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Effect of ambient lighting on frequency dependence in transcranial electrical stimulation-induced phosphenes
No full textInconsistencies have been found in the relationship between ambient lighting conditions and frequency-dependence in transcranial electric stimulation (tES) induced phosphenes. Using a within-subjects design across lighting condition (dark, mesopic [dim], photopic [bright]) and tES stimulation frequency (10, 13, 16, 18, 20 Hz), this study determined phosphene detection thresholds in 24 subjects receiving tES using an FPz-Cz montage. Minima phosphene thresholds were found at 16 Hz in mesopic, 10 Hz in dark and 20 Hz in photopic lighting conditions, with these thresholds being substantially lower for mesopic than both dark (60% reduction) and photopic (56% reduction), conditions. Further, whereas the phosphene threshold-stimulation frequency relation increased with frequency in the dark and decreased with frequency in the photopic conditions, in the mesopic condition it followed the dark condition relation from 10 to 16 Hz, and photopic condition relation from 16 to 20 Hz. The results clearly demonstrate that ambient lighting is an important factor in the detection of tES-induced phosphenes, and that mesopic conditions are most suitable for obtaining overall phosphene thresholds
Highly efficient room-temperature ethylene sensing with molybdenum based transition metal dichalcogenides
No full textDetecting ethylene (C2H4) is essential across various domains, including agricultural logistics, fruit quality control, healthcare, and industry. However, effective C2H4 sensing poses significant challenges due to the molecule’s non-polar nature and the requirement for ultra-high sensitivity at trace concentrations (parts-perbillion, ppb). Traditional C2H4 sensors often rely on costly, complex, and less portable techniques. In this study, we demonstrate the potential of two-dimensional (2D) molybdenum-based transition metal dichalcogenides (TMDs), including MoS2, MoSe2, MoTe2, and their defective/surface-functionalized forms, as effective C2H4 sensors based on portable electrical transduction. Using a combination of theoretical approaches, including density functional theory (DFT), non-equilibrium Green’s functions (NEGF), and thermodynamics analysis by Langmuir adsorption model, we explore the C2H4 sensing capabilities of the mentioned materials. Our findings indicate that pristine TMDs show limited adsorption affinity toward C2H4, but doping with elements such as silicon (Si), germanium (Ge), and tin (Sn) remarkably magnifies their adsorption. Specifically, Si-doped MoS2, Ge-doped MoSe2, and Sn-doped MoTe2 exhibit strong covalent bonding with C2H4 through Si-C, Ge-C, and Sn-C interactions, triggering contrastive modulation of electronic transport upon C2H4 exposure. Among these, Sidoped MoS2 demonstrates outstanding sensitivity and is capable of detecting C2H4 at ppb levels under ambient temperatures. It achieves a sensitivity of 77.9 % with an ultrafast recovery time of 3.79 × 10− 2 ms at 500.0 K, making it a prime candidate for advanced C2H4-sensing applications
Retinal Prosthesis Safety: Alterations in Microglia Morphology due to Thermal Damage and Retinal Implant Contact
No full textPurpose.: In order to develop retinal implants with a large number of electrodes, it is necessary to ensure that they do not cause damage to the neural tissue by the heat that the electrical circuits generate. Knowledge about the threshold of the amount of power that induces damage will assist in developing power budgets for retinal implants. Methods.: Heat-induced retinal damage was evaluated by measuring changes in the morphology of the resident immune cells, the microglia, which are the first cells to respond to retinal trauma. Microglial soma and arbor areas were assessed in rat retinal tissues in vitro to determine the effects of increasing temperatures, implant contact, and heating and implant contact combined. Results.: In response to increasing incubation temperatures (no implant), microglial somas enlarged and arbor areas retracted, indicative of retinal stress. Thermal damage thresholds, defined as a significant change in microglial morphology from that observed at the upper limit of normal body temperature, occurred at a temperature of 38.7°C. Implant contact, induced when a passive implant was placed on the retina, also caused similar morphological alterations in microglia, indicating retinal damage. Heated-implant contact exacerbated the effects of temperature alone but still resulted in a thermal damage threshold of 38.7°C, the same as with heating alone. Conclusions.: Our conservative recommendations are that implanted retinal electronics keep power dissipations to less than 19 mW/mm2 to stay below the microglial thermal damage threshold (2.1°C) and to comply with international standards for implantable devices (2°C)
Reframing Menstruation: Exploring Menstruation, Feminism and Activism on Screen
No full textFor much of screen media history, menstruation has been represented through minor plotlines and brief sequences as an experience marked by shame, embarrassment and trauma, and as such, these portrayals contribute significantly to menstrual stigma. Since 2015, however, there has been a boom in menstrual visibility across media platforms and popular culture, with depictions of unruly menstruators, monstrous menstruation and period sex populating the Anglophone Western media landscape. In this thesis, I propose the term “screen renaissance” to describe the recent cycle of film and television texts produced since 2015 that reflect a growing awareness that menstruation is a complex issue that affects different stages of life and is experienced by diverse groups of people, not just cis-gendered girls and women. This thesis makes visible screen media’s rarely recognised contribution to the cultural reframing of menstruation, which sees an important shift away from stigmatised menstrual narratives towards counterstories of inclusivity, embodiment and resistance. This thesis traces the history of screen media’s problematic framing of menstruation and examines how recent “screen renaissance” narratives respond to and are influenced by the rise of menstrual activism and awareness since 2015. To illustrate the dialogic relationship between screen media and critical menstrual activism, the thesis deploys a thematic structure that combines a comprehensive survey of screen texts with close textual analyses of selected case studies across a range of genres, including (but not limited to) Big Mouth (2017- ), I Love Dick (2016-2017), Broad City (2014-2019), The Witch (2015) and Fleabag (2016-2019). This interdisciplinary project engages with the fields of feminist media studies and critical menstruation studies to investigate how stories of menstruation are told through screen media, specifically film, television and other forms such as social media. As a study of representations, this doctoral project is grounded in the discipline of media and communications, but it has important links with the fields of gender studies and human rights that connect it with broader political and philosophical debates within feminism, and issues of women’s rights, health and wellbeing
The renin-angiotensin system in retinal health and disease: Its influence on neurons, glia and the vasculature
No full textRenin-Angiotensin System is classically recognized for its role in the control of systemic blood pressure. However, the retina is recognized to have all the components necessary for angiotensin II formation, suggestive of a role for Angiotensin II in the retina that is independent of the systemic circulation. The most well-described effects of Angiotensin II are on the retinal vasculature, with roles in vasoconstriction and angiogenesis. However, it is now emerging that Angiotensin II has roles in modulation of retinal function, possibly in regulating GABAergic amacrine cells. In addition, Angiotensin II is likely to have effects on glia. Angiotensin II has also been implicated in retinal vascular diseases such as Retinopathy of Prematurity and diabetic retinopathty, and more recently actions in choroidal neovascularizaiton and glaucoma have also emerged. The mechanisms by which Angiotensin II promotes angiogensis in retinal vascular diseases is indicative of the complexity of the RAS and the variety of cell types that it effects. Indeed, these diseases are not purely characterized by direct effects of Angiotensin II on the vasculature. In retinopathy of prematurity, for example, blockade of AT1 receptors prevents pathological angiogenesis, but also promotes revascularization of avascular regions of the retina. The primary site of action of Angiotensin II in this disease may be on retinal glia, rather than the vasculature. Indeed, blockade of AT1 receptors prevents glial loss and promotes the re-establishment of normal vessel growth. Blockade of RAS as a treatment for preventing the incidence and progression of diabetic retinopathy has also emerged based on a series of studies in animal models showing that blockade of the RAS prevents the development of a variety of vascular and neuronal deficits in this disease. Importantly these effects may be independent of actions on systemic blood pressure. This has culminated recently with the completion of several large multi-centre clinical trials that showed that blockade of the RAS may be of benefit in some at risk patients with diabetes. With the emergence of novel compounds targeting different aspects of the RAS even more effective ways of blocking the RAS may be possible in the future
Short- and long-wavelength lights disrupt endocrine signalling but not immune function in a nocturnal marsupial
No full textNatural light–dark cycles are responsible for synchronizing an animal’s circadian clock with environmental conditions. Consequently, the endocrine system is vulnerable to changes in the external light environment, particularly short-wavelength blue light. Artificial light at night drastically changes the night-time environment by masking natural light cycles and disrupting well-established biological rhythms. The introduction of blue-rich lighting, such as white light-emitting diodes (LEDs), may increase the biological effects of light at night on wildlife. However, flexibility in the spectral composition of LED lighting presents options for wildlife-sensitive lighting, such as long-wavelength amber LEDs. Here we examine the effect of light spectra on circadian physiology in a nocturnal marsupial. Specifically, we investigate the effect of short-wavelength white (standard urban lighting) and long-wavelength amber LEDs (proposed wildlife-sensitive lighting) on circadian hormones and cell-mediated immunity in the Krefft’s glider (Petaurus notatus). Melatonin and glucocorticoid secretion were disrupted following exposure to both short-wavelength white and long-wavelength amber LEDs. Both LEDs suppressed melatonin, whilst glucocorticoid secretion was suppressed under amber LEDs and increased under white LEDs. Despite this disturbance we did not detect any effect of light treatment on cell-mediated immune response. Our findings offer a novel contribution to understanding the physiological impacts of light at night on wildlife. We also provide evidence that long-wavelength amber LEDs can disrupt physiology and are not a wildlife-sensitive lighting option for all species
Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs
No full textModern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in the group of theropod dinosaurs (Maniraptoriformes) that include crown Aves. Squamous or scaly reptilian-like skin is, however, considered the plesiomorphic condition for theropods and dinosaurs more broadly. Here, we review the morphology and distribution of non-feathered integumentary structures in non-avialan theropods, covering squamous skin and naked skin as well as dermal ossifications. The integumentary record of non-averostran theropods is limited to tracks, which ubiquitously show a covering of tiny reticulate scales on the plantar surface of the pes. This is consistent also with younger averostran body fossils, which confirm an arthral arrangement of the digital pads. Among averostrans, squamous skin is confirmed in Ceratosauria (Carnotaurus), Allosauroidea (Allosaurus, Concavenator, Lourinhanosaurus), Compsognathidae (Juravenator), and Tyrannosauroidea (Santanaraptor, Albertosaurus, Daspletosaurus, Gorgosaurus, Tarbosaurus, Tyrannosaurus), whereas dermal ossifications consisting of sagittate and mosaic osteoderms are restricted to Ceratosaurus. Naked, non-scale bearing skin is found in the contentious tetanuran Sciurumimus, ornithomimosaurians (Ornithomimus) and possibly tyrannosauroids (Santanaraptor), and also on the patagia of scansoriopterygids (Ambopteryx, Yi). Scales are surprisingly conservative among non-avialan theropods compared to some dinosaurian groups (e.g. hadrosaurids); however, the limited preservation of tegument on most specimens hinders further interrogation. Scale patterns vary among and/or within body regions in Carnotaurus, Concavenator and Juravenator, and include polarised, snake-like ventral scales on the tail of the latter two genera. Unusual but more uniformly distributed patterning also occurs in Tyrannosaurus, whereas feature scales are present only in Albertosaurus and Carnotaurus. Few theropods currently show compelling evidence for the co-occurrence of scales and feathers (e.g. Juravenator, Sinornithosaurus), although reticulate scales were probably retained on the mani and pedes of many theropods with a heavy plumage. Feathers and filamentous structures appear to have replaced widespread scaly integuments in maniraptorans. Theropod skin, and that of dinosaurs more broadly, remains a virtually untapped area of study and the appropriation of commonly used techniques in other palaeontological fields to the study of skin holds great promise for future insights into the biology, taphonomy and relationships of these extinct animals
Challenging popular conceptions: Observations of a successful Soldier Settlement community in historical context
No full textApplication of a Mechanistic Model to Explore Management Strategies for Biological Control of an Agricultural Pest
No full textDespite the known benefits of integrated pest management, adoption in Australian broadacre crops has been slow, in part due to the lack of understanding about how pests and natural enemies interact. We use a previously developed process-based model to predict seasonal patterns in the population dynamics of a canola pest, the green peach aphid (Myzus persicae), and an associated common primary parasitic wasp (Diaeretiella rapae), found in this cropping landscape. The model predicted aphid population outbreaks in autumn and spring. Diaeretiella rapae was able to suppress these outbreaks, but only in scenarios with a sufficiently high number of female wasps in the field (a simulated aphid: wasp density ratio of at least 5:1 was required). Model simulations of aphid-specific foliar pesticide applications facilitated biological control. However, a broad-spectrum pesticide negated the control provided by D. rapae, in one case leading to a predicted 15% increase in aphid densities compared to simulations in which no pesticide was applied. Biological and chemical control could therefore be used in combination for the successful management of the aphid while conserving the wasp. This modelling framework provides a versatile tool for further exploring how chemical applications can impact pests and candidate species for biological control
Between Identity and Territory: The Ethno-Political Conflict in Rakhine State
No full textThe conflict in Myanmar’s Rakhine State—historically known as Arakan—is one of the most protracted and complex ethno-political crises in Southeast Asia. At its core lies a struggle between the predominantly Buddhist Rakhine (Arakanese) population and the stateless Muslim Rohingya minority, whose contested identity and historical presence in the region have sparked decades of tension, violence, and displacement. The Rakhine people, themselves a marginalized ethnic group within Myanmar, have long harbored grievances against the central government for political and economic neglect. This has fostered a strong regional nationalism, which views the Rohingya not only as religious outsiders but also as demographic and political threats. The Rohingya, on the other hand, claim deep historical roots in the region, yet have been systematically denied citizenship under Myanmar’s 1982 Citizenship Law, rendering them one of the world’s largest stateless populations