Dilatometer Based Liquefaction Potential of Sites in the Imperial Valley

The liquefaction potential of several sites in the Imperial Valley, south California, is evaluated on the basis of standard penetration, cone, and dilatometer test data. The performance of the soil deposits at these sites during past earthquakes has been documented in earlier studies. Since the dilatometer parameter Kd is expected to reflect factors (e.g. fabric, prestress, preshaking, aging) affecting liquefaction potential to a certain extent (Marchetti, 1982), this paper primarily focuses on this parameter as an index for evaluating liquefaction potential. A tentative boundary curve (in terms of stress ratio vs. Kd) for evaluating liquefaction potential that takes advantage of earlier boundaries is proposed. A promising index which combines dynamic and static dilatometer tests is also proposed

Effective Stress Analyses of Seismic Stability

The factors involved in performing effective stress analysis of seismic stability problems are examined. The advantages of using a stochastic model for pore pressure generation are discussed. A simplified analysis of a hypothetical case is outlined to illustrate the factors involved in performing effective stress stability analysis

Structural Collapse Behavior of Sands in Undrained Shear

Results from undrained torsional shear tests are presented and used to further examine the concepts of steady state and structural collapse in sands, with emphasis on the influence of the collapse mechanism on soil behavior at steady state. It is shown that the degree to which the material collapses is dependent on the loading conditions and the initial fabric of the sand. Consequently, the steady state position in the state diagram is also function of these parameters

Performance of Fill Soils During the Loma Prieta Earthquake

The results of high quality in situ test results obtained at Hunter\u27s Point Naval Station both before and after the Lorna Prieta earthquake are presented. The interpretation of these tests and the results of subsequent numerical ground motion analyses are validated by the observed response at that site during the event. Data show that densification of the loose fill soils occurred as a result of the seismic activity and corroborate the observed surface deformations

Molecular and Electrophysiological Characterization of GFP-Expressing CA1 Interneurons in GAD65-GFP Mice

The use of transgenic mice in which subtypes of neurons are labeled with a fluorescent protein has greatly facilitated modern neuroscience research. GAD65-GFP mice, which have GABAergic interneurons labeled with GFP, are widely used in many research laboratories, although the properties of the labeled cells have not been studied in detail. Here we investigate these cells in the hippocampal area CA1 and show that they constitute ∼20% of interneurons in this area. The majority of them expresses either reelin (70±2%) or vasoactive intestinal peptide (VIP; 15±2%), while expression of parvalbumin and somatostatin is virtually absent. This strongly suggests they originate from the caudal, and not the medial, ganglionic eminence. GFP-labeled interneurons can be subdivided according to the (partially overlapping) expression of neuropeptide Y (42±3%), cholecystokinin (25±3%), calbindin (20±2%) or calretinin (20±2%). Most of these subtypes (with the exception of calretinin-expressing interneurons) target the dendrites of CA1 pyramidal cells. GFP-labeled interneurons mostly show delayed onset of firing around threshold, and regular firing with moderate frequency adaptation at more depolarized potentials

Molecular Characterization of a Novel Intracellular ADP-Ribosyl Cyclase

Background. ADP-ribosyl cyclases are remarkable enzymes capable of catalyzing multiple reactions including the synthesis of the novel and potent intracellular calcium mobilizing messengers, cyclic ADP-ribose and NAADP. Not all ADP-ribosyl cyclases however have been characterized at the molecular level. Moreover, those that have are located predominately at the outer cell surface and thus away from their cytosolic substrates. Methodology/Principal Findings. Here we report the molecular cloning of a novel expanded family of ADP-ribosyl cyclases from the sea urchin, an extensively used model organism for the study of inositol trisphosphate-independent calcium mobilization. We provide evidence that one of the isoforms (SpARC1) is a soluble protein that is targeted exclusively to the endoplasmic reticulum lumen when heterologously expressed. Catalytic activity of the recombinant protein was readily demonstrable in crude cell homogenates, even under conditions where luminal continuity was maintained. Conclusions/Significance. Our data reveal a new intracellular location for ADP-ribosyl cyclases and suggest that production of calcium mobilizing messengers may be compartmentalized