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A systematic study of the effect of lipid architecture on cytotoxicity and cellular uptake of cationic cubosomes
No full textHypothesis: Lipid nanoparticles containing a cationic lipid are increasingly used in drug and gene delivery as they can display improved cellular uptake, enhanced loading for anionic cargo such as siRNA and mRNA or exhibit additional functionality such as cytotoxicity against cancer cells. This research study tests the hypothesis that the molecular structure of the cationic lipid influences the structure of the lipid nanoparticle, the cellular uptake, and the resultant cytotoxicity. Experiments: Three potentially cytotoxic cationic lipids, with systematic variations to the hydrophobic moiety, were designed and synthesised. All the three cationic lipids synthesised contain pharmacophores such as the bicyclic coumarin group (CCA12), the tricyclic etodolac moiety (ETD12), or the large pentacyclic triterpenoid “ursolic” group (U12) conjugated to a quaternary ammonium cationic lipid containing twin C12 chains. The cationic lipids were doped into monoolein cubosomes at a range of concentrations from 0.1 mol% to 5 mol% and the effect of the lipid molecular architecture on the cubosome phase behaviour was assessed using a combination of Small Angle X-Ray Scattering (SAXS), Dynamic Light Scattering (DLS), zeta-potential and cryo-Transmission Electron Microscopy (Cryo-TEM). The resulting cytotoxicity of these particles against a range of cancerous and non-cancerous cell-lines was assessed, along with their cellular uptake. Findings: The molecular architecture of the cationic lipid was linked to the internal nanostructure of the resulting cationic cubosomes with a transition to more curved cubic and hexagonal phases generally observed. Cubosomes formed from the cationic lipid CCA12 were found to have improved cellular uptake and significantly higher cytotoxicity than the cationic lipids ETD12 and U12 against the gastric cancer cell-line (AGS) at lipid concentrations ≥ 75 µg/mL. CCA12 cationic cubosomes also displayed reasonable cytotoxicity against the prostate cancer PC-3 cell-line at lipid concentrations ≥ 100 µg/mL. In contrast, 2.5 mol% ETD12 and 2.5 mol% U12 cubosomes were generally non-toxic against both cancerous and non-cancerous cell lines over the entire concentration range tested. The molecular architecture of the cationic lipid was found to influence the cubosome phase behaviour, the cellular uptake and the toxicity although further studies are necessary to determine the exact relationship between structure and cellular uptake across a range of cell lines
Design and construction of catenary-ruled surfaces
No full textThe past two decades have witnessed an increasing adoption of double-curved surfaces in architectural design and building construction. However, their shape complexity has brought a great challenge in design and construction, typically leading to high modeling and construction costs. In this study, a new geometry family, termed catenary-ruled surface, is proposed. They can be conveniently created using catenary rulings based on the transformation of line rulings, thereby offering new possibilities for designing a wide variety of architectural forms. Moreover, this paper uses a physical model to demonstrate that a specific group of catenary-ruled surfaces can be effectively and inexpensively constructed using a proposed string actuation system. This is achieved by using a series of foldable arches to form the target surface, with their folding motion controlled by simply pulling external strings. The constructed structure with catenary rulings can act as an efficient structural system that is predominantly under pure compression
Accounts and counter-accounts: accounting and accountability for asbestos-related liabilities
No full textPurpose: This study aims to investigate disclosure of asbestos-related liabilities in corporate accounts and counter-accounts to examine whether and how accounting contributes to corporate accountability for asbestos-contaminated products. Design/methodology/approach: This study uses the Goffmanesque perspective on impression management to examine instances of concealed asbestos-related liabilities in corporate accounts vis-à-vis the revealing of such liabilities in counter-accounts. Findings: The findings show counter-accounts provide significant information on liabilities originating from the exposure of employees and consumers to asbestos. By contrast, the malleability of accounting tools enables companies to eschew accounting disclosures. While the frontstage positive performance of companies served an impression management role, their backstage concealing actions enabled companies to cover up asbestos-related liabilities. These companies used three categories of mechanisms to avoid disclosure of asbestos-related liabilities: concealing via a “cloak of competence”, impression management via epistemic work and a silent strategy of concealment frontstage with strategic reorganisation backstage. Practical implications: This study has policy relevance as regulators need to consider the limits of corporate disclosures as an accountability tool. The findings may also initiate academic and practitioner conversations about accounting standards for long-term liabilities. Originality/value: This study highlights the strategies companies use both frontstage and backstage to avoid disclosing asbestos-related liabilities. Through analysis of accounts and counter-accounts, this study identifies the limits of accounting as an accountability tool regarding asbestos-induced diseases and deaths
Heat-induced changes of milk protein concentrate suspensions as affected by addition of calcium sequestering salts and shearing
No full textCalcium sequestering salts (CSS) such as disodium hydrogen phosphate (DSHP) and trisodium citrate (TSC) can be used to improve the heat stability and solubility of milk proteins during thermal processing. Shearing is also an inherent part of food processing that can alter protein properties and functionality. The heat stability of milk proteins was investigated under combined temperatures (90 °C/5 min; 121 °C/2.6 min) and shear (100, 1000, 1500 s−1) with 10, 20, or 30 mM DSHP or TSC. The calcium-binding capacity of individual CSS predominantly determined the impact of shear. With DSHP, the effect of shear was more pronounced at high temperatures and shear rates than with TSC. The significant influence of shear on casein micelles in DSHP-containing dispersions suggested that DSHP's lower calcium binding affinity minimised micellar disruption and led to a pronounced shear impact. Shear combined with heat considerably impacts the milk system in the presence of CSS
Fabrication of Sb2Se3-based high-performance self-powered Visible-NIR broadband photodetector
No full textAntimony selenide (Sb2Se3) is a narrow-band gap semiconductor with tuneable optoelectronic properties. It has recently gained significant attention due to its unique crystal structure, high carrier transport, stability, ease of processing, and inexpensiveness. Further, Sb2Se3 thin films have been successfully utilized in photovoltaics; however, their application in photodetectors is still unexplored. Herein, we report the fabrication of a Sb2Se3-based self-powered, broad-band photodetector using Sb2Se3 thin film deposited by a simple thermal evaporation technique. The fabricated photodetector (PD) exhibited exceptional performance, featuring a broad absorption band covering the visible to the infrared wavelength region and high responsivity of 3.37AW-1. The Vis-IR PD demonstrates outstanding figure-of-merit performance parameters such as specific detectivity of 1.0×1011 Jones, external quantum efficiency of 369.3%, with noise equivalent power of 2.95×10-13 WHz-1/2. In addition, the device displays excellent photodetection performance under self-power (at zero applied bias) conditions with a responsivity of 3.02 mAW-1 with long-term stability. The performance of Sb2Se3 photodetectors is attributed to the excellent crystallinity of the Sb2Se3 thin film and the strong electric field established at the interface between Sb2Se3 and Au, which facilitates the efficient separation of photogenerated electron-hole pairs. These findings open up new avenues for Sb2Se3-based photodetectors in optoelectronics
Can inflation predict energy price volatility?
No full textFluctuations in energy prices impact production costs and inflation. This study examines whether inflation data can predict volatility in energy markets. Both inflation and energy market volatility exhibit complex behaviour over time, including structural shifts due to demand and supply shocks. Accounting for differences in data frequencies, we use an extended GARCH model (MIDAS) with Laguerre polynomials for time-varying parameters. The empirical results demonstrate that including low-frequency inflation data enhances energy model predictability particularly during periods of high volatility and extreme price fluctuations. Considering inflation improves forecasting for energy market models, benefiting portfolio management and helping policymakers manage inflation
Digital distortions and interpretive choices: A cartographic perspective on encoding regulation
No full textRules as Code (RaC), which encompasses the conversion of legal and regulatory rules into computer code, is gaining traction internationally. This article analyses ‘digital distortions’ in RaC, which refer to disconnects between regulation and code that arise from interpretive choices in the encoding process. We contend that Boaventura de Sousa Santos’ ‘symbolic cartography of law’ provides valuable concepts for understanding digital distortions in encoding regulation. Specifically, we argue that the cartographic concepts of scale, projection, symbolisation and orientation highlight distortions that can arise from choices involving the documentation to code, logics to follow, languages to use and coded outputs to present. We demonstrate how these distortions arose in our attempt to convert the ePayments Code, an Australian voluntary code of conduct for consumer electronic payment transactions, into machine-executable code. The article concludes by underscoring the importance of greater awareness of interpretive coding choices and their implications for diverse users of digitised regulation
Virtual community engagement: Engaging virtual communities for nation branding through sports
No full textMajor sporting events bring a range of social, economic, and reputational benefits for hosting nations and serve as a vehicle to showcase the nation brand. Social media engagement during sport events provides opportunities for community members to cocreate, curate and communicate their nation brand’s attributes. While research in nation branding and community engagement has examined the ways place-based communities contribute to nation branding, little is known about how and in what ways virtual communities contribute to their nation brand. This study addresses this gap by examining the virtual brand community (VBC) surrounding the 2022 Beijing Winter Olympics. Using social network analysis and content analysis, the findings suggest that VBC contributions is dependent on the composition, participation, and cultivation of conversations focusing on the personality traits of a nation brand. Theoretically, the outcomes from this study advance understanding of leveraging the properties of VBCs in making contribution to the production and maintenance of an authentic nation brand, that values community perspectives facilitated through community engagement. For public relations, it extends the current research in digital social-level engagement in virtual settings and outlines future research in participatory approaches to nation branding. The growing use of major sporting events in supporting nation branding goals, particularly in Asian and African continents, suggests the outcome of this study has implications at regional and international levels to guide public relations managers in major events to facilitate sustainable VBCs for authentic place branding outcomes.</p
NEST3D printed bone-mimicking scaffolds: assessment of the effect of geometrical design on stiffness and angiogenic potential
No full textTissue-engineered implants for bone regeneration require consideration regarding their mineralization and vascularization capacity. Different geometries, such as biomimetic designs and lattices, can influence the mechanical properties and the vascularization capacity of bone-mimicking implants. Negative Embodied Sacrificial Template 3D (NEST3D) printing is a versatile technique across a wide range of materials that enables the production of bone-mimicking scaffolds. In this study, different scaffold motifs (logpile, Voronoi, and trabecular bone) were fabricated via NEST3D printing in polycaprolactone to determine the effect of geometrical design on stiffness (10.44 ± 6.71, 12.61 ± 5.71, and 25.93 ± 4.16 MPa, respectively) and vascularization. The same designs, in a polycaprolactone scaffold only, or when combined with gelatin methacryloyl, were then assessed for their ability to allow the infiltration of blood vessels in a chick chorioallantoic membrane (CAM) assay, a cost-effective and time-efficientin ovoassay to assess vascularization. Our findings showed that gelatin methacrylolyl alone did not allow new chorioallantoic membrane tissue or blood vessels to infiltrate within its structure. However, polycaprolactone on its own or when combined with gelatin methacrylolyl allowed tissue and vessel infiltration in all scaffold designs. The trabecular bone design showed the greatest mineralized matrix production over the three designs tested. This reinforces our hypothesis that both biomaterial choice and scaffold motifs are crucial components for a bone-mimicking scaffold.</p
Australian Teachers’ Perspectives on Children’s Television and Screen Media in Education
No full textAustralian Children’s Television Cultures (ACTC) is a research project based at Swinburne University of Technology, Melbourne, in collaboration with RMIT University. In partnership with the Australian Children’s Television Foundation (ACTF), ACTC are undertaking a four-year project to investigate the roles of Australian children’s television and other children’s screen entertainment in people’s lives, memories, families, and education. The findings and outcomes of this project are designed to inform the Australian children’s television sector as it navigates an era of increased viewing options, policy changes, and new viewing practices.This report presents findings from research that sought to better understand how and why Australian educators use (and/or do not use) children’s screen media – especially Australian children’s screen media – in the teaching and learning programs of primary schools and high schools. This study explores how contemporary Australian educators incorporate screen media and ancillary screen media resources in their lessons, with a particular focus on television given the medium’s decades-long ties with education. The mixed-method study involved a survey of 106 primary and secondary school educators from across Australia and 17 semi-structured interviews with teachers, as well as educators in school leadership roles.PUBLISHERSwinburne University of Technology and RMIT University</p