62 research outputs found

    Doxycycline Regulated Induction of AKT in Murine Prostate Drives Proliferation Independently of p27 Cyclin Dependent Kinase Inhibitor Downregulation

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    The PI3 kinase/AKT pathway has been shown to increase degradation of the p27 cyclin dependent kinase inhibitor through phosphorylation of consensus AKT sites on p27 and SKP2, and AKT driven proliferation may be checked by feedback mechanisms that increase p27 expression and induce senescence. However, these AKT sites are not conserved in mouse, and it has not been clear whether AKT negatively regulates murine p27. Transgenic mice with a probasin promoter controlled prostate specific reverse tetracycline transactivator (ARR2Pb-rtTA) were generated and used to achieve doxycycline inducible expression of a tetracycline operon regulated constitutively active myristoylated AKT1 transgene (tetO-myrAKT). Doxycycline induction of myrAKT occurred within 1 day and rapidly induced proliferation (within 4 days) and the development of prostatic intraepithelial neoplasia (PIN) lesions in ventral prostate, which did not progress to prostate cancer. Cells in these lesions expressed high levels of p27, had increased proliferation, and there was apoptosis of centrally located cells. Doxycycline withdrawal resulted in apoptosis of cells throughout the lesions and rapid clearing of hyperplastic glands, confirming in vivo the critical antiapoptotic functions of AKT. Significantly, analyses of prostates immediately after initiating doxycycline treatment further showed that p27 expression was rapidly increased, coincident with the induction of myrAKT and prior to the development of hyperplasia and PIN. These findings establish in vivo that murine p27 is not negatively regulated by AKT and indicate that proliferation in PI3 kinase/AKT pathway driven mouse models is mediated by p27 independent mechanisms that may be distinct from those in human. Further studies using prostate specific doxycycline regulated transgene expression may be useful to assess the acute effects of inducing additional transgenes in adult murine prostate epithelium, and to assess the requirements for continued transgene expression in transgene induced tumors

    Association between the C-reactive protein/albumin ratio and mortality in older Japanese patients with dysphagia

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    BackgroundC-reactive protein-to-albumin ratio (CRP/ALB) has been proven to represent a biomarker for predicting prognosis in many groups of patients with severe diseases. However, few studies have investigated the association between CRP/ALB and mortality in Japan older people with dysphagia patients.ObjectiveThis retrospective cohort study aimed to assess the prognostic value of C-reactive protein/albumin ratio (CAR) in older Japanese patients with dysphagia.MethodsWe analyzed data from 253 patients diagnosed with dysphagia at a single center between January 2014 and January 2017. Cox regression analysis was used to compare the mortality rates across the CAR tertiles. Subgroup analyses were conducted, and Kaplan–Meier curves were used to determine the median survival times.ResultsThe study included 154 female and 99 male patients, with a median age of 83 years. After adjusting for all covariates, the multivariable Cox regression analysis revealed a significant association between increasing CAR (HR = 1.19, 95% CI: 1.03–1.37, P = 0.022) and the risk of mortality. Compared to the reference group T1 (< 0.149), the adjusted hazard ratios for T2 (0.149–0.815) and T3 (> 0.815) were 1.75 (95% CI: 1.07–2.87, P = 0.027) and 2.15 (95% CI: 1.34–3.46, P = 0.002), respectively. Kaplan–Meier curves indicated median survival times of 864, 371, and 223 days for T1, T2, and T3, respectively.ConclusionThe C-reactive protein/albumin ratio was positively related to mortality in Japan older people with dysphagia patients. There was no interaction for the subgroup analysis. The result was stable

    Design of a UHF Antenna for Partial Discharge Detection of Power Equipment

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    A single-arm Archimedean spiral antenna that can be directly fed by a 50 Ω coaxial cable is investigated in this study. Every antenna parameter is optimized under simulation to make the antenna work in the ultra-high frequency band. The influence of dielectric materials, feed cone angle, and antenna duty ratio is also examined. Partial discharge (PD) experiments on several typical artificial insulation defects are conducted, and a single-arm Archimedean spiral antenna and a typical microstrip antenna are utilized for PD measurement. The PD characteristics of different insulation defects are also analyzed. Results show that the designed antenna is suitable for ultra-high frequency monitoring. The detection sensitivity of the single-arm spiral antenna is superior to that of the ordinary microstrip antenna. The former can be utilized in wide-band measurement fields

    Study of the Impact of Initial Moisture Content in Oil Impregnated Insulation Paper on Thermal Aging Rate of Condenser Bushing

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    This paper studied the impact of moisture on the correlated characteristics of the condenser bushings oil-paper insulation system. The oil-impregnated paper samples underwent accelerated thermal aging at 130 °C after preparation at different initial moisture contents (1%, 3%, 5% and 7%). All the samples were extracted periodically for the measurement of the moisture content, the degree of polymerization (DP) and frequency domain dielectric spectroscopy (FDS). Next, the measurement results of samples were compared to the related research results of transformer oil-paper insulation, offering a theoretical basis of the parameter analysis. The obtained results show that the moisture fluctuation amplitude can reflect the different initial moisture contents of insulating paper and the mass ratio of oil and paper has little impact on the moisture content fluctuation pattern in oil-paper but has a great impact on moisture fluctuation amplitude; reduction of DP presents an accelerating trend with the increase of initial moisture content, and the aging rate of test samples is higher under low moisture content but lower under high moisture content compared to the insulation paper in transformers. Two obvious “deceleration zones” appeared in the dielectric spectrum with the decrease of frequency, and not only does the integral value of dielectric dissipation factor (tan δ) reflect the aging degree, but it reflects the moisture content in solid insulation. These types of research in this paper can be applied to evaluate the condition of humidified insulation and the aging state of solid insulation for condenser bushings

    Thermodynamic analysis of a new ammonia-water power cycle

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    A new ammonia-water power cycle (AWPC) basing on Kalina cycle is presented in this paper, which supply an effective way for low-moderate temperature geothermal power in China. The thermodynamic models of AWPC are established considering of the ratio of power generation as the optimization objective, and the binary cycle systems are analyzed. The theoretical results of AWPC show that there exists the optimum circulation ratio of 4, along with concentration difference of the ammonia-water solution of 12%-13%. And higher concentration of the ammonia-water solution will improve the performance of AWPC, while adding terminal temperature difference of the solution heat exchanger will improve the ratio of power generation

    A Three-Coil Inductively Power Transfer System with Constant Voltage Output

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    For a traditional 2-coil system outputting constant voltage (CV), the transfer efficiency decreases drastically as transfer distance increases. To solve this problem, this essay proposes a 3-coil system which could achieve CV output and Zero Phase Angle (ZPA) conditions with specific parameter values. This 3-coil system could partly relief transfer efficiency fall at a long transfer distance, without any complicated controls. In order to achieve CV and ZPA condition, this essay devises the parameter values based on the decoupling 3-coil model, and a prototype is designed accordingly to verify these characteristics. With 10 cm transfer distance, output voltage deviation is 5.5% as the load varies from 12 Ω to 200 Ω, proving that the output voltage almost keeps constant with load change. Furthermore, with software simulation, a comparison experiment between the proposed 3-coil system and a Series-Inductor-Capacitor-Inductor (S-LCL) compensated 2-coil system is built to verify the efficiency improvement. The transfer distance change leads to the differentiation of voltage gain for both 2-coil and 3-coil systems. So, the input voltage for both systems and the compensated capacitor in receiver loop of the 3-coil system are manipulated for keeping 60 V output voltage on the 12 Ω load. With distance increasing from 10 cm to 20 cm, transfer efficiency varies from 92.61 to 48.9% for the 2-coil system, and from 92.89 to 84.26% for the 3-coil system, effectively proving the efficiency improvement. The experiment and simulation results prove the effectiveness of the proposed method

    ClusterRep: A cluster-based reputation framework for balancing privacy and trust in vehicular participatory sensing

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    In vehicular participatory sensing, vehicles may provide false data or low-quality data. Building trust in vehicular ad hoc networks is an efficient way to deal with this issue. On one hand, vehicles need to disclose necessary information to demonstrate their trustworthiness. On the other hand, vehicles tend to hide their sensitive information to preserve user privacy. Therefore, privacy and trust are conflict in vehicular ad hoc networks. A cluster-based reputation framework named ClusterRep is proposed to balance privacy and trust in vehicular ad hoc networks. In this framework, the cluster head collaborates with cluster members to change pseudonyms and reputation values. The experiments show the scalability and the effectiveness of the ClusterRep compared with Beta strategy and IncogniSense-floor strategy

    Application of a Multi-Strategy Improved Sparrow Search Algorithm in Bridge Crane PID Control Systems

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    To address the anti-swing issue of the payload in bridge cranes, Proportional–Integral–Derivative (PID) control is a commonly used method. However, parameter tuning of the PID controller relies on empirical knowledge and often leads to system overshoot. This paper proposes an Improved Sparrow Search Algorithm (ISSA) to optimize the gains of PID controllers, alleviating adverse effects on payload oscillation and trolley positioning during the operation of overhead cranes. First, tent map chaos mapping is introduced to initialize the sparrow population, enhancing the algorithm’s global search capability. Then, by integrating sine and cosine concepts along with nonlinear learning factors, the updating mechanism of discoverer positions is dynamically adjusted, expediting the solving process. Finally, the Lévy flight strategy is employed to update follower positions, thereby enhancing the algorithm’s local escape capability. Additionally, a fitness function containing overshoot penalties is proposed to address overshoot issues. Simulation results indicate that the overshoot rates of all algorithms remain less than 3%. Moreover, compared with the Sparrow Search Algorithm (SSA), Particle Swarm Optimization (PSO), Simulated Annealing (SA), and Whale optimization Algorithm (WOA), the optimized PID control system with the ISSA algorithm exhibits superior control performance and possesses certain robustness and adaptability
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