Triple-source saddle-curve cone-beam photon counting CT image reconstruction:A simulation study

Purpose: The most common detector material in the PC CT system, cannot achieve the best performance at a relatively higher photon flux rate. In the reconstruction view, the most commonly used filtered back projection, is not able to provide sufficient reconstructed image quality in spectral computed tomography (CT). Developing a triple-source saddle-curve cone-beam photon counting CT image reconstruction method can improve the temporal resolution. Methods: Triple-source saddle-curve cone-beam trajectory was rearranged into four trajectory sets for simulation and reconstruction. Projection images in different energy bins were simulated by forward projection and photon counting CT respond model simulation. After simulation, the object was reconstructed using Katsevich's theory after photon counts correction using the pseudo inverse of photon counting CT response matrix. The material decomposition can be performed based on images in different energy bins. Results: Root mean square error (RMSE) and structural similarity index (SSIM) are calculated to quantify the image quality of reconstruction images. Compared with FDK images, the RMSE for the triple-source image was improved by 27%, 21%, 14%, 8%, and 6% for the reconstrued image of 20–33, 33–47, 47–58, 58–69, 69–80 keV energy bin. The SSIM was improved by 1.031%, 0.665%, 0.396%, 0.235%, 0.174% for corresponding energy bin. The decomposition image based on corrected images shows improved RMSE and SSIM, each by 33.861% and 0.345%. SSIM of corrected decomposition image of iodine reaches 99.415% of the original image. Conclusions: A new Triple-source saddle-curve cone-beam PC CT image reconstruction method was developed in this work. The exact reconstruction of the triple-source saddle-curve improved both the image quality and temporal resolution

Predicting and auralizing acoustics in classrooms

Although classrooms have fairly simple geometries, this type of room is known to cause problems when trying to predict their acoustics using room acoustics computer modeling. Some typical features from a room acoustics point of view are: Parallel walls, low ceilings (the rooms are flat), uneven distribution of absorption, and most of the floor being covered with furniture which at long distances act as scattering elements, and at short distance provide strong specular components. The importance of diffraction and scattering is illustrated in numbers and by means of auralization, using ODEON 8 Beta

Bcl-xL (S49) and (S62) sequential phosphorylation/dephosphorylation during mitosis prevents chromosome instability and aneuploidy

Une caractéristique intéressante de la protéine Bcl-xL est la présence d'un domaine en boucle non-structurée entre les hélices α1 and α2 de la protéine. Ce domaine protéique n'est pas essentiel pour sa fonction anti-apoptotique et absent chez CED-9, la protéine orthologue chez Caenorhabditis elegans. A l'intérieur de ce domaine, Bcl-xL subit une phosphorylation et déphosphorylation dynamique sur les résidus Ser49 et Ser62 en phase G2 du cycle cellulaire et lors de la mitose. Lorsque ces résidus sont mutés et les protéines exprimées dans des cellules cancéreuses, les cellules démontrent plusieurs défauts mitotiques liés à l'instabilité chromosomique. Pour analyser les effets de Bcl-xL Ser49 et Ser62 dans les cellules normales, les présentes études ont été réalisées dans des cellules diploïdes humaines normales, et in vivo chez Caenorhabditis elegans. Dans une première étude, nous avons utilisé la lignée cellulaire de cellules fibroblastiques diploïdes humaines normales BJ, exprimant Bcl-xL (type sauvage), (S49A), (S49D), (S62A), (S62D) et les double (S49/62A) et (S49/62D) mutants. Les cellules exprimant les mutants de phosphorylation ont montré des cinétiques de doublement de la population cellulaire réduites. Ces effets sur la cinétique de doublement de la population cellulaire corrèle avec l'apparition de la sénescence cellulaire, sans impact sur les taux de mort cellulaire. Ces cellules sénescentes affichent des phénotypes typiques de sénescence associés notamment à haut niveau de l'activité β-galactosidase associée à la sénescence, la sécrétion d' interleukine-6, l'activation de p53 et de p21WAF1/ Cip1, un inhibiteur des complexes kinase cycline-dépendant, ainsi que la formation de foyers de chromatine nucléaire associés à γH2A.X. Les analyses de fluorescence par hybridation in situ et des caryotypes par coloration au Giemsa ont révélé que l'expression des mutants de phosphorylation de Bcl-xL provoquent de l'instabilité chromosomique et l'aneuploïdie. Ces résultats suggèrent que les cycles de phosphorylation et déphosphorylation dynamiques de Bcl-xL Ser49 et Ser62 sont importants dans le maintien de l'intégrité des chromosomes lors de la mitose dans les cellules normales. Dans une deuxième étude, nous avons entrepris des expériences chez Caenorhabditis elegans pour comprendre l'importance des résidus Ser49 et Ser62 de Bcl-xL in vivo. Les vers transgéniques portant les mutations de Bcl-xL (S49A, S62A, S49D, S62D et S49/62A) ont été générés et leurs effets ont été analysés sur les cellules germinales des jeunes vers adultes. Les vers portant les mutations de Bcl-xL ont montré une diminution de ponte et d'éclosion des oeufs, des variations de la longueur de leurs régions mitotiques et des zones de transition, des anomalies chromosomiques à leur stade de diplotène, et une augmentation de l'apoptose des cellules germinales. Certaines de ces souches transgéniques, en particulier les variants Ser/Ala, ont également montré des variations de durée de vie par rapport aux vers témoins. Ces observations in vivo ont confirmé l'importance de Ser49 et Ser62 à l'intérieur du domaine à boucle de Bcl-xL pour le maintien de la stabilité chromosomique. Ces études auront une incidence sur les futures stratégies visant à développer et à identifier des composés qui pourraient cibler non seulement le domaine anti-apoptotique de la protéine Bcl-xL, mais aussi son domaine mitotique pour la thérapie du cancer.An interesting feature of Bcl-xL protein is the presence of an unstructured loop domain between its α1 and α2 helices, a domain not essential for its anti-apoptotic function and absent in CED-9, ortholog protein in Caenorhabditis elegans. Within this domain, Bcl-xL undergoes dynamic phosphorylation and dephosphorylation at Ser49 and Ser62 during G2 and mitosis in human cancer cells. When these residues are mutated and proteins expressed in cancer cells, cells harbor mitotic defects, including chromosome mis-attachment, lagging, bridging and mis-segregation, events associated with chromosome instability and aneuploidy. To further analyze the effects of Bcl-xL Ser49 and Ser62 in normal cells, the present studies were performed in normal human diploid cells, and in vivo in Caenorhabditis elegans. First, we studied normal human diploid BJ foreskin fibroblast cells expressing Bcl-xL(wild type), (S49A), (S49D), (S62A), (S62D) and the dual (S49/62A) and (S49/62D) mutants. Cells expressing S49 and/or S62 phosphorylation mutants showed reduced kinetics of cell population doubling. These effects on cell population doubling kinetics correlated with early outbreak of senescence with no impact on the cell death rate. Senescent cells displayed typical senescence-associated phenotypes including high-level of senescence-associated β-galactosidase activity, interleukin-6 secretion, tumor suppressor p53 and cyclin-dependent kinase inhibitor p21Waf1/Cip1 activation as well as γH2A.X-associated nuclear chromatin foci. Fluorescence in situ hybridization analysis and Giemsa-banded karyotypes revealed that the expression of Bcl-xL phosphorylation mutants in normal diploid BJ cells provoked chromosome instability and aneuploidy. These findings suggest that dynamic Bcl-xL Ser49 and Ser62 phosphorylation/ dephosphorylation cycles are important in the maintenance of chromosome integrity during mitosis in normal cells. Second, we undertook experiments in Caenorhabditis elegans to understand the importance of Bcl-xL Ser49 and Ser62 in vivo. Transgenic worms carrying single-site S49A, S62A, S49D, S62D and dual-site S49/62A mutants were generated and their effects were analyzed in germlines of young adult worms. Worms expressing Bcl-xL variants showed decreased egg-laying and hatching, variations in the length of their mitotic regions and transition zones, chromosomal abnormalities at their diplotene stages, and increased germline apoptosis. Some of these transgenic strains, particularly the Ser to Ala variants, also showed slight modulations of lifespan compared to their controls. The in vivo observations confirmed the importance of Ser49 and Ser62 within the loop domain of Bcl-xL in maintaining chromosome stability. These studies could impact future strategies aiming to develop and identify compounds that could target not only the anti-apoptotic domain of Bcl-xL protein, but also its mitotic domain for cancer therapy

Integrative Assessment and Modelling of the Non Timber Forest Products Potential in Nuba Mountains of Sudan by Field Methods, Remote Sensing and GIS

Pressure imposed at any one place or point in time results in a complexity of spatial and temporal interactions within topographical ecosystems. It can be propagated through the system and may have implications for future ecosystem functions over a wide array of various spatial and temporal scales. Under conditions of wars and other socio-economic conflicts, these processes are most forceful in developing countries amidst declining economic growth, lack of awareness, deterioration of ecosystem services, loss of existing traditional knowledge bases and weak governance structures. Forests are an essential part of ecosystem services, not only as a resource but as a contributor to biological systems as well. They represent one of the most important sectors in the context of Environmental Change (EC), both from the point of mitigation as well as adaptation. While forests are projected to be adversely impacted under EC, they are also providing opportunities to mitigate these changes. Yet this is one of the least understood sectors, especially at the regional level - many of its fundamental metrics such as mitigation potential, vulnerability and the likely impacts of EC are still not well understood until now. Thus, there is a need for research and field investigations into the synergy of mitigation and adaptation so that the cost of addressing EC impacts can be reduced and the co-benefits can be increased. The aim of this study is to focus particularly on forest-based ecosystem services and to use forests as a strategy for inducing environmental change within the Nuba Mountains in Sudan, specifically for systems in poor condition under EC, and furthermore to explore forests as an entry point for investigating the relationship between urban and rural development and ecosystem services. In addition, the aim is also to raise understanding of the relations between patterns of local-level economic and demographic changes, the nature and value of local ecosystem services, and the role of such services in increasingly interlinked urban and rural livelihood systems. The methodology applied in the current research is three-pronged: a formal literature review, a socio–economic survey (based on semi-structured interviews of household heads via Rapid Rural Appraisal (RRA), with a focus on group discussions, informal meetings, free listening and key informant techniques), and multitemporal optical satellite data analysis (i.e. Landsat and RapidEye). Landsat imagery was utilized to gather the spatial characteristics of the region and to study the Land Use/Land Cover (LU/LC) changes during the period from 1984 to 2014. Meanwhile, RapidEye imagery was used to generate the tree species distribution map. Qualitative and quantitative techniques were applied to analyze socio-economic data. Moreover, Food Consumption Score (FCS) was used to gauge both diversity and frequency of food consumption in surveyed areas. Geographic object-based image analysis (i.e. K-Nearest Neighbour classifier and knowledge-based classifiers) based on a developed model of integrated features (such as vegetation indices, DEM, thematic layers and meteorological information) was applied. Post Classification Analysis (PCA) as well as Post Change Detection (PCD) techniques were used. Hotspot analysis was conducted to detect the areas affected by deforestation. Furthermore, Ordinary Least Squares regression (OLS), Autocorrelation (Moran's) analysis, and Geographically Weighted Regression analyses (GWR) were applied to address the interaction of the different socioeconomic/ecological factors on Non Timber Forest Products (NTFPs) collection and to simulate the dependency scenarios of NTFPs along with their impact on poverty alleviation. Additionally, simulation was performed to estimate the future forest density and predict the dependency on forest services. An increasing impact of intensive interactions between the rural and urban areas has long been acknowledged. However, recent changes in the global political economy and environmental systems, as well as local dynamics of the study area driven by war, drought and deforestation, have led to an increasing rapidity and depth in rural transformation, as well as to a significant impact on urban areas. Like most environmental problems, the effects of these drivers are complex and are stressed diversely across different geographic regions by the socio-political processes that underlie recent economic and cultural globalization. These interactions and processes have increasingly brought rapid changes in land cover, social, institutional and livelihood transformation across broad areas of South Kordofan. Moreover, the study unveils new dynamics such as high rates of migration and mobility by the indigenous population and the increasing domination of market-centric livelihoods in many villages that were once dominated by rural agricultural and natural resourcesbased socio-economic systems. Furthermore, the research highlights the significant roles of NTFPs and trees in contributing to Nuba Mountains’ economic development, food security and environmental health, indicating which requirements need to be addressed in order to improve these potentials. The study proves that drawing on a wide range of these products for livelihood strengthens rural people’s ability to deal with and adapt to both EC and extreme events. Moreover, the results underline the importance of participatory approaches of rural women and their impact on NTFPs management with recommendations of more emphasis on potential roles and the ability of women to participate in public fora. Furthermore, the study shows that the use of high-resolution satellite imagery, integrated with model-based terrestrial information, provides a precise knowledge about the magnitude and distribution of LU/LC patterns. These methods can make an important contribution towards a better understanding of EC dynamics over time. The study reveals that more information exchange is needed to inform actors and decision makers regarding specific experiences, capacity gaps and knowledge to address EC. Subsequently, new policies and strategies are required to much more specifically focus on how to deal with consequences of longer-term EC rather than with the impacts of sudden natural disasters