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Optomechanical switching of adsorption configurations of polar organic molecules by UV radiation pressure
Get PDFUsing photoemission spectroscopy (PES), we have systematically investigated the behavior of polar organic molecule, chloroaluminum phthalocyanine (ClAlPc), adsorbed in the Cl-down configuration on the Ag(111) substrate at low temperature − 195 °C under UV irradiation with a range of different photon fluxes. Judging from the evolution of photoemission spectral line shapes of molecular energy states, we discovered that the Cl atoms are so robustly anchored at Ag(111) that the impinging photons cannot flip the ClAlPc molecules, but instead they crouch them down due to radiation pressure; we observe that the phthalocyanine (Pc) lobes bend down to interact with Ag atoms on the substrate and induce charge transfer from them. As photon flux is increased, radiation pressure on the Pc plane initiates tunneling of the Cl atom through the molecular plane to turn the adsorption configuration of ClAlPc from Cl-down to an upheld Cl-up configuration, elucidating an optomechanical way of manipulating the dipole direction of polar molecules. Finally, work function measurements provide a distinct signature of the resulting upheld Cl-up configuration as it leads to a large increase in vacuum level (VL), ~ 0.4 eV higher than that of a typical flat-on Cl-up configuration driven by thermal annealing
Oral etoposide as a single agent in childhood and young adult cancer in England: Still a poorly evaluated palliative treatment
Get PDFFrom Wiley via Jisc Publications RouterHistory: received 2020-10-27, rev-recd 2021-06-04, accepted 2021-06-16, pub-electronic 2021-07-06Article version: VoRPublication status: PublishedAbstract: Background: Oral etoposide is commonly used in palliative treatment of childhood and young adult cancer without robust evidence. We describe a national, unselected cohort of young people in England treated with oral etoposide using routinely collected, population‐level data. Methods: Patients aged under 25 years at cancer diagnosis (1995–2017) with a treatment record of single‐agent oral etoposide in the Systemic AntiCancer Dataset (SACT, 2012–2018) were identified, linked to national cancer registry data using NHS number and followed to 5 January 2019. Overall survival (OS) was estimated for all tumours combined and by tumour group. A Cox model was applied accounting for age, sex, tumour type, prior and subsequent chemotherapy. Results: Total 115 patients were identified during the study period. Mean age was 11.8 years at cancer diagnosis and 15.5 years at treatment with oral etoposide. Median OS was 5.5 months from the start of etoposide; 13 patients survived beyond 2 years. Survival was shortest in patients with osteosarcoma (median survival 3.6 months) and longest in CNS embryonal tumours (15.5 months). Across the cohort, a median of one cycle (range one to nine) of etoposide was delivered. OS correlated significantly with tumour type and prior chemotherapy, but not with other variables. Conclusions: This report is the largest series to date of oral etoposide use in childhood and young adult cancer. Most patients treated in this real world setting died quickly. Despite decades of use, there are still no robust data demonstrating a clear benefit of oral etoposide for survival
Use of Gaussian process regression for radiation mapping of a nuclear reactor with a mobile robot
Get PDFFrom Springer Nature via Jisc Publications RouterHistory: received 2021-03-05, accepted 2021-06-04, registration 2021-06-25, pub-electronic 2021-07-07, online 2021-07-07, collection 2021-12Publication status: PublishedAbstract: Collection and interpolation of radiation observations is of vital importance to support routine operations in the nuclear sector globally, as well as for completing surveys during crisis response. To reduce exposure to ionizing radiation that human workers can be subjected to during such surveys, there is a strong desire to utilise robotic systems. Previous approaches to interpolate measurements taken from nuclear facilities to reconstruct radiological maps of an environment cannot be applied accurately to data collected from a robotic survey as they are unable to cope well with irregularly spaced, noisy, low count data. In this work, a novel approach to interpolating radiation measurements collected from a robot is proposed that overcomes the problems associated with sparse and noisy measurements. The proposed method integrates an appropriate kernel, benchmarked against the radiation transport code MCNP6, into the Gaussian Process Regression technique. The suitability of the proposed technique is demonstrated through its application to data collected from a bespoke robotic system used to conduct a survey of the Joz̆ef Stefan Institute TRIGA Mark II nuclear reactor during steady state operation, where it is shown to successfully reconstruct gamma dosimetry estimates in the reactor hall and aid in identifying sources of ionizing radiation
Simulating Ionising Radiation in Gazebo for Robotic Nuclear Inspection Challenges
Get PDFFrom MDPI via Jisc Publications RouterHistory: accepted 2021-07-02, pub-electronic 2021-07-07Publication status: PublishedFunder: UK Research and Innovation; Grant(s): EP/P018505/1, EP/R026084/1Funder: Royal Academy of Engineering; Grant(s): CiET1819\13The utilisation of robots in hazardous nuclear environments has potential to reduce risk to humans. However, historical use has been largely limited to specific missions rather than broader industry-wide adoption. Testing and verification of robotics in realistic scenarios is key to gaining stakeholder confidence but hindered by limited access to facilities that contain radioactive materials. Simulations offer an alternative to testing with actual radioactive sources, provided they can readily describe the behaviour of robotic systems and ionising radiation within the same environment. This work presents a quick and easy way to generate simulated but realistic deployment scenarios and environments which include ionising radiation, developed to work within the popular robot operating system compatible Gazebo physics simulator. Generated environments can be evolved over time, randomly or user-defined, to simulate the effects of degradation, corrosion or to alter features of certain objects. Interaction of gamma radiation sources within the environment, as well as the response of simulated detectors attached to mobile robots, is verified against the MCNP6 Monte Carlo radiation transport code. The benefits these tools provide are highlighted by inclusion of three real-world nuclear sector environments, providing the robotics community with opportunities to assess the capabilities of robotic systems and autonomous functionalities
Recent Advances in Enzymatic and Non-Enzymatic Electrochemical Glucose Sensing
Get PDFFrom MDPI via Jisc Publications RouterHistory: accepted 2021-07-06, pub-electronic 2021-07-08Publication status: PublishedFunder: Engineering and Physical Sciences Research Council; Grant(s): EP/R513131/1The detection of glucose is crucial in the management of diabetes and other medical conditions but also crucial in a wide range of industries such as food and beverages. The development of glucose sensors in the past century has allowed diabetic patients to effectively manage their disease and has saved lives. First-generation glucose sensors have considerable limitations in sensitivity and selectivity which has spurred the development of more advanced approaches for both the medical and industrial sectors. The wide range of application areas has resulted in a range of materials and fabrication techniques to produce novel glucose sensors that have higher sensitivity and selectivity, lower cost, and are simpler to use. A major focus has been on the development of enzymatic electrochemical sensors, typically using glucose oxidase. However, non-enzymatic approaches using direct electrochemistry of glucose on noble metals are now a viable approach in glucose biosensor design. This review discusses the mechanisms of electrochemical glucose sensing with a focus on the different generations of enzymatic-based sensors, their recent advances, and provides an overview of the next generation of non-enzymatic sensors. Advancements in manufacturing techniques and materials are key in propelling the field of glucose sensing, however, significant limitations remain which are highlighted in this review and requires addressing to obtain a more stable, sensitive, selective, cost efficient, and real-time glucose sensor
Some Information Geometric Aspects of Cyber Security by Face Recognition
Get PDFFrom MDPI via Jisc Publications RouterHistory: accepted 2021-06-29, pub-electronic 2021-07-09Publication status: PublishedSecure user access to devices and datasets is widely enabled by fingerprint or face recognition. Organization of the necessarily large secure digital object datasets, with objects having content that may consist of images, text, video or audio, involves efficient classification and feature retrieval processing. This usually will require multidimensional methods applicable to data that is represented through a family of probability distributions. Then information geometry is an appropriate context in which to provide for such analytic work, whether with maximum likelihood fitted distributions or empirical frequency distributions. The important provision is of a natural geometric measure structure on families of probability distributions by representing them as Riemannian manifolds. Then the distributions are points lying in this geometrical manifold, different features can be identified and dissimilarities computed, so that neighbourhoods of objects nearby a given example object can be constructed. This can reveal clustering and projections onto smaller eigen-subspaces which can make comparisons easier to interpret. Geodesic distances can be used as a natural dissimilarity metric applied over data described by probability distributions. Exploring this property, we propose a new face recognition method which scores dissimilarities between face images by multiplying geodesic distance approximations between 3-variate RGB Gaussians representative of colour face images, and also obtaining joint probabilities. The experimental results show that this new method is more successful in recognition rates than published comparative state-of-the-art methods
The Posthuman Trajectory of Isaac Asimov’s Foundation Universe
Get PDFWhen Isaac Asimov began to expand the fictional universe of his acclaimed Foundation Trilogy in 1982—almost thirty years after the publication of its prior entry, Second Foundation (1953)—he did so with the express intention of assimilating its continuity into a unified “history of the future” with his Robot and Galactic Empire series. Although the Foundation Universe has received little critical attention to date as a unified series, the analysis of it cumulatively reveals its significantly mundane and repetitive aspects. Demonstrably, the rhetorical function of such banal components renders the series conspicuously posthuman
Understanding the structural diversity of chitins as a versatile biomaterial
Get PDFFrom The Royal Society via Jisc Publications RouterHistory: accepted 2021-06-08, pub-electronic 2021-08-02, pub-print 2021-09-20Article version: VoRPublication status: PublishedChitin is one of the most abundant biopolymers, and it has adopted many different structural conformations using a combination of different natural processes like biopolymerization, crystallization and non-equilibrium self-assembly. This leads to a number of striking physical effects like complex light scattering and polarization as well as unique mechanical properties. In doing so, chitin uses a fine balance between the highly ordered chain conformations in the nanofibrils and random disordered structures. In this opinion piece, we discuss the structural hierarchy of chitin, its crystalline states and the natural biosynthesis processes to create such specific structures and diversity. Among the examples we explored, the unified question arises from the generation of completely different bioarchitectures like the Christmas tree-like nanostructures, gyroids or helicoidal geometries using similar dynamic non-equilibrium growth processes. Understanding the in vivo development of such structures from gene expressions, enzymatic activities as well as the chemical matrix employed in different stages of the biosynthesis will allow us to shift the material design paradigms. Certainly, the complexity of the biology requires a collaborative and multi-disciplinary research effort. For the future's advanced technologies, using chitin will ultimately drive many innovations and alternatives using biomimicry in materials science. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 1)'
The new cold war and the rise of the 21st‐century infrastructure state
Get PDFFrom Wiley via Jisc Publications RouterHistory: received 2020-03-07, rev-recd 2021-05-03, accepted 2021-06-14, pub-electronic 2021-08-02Article version: VoRPublication status: PublishedFunder: American Association of Geographers; Id: http://dx.doi.org/10.13039/100010262Funder: Association of Asian Studies, Chinese Academy of Sciences; Id: http://dx.doi.org/10.13039/501100002367Funder: University of Colorado Boulder; Id: http://dx.doi.org/10.13039/100007493Abstract: The unipolar international order led by the USA has given way to a multipolar order with the emergence of China as a great power competitor. According to many commentators, the deterioration of Sino–US relations in recent years heralds a “new Cold War.” The new Cold War differs from its namesake in many respects, and in this paper we focus on its novel territorial logic. Containing the USSR was the overriding objective of American foreign policy for nearly four decades, but in contrast, the USA and China are engaged in geopolitical‐economic competition to integrate territory into value chains anchored by their domestic lead firms through the financing and construction of transnational infrastructure (e.g., transportation networks and regional energy grids). We show this competition poses risks as well as opportunities for small states to articulate and realise spatial objectives. We present cases from Nepal and Laos that demonstrate that by hedging between China and the USA and its partners, their governments are able to pursue spatial objectives. In order to achieve them, however, they must implement significant reforms or state restructuring. The result is the emergence of what we term the 21st‐century infrastructure state, which seeks to mobilise foreign capital for infrastructure projects designed to enhance transnational connectivity
Regenerative Potential of Hydrogels for Intracerebral Hemorrhage: Lessons from Ischemic Stroke and Traumatic Brain Injury Research
Get PDFFrom Wiley via Jisc Publications RouterHistory: received 2021-03-09, rev-recd 2021-06-15, pub-electronic 2021-07-01Article version: VoRPublication status: PublishedFunder: Engineering and Physical Sciences Research Council; Id: http://dx.doi.org/10.13039/501100000266Funder: Medical Research Council; Id: http://dx.doi.org/10.13039/501100000265; Grant(s): EP/L014904/1Abstract: Intracerebral hemorrhage (ICH) is a deadly and debilitating type of stroke, caused by the rupture of cerebral blood vessels. To date, there are no restorative interventions approved for use in ICH patients, highlighting a critical unmet need. ICH shares some pathological features with other acute brain injuries such as ischemic stroke (IS) and traumatic brain injury (TBI), including the loss of brain tissue, disruption of the blood–brain barrier, and activation of a potent inflammatory response. New biomaterials such as hydrogels have been recently investigated for their therapeutic benefit in both experimental IS and TBI, owing to their provision of architectural support for damaged brain tissue and ability to deliver cellular and molecular therapies. Conversely, research on the use of hydrogels for ICH therapy is still in its infancy, with very few published reports investigating their therapeutic potential. Here, the published use of hydrogels in experimental ICH is commented upon and how approaches reported in the IS and TBI fields may be applied to ICH research to inform the design of future therapies is described. Unique aspects of ICH that are distinct from IS and TBI that should be considered when translating biomaterial‐based therapies between disease models are also highlighted
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