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

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

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

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

Vestibular Function and Quality of Life in Vestibular Schwannoma: Does Size Matter?

Objectives: Patients with vestibular schwannoma (VS) frequently suffer from disabling vestibular symptoms. This prospective follow-up study evaluates vestibular and auditory function and impairment of quality of life due to vertigo, dizziness, and imbalance in patients with unilateral VS of different sizes before/after microsurgical or radiosurgical treatment. Methods: Thirty-eight patients with unilateral VS were included. Twenty-two received microsurgery, 16 CyberKnife radiosurgery. Two follow-ups took place after a median of 50 and 186.5 days. Patients received a standardized neuro-ophthalmological examination, electronystagmography with bithermal caloric testing, and pure-tone audiometry. Quality of life was evaluated with the Dizziness Handicap Inventory (DHI). Patient data was grouped and analyzed according to the size of the VS (group 1: <20 mm vs group 2: ≥20 mm). Results: In group 1, the median loss of vestibular function was +10.5% as calculated by Jongkees Formula (range −43 to +52; group 2: median +36%, range −56 to +90). The median change of DHI scores was −9 in group 1 (range −68 to 30) and +2 in group 2 (−54;+20). Median loss of hearing was 4 dB (−42; 93) in group 1 and 12 dB in group 2 (5; 42). Conclusion: Loss of vestibular function in VS clearly correlates with tumor size. However, loss of vestibular function was not strictly associated with a long-term deterioration of quality of life. This may be due to central compensation of vestibular deficits in long-standing large tumors. Loss of hearing before treatment was significantly influenced by the age of the patient but not by tumor size. At follow-up 1 and 2, hearing was significantly influenced by the size of the VS and the manner of treatment

Quality of life in the follow-up of uveal melanoma patients after CyberKnife treatment

To assess quality of life in uveal melanoma patients within the first and second year after CyberKnife radiosurgery. Overall, 91 uveal melanoma patients were evaluated for quality of life through the Short-form (SF-12) Health Survey at baseline and at every follow-up visit over 2 years after CyberKnife radiosurgery. Statistical analysis was carried out using SF Health Outcomes Scoring Software and included subgroup analysis of patients developing secondary glaucoma and of patients maintaining a best corrected visual acuity (BCVA) of the treated eye of 0.5 log(MAR) or better. Analysis of variance, Greenhouse-Geisser correction, Student's t-test, and Fisher's exact test were used to determine statistical significance. Physical Functioning (PF) and Role Physical (RP) showed a significant decrease after CyberKnife radiosurgery, whereas Mental Health (MH) improved (P=0.007, P<0.0001 and P=0.023). MH and Social Functioning (SF) increased significantly (P=0.0003 and 0.026) in the no glaucoma group, MH being higher compared with glaucoma patients (P=0.02). PF and RP were significantly higher in patients with higher BCVA at the second follow-up (P=0.02). RP decreased in patients with BCVA<0.5 log(MAR) (P=0.013). Vitality (VT) increased significantly in patients whose BCVA could be preserved (P=0.031). Neither tumor localization nor size influenced the development of secondary glaucoma or change in BCVA. Although PF and RP decreased over time, MH improved continuously. Prevention of secondary glaucoma has a significant influence on both SF and MH, whereas preservation of BCVA affects VT. Emotional stability throughout follow-up contributes positively toward overall quality of life. CyberKnife radiosurgery may contribute to attenuation of emotional distress in uveal melanoma patients