Dr. Jekyll and Mr. Hyde - Distinctiveness and plasticity of mononuclear phagocytes in the mouse skin

Antigen-presenting cells are crucial participants in the defense of the body against potentially pathogenic invaders. In an immature state, they reside in all peripheral sites, where they can recognize and take up antigens. Once they have encountered antigens, they may become activated. As a consequence, they will migrate to draining lymph nodes, where they can activate naïve T cells to become the main effector cells of the immune system. These T cells can then migrate back to the affected site to help to rid the body of the invaders. The skin, as the largest organ of the body, contains many cells that have the potential to develop into effective antigen-presenting cells (discussed in Chapters 1 and 2). The epidermis, the outermost layer, has its population of Langerhans cells. These cells form a tight network with connecting cellular protrusions. Via these, they sample endogenous as well as exogenous molecules that get into contact with the epidermis. As these cells have been known now for quite a while, their functions in the epidemis as well as after migration into skin-draining lymph nodes have been extensively studied. The dermis, the second layer of the skin, also contains cells with potential antigenpresenting capacity. These cells are, in contrast to the epidermal Langerhans cells, much less well investigated. The aim of this thesis study, outlined in Chapter 3, therefore was to analyze the antigen-presenting cells of the mouse dermis in more detail and to compare them to the epidermis-derived Langerhans cells

European economic and monetary union: Background and implications

The European Union, which currently consists of 15 states, occupies an important place among the advanced economies. The final stage of the European economic and monetary union (EMU) is scheduled to begin in January 1999 with the adoption of a common currency called the "euro." A decision on which countries will participate in the euro area in 1999 will be made next spring based in part on the achievement of the economic criteria laid out in the Maastricht Treaty. In this article, the authors, after a brief discussion of the historical background, cast some light on the institutional aspects of the EMU, on the formulation and implementation of economic policy, as well as on the internal and external effects of EMU completion. For Canada, the direct implications of the shift to the euro appear to be relatively modest, at least in the short run.

On the Privacy of Encrypted Skype Communications

The privacy of voice over IP (VoIP) systems is achieved by compressing and encrypting the sampled data. This paper investigates in detail the leakage of information from Skype, a widely used VoIP application. In this research, it has been demonstrated by using the dynamic time warping (DTW) algorithm, that sentences can be identified with an accuracy of 60%. The results can be further improved by choosing specific training data. An approach involving the Kalman filter is proposed to extract the kernel of all training signals

Dendritic cells in vivo and in vitro

Dendritic cells (DC) are crucial cells of the immune system, and bridge the essential connection between innate and adaptive immunity. They reside in the periphery as sentinels where they take up antigens. Upon activation, they migrate to lymphoid organs and present there the processed antigens to T cells, thereby activating them and eliciting a potent immune response. Dendritic cells are bone marrow-derived cells, still big controversies exist about their in vivo development. In vitro, DC can be generated from multiple precursor cells, among them lymphoid and myeloid committed progenitors. Although it remains unknown how DC are generated in vivo, studying the functions of in vitro generated DC results in fundamental knowledge of the DC biology with promising applications for future medicine. Therefore, in this review, we present current protocols for the generation of DC from precursors in vitro. We will do this for the mouse system, where most research occurs and for the human system, where research concentrates on implementing DC biology in disease treatments

Agenda 21 local como herramienta de desarollo sostenible : La situación en Suiza

1999an Suitzak bere konpromisoa bete zuen, garapen iraunkorra Konstituzioan barneratu baitzuen. Herrialde hau Tokiko Agenda 21 delakoaren moduko prozesu zehatzak sustatzeko hainbat estrategia ari da probatzen. 2005eko uztailean, Suitzako udalerrien % 4 baino ez zegoen prozesu honetan sartuta; hau da, biztanleriaren % 29. Suitzako tokiko agintaritzek, sistema federala dela eta, autonomia handia izan dute aspalditik; gainera, biztanleek demokrazia zuzeneko sistema suitzarraren bidez, Europako beste herrialde batzuetan baino zuzenago parte har dezakete erabaki politikoak hartzerakoan. Epe luzera, Garapen Iraunkorreko Estrategia Nazionalaren helburua garapen iraunkorra agintari publikoen jarduera eta politika guztietan barneratzea da.In 1999, Switzerland made good its pledge by writing sustainable development into its Constitution. Different strategies and programs are going on to promote Agenda 21-like processes. In July 2005, just 4% of municipalities were involved in the process, though this does represent 29% of the population. In Switzerland, under the country¿s federal system, local authorities have for a long time enjoyed considerable autonomy and, under the Swiss system of direct democracy, citizens are able to participate more fully in all political decision-making than in other countries. In the longer term, the aim of the National Sustainable development Strategy is to include sustainable development in all the policies and activities of public authorities.En 1999, Suiza cumplió con su compromiso al incluir el desarrollo sostenible en la Constitución. Este país está ensayando diferentes estrategias para fomentar determinados procesos del estilo de la Agenda 21 Local. En julio de 2005, tan sólo un 4% de los municipios suizos se habían involucrado en este proceso, si bien representan un 29% de la población. Las autoridades locales suizas, bajo un sistema federal, han disfrutado durante mucho tiempo de una autonomía considerable. Y los ciudadanos, mediante el sistema suizo de democracia directa, pueden participar de una manera más activa que en otros países europeos en la toma de decisiones políticas. A largo plazo, el objetivo de la Estrategia Nacional de Desarrollo Sostenible es incluir el desarrollo sostenible en todas las actividades y políticas de las autoridades pública

Analysis of electron-positron momentum spectra of metallic alloys as supported by first-principles calculations

Electron-positron momentum distributions measured by the coincidence Doppler broadening method can be used in the chemical analysis of the annihilation environment, typically a vacancy-impurity complex in a solid. In the present work, we study possibilities for a quantitative analysis, i.e., for distinguishing the average numbers of different atomic species around the defect. First-principles electronic structure calculations self-consistently determining electron and positron densities and ion positions are performed for vacancy-solute complexes in Al-Cu, Al-Mg-Cu, and Al-Mg-Cu-Ag alloys. The ensuing simulated coincidence Doppler broadening spectra are compared with measured ones for defect identification. A linear fitting procedure, which uses the spectra for positrons trapped at vacancies in pure constituent metals as components, has previously been employed to find the relative percentages of different atomic species around the vacancy [A. Somoza et al. Phys. Rev. B 65, 094107 (2002)]. We test the reliability of the procedure by the help of first-principles results for vacancy-solute complexes and vacancies in constituent metals.Comment: Submitted to Physical Review B on September 19 2006. Revised version submitted on November 8 2006. Published on February 14 200

Investigation of the chemical vicinity of crystal defects in ion-irradiated Mg and AZ31 with coincident Doppler broadening spectroscopy

Crystal defects in magnesium and magnesium based alloys like AZ31 are of major importance for the understanding of their macroscopic properties. We have investigated defects and their chemical surrounding in Mg and AZ31 on an atomic scale with Doppler broadening spectroscopy of the positron annihilation radiation. In these Doppler spectra the chemical information and the defect contribution have to be thoroughly separated. For this reason samples of annealed Mg were irradiated with Mg-ions in order to create exclusively defects. In addition Al- and Zn-ion irradiation on Mg-samples was performed in order to create samples with defects and impurity atoms. The ion irradiated area on the samples was investigated with laterally and depth resolved positron Doppler broadening spectroscopy (DBS) and compared with preceding SRIM-simulations of the vacancy distribution, which are in excellent agreement. The investigation of the chemical vicinity of crystal defects in AZ31 was performed with coincident Doppler broadening spectroscopy (CDBS) by comparing Mg-ion irradiated AZ31 with Mg-ion irradiated Mg. No formation of solute-vacancy complexes was found due to the ion irradiation, despite the high defect mobility.Comment: Submitted to Physical Review B on March 20 20076. Revised version submitted on September 28 2007. Accepted on October 19 200

Nonpolar optical scattering of positronium in magnesium fluoride

We report the results of the analysis of the temperature broadening of the momentum distribution of delocalized Positronium (Ps) in Magnesium Fluoride in terms of optical deformation-potential scattering model (long-wavelength optical phonons). The Ps optical deformation-potential coupling constant $D_{o}$ in MgF$_{2}$ has been determined to be $(1.8\pm0.3)\times10^{9}$ eV/cm. We also show that the Ps momentum distribution is sensitive to second-order phase transitions in those crystals where optical deformation-potential scattering is allowed in one and forbidden in another crystalline phase

Cancellation of probe effects in measurements of spin polarized momentum density by electron positron annihilation

Measurements of the two dimensional angular correlation of the electron-positron annihilation radiation have been done in the past to detect the momentum spin density and the Fermi surface. We point out that the momentum spin density and the Fermi Surface of ferromagnetic metals can be revealed within great detail owing to the large cancellation of the electron-positron matrix elements which in paramagnetic multiatomic systems plague the interpretation of the experiments. We prove our conjecture by calculating the momentum spin density and the Fermi surface of the half metal CrO2, who has received large attention due to its possible applications as spintronics material

The federal Equal Rights Amendment : projected effects based on interpretation of state ERAs

Even a brief examination of the history of the United States, the “Home of the Free,” and the “Land of Opportunity,” reveals that, for any number of practical purposes, the United States has been the home of the free as well as the home of the oppressed and the land of limited opportunity for all but a select few. Legislative innovations of the past few decades have gone far in attempting to alleviate some of the inequalities which plague our nation. However, many of these attempts, admirable as they may be, have fallen far short of their aims. The Civil Rights Act of 1964, for example, attacked legislatively protected racial discrimination. The status of non-white Americans, however, remains second class by many standards