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Insights into the usage of biobased organic acids for treating municipal solid waste incineration bottom ash towards metal removal and material recycling
No full textThe recycling of incineration bottom ash (IBA) is crucial for sustainable municipal solid waste (MSW) management and alleviating landfill burdens. However, limited environmentally friendly methods exist to effectively treat IBA for safe recycling. This study systematically examined the performance of biobased organic acids, namely citric acid (CA), oxalic acid (OA), lactic acid (LA), and levulinic acid (LEA), for IBA treatment. CA shows high extraction efficiency for most trace metals (e.g., Mn > 65 %, Pb > 50 %, Co approx.100 %, Cd > 85 %, Zn > 80 %, Ni > 80 %), while OA performs better for certain trace metals (e.g., Sn approx.99 %, Sb > 70 %, Mo > 70 %, Cr > 50 %). Multivariate statistical analysis and instrumental techniques were used to gain deeper insights into the critical mechanisms, including proton promoted dissolution, ligand related dissolution and precipitation/co-precipitation. The latter two mechanisms are distinctive metal extraction behaviours by organic acids compared to their inorganic counterparts. Both CA- and OA-treated alkaline-washed IBA residues demonstrate high leaching reduction efficiency (>99.9 %) of the critical heavy metals, making the treated IBA residues suitable for safe recycling as construction materials. This study highlights the potential of environmentally friendly organic acids which can be derived from bio-wastes for treating and repurposing IBA as resources for construction materials, promoting sustainable waste management for MSW incineration ash.Ministry of Education (MOE)This research was supported by the Ministry of Education, Singapore, under the Academic Research Fund Tier 1 (RG84/19)
Trump's Gaza plan: a dangerous provocation
No full textDonald Trump’s proposal to turn Gaza into a new “Riviera of the Middle East” by forcibly displacing indigenous Palestinians violates international law and mirrors failed Western tactics. The enduring trauma of the 1948 Nakba (Arabic for “catastrophe”) when the State of Israel was proclaimed by David Ben-Gurion, remains undiminished. The current ceasefire must lead to recognition and implementation of practical and realistic measures to achieve justice for Palestinians.Published versio
Three essays on innovation catch-up in emerging markets
No full textThis thesis examines the complex process of innovation catch-up in emerging market firms (EMFs) from multiple perspectives. Through three interconnected chapters, the research explores the theoretical foundations and empirical evidence related to EMFs’ innovation catch-up, focusing on its two dimensions: the influence of managerial teams and the impact on firm-level capabilities and value.
The first chapter lays the foundation by systematically reviewing the literature on innovation catch-up, proposing a comprehensive framework and identifying key research gaps. I raise questions: What aspects do lagging EMFs catch up in, and who are the key actors involved in different catch-up processes? When do lagging EMFs choose to promote catch-up? How can firms achieve catch-up in emerging markets (EMs)? This paper reviews innovation catch-up research published in top-tier journals over 27 years, from 1997 to 2023.
The second chapter explores the antecedent of innovation catch-up by empirically investigating the strategies that lagging EMFs employ, particularly focusing on the roles of executive returnees. I test two dimensions of catch-up - innovation output and the transfer of research-oriented knowledge that quantifies the firm-level efficiency of applying frontier research-oriented knowledge to innovation outcomes. The theoretical framework suggests that
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returnees in top management teams (TMTs) who take a hands-on approach to innovation activities contribute to lagging EMFs’ catch-up with global leaders in transferring research- oriented knowledge, not innovation output. We further posit that laggards with executive returnees taking a hands-on approach to innovation achieve a more significant catch-up in the transfer of research-oriented knowledge than laggards with a higher number of executive returnees. Using a sample of Chinese-listed and US-listed firms in the pharmaceutical and biotechnological sectors between 2013 and 2019 and applying content analysis through firm- level patent and top-tier publication data, I find support for the hypotheses. Overall, the paper reveals the importance of TMTs' characteristics and daily innovation involvement in achieving significant catch-up in two dimensions in EMs.
The third chapter extends the analysis to the economic implications of innovation catch-up, specifically examining how lagging EMFs’ catch-up in two dimensions influences firm market value. Based on the data from Chinese-listed and US-listed pharmaceutical and biotechnological firms, the findings show that catch-up in the transfer of research-oriented knowledge is positively associated with the market value of lagging EMFs, measured by Tobin’s q. The empirical result also indicates that this positive association is stronger for POEs than SOEs in EMs. The paper sheds light on the economic impact of lagging EMFs’ innovation catch-up for research and practice.Doctor of Philosoph
Phase separation of MYB73 regulates seed oil biosynthesis in Arabidopsis
No full textMYB family transcription factors (TFs) play crucial roles in plant development, metabolism, and responses to various stresses. However, whether MYB TFs are involved in regulating fatty acid biosynthesis in seeds remains largely elusive. Here, we demonstrated that transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing MYB73 exhibit altered FATTY ACID ELONGATION1 (FAE1) expression, seed oil content, and seed fatty acid composition. Electrophoretic mobility shift assays showed that FAE1 is a direct target of MYB73, and functional assays revealed that MYB73 represses FAE1 promoter activity. Transcriptomic analysis of the MYB73-overexpressing plants detected significant changes in the expression of genes involved in fatty acid biosynthesis and triacylglycerol assembly. Furthermore, MYB73 expression was responsive to abscisic acid (ABA), and ABA-responsive element binding factor 2 directly bound to the ABA-responsive element in the MYB73 promoter to activate its expression. Additionally, we determined that MYB73 exhibits the hallmarks of an intrinsically disordered protein and forms phase-separated condensates with liquid-like characteristics, which are important in regulating target gene expression. Together, our findings suggest that MYB73 condensate formation likely fine-tunes seed oil biosynthesis.Ministry of Education (MOE)National Research Foundation (NRF)Published versionThis work was supported by Ministry of Education (MOE) of Singapore Tier 2 (grant nos. MOE-T2EP30220-0011 and MOE-T2EP30123-0001 to W.M.), MOE of Singapore Tier 1 (grant no. RG32/23 to W.M.), MOE of Singapore Tier 2 (grant no. MOE-T2EP30122-0021 to Y.M.), MOE of Singapore Tier 3 (MOE2019-T3-1-012 to Y.M.), Singapore National Research Foundation Investigatorship (grant no. NRF-NRFI08-2022-0012 to Y.M.), and MOE of Singapore Tier 2 (grant no. MOE- T2EP30122-0017 to M.M.)
Ni-MOF engineered system targeting macrophage aurora A kinase for bone loss prevention through PD-L1 activation
No full textPostmenopausal bone loss due to estrogen deficiency necessitates effective therapeutic strategies. Our study explores targeting macrophage Aurora A kinase to mitigate bone loss. Aurora A kinase phosphorylation is observed being increased in bone marrow-derived macrophages (BMDMs) from ovariectomy (OVX) mice, along with a reduction in programmed death-ligand 1 (PD-L1) expression. Detailed analysis reveals that PD-L1 plays an immunomodulatory role by lowering the ratio of T helper 17 cells and regulatory T cells. The metabolic shift toward glycolysis through transcriptome sequencing, induced by Aurora A kinase inhibition, is essential for PD-L1 expression in BMDMs. The interaction between Aurora A kinase and cytochrome C oxidase subunit 5B is found to enhance PD-L1 expression. To apply these findings therapeutically, a multifunctional system is developed using a Nickel-metal organic framework combined with bisphosphonate and MLN8237 (BP@Ni-MOF/MLN8237). This system targets bone tissues through bisphosphonate and effectively delivers MLN8237 to macrophages, promoting PD-L1 expression for a favorable immune environment. Moreover, this system exhibits an obvious angiogenic effect. The present study highlights the crucial roles of macrophage Aurora A kinase and PD-L1 in maintaining bone homeostasis as well as the angiogenesis effect by Ni-MOF engineered system, presenting a promising therapeutic approach to prevent postmenopausal bone loss.This work was supported by the National Science Foundation of China (82372406), the National Key Research & Development Program of China (2021YFA1101503), and the Wuhan Science and Technology Bureau (2022020801020464)
How do humans respond to large realized losses?
No full textIn a controlled field setting, in which the majority of people in our sample lose more than £90,000, we examine how human beings respond to major financial losses. University ethics boards would not allow this kind of huge-loss phenomenon to be studied with normal social-science experiments. Yet the scientific and practical issues at stake are unusually important ones. In the analyzed gameshow setting, individuals are handed £100,000 in cash. They then have to make risky decisions. Facing a sequence of seven questions, individuals are required to distribute their cash endowment over a set of possible answers. Participants lose any cash placed on a wrong answer. In a sample of British participants, we find that people become increasingly more cautious as they lose more of their cash endowment. A realized prior loss of £75,000 or more increases the propensity to fully diversify by 50 percentage points compared to a prior loss of £25,000. We find a similar cautious response in a smaller sample of US participants when the stakes are raised to $1 million US dollars. Our study appears to be the first to be able to calculate systematically how human beings react to large and unrecoverable financial losses.Published versio
Modeling and vulnerability analysis of UAV swarm based on two-layer multi-edge complex network
No full textSwarm systems of unmanned aerial vehicles (UAVs) have emerged as a popular subject of research on the Internet of Things owing to their higher flexibility, efficiency, and reliability than single UAVs. However, little research has been devoted to investigating the vulnerability of UAV swarms, and the traditional network model cannot fully and synchronously characterize their communication-based and mission-based relationships. This study proposes a two-layer multi-edge complex network model to characterize the UAV swarm by considering its status of communication and collaboration for the given mission. The model contains a communication layer and a function layer. In addition, we consider the area of coverage of the UAV swarm, provide the definitions and methods of calculation of three factors influencing its performance, and use them to develop a method to assess its performance for the three typical missions of attack, reconnaissance, and jamming. Furthermore, we propose a framework for the vulnerability analysis of the UAV swarm that can analyze its process of failure and measure its vulnerability. Finally, we use a swarm consisting of 10 UAVs as a case to verify the effectiveness and accuracy of the proposed model
A practical framework for robust lane detection and tracking in adverse weather
No full textRecently, autonomous driving systems are being progressively incorporated into vehicles. In the autonomous driving system, detecting lanes is a critical part that provides feedback on the vehicle’s position and enriches the path planning module with information on the road’s trajectory, high reliability and accuracy are required. Significant advancements in precision and effectiveness have been made through recent deep learning methods. However, lane detection in real-world scenarios still faces various challenges, including extreme lighting conditions, eroded lane markings, occlusions and adverse weather conditions, etc. Heavy rain as a representative of extreme weather conditions, can interfere with the sensory image signal by making it more challenging to detect the lanes. This can compromise the safety of the autonomous driving system. But due to the imbalanced popular datasets, many lane detectors are not evaluated adequately under rainy conditions, raising doubts about their robustness. Moreover, effectiveness has been a problem for many models. For the purpose of enhancing reliability and safety of the AV, lane detection need to perform in real-time to pass road information to other systems, enabling them to respond more readily to handle hazards or obstacles. This project proposed a lane detection and tracking framework combining the DL-based lane detector with a lane tracker. The lane tracking module was introduced as a post-processing method based on Kalman filtering, applied on the detection output of UFLD and can augment the output without touching the detection network. Additionally, to address the shortage of samples in adverse weather conditions, a synthetic rainy dataset named Tusimple-Rain was used as a supplementary dataset. Considering its superior data amount and diversity, after being projected to 2D and converted to TuSimple format, ONCE-3DLanes dataset was used for training and testing in our work as well. The lane detectors and the detection system developed by us were all pre-trained with TuSimple, TuSimple-Rain and ONCE-3DLanes, and were evaluated on the three datasets and various scene categories of ONCE-3DLanes. Results show that our approach outperformed the lane detector models without tracking on ONCE-3DLanes in terms of the accuracy, FP value and FN value under different weather conditions, showing its robustness. With frame skip set to five, the developed system also achieved an increased average FPS.Master's degre
Dual-plating aqueous Zn-iodine batteries enabled by halogen-complexation chemistry for large-scale energy storage
No full textAqueous Zn-I2 batteries are promising candidates for grid-scale energy storage due to their low cost, high voltage output and high safety. However, Ah-level Zn-I2 batteries have been rarely realized due to formidable issues including polyiodide shuttling and zinc dendrites. Here, we develop 10 Ah dual-plating Zn-I₂ batteries (DPZIB) by employing ZnIxG4(tetraglyme) complex chemistry, in which zinc and iodine are iteratively dissolved and deposited in the aqueous electrolyte. The battery contains no membrane or high-cost electrolytes. The G4 strengthens the Zn-I bond by acting as an electron donor, and meanwhile, it enhances the reductivity of electrolyte by its complexation with Zn2+. Such halogen-complexation chemistry endows static DPZIB with shuttle-free property, negligible self-discharge, and minimal zinc dendrites. The battery delivers a capacity of 301.5 mAh over 1800 h at 5 mA cm-2, a low capacity decay (0.028% drop per cycle for 800 cycles at 25 mA cm-2), and a scalable capacity of up to 10.8 Ah. As a proof of concept, we demonstrate an integrated system encompassing a membrane-free Zn-I2 flow battery to store solar electricity at daytime and power electronics at nights.Ministry of Education (MOE)National Research Foundation (NRF)Submitted/Accepted versionThe authors appreciate the financial support from the National Research Foundation, Singapore, under its Singapore–China Joint Flagship Project (Clean Energy) and the Singapore Ministry of Education, under its AcRF Tier 1 project (RT8/22). Joint Funds of the National Key Research and Development Program of China (2019YFA0705703), Shenzhen Science and Technology Program (KQTD20210811090112002), and the Overseas Research Co-operation Fund of Tsinghua Shenzhen International Graduate School. M.Y. Chuai thanks the financial support from Postdoctoral Fellowship Program (GZC20232668)
Phase-restoring subpixel image registration: enhancing motion detection performance in Fourier-domain optical coherence tomography
No full textPhase-sensitive Fourier-domain optical coherence tomography (FD-OCT) enables in-vivo, label-free imaging of cellular movements with detection sensitivity down to the nanometer scale, and it is widely employed in emerging functional imaging modalities, such as optoretinography (ORG), Doppler OCT, and optical coherence elastography. However, when imaging tissue dynamics in vivo, inter-frame displacement introduces decorrelation noise that compromises motion detection performance, particularly in terms of sensitivity and accuracy. Here, we demonstrate that the displacement-related decorrelation noise in FD-OCT can be accurately corrected by restoring the initial sampling points using our proposed Phase-Restoring Subpixel Image Registration (PRESIR) method. Derived from a general FD-OCT model, the PRESIR method enables translational shifting of complex-valued OCT images over arbitrary displacements with subpixel precision, while accurately restoring phase components. Unlike conventional approaches that shift OCT images either in the spatial domain at the pixel level or in the spatial frequency domain for subpixel correction, our method reconstructs OCT images by correcting axial displacement in the spectral domain (k domain) and lateral displacement in the spatial frequency domain. We validated the PRESIR method through simulations, phantom experiments, and in-vivo ORG in both rodents and human subjects. Our approach significantly reduced decorrelation noise during the imaging of moving samples, achieving phase sensitivity close to the fundamental limit determined by the signal-to-noise ratio.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)Nanyang Technological UniversityNational Medical Research Council (NMRC)National Research Foundation (NRF)Published versionTong Ling acknowledges the support of the National Research Foundation, Singapore for the NRF Fellowship Award (NRFNRFF14-2022-0005), the Startup Grant (SUG) from Nanyang Technological University, the seed funding programme under NMRC Centre Grant—Singapore Imaging Eye Network (SIENA) (NMRC/CG/C010A/2017), and the Ministry of Education, Singapore under its AcRF Tier 1 Grant (RS19/20; RG28/21). Leopold Schmetterer acknowledges the funding support for the National Medical Research Council (CG/C010A/2017_SERI; OFLCG/004c/2018-00; MOH000249-00; MOH-000647-00; MOH-001001-00; MOH001015-00; MOH-000500-00; MOH-000707-00), National Research Foundation Singapore (NRF2019-THE002-0006; NRF-CRP24-2020-0001), A∗STAR (A20H4b0141), the Singapore Eye Research Institute & Nanyang Technological University (SERI-NTU Advanced Ocular Engineering (STANCE) Program), and the SERI-Lee Foundation (LF1019-1) Singapore. Veluchamy A. Barathi acknowledges the support for Singapore NMRC Centre Grant (NMRC/CG/M010/2017/Pre-Clinical). Ramkumar Sabesan and Vimal P. Pandiyan acknowledge the funding support for NIH/NEI Grants U01EY032055, R01EY029710; unrestricted Grant from Research to Prevent Blindness to UW Ophthalmology, Burroughs Wellcome Fund Careers at the Scientific Interfaces Award