Photonic Crystal and Photonic Crystal Fibers Communications

The development of all optical communications could benefit from the index guiding photonic crystal fibers. In communication the photonic crystal fibers could provide many new solutions. Conventional optical fibers have within the last decades revolutionized the communications industry and it is today a mature technology being pushed to its limit with respect to properties such as losses, single mode operation and dispersion. The spectra have been used by others to develop optical frequency standards. The process can potentially be used for frequency conversion in fiber optic network. In this system the dispersive properties can be controlled by the optical lattice making it possible to achieve phase-matched four wave mixing, like look the process taking place in the photonic crystal fibers. In this paper we will discuss the use of photonic crystal fibers in communications

The Advantages of Using Photonic Crystal Fibers Instead of the Conventional Fibers in Optical Gyroscope

In this paper we proposed to use of a hollow core photonic crystal fiber 1550nmλ , Ø10 µm instead of the conventional fibers in optical gyroscope .Two beams are again propagating through the fiber in opposite directions. Due to the Sagnac effect, the beam travelling against the rotation experiences a slightly shorter path delay than the other beam. The resulting differential phase shift is measured through interferometry, thus translating one component of the angular velocity into a shift of the interference pattern which is measured photometrically. Photonic crystal fibers present special properties and capabilities that lead to an outstanding potential for sensing applications according to these features we can elimination a lot of the problems that exist in the conventional fiber optic gyroscope and getting better and more accurate results in the same conditions when using Photonic Crystal Fibers

Nonlinear Wave Propagation in Photonic Crystal Fibers

Wave propagation is a fundamental phenomenon occurring in several physical systems. The spectra have been used by others to develop optical frequency standards. The process can potentially be used for frequency conversion in fiber optic network. In this system the dispersive properties can be controlled by the optical lattice making it possible to achieve phase-matched four wave mixing, like look the process taking place in the photonic crystal fibers (PCFs). In this paper will focus on two such systems the propagation nonlinear wave in photonic crystal fibers and the propagation of matter waves in optical lattices

Inflammatory Mechanisms in the Regulation of Insulin Resistance

Insulin resistance (IR) plays a key role in the pathophysiology of obesity-related diseases such as type 2 diabetes and nonalcoholic fatty liver disease. It has been demonstrated that IR is associated with a state of chronic low-grade inflammation, and several mediators released from various cell types, including immune cells and adipocytes, have been identified as being involved in the development of IR. Among those are several pro-inflammatory cytokines such as tumor necrosis factor-α(TNF-α), interleukin (IL)-1, IL-6, and various adipocytokines. Furthermore, several transcription factors and kinases such as c-Jun N-terminal kinase (JNK) and inhibitor of kappa B kinase-β (IKKβ), a kinase located proximal of nuclear factor-κB (NF-κB), participate in this process. Hepatocyte-specific overexpression of NF-κB is associated with IR and can mimic all features of fatty liver disease. Whereas the evidence for an important role of many pro-inflammatory pathways in IR in in vitro and animal studies is overwhelming, data from interventional studies in humans to prove this concept are still minor. As a complex network of inflammatory cytokines, adipocytokines, transcription factors, receptor molecules, and acute-phase reactants are involved in the development of IR, new therapeutic approaches in IR-related diseases will be based on a better understanding of their complex interactions

Adipokines and Insulin Resistance

Obesity is associated with an array of health problems in adult and pediatric populations. Understanding the pathogenesis of obesity and its metabolic sequelae has advanced rapidly over the past decades. Adipose tissue represents an active endocrine organ that, in addition to regulating fat mass and nutrient homeostasis, releases a large number of bioactive mediators (adipokines) that signal to organs of metabolic importance including brain, liver, skeletal muscle, and the immune system—thereby modulating hemostasis, blood pressure, lipid and glucose metabolism, inflammation, and atherosclerosis. In the present review, we summarize current data on the effect of the adipose tissue-derived hormones adiponectin, chemerin, leptin, omentin, resistin, retinol binding protein 4, tumor necrosis factor-α and interleukin-6, vaspin, and visfatin on insulin resistance