Fourier Domain Optical Coherence Tomography for Simultaneous Measurement of Refractive Index and Physical Thickness of Multiple layers

In fourier domain optical coherence tomography, we can measure the optical thickness ( refractive index n times thickness d), to obtain the retinal layers in order to diagnose many disorders. In this work, we introduce a new method for measurement of refractive index and physical thickness of multiple layers simultaneously by Fourier domain optical coherence tomography, without additional information about the structure of the sample under investigation. The input data to the formulation are the interference spectrum of FD-OCT system and the optical path lengths (OPLs) which obtain from fast fourier transform of interference spectrum. The output of simulation suggest that, the accuracy of the extracted parameters depend on the difference in the refractive index gradient of sample interfaces. Furthermore, we show that the accuracy of the extracted parameters can be affected by uncertainty in obtained OPLs. So, we introduce a method to optimize the accuracy of parameters in spite of uncertainty in measuring OPLs. Simulation results show that, for transparent biological sample merge into an aqueous media, if sample layers has indices less than 1.55 , these parameters can be extracted with the , less than 0.001

Prevalence of medicinal drug interactionsin medicinal prescriptions in the Golestan province, Iran (2012)

Background and Objective: Medicinal drug interactions are one of the problems caused by irrational drug prescription. It eigher change the therapeutic effect or cause drug toxicity. This study was performed to determine the prevalence of medicinal drug interactions in medicinal prescriptions in Golestan province, north of Iran. Methods: In this descriptive study, 1100000 medicinal prescriptions under contract with the Golestan province health insurance organization were assessed for drug interactions during 20 March- 20 September 2012. Results: Drug interactions frequency was 6262 (0.66%). 35.5%, 63.1% and 1.4% of prescriptions were severe, moderate and mild interactions, respectively. The most common severe, moderate and mild drug interactions related to Atorvastatin-Gemfibrozil (13.67%), Ceftriaxone- Gentamicin (9.05%) and Lithium Carbonate-Haloperidol (2.56%). Conclusion: In view of moderate and severe medicinal drug interactions in physicians' prescriptions, health system should plan a comprehensive program to improve awareness and effective monitoring to reduce medicinal drug interactions