542 research outputs found
Carl Einsteins Entwurf der Moderne:Von der kubistischen Raumanschauung zum mythischen Realismus Georges Braques
Carl Einstein (1885-1940) wurde als Kunsttheoretiker und -kritiker durch seine Schrift "Negerplastik" (1915) und die ab 1926 in mehreren Auflagen
erschienene Propyläen Kunstgeschichte "Die Kunst des 20. Jahrhunderts" bekannt.
Die vorliegende Arbeit untersucht Carl Einsteins Auseinandersetzung mit dem Werk von Georges Braque, welche die Grundlage seiner Kunsttheorie bildet. Die kritischen Analysen von Einsteins Konzept der kubistischen Raumanschauung, das er zuerst in "Die Kunst des 20. Jahrhunderts" darstellt, sowie seiner
Entwicklung einer Theorie des "mythischen Realismus", die er im Buch "Georges Braque" formuliert, bilden die Hauptteile dieser Studie. Letzteres wird in
dieser Ausführlichkeit erstmalig zum Gegenstand der wissenschaftlichen Untersuchung. Dabei wird deutlich, dass Einsteins Texte auf einer theoretischen
und zugleich sprachlich-literarischen Ebene die Polyvalenz in der Kunst der Moderne als eine ihr eigene Qualität verständlich machen. <br/
Fermi Surface and Quasiparticle Excitations of overdoped Tl2Ba2CuO6+d by ARPES
The electronic structure of the high-T_c superconductor Tl2Ba2CuO6+d is
studied by ARPES. For a very overdoped Tc=30K sample, the Fermi surface
consists of a single large hole pocket centered at (pi,pi) and is approaching a
topological transition. Although a superconducting gap with d_x^2-y^2 symmetry
is tentatively identified, the quasiparticle evolution with momentum and
binding energy exhibits a marked departure from the behavior observed in under
and optimally doped cuprates. The relevance of these findings to scattering,
many-body, and quantum-critical phenomena is discussed.Comment: Revised manuscript, in press on PRL. A high-resolution version can be
found at
http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/Tl2201_LE.pdf
and related material at
http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/articles.htm
SHORT COMMUNICATION: Complementary tumor induction in neural grafts exposed to N-ethyl-N-nitrosourea and an activated myc gene
Using a combination of transplacental carcinogen exposure and retrovirus-mediated oncogene transfer into fetal brain transplants, we have studied complementary transformation by N-ethyl-N-nitrosourea (NEU) and the v-myc oncogene in the nervous system. Previous experiments had demonstrated that both agents will not induce tumors independently whereas simultaneous expression of v-H-ras and v-gag/myc exerted a powerful transforming potential in neural grafts. In order to identify other genetic alterations that co-operate with an activated myc gene, the neurotropic carcinogen NEU was used to generate mutations of cellular genes. On embryonic day 14 (ED14), pregnant donor animals (F344 rats) received a single i.v. dose of NEU (50 mg/kg). Twenty-four hours later (ED15), the fetal brains were removed, triturated and incubated with a retroviral vector carrying the v-gag/myc oncogene. Subsequently, these primary cell suspensions were transplanted stereotactically into the caudate-putamen of syngenic adult recipients. After latency periods of 3-6 months, 5 of 10 recipients harboring ED15 fetal brain transplants developed malignant, poorly differentiated neuroectodermal tumors in the grafts. No tumor development was observed in seven recipients harboring ED16 neural grafts. Cell lines were established from three tumors and the 110 kd gag/myc fusion protein encoded by the retroviral construct was identified in the tumors by Western blotting. Several candidate genes for mutational activation by NEU including the H-ras, K-ras and neu oncogenes were analyzed for specific point mutations by polymerase chain reaction (PCR) and direct DNA sequencing of the PCR products. However, no mutations were found in any of these genes. These findings lend further support to the multistep hypothesis of neoplastic transformation in the brain. The tumors induced in this model provide an interesting tool for the identification of genes that co-operate with an activated myc gene in neurocarcinogenesi
Kinetic oxygen measurements by CVC96 in L-929 cell cultures
Generally animal and human cells use oxygen during their whole life. Consequently the oxygen use is a simple indicator to test the vitality of cells. When the vitality decreases by the delivery of toxic substances the decrease can be observed directly by the oxygen-use of the cells. To get fast information of the vitality of cells we have measured the O(2)-tension by testing a new model of a bioreactor, the Cell Vitality Checker 96 (CVC96), in practical application. With this CVC96, soon a simple test will exist for the measurement of the oxygen use. In this respect the question had to be answered whether the use in the laboratory is easy and whether oxygen as a parameter in the vitality test can also be applied in future for problems in the field of material testing
Efficacy and Drug Survival after Switching from Etanercept to the Biosimilar SB4: A Real-Life Long-Term Study
We evaluated the 3-year drug survival and efficacy of the biosimilar SB4/Benepali in rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS) patients, pre-viously treated with etanercept (ETA). Drug survival rate was calculated using the Kaplan\u2013Meier method and Cox proportional hazard models were developed to examine predictors of SB4 discontin-uation. 236 patients (120 RA, 80 PsA and 36 AS), aged 60.7 \ub1 13.8 years and with an ETA duration of 4.1 \ub1 3.4 years were included. The 3-year retention rate for SB4 was 94.4%, 88% and 86% in AS, RA and PsA patients, respectively, with no difference between groups. Patients without comorbid disease had higher retention rates vs. patients with comorbid disease (90% vs. 60%, p < 0.0001). Disease activity, as measured by DAS28, DAPSA and BASDAI remained stable over the 3 years. Comorbid disease (hazard ratio; HR: 4.06, p < 0.0001) and HAQ at baseline (HR: 2.42, p = 0.0024) significantly increased the risk of SB4 discontinuation, while previous ETA duration was negatively associated with SB4 discontinuation (HR: 0.97, p = 0.0064). Forty-one (17.4%) patients left the study due to the interruption of the SB4 treatment, 31 (75.6%) discontinued due to inefficacy and 10 (24.4%) due to adverse events. This real-life study confirms the similar efficacy profile of ETA with long-term retention and a good safety profile in inflammatory arthritis patients
Role of the VEGF ligand to receptor ratio in the progression of mismatch repair-proficient colorectal cancer
The VEGF family of ligands and receptors are intimately involved in tumor angiogenesis, lymphangiogenesis and metastasis. The evaluation of VEGF ligand/receptor ratios may provide a more profound understanding of the involvement of these proteins in colorectal tumour progression. The aim of this study was to elucidate the role of the VEGF ligand/receptor ratios on tumour progression and metastasis in patients with mismatch repair-proficient colorectal cancer
Endothelial CD276 (B7-H3) expression is increased in human malignancies and distinguishes between normal and tumour-derived circulating endothelial cells
Background:Mature circulating endothelial cells (CEC) are surrogate markers of endothelial damage. CEC measured in patients with advanced cancer are thought not only to derive from damaged normal vasculature (n-CEC), bu
Embryonic stem cells in scaffold-free three-dimensional cell culture: osteogenic differentiation and bone generation
Extracorporeal formation of mineralized bone-like tissue is still an unsolved challenge in tissue engineering. Embryonic stem cells may open up new therapeutic options for the future and should be an interesting model for the analysis of fetal organogenesis. Here we describe a technique for culturing embryonic stem cells (ESCs) in the absence of artificial scaffolds which generated mineralized miromasses. Embryonic stem cells were harvested and osteogenic differentiation was stimulated by the addition of dexamethasone, ascorbic acid, and ß-glycerolphosphate (DAG). After three days of cultivation microspheres were formed. These spherical three-dimensional cell units showed a peripheral zone consisting of densely packed cell layers surrounded by minerals that were embedded in the extracellular matrix. Alizarine red staining confirmed evidence of mineralization after 10 days of DAG stimulation in the stimulated but not in the control group. Transmission electron microscopy demonstrated scorching crystallites and collagenous fibrils as early indication of bone formation. These extracellular structures resembled hydroxyl apatite-like crystals as demonstrated by distinct diffraction patterns using electron diffraction analysis. The micromass culture technique is an appropriate model to form three-dimensional bone-like micro-units without the need for an underlying scaffold. Further studies will have to show whether the technique is applicable also to pluripotent stem cells of different origin
DNA methylation-based prediction of response to immune checkpoint inhibition in metastatic melanoma
Background Therapies based on targeting immune checkpoints have revolutionized the treatment of metastatic melanoma in recent years. Still, biomarkers predicting long-term therapy responses are lacking.
Methods A novel approach of reference-free deconvolution of large-scale DNA methylation data enabled us to develop a machine learning classifier based on CpG sites, specific for latent methylation components (LMC), that allowed for patient allocation to prognostic clusters. DNA methylation data were processed using reference-free analyses (MeDeCom) and reference-based computational tumor deconvolution (MethylCIBERSORT, LUMP).
Results We provide evidence that DNA methylation signatures of tumor tissue from cutaneous metastases are predictive for therapy response to immune checkpoint inhibition in patients with stage IV metastatic melanoma.
Conclusions These results demonstrate that LMC-based segregation of large-scale DNA methylation data is a promising tool for classifier development and treatment response estimation in cancer patients under targeted immunotherapy
Seroprevalence of transfusion-transmissible infections and evaluation of the pre-donation screening performance at the Provincial Hospital of Tete, Mozambique
<p>Abstract</p> <p>Background</p> <p>The World Health Organization recommends universal and quality-controlled screening of blood donations for the major transfusion-transmissible infections (TTIs): human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis. The study objectives were to determine the seroprevalence of these TTIs among blood donors at the Provincial Hospital of Tete, Mozambique, and to assess the local pre-donation screening performance.</p> <p>Methods</p> <p>All consenting voluntary and replacement candidate blood donors were consecutively included from February to May 2009. Sera of all candidates, independent of deferral by questionnaire, were submitted to screening with quality-assured rapid or simple assays for HIV, HBV surface antigen (HBsAg), HCV and syphilis. Assays locally used by the blood bank for HBV and syphilis screening were run in parallel to quality-assured external assays supplied during the study, and all discordant samples were submitted to confirmation testing in reference laboratories in Mozambique and Belgium.</p> <p>Results</p> <p>Of 750 consenting candidates (50.5% of voluntary donors), 71 (9.5%) were deferred by the questionnaire, including 38 specifically because of risk behavior for TTI. Of the 679 non-deferred candidates, 127 (18.7%) had serological confirmation of at least one TTI, with a lower prevalence in voluntary than in replacement donors (15.2% versus 22.4%, p = 0.016). Seroprevalence of HIV, HBsAg and syphilis infections was 8.5%, 10.6 % and 1.2%. No confirmed HCV infection was found. Seroprevalence of TTIs was similar in the 38 candidates deferred for TTI risk as in the non-deferred group, except for HBsAg (26.3 % versus 10.6 %; p = 0.005). The local assays used for HBV and syphilis had sensitivities of 98.4% and 100% and specificities of 80.4% and 98.8% respectively. This resulted in the rejection of 110 of the 679 blood donations (16.2%) because of false positive results.</p> <p>Conclusions</p> <p>The seroprevalence of TTIs after questionnaire screening is high in Tete, Mozambique, but HCV infection does not appear as a major issue. The questionnaire did not exclude effectively HIV-infected donor candidates, while the locally used assays led to unnecessary rejection of many safe donations. A contextualized questionnaire and consistent use of quality-assured assays would considerably improve the current screening procedure for blood donation.</p
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