Judul: Identifikasi Metabolit Akar Sidaguri (Sida rhombhifolia L.) Berdasarkan Waktu Tanam Berbeda Menggunakan LC-MS/MS
Abstrak: Sidaguri (Sida rhombifolia L.) merupakan salah satu jenis tanaman yang telah digunakan sebagai obat tradisional dengan berbagai khasiat untuk mengobati banyak penyakit karena adanya kandungan metabolit bioaktif di dalamnya. Kandungan metabolit di dalam akar tanaman sidaguri dipengaruhi oleh beberapa faktor, salah satunya adalah usia tanam. Penelitian ini bertujuan mengidentifikasi senyawa dan mengelompokkan ekstrak akar sidaguri berdasarkan waktu tanam berbeda menggunakan data hasil ekstraksi yang diperoleh dari LC-MS/MS yang dikombinasikan dengan kemometrik. Sebanyak 19 senyawa teridentifikasi dan terkonfirmasi pada ekstrak akar tanaman sidaguri dengan usia tanam 3, 4, dan 5 bulan. Senyawa-senyawa tersebut termasuk ke dalam golongan fenolik, alkaloid, steroid, flavonoid, kumarin, asam benzoat dan asam lemak. Berdasarkan hasil pengelompokkan dengan PCA menggunakan variabel luas puncak 19 senyawa metabolit yang teridentifikasi, ekstrak sidaguri mengelompok sesuai usia tanam masing-masing dengan total plot skor sebesar 68%., Sidaguri (Sida rhombifolia L.) is a type of plant that has been used as a traditional medicine with various properties for treating many diseases because of the bioactive metabolites it contains. The metabolites content in the roots of the sidaguri were affected by some factors, such as cultivation age. This research aims to identify compounds and classify sidaguri root extracts based on different planting times using extraction data obtained from LC-MS/MS combined with chemometrics.. A total of 19 compounds were identified and confirmed in the root extract of the sidaguri plant with a planting age of 3, 4 and 5 months. These compounds belong to the phenolic, alkaloids, steroids, flavonoids, coumarins, benzoic acid and fatty acids groups. Based on the results of grouping using PCA using the peak area variable of 19 identified metabolite compounds, sidaguri extracts were grouped according to their respective planting ages with a total score plot of 68%.
Keyword: metabolit, metabolit sekunder

Judul: Classification of Sidaguri’s Stem (Sida rhombifolia) Based on Different Cultivation Ages using LC-MS/MS Combined with Chemometrics
Abstrak: Sidaguri (Sida rhombifolia) merupakan jenis tanaman yang telah banyak dimanfaatkan sebagai obat tradisional karena kandungan metabolit bioaktif di dalamnya. Kandungan metabolit di dalam batang tanaman tersebut dipengaruhi oleh beberapa faktor, salah satunya adalah usia tanam. Penelitian ini bertujuan mengidentifikasi kandungan metabolit ekstrak batang spesies tersebut dengan usia tanam berbeda menggunakan LC-MS/MS dan dikelompokkan menggunakan principal component analysis (PCA). Sampel diekstraksi menggunakan metanol (LC-MS grade) dengan sonikasi. Sebanyak 21 senyawa teridentifikasi secara putatif pada ekstrak batang sidaguri dengan usia tanam 3, 4, dan 5 bulan. Senyawasenyawa tersebut termasuk ke dalam golongan asam fenolat, fenolik aldehida, alkaloid, steroid, flavonoid, kumarin, asam amino dan asam lemak. Berdasarkan hasil pengelompokan dengan PCA menggunakan variabel luas pita 21 metabolit yang teridentifikasi, ekstrak sidaguri mengelompok sesuai dengan usia tanam masing-masing dengan total plot skor sebesar 78%., Sidaguri (Sida rhombifolia) is a plant widely used as a traditional medicine because of its bioactive metabolite content. The metabolites in sidaguri were affected by some factors, such as cultivation age. This study aimed to identify metabolites based on diferrent cultivation ages and classify them using principal component analysis (PCA). Samples from 3, 4, and 5 months post planting were extracted using methanol (LC-MS grade) using sonication. Twenty-one metabolites were putatively identified from all extracts. These metabolites belong to phenolic acids, phenolic aldehydes, alkaloids, steroids, flavonoids, coumarins, amino acids and fatty acids. Based on clustering result by PCA using 21 identified metabolites peak area, each extract was grouped according to cultivation ages with a total score plot of 70%.
Keyword: Sida rhombifolia, LC-MS/MS, metabolite profiling, PCA

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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