• 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.

• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.393-403
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• 2024

As an archipelagic country, Indonesia is surrounded by large and small islands. Many mangrove plant species are found along the coasts surrounding large and small islands. Besides their conservation value, mangrove plants provide various benefits, including the use of their leaves, fruit, bark, and wood as raw materials in pharmaceutical and other industries. Additionally, mangrove wood is a potential raw material for pulp and paper production. It is essential to study the fiber dimensions of the wood to identify the appropriate characteristics of raw material for pulp and paper. Therefore, in this study, we comprehensively analyzed the differences in the wood fiber dimensions of seven mangrove species from the Indramayu Regency, West Java Province, namely Avicennia alba, Bruguiera gymnorhiza, Bruguiera cylindrica, Hibiscus tiliaceus, Sonneratia ovata, Sonneratia caseolaris, and Excoecaria agallocha. For this analysis, maceration followed the Forest Product Laboratory guidelines, and preparation followed the Sass method. The fiber length, diameter, and lumen diameter were measured using a light microscope. Based on the values of the length and dimension derivatives, the fibers of these mangrove wood species were grouped into quality classes II or III for use as raw materials for the pulp and paper industry. The wood fibers of H. tiliaceus, A. alba, S. caseolaris, and E. agallocha met the quality class criterion II, whereas wood species fibers of B. gymnorhiza, B. cylindrica, and S. ovata met the quality class criterion III.

• 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.

• 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 the Korean Wood Science and Technology
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• v.52 no.4
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• pp.343-362
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• 2024

Eurycoma longifolia (pasak bumi) is a popular medicinal plant in Indonesia and is widely used in various products. Its high economic value has caused illegal harvesting and product falsification. Using molecular techniques, the authentication and traceability of E. longifolia derivatives can be controlled to ensure consumer safety. Therefore, this study aimed to authenticate the products and derivatives of E. longifolia (pasak bumi) produced, marketed, and consumed in Indonesia using molecular identification techniques. Genomic DNA from 37 leaf samples collected from the Sumatran mainland and the Riau Islands and six E. longifolia products were amplified and sequenced using trnL-trnF and internal transcribed spacer (ITS) regions. The results revealed that all leaf samples were indeed E. longifolia based on the markers used, with the six products, only the herbal tea product (sample code TCPB) was most likely derived from E. longifolia based on the two regions, suggesting that not all products labelled as E. longifolia in the market are authentic. The results also indicated that several other plants species are used as substitutes or adulterants, including Simaba spp., Simarouba spp., Homalolepis spp., Vernonia gigantea, Elephantopus scaber, Gymnanthemum amygdalinum, Cyanthillium spp., Potentilla lineata, Ailanthus altissima, Geijera paniculata, Hannoa chlorantha, and Dalbergia spp. Klebsiella pneumoniae bacteria were also identified in this study on the outer wooden cup of E. longifolia products. Therefore, this molecular approach is effective in identifying the authenticity of E. longifolia products, with trnL-trnF and ITS as the recommended DNA markers.

• 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.