bluuebunny/crossref_metadata_2025 huggingface dataset:
Oral Oxymorphone for Pain Management
Authors: Chamberlin Kevin W , Cottle Mark , Neville Rebecca , Tan Jennifer
Published: June 2007

Objective

To describe the pharmacology, safety and efficacy, and rationale for use of oral oxymorphone for the management of acute and chronic moderate-to-severe pain.

Data Sources

A PubMed/MEDLINE search (1966-March 2007) was conducted using the following terms: oral oxymorphone, oxymorphone, EN 3202, EN 3203, Opana, and Opana ER. Manufacturer-provided data (package inserts) and abstracts presented at the American Pain Society meetings (2003–2006) were also reviewed.

Study Selection and Data Extraction

Human studies evaluating the safety and efficacy of oral oxymorphone in pain management were considered; animal and non–English-language data were excluded.

Data Synthesis

Oral oxymorphone is a semisynthetic opioid agonist that is specific for the μ-opioid receptor and approved to treat both acute and chronic pain. Unlike other opioids, such as oxycodone, oxymorphone does not bind to the κ-opioid receptor. Due to extensive liver metabolism, oral oxymorphone is contraindicated in patients with moderate-to-severe hepatic impairment; however, no clinically significant CYP3A4, 2C9, or 2D6 mediated drug-drug interactions have been noted. Elderly patients may experience a 40% increase in plasma concentrations, while renally impaired patients may have a 57–65% increase in bioavailability. Food can increase the rate of absorption by as much as 50%, necessitating dosing either 1 hour before or 2 hours after a meal. Oxymorphone's primary adverse effects are similar to those of other opioids: nausea, vomiting, pruritus, pyrexia, and constipation.

Conclusions

Oxymorphone is an oral therapeutic option approved for the treatment of acute and chronic moderate-to-severe pain. Oxymorphone has a safety and efficacy profile similar to that of other commonly used pure opioids (morphine, oxycodone, hydromorphone). Like oxycodone and morphine, oxymorphone also has immediate-release and extended-re lease formulations. Since cost alone is not yet favorable for oxymorphone over oxycodone or morphine, further studies of comparative efficacy targeting potential advantages of oxymorphone over other opioids are necessary before considering it for addition to a formulary.
Expression of the Epithelial Marker E-Cadherin by Thyroid C Cells and Their Precursors During Murine Development
Authors: Kameda Yoko , Nishimaki Toshiyuki , Chisaka Osamu , Iseki Sachiko , Sucov Henry M.
Published: June 2007

Studies of chick–quail chimeras have reported that avian ultimobranchial C cells originate from the neural crest. It has consequently been assumed, without much supporting evidence, that mammalian thyroid C cells also originate from the neural crest. To test this notion, we employed both Connexin43-lacZ and Wnt1-Cre/R26R transgenic mice, because their neural crest cells can be marked. We also examined the immunohistochemical expression of a number of markers that identify migratory or postmigratory neural crest cells, namely, TuJ1, neurofilament 160, nestin, P75NTR, and Sox10. Moreover, we examined the expression of E-cadherin, an epithelial cell marker. At embryonic day (E)10.5, the neural crest cells densely populated the pharyngeal arches but were not distributed in the pharyngeal pouches, including the fourth pouch. At E11.5, the ultimobranchial rudiment formed from the fourth pouch and was located close to the fourth arch artery. At E13.0, this organ came into contact with the thyroid lobe, and at E13.5, it fused with this lobe. However, the ultimobranchial body was not colonized by neural crest–derived cells at any of these developmental stages. Instead, all ultimobranchial cells, as well as the epithelium of the fourth pharyngeal pouch, were intensely immunoreactive for E-cadherin. Furthermore, confocal microscopy of newborn mouse thyroid glands revealed colocalization of calcitonin and E-cadherin in the C cells. The cells, however, were not marked in the Wnt-Cre/R26R mice. These results indicated that murine thyroid C cells are derived from the endodermal epithelial cells of the fourth pharyngeal pouch and do not originate from neural crest cells. (J Histochem Cytochem 55: 1075–1088, 2007)
Fasting and Glucose Effects on Pituitary Leptin Expression
Authors: Crane Christopher , Akhter Noor , Johnson Brandy W. , Iruthayanathan Mary , Syed Farhan , Kudo Akihiko , Zhou Yi-Hong , Childs Gwen V.
Published: June 2007

Leptin, a potent anorexigenic hormone, is found in the anterior pituitary (AP). The aim of this study was to determine whether and how pituitary leptin–bearing cells are regulated by nutritional status. Male rats showed 64% reductions in pituitary leptin mRNA 24 hr after fasting, accompanied by significant (30–50%) reductions in growth hormone (GH), prolactin, and luteinizing hormone (LH), and 70–80% reductions in target cells for gonadotropin-releasing hormone or growth hormone-releasing hormone. There was a 2-fold increase in corticotropes. Subsets (22%) of pituitary cells coexpressed leptin and GH, and <5% coexpressed leptin and LH, prolactin, thyroid-stimulating hormone, or adrenocortico-tropic hormone. Fasting resulted in significant (55–75%) losses in cells with leptin proteins or mRNA, and GH or LH. To determine whether restoration of serum glucose could rescue leptin, LH, and GH, additional fasted rats were given 10% glucose water for 24 hr. Restoring serum glucose in fasted rats resulted in pituitary cell populations with normal levels of leptin and GH and LH cells. Similarly, LH and GH cells were restored in vitro after populations from fasted rats were treated for as little as 1 hr in 10–100 pg/ml leptin. These correlative changes in pituitary leptin, LH, and GH, coupled with leptin's rapid restoration of GH and LH in vitro, suggest that pituitary leptin may signal nutritional changes. Collectively, the findings suggest that pituitary leptin expression could be coupled to glucose sensors like glucokinase to facilitate rapid responses by the neuroendocrine system to nutritional cues. (J Histochem Cytochem 55: 1059–1073, 2007)
Discrete-continuum analysis of shear banding in the direct shear test
Authors: Wang J. , Dove J. E. , Gutierrez M. S.
Published: June 2007

The direct shear test is a widely used method for determining peak and critical state strength parameters for soil and for soil-manufactured material interfaces. The objective of this research was to examine the direct shear test by way of a discrete-continuum approach. Specifically, the effects of non-coaxiality between the principal stress and the principal strain increment direction and the deviation of zero extension direction from horizontal are examined. A new, mesh-free method of evaluating internal strains is proposed, and a new flow rule is also presented. The results from discrete simulations indicate that development of shear bands proceeds from the side boundaries toward the centre with both primary and secondary bands formed. A distinct shear band along the middle plane develops around peak state in a dense sample. Simulation data using the new flow rule and laboratory test data using a conventional flow rule are in good agreement, indicating that the effect of non-coaxiality is small at peak state. Deviation of the zero linear extension direction at peak state is less than 3°. It is concluded that boundary measurements made on the direct shear apparatus are suitable for determining strength and volume change behaviour of granular soils.
Tissue-Specific Effects of Rosiglitazone and Exercise in the Treatment of Lipid-Induced Insulin Resistance
Authors: Lessard Sarah J. , Rivas Donato A. , Chen Zhi-Ping , Bonen Arend , Febbraio Mark A. , Reeder Donald W. , Kemp Bruce E. , Yaspelkis Ben B. , Hawley John A.
Published: June 2007

Both pharmacological intervention (i.e., thiazolidinediones [TZDs]) and lifestyle modification (i.e., exercise training) are clinically effective treatments for improving whole-body insulin sensitivity. However, the mechanism(s) by which these therapies reverse lipid-induced insulin resistance in skeletal muscle is unclear. We determined the effects of 4 weeks of rosiglitazone treatment and exercise training and their combined actions (rosiglitazone treatment and exercise training) on lipid and glucose metabolism in high-fat–fed rats. High-fat feeding resulted in decreased muscle insulin sensitivity, which was associated with increased rates of palmitate uptake and the accumulation of the fatty acid metabolites ceramide and diacylglycerol. Impairments in lipid metabolism were accompanied by defects in the Akt/AS160 signaling pathway. Exercise training, but not rosiglitazone treatment, reversed these impairments, resulting in improved insulin-stimulated glucose transport and increased rates of fatty acid oxidation in skeletal muscle. The improvements to glucose and lipid metabolism observed with exercise training were associated with increased AMP-activated protein kinase α1 activity; increased expression of Akt1, peroxisome proliferator–activated receptor γ coactivator 1, and GLUT4; and a decrease in AS160 expression. In contrast, rosiglitazone treatment exacerbated lipid accumulation and decreased insulin-stimulated glucose transport in skeletal muscle. However, rosiglitazone, but not exercise training, increased adipose tissue GLUT4 and acetyl CoA carboxylase expression. Both exercise training and rosiglitazone decreased liver triacylglycerol content. Although both interventions can improve whole-body insulin sensitivity, our results show that they produce divergent effects on protein expression and triglyceride storage in different tissues. Accordingly, exercise training and rosiglitazone may act as complementary therapies for the treatment of insulin resistance.
Hematopoietic Stem Cells Derived From Adult Donors Are Not a Source of Pancreatic β-Cells in Adult Nondiabetic Humans
Authors: Butler Alexandra E. , Huang Andrew , Rao P. Nagesh , Bhushan Anil , Hogan William J. , Rizza Robert A. , Butler Peter C.
Published: June 2007

OBJECTIVE—Type 1 and type 2 diabetes are characterized by an ∼98 and ∼65% loss of pancreatic β-cells, respectively. Efforts to reverse either form of diabetes increasingly focus on the possibility of promoting β-cell replacement and/or regeneration. Islet transplantation has been explored, but it does not provide long-term insulin independence. One possible source of β-cell regeneration is hematopoietic stem cells. In mice, there are conflicting data as to whether hematopoietic stem cells contribute to pancreatic β-cells. We sought to establish whether hematopoietic stem cells (derived from adult donors) transdifferentiate into pancreatic β-cells in adult humans.

RESEARCH DESIGN AND METHODS—We addressed this in 31 human pancreata obtained at autopsy from hematopoietic stem cell transplant recipients who had received their transplant from a donor of the opposite sex.

RESULTS—Whereas some donor-derived cells were observed in the nonendocrine pancreata, no pancreatic β-cells were identified that were derived from donor hematopoietic stem cells, including two cases with type 2 diabetes.

CONCLUSIONS—We conclude that hematopoietic stem cells derived from adult donors contribute minimally to pancreatic β-cells in nondiabetic adult humans. These data do not rule out the possibility that hematopoietic stem cells contribute to pancreatic β-cells in childhood or in individuals with type 1 diabetes.
Circulating Levels of Endothelial Adhesion Molecules and Risk of Diabetes in an Ethnically Diverse Cohort of Women
Authors: Song Yiqing , Manson JoAnn E. , Tinker Lesley , Rifai Nader , Cook Nancy R. , Hu Frank B. , Hotamisligil Gokhan S. , Ridker Paul M. , Rodriguez Beatriz L. , Margolis Karen L. , Oberman Albert , Liu Simin
Published: June 2007

Elevated circulating levels of soluble adhesion molecules as markers of endothelial dysfunction have been related to insulin resistance and its associated metabolic abnormalities. However, their associations with type 2 diabetes remain inconclusive. We conducted a prospective nested case-control study to examine the associations between plasma levels of E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) and diabetes risk among 82,069 initially healthy women aged 50–79 years from the Women's Health Initiative Observational Study. During a median follow-up of 5.9 years, 1,584 incident diabetes case subjects were matched with 2,198 control subjects by age, ethnicity, clinical center, time of blood draw, and follow-up time. Baseline median levels of the biomarkers were each significantly higher among case subjects than among control subjects (E-selectin, 49 vs. 37 ng/ml; ICAM-1, 324 vs. 280 ng/ml; and VCAM-1, 765 vs. 696 ng/ml [all P values <0.001]). After adjustment for risk factors, the relative risks of diabetes among women in the highest quartile versus those in the lowest quartile were 3.46 for E-selectin (95% CI 2.56–4.68; P for trend <0.0001), 2.34 for ICAM-1 (1.75–3.13; P for trend <0.0001), and 1.48 for VCAM-1 (1.07–2.04; P for trend = 0.009). E-selectin and ICAM-1 remain significant in each ethnic group. In conclusion, higher levels of E-selectin and ICAM-1 were consistently associated with increased diabetes risk in a multiethnic cohort of U.S. postmenopausal women, implicating an etiological role of endothelial dysfunction in the pathogenesis of type 2 diabetes.
Updated and Revised Diabetes Family Conflict Scale
Authors: Hood Korey K. , Butler Deborah A. , Anderson Barbara J. , Laffel Lori M.B.
Published: June 2007

OBJECTIVE— The purpose of this study was to update the Diabetes Family Conflict Scale (DFCS) in the era of intensive diabetes management and provide an indication of its psychometric properties.

RESEARCH DESIGN AND METHODS— The revised DFCS and measures of negative emotions around blood glucose monitoring (BGM), quality of life, and perceived parental burden from diabetes management were completed by 202 children and adolescents with type 1 diabetes and their primary caregivers. Insulin regimen, adherence, and glycemic control were also assessed.

RESULTS— The revised DFCS demonstrated strong psychometric properties. There was acceptable internal consistency for child and caregiver forms of the DFCS. Factor analysis revealed two factors related to direct and indirect management tasks. Both child (r = 0.27, P < 0.01) and caregiver (r = 0.26, P < 0.01) DFCS scores were correlated with A1C values. Multivariate analysis of factors usually associated with A1C values showed an additive, independent contribution of diabetes-specific family conflict to the prediction of glycemic control: F (12,189) = 6.17, P < 0.01, R2 = 0.28. Conflict around direct management tasks (e.g., BGM) was a more important predictor of higher A1C levels than conflict around indirect management tasks (e.g., telling friends about diabetes).

CONCLUSIONS— The revised and updated DFCS demonstrates strong psychometric properties and can be used as a tool for measuring the level of diabetes-specific conflict in families with children and adolescents with type 1 diabetes.
A Prospective Study of Overall Diet Quality and Risk of Type 2 Diabetes in Women
Authors: Fung Teresa T. , McCullough Marjorie , van Dam Rob M. , Hu Frank B.
Published: June 2007

OBJECTIVE— The aim of this article was to assess the association between the Alternate Healthy Eating Index (AHEI) and risk of type 2 diabetes in women.

RESEARCH DESIGN AND METHODS— A total of 80,029 women aged 38–63 years in the Nurses’ Health Study were followed from 1984 to 2002. The AHEI score was computed from dietary information collected from five repeated food frequency questionnaires administered between 1984 and 1998. Relative risks (RRs) for type 2 diabetes were calculated using Cox proportional hazards models and adjusted for known diabetes risk factors. We also examined how changes in score in 4, 6–8, and 10–12 years are associated with diabetes risk.

RESULTS— We ascertained 5,183 incident cases of type 2 diabetes during 18 years of follow-up. Women who scored high on the AHEI had a lower risk (RR comparing top to bottom score quintile 0.64 [95% CI 0.58–0.71], Ptrend < 0.0001) for diabetes. Women with consistently high AHEI scores throughout follow-up, compared with those with consistently low scores, had the lowest risk for diabetes. In addition, women whose AHEI scores improved during follow-up, even during recent years, had a lower risk of diabetes than did women whose (low) score did not change.

CONCLUSIONS— A higher AHEI score is associated with a lower risk of type 2 diabetes in women. Therefore, the AHEI score may be a useful clinical tool to assess diet quality and to recommend for the prevention of diabetes.
Fasting and Postprandial Glycoxidative and Lipoxidative Stress Are Increased in Women With Type 2 Diabetes
Authors: Schindhelm Roger K. , Alssema Marjan , Scheffer Peter G. , Diamant Michaela , Dekker Jacqueline M. , Barto Rob , Nijpels Giel , Kostense Piet J. , Heine Robert J. , Schalkwijk Casper G. , Teerlink Tom
Published: June 2007

OBJECTIVE— We studied acute changes in markers of glycoxidative and lipoxidative stress, including oxidized LDL, Nε-(carboxyethyl)-lysine (CEL), Nε-(carboxymethyl)-lysine (CML), and 3-deoxyglucosone (3DG), following two consecutive meals.

RESEARCH DESIGN AND METHODS— Postmenopausal women (27 with normal glucose metabolism [NGM], 26 with type 2 diabetes) received two consecutive fat-rich meals and two consecutive carbohydrate-rich meals on two occasions. Glucose and triglyceride concentrations were measured at baseline and 1, 2, 4, 6, and 8 h following breakfast; lunch was given at 4 h. Oxidized LDL–to–LDL cholesterol ratio, CEL, CML, and 3DG were measured at baseline and at 8 h.

RESULTS— Fasting oxidized LDL–to–LDL cholesterol ratio, 3DG, and CML were higher in women with type 2 diabetes compared with women with NGM and were comparable to the postprandial values at 8 h in NGM. Postprandial rises in the oxidized LDL–to–LDL cholesterol ratio and 3DG were similar in both groups. However, the oxidized LDL–to–LDL cholesterol ratio increased more after the fat-rich meals, whereas CML and 3DG increased more after the carbohydrate-rich meals. After the fat-rich meals, the increase in the oxidized LDL–to–LDL cholesterol ratio correlated with postprandial triglycerides, whereas the increase in 3DG was correlated with postprandial glucose.

CONCLUSIONS— The acute changes in markers of glycoxidative and lipoxidative stress in both type 2 diabetes and NGM suggest that postabsorptive oxidative stress may partly underlie the association of postprandial derangements and cardiovascular risk.
Degree of Obesity and Glucose Allostasis Are Major Effectors of Glucose Tolerance Dynamics in Obese Youth
Authors: Weiss Ram , Cali Anna M. , Dziura James , Burgert Tania S. , Tamborlane William V. , Caprio Sonia
Published: June 2007

OBJECTIVE— One of the signals for the β-cell to maintain an adequate response to worsening insulin sensitivity is elevated ambient glycemia, namely the concept of “glucose allostasis.” We examined whether glucose allostasis can be demonstrated using oral glucose tolerance tests (OGTTs) and the effects of the dynamics of β-cell demand on longitudinal changes of glucose tolerance in obese youth.

RESEARCH DESIGN AND METHODS— A cross-sectional analysis of 784 OGTTs of obese youth was used to demonstrate the concept of allostasis, and a longitudinal assessment of 181 subjects was used to examine the effects of changes in β-cell demand and the degree of obesity on glucose tolerance.

RESULTS— Glucose allostasis can be demonstrated using indexes derived from an OGTT. Increasing β-cell demand and the degree of obesity at baseline were independently related to elevations in ambient glycemia over time. Baseline BMI Z score was a significant contributor to elevated glucose levels on the second OGTT, while the change in degree of obesity during follow-up was not.

CONCLUSIONS— Increasing β-cell demand related to worsening insulin sensitivity and the degree of obesity per se have independent roles in the development of elevated glucose levels over time. This implicates that peripheral insulin sensitization and/or β-cell enhancement alongside a significant reduction in obesity may be needed to prevent the development of altered glucose metabolism in obese youth.
Insulin Sensitivity and Insulin Secretion Determined by Homeostasis Model Assessment and Risk of Diabetes in a Multiethnic Cohort of Women
Authors: Song Yiqing , Manson JoAnn E. , Tinker Lesley , Howard Barbara V. , Kuller Lewis H. , Nathan Lauren , Rifai Nader , Liu Simin
Published: June 2007

OBJECTIVE— The homeostasis model assessment (HOMA), based on plasma levels of fasting glucose and insulin, has been widely validated and applied for quantifying insulin resistance and β-cell function. However, prospective data regarding its relation to diabetes risk in ethnically diverse populations are limited.

RESEARCH DESIGN AND METHODS— Among 82,069 women who were aged 50–79 years, free of cardiovascular disease or diabetes, and participating in the Women's Health Initiative Observational Study, we conducted a nested case-control study to prospectively examine the relations of HOMA of insulin resistance (HOMA-IR) and β-cell function (HOMA-B) with diabetes risk. During a median follow-up period of 5.9 years, 1,584 diabetic patients were matched with 2,198 control subjects by age, ethnicity, clinical center, time of blood draw, and follow-up time.

RESULTS— Baseline levels of fasting glucose, insulin, and HOMA-IR were each significantly higher among case compared with control subjects, while HOMA-B was lower (all P values <0.0001). After adjustment for matching factors and diabetes risk factors, all four markers were significantly associated with diabetes risk; the estimated relative risks per SD increment were 3.54 (95% CI 3.02–4.13) for fasting glucose, 2.25 (1.99–2.54) for fasting insulin, 3.40 (2.95–3.92) for HOMA-IR, and 0.57(0.51–0.63) for HOMA-B. While no statistically significant multiplicative interactions were observed between these markers and ethnicity, the associations of both HOMA-IR and HOMA-B with diabetes risk remained significant and robust in each ethnic group, including whites, blacks, Hispanics, and Asians/Pacific Islanders. When evaluated jointly, the relations of HOMA-IR and HOMA-B with diabetes risk appeared to be independent and additive. HOMA-IR was more strongly associated with an increased risk than were other markers after we excluded those with fasting glucose ≥126 mg/dl at baseline.

CONCLUSIONS— High HOMA-IR and low HOMA-B were independently and consistently associated with an increased diabetes risk in a multiethnic cohort of U.S. postmenopausal women. These data suggest the value of HOMA indexes for diabetes risk in epidemiologic studies.
Electrooptical behaviour and control of a suspended particle device
Authors: Vergaz R. , Pena J. , Barrios D. , Pérez I. , Torres J.
Published: June 2007

A suspended particle device is made by electrophoretic rod-shape particles suspended in an organic gel. These particles can twist and order with an applied voltage. The light crossing the material suffers more or less scattering according to that voltage. A commercial device is analyzed in this work. Several electrical models are tested, being the best one a series configuration including a shunt double layer capacitance and a Warburg element. Main parameter errors are below 2%, showing the quality of this new electrical model for this kind of devices. A quick method to improve the manufacturing process on-line is also proposed. Impedance measurements will be fitted to the selected electrical model, in order to check physical aspects such as charge diffusion lengths and response times. An electronic driver to obtain several levels of device transmission has been also developed, being its linearity demonstrated too. Colour changes are negligible for the main part of the bleaching process. All these features allow the use of this set in domotics application.
Evaluating Accessibility of High-Altitude Valleys
Authors: Marcet Juan E. , Altamira Aníbal L. , Bustos Marcelo G. , Cordo Oscar V. , Mancini Pablo Girardi , Fernández Oscar Mario , Pereyra Miguel O.
Published: June 2007

The high-altitude mountain valleys of Calingasta, located in the province of San Juan, central western Argentina, along the border with Chile, are isolated and scarcely populated territories, rich in natural resources, scenic attractions, and grazing land. In spite of its economic potential, the development of the region has barely begun. A methodology is described that is designed to analyze accessibility to such valleys by roads located almost entirely in high mountain zones. A comprehensive study of regional resources was first developed, and the main sites of interest related to tourism, mining, and historical attractions were clearly identified. Alternative paths for the access roads were then traced following balanced criteria that considered not only the distance from the roads to sites of interest but also the real possibilities constrained by the complex topography of the area. In this study, maps, aerial photos, satellite images, and modern computational tools were used to define the alignments of the roads. Expeditions were also made to gather topographic data and information on soils, natural profiles, drainage patterns, and other terrain aspects, with intensive collection and use of Global Positioning System data. Afterward, different access alternatives were designed and their costs estimated, and life-cycle cost analysis was performed to select the most convenient ones. This study is a significant contribution to the long-delayed development of a vast region located in the southwest frontier in the province of San Juan.
Evaluating Economically Justified Road Works Expenditures on Unpaved Roads in Developing Countries
Authors: Archondo-Callao Rodrigo
Published: June 2007

Unpaved roads require periodic road works to maintain road condition over time. These works, which require planning and economic justification, typically consist of routine maintenance, grading, spot regraveling, and regraveling activities. To help road agencies identify unpaved road sections that may be candidates for maintenance works, this paper presents the methodology of a typical analytical study applying the roads economic decision model for economic evaluation of unpaved roads, taking into account a main concern in developing countries—that is, defining a proper level of investments and quality of maintenance on unpaved roads compatible with the amount of traffic on the roads and the unit road user costs and road works costs in the country. The methodology computes economically justified levels of road investment and maintenance works expenditures. Results of the methodology should be considered a first screening process, and candidate roads that pass this first screening should be subject to further investigation that would include more rigorous economic assessment and evaluation of other aspects of the proposed expenditures, notably environmental and social aspects. The sample results derived should be considered no more than a first approximation of country-specific results. To obtain results for any country, the methodology should be replicated and adapted with refined country-specific data.
Asset Management Strategy for Unsealed Low-Volume Roads in New Zealand
Authors: Pidwerbesky Bryan , Hunt Simon , Douglas Robert A.
Published: June 2007

The majority of rural local roads in New Zealand are unsealed low-volume roads that require regular grading, and a contractor has developed an asset management strategy for unsealed roads. Key facets of this strategy included establishment of a companywide asset management team responsible for implementing the strategy, creation of a new senior management position dedicated to delivering this strategy, and integration of asset management principles and processes into normal business. This unsealed roads maintenance strategy identified the need for a low-cost, effective tool for roughness monitoring that quantitatively reflects the unsealed network condition and is not based on subjective perception, which is the current situation. After a review of all existing roughness measurement systems from around the world, the Opti-Grade system from Canada was acquired and is being used on unsealed road networks throughout New Zealand. An example of the benefits of outsourcing road maintenance to private contractors is the fact that it was the contractor that identified the need for a low-cost roughness measurement tool to provide an objective operational performance indicator for rural local roads, initiated the development described in this paper, and implemented its use. This paper explains the processes involved in developing and implementing this strategy and the benefits to both the road authority and the company.
Rapid Survey of Road Conditions to Determine Environmental Effects and Maintenance Needs
Authors: Mills Keith , Dent Liz , Cornell Jennie L.
Published: June 2007

Research shows that low-volume roads, including commonly studied forest roads, can have many effects on water quality and aquatic resources. The temporal and spatial relationships of these environmental effects are complex. Water quality sampling is costly, and results are difficult to link to specific road problems. Research results from other road systems or regions are often dated and not reflective of a well-maintained road system. Because most best management practices deal with new roads, a landscape-level survey is essential for understanding and managing the environmental effects of roads at a landscape or watershed scale. This rapid survey has been developed by using monitoring and research results. Metrics were developed to quantify the environmental effects of road systems: road location in relation to streams or slopes prone to landslide or erosion; stream crossing effects on fish passage; washout and diversion risk at stream crossings; percent of road system with hydrologic connection to streams; land area dedicated to roads and not growing forests; and general condition rating of the prism, surface, drainage system, drainage structures, and brush and weeds. This survey analyzes conditions on the ground and is organized in a database and linked spatially to a geographic information system. Application of this survey to three watersheds indicates that most serious problems are limited in extent and severity. Performance measures and benchmarks have been developed and evaluated on the basis of information drawn from this survey.
Watershed Sediment Reduction
Authors: Ford Stephen H. , Calvert Eugene C. , Dashiell Howard N.
Published: June 2007

Unpaved roads are a significant source of sediments that degrade aquatic habitats. During the 1990s, counties in northwestern California faced road maintenance challenges as they were required to reduce sediment produced by their facilities and operations in order to comply with new regulations implementing provisions of the U.S. Endangered Species Act and Clean Water Act. In 1997, five counties in the region joined forces to address this problem, particularly with respect to anadromous fish. Together they obtained grant funding to study the effect of their activities on salmonid populations, develop mitigations, and undertake improvements. This paper reviews the sediment reduction treatments and implementation strategies employed by Mendocino County at two case study sites. Both are on resource roads 14 to 20 ft wide experiencing typical summer volumes of fewer than 50 vehicles per day and annual rainfall exceeding 40 in. An erosion inventory identified these road sections as being significant sediment contributors within their respective watersheds. The sediment reduction projects were completed between August and October 2002 with the use of low-impact-to-hydrology designs modified to comply with AASHTO guidelines. Where these features could not be accommodated, standard best management practices for gravel roads were employed. Compared with adjacent, untreated sections of road, both project sites performed well during exceptionally wet winters. Maintenance requirements have been significantly reduced, and sediment delivery is estimated to be down 84% at one site. Grant funding made these projects cost-effective for the county, but more economical alternatives are suggested for locally funded projects.
Evaluation of Pavement Edge Lines on Narrow Highways with Low Traffic Volume in Louisiana
Authors: Sun Xiaoduan , Park Jaehyun , Tekell V. O. “Dean” , Ludington Nina S.
Published: June 2007

To address the question of whether the implementation of edge lines may have any negative safety effect on narrow rural two-lane highways with low traffic volume, a study was conducted to investigate the distribution of vehicles' lateral positions before and after the implementation of edge line markings. The data were collected at seven tangent and three curved sections on Louisiana rural two-lane highways where the pavement width is less than 22 ft and average daily traffic volume is between 86 and 1,855. The analysis results clearly show that after the implementation of edge lines, vehicles tended to move away from the pavement edge, which could lead to a reduction in run-off-road crashes—the most common type of crash on narrow two-lane highways. The analysis also shows that even though the counts of centerline crossings increased at several sites during the daytime, they did decrease at night, when the distribution of vehicles' lateral position is more centralized.
Thickness Design Method for Bituminous-Stabilized Aggregate-Surfaced Roads
Authors: Wilde W. James
Published: June 2007

Many low-volume roadways in the county road system in Minnesota consist of unpaved aggregate surfaces. It is the responsibility of the county engineer to make determinations regarding the design and maintenance of such roads, as well as determinations regarding specific criteria such as weight restrictions. One method used by several counties in Minnesota is to construct a bituminous-stabilized layer by adding several inches of new aggregate and stabilizing it with an engineered, water-based asphalt emulsion through mix-in-place methods. There is a need, however, for a design method to provide highway engineers and their staffs with technical backing for the designs selected. This paper describes the results of an ongoing research project to develop a design method for determining the required thickness of stabilized and unstabilized layers in this type of aggregate-surfaced road. The basic design method is based on the material properties and a correlation between layered elastic analysis, dynamic cone penetrometer testing, and falling weight deflectometer testing. Results of the materials testing and layered elastic analysis are presented, as well as the correlation between the analysis and measured falling weight deflection data. The load rating analysis uses the Minnesota Department of Transportation methodology of estimating load rating on low-volume roads on the basis of falling weight deflectometer data. This method of design will allow county and other agency engineers to determine the appropriate thickness of the stabilized layer in order to obtain the desired load rating.
Friction Reliability Criteria Applied to Horizontal Curve Design of Low-Volume Roads
Authors: De Solminihac Hernán E. , Echaveguren Tomas , Vargas Sergio
Published: June 2007

Design of road horizontal curves usually considers geometric characteristics and surface pavement condition by means of friction, superelevation, and speed equations in a deterministic point of view: a unique radius and superelevation are selected, considering a uniform behavior of drivers and pavement surface condition. However, empirical evidence shows that operating speed usually exceeds design speed when design speed is lower than 100 km/h. This means that the aggregated friction demand exceeds the design friction. The friction threshold and variability are not considered in design at the present time. Therefore, the designer does not know the remaining friction available and cannot estimate the margin of safety provided by the design. This problem is important in low-volume roads (LVRs) because the design speed usually considered is lower than 100 km/h. In this paper a methodology to design horizontal curves for LVRs is proposed, considering the variability of skid resistance, pavement texture, driver behavior, and geometric design elements. Critical speed is obtained for two conditions: consistency between design and operational conditions and consistency between friction thresholds considered for the pavement surface and operational condition. For this purpose, a reliability index is estimated by using the Hasofer–Lind method. Results show that a more realistic design is obtained when an aggregated friction demand based on driver behavior is considered. A good design is obtained when design speed ranges around 60 km/h and the standard deviation of curve radius is lower than 20% of the mean radius.
Design of Low-Volume Pavements against Rutting
Authors: Dawson Andrew R. , Kolisoja Pauli , Vuorimies Nuutti , Saarenketo Timo
Published: June 2007

Roads that connect remote communities to each other and to urban centers are essential for community survival, yet they often must be funded from a small taxation base. Because of their thin, often unsealed, construction, the pavements forming these roads typically fail by rutting. A simplified means of designing pavements against rutting that is usable by engineers in these remote locations is proposed. The causes of rutting are identified, and simple methods of material assessment suitable for use by local road engineers having limited resources are discussed. An advanced testing and analytical approach is reported that uses repeated load triaxial testing of aggregates and nonlinear finite element analysis of chip-sealed pavements. The results are used to develop a permissible stress approach for design purposes. This approach uses simple stress analysis, by chart and PC-based computations, with readily available in situ evaluation of materials.
Planning Roads for Darfur, Sudan
Authors: Betz Mathew J. , Bauman Richard D.
Published: June 2007

The province of Darfur, Sudan, has been in the news for several years because of civil unrest and the suffering of its population. The Darfur region is defined as the triangular area connecting El Fasher, Nyala, and Geneina (on the Chad border). The road system is rudimentary at best. Transport development in Darfur is more difficult than in other regions of the country because of its location at the western extreme of the country and its geologic complexity. Data are presented from the Sudan Road Survey, which is one of the best sources of geotechnical data needed for the planning of low-volume roads in Sudan. The fieldwork took 18 months and covered the central and northern portions of the country, from the Ethiopian border to westernmost Darfur and from the Nuba Mountains southwest of Khartoum to the Egyptian border. The aim was to produce basic engineering data for road design, including estimation of construction and maintenance costs. In addition, the original field logs contain personal commentary that provides insight into the difficulty of conducting field research in Sudan at that time.
Rebirth of Chip Sealing in Minnesota
Authors: Wood Thomas J. , Olson Roger C.
Published: June 2007

Chip sealing is a common form of pavement preservation used by most cities and counties and by the Minnesota Department of Transportation (MNDOT). MNDOT, working in partnership with the Minnesota Local Road Research Board, was able to rejuvenate the chip seal program in Minnesota. Efforts to improve the performance of chip sealing as a pavement preventive maintenance treatment are discussed. The discussion covers chip seal design, aggregate characteristics, and training efforts, and the successes of MNDOT, counties, and cities are documented.
Privatization of Low-Volume-Road Maintenance Management
Authors: Ahmad Tahir , Ahmad Juraidah , Hossain Mustaque
Published: June 2007

In 2001, the Malaysian government privatized the maintenance of its federal road network. The network was divided into four maintenance regions. The southern region consists of about 4,000 km of roads; of that, about 1,800 km is under the Federal Land Development Authority (FELDA) scheme. Under the privatization contract, the concessionaire is required to carry out periodic, routine, and emergency maintenance of all roads within the FELDA scheme. The implementation of the privatized maintenance management program for the low-volume road network is discussed. The current management program includes road condition data collection, maintenance strategy and pavement materials selection, and use of innovative pavement maintenance technology. Data collection is carried out by using a high-speed road data collection survey vehicle; structural assessment is made by using the falling weight deflectometer, coring and dynamic cone penetrometer, and a conventional visual condition survey. An inventory system was also developed. Components of this privatized maintenance contract are discussed in detail.
Improvement of Functional Designation of Low-Volume Roads by Dust Abatement in Lithuania
Authors: Zilioniene Daiva , Cygas Donatas , Juzenas Antanas Aloyzas , Jurgaitis Algirdas
Published: June 2007

Gravel pavement prevails in Lithuanian state roads of regional significance, which make up 69% of the total road network. Dustiness of gravel roads reduces visibility and hinders traffic safety. Natural gravel from deposits, the particle size distribution of which ranges widely, is used in most gravel pavement. The variation of the particle size distribution is typical of all gravel deposits of melting glacial waters and those of river genetic origin in Lithuania. Gravel deposits contain a small quantity of fine particles, and the quantity of large particles is sufficient. However, gravel becomes finer because of pavement wear, and the quantity of particles larger than 5 or 4 mm according to standard sieves reduces to between 24.6% and 37%. Fine particle content (fraction <0.06 mm) usually does not exceed 6%. This paper presents research into dust reduction on gravel roads through the use of bitumen emulsions, calcium chloride, and calcium lignosulfonate. It provides recommendations on the concentration of the materials to be used for dust reduction as well as their statistical characteristics. Issues related to the use of materials for dust reduction are discussed. To resolve these issues, a 2 × 2 experimental design was used in the analysis of absorbents. Mathematical modeling was used to define the effectiveness of calcium chloride and calcium lignosulfonate. Recommendations are made with regard to the use of these absorbents in applying the models. The necessity of using cationic emulsions is based on research into dust mineral composition. It is recommended that the estimate of the quantity of materials required for dust reduction take into account the material particles' surface area.
Development of a Methodology for Measurement of Vehicle Dust Generation on Unpaved Roads
Authors: Thenoux Guillermo , Bellolio Juan Pablo , Halles Felipe
Published: June 2007

This paper presents the results of a field study aimed at developing a methodology for measuring vehicle dust generation on an unpaved road. The methodology is based on the use of portable standard equipment known as Dust Mate. This equipment measures the number of particles per cubic centimeter for different particle sizes: particles less than 10, 2.5, and 1 μm in diameter. The methodology was developed to improve the management of unpaved roads and to study the performance of earth road dust suppressants. The Dust Mate equipment may be mounted in various types of vehicles, and measurements may be performed at various speeds. The equipment can record dust generation continuously and may be programmed to save the data for measurements over various time spans. This last feature will allow evaluation of short segments of the road (less than 10 m). The study was performed in three stages: determination of (a) the best design position of the equipment for different types of vehicles in combination with the effect of speed, (b) the repeatability of results for different operation parameters, and (c) the effectiveness of various dust suppressants. The research was done on test sections of unpaved mining and rural roads with different types of soil and surface conditions. The study indicates that the methodology developed for dust measurement with the Dust Mate equipment may be considered an improvement over the methods currently in use. The measurements are reliable, and the repeatability of the results is better than is required by today's standards.
Choosing the Best Site for a Bridge
Authors: Groenier James Scott , Gubernick Robert
Published: June 2007

The proper location for a bridge is as important as the characteristics of the bridge itself. This paper discusses a commonsense approach, combined with science, to help select the best locations for bridges. Problems associated with bridge location and construction can be alleviated by conducting a proper site investigation, paying attention to geomorphological indicators, and understanding road template design needs and how streams and watersheds function. Channel classification provides a simple framework to help understand the problems that may exist at bridge locations and to help with route locations. An interdisciplinary approach is required to incorporate all the considerations involved in choosing the best bridge location.
Comprehensive Field Studies to Address the Performance of Stabilized Expansive Clays
Authors: Puppala Anand J. , Pillappa Gautham S. , Hoyos Laureano R. , Vasudev Deepti , Devulapalli Deepti
Published: June 2007

This work was conducted as part of a research study for the City of Arlington, Texas, to explore and develop alternative stabilization methods for sulfate-rich soils located in southern parts of the city. As a result of a literature review of sulfate-rich expansive soil treatments and comprehensive laboratory studies, four stabilizers were recommended for field treatment studies: sulfate-resistant cement (Type V), low-calcium Class F fly ash with Type V cement, ground granulated blast furnace slag, and lime mixed with polypropylene fibers. The four stabilizers, along with control lime treatment, were used to modify subsoil near Harwood Road in South Arlington. Rigid pavements were then constructed on the stabilizers' sections, and these sections were instrumented with strain gauges and pressure cells. Pavement instrumentation was then monitored to address load transfer mechanisms and stabilized materials' compression behavior under traffic loads. Elevation surveys were also conducted to evaluate swell movements of the treated subsoils. X-ray diffraction analyses were conducted on treated subgrade specimens to address the formation of ettringite mineral. On the basis of these evaluations, the performance of the four stabilization methods was compared with that of the control lime section.
Mixing Efficiency for Stabilized Subgrades for Low-Volume Roads
Authors: Parsons Robert L. , O'Connor Molly S. , Cross Stephen A.
Published: June 2007

Lime is widely used to stabilize fine-grained subgrades beneath pavements. The procedure used to apply lime and the effectiveness of the mixing stage can have a significant impact on the quality of the stabilized sub-grade. For this study, lime was applied to two test sections in slurry and quicklime forms and samples were taken at various stages of mixing. Strength values were determined for field- and laboratory-mixed samples. Strength and stiffness of the subgrades were tracked for up to 33 days by using the dynamic cone penetrometer and soil stiffness gauge. Results showed that additional mixing reduced average lump size, particularly when conducted after a mellowing stage, and significantly improved the subgrade for up to at least four passes. Strengths also increased substantially with time for the stabilized soil, and long-term strengths were highest for soils mixed wet of optimum moisture.