141 research outputs found

    Determining the content of toxic elements (Pb, Cd, and As) in herbal plants collected from different sites in northern Vietnam

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    Plants might contain heavy metals from the surrounding polluted environment. Medicinal herb and plants, commonly used in Vietnam, may pose a risk to public health when polluted with heavy metals such as Pb, Cd and As. This study aims to investigate the content of Pb, Cd, and As in five selected herb plants (Phyllanthus urinaria L., Plantago asiatica L., Eleusine indica L., Wedelia chinensis (Osbeck) Merr, and Artemisia vulgaris L.). The samples were collected from natural sites in some provinces in northern Vietnam. The concentrations of Pb, Cd, and As were determined by the Inductively coupled plasma mass spectrometry (ICP-MS) method. The content of Pb, Cd and As was 0.247 ÷ 32.080 mg kg-1, 0.000 ÷ 1.099 mg kg-1, 0.000 ÷ 2.261 mg kg-1, respectively. A total of 50 out of the 58 investigated samples had concentrations of Pb, Cd, As lower than the permissible values of the World Health Organization (WHO). The remaining samples had contents of Pb or Cd or As significantly higher than the permissible limit defined by WHO.Thực vật có thể bị ô nhiễm do hấp thụ kim loại nặng từ môi trường ô nhiễm xung quanh. Các loại cây thảo dược được sử dụng phổ biến làm thuốc chữa bệnh ở Việt Nam. Chúng có thể gây nguy hiểm cho sức khỏe cộng đồng khi bị ô nhiễm kim loại nặng (Pb, Cd…vv.). Nghiên cứu này nhằm điều tra hàm lượng Pb, Cd và As trong năm loại cây thảo dược (cây Diệp Hạ Châu, cây Mã Đề, cây Cỏ Mần Trầu, cây Sài Đất và cây Ngải Cứu). Các mẫu cây này được lấy từ các địa điểm mọc tự nhiên ở một số tỉnh khác nhau thuộc khu vực miền bắc Việt Nam. Hàm lượng của Pb, Cd, và As được xác định bằng phương pháp ICP-MS. Hàm lượng Pb, Cd và As trong các mẫu phân tích lần lượt nằm trong khoảng là 0.247 ÷ 32.080 mg. Kg-1, 0.000 ÷ 1.099 mg. Kg-1, 0.000 ÷ 2.261 mg. Kg-1. 50 trên 58 mẫu phân tích có hàm lượng Pb, Cd, As thấp hơn giới hạn cho phép do tổ chức y tế thế giới (WHO) quy định. Có 8 trên 58 mẫu cây phân tích có hàm lượng Pb hoặc, Cd hoặc As cao hơn tiêu chuẩn giới hạn của WHO

    Conservation of Natural and Cultural Heritage in the Huong Son Complex of Natural Beauty and Historical Monuments, Northern Vietnam

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    The Huong Son Complex has long been recognised as an important sacred landscape in Vietnam due to its spiritual and cultural values. The area also retains many aesthetic and biological values. Unfortunately, its cultural and natural treasures are currently at risk due to anthropogenic impacts, mainly associated with increased spiritual tourist activities. Some urgent solutions have been implemented, but they give priority to protecting cultural values and sometimes conflict with nature conservation efforts. This problem was encountered during our recent bat conservation research in Huong Son. Our preliminary findings revealed symbiotic relationships between natural and cultural heritage in Huong Son; thus, linking nature and culture in conservation planning and management is critical for the sustainable development of the site. However, the application of this approach in Huong Son, and other sacred places in Vietnam, is challenged by gaps in basic research and the inadequate attention of local stakeholders

    Magnetic field assisted melt–spinning Nd-Fe-B ribbons and anisotropic bonded NdFeB magnets prepared thereof

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    The magnetic-field-assisted melt-spinning (FAMS) Nd10.5Fe72Co11B6.5 ribbons were spun in an external magnetic field of 3 kG. The prepared ribbons were ball-milled in xylene solvent for 30 minutes followed by adding in and mixing with the high-temperature binder HTB-1 (3 wt%) for further 10 minutes. The mixed powder was dried and in-mold aligned in a magnetic field of 18 kOe and hot-compacted at 200 oC. The parameters of the FAMS ribbon preparation, ball-milling process, hot-compaction and anisotropic bonded magnets’ fabrication were optimized leading to the magnet’s energy product (BH)max of 10 MGOe. The microstructure and magnetic properties of prepared ribbons and bonded magnets will be discussed in details

    Investigating the elements influencing the psychological issues of reform school students

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    Reformatory students are those whose deviant behaviors and habits prevent them from receiving education under normal educational conditions. These students frequently lead a careless, undisciplined lifestyle, being unwilling to work and learn eager to play and demanding. Therefore, when they are admitted to reformatories with severe study and lifestyle requirements, they have great psychological difficulty adjusting to their new environment. Students’ psychological issues in adapting to reformatory learning and living regimes are difficult and psychological deficits make it challenging for students to adapt to reformatory learning and living conditions. In Vietnam, 665 students from reformatory schools were polled to determine the causes of psychological issues. According to the findings, a variety of elements contribute to students’ psychological difficulties. Individual student conditions such as health, awareness, attitudes and actions as well as inappropriate habits, living without goals or aspirations, etc. are on the subjective side of the equation. On the objective side are the students’ conditions, family, education and psychological obstacles brought on by less-than-ideal circumstances which will make it more difficult for community students to adapt. Both the new school and society must pay more attention to reformatory students in order to establish the conditions necessary for successful integration into the new school and ultimate readmission into society for these students

    Long-term outcomes of primary cardiac malignant tumors: Difference between African American and Caucasian population

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    BACKGROUND: The survival outcome for primary cardiac malignant tumors (PMCTs) based on race has yet to be fully elucidated in previously published literature. This study aimed to address the general long-term outcome and survival rate differences in PMCTs among African Americans and Caucasian populations. METHODS: The 18 cancer registries database from the Surveillance, Epidemiology, and End Results (SEER) Program from 1975 to 2016 were utilized. Ninety-four African American (AA) and 647 Caucasian (CAU) patients from the SEER registry were available for survival analysis. The log-rank test was used to compare the difference in mortality between two populations and presented by the Kaplan-Meier curves. A multivariate Cox proportional hazards regression was used to determine the independent predictors of all-cause mortality. RESULTS: The overall 30-day, 1-year, and 5-year survival rates were 74%, 44.3%, and 16.6%, respectively, with a median survival of 10 months. There was no significant difference in survival rate between the two races (p-value = 0.55). The 1-year survival rate improved significantly during the study timeline in the AA population (13.3% during 1975-1998, 40.9% during 1999-2004, 50% during 2005-2010, and 59.7% during 2011-2016, p-value = 0.0064). Age of diagnosis, type of tumor, disease stage, and chemotherapy administration are the main factors that predict survival outcomes of PMCT patients. Interactive nomogram was developed based on significant predictors. CONCLUSIONS: PMCTs have remained one of the most lethal diseases with poor survival outcome. Survival rate improved during the timeline in AA patients, but in general, racial differences in survival outcome were not observed

    Attitudes toward Self-Disclosure on Facebook: A Review of Perception, Emotion and Behavior in University Students

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    A number of social networking platforms have emerged as a result of the development of information and communication technology which have become increasingly user-friendly and full with valuable features. The social networking site with most users is Facebook. Teenagers, particularly college students use Facebook most frequently to study, gain information, entertain themselves and connect with others through self-disclosing personal information on the Facebook profile page. This quantitative study aimed to analyze the attitude of pedagogical students regarding self-disclosure on Facebook as represented through cognition, emotion and behavior concerning academic achievement. The survey was completed by 535university student’s majority in pedagogy. There were 41 students who used it for less than three years between three to five years by 218 students and 276 students who use it more than five years. The questionnaire was self-reported by participants to assess university students' attitudes toward self-disclosure on Facebook. The results indicate that pedagogical students with excellent academic achievement and more than five years of Facebook experience had the highest-level attitude toward self-disclosure on Facebook. The results indicate a positive relationship between cognition, emotion and influence factors students' Facebook attitudes. Future research on methods that enhance student positive disclosure can benefit from this study. Future research should examine how self-disclosure on Facebook relates to other aspects, such as Facebook usage time, financial state and perception of advantages and its disadvantages of Facebook in order to evaluate students' attitudes objectively

    Recent remarkable records reveal that Phia Oac-Phia Den Nature Reserve is a priority area for bat conservation in Northern Vietnam

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    AbstractThree short field surveys were conducted in the Phia Oac-Phia Den Nature Reserve to assess the species diversity and endemism of local bat fauna. In combination with data from a previous study, 24 bat species of 5 families, representing > 20% of the national bat diversity, were recorded in the study area. The occurrence of several bat species restricted to montane forests, that is, Murina chrysochaetes, Pipistrellus coromandra, and a potentially new species Rhinolophus cf. macrotis, suggests that Phia Oac is an important area for bat conservation in Vietnam and thus more comprehensive studies need to be performed

    One-pot preparation of alumina-modified polysulfone-graphene oxide nanocomposite membrane for separation of emulsion-oil from wastewater

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    In recent years, polysulfone-based nanocomposite membranes have been widely used for contaminated water treatment because they comprise properties such as high thermal stability and chemical resistance. In this study, a polysulfone (PSf) nanocomposite membrane was fabricated using the wet-phase inversion method with the fusion of graphene oxide (GO) and alumina (Al2O3) nanoparticles. We also showed that GO-Al2O3 nanoparticles were synthesised successfully by using a one-pot hydrothermal method. The nanocomposite membranes were characterised by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherms, energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and water contact angle. The loading of GO and Al2O3 was investigated to improve the hydrophilic and oil rejection of the matrix membrane. It was shown that by using 1.5 wt.% GO-Al2O3 loaded in polysulfone, ~74% volume of oil was separated from the oil/water emulsion at 0.87 bar and 30 min. This figure was higher than that of the process using the unmodified membrane (PSf/GO) at the same conditions, in which only ~60% volume of oil was separated. The pH, oil/water emulsion concentration, separation time, and irreversible fouling coefficient (FRw) were also investigated. The obtained results suggested that the GO-Al2O3 nanoparticles loaded in the polysulfone membrane might have potential use in oily wastewater treatment applications

    THE EFFECTS OF DRYING TEMPERATURE ON THE STRUCTURE AND CORROSION RESISTANCE OF Cr3+-BASED CONVERSION COATINGS ON ZINC-COATED STEEL SURFACE

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    In this paper, we present results of drying temperature influence on the structure and corrosion  resistance of  Cr(III)–based conversion coatings on the surface of zinc-coated steel. The results show that the quality of Cr(III)–based conversion coatings is strongly influenced by the drying temperature, the appropriate drying temperature is about 80 oC, and drying at higher temperatures will reduce corrosion resistance durability and raise the cost of the production process
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