75 research outputs found
LOẠI BỎ XANH METYLEN BẰNG PHƯƠNG PHÁP ĐIỆN DI LẮNG ĐỌNG KẾT HỢP VỚI VẬT LIỆU MnO2/GO
Graphene oxide (GO) was synthesized with the improved Hummer method and chemically modified with manganese dioxide (MnO2) to obtain an MnO2/GO composite. The properties of the composite material were evaluated via infrared spectroscopy, UV-Vis spectroscopy, scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, and image mapping. The parameters studied in the method of electrophoretic deposition (EPD) are pH, electrolysis potential, electrolysis time, sodium chloride concentration, and the mass of the composite. Under suitable experimental conditions, the EPD method provides a rate of colour removal and chemical oxygen demand (COD) of methylene at 99.64 and 85.85%. This result shows the potential of the EPD method coupled with MnO2/GO composite to remove organic pigments in the aqueous medium.Vật liệu graphen oxit (GO) được tổng hợp bằng phương pháp Hummer cải tiến và biến tính với mangan đioxit (MnO2) bằng phương pháp hóa học để thu được vật liệu tổ hợp MnO2/GO. Một số tính chất đặc trưng của vật liệu tổ hợp được đánh giá bằng phổ hồng ngoại, phổ UV-Vis, hiển vi điện tử quét kết hợp với quang phổ tán xạ năng lượng tia X và ảnh mapping. Các thông số trong phương pháp điện di lắng đọng (EPD) như pH, thế điện phân, thời gian điện phân, nồng độ clorua natri và khối lượng vật liệu tổ hợp đã được nghiên cứu. Vật liệu MnO2/GO có khả năng loại màu và nhu cầu oxy hóa học của xanh metylen với hiệu suất 99,64 và 85,85% với phương pháp EPD. Kết quả cho thấy tiềm năng của của phương pháp EPD kết hợp với vật liệu MnO2/GO để loại bỏ chất màu hữu cơ trong môi trường nước
ANTECEDENTS OF TOURISTS’ LOYALTY: THE ROLE AND INFLUENCE OF TOURISM PRODUCTS, DESTINATION IMAGE IN HOIAN WORLD CULTURAL HERITAGE SITE
The study’s aim is to examine the antecedents of destination loyalty, and considers the role and influence of tourism
products and destination image to international tourisms’ loyalty in case of HoiAn World Cultural Heritage Site. The study
suggested an integrated approach to understand tourists’ loyalty model and investigate the empirical evidence about the
relationship among tourism products, destination image, risk perception, tourist experience, destination satisfaction and tourists’
loyalty. This study also mentions important questions concerning how tourism products, destination image, tourist experience,
risk perception, and tourists’ satisfaction affect tourists’ loyalty. Smart PLS3 is used to estimate and test the relationships in the
research model. Mediation analysis and importance performance matrix analysis are also used to consider clearly the relationship
between the constructs of research model. The study’s results indicate that tourism products, destination image, tourism
experience, risk perception, and satisfaction are antecedents of international tourists’ loyalty in Hoi An World Cultural Heritage
Site. And in them, tourism products affect significantly positively to destination imagine and satisfaction, beside destination
image and satisfaction hold the role of mediator in this relationship. Implementing IPMA to identify the predecessors that have
relatively high importance for loyalty but also a relatively low performance. The results pointed out that the constructs as
satisfaction, tourism product, risk perception and image have a high importance for the tourist loyalty. The study added the
antecedent of tourism products and risk perception to the model and could enrich the literature, pointing to be possibility of a
destination loyalty model that can be applied to various contexts, especially after COVID- 19 pandemic. The study also discussed
theoretical and managerial implications for marketing tourism
PRELIMINARY STUDY OF THE ANTIOXIDANT PROPERTIES OF OPHIOCORDYCEPS SOBOLIFERA
The aim of study was to determine preliminary phytochemical analysis and the antioxidant potential of Ophiocordyceps sobolifera. The antioxidant activity of Ophiocordyceps sobolifera was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and total antioxidant activity methods. Phytochemical analyses revealed the presence of steroids, triterpenoids, alkaloids, phenolics, flavoinods, protein, carbohydarte and saponins. The antioxidant activity of the ethanol extracts and water extracts showed high antioxidant activity with the lowest half maximal inhibitory concentration (IC50) values to 0.70 from 0.95mg/mL, realtively. Total antioxidant capacity of the O. sobolifera showed contained from 5.52 ± 0.14 to 12,71 ± 0.23 mg GA/g or from 3.55 ± 0.15 to 7.87 ± .05 μmol AS/g. These data suggest that O. sobolifera is a natural source of antioxidants
In vitro antioxidant activity and bioactive compounds from Calocybe indica
Nowadays, the use of mushrooms in medicine is ubiquitous and has achieved particular success. The antioxidants in mushrooms can deactivate free radicals. This study assesses the antioxidant potential of mushroom Calocybe indica with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging methods and the total antioxidant capacity. The mushroom’s ethanol extract exhibits acceptable activity with a low IC50 value (240.11 μg/mL), approximately 2.9 times lower than that of the mushroom Ophiocordyceps sobolifera extract. The ABTS scavenging rate of the extract is around 60% at 500 µg/mL, and the total antioxidant capacity is equivalent to 64.94 ± 1.03 mg of GA/g or 77.42 ± 0.42 μmol of AS/g. The total phenolics, flavonoids, polysaccharides, and triterpenoids are equivalent to 29.33 ± 0.16 mg of GAE/g, 17.84 ± 0.11 mg of QUE/g (5.04 ± 0.04%), and 4.96 ± 0.04 mg of oleanolic acid/g, respectively. Specifically, the total triterpenoid content has been reported for the first time. The mushroom can have potential biomedical applications
Sterols isolated from the soft coral sinularia dissecta
Using various chromatographic methods, five sterols, gorgost-4-ene-3-one (1), ergost-4-ene-3-one (2), 24-methyleneergost-4-ene-3-one (3), ergost-4-ene-3,6-dione (4), and 24-methylenecholest-4-ene-3,6-dione (5), were isolated from the methanol extract of the soft coral Sinularia dissecta. Their structures were elucidated by 1D and 2D-NMR experiments and comparison of their NMR data with reported values. These compounds were isolated from S. dissecta for the first time
THÀNH PHẦN HÓA HỌC VÀ HOẠT TÍNH CHỐNG OXY HÓA CỦA CÁC DỊCH CHIẾT TỪ HOA XUYẾN CHI (Bidens pilosa)
Bidens pilosa is used in traditional medicine in Vietnam. The antioxidant potential of the ethanol extract and fractions from the flowers of Bidens pilosa was evaluated through DPPH and ABTS radical scavenging and the total antioxidant capacity method. The ethyl acetate fraction exhibits the highest activity with the lowest IC50 value (IC50 = 31.54 μg·mL–1 and IC50 = 35.33 μg·mL–1 for DPPH and ABTS radical scavenging capacity), and the total antioxidant capacity was 85.05 ± 0.28 mg GA·g–1. The composition of Bidens pilosa flowers: the total phenolic, total flavonoid, polysaccharides, and triterpenoid, was examined by using the colorimetric method, and their quantities are equivalent to 59.35 ± 0.83 mg GAE·g–1, 42.35 ± 1.50 mg QE·g–1, 4.44 ± 0.02%, and 32.88 ± 0.66 mg acid oleanolic·g–1, respectively. Specifically, the polysaccharide and total triterpenoid content of Bidens pilosa flowers was reported for the first time.Xuyến chi đã được sử dụng trong các bài thuốc cổ truyền Việt Nam. Khả năng chống oxy hóa của cao toàn phần và các cao phân đoạn từ hoa cây Xuyến chi được đánh giá thông qua ba mô hình: tổng khả năng chống oxy hoá, khả năng bắt gốc tự do DPPH và khả năng bắt gốc ABTS. Kết quả cho thấy cao ethyl acetate có khả năng chống oxy hóa tốt nhất với IC50 nhỏ nhất (IC50 = 31,54 μg·mL–1 và IC50 = 35,33 μg·mL–1 tương ứng với khả năng bắt gốc DPPH và ABTS) và hàm lượng các chất chống oxy hóa cao nhất (85,05 ± 0,28 mg·g–1 acid gallic). Hàm lượng các hợp chất có hoạt tính sinh học (tổng các hợp chất phenol, tổng flavonoid, tổng triterpenoid và polysaccharide) trong dịch chiết hoa cây Xuyến chi được xác định bằng phương pháp trắc quang. Hàm lượng tổng các hợp chất phenol và flavonoid là 59,35 ± 0,83 mg GAE·g–1 và 42,35 ± 1,50 mg QE·g–1; hàm lượng polysacharide và triterpenoid là 4,44 ± 0,02% và 32,88 ± 0,66 mg acid oleanolic·g–1. Lần đầu tiên, tổng hàm lượng triterpenoid và polysacharide trong hoa Xuyến chi được công bố
A Bibliometric Analysis of the Global Research Trend in Child Maltreatment
Child maltreatment remains a major health threat globally that requires the understanding of socioeconomic and cultural contexts to craft effective interventions. However, little is known about research agendas globally and the development of knowledge-producing networks in this field of study. This study aims to explore the bibliometric overview on child maltreatment publications to understand their growth from 1916 to 2018. Data from the Web of Science Core Collection were collected in May 2018. Only research articles and reviews written in the English language were included, with no restrictions by publication date. We analyzed publication years, number of papers, journals, authors, keywords and countries, and presented the countries collaboration and co-occurrence keywords analysis. From 1916 to 2018, 47, 090 papers (53.0% in 2010–2018) were published in 9442 journals. Child Abuse & Neglect (2576 papers; 5.5%); Children and Youth Services Review (1130 papers; 2.4%) and Pediatrics (793 papers, 1.7%) published the most papers. The most common research areas were Psychology (16, 049 papers, 34.1%), Family Studies (8225 papers, 17.5%), and Social Work (7367 papers, 15.6%). Among 192 countries with research publications, the most prolific countries were the United States (26, 367 papers), England (4676 papers), Canada (3282 papers) and Australia (2664 papers). We identified 17 authors who had more than 60 scientific items. The most cited papers (with at least 600 citations) were published in 29 journals, headed by the Journal of the American Medical Association (JAMA) (7 papers) and the Lancet (5 papers). This overview of global research in child maltreatment indicated an increasing trend in this topic, with the world’s leading centers located in the Western countries led by the United States. We called for interdisciplinary research approaches to evaluating and intervening on child maltreatment, with a focus on low-middle income countries (LMICs) settings and specific contexts
TextANIMAR: Text-based 3D Animal Fine-Grained Retrieval
3D object retrieval is an important yet challenging task, which has drawn
more and more attention in recent years. While existing approaches have made
strides in addressing this issue, they are often limited to restricted settings
such as image and sketch queries, which are often unfriendly interactions for
common users. In order to overcome these limitations, this paper presents a
novel SHREC challenge track focusing on text-based fine-grained retrieval of 3D
animal models. Unlike previous SHREC challenge tracks, the proposed task is
considerably more challenging, requiring participants to develop innovative
approaches to tackle the problem of text-based retrieval. Despite the increased
difficulty, we believe that this task has the potential to drive useful
applications in practice and facilitate more intuitive interactions with 3D
objects. Five groups participated in our competition, submitting a total of 114
runs. While the results obtained in our competition are satisfactory, we note
that the challenges presented by this task are far from being fully solved. As
such, we provide insights into potential areas for future research and
improvements. We believe that we can help push the boundaries of 3D object
retrieval and facilitate more user-friendly interactions via vision-language
technologies.Comment: arXiv admin note: text overlap with arXiv:2304.0573
Erratum: Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017
Interpretation: By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health planning
Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017
Background
The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 comparative risk assessment (CRA) is a comprehensive approach to risk factor quantification that offers a useful tool for synthesising evidence on risks and risk–outcome associations. With each annual GBD study, we update the GBD CRA to incorporate improved methods, new risks and risk–outcome pairs, and new data on risk exposure levels and risk–outcome associations.
Methods
We used the CRA framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or groups of risks from 1990 to 2017. This study included 476 risk–outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk and exposure estimates from 46 749 randomised controlled trials, cohort studies, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. We explored the relationship between development and risk exposure by modelling the relationship between the Socio-demographic Index (SDI) and risk-weighted exposure prevalence and estimated expected levels of exposure and risk-attributable burden by SDI. Finally, we explored temporal changes in risk-attributable DALYs by decomposing those changes into six main component drivers of change as follows: (1) population growth; (2) changes in population age structures; (3) changes in exposure to environmental and occupational risks; (4) changes in exposure to behavioural risks; (5) changes in exposure to metabolic risks; and (6) changes due to all other factors, approximated as the risk-deleted death and DALY rates, where the risk-deleted rate is the rate that would be observed had we reduced the exposure levels to the TMREL for all risk factors included in GBD 2017.
Findings
In 2017, 34·1 million (95% uncertainty interval [UI] 33·3–35·0) deaths and 1·21 billion (1·14–1·28) DALYs were attributable to GBD risk factors. Globally, 61·0% (59·6–62·4) of deaths and 48·3% (46·3–50·2) of DALYs were attributed to the GBD 2017 risk factors. When ranked by risk-attributable DALYs, high systolic blood pressure (SBP) was the leading risk factor, accounting for 10·4 million (9·39–11·5) deaths and 218 million (198–237) DALYs, followed by smoking (7·10 million [6·83–7·37] deaths and 182 million [173–193] DALYs), high fasting plasma glucose (6·53 million [5·23–8·23] deaths and 171 million [144–201] DALYs), high body-mass index (BMI; 4·72 million [2·99–6·70] deaths and 148 million [98·6–202] DALYs), and short gestation for birthweight (1·43 million [1·36–1·51] deaths and 139 million [131–147] DALYs). In total, risk-attributable DALYs declined by 4·9% (3·3–6·5) between 2007 and 2017. In the absence of demographic changes (ie, population growth and ageing), changes in risk exposure and risk-deleted DALYs would have led to a 23·5% decline in DALYs during that period. Conversely, in the absence of changes in risk exposure and risk-deleted DALYs, demographic changes would have led to an 18·6% increase in DALYs during that period. The ratios of observed risk exposure levels to exposure levels expected based on SDI (O/E ratios) increased globally for unsafe drinking water and household air pollution between 1990 and 2017. This result suggests that development is occurring more rapidly than are changes in the underlying risk structure in a population. Conversely, nearly universal declines in O/E ratios for smoking and alcohol use indicate that, for a given SDI, exposure to these risks is declining. In 2017, the leading Level 4 risk factor for age-standardised DALY rates was high SBP in four super-regions: central Europe, eastern Europe, and central Asia; north Africa and Middle East; south Asia; and southeast Asia, east Asia, and Oceania. The leading risk factor in the high-income super-region was smoking, in Latin America and Caribbean was high BMI, and in sub-Saharan Africa was unsafe sex. O/E ratios for unsafe sex in sub-Saharan Africa were notably high, and those for alcohol use in north Africa and the Middle East were notably low.
Interpretation
By quantifying levels and trends in exposures to risk factors and the resulting disease burden, this assessment offers insight into where past policy and programme efforts might have been successful and highlights current priorities for public health action. Decreases in behavioural, environmental, and occupational risks have largely offset the effects of population growth and ageing, in relation to trends in absolute burden. Conversely, the combination of increasing metabolic risks and population ageing will probably continue to drive the increasing trends in non-communicable diseases at the global level, which presents both a public health challenge and opportunity. We see considerable spatiotemporal heterogeneity in levels of risk exposure and risk-attributable burden. Although levels of development underlie some of this heterogeneity, O/E ratios show risks for which countries are overperforming or underperforming relative to their level of development. As such, these ratios provide a benchmarking tool to help to focus local decision making. Our findings reinforce the importance of both risk exposure monitoring and epidemiological research to assess causal connections between risks and health outcomes, and they highlight the usefulness of the GBD study in synthesising data to draw comprehensive and robust conclusions that help to inform good policy and strategic health planning
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