Judul: Interaction of Genotype and Environment on Flavonoid Content, Terpenoid Content, also Antioxidant Activity of Willow-leaved Justicia
Abstrak: Gandarusa (Justicia gendarussa Burm. f.) merupakan tanaman yang sering dimanfaatkan karena kandungan antioksidannya. Gandarusa menghasilkan variasi akumulasi metabolit sekunder jika ditanam pada lingkungan yang berbeda-beda. Penelitian bertujuan mengukur kandungan flavonoid, terpenoid, serta aktivitas antioksidan pada daun gandarusa dan mendapatkan informasi mengenai stabilitas gandarusa terhadap penanaman di tiga lokasi (Bogor, Cianjur, Sukabumi). Tahapan penelitian meliputi pengujian kadar total flavonoid, kadar total terpenoid, dan aktivitas antioksidan dengan metode Cupric Reducing Antioxidant Capacity (CUPRAC) serta 2,20-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) dan adaptasi gandarusa terhadap penanaman multilokasi. Semua parameter uji rata-rata tertinggi pada lokasi Cianjur dan genotipe G2, kecuali kadar total terpenoid pada genotipe G3. Stabilitas genotipe dan lingkungan menunjukkan genotipe G1 spesifik pada lokasi Bogor, genotipe G2 spesifik pada lokasi Cianjur, dan genotipe G3 spesifik pada lokasi Sukabumi pada kadar total flavonoid. Genotipe G1 spesifik pada lokasi Bogor, genotipe G2 spesifik pada lokasi Sukabumi, dan genotipe G3 spesifik pada lokasi Cianjur pada kadar total terpenoid. Aktivitas antioksidan metode CUPRAC menunjukkan genotipe G1 spesifik pada lokasi Cianjur dan genotipe G2 spesifik pada lokasi Sukabumi, dan genotipe G3 spesifik pada lokasi Bogor. Aktivitas antioksidan metode ABTS menunjukkan genotipe G1 spesifik pada lokasi Sukabumi, genotipe G2 spesifik pada lokasi Bogor, dan genotipe G3 spesifik pada lokasi Cianjur., Willow-leaved justicia (Justicia gendarussa Burm. f.) is often used because of its antioxidant content. Differences in environmental conditions could indirectly affect the plant’s antioxidant activity. This research aimed to measure flavonoid, terpenoid, and antioxidant activity, also information about the stability of willow-leaved justicia on cultivation in three locations (Bogor, Cianjur, Sukabumi). This research used four types of parameters which are total flavonoid content, total terpenoid content, and antioxidant activity measured by the CUPRAC assay and ABTS assay. The highest in all parameters was obtained from Cianjur and G2, except total terpenoid content in G3. Genotype and environment stability indicated G1 had good stability at Bogor, G2 had good stability at Cianjur, and G3 had good stability at Sukabumi on total flavonoid content parameter. G1 had good stability at Bogor, G2 had good stability at Sukabumi, and G3 had good stability at Cianjur on total terpenoid content. The CUPRAC assay showed that G1 had good stability at Cianjur and G2 had good stability at Sukabumi, and G3 had good stability at Bogor. The ABTS assay showed that G1 had good stability at Sukabumi, G2 had good stability at Bogor, and G3 had good stability at Cianjur.
Keyword: antioxidant, flavonoids, multilocation, terpenoids, Willow-leave justicia

Judul: Stability of Three Genotypes of Gandarusa at Three Planting Locations based on Total Phenolic Content and Antioxidant Activity
Abstrak: Gandarusa (Justicia gendarussa Burm. f.) adalah tanaman herbal yang dapat dikembangkan potensinya berdasarkan stabilitas genotipenya. Penelitian ini bertujuan menyeleksi tiga genotipe dengan penanaman multilokasi (Bogor, Cianjur, dan Sukabumi) berdasarkan parameter kadar total fenolik dan aktivitas antioksidan metode DPPH dan FRAP. Sampel diekstraksi menggunakan etanol proanalisis. Kadar total fenolik diuji menggunakan metode Follin-Ciocalteu. Aktivitas antioksidan diukur menggunakan metode DPPH dan FRAP. Data hasil pengukuran dianalisis menggunakan uji Scott-Knott dan AMMI-2. Hasil biplot AMMI-2 menunjukkan bahwa genotipe G2 (batang hitam) dapat beradaptasi secara spesifik pada lokasi Cianjur, sedangkan genotipe G1 (batang hijau) dan G3 (daun putih) tidak spesifik pada satu lokasi tertentu. Lalu, tidak ada genotipe yang stabil pada semua lokasi (Bogor, Cianjur, dan Sukabumi), sehingga diperlukan penelitian lebih lanjut untuk pengembangan genotipe gandarusa lain yang stabil di berbagai lokasi berdasarkan kandungan total fenolik dan kapasitas antioksidan (DPPH dan FRAP)., Gandarusa (Justicia gendarussa Burm. f.) is a herbal plant that can be developed based on its genotypic stability. This study aims to select three genotypes with multi-location plantings (Bogor, Cianjur, and Sukabumi) based on parameters of total phenolic content and antioxidant activity. Samples were extracted using ethanol proanalysis. Total phenolic levels were tested using the Follin-Ciocalteu method. Antioxidant activity was measured using the DPPH and FRAP methods. The results were analyzed using the Scott-Knott and AMMI-2 tests. The results of the AMMI-2 biplot showed that genotype G2 (black stem) can adapt specifically to the Cianjur location, while genotypes G1 (green stem) and G3 (white leaves) are not specific to one particular location. Then, there is no stable genotype at all locations (Bogor, Cianjur, and Sukabumi), so further research is needed to develop other willow genotypes that are stable in various locations based on total phenolic content and antioxidant capacity (DPPH and FRAP).
Keyword: antioxidant, gandarusa, multilocation test, phenolic, stability of genotype

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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