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Transportation agencies expend large amounts of money annually to maintain highway wearing surfaces. Wear depends mainly on axle weight, vehicle speed, temperature, surface type, and the type of tires mounted on vehicles. When studded tires are used, wear is increased significantly. Past studies on the use of studded tires have highlighted the need for a tool to better estimate the number of vehicles with studded tires that travel a road network. Currently, there is no such tool available. This paper presents a detection methodology using acoustic emission techniques to identify vehicles operating with studded tires. Data from an in-service test on a highway bridge were used for developing and evaluating two proposed detection schemes. It was found that using relatively simple detection algorithms, vehicles with studded tires could be discriminated reliably. Finally, a practicable integrated system is proposed that could be implemented for detection and monitoring of studded snow tire use on highway systems. DOI: 10.1061/(ASCE)TE.1943-5436.0000062 CE Database subject headings: Tires; Vehicles; Probe instruments; Monitoring; Bridges; Highway. Author keywords: Studded tires; Acoustic Emission; Monitoring; Real-time detection; Highway bridges.

Tests were performed on full-size prefabricated steel stair assemblies to assess seismic interstory drift response combined with factored gravity loads. The stair assemblies were production-run units of a standard system and were designed for a typical steel frame building. Two different stair assembly units were tested: one with checker plate and one with concrete-filled pans. A loading system and testing protocol were developed to evaluate the seismic performance using seismic and gravity load combinations. Lateral drifts were imposed in both orthogonal stair directions followed by factored live and dead gravity loads. Imposed lateral drift placed high deformation demands on the stair-to-landing connections and overall performance is dependent on the deformability and endurance of these connections. Careful detailing, fabrication, and inspection of the stair-to-landing connections are required to ensure desired system performance. DOI: 10.1061/(ASCE)0733-9445(2009)135:2(122) CE Database subject headings: Stairs; Seismic design; Seismic tests; Gravity loads; Combined loads.

A bridge rating application is developed using the Tool Command Language (Tel) scripting language in conjunction with the OpenSees finite-element software framework. Fully programmable and string based, Tel is ideal for implementing live load analysis through scripts and experimenting with emergent bridge rating methodologies. Since Tel is an interpreted language, the application also has the important advantage that new bridge capacity models and rating factor calculations can be implemented quickly by a user without compiling source code. The rating application is demonstrated on a conventionally reinforced concrete bridge girder. The use of OpenSees for finite-element analysis makes the rating application readily extensible to nonlinear structural response and advanced structural reliability methods for a variety of a bridge types and structural components. CE Database subject headings: Bridge maintenance; Computer aided simulation; Computer programming; Live loads; Ratings; Structural analysis.

Author(s): Christopher F. Higgins (corresponding author) [1, 2] The acquisition of multidrug resistance is a serious impediment to improved healthcare. Multidrug resistance is most frequently due to active transporters that [...]

Author(s): Christopher F. Higgins (corresponding author) [1, 2] The acquisition of multidrug resistance is a serious impediment to improved healthcare. Multidrug resistance is most frequently due to active transporters that [...]

Memory lymphocytes are important mediators of the immune response. These cells are long-lived and undergo clonal expansion upon reexposure to specific antigen, differentiating into effector cells that secrete Ig or cytokines while maintaining a residual pool of memory T and B lymphocytes. Here, the ability of antigen-specific lymphocytes to undergo repeated cycles of antigen-driven clonal expansion and contraction is exploited in a therapeutic protocol aimed at regulating protein delivery. The principle of this strategy is to introduce genes encoding proteins of therapeutic interest into a small number of antigen-specific B lymphocytes. Output of therapeutic protein can then be regulated in vivo by manipulating the size of the responder population by antigen challenge. To evaluate whether such an approach is feasible, we developed a mouse model system in which E[mu]- and Ig[lambda]-based vectors were used to express human erythropoietin (hEPO) gene in B lymphocytes. These mice were then immunized with the model antigen phycoerythrin (PE), and immune splenocytes (or purified PE-specific B lymphocytes) were adoptively transferred to normal or mutant (EPO-deficiency) hosts. High levels of hEPO were detected in the serum of adoptively transferred normal mice after PE administration, and this responsiveness was maintained for several months. Similarly, in EPO-deficient anemic recipients, antigen-driven hEPO expression was shown to restore hematocrit levels to normal. These results show that antigen-mediated regulation of memory lymphocytes can be used as a strategy for delivering therapeutic proteins in vivo.

Bacteria have developed antibiotic-resistance mechanisms, and LmrA, a protein in Lactococcus lactis, extrudes amphiphilic compounds from the cytoplasmic membrane, to mediate antibiotic resistance. LmrA is an ATP-binding cassette (ABC) transporter, along with the human multidrug-resistance P-glycoprotein. LmrA was expressed in human ling fibroblast cells, which was surprisingly targeted to the plasma membrane, conferring typical multi-drug resistance. Their pharmacological characteristics were similar and their affinity for vinblastine and magnesium-ATP was indistinguishable.

Enolase and RhlB, a member of the DEAD-box family of ATP-dependent RNA helicases, are novel components of RNA degradosome. RhlB most likely unwinds distinct RNA structures in the presence of ATP to facilitate mRNA degradation by PNPase as shown by the RNAs failure to degrade when RhlB is blocked by an affinity-purified antibody even if ATP is added. Enolase's purpose in degradosome is still unknown.

Specific protein-ligand interactions are critical for cellular function, and most proteins select their partners with sharp discrimination. However, the oligopeptide-binding protein of Salmonella typhimurium (Oppa) binds peptides of two to five amino acid residues without regard to sequence. The crystal structure of Oppa reveals a three-domain organization, unlike other periplasmic binding proteins. in Oppa-peptide complexes, the ligands are completely enclosed in the protein interior, a mode of binding that normally imposes tight specificity. The protein fulfills the hydrogen bonding and electrostatic potential of the ligand main chain and accommodates the peptide side chains in voluminous hydrated cavities., In bacteria, periplasmic substrate-binding proteins capture extracellular nutrients and deliver them to membrane-associated complexes that translocate the ligand across the inner membrane and into the cytoplasm[1]. Several periplasmic binding proteins [...]

There is a family of proteins that bind adenosine triphosphate (ATP), a molecule involved in the production of energy, which are also involved in the transport of molecules. This group of proteins includes molecules of bacteria involved in the uptake and export of molecules. In higher organisms, they include genes involved in resistance to multiple types of drugs used in tumor therapy; in resistance to the drug chloroquine in the malarial parasite; the transport of a yeast mating pheromone; and the gene that is defective in cystic fibrosis. Structural models are presented of these ATP-binding transport molecules. In almost 70 percent of the patients with cystic fibrosis, deletions are present in the areas of the gene that are involved in binding and degrading of ATP. Many of the symptoms of cystic fibrosis stem from abnormally thick secretions, especially in the lungs. These symptoms are related to a problem in the transport of chloride ions (electrically charged particles) across cellular membranes. Thus, it was thought that the defective gene in cystic fibrosis might encode a protein that works as a channel that ions pass through. However, some researchers believe that the defective protein in cystic fibrosis is not a channel for chloride molecules. Channels do not require the degradation of ATP. Chloride channels allow the flow of chloride ions in both directions, while the proteins that the gene involved in cystic fibrosis encodes only allow the flow of ions in one direction. Other evidence that indicates the gene does not code for a chloride channel includes: the size of the molecule, which is too large; chloride channels vary in different tissues, but there is only one defective gene in cystic fibrosis; and other characteristic sequences of chloride channels are not present. Therefore, it is thought that the protein is not a chloride channel, but may transport a molecule that regulates a chloride channel. (Consumer Summary produced by Reliance Medical Information, Inc.)

A cell must selectively translocate molecules across its plasma membrane to maintain the chemical composition of its cytoplasm distinct from that of the surrounding milieu. The most intriguing, and, arguably, [...]

The common bacterium Escherichia coli and its bacterial viruses are well used in science research because they have ideal pathogenic, and nutritional characteristics. However, the functions of up to 40% of an estimated 4,288 genes in E. coli have not yet been established. Scientists need to launch a cooperative international research strategy to ascertain the bacterium's genetic makeup.