bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology of laser treated polycrystalline α-Al2O3
Authors: Shepeleva L. , Medres B. , Kaplan W. D. , Bamberger M. , Sharp C. M. , McCay M. H. , McCay T. D.
Published: September 2010

Applying metallic coating to ceramics via laser surface processing is an attractive process, due to the ability to reach relatively thick surface coatings, which include reaction products formed between the metal and ceramic. Two main effects must be characterized to implement such processes: damage to the ceramic due to thermal shock, and changes in the ceramic microstructure due to the process. This study focuses on the influence of laser surface processing on the microstructure of α-Al2O3. A CO2 laser with a maximum power of 3 kW was used for the study. The laser beam was scanned across the polycrystalline alumina substrate under argon at a rate of 0.66–2.0 cm/s. Specimens were prepared at laser powers ranging from 200 to 800 W, with a constant beam diameter of 0.2 cm. The substrates were preheated to 400 °C before the laser treatments to minimize thermal shock. The alumina substrates were 96% pure alumina plates, with a thickness of 2 mm. The microstructure within the melt pool varied strongly as a function of distance from the free surface. Different regions were identified by electron microscopy, with grain sizes varying from 2–3 μm up to 60 μm long needle-shaped grains having a {112̄6} preferred orientation with respect to the substrate surface. Due to the presence of Si, Ca, and Mg in the alumina, an amorphous phase was found at the grain boundaries throughout the melt-pool region. The amorphous phase primarily appeared as a relatively thin film at the grain boundaries. However, large spheres (≅ 50 μm) of amorphous regions also appeared in the melt pool, which contained small grains of alumina. The reasons for the strongly varying microstructure will be discussed.
Laser weld penetration monitoring with multiple emission signal measurements
Authors: Farson D. F. , Ali A. , Li X. C.
Published: September 2010

Classification of laser weld penetration based on measurements of selected process emissions was investigated. Optical, acoustic and charged particle emissions were measured during CO2 laser welding of thin sheet steel butt joints over a range of laser power and travel speed. The values of the operating parameters were chosen so as to produce both full and partial penetration welds. The various sensor signals were compared to each other and were found to be significantly (but not totally) correlated. The frequency spectra of the signals from the full and partial penetration welds were processed using linear discriminant analysis. This statistical technique is designed to separate data corresponding to different conditions, facilitating recognition of the different conditions from measured signals. It was found that linear discriminant analysis of combinations of the plasma charge plus acoustic signals as well as all three sensor signals in combination produced a good separation between signals from full and partial penetration welds. It was estimated that a laser weld monitor based on this approach would distinguish weld penetration condition with 88%–98% reliability.
Sensor systems for real-time monitoring of laser weld quality
Authors: Sun Allen , Kannatey-Asibu Elijah , Gartner Mark
Published: September 2010

On-line process monitoring is beneficial for maintaining high quality products at high production rates and low cost. Off-line traditional testing of welds can be costly in terms of time, material, and productivity. Real-time nondestructive testing, however, can be just as accurate as off-line testing; yet faster, cheaper, and increase productivity, when perfected for high volume repetitive applications. In the field of real-time monitoring, various sensors have shown promise in detecting weld states. These include acoustic emission, audible sound, infrared detectors, ultraviolet detectors, electromagnetic acoustic transducers, and polyvinylidene fluoride. Nevertheless, previous work indicates that no single sensor can reliably detect the full spectrum of weld states. As a result, sensor fusion has been investigated for integrating the advantages of individual sensors. This article presents a survey of technical information that is currently available in the literature, commercial systems, and patents, for real-time (laser) weld process monitoring. The focus is on the sensors listed above, along with multiple-sensor systems: dual wavelength infrared and ultraviolet, as well as audible sound and ultraviolet detection.
Nd:YAG laser drilling of 8.3 mm thick partially stabilized tetragonal zirconia-control of recast layer microcracking using localized heating techniques
Authors: Murray A. J. , Tyrer J. R.
Published: September 2010

The machining of ceramic components using conventional techniques is slow and expensive due to low yields. High power lasers are capable of machining these materials at far greater speeds. However, the performance of ceramic substrates is dependent on the quality of the processed region, with specific reference to the level of microcracking. The propagation of microcracks into the bulk substrate inevitably leads to component failure. Generation of recast layer microcracking is the Achilles heel of laser processing of ceramics. The fundamental process of laser radiation interaction with ceramic substrates generates a severe thermal gradient between the recast layer and bulk substrate. This in turn leads to the stresses which cause microcracks to form. Techniques for the reduction of this thermal shear have been investigated. Optimization of Nd:YAG laser drilling enabled repeatable and high quality processing to be undertaken. However, adaptation of these conventional techniques was required to reduce the level of recast layer microcracking. A method for the numerical characterization of microcracking was developed for this work and was based upon SEM image processing. The use of a high temperature furnace to heat substrates before and after laser processing reduced the level of recast layer microcracking by half, when compared to the ambient temperature process. However, sufficient microcracking was present to cause substrate failure. An unconventional plasma heating technique was developed and applied for the reduction of this cracking. For laser drilling at 1300 °C, the addition of localized plasma heating gave a further 14% mean reduction in recast layer microcracking. This advanced drilling technique also produced a 12% increase in mean hole diameter when compared to the furnace heating method.
Prediction of microstructures in laser welding of stainless steel AISI 304
Authors: Guo W. , Kar A.
Published: September 2010

A mathematical model is proposed to investigate the evolution of microstructures due to rapid solidification in laser materials processing. The instability of solid-liquid interface is analyzed by considering the diffusion process and perturbation method. The results of this model show that the neutral stability curve is largely dependent on solidification rate and partition coefficient. The decay, periodic oscillation, and growth of the perturbations at the solid-liquid interface can be regarded as planar, cellular and dendritic microstructures, respectively. Laser spot welding experiments were conducted for stainless steel AISI 304 to verify the theoretical predictions.
Update on ANSI Z136.1
Authors: Charschan Sidney S. , Rockwell Benjamin A.
Published: September 2010

Z136.1 Subcommittee Chairs, William P. Roach and Benjamin A. Rockwell, led the efforts culminating in a draft standard by the end of 1998 which revised and updated American National Standards Institute (ANSI) Z136.1-1993. This is now the fifth revision since 1973. This draft standard considers several major changes to revise laser hazard evaluation methods and laser classification for large sources. For collimated laser diode systems additional factors needed to be considered in order to maintain a fair margin of safety between the maximum permissable exposure (MPE) and actual injury thresholds for circular sources—with and without optically aided viewing. New data on ultrashort laser pulses (subnanosecond) changed the MPEs that were based on “constant power” criteria at 1 ns, while demonstrating new effects adversely impacting laser safety eyewear. Signs and labels are now more in accord with the latest ANSI Z535 and International Electrotechnical Commission recommendations.
Process optimization controller for robotic laser machining
Authors: Abdullah Hussein A. , Chatwin Chris R. , Seibi Abdennour C.
Published: September 2010

This work details the performance assessment of a high-bandwidth optical range sensor for local stand-off control of a robotically manipulated optical fiber laser beam delivery system. Consistent, repeatable high quality materials processing, using fiber optically delivered Nd3+-YAG laser radiation requires precise local control of stand-off distance. Unless specifically designed for laser processing applications, many robots produce a jerking incremental trajectory and usually suffer from position dependent displacement of the end effector. With the addition of a focal height servomechanism performance of the system can be considerably improved. The high-bandwidth optical range sensor described herein allows the use of such robots for fiber optically delivered laser beams enabling high quality laser cutting and welding operations using equipment that may already exist. Radiation from a low power laser diode is focused onto a workpiece surface; light reflected from the surface is collected through a main lens and directed into an astigmatic lens, which focuses the signal onto a quadrant photodiode. A differential amplifier is used to generate an output signal that determines the magnitude and direction of any workpiece displacement. The system facilitates a measuring range of ±5 mm; its effectiveness in controlling the stand-off distance for laser materials processing applications is assessed.
Study of an optical device for energy homogenization of a high power laser beam
Authors: Li JunChang , Lopes Rogério , Vialle Christine , Sacadura Jean-François
Published: September 2010

Using Fourier optic theory we have studied an optical device permitting the transformation of a high power laser beam into a quasihomogeneous square “spot.” We have compared theoretical results generated with software that we have developed to experimental results obtained using the optical device. Comparison shows good agreement between the two approaches.
Retinal laser accidents: mechanisms and management
Authors: Mainster Martin A.
Published: September 2010

Retinal injuries from industrial or military lasers are uncommon, but laser accidents can injure the retina and destroy central vision, permanently. Key principles of retinal anatomy and psychophysics provide a basis for understanding laser-retinal interactions, retinal trauma, and treatment options. Immediate vision loss after a laser accident depends primarily on the location and extent of retinal damage and vitreoretinal hemorrhage. Prompt ophthalmic evaluation of accident victims is indicated to determine the nature and severity of injuries to the cornea, iris, crystalline lens, and retina. There are no clinically proven therapies for minimizing the acute effects of retinal laser injuries, but vitreoretinal surgery is useful for managing complications such as persistent vitreous hemorrhages, macular holes, and epiretinal membranes. The best way to manage laser trauma is to prevent it.
Laser attenuation of the focused powder streams in coaxial laser cladding
Authors: Lin Jehnming
Published: September 2010

The optical attenuation of a laser beam passing through a powder stream during coaxial laser cladding has an important effect on the powder catchment efficiency for this new process. This attenuation for variations in the powder stream focus was studied both experimentally and theoretically in this article. Measurement of the laser attenuation caused by the streams was made to compare with the theoretical results. It shows that more than 50% of the laser energy could be lost in the powder stream and the focused stream gives less powder catchment than the nonfocused stream in coaxial laser cladding for 304 L stainless steel powder on mild steel with 1 kW CO2 laser radiation.
Laser bending of thin stainless steel sheets
Authors: Chan K. C. , Yau C. L. , Lee W. B.
Published: September 2010

In this article, a low power Nd:YAG laser is used to study the bending behavior of thin AISI 304 stainless steel sheets. It is observed that the bending angle decreases significantly with increasing material thickness, and that there exists a threshold heat input, below which no bending occurs. On the other hand, when the heat input is greater than a critical value, bending angle no longer increases with increasing heat input. A two-dimensional laser bending model is also developed to explain the deformation behavior. The trends of the predictions are in reasonable agreement with the experimental findings. These results are found to be significant in better understanding the deformation behavior of thin metal sheets in laser forming, and providing a basis for further investigation on laser forming of microdevices.
Safety eyewear requirements of United States and Europe
Authors: McLear Mark
Published: September 2010

Lasers have gone from a tool in the research area looking for an application to a necessity in the industrial workplace. Power levels continue to rise as new applications are developed. This poses increased risk of potential injury to the worker and a need for training on all forms of laser safety including the proper selection of personal protective equipment (PPE). With lasers, the single most important PPE is laser eyewear, however choosing the appropriate eyewear is often confusing and time consuming, This paper will attempt to simplify this process according to both the US standards (ANSI Z136.1) and the new European Norm 207.
Factors affecting the laser bending of Ti–6Al–2Sn–4Zr–2Mo
Authors: Marya M. , Edwards G. R.
Published: September 2010

The laser bending of near-α alloy Ti–6Al–2Sn–4Zr–2Mo sheets was investigated with a 1200 W Nd-YAG laser. The effect of scanning a material with a laser beam is to produce complex thermal cycles, which result in thermal stresses and angular deflections (bending angles). The conditions to promote large bending angles are first studied using an existing model of a moving Gaussian heat source. Analysis showed that bending could be explained from a characteristic temperature defined from material properties: the yield temperature. The morphology associated with its isotherm, which defines both the depth and the width of the yielded zone, adequately described bending. Optimal bending angles were observed when asymmetry of this yielded zone was maximum with respect to the neutral axis; i.e., before the yielded depth penetrated through the sheet thickness. The effects of repeated scans, such as the increases in bending angles, are also discussed together with the heat flow. With a three-dimensional heat flow, significant thickening occurred and sheet bendability decreased rapidly with repeated scans. The forming response was different when heat flow was more two dimensional. Although the asymmetry of the yielded zone was significantly reduced, bending angles were as large as earlier ones because of wider yielded zones. Also, thickening was barely observed, whereas bending rate continued to decrease. Causes of reduced bendability other than thickening are thus discussed. The expected contribution from transformations in microstructure was studied, but was not found to be significant.
Root vitality in the upper soil of pine stands ten years after thinning
Authors: Farfał Dorota
Published: September 2010

Żywotność korzeni w wierzchnich warstwach gleby w drzewostanach sosnowych w 10 lat po trzebieży
The abundance of the nun moth and lappet moth larvae on trees of different trunk thickness in Scots pine stands in the Noteć forest complex
Authors: Sukovata Lidia , Jaworski Tomasz
Published: September 2010

Liczebność gąsienic brudnicy mniszki i barczatki sosnówki na drzewach o różnej grubości w drzewostanach sosnowych Puszczy Noteckiej
Spatial differentiation of trees of different size classes in pine (Pinus sylvestris L.) stands with different initial densities
Authors: Szmyt Janusz , Zabielski Mariusz
Published: September 2010

Struktura przestrzenna drzew różnej grubości w drzewostanach sosnowych (Pinus sylvestrisL.) o różnym zagęszczeniu początkowym
The succession of saproxylic beetles (Coleoptera) on windthrow areas in the Scots pine stands of the Piska Forest
Authors: Gutowski Jerzy , Kubisz Daniel , Sućko Krzysztof , Zub Karol
Published: September 2010

Sukcesja saproksylicznych chrząszczy (Coleoptera) na powierzchniach pohuraganowych w drzewostanach sosnowych Puszczy Piskiej4
Changes in the volume and proportion of large-sized pine wood quality classes in relation to the type of log manipulation
Authors: Witkowska Joanna
Published: September 2010

Zmiany miąższości i udziału klas jakości drewna wielkowymiarowego sosnowego w zależności od rodzaju manipulacji dłużyc
August 2010 Letters to the Editor-in-Chief
Authors: Dorko Barrett L. , Falls Cuyahoga , Silvernail
Published: September 2010

Letters to the Editor-in-Chief of JOSPT as follows: ‘Manual Magic: The Method Is Not the Trick’ and Authors' Response ‘Moving Past Sleight of Hand’ and Authors' Response ‘Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises’ and Authors' Response J Orthop Sports Phys Ther 2010;40(8):535–541. doi:10.2519/jospt.2010.0201
Lower Thoracic Spine Pain in a 33-Year-Old Female
Authors: Robertson Eric K. , Evans Amanda L.
Published: September 2010

The patient was a 33-year-old woman with a chief complaint of midthoracic spine pain. Anterior-posterior and lateral radiographs of the thoracic spine revealed superior and inferior endplate deformities and a mild reduction of stature of the T9 vertebral body, which were suspicious for a fracture. Computed tomography scans revealed cortical irregularity of the vertebral body of T9, however, magnetic resonance imaging of the thoracic spine was negative. Given the magnetic resonance imaging findings, the smooth, well-defined cortical defect, and the absence of paraspinal hemorrhaging on the computed tomography scan, it was hypothesized that this may not have been an acute fracture. Rather, the cortical irregularity of the anterior vertebral body of T9 seen on computed tomography could have instead represented normal nutrient vascular channels. The patient was referred to an orthopaedic surgeon, who recommended conservative management by a physical therapist.

J Orthop Sports Phys Ther 2010;40(8):533. doi:10.2519/jospt.2010.0412
Juvenile Osteochondritis Dissecans of the Knee
Authors: Swain James H. , Grimm Nathan L. , Shea Kevin G.
Published: September 2010

The patient was a 13-year-old male soccer player who was referred to a physical therapist with complaints of persistent worsening left medial knee pain with weight-bearing activity. Physical examination revealed no signs of joint effusion, lower extremity range-of-motion or strength discrepancies, ligamentous compromise, or tenderness to palpation. However, the patient reported discomfort with weight bearing, and a slightly antalgic gait was observed. Knee radiographs revealed a concave lucency involving the medial femoral condyle, consistent with an osteochondritis dissecans lesion. Magnetic resonance imaging confirmed an osteochondritis dissecans lesion of the medial femoral condyle, and the patient was diagnosed with stage I juvenile osteochondritis dissecans of the knee. Conservative management by a physical therapist was the recommended treatment, and after 6 months, the patient no longer complained of left knee pain, and repeat knee radiographs demonstrated evidence of a healing osteochondritis dissecans lesion.

J Orthop Sports Phys Ther 2010;40(8):534. doi:10.2519/jospt.2010.0413
Comprehensive Impairment-Based Exercise and Manual Therapy Intervention for Patients With Subacromial Impingement Syndrome: A Case Series
Authors: Tate Angela R. , McClure Philip W. , Young Ian A. , Salvatori Renata , Michener Lori A.
Published: September 2010

Study Design

Case series.

Background

Few studies have defined the dosage and specific techniques of manual therapy and exercise for rehabilitation for patients with subacromial impingement syndrome. This case series describes a standardized treatment program for subacromial impingement syndrome and the time course and outcomes over a 12-week period.

Case Description

Ten patients (age range, 19–70 years) with subacromial impingement syndrome defined by inclusion and exclusion criteria were treated with a standardized protocol for 10 visits over 6 to 8 weeks. The protocol included a 3-phase progressive strengthening program, manual stretching, thrust and nonthrust manipulation to the shoulder and spine, patient education, activity modification, and a daily home exercise program of stretching and strengthening. Patients completed a history and measures of impairments and functional disability at 2, 4, 6, and 12 weeks.

Outcomes

Treatment success was defined as both a 50% improvement on the Disabilities of the Arm, Shoulder, and Hand (DASH) score and a global rating of change of at least “moderately better.” At 6 weeks, 6 of 10 patients had a successful (mean ± SD) DASH outcome score (initial, 33.9 ± 16.2; 6 weeks, 8.1 ± 9.2). At 12 weeks, 8 of 10 patients had a successful DASH outcome score (initial, 33.1 ± 14; 12 weeks, 8.3 ± 6.4). As a group, the largest improvement was in the first 2 weeks. The most common impairments for all 10 patients were rotator cuff and trapezius muscle weakness (10 of 10 patients), limited shoulder internal rotation motion (8 of 10 patients), and reduced kyphosis of the midthoracic area (7 of 10 patients).

Discussion

A program aimed at strengthening rotator cuff and scapular muscles, with stretching and manual therapy aimed at thoracic spine and the posterior and inferior soft-tissue structures of the glenohumeral joint appeared to be successful in the majority of patients. This case series describes a comprehensive impairment-based treatment which resulted in symptomatic and functional improvement in 8 of 10 patients in 6 to 12 weeks.

Level of Evidence

Therapy, level 4. J Orthop Sports Phys Ther 2010;40(8):474–493. doi:10.2519/jospt.2010.3223
The Effects of Thoracic Manipulation on Posteroanterior Spinal Stiffness
Authors: Campbell Brad D. , Snodgrass Suzanne J.
Published: September 2010

Study Design

Controlled laboratory study, with measurements taken before and after a standardized clinical intervention

Objectives

To determine if thoracic manipulation alters the posteroanterior (PA) spinal stiffness of the thoracic spine, and the factors associated with any potential changes in stiffness.

Background

Spinal manipulation is commonly used to treat thoracic pain and dysfunction. Therapists use manual assessment of PA spinal stiffness to determine the appropriateness and effectiveness of treatment, with potential changes in spinal stiffness possibly contributing to symptomatic improvement following manipulation.

Methods

Thoracic PA spinal stiffness was measured at 5 vertebral levels (manipulated level and 2 levels above and below), in 24 asymptomatic subjects, before and after manipulation. Five cycles of standardized mechanical PA force were applied to the spinous process while recording resistance to movement and concurrent displacement, with stiffness defined as the slope of the linear portion of the force-displacement curve. A 2-way repeated-measures analysis of variance determined differences between premanipulation and postmanipulation among multiple spinal levels. Linear regression determined the relationship between stiffness magnitude and its change following manipulation. Generalized linear mixed-models were used to determine if subject age, gender, spinal level, premanipulation stiffness, or manipulative thrust parameters were associated with postmanipulation stiffness.

Results

Thoracic spine PA stiffness differed between spinal levels (F4,92 = 21.1, P<.001) but was not significantly different following manipulation. The mean change in spinal stiffness correlated with stiffness magnitude at the manipulated spinal level only but not other levels (Pearson r, −0.65; P<.001). Greater postmanipulation stiffness was associated with being male (regression coefficient, 1.16; 95% CI: 0.52, 1.79; P<.001) and with higher premanipulation stiffness (regression coefficient, 0.63; 95% CI: 0.49, 0.77; P<.001). Manipulation force parameters were not associated with postmanipulation stiffness.

Conclusion

In asymptomatic individuals, thoracic PA spinal stiffness is not significantly different when measured before and after thrust manipulation, but any potential mechanical effects appear associated with the manipulated spinal level rather than other levels. J Orthop Sports Phys Ther 2010;40(11):685–693. doi:10.2519/jospt.2010.3271
Plasticity of Muscle Architecture After Supraspinatus Tears
Authors: Ward Samuel R. , Sarver Joseph J. , Eng Carolyn M. , Kwan Alan , Würgler-Hauri Carola C. , Perry Stephanie M. , Williams Gerald R. , Soslowsky Louis J. , Lieber Richard L.
Published: September 2010

Study Design

Controlled laboratory study.

Objectives

To measure the architectural properties of rat supraspinatus muscle after a complete detachment of its distal tendon.

Methods

Supraspinatus muscles were released from the left humerus of 29 Sprague-Dawley rats (mass, 400–450 g), and the animals were returned to cage activity for 2 weeks (n = 12), 4 weeks (n = 9), or 9 weeks (n = 8), before euthanasia. Measurements of muscle mass, pennation angle, fiber bundle length (sarcomere number), and sarcomere length permitted calculation of normalized fiber length, serial sarcomere number, and physiological cross-sectional area.

Results

Coronal oblique sections of the supraspinatus confirmed surgical transection of the supraspinatus muscle at 2 weeks, with reattachment by 4 weeks. Muscle mass and length were significantly lower in released muscles at 2 weeks, 4 weeks, and 9 weeks. Sarcomere lengths in released muscles were significantly shorter at 2 weeks but not different by 4 weeks. Sarcomere number was significantly reduced at 2 and 4 weeks, but returned to control values by 9 weeks. The opposing effects of smaller mass and shorter fibers produced significantly smaller physiological cross-sectional area at 2 weeks, but physiological cross-sectional area returned to control levels by 4 weeks.

Conclusions

Release of the supraspinatus muscle produced early radial and longitudinal atrophy of the muscle. The functional implications of these adaptations would be most profound at early time points (particularly relevant for rehabilitation), when the muscle remains smaller in cross-sectional area and, due to reduced sarcomere number, would be forced to operate over a wider range of the length-tension curve and at higher velocities, all adaptations resulting in compromised force-generating capacity. These data are relevant to physical therapy because they provide tissue-level insights into impaired muscle and shoulder function following rotator cuff injury. J Orthop Sports Phys Ther 2010;40(11):729–735. doi:10.2519/jospt.2010.3279
CEST and PARACEST MR contrast agents
Authors: Hancu Ileana , Dixon W. Thomas , Woods Mark , Vinogradov Elena , Sherry A. Dean , Lenkinski Robert E.
Published: September 2010

In this review we describe the status of development for a new class of magnetic resonance (MR) contrast agents, based on chemical exchange saturation transfer (CEST). The mathematics and physics relevant to the description of the CEST effect in MR are presented in an appendix published in the online version only. We discuss the issues arising when translating in vitro results obtained with CEST agents to using these MR agents in in vivo model studies and in humans. Examples are given on how these agents are imaged in vivo. We summarize the status of development of these CEST agents, and speculate about the next steps that may be taken towards the demonstration of CEST MR imaging in clinical applications.
Research and Implementation of Lane-Changing Model Based on Driver Behavior
Authors: Sun Daniel (Jian) , Elefteriadou Lily
Published: September 2010

Lane-changing algorithms have attracted increased attention during recent years. However, limited research has been conducted to address the probability of changing lanes and vehicle interactions that occur. The objective of this study is to model urban lane-changing maneuvers by using data related to driver behavior. Two components were developed from field data, for lane-changing probability and for gap acceptance. Two experiments were conducted to collect the corresponding lane-changing data: a focus group study and an in-vehicle driving test. The proposed lane-changing model was implemented in the CORSIM microscopic simulator. Traffic data collected from a busy arterial street were used for model calibration and validation, and the simulation capabilities of the newly developed model were compared with the original lane-changing model embedded in CORSIM. Results indicate that the new model replicates observed traffic under different levels of congestion better than the original model does.
Data Archives of Intelligent Transportation Systems Used to Support Traffic Simulation
Authors: Alvarez Patricio , Hadi Mohammed , Zhan Chengjun
Published: September 2010

Collecting data for traffic simulation is expensive, particularly for large simulated systems. When traditional methods are used, data are normally collected for only one day or a few days and may not represent variations in traffic demands and conditions throughout the year. Collected data usually are imperfect, and additional efforts are needed to compensate for missing and erroneous data and to resolve data inconsistencies. In recent years, agencies have started archiving data collected by intelligent transportation systems (ITS). The ITS data archives can provide cost-effective, detailed information for the development and calibration of simulation tools if procedures are used to ensure data quality and to allow optimal categorization and use of the archived ITS data. An effort to develop a series of data manipulation procedures for the use of ITS data archives in support of simulation modeling is discussed. These procedures allow the extraction of collected volume data from ITS data archives, automatic identification of temporal patterns in the data, automatic segmentation of daily demands into dynamically captured subperiods to best fit variations in demand, resolution of possible spatial inconsistencies in the data, and estimation of missing volumes. The developed procedures have been implemented as an automated tool for populating simulation models. The procedures and the developed tool can easily be adapted by other traffic agencies to interface with their ITS data archives.
Investigating the Shape of the Macroscopic Fundamental Diagram Using Simulation Data
Authors: Ji Yangbeibei , Daamen Winnie , Hoogendoorn Serge , Hoogendoorn-Lanser Sascha , Qian Xiaoyu
Published: September 2010

Macroscopic fundamental diagrams (MFDs) exist in large urban networks in which traffic conditions are homogenous. They can be used for estimation of the level of service on road networks, perimeter control, and macroscopic traffic modeling. However, before the MFD concept can be applied, the factors that influence the MFD shape should be identified and their effects investigated. A microscopic simulation model is used to change conditions, that is, to derive MFDs under different conditions and for different types of networks. Results indicate that a relationship indeed exists between production and accumulation for the whole network as well as for parts of the network focused on freeway or urban links. MFD shape is a property not only of the network itself but also of the applied traffic control measures. At the same time, congestion onset and resolution lead to heterogeneous traffic conditions with congestion at specific locations in the network, resulting in loops in congested parts of the MFD. Investigation of the effect of traffic demand on MFD also indicates that rapidly changing traffic demands drastically affect MFD shape.
Construcción de esculturas de hormigón con elementos procedentes del reciclado
Authors: Saval J. M. , Maciá A. , Ivorra S.
Published: September 2010

Este trabajo recoge el desarrollo conceptual, de proyecto, construcción y de ejecución de un conjunto de siete esculturas disenadas para actuar como contenedores de otras obras de arte (17 cuadros) realizadas por el artista Jesús Soler. Este conjunto escultórico basa su mensaje en la sostenibidad y el reciclaje. Presenta, como condiciones de contorno fundamentales, la capacidad de ser montado y desmontado sin necesidad de anclar al terreno, durabilidad y protección de las obras frente a agentes meteorológicos y todo ello transmitiendo por sí mismas un mensaje medioambiental. Se describe en el documento la geometría y proporciones basadas en el “Modulor” de Le Corbusier y, por consiguiente, en la sección áurea, así como todas las técnicas constructivas aplicadas para el correcto diseno de cada obra: sistemas de encofrado, hormigones con áridos reciclados, marcos de acero corten, anclajes, etc. Finalmente se describe el primer proceso de montaje de esta obra itinerante, en el Parque del Retiro de Madrid.
Cell Surface Heparan Sulfate Proteoglycans Influence MHC Class II-Restricted Antigen Presentation
Authors: Léonetti Michel , Gadzinski Adeline , Moine Gervaise
Published: September 2010

Heparan sulfate proteoglycans (HSPGs) are glycoproteins ubiquitously distributed on the cell surface and in the extracellular matrix. Their heparan sulfate moieties often represent alternative attachment points for extracellular proteins that target specific receptors. Thus, HSPGs modulate ligand–receptor encounters and participate in numerous biological processes. In this study, we examined whether HSPGs can also influence MHC class II-restricted Ag presentation. We selected a heparan sulfate ligand derived from the HIV-1 Tat protein and coupled it to a model protein Ag. We showed that coupling of the Tat fragment makes the Ag capable of binding cells, including APCs, and increases its ability to stimulate specific T cells up to 180-fold. The boosting effect depends on Ag processing; it vanished in the presence of an excess of heparin or free Tat fragment, indicating that HSPGs can behave as receptors involved in MHC class II processing and presentation. Furthermore, with FcγRII-bearing APCs, immune complexes containing the coupled Ag stimulated T cells up to 700-fold more efficiently than Ag-containing immune complexes. This effect vanished in the presence of heparin and is not found with FcγRII− APCs, indicating that HSPGs can also behave as coreceptors during FcγRIIR-mediated Ag presentation. These results indicate that ubiquitous receptors, such as HSPGs, can influence MHC class II-restricted Ag presentation and suggest that proteins will be supported more efficiently by the immune system if they have the inherent capacity to bind heparan sulfate.
The Origin and Maturity of Dendritic Cells Determine the Pattern of Sphingosine 1-Phosphate Receptors Expressed and Required for Efficient Migration
Authors: Rathinasamy Anchana , Czeloth Niklas , Pabst Oliver , Förster Reinhold , Bernhardt Günter
Published: September 2010

Dendritic cells (DCs) represent the most potent inducers of adaptive immune responses. Depending on their activation phenotype, DCs drive naive T cells into distinct differentiation pathways. To achieve this, DCs are present in virtually all tissues where they sample Ag and migrate to the T cell areas of lymph nodes (LNs) and spleen. Ample evidence exists demonstrating that sphingosine 1-phosphate (S1P) is an important modulator of these processes, exerting its effects by binding to the S1P receptor S1P1 and/or S1P3. However, published data are contradictory, in part. We show in this study that the expression pattern, as well as the regulation of the S1P receptors, differs among in vitro-generated DCs experiencing different kinds and duration of stimuli. Moreover, the influence of S1P1 and S1P3 on the in vivo migration of maturing DCs depends on the origin of these cells. Thus, in vitro-generated DCs require S1P1 and S1P3 to accomplish this, whereas skin-derived DCs migrate unhindered in the absence of S1P3 but not when S1P1 signaling is blocked. Migration of lamina propria DCs to the mesenteric LNs depends on S1P1 and S1P3. In contrast, relocation of maturing spleen-resident DCs to the T cell zone is independent of S1P1 and S1P3. However, intrasplenic positioning of immature DCs to the bridging channels depends on S1P1 activity, with no noticeable contribution of S1P3. These observations reveal a tissue-dependent contribution of S1P3 to DC migration and suggest a fundamental role for S1P1 for maturing DCs migrating from periphery to draining LNs.
Shedding of Large Functionally Active CD11/CD18 Integrin Complexes from Leukocyte Membranes during Synovial Inflammation Distinguishes Three Types of Arthritis through Differential Epitope Exposure
Authors: Gjelstrup Louise Carstensen , Boesen Thomas , Kragstrup Tue Wenzel , Jørgensen Annette , Klein Nigel J. , Thiel Steffen , Deleuran Bent Winding , Vorup-Jensen Thomas
Published: September 2010

CD18 integrins are adhesion molecules expressed on the cell surface of leukocytes and play a central role in the molecular mechanisms supporting leukocyte migration to zones of inflammation. Recently, it was discovered that CD11a/CD18 is shed from the leukocyte surface in models of inflammation. In this study, we show that shedding of human CD11/CD18 complexes is a part of synovial inflammation in rheumatoid arthritis and spondyloarthritis but not in osteoarthritis. In vivo and in vitro data suggest that the shedding is driven by TNF-α, which links the process to central events in the inflammatory response. The shed complexes contain multiple heterodimers of CD11/CD18, are variable in size, and differ according to the type of synovial inflammation. Furthermore, the differential structures determine the avidity of binding of the complexes to the ICAM-1. With the estimated concentrations of CD11/CD18 in plasma and synovial fluid a significant coverage of binding sites in ICAM-1 for CD18 integrins is expected. Based on cell adhesion experiments in vitro, we hypothesize that the large soluble complexes of CD11/CD18 act in vivo to buffer leukocyte adhesion by competing with the membrane-bound receptors for ICAM-1 binding sites. As reported here for synovial inflammation changes in the concentration or structure of these complexes should be considered as likely contributors to disease activity.
GB Virus Type C Envelope Protein E2 Elicits Antibodies That React with a Cellular Antigen on HIV-1 Particles and Neutralize Diverse HIV-1 Isolates
Authors: Mohr Emma L. , Xiang Jinhua , McLinden James H. , Kaufman Thomas M. , Chang Qing , Montefiori David C. , Klinzman Donna , Stapleton Jack T.
Published: September 2010

Broadly neutralizing Abs to HIV-1 are well described; however, identification of Ags that elicit these Abs has proven difficult. Persistent infection with GB virus type C (GBV-C) is associated with prolonged survival in HIV-1–infected individuals, and among those without HIV-1 viremia, the presence of Ab to GBV-C glycoprotein E2 is also associated with survival. GBV-C E2 protein inhibits HIV-1 entry, and an antigenic peptide within E2 interferes with gp41-induced membrane perturbations in vitro, suggesting the possibility of structural mimicry between GBV-C E2 protein and HIV-1 particles. Naturally occurring human and experimentally induced GBV-C E2 Abs were examined for their ability to neutralize infectious HIV-1 particles and HIV-1–enveloped pseudovirus particles. All GBV-C E2 Abs neutralized diverse isolates of HIV-1 with the exception of rabbit anti-peptide Abs raised against a synthetic GBV-C E2 peptide. Rabbit anti–GBV-C E2 Abs neutralized HIV-1–pseudotyped retrovirus particles but not HIV-1–pseudotyped vesicular stomatitis virus particles, and E2 Abs immune-precipitated HIV-1 gag particles containing the vesicular stomatitis virus type G envelope, HIV-1 envelope, GBV-C envelope, or no viral envelope. The Abs did not neutralize or immune-precipitate mumps or yellow fever viruses. Rabbit GBV-C E2 Abs inhibited HIV attachment to cells but did not inhibit entry following attachment. Taken together, these data indicate that the GBV-C E2 protein has a structural motif that elicits Abs that cross-react with a cellular Ag present on retrovirus particles, independent of HIV-1 envelope glycoproteins. The data provide evidence that a heterologous viral protein can induce HIV-1–neutralizing Abs.
Chow groups of K3 surfaces and spherical objects
Authors: Huybrechts Daniel
Published: September 2010

We show that for a K3 surface

X

the finitely generated subring

R (X) ⊂ \mathrm{CH}^* (X)

introduced by Beauville and Voisin is preserved under derived equivalences. This is proved by analyzing Chern characters of spherical bundles (and complexes). As for a K3 surface

X

defined over a number field all spherical bundles on the complex K3 surface

X_ℂ

are defined over

\bar ℚ

, this is compatible with the Bloch–Beilinson conjecture. Besides the work of Beauville and Voisin [5], Lazarfeld’s result on Brill–Noether theory for curves in K3 surfaces [15] and the deformation theory developed in [12] are central for the discussion.
A mesoproterozoic continental flood rhyolite province, the Gawler Ranges, Australia: the end member example of the Large Igneous Province clan
Authors: Pankhurst M. J. , Schaefer B. F. , Betts P. G. , Phillips N. , Hand M.
Published: September 2010

Abstract. Rhyolite and dacite lavas of the Mesoproterozoic upper Gawler Range Volcanics (GRV) (>30 000 km3 preserved), South Australia, represent the remnants of one of the most voluminous felsic magmatic events preserved on Earth. Geophysical interpretation suggests eruption from a central cluster of feeder vents which supplied large-scale lobate flows >100 km in length. Pigeonite inversion thermometers indicate eruption temperatures of 950–1100 °C. The lavas are A-type in composition (e.g. high Ga/Al ratios) and characterised by elevated primary halogen concentrations (~1600 ppm Fluorine, ~400 ppm Chlorine). These depolymerised the magma such that temperature-composition-volatile non-Arrhenian melt viscosity modelling suggests they had viscosities of <3.5 log η (Pa s). These physicochemical properties have led to the emplacement of a Large Rhyolite Province, which has affinities in emplacement style to Large Basaltic Provinces. The low viscosity of these felsic magmas has produced a unique igneous system on a scale which is either not present or poorly preserved elsewhere on the planet. The Gawler Range Volcanic Province represents the erupted portion of the felsic end member of the family of voluminous, rapidly emplaced terrestrial magmatic provinces.
Epigenetic profiling of the H19 differentially methylated region and comprehensive whole genome array‐based analysis in Silver–Russell syndrome
Authors: Lin Shin‐Yu , Lee Chien‐Nan , Hung Chia‐Cheng , Tsai Wen‐Yu , Lin Shuan‐Pei , Li Ni‐Chung , Hsieh Wu‐Shiun , Tung Yi‐Ching , Niu Dau‐Ming , Hsu Wen‐Ming , Chen Lang‐Yao , Fang Mei‐Ya , Tu Mei‐Pin , Kuo Pei‐Wen , Lin Chiou‐Ya , Su Yi‐Ning , Ho Hong‐Nerng
Published: September 2010

Silver–Russell syndrome (SRS) is a clinically and genetically heterogeneous congenital disorder characterized by severe growth retardation. Hypomethylation of the differentially methylated region (DMR) of the H19 gene and uniparental disomy of maternal chromosome 7 is present in ∼45% of the patients with SRS so more than half of these patients have no known genetic etiology. We combined several molecular technologies including multiplex methylation polymerase chain reaction, methylation‐sensitive multiple ligation probe‐dependent amplification, and methylation‐sensitive high‐resolution melting to assess the epigenetic status of 34 patients with SRS. Additionally, we applied a whole genome strategy to detect copy number changes and loss of heterozygosity. Thirteen patients (38.2%) had hypomethylation of the DMR of the H19 gene and none had uniparental disomy of maternal chromosome 7. The whole genome arrays identified five patients (14.7%) with microdeletions on chromosomes 1q23q24.3, 7p15.3, 13q31.3, 14q32.31, and 15q26.2qter, respectively. The overall mutation detection rate was 52.9% by the epigenetic study and the whole genome strategy. Although epimutation may be the major cause of SRS and can be identified by multiplex methylation polymerase chain reaction, the whole genome approach also provides information on the etiology of SRS. If no epimutation is identified in the patients with typical SRS, microdeletions should be suspected. © 2010 Wiley‐Liss, Inc.
Shells and heart: Are human laterality and chirality of snails controlled by the same maternal genes?
Authors: Oliverio Marco , Digilio Maria Cristina , Versacci Paolo , Dallapiccola Bruno , Marino Bruno
Published: September 2010

The body of most animals display left–right asymmetry of internal organs. Alteration of such asymmetry results in severe congenital defects particularly affecting the cardiovascular system. The earliest known genes involved in asymmetry, the Nodal signalling cascade, are expressed asymmetrically during embryonic development. Nodal was discovered in the mouse, but orthologs (also involved in left‐right specification) were reported in ascidians, sea‐urchins, and snails. Mutations in Nodal‐pathway genes cause alteration of several aspects of chirality, but not entirely mirror phenotypes of the body. Other factors upstream of nodal must be involved in the generation of left–right asymmetry. In snails, breeding experiments have demonstrated that chirality is controlled by a nuclear gene with maternal effect. Given the available evidence, we propose that an evolutionarily conserved genetic basis of chirality (the same that controls left–right asymmetry in snails) is a major synapomorphy of the Bilateria. This hypothesis fits with the observation that: (a) the proportion of patients with heterotaxy and a detected mutation in a gene of the Nodal cascade is actually low, and (b) horizontal recurrence of laterality defects is remarkably more frequent than vertical recurrence, and includes a notable number of affected sibs and/or repeated abortions from unaffected mothers. Identification of the maternal gene(s) involved will allow for the identification of homozygous females at risk of having affected children and spontaneous abortions, and would provide a general medical framework for understanding the genetics of most alterations of chirality. © 2010 Wiley‐Liss, Inc.
Mild phenotype in a patient with mosaic del(8p)/inv dup del(8p)
Authors: Hand Matthew , Gray Carolyn , Glew Gwen , Tsuchiya Karen D.
Published: September 2010

We report on a female with a mild phenotype who is mosaic for two cell lines with different structural abnormalities of 8p, both resulting in large genomic imbalances. Molecular cytogenetic and G‐banded chromosome analyses demonstrated that one cell line has a large terminal 8p deletion, with a breakpoint in 8p21.2. The other cell line contains a derivative chromosome 8, known as an inv dup del(8p) in the literature. This female has developmental delay, but lacks congenital anomalies that are associated with either 8p abnormality in non‐mosaic form. The attenuated phenotype in this individual may be due to compensation of one cell line for imbalances in the other cell line. © 2010 Wiley‐Liss, Inc.