bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards a Better Understanding of the Rail Grinding Mechanism
Authors: Zhi Shaodan , Zarembski Allan M. , Li Jianyong 
Published: February 2014

Rail grinding continues to be one of the most effective techniques for extending rail life, improving wheel/rail contact behavior, and reducing the overall cost of track maintenance. While the ability to more effectively implement improved rail grinding programs continues to expand, the understanding of the grinding mechanism itself has not kept pace with the improved implementation. Thus, while railroad engineering and maintenance personnel have learned to better develop grinding patterns and profiles through empirical testing and field evaluation, the fundamental theoretical bases for the improved grinding performance have not kept pace.
One such fundamental area of understanding is the modeling of the rail grinding process itself, both individually, as a function of a single grinding motor on the head of the rail, and in the more complex configuration of multiple grinding motors in a range of patterns. This paper presents the results of research directly aimed at better understanding these mechanisms and then utilizing this better understanding to develop a detailed rail grinding model that allows for the accurate analysis of not only an individual grinding motor but also a full grinding train application, as a function of pattern and speed.
In the case of the single grinding motor on the head of the rail, this research looks at the fundamental mechanism associated with each cutting abrasive grinding grain in the grinding stone, and then expands that mechanism to a full 10 inch diameter grinding wheel as it cuts into the rail head at a defined angle and speed. Using actual rail profile data and grinding data, a theoretical grinding wheel model is developed and then calibrated with wheel test data and actual grinding (field) data.
This single motor model is then expanded into a full grinding train model, such as for a 96 stone grinding train with 48 motors per rail, where it is able to analyze the full sequence of 48 motors as each motor individually and sequentially removes metal from the rail head. The resulting analysis is sensitive to such key factors as grinding speed, and the key pattern parameters of motor angles, sequence and power. The model is then calibrated to and compared with actual full scale rail grinding metal removal data from a major Class 1 railroad.
Such an analysis tool allows railroads to analyze the performance of different grinding patterns in a real world operating setting, to improve their rail grinding practices and take further advantage of new technologies in rail grinding to better manage the grinding process and improve planning of grinding activities.
Modern Uncertainty Quantification Methods in Railroad Vehicle Dynamics
Authors: Bigoni D. , Engsig-Karup A. P. , True H. 
Published: February 2014

This paper describes the results of the application of Uncertainty Quantification methods to a simple railroad vehicle dynamical example. Uncertainty Quantification methods take the probability distribution of the system parameters that stems from the parameter tolerances into account in the result. In this paper the methods are applied to a low-dimensional vehicle dynamical model composed by a two-axle truck that is connected to a car body by a lateral spring, a lateral damper and a torsional spring, all with linear characteristics.
Their characteristics are not deterministically defined, but they are defined by probability distributions. The model — but with deterministically defined parameters — was studied in [1] and [2], and this article will focus on the calculation of the critical speed of the model, when the distribution of the parameters is taken into account.
Results of the application of the traditional Monte Carlo sampling method will be compared with the results of the application of advanced Uncertainty Quantification methods [3]. The computational performance and fast convergence that result from the application of advanced Uncertainty Quantification methods is highlighted. Generalized Polynomial Chaos will be presented in the Collocation form with emphasis on the pros and cons of each of those approaches.
Improved Quality Truck Castings
Authors: Jones Kerry 
Published: February 2014

Component failure in bolsters and side frames remains a problem for both railroads and suppliers, causing expensive repairs and even derailments. To understand and combat this problem, an evaluation of the steel was required.
Bolsters were obtained from several suppliers to evaluate the current state of Association of American Railroads (AAR) M-201 standard for Grade B+ cast steel. Charpy impact and tensile test samples were machined from critical areas of these castings and tested at an independent laboratory. Distinct differences were found in processes and in mechanical properties between some suppliers. Supplier names are not identified in this paper.
Based on the chemical and mechanical testing results and data analysis, changes to AAR M-201 Grade B+ requirements have been proposed. Additional bolsters have been obtained for further testing. These bolsters will incorporate the proposed changes to the standard and the same mechanical testing will be performed on them to determine the effectiveness of the proposed changes. Full scale static or fatigue testing will be conducted on additional bolsters.
A survey of scrapped bolsters and side frames from several railcar producers and reclaim operations was conducted to determine the leading causes of failures of components removed from service. These results form the basis for a database that can be used to identify failure trends.
Human radiation dosimetry of 6‐[18F]FDG predicted from preclinical studies
Authors: Muzic Raymond F. , Chandramouli Visvanathan , Huang Hsuan‐Ming , Wu Chunying , Hatami Ahmad , Ismail‐Beigi Faramarz 
Published: February 2014

Purpose:The authors are developing 6‐[18F]fluoro‐6‐deoxy‐D‐glucose (6‐[18F]FDG) as an in vivo tracer of glucose transport. While 6‐[18F]FDG has the same radionuclide half‐life as 2‐[18F]fluoro‐2‐deoxy‐D‐glucose (2‐[18F]FDG) which is ubiquitously used for PET imaging, 6‐[18F]FDG has special biologic properties and different biodistributions that make it preferable to 2‐[18F]FDG for assessing glucose transport. In preparation for 6‐[18F]FDG use in human PET scanning, the authors would like to determine the amount of 6‐[18F]FDG to inject while maintaining radiation doses in a safe range.Methods:Rats were injected with 6‐[18F]FDG, euthanized at specified times, and tissues were collected and assayed for activity content. For each tissue sample, the percent of injected dose per gram was calculated and extrapolated to that for humans in order to construct predicted time‐courses. Residence times were calculated as areas under the curves and were used as inputs to OLINDA/EXM in order to calculate the radiation doses.Results:Unlike with 2‐[18F]FDG for which the urinary bladder wall receives the highest absorbed dose due to urinary excretion, with 6‐[18F]FDG there is little urinary excretion and osteogenic cells and the liver are predicted to receive the highest absorbed doses: 0.027 mGy/MBq (0.100 rad/mCi) and 0.018 mGy/MBq (0.066 rad/mCi), respectively. Also, the effective dose from 6‐[18F]FDG, i.e., 0.013 mSv/MBq (0.046 rem/mCi), is predicted to be approximately 30% lower than that from 2‐[18F]FDG.Conclusions:6‐[18F]FDG will be safe for use in the PET scanning of humans.
Long‐term stability of the Leksell Gamma Knife® Perfexion™ patient positioning system (PPS)
Authors: Novotny J. , Bhatnagar J. P. , Xu Y. , Huq M. S. 
Published: February 2014

Purpose:To assess the long‐term mechanical stability and accuracy of the patient positioning system (PPS) of the Leksell Gamma Knife® Perfexion™ (LGK PFX).Methods:The mechanical stability of the PPS of the LGK PFX was evaluated using measurements obtained between September 2007 and June 2011. Three methods were employed to measure the deviation of the coincidence of the radiological focus point (RFP) and the PPS calibration center point (CCP). In the first method, the onsite diode test tool with single diode detector was used together with the 4 mm collimator on a daily basis. In the second method, a service diode test tool with three diode detectors was used biannually at the time of the routine preventive maintenance. The test performed with the service diode test tool measured the deviations for all three collimators 4, 8, and 16 mm and also for three different positions of the PPS. The third method employed the conventional film pin‐prick method. This test was performed annually for the 4 mm collimator at the time of the routine annual QA. To estimate the effect of the patient weight on the performance of the PPS, the focus precision tests were also conducted with varying weights on the PPS using a set of lead bricks.Results:The average deviations measured from the 641 daily focus precision tests were 0.1 ± 0.1, 0.0 ± 0.0, and 0.0 ± 0.0 mm, respectively, for the 4 mm collimator in the X (left/right of the patient), Y (anterior/posterior of the patient), and Z (superior/inferior of the patient) directions. The average of the total radial deviations as measured during ten semiannual measurements with the service diode test tool were 0.070 ± 0.029, 0.060 ± 0.022, and 0.103 ± 0.028 mm, respectively for the central, long, and short diodes for the 4 mm collimator. Similarly, the average total radial deviations measured during the semiannual measurements for the 4, 8, and 16 mm collimators and using the central diode were 0.070 ± 0.029, 0.097 ± 0.025, 0.159 ± 0.028 mm, respectively. The average values of the deviations as obtained from the five annual film pin‐prick tests for the 4 mm collimator were 0.10 ± 0.06, 0.06 ± 0.09, and 0.03 ± 0.03 mm for the X, Y, Z stereotactic directions, respectively. Only a minor change was observed in the total radial deviations of the PPS as a function of the simulated patient weight up to 202 kg on the PPS.Conclusions:Excellent long‐term mechanical stability and high accuracy was observed for the PPS of the LGK PFX. No PPS recalibration or any adjustment in the PPS was needed during the monitored period of time. Similarly, the weight on the PPS did not cause any significant disturbance in the performance of the PPS for up to 202 kg simulated patient weight.
X‐ray scatter correction in breast tomosynthesis with a precomputed scatter map library
Authors: Feng Steve Si Jia , D'Orsi Carl J. , Newell Mary S. , Seidel Rebecca L. , Patel Bhavika , Sechopoulos Ioannis 
Published: February 2014

Purpose:To develop and evaluate the impact on lesion conspicuity of a software‐based x‐ray scatter correction algorithm for digital breast tomosynthesis (DBT) imaging into which a precomputed library of x‐ray scatter maps is incorporated.Methods:A previously developed model of compressed breast shapes undergoing mammography based on principal component analysis (PCA) was used to assemble 540 simulated breast volumes, of different shapes and sizes, undergoing DBT. A Monte Carlo (MC) simulation was used to generate the cranio‐caudal (CC) view DBT x‐ray scatter maps of these volumes, which were then assembled into a library. This library was incorporated into a previously developed software‐based x‐ray scatter correction, and the performance of this improved algorithm was evaluated with an observer study of 40 patient cases previously classified as BI‐RADS® 4 or 5, evenly divided between mass and microcalcification cases. Observers were presented with both the original images and the scatter corrected (SC) images side by side and asked to indicate their preference, on a scale from −5 to +5, in terms of lesion conspicuity and quality of diagnostic features. Scores were normalized such that a negative score indicates a preference for the original images, and a positive score indicates a preference for the SC images.Results:The scatter map library removes the time‐intensive MC simulation from the application of the scatter correction algorithm. While only one in four observers preferred the SC DBT images as a whole (combined mean score = 0.169 ± 0.37, p > 0.39), all observers exhibited a preference for the SC images when the lesion examined was a mass (1.06 ± 0.45, p < 0.0001). When the lesion examined consisted of microcalcification clusters, the observers exhibited a preference for the uncorrected images (−0.725 ± 0.51, p < 0.009).Conclusions:The incorporation of the x‐ray scatter map library into the scatter correction algorithm improves the efficiency of the algorithm. The observer study presented here is also the first test of the scatter correction algorithm with patient images and human observers, and demonstrates its potential to improve the clinical performance of DBT.
Solar Synthesis: Prospects in Visible Light Photocatalysis
Authors: Schultz Danielle M. , Yoon Tehshik P. 
Published: February 2014

Background
Interest in photochemical synthesis has been motivated in part by the realization that sunlight is effectively an inexhaustible energy source.Chemists have also long recognized distinctive patterns of reactivity that are uniquely accessible via photochemical activation. However, most simple organic molecules absorb only ultraviolet (UV) light and cannot be activated by the visible wavelengths that comprise most of the solar energy that reaches Earth’s surface. Consequently, organic photochemistry has generally required the use of UV light sources.

Advances
Over the past several years, there has been a resurgence of interest in synthetic photochemistry, based on the recognition that the transition metal chromophores that have been so productively exploited in the design of technologies for solar energy conversion can also convert visible light energy into useful chemical potential for synthetic purposes. Visible light enables productive photoreactions of compounds possessing weak bonds that are sensitive toward UV photodegradation. Furthermore, visible light photoreactions can be conducted by using essentially any source of white light, including sunlight, which obviates the need for specialized UV photoreactors. This feature has expanded the accessibility of photochemical reactions to a broader range of synthetic organic chemists. A variety of reaction types have now been shown to be amenable to visible light photocatalysis via photoinduced electron transfer to or from the transition metal chromophore, as well as energy-transfer processes. The predictable reactivity of the intermediates generated and the tolerance of the reaction conditions to a wide range of functional groups have enabled the application of these reactions to the synthesis of increasingly complex target molecules.

Outlook
This general strategy for the use of visible light in organic synthesis is already being adopted by a growing community of synthetic chemists. Much of the current research in this emerging area is geared toward the discovery of photochemical solutions for increasingly ambitious synthetic goals. Visible light photocatalysis is also attracting the attention of researchers in chemical biology, materials science, and drug discovery, who recognize that these reactions offer opportunities for innovation in areas beyond traditional organic synthesis. The long-term goals of this emerging area are to continue to improve efficiency and synthetic utility and to realize the long-standing goal of performing chemical synthesis using the sun.
Commentary: The Role of the Clinical Laboratory in the Future of Health Care: Lean Microbiology
Authors: Samuel Linoj , Novak-Weekley Susan 
Published: February 2014

ABSTRACT
This commentary will introduce lean concepts into the clinical microbiology laboratory. The practice of lean in the clinical microbiology laboratory can remove waste, increase efficiency, and reduce costs. Lean, Six Sigma, and other such management initiatives are useful tools and can provide dividends but must be accompanied by organizational leadership commitment to sustaining the lean culture in the laboratory setting and providing resources and time to work through the process.
Clinical Characteristics of Bacteremia Caused by Helicobacter cinaedi and Time Required for Blood Cultures To Become Positive
Authors: Araoka Hideki , Baba Masaru , Kimura Muneyoshi , Abe Masahiro , Inagawa Hiroko , Yoneyama Akiko 
Published: February 2014

ABSTRACTThe aim of this study was to clarify the clinical characteristics of patients withHelicobacter cinaedibacteremia and the time required for blood cultures to become positive. The medical records of all patients withH. cinaedibacteremia at Toranomon Hospital and Toranomon Hospital Kajigaya between March 2009 and March 2013 were retrospectively reviewed. Sixty-three patients, 34 men and 29 women with a median age of 67 years (range, 37 to 88 years), were diagnosed withH. cinaedibacteremia. A total of 51,272 sets of blood cultures were obtained during the study period, of which 5,769 sets of blood cultures were positive for some organism and 126 sets wereH. cinaedipositive. The time required for blood cultures to become positive forH. cinaediwas ≤5 days in 69 sets (55%) and >5 days in 57 sets (45%). Most patients had an underlying disease, including chronic kidney disease (21 cases), solid tumor (19 cases), hematological malignancy (13 cases), diabetes mellitus (8 cases), chronic liver disease (6 cases), and postorthopedic surgery (3 cases). Only 1 patient had no apparent underlying disease. The clinical symptoms included cellulitis in 24 cases, colitis in 7 cases, and fever only in 27 cases, including 7 cases of febrile neutropenia. The 30-day mortality rate ofH. cinaedibacteremia was 6.3%. In conclusion, most cases ofH. cinaedibacteremia occurred in immunocompromised patients. We might have overlooked nearly half of theH. cinaedibacteremia cases if the duration of monitored blood culture samples had been within 5 days. Therefore, when clinicians suspectH. cinaedibacteremia, the observation period for blood cultures should be extended.
Identification of Polybacterial Communities in Patients with Postoperative, Posttraumatic, and Endogenous Endophthalmitis through 16S rRNA Gene Libraries
Authors: Jayasudha Rajagopalaboopathi , Narendran Venkatapathy , Manikandan Palanisamy , Prabagaran Solai Ramatchandirane 
Published: February 2014

ABSTRACT

Endophthalmitis is a potential vision-threatening complication following surgical procedures (postoperative endophthalmitis [POE]), trauma (posttraumatic endophthalmitis [PTE]), and bacteremic seeding of the eye from a distant infection site (endogenous endophthalmitis [EE]). Several studies have revealed the polybacterial characteristics of endophthalmitis, which make the administration of antibiotics to treat the disease challenging. However, until now, the polybacterial communities of POE, PTE, and EE have not been precisely studied. Hence, the present study was designed to identify the bacterial community of endophthalmitis through 16S rRNA gene libraries. Of the 40 intraocular samples tested, 30 libraries were constructed with bacterial nested-PCR-positive samples. The obtained recombinant clones were screened through amplified rRNA gene restriction analysis (ARDRA) to identify unique clones. The multiple types of ARDRA patterns (
P
= 0.345) and diverse bacterial sequences (
P
= 0.277) within the libraries revealed the polybacterial nature of infection in POE, PTE, and EE. Moreover, to the best of our knowledge, this is the first report on polybacterial infection in EE. Gram-positive bacteria, including
Bacillus
spp. (
n
= 19),
Streptococcus
spp. (
n
= 18),
Staphylococcus
spp. (
n
= 6),
Exiguobacterium
spp. (
n
= 3),
Gemella
spp. (
n
= 2),
Enterococcus
spp. (
n
= 2), a
Lysinibacillus
sp. (
n
= 1), a
Clostridium
sp. (
n
= 1), and a
Nocardia
sp. (
n
= 1), and Gram-negative bacteria, including
Serratia
spp. (
n
= 18),
Pseudomonas
spp. (
n
= 10),
Enterobacter
spp. (
n
= 8),
Acinetobacter
spp. (
n
= 3),
Pantoea
spp. (
n
= 3), a
Haemophilus
sp. (
n
= 1), and a
Massilia
sp. (
n
= 1), were identified. Interestingly, among them, 10 bacterial species were not previously reported to be associated with endophthalmitis or other ocular infections. Besides, the presence of 4 unidentifiable clones suggests the possibility of novel organisms that might cause eye infections. Therefore, it is recommended that, in addition to the polybacterial nature of POE, PTE, and EE infections, the spectrum of the pathogenic bacterial community identified in this work should be considered while administering antibiotic therapy in suspected endophthalmitis cases.
Meta-Analysis of Sonication Fluid Samples from Prosthetic Components for Diagnosis of Infection after Total Joint Arthroplasty
Authors: Zhai Zanjing , Li Haowei , Qin An , Liu Guangwang , Liu Xuqiang , Wu Chuanlong , Li Huiwu , Zhu Zhenan , Qu Xinhua , Dai Kerong 
Published: February 2014

ABSTRACT
This meta-analysis included 12 studies that evaluated sonication fluid cultures (SFC) for the diagnosis of prosthetic joint infection (PJI). The pooled sensitivity and specificity were 0.80 (95% confidence interval [CI], 0.74 to 0.84) and 0.95 (CI, 0.90 to 0.98), respectively. Subgroup analyses showed that a 14-day anaerobic culture may improve sensitivity, the use of centrifugation or vortexing may improve specificity, and the use of 400 to 500 ml of Ringer's solution for containers may improve sensitivity and specificity. The best SFC cutoff was ≥5 CFU. In conclusion, SFC has high sensitivity and very high specificity for diagnosing PJI.
Direct Detection of Macrolide Resistance in Mycoplasma genitalium Isolates from Clinical Specimens from France by Use of Real-Time PCR and Melting Curve Analysis
Authors: Touati Arabella , Peuchant Olivia , Jensen Jorgen S. , Bébéar Cécile , Pereyre Sabine 
Published: February 2014

ABSTRACT

Mycoplasma genitalium
is a sexually transmitted organism commonly treated with azithromycin. However, macrolide resistance has been reported and is associated with point mutations in the 23S rRNA gene. To evaluate the prevalence of macrolide resistance in
M. genitalium
isolates from clinical specimens from France, we first used a previously reported high-resolution melting assay. Because susceptible and resistant
M. genitalium
isolates were hardly discriminated in
M. genitalium
-positive clinical specimens, we developed a new molecular assay for the rapid detection of macrolide resistance. An assay using real-time PCR based on fluorescence resonance energy transfer (FRET) coupled with melting curve analysis was designed. The assay was first validated on characterized macrolide-resistant
M. genitalium
isolates and then applied to 202 urogenital
M. genitalium
-positive specimens collected from 178 patients from France in 2011 and 2012. Resistant genotypes were confirmed by 23S rRNA gene sequencing. Among the 202
M. genitalium
-positive specimens, 155 were amplified, demonstrating a sensitivity of 76.7%. A substitution in the 23S rRNA gene was found in 14.2% of the patient samples. Nine and six patients had
M. genitalium
isolates with a substitution at positions 2059 and 2058, respectively. In four cases, a mixed population of wild-type and mutated
M. genitalium
isolates was observed. The prevalence of
M. genitalium
macrolide resistance has been stable in France since its detection in 2006. Our FRET PCR assay is able to discriminate between wild-type and resistant genotypes directly from clinical specimens. This assay will allow clinicians to shorten the time to the initiation of effective disease treatment.