bluuebunny/crossref_metadata_2025 huggingface dataset:
Commonly Used Aggregate Materials and Placement Methods
Authors: Bloser Steven M.
Published: June 2007

Aggregate-surfaced roads are a viable component of the transportation network; they provide significant increases in road stability over earthen-surfaced roads while avoiding the high placement and maintenance costs of pavements. The use of higher-quality, more stable aggregates will significantly reduce both the cost of maintaining gravel roads and the environmental concerns related to road runoff. This paper aims to provide a better understanding of wearing course aggregates by describing a comparative analysis experiment done as part of Pennsylvania's Dirt and Gravel Road Maintenance Program. Three aggregates commonly used in Pennsylvania were placed side by side under two different placement methods for each type of aggregate as part of a 3-year study to compare their long-term durability and cost-effectiveness. The two methods tested were the “dump and spread” method known as tailgating and the application of aggregate by a motor paver. Cross-sectional surveys were done on each aggregate section for 3 years following placement to determine elevation changes in the road surfaces. No significant difference in performance was found between aggregate sections placed with a paver and the same aggregate placed by tailgating. Driving surface aggregate was the only aggregate of the three tested that did not show a statistically significant change in road elevation during the 3-year course of study. Results illustrate the importance of selecting a properly graded aggregate containing minimal clay and soil material for use as surface aggregate on low-volume roads.
Selection and Use of Locally Available Pavement Materials for Low-Volume Roads in Western Australia
Authors: Emery Stephen , Cocks Geoff , Keeley Ross
Published: June 2007

In many countries locally available granular materials are an important source for the base course and subbase in the construction of flexible pavements. On low-volume roads, these include fine-grained materials such as well-graded silty and clayey sands (sand–clay), coarse and medium-grained materials such as natural gravels, and materials produced by ripping and rolling rock. Many materials have been used that do not meet conventional selection criteria but still give satisfactory performance. Their choice is based on locally developed selection criteria, non-standard testing, and attention to construction technique. Selection criteria are presented here for lateritic base course gravels (covering a wide range of climates), crushed lateritic caprock, limestone, and sand–clay. The criteria have been adapted from research in several countries and refined through experience and field research in Western Australia. Some techniques are suggested for low-volume roads to cope with large truck combinations on the basis of the experience of Western Australia, where some road trains have more than 20 axles. Nonstandard test methods include the Western Australia confined compression test accelerated triaxial test and chemical composition tests. Suggestions are made concerning the bitumen surfacing of some materials to improve seal adhesion. Adequate strength by itself is insufficient for the successful use of locally available materials, and attention to construction technique and workability is needed. Guidelines are given on issues such as winning (mining), curing, mixing, oversize and compaction, dry-back, and surface preparation before sealing.
Evaluation Methodologies for Unpaved Road Surface Condition in Municipal District of Aquiraz, Ceará, Brazil
Authors: De Oliveira Almeida Ricardo Venescau , Nobre Ernesto Ferreira , De Castro Silva José Lassance
Published: June 2007

Changes are described that were made in the evaluation method for unpaved surfaces developed by the U.S. Army Corps of Engineers (USACE) so that the method could be applied to the municipal district of Aquiraz, in Ceará, northeast Brazil. The main objective of these changes is to take advantage of the experience of USACE, reflected in the curves used to determine the deduct values from the defects, and to make adjustments according to a series of surveys involving endogenous variables (materials, topography, etc.) and exogenous variables (climate, traffic, etc.) for the unpaved road. The curves are nomograms representing the severity levels of each type of defect considered by the method, except for the dust excess defect. Seven curves are used to define an index of the road surface condition, called the unsurfaced road condition index, which is a function of the total deduct value. The ALYNOMO method, which was based on data obtained during studies of three unpaved roads located in the municipal district of Aquiraz, was compared with the USACE method to verify the changes made. A modification in the application principle of the USACE method was made so that it can provide evaluations identical (or very close) to those obtained by the ALYNOMO method. The new method is called VENO.
Pavement Performance Evaluation of Three Canadian Low-Volume Test Roads
Authors: Tighe Susan , Falls Lynne Cowe , Doré Guy
Published: June 2007

New and improved pavement technologies are developed through laboratory investigations, construction and maintenance, theoretical analyses, long-term performance studies such as the Strategic Highway Research Program (SHRP) and the Canadian SHRP, and integrated programs of laboratory and field research. The latter, integrated approach is the subject of this study. Although various test roads have been placed in Canada over the past several decades, this study focuses on three test roads that examine low-volume road performance. These test roads are located in Ontario, Quebec, and Alberta and are being monitored by three Canadian universities. The background, test road objectives and location, design of the test roads and instrumentation, construction, and vehicle testing are first summarized briefly. Then, some ongoing projects at the three test roads and how results from the three test roads can be used either individually or collectively to improve current practices within Canada are discussed, with a focus on low-volume road technologies. Particular emphasis is placed on the performance of low-volume resource roads with respect to both traffic loading and environmental conditions. Findings from these studies will also be useful in the Canadian national calibration of the new Mechanistic–Empirical Pavement Design Guide.
Determining When to Place and Remove Spring Load Restrictions on Low-Volume Roads
Authors: Kestler Maureen A. , Berg Richard L. , Steinert Bryan C. , Hanek Gordon L. , Truebe Mark A. , Humphrey Dana N.
Published: June 2007

Damage to low-volume roads in seasonal frost areas can be kept to a minimum by implementing seasonal load restrictions (SLRs). However, not all agencies responsible for road management implement such restrictions, and among those that do, there is no standard technique. Some use qualitative methods, such as observation or dates. Others use quantitative methods, such as measuring or estimating stiffness or subsurface temperature. Loss and recovery of summertime pavement strengths can be directly measured with a falling-weight deflectometer (FWD). Alternatively, mathematical models of varying levels of complexity, using meteorological data, are in existence or are undergoing development for SLR placement. However, initial investment for an FWD can be prohibitive for agencies such as the U.S. Department of Agriculture Forest Service (FS), for which road management is not a primary mission. Similarly, such agencies have limited personnel to conduct detailed calculations required of complex mathematical models. Consequently, easy-to-use, low-cost alternatives are needed. In cooperation with other partnering agencies, FS has recently been evaluating several techniques for determining when to place and remove SLRs. Three methods that appear promising include (a) subsurface instrumentation for temperature and moisture, (b) portable or lightweight FWDs, and (c) the thaw index. Technology-and-development efforts in each of these areas are outlined here; field test programs, observations, and analysis procedures are discussed; and recommendations for implementing each method are provided.
Modeling the Response of Paved Low-Volume Roads under Various Traffic and Seasonal Conditions
Authors: Suleiman Nabil , Varma Amiy
Published: June 2007

Since low-volume road (LVR) systems were first designed and built, events such as deregulation and free-trade agreements and changes in economic growth patterns and in manufacturing and farming practices have resulted in increased truck movements and have accelerated the deterioration of paved LVRs, such as the ones in North Dakota, which were not designed for such heavy-truck traffic. The traditional empirical methods—use of the soil factor and R-value designs and the use of visual inspection and ride quality—to assess pavement performance are not adequate. A mechanistic model that uses material data and is capable of predicting pavement response under different traffic loading and seasonal conditions is deemed necessary. An analytical approach to determine and compare pavement response for different truck axle loadings under normal, thaw, and hot summer seasonal conditions on paved LVRs is discussed. A three-dimensional finite element program is used to model the pavement response in the form of total permanent deformation (TPD) and to calculate axle and truck damage factors. Various axle loadings representing U.S. axle weight limits on steering axles with single tires, single axles with dual tires, tandem axles, and tridem axles are used in this study. Seasonal variations are modeled through material strength parameters. The analysis of the TPD responses provides greater insight and understanding of how paved LVRs react to different axle configurations, levels of loading, and seasonal variations. This analysis ultimately may help to improve paved LVR design and planning practices and enhance seasonal load limit criteria.
Guidelines for Selecting Surfacing Alternatives for Unsealed Roads
Authors: Henning T. F. P. , Bennett C. R. , Kadar P.
Published: June 2007

Road networks are the vital arteries of societies. The need for roads to provide safe and comfortable access and thus contribute to economic sus-tainability and environmental protection has been increasing with time. Over the years, engineers have become knowledgeable in the optimization of resources for maintaining unsealed roads. Numerous manuals and guidelines have been produced, mostly for developed countries with extensive unsealed networks. Some manuals adopt innovative construction and maintenance methods for the surface layer of unsealed roads. The World Bank has commissioned the development of guidelines for surfacing alternatives for unsealed rural roads to assist countries in making surface selections. The guidelines offer detailed discussion of the following topics: summary of current international experience based on a survey of the literature, case studies and examples, and development of a decision framework for selecting the most appropriate surfacing for given circumstances. The decision framework was developed to offer guidelines and at the same time to remain flexible enough to be applicable for most circumstances. The framework offers a methodology consisting of a three-stage process: Stage 1—evaluation of the need for upgrading on the basis of local environmental and geographic conditions (this stage also allows for overriding political or other aspects); Stage 2—selection of suitable surface types and technologies from the presented list, to result in a short list of options; and Stage 3—suggestion of economic and financial analysis techniques to rank the technically feasible options developed during Stage 2. The guidelines and issues taken into account during the Stage 2 process of deciding on surface technologies are summarized.
Variability and Control of Gravel Road Visual Assessments
Authors: Van Der Gryp André , Van Zyl Gerrie
Published: June 2007

Annual visual assessments form the backbone of the Gravel Road Management System operated by the Provincial Government of the Western Cape in South Africa. Information is used to identify, quantify, and prioritize periodic maintenance activities; to describe the condition of individual roads and road networks; and to monitor their performance. The current assessment methodology is well described and has been applied for over 10 years. Although assessors are well trained and calibrated through regular formalized training sessions, inconsistencies still occur, which result in some variability of the final results. Efforts have been made to identify shortcomings in the assessment methodology, training, and quality control process. Duplicate assessments carried out each year on 10% of the road network were analyzed for this purpose, as were assessments of selected road sections carried out by all assessors during the annual training sessions. The assessment methodology and quality control process are discussed briefly, and the results of the study to improve the quality of visual assessments for network-level road management are highlighted.
Managing Low-Volume Roads with Wisconsin Information System for Local Roads
Authors: Ebeling Mary R. , Bittner Jason
Published: June 2007

Managers of low-volume roads face numerous challenges, including budgeting, maintenance decision making, and developing best practices. States such as Wisconsin have recently taken a proactive approach in assisting local officials in their roadway asset management activities. Aspects of the Wisconsin Information System for Local Roads (WISLR) that benefit local road managers by enhancing their asset management capabilities are discussed. Also offered are suggestions for future work to enhance roadway management tools for low-volume roads. WISLR originated with a Wisconsin Department of Transportation (WisDOT) effort to create a web-based geographic information system (GIS) that would provide both the state agency and the 1,922 local units of government with accurate tracking of roadway mileage and pavement conditions for the more than 100,000 mi of roads and streets under local government control. The sizes of local road systems vary widely by municipality, from less than 9 mi to more than 600 mi of roadway. Many of these roads fall into the low-volume category, particularly in the smaller jurisdictions. WisDOT hoped to provide municipalities with a powerful tool to track roadway mileage and conditions, as well as to aid in system management decisions. WISLR offers a unique opportunity for local governments to capitalize on the powerful tools made available by this application. WISLR combines GIS technology with database application tools based on the Pavement Surface Evaluation Rating system, allowing municipalities to perform long-range planning.
Network-Level Performance Measures for Low-Volume Highways in Alberta, Canada
Authors: Jurgens Roy , Chan Jack , Falls Lynne Cowe
Published: June 2007

The province of Alberta is responsible for 30,740 km of highway, of which 4,320 km is gravel surfaced. Approximately 8,750 km (28.5%) carries traffic volumes of fewer than 400 vehicles per day. The objectives of this study are to outline network-level performance measures for highways in Alberta and to ensure that they are effective for managing low-volume highways. The performance measures used relate primarily to physical condition and functional adequacy. In 2002 these measures were studied as part of a joint project with the University of Calgary in an attempt to make them more budget sensitive. Criteria were determined and subsequently adopted by Alberta Infrastructure and Transportation. Subsequent to that, a study was undertaken to determine optimal levels for these measures. These optimal measures would be used to set desired future performance targets. The results showed that on the order of 5% of the highways should remain in poor condition and should not be part of the backlog to be corrected. It was at first thought that the majority of these highways would be low-volume roads, but this did not prove to be true, primarily because of the younger age of these roads. The study also examines the cost-effectiveness of projects to pave low-volume gravel roads in comparison with other projects in the program. Cost-effectiveness is defined as agency cost per user per kilometer over a 20-year life-cycle. In conclusion, a future direction is suggested for the department to follow with respect to its low-volume highway improvements.
Roadex II Project
Authors: Munro Ron , Evans Richard , Saarenketo Timo
Published: June 2007

The ROADEX Project is a living case study on the benefits of partnering across road districts to make the best use of available budgets. The ROADEX Project partners had an early shared vision of cooperation that has since materialized in great benefits to their respective areas through collaboration in research and development and enhancement of their in-house capabilities by direct access to experience within the other partners' organizations. This sharing of information and experience has enabled them to have cost-effective research programs on shorter time scales than would otherwise have been the case and has avoided “reinventing the wheel” in research and development in each national district. The ROADEX II Project addresses the specific problems that arise in dealing with low-volume road management across the northern periphery of Europe so that reliable and regular year-round road networks can be provided to remote communities there. The outputs delivered in the ROADEX II Project offer a range of sustainable fit-for-purpose solutions to local road problems that together compose a tool kit of solutions for local managers to enable them to give better public service to their areas year after year.
Alternative Strategies for Rehabilitation of Low-Volume Roads in Nevada
Authors: Maurer Gayle , Bemanian Sohila , Polish Patty
Published: June 2007

An overview of the attempt by the Nevada Department of Transportation (NDOT) to find alternative rehabilitation strategies to rehabilitate its low-volume road network effectively is provided. Because of Nevada's continuing growth, NDOT is faced with the challenge of how to balance its available funding between pavement preservation and capacity improvement projects. NDOT is responsible for 13,000 lane miles of roadway, of which 3,385 lane miles (26%) qualify as low-volume roads. The low-volume roads have a two-directional average daily traffic of 400 or less. Five roadway projects with a combined total of 111 centerline miles were rehabilitated with 29 combinations of structural and surface strategies. The rehabilitation strategies investigated included full-depth reclamation with lime, cement, asphalts, and foamed asphalt. Various cold-mix, cold-in-place recycling with millings and different rejuvenating agents, and surface treatment test sections were constructed. The constructability issues that were reported during construction are discussed. In addition, pavement condition is examined and laboratory testing is reviewed. Results suggest that NDOT can use alternative rehabilitation strategies in place of its conventional method of 2-in. plant-mix bituminous surface overlay and chip seal to rejuvenate its low-volume roadway network. A cost saving of approximately $100,000 per centerline mile is anticipated.
Flexible Slurry–Microsurfacing System for Overlay Preparation
Authors: Johnson Eddie N. , Wood Thomas J. , Olson Roger C.
Published: June 2007

Microsurfacing mixtures are made of high-quality aggregate and asphalt emulsion components. They are produced at the project site by a mobile microsurfacing machine that mixes and places the product. Normal micro-surface designs contain approximately 13.5% emulsion and include a performance grade (PG) 64-22 asphalt cement (AC). This study investigates the field performance of softer-AC flexible slurry surfacing mixtures used for preparation and surface courses. A PG 48-34 AC was chosen for flexible slurry–microsurfacing mixtures constructed on four test cells at the Minnesota Road Research Project low-volume road facility near Albertville, Minnesota, in September 2005. This AC was used to produce mixtures for both surface preparation and wear courses. The mixtures used a reduced emulsion percentage for rut filling and an increased emulsion percentage for normal leveling courses. A single surface course mixture with the increased emulsion level was placed over the entire project. Pre- and postconstruction evaluations of cracking, rutting, and smoothness were performed. These evaluations were repeated at 6 months, following one winter of service. At 6 months an overall 71% of transverse cracking had reflected through the microsurface. Reflected distress from longitudinal cracks and patched areas was negligible. The rutting condition at 7 months was found to be similar to that at postconstruction, in which an overall 20% decrease was attributed to microsurfacing. Smoothness was favorably affected by microsurfacing construction. International roughness index values were correlated to the amount of material placed in the surface preparation course.
Nucleobase‐Caged Phosphoramidites for Oligonucleotide Synthesis
Authors: Heckel Alexander
Published: June 2007

Caged compounds are biologically active agents bearing a photolabile group in a strategic position, which makes them temporarily inactive. These compounds can then be delivered to a biological sample without immediately generating an effect. When the sample is then irradiated, e.g., with a laser in a (confocal) microscope, the activity of the substance is released with exact spatiotemporal and dose control. This unit deals with the synthesis of protected nucleoside phosphoramidites bearing a caging group on the nucleobase, which prevents the nucleobases from forming normal Watson‐Crick base pairs. These amidites can be used to generate caged oligodeoxynucleotides with a transitory local perturbation that adds an element of spatiotemporal control to oligonucleotide‐based applications.
Analyzing Real‐Time Video Microscopy: The Dynamics and Geometry of Vesicles and Tubules in Endocytosis
Authors: Hamilton Nicholas , Kerr Markus C. , Burrage Kevin , Teasdale Rohan D.
Published: June 2007

With the advent of live cell imaging microscopy, new types of mathematical analyses and measurements are possible. Many of the real‐time movies of cellular processes are visually very compelling, but elementary analysis of changes over time of quantities such as surface area and volume often show that there is more to the data than meets the eye. This unit outlines a geometric modeling methodology and applies it to tubulation of vesicles during endocytosis. Using these principles, it has been possible to build better qualitative and quantitative understandings of the systems observed, as well as to make predictions about quantities such as ligand or solute concentration, vesicle pH, and membrane trafficked. The purpose is to outline a methodology for analyzing real‐time movies that has led to a greater appreciation of the changes that are occurring during the time frame of the real‐time video microscopy and how additional quantitative measurements allow for further hypotheses to be generated and tested.
Imaging Tumor Cell Movement In Vivo
Authors: Kedrin Dmitriy , Wyckoff Jeffrey , Sahai Erik , Condeelis John , Segall Jeffrey E.
Published: June 2007

This unit describes the methods that we have been developing for analyzing tumor cell motility in mouse and rat models of breast cancer metastasis. Rodents are commonly used to provide a mammalian system for studying human tumor cells as xenografts in immunocompromised mice, as well as for following the development of tumors from a specific tissue type in transgenic lines. The Basic Protocol describes the standard methods used for generation of mammary tumors and imaging them. Additional protocols for labeling macrophages, blood vessel imaging, and image analysis are also included.
Fluorescent Detection of Lipid Droplets and Associated Proteins
Authors: Listenberger Laura L. , Brown Deborah A.
Published: June 2007

Most eukaryotic cells can store excess lipid in cytosolic lipid droplets. This unit discusses techniques for the visualization of lipid droplets and associated proteins in cultured mammalian cells. Protocols for the detection of lipid droplets with nile red and BODIPY 493/503 are included. The differences in the spectral properties of these two lipophilic dyes and advantages of each are discussed. The best method for combining visualization of intracellular lipid droplets with indirect immunofluorescent detection of lipid droplet–associated proteins is described. Techniques for sample fixation and permeabilization must be chosen carefully to avoid alterations to lipid droplet morphology. Immunofluorescent detection of adipophilin, a broadly expressed, lipid droplet–associated protein, widely used as a marker for lipid droplet accumulation, is presented as an example. Finally, a simple protocol for enhancing lipid droplet accumulation through supplementation with excess fatty acid is included.
Installation and Use of the Computational Proteomics Analysis System (CPAS)
Authors: Myers Tamra , Law Wendy , Eng Jimmy K. , McIntosh Martin
Published: June 2007

The community of proteomic researchers has been generating openly available software infrastructure for systematic proteomic data analyses and data management for the past several years. The Computational Proteomics Analysis System (CPAS) integrates many of these efforts into a single Web‐based platform for mining liquid chromatography–tandem mass spectrometry (LC‐MS/MS) proteomic experiments. CPAS incorporates several tools currently used in proteomic analysis, including the X! Tandem search engine and the PeptideProphet and ProteinProphet data mining tools. These tools and others are integrated into a single application built on the open‐source LabKey platform, an extensible architecture for developing high‐throughput biological applications. The CPAS analysis pipeline acts on data in standardized file formats, so that researchers may use CPAS with other search engines, including Mascot or SEQUEST, that follow a standardized procedure for reporting search engine results. All components of the CPAS toolkit are freely available at http://cpas.fhcrc.org.
Introduction to Cheminformatics
Authors: Wishart David S.
Published: June 2007

Cheminformatics is a relatively new field of information technology that focuses on the collection, storage, analysis, and manipulation of chemical data. The chemical data of interest typically includes information on small molecule formulas, structures, properties, spectra, and activities (biological or industrial). Cheminformatics originally emerged as a vehicle to help the drug discovery and development process, however cheminformatics now plays an increasingly important role in many areas of biology, chemistry, and biochemistry. The intent of this unit is to give readers some introduction into the field of cheminformatics and to show how cheminformatics not only shares many similarities with the field of bioinformatics, but that it can also enhance much of what is currently done in bioinformatics.
In Silico Drug Exploration and Discovery Using DrugBank
Authors: Wishart David S.
Published: June 2007

DrugBank is a fully curated drug and drug target database that contains information on nearly 5000 drugs, including >1200 FDA‐approved small molecule and biotech drugs as well as >3200 experimental drugs. Additionally, more than 14,000 protein or drug target sequences are linked to these drug entries. DrugBank is primarily focused on providing both the query/search tools and the biophysical data needed to facilitate drug discovery and drug development. This unit provides readers with a detailed description of how to effectively use the DrugBank database and how to navigate through the DrugBank Web site. It also provides specific examples of how to find chemical homologs of potential drug leads and how to identify potential drug targets from newly sequenced pathogens. The intent of this unit is to give readers some introduction into the field of cheminformatics (the study of chemical information) and to show how cheminformatics can be seamlessly integrated into the field of bioinformatics.
Detection and Analysis of Quorum‐Quenching Enzymes Against Acyl Homoserine Lactone Quorum‐Sensing Signals
Authors: Zhang Hai‐Bao , Wang Lian‐Hui , Zhang Lian‐Hui
Published: June 2007

Many Gram‐negative bacterial pathogens employ N‐acyl homoserine lactones (AHLs) quorum‐sensing signals for regulation of various biological functions. Several types of AHL‐inactivating enzymes, also known as quorum‐quenching enzymes, have been unveiled in recent years. These enzymes seem to play important roles in microbial physiology and ecology and hold promising potential in biotechnology. This unit describes methods based on a simple diffusion plate assay for qualitative detection and quantitative measurement of AHL‐inactivating enzyme activity. The qualitative detection method is suitable for rapid and large‐scale screening and identification of quorum‐quenching enzymes. Furthermore, HPLC methods are provided for accurate determination of whether the quorum‐quenching enzyme is a lactonase or an acylase. The unit also presents concise background information on the quorum‐quenching enzymes identified from various sources, including bacterial and mammalian species.
Interaction of Enterohemorrhagic Escherichia coli (EHEC) with Mammalian Cells: Cell Adhesion, Type III Secretion, and Actin Pedestal Formation
Authors: Savage Pamela J. , Campellone Kenneth G. , Leong John M.
Published: June 2007

Infection by the food‐borne pathogen enterohemorragic Escherichia coli (EHEC) can lead to diarrhea, hemorrhagic colitis, and, in the most serious cases, renal failure. A critical step in colonization is the unusual interaction between EHEC and the intestinal epithelium. EHEC is able to adhere to mammalian cells, and then, by injecting bacterial proteins, or “effectors,” into the host cell via a type III secretion system, induces the formation of attaching and effacing (AE) lesions characterized by the accumulation of filamentous actin directly beneath bound bacteria. This unit describes methods to evaluate the ability of EHEC to adhere to cultured mammalian cells, to secrete type III effectors, and to promote the formation of actin “pedestals.” These methods can not only be used to evaluate the contribution of specific EHEC gene products to adherence, type III secretion, and mammalian cell signaling, but also facilitate the analysis of the eukaryotic pathways controlling fundamental cellular processes such as actin assembly.
Isolation and Analysis of Mycobacterium tuberculosis Mycolic Acids
Authors: Vilchèze Catherine , Jacobs William R.
Published: June 2007

Mycolic acids are an important constituent of the mycobacterial cell wall. Changes in the structure or composition of mycolic acids have been associated with modification of cell wall permeability and attenuation of pathogenic Mycobacterium tuberculosis strains. This unit describes the isolation of M. tuberculosis mycolic acids and their analysis by either thin‐layer chromatography or high‐performance liquid chromatography. Both techniques have been extensively used to study (1) mycolic acid biosynthesis, (2) the role of mycolic acids in mycobacterial virulence, (3) the effect of antituberculosis drugs targeting the cell wall, and (4) taxonomic purposes.
The impact of aggressive priming, rumination, and frustration on prison sentencing
Authors: Vasquez Eduardo Antonio , Bartsch Vanessa O. , Pedersen William C. , Miller Norman
Published: June 2007

We tested the hypothesis that ruminating about a previous aggressive prime interacts with a subsequent minor frustration to augment aggression. Sixty participants watched a video showing a murder during a bank robbery (the aggressive prime). Those in the rumination condition were asked to write about the video for 20 min. In the no rumination condition, participants were given 20 min to complete an irrelevant task. Participants were then either frustrated or not frustrated. Our results supported the main hypothesis. Relative to the control condition, neither rumination nor frustration alone impacted aggression. Rumination, in combination with a minor frustration, however, increased the recommended prison sentence towards the targets. We discuss the implications of our findings. Aggr. Behav. 33:477–485, 2007. © 2007 Wiley‐Liss, Inc.
Whelk‐like Helixes of Polypyrrole Synthesized by Electropolymerization
Authors: Chen G. , Wang Z. Y. , Xia D. G. , Zhang L. , Hui R. , Zhang J. J.
Published: June 2007

A whelk‐like helix of polypyrrole was synthesized by an electropolymerization process. Its structure and properties were characterized by scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and cyclic voltammetry. The high‐resolution SEM images clearly show the whorls around the polypyrrole whelk body; these whorls have ordered periodic nanostructures on their surface. XPS analysis indicates that the polypyrrole structure is highly doped with sodium dodecyl sulfate, the chosen dopant. A novel spiral growth mechanism is proposed. The whelk‐like polypyrrole layer shows high thermal stability, superhydrophilicity, and strong electrocatalytic activity towards the oxidation of ascorbic acid.
The role of the terminal functional group of self‐assembled monolayers on fiber matrix adhesion
Authors: Feresenbet E. , Raghavan D. , Holmes G. A.
Published: June 2007

Adhesion at the fiber‐matrix interface of a composite is often influenced by a combination of factors such as mechanical interlocking, physicochemical interactions, and chemical bonding in the fiber‐matrix interphase region. We demonstrate the use of an approach using self‐assembled monolayers (SAMs) for studying the impact of one of the factors, chemical bonding, on the overall adhesion of the glass‐fiber/matrix interface. Transformation of these monolayer surfaces using conventional chemistry with a focus on the creation of a terminal functional group that interacts with epoxy resin is reported. The modified surfaces were characterized by ellipsometry, X‐ray photoelectron spectroscopy, and contact angle techniques for chlorosilane coverage, and in situ conversion. The adhesion of diglycidyl ether of bisphenol‐A resin to modified SAMs on E‐glass fibers was measured by performing single‐fiber fragmentation test. The extent of adhesion between the fiber and matrix was found to be dependent on the type of functional group at the terminal end of the SAM in contact with the epoxy matrix. Methyl terminal group resulted in the least adhesion, while amine terminal groups resulted in the most adhesion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Bead‐to‐fiber transition in electrospun polystyrene
Authors: Eda Goki , Shivkumar Satya
Published: June 2007

The morphological transition, namely bead‐to‐fiber transition, of electrospun polymer was examined for polystyrene, with its molecular weight ranging from 19,300 to 1,877,000 g/mol. Tetrahydrofuran and N,N‐dimethylformamide were used as solvents to examine the effects of solvent properties on the morphological variations. Polymer molecular weight and solvent properties had a significant effect on the morphology of beads as well as fibers. Observation of fiber diameter and its distribution suggested that the effect of molecular weight and solvent may be independent. The critical concentrations at which incipient and complete fibers were observed were found to decrease significantly with molecular weight, as can be expected. The effect of solvents on these critical concentrations was minimal for moderate to high‐molecular‐weight (>100,000 g/mol) solutions. For low‐molecular‐weight solutions, the transition occurred at concentrations much lower than those predicted by a model, based exclusively on chain entanglements. Rapid solidification of jet which is expected to occur with concentrated solutions may play a vital role in establishing stable fibers during electrospinning. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Mechanical and physical characterization of polyoxymethylene processed by high‐velocity compaction
Authors: Jauffrès D. , Lame O. , Vigier G. , Doré F. , Chervin C.
Published: June 2007

Conventional polymer processes, such as injection and extrusion, require the melting of the polymer. High‐velocity compaction (HVC) allows the processing of polymer powders via sintering without the need of a melting stage. It opens up a new horizon for polymers that have processing issues linked to the melting stage. Because of chemical degradation above the melting point and significant shrinkage, the injection of semicrystalline polymer polyoxymethylene (POM) is often problematic. Nascent, highly crystalline POM powder has been successfully processed by HVC, and this process appears to be an interesting alternative to injection for certain applications. POM processed by HVC has a remarkably high stiffness but is brittle. A microstructural investigation, involving differential scanning calorimetry experiments and scanning electron microscopy, has been conducted to explain these unusual mechanical properties. It appears that in POM processed by HVC, the stiffness is due to particularly high crystallinity, and brittleness is intrinsic to nascent POM powder. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Improving polypropylene microcellular foaming through blending and the addition of nano‐calcium carbonate
Authors: Huang Han‐Xiong , Wang Jian‐Kang
Published: June 2007

This article reports an attempt to improve polypropylene (PP) microcellular foaming through the blending of PP with high‐density polyethylene (HDPE) as a minor component and the incorporation of nano‐calcium carbonate (nano‐CaCO3) into PP and its blends with HDPE. Three HDPEs were selected to form three blends with a viscosity ratio less than, close to, or greater than unity. Two concentrations of nano‐CaCO3, 5 and 20 wt %, were used. The blends and nanocomposites were prepared with a twin‐screw extruder. The foaming was carried out by a batch process with supercritical carbon dioxide as a blowing agent. The online shear viscosity during compounding and the dynamic rheological properties of some samples used for foaming were measured. The cell structure of the foams was examined with scanning electron microscopy (SEM), and the morphological parameters of some foams were calculated from SEM micrographs. The rheological properties of samples were used to explain the resulting cell structure. The results showed that the blend with a viscosity ratio close to unity produced a microcellular foam with the minimum mean cell diameter (0.7 μm) and maximum cell density (1.17 × 1011 cells/cm3) among the three blends. A foamed PP/nano‐CaCO3 composite with 5 wt % nano‐CaCO3 exhibited the largest cell density (8.4 × 1011 cells/cm3). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Low‐temperature, sol–gel‐synthesized, silver‐doped titanium oxide coatings to improve ultraviolet‐blocking properties for cotton fabrics
Authors: Onar Nurhan , Ebeoglugil M. Faruk , Kayatekin Isıl , Celik Erdal
Published: June 2007

A new finishing process for cotton fabrics was developed that includes the treatment of cotton fabrics by a pad–dry–cure method with different amounts of Ag‐doped, Ti‐based transparent solutions prepared with a sol–gel method. Within this framework, transparent solutions were prepared with solutions of Ag‐ and Ti‐based precursors, isopropyl alcohol, and glacial acetic acid. Then, cotton fabrics were padded with these solutions. After these processes, the padded fabrics were dried at 80°C for 30 min in air, and the coated fabrics were cured at 150°C for 5 min to produce Ag‐doped TiO2 films on the fabrics. The turbidity, pH, wettability, and rheological properties of the prepared solutions were measured. The thermal, structural, and microstructural properties of the coatings were extensively characterized with differential thermal analysis/thermogravimetry, Fourier transform infrared, X‐ray diffraction, and scanning electron microscopy/energy‐dispersive spectroscopy. The thicknesses of the films were estimated with a refractometer and a spectrophotometer. In addition, the add‐on values, wash fastness, ultraviolet protection, lightness, and contact angles of the coated fabrics were determined. The treatment of the fabrics with a 30 atom % Ag doped, Ti‐based solution imparted to the fabrics a good ultraviolet‐protection factor rating of 15+, which was an increase of 10+ in comparison with the ultraviolet‐protection factor of the untreated fabric (5+). The produced fabrics were also water‐resistant. Hence, this method produced multifunctional fabrics that were water‐resistant and ultraviolet‐protective. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Curing of bromobutyl elastomer composition using a xanthogen polysulphide accelerator for medical drug delivery device applications
Authors: Ohbi D. S. , Purewal T. S. , Shah T. , Siores E.
Published: June 2007

Bromobutyl elastomer (BIIR) can be used for sealing medical drug delivery devices due to its high resistance to permeability by moisture and gases which are known to deteriorate the performance of pharmaceutical drugs. However, its use is restricted since the traditional accelerators used for crosslinking BIIR leave reaction residues which can leach out and contaminate drugs. An accelerator based on xanthogen polysulphide (DIXP) does not leave reaction residues as it is totally consumed during crosslinking. From these considerations DIXP was used to formulate a BIIR composition for seals in medical devices. The isothermal kinetic reaction curve for BIIR showed that the crosslinking region consists of two parts. The first part had a reaction order (n) = 1 and the second stage had a lower n = 0.6–0.7. The rate constants and the activation energies for the two stages were determined. Increasing the time and temperature variables of crosslinking increased the dynamic elastic shear modulus (G′) in BIIR according to the kinetic theory of vulcanization, however the moisture ingress showed an initial decrease followed by an inflection where increasing the variables caused increased moisture ingress. This increase is believed to be caused by the volatile gaseous byproducts produced in the crosslinking reaction of DIXP which change the microstructure of BIIR. The crosslinking conditions for minimizing moisture ingress in BIIR and achieving a high G′ were identified. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Shape memory polymers based on uniform aliphatic urethane networks
Authors: Wilson T. S. , Bearinger J. P. , Herberg J. L. , Marion J. E. , Wright W. J. , Evans C. L. , Maitland D. J.
Published: June 2007

Aliphatic urethane polymers have been synthesized and characterized, using monomers with high molecular symmetry, to form amorphous networks with very uniform supermolecular structures, which can be used as photo‐thermally actuable shape memory polymers (SMPs). The monomers used include hexamethylene diisocyanate (HDI), trimethylhexamethylenediamine (TMHDI), N,N,N′,N′‐tetrakis(hydroxypropyl)ethylenediamine (HPED), triethanolamine (TEA), and 1,3‐butanediol (BD). The new polymers were characterized by solvent extraction, NMR, XPS, UV/VIS, DSC, DMTA, and tensile testing. The resulting polymers were found to be single phase amorphous networks with very high gel fraction, excellent optical clarity, and extremely sharp single glass transitions in the range of 34–153°C. Thermomechanical testing of these materials confirms their excellent shape memory behavior, high recovery force, and low mechanical hysteresis (especially on multiple cycles), effectively behaving as ideal elastomers above Tg. We believe these materials represent a new and potentially important class of SMPs, and should be especially useful in applications such as biomedical microdevices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Aqueous reactive PU prepolymer containing sulfoisophthalate sodium for hydrophilic finishing and antistatic finishing of poly(ethylene terephthalate) fabrics
Authors: Yen Meng‐Shung , Huang Ching‐Nan
Published: June 2007

In the study, we allowed PEG and dimethyl 5‐sulfoisophthalate sodium salt (SIP) to undergo transesterification to obtain PEG containing sulfonic groups (SE), then used SE and isophorone diisocyanate as soft and hard chains, respectively, and methyl ethyl ketoxime, hydroxyethyl methacrylate or 2,3‐Epoxy‐1‐propanol as blocking reagents to synthesize three kinds of reactive urethane oligomers (MSE, HSE, and OSE). PET textiles treated by oligomers were investigated for their effects to the durable hydrophilic properties of PET fibers under different processing temperatures, time lengths, and oligomer concentrations. The results are concluded and described later: The add‐on and durability of processed fabrics both were improved following the rise of processing temperature and a longer processing time. When oligomer concentration was increased, the add‐on on processed textiles also increased, but their durability decreased. When PEG segment was larger, the add‐on and durability both decreased. The hydrophilicity of processed textiles was proportional to the increase of oligomer concentration. The processing time was more crucial to the hydrophilic property of HSE processed textiles, but for that of MSE, the processing temperature was more important. The hydrophilic property of OSE processed textiles absolutely depended on the add‐on of processed textiles. Textiles processed in oligomers of PEG molecular weight 1000 showed the highest vertical wicking height. Within these three kinds of oligomers, MSE led to the highest add‐on on processed textiles and HSE textiles possessed the best of durability. OSE processed textiles possessed the best hydrophilic efficiency and electrostatic dissipating property. Textiles processed in HSE containing PEG molecular weight 1000 could have the best hydrophilic and durability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Carvacrol losses from soy protein coated papers as a function of drying conditions
Authors: Chalier Pascale , Arfa Afef Ben , Preziosi‐Belloy Laurence , Gontard Nathalie
Published: June 2007

The influence of drying conditions (temperature/time) on carvacrol losses was investigated for antimicrobial packaging obtained by coating paper with soy protein solutions containing 30% of carvacrol (w/w of SPI) as antimicrobial agent. The lowest carvacrol losses ranging from 25 to 30% were obtained for three drying conditions: high temperature and short time 250°C for 20 s or mild conditions 50°C for 210 s and 25°C for 3 h. In contrast, intermediate drying conditions (100°C/90 s and 150°C/45 s) led to carvacrol losses higher than 50%. The weaker losses observed for drying at 250°C compared with the intermediate temperatures could be explained by the rapid formation of a thick and protective crust that acted as a selective membrane letting to past water and retaining carvacrol. For drying at 150°C, high losses were related to water vaporization and carvacrol carrying as attested by the presence of holes observed by SEM and due to bubble formation and bursting. If drying conditions affected the carvacrol losses and its retention from coated papers during storage at 30°C and 60% relative humidity, the antimicrobial activity was found only dependent on carvacrol amount of the coated papers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007