269 research outputs found
Erskine Street Interchange
Erskine Street Interchange is a new roadway interchange constructed in Brooklyn, New York in 2002. Challenges addressed in construction of the interchange included poor foundation conditions, such as the presence of hydraulic sand fill, a weak cohesive deposit, an approximately 30-year old municipal waste landfill beneath portions of the abutment ramps, and the presence of one of the most important commuter roadways in Brooklyn and Queens, the Belt Parkway, immediately adjacent to the construction site. How these challenges are addressed in the final design and construction of the Erskine Street Interchange will be discussed. The design consists of on grade ramps approaching a pile supported abutment. A ground improvement program, including deep dynamic compact, soil surcharge and use of geogrids was implemented. The quality control measures used to verify soil performance and protect the adjacent parkway, and long term monitoring and performance of the embankments will also be addressed
Robust, Flexible Motion Control for the Mars Explorer Rovers
The Mobility Flight Software, running on computers aboard the Mars Explorer Rover (MER) robotic vehicles Spirit and Opportunity, affords the robustness and flexibility of control to enable safe and effective operation of these vehicles in traversing natural terrain. It can make the vehicles perform specific maneuvers commanded from Earth, and/or can autonomously administer multiple aspects of mobility, including choice of motion, measurement of actual motion, and even selection of targets to be approached. Motion of a vehicle can be commanded by use of multiple layers of control, ranging from motor control at a low level, direct drive operations (e.g., motion along a circular arc, motion along a straight line, or turn in place) at an intermediate level to goal-position driving (that is, driving to a specified location) at a high level. The software can also perform high-level assessment of terrain and selection of safe paths across the terrain: this involves processing of the digital equivalent of a local traversability map generated from images acquired by stereoscopic pairs of cameras aboard the vehicles. Other functions of the software include interacting with the rest of the MER flight software and performing safety checks
Reuters Comes to Times Square
Times Square in New York City was chosen for the new Reuters Headquarters Building for its significance as the crossroads of the world. The headquarters consists of a 30-story office tower with a foundation footprint of 30,000 square feet including two subsurface levels nearly 40 feet deep for retail shops, parking and access to the Times Square subway station. This paper describes the geotechnical challenges that were faced to minimize the effects of both the construction excavation, mainly in mica schist rock, and a new permanent structure on two adjacent landmark theatres, the subway structures, and the streets and utilities of Times Square. Additionally, there could be no interruption of theatre performances or subway service. Engineering solutions included:
1. Supporting the subway structures during construction with a combination of a sand bag, wale and raker system.
2. Maximizing the underground tower space by creating a sidewalk vault.
3. Supporting and protecting two landmark theatres by sequencing the support with several tiers of rock anchors.
4. Supporting both theatre foundation walls and the “re-entry” corner of the New Victory Theatre by chipping the bedrock and carefully supporting what remained on the perimeter. Monitoring equipment was installed in the theatres for immediate notification of any movement and/or high vibrations
A High-Throughput Solid-Phase Microplate Protein-Binding Assay to Investigate Interactions between Myofilament Proteins
To understand the structure-function relationship of muscle-regulatory-protein isoforms, mutations, and posttranslational modifications, it is necessary to probe functional effects at the level of the protein-protein interaction. Traditional methodologies assessing such protein-protein interactions are laborious and require significant amounts of purified protein, while many current methodologies require costly and specialized equipment or modification of the proteins, which may affect their interaction. To address these issues, we developed a novel method of microplate-based solid-phase protein-binding assay over the recent years. This method assesses specific protein-protein interactions at physiological conditions, utilizes relatively small amounts of protein, is free of protein modification, and does not require specialized instrumentation. Here we present detailed methodology for the solid-phase protein-binding assay with examples that we have successfully applied to quantify interactions of myofilament-regulatory proteins. We further provide considerations for optimization of the assay conditions and its broader application in studies of other protein-protein interactions
A Study of Functional Recovery and Axonal Plasticity Following TBI and Anti-Nogo-A Immunotherapy
Traumatic brain injury (TBI) is a leading cause of morbidity and mortality globally and often results in long term disability. Unfortunately, the success of rehabilitation techniques as therapy for TBI is limited, which may be due to the growth restrictive environment of the adult central nervous system (CNS). This environment is thought to result from glial scars, lack of neurotrophic factors, and the presence of an array of growth-inhibitory molecules. One such growth-inhibitory molecule is the protein Nogo-A. Our laboratory has shown that neutralization of Nogo-A with anti-Nogo-A immunotherapy after ischemic stroke results in improvement in functional recovery in the skilled forelimb reaching task and is correlated with an increase in axonal plasticity. In the present study, we sought to determine whether anti-Nogo-A immunotherapy following TBI produces similar recovery as with ischemic stroke. Therefore, we hypothesized that anti-Nogo-A immunotherapy following TBI in the adult rat will result in enhanced axonal plasticity and improved recovery of motor function. Accordingly, adult rats were trained in the skilled forelimb reaching task and received either a TBI via controlled cortical impact (CCI) or no TBI. One week later, rats that received a TBI were administered anti-Nogo-A antibody (11C7), control antibody, or no treatment and tested for seven more weeks on the skilled forelimb reaching task to assess functional recovery. Once behavioral testing was completed, an anterograde neuroanatomical tracer was injected into the sensorimotor cortex contralateral to the TBI lesion to assess axonal plasticity. Behavioral analysis did not demonstrate whether or not there was recovery of skilled forelimb function since control animals significantly recovered by week two and almost fully by the end of the study. Subsequent neuroanatomical analysis revealed no increased neuroplasticity at the level of the red nucleus in animals treated with mAB 11C7 at week eight post-TBI. To determine if anti-Nogo-A antibodies increase functional recovery and axonal plasticity following TBI, future studies should aim to produce TBI lesions that induce lasting deficits
Rion – Antirion Bridge Foundations: A Blend of Design and Construction Innovation
This case history discusses the design and construction of the appropriate foundation scheme for the largest cable-stayed bridge in the world. This concession project was financed through a combination of public funds, private equity and bank loans. When completed in 2004, the Rion-Antirion Bridge will connect the Peloponnese, Greece’s southernmost peninsula, with the mainland across the Gulf of Corinth. Alternative foundation concepts that were considered included traditional driven piles, deeply embedded caissons, and soil improvement. The process of how the foundation evolved from schematics to final design, what were the driving forces, how ideas were disseminated among the Design Team, the Design Checker and the Technical Advisors, and the performance of the foundations to date are summarized
Re-engineering the Multimission Command System at the Jet Propulsion Laboratory
The Operations Engineering Lab (OEL) at JPL has developed the multimission command system as part of JPL's Advanced Multimission Operations System. The command system provides an advanced multimission environment for secure, concurrent commanding of multiple spacecraft. The command functions include real-time command generation, command translation and radiation, status reporting, some remote control of Deep Space Network antenna functions, and command file management. The mission-independent architecture has allowed easy adaptation to new flight projects and the system currently supports all JPL planetary missions (Voyager, Galileo, Magellan, Ulysses, Mars Pathfinder, and CASSINI). This paper will discuss the design and implementation of the command software, especially trade-offs and lessons learned from practical operational use. The lessons learned have resulted in a re-engineering of the command system, especially in its user interface and new automation capabilities. The redesign has allowed streamlining of command operations with significant improvements in productivity and ease of use. In addition, the new system has provided a command capability that works equally well for real-time operations and within a spacecraft testbed. This paper will also discuss new development work including a multimission command database toolkit, a universal command translator for sequencing and real-time commands, and incorporation of telecommand capabilities for new missions
Enhanced Reporting of Mars Exploration Rover Telemetry
Mars Exploration Rover Enhanced Telemetry Extraction and Reporting System (METERS) is software that generates a human-readable representation of the state of the mobility and arm-related systems of the Mars Exploration Rover (MER) vehicles on each Martian solar day (sol). Data are received from the MER spacecraft in multiple streams having various formats including text messages, sparsely-sampled engineering quantities, images, and individual motor-command histories
Staurosporine Inhibits Frequency-Dependent Myofilament Desensitization in Intact Rabbit Cardiac Trabeculae
Myofilament calcium sensitivity decreases with frequency in intact healthy rabbit trabeculae and associates with Troponin I and Myosin light chain-2 phosphorylation. We here tested whether serine-threonine kinase activity is primarily responsible for this frequency-dependent modulations of myofilament calcium sensitivity. Right ventricular trabeculae were isolated from New Zealand White rabbit hearts and iontophoretically loaded with bis-fura-2. Twitch force-calcium relationships and steady state force-calcium relationships were measured at frequencies of 1 and 4 Hz at 37 °C. Staurosporine (100 nM), a nonspecific serine-threonine kinase inhibitor, or vehicle (DMSO) was included in the superfusion solution before and during the contractures. Staurosporine had no frequency-dependent effect on force development, kinetics, calcium transient amplitude, or rate of calcium transient decline. The shift in the pCa50 of the force-calcium relationship was significant from 6.05 ± 0.04 at 1 Hz versus 5.88 ± 0.06 at 4 Hz under control conditions (vehicle, P < 0.001) but not in presence of staurosporine (5.89 ± 0.08 at 1 Hz versus 5.94 ± 0.07 at 4 Hz, P = NS). Phosphoprotein analysis (Pro-Q Diamond stain) confirmed that staurosporine significantly blunted the frequency-dependent phosphorylation at Troponin I and Myosin light chain-2. We conclude that frequency-dependent modulation of calcium sensitivity is mediated through a kinase-specific effect involving phosphorylation of myofilament proteins
Heart Failure in Humans Reduces Contractile Force in Myocardium from Both Ventricles
This study measured how heart failure affects the contractile properties of the human myocardium from the left and right ventricles. The data showed that maximum force and maximum power were reduced by approximately 30% in multicellular preparations from both ventricles, possibly because of ventricular remodeling (e.g., cellular disarray and/or excess fibrosis). Heart failure increased the calcium (Ca2+) sensitivity of contraction in both ventricles, but the effect was bigger in right ventricular samples. The changes in Ca2+ sensitivity were associated with ventricle-specific changes in the phosphorylation of troponin I, which indicated that adrenergic stimulation might induce different effects in the left and right ventricles
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