648 research outputs found

    Mining Threat Intelligence about Open-Source Projects and Libraries from Code Repository Issues and Bug Reports

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    Open-Source Projects and Libraries are being used in software development while also bearing multiple security vulnerabilities. This use of third party ecosystem creates a new kind of attack surface for a product in development. An intelligent attacker can attack a product by exploiting one of the vulnerabilities present in linked projects and libraries. In this paper, we mine threat intelligence about open source projects and libraries from bugs and issues reported on public code repositories. We also track library and project dependencies for installed software on a client machine. We represent and store this threat intelligence, along with the software dependencies in a security knowledge graph. Security analysts and developers can then query and receive alerts from the knowledge graph if any threat intelligence is found about linked libraries and projects, utilized in their products

    Intermittent Theta Burst Stimulation: Application to Spinal Cord Injury Rehabilitation and Computational Modeling

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    Loss of motor function from spinal cord injuries (SCI) results in loss of independence. Rehabilitation efforts are targeted to enhance the ability to perform activities of daily living (ADLs), but outcomes from physical therapy alone are often insufficient. Neuromodulation techniques that induce neuroplasticity may push the limits on recovery. Neuromodulation by intermittent theta burst transcranial magnetic stimulation (iTBS) induces neuroplasticity by increasing corticomotor excitability, though this has most frequently been studied with motor targets and on individuals not in need of rehabilitation. Increased corticomotor excitability is associated with motor learning. The response to iTBS, however, is highly variable and unpredictable, while the mechanisms are not well understood. Studies have proposed brain anatomy and individual subject differences as a source of variability but have not quantified the effects. Existing models have not incorporated known neurotransmitter changes at the synaptic level to pair mechanisms to cell output in a neural circuit. To use iTBS in practical rehabilitative efforts, the technique must either be consistent, have a predictable responsiveness, or present with enough mechanistic understanding to improve its efficacy. To that effect, this study has two primary objectives for the improvement of rehabilitation techniques. The first is to establish how iTBS affects both a motor target and population that typically undergoes physical rehabilitation often with unsatisfactory outcomes, in this case the biceps brachii in individuals with SCI and relate the empirical effects of iTBS to individual anatomy. This will establish the consistency of the technique and predictability of its effects, relevant to rehabilitative efforts. The secondary objective is to create the foundation of a model that exhibits circuit organization, which would start the development of a motor neuroplasticity functional unit with simulation of the synaptic long-term potentiation (LTP) like effects of iTBS. Summary of Methods: iTBS was performed targeting the biceps, on multiple cohorts, with changes in motor evoked potential amplitude (MEP) tracked after sham and active intervention. This was compared between nonimpaired individuals and those with SCI. Furthermore, iTBS of both biceps and first dorsal interosseus (FDI) was compared to simulation of TMS on MRI derived head models to establish the impact of individualized neuroanatomy. Finally, a motor canonical neural circuit was programmed to display fundamental physiological spiking behavior of membrane potentials. Summary of Results: iTBS did facilitate corticomotor excitability in the biceps of nonimpaired individuals and in those with SCI. iTBS had no group-wide effect on the FDI, highlighting the variability in response to the protocol. TMS response (motor thresholds) and iTBS response (change in MEPs) both were related to parameters extracted from MRI-derived head models representing variations in individual neuroanatomy. The neural circuit model represents a canonical networked unit. In the future, this can be further tuned to exhibit biological variability and generate population-based values being run in parallel, while matching the understood mechanisms of neuroplasticity: disinhibition and LTP. Conclusion: These studies provide missing information of iTBS responsivity by (1) determining group-wide responsiveness in a clinically relevant target; (2) establishing individual level influences that affect responsivity which can be measured prior to iTBS; and (3) beginning design of a tool to test a single neural circuit and its mechanistic responses

    Model Driven Optimization of Drug Delivery for Spinal Cord Injury

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    Spinal cord injuries have an annual new case incidence in the United States of up to 40 cases per million population, with a 36.2% 10 year survival rate in patients over 50 years old. Barely half of survivors from 40 to 60 can perform activities of daily living, regardless of the severity of the initial injury. [1] Spinal cord injury is progressive, mediated by secondary injury, or a subacute inflammatory process that is poorly understood. [2-4] Secondary injury can involve or lead to apoptosis, scarring, cavitation, ischemia, and demyelination, among other sequelae, and many of these are not conducive to neuronal recovery. [4] Therefore there is a need for improved ways of addressing secondary injury mechanisms in these patients. [2] Minocycline can target multiple secondary injury mechanisms through its anti-inflammatory, anti-oxidative, and anti-apoptotic effects. [5-7] However, it is only fully effective at high concentrations. At the systemic levels required for this, minocycline can cause liver toxicity and even death. [8] Minocycline can form self-assembling, water insoluble particles with dextran sulfate and divalent metal cations, with high entrapment efficiency and a stable, slow release. There is potential for a controllable vehicle for drug delivery to optimize dosing with minocycline. [8] Predicting minocycline release behavior of a complex system can be performed by the creation of a model to simplify the system to an equation. This simplification can be guided by a combination of theoretical frameworks and previous empirical data that suggests idealized ratios between the components; previous work suggests the highest entrapment efficiency given a 1.2:1 mass concentration ratio of dextran sulfate:minocycline, in the presence of 7.2 mM Mg2+, suggesting saturation of binding sites at these values. [8] With a high degree of accuracy, this model can help direct the optimization of the drug delivery system. In the case of minocycline:dextran sulfate:Mg2+, the model proposed in this study was able to predict the trend of behavior but not with enough sensitivity for small dosing changes that characterize this delivery method. Biomedical engineering is an interdisciplinary field that combines understanding of various scientific and design expertise. In order to tailor a drug delivery system, as well as help to characterize the mechanism of release, generating a simple model can provide insight to the behavior of the system while reducing time, labor, and cost.M.S., Biomedical Engineering -- Drexel University, 201

    Optical quality ZnSe films and low loss waveguides on Si substrates for mid-infrared applications

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    Zinc Selenide (ZnSe) is a promising mid-infrared waveguide material with high refractive index and wide transparency. Optical quality ZnSe thin films were deposited on silicon substrates by RF sputtering and thermal evaporation, and characterized and compared for material and optical properties. Evaporated films were found to be denser and smoother than sputtered films. Rib waveguides were fabricated from these films and evaporated films exhibited losses as low as 0.6 dB/cm at wavelengths between 2.5 µm and 3.7 µm. The films were also used as isolation/lower cladding layers on Si with GeTe4 as the waveguide core and propagation losses were determined in this wavelength range

    Cardiac rehabilitation to improve health-related quality of life following trans-catheter aortic valve implantation: a randomised controlled feasibility study: RECOVER-TAVI Pilot, ORCA 4, for the Optimal Restoration of Cardiac Activity Group

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    Objectives: Transcatheter aortic valve implantation (TAVI) is often undertaken in the oldest frailest cohort of patients undergoing cardiac interventions. We plan to investigate the potential benefit of cardiac rehabilitation (CR) in this vulnerable population. Design: We undertook a pilot randomised trial of CR following TAVI to inform the feasibility and design of a future randomised clinical trial (RCT). Participants: We screened patients undergoing TAVI at a single institution between June 2016 and February 2017. Interventions: Participants were randomised post-TAVI to standard of care (control group) or standard of care plus exercise-based CR (intervention group). Outcomes: We assessed recruitment and attrition rates, uptake of CR, and explored changes in 6-min walk test, Nottingham Activities of Daily Living, Fried and Edmonton Frailty scores and Hospital Anxiety and Depression Score, from baseline (30 days post TAVI) to 3 and 6 months post randomisation. We also undertook a parallel study to assess the use of the Kansas City Cardiomyopathy Questionnaire (KCCQ) in the post-TAVI population. Results: Of 82 patients screened, 52 met the inclusion criteria and 27 were recruited (3 patients/month). In the intervention group, 10/13 (77%) completed the prescribed course of 6 sessions of CR (mean number of sessions attended 7.5, SD 4.25) over 6 weeks. At 6 months, all participants were retained for follow-up. There was apparent improvement in outcome scores at 3 and 6 months in control and CR groups. There were no recorded adverse events associated with the intervention of CR. The KCCQ was well accepted in 38 post-TAVI patients: mean summary score 72.6 (SD 22.6). Conclusions: We have demonstrated the feasibility of recruiting post-TAVI patients into a randomised trial of CR. We will use the findings of this pilot trial to design a fully powered multicentre RCT to inform the provision of CR and support guideline development to optimise health-related quality of life outcomes in this vulnerable population. Retrospectively registered 3rd October 2016 clinicaltrials.gov NCT02921880. Trial registration: Clinicaltrials.Gov identifier NCT0292188

    Screening for adulticidal bioactivity of South African plants against Anopheles arabiensis

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    <p>Abstract</p> <p>Background</p> <p>This study was conducted to evaluate whether a selection of South African ethnomedicinal plants included in this study displayed insecticidal properties when screened against adult stages of the mosquito.</p> <p>Methods</p> <p>381 crude extracts of 80 plant taxa in 42 families were sprayed onto ceramic tiles and screened using the cone bio-assay method for insecticide efficacy testing. Blood-fed, female <it>Anopheles arabiensis </it>mosquitoes were exposed to the treated tiles for a period of sixty minutes. Mosquito mortality was monitored for twenty-four hours.</p> <p>Results</p> <p>Of all the extracts analysed, the highest activity was observed in <it>Ptaeroxylon obliquum </it>(Ptaeroxylaceae) and <it>Pittosporum viridiflorum </it>(Pittosporaceae), a single extract from each, exhibiting more than 50% mortality. A large proportion (81.63%) of the extracts tested displayed low levels of mosquitocidal activity. The remainder of the extracts (17.85%) exhibited no bioactivity (0% mortality).</p> <p>Conclusions</p> <p>The screening results have shown that in accordance with WHO standards, none of the crude extracts tested had exhibited greater than 60% mortality against the adult stages of the malaria vector <it>Anopheles arabiensis</it>.</p
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