101 research outputs found
A novel fault location method for a cross-bonded hv cable system based on sheath current monitoring
In order to improve the practice in the operation and maintenance of high voltage (HV) cables, this paper proposes a fault location method based on the monitoring of cable sheath currents for use in cross-bonded HV cable systems. This method first analyzes the power–frequency component of the sheath current, which can be acquired at cable terminals and cable link boxes, using a Fast Fourier Transform (FFT). The cable segment where a fault occurs can be localized by the phase difference between the sheath currents at the two ends of the cable segment, because current would flow in the opposite direction towards the two ends of the cable segment with fault. Conversely, in other healthy cable segments of the same circuit, sheath currents would flow in the same direction. The exact fault position can then be located via electromagnetic time reversal (EMTR) analysis of the fault transients of the sheath current. The sheath currents have been simulated and analyzed by assuming a single-phase short-circuit fault to occur in every cable segment of a selected cross-bonded high voltage cable circuit. The sheath current monitoring system has been implemented in a 110 kV cable circuit in China. Results indicate that the proposed method is feasible and effective in location of HV cable short circuit faults
Feasibility study on lengthening the high-voltage cable section and reducing the number of cable joints via alternative bonding methods
The mesosphere is perhaps the least explored region in the atmosphere with very few methods of observing. This thesis will primarily be exploring a new technique for measuring the distribution of kinetic energy in the mesosphere across a wide range of spatial and temporal scales. The method being used relies on correlation functions between pairs of meteor measurements. These measurements are made using a network of specular meteor radars located in Northern Norway. This network produced 32 million meteor measurements over a 2 year period. The correlation function estimation method has been previously used on a smaller data set, but has so far not been used for a longer data set and at high latitudes. The main advantage of the new technique is that by studying the second order statistics of the wind field, we can obtain significantly better temporal and spatial resolution than before. Such a large data set allows for great resolution for both spatial and temporal correlation functions. By using temporal correlation functions and the kinetic energy spectrum, different atmospheric wave phenomena can be studied. These include diurnal and semi diurnal tides. The horizontal and vertical correlation functions will be used to verify that the kinetic energy follows a power law, as theoretically expected by the Kolmogorov theory for turbulence. This was done by using a second order structure function applied to correlation functions. The temporal and horizontal correlation functions were used to study the summer-winter variation in kinetic energy, some variation in the temporal domain is the impact from large scale waves as well as in the power spectra were there is a steeper power law slope during the winter. As for the horizontal domain there are differences in kinetic energy in the zonal and meridional direction for both large and small scale waves. The dataset in this thesis a lot more can be found out about the mesosphere, in this thesis only a few of the possibilities are explored. The results are in agreement with earlier work, confirming the results obtained by the earlier study
Feasibility study on lengthening the high-voltage cable section and reducing the number of cable joints via alternative bonding methods
Characterization of an aspartate aminotransferase encoded by YPO0623 with frequent nonsense mutations in Yersinia pestis
Yersinia pestis, the causative agent of plague, is a genetically monomorphic bacterial pathogen that evolved from Yersinia pseudotuberculosis approximately 7,400 years ago. We observed unusually frequent mutations in Y. pestis YPO0623, mostly resulting in protein translation termination, which implies a strong natural selection. These mutations were found in all phylogenetic lineages of Y. pestis, and there was no apparent pattern in the spatial distribution of the mutant strains. Based on these findings, we aimed to investigate the biological function of YPO0623 and the reasons for its frequent mutation in Y. pestis. Our in vitro and in vivo assays revealed that the deletion of YPO0623 enhanced the growth of Y. pestis in nutrient-rich environments and led to increased tolerance to heat and cold shocks. With RNA-seq analysis, we also discovered that the deletion of YPO0623 resulted in the upregulation of genes associated with the type VI secretion system (T6SS) at 26°C, which probably plays a crucial role in the response of Y. pestis to environment fluctuations. Furthermore, bioinformatic analysis showed that YPO0623 has high homology with a PLP-dependent aspartate aminotransferase in Salmonella enterica, and the enzyme activity assays confirmed its aspartate aminotransferase activity. However, the enzyme activity of YPO0623 was significantly lower than that in other bacteria. These observations provide some insights into the underlying reasons for the high-frequency nonsense mutations in YPO0623, and further investigations are needed to determine the exact mechanism
Construction and progress of Chinese terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation
31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two
Background
The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd.
Methods
We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background.
Results
First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001).
Conclusions
In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival
Polymorphisms of the β1-adrenergic receptor gene are associated with essential hypertension in Chinese
Background: The β1-adrenergic receptor (ADRB1) plays a pivotal role in mediating signal transduction of the sympathetic-adrenal system, which is involved in the regulation of cardiac output and peripheral resistance. Our goal was to determine whether the polymorphisms Arg389Gly (rs1801253) and Ser49Gly (rs1801252) of the ADRB1 gene were associated with essential hypertension in Chinese. Methods: We tested our hypothesis in two independent case-control studies, one comprised 481 patients with hypertension and 529 control subjects, and the other study comprised 212 patients and 325 control subjects. All subjects were genotyped for Arg389Gly and Ser49Gly polymorphisms. Results: The first study showed that the Arg389Arg genotype of the ADRB1 gene was associated with risk of hypertension [odds ratio (OR) 1.77, 95% confidence interval (CI) 1.09–2.98; p=0.008], and the association was replicated in the second independent population (OR 1.65, 95% CI 1.07–2.89, p=0.01). The patients with the Arg389Arg genotype had significantly higher diastolic blood pressure (DBP) than did those with Arg389Gly genotype as well as those with Gly389Gly genotype (100.29±11.01 mm Hg vs. 95.33±13.10 mm Hg and vs. 96.17±12.18 mm Hg, respectively, p=0.01, p=0.02). The association was replicated in the second study (103.7±13.3 mm Hg vs. 97.31±12.9 mm Hg and vs. 96.29±13.4 mm Hg, respectively, p=0.03, p=0.02). Heart rate also showed an association (in first study: 79.43±9.90 bpm vs. 74.87±8.96 bpm, vs. 73.92±8.18 bpm, respectively, p=0.02, p=0.014; in the second study: 81.12±8.99 bpm vs. 74.85±7.97 bpm and vs. 73.89±9.12 bpm, p=0.007, p=0.006, respectively). No association was seen between systolic blood pressure (SBP) and any of the three genotypes at amino acid position 389 in hypertensive patients, neither between the Ser49Gly polymorphisms and hypertension, nor between the Ser49Gly genotypes and DBP and heart rate. Conclusions: The polymorphisms of the ADRB1 gene were associated with essential hypertension. The Arg389Gly polymorphism of the ADRB1 gene confers higher risk for hypertension. Clin Chem Lab Med 2009;47:1227–31.Peer Reviewe
Decoding long-term trends in the wet deposition of sulfate, nitrate and ammonium after reducing the perturbation from climate anomalies
Abstract. Long-term trends of wet deposition of inorganic ions are affected by multiple factors, among which emission changes and climate conditions are dominant ones. To assess the effectiveness of emission reductions on the wet deposition of pollutants of interest, contributions from these factors to the long-term trends of wet deposition must be isolated. For this purpose, a two-step approach for preprocessing wet deposition data is presented herein. This new approach aims to reduce the impact of climate anomalies on the trend analysis so that the impact of emission reductions on wet deposition can be revealed. This approach is applied to a two-decade wet deposition dataset of sulfate (SO42−), nitrate (NO3−) and ammonium (NH4+) at rural Canadian sites. Analysis results show that the approach allows for robustly identifying inflection points on decreasing trends in the wet deposition fluxes of SO42− and NO3− in northern Ontario and Québec. The inflection points match well with the three-phase mitigation of SO2 emissions and two-phase mitigation of NOx emissions in Ontario. Improved correlations between the wet deposition of ions and their precursors' emissions were obtained after reducing the impact from climate anomalies. Furthermore, decadal climate anomalies were identified as dominating the decreasing trends in the wet deposition fluxes of SO42− and NO3− at a western coastal site. Long-term variations in NH4+ wet deposition showed no clear trends due to the compensating effects between NH3 emissions, climate anomalies, and chemistry associated with the emission changes of sulfur and nitrogen.
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Supplementary material to &quot;Trends in atmospheric ammonia at urban, rural and remote sites across North America&quot;
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