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Shrew-1 wurde bei der Suche invasivitätsassoziierter Gene mittels eines DDRT-PCR-Ansatzes aus invasiven Zellen isoliert. Wie computergestützte Analysen der Sequenz ergaben, wies das bis dahin unbekannte Protein keinerlei Ähnlichkeiten mit bereits bekannten Proteinen auf und homologe Proteine wurden bisher nur in Vertebraten gefunden. Expressionsanalysen mit einem GFP-markierten shrew-1 zeigten, dass es an der basolateralen Plasmamembran lokalisiert, wo es mit dem E-Cadherin vermittelten Adhäsions-Komplex kolokalisiert. Eine Integration in diesen Komplex geschieht höchstwahrscheinlich durch direkte Interaktion mit β-Catenin. Ein weiteres Molekül das als potenzieller Interaktionspartner von shrew-1 identifiziert wurde und das in der Literatur oft als Tumorsuppressor diskutiert wird, ist Caveolin-1. Ferner konnten Überexpressionexperimente bereits zeigen, dass shrew-1 die Invasivität von HT1080-Zellen erhöhen kann. Das Ziel dieser Arbeit war es, zum einen mit Hilfe des Hefe-Split-Ubiquitin-Systems eine Interaktion von shrew-1 und Caveolin-1 zu bestätigen und zum anderen neue Interaktionspartner zu identifizieren, die helfen könnten, die Rolle von shrew-1 in invasiven Vorgängen zu erklären. Um eine mögliche Verbindung von shrew-1 und einem neuen Interaktionspartner in Bezug auf die Zellinvasivität zu untersuchen, sollten sowohl shrew-1 als auch der potenzielle Interaktionspartner mittels RNAi ausgeschaltet werden. Mit Hilfe des Split-Ubiquitin-Systems war es möglich, die Interaktion zwischen shrew-1 und caveolin-1 zu bestätigen und zu zeigen, dass diese durch die zytoplasmatische Domäne von shrew-1 vermittelt wird. Weiterhin konnte CD147 als neuer Interaktionpartner identifiziert werden. Eine Interaktion beider Proteine konnte ferner mit Hilfe des Bimolekularen-Fluoreszens-Komplementations-Systems (BIFC), des Fluoreszens-Resonanz-Energie-Transfers (FRET) und Coimmunoprezipitationen bestätigt werden. Die Interaktion von shrew-1 und CD147 scheint allerdings abhängig vom zellulären Kontext zu sein, wie die FRET-Analysen vermuten lassen. So konnte nämlich mit diesen Analysen eine starke Interaktion in MCF7-Zellen gezeigt werden, wohingegen die Interaktion in MDCK-Zellen schwächer war. Einer der auffälligsten Unterschiede dieser beiden Zelllinien im Bezug auf diese Interaktion könnte sein, dass MCF7-Zellen im Gegensatz zu MDCK-Zellen kein Caveolin-1 exprimieren. Caveolin-1 konnte seinerseits als Interaktionspartner von shrew-1 mit Hilfe des Hefe-Split-Ubiquitin-Systems bestätigt werden und andererseits wurde von einer anderen Arbeitsgruppe eine Interaktion von CD147 mit Caveolin-1 publiziert. Um dies näher zu untersuchen, wurde Caveolin-1 in MCF7-Zellen exprimiert und die FRET-Analysen in diesen wiederholt. Wie vermutet kam es zu einer Reduktion der Interaktion in Caveolin-1 exprimierenden MCF7-Zellen. CD147 ist neben vielen anderen Funktionen auch maßgeblich an der Regulation von Matrix-Metalloproteinasen beteiligt und kann somit die Invasivität von Zellen beeinflussen. Um einen Einfluß von shrew-1 und CD147 auf die Invasivität zu untersuchen, wurden beide Proteine mittels RNAi in HeLa-Zellen ausgeschaltet. Nachdem ein negativer Einfluss dieses Ansatzes auf das Proliferationsverhalten der Zellen ausgeschlossen werden konnte, wurde ein möglicher Effekt auf die Invasivität der Zellen untersucht. Durch die Analyse in Matrigel-Invasionsassays konnte gezeigt werden, dass das unabhängige Ausschalten beider Proteine die Invasivität der Zellen auf 35-55% im Vergleich zu Kontrollzellen reduziert. Die Ergebnisse dieser Arbeit untermauern die Annahme, dass shrew-1 eine Rolle bei invasiven Vorgängen spielt und weisen darauf hin, dass dies möglicherweise durch eine Interaktion mit CD147 geschieht. Die Interaktion mit CD147 und damit eine mögliche Funktion von shrew-1 bei invasiven Vorgängen scheinen dabei abhängig vom zellulären Kontext zu sein.
Das E-Finance Lab publiziert jeweils quartalsweise einen digitalen sowie einen gedruckten Newsletter, die abwechselnd alle sechs Wochen erscheinen. Der digitale Newsletter gibt einen kurzen Überblick über ausgewählte Forschungsarbeiten und nutzt den Einsatz von Hyperlinks zu weiterführenden Informationen. s. http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hebis:30:3-15886 . Der gedruckte Newsletter "EFL quarterly : an E-Finance Lab publication" hingegen beschreibt kompakt und ergebnisorientiert einzelne Forschungsprojekte.
The article explores the increasing gap between the cultural dynamics of transnationalization in Germany and the national self-perception of the German society. While concepts of “in-migration” (Zuwanderung) and ”integration” still stick to notions of the nation-state as being a ”container” embracing and controlling a population and a culture of its own, the various processes of material and imaginary mobility across the national borders contradict and challenge this notion as well as its political implications. By drawing on the transnational lifeworlds and the cultural productivity of migrants, anthropological research has made important contributions to render visible this challenge. It is argued, however, that an all too exclusive focus on migration may, in fact, rather conceal the wider effects of transnationalisation and cultural globalisation on the society and its cultural fabric as a whole.
Background The Deltaretrovirus genus comprises viruses that infect humans (HTLV), various simian species (STLV) and cattle (BLV). HTLV-I is the main causative agent in adult T-cell leukemia in endemic areas and some of the simian T-cell lymphotropic viruses have been implicated in the induction of malignant lymphomas in their hosts. BLV causes enzootic bovine leukosis in infected cattle or sheep. During the past few years several new Deltaretrovirus isolates have been described in various primate species. Two new HTLV-like viruses in humans have recently been identified and provisionally termed HTLV-III and HTLV-IV. In order to identify a broad spectrum of Deltaretroviruses by a single PCR approach we have established a novel consensus PCR based on nucleotide sequence data obtained from 42 complete virus isolates (HTLV-I/-II, STLV-I/-II/-III, BLV). The primer sequences were based on highly interspecies-conserved virus genome regions. We used this PCR to detect Deltaretroviruses in samples from adult patients with a variety of rare T-cell neoplasms in Germany. Results: The sensitivity of the consensus PCR was at least between 10-2 and 10-3 with 100% specificity as demonstrated by serial dilutions of cell lines infected with either HTLV-I, HTLV-II or BLV. Fifty acute T-cell lymphoblastic leukemia (T-ALL) samples and 33 samples from patients with various rare mature T-cell neoplasms (T-PLL, Sezary syndrome and other T-NHL) were subsequently investigated. There were no cases with HTLV-I, HTLV-II or any other Deltaretroviruses. Conclusions: The results rule out a significant involvement of HTLV-I or HTLV-II in these disease entities and show that other related Deltaretroviruses are not likely to be involved. The newly established Deltaretrovirus PCR may be a useful tool for identifying new Deltaretroviruses.
Background A procedure for including activity against enveloped viruses in the post-contamination treatment of hands has been recommended, but so far no European standard is available to implement it. In 2004, the German Robert Koch-Institute (RKI) and the German Association for the Control of Virus Disease (DVV) suggested that vaccinia virus and bovine viral diarrhea virus (BVDV) should be used as test viruses in a quantitative suspension test to determine the activity of a disinfectant against all enveloped viruses. Methods We have studied the activities of three commonly-used alcohol-based hand rubs (hand rub A, based on 45% propan-2-ol, 30% propan-1-ol and 0.2% mecetronium etilsulfate; hand rub B, based on 80% ethanol; hand rub C, based on 95% ethanol) against vaccinia virus and BVDV, and in addition against four other clinically relevant enveloped viruses: herpes simplex virus (HSV) types 1 and 2, and human and avian influenza A virus. The hand rubs were challenged with different organic loads at exposure time of 15, 30 and 60 s. According to the guidelines of both BGA/RKI and DVV, and EN 14476:2005, the reduction of infectivity of each test virus was measured on appropriate cell lines using a quantitative suspension test. Results All three alcohol-based hand rubs reduced the infectivity of vaccinia virus and BVDV by >= 4 log10-steps within 15 s, irrespective of the type of organic load. Similar reductions of infectivity were seen against the other four enveloped viruses within 15 s in the presence of different types of organic load. Conclusions Commonly used alcohol-based hand rubs with a total alcohol concentration >= 75% can be assumed to be active against clinically relevant enveloped viruses if they effectively reduce the infectivities of vaccinia virus and BVDV in a quantitative suspension test.
The properties of the outer crust of non-accreting cold neutron stars are studied by using modern nuclear data and theoretical mass tables updating in particular the classic work of Baym, Pethick and Sutherland. Experimental data from the atomic mass table from Audi, Wapstra, and Thibault of 2003 is used and a thorough comparison of many modern theoretical nuclear models, relativistic and non-relativistic ones, is performed for the first time. In addition, the influences of pairing and deformation are investigated. State-of-the-art theoretical nuclear mass tables are compared in order to check their differences concerning the neutron dripline, magic neutron numbers, the equation of state, and the sequence of neutron-rich nuclei up to the dripline in the outer crust of non-accreting cold neutron stars.
We study the phase diagram of dense, locally neutral three-flavor quark matter within the framework of the Nambu--Jona-Lasinio model. In the analysis, dynamically generated quark masses are taken into account self-consistently. The phase diagram in the plane of temperature and quark chemical potential is presented. The results for two qualitatively different regimes, intermediate and strong diquark coupling strength, are presented. It is shown that the role of gapless phases diminishes with increasing diquark coupling strength.
We study the effect of neutrino trapping on the phase diagram of dense, locally neutral three-flavor quark matter within the framework of a Nambu--Jona-Lasinio model. In the analysis, dynamically generated quark masses are taken into account self-consistently. The phase diagrams in the plane of temperature and quark chemical potential, as well as in the plane of temperature and lepton-number chemical potential are presented. We show that neutrino trapping favors two-flavor color superconductivity and disfavors the color-flavor-locked phase at intermediate densities of matter. At the same time, the location of the critical line separating the two-flavor color-superconducting phase and the normal phase of quark matter is little affected by the presence of neutrinos. The implications of these results for the evolution of protoneutron stars are briefly discussed. PACS numbers: 12.39.-x 12.38.Aw 26.60.+c
We discuss the phase diagram of moderately dense, locally neutral three-flavor quark matter using the framework of an effective model of quantum chromodynamics with a local interaction. The phase diagrams in the plane of temperature and quark chemical potential as well as in the plane of temperature and lepton-number chemical potential are discussed.
We study the phase diagram of dense, locally neutral three-flavor quark matter as a function of the strange quark mass, the quark chemical potential, and the temperature, employing a general nine-parameter ansatz for the gap matrix. At zero temperature and small values of the strange quark mass, the ground state of matter corresponds to the color-flavor-locked (CFL) phase. At some critical value of the strange quark mass, this is replaced by the recently proposed gapless CFL (gCFL) phase. We also find several other phases, for instance, a metallic CFL (mCFL) phase, a so-called uSC phase where all colors of up quarks are paired, as well as the standard two-flavor color-superconducting (2SC) phase and the gapless 2SC (g2SC) phase.
We discuss gapless colour superconductivity for neutral quark matter in β equilibrium at zero as well as at nonzero temperature. Basic properties of gapless superconductors are reviewed. The current progress and the remaining problems in the understanding of the phase diagram of strange quark matter are discussed.
We develop a utility based model of fluctuations, with nominal rigidities, and unemployment. In doing so, we combine two strands of research: the New Keynesian model with its focus on nominal rigidities, and the Diamond-Mortensen-Pissarides model, with its focus on labor market frictions and unemployment. In developing this model, we proceed in two steps. We first leave nominal rigidities aside. We show that, under a standard utility specification, productivity shocks have no effect on unemployment in the constrained efficient allocation. We then focus on the implications of alternative real wage setting mechanisms for fluctuations in unemployment. We then introduce nominal rigidities in the form of staggered price setting by firms. We derive the relation between inflation and unemployment and discuss how it is influenced by the presence of real wage rigidities. We show the nature of the tradeoff between inflation and unemployment stabilization, and we draw the implications for optimal monetary policy. JEL Classification: E32, E50
We focus on a quantitative assessment of rigid labor markets in an environment of stable monetary policy. We ask how wages and labor market shocks feed into the inflation process and derive monetary policy implications. Towards that aim, we structurally model matching frictions and rigid wages in line with an optimizing rationale in a New Keynesian closed economy DSGE model. We estimate the model using Bayesian techniques for German data from the late 1970s to present. Given the pre-euro heterogeneity in wage bargaining we take this as the first-best approximation at hand for modelling monetary policy in the presence of labor market frictions in the current European regime. In our framework, we find that labor market structure is of prime importance for the evolution of the business cycle, and for monetary policy in particular. Yet shocks originating in the labor market itself may contain only limited information for the conduct of stabilization policy. JEL Classification: E32, E52, J64, C11
Mortgage markets, collateral constraints, and monetary policy: do institutional factors matter?
(2006)
We study the role of institutional characteristics of mortgage markets in affecting the strength and timing of the effects of monetary policy shocks on house prices and consumption in a sample of OECD countries. We document three facts: (1) there is significant divergence in the structure of mortgage markets across the main industrialised countries; (2) at the business cycle frequency, the correlation between consumption and house prices increases with the degree of flexibility/development of mortgage markets; (3) the transmission of monetary policy shocks on consumption and house prices is stronger in countries with more flexible/developed mortgage markets. We then build a two-sector dynamic general equilibrium model with price stickiness and collateral constraints, where the ability of borrowing is endogenously linked to the nominal value of a durable asset (housing). We study how the response of consumption to monetary policy shocks is affected by alternative values of three key institutional parameters: (i) down-payment rate; (ii) mortgage repayment rate; (iii) interest rate mortgage structure (variable vs. fixed interest rate). In line with our empirical evidence, the sensitivity of consumption to monetary policy shocks increases with lower values of (i) and (ii), and is larger under a variable-rate mortgage structure. JEL Classification: E21, E44, E52
We study the problem of a policymaker who seeks to set policy optimally in an economy where the true economic structure is unobserved, and policymakers optimally learn from their observations of the economy. This is a classic problem of learning and control, variants of which have been studied in the past, but little with forward-looking variables which are a key component of modern policy-relevant models. As in most Bayesian learning problems, the optimal policy typically includes an experimentation component reflecting the endogeneity of information. We develop algorithms to solve numerically for the Bayesian optimal policy (BOP). However the BOP is only feasible in relatively small models, and thus we also consider a simpler specification we term adaptive optimal policy (AOP) which allows policymakers to update their beliefs but shortcuts the experimentation motive. In our setting, the AOP is significantly easier to compute, and in many cases provides a good approximation to the BOP. We provide a simple example to illustrate the role of learning and experimentation in an MJLQ framework. JEL Classification: E42, E52, E58
The paper considers optimal monetary stabilization policy in a forward-looking model, when the central bank recognizes that private-sector expectations need not be precisely model-consistent, and wishes to choose a policy that will be as good as possible in the case of any beliefs that are close enough to model-consistency. It is found that commitment continues to be important for optimal policy, that the optimal long-run inflation target is unaffected by the degree of potential distortion of beliefs, and that optimal policy is even more history-dependent than if rational expectations are assumed. JEL Classification: E52, E58, E42
I employ a large set of scanner price data collected in retail stores to document that (i) although the average magnitude of price changes is large, a substantial number of price changes are small in absolute value; (ii) the distribution of non-zero price changes has fat tails; and (iii) stores tend to adjust prices of goods in narrow product categories simultaneously. I extend the standard menu costs model to a multi-product setting in which firms face economies of scale in the technology of adjusting prices. The model, because of its ability to replicate this additional set of micro-economic facts, can generate aggregate fluctuations much larger than those in standard menu costs economies. JEL Classification: E31, E32
This paper uses factor-augmented vector autoregressions (FAVAR) estimated using a large data set to disentangle fluctuations in disaggregated consumer and producer prices which are due to macroeconomic factors from those due to sectorial conditions. This allows us to provide consistent estimates of the effects of US monetary policy on disaggregated prices. While sectorial prices respond quickly to sector-specific shocks, we find that for a large number of price series, there is a significant delay in the response of prices to monetary policy shocks. In addition, price responses display little evidence of a “price puzzle,” contrary to existing studies based on traditional VARs. The observed dispersion in the reaction of producer prices is relatively well explained by the degree of market power, as predicted by models with monopolistic competition. JEL Classification: E32, E52
Economists are beginning to investigate the causes and consequences of financial illiteracy to better understand why retirement planning is lacking and why so many households arrive close to retirement with little or no wealth. Our review reveals that many households are unfamiliar with even the most basic economic concepts needed to make saving and investment decisions. Such financial illiteracy is widespread: the young and older people in the United States and other countries appear woefully under-informed about basic financial concepts, with serious implications for saving, retirement planning, mortgages, and other decisions. In response, governments and several nonprofit organizations have undertaken initiatives to enhance financial literacy. The experience of other countries, including a saving campaign in Japan as well as the Swedish pension privatization program, offers insights into possible roles for financial literacy and saving programs. JEL Classification: D80, D91, G11
A number of authors have recently emphasized that the conventional model of unemployment dynamics due to Mortensen and Pissarides has difficulty accounting for the relatively volatile behavior of labor market activity over the business cycle. We address this issue by modifying the MP framework to allow for staggered multiperiod wage contracting. What emerges is a tractable relation for wage dynamics that is a natural generalization of the period-by-period Nash bargaining outcome in the conventional formulation. An interesting side-product is the emergence of spillover effects of average wages on the bargaining process. We then show that a reasonable calibration of the model can account well for the cyclical behavior of wages and labor market activity observed in the data. The spillover effects turn out to be important in this respect. JEL Classification: E32, E50, J64