bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental Implications of Cured-in-Place Pipe Rehabilitation Technology
Authors: Donaldson Bridget M.
Published: December 2009

Cured-in-place pipe (CIPP) technology is commonly used for pipe rehabilitation, and transportation agencies are increasingly using it to repair damaged pipe culverts. In typical CIPP applications, a lining tube saturated with a styrene-based thermosetting resin is installed into the damaged pipe. Subsequent curing with a heat source results in a pipe within a pipe. In this study, seven styrene-based, steam-cured CIPP installations in surface water and storm water conveyances in Virginia were identified and observed over the course of 1 year. Although the sites were not directly linked to sources of drinking water, styrene levels at five sites were higher than the Environmental Protection Agency's maximum contaminant level for drinking water of 0.1 mg/L. These concentrations were detected at these sites for a minimum of 5 days to 71 days after installation. Certain measurements were also found to exceed the concentration required to kill 50% of several freshwater aquatic indicator species. The findings suggest that the elevated styrene levels could have resulted from one or a combination of the following: ( a) installation practices that did not capture condensate containing styrene, ( b) uncured resin that escaped from the liner during installation, ( c) insufficient curing of the resin, and ( d) some degree of permeability in the lining material. In response to the preliminary findings of this study, the Virginia Department of Transportation suspended the use of styrene CIPP for conveying surface or storm water while the department further evaluated CIPP repair and subsequently developed new requirements for these installations.
Numerical Investigation of Stop-and-Go Traffic Patterns Upstream of Freeway Lane Drop
Authors: Zhang H. M. , Shen Wei
Published: December 2009

Freeway lane drops are typical sites where long queues and stop–start traffic waves can be observed. A theory was recently developed to explain the formation of traffic oscillations upstream of a freeway lane drop-in. Using that theory, this paper carries out a numerical investigation to explore how parameters characterizing the driving behavior at and the geometry of a lane-drop site may affect these oscillatory patterns. The effects of five factors–-distance between the merging sign and the taper, travel demand, remaining capacity, overall aggressiveness of drivers, and geometry of the lane drop–-are studied. It is found that a lane-drop site with low remaining capacity, high travel demand, short distance between the merging sign and the taper, closely matching numbers of drivers desiring to take the through lanes and to take the shoulder lanes, and an imbalance in merging priorities at the taper location is most likely to produce oscillations with short periods and high oscillation amplitudes in flow. Furthermore, the speeds at which the oscillations propagate and the periods of oscillations are in the same order of magnitude as those observed and can be made to match the observed values closely with the proper choice of parameters. Potential management measures to alleviate or eliminate such oscillations are also discussed.
Automated Analysis of Cumulative Flow and Speed Curves
Authors: Banks James H.
Published: December 2009

An automated procedure for analyzing cumulative flow and speed curves is described. The essential features of this method are a routine that uses a piecewise linear approximation to identify times that speed or flow changes and a set of rules to identify periods of queue discharge flow (QDF) and prequeue flow (PQF). These rules are based on speed thresholds, the duration of periods of low speed, the times congested flow is observed at different locations relative to the bottleneck, and (in the case of PQF) the regression slope of flow versus time. Results of the automated analysis are compared with those of a previous manual analysis of data from 21 bottlenecks. The automated analysis identified more, but shorter, periods of QDF than did the manual analysis, primarily because it was more likely to identify very short periods of QDF or recovery from congestion, but fewer and longer periods of PQF. Average flow for automatically identified periods of QDF was similar to that of manually identified periods, but average flow for automatically identified periods of PQF was almost always lower than that for those identified manually.
Reliability of Parameter Values Estimated Using Trajectory Observations
Authors: Ossen Saskia , Hoogendoorn Serge P.
Published: December 2009

Parameter values obtained by calibrating a car-following model using trajectory observations can provide important new insights into longitudinal driving behavior that cannot be derived from double loop detector data. However, that holds only if these behavioral parameters can be reliably estimated. This important aspect of calibration has been generally neglected in scientific research. In this contribution, therefore, calibrations are done to analyze several aspects influencing the degree to which behavioral parameters can be reliably estimated. In these calibrations trajectory data created by the authors with known characteristics as well as empirical trajectories are used. It is shown that traffic conditions during observation determine which model parameters can be reliably estimated. That measurement errors do negatively influence the reliability of parameter estimates is also demonstrated. The same negative effect appears to occur when a car-following model not fully able to capture the dynamics of the observed driver is calibrated. Finally, it is found that the extent to which a specific parameter can be reliably estimated is dependent on the degree to which it affects model predictions and thereby the value of the calibration objective. From this contribution it is concluded that to answer a specific research question on longitudinal driving behavior, it is essential to collect trajectories during appropriate traffic conditions. The results furthermore stress that even when trajectories contain enough information to calibrate the behavioral parameters of interest, whether it is reliable enough to draw inferences on car-following behavior needs to be determined for every parameter value separately.
Modeling Acceleration Decisions for Freeway Merges
Authors: Choudhury Charisma F. , Ramanujam Varun , Ben-Akiva Moshe E.
Published: December 2009

In uncongested traffic situations, a merge is executed when the available gap is sufficiently large. However, in congested traffic, acceptable gaps for merging are often not readily available, and merging can involve more complex mechanisms. For example, the driver in the target lane may slow down and cooperate with the merging driver, or the merging driver may become impatient and decide to force in, and compel the lag driver in the target lane to slow down. Choices of the merging plan or tactic affect the gap acceptance and acceleration decisions of the driver. A driver who has decided to force in, for instance, is likely to accept smaller gaps and accelerate to facilitate the merge. The chosen tactic at any instant, however, is not distinctly observable from the vehicle trajectory. The model presented in this paper extends previous research in modeling the effect of merging plans in the lane-changing decisions by integrating the acceleration decisions of the driver with the gap acceptance decisions. A combined model for merging plan choice, gap acceptance, target gap selection, and acceleration decisions of drivers merging from the on-ramp is developed in that regard. Parameters of all components of the models are estimated jointly with detailed vehicle trajectory data collected from Interstate 80 in California. The inclusion of the target gap choice and acceleration behavior components has been supported by a validation case study in which the model has been implemented in MITSIMLab and validated against the observed aggregate traffic data collected from US-101 in California.
State Dependence in Lane-Changing Models
Authors: Toledo Tomer , Katz Romina
Published: December 2009

Lane changes have a substantial impact on traffic flow characteristics. The lane-changing model is therefore an important element in microscopic traffic simulations. Lane changing is commonly modeled in two steps: lane choice, which captures the desire to change lanes, and the decision about whether a desired lane change can be completed, which is captured by gap acceptance models. Most current models assume that these decisions are repeated at every time step of the simulation independently of previous decisions. However, it may be more realistic to assume that drivers persist in their lane choices, and so their desired lane at any time point depends on earlier choices. To capture persistency in lane-changing behavior, a model that integrates a hidden Markov model (HMM) structure is presented. The evolution of lane choices, which are the underlying hidden states, is modeled using a Markovian process. The observed lane-changing actions depend on these hidden lane choices. An important difficulty that arises with this model structure is the problem of unobserved initial conditions on the hidden states. A method to address this problem is proposed. Estimation results of the resulting model are presented and compared with a model that does not incorporate state dependence.
Life in the Fast Lane
Authors: Hamdar Samer H. , Mahmassani Hani S.
Published: December 2009

The objective of this paper is to explore driver behavior in separate lane groups from a duration perspective by using hazard-based models. Driving is a continuous story divided into different experienced episodes. Each episode is terminated probabilistically on the basis of the surrounding traffic conditions as well as the drivers’ characteristics. This termination reflects mainly lane-changing behaviors. By means of the next generation simulation (NGSIM) trajectory data, an analysis is performed of the time durations until lane-changing maneuvers are executed. The distributions of such durations are found to be lane specific in cases in which the leftmost lanes show higher duration mean than the rightmost lanes. This indicates that drivers wait longer before deciding to change lanes in the leftmost lanes. In the middle lanes a bipeak distribution constitutes a transition between satisfaction in traveling in the fast lanes (left) versus impatience while traveling in the slower lanes (right).
Macroscopic Effects of Multianticipative Driving Behavior on Traffic Flow Characteristics
Authors: Ngoduy D.
Published: December 2009

Intelligent transportation systems have been considered an important solution in enhancing freeway capacity and suppressing traffic congestion. One recent automotive technology has enabled a vehicle to communicate with several vehicles ahead via a wireless system. Such a communication system constitutes so-called multianticipative driving behavior. In general, the effect of multianticipative interactions on traffic flow dynamics has been studied widely in the literature on the basis of a microscopic modeling approach. This paper presents an alternative approach to gain insights into the effect of multianticipative driving behavior on traffic flow characteristics from a macroscopic model. The model is obtained from a gas-kinetic theory in which the multianticipative interactions are taken into consideration. It is found that the analytical and numerical results of the model are consistent with those obtained from microscopic models. It is argued that the results provide a better understanding of the effect of multianticipative interactions on traffic flow characteristics.
Procedure for Calibrating Gipps Car-Following Model
Authors: Rakha Hesham , Wang Weidong
Published: December 2009

The research presented in this paper develops a procedure for calibrating the Gipps car-following model. The calibration procedure first entails calibrating the steady state car-following model using macroscopic loop detector data. Subsequently, the Gipps vehicle acceleration component is calibrated using vehicle specification data that can be easily obtained from automobile manufacturers. The calibration procedures were demonstrated to be valid using sample light-duty and heavy-duty vehicle field data. Furthermore, the Gipps acceleration model is demonstrated to be consistent with field observations for light-duty vehicle acceleration modeling. In the case of heavy-duty truck acceleration modeling, the Gipps model tends to overestimate vehicle speeds for heavy truck loadings (weight-to-power ratio in excess of 150 kg/kW).
Exploring the Impact of Homogeneity of Traffic Measurements on the Existence of Macroscopic Fundamental Diagrams
Authors: Buisson Christine , Ladier Cyril
Published: December 2009

Recently, some authors have provided experimental evidence of the existence of an urban-scale macroscopic fundamental diagram (MFD). Their convincing results were obtained on the basis of 500 urban fixed detectors placed 100 m upstream of most major intersections in the city of Yokohama, Japan. Those authors assume that the network in which data are collected is homogeneous in regard to congestion occurrence. This paper is devoted to exploring the impact of heterogeneity on the existence of an MFD. All data available for a medium-size French city are used. The data set encompasses measurements on highways, urban center streets (congested during business hours), and residential area streets. Data were collected by loop detectors with a distance from a downstream signal that can vary from 1,000 to 10 m. Heterogeneity is examined here in various aspects: differences between the surface and highway network, impact of the distance between the loop detector and the traffic signal in the surface network, and differences between penetrating roads and the ring road in the highway network. It is proved in this paper that heterogeneity has a strong impact on the shape of the macroscopic fundamental diagram.
Effects of Heterogeneity on Self-Organized Pedestrian Flows
Authors: Campanella Mario , Hoogendoorn Serge P. , Daamen Winnie
Published: December 2009

This investigation focuses on how the heterogeneity of pedestrian characteristics influences the buildup of congestion and affects the efficiency of pedestrian flows. Three commonly used parameters in pedestrian models–-desired speed, body size, and reaction time–-were varied in the population. Real pedestrian flows are heterogeneous regarding pedestrian characteristics. However, not much is known about the way that affects the qualities of the flow and how important it is to the outcomes of microsimulation models. The NOMAD model developed by Delft University of Technology is used to perform simulations in which the aforementioned heterogeneity is introduced. The investigation was carried out by creating bidirectional flows with fixed demands. The flows were analyzed by observing the development of breakdowns, average speeds, and average densities for different demands. It is shown that the influence of heterogeneity on breakdown probabilities and flow efficiency is considerable. To investigate this further, the dynamic lane formation process is investigated in detail. In addition to further insights into the causes for breakdown, it is found that the number of lanes increases with the decrease in heterogeneity in desired speed and in body size. However the opposite happens for heterogeneity in reaction time. Results indicate that heterogeneity in the population has a large impact on the flow quality and should be included in models explicitly to improve prediction performance.
Influence of Various Restrictions on Speed–Flow Models
Authors: Tracz Marian , Gaca Stanisław
Published: December 2009

This paper presents traffic speed models developed on the basis of numerous measurements. In studies of the speed–flow relationships the following research issues were analyzed: impacts of the speed limit, traffic flow, traffic flow composition, and time of day on speed–flow and impacts of qualitative road and roadside features (cross sections, road function, accessibility, intensity of development, roadside pedestrian traffic) on free-flow speed. The research included road sections with numerous constraints of traffic freedom. Such sections include sections of roads through built-up areas (small communities and towns). Regression analysis using generalized multiple regression was the basic tool in investigations. In addition, in analyzing data from speed measurements, the classic form of the logit function for a multiple-valued regression was applied. The analyses showed that even at general and posted speed limits the characteristic traffic flow–speed relations can be identified. The shape of these relations is characteristic of empirical results in which the spread of recorded values is typical for randomness and impacts of local factors. Average speed in traffic flow depends not only on geometric alignment of a road cross section but also on local factors and speed limits. Speed in free-flow traffic is significantly influenced by qualitative road and roadside characteristics. Most important of these factors are type of cross section, intensity of roadside development, and accessibility of the road.
Analysis of Traffic Flow Characteristics on Ring Road Expressways in Beijing
Authors: Zhao Nale , Yu Lei , Zhao Hui , Guo Jifu , Wen Huimin
Published: December 2009

The primary objective of this paper is to analyze traffic flow characteristics on ring road expressways in Beijing on the basis of floating car data (FCD) and remote traffic microwave sensors (RTMS) data. Traffic flow characteristics are studied in relation to lane use, the relationship between occupancy and density, relationship of flow–speed–density, and the relationship between FCD speed and RTMS speed. It is demonstrated that lane use characteristics on the basic sections of ring road expressways are similar to those of freeways, in which the average vehicle lengths in the median, center, and shoulder lanes are found to be approximately 5.78 m, 6.03 m, and 6.33 m, respectively. Further, the four essential parameters used to characterize the Van Aerde flow–speed–density relationship are calibrated and compared for the second, third, and fourth ring road expressways. Results indicate that the fourth ring road, which has the highest free-flow speed, speed-at-capacity, and capacity, has characteristics similar to those of typical freeways. Traffic flow characteristics observed on the second and third ring roads are roughly consistent with the Greenshields model. It is observed that the second ring road has the worst traffic conditions, followed by the third ring road, and that the basic sections of ring road expressways have better traffic conditions than the areas around the ramp junctions. Finally, a regression analysis is done to develop the relationship between FCD speed and RTMS speed. It is found that RTMS speed is slightly higher than FCD speed, with a difference of less than 6%.
Some Observed Features of Freeway Traffic Oscillations
Authors: Şahin İsmail
Published: December 2009

Some recent published works on freeway traffic have focused on congested traffic conditions in which oscillations form and propagate upstream through vehicle queues. Some features of oscillating waves were examined through empirical evidence. The data measured on multiple days along an approximately 3.5-km three-lane freeway in Istanbul, Turkey, present pronounced features of oscillations, such as their formation, propagation, and growth. It was identified that oscillations form immediately upstream of a bottleneck, they propagate at certain speeds against the direction of traffic flow, and their amplitude grows while propagating. In reports published earlier, it was stated that oscillating waves propagate backward at nearly constant speed with no dependence on flow. It has been observed in this study that propagation speeds cluster into two groups with averages of 21.29 and 15.52 km/h at the downstream and upstream study segments, respectively. It was shown that any difference in propagation speeds may be attributable to the features of the segment studied and, in turn, to the slope of the congested part of the associated fundamental diagram. A theory on reduction of oscillation amplitude at merge sites proposed in the literature was tested, and predictions of the theory were validated with some acceptable error.
Evolution of Oscillations in Congested Traffic
Authors: Laval Jorge , Chen Danjue , Amer Karim Ben , Guin Angshuman , Ahn Soyoung
Published: December 2009

This paper provides additional empirical evidence confirming a recently proposed theory on the evolution of oscillations in congested traffic. It also proposes an improved method for computing the variation in oscillation amplitude, consisting in evaluating the oscillation amplitude along characteristic lines that travel at a constant wave speed. It is also shown that the theory is robust in that approximate input parameters can be used with little loss in accuracy. The paper, in addition, provides a finding on the evolution of oscillations in freeway segments with no entrances or exits. Although previous studies found an increase in oscillation amplitude in such segments, data in this study indicate that this is not the case in general. This finding can have important implications for understanding driver behavior in homogeneous freeway segments.
Flow Breakdown and Travel Time Reliability
Authors: Dong Jing , Mahmassani Hani S.
Published: December 2009

This paper proposes a methodology for online prediction of travel time reliability based on real-world measurements in light of the probabilistic character of traffic breakdown. A discrete time Markov chain is developed to represent the flow breakdown event. Through the calibrated transition probability matrix of the Markov chain, the probability of flow breakdown or recovery along a given facility can be estimated. Travel time reliability that captures the probability of flow breakdown and the conditional expected delay associated with occurrence of breakdown can therefore be predicted. Because both the mean and the variance of travel time are represented as functions of current traffic conditions and calibrated for each road section on the basis of field data, travel time and its reliability could be obtained offline by analyzing historical data and computed online when real-time measurements are available.
Fundamental Diagram of Traffic Flows on Urban Roads
Authors: Wagner Peter , Brockfeld Elmar , Gartner Nathan H. , Sohr Alexander
Published: December 2009

Fundamental diagrams of traffic flow variables have been quite useful in determining freeway operations quality. However, they are usually not used for that purpose on urban roads. This work is an approach toward utilizing the fundamental diagram on urban roads. On the basis of a host of empirical and simulation work, the first steps toward a routine application of the fundamental diagram are sketched. In addition, two approaches are compared, the first uses a traditional fundamental diagram as measured by loop detectors, and the second uses a whole-link approach relating link–travel–speed with volume. The travel times in particular, contain important information that can be used for traffic management applications.
Vehicle Type–Specific Headway Analysis Using Freeway Traffic Data
Authors: Ye Fan , Zhang Yunlong
Published: December 2009

The distribution of time headway has long been a research topic because headway between vehicles is an important flow characteristic affecting safety, level of service, driver behavior, and capacity of a transportation system. However, almost all reported research on headway is focused on mixed vehicular flow without considering the difference in headway with respect to different vehicle types. In this paper, with the use of 1-day freeway traffic data from Interstate 35 in Austin, Texas, four time headway types based on different combinations of leading vehicles and following vehicles–-car–truck, truck–car, truck–truck, and car–car–-are analyzed at different traffic flow levels. Statistical comparisons between each vehicle type–specific headway and mixed vehicle–type headway are made to verify their significant differences. The paper demonstrates the necessity of vehicle type–specific headway study. The results of the paper not only identify qualitative differences between the vehicle type–specific headways and distributions, but also can be used as a reference for practical applications, especially for improving microscopic traffic simulation models.
A Cell Transmission Model with Lane Changing and Vehicle Tracking for Port of Entry Simulations
Authors: Cheu Ruey Long , Martinez Jorge , Duran Carlos
Published: December 2009

This paper presents a cell transmission model with a lane-changing and vehicle-tracking (CTM-LV) framework for simulation of international land ports of entry (POEs). The development of the modeling framework is motivated by the need to simulate lane-specific queuing yet permit lane changing of vehicles between queues–-a behavior that was not accounted for or tested by the earlier cell transmission models and that cannot be easily replicated in microscopic traffic simulation models. The CTM-LV's network representation, traffic flow logic, and lane-changing rules are discussed. A simulation experiment is then presented to illustrate the importance of modeling the lane changing between queues that will affect the estimation of average queue length. The concept of CTM-LV has been applied to simulate the northbound traffic at the Bridge of the Americas POE, for passenger cars entering El Paso, Texas, from Ciudad Juarez, Mexico. Finally, a method is proposed to track selected vehicles within the CTM-LV framework so that an individual vehicle's travel time can be calculated and vehicle trajectories compared against data collected by probe vehicles with Global Positioning System receivers.
Liquid–Liquid Equilibrium Constant for Acetic Acid in an Epoxidized Soybean Oil–Acetic Acid–Water System
Authors: Janković Milovan , Sinadinović‐Fišer Snežana , Lamshoeft Marc
Published: December 2009

Dependency of the liquid–liquid equilibrium constant for acetic acid (A) in a system of epoxidized soybean oil–acetic acid–water from temperature and composition was experimentally determined. To estimate the liquid–liquid equilibrium constant for acetic acid (KA), the interaction parameters of the Wilson, NRTL (non‐random two liquid) and UNIQUAC (universal quasi chemical) models for the activity coefficient were calculated by fitting the experimental values of the equilibrium constant for acetic acid. The Marquardt method was used to fit the data. In spite of all applied simplifications, small deviations of the calculated values from those experimentally determined indicate the adequacy of all three models for the prediction of the liquid–liquid equilibrium constant for acetic acid. Comparison of the experimentally determined values of the equilibrium constant for acetic acid in the investigated system with those reported in the literature for the system with soybean oil, shows that the value of the liquid–liquid equilibrium constant for acetic aid in the system of epoxidized soybean oil–acetic acid–water is about 1.5 times higher than in the system of soybean oil–acetic acid–water for the same temperature and similar composition. For the investigated conditions, the influence of the changing of the oil phase composition on the equilibrium constant for acetic acid is more prominent than the influence of the temperature or the total acetic acid content in the system.
Factors defining care‐seeking in low back pain – A meta‐analysis of population based surveys
Authors: Ferreira Manuela L. , Machado Gustavo , Latimer Jane , Maher Christopher , Ferreira Paulo H. , Smeets Rob J.
Published: December 2009

Little is known about factors determining health care‐seeking behavior in low back pain. While a number of studies have described general characteristics of health care utilization, only a few have aimed at appropriately assessing determinants of care‐seeking in back pain, by comparing seekers and non‐seekers. The objective of this systematic review was to identify determinants of health care‐seeking in studies with well‐defined groups of care‐seekers and non‐seekers with non‐specific low back pain.

A search was conducted in Medline, AMED, Cinahl, Web of Science, PsycINFO, National Research Register, Cochrane Library and LILACS looking for population‐ based surveys of non‐specific low back pain patients older than 18 years, published since 1966. To be included in the review, studies needed to report on characteristics of well‐defined groups of care‐seekers and non‐seekers. Methodological quality was assessed using a criteria list based on sampling, response rate, data reproducibility, power calculation and external validity. Risk estimates were expressed as odd ratios (95% confidence intervals). When possible, meta‐analyses were performed, using a random effects model.

Eleven studies were included in the review. Pooled results show that women are slightly more likely to seek care for their back pain as are patients with a previous history of back pain. Pain intensity was only slightly associated with care‐seeking, whereas patients with high levels of disability were nearly eight times more likely to seek care than patients with lower levels of disability.
The PsbS protein controls the macro‐organisation of photosystem II complexes in the grana membranes of higher plant chloroplasts
Authors: Kereïche Sami , Kiss Anett Z. , Kouřil Roman , Boekema Egbert J. , Horton Peter
Published: December 2009

The PsbS protein is a critical component in the regulation of non‐photochemical quenching (NPQ) in higher plant photosynthesis. Electron microscopy and image analysis of grana membrane fragments from wild type and mutant Arabidopsis plants showed that the semi‐crystalline domains of photosystem II supercomplexes were identical in the presence and absence of PsbS. However, the frequency of the domains containing crystalline arrays was increased in the absence of PsbS. Conversely, there was a complete absence of such arrays in the membranes of plants containing elevated amounts of this protein. It is proposed that PsbS controls the macro‐organisation of the grana membrane, providing an explanation of its role in NPQ.
Very long chain sphingolipids: Tissue expression, function and synthesis
Authors: Sandhoff Roger
Published: December 2009

Forecort membranes of all mammalian cells contain, in addition to phosphoglycerolipids and cholesterol, substantial amounts of sphingolipids. In most cells the acyl moieties of these sphingolipids are of long chain type (C16–24) and often saturated. However, epidermal keratinocytes and male germ cells largely express sphingolipids with very long chain‐acyl moieties (C26–C36) during their differentiation and maturation. This expression seems to depend on CerS3, one of six ceramide synthases. However, the complex biosynthetic sequence for both epidermal and testicular sphingolipids has not been elucidated completely. Whereas it is established that omega‐hydroxylated very long chain‐sphingolipids are essential for proper skin barrier function, the role of polyunsaturated very long chain‐sphingolipids (ceramides, sphingomyelins and glycosphingolipids) in differentiating spermatocytes/spermatids is just beginning to be revealed.
Autophagy and tumorigenesis
Authors: Chen Nan , Debnath Jayanta
Published: December 2009

Autophagy, or cellular self‐digestion, is activated in cancer cells in response to multiple stresses and has been demonstrated to promote tumor cell survival and drug resistance. Nonetheless, genetic evidence supports that autophagy functions as a tumor suppressor mechanism. Hence, the precise role of autophagy during cancer progression and treatment is both tissue and context dependent. Here, we discuss our current understanding of the biological functions of autophagy during cancer development, overview how autophagy is regulated by cancer‐associated signaling pathways, and review how autophagy inhibition is being exploited to improve clinical outcomes.
Costs of post‐abortion care in low‐ and middle‐income countries
Authors: Shearer Jessica C. , Walker Damian G. , Vlassoff Michael
Published: December 2009

Objective

To evaluate the quality of costing studies of post‐abortion care from low‐ and middle‐income countries and to describe costs in various settings.

Methods

A systematic review identified unit costs. Descriptive statistical analysis and univariate regression analysis identified drivers of unit costs of post‐abortion care.

Results

There are few cost studies from Asia or Eastern Europe. Data indicate that the cost (in 2007 international dollars) of post‐abortion care in Africa and Latin America is $392 and $430, respectively, per case.

Conclusion

Differences in post‐abortion care costs were associated with region, procedure, facility level, case severity, and whether the study was operations research. Methods varied between studies, and efforts should be made in future research to improve consistency. Additional data are needed from Asia and Eastern Europe, as well as the costs of medical methods of uterine evacuation. These data justify improved access to contraception and safe, legal abortion.
Evaluation of the QIAsymphony SP Workstation for Magnetic Particle—Based Nucleic Acid Purification from Different Sample Types for Demanding Downstream Applications
Authors: Kruhøffer Mogens , Voss Thorsten , Beller Katharina , Scherer Mario , Cramer Janina , Deutschmann Thomas , Homberg Cordula , Schlumpberger Martin , Lenz Christian
Published: December 2009

We evaluated automated nucleic acid (NA) extraction from a variety of different biological specimens using the QIAsymphony SP instrument. QIAsymphony DNA kits were used for DNA purification from human blood and from diverse human and animal tissue specimens. RNA was isolated from human blood stabilized in PAXgene Blood RNA tubes with the QIAsymphony PAXgene Blood RNA kit, and from human colon and bladder carcinoma biopsies using the QIAsymphony RNA kit. Photometric measurement, gel electrophoresis, and LabChip analysis on an Agilent 2100 Bioanalyzer (Agilent, Palo Alto, California) showed that the purified NAs were highly pure and intact, and that excellent yields were obtained. The DNA purified from blood and tissues performed well in single nucleotide polymorphism (SNP) array analysis, shown by call rates for the Affymetrix Genome-Wide Human 6.0 SNP arrays of > 99%. No significant differences were observed when array results of DNA purified either with magnetic particle technology or silica membrane technology were compared. The quality of the DNA allowed accurate allelic discrimination by TaqMan SNP PCR. Gene expression analyses of purified RNA either by “Human Endogenous Control Panel” TaqMan low-density array or on Affymetrix HG UI33 plus 2.0 GeneChips revealed high concordance between manually purified samples and those extracted on the QIAsymphony SP.
Wound Healing Assays in Well Plate—Coupled Microfluidic Devices with Controlled Parallel Flow
Authors: Conant Carolyn G. , Nevill J. Tanner , Schwartz Michael , Ionescu-Zanetti Cristian
Published: December 2009

The migratory or proliferative responses mounted by wounded cell monolayers are important to drug discovery and drug safety testing, as well as to basic research across a number of disciplines, including stem-cell biology, cell biology, ophthalmology, endocrinology, microbiology, oncology, and developmental biology. Scratch wounding by mechanical means is the golden standard to achieve an appropriate model system in which to study these cellular reactions. The scratch wounding technique is plagued by wound size irregularity, release of cytosolic contents along the wound edge, and difficulty in scaling up to higher throughput screening. To address these issues, we developed a microfluidic device coupled to a well plate in which wounds were produced enzymatically using highly controlled laminar flow streams. Within the device, epithelial cells were cultivated and exposed to different compounds. Proliferation and migration were characterized by bright-field microscopy. Resulting wound size was highly uniform compared with reported variability of manual scratch wounding. The protocol for wounding was fully automated using customized software, and response to wounding was followed in real time by microscopy.
An Automated 1536-Well Microplate Format Cytochrome P450 Inhibition Assay Using a Tecan Freedom EVO Workstation with Integrated Innovadyne Nanodrop II Dispenser
Authors: Litten Brett A. , Smith Robin , Banfield Eleanor
Published: December 2009

A Tecan EVO Workstation and Innovadyne Nanodrop II liquid dispenser have been integrated to provide an automated miniaturized cytochrome P450 inhibition assay, using 1536-well plate technology. The Tecan EVO was used to perform larger volume bulk reagent and compound dilution operations along with plate manipulations using the Tecan Robotic Manipulator. All reagent additions to the 1536-well microplates were performed exclusively by the Nanodrop dispenser, which is capable of accurate and precise pipetting at volumes as low as 100 nL. Miniaturization from 96- to 1536-well plate formats has enabled a fourfold increase in P450 inhibition assay capacity, while reducing reagent costs by approximately 20-fold.
Permethrin Spot-On Intoxication of Cats
Authors: Malik Richard , Ward Michael P , Seavers Aine , Fawcett Anne , Bell Erin , Govendir Merran , Page Stephen
Published: December 2009

Survey aims A questionnaire was sent to veterinarians in Australia to determine the approximate number of cats presenting for permethrin spot-on (PSO) intoxication over a 2-year period.

Findings Of the 269 questionnaires returned, 255 were eligible for analysis. A total of 207 respondents (81 %) reported cases of PSO intoxication in cats over the previous 2 years. In total, 750 individual cases were reported, with 166 deaths. While all deaths were generally attributable to intoxication, 39 cats were euthanased because owners were unable to pay the anticipated treatment costs. Brands of PSO implicated included Exelpet Flea (and Tick) Liquidator (Mars Australia) (146 respondents), Bayer Advantix (48), Purina Totalcare Flea Eliminator Line-On (19), Troy Ease-On (six) and Duogard Line-On (Virbac) (four); 67 respondents were not able to identify a specific product. Permethrin spot-on formulations were most commonly obtained from supermarkets (146 respondents), followed by pet stores (43), veterinary practices (16), and a range of other sources including produce stores and friends. The majority of intoxication cases reported involved PSOs labelled for use in dogs with specific label instructions such as ‘toxic to cats’. Owners applied these PSO products to their cats accidentally or intentionally. In some cases, exposure was through secondary contact, such as when a PSO product was applied to a dog with which a cat had direct or indirect contact.

Recommendations In the authors' view, because of the likelihood of inappropriate use and toxicity in the non-labelled species, over-the-counter products intended for use in either dogs or cats must have a high margin of safety in all species. Furthermore, PSOs should only be available at points of sale where veterinary advice can be provided and appropriate warnings given. As an interim measure, modified labelling with more explicit warnings may reduce morbidity and mortality.
Aetiology of Corneal Ulcers
Authors: Hartley Claudia
Published: December 2009

Overview Feline ulcerative keratitis is a common presenting complaint and is frequently a sequela of feline herpesvirus 1 (FHV-1) infection; so much so, in fact, that it is fair to assume an FHV-1 aetiology until proven otherwise. Other potential causes of ulceration are trauma or underlying eyelid abnormalities (entropion, ectropion, agenesis, dermoids, neoplasia), lash abnormalities (ectopic cilia, trichiasis), tear film abnormalities or neurological deficiencies (trigeminal nerve paralysis, facial nerve paralysis).

Clinical challenges The management of corneal ulceration in cats is frequently challenging, and treatment needs to be tailored carefully to the individual cat, its temperament, and the disease process present.

Evidence base The scientific literature on feline ulcerative keratitis is extensive, particularly that related to FHV-1 infection. The aim of this article is to review the aetiology and diagnosis of corneal ulceration in cats with particular reference to the evidence base available.

Patient group All age groups and breeds can suffer with ulcerative keratitis. Breed predispositions are present for some forms of corneal ulceration, and these are discussed.
AAFP-AAHA
Authors: Vogt Amy Hoyumpa , Rodan Ilona , Brown Marcus , Brown Scott , Buffington C A Tony , Forman M J LaRue , Neilson Jacqui , Sparkes Andrew
Published: December 2009

Background and goals Cats have become the most popular pet in the United States, yet statistics about veterinary care for cats remain troubling. 1 Although most owners consider their cats to be family members, cats are substantially underserved, compared with dogs. In 2006, owners took their dogs to veterinarians more than twice as often as cats, averaging 2.3 times/year, compared with 1.1 times/year for cats, and significantly more dogs (58%) than cats (28%) were seen by a veterinarian one or more times/year. 2 Cat owners often express a belief that cats ‘do not need medical care’. Two reasons for this misconception are that signs of illness are often difficult to detect, and cats are perceived to be self-sufficient. 2 One role of the veterinarian is to develop a partnership with cat owners that will pave the way for a lifelong health care plan. These guidelines aim to outline an evidence-based life stage wellness program to aid the veterinary medical team in delivering the best comprehensive care for cats. Specific goals are to provide:

Recommendations for optimal health care for cats throughout the different life stages. Practical suggestions and tools to facilitate improved veterinary visits and to enhance the client-veterinarian clinical encounter. A foundation from which to access sources of additional information.

Life stage classification Distinct life stages (age groups) in cats are not well defined, in part because individual animals and body systems age at different rates, a process that is influenced by many factors. These guidelines follow one convenient classification (see box below). These age designations help to focus attention on the physical and behavioral changes that occur at different stages (eg, congenital defects in kittens, obesity prevention in the junior cat). It must be recognized, however, that any age groupings are inevitably arbitrary demarcations along a spectrum, and not absolutes.

Evidence-based health care Supporting references for specific recommendations are supplied where possible, and any previously published guidelines on particular topics are referred to where relevant. Readers should note, however, that the guidelines panel was hampered in its efforts by the relative paucity of disease incidence data by age group that is available, and there is an urgent need for research to guide the future of evidence-based feline health care. 3
Inflammatory Pseudotumor of the Skull Base
Authors: Garg Vaani , Temin Nathaniel , Hildenbrand Peter , Silverman Mark , Catalano Peter J.
Published: December 2009

INTRODUCTION

Inflammatory pseudotumor is an idiopathic, non‐neoplastic mass lesion with few cases reported in the literature involving only the skull base and related structures. Imaging of skull‐base pseudotumors shows characteristics similar to that of nasopharyngeal carcinoma and lymphoma, thereby requiring a biopsy to exclude malignancy. Surgical versus medical management relates to the location of the mass, the extent of bony invasion, and the involvement of corresponding anatomic structures.

METHODS

A retrospective chart review of patients diagnosed with inflammatory pseudotumor of the skull base from a single tertiary care institution over a five‐year period.

RESULTS

Five cases of skull‐base pseudotumor have been identified and followed from one to four years. In our clinical experience, maintenance oral corticosteroids have proven effective in improving symptoms and significantly reducing radiologic tumor dimensions.

CONCLUSION

Inflammatory pseudotumor of the skull base is a challenging diagnosis due to its occult anatomic location, vague associated symptoms, and nonspecific histology. Low‐dose oral corticosteroids are often very effective in management.
Learning Curve for Piezosurgery in Well‐Trained Otological Surgeons
Authors: Salami Angelo , Mora Renzo , Mora Francesco , Guastini Luca , Salzano Francesco Antonio , Dellepiane Massimo
Published: December 2009

OBJECTIVE

Piezosurgery is an ultrasound instrument (24.7–29.5 kHz) capable of cutting bone without necrosis and nonmineralized tissue damage. The aim of this work has been to determine the time required for a well‐trained surgeon to perform otological surgery with the piezoelectric device.

STUDY DESIGN

Case series with planned data collection. Sixty‐three patients affected by otosclerosis and 63 by chronic otitis media were enrolled. For each disease, patients were divided into three numerically equal groups, with each group assigned to a well‐trained otological surgeon. Patients underwent stapedotomy (n = 63) and intact canal wall tympanoplasty (n = 63) with the piezoelectric device.

SETTING

ENT Department, University of Genoa (Italy).

SUBJECTS AND METHODS

We recorded “skin‐to‐skin” operation time, surgical success, surgical complication, and hospital stay duration. Before and one year after surgery, all patients underwent pure‐tone audiometry, tympanometry, recording of transient‐evoked otoacoustic emission, recording of distortion product otoacoustic emission, auditory brainstem response, and electronystamographic recording.

RESULTS

In each surgical technique, the piezoelectric device provided excellent control without side effects on the adjacent structures of the middle and inner ear.

CONCLUSION

The piezoelectric device is a new bony scalpel that uses microvibrations at ultrasonic frequency so that soft tissue (nerve, vessel, dura mater, etc) will not be damaged even on accidental contact with the cutting tip. A feature of the piezoelectric device is its good manageability, which makes it easy for a well‐trained otological surgeon to create a straight osteotomy line without any learning period: this renders the piezoelectric device suitable for bone surgery.
Plunging Ranula: Congenital or Acquired?
Authors: Morton Randall P. , Ahmad Zahoor , Jain Prabha
Published: December 2009

OBJECTIVE

To review our clinical experience with plunging ranula and examine the evidence in support of our impression that plunging ranula has a genetic basis.

STUDY DESIGN

Case series with chart review.

SETTING

Secondary otolaryngology service.

SUBJECTS AND METHODS

Review of the medical records of a clinical series of 80 consecutive plunging ranulas in 77 patients was conducted, with recording of clinical and radiological findings, surgical treatment, and outcome. A literature review using MEDLINE and OLD MEDLINE was performed.

RESULTS

The majority of plunging ranulas had no intraoral component on clinical examination, although evidence of mucus extravasation from the sublingual gland could be found both radiologically and histologically in all cases. There were four patients with bilateral plunging ranula and one instance of siblings with unilateral plunging ranula. Maoris and Polynesians comprised more than 82 percent of our cases; this was a significant overrepresentation of these ethnic groups (P < 0.0001). A very strong predominance of cases of Chinese origin was also evident in the literature.

CONCLUSION

The clinical findings and the supporting data from the literature, when viewed in light of information relating to the known anatomical anomaly of a dehiscence in the mylohyoid muscle and ectopic sublingual gland lying below the plane of the mylohyoid, appear to support the case for a genetic basis for this unusual clinical entity.