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Climate change drives record-breaking heat in Iceland and Greenland challenging cold adapted ecosystems and societies
No full textStudy of the effect of d-block and p-block dopants on material and photocatalytic properties of srtio3
No full textPhotoelectrocatalytic and photocatalytic reactions are gaining momentum as a clean method to generate sustainable fuels such as H2. The Ph.D. study focuses on the identification of suitable d- and p-block dopants and the suitability of doping to enhance the catalytic activity of photochemically stable SrTiO3. In this work, the effect of doping Ga3+, La3+-Ga3+, Cr3+, La3+-Cr3+, and Cs1+-Cr3+ on the properties of SrTiO3 has been extensively studied.
Chapter 1 introduces the state-of-the-art research associated with this field and outlines the motivations and aims of the Ph.D. work. Chapter 2 summarizes the synthesis method, and the characterization techniques employed to study the catalysts.
Chapter 3 studies a series of high-temperature synthesized Ga3+ doped and La3+ co-doped SrTiO3 samples. Accidental exsolutions and anomalous absorption features were observed in some samples. In addition to extrinsic defects, the role of intrinsic defects such as oxygen vacancies in the photoelectrocatalytic performance was investigated.
Chapter 4 studies the Ga3+ doped SrTiO3 synthesized at lower temperatures and how these samples differ in properties from those studied in Chapter 3. This chapter highlights the role of intrinsic material properties like electron affinity and ionization potential and defects such as oxygen vacancies.
Chapter 5 investigates the effect of doping SrTiO3 with Cr in its B-site. Cr mono-doping was found to have formed the Cr6+ (d0 configuration) trap states alongside the Cr3+ states. The bulk of this chapter investigates the effect of the Cr3+/Cr6+ ratio on the material properties and their photoelectrocatalytic performances.
Chapter 6 details the introduction of an additional N2 annealing step in the standard synthesis route to study its effect on crystallite sizes. Preliminary gas phase photocatalytic CO2 hydrogenation with the standard sol-gel Pechini synthesized samples showed an increasing trend in CO evolution and a new method to quantify photocatalytic data has been reported.Open Acces
Towards a unified taxonomy of information dynamics via Integrated Information Decomposition
No full textOur ability to understand and control complex systems of many interacting parts remains limited. A key challenge is that we still don’t know how best to describe – and quantify – the many-to-many dynamical interactions that characterise their complexity. To address this limitation, we introduce the mathematical framework of Integrated Information Decomposition, or ΦID. ΦID provides a comprehensive framework to disentangle and characterise the information dynamics of complex multivariate systems. On the theoretical side, ΦID reveals the existence of previously unreported modes of collective information flow, providing tools to express well-known measures of information transfer, information storage, and dynamical
complexity as aggregates of these modes, thereby overcoming some of their known theoretical shortcomings. On the empirical side, we validate our theoretical results with computational models and examples from over 1,000 biological, social, physical, and synthetic dynamical
systems. Altogether, ΦID improves our understanding of the behaviour of widely-used measures for characterising complex systems across disciplines, and leads to new more refined analyses of dynamical complexity
Quantitative proteomics reveals mechanisms of methotrexate resistance (mtx-r) in gestational trophoblastic neoplasia (gtn) and other cancer types
No full textPatients with low-risk gestational trophoblastic neoplasia (GTN) after a molar/non-molar pregnancy are mostly treated with methotrexate (MTX), but many develop resistance (MTX-R), requiring alternative or more toxic combination therapies to achieve remission. Understanding the molecular mechanisms of MTX-R is crucial for improving treatment. This study employed proteomics profiling of patient tissue samples to explore alterations linked to MTX-R in patients and human choriocarcinoma cell lines.
Bioinformatics analysis identified the Serine Synthesis Pathway (SSP) as significantly downregulated in MTX-R patients and the resistant choriocarcinoma cell line JEG3-R. Phosphoserine aminotransferase 1 (PSAT1), a key SSP enzyme, emerged as a potential prognostic marker for MTX sensitivity in a small patient cohort following Immunohistochemistry (IHC) analysis. Functional studies showed that simultaneous serine deprivation and inhibition of de novo serine synthesis increased MTX resistance in choriocarcinoma cells. Conversely, overexpression of PHGDH and PSAT1, combined with serine and glycine depletion, reversed resistance in JEG3-R cells, restoring MTX sensitivity.
Further experimentation revealed that MTX-R cells exhibit enhanced detoxification capacity, redirecting serine towards glutathione synthesis while downregulating energy-demanding processes like proliferation. This adaptation helps resistant cells mitigate MTX-induced oxidative stress contributing to MTX-R. Investigation into the underlying mechanisms suggested that activation of the Integrated Stress Response (ISR) pathway in JEG3-R cells facilitates translational blockage of non-essential pathways while promoting survival mechanisms such as autophagy. Moreover, dose-specific inhibition of the ISR managed to sensitize JEG3-R cells to MTX indicating a potential therapeutic strategy in the resistant choriocarcinoma.
Finally, SSP downregulation was examined in MTX-sensitive and MTX-resistant breast, colon, and osteosarcoma cell lines. Notably, four of seven MTX-R lines displayed similar SSP downregulation as choriocarcinoma MTX-R cells, reinforcing the role of serine metabolism in MTX response. These findings highlight the potential of SSP as a target for overcoming MTX-R and advancing clinical research.Open Acces
Mixed rainfall trends highlight the importance of climate adaptation in coastal New South Wales
No full textAdolescent exercise capacity predicts higher exercise tolerance later in life when compounded by anaemia in patients with pulmonary arteriovenous malformations
No full textExercise tolerance predicts survival and mental health. To test benefits during adolescence for patients with pulmonary arteriovenous malformations (PAVMs) that cause hypoxaemia, we examined current and retrospective exercise tolerance aged 12y and 19y, linking to clinical records. In the 85 patients (65 female, mean age 56y), current metabolic equivalents ranged from 1.75 to 14.8
(mean 7.85) kcal.kg-1.min-1. Oxygen saturation explained only 2.2% of the variability. There were stronger associations between current exercise tolerance and anaemia indices, particularly the need for blood transfusions. In univariate and multivariate analyses, the
strongest anaemia-independent predictor was exercise tolerance aged 19y. In this cohort, the benefit associated with modestly increased activity by 19y (2.9 METs) was greater than the decrements from severe anaemia (~2.54 METs) or 3 decades of life (2.13 METs). The data support enhanced exercise for people with PAVMs, as for the general population, in preparation for later-life health challenges
A randomized, double-blind, placebo-controlled, Phase 1 study to investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of an immediate-release oral ketamine capsule in healthy volunteers
No full textBackground:
Ketamine, a rapid-acting N-methyl-D-aspartate receptor antagonist used as a therapeutic for treatment-resistant depression (TRD), is usually administered intravenously or intranasally.
Aims:
This randomized, double-blind, placebo-controlled, Phase 1 study investigated safety and tolerability (primary endpoint), pharmacokinetics (PK) and pharmacodynamics (PD) of an immediate-release oral ketamine.
Methods:
Healthy volunteers (18–55 years) were randomized to each receive two single doses of oral ketamine (40–240 mg) and one oral placebo dose. Treatment-emergent adverse events (TEAEs) and PK and PD assessments (e.g., Bond and Lader visual analogue scale, Modified Observer’s Assessment of Alertness/Sedation Scale) were assessed up to 24 h after dosing. Descriptive statistics were used.
Results:
Nineteen participants were randomized (mean age: 31 years; male, 68%); 18 completed the study. Eighty mild or moderate TEAEs were reported following oral ketamine (40–240 mg) and five following placebo. There were no TEAE-related discontinuations. Most TEAEs (86%) were considered probably related to study drug. The most common TEAEs with oral ketamine were dissociation (26 events), dizziness (nine events) and headache (nine events). A positive relationship between increasing ketamine doses and dissociation events was observed. PK parameters (Cmax, AUCinf) of oral ketamine and its primary metabolites (2S,6S;2R,6R-hydroxynorketamine, R/S-norketamine) were dose proportional. Transient changes in mood and dissociation were detected 1 h postdose with a return to predose values after ~4 h.
Conclusions:
There were no unexpected safety signals with oral ketamine. PK properties were consistent with those reported for other rapid-acting formulations. These findings warrant further investigation of oral ketamine capsules in TRD (EudraCT No. 2019-001019-22)
Non-archimedean periods for log calabi-yau surfaces
No full textNon-archimedean geometry has proven to be a very powerful technique to study classical problems in algebraic geometry. Whilst non-archimedean analytic spaces can be very complicated, there exists a canonical combinatorial subspace, called the essential skeleton, which retains a lot of geometric information. In this thesis, we explore how much information the skeleton of a non-archimedean analytic space captures. Our methods are directly inspired by mirror symmetry and the SYZ conjecture, in which non-archimedean geometry plays a fascinating role as first observed by Kontsevich and Soibelman.
Using the non-archimedean SYZ fibration, we study the notion of non-archimedean periods on the essential skeleton as introduced by Kontsevich and Soibelman. We prove that the non-archimedean period map recovers the analytic periods for log Calabi-Yau surfaces, verifying a conjecture of Kontsevich and Soibelman in this case.Open Acces
Data-driven spatial sparsity for convolutional neural networks
No full textAdvancements in Convolutional Neural Networks (CNNs) have driven significant research efforts towards optimizing their effectiveness and applicability. A promising yet less explored path lies in leveraging spatially adaptive computation within networks—an approach aimed at reducing computation redundancy and bolstering overall efficiency. This work investigates the presence of computational redundancy within CNN computations in vision tasks, and explores dynamic optimization methodologies to increase model efficiency.
Firstly, the thesis explores the balance between accuracy and computational cost in stereo matching CNNs. Employing a data-driven strategy, it seeks to control this trade-off by harnessing spatially adaptive computation to minimize redundant computations effectively. By skipping computations in specific locations, our findings indicate that the efficiency of stereo-matching CNNs can be improved while maintaining accuracy.
Expanding the scope, the work tackles the optimization of semantic segmentation CNNs, focusing on either Floating Point Operations (FLOPs) or practical latency. This is achieved through a data-driven optimization methodology which leverages spatially adaptive processing, aiming to meet a specified target budget. When considering practical latency, execution time measurements from target devices are introduced to guide the optimization process.
Lastly, the multifaceted challenge of performing inference at multiple computational budgets while considering the memory footprint of the model weights is explored. Employing spatially adaptive dynamic execution methods, the goal is to strike a balance between memory constraints and computational efficiency, addressing the challenge of optimizing models within restricted memory environments, when multiple performance points are required.
In conclusion, this study explores optimization of CNNs for vision tasks including stereo matching, semantic segmentation and image classification, probing the potential to balance accuracy against multiple axes by considering FLOPs, latency, and memory. It aims to leverage spatially adaptive computation, dynamic data-driven techniques, and novel architectures to enhance efficiency, offering a holistic approach that navigates the trade-offs and boundaries of neural network optimization.Open Acces
Nomophobia and associated sociodemographic factors among respiratory therapists in Saudi Arabia
No full textBackground
Nomophobia, the fear of being without a smartphone or disconnected from mobile networks, has become a growing concern in today’s digital era, impacting mental health and professional productivity. This study assesses the prevalence of nomophobia among respiratory therapy (RT) staff in Saudi Arabia and examines sociodemographic factors associated with moderate to severe levels of nomophobia, offering insights into digital dependency within this healthcare workforce.
Methods
A nonprobability cross-sectional survey, utilizing the Nomophobia Questionnaire (NMP-Q), was distributed via social media platforms to respiratory therapists (RTs) in Saudi Arabia from October 17, 2022, to January 13, 2023. Data were presented in terms of frequency and percentage, and logistic regression analysis was conducted to identify factors associated with moderate to severe nomophobia.
Results
Overall, 1,001 RTs completed the online survey. The prevalence of nomophobia among RT staff was 95% (95% CI 67–94), with a mean ± SD of 56 ± 20, indicating a mild level of nomophobia among the participants. Female RT staff were one time more likely to experience moderate to severe levels of nomophobia [OR: 1.4 (95% CI 1.06–1.85); p = 0.019]. RT staff with work experience ≥ 11 years were twice as likely to experience moderate to severe levels of nomophobia [OR: 2.07 (95% CI 1.28–3.34); p = 0.003]. Staff who reported active smoking status were almost twice as likely to experience moderate to severe levels of nomophobia [(OR): 1.79 (1.24–2.60); p = 0.045]. Finally, RT staff who worked in private hospitals were one time more likely to experience moderate to severe levels of nomophobia [(OR): 1.4 (1.01–1.95); p = 0.002].
Conclusions
Nomophobia is prevalent among respiratory therapy staff in Saudi Arabia, with a majority experiencing moderate to severe levels. The identification of key sociodemographic risk factors associated with this condition underscores the need for targeted interventions and support strategies to improve both the well-being and productivity of the workforce