Processing sequences of chromatophore images with application to a signal transduction pathway modeling

Systems biology is becoming increasingly important for the study of living organisms. It focuses on the mathematical understanding of biological systems. Cells, the basic units of all living creatures, are biological systems of major interest. Considerable work is being done towards modeling cells as mathematical systems. At the same time, great effort has been made in an attempt to use chromatophore cells as biosensors for various substances. The results of changes in these cells induced by various substances can be seen under the microscope. Therefore, efficient digital image and video processing algorithms are required to help extract these changes. This dissertation establishes a link between the biological aspect of chromatophores and digital image/video processing techniques used for chromatophore characterization. A complete model of the Gs-AC-PKA-granule motion signal transduction pathway is proposed, starting from the input ligand and ending in features extracted from the microscope image. The model is developed by extending an existing system biology differential equation based model of the Gs—AC—PKA transduction pathway obtained from the Database of Quantitative Cellular Signaling (DQCS). The extension of the mode! is founded on physical assumptions about the dynamic behavior of pigment granules as well as on image feature extraction. Several image and video processing methods have been either newly developed or adapted for the characterization of pigment granule distribution images. Examples are presented to demonstrate the effectiveness of the developed image processing methods and of the proposed system model.Keywords: Chromatophores, Image/video processing, System biology, Cell modelin

Nonlinear full wave time domain solutions using FDTD_SPICE for high speed digital

Abstract With high speed digital designs extending well into the GHz range, quasi-static and TEM solutions are no longer valid. Digital designers like to see time domain waveforms as provided by SPICE. However, full wave effects are often accounted for only by frequency domain electromagnetic solvers. A simulator that combines FDTD and SPICE is used in this paper as a solution to this problem. The nonlinear circuit elements are simulated in SPICE and the structural elements in FDTD. The simulators are tightly integrated and talk to each other at each time-step. The approach is used to analyze difficult problems such as meanders, ground bounce and placement of decoupling capacitors in a PCB, and dispersion in microstrips. Authors/Speakers Neven Orhanovic Current Activities He is currently with Applied Simulation Technology working on time domain full wave methods. Backgroun

Signal Propagation and Radiation of Single and Differential Microstrip Traces Over Split Image Planes

Abstract: This paper deals with the effect of split power or ground planes on single and differential signals propagating on microstrip structures using the FDTD method. The effect of the split in the image plane on the propagated signals as well as on the radiated fields is examined for different trace separations. The improvement of signal quality and the reduction of the unwanted radiation obtained by running tightly coupled differential traces over the split is examined. The excitation of slot line modes in the split is shown

Photochemical reductive elimination of hexabromotellurate(IV)

In the region between 500 nm and 300 nm the electronic spectrum of [TeBr6]2− displays absorptions which are assigned to s → p transitions. At shorter wavelengths ligand-to-metal charge transfer (LMCT) bands appear. Irradiation of [TeBr6]2− in acetonitrile led to a reductive elimination according to the equation [TeBr6]2− → [TeBr4]2− + Br2. Upon LMCT excitation (λirr = 254 nm) the quantum yield was Φ = 1.3 × 10−2 but decreased when the light was absorbed by the longer-wavelength sp bands (Φ = 0.7 × 10−3 at λirr = 436 nm)

Anisakis pegreffii (Nematoda: Anisakidae) products modulate oxidative stress and apoptosis-related biomarkers in human cell lines

Background In countries with elevated prevalence of zoonotic anisakiasis and high awareness of this parasitosis, a considerable number of cases that associate Anisakis sp. (Nematoda, Anisakidae) and different bowel carcinomas have been described. Although neoplasia and embedded larvae were observed sharing the common site affected by chronic inflammation, no association between the nematode and malignancy were directly proved. Similarly, no data are available about the effect of secretory and excretory products of infecting larvae at the host\u2019s cellular level, except in respect to allergenic interaction. Methods To test the mechanisms by which human non-immune cells respond to the larvae, we exposed the fibroblast cell line HS-68 to two Anisakis products (ES, excretory/secretory products; and EC, crude extract) and evaluated molecular markers related to stress response, oxidative stress, inflammation and apoptosis, such as p53, HSP70, TNF-\u3b1, c-jun and c-fos, employing cell viability assay, spectrophotometry, immunoblotting and qPCR. Results Both Anisakis products led to increased production of reactive oxygen species (ROS), especially in EC-treated cells. While the ES treatment induces activation of kinases suggesting inflammation and cell proliferation (or inhibition of apoptosis), in EC-treated cells, other signaling pathways indicate the inhibition of apoptosis, marked by strong upregulation of Hsp70. Elevated induction of p53 in fibroblasts treated by both Anisakis products, suggests a significantly negative effect on the host DNA. Conclusions This study shows that in vitro cell response to Anisakis products can result in at least two different scenarios, which in both cases lead to inflammation and DNA damage. Although these preliminary results are far from proving a relationship between the parasite and cancer, they are the first to support the existence of conditions where such changes are feasible