495 research outputs found

    RAPTOR: Routing Attacks on Privacy in Tor

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    The Tor network is a widely used system for anonymous communication. However, Tor is known to be vulnerable to attackers who can observe traffic at both ends of the communication path. In this paper, we show that prior attacks are just the tip of the iceberg. We present a suite of new attacks, called Raptor, that can be launched by Autonomous Systems (ASes) to compromise user anonymity. First, AS-level adversaries can exploit the asymmetric nature of Internet routing to increase the chance of observing at least one direction of user traffic at both ends of the communication. Second, AS-level adversaries can exploit natural churn in Internet routing to lie on the BGP paths for more users over time. Third, strategic adversaries can manipulate Internet routing via BGP hijacks (to discover the users using specific Tor guard nodes) and interceptions (to perform traffic analysis). We demonstrate the feasibility of Raptor attacks by analyzing historical BGP data and Traceroute data as well as performing real-world attacks on the live Tor network, while ensuring that we do not harm real users. In addition, we outline the design of two monitoring frameworks to counter these attacks: BGP monitoring to detect control-plane attacks, and Traceroute monitoring to detect data-plane anomalies. Overall, our work motivates the design of anonymity systems that are aware of the dynamics of Internet routing

    Impact of multimorbidity count on all-cause mortality and glycaemic outcomes in people with type 2 diabetes: a systematic review protocol

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    Introduction: Type 2 diabetes (T2D) is a leading health priority worldwide. Multimorbidity (MM) is a term describing the co-occurrence of two or more chronic diseases or conditions. The majority of people living with T2D have MM. The relationship between MM and mortality and glycaemia in people with T2D is not clear. Methods and analysis: Medline, Embase, Cumulative Index of Nursing and Allied Health Complete, The Cochrane Library, and SCOPUS will be searched with a prespecified search strategy. The searches will be limited to quantitative empirical studies in English with no restriction on publication date. One reviewer will perform title screening and two review authors will independently screen the abstract and full texts using Covidence software, with disagreements adjudicated by a third reviewer. Data will be extracted using a using a Population, Exposure, Comparator and Outcomes framework. Two reviewers will independently extract data and undertake the risk of bias (quality) assessment. Disagreements will be resolved by consensus. A narrative synthesis of the results will be conducted and meta-analysis considered if appropriate. Quality appraisal will be undertaken using the Newcastle-Ottawa quality assessment scale and the quality of the cumulative evidence of the included studies will be assessed using the Grading of Recommendations, Assessment, Development and Evaluation approach. This protocol was prepared in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines to ensure the quality of our review. Ethics and dissemination: This review will synthesise the existing evidence about the impact of MM on mortality and glycaemic outcomes in people living with T2D and increase our understanding of this subject and will inform future practice and policy. Findings will be disseminated via conference presentations, social media and peer-reviewed publication

    Modulating carbohydrate–protein interactions through glycoengineering of monoclonal antibodies to impact cancer physiology

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    Diverse glycans on proteins help impact cell and organism physiology along with drug activity. Since many protein-based biotherapeutics are glycosylated and these glycans have biological activity, there is a desire to engineer glycosylation for recombinant protein-based biotherapeutics. Engineered glycosylation can impact the recombinant protein efficacy and also influence many cell pathways by first changing glycan-protein interactions and consequently modulating disease physiologies. However, its complexity is enormous. Due to recent advances in glycoengineering, modulating protein-glycan interactions become more amenable to therapeutic approaches. Here, we discuss how engineered glycans contribute to therapeutic monoclonal antibodies (mAbs) in the treatment of cancers, how these glycoengineered therapeutic mAbs affect the transformed phenotypes and downstream cell pathways, and how systems biology can help in the next generation mAb glycoengineering process by aiding in data analysis and guiding engineering efforts to tailor mAb glycan and ultimately drug efficacy, safety and affordability

    Gas adsorption and capillary condensation in nanoporous alumina films

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    "Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation."http://deepblue.lib.umich.edu/bitstream/2027.42/64187/1/nano8_31_315709.pd

    Light-induced translation of motorized molecules on a surface

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    Molecular machines are a key component in the vision of molecular nanotechnology and have the potential to transport molecular species and cargo on surfaces. The motion of such machines should be triggered remotely, ultimately allowing a large number of molecules to be propelled by a single source, with light being an attractive stimulus. Here, we report upon the photoinduced translation of molecular machines across a surface by characterizing single molecules before and after illumination. Illumination of molecules containing a motor unit results in an enhancement in the diffusion of the molecules. The effect vanishes if an incompatible photon energy is used or if the motor unit is removed from the molecule, revealing that the enhanced motion is due to the presence of the wavelength-sensitive motor in each molecule

    Is rat a good model for assessment of particulate-based taste-masked formulations?

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    Recently there has been an increased interest to develop specialised dosage forms that are better suited to specific patient populations, such as paediatrics and geriatrics. In these patient populations the acceptability of the oral dosage form can be paramount to the products success. However, many active pharmaceutical Ingredients (APIs) are known to cause an aversive taste response. One way to increase the acceptability and to enhance the palatability of the formulation is to design coated taste-masked particulate-based dosage forms. The masking of poorly tasting drugs with physical barriers such as polymer coatings can be utilised to prevent the release of drug within the oral cavity, thus preventing a taste response. However, currently, there are few assessment tools and models available to test the efficiency of these particulate-based taste-masked formulations. The rat brief access taste aversion model has been shown to be useful in assessment of taste for liquid dosage forms. However, the applicability of the rat model for particulate-based taste masked formulations is yet to be assessed. It is not understood whether dissolution, solubility and thus exposure of the drug to taste receptors would be the same in rat and human. Therefore, rat saliva must be compared to human saliva to determine the likelihood that drug release would be similar within the oral cavity for both species. In this study rat saliva was characterised for parameters known to be important for drug dissolution, such as pH, buffer capacity, surface tension, and viscosity. Subsequently dissolution of model bitter tasting compounds, sildenafil citrate and efavirenz, in rat saliva was compared to dissolution in human saliva. For all parameters characterised and for the dissolution of both drugs in rat saliva, a substantial difference was observed when compared to human saliva. This discrepancy in saliva parameters and dissolution of model drugs suggests that preclinical taste evaluation of particulate-based taste-masked formulations suggests rat is not a good model for predicting taste of solid dosage forms or undissolved drug where dissolution is required. Alternative preclinical in vivo models in other species, or improved biorelevant in vitro models should be considered instead

    Type 1 Diabetes Through the Life Span: A Position Statement of the American Diabetes Association

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    Type 1 diabetes is characterized by an immune-mediated depletion of ÎČ-cells that results in lifelong dependence on exogenous insulin. While both type 1 and type 2 diabetes result in hyperglycemia, the pathophysiology and etiology of the diseases are distinct and require us to consider each type of diabetes independently. As such, this position statement summarizes available data specific to the comprehensive care of individuals with type 1 diabetes. The goal is to enhance our ability to recognize and manage type 1 diabetes, to prevent its associated complications, and to eventually cure and prevent this disease. The exact number of individuals with type 1 diabetes around the world is not known, but in the U.S., there are estimated to be up to 3 million (1). Although it has long been called “juvenile diabetes” due to the more frequent and relatively straightforward diagnosis in children, the majority of individuals with type 1 diabetes are adults. Most children are referred and treated in tertiary centers, where clinical data are more readily captured. The SEARCH for Diabetes in Youth study estimated that, in 2009, 18,436 U.S. youth were newly diagnosed with type 1 diabetes (12,945 non-Hispanic white, 3,098 Hispanic, 2,070 non-Hispanic black, 276 Asian-Pacific Islander, and 47 American Indian) (2). Worldwide, ∌78,000 youth are diagnosed with type 1 diabetes annually. Incidence varies tremendously among countries: East Asians and American Indians have the lowest incidence rates (0.1–8 per 100,000/year) as compared with the Finnish who have the highest rates (>64.2 per 100,000/year) (3). In the U.S., the number of youth with type 1 diabetes was estimated to be 166,984 (4). The precise incidence of new-onset type 1 diabetes in those over 20 years of age is unknown. This may be due to the prolonged phase of onset and the subtleties in distinguishing the different
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