MICROPLASTIC FIBER ACCUMULATION IN SOME WILD AND CULTURED SHRIMP SPECIES

This study was conducted to examine the microplastic fiber abundance and its characteristics in two wild and two cultured shrimp species collected at coastal areas in Hoai Nhon district, Binh Dinh Province. A total of 84 individuals of four shrimp species, Litopenaeus vannamei, Penaeus monodon, Metapenaeus ensis, and Penaeus semisulcatus were collected for analysis. All shrimp specimens were dissected to remove the digestive tracts, which were then treated with 10% KOH to collect microplastic fibers by filtering. The microplastic fiber concentrations varied from 1.96 ± 0.09 to 19.33 ± 10.82 fibers/specimen or 0.20 ± 0.12 to 2.26 ± 1.26 fibers/g of wet body weight. The abundance of fibers in the wild shrimps (Penaeus semisulcatus and Metapenaeus ensis) was higher than in the cultured shrimps (Penaeus monodon and Litopenaeus vannamei). Most fibers observed in the four shrimp species had lengths between 300 and 1500 μm, accounting for 78.72% to 92.82% of the total). White fibers were dominant (30.38%), followed by gray (11.87%), and green (10.60%)

Nonlinear analysis for proposing limit state criteria of reinforced concrete road bridge superstructures

In the research of long-time operating road bridge superstructures, it should note that when the internal forces in the beam elements reach specific values, the stiffness of the cross-section of these elements should decrease. Besides that, if there are damaged places in the beam-element of the road bridge superstructures, the element could not work normally, and the redistribution of internal forces between elements in the whole system would happen. This phenomenon was not taken into account in the initial design calculation. In practice, it shows that many road bridges are subjected to greater loads than the calculated loads in the design process, but they still normally operate. This article proposes the other limit state criteria in evaluating the load capacity reserve of road-bridge superstructures using nonlinear analysis based on nonlinear deformational models of modern construction codes. The proposed calculation procedure is established to explain the load capacity reserve of long-time operating road bridge superstructures in the case of the lack of experimental evaluation. From the obtained results, the suitable limit state criteria for road bridge superstructures are suggested, and the conclusions about the accuracy of the proposed approach of nonlinear structural analysis are recommended

Effects of different fibre sources in pig diets on growth performance, gas emissions and slurry characteristics

The effects of different fibre sources in pig diets on growth performance, ammonia (NH3), hydrogen sulphide (H2S), greenhouse gas (GHG) emissions and slurry characteristics was studied on 20 crossbred pigs [Duroc x F1 (Landrace x Yorkshire)]. The experimental diets included one low-fibre (LF) diet without maize distiller’s dried grains with solubles (DDGS), brewer’s grain (BG) and coconut cake (CC) and 3 high-fibre (HF) diets with maize DDGS or BG or CC. The experiment was conducted according to a completely randomized design with 5 replications and lasted 62 days. In the growing period and the overall, pigs fed diets LF and HF-DDGS had higher average daily gain (ADG) compared to pigs fed diets HF-BG and HF-CC (P 0.05), while N and P excretions (g/head/day) were greater for diet HF-CC than for diet LF (P < 0.05). The CO2 emission was greater for diets HF-BG and HF-CC than for diets LF and HF-DDGS (P 0.05). In both periods, CH4 emission was lower in diet LF than in diet HF-BG and HF-CC (P < 0.05), while NH3 emission was higher for pigs fed diet LF than pigs fed HF-BG and HF-CC (P < 0.05). The H2 S emission was not affected by diets in both periods. In conclusion, different fibre sources in pig diets may be a practical method to alter growth performance, slurry characteristics and NH3, GHG emissions

High school administrators' and teachers' perceptions of their educational action research skills

Educational action research has attracted significant attention from teacher-researchers and school administrators in recent years due to the method's effectiveness in teaching practices. Besides, educational action research skills are regarded as one of the essential aspects of doing action research. The present study aims to examine administrators' and teachers' perceptions of their educational action research skills; compare educational action research skills between the trained and the untrained groups and between the group that conducted the research and the group that did not. Quantitative research was used in this research. The study used the 11-item scale to survey 255 respondents (16 administrators and 239 teachers) from eleven high schools in Binh Duong province, Vietnam. The descriptive analysis was used to assess perceptions of high school administrators and teachers on their educational action research skills. Our results indicate that administrators and teachers assess their educational action research skills at very good. The trained group's educational action research skills are higher than the untrained group. Educational action research skills of the group conducted research are higher than the group that did not. The present findings provide more information on educational action research among administrators and teachers in Binh Duong province. Educational action research training programs, workshops, and educational policies should be implemented to reinforce and promote educational action research skills

The pedagogical training management of gifted high school teachers in the region of Red River Delta based on a competency approach

Pedagogical training for teachers is always an important issue of every education system. Teachers impart knowledge, give academic advice to students, and assist students in applying knowledge to develop society. This study investigated the gifted high school teacher pedagogical training management in the region of the Red River Delta according to the competency approach. Based on the available data, the research indicated three main things: (i) Professional pedagogical competence of gifted high school teachers; (ii) Pedagogical training activities for gifted high school teachers; (iii) Management of pedagogical training activities for gifted high school teachers. This study conducted a survey of 547 departmental and school managers in gifted high school teachers in nine provinces in Red River Delta, including Hanoi, Ha Nam, Thai Binh, Nam Dinh, Hai Duong, Hung Yen, Bac Ninh, Quang Ninh, and Vinh Phuc. These findings are only preliminary research, and they will be an important basis for proposing management solutions to improve the effectiveness of pedagogical training activities for gifted high school teachers

Geometrically nonlinear buckling analysis of truss with length imperfection subjected to mechanical and thermal load using hybrid FEM

This paper presents a novel hybrid FEM-based approach to establish the mathematical model for solving the nonlinear buckling problem of truss systems with length imperfection under mechanical and thermal load. due to constant temperature change-based hybrid FEM. The proposed approach deals with establishing hybrid types of truss elements, including perfect truss elements without thermal deformation and truss elements with length imperfection and thermal deformation. The equilibrium equation of both truss elements is established based on compatibility relationships considering geometric nonlinearity. The hybrid global equilibrium equations of truss systems are developed by assembling constructed perfect truss elements without thermal deformation and truss elements with length imperfection and thermal deformation. The incremental-iterative algorithm based on the arc-length method is used to establish calculation programs to solve the hybrid global equilibrium equation for investigating the geometrically nonlinear buckling behavior of the truss system. The numerical test is presented to investigate the buckling and post-buckling behavior of truss systems having some elements with length imperfection under thermal and mechanical load

Musculoskeletal Pain and Work-related Risk Factors among Waste Collectors in Hanoi, Vietnam: A Cross-sectional Study

BACKGROUND: Musculoskeletal disorders (MSDs) are prevalent among waste collectors (WCs) in developing countries. AIM: This study aimed to investigate the prevalence of MSDs and the factors associated with the risk of persistent musculoskeletal pain among WCs in Hanoi, Vietnam. METHODS: A cross-sectional survey was utilized to study 468 WCs in 2017. The Örebro Musculoskeletal Pain Questionnaire and a questionnaire on demographic and work conditions were used to collect data. Descriptive and multivariate logistics regression analyzes were applied at a significance level of 0.05 to examine the factors related to the risk of persistent pain. FINDINGS: About 74.4% of the participants of this study experienced MSDs in at least one body region and 9.4% reported MSDs in all 10 body sites. The lower back was reported to be the most affected followed by the neck and shoulders. The risk of persistent musculoskeletal pain was significantly associated with age (odds ratio (OR) = 2.31, confidence interval (CI) = 1.05–5.09), gender (OR = 3.29, CI = 1.28–8.44), work hours (OR = 2.35, CI = 1.12–4.92), work shift (OR = 0.48, CI = 0.26–0.92), duration of poor postures of the neck (OR = 0.31, CI = 0.13–0.76), bent back (OR = 0.4 CI = 0.18–0.92) and for medial rotation (OR = 3.01, CI = 1.42–6.36), carrying heavy objects (OR = 2.94, CI = 1.15–7.48), and experience of work dissatisfaction (OR = 3.31, CI = 1.46-7.52), stress (OR = 7.14, CI = 3.14–16.24), or anxiety (OR = 6.37, CI = 3.07–13.21). CONCLUSIONS: High prevalence of MSDs among WCs and its association with self-assessed unfavorable work postures and work-related stress implies the need of mechanical and social support at work for WC to prevent the development of MSDs and persistent pain

Novel exopolysaccharide produced from fermented bamboo shoot-isolated Lactobacillus fermentum

This study aimed at providing a route towards the production of a novel exopolysaccharide (EPS) from fermented bamboo shoot-isolated Lactobacillus fermentum. A lactic acid bacteria strain, with high EPS production ability, was isolated from fermented bamboo shoots. This strain, R-49757, was identified in the BCCM/LMG Bacteria Collection, Ghent University, Belgium by the phenylalanyl-tRNA synthetase gene sequencing method, and it was named Lb. fermentum MC3. The molecular mass of the EPS measured via gel permeation chromatography was found to be 9.85 × 104 Da. Moreover, the monosaccharide composition in the EPS was analyzed by gas chromatography–mass spectrometry. Consequently, the EPS was discovered to be a heteropolysaccharide with the appearance of two main sugars—D-glucose and D-mannose—in the backbone. The results of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance spectroscopy analyses prove the repeating unit of this polysaccharide to be [→6)-β-D-Glcp-(1→3)-β-D-Manp-(1→6)-β-D-Glcp-(1→]n, which appears to be a new EPS. The obtained results open up an avenue for the production of novel EPSs for biomedical applications

Synthesis of cuprous oxide nanocubes combined with chitosan nanoparticles and its application to p-nitrophenol degradation

For the first time, cuprous oxide nanocubes (Cu2O NCBs) were successfully combined with chitosan nanoparticles (CS NPs) to generate Cu2O NCBs/CS NPs composites material with highly optical property and photocatalytic activity using a simple and eco-friendly synthetic approach at room temperature for 30 min. The synthesized Cu2O NCBs NPs/CS NPs were determined characterizations by Ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), X – ray Diffraction (XRD),&nbsp; Transmission Electron Microscope (TEM) and Energy-dispersive X-ray spectroscopy (EDX). Results show that the Cu2O NCBs/CS NPs composites have an average particle size of ~3-5 nm; in which, Cu2O has the form of nanocubes (Cu2O NCBs) with size ~3-4 nm and chitosan nanoparticles with spherical shape (CS NPs) with size ~4-5 nm. In addition, the percent (%) composition of elements present in Cu2O NCBs/CS NPs composites material have been obtained respective: Cu (23.99%), O (38.18%), and C (33.61%). Moreover, Cu2O NCBs/CS NPs composites material was also investigated for photocatalytic activity applied in p-nitrophenol degradation. The obtained results showed that the catalytic capability of Cu2O NCBs/CS NPs for p-nitrophenol reduction reached the highest efficiency &gt;55% in the treatment time of 25 min, and this efficiency was higher than that result of using ZnO@chitosan nanoparticles (ZnO@CS NPs) catalyst under the same conditions for comparison

Decoding the capability of Lactobacillus plantarum W1 isolated from soybean whey in producing an exopolysaccharide

This study aims at producing exopolysaccharides (EPS) from a lactic acid bacterial strain. The soybean whey-isolated Lactobacillus plantarum W1 (EPS-W1), which belongs to genus Lactobacillus, is identified using the phenylalanyl-tRNA sequencing method. Of all the examined strains, R-49778 (as numbered by BCCM/LMG Bacteria Collection, Ghent University, Belgium) showed the highest capability of producing exopoly-saccharides. Structural characterization revealed a novel exopolysaccharide consisting of repeating units of -> 6)-D-Glcp-(1 ->; -> 3)-D-Manp-(1 ->; -> 3)-6-Glcp-(1 -> and a branch of -> 6)-D-Manp-(1 ->; -> 2)-D-Glcp-(1 ->. This discovery opens up avenues for the production of EPS for food industries, functional foods, and biomedical applications