Journal of Mathematical and Fundamental Sciences
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Antihyperglycemic Activity of Piper crocatum Leaves and Cinnamomum burmannii Bark Mixture Extract in Streptozotocin-induced Diabetic Rats
Get PDFIndonesia presently has the fourth largest diabetic mellitus prevalence of all countries in the world. In a previous study, a mixture extract of Piper crocatum leaves and Cinnamomum burmannii bark showed in vitro antihyperglycemic activity. It acted as inhibitor of the a-glucosidase enzyme and had no toxic effect when it was administered orally to male and female rats for 28 days. In the present study, mixture extracts of P. crocatum leaves and C. burmannii bark were used to observe antihyperglycemic activity in diabetic rats induced with streptozotocin. Mixture extracts of P. crocatum leaves and C. burmannii bark were orally given to diabetic Sprague Dawley rats at various doses for 16 days. The results showed that the treatment led to a reduction of the blood glucose level, an increase in blood insulin level up to 170.75% at 1260 mg/kg body weight, maintaining the blood lipid level of the diabetic rats at a normal level, and an increase of pancreatic ß cells in the islets of Langerhans up to 2.2-fold at 1260 mg/kg body weight. The mixture extracts of P. crocatum and C. burmannii have antihyperglycemic activity, which enhances the number of pancreatic β cells
Approximate Solutions of Linearized Delay Differential Equations Arising from a Microbial Fermentation Process Using the Matrix Lambert Function
Get PDFIn this paper we present approximate solutions of linearized delay differential equations using the matrix Lambert function. The equations arise from a microbial fermentation process in a metabolic system. The delay term appears due to the existence of a rate-limiting step in the fermentation pathway. We find that approximate solutions can be written as a linear combination of the Lambert function solutions in all branches. Simulations are presented for three cases of the ratio of the rate of glucose supply to the maximum reaction rate of the enzyme that experienced delay. The simulations are worked out by taking the principal branch of the matrix Lambert function as the most dominant mode. Our present numerical results show that the zeroth mode approach is quite reliable compared to the results given by classical numerical simulations using the Runge-Kutta method
Reconstruction of Sea Surface Temperature Data based on the Sr/Ca of Porites Coral in Ambon Bay
Get PDFSea Surface Temperature (SST) data can be used to understand oceanography dynamics in Ambon Bay. However, a lack of continual and long time series in-situ SST data limited this study. To overcome this problem, the Sr/Ca composition in Porites coral taken from Outer Ambon Bay was used to reconstruct SST. The coral sample was sub-sampled monthly and analyzed using ICP-OES. Subsequently, the anchor point method was used to develop the chronology of the coral Sr/Ca based on ERSST v3b data. The regression equation results were Sr/Ca = -0.059 x SST + 10.32 (r = -0.699, n = 95, p < 0.05). The reconstructed SST based on these results was verified by in-situ data from May to November 2008. The difference was found to be 1.2-2.5 °C (σ = 0.05%). This results lead us to conclude that coral Sr/Ca reflects SST variation in Ambon Bay well. Based on the reconstructed SST, we found that the SST in Ambon Bay experiences an extreme seasonal variation, which is highly correlated to air temperature, wind speed, and length of sun radiation. Ambon Bay also experiences SST anomalies in some periods, which are dominantly affected by local atmospheric conditions rather than ENSO phenomena
Growth Rates Analysis of Porites Corals from Nusa Penida, Bali
Get PDFThe annual growth of Porites coral is represented by a pair of high- and low-density bands. Environmental changes in the ambient waters influence the pattern of these annual density bands. Five colonies of Porites corals from Nusa Penida, Bali were investigated to analyze their annual linear growth rates using coral densitometry. From the analysis it was found that the annual linear growth rates of the colonies varied between 0.8924 to 1.0012 cm/yr. The trends of the colonies growth rates also varied. Two colonies showed a decreasing trend, while the others showed an increasing trend. The annual linear growth rates of most of the colonies were notinfluenced by sea surface temperature (SST); only one out of five colonies had a significant correlation with SST (R = 0.66, p-value < 0.05)
A Study of Multiple Scattering in BGO and LYSO Single Crystal Scintillators
Get PDFThe angular distribution of multiple Compton scatterings from BGO and LYSO single crystal scintillators was studied at various scattering angles. Gamma photons with 662 keV energy, acquired from a 137Cs source, were used. The scattered photons were detected by a 51mm × 51mm NaI(Tl) scintillation detector. The overall energy correlated to the total number of scattered incidents was analytically reconstructed. The research found that the multiply scattered incidents had the same energy as received from the singly scattered distribution, as the attribution of multiply scattered incidents near the 90° scattering angle revealed. The research results were in agreement with the theoretical calculations