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All Journal Jurnal Penelitian Pendidikan IPA (JPPIPA) Acta Chimica Asiana
Agus Abhi Purwoko
University of Mataram
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Education Materials Science & Nanotechnology Physics

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Theoretical study on the binding selectivity of 18-membered azacrown ethers with alkaline earth metal species Saprini Hamdiani; Lalu Rudyat Telly Savalas; Agus Abhi Purwoko; Saprizal Hadisaputra
Acta Chimica Asiana Vol. 1 No. 1 (2018)
Publisher : Chemistry Education Program, the University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (859.878 KB) | DOI: 10.29303/aca.v1i1.5

Abstract

The binding selectivity of 18-membered azacrown ethers (monoaza- N1, diaza- N2, triaza- N3, tetraaza- N4, pentaaza- N5, and hexaaza-18-crown-6 N6) with Ca2+, Sr2+, Ba2+ have been studied by density functional theory (DFT) calculations. The complex binding selectivity was analyzed in term of interaction energies, thermodynamic properties, second order interaction energies, and charge transfer effects. The geometrical study shows that Ca2+ and azacrown complexes acquire envelope like structure, leading to shorter bond lengths. As a result, these complex systems have the highest interaction energies. Theoretical study also showed that N6 complex with alkaline earth metal ion were shown to be more stable complex than those ligand with lower nitrogen number. The interaction energy order is N0 < N1 < N2 < N3 < N4 < N5 < N6. This trend shows that the presence of more nitrogen on the crown ether cavity increases the interaction energies by approx. 7.3 % in going from N0 to N6. It is clearly showed that the contribution of the number of nitrogen play a dominant role in the binding selectivity of these systems.
Isolation of Lipase from Candlenut Seeds and Its Immobilization in Polyacrylamide Gel Zella Yaumin Nasry; Nyoman Maya Krisnawati; Erin Ryantin Gunawan; Jannatin ‘Ardhuha; Agus Abhi Purwoko; Lalu Rudyat Telly Savalas
Jurnal Penelitian Pendidikan IPA Vol. 8 No. 3 (2022): July
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v8i3.1483

Abstract

In general, lipase enzymes are used in the form of free lipase enzymes which can only be used once and are less effective, so that their use is costly. Therefore, to maximize the use of the lipase enzyme, immobilization of the enzyme that allows multiple use is a choice. The purpose of this study was to determine the activity of the candlenut (Aleurites moluccana (L.) Wild) lipase in its free form and in immobilization form. The stability of the immobilized lipase enzyme with repeated use was also investigated. The enzyme was immobilized by trapping method using polyacrylamide gel. The immobilized lipase enzyme was characterized to determine its stability after repeated use with various gel concentrations. The crude extract of the lipase of candlenut seed sprouts had an activity of 2.32 U/mL, whereas the activity of the immobilized lipase enzyme in polyacrylamide gel at concentrations of 6%, 8%, and 10%, were 2.133; 2,259; and 2,311 U/mL, respectively. The optimum temperature for the immobilized lipase enzyme was 30 oC and the optimum pH was 7.5. After five time us usage, the immobilized enzyme showed activities of 49.49%, 72.60% and 86.53%, for 6%, 8% and 10% polyacrylamide gel, respectively. These results indicate that the immobilized lipase enzyme from seed sprouts of candlenut (Aleurites moluccana (L.) Wild) by trapping method using 10% polyacrylamide gel can maintain its stability after five times of use
Trends in Ecotourism Research in Indonesia: Basic Analysis of the Development of Ecotourism-Based Teaching Materials Hamidi Hamidi; Agus Abhi Purwoko; Agil Al Idrus; Ahmad Harjono; Joni Rokhmat; A.A. Sukarso
Jurnal Penelitian Pendidikan IPA Vol 9 No 7 (2023): July
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v9i7.4028

Abstract

Currently and in the future, tourism is expected to make the biggest contribution to increasing the country's foreign exchange in the government's efforts to realize people's welfare and prosperity. One form of tourism product as a derivative of the concept of sustainable tourism development is the concept of ecotourism development. This study aims to map the research that has been carried out related to ecotourism in Indonesia. Data were obtained from scientific papers published on Google Scholar from 2010-2022 and there were 985 published scientific papers consisting of 968 from journals, 16 from proceedings, and 11 from books. Bibliometric analysis was carried out using the Vos Viewer application. The results of the study show that Indonesia has many tourist areas that can be developed into ecotourism areas, and these can be used as objects of research on ecotourism, but during the last 10 years research has only been conducted in a few areas. In addition, research on the same thing is often carried out in different research locations. This is the weakness of research on ecotourism in Indonesia. Thus, it is concluded that there are still many areas and keywords that are different and related to the concept of ecotourism which can be used as research subjects in Indonesia. research on the same thing is often done with different research locations. This is the weakness of research on ecotourism in Indonesia. Thus, it is concluded that there are still many areas and keywords that are different and related to the concept of ecotourism which can be used as research subjects in Indonesia. research on the same thing is often done with different research locations. This is the weakness of research on ecotourism in Indonesia. Thus, it is concluded that there are still many areas and keywords that are different and related to the concept of ecotourism which can be used as research subjects in Indonesia
Co-Authors A.A. Sukarso Agil Al Idrus Ahmad Harjono Erin Ryantin Gunawan Hamidi Hamidi Jannatin ‘Ardhuha Joni Rokhmat Lalu Rudyat Telly Savalas Nyoman Maya Krisnawati Saprini Hamdiani Saprizal Hadisaputra Zella Yaumin Nasry