173 research outputs found
Recent Advances in Non-Linear Site Response Analysis
Studies of earthquakes over the last 50 years and the examination of dynamic soil behavior reveal that soil behavior is highly nonlinear and hysteretic even at small strains. Non-linear behavior of soils during a seismic event has a predominant role in current site response analysis. The pioneering work of H. B. Seed and I. M. Idriss during the late 1960âs introduced modern site response analysis techniques. Since then significant efforts have been made to more accurately represent the non-linear behavior of soils during earthquake loading. This paper reviews recent advances in the field of non-linear site response analysis with a focus on 1-D site response analysis commonly used in engineering practice. The paper describes developments of material models for both total and effective stress considerations as well as the challenges of capturing the measured small and large strain damping within these models. Finally, inverse analysis approaches are reviewed in which measurements from vertical arrays are employed to improve material models. This includes parametric and non-parametric system identification approaches as well as the use of Self Learning Simulations to extract the underlying dynamic soil behavior unconstrained by prior assumptions of soil behavior
Using Tactile Pressure Sensors to Measure Lateral Spreading Induced Earth Pressures Against a Large, Rigid Foundation
Two centrifuge tests were performed at the NEES facility at Rensselaer Polytechnic Institute (RPI) to observe lateral earth pressures mobilized against a rigid foundation element during liquefaction-induced lateral spreading, as part of a larger NEESR study aimed at developing novel approaches to mitigate the effects of seismically-induced ground failures on large, rigid foundation elements. Models were constructed in a laminar box to allow unimpeded downslope soil displacement, and the sand in the model was liquefied during the centrifuge test. Lateral pressures prior to, during, and after shaking and liquefaction were directly measured using a novel device: tactile pressure sensors. Prior to testing the production models, several 1g and centrifuge experiments were conducted to determine whether the tactile pressure sensors would accurately measure pressures. Using the tactile pressure sensor and configuration described in this paper, geostatic pressures measured prior to the shaking agreed well with the anticipated theoretical at-rest earth pressures. In this paper, we describe these initial tests, the challenges that were encountered, methods employed to overcome these challenges, and the production centrifuge tests
Progesterone utility in the synthesis of steroidal heterocyclic compounds with antitumor activity
Oneâpot and efficient method for the synthesis of progesteronpyridine 5a-c, 6a-c and 7a,b and/or progesteronpyran derivatives 9a-c and 10a,b by condensation reaction of progesterone 1 with different aldehydes and active methylene compounds in the presence of ammonium acetate or piperidine. New progesteronopyrimidine derivatives 12a-d and 13a, b were synthesized via interaction of progesterone 1 with urea or thiourea and/or guanidine reagents and aldehyde. Progesterone 1 was examined to synthesize heterocyclic compound 16 containing ?-Lactone chiral carbon via the reaction of hydrazone derivative 14 with phenyl isothiocyanate followed by boiling with chloroacetic acid in benzene. The biological activity of compounds 5a, 5b, 6b, 7a, 9b, 9c, 12a, 12c, and 13a were evaluated as growth inhibitors of the liver and the breast carcinoma human cell line (HEPG2 & MCF7). Compounds 13a, 12a and 7a showed a higher potency than the standard. Key Words: Progesterone, MCRâs (multicomponents reaction), (pyridine, pyran, pyrimidine, ?-Lactone) derivatives, HEPG2 & MCF7
Protective effects of some fruit juices with low-fat diet on rat testis damaged by carbon tetrachloride: A genetic and histological study
Oxidative stress, free radical, lipid peroxidation and antioxidant have become a common expression with most disease and methods for protection. Carbon tetrachloride (CCl4) is an industrial solvent which has destructive effects on a cell while most fruit juices have antioxidant effects. The aim of this study was to investigate the protective role of fruit juice on testis after toxic effect with CCl4 through oxidative stress with basal diet and low-fat diet. Seventy-five male albino rats were used for this study in which the juices of three fresh fruit, yellow apples (Malus domestica, L.), red grapes containing seeds (Vitis vinifera, L.) and pomegranates (Punica granatum, L.) were used as therapeutic agents. Histological sections of testis indicated that low-fat diet has obvious effects than basal diet in both the low-fat diet with CCl4 "LdC""con++", LdC with grape juice 2 ml "grpL2", LdC with pomegranate juice 2 ml "pomL2" and hyper effect in LdC with pomegranate juice 4 ml "pomL4" while it was equal in effect with basal diet in the other treatments. Low-fat diet gave significant effects (about 75% recovery in con++, LdC with Apple juice 2 ml and 4 ml "appL2, appL4" , LdC with grape juice 4 ml "grpL4" and pomL2) while 25% began to recover as shown in basal diet with pomegranate juice 4 ml "pomB4" and grpL2. Treatment of rats with pomegranate juice ameliorated the toxic effects of CCl4 with low-fat diet on Semi-random RAPD-DNA profile. Low-fat diet with fruit juice had positive effect against toxicity induced by CCl4 in testes of rats on the level of histological and DNA-RAPD studies.Key words: CCl4, rat testis, yellow apples, red grapes, pomegranates, low-fat diet, oxidative stress
Maternal DNA Methylation Regulates Early Trophoblast Development
This work was funded by the BBSRC, Wellcome Trust, MRC, the EC Network of Excellence EpiGeneSys, the EC BLUEPRINT project, the Centre for Trophoblast Research, and CIHR (grant MOP-119357 to L.L.). M.R.B. is a Sir Henry Dale Fellow (101225/Z/13/Z), jointly funded by the Wellcome Trust and the Royal Society
The EYA Tyrosine Phosphatase Activity Is Pro-Angiogenic and Is Inhibited by Benzbromarone
Eyes Absents (EYA) are multifunctional proteins best known for their role in organogenesis. There is accumulating evidence that overexpression of EYAs in breast and ovarian cancers, and in malignant peripheral nerve sheath tumors, correlates with tumor growth and increased metastasis. The EYA protein is both a transcriptional activator and a tyrosine phosphatase, and the tyrosine phosphatase activity promotes single cell motility of mammary epithelial cells. Since EYAs are expressed in vascular endothelial cells and cell motility is a critical feature of angiogenesis we investigated the role of EYAs in this process. Using RNA interference techniques we show that EYA3 depletion in human umbilical vein endothelial cells inhibits transwell migration as well as Matrigel-induced tube formation. To specifically query the role of the EYA tyrosine phosphatase activity we employed a chemical biology approach. Through an experimental screen the uricosuric agents Benzbromarone and Benzarone were found to be potent EYA inhibitors, and Benzarone in particular exhibited selectivity towards EYA versus a representative classical protein tyrosine phosphatase, PTP1B. These compounds inhibit the motility of mammary epithelial cells over-expressing EYA2 as well as the motility of endothelial cells. Furthermore, they attenuate tubulogenesis in matrigel and sprouting angiogenesis in the ex vivo aortic ring assay in a dose-dependent fashion. The anti-angiogenic effect of the inhibitors was also demonstrated in vivo, as treatment of zebrafish embryos led to significant and dose-dependent defects in the developing vasculature. Taken together our results demonstrate that the EYA tyrosine phosphatase activity is pro-angiogenic and that Benzbromarone and Benzarone are attractive candidates for repurposing as drugs for the treatment of cancer metastasis, tumor angiogenesis, and vasculopathies
Sertraline plus deanxit to treat patients with depression and anxiety in chronic somatic diseases: a randomized controlled trial
Risk of bleeding after hospitalization for a serious coronary event: a retrospective cohort study with nested case-control analyses
The Maule (Chile) Earthquake of February 27, 2010: Consequence Assessment and Case Studies
On February 27, 2010 at 03:34 am local time, a powerful earthquake of
magnitude 8.8 struck central Chile. The epicenter of the earthquake was
approximately 8 km off the central region of the Chilean coast. With an inclined
rupture area of more than 80,000 square km that extends onshore, the region of
Maule was subjected to a direct hit, with intense shaking of duration of at least
100 seconds, and peak horizontal and vertical ground acceleration of over 0.6
g. The earthquake caused the death of 521 persons, with almost half of the
fatalities caused by the consequential tsunami. Over 800,000 individuals were
directly affected through death, injury and displacement. More than a third of a
million buildings were damaged to varying degrees, including several cases of
total collapse of major structures. The transportation system was dealt a
crippling blow, with 830 failures registered with the Ministry of Public Works on
roads in both the public and private transportation networks. Disruption of
commerce as well as the rescue and response effort resulted from the damage
to roads, embankments and bridges. On the whole, the performance of
engineered structures was reasonable, taking into account the magnitude and
proximity of the earthquake. The latter conclusion is supported by the
observations from several back-analyses presented in this report. Damage to
non-engineered construction is as expected in major earthquakes. Most
reinforced concrete bridges behaved well.
The role of social networking tools in enabling the affected population to
communicate was a most interesting feature in the response to this
earthquake. Due to the failure of the power grid, and the congestion of the
cellphone network, the population resorted to short message service and web
social media. Ham radio networks were activated to fill gaps due to the failure
of the radio network in places. The failure in ham radio broadcast in coastal
regions might have increased the fatalities because tsunami warning did not
reach all hazardous locations.
The MAE Center field reconnaissance team members consider that Chilean
engineering was proven to be robust and that seismic design provisions and
construction practices are of high standard. The extensive damage from this
Mw = 8.8 earthquake is expected and within the ???life safety??? performance target
of seismic design codes.National Science Foundation EEC-9701785unpublishednot peer reviewe
- âŠ