Detection techniques for molecular interactions based on interferometry and micro-cantilever

Biosensors based on Atomic force microscope (AFM) cantilevers have recently been showing promising potential because of its portability and high sensitivity, the gold coated cantilever surface allows functionalization on the cantilever by immobilizing biomolecules like enzyme, DNA, RNA on the cantilever surface. Biomolecular reactions between the immobilized molecules and its target molecules on the cantilever can result in change in measurable mechanical signal like deflection, resonant frequency. Researchers can detect the presence and quantity of target molecules by measuring the deflections or resonant frequency change. This property of micro cantilever allows itself to have potential application in DNA/Protein detection. In addition, the gold surface of cantilever makes it possible to apply electrochemical technology in the biosensing system. We designed a mini optical system to monitor the deflection of cantilever when the DNA aptamer of Ebola virus glycoprotein (GP1,2) that is immobilized on the cantilever reacts with GP1,2 in the environment. The same experiment was conducted using Ebola secreted glycoprotein (sGP) and its DNA aptamer. The results show that the increase of GP1,2 concentration led to an increase in tensile surface stress, the tensile surface stress saturated at about 200nM of GP1,2. While the sGP results show that the increase of sGP concentration produced a compressive surface stress which saturates at 20nM. The linear range of experiment data has potential in the detection of Ebola virus at nanomolar concentration. We also set up a micro optical system of shoe box size to monitor the deflection of cantilever when the immobilized aptamers bind with target molecules in the environment. A verification with human alpha thrombin and its aptamer was conducted, which shows a promising potential of alpha thrombin detection. The portability of this new system allows a rapid detection at point-of-care. Other future work is planned in the last chapter, which includes a molecular dynamics simulation of stress induced by the binding between glycoprotein and its aptamer, and a novel electrochemical biosensor based on micro-cantilever

(E)-4-tert-Butyl-2-(2,6-diisopropyl­phenyl­imino­meth­yl)-6-(morpholinometh­yl)phenol

In the mol­ecule of the title compound, C28H40N2O2, the tert-butyl group is disordered over two positions; site-occupation factors were kept fixed at 0.5. The morpholine ring has a chair conformation. Intra­molecular O—H⋯N hydrogen bonding results in the formation of a planar six-membered ring, which is oriented at a dihedral angle of 0.70 (3)° with respect to the adjacent aromatic ring. The dihedral angle between the benzene rings is 67.66 (3)°

Edge data based trailer inception probabilistic matrix factorization for context-aware movie recommendation

The rapid growth of edge data generated by mobile devices and applications deployed at the edge of the network has exacerbated the problem of information overload. As an effective way to alleviate information overload, recommender system can improve the quality of various services by adding application data generated by users on edge devices, such as visual and textual information, on the basis of sparse rating data. The visual information in the movie trailer is a significant part of the movie recommender system. However, due to the complexity of visual information extraction, data sparsity cannot be remarkably alleviated by merely using the rough visual features to improve the rating prediction accuracy. Fortunately, the convolutional neural network can be used to extract the visual features precisely. Therefore, the end-to-end neural image caption (NIC) model can be utilized to obtain the textual information describing the visual features of movie trailers. This paper proposes a trailer inception probabilistic matrix factorization model called Ti-PMF, which combines NIC, recurrent convolutional neural network, and probabilistic matrix factorization models as the rating prediction model. We implement the proposed Ti-PMF model with extensive experiments on three real-world datasets to validate its effectiveness. The experimental results illustrate that the proposed Ti-PMF outperforms the existing ones. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature

Interpretable Motion Planner for Urban Driving via Hierarchical Imitation Learning

Learning-based approaches have achieved remarkable performance in the domain of autonomous driving. Leveraging the impressive ability of neural networks and large amounts of human driving data, complex patterns and rules of driving behavior can be encoded as a model to benefit the autonomous driving system. Besides, an increasing number of data-driven works have been studied in the decision-making and motion planning module. However, the reliability and the stability of the neural network is still full of uncertainty. In this paper, we introduce a hierarchical planning architecture including a high-level grid-based behavior planner and a low-level trajectory planner, which is highly interpretable and controllable. As the high-level planner is responsible for finding a consistent route, the low-level planner generates a feasible trajectory. We evaluate our method both in closed-loop simulation and real world driving, and demonstrate the neural network planner has outstanding performance in complex urban autonomous driving scenarios.Comment: 6 pages, 8 figures, accepted by IROS202

Clearing Persistent Extracellular Antigen of Hepatitis B Virus: An Immunomodulatory Strategy To Reverse Tolerance for an Effective Therapeutic Vaccination

Development of therapeutic vaccines/strategies to control chronic hepatitis B virus (HBV) infection (CHB) has been challenging due to HBV-induced tolerance. In this study, we explored strategies for breaking tolerance and restoring the immune response to the HBV surface antigen in tolerant mice. We demonstrated that immune tolerance status is attributed to the level and duration of circulating HBsAg in HBV carrier models. Removal of circulating HBsAg by a monoclonal anti-HBsAg antibody in tolerant mice could gradually reduce tolerance and reestablish B cell and CD4+ T cell responses to subsequent Engerix-B vaccination, producing protective IgG. Furthermore, HBsAg-specific CD8+ T cells induced by the addition of a TLR agonist, resulted in clearance of HBV in both serum and liver. Thus, generation of protective immunity can be achieved by clearing extracellular viral antigen with neutralizing antibodies followed by vaccination

Vaccines targeting preS1 domain overcome immune tolerance in hepatitis B virus carrier mice

Strong tolerance to hepatitis B virus (HBV) surface antigens limits the therapeutic effect of the conventional hepatitis B surface antigen (HBsAg) vaccination in both preclinical animal models and patients with chronic hepatitis B (CHB) infection. In contrast, we observed that clinical CHB patients presented less immune tolerance to the preS1 domain of HBV large surface antigen. To study whether targeting the weak tolerance of the preS1 region could improve therapy gain, we explored vaccination with the long peptide of preS1 domain for HBV virions clearance. Our study showed that this preS1-polypeptide rather than HBsAg vaccination induced robust immune responses in HBV carrier mice. The anti-preS1 rapidly cleared HBV virions in vivo and blocked HBV infection to hepatocytes in vitro. Intriguingly, vaccination of preS1-polypeptide even reduced the tolerized status of HBsAg, opening a therapeutic window for the host to respond to the HBsAg vaccine. A sequential administration of antigenically distinct preS1-polypeptide and HBsAg vaccines in HBV carrier mice could finally induce HBsAg/hepatitis B surface antibody serological conversion and clear chronic HBV infection in carrier mice. Conclusion: These results suggest that preS1 can function as a therapeutic vaccine for the control of CHB. (Hepatology 2017;66:1067-1082)

PSR J1926-0652: A Pulsar with Interesting Emission Properties Discovered at FAST

We describe PSR J1926-0652, a pulsar recently discovered with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using sensitive single-pulse detections from FAST and long-term timing observations from the Parkes 64-m radio telescope, we probed phenomena on both long and short time scales. The FAST observations covered a wide frequency range from 270 to 800 MHz, enabling individual pulses to be studied in detail. The pulsar exhibits at least four profile components, short-term nulling lasting from 4 to 450 pulses, complex subpulse drifting behaviours and intermittency on scales of tens of minutes. While the average band spacing P3 is relatively constant across different bursts and components, significant variations in the separation of adjacent bands are seen, especially near the beginning and end of a burst. Band shapes and slopes are quite variable, especially for the trailing components and for the shorter bursts. We show that for each burst the last detectable pulse prior to emission ceasing has different properties compared to other pulses. These complexities pose challenges for the classic carousel-type models.Comment: 13pages with 12 figure