62880 research outputs found
Sort by
The effects of the venom of the Tarantula spiders Poecilotheria regalis and Thrixopelma pruriens on skeletal muscle damage and nociception
No full textThe venoms of some spider species are medically relevant, causing skeletal muscle damage
and pain, while others are being bioprospected for potentially useful components. These
factors justify the examination of their biochemical activity and their effects in vitro and in vivo.
Two tarantula spider venoms were studied in this work, the Poecilotheria regalis and the
Thrixopelma pruriens. The P. regalis venom has limited content characterisation and
reportedly causes muscle damage symptoms and severe pain, while some T. pruriens venom
toxins are instead being developed as analgesics, despite one having an affinity for a sodium
ion channel related to muscle excitability. Muscle’s innate regenerative capacity for repair
requires stem cells called satellite cells which become myoblasts. Their survival, migration,
and fusion into myotubes can be impacted by venoms, which can also induce atrophy.
Undifferentiated myoblasts in vitro were unaffected by either venom. However, both inhibited
fusion and induced atrophy in the C2C12 mouse muscle cell line, in contrast to the AB1190
cell line from human paravertebral muscle. Treatment of atrophy from P. regalis venom by
soluble activin receptor type IIB was investigated, however, improvement was not found. The
in vivo study found that P. regalis caused muscle damage and delayed regeneration including
some aspects unresolved by day 20. Nociception related to pain from P. regalis venom was
also studied in vivo. Neuronal activity was quantified in mouse spinal cords, with a trend of
increased reactive oxygen species, which supports published observations of hyperalgesia or
pain sensitivity. In a preliminary in vivo study T. pruriens venom appeared to cause only
localised minor skeletal muscle damage, even at a higher concentration than P. regalis venom.
Overall, this study gives novel insight into the two venom’s activities in skeletal muscle and
quantifiable nociception-related measures caused by a tarantula venom, as well as suggesting
mechanisms
Rational design and optimisation of polymer microneedles for drug delivery
Get PDFMicroneedles (MNs) are promising drug delivery systems which enable the delivery of
drugs of various physicochemical properties into and across the skin by breaching the
skin barrier. Dissolving MNs are a type of MNs which release the incorporated drug by
dissolving or degrading in the skin upon contact with the skin’s interstitial fluid. Polymers
are commonly used to fabricate dissolving MNs, but their mechanical properties limit
efficient skin insertion. Therefore, there is a need to identify additional polymers which
can create high quality MNs and potentially broaden the applicability of dissolving MNs.
This thesis investigated the feasibility of fabricating dissolving MNs from poly(2-ethyl-oxazoline) (PEOZ) of two molecular weights (50 kDa and 200 kDa) and used
polyvinylpyrrolidone (PVP) MNs as a benchmark to evaluate the suitability of PEOZ for
fabricating MNs. Findings from the characterisation studies suggest that PEOZ 200 kDa
is a promising MN material with comparable performance to PVP whereas sole use of
PEOZ 50 kDa is not suitable for MN fabrication.
PEOZ 50 kDa was then blended with poly(vinyl alcohol) (PVA) to assess for miscibility
between the polymers in order to improve PEOZ 50 kDa MNs by polymer blending.
Polymer miscibility was evaluated by using a combination of various analytical
techniques, providing useful insights into polymer miscibility and the potential
applications of PEOZ-PVA blends.
This thesis also showcases an innovative approach to treating cutaneous leishmaniasis
(CL) by loading paromomycin into dissolving MNs and tailoring the MN composition to
the disease. Characterisation studies suggest that the use of paromomycin-containing
dissolving MNs is a promising approach to treating CL. Suggestions of additional studies
are also proposed to further explore this drug delivery system. Studies towards
developing a sensitive assay for quantifying paromomycin in MNs are also described,
providing useful insights into paromomycin quantification by liquid chromatography and
mass spectrometry
Future changes in winter-time extratropical cyclones over South Africa from CORDEX-CORE simulations
Get PDFExtratropical cyclones (ETCs) significantly impact mid-latitude weather patterns and are crucial for understanding the societal implications of regional climate variability, climate change, and associated extreme weather. In this study, we examine the projected future changes in winter-time ETCs over South Africa (SA) using simulations from CORDEX-CORE Africa. We utilized three regional climate models (RCMs), each driven by three different global climate models (GCMs) that simulate both the current climate and a future climate experiencing strong human-induced warming. From these, we assess changes in ETC frequency, track density, intensity, storm severity, and associated rainfall. The results indicate a significant reduction in the aggregate ETC frequency and track density, although track density is projected to increase prominently along the western coastal regions. Intensity projections show mixed trends, with an aggregate decrease in peak relative vorticity and an increase in minimum mean sea level pressure, suggesting weaker future cyclones. Examining the Meteorological Storm Severity Index (METSSI) reveals notable regional variations in future storm severity. Average rainfall associated with ETCs is projected to decrease across SA, especially around Cape Town, highlighting a potential shift in the spatial distribution of rainfall with substantial consequences for water supply. We further investigated extreme ETCs (EETCs) and found that the trends for EETCs are generally similar to those for ETCs, with a notable decrease in frequency but regional variations in storm severity. These findings underscore the importance of developing targeted adaptation strategies to address the projected impacts of future ETCs on SA’s climate and communities
A systematic literature review of Chinese investment in natural resource-rich and technology-intensive locations
Get PDFWith China's economy transitioning into a post-industrial phase focused on knowledge and technology, there has been a notable shift in the patterns of Chinese Outward foreign direct investment (OFDI). This change has led to the emergence of new research perspectives, underscoring the importance of organizing them systematically. To address this, our research presents a thorough analysis of eighty-eight publications examining Chinese OFDI in natural resource-rich (NRR) and technology-intensive (TI) locations across various global regions and countries. Based on the geographical scope and comprehensive coverage of studies published between 1998 and 2023, we summarize the major themes, theories, and methodologies used in this research area. Identifying three elements related to Chinese investment (antecedents and motives, operational strategies and investment outcomes), we develop a matrix based on the discussion of Chinese firms’ investment behavior in the foreign environment in which they operate. We describe the theoretical distinctions between investments in NRR global regions, such as Africa and Central Asia, and TI regions, such as Europe and North America, with regard to technology acquisition, creation, co-creation, and transfer. We identify several research sub-themes (e.g., control and learning mechanisms, technology transfer, intellectual property, etc.) that remain under-investigated and suggest future research opportunities
Incorporating circularity, sustainability, and systems thinking into an assessment framework for transformative food system innovation
Get PDFThe transition towards a circular economy in the food system is posited as way to harmonise the provision safe, ample and accessible food to a growing population with the reduction the food system's widespread impact on natural resources, the environment, and human health. Within the context of circular food innovation, there is an abundance of assessment approaches allowing researchers to evaluate and guide new technologies, applications, and products. However, specialist circularity tools are underutilised. This research draws from wider circular economy discourse, sustainability assessment methods, and systems-transitions theory to propose a novel framework to appraise and guide circular food innovation. Through a systematic literature review and critical analysis, this work highlights the limitations of existing methods based on a multi-disciplinary lens. In lieu of robust circularity metrics, elaborations within the Life Cycle Assessment (LCA) methodology provide a comprehensive sustainability and circularity assessment, while crossdisciplinary approaches inform the development of technological trajectories in line with systemtransitions theories. The proposed framework aims to bridge this gap by providing a holistic approach that incorporates systems perspectives and considers the wider dynamics of sustainability and circular economy via future scenario modelling. By integrating these perspectives, the framework facilitates earlier intervention and broader stakeholder engagement in the sustainability assessment process. Examined primarily within the context of food manufacturing, this work provides new tools for academic research and industrial practitioners, driving transformative change towards a more sustainable and circular food system
The Impact of artificial intelligence on corporate greenwashing: evidence from the Chinese listed firms
Get PDFPurpose
This paper investigates the impact of AI penetration rate on the degree of corporate greenwashing, and aims to assess the potential of AI in enhancing firms' environmental performance and reducing false disclosures.
Design/methodology/approach
This study employs a year and firm fixed-effects model to analyze data from Chinese listed firms from 2012 to 2022. We use the low-carbon city pilot as a quasi-natural experiment to address endogeneity concerns and conduct a series of robustness tests, including adding control variables and transforming the model.
Findings
The results of this paper show that the application of AI can inhibit firms' greenwashing behavior, with green innovation activities further enhancing this inhibitory effect. In state-owned firms and those with Party organizations, the inhibitory effect of AI on corporate greenwashing is more significant. This reduction in greenwashing is more likely to be observed in firms that are heavily influenced by Confucian culture, receive higher public attention regarding their environmental impact, face less market competition, suffer from more serious pollution, and face less financial constraints.
Originality/value
We propose a new research perspective that offers novel insights into promoting the green development of firms by revealing the potential of AI in reducing their greenwashing behavior. Corporate managers can explore specific strategies for applying AI to monitor, prevent, and correct greenwashing, thereby enhancing corporate environmental performance and social responsibility
Institutional context matters: board diversity and ESG outcomes in the UAE
Get PDFPurpose
This study empirically examines the impact of board diversity on environmental, social and governance (ESG) outcomes in organizations from the United Arab Emirates (UAE). The study aims to extend prior literature by covering the impacts of the institutional context on board diversity and ESG outcomes.
Design/methodology/approach
Using a thematic analysis of interviews with 42 UAE board members, this research uncovers the effects of institutional context on ESG outcomes. The study focuses on the impact of culture, the influence of regulatory bodies and the relationship between critical board diversity traits and ESG.
Findings
Three major themes emerged from the data: the impact of institutional context and culture, the impact of regulatory bodies and critical board diversity traits’ relationship with ESG. The findings indicate that the institution’s cultural and regulatory context impacts board diversity and ESG. The findings also demonstrate that the board’s functional diversity (educational and occupational diversity) and age diversity impact ESG outcomes.
Originality/value
This research contributes to resource dependence theory by indicating the specific resources diverse directors bring to a corporate board. The study also highlights how institutional context dictates the types of resources directors seek for effective ESG implementation, providing a novel insight into board diversity’s role in ESG performance
Comparative evaluation of learning technologies using a randomized controlled trial: Virtual reality, augmented reality, online video platforms, and traditional classroom learning
Get PDFThe COVID-19 pandemic has propelled the use of technology in education through platforms such as YouTube and immersive technologies such as virtual reality (VR) and augmented reality (AR). Despite their potential to improve equity, access, engagement, and cognitive achievement, rigorous studies comparing their impacts on learning outcomes are scarce. This study investigated the effects of educational technologies such as YouTube, AR, and VR on student learning outcomes compared to conventional classroom learning. It focuses on the lower cognitive levels in Bloom’s taxonomy. With a sample of 139 higher education institution students, participants were randomly assigned to four groups: classroom (control), YouTube, AR, and VR. Two-way ANOVA and post-hoc pairwise comparisons were conducted to evaluate the impact of learning environments and cognitive levels on learning outcomes. Contrary to existing literature, the findings indicated that VR did not surpass conventional classroom learning. This finding suggests the need to develop pedagogies that are appropriate for virtual scenarios. Additionally, no significant differences were observed between YouTube and VR. Within the three cognitive levels of learning, learning in AR had the highest impact at the cognitive level of understanding compared to other learning environments
Incorporating the acclimation of photosynthesis and leaf respiration in the Noah‐MP land surface model: model development and evaluation
Get PDFRealistic simulation of leaf photosynthetic and respiratory processes is needed for accurate prediction of the global carbon cycle. These two processes systematically acclimate to long-term environmental changes by adjusting photosynthetic and respiratory traits (e.g., the maximum photosynthetic capacity at 25°C (Vcmax,25) and the leaf respiration rate at 25°C (R25)) following increasingly well-understood principles. While some land surface models (LSMs) now account for thermal acclimation, they do so by assigning empirical parameterizations for individual plant functional types (PFTs). Here, we have implemented an Eco-Evolutionary Optimality (EEO)-based scheme to represent the universal acclimation of photosynthesis and leaf respiration to multiple environmental effects, and that therefore requires no PFT-specific parameterizations, in a standard version of the widely used LSM, Noah MP. We evaluated model performance with plant trait data from a 5-year experiment and extensive global field measurements, and carbon flux measurements from FLUXNET2015. We show that observed R25 and Vcmax,25 vary substantially both temporally and spatially within the same PFT (C.V. >20%). Our EEO-based scheme captures 62% of the temporal and 70% of the spatial variations in Vcmax,25 (73% and 54% of the variations in R25). The standard scheme underestimates gross primary production by 10% versus 2% for the EEO-based scheme and generates a larger spread in r (correlation coefficient) across flux sites (0.79 ± 0.16 vs. 0.84 ± 0.1, mean ± S.D.). The standard scheme greatly overestimates canopy respiration (bias: ∼200% vs. 8% for the EEO scheme), resulting in less CO2 uptake by terrestrial ecosystems. Our approach thus simulates climate-carbon coupling more realistically, with fewer parameters