114 research outputs found

    Industrial Transformation and Development of Heavy Metal Emissions in Northrhine-Westfalia: Decomposition and Material Flow Analysis

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    This paper presents a contribution to the Regional Material Balance Approaches to Long-Term Environmental Policy Planning project (IND project). The policy part of this project - the Ruhr/Katowice Policy Comparison - aims at a better understanding of policy options for cleaning up the Black Triangle. The comparison focuses on the Ruhr Area and the Katowice voivodship which were both identified as hot spots of heavy metal pollution. The Ruhr/Katowice Policy Comparison comprises a historical analysis of the Ruhr Area, which draws heavily on the evidence collected in IIASA's previous Rhine Basin study and which investigates past policies to reduce heavy metal pollution in this area. The investigation was performed by Sander de Bruyn and Simone Schucht during their participation in IIASA's Young Scientists' Summer Program. This paper describes, both quantitatively and qualitatively, the determinants of the reduction of atmospheric heavy metal emissions in Northrhine-Westfalia. It develops methods to describe quantitatively industrial transformation and applies these methods to the analysis of industrial change in Northrhine-Westfalia during the 1955 to 1988 period

    Emission Reduction Through Restructuring of the Non-Ferrous Metal Industry in the Ruhr Area. A Historical Record

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    This working paper describes those determinants of intrasectoral change within the sector of non-ferrous metal production in the Ruhr Area, Northrhine-Westfalia, which contributed to the reduction of atmospheric heavy metal emissions since the mid-sixties, as well as the driving forces behind these intrasectoral changes. It constitutes part of the Rhine/Black Triangle Policy Comparison Study at IIASA. Intrasectoral changes pertaining to the emission of atmospheric heavy metals are shown to have consisted, in the first place, of process changes whose main characteristic was increased processing of production residues, i.e. a closing of economic (material) cycles, thus increasing recycling and decreasing waste. The second most important development was the application of gradually improved off-gas collection and cleaning technologies (end-of-pipe technologies). Closures of old plants also have contributed to the decrease in heavy metal emissions. Although capacities were increased during the period of the investigation (1955 to 1988), these capacity increases were brought about with modernized technologies, which are less emission intensive than those used in the older plants. Three major factors were the driving forces behind the intrasectoral change: developments in legal requirements (air pollution control); economic motivations of the enterprises; and financial support from public institutions. An open question is whether various residues resulting from the more modern processing technologies are, from an environmental point of view, more hazardous than heavy metal emissions

    An Analysis of Clean Air Policies in Northrhine-Westfalia: The Case of Dust and Heavy Metal Emissions Related to the Iron and Steel Industry

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    This working paper describes those determinants of intrasectoral change within the iron and steel production sector in the Ruhr Area, Northrhine-Westfalia (NRW), which have contributed to the reduction of atmospheric heavy metal emissions since the early seventies, as well as the driving forces behind these intrasectoral changes. The aim of this paper is a description, as well as an assessment, of key elements of atmospheric point source and diffuse emission reduction policies related to the iron and steel industry. It constitutes part of the Rhine/Black Triangle Policy Comparison Study at IIASA. Intrasectoral changes pertaining to the reduction of atmospheric heavy metal and dust emissions are shown to have consisted, firstly, of process changes whose main characteristics were a replacement of older crude steel production processes, reductions and changes in fuel input and an increased recycling of residues. The second most important development was the application of gradually improved offgas collection and cleaning technologies. There were four major factors behind the intrasectoral change: developments in legal requirements; financial support from public institutions; economic motivations of the enterprises; and cooperative approaches

    Effects of formalin fixation on polarimetric properties of brain tissue: fresh or fixed?

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    Imaging Mueller polarimetry (IMP) appears as a promising technique for real-time delineation of healthy and neoplastic tissue during neurosurgery. The training of machine learning algorithms used for the image post-processing requires large data sets typically derived from the measurements of formalin-fixed brain sections. However, the success of the transfer of such algorithms from fixed to fresh brain tissue depends on the degree of alterations of polarimetric properties induced by formalin fixation (FF). Comprehensive studies were performed on the FF induced changes in fresh pig brain tissue polarimetric properties. Polarimetric properties of pig brain were assessed in 30 coronal thick sections before and after FF using a wide-field IMP system. The width of the uncertainty region between gray and white matter was also estimated. The depolarization increased by 5% in gray matter and remained constant in white matter following FF, whereas the linear retardance decreased by 27% in gray matter and by 28% in white matter after FF. The visual contrast between gray and white matter and fiber tracking remained preserved after FF. Tissue shrinkage induced by FF did not have a significant effect on the uncertainty region width. Similar polarimetric properties were observed in both fresh and fixed brain tissues, indicating a high potential for transfer learning

    Safe surgery for glioblastoma: recent advances and modern challenges

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    One of the major challenges during glioblastoma surgery is balancing between maximizing extent of resection and preventing neurological deficits. Several surgical techniques and adjuncts have been developed to help identify eloquent areas both preoperatively (fMRI, nTMS, MEG, DTI) and intraoperatively (imaging (ultrasound, iMRI), electrostimulation (mapping), cerebral perfusion measurements (fUS)), and visualization (5-ALA, fluoresceine)). In this review, we give an update of the state-of-the-art management of both primary and recurrent glioblastomas. We will review the latest surgical advances, challenges, and approaches that define the onco-neurosurgical practice in a contemporary setting and give an overview of the current prospective scientific efforts

    Global comparison of awake and asleep mapping procedures in glioma surgery: an international multicenter survey

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    Background Mapping techniques are frequently used to preserve neurological function during glioma surgery. There is, however, no consensus regarding the use of many variables of these techniques. Currently, there are almost no objective data available about potential heterogeneity between surgeons and centers. The goal of this survey is therefore to globally identify, evaluate and analyze the local mapping procedures in glioma surgery. Methods The survey was distributed to members of the neurosurgical societies of the Netherlands (Nederlandse Vereniging voor Neurochirurgie-NVVN), Europe (European Association of Neurosurgical Societies-EANS), and the United States (Congress of Neurological Surgeons-CNS) between December 2020 and January 2021 with questions about awake mapping, asleep mapping, assessment of neurological morbidity, and decision making. Results Survey responses were obtained from 212 neurosurgeons from 42 countries. Overall, significant differences were observed for equipment and its settings that are used for both awake and asleep mapping, intraoperative assessment of eloquent areas, the use of surgical adjuncts and monitoring, anesthesia management, assessment of neurological morbidity, and perioperative decision making. Academic practices performed awake and asleep mapping procedures more often and employed a clinical neurophysiologist with telemetric monitoring more frequently. European neurosurgeons differed from US neurosurgeons regarding the modality for cortical/subcortical mapping and awake/asleep mapping, the use of surgical adjuncts, and anesthesia management during awake mapping. Discussion This survey demonstrates the heterogeneity among surgeons and centers with respect to their procedures for awake mapping, asleep mapping, assessing neurological morbidity, and decision making in glioma patients. These data invite further evaluations for key variables that can be optimized and may therefore benefit from consensus

    Future air quality in Europe: a multi-model assessment of projected exposure to ozone

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    In order to explore future air quality in Europe at the 2030 horizon, two emission scenarios developed in the framework of the Global Energy Assessment including varying assumptions on climate and energy access policies are investigated with an ensemble of six regional and global atmospheric chemistry transport models. <br><br> A specific focus is given in the paper to the assessment of uncertainties and robustness of the projected changes in air quality. The present work relies on an ensemble of chemistry transport models giving insight into the model spread. Both regional and global scale models were involved, so that the ensemble benefits from medium-resolution approaches as well as global models that capture long-range transport. For each scenario a whole decade is modelled in order to gain statistical confidence in the results. A statistical downscaling approach is used to correct the distribution of the modelled projection. Last, the modelling experiment is related to a hind-cast study published earlier, where the performances of all participating models were extensively documented. <br><br> The analysis is presented in an exposure-based framework in order to discuss policy relevant changes. According to the emission projections, ozone precursors such as NO<sub>x</sub> will drop down to 30% to 50% of their current levels, depending on the scenario. As a result, annual mean O<sub>3</sub> will slightly increase in NO<sub>x</sub> saturated areas but the overall O<sub>3</sub> burden will decrease substantially. Exposure to detrimental O<sub>3</sub> levels for health (SOMO35) will be reduced down to 45% to 70% of their current levels. And the fraction of stations where present-day exceedences of daily maximum O<sub>3</sub> is higher than 120 μg m<sup>−3</sup> more than 25 days per year will drop from 43% down to 2 to 8%. <br><br> We conclude that air pollution mitigation measures (present in both scenarios) are the main factors leading to the improvement, but an additional cobenefit of at least 40% (depending on the indicator) is brought about by the climate policy

    The Development of Cephalic Armor in The Tokay Gecko (Squamata: Gekkonidae: \u3cem\u3eGekko gecko\u3c/em\u3e)

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    Armored skin resulting from the presence of bony dermal structures, osteoderms, is an exceptional phenotype in gekkotans (geckos and flap-footed lizards) only known to occur in three genera: Geckolepis, Gekko, and Tarentola. The Tokay gecko (Gekko gecko LINNAEUS 1758) is among the best-studied geckos due to its large size and wide range of occurrence, and although cranial dermal bone development has previously been investigated, details of osteoderm development along a size gradient remain less well-known. Likewise, a comparative survey of additional species within the broader Gekko clade to determine the uniqueness of this trait has not yet been completed. Here, we studied a large sample of gekkotans (38 spp.), including 18 specimens of G. gecko, using X-rays and high-resolution computed tomography for visualizing and quantifying the dermal armor in situ. Results from this survey confirm the presence of osteoderms in a second species within this genus, Gekko reevesii GRAY 1831, which exhibits discordance in timing and pattern of osteoderm development when compared with its sister taxon, G. gecko. We discuss the developmental sequence of osteoderms in these two species and explore in detail the formation and functionality of these enigmatic dermal ossifications. Finally, we conducted a comparative analysis of endolymphatic sacs in a wide array of gekkotans to explore previous ideas regarding the role of osteoderms as calcium reservoirs. We found that G. gecko and other gecko species with osteoderms have highly enlarged endolymphatic sacs relative to their body size, when compared to species without osteoderms, which implies that these membranous structures might fulfill a major role of calcium storage even in species with osteoderms

    Transplantation of Specific Human Astrocytes Promotes Functional Recovery after Spinal Cord Injury

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    Repairing trauma to the central nervous system by replacement of glial support cells is an increasingly attractive therapeutic strategy. We have focused on the less-studied replacement of astrocytes, the major support cell in the central nervous system, by generating astrocytes from embryonic human glial precursor cells using two different astrocyte differentiation inducing factors. The resulting astrocytes differed in expression of multiple proteins thought to either promote or inhibit central nervous system homeostasis and regeneration. When transplanted into acute transection injuries of the adult rat spinal cord, astrocytes generated by exposing human glial precursor cells to bone morphogenetic protein promoted significant recovery of volitional foot placement, axonal growth and notably robust increases in neuronal survival in multiple spinal cord laminae. In marked contrast, human glial precursor cells and astrocytes generated from these cells by exposure to ciliary neurotrophic factor both failed to promote significant behavioral recovery or similarly robust neuronal survival and support of axon growth at sites of injury. Our studies thus demonstrate functional differences between human astrocyte populations and suggest that pre-differentiation of precursor cells into a specific astrocyte subtype is required to optimize astrocyte replacement therapies. To our knowledge, this study is the first to show functional differences in ability to promote repair of the injured adult central nervous system between two distinct subtypes of human astrocytes derived from a common fetal glial precursor population. These findings are consistent with our previous studies of transplanting specific subtypes of rodent glial precursor derived astrocytes into sites of spinal cord injury, and indicate a remarkable conservation from rat to human of functional differences between astrocyte subtypes. In addition, our studies provide a specific population of human astrocytes that appears to be particularly suitable for further development towards clinical application in treating the traumatically injured or diseased human central nervous system
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