Optimization of Optical and Mechanical Properties of Real Architecture for 3-Dimensional Tissue Equivalents: Towards Treatment of Limbal Epithelial Stem Cell Deficiency

Limbal epithelial stem cell (LESC) deficiency can cause blindness. Transplantation of cultured human limbal epithelial cells (hLE) on human amniotic membrane (HAM) can restore vision but clinical graft manufacture can be unreliable. We have developed a reliable and robust tissue equivalent (TE) alternative to HAM, Real Architecture for 3D Tissue (RAFT). Here, we aimed to optimize the optical and mechanical properties of RAFT TE for treatment of LESC deficiency in clinical application. The RAFT TE protocol is tunable; varying collagen concentration and volume produces differing RAFT TEs. These were compared with HAM samples taken from locations proximal and distal to the placental disc. Outcomes assessed were transparency, thickness, light transmission, tensile strength, ease of handling, degradation rates and suitability as substrate for hLE culture. Proximal HAM samples were thicker and stronger with poorer optical properties than distal HAM samples. RAFT TEs produced using higher amounts of collagen were thicker and stronger with poorer optical properties than those produced using lower amounts of collagen. The ‘optimal’ RAFT TE was thin, transparent but still handleable and was produced using 0.6 ml of 3 mg/ml collagen. Degradation rates of the ‘optimal’ RAFT TE and HAM were similar. hLE achieved confluency on ‘optimal’ RAFT TEs at comparable rates to HAM and cells expressed high levels of putative stem cell marker p63α. These findings support the use of RAFT TE for hLE transplantation towards treatment of LESC deficiency

Contribution of organic farming to conserving and improving biodiversity in Germany avi-fauna as an example

Although it is the aim of organic farming to increase biodiversity, there is little information about the impact of organic farming on birds. From 2001 to 2003, the number of breeding birds was recorded annually on the organic experimental farm of the Institute of Organic Farming (600 ha), and on adjacent conventional and organic farms (60 ha and 40 ha) in Northern Germany. The number of skylark (Alauda arvensis) territories increased considerably after the conversion from conventional to organic farming on the premises of the Institute. Their number remained unvaried on the conventional farm. The highest density of skylark territories was found on the farm which has been under organic management for many years. The number of yellowhammer (Emberiza citronella) territories fluctuated largely in relation to the availability of field margin strips, both on conventional and organic land. During the breeding season aerial hunters (swallows and swifts) and raptors significantly preferred organic fields. Outside the breeding season, densities of raptors (in autumn and in winter), seed-eating birds (in autumn) and insect-eating birds (in autumn) were significantly higher on organic than on conventional fields

Development of Collembolans after coversion towards organic farming

In Northern Germany, a diverse and complex experimental farm of the Federal Agricultural Research Centre (FAL) was set-up in 2001 covering all main aspects of organic farming. Previously, the 600 ha farm had been managed conventionally. Adjacent conventional farms were used as reference. The aim of this project was to study collembolans, microbial biomass and soil organic carbon in six organically farmed fields managed as a crop rotation of six different crops compared with an adjacent conventionally managed field. We hypothesised that the specific management in organic farming promotes soil biota. Soil samples were taken during the growing season in 2004. Collembolan abundances and microbial biomass were lower under organic management, but, generally, collembolan diversity was higher in organically farmed fields combined with a shifting in the dominance structure of the species. This result reveals that, even after three years, the soil biota is still changing with management conversion

Conceptual design for measuring soil management sustainability

Soils are the nexus of food, energy and water which illustrates the need for a holistic approach in sustainable soil management. The search for relevant bioindicators of soil sustainability has led to a huge output of studies recently, but yet a proper parameter or a set of parameters has not been identified. Resilience is often promoted to be a boundary concept to integrate social and natural dimensions of sustainability. Therefore, resilience is a promising parameter when it comes to measuring sustainability of soil management practices, since it reflects both its highly interlinked ecological and management components. To include both of these two interlinked components, the whole concept of soil ecosystem functioning needs to be reconsidered. We will present a modified concept of soil functioning cycles within the three dimensions of potential, connectedness and resilience. Additionally, we present a first methodological approach of how to measure resilience by the maximum ecological performance (MEP), using the multi-omics approach. We will present resilience as a key element of an adaptive management scheme, to also meet the challenge of deriving information about the link between soil biodiversity and soil multifunctionality

Nonlinear optical properties of a channel waveguide produced with crosslinkable ferroelectric liquid crystals

A binary mixture of ferroelectric liquid crystals (FLCs) was used for the design of a channel waveguide. The FLCs possess two important functionalities: a chromophore with a high hyperpolarizability $\beta$ and photoreactive groups. The smectic liquid crystal is aligned in layers parallel to the glass plates in a sandwich geometry. This alignment offers several advantages, such as that moderate electric fields are sufficient to achieve a high degree of polar order. The arrangement was then permanently fixed by photopolymerization which yielded a polar network possessing a high thermal and mechanical stability which did not show any sign of degradation within the monitored period of several months. The linear and nonlinear optical properties have been measured and all four independent components of the nonlinear susceptibility tensor $\bar d$ have been determined. The off-resonant $d$-coefficients are remarkably high and comparable to those of the best known inorganic materials. The alignment led to an inherent channel waveguide for p-polarized light without additional preparation steps. The photopolymerization did not induce scattering sites in the waveguide and the normalized losses were less than 2 dB/cm. The material offers a great potential for the design of nonlinear optical devices such as frequency doublers of low power laser diodes.Comment: LaTeX2e article, 15 pages, 10 figures, 11 EPS files, submitted to Physical Review

Internet-Unterstützung der Lehre

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Clinician-Patient Small Talk: Comparing Competent Students and Expert Dentists in a Standardized Patient Encounter

poster abstractObjectives: To establish whether the frequency of non-diagnostic, non-management exchanges between clinicians and patient (socioemotional communication, SC) during the consultation differed between senior dental students and dentists, controlling for clinically driven exchanges of information. Methods: Dentists and students were recorded while undergoing a consultation with a live standardized patient, and subsequently interviewed by investigators; their shared interpretation of cognitive strategies were recorded and compared for differences in the presence of SC using a χ2 test; first consultation occurrence of SC using log-rank tests; and number of times that SC occurred using mixed-model ANOVA. Results: Most clinicians engaged in SC throughout the consultation with a few exceptions. Statistical analyses produced non-significant differences for overall SC presence (p=0.62), time to first instance of SC from overall start of the consultation (p=0.73), and time after first intraoral examination had taken place (p=0.76). Non-significant differences were also recorded for the summary of time intervals when SC occurred at time from overall start of the consultation (p=0.89), and time after first intra-oral examination had taken place (p=0.12). Conclusions: SC occurred in most clinicians. Patterns depicted this interaction occurring throughout the consultation, not concentrated at the beginning or end. SC did not appear to differ between experts and students in terms of prevalence, frequency, or timing. Future research should examine the detailed association between SC and diagnostic thinking processes, to further delineate their relationship and characterize possible pedagogical applications

Labeling of Peroxisomes for Live Cell Imaging in the Filamentous Fungus Ustilago maydis

This is the author accepted manuscript. The final version is available from Humana Press via the DOI in this record.The basidiomycete fungus Ustilago maydis has emerged as a powerful model organism to study fundamental biological processes. U. maydis shares many important features with human cells but provides the technical advantages of yeast. Recently, U. maydis has also been used to investigate fundamental processes in peroxisome biology. Here, we present an efficient yeast recombination-based cloning method to construct and express fluorescent fusion proteins (or conditional mutant protein alleles) which target peroxisomes in the fungus U. maydis. In vivo analysis is pivotal for understanding the underlying mechanisms of organelle motility. We focus on the in vivo labelling of peroxisomes in U. maydis and present approaches to analyze peroxisomal motility.We would like to thank G. Steinberg for his support and the opportunity to publish this method chapter. This work was supported by the Portuguese Foundation for Science and Technology and FEDER/COMPETE (SFRH/BD/73532/2010 to S.C. Guimarães) and CRUP/Treaty of Windsor (ACÇÕES INTEGRADAS 2009, B-33/09 to G. Steinberg and M. Schrader). M. Schrader acknowledges support from the Marie Curie Initial Training Network (ITN) action (FP7-2012 PERFUME-316723)