1,744 research outputs found

    Secure and Trustable Electronic Medical Records Sharing using Blockchain

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    Electronic medical records (EMRs) are critical, highly sensitive private information in healthcare, and need to be frequently shared among peers. Blockchain provides a shared, immutable and transparent history of all the transactions to build applications with trust, accountability and transparency. This provides a unique opportunity to develop a secure and trustable EMR data management and sharing system using blockchain. In this paper, we present our perspectives on blockchain based healthcare data management, in particular, for EMR data sharing between healthcare providers and for research studies. We propose a framework on managing and sharing EMR data for cancer patient care. In collaboration with Stony Brook University Hospital, we implemented our framework in a prototype that ensures privacy, security, availability, and fine-grained access control over EMR data. The proposed work can significantly reduce the turnaround time for EMR sharing, improve decision making for medical care, and reduce the overall costComment: AMIA 2017 Annual Symposium Proceeding

    Thermotaxis in Caenorhabditis elegans analyzed by measuring responses to defined thermal stimuli

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    In a spatial thermal gradient, Caenorhabditis elegans migrates toward and then isothermally tracks near its cultivation temperature. A current model for thermotactic behavior involves a thermophilic drive (involving the neurons AFD and AIY) and cryophilic drive (involving the neuron AIZ) that balance at the cultivation temperature. Here, we analyze the movements of individual worms responding to defined thermal gradients. We found evidence for a mechanism for migration down thermal gradients that is active at temperatures above the cultivation temperature, and a mechanism for isothermal tracking that is active near the cultivation temperature. However, we found no evidence for a mechanism for migration up thermal gradients at temperatures below the cultivation temperature that might have supported the model of opposing drives. The mechanisms for migration down gradients and isothermal tracking control the worm's movements in different manners. Migration down gradients works by shortening (lengthening) the duration of forward movement in response to positive (negative) temperature changes. Isothermal tracking works by orienting persistent forward movement to offset temperature changes. We believe preference for the cultivation temperature is not at the balance between two drives. Instead, the worm activates the mechanism for isothermal tracking near the cultivation temperature and inactivates the mechanism for migration down gradients near or below the cultivation temperature. Inactivation of the mechanism for migration down gradients near or below the cultivation temperature requires the neurons AFD and AIY

    Mechanism for CCC DNA Synthesis in Hepadnaviruses

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    Hepadnavirus replication requires the synthesis of a covalently closed circular (CCC) DNA from the relaxed circular (RC) viral genome by an unknown mechanism. CCC DNA formation could require enzymatic activities of the viral reverse transcriptase (RT), or cellular DNA repair enzymes, or both. Physical mapping of the 5′ and 3′ ends of RC DNA and sequence analysis of CCC DNA revealed that CCC DNA synthesis requires the removal of the RT and an RNA oligomer from the 5′ ends of minus and plus strand DNA, respectively, removal of sequences from the terminally redundant minus strand, completion of the less than full-length plus strand, and ligation of the ends. Two models have been proposed that could explain CCC DNA formation. The first (model 1) invokes a role for the RT to catalyze a cleavage-ligation reaction leading to the formation of a unit length minus strand in CCC DNA and a DNA repair reaction for the completion and ligation of plus strand DNA; the second (model 2) predicts that CCC DNA formation depends entirely on cellular DNA repair enzymes. To determine which mechanism is utilized, we developed cell lines expressing duck hepatitis B virus genomes carrying mutations permitting us to follow the fate of viral DNA sequences during their conversion from RC to CCC DNA. Our results demonstrated that the oligomer at the 5′ end of minus strand DNA is completely or at least partially removed prior to CCC DNA synthesis. The results indicated that both RC DNA strands undergo DNA repair reactions carried out by the cellular DNA repair machinery as predicted by model 2. Thus, our study provided the basis for the identification of the cellular components required for CCC DNA formation

    Steps in the bacterial flagellar motor

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    The bacterial flagellar motor is a highly efficient rotary machine used by many bacteria to propel themselves. It has recently been shown that at low speeds its rotation proceeds in steps [Sowa et al. (2005) Nature 437, 916--919]. Here we propose a simple physical model that accounts for this stepping behavior as a random walk in a tilted corrugated potential that combines torque and contact forces. We argue that the absolute angular position of the rotor is crucial for understanding step properties, and show this hypothesis to be consistent with the available data, in particular the observation that backward steps are smaller on average than forward steps. Our model also predicts a sublinear torque-speed relationship at low torque, and a peak in rotor diffusion as a function of torque

    Turbulent Magnetic Field Amplification from Spiral SASI Modes: Implications for Core-Collapse Supernovae and Proto-Neutron Star Magnetization

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    We extend our investigation of magnetic field evolution in three-dimensional flows driven by the stationary accretion shock instability (SASI) with a suite of higher-resolution idealized models of the post-bounce core-collapse supernova environment. Our magnetohydrodynamic simulations vary in initial magnetic field strength, rotation rate, and grid resolution. Vigorous SASI-driven turbulence inside the shock amplifies magnetic fields exponentially; but while the amplified fields reduce the kinetic energy of small-scale flows, they do not seem to affect the global shock dynamics. The growth rate and final magnitude of the magnetic energy are very sensitive to grid resolution, and both are underestimated by the simulations. Nevertheless our simulations suggest that neutron star magnetic fields exceeding 101410^{14} G can result from dynamics driven by the SASI, \emph{even for non-rotating progenitors}.Comment: 28 pages, 17 figures, accepted for publication in the Ap

    The Properties of X-ray Cold Fronts in a Statistical Sample of Simulated Galaxy Clusters

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    We examine the incidence of cold fronts in a large sample of galaxy clusters extracted from a (512h^-1 Mpc) hydrodynamic/N-body cosmological simulation with adiabatic gas physics computed with the Enzo adaptive mesh refinement code. This simulation contains a sample of roughly 4000 galaxy clusters with M > 10^14 M_sun at z=0. For each simulated galaxy cluster, we have created mock 0.3-8.0 keV X-ray observations and spectroscopic-like temperature maps. We have searched these maps with a new automated algorithm to identify the presence of cold fronts in projection. Using a threshold of a minimum of 10 cold front pixels in our images, corresponding to a total comoving length L_cf > 156h^-1 kpc, we find that roughly 10-12% of all projections in a mass-limited sample would be classified as cold front clusters. Interestingly, the fraction of clusters with extended cold front features in our synthetic maps of a mass-limited sample trends only weakly with redshift out to z=1.0. However, when using different selection functions, including a simulated flux limit, the trending with redshift changes significantly. The likelihood of finding cold fronts in the simulated clusters in our sample is a strong function of cluster mass. In clusters with M>7.5x10^14 M_sun the cold front fraction is 40-50%. We also show that the presence of cold fronts is strongly correlated with disturbed morphology as measured by quantitative structure measures. Finally, we find that the incidence of cold fronts in the simulated cluster images is strongly dependent on baryonic physics.Comment: 16 pages, 21 figures, Accepted to Ap

    Potential alternative treatment approach for pediatric patient with diffusely infiltrative primary rhabdomyosarcoma of the liver

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    Primary hepatic rhabdomyosarcoma is rare, making decisions regarding locoregional management with resection and/or conventional radiation difficult. We present a novel treatment approach for a pediatric patient diagnosed with rhabdomyosarcoma diffusely involving the liver. This patient underwent treatment with yttrium-90 (Y-90) microspheres followed by external beam radiation therapy (EBRT) to residual disease, interdigitated with systemic chemotherapy. Initial post-radiation imaging showed significant response to treatment, and she experienced minimal acute toxicities and no long-term toxicities. She developed recurrent PET-avid disease 23 months after Y-90 treatment, necessitating further local and continued systemic therapies. We report on the tumor control following Y-90 and EBRT treatment

    ACR Appropriateness Criteria® Non-Spine Bone Metastases

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    Bone metastases are a common clinical problem, affecting many types of cancer patients. The presence of tumor in bone can cause significant morbidity including pain, neurological dysfunction, hypercalcemia, and pathological fracture leading to functional loss. The optimal treatment of a patient with bone metastases depends on many factors, including evaluation of the patient's goals of care, performance status, mechanical stability of the affected bone, life expectancy, and overall extent of disease. Treatment options may include radiotherapy, systemic therapies, surgical stabilization, medical pain management, and radiopharmaceuticals. Ideal management of bone metastases requires a coordinated multidisciplinary approach among diagnostic radiologists, radiation oncologists, medical oncologists, orthopedic surgeons, pain specialists, physiatrists, and palliative care specialists. The American College of Radiology Appropriateness Criteria? are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guidelines development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140118/1/jpm.2014.9395.pd

    ACR Appropriateness Criteria® Spinal Bone Metastases

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    The spine is a common site of involvement in patients with bone metastases. Apart from pain, hypercalcemia, and pathologic fracture, progressive tumor can result in neurologic deterioration caused by spinal cord compression or cauda equina involvement. The treatment of spinal bone metastases depends on histology, site of disease, extent of epidural disease, extent of metastases elsewhere, and neurologic status. Treatment recommendations must weigh the risk-benefit profile of external beam radiation therapy (EBRT) for the particular individual's circumstance, including neurologic status, performance status, extent of spinal disease, stability of the spine, extra-spinal disease status, and life expectancy. Patients with spinal instability should be evaluated for surgical intervention. Research studies are needed that evaluate the combination or sequencing of localized therapies with systemic therapies including chemotherapy, hormonal therapy (HT), osteoclast inhibitors (OI), and radiopharmaceuticals. The roles of stereotactic body radiation therapy (SBRT) in the management of spinal oligometastasis, radioresistant spinal metastasis, and previously irradiated but progressive spinal metastasis are emerging, but more research is needed to validate the findings from retrospective studies. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140115/1/jpm.2012.0376.pd

    Exotic quantum holonomy induced by degeneracy hidden in complex parameter space

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    An adiabatic change of a bound state along a closed circuit in the parameter space can induces holonomies not only in the phase of the state, but also in the associated eigenspace and eigenvalue. The former is the well-known Berry phase while the latter, namely the exotic holonomy, is found a decade ago and its origin has not been understood yet. By extending the parameter into the complex number, the correspondence of the exotic holonomies and the degeneracy of the non-Hermitian Hamiltonian, or the exceptional points, is revealed. We show that this explains all the known non-trivial characteristics of the exotic holonomies.Comment: 4 pages, 1 figur
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