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A double synchronous unified virtual oscillator controller (dsUVOC) is proposed for grid-forming voltage source converters to achieve synchronization to the fundamental frequency positive- and negative-sequence components of unbalanced or distorted grids. The proposed controller leverages a positive- and a negative-sequence virtual oscillator, a double-sequence current reference generator, and a double-sequence vector limiter. Under fault conditions, the controller enables to clamp the converter output current below the maximum value limited by the converter hardware while retaining synchronization without a phase-locked-loop (PLL) regardless of the balanced or unbalanced nature of grid faults. Consequently, balanced and unbalanced fault ride-through can be achieved without the need for switching to a back-up controller. The paper presents the systematic development of the double-synchronous structure along with detail design and implementation guidelines. Validation of the proposed controller is provided through extensive control-hardware-in-the-loop (CHIL) and laboratory hardware experiments.

The effect of the termination structure on the unclamped inductive switching (UIS) failure is analyzed for two kinds of SiC MOSFET, where S-MOS and G-MOS termination structure are adopted. The MOSFETs are named as S-MOS and G-MOS according to the buses connecting with different electrodes in the termination region. The experimental results indicate that the avalanche energy G-MOS can withstand is 1.15 times larger than that of S-MOS. To understand what are the factors that lead to different UIS capabilities, further static measurements and hotpot mapping after UIS test are done, and technology computer aided design (TCAD) simulation also is done to further confirm the principle.

Virtual inertia is an effective control approach to attenuate sudden voltage changes during transient events in low-inertia DC grids. While methods have been proposed to implement virtual inertia, its impact on DC grid stability in the presence of constant power loads (CPLs) remains unclear. In this paper, we perform a rigorous stability analysis for DC grids with CPLs powered by virtual-inertia-enhanced converters. We derive a closed-form stability criterion that can be used to evaluate the impact of virtual inertia on the system stability, and demonstrate that, given a set of system parameters, the stability of a DC grid powering CPLs can be improved for a range of virtual inertia designs. We provide analytical expressions for the optimal virtual inertia that improves stability and for the maximum virtual inertia that does not deteriorate stability. In addition, we present a step-by-step guideline to design a stable DC grid with virtual inertia. Test results are presented to validate the analysis., Comment: replaced with the published version

Panchromatic and multispectral image fusion, termed pan-sharpening, is to merge the spatial and spectral information of the source images into a fused one, which has a higher spatial and spectral resolution and is more reliable for downstream tasks compared with any of the source images. It has been widely applied to image interpretation and pre-processing of various applications. A large number of methods have been proposed to achieve better fusion results by considering the spatial and spectral relationships among panchromatic and multispectral images. In recent years, the fast development of artificial intelligence (AI) and deep learning (DL) has significantly enhanced the development of pan-sharpening techniques. However, this field lacks a comprehensive overview of recent advances boosted by the rise of AI and DL. This paper provides a comprehensive review of a variety of pan-sharpening methods that adopt four different paradigms, i.e., component substitution, multiresolution analysis, degradation model, and deep neural networks. As an important aspect of pan-sharpening, the evaluation of the fused image is also outlined to present various assessment methods in terms of reduced-resolution and full-resolution quality measurement. Then, we conclude this paper by discussing the existing limitations, difficulties, and challenges of pan-sharpening techniques, datasets, and quality assessment. In addition, the survey summarizes the development trends in these areas, which provide useful methodological practices for researchers and professionals. Finally, the developments in pan-sharpening are summarized in the conclusion part. The aim of the survey is to serve as a referential starting point for newcomers and a common point of agreement around the research directions to be followed in this exciting area. This work was supported in part by the Natural Science Foundation of China (61901246), the China Postdoctoral Science Foundation, China Grant (2019TQ0190, 2019M662432), the Scientific Research Leader Studio of Ji’nan (2021GXRC081), and Joint Project for Smart Computing of Shandong Natural Science Foundation, China (ZR2020LZH015). Amir Hussain acknowledges the support of the UK Engineering and Physical Sciences Research Council (EPSRC)-Grants Ref. EP/M026981/1, EP/T021063/1, EP/T024917/1. Hui Yu acknowledges the support of Royal Society, UK (NIF/R1/180909). J. Del Ser would like to thank the Spanish Centro para el Desarrollo Tecnologico Industrial (CDTI, Ministry of Science and Innovation) through the “Red Cervera” Programme (AI4ES project), as well as by the Basque Government, Spain through the ELKARTEK program and the Consolidated Research Group MATHMODE (Ref. IT1456-22).

Herein, we report the systematic investigation of stereopure phosphorothioate (PS) and phosphoryl guanidine (PN) linkages on siRNA-mediated silencing. The incorporation of appropriately positioned and configured stereopure PS and PN linkages to N-acetylgalactosamine (GalNAc)-conjugated siRNAs based on multiple targets (Ttr and HSD17B13) increased potency and durability of mRNA silencing in mouse hepatocytes in vivo compared with reference molecules based on clinically proven formats. The observation that the same modification pattern had beneficial effects on unrelated transcripts suggests that it may be generalizable. The effect of stereopure PN modification on silencing is modulated by 2′-ribose modifications in the vicinity, particularly on the nucleoside 3′ to the linkage. These benefits corresponded with both an increase in thermal instability at the 5′-end of the antisense strand and improved Argonaute 2 (Ago2) loading. Application of one of our most effective designs to generate a GalNAc-siRNA targeting human HSD17B13 led to ∼80% silencing that persisted for at least 14 weeks after administration of a single 3 mg/kg subcutaneous dose in transgenic mice. The judicious use of stereopure PN linkages improved the silencing profile of GalNAc-siRNAs without disrupting endogenous RNA interference pathways and without elevating serum biomarkers for liver dysfunction, suggesting they may be suitable for therapeutic application.

BACKGROUND/PURPOSE: Toothpaste plays an important role in brushing teeth to maintain oral hygiene and health. The purpose of this study was to develop a new toothpaste containing surface nanocrystal-rich dicalcium phosphate anhydrous (DCPA) powder and to investigate its effect on tooth samples. MATERIALS AND METHODS: The innovative toothpaste (REALCaP®/Group R) was compared with two commercial toothpastes (BioRepair®/Group B and Sensodyne®/Group S). Brushing cycle tests were performed on bovine tooth slices coated with individual toothpaste and a control group without toothpaste (Group C). Microhardness, roughness, surface structure observation, and X-ray diffraction (XRD) were performed on cycle days 4, 7, and 14 to analyze the impact of the toothpastes on tooth samples. REULTS: Microhardness in the Group R was higher than that of the other groups regardless of the cycle days. Roughness in the Group R increased on days 4 and 7 but decreased on day 14. Roughness in the groups S and B increased with days. Microstructural observation revealed that most exposed dentinal tubules had been sealed in the Group R on day 14. Overlay thickness in the Group R was significantly higher than that in the groups S and B on days 4, 7, and 14. XRD analysis showed no hydroxyapatite (HA) peak in the Group S. The HA peak in the Group R was higher than that in the Group B on day 14. CONCLUSION: The innovative toothpaste has better properties than the commercially available products in terms of microhardness, roughness, and effectiveness in sealing dentinal tubules.

Chinese Named Entity Recognition (NER) is an essential task in natural language processing, and its performance directly impacts the downstream tasks. The main challenges in Chinese NER are the high dependence of named entities on context and the lack of word boundary information. Therefore, how to integrate relevant knowledge into the corresponding entity has become the primary task for Chinese NER. Both the lattice LSTM model and the WC-LSTM model did not make excellent use of contextual information. Additionally, the lattice LSTM model had a complex structure and did not exploit the word information well. To address the preceding problems, we propose a Chinese NER method based on the deep neural network with multiple ways of embedding fusion. First, we use a convolutional neural network to combine the contextual information of the input sequence and apply a self-attention mechanism to integrate lexicon knowledge, compensating for the lack of word boundaries. The word feature, context feature, bigram feature, and bigram context feature are obtained for each character. Second, four different features are used to fuse information at the embedding layer. As a result, four different word embeddings are obtained through cascading. Last, the fused feature information is input to the encoding and decoding layer. Experiments on three datasets show that our model can effectively improve the performance of Chinese NER.

KRAS is one of the most commonly mutated oncogenes in cancers and therapeutics directly targeting the KRas have been challenging. Among the different known mutants, KRasG12C has been proved to be successfully targeted recently. Several covalent inhibitors selectively targeting KRasG12C have shown promising efficacy against cancers harboring KRASG12C mutation in clinical trials and AMG510 (sotorasib) has been approved for the treatment of KRASG12C-mutated locally advanced or metastatic non-small cell lung cancer. However, the overall responsive rate of KRasG12C inhibitors was around 50% in patients with non-small cell lung cancer and the efficacy in patients with colorectal cancer or appendiceal cancer appears to be less desirable. It is of great importance to discover biomarkers to distinguish patients who are likely benefitted. Moreover, adaptive resistance would occur inevitably with the persistent administration like other molecularly targeted therapies. Several combinatorial regimens have been studied in an effort to potentiate the efficacy of KRasG12C inhibitors in preclinical settings. This review summarized the recent progress of covalent KRasG12C inhibitors with a focus on identifying biomarkers to predict or monitor the efficacy and proposing rational drug combinations based on elucidation of the mechanisms of drug resistance.

Amoxicillin resistance in Helicobacter pylori is mainly associated with mutations in penicillin-binding protein-1A (PBP-1A). However, the specific amino acid substitutions in PBP-1A that confer amoxicillin resistance in H. pylori remain to be investigated.This study aimed to investigate the molecular mechanism underlying amoxicillin resistance in patients with refractory H. pylori infection.Esophagogastroduodenoscopy (EGD) was performed in patients with persistent H. pylori infection after at least two courses of H. pylori eradication therapy between January-2018 to March-2021. Refractory H. pylori was cultured from the gastric biopsy specimens. Antibiotic susceptibility testing was conducted to determine the minimum inhibitory concentrations (MICs). Sequence analysis of pbp-1A was performed for amoxicillin-resistant strains.Thirty-nine successfully cultured isolates were classified as refractory H. pylori isolates, and seventeen isolates were resistant to amoxicillin (MIC0.125 mg/L). Sequence analysis of resistant strains showed multiple mutations in the C-terminal region of PBP-1A that conferred amoxicillin resistance in H. pylori. However, the number of PBP-1A mutations did not correlate with the high MICs of amoxicillin-resistant isolates. Notably, some amino acid substitutions were identified in all Taiwanese isolates with history of eradication failure but not in published amoxicillin-susceptible strains, suggesting that the mutations may play a role in conferring antibiotic resistance to these strains.Our results show that amoxicillin resistance in refractory H. pylori is highly correlated with numerous PBP-1A mutations that are strain specific. Continuous improvements in diagnostic tools, particularly molecular analysis approaches, can help to optimize current antimicrobial regimens.