Estimation of optical abnormalities in breast phantom by diffuse equation

Optical imaging is an emerging method for bio-imaging. The advantages of this imaging provide non-ionizing and safe radiation, non-invasive and functional medical imaging. Due to diffusion of photons inside biological tissues, its image processing is complicated. So in spite of these advantages, this imaging method has not been progressed like ultrasound imaging and magnetic resonance imaging (MRI). Also, the penetration depth of photons inside biological phantom is low. To overcome this problem, the complicated diffusion of photons through tissue must be modeled. The diffuse equation can be applied to simulate photons through turbid media like biological tissues. In this paper, the diffuse equation is used to study propagation of diffuse photons. The green function method is applied to solve this equation, and then the optical properties of abnormalities in breast phantom are estimated. This fast method can be applied for image processing.     

The numerical and experimental study of photon diffusion inside biological tissue using boundary integral method

In this study, the diffusion of photons in turbid media, like biological tissue has been studied. Due to scattering and absorption of photons in such media, the study of photon propagation in biological tissue is complicated. The several numerical methods have been presented to simulate the behavior of diffused photons. Recently, Boundary Integral Method (BIM) has been offered to simulate photon migration inside biological tissues. This method has advantage, e.g. lower computational time in compared with other numerical methods. In this study, the accuracy and precision of BIM compares with another numerical method like Monte Carlo technique and finite difference method, and also the calculated results obtained by BIM and Monte Carlo method evaluate with measured results. Furthermore, the effects of scattering and absorption coefficient of tissue on the measured signal are studied.     

Synthesis and Characterization of 8-hydroxyquinoline Complexes of Tin(IV) and Their Application in Organic Light Emitting Diode

A series of 8-hydroxyquinoline complexes of tin, Q(2)SnCl(2) (Q?=?2-methyl-8-hydroxyquinoline, 8-hydroxyquinoline, 5,7-dibromo-8-hydroxyquinoline, 5-chloro-8-hydroxyquinoline, 5,7-dichloro-8-hydroxyquinoline and 5-nitro-8-hydroxyquinoline) were prepared by reacting stannous dichloride with 8-hydroxyquinoline and its derivatives. All complexes were characterized by elemental analysis, mass spectrometry and infrared, UV-vis and (1)H NMR spectroscopes. Furthermore, the molecular structure of a representative complex, dichlorido-bis(5-nitro-quinolin-8-olato-2N,O)tin(IV), was determined by single-crystal X-ray diffraction. The photoluminescence (PL) properties of all prepared compounds and electroluminescence (EL) property of a selected complex (Q?=?5-chloro-8-hydroxyquinoline) were investigated. The results showed that the emission wavelength can be tuned by electron donating or withdrawing group substituent on 8-hydroxyquinoline. Application of prepared complexes in fabrication of an OLED has been demonstrated.     

The estimation of a unique solution for steady-state diffuse optical tomography by applying mechanical pressure

The accuracy of diffuse optical tomography (DOT) highly depends on two important factors: first, the knowledge of the tissue optical heterogeneities for accurate modeling of light propagation, and second, the uniqueness of reconstructed values of optical properties. Previous studies illustrated that the inverse problem associated with steady-state DOT does not have unique solutions. In this study, we propose a simple method that can be applied to improve this challenging problem of steady-state DOT. In this method, we study the propagation of photons through compressed breast phantoms. The applied mechanical pressure can change the values of optical properties and this pressure dependence of optical properties as a set of constraint equations can be used to improve the inverse problem. The applied pressure can help us to restrict the distribution of possible values of depth and radius of defect inside breast phantom reconstructed by inverse problem.     

Effects of different light irradiations on structure and optical properties of methoxy-substituted tetraphenylporphyrins

UV lamp, filtered halogen lamp (at 425 nm) and Green laser (532 nm) experiments on a series of meso-substituted tetra phenyl porphyrin, TPP, bearing methoxy peripheral groups together with a metal derivate of 3,4 dimethoxy TPP were lead to different protonation and aggregation structures. Properties of irradiated porphyrins were investigated using their absorption and emission spectra in dichloromethane solution. The results show that the optical properties of the TPP derivates depend on light irradiation source, which shows the tuning of the absorption and emission spectra of the TPP derivates. From the dynamic light scattering measurements, the size distribution of samples was estimated about 5–15 nm in solvent after irradiation. Atomic force microscopy images of deposited porphyrins on the glass surface were shown average particle size between 10 and 30 nm. Particularly, self-assembly of the porphyrin derivates was also observed when green laser was used. We suggest that the irradiation source plays an important role in the controlling of size and morphology of products, and we propose a self-organization model to explain the formation of the porphyrin nanostructures.     

Color optimization of red OLEDs via periodic and gradient deposition rate of fluorescent dopants

Optical and Quantum Electronics - This paper deals with the 700 keV energetic Carbon (C) ions irradiations induced structrual modification and optical bandgap tunning of...     

Red organic light emitting device based on TPP and a new host material

A novel coating method for fabrication of red OLEDs by using a new host material has been developed with the aid of a single furnace. The host material, zinc complex, was prepared from the reaction of zinc acetate and 2-methyl-8-hydroxyquinoline and after characterization by UV-vis, FT-IR, and ¹H NMR spectroscopes was used as an emitting material in the fabrication of OLEDs. Since meso-tetraphenylporphyrin (TPP) and zinc complex have a close molecular weight, both materials were evaporated from a single furnace. Devices with TPP and structures of ITO/PEDOT:PSS (55 nm)/PVK (90 nm)/zinc complex:TPP (65 nm)/Al (180 nm) were fabricated; Without TPP green and with TPP red emission was achieved. The device with 2 % TPP that doped into the zinc complex showed the purest red emission among all devices. The device showed the CIE coordinates of 0.70 and 0.28 at 14 V and a maximum luminance of about 94.2 cd/m². This new method is a promising candidate for fabrication of low cost red OLEDs with a more homogeneous layer.