Mesoscopic packing of disk-like building blocks in calcium silicate hydrate

At 100-nanometer length scale, the mesoscopic structure of calcium silicate hydrate (C-S-H) plays a critical role in determining the macroscopic material properties, such as porosity. In order to explore the mesoscopic structure of C-S-H, we employ two effective techniques, nanoindentation test and molecular dynamics simulation. Grid nanoindentation tests find different porosity of C-S-H in cement paste specimens prepared at varied water-to-cement (w/c) ratios. The w/c-ratio-induced porosity difference can be ascribed to the aspect ratio (diameter-to-thickness ratio) of disk-like C-S-H building blocks. The molecular dynamics simulation, with a mesoscopic C-S-H model, reveals 3 typical packing patterns and relates the packing density to the aspect ratio. Illustrated with disk-like C-S-H building blocks, this study provides a description of C-S-H structures in complement to spherical-particle C-S-H models at the sub-micron scale.Croucher Foundation (Start-up Allowance for Croucher Scholars with the Grant No. 9500012)Research Grants Council (Hong Kong, China) (through the Early Career Scheme (ECS) with the Grant No. 139113

Harnessing multi-domain knowledge for user-centric product conceptual design

Conceptual design is the design phase that deploys product functions and structures based on user requirements and ultimately generates conceptual design solutions. The increasing diversification of products has led to the promotion of customized design that involves deep user participation. As a result, there has been a growing focus on user-centric conceptual design. In this regard, the relationship among users, designers, and design solutions has been changed, which has brought challenges to the traditional designer-oriented design model. To address the complex understanding and decision-making problem caused by deeper user participation, emerging new user-centric product conceptual design model needs to be discussed. In the new design model, addressing the changing or growing requirements of users through the design of solutions and leveraging multi-domain knowledge to guide the conceptual design process are the critical areas of focus. To further describe this design model, this paper examines the user-centric interconnection among users, designers, design solutions, and multi-domain knowledge. In order to optimize design solutions, the solution resolution process and knowledge mapping based on design deviations are considered effective approaches. In addition, the paper also presents the types of design deviations and the multi-domain knowledge support techniques

First Place Solution to the CVPR'2023 AQTC Challenge: A Function-Interaction Centric Approach with Spatiotemporal Visual-Language Alignment

Affordance-Centric Question-driven Task Completion (AQTC) has been proposed to acquire knowledge from videos to furnish users with comprehensive and systematic instructions. However, existing methods have hitherto neglected the necessity of aligning spatiotemporal visual and linguistic signals, as well as the crucial interactional information between humans and objects. To tackle these limitations, we propose to combine large-scale pre-trained vision-language and video-language models, which serve to contribute stable and reliable multimodal data and facilitate effective spatiotemporal visual-textual alignment. Additionally, a novel hand-object-interaction (HOI) aggregation module is proposed which aids in capturing human-object interaction information, thereby further augmenting the capacity to understand the presented scenario. Our method achieved first place in the CVPR'2023 AQTC Challenge, with a Recall@1 score of 78.7\%. The code is available at https://github.com/tomchen-ctj/CVPR23-LOVEU-AQTC.Comment: Winner of CVPR2023 Long-form Video Understanding and Generation Challenge (Track 3

Co-infusion of haplo-identical CD19-chimeric antigen receptor T cells and stem cells achieved full donor engraftment in refractory acute lymphoblastic leukemia

Abstract Background Elderly patients with relapsed and refractory acute lymphoblastic leukemia (ALL) have poor prognosis. Autologous CD19 chimeric antigen receptor-modified T (CAR-T) cells have potentials to cure patients with B cell ALL; however, safety and efficacy of allogeneic CD19 CAR-T cells are still undetermined. Case presentation We treated a 71-year-old female with relapsed and refractory ALL who received co-infusion of haplo-identical donor-derived CD19-directed CAR-T cells and mobilized peripheral blood stem cells (PBSC) following induction chemotherapy. Undetectable minimal residual disease by flow cytometry was achieved, and full donor cell engraftment was established. The transient release of cytokines and mild fever were detected. Significantly elevated serum lactate dehydrogenase, alanine transaminase, bilirubin and glutamic-oxalacetic transaminase were observed from days 14 to 18, all of which were reversible after immunosuppressive therapy. Conclusions Our preliminary results suggest that co-infusion of haplo-identical donor-derived CAR-T cells and mobilized PBSCs may induce full donor engraftment in relapsed and refractory ALL including elderly patients, but complications related to donor cell infusions should still be cautioned. Trial registration Allogeneic CART-19 for Elderly Relapsed/Refractory CD19+ ALL. NCT0279955

Molecular dynamics study on stiffness and ductility in chitin–protein composite

Chitin–protein composite is the structural material of many marine animals including lobster, squid, and sponge. The relationship between mechanical performance and hierarchical nanostructure in those composites attracts extensive research interests. In order to study the molecular mechanism behind, we construct atomistic models of chitin–protein composite and conduct computational tensile tests through molecular dynamics simulations. The effects of water content and chitin fiber length on the stiffness are examined. The result reveals the detrimental effect on the stiffness of chitin–protein composite due to the presence of water molecules. Meanwhile, it is found that the chitin–protein composite becomes stiffer as the embedded chitin fiber is longer. As the tensile deformation proceeds, the stress–strain curve features a saw-tooth appearance, which can be explained by the interlocked zigzag nanostructure between adjacent chitin fibers. These interlocked sites can sacrificially break for energy dissipation when the system undergoes large deformation, leading to an improvement of ductility.Croucher Foundation (Start-up Allowance for Croucher Scholars Grant No. 9500012)Research Grants Council (Hong Kong, China) (Early Career Scheme Grant No. 139113

Development of a coarse-grained α-chitin model on the basis of MARTINI forcefield

At nanoscale, atomistic simulation is widely used for investigating crystalline chitin fibers, the structural component for many biological materials. However, the longitudinal dimension of naturally occurring chitin fibers exceeds hundreds of nanometer, beyond the investigation range of all-atom simulation due to the limitation of computational power. Under this context, coarse-grained simulation is a useful alternative that facilitates the investigation of a large system. We develop a coarse-grained model for describing the structural and mechanical properties of α-chitin. The developed coarse-grained model can reasonably predict these properties. Moreover, this model is consistent with existing coarse-grained force fields for proteins. The present model of α-chitin possesses good potential and applicability in the investigation of natural chitin-based materials at the length scale of several hundred nanometers.Research Grants Council (Hong Kong, China) (Early Career Scheme, Grant No. 139113)Croucher Foundation (Start-up Allowance for Croucher Scholars, Grant No. 9500012

Effect of Acetyl Group on Mechanical Properties of Chitin/Chitosan Nanocrystal: A Molecular Dynamics Study

Chitin fiber is the load-bearing component in natural chitin-based materials. In these materials, chitin is always partially deacetylated to different levels, leading to diverse material properties. In order to understand how the acetyl group enhances the fracture resistance capability of chitin fiber, we constructed atomistic models of chitin with varied acetylation degree and analyzed the hydrogen bonding pattern, fracture, and stress-strain behavior of these models. We notice that the acetyl group can contribute to the formation of hydrogen bonds that can stabilize the crystalline structure. In addition, it is found that the specimen with a higher acetylation degree presents a greater resistance against fracture. This study describes the role of the functional group, acetyl groups, in crystalline chitin. Such information could provide preliminary understanding of nanomaterials when similar functional groups are encountered

A Non-Destructive Method for Hardware Trojan Detection Based on Radio Frequency Fingerprinting

Hardware Trojans (HTs) pose a security threat to the Internet of Things (IoT). Attackers can take control of devices in IoT through HTs, which seriously jeopardize the security of many systems in transportation, finance, healthcare, etc. Since subtle differences in the circuit are reflected in far-field signals emitted by the system, the detection of HT status can be performed by monitoring the radio frequency fingerprinting (RFF) of the transmitting signals. For the detection of HTs, a non-destructive detection method based on RFF is proposed in this paper. Based on the proposed method, the detection of HTs can be achieved without integrating additional devices in the receiver, which reduces associated costs and energy consumption. QPSK and triangular-wave signals are measured and identified via experimentation, and the results validate the proposed method. For identifying the presence and operating state of Trojan, the average accuracy achieved measures as high as 98.7%. Notably, with regard to capturing the moment of Trojan activation in the AES encryption circuit, the accuracy of the proposed method is 100% and can provide warning of the threat in a timely manner

Photothermal catalytic H2 production over hierarchical porous CaTiO3 with plasmonic gold nanoparticles

The synergistic promotion by photocatalysis and thermocatalysis is a promising approach for sustainable hydrogen (H2) production. Herein, we rationally design a perovskite-based catalyst with three-dimensionally ordered macroporous structure (3DOM CaTiO3-Au) for photothermal catalytic H2 production from different substrates. The hierarchical 3DOM structure facilitates light harvesting and mass diffusion of the substrates, while the gold nanoparticles (Au NPs) promote charge separation. The photogenerated and hot electrons are oriented accumulated on the surface of Au NPs. The non-metallic gold species [Au(I)] show more activity for H2 evolution. As a result, 3DOM CaTiO3-Au exhibits excellent activity for H2 production from glycerol and other substrates with hydroxyl groups. The present work demonstrates a feasible approach to improve sustainable H2 production by rationally designing and fabricating efficient photothermal catalysts