bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Roadway Worker Injuries and Fatalities at FRA and FTA-Regulated Railroads
Authors: Schlesinger Dave 
Published: June 2014

Roadway workers perform a key role in keeping the nation’s freight, passenger, and transit rail systems operating safely and efficiently. These individuals perform a variety of critical maintenance, repairs, and inspection on all aspects of the rail system.
Despite a renewed effort by the rail industry, fatalities and injuries to roadway workers continue to occur across the nation’s freight, passenger, and transit rail systems. The causes of these accidents are all human factor related, especially in the area of adherence to rules and procedures. Other factors include rules compliance and organizational issues.
At the same time, there is no unified and cohesive source from which railroads and other concerned organizations can gain a perspective of roadway worker safety issues.
Using accident reports and information available primarily from the National Transportation Safety Board (NTSB) as well as the FRA and FTA, and the railroad industry, research was conducted, with a focus on the probable causes and contributing factors. Research was also conducted on the various industry efforts, both public and private, to curb these fatalities and injuries.
One of these efforts has been to develop a roadway worker warning system, to notify employees of an approaching train. Those railroads who have implemented this solution have reported positive results; however, this technology has not been widely accepted. This may be, in part, due to major capital requirements, such as Positive Train Control, which limits funding for other programs.
Training best practices are also outlined, with the goal of ensuring that roadway workers understand the risks they face while working on the railroad. Strategies are presented to ensure that training is conducted following best practices, including key case studies whose real life examples help trainees understand the criticality of following the rules and procedures each and every time they work on the system.
Reliable Transfer Length Assessment for Real-Time Monitoring of Railroad Crosstie Production
Authors: Zhao Weixin , Beck B. Terry , Peterman Robert J. , Wu Chih-Hang John , Bodapati Naga Narendra B. , Lee Grace 
Published: June 2014

Automated in-plant diagnostic testing of prestressed concrete railroad crossties is now within reach due to recent progress in robust surface strain measurement techniques. The newly developed non-contact Laser Speckle Imaging (LSI) technique has been shown to provide rapid and accurate surface strain profile measurement, which is a key requirement for rapid transfer length assessment. Accurate determination of transfer length is critical for maintaining continuous production quality in the modern manufacture of prestressed concrete railroad crossties.
Conventional assessment of transfer length generally presumes the underlying existence of a bilinear prestressing force distribution and a corresponding bilinear surface strain profile. Furthermore, it is well-known that this bilinear profile is smoothed due to the effects of finite gauge length during the process of measuring surface strain. In addition, recent extensive crosstie measurements in concrete railroad tie plants have shown significant departures from this simple bilinear profile, which bring to question the general validity and reliability of the traditional 95% AMS (95% Average Maximum Strain) method. Deviations from the simple bilinear profile shape were shown to be partially due to the non-prismatic shape of typical concrete railroad ties. In addition, extensive comparisons between predicted and measured surface strain profiles on numerous crossties suggest that the underlying strain distribution for crossties is best represented by an exponential strain profile, with an asymptotic approach to the fully-developed compressive strain. This is in contrast with extensive testing of prisms with fixed cross-section and fixed prestressing wire eccentricity, for which the surface strain appears to be best represented by the simple bilinear strain profile.
Clearly, departures from non-prismatic behavior have added complexity to transfer length measurement. If accurate and reliable measurements of this important quality control parameter are to be realized, these issues of transfer length uncertainty need to be addressed. This paper provides an experimental comparison of several possible alternative transfer length assessment procedures, in an attempt to answer important uncertainty questions which need to be addressed if rapid real-time transfer length is to be achieved. It is shown that in spite of considerable differences in the transfer length processing methods, and significant departures from prismatic behavior, the averaged results are in many cases consistent with the simple bilinear underlying strain profile assumption. Bias in the measurement of crosstie transfer length due to non-prismatic behavior will also be investigated in this paper.
Hertzian Contact Stress Modeling in Railway Bearings for Assorted Load Conditions and Geometries
Authors: Mason Michael A. , Cartin Charles P. , Shahidi Parham , Fetty Mark W. , Wilson Brent M. 
Published: June 2014

Increasing freight car loads demand higher performance tapered roller bearings. As the stress state on railway bearing applications continues to increase, further advancement in the modeling tools and methods used for subsurface contact stress evaluations are needed. Heat treat specifications and contact geometries for railway bearings were originally developed for ideal load conditions. However, in railroad applications, tapered roller bearings are exposed to a vast range of load conditions that are seldom perfect. Moreover, when comparing global rail markets, there are often differences in bearing loads, railcar wear conditions, maintenance practices, and reliability versus utilization expectations. Advanced modeling techniques need to be developed by bearing designers in order to meet the specific needs of each individual rail market.
Prior research has shown that subsurface stresses, resulting from rolling contact, are the primary factor in the development of fatigue cracks in railway bearings. In addition, finite element modeling software has previously been used to analyze Hertzian contact stresses under rolling contact. Recent advancements in the technology and computational power of finite element methods can be used to numerically analyze more detailed simulations of complex geometries and biased load conditions in railway bearings. These improvements in the tapered roller bearing modeling methodology are necessary to determine the material, heat treat specifications, and geometry required to meet the demands of specific railway bearing applications. Furthermore, the specific risks associated with some common railway bearing design and modeling assumptions will be evaluated. An exploratory list of these assumptions include: line versus point contact, load deflection factor, zero contact angle, rigid body assumptions, linear material behavior, neglect for overload, and uniform loading on the bearing. Emphasis will be placed on potential improvements in the theoretical and finite element prediction of surface and subsurface stresses in railway bearings under rolling contact with a review of prior research on the subject.
Effect of Concrete Properties on Transfer Lengths in Concrete Rail-Road Ties
Authors: Bodapati Naga Narendra B. , Peterman Robert J. , Beck B. Terry , Wu Chih-Hang John 
Published: June 2014

This paper presents findings from a current research project titled “Quantifying the Effect of Prestressing Steel and Concrete Variables on the Transfer Length in Pretensioned Concrete Crossties” that is funded by the Federal Railroad Administration (FRA). Specifically, the paper focuses on the effect of concrete properties on the resulting transfer lengths. These properties include concrete consistency (slump), compressive strength at the time of prestress transfer, the water-to-cementitious (W/C) ratio, the aggregate type, and the use of a viscosity-modifying admixture (VMA). Pre-tensioned concrete prisms were cast in the laboratory and transfer lengths were determined from surface strain measurements that were obtained prior-to and immediately after prestress transfer (de-tensioning). The concrete compressive strength at de-tensioning was determined using cylindrical concrete test specimens that were match-cured to the temperature of the pre-tensioned concrete members. The release strengths investigated were 3500 psi (24.13 Mpa), 4500 psi (31.03 Mpa), and 6000 psi (41.37 Mpa). The effect of concrete consistency on the transfer length was evaluated by varying the slump between 3″ (76.20 mm) and 9″ (228.60 mm) while maintaining release strength of 4500 psi (31.03 Mpa) and a W/C ratio of 0.32. The effect of W/C ratio on transfer length was evaluated by maintaining release strength of 4500 ±220 psi (31.03 ± 1.52 Mpa) and a slump of 6 ± 1/2″ (152.40 ± 12.7 mm) while varying the W/C between 0.27 and 0.42. These values represent the extreme values used in the North American concrete tie industry that were noted by the authors during research that was conducted in 2010–2011[15]. Results for each parameter type will be compared and discussed in this paper. Transfer length results obtained during earlier work [4] conducted by the authors at a W/C ratio of 0.32 will be compared. Finally, results will be presented from transfer length measurements that were obtained on identical-sized prisms that were manufactured with concrete mixtures that used different aggregate sources and also the use of a viscosity-modifying admixture.
Work presented in this paper was conducted on two wire samples with generic labels [WG] and [WH]. Laboratory prism specimens of size 3 ½″ (88.9 mm) × 3 ½″ (88.9 mm) each with 4 wires were cast to measure transfer lengths. These proportions were chosen to replicate the original concrete crosstie wire-to-concrete proportions. Potential usage of these prisms in estimating transfer lengths was validated in another phase [5] and is not discussed here.
Essential information obtained from results allowed researchers to discuss attributed influence of each concrete property on transfer length. The research knowledge acquired from this study will give proper insight about transfer length and will be helpful to manufacture a better product by adjusting concrete mix design.
Protecting Fittings on Tank Cars: Preliminary Evaluation of Pressure Tank Cars
Authors: Prabhakaran Anand , González Francisco 
Published: June 2014

Railroad tank car top fittings are susceptible to damage and failure in rollover derailments, which might result in release of hazardous material lading. Prior research has focused on the susceptibility of fittings on non-pressure tank cars and potential mitigation strategies. This paper presents current work that extends the analysis/test methods and lessons learned to fittings on pressure tank cars. Pressure tank cars carry significantly more hazardous materials such as Chlorine and Anhydrous Ammonia, which are classified as Toxic Inhalation Hazards (TIH). In particular, this paper presents the results of analytical modeling and validation testing of top fittings on a base design Chlorine car.
In addition, the paper compares and contrasts the test methodology employed in prior full scale tests of tank car fittings against the 9 mph evaluation scenario outlined in current Federal regulations governing the design of fittings on TIH tank cars, and further explores how full scale test results may be interpreted.
Intravitreal Injection of the Chimeric Phage Endolysin Ply187 Protects Mice from Staphylococcus aureus Endophthalmitis
Authors: Singh Pawan Kumar , Donovan David M. , Kumar Ashok 
Published: June 2014

ABSTRACT

The treatment of endophthalmitis is becoming very challenging due to the emergence of multidrug-resistant bacteria. Hence, the development of novel therapeutic alternatives for ocular use is essential. Here, we evaluated the therapeutic potential of Ply187AN-KSH3b, a chimeric phage endolysin derived from the Ply187 prophage, in a mouse model of
Staphylococcus aureus
endophthalmitis. Our data showed that the chimeric Ply187 endolysin exhibited strong antimicrobial activity against both methicillin-sensitive
S. aureus
and methicillin-resistant
S. aureus
(MRSA) strains, as evidenced by MIC determinations, reductions in turbidity, and disruption of biofilms. Moreover, exposure of
S. aureus
to Ply187 for up to 10 generations did not lead to resistance development. The intravitreal injection of chimeric Ply187 (at 6 or 12 h postinfection) significantly improved the outcome of endophthalmitis, preserved retinal structural integrity, and maintained visual function as assessed by electroretinogram analysis. Furthermore, phage lysin treatment significantly reduced the bacterial burden and the levels of inflammatory cytokines and neutrophil infiltration in the eyes. These results indicate that the intravitreal administration of a phage lytic enzyme attenuates the development of bacterial endophthalmitis in mice. To the best of our knowledge, this is the first study demonstrating the therapeutic use of phage-based antimicrobials in ocular infections.
Population-Based Cohort Study of Anti-Infective Medication Use before and after the Onset of Type 1 Diabetes in Children and Adolescents
Authors: Fazeli Farsani Soulmaz , Souverein Patrick C. , van der Vorst Marja M. J. , Knibbe Catherijne A. J. , de Boer Anthonius , Mantel-Teeuwisse Aukje K. 
Published: June 2014

ABSTRACT

A population-based cohort study was conducted in the Dutch PHARMO database to investigate prevalence and patterns of anti-infective medication use in children and adolescents with type 1 diabetes (T1D) before and after the onset of this disease. All patients <19 years with at least 2 insulin prescriptions (1999 to 2009) were identified (T1D cohort) and compared with an age- and sex-matched (ratio: 1 up to 4) diabetes-free reference group. The prevalence and average number of anti-infective use was studied from (up to) 8 years before until a maximum of 4 years after the onset of T1D. A total of 925 patients with T1D and 3,591 children and adolescents in the reference cohort (51% boys, mean age of 10.1 [standard deviation, 4.5] years) were included. The overall prevalence of anti-infective use (62.6 compared to 52.6%,
P
< 0.001) and average number of prescriptions (2.71 compared to 1.42 per child,
P
< 0.001) in the T1D cohort were significantly higher than those in the reference cohort after the onset of diabetes. This pattern was consistent across sex and age categories and already observed in the year before the onset of type 1 diabetes. Patients in the T1D cohort received more antibacterials (49.8 compared to 40%,
P
< 0.001), antimycotics (4.0 compared to 1.3%,
P
< 0.001), antivirals (2.5 compared to 0.4%,
P
< 0.001), and second-line antibiotics, such as aminoglycosides, quinolones, and third-generation cephalosporins and carbapenems. Our findings that elevated anti-infective use in the T1D cohort exists in the period before the onset of type 1 diabetes and the consumption of more second-line anti-infective compounds in this time period warrant further research.
Pyocyanin Stimulates Quorum Sensing-Mediated Tolerance to Oxidative Stress and Increases Persister Cell Populations in Acinetobacter baumannii
Authors: Bhargava Nidhi , Sharma Prince , Capalash Neena 
Published: June 2014

ABSTRACT

Acinetobacter baumannii
and
Pseudomonas aeruginosa
are nosocomial pathogens with overlapping sites of infection. This work reports that the two can coexist stably in mixed-culture biofilms. In a study intended to improve our understanding of the mechanism of their coexistence, it was found that pyocyanin, produced by
P. aeruginosa
that generally eliminates competition from other pathogens, led to the generation of reactive oxygen species (ROS) in
A. baumannii
cells, which in response showed a significant (
P
≤ 0.05) increase in production of enzymes, specifically, catalase and superoxide dismutase (SOD). This work shows for the first time that the expression of catalase and SOD is under the control of a quorum-sensing system in
A. baumannii
. In support of this observation, a quorum-sensing mutant of
A. baumannii
(
abaI
::Km) was found to be sensitive to pyocyanin compared to its wild type and showed significantly (
P
≤ 0.001) lower levels of the antioxidant enzymes, which increased on addition of 5 μM
N
-(3-hydroxydodecanoyl)-
l
-homoserine lactone. Likewise, in wild-type
A. baumannii
, there was a significant (
P
< 0.01) decrease in the level of anti-oxidant enzymes in the presence of salicylic acid, a known quencher of quorum sensing. In the presence of amikacin and carbenicillin,
A. baumannii
formed 0.07 and 0.02% persister cells, which increased 4- and 3-fold, respectively, in the presence of pyocyanin. These findings show that pyocyanin induces a protective mechanism in
A. baumannii
against oxidative stress and also increases its persistence against antibiotics which could be of clinical significance in the case of coinfections with
A. baumannii
and
P. aeruginosa
.
Morphogenesis Is Not Required for Candida albicans-Staphylococcus aureus Intra-Abdominal Infection-Mediated Dissemination and Lethal Sepsis
Authors: Nash Evelyn E. , Peters Brian M. , Palmer Glen E. , Fidel Paul L. , Noverr Mairi C. 
Published: June 2014

ABSTRACT

Intra-abdominal polymicrobial infections cause significant morbidity and mortality. An established experimental mouse model of
Staphylococcus aureus
-
Candida albicans
intra-abdominal infection results in ∼60% mortality within 48 h postinoculation, concomitant with amplified local inflammatory responses, while monomicrobial infections are avirulent. The purpose of this study was to characterize early local and systemic innate responses during coinfection and determine the role of
C. albicans
morphogenesis in lethality, a trait involved in virulence and physical interaction with
S. aureus
. Local and systemic proinflammatory cytokines were significantly elevated during coinfection at early time points (4 to 12 h) compared to those in monoinfection. In contrast, microbial burdens in the organs and peritoneal lavage fluid were similar between mono- and coinfected animals through 24 h, as was peritoneal neutrophil infiltration. After optimizing the model for 100% mortality within 48 h, using 3.5 × 10
7
C. albicans
(5× increase), coinfection with
C. albicans
yeast-locked or hypha-locked mutants showed similar mortality, dissemination, and local and systemic inflammation to the isogenic control. However, coinfection with the yeast-locked
C. albicans
mutant given intravenously (i.v.) and
S. aureus
given intraperitoneally (i.p.) failed to induce mortality. These results suggest a unique intra-abdominal interaction between the host and
C. albicans-S. aureus
that results in strong inflammatory responses, dissemination, and lethal sepsis, independent of
C. albicans
morphogenesis.
A Specific Polymorphism in Mycobacterium tuberculosis H37Rv Causes Differential ESAT-6 Expression and Identifies WhiB6 as a Novel ESX-1 Component
Authors: Solans Luis , Aguiló Nacho , Samper Sofía , Pawlik Alexandre , Frigui Wafa , Martín Carlos , Brosch Roland , Gonzalo-Asensio Jesús 
Published: June 2014

ABSTRACTThe ESX-1 secreted virulence factor ESAT-6 is one of the major and most well-studied virulence factors ofMycobacterium tuberculosis, given that its inactivation severely attenuates virulent mycobacteria. In this work, we show that clinical isolates ofM. tuberculosisproduce and secrete larger amounts of ESAT-6 than the widely usedM. tuberculosisH37Rv laboratory strain. A search for the genetic polymorphisms underlying this observation showed thatwhiB6(rv3862c), a gene upstream of the ESX-1 genetic locus that has not previously been found to be implicated in the regulation of the ESX-1 secretory apparatus, presents a unique single nucleotide insertion in its promoter region in strains H37Rv and H37Ra. This polymorphism is not present in any of the other publicly availableM. tuberculosiscomplex genomes or in any of the 76 clinicalM. tuberculosisisolates analyzed in our laboratory. We demonstrate that in consequence, the virulence master regulator PhoP downregulateswhiB6expression in H37Rv, while it upregulates its expression in clinical strains. Importantly, reintroduction of the wild-type (WT) copy ofwhiB6in H37Rv restored ESAT-6 production and secretion to the level of clinical strains. Hence, we provide clear evidence that inM. tuberculosis—with the exception of the H37Rv strain—ESX-1 expression is regulated by WhiB6 as part of the PhoP regulon, which adds another level of complexity to the regulation of ESAT-6 secretion with a potential role in virulence adaptation.
Exposure to Bacillus anthracis Capsule Results in Suppression of Human Monocyte-Derived Dendritic Cells
Authors: Jelacic Tanya M. , Chabot Donald J. , Bozue Joel A. , Tobery Steven A. , West Michael W. , Moody Krishna , Yang De , Oppenheim Joost J. , Friedlander Arthur M. 
Published: June 2014

ABSTRACTThe antiphagocytic capsule ofBacillus anthracisis a major virulence factor. We hypothesized that it may also mediate virulence through inhibition of the host's immune responses. During an infection, the capsule exists attached to the bacterial surface but also free in the host tissues. We sought to examine the impact of free capsule by assessing its effects on human monocytes and immature dendritic cells (iDCs). Human monocytes were differentiated into iDCs by interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) over 7 days in the presence of capsule derived from wild-type encapsulatedB. anthracisAmes (WT) or a control preparation from an isogenicB. anthracisAmes strain that produces only 2% of the capsule of the WT (capAmutant). WT capsule consistently induced release of IL-8 and IL-6 while thecapAmutant control preparation elicited either no response or only a minimal release of IL-8. iDCs that were differentiated in the presence of WT capsule had increased side scatter (SSC), a measure of cellular complexity, when assessed by flow cytometry. iDCs differentiated in the presence of WT capsule also matured less well in response to subsequentB. anthracispeptidoglycan (Ba PGN) exposure, with reduced upregulation of the chemokine receptor CCR7, reduced CCR7-dependent chemotaxis, and reduced release of certain cytokines. Exposure of naive differentiated control iDCs to WT capsule did not alter cell surface marker expression but did elicit IL-8. These results indicate that free capsule may contribute to the pathogenesis of anthrax by suppressing the responses of immune cells and interfering with the maturation of iDCs.