Search

Objectives: Recently, the definition of extensively drug-resistant TB (XDR-TB) has been revised. In this study, we conducted a descriptive and retrospective study to determine the prevalence of XDR-TB in a Chinese multidrug-resistant TB (MDR-TB) cohort. Methods: Broth microdilution method was performed to determine in vitro susceptibilities of Mycobacterium tuberculosis (MTB) isolates to (FQs), bedaquiline (BDQ) and linezolid (LZD). The putative drug target genes conferring drug resistance were screened by DNA sequencing. Results: A total of 425 MDR-TB isolates were included from 13 pilots in China. LZD and BDQ resistance were noted in 30 (7.1%) and 10 (2.4%) isolates. On the basis of latest definitions, 114 (26.8%) were MDR-TB, 282 (66.4%) were pre-XDR-TB, and 29 (6.8%) were XDR-TB. Among 311 FQ-resistant isolates, 265 harbored genetic mutations within QRDRs. The most common mutations were observed at codon 94 of gyrA, accounting for 47.2% of FQ-resistant MTB isolates. Only mutations within the Rv0678 gene were found to confer BDQ resistance in our cohort, conferring 40.0% of BDQ resistance. For LZD resistance, 53.3% of LZD-resistant isolates carried genetic mutations in rplC or 23S rRNA. The most frequent mutation was Cys154Arg in the rplC gene. In addition, we recorded two MDR-TB patients with resistance to both BDQ and LZD, of which one patient experienced continuous positive culture of MTB despite inclusion of efficacious moxifloxacin. Conclusion: Our results demonstrate that the low prevalence of XDR-TB holds great promise for MDR-TB treatment with WHO-endorsed regimens containing BDQ-LZD combination, whereas the high prevalence of FQ-resistance in MDR-TB patients warrants national attention. [ABSTRACT FROM AUTHOR]

The simplicity of structure and the no mode-hop tuning characteristic are of crucial importance for external-cavity diode laser applied in the field of experiment and engineering. A new and enhanced structure for mirror-grating Littrow-type external-cavity diode laser (ECDL) is proposed in this article. On the basis of this external cavity diode laser, a large mode-hop-free tuning range can be obtained and the direction of the output beam remains almost unchanged when the laser is tuned. We can tune the laser over a continuous range reaches 4.34 nm and the lateral displacement of output beam is only 0.033 mm at 805 nm when the initial length of external cavity is 12.82 mm. [ABSTRACT FROM AUTHOR]

• Mechanism of high frequency harmonic resonance of Luxi VSC-HVDC project is analyzed. • Time delay and system impedance will influence the high frequency harmonic resonance. • A method to suppress the high frequency harmonic resonance is proposed. This paper introduces the basic situation of high frequency harmonic resonance in Guangxi on April 10, 2017, which is based on the Luxi back-to-back voltage source converter based high voltage direct current transmission (VSC-HVDC) project in China. Firstly, the harmonic amplification mechanism and its key links in the event are analyzed in detail and verified by simulation. Secondly, the relationship among high frequency harmonic resonance, voltage feedforward control loop and system harmonic impedance is obtained, and the formulas among voltage feedforward control parameters, system harmonic impedance and high frequency harmonic resonance frequency amplitude are deduced. Then, a method to suppress high frequency harmonic resonance by adding a reasonably filter to the voltage feedforward control loop is proposed. Finally, the effectiveness of the proposed method in this paper is verified by simulation and field operation. [ABSTRACT FROM AUTHOR]

Three‐dimensional unmanned aerial vehicle (UAV) oblique photogrammetric data were used to infer mountainous gravel braided river lithofacies, lithofacies associations and architectural elements. Hierarchical architecture and lithofacies associations with detailed lithofacies characterizations were comprehensively described to document the architectural model, architectural element scale and gravel particle scale. (1) Nine lithofacies (i.e., Gmm, Gcm, Gcc, Gci, Gcl, Ss, Sm, Fsm and Fl) were identified and classified as gravel, sand and fine matrix deposits. These are typical depositional features of a mountainous dryland gravel‐braided river. (2) Three architectural elements were identified, including channel (CH), gravel bar (GB) and overbank (OB). CH can be further divided into flow channel and abandoned channel, while GB consists of Central Gravel bar (CGB) and Margin Gravel bar (MGB). (3) The gravel bar is the key architectural element of the gravel braided river, with its geological attributes. The dimensions of GBs and their particles are various, but exhibit good relationships with each other. The grain size of GB decreases downstream, but the dimensions of GB do not. The bank erosion affects the GB dimensions, whereas channel incision and water flow velocity influence the grain size of GB. The conclusions can be applied to the dryland gravel braided river studies in tectonically active areas. [ABSTRACT FROM AUTHOR]

Abstract: Magnetron sputtering deposition of Mo and Zr and subsequent annealing were conducted with the motivation to modify the surface hardness of Ti3SiC2. For Mo-coated Ti3SiC2, Si diffused outward into the Mo layer and reacted with Mo to form molybdenum silicides in the temperature range of 1000–1100°C. The MoSi2 layer, however, cracked and easily spalled off. For Zr-coated Ti3SiC2, Si also diffused outward to form Zr–Si intermetallic compounds at 900–1100°C. The Zr–Si compounds layer had good adhesion with Ti3SiC2 substrate, which resulted in the increased surface hardness. [Copyright &y& Elsevier]

Abstract: Magnetron sputtering deposition Cu and subsequent annealing in the temperature range of 900–1100°C for 30–60min were conducted with the motivation to modify the surface hardness of Ti3SiC2. Owing to the formation of TiC following the reaction Ti3SiC2 +3Cu→3TiC0.67 +Cu3Si, the surface hardness was enhanced from 5.08GPa to a maximum 9.65GPa. In addition, the surface hardness was dependent on the relative amount of TiC, which was related to Cu film thickness, heat treatment temperatures and durations of annealing. Furthermore, after annealing at 1000°C for 30min the Cu-coated Ti3SiC2 has lower wear rate and lower COF at the running-in stage compared with Ti3SiC2 substrate. The reaction was triggered by the inward diffusion of Cu along the grain boundaries and defects of Ti3SiC2. At low temperature and short annealing time, i.e. 900 or 1000°C for 30min, Cu diffused inward Ti3SiC2 and accumulated at the trigonal junctions first. At higher temperature of 1100°C or prolonging the annealing time to 60min, considerable amount of Cu diffused to Ti3SiC2 and filled up the grain boundaries leaving a mesh structure. [Copyright &y& Elsevier]

• WFQ-228 is more efficacious than LFX in isolates with specific mutations. • The bactericidal effect is more frequently observed in MFX-susceptible isolates. • The heterogeneity in MICs of isolates with different mutations is noted across FQs. WFQ-228 is a novel developed fluoroquinolone (FQ) displaying potent antimicrobial activity against various clinical isolates of pathogens, including FQ-resistant isolates. The aim was to comparatively analyze in vitro susceptibilities of WFQ-228, levofloxacin (LFX), and moxifloxacin (MFX) against Mycobacterium tuberculosis (MTB) isolates, especially with gyrA mutations. We selected a panel of 75 MTB isolates, consisting of 25 FQ-susceptible and 50 FQ-resistant isolates determined by conventional drug susceptibility testing. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of FQs to MTB isolates were assessed. MFX exhibited the most potent activity against FQ-susceptible MTB, demonstrating a MIC 50 of 0.031 mg/L, which was lower than that of LFX and WFQ-228. Against FQ-resistant MTB isolates, the MIC 50 of WFQ-228 was higher than that of MFX but lower than that of LFX. For WFQ-228, there was a significant overlap existing in the MIC distributions between the probable susceptible (PS) and probable resistant (PR) groups. Six out of 50 PR isolates were classified as susceptible based on a proposed critical concentration (CC) of 0.5 mg/L, yielding a poor sensitivity of 88.0%. These discordant isolates had GyrA substitution in Ala90Val, Ser91Pro, and Asp94Tyr. Additionally, MFX exhibited bactericidal activity against MTB isolates without gyrA mutations, which was significantly higher than that of isolates with gyrA mutations. WFQ-228 is more efficacious than LFX in isolates with specific mutations conferring low-level FQ resistance. The bactericidal effect is noted more frequently in FQ-susceptible isolates than FQ-resistant isolates for MFX. [ABSTRACT FROM AUTHOR]

Objective: The efficacy and safety of subxiphoid thoracoscopic thymectomy (SVATS) for early thymoma are unknown. The purposes of this meta-analysis were to evaluate the effectiveness and safety of SVATS for early thymoma, to compare it with unilateral intercostal approach video thoracoscopic surgery (IVATS) thymectomy, and to investigate the clinical efficacy of modified subxiphoid thoracoscopic thymectomy (MSVATS) for early anterior mediastinal thymoma. Methods: Original articles describing subxiphoid and unilateral intercostal approaches for thoracoscopic thymectomy to treat early thymoma published up to March 2023 were searched from PubMed, Embase, and the Cochrane Library. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were calculated and analyzed for heterogeneity. Clinical data were retrospectively collected from all Masaoka stage I and II thymoma patients who underwent modified subxiphoid and unilateral intercostal approach thoracoscopic thymectomies between September 2020 and March 2023. The operative time, intraoperative bleeding, postoperative drainage, extubation time, postoperative hospital stay, postoperative visual analog pain score (VAS), and postoperative complications were compared, and the clinical advantages of the modified subxiphoid approach for early-stage anterior mediastinal thymoma were analyzed. Results: A total of 1607 cases were included in the seven studies in this paper. Of these, 591 cases underwent SVATS thymectomies, and 1016 cases underwent IVATS thymectomies. SVATS thymectomy was compared with IVATS thymectomy in terms of age (SMD = − 0.09, 95% CI: −0.20 to − 0.03, I2 = 20%, p = 0.13), body mass index (BMI; SMD = − 0.10, 95% CI: −0.21 to − 0.01, I2 = 0%, p = 0.08), thymoma size (SMD = − 0.01, 95% CI: −0.01, I2 = 0%, p = 0.08), operative time (SMD = − 0.70, 95% CI: −1.43–0.03, I2 = 97%, p = 0.06), intraoperative bleeding (SMD = − 0.30. 95% CI: −0.66–0.06, I2 = 89%, p = 0.10), time to extubation (SMD = − 0.34, 95%CI: −0.73–0.05, I2 = 91%, p = 0.09), postoperative hospital stay (SMD = − 0.40, 95% CI: −0.93–0.12, I2 = 93%, p = 0.13), and postoperative complications (odds ratio [OR] = 0.94, 95% CI: 0.42–2.12, I2 = 57%, p = 0.88), which were not statistically significantly different between the SVATS and IVATS groups. However, the postoperative drainage in the SVATS group was less than that in the IVATS group (SMD = − 0.43, 95%CI: −0.84 to − 0.02, I2 = 88%, p = 0.04), and the difference was statistically significant. More importantly, the postoperative VAS was lower in the SVATS group on days 1 (SMD = − 1.73, 95%CI: −2.27 to − 1.19, I2 = 93%, p < 0.00001), 3 (SMD = − 1.88, 95%CI: −2.84 to − 0.81, I2 = 97%, p = 0.0005), and 7 (SMD = − 1.18, 95%CI: −2.28 to − 0.08, I2 = 97%, p = 0.04) than in the IVATS group, and these differences were statistically significant. A total of 117 patients undergoing thoracoscopic thymectomy for early thymoma in the Department of Thoracic Surgery of the Second Hospital of Jilin University were retrospectively collected and included in the analysis, for which a modified subxiphoid approach was used in 42 cases and a unilateral intercostal approach was used in 75 cases. The differences between the two groups (MSVATS vs. IVATS) in general clinical characteristics such as age, sex, tumor diameter, Masaoka stage, Word Health Organization (WHO) stage, and intraoperative and postoperative conditions, including operative time, postoperative drainage, extubation time, postoperative hospital stay, and postoperative complication rates, were not statistically significant (p > 0.05), while BMI, intraoperative bleeding, and VAS on postoperative days 1, 3, and 7 were all statistically significant (p < 0.05) in the MSVATS group compared with the IVATS group. Conclusion: The meta-analysis showed that the conventional subxiphoid approach was superior in terms of postoperative drainage and postoperative VAS pain scores compared with the unilateral intercostal approach. Moreover, the modified subxiphoid approach had significant advantages in intraoperative bleeding and postoperative VAS pain scores compared with the unilateral intercostal approach. These results indicate that MSVATS can provide more convenient operation conditions, a better pleural cavity view, and a more complete thymectomy in the treatment of early thymoma, indicating that is a safe and feasible minimally invasive surgical method. [ABSTRACT FROM AUTHOR]

Extracellular adenosine (Ade) interacts with cells by two pathways: by activating cell surface receptors at nanomolar/micromolar concentrations; and by interfering with the homeostasis of the intracellular nucleotide pool at millimolar concentrations. Ade shows both cytotoxic and cytoprotective effects; however, the underlying mechanisms remain unclear. In the present study, the effects of adenosine-mediated ATP on cell viability were investigated. Adenosine treatment was found to be cytoprotective in the low intracellular ATP state, but cytotoxic under the normal ATP state. Adenosine-mediated cytotoxicity and cytoprotection rely on adenosine-derived ATP formation, but not via the adenosine receptor pathway. Ade enhanced proteasome inhibition-induced cell death mediated by ATP generation. These data provide a new pathway by which adenosine exerts dual biological effects on cell viability, suggesting an important role for adenosine as an ATP precursor besides the adenosine receptor pathway. [ABSTRACT FROM AUTHOR]

--This paper selects the whole microgrid system as the master and renewable energy, energy storage, and load as the game's slave. It builds a master-slave game optimization model for coordinating the microgrid's source-network-load-storage. The master's goal in the microgrid game is to minimize the overall operation cost. The slave in the renewable energy game aims to minimize the operation cost of renewable energy while considering penalties for wind and PV curtailment. The slave in the energy storage game focuses on optimizing energy storage regulation performance and considers overcharge/discharge risks. Meanwhile, in the load game, the slave aims for the highest power quality and improves load power quality as much as possible while preserving demand response capability to enhance system flexibility. The case analysis shows after 45 games, all game participants can achieve Stackelberg equilibrium, effectively balancing multi-party benefits and improving safety and regulation capabilities of energy storage operations. The microgrid operation scheme based on this method maintains the existing microgrid operation mode and ensures safe and stable system operation. • A master-slave game optimization model for a microgrid is built. • A storage operation method considering the overcharge/overdischarge risk is proposed. • A flexible load operation method considering the power quality of load is proposed. • An operation method considering the penalty of wind and PV curtailment is proposed. • Different benefits among whole system and various subsystems are balanced. [ABSTRACT FROM AUTHOR]

Abstract: Proteasome inhibition has emerged as a novel approach to anticancer therapy. Numerous natural compounds, such as gambogic acid, have been tested in vitro and in vivo as anticancer agents for cancer prevention and therapy. However, whether gambogic acid has chemosensitizing properties when combined with proteasome inhibitors in the treatment of malignant cells is still unknown. In an effort to investigate this effect, human leukemia K562 cells, mouse hepatocarcinoma H22 cells and H22 cell allografts were treated with gambogic acid, a proteasome inhibitor (MG132 or MG262) or the combination of both, followed by measurement of cellular viability, apoptosis induction and tumor growth inhibition. We report, for the first time, that: (i) the combination of natural product gambogic acid and the proteasome inhibitor MG132 or MG262 results in a synergistic inhibitory effect on growth of malignant cells and tumors in allograft animal models and (ii) there was no apparent systemic toxicity observed in the animals treated with the combination. Therefore, the findings presented in this study demonstrate that natural product gambogic acid is a valuable candidate to be used in combination with proteasome inhibitors, thus representing a compelling anticancer strategy. [ABSTRACT FROM AUTHOR]

• A multi-layer mockup with uranium alloy disks and breeder pebble bed which represents real engineering design of HTBB has been setup. • Several neutronic responses such as fission reaction rate, plutonium producction rate, activation reaction rate and tritium production rate have been measured. • The C/E results show that calculations generally agree with experiments within 4% for tritium production rate. • The experiment has provided validation to the HTBB design, calculation code and nuclear data used in the simulations. A neutronic experiment has been performed using DT neutrons on a blanket mockup of the hybrid tritium breeding blanket (HTBB) at CAEP. As a backup blanket configuration for CFETR, HTBB design which uses uranium alloy, water coolant and ceramic breeder pebble bed has been proposed to obtain high tritium breeding ratio. The experiment has provided validation not only to the preliminary design of HTBB, but also to calculation code and nuclear data used in the simulations. Various neutron responses such as fission reaction rate, plutonium production rate, activation reaction rate and tritium production rate (TPR) have been measured. Numerical analyses were carried out with MCNP-4C code using ENDF/B-VII.1, TENDL-2017, IRDFF-v1.05 and FENDL3.1 nuclear data libraries. The comparisons between the calculation and experimental results show an agreement within about 10% for most of the measured quantities. The ratios of calculated to measured results (C/E) of tritium production rate are in 0.98–1.04 range which shows good agreement. [ABSTRACT FROM AUTHOR]