Biologiczna i antyrakowa aktywność wybranych naturalnych produktów

Cancer continues to be one of the major causes of death worldwide. In recent years, the concept of cancer chemoprevention and treatment with natural occurring agents has evolved greatly. In this review work the biological activity and protective effects against cancer of some  natural products - coffee, caffeic acid, caffeic acid phenethyl ester (CAPE), chlorogenic acid, quercetin and curcumin are presented. It seems that the most natural products with anticancer activity act as strong antioxidants and/or modify the activity of one or more protein kinases involved in cell cycle control. The results of in vitro and in vivo studies showed that some of them may be useful as potential chemotherapeutic or chemopreventive anticancer drugs or adjuvants in complex anticancer therapy.Rak pozostaje jedną z głównych przyczyn zgonów na świecie. W ostatnich latach obserwuje się znaczny wzrost zainteresowania chemoprewencją i wykorzystaniem naturalnych produktów w leczeniu schorzeń nowotworowych. W prezentowanej pracy przeglądowej opisano aktywność biologiczną i działanie ochronne przed rakiem wybranych naturalnych produktów, jak: kawa, kwas kawowy, fenylowy ester kwasu kawowego (CAPE), kwas chlorogenowy, kwercetyna i kurkumina. Liczne dane naukowe potwierdzają ich silne działanie przeciwnowotworowe jako przeciwutleniaczy i/lub substancji modyfikujących aktywność kinaz białkowych i wpływających na kontrolę cyklu komórkowego. Wyniki badań in vitro i in vivo wykazały, że niektóre z nich mogą być przydatne jako potencjalne chemiotera-peutyki lub leki chemoprewencyjne w złożonej terapii przeciwnowotworowej

Retardation analytical model to extend service life

A fatigue crack growth model that incorporates crack growth retardation effects and is applicable to the materials characteristics and service environments of high performance LH2/LO2 engine systems is discussed. Future Research plans are outlined

Controlling ion transport through nanopores: modeling transistor behavior

We present a modeling study of a nanopore-based transistor computed by a mean-field continuum theory (Poisson-Nernst-Planck, PNP) and a hybrid method including particle simulation (Local Equilibrium Monte Carlo, LEMC) that is able to take ionic correlations into account including finite size of ions. The model is composed of three regions along the pore axis with the left and right regions determining the ionic species that is the main charge carrier, and the central region tuning the concentration of that species and, thus, the current flowing through the nanopore. We consider a model of small dimensions with the pore radius comparable to the Debye-screening length ($R_{\mathrm{pore}}/\lambda_{\mathrm{D}}\approx 1$), which, together with large surface charges provides a mechanism for creating depletion zones and, thus, controlling ionic current through the device. We report scaling behavior of the device as a function the $R_{\mathrm{pore}}/\lambda_{\mathrm{D}}$ parameter. Qualitative agreement between PNP and LEMC results indicates that mean-field electrostatic effects determine device behavior to the first order

Mathematical modelling and simulations of the ion transport through confined geometries

In this dissertation, we focus on different aspects of modelling ion transport in confined geometries. The transport of the ions through pores was first investigated in the 19th century for cell membranes. In the last years, there has been a significant increase in research of ion transport in nanoscale devices, such as nanopores, nanowires and many more. Especially synthetic pores have the potential to be used as nanoscale diodes, switches or in DNA sequencing. In this thesis, we investigate different modelling approaches and discuss their use and validity in various situations. The transport properties of nanoscale pores are strongly determined by the confined geometry as well as surface charges. Depending on the experimental setup considered finite size, electrostatic as well as electrochemical properties have to be resolved on various scales. This leads to a variety of models ranging from microscopic approaches, such as Molecular Dynamics, to macroscopic models like mean field theory. Since finite size effects and fluid dynamics effects should not be neglected in confined geometries various extensions of the Poisson-Nernst-Planck (PNP) system were introduced in the literature such as density functional theory or the coupling to fluid dynamics. Another challenge in ion transport modelling is the multiscale nature of the synthetic nanopores as their length scale is sometimes 104 times larger than their radial dimension. In the first part of the thesis, we develop a multiscale method that investigates the asymptotic behaviour of the PNP equations for long and narrow nanopores. The significant difference in the radial and lateral length scale allows us to decouple the system and to solve the behaviour in the boundary layers close to the charged pore walls correctly. Two new asymptotic methods were developed to describe the transport problem inside the pore. This asymptotic approximation serves as the basis for the numerical solver. We investigate the quality of the approximations for a variety of pores with different computational experiments. We present comparison of the microscopic quantities such as concentrations and electric potential as well as macroscopic quantities such as current voltage characteristic of exemplary pores. In the second part of the thesis, we compare the simulations of the PNP system with Monte-Carlo methods in the case of ion-channels. We discuss the different modelling assumptions as well as the advantages of both methods. Yet again we present results of the numerical simulations and discuss regimes in which both methods are valid. In the last part, we investigate the optimal control problem for nanopores. Here we want to modify the surface charge of a nanopore to obtain a desired behaviour, such as current-voltage characteristics or rectification behaviour. Two method are derived and implemented as a solution of stated problem

Method of assembling a thermal expansion compensator

A thermal expansion compensator is provided and includes a first electrode structure having a first surface, a second electrode structure having a second surface facing the first surface and an elastic element bonded to the first and second surfaces and including a conductive element by which the first and second electrode structures electrically and/or thermally communicate, the conductive element having a length that is not substantially longer than a distance between the first and second surfaces

Thermal expansion compensator having an elastic conductive element bonded to two facing surfaces

A thermal expansion compensator is provided and includes a first electrode structure having a first surface, a second electrode structure having a second surface facing the first surface and an elastic element bonded to the first and second surfaces and including a conductive element by which the first and second electrode structures electrically and/or thermally communicate, the conductive element having a length that is not substantially longer than a distance between the first and second surfaces

Analysis of the Minimal Promoter from the Hatching Enzyme a Gene

Hatching, defined as a biochemical or biophysical mechanism that allows the embryo to leave its protective envelope, is found in most animals. In fish, reptiles and amphibians, mostly oviparous animals, this means the emergence of the embryo from an egg. In mammals, viviparous animals, hatching is performed by the blastocyst in order to shed the zona pellucida. Fish, an oviparous animal, takes advantage of a biochemical mechanism in order to hatch and emerge from their chorion, or egg envelope. The mechanism includes the use of hatching enzymes that are secreted in order to digest the envelope membrane. The genes controlling the expression of these enzymes are transcribed and translated early in development and are secreted from the animal itself to perform their function. The gene, which controls expression of the protein, is in turn regulated by an upstream region called the promoter. It is the main goal of this project to clone and characterize the minimal promoter of the hatching enzyme gene within the Danio rerio, zebrafish, genome. This fragment will contain all the necessary regulatory elements to bind transcription factors and drive gene expression. The identification and analysis of the minimal promoter of the hatching enzyme gene can lead to the construction of a molecular tool that consists of a short promoter and reporter gene, to be used in conjunction with a variety of genetic screen

High Temperature Stable Nanocrystalline SiGe Thermoelectric Material

A method of forming a nanocomposite thermoelectric material having microstructural stability at temperatures greater than 1000 C. The method includes creating nanocrystalline powder by cryomilling. The method is particularly useful in forming SiGe alloy powder

Transport of solvated ions in nanopores: Asymptotic models and numerical study

Improved Poisson--Nernst--Planck systems taking into account finite ion size and solvation effects provide a more accurate model of electric double layers compared to the classical setting. We introduce and discuss several variants of such improved models. %Based on spatially fully resolved numerical models We study the effect of improved modeling in large aspect ratio nanopores. Moreover, we derive approximate asymptotic models for the improved Poisson--Nernst--Planck systems which can be reduced to one-dimensional systems. In a numerical study, we compare simulation results obtained from solution of the asymptotic 1D-models with those obtained by discretization of the full resolution models