New type of ellipsometry in infrared spectroscopy: The double-reference method

We have developed a conceptually new type of ellipsometry which allows the determination of the complex refractive index by simultaneously measuring the unpolarized normal-incidence reflectivity relative to the vacuum and to another reference media. From these two quantities the complex optical response can be directly obtained without Kramers-Kronig transformation. Due to its transparency and large refractive index over a broad range of the spectrum, from the far-infrared to the soft ultraviolet region, diamond can be ideally used as a second reference. The experimental arrangement is rather simple compared to other ellipsometric techniques.Comment: submitted to Appl. Phys. Let

The Effect of Colcemid on the Heat Survival of Mitotic V79 Chinese Hamster Cells

V79 Chinese hamster cells were collected by colcemid addition to study the effect of heat on mitosis. When they were heated at 42°C and 45°C in the presence of 0.06 μg/mL colcemid, cell survival increased over the control samples, which were heated in ordinary medium. Scanning electron microscopy showed that cells heated to 45°C in the presence or absence of colcemid had fewer microvilli on the surface, but they did not have increased bleb formation. Transmission electron microscopy showed that the chromatin was diffuse in the heated cells and the kinetochores were indistinct. The mitochondria in the heated cells were also swollen and contained visible particles

Therapeutic effect of antimyeloma antibodies conjugated with gold nanoparticles on the growth of myeloma cell line

Nanobiotechnology is a field of biomedical application of nanosize system which is a rapidly developing area within nanotechnology among these nonmaterial, gold nanoparticles (AuNPs) which receive a significant attention due to their unique physical, chemical and biological properties. AuNPs and bio-conjugated AuNPs have been widely used in cancer treatment besides other application on cancer detection and diagnosis. In this study the potential therapeutic effects of polyclonal Antimyeloma antibody (AbMM) conjugated to AuNPs in comparison with naked (AbMM) or AuNPs alone in modulation of proliferation capacity in vitro and different stages of MM cell cycle have been evaluated besides evaluation of their effects on tumor growth delay. Effect of AuNPs , (AbMM) and (Nanogold -Antimyeloma Antibodies conjugate) (gold-AbMM) on growth of myeloma cells showed decreasing in multiple myeloma SP2OR (MM) viability with increasing dose of these treatments compared to that of control also a significant enhancement in the apoptosis after conjugation of Nanogold to the Antimyeloma was observed. The induction of apoptosis with gold-AbMM was significantly higher than the MM cells exposed to only AbMM or AuNPs. The study concluded that the efficacy of (gold-AbMM) on induced myeloma growth inhibition is better than that of individual AuNPs and AbMM

Constructing Fresnel reflection coefficients by ruler and compass

A simple and intuitive geometical method to analyze Fresnel formulas is presented. It applies to transparent media and is valid for perpendicular and parallel polarizations. The approach gives a graphical characterization particularly simple of the critical and Brewster angles. It also provides an interpretation of the relation between the reflection coefficients for both basic polarizations as a symmetry in the plane

Low-temperature far-infrared ellipsometry of convergent beam

Development of an ellipsometry to the case of a coherent far infrared irradiation, low temperatures and small samples is described, including a decision of the direct and inverse problems of the convergent beam ellipsometry for an arbitrary wavelength, measurement technique and a compensating orientation of cryostat windows. Experimental results are presented: for a gold film and UBe13 single crystal at room temperature (lambda=119 um), temperature dependencies of the complex dielectric function of SrTiO3 (lambda=119, 84 and 28 um) and of YBa2Cu3O7-delta ceramic (lambda=119 um).Comment: 14 pages, 6 figure

Fresnel coefficients as hyperbolic rotations

We describe the action of a plane interface between two semi-infinite media in terms of a transfer matrix. We find a remarkably simple factorization of this matrix, which enables us to express the Fresnel coefficients as a hyperbolic rotation.Comment: 6 pages, 3 figure

Iwasawa Effects in Multi-layer Optics

There are many two-by-two matrices in layer optics. It is shown that they can be formulated in terms of a three-parameter group whose algebraic property is the same as the group of Lorentz transformations in a space with two space-like and one time-like dimensions, or the $Sp(2)$ group which is a standard theoretical tool in optics. Among the interesting mathematical properties of this group, the Iwasawa decomposition drastically simplifies the matrix algebra under certain conditions, and leads to a concise expression for the S-matrix for transmitted and reflected rays. It is shown that the Iwasawa effect can be observed in multi-layer optics, and a sample calculation of the S-matrix is given.Comment: RevTex 10 pages including 1 psfi

Assessment of genetic diversity of zoonotic Brucella spp. recovered from livestock in Egypt using multiple locus VNTR analysis

Brucellosis is endemic in most parts of Egypt, where it is caused mainly by Brucella melitensis biovar 3, and affects cattle and small ruminants in spite of ongoing efforts devoted to its control. Knowledge of the predominant Brucella species/strains circulating in a region is a prerequisite of a brucellosis control strategy. For this reason a study aiming at the evaluation of the phenotypic and genetic heterogeneity of a panel of 17 Brucella spp. isolates recovered from domestic ruminants (cattle, buffalo, sheep, and goat) from four governorates during a period of five years (2002-2007) was carried out using microbiological tests and molecular biology techniques (PCR, MLVA-15, and sequencing). Thirteen strains were identified as B. melitensis biovar 3 while all phenotypic and genetic techniques classified the remaining isolates as B. abortus (n = 2) and B. suis biovar 1 (n = 2). MLVA-15 yielded a high discriminatory power (h = 0.801), indicating a high genetic diversity among the B. melitensis strains circulating among domestic ruminants in Egypt. This is the first report of the isolation of B. suis from cattle in Egypt which, coupled with the finding of B. abortus, suggests a potential role of livestock as reservoirs of several zoonotic Brucella species in the region

Flat photonic bands in guided modes of textured metallic microcavities

M. G. Salt and William L. Barnes, Physical Review B, Vol. 61, pp. 11125-11135 (2000). "Copyright © 2000 by the American Physical Society."A detailed experimental study of how wavelength-scale periodic texture modifies the dispersion of the guided modes of λ/2 metal-clad microcavities is presented. We first examine the case of a solid-state microcavity textured with a single, periodic corrugation. We explore how the depth of the corrugation and the waveguide thickness affect the width of the band gap produced in the dispersion of the guided modes by Bragg scattering off the periodic structure. We demonstrate that the majority of the corrugation depths studied dramatically modify the dispersion of the lowest-order cavity mode to produce a series of substantially flat bands. From measurements of how the central frequency of the band gap varies with direction of propagation of the guided modes, we determine a suitable two-dimensional texture profile for the production of a complete band gap in all directions of propagation. We then experimentally examine band gaps produced in the guided modes of such a two-dimensionally textured microcavity and demonstrate the existence of a complete band gap for all directions of propagation of the lowest-order TE-polarized mode. We compare our experimental results with those from a theoretical model and find good agreement. Implications of these results for emissive microcavity devices such as light-emitting diodes are discussed