16,292 research outputs found

    DNA Logic-A novel approach to semiconductor based genetics

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    In the coming years, genetic test results will be increasingly used as indicators that influence medical decision-making. With chronic disease on the rise and the continuing global spread of infectious disease, novel instruments able to detect relevant mutations in a point-of-care setting are being developed to facilitate this increased demand in personalized health care. However, diagnosis for such demand often requires laboratory facilities and skilled personnel, meaning that diagnostic tests are restricted by time and access. This thesis presents a novel configuration for Ion sensitive Field Effect Transistors (ISFETs) to be used as a threshold detector during nucleic acid base pairs match. ISFET-based inverters are used as reaction threshold detectors to convey the chemical reaction level to a logic output once a threshold has been reached. Using this method, novel DNA logic functions are derived for nucleotides allowing local digital computations. The thesis also presents business models that enable such technology to be utilised in point of care applications, and experiment as results and business models given for an HIV point of care example are proposed

    Mass-spectrometric investigation of reaction of oxygen atoms with methane

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    Mass spectrometric investigation of oxygen atoms reacting with methan

    Secure Communications in Millimeter Wave Ad Hoc Networks

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    Wireless networks with directional antennas, like millimeter wave (mmWave) networks, have enhanced security. For a large-scale mmWave ad hoc network in which eavesdroppers are randomly located, however, eavesdroppers can still intercept the confidential messages, since they may reside in the signal beam. This paper explores the potential of physical layer security in mmWave ad hoc networks. Specifically, we characterize the impact of mmWave channel characteristics, random blockages, and antenna gains on the secrecy performance. For the special case of uniform linear array (ULA), a tractable approach is proposed to evaluate the average achievable secrecy rate. We also characterize the impact of artificial noise in such networks. Our results reveal that in the low transmit powerregime, the use of low mmWave frequency achieves better secrecy performance, and when increasing transmit power, a transition from low mmWave frequency to high mmWave frequency is demanded for obtaining a higher secrecy rate. More antennas at the transmitting nodes are needed to decrease the antenna gain obtained by the eavesdroppers when using ULA. Eavesdroppers can intercept more information by using a wide beam pattern. Furthermore, the use of artificial noise may be ineffective for enhancing the secrecy rate.Comment: Accepted by IEEE Transactions on Wireless Communication

    Interaction Between Ion Beams and Plasmas

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    Stability limits for ion acoustic waves due to interaction between low energy cesium ion beam and thermal cesium plasm

    A New Look at Physical Layer Security, Caching, and Wireless Energy Harvesting for Heterogeneous Ultra-dense Networks

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    Heterogeneous ultra-dense networks enable ultra-high data rates and ultra-low latency through the use of dense sub-6 GHz and millimeter wave (mmWave) small cells with different antenna configurations. Existing work has widely studied spectral and energy efficiency in such networks and shown that high spectral and energy efficiency can be achieved. This article investigates the benefits of heterogeneous ultra-dense network architecture from the perspectives of three promising technologies, i.e., physical layer security, caching, and wireless energy harvesting, and provides enthusiastic outlook towards application of these technologies in heterogeneous ultra-dense networks. Based on the rationale of each technology, opportunities and challenges are identified to advance the research in this emerging network.Comment: Accepted to appear in IEEE Communications Magazin

    Derivation of linearized transfer functions for switching-mode regulations. Phase A: Current step-up and voltage step-up converters

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    Small-signal models are derived for the power stage of the voltage step-up (boost) and the current step-up (buck) converters. The modeling covers operation in both the continuous-mmf mode and the discontinuous-mmf mode. The power stage in the regulated current step-up converter on board the Dynamics Explorer Satellite is used as an example to illustrate the procedures in obtaining the small-signal functions characterizing a regulated converter

    Electroproduction of the d* dibaryon

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    The unpolarized cross section for the electroproduction of the isoscalar Jπ=3+J^\pi = 3^+ di-delta dibaryon d∗d^* is calculated for deuteron target using a simple picture of elastic electron-baryon scattering from the ΔΔ(7D1)\Delta \Delta (^7D_1) and the NN(3S1)NN (^3S_1) components of the deuteron. The calculated differential cross section at the electron lab energy of 1 GeV has the value of about 0.24 (0.05) nb/sr at the lab angle of 10∘^\circ (30∘^\circ) for the Bonn B potential when the dibaryon mass is taken to be 2.1 GeV. The cross section decreases rapidly with increasing dibaryon mass. A large calculated width of 40 MeV for d∗(ΔΔ7S3)d^*(\Delta\Delta ^7S_3) combined with a small experimental upper bound of 0.08 MeV for the d∗d^* decay width appears to have excluded any low-mass d∗d^* model containing a significant admixture of the ΔΔ(7S3)\Delta\Delta (^7S_3) configuration.Comment: 11 journal-style pages, 8 figure

    Chronic Pancreatitis Progressing to Duodenal Obstruction in the Absence of Classic Symptoms

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    We report the case of a 34-year-old alcoholic who was initially seen in March 1985 because of acute pancreatitis. A mass was demonstrated in the head of the pancreas. Serial sonogram and computed tomography scans over 4 1/2 years revealed progressive encroachment of the duodenum without symptoms attributable to obstruction. In 1989, three separate endoscopies with multiple biopsies showed chronic inflammation and strictures. Hypotonic duodenography confirmed stricture and obstructed duodenum. Surgical intervention is being considered. Duodenal obstruction secondary to chronic pancreatitis is rare. It may proceed subclinically for several years independent of continued alcohol use. Only when obstruction became severe in our patient did the classic symptoms of postprandial nausea, emesis, and weight loss become manifest. Obstructive jaundice from chronic pancreatitis due to stricture in the pancreatic portion of the common bile duct is uncommon
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