observed with applications of Ca2+ ionophore A23187. Moreover, exclusion of Ca2+ from the medium or application of calpain inhibitor abolished paranodal myelin retraction during glutamate exposure. Examinations of glutamate receptor agonists and antagonists further showed that the paranodal myelin damage was mediated by NMDA and kainate receptors. These results suggest that an increased level of glutamate in diseased white matter could impair paranodal myelin through receptor-mediated Ca2+ overloading and subsequent calpain activation

Digital Human Interactive Recommendation Decision-Making Based on Reinforcement Learning

Digital human recommendation system has been developed to help customers find their favorite products and is playing an active role in various recommendation contexts. How to timely catch and learn the dynamics of the preferences of the customers, while meeting their exact requirements, becomes crucial in the digital human recommendation domain. We design a novel practical digital human interactive recommendation agent framework based on Reinforcement Learning(RL) to improve the efficiency of the interactive recommendation decision-making by leveraging both the digital human features and the superior flexibility of RL. Our proposed framework learns through real-time interactions between the digital human and customers dynamically through the state-of-art RL algorithms, combined with multimodal embedding and graph embedding, to improve the accuracy of personalization and thus enable the digital human agent to timely catch the attention of the customer. Experiments on real business data demonstrate that our framework can provide better personalized customer engagement and better customer experiences.Comment: 9 pages, 1 figure, 1 table, the paper has been accepted and this is the final camera-ready for NeurIPS 2022 Workshop on Human in the Loop Learning, https://neurips-hill.github.io

Mapping In Vivo Tumor Oxygenation within Viable Tumor by 19F-MRI and Multispectral Analysis

AbstractQuantifying oxygenation in viable tumor remains a major obstacle toward a better understanding of the tumor microenvironment and improving treatment strategies. Current techniques are often complicated by tumor heterogeneity. Herein, a novel in vivo approach that combines 19F magnetic resonance imaging (19F-MRI)R1 mapping with diffusionbased multispectral (MS) analysis is introduced. This approach restricts the partial pressure of oxygen (pO2) measurements to viable tumor, the tissue of therapeutic interest. The technique exhibited sufficient sensitivity to detect a breathing gas challenge in a xenograft tumor model, and the hypoxic region measured by MS 19F-MRI was strongly correlated with histologic estimates of hypoxia. This approach was then applied to address the effects of antivascular agents on tumor oxygenation, which is a research question that is still under debate. The technique was used to monitor longitudinal pO2 changes in response to an antibody to vascular endothelial growth factor (B20.4.1.1) and a selective dual phosphoinositide 3-kinase/mammalian target of rapamycin inhibitor (GDC-0980). GDC-0980 reduced viable tumor pO2 during a 3-day treatment period, and a significant reduction was also produced by B20.4.1.1. Overall, this method provides an unprecedented view of viable tumor pO2 and contributes to a greater understanding of the effects of antivascular therapies on the tumor's microenvironment

Real-Time CARS Imaging Reveals a Calpain-Dependent Pathway for Paranodal Myelin Retraction during High-Frequency Stimulation

High-frequency electrical stimulation is becoming a promising therapy for neurological disorders, however the response of the central nervous system to stimulation remains poorly understood. The current work investigates the response of myelin to electrical stimulation by laser-scanning coherent anti-Stokes Raman scattering (CARS) imaging of myelin in live spinal tissues in real time. Paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation. Retraction was seen to begin minutes after the onset of stimulation and continue for up to 10 min after stimulation was ceased, but was found to reverse after a 2 h recovery period. The myelin retraction resulted in exposure of Kv 1.2 potassium channels visualized by immunofluorescence. Accordingly, treating the stimulated tissue with a potassium channel blocker, 4-aminopyridine, led to the appearance of a shoulder peak in the compound action potential curve. Label-free CARS imaging of myelin coupled with multiphoton fluorescence imaging of immuno-labeled proteins at the nodes of Ranvier revealed that high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down

Nanomedicine and chemical imaging approaches to traumatic spinal cord injury

Traumatic spinal cord injury (SCI) results in immediate disruption of cell membranes in affected neural and endothelial tissues, followed by extensive secondary neurodegenerative processes. Due to the complication of the neurodegenerative processes, currently there is no golden therapy for SCI. The major part of the thesis is developing a nanomedicine approach targeting the damaged membranes at the early stage of SCI (Nature Nanotechnology, 2010, 5, 80-87). Here we show that axonal membranes injured by compression can be effectively repaired by using self-assembled monomethoxy poly(ethylene glycol)-poly(D,L-lactic acid) di-block copolymer micelles (60 nm diameter). Injured spinal tissue incubated with micelles showed rapid restoration of compound action potential and reduced calcium influx into axons. Intravenously injected micelles effectively recovered the locomotor function. The micelles showed no adverse effects after systemic administration to live rats. A second part of my thesis work focused on nonlinear optical images to study tissue pathophysiology following SCI. By integration of different imaging modalities such as two-photon excited fluorescence, sum frequency generation, and coherent anti-Stokes Raman scattering (CARS) on the sample platform, we investigated acrolein induced demyelination through nodes of Ranvier. By employing inherent CARS signal from myelin sheath and strategies to minimize surgery, motion distortion and scar formation, we demonstrated high resolution in vivo imaging of normal and injured spinal cord in live rats. Our longitudinal visualization of de- and re-myelination at signle axon level provides a novel platform for rational design of therapies aimed at promoting myelin plasticity and repair. In addition, desorption electrospray ionization (DESI) mass spectrometry was introduced as a complementary method for label-free analysis of lipid oxidation in SCI rats