Refine
Year of publication
- 2005 (562) (remove)
Document Type
- Article (215)
- Working Paper (79)
- Doctoral Thesis (58)
- Part of a Book (51)
- Preprint (43)
- Part of Periodical (40)
- Conference Proceeding (36)
- Report (22)
- Book (11)
- Review (3)
Language
- English (562) (remove)
Has Fulltext
- yes (562) (remove)
Keywords
- Artikulation (13)
- Phonetik (13)
- Artikulatorische Phonetik (12)
- Englisch (11)
- Artikulator (8)
- Deutsch (7)
- Europäische Union (7)
- Geldpolitik (7)
- Bedeutungswandel (6)
- Computerlinguistik (6)
Institute
- Physik (72)
- Center for Financial Studies (CFS) (42)
- Wirtschaftswissenschaften (39)
- Biochemie und Chemie (32)
- Medizin (24)
- Frankfurt Institute for Advanced Studies (FIAS) (20)
- Geowissenschaften (17)
- E-Finance Lab e.V. (16)
- Extern (15)
- Biowissenschaften (14)
During the last 15 years most central and east european countries faced an era of institutional, economic and demographic transition. With the fall of the wall and the end of the Soviet Union, the former socialist countries transformed their political, economic and social institutions; today, some of them are already a member state of the European Union. The re- unificated Germany was not only affected by this process in its eastern part, the former German Democratic Republic (GDR), where the political and institutional structures were entirely exchanged; with the end of the “Rheinische Bundesrepublik”, the incarnation of a welfare and growth oriented Fordist society, also former West Germany had to adapt to this transition and still is facing a process of institutional modernisation.
Mechanical stress is known to modulate fundamental events such as cell life and death. Mechanical stretch in particular has been identified as a positive regulator of proliferation in skin keratinocytes and other cell systems. In the present study it was investigated whether antiapoptotic signaling is also stimulated by mechanical stretch. It was demonstrated that mechanical stretch rapidly induced the phosphorylation of the proto-oncogene protein kinase B (PKB)/Akt at both phosphorylation sites (serine 473/threonine 308) in different epithelial cells (HaCaT, A-431, and human embryonic kidney-293). Blocking of phosphoinositide 3-OH kinase by selective inhibitors (LY-294002 and wortmannin) abrogated the stretch-induced PKB/Akt phosphorylation. Furthermore mechanical stretch stimulated phosphorylation of epidermal growth factor receptor (EGFR) and the formation of EGFR membrane clusters. Functional blocking of EGFR phosphorylation by either selective inhibitors (AG1478 and PD168393) or dominant-negative expression suppressed stretch-induced PKB/Akt phosphorylation. Finally, the angiotensin II type 1 receptor (AT1-R) was shown to induce positive transactivation of EGFR in response to cell stretch. These findings define a novel signaling pathway of mechanical stretch, namely the activation of PKB/Akt by transactivation of EGFR via angiotensin II type 1 receptor. Evidence is provided that stretch-induced activation of PKB/Akt protects cells against induced apoptosis.
Soluble guanylyl cyclase (sGC) is the major cytosolic receptor for nitric oxide (NO) that converts GTP into the second messenger cGMP in a NO-dependent manner. Other factors controlling this key enzyme are intracellular proteins such as Hsp90 and PSD95, which bind to sGC and modulate its activity, stability, and localization. To date little is known about the effects of posttranslational modifications of sGC, although circumstantial evidence suggests that reversible phosphorylation may contribute to sGC regulation. Here we demonstrate that inhibitors of protein-tyrosine phosphatases such as pervanadate and bisperoxo(1,10-phenanthroline)oxovanadate(V) as well as reactive oxygen species such as H2O2 induce specific tyrosine phosphorylation of the β1 but not of the α1 subunit of sGC. Tyrosine phosphorylation of sGCβ1 is also inducible by pervanadate and H2O2 in intact PC12 cells, rat aortic smooth muscle cells, and in rat aortic tissues, indicating that tyrosine phosphorylation of sGC may also occur in vivo. We have mapped the major tyrosine phosphorylation site to position 192 of β1, where it forms part of a highly acidic phospho-acceptor site for Src-like kinases. In the phosphorylated state Tyr(P)-192 exposes a docking site for SH2 domains and efficiently recruits Src and Fyn to sGCβ1, thereby promoting multiple phosphorylation of the enzyme. Our results demonstrate that sGC is subject to tyrosine phosphorylation and interaction with Src-like kinases, revealing an unexpected cross-talk between the NO/cGMP and tyrosine kinase signaling pathways at the level of sGC.
Cathepsin D (CatD) is a lysosomal aspartic proteinase and plays an important role in the degradation of proteins and in apoptotic processes induced by oxidative stress, cytokines, and aging. All of these stimuli are potent inducers of endothelial cell apoptosis. Therefore, we investigated the role of CatD in endothelial cell apoptosis and determined the underlying mechanisms. Incubation with 100-500 microm H2O2 for 12 h induced apoptosis in endothelial cells. To determine a role for CatD, we co-incubated endothelial cells with the CatD inhibitor pepstatin A. Pepstatin A as well as genetic knock down of CatD abolished H2O2-induced apoptosis. In contrast, overexpression of CatD wild type but not a catalytically inactive mutant of CatD (CatDD295N) induced apoptosis under basal conditions. To gain insights into the underlying mechanisms, we investigated the effect of CatD on reactive oxygen species (ROS) formation. Indeed, knocking down CatD expression reduced H2O2-induced ROS formation and apoptosis. The major redox regulator in endothelial cells is thioredoxin-1 (Trx), which plays a crucial role in apoptosis inhibition. Thus, we hypothesized that CatD may alter Trx protein levels and thereby promote formation of ROS and apoptosis. Incubation with 100 microm H2O2 for 6 h decreased Trx protein levels, whereas Trx mRNA was not altered. H2O2-induced Trx degradation was inhibited by pepstatin A and genetic knock down of CatD but not by other protease inhibitors. Incubation of unstimulated cell lysates with recombinant CatD significantly reduced Trx protein levels in vitro, which was completely blocked by pepstatin A pre-incubation. Overexpression of CatD reduced Trx protein in cells. Moreover, H2O2 incubation led to a translocation of Trx to the lysosomes prior to the induction of apoptosis. Taken together, CatD induces apoptosis via degradation of Trx protein, which is an essential anti-apoptotic and reactive oxygen species scavenging protein in endothelial cells.
Human endothelial circulating progenitor cells (CPCs) can differentiate to cardiomyogenic cells during co-culture with neonatal rat cardiomyocytes. Wnt proteins induce myogenic specification and cardiac myogenesis. Here, we elucidated the effect of Wnts on differentiation of CPCs to cardiomyogenic cells. CPCs from peripheral blood mononuclear cells were isolated from healthy volunteers and co-cultured with neonatal rat cardiomyocytes. 6–10 days after co-culture, cardiac differentiation was determined by α-sarcomeric actinin staining of human lymphocyte antigen-positive cells (fluorescence-activated cell-sorting analysis) and mRNA expression of human myosin heavy chain and atrial natriuretic peptide. Supplementation of co-cultures with Wnt11-conditioned medium significantly enhanced the differentiation of CPCs to cardiomyocytes (1.7 ± 0.3-fold), whereas Wnt3A-conditioned medium showed no effect. Cell fusion was not affected by Wnt11-conditioned medium. Because Wnts inhibit glycogen synthase kinase-3β, we further determined whether the glycogen synthase kinase-3β inhibitor LiCl also enhanced cardiac differentiation of CPCs. However, LiCl (10 mm) did not affect CPC differentiation. In contrast, Wnt11-conditioned medium time-dependently activated protein kinase C (PKC). Moreover, the PKC inhibitors bisindolylmaleimide I and III significantly blocked differentiation of CPCs to cardiomyocytes. PKC activation by phorbol 12-myristate 13-acetate significantly increased CPC differentiation to a similar extent as compared with Wnt11-conditioned medium. Our data demonstrate that Wnt11, but not Wnt3A, augments cardiomyogenic differentiation of human CPCs. Wnt11 promotes cardiac differentiation via the non-canonical PKC-dependent signaling pathway.
Within the ADD-model, we elaborate an idea by Vacavant and Hinchliffe [J. Phys. G 27 (2001) 1839] and show quantitatively how to determine the fundamental scale of TeV-gravity and the number of compactified extra dimensions from data at LHC. We demonstrate that the ADD-model leads to strong correlations between the missing ET in gravitons at different center of mass energies. This correlation puts strong constraints on this model for extra dimensions, if probed at s=5.5 TeV and s=14 TeV at LHC.
The kaon nuclear optical potential is studied including the effect of the Θ+ pentaquark. The one-nucleon contribution is obtained using an extension of the Jülich meson-exchange potential as bare kaon–nucleon interaction. Significant differences between a fully self-consistent calculation and the usually employed low-density Tρ approach are observed. The influence of the one-nucleon absorption process, KN→Θ+, on the kaon optical potential is negligible due to the small width of the pentaquark. In contrast, the two-nucleon mechanism, KNN→Θ+N, estimated from the coupling of the pentaquark to a two-meson cloud, provides the required amount of additional kaon absorption to reconcile with data the systematically low K+-nucleus reaction cross sections found by the theoretical models.
We solve the coupled Wong Yang–Mills equations for both U(1) and SU(2) gauge groups and anisotropic particle momentum distributions numerically on a lattice. For weak fields with initial energy density much smaller than that of the particles we confirm the existence of plasma instabilities and of exponential growth of the fields which has been discussed previously. Also, the SU(2) case is qualitatively similar to U(1), and we do find significant “abelianization” of the non-Abelian fields during the period of exponential growth. However, the effect nearly disappears when the fields are strong. This is because of the very rapid isotropization of the particle momenta by deflection in a strong field on time scales comparable to that for the development of Yang–Mills instabilities. This mechanism for isotropization may lead to smaller entropy increase than collisions and multiplication of hard gluons, which is interesting for the phenomenology of high-energy heavy-ion collisions.
Large extra dimensions could lower the Planck scale to experimentally accessible values. Not only is the Planck scale the energy scale at which effects of modified gravity become important. The Planck length also acts as a minimal length in nature, providing a natural ultraviolet cutoff and a limit to the possible resolution of spacetime.
In this Letter we examine the influence of the minimal length on the Casimir energy between two plates.
Alternative NADH dehydrogenases (NADH:ubiquinone oxidoreductases) are single subunit respiratory chain enzymes found in plant and fungal mitochondria and in many bacteria. It is unclear how these peripheral membrane proteins interact with their hydrophobic substrate ubiquinone. Known inhibitors of alternative NADH dehydrogenases bind with rather low affinities. We have identified 1-hydroxy-2-dodecyl-4(1H)quinolone as a high affinity inhibitor of alternative NADH dehydrogenase from Yarrowia lipolytica. Using this compound, we have analyzed the bisubstrate and inhibition kinetics for NADH and decylubiquinone. We found that the kinetics of alternative NADH dehydrogenase follow a ping-pong mechanism. This suggests that NADH and the ubiquinone headgroup interact with the same binding pocket in an alternating fashion.
Generation of reactive oxygen species (ROS) is increasingly recognized as an important cellular process involved in numerous physiological and pathophysiological processes. Complex I (NADH:ubiquinone oxidoreductase) is considered as one of the major sources of ROS within mitochondria. Yet, the exact site and mechanism of superoxide production by this large membrane-bound multiprotein complex has remained controversial. Here we show that isolated complex I from Yarrowia lipolytica forms superoxide at a rate of 0.15% of the rate measured for catalytic turnover. Superoxide production is not inhibited by ubiquinone analogous inhibitors. Because mutant complex I lacking a detectable iron-sulfur cluster N2 exhibited the same rate of ROS production, this terminal redox center could be excluded as a source of electrons. From the effect of different ubiquinone derivatives and pH on this side reaction of complex I we concluded that oxygen accepts electrons from FMNH or FMN semiquinone either directly or via more hydrophilic ubiquinone derivatives.
The transporter associated with antigen processing (TAP)-like (TAPL, ABCB9) belongs to the ATP-binding cassette transporter family, which translocates a vast variety of solutes across membranes. The function of this half-size transporter has not yet been determined. Here, we show that TAPL forms a homodimeric complex, which translocates peptides across the membrane. Peptide transport strictly requires ATP hydrolysis. The transport follows Michaelis-Menten kinetics with low affinity and high capacity. Different nucleotides bind and energize the transport with a slight predilection for purine bases. The peptide specificity is very broad, ranging from 6-mer up to at least 59-mer peptides with a preference for 23-mers. Peptides are recognized via their backbone, including the free N and C termini as well as side chain interactions. Although related to TAP, TAPL is unique as far as its interaction partners, transport properties, and substrate specificities are concerned, thus excluding that TAPL is part of the peptide-loading complex in the classic route of antigen processing via major histocompatibility complex class I molecules.
IAD annual report 2004/05
(2005)
What is the objective or purpose of business Management? According to the dominant theory of contemporary financial management scholarship, agency theory, business managers are obligated to maximise owner or shareholder value. According to most theories of business ethics, however, some owner-value-maximising actions should not be performed, because they would be unethical. Because business management scholars and business ethics scholars have not resolved this contradiction, students of commerce receive a contradictory education. The twenty-five essays in this interdisciplinary, international volume address the question of the objective or purpose of business management from a wide range of theoretical perspectives. Since some of the writers contradict one another, it is not possible that all of them are correct. Nevertheless, the fact that many of them argue persuasively that business managers should aspire to more than maximisation of a financial variable challenges everyone with a theoretical or practical interest in commerce to reconsider acceptance of the owner-value paradigm and to develop a richer conception of the profession of business management.
This book brings together multiple voices and positions from Africa. These voices, assembled during a 2003 Soap Summit held in Nairobi, are powerful and varied and suggest ways in which issues of health could be tackled in an entertaining manner. The summit organised by Population Communications International - Africa. highlighted the critical role that the arts can play in ensuring better health, especially among the youth. It resulted from the recognition that young people in Africa are faced with a myriad of problems and complications as they struggle to deal with growth and identity formation, within a globalising social and economic setup. They are in dire need of information on their own sexuality and how to deal with it and are getting conflicting signals from the mass media, as well as their immediate environment. The youth are under intense pressure from their peers to engage in premarital sex, which is in most cases unprotected. The HIV/AIDS epidemic presents frightening challenges and all health programs should look for ways of dealing with it. Of great to concern is the vulnerability of women and girls in Africa due to rising poverty, gender violence, lack of access to youth-friendly reproductive health facilities, and lack of a conducive infrastructure especially in informal settlements and in the rural areas. The myriad problems presented by the pandemic require a multi-sectoral approach. This book brings together a number of strategies being undertaken in Africa that combine entertainment and education in a positive way. The voices from the Soap Summit are interspersed with those of the Editor to create a dialogue on entertainment-education that contributes to the discussion on the way social change might be undertaken.
Chairman of Fools
(2005)
Chairman of Fools explores the plight of Farai Chari, a supposedly successful writer, professor and self-acclaimed artist, living in an African culture in which tradition weighs heavy and middle class aspirations are crude. Farai yearns for a world in which men and women can freely associate with one another and gratify their passions without moral chastisement.
The sequel to the award-winning Writing Still, this new collection of stories paints an engaging - and sometimes challenging - picture of contemporary life and concerns in Zimbabwe. Like its predecessor, Writing Now combines well-established writers - Chinodya, Mupfudzi, Eppel, Chingono - with several new voices. Although the stories emerge from lives of economic hardship and privation, their tone is by no means uniformly. Zimbabwean writers continue to demonstrate that sharp humour and surreal fantasy can grow from the bleakest of roots.
Zimbabwe's Cultural Heritage
(2005)
' Zimbabwe's Cultural Heritage won first prize in the Zimbabwe Book Publishers Association Awards in 2006 for Non-fiction: Humanities and Social Sciences. It is a collection of pieces of the culture of the Ndebele, Shona, Tonga, Kalanga, Nambiya, Xhosa and Venda. The book gives the reader an insight into the world view of different peoples, through descriptions of their history and life events such as pregnancy, marriage and death. ''...the most enduring book ever on Zimbabwean history. This book will help people change their attitude towards each other in Zimbabwe.'' - Zimbabwe Book Publishers Association Awards citation'
Short Writings from Bulawayo won the Literature in English category at the 2005 Zimbabwe Book Publishers Association awards. It is a book of stories, poems and non-fiction pieces that are evocative of Zimbabwe's second city and its rural surroundings. The collection from 23 contributors tells of many things: of family and friendship, or fear and death, or witches and spirits, of hunger and drought, of dreams and aspirations, of leaving home and leaving Zimbabwe, of queues and loneliness, of football and bicycles and of growing old and of love. A unifying theme of many of the stories and poems is loss - of innocence, of purpose, of love, of culture, of belonging, and of life.
Elderly people still play a minor role in research on information needs and usage patterns of Internet users. Online research and advocacy groups look optimistically at the (economic and social) potential of the active and technology–skilled elderly; other approaches dealing with the social appropriation of technology see obstacles and stress the dangers of an increasing digital divide between generations. Our objective is to refer to taken for granted normative assumptions of the digital divide discourse, highlighting different requirements for the appropriation of the Internet. Using the concept of technological generations we look at formal and informal learning of young and elderly people in the German context. We use survey material and field impressions we gained in various technology related studies. The results show that the "two worlds apart" assumption (young vs. elderly people) is too simplistic. Factors like gender, education and socio–economic status still play an important role for acceptance and diffusion of a technology. The diffusion rate among the elderly is increasing, but will continue to lag behind the figures of the young users. Cultural preparations and easy access modes are essential for the elderly, who could make use of latecomer advantages. Informal learning and peer group support will be crucial for the diffusion of the Internet among the elderly. In our conclusions we look at the specific social status of the elderly cohort, which makes a comparison with other social groups very difficult.
IN A CASE STUDY IN THE GERMAN RETAIL BANKING BUSINESS IT IS SHOWN THAT ALIGNMENT BETWEEN IT AND BUSINESS UNIT IS CRUCIAL FOR THE ACTUAL USAGE OF IT SYSTEMS WHICH IN TURN IS A KEY DRIVER FOR BUSINESS PROCESS QUALITY. BANKS SHOULD THEREFORE FOSTER INTERRELATIONSHIPS BETWEEN IT AND BUSINESS AS WELL AS CROSS FUNCTIONAL WORK BIOGRAPHIES OF TEAM LEADERS
INDUSTRIALIZATION TENDENCIES WITHIN THE CREDIT BUSINESS ARE IN PARTS BROADER SOPHISTICATED THAN WITHIN FINANCIAL PROCESSES OF OTHER INDUSTRIES. CREDIT PROCESS MANAGERS OF BANKS ESTIMATE ECONOMIES OF SCALE AND SKILL ACHIEVABLE BY OUTSOURCING TO BE HIGHER THAN CHIEF FINANCIAL OFFICERS OF NON-BANKS DO. FURTHERMORE, ECONOMIES OF SCOPE, WHICH INHIBIT SELECTIVE SOURCING, ARE EVALUATED AS LESS PROBLEMATIC.
Colorectal carcinoma (CRC) is a major cause of morbidity and mortality in Western countries. It has so far been molecularly defined mainly by alterations of the Wnt pathway. We show here for the first time that aberrant activities of the signal transducer and activator of transcription STAT3 actively contribute to this malignancy and, thus, are a potential therapeutic target for CRC. Constitutive STAT3 activity was found to be abundant in dedifferentiated cancer cells and infiltrating lymphocytes of CRC samples, but not in non-neoplastic colon epithelium. Cell lines derived from malignant colorectal tumors lost persistent STAT3 activity in culture. However, implantation of colon carcinoma cells into nude mice resulted in restoration of STAT3 activity, suggesting a role of an extracellular stimulus within the tumor microenvironment as a trigger for STAT activation. STAT3 activity in CRC cells triggered through interleukin-6 or through a constitutively active STAT3 mutant promoted cancer cell multiplication, whereas STAT3 inhibition through a dominant-negative variant impaired IL-6-driven proliferation. Blockade of STAT3 activation in CRCderived xenograft tumors slowed down their development, arguing for a contribution of STAT3 to colorectal tumor growth.
I propose that the rising number of dualearner couples in the United States impacts the trend toward declining residential mobility and rising commute times. I describe these mobility trends in the United States, first relocation trends and then daily commuting trends. My research views the commute as the bridge in time and space between home and work that a) reflects couples' negotiation of preferences, relative job importance, barriers, and opportunities; b) has consequences for family functioning, c) reflects gender differences in the ways time and place are organized, and d) varies across the life course, by race, class, and region. I describe differences in family type and family functioning based on the commuting pattern and suggest a course of future comparative research that may improve awareness of how families and couples handle labor market demands, what structures shape the picture of couples mobility, and how nation-specific circumstances orient couples toward certain kinds of mobility and away from others.