Judul: Simulation of One Enzyme-Based Biosensor Model with the Addition of pH Factor
Abstrak: Model matematika pada biosensor berbasis satu enzim dengan penambahan pH didasarkan pada sistem persamaan difusi dan reaksi bergantung waktu yang menggambarkan mekanisme laju reaksi substrat dan produk yang sesuai dengan reaksi katalis Michaelis-Menten. Model tersebut dideskripsikan melalui bentuk persamaan diferensial parsial, lalu persamaan tersebut diubah dalam bentuk tak berdimensi dengan cara mereduksi parameter-parameter dari persamaan. Persamaan tersebut diselesaikan menggunakan metode beda hingga secara eksplisit dan perangkat lunak MATLAB. Hasil simulasi divalidasi melalui proses kekekalan massa pada reaksi substrat dan produk. Solusi numerik dari penelitian ini dapat menggambarkan konsentrasi substrat dan produk serta respons arus listrik di dalam lapisan enzimatik ketika ditambahkan pH. Perubahan nilai parameter-parameter dalam model dapat menyebabkan perubahan dalam proses laju difusi dan reaksi. Penambahan pH dalam simulasi ini mempercepat laju reaksi substrat-produk serta melihat lebih teliti puncak arus listrik yang dihasilkan pada saat biosensor bekerja. Model biosensor berbasis satu enzim dengan penambahan pH ini diharapkan dapat dikembangkan lebih lanjut dengan fokus pada jenis enzim dan analit yang spesifik. Nilai parameter-parameter yang digunakan dalam penelitian ini dapat disempurnakan melalui studi literatur ataupun eksperimen untuk lebih mengoptimalkan model ini., The mathematical model of a single enzyme-based biosensor with pH addition is based on a system of time-dependent diffusion and reaction equations that describe the mechanism of substrate and product reaction rates corresponding to the Michaelis-Menten catalyst reaction. The model is described through the form of partial differential equations, then the equations are converted into dimensionless form by reducing the parameters of the equations. The equation is solved using the explicit finite difference method and MATLAB software. The simulation results are validated through the mass conservation process in the substrate and product reactions. The numerical solution of this study can describe the substrate and product concentrations as well as the electric current response in the enzymatic layer when pH is added. Changes in the values of the parameters in the model can cause changes in the diffusion and reaction rate processes. The addition of pH in this simulation accelerates the substrate-product reaction rate and looks more closely at the peak of the generated electric current when the biosensor is working. This single enzyme-based biosensor model with pH addition is expected to be further developed with a focus on specific types of enzymes and analytes. The values of the parameters used in this research can be refined through literature studies or experiments to further optimize this model.
Keyword: biosensor, enzim, metode beda hingga, pH, biosensor, enzyme, finite difference method, pH

Judul: Simulasi Model Biosensor Berbasis Multi Enzim dengan Penambahan Faktor pH
Abstrak: Penelitian ini membahas mekanisme difusi reagen pada biosensor berbasis multi enzim. Model yang digunakan dibentuk dari persamaan difusi dengan faktor nonlinier Michaelis-Menten akibat reaksi kimia yang terjadi pada membran katalitik. Persamaan difusi tersebut direkonstruksi sehingga hanya mengandung besaran tak berdimensi dan diselesaikan menggunakan metode beda hingga eksplisit. Pada penelitian ini, faktor pH lingkungan dipertimbangkan dan dimasukan kedalam model biosensor berbasis multi enzim. Solusi numerik berupa mekanisme difusi dan keluaran fluks listrik diperoleh pada variasi pH lingkungan tertentu. Secara keseluruhan solusi numerik model tersebut menunjukkan bahwa pada pH yang tinggi laju difusi berlangsung lebih cepat dan keluaran fluks listrik lebih besar. Selain itu, pH lingkungan dapat mempengaruhi besar signifikansi dari kondisi parameter kimia yang berbeda seperti konstanta laju reaksi dan konstanta disosiasi asam-basa., This research discusses the mechanism of reagent diffusion in multi-enzyme-based biosensors. The model used is formed from the diffusion equation with the Michaelis-Menten nonlinear factor due to chemical reactions that occur in the catalytic membrane. The diffusion equation is reconstructed so that it only contains dimensionless quantities and being solved using the explicit finite difference method. In this study, environmental pH factors were considered and included in the multi-enzyme-based biosensor model. Numerical solutions in the form of diffusion mechanisms and electric flux outputs are obtained at some environmental pH variations. Overall, the numerical solution of the model shows that at high pH the diffusion rate is faster and the electric flux output is greater. In addition, the environmental pH can significantly affect the conditions of different chemical parameters such as the reaction rate constant and the acid-base dissociation constant.
Keyword: biosensor multi enzim, metode beda hingga, biosensor berbasis pH, kinetika enzimatik, multi-enzyme biosensor, finite difference method, pH based biosensor, enzyme kinetics

Judul: Ragam jenis ektoparasit burung tekukur (Streptopelia chinensis) dan burung puter (Streptopelia bitorquata) di penangkaran
Abstrak: Spotted dove and Javan turtle dove are the bird species that are easily raised in captivity. Nevertheless, good management is required to successfully breed and raise the birds in captivity; otherwise, the condition may endanger the sustainability of the two bird species. Information on ectoparasites on the bodies of this bird as well as their captivity breeding has not been available, although admittedly taking ectoparasites from these bird families has much been done so that a research is obviously needed. This study aimed to find out various kinds of Spotted dove and Javan turtle dove ectoparasites and to learn various kinds of parasitic insects around the Spotted dove and Javan turtle dove cages. The study was conducted from April to June 2010. The methods of data collection included the general condition of the location, collection of ectoparasites specimens, processing and specimens identification. The data analysis was done descriptively and tabulated with the degree of infestation. The kinds of ectoparasites from the class of insects found in the body of Spotted dove were Goniocotes sp. and Columbicola columbae of phthiraptera order and Pseudolynchia canariensis of diptera order, and arachnida class, that is, tungau from the pterolichidae family. In terms of ectoparasites, Spotted dove and Javan turtle dove were similar, except that Javan turtle dove had no Pseudolynchia canariensis. Goniocotes sp. and Columbicola columbae were mallopaga order (biting lice) and were obligate. The kinds of parasitic insects in the vicinity of Spotted dove and Javan turtle dove cages were from the Ordo Diptera. The diptera classified as parasites included Anopheles, Culex, Psychodidae, Culicoides and Simulium, most of them vectors of disease. The presence of ectoparasites was closely related to how a breeding place is managed.
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