Judul: The Use of Real-Time Polymerase Chain Reaction (qPCR) in Detecting Rat Meat in The Case of Meat Adulteration
Abstrak: Kasus pemalsuan daging seperti penambahan daging tikus ke dalam daging sapi atau ayam merupakan masalah keamanan pangan yang masih ditemukan di Indonesia. Pengujian berbasis DNA (Deoxyribo Nucleic Acid) dalam kasus pemalsuan tersebut masih terbatas penggunaannya sampai saat ini. Penelitian ini bertujuan mengetahui validitas dari metode Real-Time Polymerase Chain Reaction (qPCR) dalam mengidentifikasi keberadaan DNA tikus pada produk pangan asal hewan. Metode Real-Time Polymerase Chain Reaction (qPCR) menggunakan SYBR green dievaluasi validitasnya dalam mendeteksi keberadaan daging tikus yang secara sengaja ditambahkan ke dalam daging ayam dalam berbagai konsentrasi. Parameter dalam evaluasi validitas ini meliputi specificity, repeatability, reproducibility, dan limit of detection. Hasil penelitian menunjukkan bahwa metode qPCR memiliki validitas yang baik untuk mengidentifikasi keberadaan campuran daging tikus di dalam daging ayam dalam berbagai konsentrasi. Metode ini bahkan mampu mendeteksi campuran tersebut hingga mencapai konsentrasi 0,03125%. Hal ini menunjukkan metode qPCR dapat digunakan untuk keperluan pengujian kasus pemalsuan daging terutama penambahan daging tikus ke dalam daging ayam., Beef or chicken meat adulteration is still become one of main food safety issue in Indonesia. Utilization of DNA (Deoxyribo Nucleic Acid)-based testing in solving that problem is still very limited to date. This study aimed to determine the validity of Real-Time Polymerase Chain Reaction (qPCR) method to identify the presence of rat DNA in animal food products. The validity of Real-Time Polymerase Chain Reaction method using SYBR Green Melting Curve Analysis in detecting the presence of rat meat added into chicken meat intentionally in various concentrations were evaluated. Parameters used in this validity evaluation are specificity, repeatability, reproducibility, and limit of detection. The result of this research suggested that the qPCR method had good validity to identify the presence of rat meat when it was mixed with chicken meat. This method was able to detect the compound until it reached a concentration of 0,03125%. This showed that the qPCR method can be used to examine the case of animal food product adulteration especially the addition of rat meat into chicken meat.
Keyword: Adulteration, DNA, Rat, qPCR, validity

Judul: Validation method of the Buffalo (Bubalus bubalis) DNA Identification using Real-time Polymerase Chain Reaction
Abstrak: Banyak kasus pemalsuan produk pangan berbahan dasar daging yang dijumpai di masyarakat. Penambahan daging dengan daging spesies lain yang tidak terjamin mutunya, biasanya dengan kualitas lebih rendah dapat berdampak pada ekonomi dan kesehatan. Identifikasi spesies melalui penggandaan molekul DNA target dalam satu reaksi dapat dilakukan dengan metode real-time PCR. Penelitian ini bertujuan untuk memvalidasi metode real-time Polymerase Chain Reaction (qPCR) dalam identifikasi DNA kerbau pada produk pangan asal hewan. Metode qPCR dengan SYBR green melting curve analysis digunakan sebagai pengujian validasi metode DNA kerbau dengan menggunakan kit komersial QIAGEN DNeasy Food Mericon Kit. Parameter validasi metode yang digunakan dalam penelitian ini meliputi repeatability,reproducibility, limit of detection, dan spesifisitas. Hasil penelitian pada parameter validasi repeatability yaitu sampel positif teramplifikasi 100% sedangkan untuk sampel negatif tidak teramplifikasi. Hasil uji t terhadap nilai Ct dan Tm pada parameter reproducibility DNA kerbau menunjukkan bahwa tidak terdapat perbedaan yang nyata dalam mendeteksi DNA kerbau pada dua pengujian dengan menggunakan metode qPCR, nilai limit deteksi untuk PCR spesifik kerbau sebesar 0,0625%, serta tidak terdapat reaksi silang antar DNA spesies pada pengujian spesifisitas. Metode qPCR dapat dijadikan sebagai metode pengujian untuk mengidentifikasi DNA spesies yang tidak dikehendaki pada pangan asal hewan yang beredar di masyarakat, khususnya terkait pemalsuan daging., There are many cases of fraud meat-based food products found in society. Meat substitution with an unsecured meat, usually of less quality, could have economic and health repercussions. Identification of species utilizing the multiplication of target DNA molecules in a single reaction can be carried out by real-time PCR. This research was aimed to validate the real-time polymerase chain reaction (qPCR) method for identifying buffalo DNA on animal food product. The qPCR method with SYBR green melting curve analysis was used as a validation test for the buffalo DNA. The validation parameters used in this study were repeatability, reproducibility, limit of detection, and specificity. The results showed that on repeatability validation parameters were 100% on positive and negative samples. The t test results on the Ct and Tm values of buffalo DNA reproducibility parameters showed that there was no significant difference in detecting buffalo DNA in two examination with using the qPCR method. The limit of detection (LOD) for buffalo using this method was 0,0625%, and there was no cross-reaction between DNA species in the specificity test. The qPCR method can be used as a testing method to identify the DNA of unwanted species in food of animal origin circulating in the community, especially related to meat adulteration.
Keyword: adulteration, buffalo, DNA, PCR, validation

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.
Keyword: