Zystische Adventitiadegeneration (CAD) als Ursache einer invalidisierenden Claudicatio intermittens

Zusammenfassung: Bei einem 45-jährigen Patienten mit wechselhaften Ischämiebeschwerden und initial limitierter Gehstrecke rechts von höchstens 50m führten die duplexsonographischen und angiographischen Abklärungen zur Verdachtsdiagnose einer zystischen Adventitiadegeneration. Intraoperativ zeigte sich ein zystisch aufgetriebenes Poplitealsegment mit Entleerung von gallertiger Flüssigkeit. Aufgrund der langstreckigen Veränderung erfolgte die Segmentresektion der A.poplitea und Rekonstruktion mittels eines autologen Veneninterponats. Die CAD ist ein seltenes Krankheitsbild, an das gerade bei jungen Patienten ohne systemische Arteriosklerose gedacht werden sollte. Die Therapie ist je nach Fall chirurgisch erhaltend durch Zystenresektion mittels "Exarterektomie" oder gefäßresezierend, insbesondere bei langstreckigen Veränderungen bzw. vollständiger Okklusion mittels Ersatz durch ein Veneninterpona

Structure of Extremely Nanosized and Confined In-O Species in Ordered Porous Materials

Perturbed-angular correlation, x-ray absorption, and small-angle x-ray scattering spectroscopies were suitably combined to elucidate the local structure of highly diluted and dispersed InOx species confined in porous of ZSM5 zeolite. These novel approach allow us to determined the structure of extremely nanosized In-O species exchanged inside the 10-atom-ring channel of the zeolite, and to quantify the amount of In2O3 crystallites deposited onto the external zeolite surface.Comment: 4 pages, 5 postscript figures, REVTEX4, published in Physical Review Letter

Functional Dynamics of Phytoplankton Assemblages in Hypertrophic Lakes: Functional- and Species Diversity is Highly Resistant to Cyanobacterial Blooms

Under increasing pressure of climatic change and anthropogenic eutrophication, water blooms, i.e. the formation of high phytoplankton biomass of a single or a few species, have become more and more frequent in lake ecosystems that is caused mostly by Cyanobacteria. The dynamics of phytoplankton under a cyanobacterial pressure may provide important information about what a competitive advantage of Cyanobacteria have over eukaryotic microalgae. The research, therefore focused on the relationship between cyanobacterial blooms and the accompanying species in hypertrophic shallow lakes where nutrients are in excess. The following hypotheses were selected for testing: i) Cyanobacterial blooms negatively affect the species richness and diversity of phytoplankton assemblages in the studied hypertrophic lakes. ii) Cyanobacterial blooms negatively affect the multi-trait functional diversity of phytoplankton assemblages in the studied hypertrophic lakes. iii) The formation of a cyanobacterial bloom causes a shift in the species and trait composition of phytoplankton assemblages. It was found that the species diversity of non-cyanobacterial assemblages was not affected negatively by increasing density of Cyanobacteria. Cyanobacterial biomass negatively affected the functional richness and functional dispersion of the assemblages, but both relationships were only marginally significant. Some temporal shift was detected in the community weighted mean values of width, colonial ability of accompanying microalgae, and also in flagellatedness and mixotrophic ability. We conclude that Cyanobacterial blooms basically alter dominance relations in the phytoplankton and reduce availability of light in waters. However, it does not necessarily coincide with the elimination of other taxa and reduction their species numbers or diversity. The formerly published data on the decrease in species richness can be likely explained by methodological deficiencies, which are responsible for reduced detectability of species. To better understand the seasonal dynamics and resilience of phytoplankton assemblages in hypertrophic water bodies the development of new methodologies by which diversity and succession of subordinate species can be evaluated is required

Longitudinal unzipping of carbon nanotubes to form graphene nanoribbons.

Published versio

Modeling of graphite oxide

Based on density functional calculations, optimized structures of graphite oxide are found for various coverage by oxygen and hydroxyl groups, as well as their ratio corresponding to the minimum of total energy. The model proposed describes well known experimental results. In particular, it explains why it is so difficult to reduce the graphite oxide up to pure graphene. Evolution of the electronic structure of graphite oxide with the coverage change is investigated.Comment: 12 pages, 7 figures. Discussion about reduction to pure graphene and several references added. Methodological part expanded. Accepted to J. Am. Chem. So

Computational studies for reduced graphene oxide in hydrogen-rich environment

We employ molecular dynamic simulations to study the reduction process of graphene-oxide (GO) in a chemically active environment enriched with hydrogen. We examine the concentration and pressure of hydrogen gas as a function of temperature in which abstraction of oxygen is possible with minimum damage to C-sp$^2$ bonds hence preserving the integrity of the graphene sheet. Through these studies we find chemical pathways that demonstrate beneficiary mechanisms for the quality of graphene including formation of water as well as suppression of carbonyl pair holes in favor of hydroxyl and epoxy formation facilitated by hydrogen gas in the environment.Comment: 9 pages and 9 figures. Animations and movies are available at: http://qmsimulatorgojpc.wordpress.com

Graphene Oxide-Gallic Acid Nanodelivery System for Cancer Therapy

Despite the technological advancement in the biomedical science, cancer remains a life-threatening disease. In this study, we designed an anticancer nanodelivery system using graphene oxide (GO) as nanocarrier for an active anticancer agent gallic acid (GA). The successful formation nanocomposite (GOGA) was characterized using XRD, FTIR, HRTEM, Raman, and UV/Vis spectroscopy. The release study shows that the release of GA from the designed anticancer nanocomposite (GOGA) occurs in a sustained manner in phosphate-buffered saline (PBS) solution at pH 7.4. In in vitro biological studies, normal fibroblast (3T3) and liver cancer cells (HepG2) were treated with different concentrations of GO, GOGA, and GA for 72 h. The GOGA nanocomposite showed the inhibitory effect to cancer cell growth without affecting normal cell growth. The results of this research are highly encouraging to go further for in vivo studies

NMR-Based Structural Modeling of Graphite Oxide Using Multidimensional 13C Solid-State NMR and ab Initio Chemical Shift Calculations

Chemically modified graphenes and other graphite-based materials have attracted growing interest for their unique potential as lightweight electronic and structural nanomaterials. It is an important challenge to construct structural models of noncrystalline graphite-based materials on the basis of NMR or other spectroscopic data. To address this challenge, a solid-state NMR (SSNMR)-based structural modeling approach is presented on graphite oxide (GO), which is a prominent precursor and interesting benchmark system of modified graphene. An experimental 2D C-13 double-quantum/single-quantum correlation SSNMR spectrum of C-13-labeled GO was compared with spectra simulated for different structural models using ab initio geometry optimization and chemical shift calculations. The results show that the spectral features of the GO sample are best reproduced by a geometry-optimized structural model that is based on the Lerf-Klinowski model (Lerf, A. et al. Phys. Chem. B 1998, 102, 4477); this model is composed of interconnected sp(2), 1,2-epoxide, and COH carbons. This study also convincingly excludes the possibility of other previously proposed models, including the highly oxidized structures involving 1,3-epoxide carbons (Szabo, I. et al. Chem. Mater. 2006, 18, 2740). C-13 chemical shift anisotropy (CSA) patterns measured by a 2D C-13 CSA/isotropic shift correlation SSNMR were well reproduced by the chemical shift tensor obtained by the ab initio calculation for the former model. The approach presented here is likely to be applicable to other chemically modified graphenes and graphite-based systems