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Background and Objectives: Identification of pnemococcal serotypes and antimicrobial resistance provides helpful information for the use of suitable vaccines and antibiotics; however, very limited data is available on these issues in Vietnam. The present study aimed to find the serotype distribution and drug resistance patterns of Streptococcus pneumoniae isolated from unvaccinated children less than 5 years of age with pneumonia at a province in centre Vietnam. Materials and Methods: A total of 126 clinical pnemococcal strains isolated from unvaccinated children less than 5 years of age with pneumonia at the Nghe An province, Vietnam between Nov 2019 and Mar 2021. All strains were identified using conventional microbiological method, VITEK® 2 Compact system, specific PCR and sequencing. The serotypes and antimicrobial resistance patterns of pnemococcal strains were determined using the multiplex PCR assays and VITEK® 2 Compact system. Results: The results showed that, eight different pneumococcal serotypes were identified. The most common serotypes were 19F (67.46%), followed by 23F (10.32%), 19A (9.52%), 6A/B (3.17%), 15A (2.38%), 9V (3.17%), 11A (1.59%) and 14 (0.80%), respectively. More than half of the pneumococcal strains were non-susceptible to penicillin. The resistance rate to ceftriaxone and cefotaxime were 41.3% and 50.8%. The percentage of pneumococci strains resistant to clarithromycin, azithromycin, erythromycin, cotrimoxazole, tetracyclin, and clindamycin were more than 93% of all strains. All pneumococcal serotypes were highly resistant to clarithromycin, azithromycin, erythromycin, cotrimoxazole, and clindamycin. Conclusion: Our findings showed high antibiotic resistance rates of the strains causing pneumococcal pneumonia, mostly macrolide resistance, among unvaccinated children.

This study presents a tri-layer broadband metamaterial absorber that operates in the GHz range. The absorber was composed of a polyhedral iron-cobalt alloy/graphite nanosheet material arranged in a flat sheet with two punched-in rings for the top layer, a continuous FR-4 layer at the middle, and a continuous copper layer at the bottom. For the normal incidence of the electromagnetic wave, the proposed absorber demonstrated an exceptional broadband absorption in a frequency range of 7.9–14.6 GHz, revealing an absorption exceeding 90%. The absorption magnitude remains to be above 90% in a frequency range of 8–11.1 GHz for transverse-electric-polarized waves at incident angles up to 55°. For both the transverse-magnetic- and electric-polarized waves, the absorption exceeds 90% in a frequency range of 9.5–14.6 GHz. The physical mechanism behind the absorption properties is analyzed thoroughly through the electric and magnetic field distributions. The obtained results could contribute potentially to the development of microwave applications based on metamaterial absorbers, such as radar-stealth technology, electromagnetic shielding for health safety, and reduced electromagnetic interferences for high-performance communications and electronic devices.

To further develop Liupao tea products and enhance their flavor, this study investigated the effects of different fermentation methods on the aroma quality of Liupao tea. The aroma quality of Liupao tea was comprehensively analyzed using HS-SPME in combination with GC-Q-TOF-MS, electronic nose, and sensory evaluations. Electronic nose detection showed that the aroma fingerprints of Liupao tea samples with different fermentation methods were different. Sulfides, alcohols, ketones, and methyls were the main aroma categories affecting the aroma of the four groups of Liupao tea samples. GC-Q-TOF-MS analysis revealed significant differences in the composition of aroma components among the four fermentation methods of Liupao tea (p < 0.05). Furthermore, the total amount of aroma compounds was found to be highest in the group subjected to hot fermentation combined with the inoculation of Monascus purpureus (DMl group). Based on the OPLS-DA model, candidate differential aroma components with VIP > 1 were identified, and characteristic aroma compounds were selected based on OAV > 10. The key characteristic aroma compounds shared by the four groups of samples were 1,2,3-Trimethoxybenzene with a stale aroma and nonanal with floral and fruity aromas. The best sensory evaluation results were obtained for the DMl group, and its key characteristic aroma compounds mainly included 1,2,3-Trimethoxybenzene, nonanal, and cedrol. The results of this study can guide the development of Liupao tea products and process optimization. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The permeability coefficient of landslide mass, a key parameter in the study of reservoir landslides, is commonly obtained through in situ and laboratory tests; however, the tests are costly and subject to high variability, leading to potential biases. In this paper, a new method was proposed to inversely estimate the permeability coefficient of landslide layers using monitoring data of groundwater level (GWL). First, the landslide transient seepage simulation was conducted to generate sample data for permeability coefficients and GWL during a reservoir operation cycle. Second, using GWL data as input and permeability coefficient data as output, the least-square support vector machine (LSSVM) was trained with two optimization algorithms, the particle swarm optimization (PSO) algorithm and the whale optimization algorithm (WOA), to construct the nonlinear mapping relationship between simulated GWL and permeability coefficients. Third, the accurate permeability coefficients for landslide seepage simulation were inverted or predicted based on the monitored GWL. Finally, using the inverted permeability coefficients for landslide seepage simulation, we compared simulation results with actual monitored GWL and achieved good consistency. In addition, this paper compared the inversion effects of three different algorithms: the standard LSSVM, PSO-LSSVM, and WOA-LSSVM. This study showed that these three algorithms had good nonlinear fitting effects in studying landslide seepage fields. Among them, using the inversion values from PSO-LSSVM for landslide seepage simulation resulted in the smallest relative error compared to actual monitoring data. Within a single reservoir operation cycle, the simulated water level changes were also largely consistent with the monitored water level changes. The results could provide a reference to determine landslide permeability coefficients and seepage. [ABSTRACT FROM AUTHOR]

Abstract\n摘要\nPLAIN LANGUAGE SUMMARYThis study explored the effects of listening-based lexical focus-on-form (lexical FonF) on the acquisition and retention of morphologically complex words. One hundred eighty-two adult English learners with two levels of English proficiency (higher and lower proficiency) from a public university in mainland China were assigned to three different conditions: morphological instruction (MI), an experimental condition in which morphological instruction related to target words was provided in addition to a series of audio passages containing the target items; word meaning explanation (WME), an experimental condition in which explanations of the word meaning of target items were offered in addition to the listening activity; and one control condition (CT) in which learners were exposed only to the listening activity. The results indicated that lexical FonF led to more vocabulary gains than purely incidental FonF and that the MI condition significantly outperformed the WME condition in both the acquisition and retention of morphologically complex words. In addition, no interaction was detected between the preintervention proficiency level and word learning conditions.本研究探讨了基于听力的词形关注 (lexical FonF) 对语素复杂单词的习得和保持的影响。来自中国大陆一所公立大学的182名具有不同英语水平的成人英语学习者(高水平和低水平)被分配到三种不同的实验条件下: 在语素干预实验条件(MI)下, 学习者除了包含目标词的听力活动外, 还接受与目标词相关的语素规则讲解；在词义解释实验条件下(WME), 学习者除了包含目标词听力活动外, 还接受目标词的词义解释；在对照条件(CT)下, 学习者只进行包含目标词的听力活动。结果表明, 词形关注比纯粹的附带词形习得更有利于词汇学习, 而且在语素复杂单词的习得和保持方面, 语素干预效果明显优于词义解释。此外, 干预前的语言水平与单词学习条件之间并没有发现交互作用。This study looked at the effects of combining a meaning-focused listening activity and explicit vocabulary teaching (lexical FonF) on the acquisition and retention of morphologically complex words. One hundred eighty-two adult English learners with two levels of English proficiency (higher and lower proficiency) from a public university in mainland China were placed in three different conditions: morphological instruction (MI), an experimental condition in which learners were taught internal structure of target words in addition to a series of audio passages containing the target items; word meaning explanation (WME), an experimental condition in which explanations of the word meaning of target items were offered in addition to the listening activity; and one control condition (CT) in which learners only listened to a series of audio passages containing the target items. The results indicated that the combination of a meaning-focused listening activity and explicit vocabulary teaching led to more vocabulary gains than purely incidental vocabulary learning from a meaning-focused listening activity. In addition, the MI condition significantly outperformed the WME condition in both the acquisition and retention of morphologically complex words. The learners’ initial proficiency levels did not influence the impact of the intervention conditions. [ABSTRACT FROM AUTHOR]

Industrial-scale production of acetaldehyde relies heavily on homogeneous catalysts. Here, we used ethane as the feedstock and developed ZSM-5-supported PdO nanoparticles for the direct oxidation of ethane to acetaldehyde by utilizing O2 and CO. PdO nanoparticles clearly demonstrate effective activity and prevent the further deep oxidation of acetaldehyde. [ABSTRACT FROM AUTHOR]

Summary: In order to achieve efficiency extremum of power conversion independent of parameter values and operational mode, an adaptive dual‐controller on‐line efficiency optimization method is presented in this paper. Firstly, based on tri‐modal analysis for four‐switch buck‐boost (FSBB) converter, efficiency extremum analysis is given and existed for such this converter. Then, adaptive dual controller on‐line efficiency seeking algorithm is shown to adaptive two variables for efficiency optimization and output voltage regulation. Furthermore, perturb and observe detector is described to realize control variables decoupling of dual‐controller and to prevent the instability of the whole system during the algorithm tuning process and to improve the algorithm speed of the dual controller. The proposed method is model independent and does not depend on the circuit parameter values. The detail implement of algorithm and performance analysis is given, and the experimental platform and experimental results are put forward to verify the effectiveness of the algorithm. [ABSTRACT FROM AUTHOR]