71 research outputs found

    PEER Testbed Study on a Laboratory Building: Exercising Seismic Performance Assessment

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    From 2002 to 2004 (years five and six of a ten-year funding cycle), the PEER Center organized the majority of its research around six testbeds. Two buildings and two bridges, a campus, and a transportation network were selected as case studies to “exercise” the PEER performance-based earthquake engineering methodology. All projects involved interdisciplinary teams of researchers, each producing data to be used by other colleagues in their research. The testbeds demonstrated that it is possible to create the data necessary to populate the PEER performancebased framing equation, linking the hazard analysis, the structural analysis, the development of damage measures, loss analysis, and decision variables. This report describes one of the building testbeds—the UC Science Building. The project was chosen to focus attention on the consequences of losses of laboratory contents, particularly downtime. The UC Science testbed evaluated the earthquake hazard and the structural performance of a well-designed recently built reinforced concrete laboratory building using the OpenSees platform. Researchers conducted shake table tests on samples of critical laboratory contents in order to develop fragility curves used to analyze the probability of losses based on equipment failure. The UC Science testbed undertook an extreme case in performance assessment—linking performance of contents to operational failure. The research shows the interdependence of building structure, systems, and contents in performance assessment, and highlights where further research is needed. The Executive Summary provides a short description of the overall testbed research program, while the main body of the report includes summary chapters from individual researchers. More extensive research reports are cited in the reference section of each chapter

    The Risk of Obstetric Complications and the Effects of Treatment in Women with Low Titer and Medium-High Titer Anti-Phospholipid Antibodies

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    Background/Purpose: The association of low titer anti-phospholipid antibodies (aPL) with obstetric anti-phospholipid syndrome (APS) is increasingly acknowledged, even though some studies have showed conflicting results. To raise further evidence on the relevance of low titer aPL in pregnancy morbidity (PM), we retrospectively reviewed the clinical records of pregnant women attending a joint obstetric/rheumatology clinic over the years 2009-2016. Methods: Patients were included when positive in at least one criteria aPL assay, at any titer, in two occasions minimum 12 weeks apart. Statistical analysis was performed using R package. Results: 111 women (338 pregnancies) were identified. 51 women displayed low-titer aPL, with 160 pregnancies. 60 patients carried aPL at medium-high titers, with 178 pregnancies. 4 patients (4%) had thrombotic APS, 27 (24%) obstetric APS, 7 (6%) thrombotic and obstetric APS, 15 (14%) medium-high titer aPL and non criteria PM, 7 (6%) medium-high titer aPL and no PM, 18 (16%) low titer aPL and non criteria PM and 15 (14%) low titer aPL and no PM. Low-titer aPL were significantly associated with pregnancy complications (c2=8.82, p=0.003). Considering 245 untreated pregnancies, a significant difference in PM distribution was noted for low titer and medium-high titer aPL (p=0.003, Table 1). Among patients with low titer aPL, treatment with low molecular weight heparin [LMWH] + low-dose aspirin [LDASA] significantly improved pregnancy outcomes (p<<0.001, odds ratio [OR]=0.07, 95% CI=0.007\u20130.300), leading to a 14.3-fold reduction of obstetric complications. Hydroxychloroquine [HCQ] was not associated with a significant improvement in live birth rate (p=0.079). Among women with medium-high titer aPL, the standard therapeutic approach with LMWH+LDASA resulted in a significant improvement of obstetric outcome (p<<0.001, OR=0.20, 95% CI=0.100\u20130.400). HCQ treatment significantly improved obstetric outcome, carrying a 3-fold increase in the live birth rate (p=0.025, OR=0.34, 95% CI=0.117\u20130.894). Conclusion: According to our data, low titer aPL are significantly associated with aPL-associated obstetric complications, with a lower prevalence of premature birth compared to medium-high titer aPL. Treatment with LDASA+LMWH led to a higher increase of live birth rate in women with low titer aPL compared to those with medium-high titer aPL. Additional treatment such as HCQ were effective in women with medium-high titer aPL but not those with low titer aPL. Table 1. Obstetric outcomes (defined according to Miyakis et al, 2006) in 245 untreated pregnancies in women with low titer and medium-high titer anti-phospholipid antibodies

    Minerales con hierro en arcillas vinculadas a la ingresión marina holocena en la llanura costera del estuario del Río de la Plata (Argentina): implicancias paleoambientales

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    En este trabajo se efectúa la caracterización de los minerales portadores de hierro en arcillas de la llanura costera del estuario del Río de la Plata, incluidas en la Facies Villa Elisa de la Formación Las Escobas (MIS1), con el principal objetivo de contribuir a su interpretación paleoambiental. Además, los resultados permi­ ten hacer inferencias que se estiman de interés para la Pedología y para las Ciencias Ambientales. El trabajo abarca el uso de diversas técnicas (análisis quí­ micos, determinación de propiedades magnéticas, análisis térmico diferencial­ termogravimétrico, difractometría de rayos X y espectroscopia Mössbauer). Los materiales analizados presentan tonalidades gris­oliva y se clasifican como arcillas. Presentan una asociación mineralógica compleja, resultado de la combinación de múltiples factores, que incluyen procesos vinculados a su procedencia, al ambiente de depositación y a los efectos de la pedogénesis. Dominan los argilominerales (aproximadamente 60%), representados principalmente por esmectitas, illita y secundariamente por caolinita e interestratificados illita/esmectita con elevado contenido de capas expansivas. Se identificó también la presencia de cuarzo, plagio­ clasas, feldespatos alcalinos y en menor medida calcita y óxi­hidróxidos de hierro. El contenido de hierro total es considerable (alrededor del 10%), con un claro pre­ dominio de Fe3+ sobre el Fe2+ (92% y 8%, respectivamente). Los óxi­hidróxidos de hierro presentes (goethita y eventualmente ferrihidrita) no constituyen los principales portadores de hierro. De esta manera se concluye que el Fe3+ se en­ cuentra principalmente en los argilominerales, en particular en esmectitas ricas en hierro (Fe­esmectitas), del tipo nontronita/Fe­beidellita. La asociación mineral determinada tiene importantes implicancias para la interpretación paleoambiental. Se concluye que un ambiente de marisma recibió argilominerales a partir de la erosión de suelos loéssicos (principalmente esmectitas e illita) y por corrientes mareales (más ricos en esmectitas y caolinita). Mecanismos propios del ambiente depositacional, vinculados a ciclos de humedecimiento­secado con oscilaciones de Eh en un medio levemente alcalino permitieron la incorporación de hierro en la estructura de las esmectitas. Un aspecto a destacar es que estos materiales pre­ sentan colores glei originados por minerales con Fe3+ (Fe­esmectitas y goethita), lo cual contradice el tradicional supuesto en Pedología, que asocia este patrón de color a minerales de Fe2+. Finalmente, se destaca que la elevada participación de Fe­esmectitas en asociación con óxi­hidróxidos de hierro, contribuye a la adsorción de metales pesados y otros contaminantes de la región, dándole a la Facies Villa Elisa un importante valor ambiental

    Antibodies Against Domain 1 and Domain 4/5 of &#946;2 Glycoprotein I : Clinical Relevance in Obstetric Anti-Phospholipid Syndrome

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    Background/Purpose: The domain reactivity of antibodies against b2 glycoprotein I (anti-b2GPI) has been investigated in patients with thrombotic anti-phospholipid syndrome (APS), leading to the identification of antibodies targeting domain 1 of the molecule (anti-D1) as the most relevant autoantibody subpopulation. Scarce attention has been paid to the domain profiling of patients with pregnancy morbidity (PM). The aim of this study was to characterize the relevance of the fine epitope reactivity of anti-b2GPI antibodies in anti-phospholipid antibody (aPL)-associated PM. Methods: Women with persistent positivity for anti-b2GPI IgG antibodies at medium-high titers, with at least one pregnancy and without systemic autoimmune disease were included. Anti-D1 and anti-D4/5 antibodies were tested using a chemiluminescent immunoassay and a research ELISA assay, respectively (QUANTA Flash b2GPI IgG and QUANTA Lite, Inova Diagnostics). Statistical analysis was performed using R package. Results: 138 women fulfilling the inclusion criteria were retrospectively recruited at 3 referral centres. 49 patients (35%) had obstetric APS, 18 (13%) thrombotic APS, 37 (27%) thrombotic and obstetric APS while 34 women (25%) were asymptomatic aPL carriers. 81 women (60%) displayed triple aPL positivity, 32 (23%) had two positive aPL test and 23 (17%) carried a single aPL positivity. 110 patients had at least one untreated pregnancy, culminating in a live birth in 31 cases (28%). 89 women underwent a pregnancy course while receiving treatment, with 71 women (80%) having a live birth. A significant difference in the distribution of positive anti-D1 antibodies emerged between women with or without PM and with or without thrombosis (p=0.05, c2=2.710 and p<0.001, c2=12.174, respectively); no significant difference was observed for anti-D4/5 antibodies (Table 1). In a multivariate logistic regression model also encompassing treatment, positive anti-D1 antibodies, but not anti-D4/5, were significantly associated with obstetric complications, conferring an odds ratio (OR) of 2.32 (p=0.040 and p=0.724, respectively). Triple aPL positivity corrected by treatment significantly predicted PM (p=0.015, OR=2.78). Conclusion: Our data suggest that anti-D1 antibodies are significantly associated not only with thrombosis but also with obstetric morbidity while positive anti-D4/5 antibodies are not predictive of PM

    A tetracationic porphyrin with dual anti-prion activity

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    Prions are deadly infectious agents made of PrPSc, a misfolded variant of the cellular prion protein (PrPC) which self-propagates by inducing misfolding of native PrPC. PrPSc can adopt different pathogenic conformations (prion strains), which can be resistant to potential drugs, or acquire drug resistance, hampering the development of effective therapies. We identified Zn(II)-BnPyP, a tetracationic porphyrin that binds to distinct domains of native PrPC, eliciting a dual anti-prion effect. Zn(II)-BnPyP binding to a C-terminal pocket destabilizes the native PrPC fold, hindering conversion to PrPSc; Zn(II)-BnPyP binding to the flexible N-terminal tail disrupts N- to C-terminal interactions, triggering PrPC endocytosis and lysosomal degradation, thus reducing the substrate for PrPSc generation. Zn(II)-BnPyP inhibits propagation of different prion strains in&nbsp;vitro,&nbsp;in neuronal cells and organotypic brain cultures. These results identify a PrPC-targeting compound with an unprecedented dual mechanism of action which might be exploited to achieve anti-prion effects without engendering drug resistance

    Seismic Protection of Laboratory Contents: The UC Berkeley Science Building Case Study

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    The research described in this report is a part of the Disaster Resistant University (DRU) initiative funded by the Federal Emergency Management Agency (FEMA) and the University of California, Berkeley. The first phase of the Disaster Resistant University initiative produced a study of potential earthquake losses at UC Berkeley together with an analysis of the economic impacts. In that report, Comerio (2000) found that despite the extraordinary building retrofit program, the UC Berkeley campus remained vulnerable to losses from nonstructural failures and losses in highly concentrated research facilities.This report is focused on strategies for improving seismic performance for laboratory furnishings and equipment. The report describes a case study of a biology laboratory building and its contents, used as a basis for developing damage mitigation strategies and cost estimates. The data developed here were also used by researchers at the Pacific Earthquake Engineering Research (PEER) Center for the development of loss estimates and for the development of models for performance-based engineering (UC Science Testbed Committee, 2002), as well as for a technical manual on retrofitting laboratory contents (Holmes and Comerio, 2003)
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