1,560 research outputs found

    Decay and coherence of two-photon excited yellow ortho-excitons in Cu2O

    Get PDF
    Photoluminescence excitation spectroscopy has revealed a novel, highly efficient two-photon excitation method to produce a cold, uniformly distributed high density excitonic gas in bulk cuprous oxide. A study of the time evolution of the density, temperature and chemical potential of the exciton gas shows that the so called quantum saturation effect that prevents Bose-Einstein condensation of the ortho-exciton gas originates from an unfavorable ratio between the cooling and recombination rates. Oscillations observed in the temporal decay of the ortho-excitonic luminescence intensity are discussed in terms of polaritonic beating. We present the semiclassical description of polaritonic oscillations in linear and non-linear optical processes.Comment: 14 pages, 12 figure

    Land Cover Mapping Using High Spatial Resolution SPOT Data Over Penang Island Malaysia.

    Get PDF
    Satellite digital imagery has proved to be an effective tool for land cover changes studies. The objective of this study is to demonstrate the effectiveness of SPOT imageries in changes detection over Penang Island, Malaysia. An understanding of land use/land cover at local with high resolution is important to prepare the latest data and can be used in many purposes. The neural network classifier was performed to the satellite images and the results were compared with four standard supervised classification techniques, such as the maximum likelihood, minimum distance-to-mean and parallelepiped

    Characterisation of a highly potent and near pan-neutralising anti-HIV monoclonal antibody expressed in tobacco plants

    Get PDF
    Background HIV remains one of the most important health issues worldwide, with almost 40 million people living with HIV. Although patients develop antibodies against the virus, its high mutation rate allows evasion of immune responses. Some patients, however, produce antibodies that are able to bind to, and neutralise different strains of HIV. One such ‘broadly neutralising’ antibody is ‘N6’. Identified in 2016, N6 can neutralise 98% of HIV-1 isolates with a median IC50 of 0.066 µg/mL. This neutralisation breadth makes N6 a very promising therapeutic candidate. Results N6 was expressed in a glycoengineered line of N. benthamiana plants (pN6) and compared to the mammalian cell-expressed equivalent (mN6). Expression at 49 mg/kg (fresh leaf tissue) was achieved in plants, although extraction and purification are more challenging than for most plant-expressed antibodies. N-glycoanalysis demonstrated the absence of xylosylation and a reduction in α(1,3)-fucosylation that are typically found in plant glycoproteins. The N6 light chain contains a potential N-glycosylation site, which was modified and displayed more α(1,3)-fucose than the heavy chain. The binding kinetics of pN6 and mN6, measured by surface plasmon resonance, were similar for HIV gp120. pN6 had a tenfold higher affinity for FcγRIIIa, which was reflected in an antibody-dependent cellular cytotoxicity assay, where pN6 induced a more potent response from effector cells than that of mN6. pN6 demonstrated the same potency and breadth of neutralisation as mN6, against a panel of HIV strains. Conclusions The successful expression of N6 in tobacco supports the prospect of developing a low-cost, low-tech production platform for a monoclonal antibody cocktail to control HIV in low-to middle income countries

    A techno-economical and automotive emissions impact study of global biodiesel usage in diesel engines

    Get PDF
    In recent years, biodiesel has arrived at the forefront, as a mainstream alternative energy, due to its advantages properties such as renewability, compatibility with existing automotive infrastructures and diesel engines, cleaner emissions. Many studies have been conducted to improve the maturity of biodiesel production technology, and fuel application. However, the global-scale economical and emissions impacts of first generation biodiesel is still not being adequately addressed. This requires immediate attention as the current economical setback for biodiesel is affected by low crude oil price. In this study, the correlations between the biodiesel production feasibility, crude oil price, and feedstock availability are defined. By using a data-driven predictive model, insights can be drawn for the worldwide profitability, potential level of diesel replacement using biodiesel, and environmental impact. The model allows prediction to be done on potential biodiesel production at a country-region level, at different crude oil prices and fuel blending ratios. It was also predicted that up to 9% of total global diesel consumption could be replaced by profitable biodiesel, if crude oil price rises up to USD 135 per barrel and factoring in refinery cost of USD 0.05 per litre. Countries near the equatorial belt with abundance palm oil feedstock such as Malaysia, Papua New Guinea and Indonesia could potentially augment their gross domestic products by 10.36%, 7.67% and 5.57%, respectively. If all non-domestic usage feedstock is converted into biodiesel for automotive usage, there will be conclusive reduction of engine-out emissions such as unburnt hydrocarbons and particulate matter. Ultimately, this model proves that there is high potential for mass adoption of biodiesel to supplant fossil diesel globally, allowing the generation of income, improving energy security and produces cleaner automotive emissions

    Predictive biometrics: A review and analysis of predicting personal characteristics from biometric data

    Get PDF
    Interest in the exploitation of soft biometrics information has continued to develop over the last decade or so. In comparison with traditional biometrics, which focuses principally on person identification, the idea of soft biometrics processing is to study the utilisation of more general information regarding a system user, which is not necessarily unique. There are increasing indications that this type of data will have great value in providing complementary information for user authentication. However, the authors have also seen a growing interest in broadening the predictive capabilities of biometric data, encompassing both easily definable characteristics such as subject age and, most recently, `higher level' characteristics such as emotional or mental states. This study will present a selective review of the predictive capabilities, in the widest sense, of biometric data processing, providing an analysis of the key issues still adequately to be addressed if this concept of predictive biometrics is to be fully exploited in the future

    Engineering Secretory IgA against Infectious Diseases

    Get PDF
    The dawn of antibody therapy was heralded by the rise of IgG therapeutics. However, other antibody classes are at our disposal—one of the most exciting is IgA and is the most abundant antibody class within humans. Unlike IgG, it is uniquely specialized for mucosal applications due to its ability to form complex Secretory IgA (SIgA) molecules. Since the mucosa is constantly exposed to potential infectious agents, SIgA is pivotal to disease prevention as an important component of the mucosal barrier. Compared to IgG, SIgA has proven superior effectiveness in mucosal surfaces, such as the airway epithelium or the harsh gut environment. Despite this, hurdles associated with low yield and challenging purification have blocked SIgA therapeutic advancement. However, as a result of new antibody engineering strategies, we are approaching the next generation of (IgA-based) antibody therapies. Strategies include fine-tuning SIgA assembly, exploring different production platforms, genetic engineering to improve purification, and glycoengineering of different components. Due to its stability in mucosal environments, SIgA therapeutics would revolutionize passive mucosal immunotherapy—an avenue still underexploited by current therapeutics. This chapter will focus on the current perspectives of SIgA engineering and explore different approaches to unlocking the full therapeutic potential of SIgAs

    Termites mitigate the effects of drought in tropical rainforest

    Get PDF
    Acknowledgments: This work was supported by the South East Asia Rainforest Research Partnership (SEARRP) with permission from the Maliau Basin Management Committee. We thank G. Reynolds, U. Jami, and L. Kruitbos for coordinating fieldwork; S. Both and U. Kritzler for help in establishing the experimental plots; R. Walsh for providing rainfall data; and A. Zanne and A. Cheesman for discussions on experimental design. We thank J. Nash from Bayer Southeast Asia Pte-Ltd, Singapore, for donating Premise 200SC and Agenda 10SC. We thank J. Rees, A. Tagliabue, M. Begon, R. Williams, W. Cheng, C. Dahlsjö, R. Kitching, and J. Barlow for comments on the manuscript. Finally, we thank all our field assistants: R. Binti Manber, A. Jupri, F. John, Y. Binti Suffian, E. Bin Esing, D. Bin Paul, Z. Bin Angau, A. Allbanah Bin Anchun, N. Angau, D. Ku Shamirah Binti Pg Bakar, E. Binti Nahun, R. Rusili, A. Bin Rantau, R. Bin Sahamin, A. Mastor, M. Adzim Bin Rahili, M. Azuan, H. Nasir, and N. Fazzli. Funding: This publication is a contribution from the UK NERC-funded Biodiversity And Land-use Impacts on Tropical Ecosystem Function (BALI) consortium (NERC grant NE/L000016/1). Author contributions: C.L.P., H.M.G., L.A.A., P.E., and T.A.E. conceived and designed the experiment; C.L.P., P.E., and T.A.E. established the experimental plots; H.M.G., L.A.A., and P.E. collected the data; H.M.G., L.A.A., P.E., and R.K.D. analyzed the data; C.S.V., F.H., and H.S.T. carried out laboratory analysis; H.M.G. and L.A.A. led the writing of the manuscript with significant input from C.L.P., P.E., R.K.D., and Y.A.T. Competing interests: None declared. Data and materials availability: Data have been deposited in the NERC Environmental Information Data Centre (37).Peer reviewedPostprin

    Targeting 1.5 degrees with the global carbon footprint of the Australian Capital Territory

    Full text link
    In 2019 the Australian Capital Territory (ACT) government stated an ambition to prioritise reduction of Scope 3 greenhouse gas emissions, the size of which had not been fully quantified previously. This study calculated the total carbon footprint of the ACT in 2018, including Scope 1, 2 and 3 emissions and modelled scenarios to reduce all emissions in line with a 1.5 °C target approach. This is the first time a multi-scale analysis of local, sub-national and international supply chains has been undertaken for a city, using a nested and trade-adjusted global multi-region input-output model. This allowed for the quantification of global origins and destinations of emissions, which showed that the 2018 carbon footprint for the ACT was approximately 34.7 t CO2-eq/cap, with 83% attributed to Scope 3. Main contributions came from transport, electricity, manufacturing and public administration and safety, with emissions generated primarily in Australian States and Territories. Modelling in accordance with a 1.5 °C warming scenario showed a plausible reduction to 5.2 t CO2-eq/cap by 2045 (excluding offsets or carbon dioxide removal technologies), with remaining emissions predominantly embodied in international supply chains. This study demonstrates the radical changes required by a wealthy Australian city to achieve 1.5 °C compliance and identifies sectors and supply chains for prioritising policies to best achieve this outcome

    (2E)-1-(2-Bromo­phen­yl)-3-(4-chloro­phen­yl)prop-2-en-1-one

    Get PDF
    In the title compound, C15H10BrClO, the dihedral angle between the mean planes of the benzene rings in the ortho-bromo- and para-chloro-substituted rings is 70.5 (6)°. The dihedral angles between the mean plane of the prop-2-en-1-one group and the mean planes of the benzene rings in the 4-chloro­phenyl and 2-bromo­phenyl rings are 14.9 (3) and 63.3 (8)°, respectively. In the crystal, inversion dimers linked by pairs of weak C—H⋯O interactions are observed as well as aromatic π–π stacking inter­actions
    corecore