Jurnal Biofisika https://journal.ipb.ac.id/index.php/biofisika <img src="/public/site/images/admin/biofisika.jpg" alt="" width="124" height="138" align="left" />Jurnal Biofisika terbit 2 kali dalam setahun. Dikelola oleh Departemen Fisika, Institut Pertanian Bogor en-US Jurnal Biofisika APLIKASI NOZEL PADA DUA VARIETAS KENTANG UNTUK PRODUKSI BENIH SECARA AEROPONIK https://journal.ipb.ac.id/index.php/biofisika/article/view/9345 <em>Seed is a major problem for potato growers in Indonesia. Therefore, the acceleration of seed potato production is needed to reduce dependence on imports. One of the important things in the aeroponic system is a good oxygenation of each grain fog nutrient solution to the plant roots. The purpose of this study is to get a good nozzle type on nutrition aeroponic system. Seed potatoes used are varieties of Granola and Atlantic. Factors tested: type of nozzle (N) : N<sub>1</sub> (spray jet blue : 55 lt/ h, beam diameter (d): 2,4 m), N<sub>2</sub> (green jet spray : 90 lt/h, d : 3,2 m), N<sub>3</sub> (microsprays black yellow : 70 lt/h, d: 1 m). Research using a randomized block design with three replications. Analysis of the data using analysis of variance followed by Duncan's multiple range test at level 5 %. The results showed that the use of a good nozzle on aeroponics system is the specification 55 l/h nozzle, d: 2,4 m and 90 lt/h, d: 3,2 m. Microsprayer with specification of 70 llt/h, d: 1 m is less suitable because it has less spread bursts specification. Varieties of potato plants that provide both growth and yield up to 65 days after planting is Granola.</em> Eni sumarni Copyright (c) 2014-03-01 2014-03-01 10 1 SINTESIS DAN KARAKTERISTIK MEMBRAN NILON YANG BERASAL DARI LIMBAH BENANG https://journal.ipb.ac.id/index.php/biofisika/article/view/9346 <em>Recently, the technology of membrane is developed directly. Many attractive things of membrane is able to be studied, therefore many ideas emerged on the aspect of synthetic membrane fabrication from many materials, furthermore it is able to used substituting for the function of natural membrane. The purpose of this study are able to know and study the influence of the TiO<sub>2</sub> additional on the compounds of the nylon thread in market and on the characteristic of electricity and mechanics. The membrane was fabricated by a phase inversion method on weight variation. The characterizations were done which were the characteristic of electricity (impedance, capacitance, conductance and loss coefficient), the characteristic of mechanics (compression and attraction) and the analysis of on the compounds of the nylon membrane using FTIR. The most optimum characteristic of mechanics are the membrane with nylon weight of 3.5 g and 6.0 g, furthermore from the mechanics characteric was treated the TiO<sub>2</sub> dopping. the compounds of the nylon membrane was observed by using FTIR which showed that exist PO<sub>4</sub> in the natural membrane and the TiO<sub>2</sub> dopped membrane</em> Epa Rosidah Apipah Copyright (c) 2014-03-01 2014-03-01 10 1 KARAKTERISTIK FLUKS MEMBRAN DALAM PROSES FILTRASI LIMBAH CAIR INDUSTRI PELAPISAN LOGAM https://journal.ipb.ac.id/index.php/biofisika/article/view/9347 <em>Environmental pollution that caused by electroplating wastewater can be solved by membrane technology. Chitosan and silica have been used widely in the wastewater treatment process and also easily formed into membranes. The purpose of this study is to analyze characteristics of membrane flux , which is one indicator of the quality of the performance of the membrane. The membranes used in the filtration process is made of chitosan and silica rice husk ( biosilika ) with inverse phase technique. Variations in the mass ratio of chitosan and biosilika are 1, 1.5, 2, and 3 for membrane A, B, C, and D respectively. The results of flux showed that the membrane flux decreased exponentially with increasing time. Flux caharcteristics of membrane B is better than others because the average flux and porosity in the electroplating wastewater filtration is higher than the others, namely 19115.62 L/m<sup>2</sup>hours and 87.79 % respectively. The mechanism of membrane fouling on chitosan - biosilika has caused by blocking of a number of membrane pores is described by curves fitting of flux decline to the experimental data.</em> Fifia Zulfi Copyright (c) 2014-03-01 2014-03-01 10 1 OPTIMASI SERAT KENAF SEBAGAI FILLER BIOKOMPOSIT DENGAN ADITIF SERBUK DAUN TEMBAKAU PADA APLIKASI PAPAN GIPSUM PLAFON https://journal.ipb.ac.id/index.php/biofisika/article/view/9349 <em>Synthesis and characterization of biocomposite gypsum board ceiling based on kenaf fiber has been performed compression molding method with variation of woven and uniform filler. The optimum fiber concentration on the fiber are woven with 10 % kenaf fiber, 88 % matrixes gypsum, 1 % PVA (Polivinil Alcohol) and tobacco. The test resulted that the hardness and impact mechanical of the resulted product was higher than the commercial gypsum. The highest absorption of gypsum board is 25 % owned by fiber glass composite, on biocomposite with addition of tobbaco is 21 % and the lowest is 13 % on biocomposite without addition of tobbaco. The highest value on thickness development is 1.85 % owned by fiber glass composite. On biocomposite with addition of tobbaco is 1.73 % and the lowest is 0.4 % on biocomposite without addition of tobbaco. Density of biocomposite is 1.6 g cm<sup>-3</sup>, whereas density of fiber glass composite is 1.98 g cm<sup>-3</sup>. The test result showed that the kenaf’s fiber and tobbaco leaf powder is reliable to use as the filling material for the the gypsum plafon.</em> Vina Fauziah Copyright (c) 2014-03-01 2014-03-01 10 1 SIMULASI LAJU PENURUNAN GLUKOSA DARAH DIABETES TIPE 1 SETELAH MELAKUKAN AKTIVITAS FISIK https://journal.ipb.ac.id/index.php/biofisika/article/view/9351 <em>Decline rate modeling of blood glucose in type 1 diabetes after exercise that made by Roy<sup>2</sup> not attach consumption glucose factor. In the fact, type 1 diabetes mellitus (T1DM) consume the glucose before exercise. Consumption of glucose can from food or drinks. In the research, we modify Roy’s<sup>2</sup> model by attached glucose consumption. Result of modification model isn’t too different to experiment data. This is evident from R2 value obtained for 99.30%. In addition, this modification result isn’t much different with Anirban Roy’s model that have R2 value is 99.25%. Parameter values used for this model modification it’s identic, they are insulin injection (u1) is 15 µU min-1, exercise duration is 60 minute, patient boddy mass is 80 kg, and glucose consumption (D) is around to 10 mg min-1 dl-1 (for parameter values in modification model). Hypoglycemia will occur if amount of insulin injected into patient too much, while hyperglycemia can occur if amount of insulin injected into patient too little.</em> Muhammad Khalid Copyright (c) 2014-03-01 2014-03-01 10 1 SIMULASI DOCKING KURKUMIN ENOL, BISDEMETOKSIKURKUMIN DAN ANALOGNYA SEBAGAI INHIBITOR ENZIM12-LIPOKSIGENASE https://journal.ipb.ac.id/index.php/biofisika/article/view/9354 <em>Docking simulations of curcumin and its analogs have been conducted on 12-Lipoxygenase receptor enzyme. Semi-flexibledocking simulation has been performed using AutoDock Vina.This research is aimed to find the most stable compounds of curcumin that bind with 12-Lipoxygenase enzyme. Ligands used in this research consist of enol curcumin, bisdemetoxycurcumin, and two analogs (analog A and B). Gibbs free energy and the type of chemical bonding and binding sites of ligand-receptor docking aresome of the results discussed in this paper. All.simulation results of curcumin and its analogs have shown lower binding affinitycompared to arachidonate acid (natural ligand of 12-Lipoxygenase) and ibuprofen which act as competitive inhibitors.Enol curcumin has been found tohave the best score of Gibbs free energy ∆G = -8.4 kcal/mol. Overall curcumin and its analogs have shown potential as stable Inhibitors for 12-Lipoxygenase and able to block the production of Leukotrien and 12-HETE which responsible for inflammation.</em> Gita Syahputra Copyright (c) 2014-03-01 2014-03-01 10 1 ANALISA PASANGAN JEMBATAN GARAM RESIDU GLU15-LYS4 PADA KESTABILAN TERMAL PROTEIN 1GB1 https://journal.ipb.ac.id/index.php/biofisika/article/view/9355 <em>Simulation on protein G domain B1 (1GB1) have been performed using NAMD2. This protein is well-known for its high termal stability (melting point about 363 K) and attract many scientists to study it. The aim of this research is to study the effect of mutation on salt-bridge pairs GLU15-LYS4 to the thermal stability of 1GB1 protein. The pair was chosen based on simulation analysis for native structure (wild-type) in which non-binding energy towards zero when unfolding occurred (t=678 ps). Mutations were done by interchanging the position of the pair, neutralizing one of the residue, and neutralizing both residues in the pair. This research is focused on observing the changes caused by the mutations without paying attention to the change of protein function. The results show that neutralizing GLU15 to ASN 15 would increase the thermal stability which indicated by longer unfolding time at 820 ps.</em> kania N Sawitri Copyright (c) 2014-03-01 2014-03-01 10 1