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Atomically Dispersed Copper Electrocatalysts with Proton-feeding Centers for Efficient Ammonia Synthesis by Nitrate Electroreduction
No full textElectrocatalytic conversion of nitrate pollutants into ammonia (NH3) is promising for high-value chemical production while mitigating environmental pollution. Catalysts play a crucial role in facilitating the necessary chemical reactions, but despite substantial advancements, their efficiency and selectivity remain limited due to the high energy barriers associated with proton transfer. Herein, a unique electrocatalyst system is engineered with isolated copper sites embedded within nitrogen and oxygen co-doped porous carbon (CuSA-NO/C). This strategically designed electrocatalyst achieves an impressive NH3 Faradaic efficiency of 92.7% and a yield rate of 24.9 mg h−1 mgCu−1 at a low potential of −0.2 V vs RHE, outperformed most of all previously-reported atomically dispersed metal-nitrogen carbon (M-N-C) catalysts. The catalytically active site in this electrocatalyst is identified as Cu atom coordinated with two N atoms and two O atoms (CuN2O2). In situ infrared absorption spectroscopy and kinetics isotope experiments revealed that the intrinsic CuN2O2 dramatically enhances the water dissociation process and accelerates the protonation kinetics during nitrate reduction. Furthermore, the first principles calculations show that CuN2O2 catalytic sites also promote the adsorption of NO3− and desorption of NH3, along with the significantly facilitated water dissociation kinetics for proton feeding
Mathematical descriptions of grading linked with prediction of mechanical consequences of suffusion
No full textInternal erosion is a leading cause of disfunctions and failures of earth embankments when used as water retaining structures. Internal erosion results from water flowing through the embankments, removing particles from the soils forming the embankments. It may even occur in the embankment foundations if they are made of soils. It changes a soil's particle size distribution, increases its void ratio, shifts its critical state line upwards in the compression plane and alters its stress–strain behavior. This paper presents new mathematical links and constitutive model ingredients to capture these effects. They apply to a gap-graded soil and a particular type of erosion known as suffusion. The evolution of the particle size distribution is characterised through a grading state index, defined in terms of geometrical properties which are fractal. These new ingredients are incorporated into the Severn-Trent model to simulate stress–strain responses of the soil, subjected to drained triaxial compression, having experienced different amounts of suffusion. The simulations match the experimental data well. The model and its ingredients are also used to simulate other property changes to the gap-graded soil which follow different amounts of suffusion, especially the soil's reduced strength and increased tendency for compression
Quantifying the fatal and non-fatal burden of disease associated with child growth failure, 2000–2023: a systematic analysis from the Global Burden of Disease Study 2023
No full textBackground: Child growth failure (CGF), which includes underweight, wasting, and stunting, is among the factors most strongly associated with mortality and morbidity in children younger than 5 years worldwide. Poor height and bodyweight gain arise from a variety of biological and sociodemographic factors and are associated with increased vulnerability to infectious diseases. We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2023 to estimate CGF prevalence, the risk of infectious diseases associated with CGF, and the disease mortality, morbidity, and overall burden associated with CGF. Methods: In this analysis we estimated the all-cause and cause-specific (diarrhoea, lower respiratory tract infections, malaria, and measles) disability-adjusted life-years (DALYs) lost and mortality associated with stunting, wasting, underweight, and CGF in aggregate. We combined the burden associated with mild, moderate, and severe forms of CGF: stunting was defined as height-for-age Z scores (HAZ) less than –1, underweight was defined as weight-for-age Z scores (WAZ) less than –1, and wasting was defined as weight-for-height Z scores (WHZ) less than –1, according to WHO Child Growth Standards. Population-level continuous distributions of HAZ, WAZ, and WHZ were estimated for 2000 to 2023 using data from surveys, literature, and individual-level study data. The risk of incidence of, and mortality due to, diarrhoea, lower respiratory infections, malaria, and measles was separately estimated in a meta-regression framework from longitudinal cohort data for Z scores less than –1. Finally, fatal outcomes associated with these diseases were estimated with vital registration, verbal autopsy, and case-fatality data, while non-fatal outcomes were estimated with surveys as well as health-care utilisation and case reporting data. The exposure prevalence and relative risk estimates were from continuous distributions, allowing for direct assessment of the attributable fractions for mild, moderate, and severe stunting, underweight, wasting, and the combined impact of child growth failure within populations. All estimates were age-specific, sex-specific, geography-specific, and year-specific. Findings: We estimated that, in children younger than 5 years in 2023, CGF was associated with 79·4 million (95% uncertainty interval [UI] 47·0–106) DALYs lost and 880 000 (517 000–1 170 000) deaths. This represented 17·9% (10·6–23·8) of 444 million (434–457) total under-5 DALYs and 18·8% (11·1–25·0) of all 4·67 million (4·59–4·75) under-5 deaths. Compared to stunting (33·0 million [24·1–42·2] DALYs, 373 000 [272 000–477 000] deaths) and wasting (39·2 million [23·8–53·0] DALYs, 428 000 [256 000–583 000] deaths), childhood underweight was associated with the largest share of CGF-related disease burden: 52·2 million (21·9–75·1) DALYs and 573 000 (236 000–824 000) deaths in children younger than 5 years in 2023. Interpretation: CGF remains a leading factor associated with death and disability in children younger than 5 years, despite global attention and focused interventions to reduce the prevalence of associated CGF indicators. Our findings underscore the need for policies, strategies, and interventions that focus on all indicators of CGF to reduce its associated health burden. Funding: Gates Foundation
Intergenerational patterns of child protection system involvement in an Australian population cohort
No full textBackground: There is substantial diversity in patterns of intergenerational maltreatment within families. Objective: To characterise familial patterns of child protection contacts across generations among a representative population sample of Australian children. Participants and setting: Participants were 75,784 Australian children (followed from birth to age ~18 years) and their parents from the New South Wales Child Development Study. Methods: Child protection (CP) data (child: 2001–2021; parents: 1971–2021) were used to categorise family members into four subpopulations according to intergenerational patterns of contact with the CP system. Sociodemographic factors and CP system contacts were examined for all family members within intergenerational CP groups, using binary logistic regression. Results: Most families (67.8%) had no contact with child protection across generations. Approximately 31% of children were known to CP services, relative to 5% of mothers and 1.7% fathers in the cohort. The majority of children known to CP services (85%) had no parental history of maltreatment (‘cycle initiator’ families). Almost 79% of children whose parents had historical CP records were also known to CP services (‘cycle maintainers’; representing 15% of all children known to CP services) and 21% were unknown to child protection services (classed as ‘cycle breakers’; representing 4% of all children known to CP services). Parents classified as ‘cycle maintainers’ had more serious, frequent, and earlier involvement with the CP system, and higher levels of disadvantage, compared to other groups. Conclusions: Socioeconomic drivers of intergenerational CP system involvement deserve attention from policy makers
Understanding collective change attitudes: A diversity and faultline perspective
No full textAlthough implementing organizational change involves attitudinal support from both individuals and groups, researchers typically examine individual change attitudes as key drivers of change success. In this paper, we focus on collective change attitudes – defined as a group's overall evaluation of a proposed organizational change – to challenge and extend this developing construct. To do so, we adopt a diversity and faultline perspective to identify four distinct patterns of collective change attitudes: convergent, minority belief, fragmented, and bimodal patterns. We offer a theoretical model that explains the influence of group faultlines and change event characteristics on the emergence of the four patterns of collective change attitudes and their temporal trajectories over time. In addition, we theorize the influence of collective change attitudes on change implementation effectiveness. Our work offers implications for research and practice in organizational change and human resource management
Xuanxue’s 玄學 ongoing evolution: Thinking with Wang Bi’s name-actuality dialectic
No full textHow should we conceptualise a philosophical tradition retrospectively defined and continuously shaped by contemporary scholarship? This paper addresses this philosophy-of-historiography question by focusing on Xuanxue, a significant yet underdeveloped domain of Chinese philosophy centered on the corpus of the Wei-Jin (魏晉) Period (220–589 CE) and beyond. Scholarly conceptions of Xuanxue have long been bound by entrenched themes, the ‘Daoist’ label, and rigid periodisation. In contrast, this paper situates Xuanxue within both its historical milieu and the context of ongoing modern interpretations. Drawing heuristically from Wang Bi’s (王弼, 226–249 CE) conceptual interdependence between Name (ming 名) and Actual Situation (shi 實), I propose a new method (HPE) for evaluating Xuanxue conceptions with three criteria: Historical embeddedness, Plurality, and Evolvingness. This research thus offers a philosophically reflexive model for Xuanxue studies and the broader field of cross-cultural philosophy, demonstrating how ancient traditions can be engaged as dynamic intellectual projects
X-Ray Imaging of Fluid Flow and Reactive Transport in Dual-Porosity Media: Implications for Heap Leaching
No full textHeap leaching is a hydrometallurgical technique for extracting metals from low-grade ores and plays a vital role in supporting the global shift toward sustainable energy systems. While valued for its operational simplicity and cost-effectiveness, its efficiency is often limited by slow reaction rates and uneven fluid flow distribution. A key underexplored factor contributing to this inefficiency is the complex pore structures within the heap, particularly the influence of intra-particle porosity and fracture evolution on fluid transport and mineral dissolution processes.
This thesis explores flow and reactive transport through a series of controlled experiments that combine both engineered and natural porous systems. Engineered dual-porosity particles were designed to replicate critical features of chalcopyrite ores, such as micro-porosity and mineral content. Using advanced image processing and chemical analysis, the impact of intra-particle pore networks on fluid flow was studied. Complementary column leaching experiments on chalcopyrite particles further reveal that intra-pore variations through selective dissolution can affect lixiviant access.
To better understand transport dynamics, synchrotron-based imaging was employed to capture real-time changes in fluid distribution and dissolution processes. The resulting time-resolved dataset is processed to generate segmented 3D images distinguishing liquid, solid, and air phase, enabling visualisation of fluid behaviour influenced by intra- and inter-particle pore geometry across different column packings. This resource offers new insights into the links between flow patterns, pore network development, and mineral dissolution.
Overall, this thesis aims to deepen our understanding of how pore-scale structure and dynamic fluid behaviour influence leaching performance. The main novelty of this work lies in introducing a time-resolved, multi-scale experimental and micro-CT–driven framework to directly quantify how evolving intra-particle pore networks and transient fluid flow in dual-porosity systems govern leaching kinetics and mineral recovery. It highlights the importance of integrating high-resolution imaging with advanced image processing, and numerical modelling to capture the spatial and temporal complexity of reactive transport in porous media. The insights gained from this work contribute to a growing foundation for designing future experimental and modelling approaches to more accurately investigate and optimise heap leaching systems at larger scales
Autocatalytic Cas13a biosensor enabled by RNA-nanocircles for ultrasensitive RNA detection
No full textCas13a-based diagnostic systems have been widely utilized for the detection of RNA targets. However, without preamplification such systems are difficult to realize ultrasensitive (RT-PCR level) single pot RNA detection. Here, we found that double strand RNA can effectively activate the trans-cleavage activity of Cas13a RNP, while the cleavage rates of dsRNA by activated Cas13a RNP are very low. In addition, specially designed RNA-Nanocircle has limited ability to activate Cas13a RNP, but this activation is restored once the circular structures are cleaved and become linear. Based on this original method to control trans-cleavage activity of Cas13a RNP, we developed a Cas13a autocatalytic biosensing system assisted by RNA-Nanocircles, which allows one target RNA to activate numerous Cas13a RNPs. With this approach we show ultrasensitive detection of 1aM of synthetic RNA targets without preamplification within 15 min. The clinical utility of this biosensor was validated by monitoring miRNA-21 levels in plasma samples from colorectal cancer patients. This innovative approach highlights the potential of Cas13a-based biosensors in precision oncology, offering a rapid, non-invasive, and ultrasensitive method for RNA biomarker detection in liquid biopsies
Emergency department presentations, hospitalisations and police seizure data related to gamma-hydroxybutyrate (GHB) in New South Wales, Australia, from 2015 to 2024
No full textBackground and aims: Gamma-hydroxybutyrate (GHB) is an endogenous neurochemical and illicit synthetic drug. Its precursors, gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD), are often used as substitutes. We aimed to describe GHB-related harms in New South Wales (NSW), Australia. Design, setting and cases: Descriptive epidemiological study of data from three administrative datasets: emergency department (ED) presentations from 88 hospitals (1 July 2015 to 31 January 2024 – the latest available), admitted patient data from all NSW hospitals (1 July 2015 to 30 June 2023) and a subset of NSW Police Force seizure data. Note: analysis was not undertaken, data are presented descriptively. Measurements: ED presentations and hospitalisations were analysed for GHB-related presentations and admissions including severity of presentation, intubation and intensive care. NSW Police Force seizure data were examined for all analytically confirmed samples of GHB, GBL and 1,4-BD to assess trends over time. Findings: Over the study period, there were 9612 GHB-related ED presentations. Between July 2023 and January 2024, this was 101 per 100 000 unplanned presentations, relative to the previous full-year peak of 73.7 per 100 000 in 2022–2023 and the 2015–2016 rate of 24.9 per 100 000. The majority (56.1%) were assessed as Australian Triage Category 1 or 2, indicating the highest level of need. ED presentations in regional or remote areas accounted for 13.8% of all presentations in the most recent data, relative to 3.4% at the start of the study period. Hospitalisations totalled 6420 episodes, peaking at 19.6 per 100 000 population in 2020–2021. Nearly one in five patients required intubation, and a similar proportion required admission to intensive care. There was a trend of women accounting for a larger proportion of ED presentations and hospitalisations over time. GHB accounted for 0.1% of all police seizures analysed, and showed a shift from GBL to 1,4-BD dominance from 2022 onwards. Conclusions: Gamma-hydroxybutyrate-related emergency department presentations and hospitalisations in New South Wales, Australia, appear to have increased over the period from 2015 to 2024, which can support public health campaigns to reduce gamma-hydroxybutyrate-related harms
Multifunctional Carbon Nanotubes for Biosensing and Cancer Therapy
No full textWith the growing global burden of chronic diseases and cancer, there is an urgent need for precise diagnostic tools, real‑time cellular monitoring, and effective targeted therapies. Advanced nanomaterials provide promising solutions in biomedical engineering. Owing to their unique structure, electrical and catalytic properties, carbon nanotubes (CNTs) have been studied as multifunctional nanomaterials for both biosensing and therapeutic functions in this PhD project.
By tuning the length of vertically aligned carbon nanotubes (VACNTs) and transferring them onto a stretchable substrate, flexible and stretchable electrodes with high stretchability, durability, low detection limit, and high sensitivity were developed. These stretchable electrodes detected dopamine released from PC‑12 cells in real time under different temperatures and concentrations. VACNTs were also used to construct a single-cell H2O2 nanosensor. For the first time, H2O2 release from a single MCF‑7 cell was quantitatively monitored using this CNT‑based nanosensor. Furthermore, CNTs were used to synthesize targeted N‑defect nanotubes (FA‑RN‑CNTs) that spontaneously accelerated ROS generation in the tumor microenvironment. The BCL family protein pathway that precisely induced cancer cell apoptosis was revealed for the first time.
In conclusion, this thesis provides both theoretical and technical foundations for the development of multifunctional carbon nanotubes‑based systems in biosensing and targeted cancer therapy