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Energy absorption of a bio-inspired cylindrical sandwich structure
No full textThis research investigates the energy absorption capability of a new bio-inspired cylindrical sandwich structure (BCSS). The sandwich core of the BCSS is designed to mimic the skeletal system of deep-sea glass sponge, which has a square lattice architecture reinforced by diagonal bracings. In this study, energy absorption characteristics are numerically evaluated, with results compared to those of conventional cylindrical sandwich structures with typical lattice and foam cores. It is found that the BCSS has significantly higher energy absorption capacity. In detail, the specific energy absorption of the BCSS is 31.2 %, 18.1 % and 24.4 % higher than those of conventional cylindrical sandwich structures with the kagome, square and foam cores, respectively. Furthermore, a parametric study is performed which reveals that the cell number and the wall thickness of both the core and the skins are key factors determining the energy absorption capacity of the BCSS. Finally, a theoretical derivation is developed to conveniently predict the mean crushing force of the BCSS. This research sheds light on using biomimetic approaches to design an advanced composite structure with high energy absorption efficiency
Translocation of Pyrimidine Derivative-Capped Gold Nanoparticles via Membrane Ion Channels Induce Pseudomonas aeruginosa and Staphylococcus aureus Cell Death
No full textAntibiotic resistance is a serious global health concern. Here, we designed a novel class of bactericidal nanoparticles, pyrimidine derivative-capped gold nanoparticles (MP-AuNPs) with 12 nm, exhibiting prominent antibacterial activity against Pseudomonas aeruginosa 4-log reduction and a 2-log reduction against Staphylococcus aureus cells within 1 h. We demonstrated that MP-AuNPs appeared to be transported across the bacterial cell wall in an energy-dependent way via potassium ion (K+) channels, thus affecting the transmembrane proteins and ultimately causing depolarization of the cell membrane and destruction of the cell envelope, leading to cell death. Internalized MP-AuNPs not cause significant DNA fragmentation or a measurable imbalance in the cell’s redox state. In this case, the membrane damage was not caused by intracellular lipid peroxidation MP-AuNPs and exhibited good biocompatibility to mammalian cells. These findings reveal a previously unknown bactericidal mechanism associated with MP-AuNPs and provide a potential avenue for developing new antibacterial therapies
Optimized octree codec for geometry-based point cloud compression
No full textGeometry-based point cloud compression (G-PCC) standard is devoted to generic point clouds and offers excellent performance. However, redundancies are found in the original octree codec of G-PCC. This paper addresses the found issues to optimize the octree codec of G-PCC to be more precise. First, uniform contexts are proposed based on the neighbouring child nodes and nodes for the bitwise mode. Second, we merge the single-child mode into the planar mode. A method of eligibility determination for this new planar mode guided by the required number of coded bits is proposed. In addition, the characteristics of each plane in the point cloud are utilized to design contexts for the new planar mode. Third, we use the exponential moving average to optimize the contexts for the bitwise and planar modes, guaranteeing low memory consumption and high compression performance. Experimental evaluation, performed on a diversity of point clouds in the common test condition of G-PCC, demonstrates that the proposed methods enhance the compression performance of the octree codec in G-PCC with a gain of − 2.5 and − 5.8% for lossless and lossy geometry compression, respectively. At the same time, the computational complexity is reduced. Part of this work has been adopted to the latest G-PCC Edition 2. Compared to methods published in recent years, the improved octree codec of G-PCC also shows the advantages of compressing a diversity of point clouds
GPU-DEM-based heat transfer model for an HTGR pebble bed
No full textBased on the discrete element method (DEM) and GPU parallel computing, a particle heat transfer model is developed to simulate the heat transfer in a pebble bed of the high-temperature gas-cooled reactor (HTGR). The model is implemented based on a previously developed GPU-DEM program by our team and uses the mesh-based neighbor searching algorithm for the heat transfer calculation. This model couples the conduction and radiative heat transfer between the pebbles and incorporates neural networks and empirical fittings to calculate the radiation view factors, which can improve computational efficiency. The effective thermal conductivity of different models and experimental data are used to verify the accuracy of the model, and the influence of different radiation heat transfer models on the results is also compared. The results show that the effective thermal conductivity derived from the current model is comparable to the classical models at different temperatures, and the numerical simulation results based on the current model are in good agreement with the corresponding experimental data. Additionally, the model achieves a single-core speedup ratio of 126–395 times with GPU acceleration, significantly enhancing computational efficiency. In conclusion, the current model has been effectively verified for accuracy and computational efficiency, and it demonstrates great potential in dealing with large-scale pebble flow and heat transfer challenges in HTGRs
“The beginning was traumatising” – Industry 4.0: A lifesaver or disruptor? A knowledge-based viewpoint
No full textRecent research recognises the importance of Industry 4.0 (I4.0) for government, industry, and education stakeholders. Nevertheless, there are calls for alternative ways of deepening knowledge, including adopting cross-nation and qualitative perspectives. In responding to these calls and considering the knowledge-based view of the firm, this study investigates company leaders’ perceptions concerning I4.0 preparedness among their employees, employees’ reactions to the new I4.0 regime, and how companies manage the process of knowledge acquisition to adopt I4.0. Data from 80 semi-structured, open-ended interviews were gathered from companies operating in Bolivia and Vietnam. The analysis uncovered the importance of company- and self-driven knowledge acquisition concerning employees’ I4.0 preparedness. The I4.0-motivated, I4.0-alienated, and uncertain future dimensions best illustrated staff’s reactions, while I4.0 change agents, technology-based conditions, and being non-risk adverse were best exemplars of company’s management of I4.0. The study discusses key practical and theoretical implications and proposes a theoretical framework
Ripple effect of disruptions on performance in supply chains: an empirical study
No full textPurpose
The present study is performed to identify the propagation mechanism of the ripple effect as well as examine the simultaneous impact of risks on supply chain (SC) performance.
Design/methodology/approach
A theoretical framework with many hypotheses regarding the relationships between SC risk types and performance is established. The data are collected from a large-scale survey supported by a project of the Japanese government to promote sustainable socioeconomic development for the Association of Southeast Asian Nations (ASEAN) region, with the participation of 207 firms. Structural equation modeling (SEM) is used to test the hypotheses of the theoretical framework.
Findings
It is indicated that human-made risk causes operational risk, while natural risk causes both supply risk and operational risk. Furthermore, the impacts of human-made risk and natural risk on performance are amplified through operational risk.
Research limitations/implications
This study is one of the first attempts that identifies the propagation mechanism of the ripple effect and examines the simultaneous impact of risks on performance in construction SCs.
Originality/value
Although many studies on risk management in construction SCs have been carried out, they mainly focus on risk identification or quantification of risk impact. It is observed that research on the ripple effect of disruptions has been very scarce
A multi-country study of image-based sexual abuse: extent, relational nature and correlates of victimisation experiences
No full textThis study examined image-based sexual abuse (IBSA) victimisation in the United Kingdom, Australia, and New Zealand (n = 6,109). Findings showed that 37.7% (n = 2,306) of respondents had at least one IBSA victimisation experience since 16 years of age. Logistic regression analyses further identified that demographic characteristics (age, sexuality, disability/assistance), attitudes towards IBSA, and experiential variables (online dating and sexual self-image behaviours, IBSA perpetration) were each predictors of IBSA victimisation. Though gender did not predict the overall extent of IBSA victimisation, the relational contexts and impacts of IBSA remained gendered in particular ways. Implications of the study are discussed with respect to conceptualising gendered violence and future research
Entrepreneurial leadership fostering service innovation in the hospitality firms: the roles of knowledge acquisition, market-sensing capability and competitive intensity
No full textPurpose: This study aims to investigate the effects of entrepreneurial leadership on service innovation in the hospitality industry and examine the mediating effects of market-sensing capability and knowledge acquisition. Additionally, the study explores the moderating role of competitive intensity in the relationships between market-sensing capability, knowledge acquisition and service innovation, drawing on the dynamic capability theory and resource dependence theory. Design/methodology/approach: The data for this study were obtained from 322 employees and 137 leaders working in 103 hotels in Vietnam, using a time-lagged approach. The collected data were analyzed using structural equation modeling in SPSS Amos 28. Findings: The results of this study reveal a significant positive association between entrepreneurial leadership and service innovation, with mediation effects observed through both knowledge acquisition and market-sensing capability. Moreover, the findings demonstrate that competitive intensity moderates the association between knowledge acquisition and service innovation. Practical implications: The results of this study provide implications for hospitality firms to cultivate entrepreneurial leadership through leadership training and development programs and enhance their dynamic capabilities (i.e. market-sensing capability and knowledge acquisition) to allow them to survive and develop in a competitive market. Originality/value: This study advances entrepreneurial leadership research in the hospitality context by identifying mediating and moderating mechanisms that translate entrepreneurial leadership into hospitality firms’ service innovation
Alleviation of Diabetic Retinopathy by Glucose-Triggered Delivery of Vitamin D via Dextran-Gated Functionalized Mesoporous Silica Nanoparticles
No full textDiabetic retinopathy (DR) is the most common retinal disorder, developed in 35% of patients with diabetes mellitus. Lower serum levels of 25-hydroxyvitamin D are associated with the increased risk of developing DR. High doses of the active form of vitamin D (VD), on the contrary, for a long period of time may lead to hypercalcemia and an imbalance in the regulation of bone metabolism. Herein, we studied the efficacy of dextran-gated carboxyphenylboronic acid (CPBA)-functionalized mesoporous silica nanoparticles (MSNs) for glucose-sensitive delivery of 1,25-dihydroxyvitamin D3 to modulate cellular oxidative stress and inflammation for managing DR. The physical adsorption technique was employed to load VD onto nanoparticles (263.63 μg/mg (w/w)). In the presence of glucose, the dextran molecules detach from pores, allowing VD to release since glucose has 1,2-cis diol groups which have very high affinity to CPBA. Approximately 75% of VD was released upon exposure to 25 mM glucose at a time point of 10 h, demonstrating glucose-responsive delivery. Furthermore, MSN-CPBA was able to deliver VD in a glucose-dependent manner and improve the bioavailability of VD. In high-glucose-supplemented human retinal cells, MSN-CPBA increased the bioavailability of VD and reduced cellular oxidative stress and inflammation. The results suggested that the VD-loaded nanocarrier exerted remarkable therapeutic capacity in reducing the risk of developing DR. By using MSN-CPBA as a delivery platform with dextran gating, the research proposes an effective treatment approach for improving the bioavailability and effectiveness of a hydrophobic molecule in the treatment of DR
The changing narrative of early childhood intervention in Australia: Service providers’ perspectives on the implementation of the National Disability Insurance Scheme
No full textThe Australian National Disability Insurance Scheme (NDIS) completed its roll-out in 2020 with the objective of addressing the inadequacies of a fragmented and underfunded service system for people with disabilities. Under the scheme, young children with disabilities or developmental delay can now access services through the Early Childhood Approach, which is delivered by a range of not-for profit and for-profit organizations. Considering the significance of the resulting service system changes and the critical role of service providers, the aim of the present study was to examine their experiences in the State of Victoria. Forty-five service providers participated in interviews and focus groups which generated information grouped into four themes: (1) A changed orientation; (2) Early childhood intervention (ECI) practice; (3) ECI workforce; (4) The potential for a new system. Participating service providers reported several challenges in their quest to effectively support children and their families. It is concluded that for the NDIS to fulfil its promise and potential, revisions and adaptations of its systems and policies that incorporate the current ECI evidence-based knowledge and translation into real-world implementation are required