bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermodynamic Evaluation of Combined Cycle Using Different Methods of Steam Cooling
Authors: Sanjay  , Singh Onkar , Prasad B. N.
Published: November 2008

This paper deals with comparative study of the influence of different methods of steam cooling on the performance of simple combined gas/steam cycle plants. The topping cycle chosen is simple gas turbine while the bottoming cycle is a triple-pressure reheat steam cycle. Steam has been chosen as the cooling medium to be studied, as it is the most promising medium. All possible open and closed loop cooling with steam as the cooling medium have been considered. The prediction is based on the modeling of various elements of simple combined gas/steam cycle considering the real situation. The study shows that closed loop steam cooling is superior as compared to other steam cooling methods. However even though other two methods are slightly inferior technologically, but they do not suffer from the chances of problems of cogging of coolant holes if the steam is not ultra pure.
Increasing Steam Turbine Capacity
Authors: Cioffi Deborah H.
Published: November 2008

Steam turbine owners are often searching for opportunities to increase power output. Increases in steam turbine flow capacity yield a proportional increase in power output, but there is more to increasing capacity than just opening up nozzle areas. This paper describes how Mechanical Dynamics and Analysis personnel increased the flow capacity and power output using original blading on a large, supercritical, reheat unit while maintaining a high level of efficiency. Much attention was given to the as-left stage properties in order to minimize the change in efficiency from the design levels. The work is documented using a timeline which centers on the outage. Much of the engineering work done prior to the outage minimized the time necessary during the outage to complete the modifications. Before and after test results demonstrate the cost-benefit of the capacity increase.
A New Approach for Investigation of the Turbine Generator Oscillatory Behavior Affecting Power System Quality and Reliability
Authors: Kumar Rajiv , Merkle Michael , Leibfried Thomas
Published: November 2008

Transients following switching in the network and/or the tripping of generating unit auxiliaries can excite oscillatory torques on the turbine-generator-rotor-shaft system. The oscillations can be damped or amplified with time. Damped oscillations affect the power quality and if the oscillations grow with time they may even lead to generating unit outages (and damages) resulting in possible system instabilities. Deregulation of electricity markets has resulted in separation of Utility Companies (responsible for power generation) and Transmission Companies (responsible for power transmission). The decision making is no more under the same umbrella. Companies on both the sides have severe cost reduction focus and each side is tempted to make independent decision favourable to it. The Transmission Companies want to enhance transmission capacity of existing systems by introducing measures like series capacitor compensation. However incorporation of series capacitor compensation may under certain conditions lead to oscillations and also snbsynchronous resonance. Currently, there is an urgent need to establish a systematic methodology to investigate the root cause of such oscillations so that preventive measures can be taken by both the Utility Companies and the Transmission Companies. This paper is a contribution in this direction. In this work, comprehensive dynamic model of synchronous generator system has been developed in software Matlab/Simulink. Generating unit start up and ramp loading to rated load has been simulated to get deeper insight into the oscillatory behaviour of the synchronous generator. Block loading of the turbine generator and sudden load shedding due to auxiliary trip have been investigated in detail. Further, power system network with bus connected parallel generating units and parallel transmission lines, having different series capacitor compensation ratio have been simulated in power system software NETOMAC. Transient conditions have been modelled to investigate the oscillations and the consequent torsional torques and angles between adjacent masses of the rotor shaft system causing fatigue life reduction. This work has very clearly revealed the complex dynamic interrelationship among variables responsible for power system oscillations.
NOX Control Systems: SCR Bypass Systems — 20,000 MW of Case Studies
Authors: Brotzman John M.
Published: November 2008

Correct design and layout of the SCR BYPASS SYSTEM is critically important to the efficiency and operation of power plants. Utilities have even had to consider closing down plants that could not efficiently operate their Bypass Systems. Numerous gas path configurations are available, which vary considerably based on site and space limitations, construction lifting capabilities and site construction limitations, as well as other key considerations specific to each plant site. This technical paper discusses a number of arrangements, technical selection and layout criteria. This paper discusses case studies and design details of approximately 20,000 MW of successful bypass system equipment which improve system performance, reduce pressure drop, reduce abrasive wear, substantially minimize maintenance costs and simplify operating requirements.
Coal Based Methanol for Use in Fuel Cells: Research Needed
Authors: Erickson Paul A. , Kamisky Robert J. , Moock Nathan
Published: November 2008

Recent interest in hydrogen fuel cells and fuel cell vehicles as well as interest in the energy independence of the United States has prompted investigation into the question of using methanol derived from domestic coal as a primary source for hydrogen production. Since 1983 Eastman Chemical Company has been utilizing methanol from high sulfur coal feedstock in the production of acetic anhydride and acetic acid at their Chemicals from Coal Facility in Kingsport, TN. The Chemicals from Coal Facility was the first use of a commercial Texaco coal gasifier to provide clean syngas for the production of acetyl chemicals. Methanol is produced as an intermediate step in the process in a Lurgi fixed catalyst bed gas phase reactor and in a newer “Liquid Phase” slurry process, which was built in 1997 as a joint venture between Eastman, Air Products and Chemicals Inc., and the Department of Energy. Initial testing has indicated that hydrogen can be derived from this coal-based fuel but impurities were seen as problematic, especially for utilization in fuel cells. The coal-derived methanol has since been further refined and distilled, yet no full analysis of the hydrogen produced from this refined product for fuel cell applications has taken place. This paper will discuss the fuel pathway from coal to hydrogen, including a description of the Eastman’s Coal Gasification Process and methanol production facilities as well as the research underway to quantify production of hydrogen from this coal-based methanol utilizing the latest reforming technologies for use in a Polymer Electrolyte (PEM) fuel cell.
The Next Generation of Air Supply Units
Authors: Beaver Janvier E. , Hering Karl
Published: November 2008

This paper describes the evolution of the original Air Supply Units as oil-lubricated piston compressors to the new range of Knorr-Bremse Oil-Less Piston Compressors. These compressors will provide reliable, cost-effective, operation in a railway environment. The design features of the Oil-Free Piston Compressor are described and the operational advantages over conventional oil-lubricated reciprocating compressors are highlighted.
Results of Investigation of the Properties of Railway Vehicles With the New Design of Wheelsets Using the Computer Models and Field Tests
Authors: Vinnik Leonid V. , Bourtchak Guenrikh P.
Published: November 2008

The results of linking research on analysis of the railway vehicle properties with the new designs of wheelsets, allowing various angular velocities of the tread rotations relative to the hubs by retaining gravitational-frictional torsional connection between them, are considered. Through an analysis of dynamic features during the hunting motion of the vehicle, carried out on the computer model using the nonlinear creep theories, the advantages of this design are found, which include first of all the decrease of wheel and rail wear, and improvement of dynamic features. The issue of metro car motion in the traction mode is specially considered. Tests on physical models and field tests of the tram and metro car verified the results received on numerical models.
Traction Power Systems Reliability Concepts
Authors: Sagareli Sergo
Published: November 2008

Reliability of a traction power system may be defined as its ability to continuously supply electrical power of adequate quality during sudden disturbances such as a short circuit or loss of system elements, while operating with a normal scheme configuration, or during scheduled maintenance and repairs, without causing safety hazards, train delays or public nuisance. While the utility power systems’ reliability may be expressed in outage minutes per year (or any other time period), which is calculated as a ratio of customers’ electrical energy deprivation to system’s total power capacity, for a traction power systems’ reliability evaluation, minutes of train delays caused by power interruption or relative values such as delay minutes per passenger-mile may be utilized. Considering the accelerated growth of traction power systems across the US in recent and coming years [1], creation of a reliability council similar to NERC [2] to develop reliability standards within the railroad industry may be highly beneficial: it could pull together statistical data on reliability from different railroads, analyze them, and develop guidelines and recommendations for optimal solutions to provide adequate reliability with the lowest cost possible. IEEE Traction Power Substation Committee and AREMA Committee 33 on Electrical Energy Utilization could initiate and lay groundwork for the creation of such a council. While most of the contingency situations may be predicted and counteracted on the design stage, only the real-life experience is the ultimate test for reliability. That’s why it is so important to keep and analyze records of any outages and contingencies encountered during traction power system operations. Records for these purposes may be provided by Multi-Purpose Relays [3] that become widely used in recently built substations. Classification of voltage events in future Standard may be based on the Institute of Electrical and Electronic Engineers Standard 1159-1995 “IEEE Recommended Practice for Monitoring Electric Power Quality” [4], classification of reliability events — according to NERC Planning Standards [2].
Advanced Light Rail Vehicle Communication Systems Design
Authors: Swanson John D.
Published: November 2008

The use of electronic subsystems to perform complex tasks has grown in the consumer goods and automotive sectors to such a degree that these capabilities have become commonplace, yet in the field of light rail vehicles, they have made relatively little impact. The technology exists today to provide greatly increased passenger safety, security and system operational efficiency by the judicious application of mature subsystem designs. Such systems include radio based, fully integrated vehicle management systems with GPS, silent alarm capability and passenger information control, external passenger door and coupler monitoring video cameras, forward facing video recording for accident investigations, interior video recording for reduction in vandalism, interior video cameras linked to Passenger to Operator Intercoms to provide the Operator with more information and the transfer of data to and from vehicles via wireless LAN. This paper will describe the application of these subsystems to the new Phoenix light rail vehicle and project what the future may hold.
Hardware-Software Structure for On-Line Power Quality Assessment: Part I
Authors: Moussa Abd-Elmoniem , El-Gammal Mahmoud , Abdallah Emtethal , El-Seoud Ahmed Abou
Published: November 2008

The main objective of the proposed work is to introduce a new concept of advanced power quality assessment. The introduced system is implemented using applications of a set of powerful software algorithms and a digital signal processor based hardware data acquisition system. The suggested scheme is mainly to construct a system for real time detection and identification of different types of power quality disturbances that produce a sudden change in the power quality levels. Moreover, a new mitigation technique through generating feedback correction signals for disturbance compensation is addressed. The performance of the suggested system is tested and verified through real test examples. The obtained results reveal that, the introduced system detects fast and accurately most of the power quality disturbance events and introduces new indicative factors estimating the performance of any supply system subjected to a set number of disturbance events.
Computation and Validation of Rail-to-Earth Potential for Diode-Grounded DC Traction System at Taipei Rapid Transit System
Authors: Ku Bih-Yuan , Hsu Thomas
Published: November 2008

In this paper we present a case study of frequent surges of unusually high rail-to-earth potential values at Taipei Rapid Transit System. The rail potential values observed and the resulting stray current flow associated with the diode-ground DC traction system during operation are contradictory to the moderate values on which the grounding of the DC traction system design was based. Thus we conducted both theoretical study and field measurements to obtain better understanding of the phenomenon, and to develop a more accurate algorithm for computing the rail-to-earth potential of the diode-ground DC traction systems.
Analysis of Dynamic MRTS Traction Power Supply System Based on Dependent Train Movement Simulation
Authors: Yu Di , Lo K. L. , Wang Xiao Dong , Yin Chuan Gui , Huang De Liang
Published: November 2008

As the motivation in developing modern MRTS and the upgrading of old systems in many metropolitans all over the world, especially for public transportation in developing countries, the demand to simulate the dynamic traction power supply system (TPSS) more effectively and practically has increased. This paper describes the work of simulating and analysing TPSS. It is based on dependent train movement in conjunction with TPSS simulation to establish a panorama view of the features. The free time scheduled strategy for train movement is applied which is more flexible and effective to reflect operation strategies. To set up the dynamic TPSS structure with respect to the moving train status for the system solution, the schematic arrangement is split into four parts: establishment of the elementary electric network framework; establishment of the dynamic electrical network structure which includes both the elementary power network and the moving trains statuses; dynamic electric network simulation; and system analyses based on the panoramic features drawn from the simulation. The simulation results are based on the Shanghai Metro Line One (excluding the extension section). Simulation and analysis on more lines including Shanghai Line Two and Guangzhou Line One MTRS have also been implemented using similar approaches. The complete profiles of the TPSS provide a practical means in analysing the system configuration as well as organizing the system operation.
Wheel Wear Management on High-Speed Passenger Rail: A Common Playground for Design and Maintenance Engineering in the Talgo Engineering Cycle
Authors: Pascual Fernando , Marcos Jose-Antonio
Published: November 2008

Talgo’s focus on engineering excellence has helped the group to deliver innovative rail products to the market since 1942. Patentes Talgo S.A. (PTSA) provides passenger rail administrations around the world with high speed cars and locomotives, car maintenance equipment and maintenance services. The paper outlines the US experience of Talgo’s Total Logistics Care (TLC) maintenance program, summarizing Talgo’s maintenance approach, practice and overall results. The preventive and corrective maintenance program, the continuous trainset monitoring and the maintenance & design engineering cycle will be covered among other topics. Rolling assembly maintenance and wheel wear management are the two focal points of this paper. Talgo’s rolling assembly design has evolved over 60 years taking full advantage of the design-maintenance engineering cycle. Maintenance engineers and technicians, wheel assembly design engineers and maintenance equipment design engineers work together on a daily basis to improve the design of the rolling assembly and reduce maintenance costs and wheel wear. Enhanced guidance systems and other design improvements help to reduce flange wear on independent axle wheelsets. Also, five decades of in-house maintenance and wheel turning experience using Talgo pit lathes revealed the cutting parameters and frequencies to maximize wheel life. Both wheel wear management design and maintenance practices will be reviewed in the paper.
Analysis of Colliding Vehicle Interactions for the Passenger Rail Train-to-Train Impact Test
Authors: Stringfellow Richard , Rancatore Robert , Llana Patricia , Mayville Ronald
Published: November 2008

A full-scale train-to-train impact test was performed in which a cab car-led passenger train traveling at 30 mph collided with a standing locomotive-led train. During the test, the lead cab car overrode the cab of the standing locomotive, sustaining approximately 20 feet of crush, while the cab of the locomotive remained essentially intact. In this study, a finite element-based analysis of the collision was performed. The first 0.5 seconds of the collision was simulated. Results of the analysis were compared with accelerometer and video test data. Specific comparisons are made between test data and model predictions for: motions of the cab car and the standing locomotive; longitudinal forces arising between the cab car and the standing locomotive and between the respective lead and trailing vehicles; and the mode of deformation of the cab car and the locomotive. The results of the study indicate that the model captures pertinent features of the first 0.3 seconds of the collision, particularly with respect to longitudinal vehicle motions and collision forces. After 0.3 seconds, agreement between model predictions and test data becomes progressively worse. This is attributable to the model’s inability to capture the massive fracture that occurs at the front of the cab car.
PATH’s Downtown Restoration Program
Authors: Childs Frederick R. , Bulayev Radomir
Published: November 2008

On September 11, 2001, the terrorist attacks that destroyed the World Trade Center (WTC) in Lower Manhattan, New York City, also damaged the Port Authority Trans-Hudson Corp.’s (PATH’s) busiest terminal serving the heart of the thriving downtown financial, commercial, and residential district. The aftermath of the attacks also forced the closure of PATH’s key station at Exchange Place that serves Jersey City, New Jersey’s expanding “Gold Coast” business and residential area. PATH’s more than 260,000 average weekday commuters between New Jersey and New York were affected in some way by these tragic events, and PATH ridership fell sharply during the following months. Among the PATH facilities that were damaged or destroyed at WTC, and in the two Hudson River tubes, and at Exchange Place Station were all of the electrical, power, signal, and communications systems. Recovery and restoration work began immediately, but was hampered by the extensive rescue, recovery, removal, and demolition work at the World Trade site. Broken water lines and fire fighting efforts flooded both river tubes, which were later sealed at Exchange Place to prevent additional potential damage to PATH’s New Jersey facilities. This paper describes PATH’s recovery program to replace the electrical, power, signal, and communications facilities from Exchange Place to the WTC Terminal. A temporary WTC terminal has been built to restore direct service to Lower Manhattan’s financial, business, and residential center as of November 23, 2003. As part of this program, new trackwork was installed to enhance operational flexibility and provide temporary interim service to Exchange Place Station, which reopened June 29, 2003. Capacity expansion provisions were included to allow for future 10-car train operations when a new rail car fleet is procured. Facilities replaced include a new traction power and auxiliary services substation, new cables, ductbanks, new signals and central control system, wayside phones, emergency power removal switches, tunnel lighting, radio antenna, and fiber optics. An accelerated design and construction schedule was followed, using a broad combination of in-house, consulting, and contractor forces.
Investigation of Train Dynamics in Passing Through Curves Using a Full Model
Authors: Durali Mohammad , Jalili Bahabadi Mohammad Mehdi
Published: November 2008

In this article a train model is developed for studying train derailment in passing through bends. The model is three dimensional, nonlinear, and considers 43 degrees of freedom for each wagon. All nonlinear characteristics of suspension elements as well as flexibilities of wagon body and bogie frame, and the effect of coupler forces are included in the model. The equations of motion for the train are solved numerically for different train conditions. A neural network was constructed as an element in solution loop for determination of wheel-rail contact geometry. Derailment factor was calculated for each case. The results are presented and show the major role of coupler forces on possible train derailment.
SOS Regulation of
qnrB
Expression
Authors: Wang Minghua , Jacoby George A. , Mills Debra M. , Hooper David C.
Published: November 2008

In the sequence upstream from
qnrB
(but not
qnrA
or
qnrS
) is a LexA binding site.
qnrB
was shown to be under SOS control by demonstrating that quinolone susceptibility decreased with increasing temperature in a strain with a
recA441
(Ts) allele, whereas
qnrB
expression increased in response to ciprofloxacin or mitomycin C in strains with an intact
lexA
gene.
Evaluation of Strategies for Improving Proteolytic Resistance of Antimicrobial Peptides by Using Variants of EFK17, an Internal Segment of LL-37
Authors: Strömstedt Adam A. , Pasupuleti Mukesh , Schmidtchen Artur , Malmsten Martin
Published: November 2008

Methods for increasing the proteolytic stability of EFK17 (EFKRIVQRIKDFLRNLV), a new peptide sequence with antimicrobial properties derived from LL-37, were evaluated. EFK17 was modified by four d-enantiomer or tryptophan (W) substitutions at known protease cleavage sites as well as by terminal amidation and acetylation. The peptide variants were studied in terms of proteolytic resistance, antibacterial potency, and cytotoxicity but also in terms their adsorption at model lipid membranes, liposomal leakage generation, and secondary-structure behavior. The W substitutions resulted in a marked reduction in the proteolytic degradation caused by human neutrophil elastase,Staphylococcus aureusaureolysin, and V8 protease but not in the degradation caused byPseudomonas aeruginosaelastase. For the former two endoproteases, amidation and acetylation of the terminals also reduced proteolytic degradation but only when used in combination with W substitutions. The d-enantiomer substitutions rendered the peptides indigestible by all four proteases; however, those peptides displayed little antimicrobial potency. The W- and end-modified peptides, on the other hand, showed an increased bactericidal potency compared to that of the native peptide sequence, coupled with a moderate cytotoxicity that was largely absent in serum. The bactericidal, cytotoxic, and liposome lytic properties correlated with each other as well as with the amount of peptide adsorbed at the lipid membrane and the extent of helix formation associated with the adsorption. The lytic properties of the W-substituted peptides were less impaired by increased ionic strength, presumably by a combination of W-mediated stabilization of the largely amphiphilic helix conformation and a nonelectrostatic W affinity for the bilayer interface. Overall, W substitutions constitute an interesting means to reduce the proteolytic susceptibility of EFK17 while also improving antimicrobial performance.
Genetic Variability among
ampC
Genes from
Acinetobacter
Genomic Species 3
Authors: Beceiro Alejandro , Pérez Astrid , Fernández-Cuenca Felipe , Martínez-Martínez Luis , Pascual Alvaro , Vila Jordi , Rodríguez-Baño Jesús , Cisneros Jose Miguel , Pachón Jerónimo , Bou Germán
Published: November 2008

As a part of a nationwide study in Spain, 15 clinical isolates of
Acinetobacter
genomic species 3 (AG3) were analyzed. The main objective of the study was to characterize the
ampC
genes from these isolates and to determine their involvement in β-lactam resistance in AG3. The 15 AG3 isolates showed different profiles of resistance to ampicillin (range of MICs, 12 to >256 μg/ml). Nucleotide sequencing of the 15
ampC
genes yielded 12 new AmpC enzymes (ADC-12 to ADC-23). The 12 AG3 enzymes showed 93.7 to 96.1% amino acid identity with respect to the AmpC enzyme from
Acinetobacter baumannii
(ADC-1 enzyme). Eight out of fifteen
ampC
genes were expressed in
Escherichia coli
cells under the control of a common promoter, and with the exception of one isolate (isolate 65, which showed lower β-lactam MICs), significant differences in overall β-lactam MICs for
E. coli
cells expressing AG3
ampC
genes were not revealed. No significant differences in
ampC
gene expression in AG3 clinical isolates were revealed by reverse transcription-PCR analysis. A detailed analysis of the 12 AmpC protein sequences revealed that amino acid replacements (in comparison with those of ADC-1) occurred mainly in the same positions, although none were located in important functional domains such as the Ω- loop or conserved β-lactamase motifs. Kinetic experiments performed with three representative AmpC enzymes (ADC-14, -16, and -18) in some cases revealed dramatic changes in

K
m

and
k
cat
values for β-lactams. No IS
Aba1
was detected upstream of the
ampC
genes. Our results reveal 12 new
ampC
genes in AG3. The enzymes showed a moderate degree of variability, and they are tentatively named ADC-12 to ADC-23.
Ultrastructural Effects of Oritavancin on Methicillin-Resistant
Staphylococcus aureus
and Vancomycin-Resistant
Enterococcus
Authors: Belley Adam , Harris Robert , Beveridge Terry , Parr Tom , Moeck Gregory
Published: November 2008

The ultrastructural effects of the lipoglycopeptide oritavancin on methicillin-resistant
Staphylococcus aureus
(MRSA) and vancomycin-resistant enterococcus (VRE) were examined by transmission electron microscopy. Oritavancin but not vancomycin induced aberrant septum formation and loss of staining of nascent septal cross walls in MRSA. Septal distortions were also observed in VRE exposed to oritavancin.
Activities of Certain 5-Substituted 4′-Thiopyrimidine Nucleosides against Orthopoxvirus Infections
Authors: Kern Earl R. , Prichard Mark N. , Quenelle Debra C. , Keith Kathy A. , Tiwari Kamal N. , Maddry Joseph A. , Secrist John A.
Published: November 2008

As part of a program to identify new compounds that have activity against orthopoxviruses, a number of 4′-thionucleosides were synthesized and evaluated for their efficacies against vaccinia and cowpox viruses. Seven compounds that were active at about 1 μM against both viruses in human cells but that did not have significant toxicity were identified. The 5-iodo analog, 1-(2-deoxy-4-thio-β-d-ribofuranosyl)-5-iodouracil (4′-thioIDU), was selected as a representative molecule; and this compound also inhibited viral DNA synthesis at less than 1 μM but only partially inhibited the replication of a recombinant vaccinia virus that lacked a thymidine kinase. This compound retained complete activity against cidofovir- and ST-246-resistant mutants. To determine if this analog had activity in an animal model, mice were infected intranasally with vaccinia or cowpox virus and treatment with 4′-thioIDU was given intraperitoneally or orally twice daily at 50, 15, 5, or 1.5 mg/kg of body weight beginning at 24 to 120 h postinfection and was continued for 5 days. Almost complete protection (87%) was observed when treatment with 1.5 mg/kg was begun at 72 h postinfection, and significant protection (73%) was still obtained when treatment with 5 mg/kg was initiated at 96 h. Virus titers in the liver, spleen, and kidney were reduced by about 4 log10units and about 2 log10units in mice infected with vaccinia virus and cowpox virus, respectively. These results indicate that 4′-thioIDU is a potent, nontoxic inhibitor of orthopoxvirus replication in cell culture and experimental animal infections and suggest that it may have potential for use in the treatment of orthopoxvirus infections in animals and humans.
Leptospira interrogansInduces Apoptosis in Macrophages via Caspase-8- and Caspase-3-Dependent Pathways
Authors: Jin Dandan , Ojcius David M. , Sun Dexter , Dong Haiyan , Luo Yihui , Mao Yafei , Yan Jie
Published: November 2008

Apoptosis of host cells plays an important role in modulating the pathogenesis of many infectious diseases. It has been reported thatLeptospira interrogans, the causal agent of leptospirosis, induces apoptosis in macrophages and hepatocytes. However, the molecular mechanisms responsible for host cell death remained largely unknown. Here we demonstrate thatL. interrogansinduced apoptosis in a macrophage-like cell line, J774A.1, and primary murine macrophages in a time- and dose-dependent manner. Apoptosis was associated with the activation of cysteine aspartic acid-specific proteases (caspase-3, caspase-6, and caspase-8), the increased expression of Fas-associated death domain (FADD), and the cleavage of the caspase substrates poly(ADP-ribose) polymerase (PARP) and nuclear lamina protein (lamin A and lamin C). Caspase-9 was activated to a lesser extent, whereas no release of cytochromecfrom mitochondria was detectable. Inhibition of caspase-8 impairedL. interrogans-induced caspase-3 and -6 activation, as well as PARP and lamin A/C cleavage and apoptosis, suggesting that apoptosis is initiated via caspase-8 activation. Furthermore, caspase-3 was required for the activation of caspase-6 and seemed to be involved in caspase-9 activation through a feedback amplification loop. These data indicate thatL. interrogans-induced apoptosis in macrophages is mediated by caspase-3 and -6 activation through a FADD-caspase-8-dependent pathway, independently of mitochondrial cytochromec-caspase-9-dependent signaling.
Interaction of Enteric Bacterial Pathogens with Murine Embryonic Stem Cells
Authors: Yu Jun , Rossi Raffaella , Hale Christine , Goulding David , Dougan Gordon
Published: November 2008

Embryonic stem (ES) cells are susceptible to genetic manipulation and retain the potential to differentiate into diverse cell types, which are factors that make them potentially attractive cells for studying host-pathogen interactions. Murine ES cells were found to be susceptible to invasion bySalmonella entericaserovar Typhimurium andShigella flexneriand to the formation of attaching and effacing lesions by enteropathogenicEscherichia coli. S. entericaserovar Typhimurium andS. flexnericell entry was dependent on theSalmonellapathogenicity island 1 andShigella mxi/spatype III secretion systems, respectively. Microscopy studies indicated that bothS. entericaserovar Typhimurium andS. flexneriwere located in intracellular niches in ES cells that were similar to the niches occupied in differentiated cells. ES cells were eventually killed following bacterial invasion, but no evidence of activation of classical caspase-associated apoptotic or innate immune pathways was found. To demonstrate the potential of mutant ES cells, we employed an ES cell line defective in cholesterol synthesis and found that the mutant cells were less susceptible to infection bySalmonellaandShigellathan the parental ES cells. Thus, we highlighted the practical use of genetically modified ES cells for studying microbe-host interactions.
Vaccination with Proteus Toxic Agglutinin, a Hemolysin-Independent Cytotoxin In Vivo, Protects against
Proteus mirabilis
Urinary Tract Infection
Authors: Alamuri Praveen , Eaton Kathryn A. , Himpsl Stephanie D. , Smith Sara N. , Mobley Harry L. T.
Published: November 2008

Complicated urinary tract infections (UTI) caused by
Proteus mirabilis
are associated with severe pathology in the bladder and kidney. To investigate the roles of two established cytotoxins, the HpmA hemolysin, a secreted cytotoxin, and proteus toxic agglutinin (Pta), a surface-associated cytotoxin, mutant analysis was used in conjunction with a mouse model of ascending UTI. Inactivation of
pta
, but not inactivation of
hpmA
, resulted in significant decreases in the bacterial loads of the mutant in kidneys (
P
< 0.01) and spleens (
P
< 0.05) compared to the bacterial loads of the wild type; the 50% infective dose (ID
50
) of an isogenic
pta
mutant or
hpmA pta
double mutant was 100-fold higher (5 × 10
8
CFU) than the ID
50
of parent strain HI4320 (5 × 10
6
CFU). Colonization by the parent strain caused severe cystitis and interstitial nephritis as determined by histopathological examination. Mice infected with the same bacterial load of the
hpmA pta
double mutant showed significantly reduced pathology (
P
< 0.01), suggesting that the additive effect of these two cytotoxins is critical during
Proteus
infection. Since Pta is surface associated and important for the persistence of
P. mirabilis
in the host, it was selected as a vaccine candidate. Mice intranasally vaccinated with a site-directed (indicated by an asterisk) (S366A) mutant purified intact toxin (Pta*) or the passenger domain Pta-α*, each independently conjugated with cholera toxin (CT), had significantly lower bacterial counts in their kidneys (
P
= 0.001) and spleens (
P =
0.002) than mice that received CT alone. The serum immunoglobulin G levels correlated with protection (
P
= 0.03). This is the first report describing the in vivo cytotoxicity and antigenicity of an autotransporter in
P. mirabilis
and its use in vaccine development.
Numerical modelling of a centrifuged embankment on soft clay
Authors: Almeida M. S. S. , Britto A. M. , Parry R. H. G.
Published: November 2008

Biot coupled consolidation numerical analyses have been applied to a stage-constructed embankment on soft clay in the centrifuge. In the test, the sand embankment was constructed during flight on a clay foundation consisting of an overconsolidated crust overlying a normally consolidated layer. Measurements were taken of pore pressures, dissipation rates, and displacements in the foundation clay. Predictions of these were made using a simple Cam-clay model for the clay and the Cambridge CRISP computer program. A linear elastic idealization was used for the embankment. With some exceptions, pore pressures and dissipation rates were very well predicted, as were maximum values of both horizontal and vertical displacements. However, displacement profiles with depth were not so well predicted. Particular attention is given in the paper to the determination of relevant values of shear modulus G and the difference in behaviour resulting from using constant permeability and permeability varying with void ratio. Key words: embankments, soft clay, centrifuge test, numerical analysis, Biot consolidation, Cam-clay model.
Analysis of bearing capacity of rigid piles under eccentric and inclined loads
Authors: Koumoto T. , Meyerhof G. G. , Sastry V. V. R. N.
Published: November 2008

An investigation is made of the eccentricity and inclination factors for estimating the ultimate bearing capacity of rigid single piles in homogeneous soils under eccentric and inclined loads. For combined eccentric inclined loads the corresponding theoretical factors are obtained by combining inclination factors and eccentricity factors, which are derived from extending the theory of inclination factors for shallow strip footings. The theoretical values of inclination factors, eccentricity factors, and eccentric inclination factors are compared with some experimental results of model piles in sand and clay. Key words: bearing capacity, clay, eccentricity factors, eccentric inclination factors, inclination factors, rigid piles, sand, ultimate load.
Depth profiling of peat deposits with impulse radar
Authors: Worsfold Richard D. , Parashar Surendra K. , Perrott Timothy
Published: November 2008

With the growing interest in peat as an energy fuel, the need for better inventories of this resource becomes increasingly important. Although conventional imaging sensors can provide information on the areal extent of peatlands, depth measurements must still be taken in the field in order to estimate the volume of material present. A recently completed program conducted in eastern Newfoundland suggests that impuse radar systems can provide depth information and volume estimates comparable to those obtained with manual measurement techniques. Ground-based data were acquired using 80- and 400-MHz radar systems and airborne data were collected using 80- and 120-MHz systems. For ground-based profiles, peat thickness of up to 8.1 m was clearly measureable. The airborne profile data were generally poorer in quality; however, depths of up to 4.8 m were successfully profiled from an altitude of 1.5 m. No significant seasonal variations were observed. Impulse radar techniques seem to be particularly useful for reconnaissance level surveys. Additional research is needed in order to develop a system suitable for airborne profiling. Key words: impulse radar, peat resources, peatlands, Newfoundland, depth, volume, profiling, airborne profiling, radar propagation.
Change in pile capacity with time: case histories
Authors: Samson Laval , Authier Jean
Published: November 2008

Four case histories where important changes in pile capacity were observed with time are presented. Two show an increase of pile capacity for shaft bearing piles driven into deep sand deposits. The increase occurred over a period longer than needed for pore pressure dissipation. In one case, increases of 33 and 85% in pile capacity were measured 2 and 51 days, respectively, after pile driving. The other two case histories deal with the decrease of pile capacity of close-toe pipe piles driven to shale bedrock. The decrease, determined using dynamic monitoring during initial driving and at restriking a few days later, ranged from 11 to 25%. It is concluded that restriking should be currently practiced on all construction sites to investigate any change in pile capacity after driving. This procedure is particularly recommended for toe bearing piles on shale bedrock. Key words: pile capacity, shaft bearing piles, toe bearing piles, relaxation, soil setup, pile dynamic analysis, shale, time factor, case histories.
Fracture permeability and groundwater flow in clayey till near Saskatoon, Saskatchewan
Authors: Keller C. Kent , Kamp Garth van der , Cherry John A.
Published: November 2008

Field and laboratory studies of a clayey unweathered glacial till have shown that its bulk permeability exceeds its matrix permeability by two orders of magnitude. Such findings are common for weathered till but are rare for unweathered till, and have important implications for groundwater recharge and contaminant transport. The till in question is 6 m thick and appears to be unweathered and unfractured. It is overlain by 12 m of weathered and highly fractured till. Results of consolidation tests on the unweathered till indicate a mean vertical hydraulic conductivity of 3.5 × 10−11 m∙s−1 and a mean specific storage of 1.3 × 10−4 m−1. Results of slug tests yield a horizontal hydraulic conductivity of about 5 × 10−9 m∙s−1. Drawdowns in the till in response to pumping from the aquifer below indicate a vertical hydraulic diffusivity of 4.5 × 10−5m2∙s−1. The slug test results combined with specific storage results from consolidation tests indicate a similar value for horizontal hydraulic diffusivity of 4 × 10−5 m2∙s−1. Geochemical patterns, tritium data, and measured seepage fluxes from an ephemeral pond also indicate that the vertical conductivity of the unweathered till is much higher than the value obtained from the consolidation tests. The data thus show that the unweathered till has significant vertical and horizontal fracture permeability. Key words: till, permeability, fracture, groundwater recharge, contaminant transport.
Determination of the consistency limits of soils by the fall cone test
Authors: Wasti Y. , Bezirci M. H.
Published: November 2008

The liquid and plastic limits for a variety of natural and artificial soils covering a wide range of plasticity, as determined by the Casagrande method and the fall cone test and based on a strength criterion, were compared. To check the validity of the strength criterion, the undrained shear strength of these soils has been determined with a laboratory vane over the water content range between these limits. A limited comparison of the undrained strength values obtained from the vane test and fall cone test is also given. Key words: Atterberg limits, consistency, fall cone, laboratory vane, shear strength.
Archaeology from a Swiss test boring
Authors: Legget R. F. , Schriever W. R.
Published: November 2008

A test boring on a building site in Zurich, Switzerland, revealed the existence of archaeological remains beneath the site through the observation of a stone axe found in examination of one of the cores. Redesign of the foundations permitted careful excavation for the basements, by archaeologists, while superstructure erection proceeded. The significant findings are a useful reminder of the importance of proper supervision of all site exploration work. Key words: archaeology, site investigation, supervision.
Peroxiredoxin-6 protects against mitochondrial dysfunction and liver injury during ischemia-reperfusion in mice
Authors: Eismann Thorsten , Huber Nadine , Shin Thomas , Kuboki Satoshi , Galloway Elizabeth , Wyder Michael , Edwards Michael J. , Greis Kenneth D. , Shertzer Howard G. , Fisher Aron B. , Lentsch Alex B.
Published: November 2008

Hepatic ischemia-reperfusion (I/R) injury is an important complication of liver surgery and transplantation. Mitochondrial function is central to this injury. To examine alterations in mitochondrial function during I/R, we assessed the mitochondrial proteome in C57Bl/6 mice. Proteomic analysis of liver mitochondria revealed 234 proteins with significantly altered expression after I/R. From these, 13 proteins with the greatest expression differences were identified. One of these proteins, peroxiredoxin-6 (Prdx6), has never before been described in mitochondria. In hepatocytes from sham-operated mice, Prdx6 expression was found exclusively in the cytoplasm. After ischemia or I/R, Prdx6 expression disappeared from the cytoplasm and appeared in the mitochondria, suggesting mitochondrial trafficking. To explore the functional role of Prdx6 in hepatic I/R injury, wild-type and Prdx6-knockout mice were subjected to I/R injury. Prdx6-knockout mice had significantly more hepatocellular injury compared with wild-type mice. Interestingly, the increased injury in Prdx6-knockout mice occurred despite reduced inflammation and was associated with increased mitochondrial generation of H2O2 and dysfunction. The mitochondrial dysfunction appeared to be related to complex I of the electron transport chain. These data suggest that hepatocyte Prdx6 traffics to the mitochondria during I/R to limit mitochondrial dysfunction as a protective mechanism against hepatocellular injury.
Pediatric Selective IgM Immunodeficiency
Authors: Goldstein Marc F. , Goldstein Alex L. , Dunsky Eliot H. , Dvorin Donald J. , Belecanech George A. , Shamir Kfir
Published: November 2008

Objective. Limited information exists on features of pediatric Selective IgM immunodeficiency (SIgMID). Previously published pediatric cases and 2 new cases are reviewed.Methods. English literature from PubMed and references from relevant articles were reviewed. Previously reported cases and 2 new cases from an allergy/immunology practice were analyzed.Results. Forty-nine reported cases of SIgMID presented with respiratory infections (77.6%), gastrointestinal disease (16.3%), skin disease (12.2%), and meningitis (8.2%). Mean serum IgM level was  mg/dL. Two patients were identified with SIgMID among 6300 active pediatric patients (0.03%) presenting with asthma, vasomotor rhinitis, and recurrent respiratory infections. In the 51 cases reported, none developed lymphoproliferative disease nor evolved into panhypogammaglobulinemia; four fatalities were reported.Conclusions. The prevalence of SIgMID in our pediatric population was 0.03%. In general, respiratory infections are the common comorbid conditions. Death and autoimmune disease are uncommon complications of pediatric SIgMID.
Well-Posedness and Fractals via Fixed Point Theory
Authors: Chifu Cristian , Petruşel Gabriela
Published: November 2008

The purpose of this paper is to present existence, uniqueness, and data dependence results for the strict fixed points of a multivalued operator of Reich type, as well as, some sufficient conditions for the well-posedness of a fixed point problem for the multivalued operator.
Observation and Analysis of Affinity Law Deviations through Tested Performance of Liquefied Gas Reaction Turbines
Authors: Alison-Youel Sarah D.
Published: November 2008

Liquefied gas reaction turbines are subject to the hydraulic affinity laws. Particularly for liquefied hydrocarbon gas‐driven turbines, deviations from the affinity laws are encountered. In the case of reaction turbines, where the geometry is fixed, the affinity law relationships between flow, head, and rotational speed are relevant. Field experience confirms that the affinity law relationships are adequate, but that the predictions made also tend to deviate from real turbine performance. Part of the deviations seen may be attributed to the nonideal fluid; however, further examination is warranted. This paper presents an investigation into the affinity law relationships between head, flow, and rotational speed in conjunction with actual turbine performance. The three basic affinity law relationships are combined to form the most general performance equation. This equation subsequently incorporates both the affinity law relationships and the conservation of energy principal. Application of real turbine test data shows that this general performance equation presents a more accurate representation of turbine performance than the affinity law relationships alone.
Disturbance Observer‐Based Simple Nonlinearity Compensation for Matrix Converter Drives
Authors: Lee Kyo-Beum , Blaabjerg Frede
Published: November 2008

This paper presents a new method to compensate the nonlinearity for matrix converter drives using disturbance observer. The nonlinearity of matrix converter drives such as commutation delay, turn‐on and turn‐off time of switching device, and on‐state switching device voltage drop is modeled by disturbance observer and compensated. The proposed method does not need any additional hardware and offline experimental measurements. The proposed compensation method is applied for high‐performance induction motor drives using a 3 kW matrix converter system without a speed sensor. Simulation and experimental results show that the proposed method using disturbance observer provides good compensating characteristics.
A Coding of Real Null Four‐Momenta into World‐Sheet Coordinates
Authors: Fairlie David B.
Published: November 2008

The results of minimizing the action for string‐like systems on a
simply connected world sheet are shown to encode the Cartesian components
of real null momentum four‐vectors into coordinates on the
world sheet. This identification arises consistently from different approaches
to the problem.