232 research outputs found

    Investigations about migration of Festuco-Brometea and Koelerio-Corynephoretea species into fallow land

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    As a consequence of the structural changes in agriculture many fields were let rest in the past years and decades. This is a particular phenomenon in the New Laender. The present paper deals with fallow land on the "Kleiner Fallstein" in the northern foreland of the Harz (Saxony-Anhalt). The species migration patterns after five years rest is shown here by means of species lists, linear transects and a grid map. The question was which species are able to migrate into fallow land during five years and how far is the distance. The fallow land was chosen after the following criteria: areas directly above calcareous grassland, directly below calcareous grassland, and areas separated from calcareous grassland by broad shrubbery. Most prominent were Festuco-Brometea and Koelerio-Corynephoretea (Sedo-Scleranthetea) species as well as biennial species such as Echium vulgare and Cynoglossum officinale. Species with a high potential of dissemination such as Festuca rupicola migrated up to 204 meters, while Alyssum alyssoides and Bromus erectus were only found in the first 10 meters of the fallow land. 160 species were found in the fallow land but just one rare species (Asperula cynanchica). 21 Festuco-Brometea species und 15 Koelerio-Corynephoretea species migrated into fallow land. There is evidence that at least young fallow land may be a suitable habitat for these species. Many of the species are able to spread by stolones. The number of species migrated into the fallow land depends on the position of the fallow land relatively to the calcareous grassland. The highest number of Festuco-Brometea and Koelerio-Corynephoretea species migrated into fallow land below calcareous grassland, whereas less species migrated into fallow land above calcareous grassland. Broad shrubbery separating fallow land from calcareous grassland seems to delay the migration of Festuco-Brometea and Koelerio-Corynephoretea species into fallow land

    Sprouty2 enhances the tumorigenic potential of glioblastoma cells

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    Background: Sprouty2 (SPRY2), a feedback regulator of receptor tyrosine kinase (RTK) signaling, has been shown to be associated with drug resistance and cell proliferation in glioblastoma (GBM), but the underlying mechanisms are still poorly defined. Methods: SPRY2 expression and survival patterns of patients with gliomas were analyzed using publicly available databases. Effects of RNA interference targeting SPRY2 on cellular proliferation in established GBM or patient-derived GBM stemlike cells were examined. Loss- or gain-of-function of SPRY2 to regulate the tumorigenic capacity was assessed in both intracranial and subcutaneous xenografts. Results: SPRY2 was found to be upregulated in GBM, which correlated with reduced survival in GBM patients. SPRY2 knockdown significantly impaired proliferation of GBM cells but not of normal astrocytes. Silencing of SPRY2 increased epidermal growth factor-induced extracellular signal-regulated kinase (ERK) and Akt activation causing premature onset of DNA replication, increased DNA damage, and impaired proliferation, suggesting that SPRY2 suppresses DNA replication stress. Abrogating SPRY2 function strongly inhibited intracranial tumor growth and led to significantly prolonged survival of U87 xenograft-bearing mice. In contrast, SPRY2 overexpression promoted tumor propagation of low-tumorigenic U251 cells. Conclusions: The present study highlights an antitumoral effect of SPRY2 inhibition that is based on excessive activation of ERK signaling and DNA damage response, resulting in reduced cell proliferation and increased cytotoxicity, proposing SPRY2 as a promising pharmacological target in GBM patients

    It's the Motivation Stupid!

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    This paper attempts to explain the success of secondary currencies. Success is defined as the degree to which the initiators of these currencies manage to reach their original goals. In order to do so, we draw on two explanatory factors: the motivation of a currency’s founder and the degree of organization. We employed a combination of qualitative interviews, secondary literature review and standardized questionnaires with seven secondary currency projects in Croatia (CROM), Germany (KannWas, Engelgeld), Greece (Ovolos, TEM) and the United Kingdom (Bristol Pound, Brixton Pound). The main findings are that projects which pursue several different motivations are more successful than those with fewer goals. As for the degree of organization, projects which score high on all dimensions of organization are correlated with higher project success. Building on this we propose a typology of two groups: Type 1 cases have low diversity of motivation and organization (CROM and Engelgeld) and Type 2 cases have high diversity of motivation and organization (Bristol Pound, Brixton Pound, and TEM). The two remaining cases, the Ovolos and the KannWas cannot be clearly assigned to any of the types. The "motivation-organization typology" can guide future research on the motivation of founding and using secondary currencies

    Outcome after Desensitization in HLA or ABO-Incompatible Kidney Transplant Recipients: A Single Center Experience

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    Background The shortage of deceased donors led to an increase of living donor kidney (LDK) transplantations performed in the presence of donor-specific antibodies (DSA) or ABO incompatibility (ABOi) using various desensitization protocols. Methods We herein analyzed 26 ABOi and 8 Luminex positive DSA patients who were successfully desensitized by anti-CD20, antigen-specific immunoadsorption and/or plasmapheresis to receive an LDK transplant. Twenty LDK recipients with non-donor-specific HLA-antibodies (low risk) and 32 without anti-HLA antibodies (no risk) served as control groups. Results 1-year graft survival rate and renal function was similar in all 4 groups (creatinine: 1.63 +/- 0.5 vs 1.78 +/- 0.6 vs 1.64 +/- 0.5 vs 1.6 +/- 0.3 mg/dl in ABOi, DSA, low risk and no risk group). The incidence of acute T-cell mediated rejections did not differ between the 4 groups (15% vs 12, 5% vs 15% vs 22% in ABOi, DSA, low risk and no risk), while antibody-mediated rejections were only found in the DSA (25%) and ABOi (7.5%) groups. Incidence of BK nephropathy (BKVN) was significantly more frequent after desensitization as compared to controls (5/34 vs 0/52, p = 0.03). Conclusion We demonstrate favorable short-term allograft outcome in LDK transplant recipients after desensitization. However, the desensitization was associated with an increased risk of BKVN

    Holocene climate and environmental change in north-eastern Kamchatka (Russian Far East), inferred from a multi-proxy study of lake sediments

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    The study was supported by the Swedish Research Council through grants 621-2004-5224 and 621-2005-4444 to K.D. Bennett. A. Self and N. Solovieva acknowledge S. Brooks and V. Jones and were supported by NERC grant NE/H008160/1.A sediment record from a small lake in the north-eastern part of the Kamchatka Peninsula has been investigated in a multi-proxy study to gain knowledge of Holocene climatic and environmental change. Pollen, diatoms, chironomids and selected geochemical parameters were analysed and the sediment record was dated with radiocarbon. The study shows Holocene changes in the terrestrial vegetation as well as responses of the lake ecosystem to catchment maturity and multiple stressors, such as climate change and volcanic eruptions. Climate change is the major driving force resulting in the recorded environmental changes in the lake, although recurrent tephra deposition events also contributed. The sediment record has an age at the base of about 10,000 cal yrs BP, and during the first 400 years the climate was cold and the lake exhibited extensive ice-cover during winter and relatively low primary production. Soils in the catchment were poor with shrub alder and birches dominating the vegetation surrounding the lake. At about 9600–8900 cal yrs BP the climate was cold and moist, and strong seasonal wind stress resulted in reduced ice-cover and increased primary production. After ca. 8900 cal yrs BP the forest density increased around the lake, runoff decreased in a generally drier climate resulting in decreased primary production in the lake until ca. 7000 cal yrs BP. This generally dry climate was interrupted by a brief climatic perturbation, possibly attributed to the 8.2 ka event, indicating increasingly windy conditions with thick snow cover, reduced ice-cover and slightly elevated primary production in the lake. The diatom record shows maximum thermal stratification at ca. 6300–5800 cal yrs BP and indicates together with the geochemical proxies a dry and slightly warmer climate resulting in a high productive lake. The most remarkably change in the catchment vegetation occurred at ca. 4200 cal yrs BP in the form of a conspicuous increase in Siberian dwarf pine (Pinus pumila), indicating a shift to a cooler climate with a thicker and more long-lasting snow cover. This vegetational change was accompanied by marked shifts in the diatom and chironomid stratigraphies, which are also indicative of colder climate and more extensive ice-cover.Publisher PDFPeer reviewe
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