Hydrogel membranes based on genipin-cross-linked chitosan blends for corneal epithelium tissue engineering

Novel polymeric hydrogel scaffolds for corneal epithelium cell culturing based on blends of chitosan with some other biopolymers such as hydroxypropylcellulose, collagen and elastin crosslinked with genipin, a natural substance, were prepared. Physicochemical and biomechanical properties of these materials were determined. The in vitro cell culture experiments with corneal epithelium cells have indicated that a membrane prepared from chitosan–collagen blend (Ch–Col) provided the regular stratified growth of the epithelium cells, good surface covering and increased number of the cell layers. Ch–Col membranes are therefore the most promising material among those studied. The performance of Ch–Col membranes is comparable with that of the amniotic membrane which is currently recommended for clinical applications

Quality assurance in stereotactic radiosurgery/radiotherapy according to DIN 6875-1

The new DIN (' Deutsche Industrie- Norm') 6875- 1, which is currently being finalised, deals with quality assurance ( QA) criteria and tests methods for linear accelerator and Gamma Knife stereotactic radiosurgery/ radiotherapy including treatment planning, stereotactic frame and stereotactic imaging and a system test to check the whole chain of uncertainties. Our existing QA program, based on dedicated phantoms and test procedures, has been refined to fulfill the demands of this new DIN. The radiological and mechanical isocentre corresponded within 0.2 mm and the measured 50% isodose lines were in agreement with the calculated ones within less than 0.5 mm. The measured absorbed dose was within 3%. The resultant output factors measured for the 14-, 8- and 4- mm collimator helmet were 0.9870 +/- 0.0086, 0.9578 +/- 0.0057 and 0.8741 +/- 0.0202, respectively. For 170 consecutive tests, the mean geometrical accuracy was 0.48 +/- 0.23 mm. Besides QA phantoms and analysis software developed in- house, the use of commercially available tools facilitated the QA according to the DIN 6875- 1 with which our results complied. Copyright (C) 2004 S. Karger AG, Basel

Development of an LCA-based approach for a regional assessment of the environmental impacts of nitrogen in crop production systems

Agricultural systems are dependent on nitrogen (N) inputs to achieve food security and, at the same time, put high pressure on environmental systems. Accordingly, global limits for N-cycles are already exceeded. However, the release of N compounds from agricultural cropping systems mainly impacts the regional level, for instance, by eutrophication or acidification of terrestrial systems. Therefore, avoiding the exceedance of regional boundaries is essential. Likewise, when assessing environmental impacts on agricultural cropping systems with Life Cycle Assessment (LCA), integration of regional N thresholds and, thus, regionalization plays a crucial role. This thesis aims to provide an LCA-based approach to comprehensively assess N on a regional level by integrating N thresholds as reference values and regionalization in LCA. This thesis is a cumulative dissertation consisting of three peer-reviewed publications. In the first publication, a comprehensive review following the LCA framework is presented by analyzing literature on regionalization approaches applied to agricultural cropping systems compared with general requirements of LCA and the scientific background of the N-cycle. Key factors are derived, formulating the basis for a targeted N assessment in LCA. The second publication presents the development of an approach for integrating regional N resilience as distance-to-target value in LCA. Therefore, regional carrying capacity based normalization references are derived for two N-related impact categories: terrestrial acidification and eutrophication. Additionally, regional background interventions comprising N-related emissions of non-crop production sectors are taken into account. Regional environmental interventions of cropping systems applying different yield scenarios are assessed for two regions. The newly developed approach is further developed within the third publication and applied to a case study including five NUTS-3 regions in Germany. The influence on regional N resilience is evaluated by assessing environmental interventions for four N management scenarios based on policy measures of the German Fertilizer Ordinance. The case study demonstrates that environmental interventions and exceedance of N resilience are lowest in N scenarios applying catch crops for both impact categories assessed. Furthermore, regional differences in the exceedance of N resilience were observed. Overall the analyses done within this thesis revealed that considering absolute sustainability references as regional N resilience in LCA is a valuable tool for agricultural decision-makers. This supports LCA practitioners by providing normalization references directly applicable for LCA and N-assessment of cropping systems. Additionally, it helps regional stakeholders to provide the possibility to evaluate and decide on the best options for N reduction strategies on the regional level and draw attention to vulnerable regions threatening N resilience. Finally, challenges, future research needs, and opportunities for application of the approach are outlined

Machiavellian Ways to Academic Cheating:A Mediational and Interactional Model

Academic cheating has become a pervasive practice from primary schools to university. This study aims at investigating this phenomenon through a nomological network which integrates different theoretical frameworks and models, such as trait and social-cognitive theories and models regarding the approaches to learning and contextual/normative environment. Results on a sample of more than 200 Italian university students show that the Amoral Manipulation facet of Machiavellianism, Academic Moral Disengagement, Deep Approach to Learning, and Normative Academic Cheating are significantly associated with Individual Academic Cheating. Moreover, results show a significant latent interaction effect between Normative Academic Cheating and Amoral Manipulation Machiavellianism: “amoral Machiavellians” students are more prone to resort to Academic Cheating in contexts where Academic Cheating is adopted as a practice by their peers, while this effect is not significant in contexts where Academic Cheating is not normative. Results also show that Academic Moral Disengagement and Deep Approach to learning partially mediate the relationship between Amoral Manipulation and Academic Cheating. Practical implications of these results are discussed

Abandoned agricultural lands in Central and Eastern Europe: biomass production as a sustainable future land management option, and its socio-economic and environmental implications

Following the collapse of the ‘Eastern Bloc’ in 1989, a large area of agricultural land was abandoned in Central and Eastern Europe. This was not only due to the biophysical marginality of the lands but also as a result of comprehensive political, institutional and socio-economic changes during the post-socialist transitions. Since the mid-2000’s the re-cultivation for food crops has already started on some of these lands in Central and Eastern Europe, which indicates potential sustainability challenges. In this context, one of the possible sustainable land management options for abandoned agricultural land is the introduction of a low intensive crop production system such as perennial biomass crops. In a large number of global studies, the use of abandoned agricultural land for biomass production had been suggested to prevent further land use change (LUC) effects due to the expansion of energy crop production worldwide (1)(2). Perennial biomass crops, in particular, are also expected to remedy a number of natural resource management problems such as soil acidification, soil erosion and water quality degradation and to enhance biodiversity in the arable landscape (3). In addition, the production of biomass crops on abandoned agricultural land has potential to create new opportunities for the economically marginal rural regions in Central and Eastern Europe, which are facing serious agricultural decline and the resulting socio-economic challenges. In our research we focused on four countries in Central and Eastern Europe – Ukraine, Romania, Poland and Latvia - to analyse the drivers for land abandonment and the environmental implications, and derived possible land management options for abandoned agricultural land from a literature review. We then suggested the potential land management scenarios of biomass production on these lands using a case study in north-eastern Poland considering the potential trade-offs between socio-economic and environmental effects of the biomass production scenarios

Spinal radiosurgery - efficacy and safety after prior conventional radiotherapy

<p>Abstract</p> <p>Background</p> <p>Conventional external beam radiotherapy is a standard procedure for treatment of spinal metastases. In case of progression spinal cord tolerance limits further radiotherapy in pre-irradiated areas. Spinal stereotactic radiotherapy is a non-invasive option to re-treat pre-irradiated patients. Nevertheless, spinal radiosurgery results in relevant dose deposition within the myelon with potential toxicity. Aim of the study was to retrospectively analyse the efficacy and feasibility for salvage radiosurgery of spinal metastases.</p> <p>Methods</p> <p>During a period of 4 years (2005-2009) 70 lesions in 54 patients were treated in 60 radiosurgery sessions and retrospectively analysed. Clinical (pain, sensory and motor deficit) and radiological (CT/MRI) follow-up data were collected prospectively after radiosurgery. Pain - as main symptom - was classified by the Visual Analogue Scale (VAS) score. Every patient received single session radiosurgery after having been treated first-line with conventionally fractionated radiotherapy. Kaplan-Meier method and life tables were used to analyse freedom from local failure and overall survival.</p> <p>Results</p> <p>At a median follow-up of 14.5 months the actuarial rates of freedom from local failure at 6/12/18 months were 93%, 88% and 85%, respectively. The median radiosurgery dose was 1 × 18 Gy (range 10-28 Gy) to the median 70% isodose. The VAS score of patients with pain (median 6) dropped significantly (median 4, p = 0.002). In 6 out of 7 patients worse sensory or motor deficit after SRS was caused by local or distant failures (diagnosed by CT/MRI). One patient with metastatic renal cell carcinoma developed a progressive complete paraparesis one year after the last treatment at lumbar level L3. Due to multiple surgery and radiosurgery treatments at the lumbar region and further local progression, the exact reason remained unclear. Apart from that, no CTC grade III or higher toxicity has been observed.</p> <p>Conclusions</p> <p>By applying spinal radiosurgery relevant radiation doses can be limited to small parts of the myelon. This prevents myelopathic side effects and makes it an effective and safe treatment option for well-suited patients. Especially for previously irradiated patients with local failure or pain salvage SRS represents a valuable treatment option with high local control rates, low toxicity and significant pain reduction.</p

Understanding the Interplay Among Regulatory Self-Efficacy, Moral Disengagement, and Academic Cheating Behaviour During Vocational Education: A Three-Wave Study

The literature has suggested that to understand the diffusion of unethical conduct in the workplace, it is important to investigate the underlying processes sustaining engagement in misbehaviour and to study what occurs during vocational education. Drawing on social-cognitive theory, in this study, we longitudinally examined the role of two opposite dimensions of the self-regulatory moral system, regulatory self-efficacy and moral disengagement, in influencing academic cheating behaviour. In addition, in line with the theories highlighting the bidirectional relationship between cognitive processes and behaviour, we aimed to also examine the reciprocal influence of behaviour on these dimensions over time. Overall, no previous studies have examined the longitudinal interplay between these variables. The sample included 866 (62.8% female) nursing students who were assessed three times annually from the beginning of their vocational education. The findings from a cross-lagged model confirmed that regulatory self-efficacy and moral disengagement have opposite influences on cheating behaviour, that regulatory self-efficacy negatively influences not only the engagement in misconduct but also the justification mechanisms that allow the divorce between moral standards and action, and that moral disengagement and cheating behaviour reciprocally support each other over time. Specifically, not only did moral disengagement influence cheating behaviour even when controlling for its prior levels, but also cheating behaviour affected moral disengagement one year later, controlling for its prior levels. These findings suggest that recourse to wrongdoing could gradually lead to further normalising this kind of behaviour and morally desensitising individuals to misconduct

Use of autologous epithelium transplantation on various scaffolds to cover tissue loss in oral cavity : long-term observation

Background The aim of this study was to investigate the application of mucous membrane keratinocyte cultures on amniotic membrane and on poly(L-lactic acid) (PLLA) Purasorb PL38 to cover tissue loss in the oral cavity. Developments in molecular biology techniques and tissue engineering allow the culturing and identification of cells that can be anchored in the wound to achieve integrity of the tissue. Transplantation of tissues obtained from the patient's own cells is superior to allogenous transplantation where there is a possibility of transfection, rejection and the need for long-term immunosuppression. Methods In 9 patients (15 procedures) keratinocytes cultured on amniotic membrane and PLLA were transplanted to cover antro-oral fistulas and bone loss after osteoradionecrosis. Results In all 6 patients with outlasting antro-oral fistulas, the defects were healed. In 3 patients with 5 cases of tissue loss after osteoradionecrosis, we obtained healing of the wound in only 1 case. Histological examination of the cultures indicated that cultured cells formed well-differentiated layers, very similar to the keratinocytes of mucous membranes, although those seeded on amniotic membrane formed a single layer of cells, while those seeded on the PLLA scaffold were arranged on 2 or more layers: these differences were shown to be statistically significant with a morphometric analysis. Conclusions Autologous transplants of epithelium cultured on amniotic membrane and PLLA constitute a new and effective way of covering nonhealing tissue loss in the oral cavity in chosen cases, using modern methods of tissue engineering. </jats:sec