DIRC2 (Disrupted in renal carcinoma 2) has been initially identified as a breakpoint-spanning gene in a chromosomal translocation putatively associated with the development of renal cancer. The DIRC2 protein belongs to the MFS (major facilitator superfamily) and has been previously detected by organellar proteomics as a tentative constituent of lysosomal membranes. In the present study, lysosomal residence of overexpressed as well as endogenous DIRC2 was shown by several approaches. DIRC2 is proteolytically processed into a N-glycosylated N-terminal and a non-glycosylated C-terminal fragment respectively. Proteolytic cleavage occurs in lysosomal compartments and critically depends on the activity of cathepsin L which was found to be indispensable for this process in murine embryonic fibroblasts. The cleavage site within DIRC2 was mapped between amino acid residues 214 and 261 using internal epitope tags, and is presumably located within the tentative fifth intralysosomal loop, assuming the typical MFS topology. Lysosomal targeting of DIRC2 was demonstrated to be mediated by a N-terminal dileucine motif. By disrupting this motif, DIRC2 can be redirected to the plasma membrane. Finally, in a whole-cell electrophysiological assay based on heterologous expression of the targeting mutant at the plasma membrane of Xenopus oocytes, the application of a complex metabolic mixture evokes an outward current associated with the surface expression of full-length DIRC2. Taken together, these data strongly support the idea that DIRC2 is an electrogenic lysosomal metabolite transporter which is subjected to and presumably modulated by limited proteolytic processing.

Performance tests on caffeine’s corrosion inhibition properties and their derivatives against copper corrosion have been previously reported experimentally using gravimetric and electrochemical analyses. The test was able to measure the efficiency of their corrosion inhibition accurately. However, the caffeine and its derivatives’ structure patterns and coating mechanisms when interacting with metals during copper corrosion inhibition have not been explained in detail by experimental studies. In the present study, the theoretical density functional study (DFT), ab initio MP2, and Monte Carlo simulation approaches explain the problem. The geometrical and quantum chemical parameters of inhibitors were compared under normal and protonated conditions in the gas and aqueous environments. Theoretical studies can accurately determine the molecule’s geometrical parameters and successfully explain the quantum parameters of inhibitors. Molecular dynamics are applied to study the mechanism of interaction between inhibitors and metal surfaces in an explicit water molecule environment. The energy absorption of caffeine and its derivatives on metal surfaces was linear, with quantum parameters calculated from the density functional theory and an ab initio approach. Furthermore, these theoretical study results align with the previously reported experimental studies published by de Souza et al. The inhibition efficiency ranking of studied molecules preventing copper corrosion was caffeine > theobromine > theophylline. This theoretical approach is expected to bridge the gap in designing effective corrosion inhibitors.

Abstrak. Program pengembangan praktikum kimia berbasis kimia komputasi untuk Sekolah Menengah Atas telah dilaksanakan pada kelompok kerja guru kimia mitra (SMAN 1 Narmada dan SMAN 2 Narmada) di Kabuaten Lombok Barat, Indonesia. Kegiatan dilaksanakan dengan dengan mengadopsi langkah-langkah penelitian tindakan yang terdiri dari empat tahapan, yaitu: perencanaan, tindakan, observasi dan evaluasi, dan refleksi. Target yang telah dicapai melalui kegiatan ini adalah 1) Teridentifikasinya konsep-konsep kimia SMA yang esensial yang bisa diajarkan dengan lebih mudah bila melibatkan eksperimen berbasis kimia komputasi sebagai alternatif pengganti praktikum di laboratorium. 2) Teridentifikasinya perangkat lunak yang dapat digunakan oleh guru sebagai alternative pengganti praktikum kimia. 3) Mengukur tingkat motivasi guru sebelum dan setelah kegiatan untuk melaksanakan praktikum kimia di sekolah. 4) Adanya produk berupa buku panduan praktikum kimia SMA berbasis kimia komputasi yang dapat digunakan sebagai alternatif pengganti praktikum di laboratorium. Program ini sangat berguna untuk meningkatkan proses belajar mengajar kimia di sekolah.Kata kuci: kimia komputasi, praktikum kimia, SMA Abstract. Computer-based chemistry practicum development program for high school has been implemented at partner chemistry teacher group (SMAN 1 Narmada and SMAN 2 Narmada) in West Lombok District, Indonesia. The activities were carried out by adopting four stages of action research: planning, action, observation and evaluation, and reflection. This program has resulted in 1) the identification of essential high school chemistry concepts that can be taught more easily if they contain alternative lab-based alternatives in the laboratory. 2) the identification of software that can be used by teachers as an alternative to chemistry lab. 3) the identification of teacher motivation level before and after activities to carry out chemical lab work in school. 4) laboratory manual based on computational chemistry for high school chemistry. This program is very useful to improve the learning process of chemistry in high school.

Abstrak : Penelitian ini bertujuan untuk: 1) menghasilkan multimedia interaktif sistem koloid yang layak diterapkan di sekolah, dan menguji keefektifan multimedia interaktif tersebut dengan: 2) mengetahui apakah penguasaan konsep siswa yang menggunakan multimedia interaktif berbasis kontekstual lebih baik daripada penguasaan konsep siswa yang tidak menggunakan multimedia interaktif berbasis kontekstual pada materi pokok sistem koloid; dan 3) mengetahui apakah keterampilan berpikir kritis siswa yang menggunakan multimedia interaktif berbasis kontekstual lebih baik daripada keterampilan berpikir kritis siswa yang tidak menggunakan multimedia interaktif berbasis kontekstual pada materi pokok sistem koloid. Metode penelitian yang digunakan dalam penelitian ini adalah research and development (R&D) dengan mengikuti model pengembangan Borg &Gall. Hasil validasi ahli oleh 4 validator dan uji coba terbatas oleh 10 siswa menunjukkan bahwa multimedia interaktif sangat layak digunakan dengan skor masing-masing sebesar 4,21 dan 4,36. Uji coba lapangan menggunakan desain non-equivalent control group design dengan 2 kelas sampel, menghasilkan nilai probabilitas penguasaan konsep sebesar 0,00 (p < 0,05) dan nilai probabilitas keterampilan berpikir kritis sebesar 0,00 (p < 0,05). Dari hasil penelitian dapat disimpulkan bahwa: 1) pengembangan produk pembelajaran berupa multimedia interaktif berbasis kontekstual dapat dikembangkan dengan cara melakukan analisis materi pada setiap sub materi sebagai dasar pengembangan produk awal, selanjutnya diuji kelayakan dan efektivitasnya serta direvisi lewat validasi ahli, uji coba terbatas, dan uji coba lapangan sehingga dihasilkan produk akhir yang layak digunakan dalam proses pembelajaran di sekolah, 2) penguasaan konsep siswa yang menggunakan multimedia interaktif berbasis kontekstual lebih baik daripada penguasaan konsep siswa yang tidak menggunakan multimedia interaktif berbasis kontekstual pada materi pokok sistem koloid, dan 3) keterampilan berpikir kritis siswa yang menggunakan multimedia interaktif berbasis kontekstual lebih baik daripada keterampilan berpikir kritis siswa yang tidak menggunakan multimedia interaktif berbasis kontekstual pada materi pokok sistem koloid.Kata kunci: : multimedia interaktif, kontekstual, penguasaan konsep, keterampilan berpikir kritis Abstract : The aims of this study were to: 1) generate interactive multimedia of colloidal system which is suitable to be implemented in schools, and to test the effectiveness of an interactive multimedia by: 2) knowing whether concepts mastery of students who use context-based interactive multimedia is better than concepts mastery of students who do not use context-based interactive multimedia on subject matter of colloidal system, and 3) knowing whether critical thinking skill of students who use context-based interactive multimedia is better than critical thinking skill of students who do not use context-based interactive multimedia on subject matter of the colloidal system. The method used in this study was research ...

Artikel ini membahas tentang pemanfaatan hasil pengembangan modul kimia dengan pendekatan etnosains pada materi kimia SMA. Pemanfaatan hasil ini dilakukan di MAN 2 Lombok Tengah. Pemilihan sampel dilakukan dengan teknik purposive sampling. Pemanfaatan hasil pengembangan ini termasuk penelitian deskriptif dengan pendekatan kuantitatif, melibatkan peserta didik di MAN 2 Lombok Tengah sebanyak 110 responden. Data respon peserta didik dikumpulkan menggunakan angket dengan skala Likert dan dianalisis dengan persentase skor yang kemudian diinterpretasikan dengan kriteria kategori respon. Pemanfaatan hasil pengembangan menunjukkan bahwa respon peserta didik terhadap modul kimia dengan pendekatan etnosains termasuk dalam kriteria baik dengan skor sebesar 3.00. Artinya peserta didik memberika respon yang positif terhadap modul, sehingga pemanfaatan hasil pengembangan modul kimia berbasis etnosains yang dikembangkan dapat digunakan untuk menanamkan sikap konservasi lingkungan peserta didik di MAN 2 Lombok Tengah.

The efficiency of ethyl-p-methoxycinnamate(EPE) and its derivatives as corrosion inhibitors of iron in acid environment has been studied to find the relationship between molecular structure and electronic parameters with their efficiency of corrosion inhibition. The ab initio MP2 perturbation theory and DFT method were applied to calculate molecular structure and electronic parameters of inhibitors. Computational and experimental corrosion inhibition efficiency show that the electronic properties of molecules, including the orbital molecular frontier energy (HOMO and LUMO energy), ionization potential, electron affinity, electronegativity, number of electron transfer from inhibitor to metal and interaction energy have a strong relationship with inhibition performance. Interaction mechanism obtained from natural bond orbital analysis was employed to study the interactions between inhibitors with iron metal in more detail. The presence of electron donor groups within the frameworks of inhibitors has a less significant effect compared to π-electron contribution on corrosion inhibition performance.

This study aims to produce a valid and practical ethnoscience-based chemical module by raising salt farmers' habits. This study refers to the 4D model from Tiahgrajan, S. Semmel & Semmel, which was modified into three stages: defining, designing, and developing. Chemistry modules are tested for validity and practicality before it is used in chemistry learning. Validation was carried out by three experts and adjusted to the scoring table, while the practicality test used a student response questionnaire using a Likert scale. The result showed that the ethnoscience-based chemistry module was in the feasible and practical category used in learning to acquire scores, respectively, at a rate of 0.91 and 3.00. Penelitian ini bertujuan untuk menghasilkan modul kimia berbasis etnosains yang valid dan praktis dengan mengangkat kebiasaan petani garam. Penelitian ini mengacu pada model 4D dari Tiahgrajan, S. Semmel & Semmel yang dimodifikasi menjadi tiga tahap yaitu define, design, dan develop. Modul kimia dilakukan ujicoba kevalidan dan kepraktisan sebelum digunkaan dalam pembelajaran kimia. Validasi dilakukan oleh tiga tim ahli dan disesuaikan dengan tabel penskoran, sedangkan uji kepraktisan menggunakan angket respon peserta didik dengan menggunakan skla likert. Hasil penelitian menunjukkan bahwa modul kimia berbasis etnosains dalam kategori layak dan praktis digunakan dalam pembelajaran dengan perolehan skor berturut-turut sebesar 0.91 dan 3.00.

This study aims to obtain a valid chemistry learning device based on ethnoscience emphasizing character values and conservation behaviors. This study refers to the 4D model from Tiahgrajan, S. Semmel & Semmel which was modified into three stages, namely define, design, and develop. The chemistry learning kit that has been validated by three experts consisted of ethnics-based chemistry modules, lesson plans, student worksheets, and questionnaire sheets. The validity of chemistry learning devices was analyzed using the Aiken's V formula which was consulted to the criteria in the validity table. The results showed that the developed devices were appropriate for use in learning with an individual score of each component as follows: the implementation plan of learning got a score of 0.91 (very valid), the Chemistry module got a score of 0.91 (very valid), the student worksheet got a score of 0.89 (very valid), and the poll got a score of 0.72 (valid)