38 research outputs found

    Using BDH for the Message Authentication in VANET

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    The transport message security provided by vehicles in VANETs is quite important; vehicle message should be real-time and it will be not complicated to validate message calculation. The method proposed in the essay is mainly to validate the identity by means of Bilinear Diffie-Hellman method, and make vehicles validate the authenticity of RSU and TA’s identity and the effectiveness of key. RSU and TA only need to validate vehicle identity, without helping vehicles produce any key. When vehicle identity validation is completed, vehicles will produce public value and transmit it to other RSU and vehicles, while other vehicles could validate the identity through the message from the sender and public value from RSU. The advantages of the method proposed in this essay are listed as follows. (1) Vehicles, RSU, and TA can validate mutual identities and the effectiveness of keys. (2) Vehicles can produce public value functions automatically, thus reducing key control risks. (3) Vehicles do not need to show certificates to validate their identities, preventing the certificates from attacking because of long-term exposure. (4) Vehicles adopt a pseudonym ID challenge to validate their own identities during the process of handoff. (5) Vehicle messages can be validated using the Bilinear Diffie-Hellman (BDH) method without waiting for the RSU to validate messages, thus improving the instantaneity of messaging. The method proposed in the essay can satisfy source authentication, message integrity, nonrepudiation, privacy, and conditional untraceability requirements

    Regulatory T Cells: Potential Target in Anticancer Immunotherapy

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    SummaryThe concept of regulatory T cells was first described in the early 1970s, and regulatory T cells were called suppressive T cells at that time. Studies that followed have demonstrated that these suppressive T cells negatively regulated tumor immunity and contributed to tumor growth in mice. Despite the importance of these studies, there was extensive skepticism about the existence of these cells, and the concept of suppressive T cells left the center stage of immunologic research for decades. Interleukin-2 receptor α-chain, CD25, was first demonstrated in 1995 to serve as a phenotypic marker for CD4+ regulatory cells. Henceforth, research of regulatory T cells boomed. Regulatory T cells are involved in the pathogenesis of cancer, autoimmune disease, transplantation immunology, and immune tolerance in pregnancy. Recent evidence has demonstrated that regulatory T cellmediated immunosuppression is one of the crucial tumor immune evasion mechanisms and the main obstacle of successful cancer immunotherapy. The mechanism and the potential clinical application of regulatory T cells in cancer immunotherapy are discussed

    Associations between Arsenic in Drinking Water and Pterygium in Southwestern Taiwan

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    [[abstract]]BACKGROUND: Pterygium is a fibrovascular growth of the bulbar conjunctiva and underlying subconjunctival tissue that may cause blindness. The mechanism of pterygium formation is not yet fully understood, but pterygium has some tumorlike features. OBJECTIVES: The objective of this study was to evaluate the association between arsenic exposure through drinking water and the occurrence of pterygium in southwestern Taiwan. METHODS: We recruited participants > 40 years of age from three villages in the arseniasis-endemic area in southwestern Taiwan (exposure villages) and four neighboring nonendemic villages (comparison villages). Each participant received an eye examination and a questionnaire interview. Photographs taken of both eyes were later graded by an ophthalmologist to determine pterygium status. RESULTS: We included 223 participants from the exposure villages and 160 from the comparison villages. The prevalence of pterygium was higher in the exposure villages across an age groups in both sexes and increased with cumulative arsenic exposure. We found a significant association between cumulative arsenic exposure and the prevalence of pterygium. After adjusting for age, sex, working under sunlight, and working in sandy environments, we found that cumulative arsenic exposure of 0.1-15.0 mg/L-year and >= 15.1 mg/L-year were associated with increased risks of developing pterygium. The adjusted odds ratios were 2.04 [95% confidence interval (CI), 1.04-3.99] and 2.88 (95% CI, 1.42-5.83), respectively. CONCLUSIONS: Chronic exposure to arsenic in drinking water was related to the occurrence of pterygium, and the association was still observed after adjusting for exposures to sunlight and sandy environments

    CYP17 genetic polymorphism, breast cancer, and breast cancer risk factors: Australian Breast Cancer Family Study

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    INTRODUCTION: Because CYP17 can influence the degree of exposure of breast tissues to oestrogen, the interaction between polymorphisms in this gene and hormonal risk factors is of particular interest. We attempted to replicate the findings of studies assessing such interactions with the -34T→C polymorphism. METHODS: Risk factor and CYP17 genotyping data were derived from a large Australian population-based case-control-family study of 1,284 breast cancer cases and 679 controls. Crude and adjusted odds ratio (OR) estimates and 95% confidence intervals (CIs) were calculated by unconditional logistic regression analyses. RESULTS: We found no associations between the CYP17 genotype and breast cancer overall. Premenopausal controls with A(2)/A(2 )genotype had a later age at menarche (P < 0.01). The only associations near statistical significance were that postmenopausal women with A(1)/A(1 )(wild-type) genotype had an increased risk of breast cancer if they had ever used hormone replacement therapy (OR 2.40, 95% CI 1.0 to 5.7; P = 0.05) and if they had menopause after age 47 years (OR 2.59, 95% CI 1.0 to 7.0; P = 0.06). We found no associations in common with any other studies, and no evidence for interactions. CONCLUSION: We observed no evidence of effect modification of reproductive risk factors by CYP17 genotype, although the experiment did not have sufficient statistical power to detect small main effects and modest effects in subgroups. Associations found only in subgroup analyses based on relatively small numbers require cautious interpretation without confirmation by other studies. This emphasizes the need for replication in multiple and large population-based studies to provide convincing evidence for gene–environment interactions

    Thyroid-Associated Orbitopathy with Superior Oblique Muscle Involvement: A Case Report

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    A 29-year-old male with a 5-year-history of hyperthyroidism complained of diplopia and proptosis. After subtotal thyroidectomy, he still had diplopia in a certain gaze. Computerized tomography showed inferior rectus muscle enlargement in the right eye and inferior rectus, medial rectus, and superior oblique muscle enlargement in the left eye. Ocular examination with the cover and uncover test revealed hyperphoria and exophoria in the left eye. The upward gaze of the right eye was more limited than that of the left eye. Since superior oblique muscle involvement in patients with thyroid orbitopathy is quite rare, we discuss its effect on ocular motility in patients with thyroid-associated orbitopathy

    Three-input-one-output current-mode universal biquadratic filter using one differential difference current conveyor

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    A current-mode universal biquadratic filter is presented. The architecture has three input terminals, one output terminal using one differential difference current conveyor (DDCC), two grounded capacitors and two resistors. It can realize all standard second-order filter functions, which are, highpass, bandpass, lowpass, notch and allpass responses without changing the circuit topology. The proposed circuit employs only one DDCC that simplifies the circuit configuration.A current-mode universal biquadratic filter is presented. The architecture has three input terminals, one output terminal using one differential difference current conveyor (DDCC), two grounded capacitors and two resistors. It can realize all standard second-order filter functions, which are, highpass, bandpass, lowpass, notch and allpass responses without changing the circuit topology. The proposed circuit employs only one DDCC that simplifies the circuit configuration

    Current-mode and transimpedance-mode universal biquadratic filter using two current conveyors

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    461-468A current-mode and transimpedance-mode universal biquadratic filter with single input and multi-outputs using two current conveyors, four resistors and two grounded capacitors is presented. The proposed circuit can realize current-mode notch, highpass and bandpass responses, simultaneously. The current-mode lowpass and allpass responses can be obtained by interconnection of relevant output currents. Moreover, the transimpedance-mode highpass, bandpass, lowpass, notch and allpass filters can also be obtained, simultaneously, from the proposed circuit

    Fully differential first-order allpass filters using a DDCC

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    Two voltage-mode high input impedance differential input-differential output first-order allpass filters based on differential difference current conveyor (DDCC) are presented. Each of the proposed circuit uses one plus-type DDCC, one grounded capacitor and three resistors. The proposed circuits enjoy the features of high input impedance, tunable of the allpass gains and using only grounded capacitors. The tracking error and sensitivity analysis of the proposed circuits are given. Simulation results confirm the theoretical analysis.Two voltage-mode high input impedance differential input-differential output first-order allpass filters based on differential difference current conveyor (DDCC) are presented. Each of the proposed circuit uses one plus-type DDCC, one grounded capacitor and three resistors. The proposed circuits enjoy the features of high input impedance, tunable of the allpass gains and using only grounded capacitors. The tracking error and sensitivity analysis of the proposed circuits are given. Simulation results confirm the theoretical analysis

    Voltage/Current-Mode Multifunction Filters Using Current-Feedback Amplifiers and Grounded Capacitors

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    One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters each using two current-feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibits simultaneously lowpass, bandpass, and highpass filters. The proposed current-mode circuit also exhibits simultaneously lowpass, bandpass, and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions, low active and passive sensitivities, employing only grounded capacitors, and the ability to obtain multi-function filters from the same circuit configuration
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