1,628 research outputs found

    A Study on Solitary Nodule of the Thyroid

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    BACKGROUND AND OBJECTIVES: Solitary nodule of the thyroid of discrete thyroid swelling is a common clinical entity and the incidence increases with age. About half of the patients with palpable nodular goitre are diagnosed as multinodular goitre. The importance of this clinical entity is that 10-20% of solitary nodules of the thyroid could be malignant. The approach to thyroid nodule management is a selective one, utilizing continually Improving diagnostic techniques to reliably identify patients with malignancy and certain benign conditions that require surgery thereby avoiding unnecessary thyroidectomy for all nodules. A potentially curable cancer normally presents as a thyroid nodule and thereby the study of a solitary nodule gains importance. The main objectives of this study is To find the epidemiology,role of fine needle aspiration cytology &The incidence of malignancy in solitary nodule of the thyroid. METHODS: All patients admitted with a solitary nodule of the thyroid. Excluding Patients with severe comorbid illness and those with regional lymph adenopathy. A total of 100 consecutive patients with solitary nodule of the thyroid admitted were evaluated clinically, biochemically, radiologically and cytologically. The patients underwent Hyemithyroidectomy and the histopathology of the excised specimens were studied to evaluate the incidence of malignancy. RESULTS: Solitary nodule of the thyroids are common in third decade of life, females are more commonly affected than male, incidence of maligancy found to be more common in male who where in age group from 21 – 50yrs. Most common clinical symptoms swelling and most common post operative complication is hypothyroidism seen in 10% of cases. Retrospective comparison with Histopathology of excised specimen revealed a false negative report in FNAC in detecting malignancy in 16 cases of malignant nodules. CONCLUSION: Solitary nodule of the thyroid was found to be more common in young and middle aged patients. AMONG WHICH IT IS 8 times more common in females than males. Majority of the solitary nodule were dominant nodules of a multinodular goiter. In the individuals admitted with solitary nodule of thyroid and managed by hemithyroidectomy, the incidence of malignancy was 16%. Fine needle aspiration cytology, now considered as the gold standard diagnostic test in the evaluation of a thyroid nodule revealed false negative report in 16 patients in this study. Ultra sonogram and nuclear scans are also useful tests, but are best used in conjuction with fine needle aspiration cytology. Solitary nodule of the thyroid is a common entity whereas malignancy although rare needs a selective approach for further management and follow up

    Perfect Teleportation, Quantum state sharing and Superdense Coding through a Genuinely Entangled Five-qubit State

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    We investigate the usefulness of a recently introduced five qubit state by Brown \it et al. \normalfont \cite{Brown} for quantum teleportation, quantum state sharing and superdense coding. It is shown that this five-qubit state can be utilized for perfect teleportation of arbitrary single and two qubit systems. We devise various schemes for quantum state sharing of an arbitrary single and two particle state via cooperative teleportation. We later show that this state can be used for superdense coding as well. It is found that five classical bits can be sent by sending only three quantum bits.Comment: 8 Pages, added sections on state sharin

    Landauer-B\"uttiker approach for hyperfine mediated electronic transport in the integer quantum Hall regime

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    The interplay of spin-polarized electronic edge states with the dynamics of the host nuclei in quantum Hall systems presents rich and non-trivial transport physics. Here, we develop a Landauer-B\"uttiker approach to understand various experimental features observed in the integer quantum Hall set ups featuring quantum point contacts. The approach developed here entails a phenomenological description of spin resolved inter-edge scattering induced via hyperfine assisted electron-nuclear spin flip-flop processes. A self-consistent simulation framework between the nuclear spin dynamics and edge state electronic transport is presented in order to gain crucial insights into the dynamic nuclear polarization effects on electronic transport and in turn the electron-spin polarization effects on the nuclear spin dynamics. In particular, we show that the hysteresis noted experimentally in the conductance-voltage trace as well as in the resistively detected NMR lineshape results from a lack of quasi-equilibrium between electronic transport and nuclear polarization evolution. In addition, we present circuit models to emulate such hyperfine mediated transport effects to further facilitate a clear understanding of the electronic transport processes occurring around the quantum point contact. Finally, we extend our model to account for the effects of quadrupolar splitting of nuclear levels and also depict the electronic transport signatures that arise from single and multi-photon processes.Comment: 21 pages, 8 figure

    Turning turtle

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    In September this year, the Tamil Nadu Fisheries Department issued an order that banned all forms of fishing within a radius of 5 nautical miles (9.3 km) at 90 sites along the State’s coastline. It was passed to safeguard migrating olive ridley sea turtles. Extending from January to the end of April, the ban is applicable across eight coastal districts — from Chennai in the north to Kanyakumari in the south

    DEVELOPING A PERFORMANCE IMPORTANCE MATRIX FOR A PUBLIC SECTOR BUS TRANSPORT COMPANY: A CASE STUDY

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    This paper presents a study of comparison of the importance attached by the service providers’ and the customers’ with respect to eighteen service characteristics towards the public transportation services provided by a bus company. The survey was conducted in three bus depots in one division of a state road transport undertaking (SRTU) in south India. The importance the SRTU and the customers attach to these characteristics indicates significant differences. This reveals the existence of a gap between customers’ expectations and the service provided by the company. Finally the customer retention and customer development criteria have been. identified.Performance importance matrix, Customer expectations, Public bus transport, Radar chart.

    Development of Subcarangiform Bionic Robotic Fish Propelled by Shape Memory Alloy Actuators

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    In this paper, a shape memory alloy (SMA) actuated subcarangiform robotic fish has been demonstrated using a spring based propulsion mechanism. The bionic robotic fish developed using SMA spring actuators and light weight 3D printed components can be employed for under water applications. The proposed SMA spring-based design without conventional motor and other rotary actuators was able to achieve two-way shape memory effect and has reproduced the subcarangiform locomotion pattern. The positional kinematic model has been developed and the dynamics of the proposed mechanism were analysed and simulated using Automated Dynamic Analysis of Mechanical Systems (ADAMS). An open loop Arduino-relay based switching control has been adopted to control the periodic actuation of the SMA spring mechanism. The undulation of caudal fin in air and water medium has been analysed. The caudal fin and posterior body of the developed fish prototype have taken part in undulation resembling subcarangiform locomotion pattern and steady swimming was achieved in water with a forward velocity of 24.5 mm/s. The proposed design is scalable, light weight and cost effective which may be suitable for underwater surveillance application

    Resistively-detected NMR lineshapes in a quasi-one dimensional electron system

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    We observe variation in the resistively-detected nuclear magnetic resonance (RDNMR) lineshapes in quantum Hall breakdown. The breakdown is locally occurred in a gate-defined quantum point contact (QPC) region. Of particular interest is the observation of a dispersive lineshape occured when the bulk 2D electron gas (2DEG) is set to νb=2\nu_{\rm{b}} = 2 and the QPC filling factor to the vicinity of νQPC=1\nu_{\rm{QPC}} = 1, strikingly resemble the dispersive lineshape observed on a 2D quantum Hall state. This previously unobserved lineshape in a QPC points to simultaneous occurrence of two hyperfine-mediated spin flip-flop processes within the QPC. Those events give rise to two different sets of nuclei polarized in the opposite direction and positioned at a separate region with different degree of electronic polarizations.Comment: Accepted as a rapid communication in PR

    Rectification by charging -- the physics of contact-induced current asymmetry in molecular conductors

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    We outline the qualitatively different physics behind charging-induced current asymmetries in molecular conductors operating in the weakly interacting self-consistent field (SCF) and the strongly interacting Coulomb Blockade (CB) regimes. A conductance asymmetry arises in SCF because of the unequal mean-field potentials that shift a closed-shell conducting level differently for positive and negative bias. A very different current asymmetry arises for CB due to the unequal number of open-shell excitation channels at opposite bias voltages. The CB regime, dominated by single charge effects, typically requires a computationally demanding many-electron or Fock space description. However, our analysis of molecular Coulomb Blockade measurements reveals that many novel signatures can be explained using a {{simpler}} orthodox model that involves an incoherent sum of Fock space excitations and {\it{hence treats the molecule as a metallic dot or an island}}. This also reduces the complexity of the Fock space description by just including various charge configurations only, thus partially underscoring the importance of electronic structure, while retaining the essence of the single charge nature of the transport process. We finally point out, however, that the inclusion of electronic structure and hence well-resolved Fock space excitations is crucial in some notable examples.Comment: 12 pages, 10 figure
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