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In this study, a phase-generated carrier (PGC) demodulation algorithm combined with the extended Kalman filter (EKF) algorithm based on an electro-optic modulator (EOM) is proposed, which can achieve nonlinear distortion (such as modulation depth drift and carrier phase delay) suppression for high-frequency phase carrier modulation. The improved algorithm is implemented on a field-programmable gate array (FPGA) hardware platform. The experimental results by the PGC-EKF method show that total harmonic distortion (THD) decreases from −32.61 to −54.51 dB, and SINAD increases from 32.59 to 47.86 dB, compared to the traditional PGC-Arctan method. This indicates that the PGC-EKF demodulation algorithm proposed in this paper can be widely used in many important fields such as hydrophone, transformer, and ultrasound signal detection. [ABSTRACT FROM AUTHOR]

Objective Individual differences challenge the treatment of vancomycin, linezolid and voriconazole in severe infections. This study aimed to build a simple and economical method for simultaneous determination of the three antibiotics in human plasma by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) and provided a reference for therapeutic drug monitoring (TDM) of infected patients. Methods The plasma samples were precipitated by acetonitrile and detected and separated on a shim-pack GIST C18 column following the gradient elution within 5 min. Mass quantification was performed on multiple reaction monitoring mode under positive electrospray ionization. Results The linear ranges of vancomycin, linezolid and voriconazole were 1.00–100.00, 0.10–15.00 and 0.10–20.00 μg·mL−1, respectively, with good linearity (R 2 > 0.99). The accuracy and precision, matrix effect, extraction recovery and stability were validated, and the results all meet the acceptance criteria of China Food and Drug Administration (CFDA) guidelines. Conclusion The UHPLC–MS/MS method was established and validated for the simultaneous determination of vancomycin, linezolid and voriconazole in human plasma and successfully applied to routine TDM for individualized treatment. [ABSTRACT FROM AUTHOR]

The sparse triangular solver (SpTRSV) is mostly used for scientific and engineering applications. The structured-grid triangular solver of regular dependencies (STRSV) is a special kind of SpTRSV. Some general SpTRSVs that disregards the regularity of the matrix are unsuitable for solving this problem. This paper proposes an efficient parallel algorithm for STRSV on the SW26010 (a kind of China independently designed many-core processors), namely swStructTRSV. The algorithm makes full use of the fine-grained and low latency communication characteristics of the SW26010 to reduce the waiting time for synchronization, maximizes the regularity of access to improve memory access bandwidth, and achieves overlap between memory access and computation simultaneously. Moreover, the idea of the algorithm can be extended to incomplete LU factorization (ILU factorization) because of consistent dependencies. The experimental results on a core group(8 * 8 network composed of 64 cores) of SW26010 show that swStructTRSV can achieve an average speedup of over 30 in the sequential version. swStructTRSV on SW26010 achieves solving speedups of 2.2 and 6.3 over the fast STRSV (fSpTRSV) previously implemented on SW26010 and MKL on Intel Xeon Gold 6132, respectively. swStructTRSV significantly outperforms cuSparse on NVIDIA TITAN RTX in terms of overall execution time. [ABSTRACT FROM AUTHOR]

Anlotinib and osimertinib are a class of tyrosine kinase inhibitors for the treatment of malignant tumor. The combination of anlotinib and osimertinib is currently used for treating non-small cell lung cancer (NSCLC) patients. This study aimed to develop a simple and rapid isotope-labeled UHPLC–MS/MS method for the simultaneous determination of anlotinib and osimertinib in human plasma. The analytes were extracted by protein precipitation with acetonitrile and were then separated on a Shim-pack GIST C18 column. The detection was performed on Shimadzu 8050 triple quadruple mass spectrometer in the positive electrospray ionization mode with multiple reaction monitoring. The precursor-to-product ion transitions were m/z 408.10→ 339.75, 500.25→ 72.20 and 413.50 → 344.50 for anlotinib, osimertinib and D5-anlotinib, respectively. Validation is based on US Food and Drug Administration guidelines. The linearity ranges were 0.5–100 ng/mL for anlotinib and were 1–500 ng/mL for osimertinib with the correlation coefficients (r  2) ≥ 0.99. Accuracy and precision, matrix effect, extraction recovery and stability of anlotinib and osimertinib were acceptable after validation. The UHPLC–MS/MS method was successfully validated and was applied to monitor the concentration of anlotinib and osimertinib in NSCLC patients. [ABSTRACT FROM AUTHOR]

Dissolved gas analysis is an important method for diagnosing the operating condition of power transformers. Traditional methods such as IEC Ratios and Duval Triangles and Pentagon methods are not applicable in the case of abnormal or missing values of DGA data. A novel transformer fault diagnosis method based on an extreme gradient boosting algorithm is proposed in this paper. First, the traditional statistical method is replaced by the random forest regression algorithm for filling in missing values of dissolved gas data. Normalization and feature derivation of the outlier data is adopted based on the gas content. Then, hyperparameter optimization of the transformer fault diagnosis model based on an extreme gradient boosting algorithm is carried out using the tree-structured probability density estimator algorithm. Finally, the influence of missing data and optimization algorithms on transformer fault diagnosis models is analyzed. The effects of different algorithms based on incomplete datasets are also discussed. The results show that the performance of the random forest regression algorithm on missing data filling is better than classification and regression trees and traditional statistical methods. The average accuracy of the fault diagnosis method proposed in the paper is 89.5%, even when the missing data rate reaches 20%. The accuracy and robustness of the TPE-XGBoost model are superior to other machine learning algorithms described in this paper, such as k-nearest neighbor, deep neural networks, random forest, etc. [ABSTRACT FROM AUTHOR]

As a common incipient fault for a compensation capacitor, the internal capacitor element breakdown fault (CEBF) causes slight changes in the steady-state voltage and current, which are difficult to accurately capture under the influence of measurement error. Therefore, to meet the demand for intelligent equipment maintenance by a smart grid, transient disturbances induced by a CEBF are used in this study to acquire element breakdown information for online monitoring of capacitor health. A transient response analysis of the CEBF in the time and frequency domains is used to establish the typical transient characteristics. Then, a multiple-kernel support vector machine algorithm is adopted to identify the transient disturbances. A method for determining the faulty capacitor unit is proposed based on the position of the waveform monitor. Under the assumption and statistics of the number of failed elements in a series group, a scheme for assessing the health condition is investigated. The proposed method can effectively obtain breakdown information to assess capacitor health with little influence of measurement error and background noise. The results of a theoretical analysis, computer simulation, lab experiment and field monitoring verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The capacitor energizing transient as a kind of typical disturbance is used in the studies of power quality, condition monitoring, and other fields, and all studies heavily rely on transient characteristics. However, most characteristics are established based on the three-phase capacitor synchronous energizing (SE), and the effect of asynchronous energizing (AE) is neglected, which may affect the relevant studies. In this paper, the main characterizations of the capacitor AE transient, such as the oscillation frequency, time constant, and transient magnitude are analyzed considering the operation modes of the system and capacitor neutral points. The effect of the three-phase circuit asymmetry on the characterizations is investigated. The downstream voltage magnification phenomena in not only positive-sequence circuit but also zero-sequence circuit caused by the capacitor AE are also revealed. The theoretical analysis, computer simulation and lab experiment results have verified the effectiveness of the characteristics. [ABSTRACT FROM AUTHOR]

Effective therapies are urgently needed for the SARS-CoV-2 pandemic. Chloroquine has been proved to have antiviral effect against coronavirus in vitro. In this study, we aimed to assess the efficacy and safety of chloroquine with different doses in COVID-19. In this multicenter prospective observational study, we enrolled patients older than 18 years old with confirmed SARS-CoV-2 infection excluding critical cases from 12 hospitals in Guangdong and Hubei Provinces. Eligible patients received chloroquine phosphate 500 mg, orally, once (half dose) or twice (full dose) daily. Patients treated with non-chloroquine therapy were included as historical controls. The primary endpoint is the time to undetectable viral RNA. Secondary outcomes include the proportion of patients with undetectable viral RNA by day 10 and 14, hospitalization time, duration of fever, and adverse events. A total of 197 patients completed chloroquine treatment, and 176 patients were included as historical controls. The median time to achieve an undetectable viral RNA was shorter in chloroquine than in non-chloroquine (absolute difference in medians −6.0 days; 95% CI −6.0 to −4.0). The duration of fever is shorter in chloroquine (geometric mean ratio 0.6; 95% CI 0.5 to 0.8). No serious adverse events were observed in the chloroquine group. Patients treated with half dose experienced lower rate of adverse events than with full dose. Although randomized trials are needed for further evaluation, this study provides evidence for safety and efficacy of chloroquine in COVID-19 and suggests that chloroquine can be a cost-effective therapy for combating the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

A novel scheme is proposed to monitor the operation of capacitors scattered in MV distribution systems. It first codes each capacitor with a distinctive switching character by setting a unique combination of a three-phase switching order and time interval. As a result, the transient of the three-phase reactive power during capacitor switching will appear in a unique way. Then, the reactive power disturbances monitored in the substation are decoded to identify which capacitor is being switchedonandoff. A detailed decoding method is developed to realize this identification without being impacted by the switching interference of loads and other reactive power compensation devices. Moreover, the implementation of the proposed scheme in the field is elaborated, and the resultant three-phase voltage unbalance is analyzed in this paper. Compared with existing methods, this scheme only requires one power quality monitor located at the substation to monitor the operations (energizing or de-energizing) of downstream distribution capacitors without extra communication devices. The operation information is valuable for tackling power quality problems caused by capacitor switching and optimizing the distribution grid operation. [ABSTRACT FROM AUTHOR]

In this study, the active noise control (ANC) method was used to suppress high-decibel and low-frequency power transformer noise. An appropriate ANC system was selected based on the transformer noise characteristics and experimental condition. A new filter-X least mean square (FXLMS) adaptive ANC algorithm based on offline and online secondary-path modeling was proposed to realize faster and more stable secondary-path online modeling than that of the random white-noise FXLMS algorithm and to ensure the convergence, stability, and reduction in transformer noise control. Moreover, the genetic algorithm is adopted to optimize the convergence coefficient, while the effect of the convergence coefficient on the algorithm was analyzed using simulation and theory. In addition, the transformer noise online monitoring and active control system was designed including software and hardware, and the hardware devices were selected based on the noise feature. In the 50 000 KVA transformer noise reduction experiment, the system achieved a noise reduction of 8–15 dB and an 84.10–96.86% decrease in average sound energy density in a certain area. [ABSTRACT FROM PUBLISHER]

A liquid chromatography-tandem mass spectrometry was developed and validated for the simultaneous determination of protocatechuic aldehyde, danshensu, salvianolic acid B, and hydroxysafflor yellow A, with rutin as internal standard. Electrospray ionization patterns and efficiency of the analytes, along with their fragmentation, were investigated to achieve sensitive electrospray tandem mass spectrometry (ESI-MS/MS) detection. Plasma samples were extracted by solid-phase extraction columns, and the analytes were separated on a Dikma Diamonsil C18 (200 mm×4.6 mm i.d., 5 µm) column using a mobile phase comprised of methanol:acetonitrile: 0.5% formic acid (20:25:55, v/v/v) at a flow rate of 1 ml/min. Detection was performed on a Finnigan TSQ ripple quadrupole tandem mass spectrometer in negative ion-selected monitoring mode using electrospray ionization. Good linearity over the range 10-1000 ng/ml for danshensu, salvianolic acid B, and hydroxysafflor yellow A, and 5-500 ng/ml for protocatechuic aldehyde with acceptable accuracy and precision, respectively. All the validation data, such as accuracy, precision, and stability, were within the required limits. It was a potential platform for the pharmacokinetic and absorption, distribution, metabolism, and excretion (ADME) study of multiple constituent traditional Chinese medicine. [ABSTRACT FROM AUTHOR]