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A global view of power system's frequency behavior opens up a new window for analyzing system's dynamics. With the aid of global positioning system, measurements from different locations would have synchronous time; therefore a system-wide observation and analysis would be possible. As part of the US-wide power frequency monitoring network project this paper focus on simulation study results of power frequency dynamics of the Eastern U.S. system. The study assesses the frequency measurement accuracy needed to observe frequency dynamics from events such as remote generation drops. Electromechanical-wave propagation phenomena during system disturbances have been observed. The speeds of electromechanical-wave propagation in different areas of the U.S. systems were estimated and their characteristics were discussed. Index Terms--Electromechanical-wave propagation, power-system frequency, system dynamics, wide-area measurements (WAMs).

With the advances in semiconductor devices, adjustable-speed drives (ASD's) have become more prevalent than ever before in industrial and commercial processes. Many facilities are installing ASD's to improve the efficiency of their processes and to increase the control of their processes. While the effects of ASD's on the power system are well known, many engineers and systems integrators are not aware of the effects that ASD's can have on the motor that is driven by the drive. This paper describes the techniques used to measure, analyze, and simulate the problems associated with the use of pulsewidth modulation (PWM) ASD's to drive induction motors. Measures to mitigate these problems are also discussed. The electromagnetic transients program (EMTP) is used to simulate the phenomena, compare results against measurements, and evaluate mitigation techniques. Index Terms - ASD's, EMTP, induction motors, PWM drives, transients, traveling waves.

An EMTP-based arc furnace model was developed for evaluation of flicker concerns associated with supplying a large integrated steel mill as they go from one to two furnace operation and as system changes are implemented that will affect the short circuit capacity at the 230 kV power supply substation. The model includes a dynamic arc representation which is designed to be characteristic of the initial portions of the melt cycle when the arc characteristics are the most variable (worst flicker conditions). The flicker calculations are verified using previous measurements with one furnace operation. Flicker simulations were then performed to evaluate a variety of different possible system strengths with both one and two furnaces in operation. The primary flicker measure used for this study is the unweighted rms value of the fluctuation envelope, expressed as a percentage of the rms line-to-ground voltage magnitude. Key Words: Arc Furnace, Voltage Flicker, EMTP Model

Crop aboveground biomass (AGB) is one of the most important indicators in diagnosing and monitoring agricultural ecosystems. AGB estimation not only closely relates to monitoring crop yield and production but also contributes to the research about the carbon cycle process and global climate change. In this study, the AGB of rice was estimated by vegetation indices (VIs) from optical data (GF-1) and polarization parameters (PPs) from radar data (RADARSAT-2) by best-fitting regression function first. Then, considering the different characteristics of these two types of remote sensing data, the vegetation indices and polarization parameters were combined to estimate the rice AGB. The results showed that all the selected vegetation indices and most of the polarization parameters were significantly correlated with the measured rice biomass; CIgreen and Anisotropy presented the best performance (R2 = 0.6123, RMSE = 0.4861 kg/m2 and R2 = 0.6543, RMSE = 0.5418 kg/m2, respectively). Compared with a single index or parameter, the new hybrid index significantly improves the biomass estimation: R2 = 0.7049; RMSE = 0.4849 kg/m2. A sensitivity analysis further revealed that combining optical vegetation index and microwave bands maintains the good prediction of AGB during the whole rice growth period. The study has proved the potential of retrieving rice AGB jointly using optical images and SAR data. [ABSTRACT FROM AUTHOR]

Background: Circular RNAs (circRNAs) are widely expressed in human cells and are closely associated with cancer development. However, they have rarely been investigated in the context of nasopharyngeal carcinoma (NPC). Methods: We screened a new circRNA, circRNF13, in NPC cells using next-generation sequencing of mRNA. Reverse transcription polymerase chain reaction and RNA fluorescence in situ hybridization were used to detect circRNF13 expression in 12 non-tumor nasopharyngeal epithelial (NPE) tissues and 36 NPC samples. Cell proliferation was detected using MTT and flow cytometry assays, and colony formation capability was detected using colony formation assays. Cell migration and invasion were analyzed using wound-healing and Transwell assays, respectively. Cell glycolysis was analyzed using the Seahorse glycolytic stress test. Glucose transporter type 1 (GLUT1) ubiquitination and SUMOylation modifications were analyzed using co-immunoprecipitation and western blotting. CircRNF13 and Small Ubiquitin-like Modifier 2 (SUMO2) interactions were analyzed using RNA pull-down and luciferase reporter assays. Finally, to test whether circRNF13 inhibited NPC proliferation and metastasis in vivo, we used a xenograft nude mouse model generated by means of subcutaneous or tail vein injection. Results: We found that circRNF13 was stably expressed at low levels in NPC clinical tissues and NPC cells. In vitro and in vivo experiments showed that circRNF13 inhibited NPC proliferation and metastasis. Moreover, circRNF13 activated the SUMO2 protein by binding to the 3′- Untranslated Region (3′-UTR) of the SUMO2 gene and prolonging the half-life of SUMO2 mRNA. Upregulation of SUMO2 promotes GLUT1 degradation through SUMOylation and ubiquitination of GLUT1, which regulates the AMPK-mTOR pathway by inhibiting glycolysis, ultimately resulting in the proliferation and metastasis of NPC. Conclusions: Our results revealed that a novel circRNF13 plays an important role in the development of NPC through the circRNF13-SUMO2-GLUT1 axis. This study implies that circRNF13 mediates glycolysis in NPC by binding to SUMO2 and provides an important theoretical basis for further elucidating the pathogenesis of NPC and targeted therapy. [ABSTRACT FROM AUTHOR]

The contact lens prepared by the conventional soaking method using timolol-soaking solution showed poor drug uptake and high burst release with altered critical lens properties. In this study, timolol-loaded nanostructured lipid carriers (NLCs) were prepared and evaluated for enhanced timolol uptake and sustained release for the effective management of glaucoma. The characterization studies indicated that timolol-loaded NLCs were spherical in shape with an average size of 130–138 nm and a zeta potential of −46.6 to 51.3 mV. Critical lens properties such as swelling, optical transmittance, and protein adherence were improved with NLC-laden lenses compared to the conventional soaked lenses (SM-TB). Moreover, SM-TB lens showed low timolol uptake, high burst release, and short release duration up to 24 h compared to timolol-NLC-laden lens that showed high timolol uptake, and the cumulative release was sustained up to 96 h. The ability to sustain timolol release improved proportionally with an increase in the amount of Capmul MCMC8 (liquid lipid) in NLCs. In addition, NLC-laden lens was found to be safe according to the results of ocular irritation and histopathological studies. In the rabbit tear fluid model, NLC-30%-Cap-CL batch showed high timolol concentration at all time points up to 60 h. Further, pharmacodynamic study showed sustained reduction in IOP by NLC-30%-Cap-CL batch for 96 h compared to 48 h and 6 h with SM-TB lens and eye drop solution, respectively. In conclusion, NLCs enhanced timolol uptake in the contact lens from the soaking solution using soaking method with improved in vitro and in vivo results for better clinical outcomes in the patients with glaucoma. [ABSTRACT FROM AUTHOR]

Compact fluorescent lamps (CFLs) have the potential to increase the overall harmonic distortion levels on distribution systems. Measurements of the harmonic characteristics of different types of CFLs are presented and the possible impacts on a distribution system are analyzed. The analysis uses a combination of EMTP simulations and conventional harmonic analysis simulations to predict the distribution system distortion levels as a function of system characteristics, the CFL characteristics, and the CFL penetration level.

This paper analyzes an unusual flicker-like disturbance during the operation of a DC arc furnace. A harmonic resonance, excited by an excessive amount of uncharacteristic converter current harmonics, was the main cause of the disturbance. A study was performed in which the phenomenon was duplicated with the Electro-magnetic Transients Program. The simulation model and results are described. The generation of uncharacteristic converter current harmonics under normal and abnormal converter operation are demonstrated. The significant conditions leading to the unusual 187 Hz disturbance and flicker complaints are discussed.

The system configuration, theory of operation, computer simulations, and important application experiences of a small (750 kVA) superconducting magnetic energy storage device (Micro-SMES) for application on power distribution circuits to enhance customer power quality are presented. The functions of the major components of the Micro-SMES are separately discussed and the operation of each component is illustrated with an Electro-Magnetic Transients Program (EMTP) simulation example. Application performance characteristics obtained from the first practical installation of a Micro-SMES are summarized and its protection effectiveness is evaluated.

Intra‐tumour immune infiltration is a crucial determinant affecting immunotherapy response in non‐small cell lung cancer (NSCLC). However, its phenotype and related spatial structure have remained elusive. To overcome these restrictions, we undertook a comprehensive study comprising spatial transcriptomic (ST) data (28 712 spots from six samples). We identified two distinct intra‐tumour infiltration patterns: immune exclusion (characterised by myeloid cells) and immune activation (characterised by plasma cells). The immune exclusion and immune activation signatures showed adverse and favourable roles in NSCLC patients' survival, respectively. Notably, CD14+APOE+ cells were recognised as the main cell type in immune exclusion samples, with increased epithelial‒mesenchymal transition and decreased immune activities. The co‐location of CD14+APOE+ cells and MMP7+ tumour cells was observed in both ST and bulk transcriptomics data, validated by multiplex immunofluorescence performed on 20 NSCLC samples. The co‐location area exhibited the upregulation of proliferation‐related pathways and hypoxia activities. This co‐localisation inhibited T‐cell infiltration and the formation of tertiary lymphoid structures. Both CD14+APOE+ cells and MMP7+ tumour cells were associated with worse survival. In an immunotherapy cohort from the ORIENT‐3 clinical trial, NSCLC patients who responded unfavourably exhibited higher infiltration of CD14+APOE+ cells and MMP7+ tumour cells. Within the co‐location area, the MK, SEMA3 and Macrophage migration inhibitory factor (MIF) signalling pathway was most active in cell‒cell communication. This study identified immune exclusion and activation patterns in NSCLC and the co‐location of CD14+APOE+ cells and MMP7+ tumour cells as contributors to immune resistance. [ABSTRACT FROM AUTHOR]

In this paper, a capacitor failure at a wind energy electric generation facility is investigated. The probable cause of the capacitor failures is identified to be overvoltage resulting from self-excitation of the induction generators. Relationships between the voltage escalation and the characteristics of the wind turbines is evaluated. Results of time domain digital simulation are presented along with a comprehensive explanation for this particular type of self-excitation phenomenon. The nature of the problem indicates that similar events could occur in any windfarm which uses capacitor compensation for the reactive power demand of induction generators. Methods for avoiding occurrences similar to that described in this paper are discussed.