3,378 research outputs found

    Improving Loss Estimation for Woodframe Buildings. Volume 2: Appendices

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    This report documents Tasks 4.1 and 4.5 of the CUREE-Caltech Woodframe Project. It presents a theoretical and empirical methodology for creating probabilistic relationships between seismic shaking severity and physical damage and loss for buildings in general, and for woodframe buildings in particular. The methodology, called assembly-based vulnerability (ABV), is illustrated for 19 specific woodframe buildings of varying ages, sizes, configuration, quality of construction, and retrofit and redesign conditions. The study employs variations on four basic floorplans, called index buildings. These include a small house and a large house, a townhouse and an apartment building. The resulting seismic vulnerability functions give the probability distribution of repair cost as a function of instrumental ground-motion severity. These vulnerability functions are useful by themselves, and are also transformed to seismic fragility functions compatible with the HAZUS software. The methods and data employed here use well-accepted structural engineering techniques, laboratory test data and computer programs produced by Element 1 of the CUREE-Caltech Woodframe Project, other recently published research, and standard construction cost-estimating methods. While based on such well established principles, this report represents a substantially new contribution to the field of earthquake loss estimation. Its methodology is notable in that it calculates detailed structural response using nonlinear time-history structural analysis as opposed to the simplifying assumptions required by nonlinear pushover methods. It models physical damage at the level of individual building assemblies such as individual windows, segments of wall, etc., for which detailed laboratory testing is available, as opposed to two or three broad component categories that cannot be directly tested. And it explicitly models uncertainty in ground motion, structural response, component damageability, and contractor costs. Consequently, a very detailed, verifiable, probabilistic picture of physical performance and repair cost is produced, capable of informing a variety of decisions regarding seismic retrofit, code development, code enforcement, performance-based design for above-code applications, and insurance practices

    PSAPP mice exhibit regionally selective reductions in gliosis and plaque deposition in response to S100B ablation

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    <p>Abstract</p> <p>Background</p> <p>Numerous studies have reported that increased expression of S100B, an intracellular Ca<sup>2+ </sup>receptor protein and secreted neuropeptide, exacerbates Alzheimer's disease (AD) pathology. However, the ability of S100B inhibitors to prevent/reverse AD histopathology remains controversial. This study examines the effect of S100B ablation on <it>in vivo </it>plaque load, gliosis and dystrophic neurons.</p> <p>Methods</p> <p>Because S100B-specific inhibitors are not available, genetic ablation was used to inhibit S100B function in the PSAPP AD mouse model. The PSAPP/S100B<sup>-/- </sup>line was generated by crossing PSAPP double transgenic males with S100B<sup>-/- </sup>females and maintained as PSAPP/S100B<sup>+/- </sup>crosses. Congo red staining was used to quantify plaque load, plaque number and plaque size in 6 month old PSAPP and PSAPP/S100B<sup>-/- </sup>littermates. The microglial marker Iba1 and astrocytic marker glial fibrillary acidic protein (GFAP) were used to quantify gliosis. Dystrophic neurons were detected with the phospho-tau antibody AT8. S100B immunohistochemistry was used to assess the spatial distribution of S100B in the PSAPP line.</p> <p>Results</p> <p>PSAPP/S100B<sup>-/- </sup>mice exhibited a regionally selective decrease in cortical but not hippocampal plaque load when compared to PSAPP littermates. This regionally selective reduction in plaque load was accompanied by decreases in plaque number, GFAP-positive astrocytes, Iba1-positive microglia and phospho-tau positive dystrophic neurons. These effects were not attributable to regional variability in the distribution of S100B. Hippocampal and cortical S100B immunoreactivity in PSAPP mice was associated with plaques and co-localized with astrocytes and microglia.</p> <p>Conclusions</p> <p>Collectively, these data support S100B inhibition as a novel strategy for reducing cortical plaque load, gliosis and neuronal dysfunction in AD and suggest that both extracellular as well as intracellular S100B contribute to AD histopathology.</p

    BA11 FKBP5 expression levels correlate with dendritic spine density in postmortem PTSD and controls

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    AbstractGenetic variants of the immunophilin FKBP5 have been implicated in susceptibility to post-traumatic stress disorder (PTSD) and other stress-related disorders. We examined the relationship between mushroom, stubby, thin and filopodial spine densities measured with Golgi staining and FKBP5 gene expression in the medial orbitofrontal cortex (BA11) in individuals diagnosed with PTSD and normal controls (n = 8/8). ANCOVA revealed PTSD cases had a significantly elevated density of stubby spines (29%, P < 0.037) and a trend for a reduction in mushroom spine density (25%, p < 0.082). Levels of FKBP5 mRNA were marginally elevated in the PTSD cases (z = 1.94, p = 0.053) and levels correlated inversely with mushroom (Spearman's rho = −0.83, p < 0.001) and overall spine density (rho = −0.75, p < 0.002) and directly with stubby spine density (rho = 0.55, p < 0.027). These data suggest that FKBP5 may participate in a cellular pathway modulating neuronal spine density changes in the brain, and that this pathway may be dysregulated in PTSD

    Synthesis, Structure, and Reactivity of Zirconium and Hafnium Imido Metalloporphyrins

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    The zirconium and hafnium porphyrin imido complexes (TTP)MNAriPr [TTP = meso-tetra-p-tolylporphyrinato dianion, M = Zr (1), Hf (2), AriPr = 2,6-diisopropylphenyl] were synthesized from (TTP)MCl2 and 2 equiv of LiNHAriPr. The zirconium imido complex, (TTP)ZrNAriPr, was also obtained from the preformed imido complex Zr(NAriPr)Cl2(THF)2 and (TTP)Li2(THF)2. Treatment of (TTP)HfCl2 with excess LiNH(p-MeC6H4) resulted in the formation of a bis(amido) complex, (TTP)Hf(NH-p-MeC6H4)2 (3), instead of an imido complex. In the presence of excess aniline, 2 formed an equilibrium mixture of bis(amido) compounds, (TTP)Hf(NHPh)(NHAriPr) and (TTP)Hf(NHPh)2. The nucleophilic character of the imido moiety is exhibited by its reaction with tBuNCO, producing isolable N,O-bound ureato metallacycles. The kinetic product obtained with zirconium, (TTP)Zr(η2-NAriPrC(NtBu)O) (4a), isomerized to (TTP)Zr(η2-NtBuC(NAriPr)O) (4b) in solution. Upon being heated to 80 °C, 4a produced the carbodiimide AriPrNCNtBu and a transient Zr(IV) oxo complex. The analogous hafnium complex (TTP)Hf(η2-NAriPrC(NtBu)O) (5a) did not eject the carbodiimide upon heating to 110 °C but isomerized to (TTP)Hf(η2-NtBuC(NAriPr)O) (5b). To support the formulation of 4a and 5a as N,O bound, the complex (TTP)Hf(η2-NAriPrC(NAriPr)O) (6) was studied by variable-temperature NMR spectroscopy. The corresponding thio- and selenoureato metallacycles were not isolable in the reaction between 1 and 2 with tBuNCS and tBuNCSe. Concomitant formation of the metallacycle with decomposition to the carbodiimide, AriPrNCNtBu, reflects the lower C−Ch bond strength in the proposed N,Ch-bound metallacycles. Treatment of 2 with 1,3-diisopropylcarbodiimide resulted in the η2-guanidino complex (TTP)Hf(η2-NAriPrC(NiPr)NiPr) (7a), which isomerized to the less sterically crowded isomer (TTP)Hf(η2-NiPrC(NAriPr)NiPr) (7b). Complexes 1, 2, 4a, 4b, and7a were characterized by X-ray crystallography. The monomeric terminal imido compounds, 1and 2, are isomorphous:  M−Nimido distances of 1.863(2) Å (Zr) and 1.859(2) Å (Hf); M−Nimido−C angles of 172.5(2)° (Zr) and 173.4(2)° (Hf). The structures of the ureato complexes 4aand 4b and the guanidino complex 7a exhibit typical alkoxido and amido bond distances (Zr−N = 2.1096(13) Å (4a), 2.137(3) Å (4b); Zr−O = 2.0677(12) Å (4a), 2.066(3) Å (4b); Hf−N = 2.087(2) Å, 2.151(2) Å (7a))

    Addition and Metathesis Reactions of Zirconium and Hafnium Imido Complexes

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    The zirconium and hafnium imido metalloporphyrin complexes (TTP)MNAriPr (TTP = meso-5,10,15,20-tetra-p-tolylporphyrinato dianion; M = Zr (1), Hf; AriPr = 2,6-diisopropylphenyl) were used to mediate addition reactions of carbonyl species and metathesis of nitroso compounds. The imido complexes react in a stepwise manner in the presence of 2 equiv of pinacolone to form the enediolate products (TTP)M[OC(tBu)CHC(tBu)(Me)O] (M = Zr (2), Hf (3)), with elimination of H2NAriPr. The bis(μ-oxo) complex [(TTP)ZrO]2 (4) is formed upon reaction of (TTP)ZrNAriPr with PhNO. Treatment of compound 4 with water or treatment of compound 2 with acetone produced the (μ-oxo)bis(μ-hydroxo)-bridged dimer [(TTP)Zr]2(μ-O)(μ-OH)2 (5). Compounds 2, 4, and 5 were structurally characterized by single-crystal X-ray diffraction

    Manufacturability verification through feature-based ontological product models

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    To achieve efficient, fast and cost effective production, designers must consider all the manufacturing stages a product has to go through. A case study in a manufacturing setup shows that owing to the differences in perception of an engineering component, the coordination between design and manufacturing becomes difficult. Semantic interoperability problems are therefore faced when knowledge sharing for the purpose of manufacturability verification is attempted through computer-based knowledge bases. Ontologies have a reputation for solving semantic interoperability problems. Combined with shape feature-based models of components, ontologies provide a basis for seamless knowledge sharing. This article demonstrates the use of ontologies for analyzing the manufacturability of engineering components in the early design stages. This is done by developing shape feature-based ontological models of these components and associating manufacturability knowledge with these models. To achieve this, an ontological modelling technique is proposed that uses shape feature-based geometrical models of engineering components as building blocks. The knowledge associated with these models to demonstrate their use for manufacturability verification is derived from the findings of a case study also detailed in this article. © IMechE 2012

    Mediation of foundation ontology based knowledge sources

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    Ontologies are helpful in giving interoperable structures to sources of knowledge and information. This interoperability, however, is greatly hindered by the heterogeneity of independently developed ontologies which in turn increases the requirements for mediation systems to reconcile the differences. A core concepts ontology for a certain domain contained by a foundation ontology can be used to alleviate this problem and to facilitate the reconciliation efforts. Possible differences in the use of concepts from the core concepts to model entities in domain ontologies can be prevented by binding the domain ontology developers to some rules. These rules can be particularly useful for domain ontologies requiring some kind of traceability of their concepts in the foundation ontology. The mediation system can then use this traceability to establish similarities between two ontologies. Software applications, like the one explained in this paper, can then be developed to perform the mediation task automatically and accurately

    Gap analysis of ontology mapping tools and techniques

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    Mapping between ontologies provides a way to overcome any dissimilarities in the terminologies used in two ontologies. Some tools and techniques to map ontologies are available with some semi-automatic mapping capabilities. These tools are employed to join the similar concepts in two ontologies and overcome the possible mismatches.Several types of mismatches have been identified by researchers and certain overlaps can easily be seen in their description. Analysis of the mapping tools and techniques through a mismatches framework reveals that most of the tools and techniques just target the explication side of the concepts in ontologies and a very few of them opt for the conceptualization mismatches. Research therefore needs to be done in the area of detecting and overcoming conceptualization mismatches that may occur during the process of mapping. The automation and reliability of these tools are important because they directly affect the interoperatbility between different knowledge sources
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