• Journal of Electrochemical Science and Technology
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• v.10 no.4
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• pp.416-423
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• 2019

A novel non-enzymatic oxalic acid (OA) sensor based on the platinum/carbon black-nickel-reduced graphene oxide (Pt/CBNi-rGO) nanocomposite is reported. The nanocomposites were prepared by the ethylene glycol reduction method. Their morphology and chemical composition were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The results clearly demonstrated the formation of the Pt/CB-Ni-rGO nanocomposite. The electrocatalytic activity of the Pt/CB-Ni-rGO electrode was investigated by cyclic voltammetry. It was determined that the appropriate amount of Pt enhanced the catalytic activity of Pt for oxalic acid electro-oxidation. Moreover, the modified electrode was determined to be highly selective for oxalic acid without interference from compounds commonly found in urine including uric acid and ascorbic acid. The chronoamperometric signal gave a wide linearity range of 20 μM-60 mM and the detection limit (3σ) was found to be 2.35 μM. The proposed method showed high selectivity, stability, and good reproducibility and could be used with micro-volumes of sample for the detection of oxalic acid. Finally, the oxalic acid content in artificial and control urine samples were successfully determined by our proposed electrode.

• Journal of the Korean Wood Science and Technology
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• v.48 no.3
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• pp.303-314
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• 2020

Gambir is a non-wood forest product with a potential of being used as wood adhesive, due to about 33% catechin in it. Meanwhile, catechins and sucrose have not been studied as adhesives. Therefore, basic characteristics of gambir-sucrose adhesives were investigated. In this research, adhesives were prepared by dissolving gambir and sucrose in distilled water, at different blending ratios of the gambir/sucrose such as 100/0, 75/25, 50/50, and 25/75 wt%. Furthermore, gas chromatography-mass spectrometry (GC-MS) was employed to determine the gambir chemical compositions, and Fourier transform-infrared (FTIR) spectroscopy was carried out to identify chemical bonds. Particleboards with a target density of 0.8 g/㎤ were then manufactured by hot-pressing for 10 min at 200℃. The internal bond (IB) strength of particleboard was subsequently measured. Based on the GC-MS analysis, 31.11% of catechin was identified. In addition, the viscosity, density, solid content, and gelation time of the adhesives, and insoluble matter content (IMC) in boiling water were 7.30~33.24 mPa.s, 1.2~1.3 g/㎤, 25.56~28.44%, 73~420 min, and 29.75~62.10%, respectively. Adding sucrose to the adhesive was observed to raise the IMC from 49.05 to 62.10%, at 180℃ and 200℃. FT-IR analysis showed that the gambir absorption peaks occurred at approximately 1620 cm^-1, assigned to the C=O stretching of 5-hydroxymethylfurfural, which tended to increase with the addition of sucrose. The reaction between gambir and sucrose was observed in the form of the dimethylene ether bridge. The 25/75 wt% gambir-sucrose adhesives and 200℃ hot-pressed temperature resulted in the highest IB strength (0.89 MPa), and met the requirement of JIS A5908-2003 type 18. Consequently, the gambir-sucrose adhesive could be used as a particleboard adhesive.

• Natural Product Sciences
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• v.27 no.1
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• pp.45-48
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• 2021

One new compound, macasiamenene V (1), and two known stilbenes (2-3) were isolated from Macaranga inermis Pax & K.Hoffm leaves. The structure of 1 was fully assigned based on the information on high-resolution MS and (1D, 2D) NMR spectra. The cytotoxic of compounds 1-3 was evaluated against 4T1 and HeLa cells. Compounds 2-3 showed high activity against HeLa cells with an IC50 value of 1.09 and 0.88 ㎍/mL, respectively.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.17-30
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• 2023

The current research aims to reveal the impact of using some participatory e-learning strategies (participatory product - classroom web simulation) in developing cognitive achievement, electronic course design skills, and - skills list - Torrance test of innovative thinking). The tools of innovative thinking among a sample of Information Science students. To achieve the objectives of current research, the researcher designed an educational website to train students to produce electronic courses via the web, according to the two participatory e-learning strategies. The researcher used a set of tools represented in (achievement test research and experimental treatment were applied to a sample of the Faculty of Computer students at Umm Al-Qura University. The results found that both participatory product strategy and web simulation have an imact on developing learning aspects discussed in the research. As for which of the two strategies had a greater impact than the other, it turned out that the web simulation strategy had a greater impact than the participatory product strategy in developing these aspects.

• Natural Product Sciences
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• v.27 no.3
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• pp.172-175
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• 2021

Sesbagrandiflorain F (1), a novel 2-arylbenzofuran, and two more 2-arylbenzofurans (2-3), were isolated from the stem bark of Sesbania grandiflora L. Based on information HRESIMS data, 1D, and 2D NMR spectra, the structure of 1 was fully assigned. Compounds 1-3 were tested for cytotoxicity in MCF-7 and HeLa cells. Compounds 1 and 3 showed moderate activity against MCF-7 cells with an IC₅₀ value of 2.68 and 4.08 ㎍/mL, respectively. Conversely, all of the isolates were inactive towards HeLa cells.

• Natural Product Sciences
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• v.25 no.3
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• pp.244-247
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• 2019

A new isoprenylated stilbene, flavestinK (1) together with two known isoprenylated stilbenes, flavestin B (2), flavestin G (3), and two isoprenilated flavanones, 4-O-methyl-8-isoprenylnaringenin (4) and 8-isoprenyl-5,7-dihydroxyflavanone (5) were isolated from the leaves of Macaranga recurvata Gage. All of the structures have been determined based on HRESIMS, 1D and 2D NMR spectral data. All of the isolated compounds were evaluated for their cytotoxicity against three human cancer cells (HeLa, T47D and WiDr). Compound 1 showed higher activity than doxorubicin against HeLa cells with $IC_{50}$ value of $13.1{\mu}g/mL$.

• Journal of applied mathematics & informatics
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• v.36 no.5_6
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• pp.397-409
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• 2018

The aim of this research note is to evaluate two generalized integrals involving the product of generalized Bessel function and Jacobi polynomial by employing the result of Obhettinger [2]. Also, by mean of the main results, we have established an interesting relation in between $Kamp{\acute{e}}$ de $F{\acute{e}}riet$ and Srivastava and Daoust functions. Some interesting special cases of our main results are also indicated.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.1
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• pp.333-343
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• 2022

Humans are facing many environmental challenges. Climate change, water pollution, global warming, and hazardous waste disposal are all issues that many countries throughout the world are dealing with. People's psychology and consumer behavior are significantly affected by these challenges, particularly generation Z, which is immediately affected by environmental changes. Young people have a strong sense of curiosity and have access to readily updated knowledge. Today's youth, in particular, live a civilized and responsible lifestyle. As a result, people recognize the significance of their own consumption behavior in affecting environmental change and are increasingly replacing them with green, ecologically friendly products as a fantastic method to mitigate their harmful consequences. In this research, there are four factors related to the young generation and environmental awareness that affect green consumption intention: perceived environmental responsibility, green knowledge, green attitude, and green product value. The goal of this study is to look into how detrimental environmental changes affect Generation Z's green consumption habits. This study used primary data from over 1000 people in the age group, which was processed using the AMOS 20 software. All the characteristics described above had an impact on Generation Z's green consumption intentions, according to the findings.

• Communications for Statistical Applications and Methods
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• v.30 no.2
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• pp.191-213
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• 2023

Unit distributions are frequently used in probability theory and statistics to depict meaningful variables having values between zero and one. Using convenient transformation, the unit inverse exponentiated weibull (UIEW) distribution, which is equally useful for modelling data on the unit interval, is proposed in this study. Quantile function, moments, incomplete moments, uncertainty measures, stochastic ordering, and stress-strength reliability are among the statistical properties provided for this distribution. To estimate the parameters associated to the recommended distribution, well-known estimation techniques including maximum likelihood, maximum product of spacings, least squares, weighted least squares, Cramer von Mises, Anderson-Darling, and Bayesian are utilised. Using simulated data, we compare how well the various estimators perform. According to the simulated outputs, the maximum product of spacing estimates has lower values of accuracy measures than alternative estimates in majority of situations. For two real datasets, the proposed model outperforms the beta, Kumaraswamy, unit Gompartz, unit Lomax and complementary unit weibull distributions based on various comparative indicators.

• Journal of Distribution Science
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• v.19 no.9
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• pp.101-111
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• 2021

Purpose: This study discusses and discovers the important role of fashion product coolness in affecting consumers' perceived value and consumers' value creation behavior. Accordingly, fashion product coolness exerts a direct effect on perceived value while perceived value has a direct impact on value creation. Besides, fashion product coolness has an indirect effect on value creation through perceived value. Research design, data, and methodology: This study adopts the quantitative research approach by cross-sectional technical on a sample of 319 respondents in Vietnam. PLS-SEM has been used to analyze the survey data. Results: The result indicates that the proposed direct and indirect effects are significant. Specifically, utilitarian "coolness" and hedonic "coolness" have positive impacts on perceived value. The perceived value poses an impact on consumers' value creation behavior, including customer lifetime value and influencer value. Finally, the perceived value links utilitarian "coolness", hedonic "coolness" with customer lifetime value and influencer value. Conclusions: Fashion distribution is playing an increasingly important role in the retail sector of the economy. Fashion distribution activities are greatly influenced by the perceived value of consumers. The findings are supposed to strengthen the beliefs of fashion brands and retailers in the promotion of value creation and consumers' perceived value in the field of fashion distribution.