Cu,Zn,Al layered double hydroxides as precursors for copper catalysts in methanol steam reforming – pH-controlled synthesis by microemulsion technique

By co-precipitation inside microemulsion droplets a Cu-based catalyst precursor was prepared with a Cu:Zn:Al ratio of 50:17:33. A pH-controlled synthesis was applied by simultaneous dosing of metal solution and precipitation agent. This technique allows for continuous operation of the synthesis and enables easy and feasible up-scaling. For comparison conventional co-precipitation was applied with the same composition. Both techniques resulted in phase pure layered double hydroxide precursors and finally (after calcination and reduction) in small Cu nanoparticles (8 nm) and ZnAl2O4. By applying the microemulsion technique smaller Cu/ZnAl2O4 aggregates with less embedded Cu particles were obtained. The microemulsion product exhibited a higher BET and specific Cu surface area and also a higher absolute catalytic activity in methanol steam reforming. However, the Cu surface area-normalized, intrinsic activity was lower. This observation was related to differences in interactions of Cu metal and oxide phase

Embolization in an adrenocortical carcinoma as palliative therapy

Background: With an annual incidence of 0.2% of new cases per 100,000 inhabitants, adrenocortical carcinoma is rare. In advanced tumor only palliative treatment modalities are practicable. Because of scarcity of the tumor, standard treatment has not been defined. The decision on therapy frequently depends on the individual situation. Tumor embolization and chemotherapy are amongst the possible options. Patient and Methods: We report on a case of a 32-year-old female patient with a large-volume hormonally active adrenocortical carcinoma and hematogenous liver metastases. This carcinoma was confirmed histologically by means of liver biopsy. Owing to the large tumor extent and metastatic spreading and also in view of the poor general condition of the patient, curative surgical therapy was not possible. For this reason, a local approach was chosen primarily with transarterial tumor embolization at the capillary level. Systemic chemotherapy was given afterwards. Results: Improvement of the patient's general condition, especially the pronounced pain symptoms, could be achieved for a short time by the embolization: both, the patient's clinical condition and the laboratory test parameters improved. However, a rapid tumor progression occured under chemotherapy, which was started after embolization. Conclusion: In advanced adrenocortical carcinoma, tumor embolization can lead to a stabilization of the disease and improvement of the symptoms as appraised by palliative criteria in some patients

Photosynthetic acclimation of Symbiodinium in hospite depends on vertical position in the tissue of the scleractinian coral Montastrea curta

© 2016 Lichtenberg, Larkum and Kühl. Coral photophysiology has been studied intensively from the colony scale down to the scale of single fluorescent pigment granules as light is one of the key determinants for coral health. We studied the photophysiology of the oral and aboral symbiont band of scleractinian coral Montastrea curta to investigate if different acclimation to light exist in hospite on a polyp scale. By combined use of electrochemical and fiber-optic microsensors for O2, scalar irradiance and variable chlorophyll fluorescence, we could characterize the physical and chemical microenvironment experienced by the symbionts and, for the first time, estimate effective quantum yields of PSII photochemistry and rates of electron transport at the position of the zooxanthellae corrected for the in-tissue gradient of scalar irradiance. The oral- and aboral Symbiodinium layers received ~71% and ~33% of surface scalar irradiance, respectively, and the two symbiont layers experience considerable differences in light exposure. Rates of gross photosynthesis did not differ markedly between the oral- and aboral layer and curves of PSII electron transport rates corrected for scalar irradiance in hospite, showed that the light use efficiency under sub-saturating light conditions were similar between the two layers. However, the aboral Symbiodinium band did not experience photosynthetic saturation, even at the highest investigated irradiance where the oral layer was clearly saturated. We thus found a different light acclimation response for the oral and aboral symbiont bands in hospite, and discuss whether such response could be shaped by spectral shifts caused by tissue gradients of scalar irradiance. Based on our experimental finding, combined with previous knowledge, we present a conceptual model on the photophysiology of Symbiodinium residing inside living coral tissue under natural gradients of light and chemical parameters

Fine‐scale measurement of diffusivity in a microbial mat with nuclear magnetic resonance imaging

Noninvasive 1H‐nuclear magnetic resonance (NMR) imaging was used to investigate the diffusive properties of microbial mats in two dimensions. Pulsed field gradient NMR was used to acquire images of the H2O diffusion coefficient, Ds, and multiecho imaging NMR was used to obtain images of the water density in two structurally different microbial mats sampled from Solar Lake (Egypt). We found a pronounced lateral and vertical variability of both water density and water diffusion coefficient, correlated with the laminated and heterogeneous distribution of microbial cells and exopolymers within the mats. The average water density varied from 0.5 to 0.9, whereas the average water diffusion coefficient ranged from 0.4 to 0.9 relative to the values obtained in the stagnant water above the mat samples. The apparent water diffusivities estimated from NMR imaging compared well to apparent O2 diffusivities measured with a diffusivity microsensor. Analysis of measured O2 concentration profiles with a diffusion‐reaction model showed that both the magnitude of calculated rates and the depth distribution of calculated O2 consumption/production zones changed when the observed variations of diffusivity were taken into account. With NMR imaging, diffusivity can be determined at high spatial resolution, which can resolve inherent lateral and vertical heterogeneities found in most natural benthic systems

Nanoparticle- and microparticle-based luminescence imaging of chemical species and temperature in aquatic systems: a review

© 2019, Springer-Verlag GmbH Austria, part of Springer Nature. Most aquatic systems rely on a multitude of biogeochemical processes that are coupled with each other in a complex and dynamic manner. To understand such processes, minimally invasive analytical tools are required that allow continuous, real-time measurements of individual reactions in these complex systems. Optical chemical sensors can be used in the form of fiber-optic sensors, planar sensors, or as micro- and nanoparticles (MPs and NPs). All have their specific merits, but only the latter allow for visualization and quantification of chemical gradients over 3D structures. This review (with 147 references) summarizes recent developments mainly in the field of optical NP sensors relevant for chemical imaging in aquatic science. The review encompasses methods for signal read-out and imaging, preparation of NPs and MPs, and an overview of relevant MP/NP-based sensors. Additionally, examples of MP/NP-based sensors in aquatic systems such as corals, plant tissue, biofilms, sediments and water-sediment interfaces, marine snow and in 3D bioprinting are given. We also address current challenges and future perspectives of NP-based sensing in aquatic systems in a concluding section. [Figure not available: see fulltext.]

point cloud analysis for conservation and enhancement of modernist architecture

Documentation of cultural assets through improved acquisition processes for advanced 3D modelling is one of the main challenges to be faced in order to address, through digital representation, advanced analysis on shape, appearance and conservation condition of cultural heritage. 3D modelling can originate new avenues in the way tangible cultural heritage is studied, visualized, curated, displayed and monitored, improving key features such as analysis and visualization of material degradation and state of conservation. An applied research focused on the analysis of surface specifications and material properties by means of 3D laser scanner survey has been developed within the project of Digital Preservation of FAUUSP building, Faculdade de Arquitetura e Urbanismo da Universidade de São Paulo, Brazil. The integrated 3D survey has been performed by the DIAPReM Center of the Department of Architecture of the University of Ferrara in cooperation with the FAUUSP. The 3D survey has allowed the realization of a point cloud model of the external surfaces, as the basis to investigate in detail the formal characteristics, geometric textures and surface features. The digital geometric model was also the basis for processing the intensity values acquired by laser scanning instrument; this method of analysis was an essential integration to the macroscopic investigations in order to manage additional information related to surface characteristics displayable on the point cloud