bluuebunny/crossref_metadata_2025 huggingface dataset:
Developmental Impacts of Heavy Metals and Undernutrition
Authors: Wasserman Gail A. , Liu Xinhua , Factor‐Litvak Pam , Gardner Julie Meeks , Graziano Joseph H.
Published: September 2010

Abstract:  A recent Lancet series highlighted enormous loss to young children's developmental potential in developing countries, from exposure to sociocultural and health risks. The possibility that nutritional deficiencies might exacerbate the adverse impact of environmental exposures to developmental toxicants such as heavy metals and pesticides has not been explored. While both arsenic and manganese exposures have known neurotoxicity in adults, systematic investigation in young children has only recently begun. Five hundred and ninety 6‐ and 10‐year‐old Bangladeshi children participated in three overlapping studies. Well‐water arsenic and manganese were measured from home wells; urine and blood samples were provided; and sociodemographic and household characteristics obtained. For new analyses, ‘stunting’ was defined as 2 or more standard deviations below the Centers for Disease Control and Prevention gender‐specific height‐for‐age norms. Developmental assessments employed culturally adapted variants of the WISC‐III (age 10) or WPPSI‐III (age 6). In prior analyses, after adjusting for social factors, well‐water arsenic and manganese were both significantly associated with poorer developmental scores at age 10; associations for water arsenic at 6 years were significant, but attenuated. Negative associations with metal exposures held up in newer analyses, and stunting was significantly associated with lower intellectual functioning in analyses considering either metal. There were no significant stunting‐by‐metal interactions. Developmental risks often co‐occur. Millions in South Asia are exposed to naturally occurring arsenic and manganese through household wells. Stunting affects more than 25% of young children in developing countries. The combined neurocognitive loss from both risks, although rarely jointly studied, represents a substantial loss of global potential.
Developmental Origins of Adult Health and Disease: The Role of Periconceptional and Foetal Nutrition
Authors: McMillen I. Caroline , MacLaughlin Severence M. , Muhlhausler Beverly S. , Gentili Sheridan , Duffield Jaime L. , Morrison Janna L.
Published: September 2010

Abstract:  The ‘developmental origins of adult health and disease’ hypothesis stated that environmental factors, particularly maternal undernutrition, act in early life to programme the risks for adverse health outcomes, such as cardiovascular disease, obesity and the metabolic syndrome in adult life. Early physiological tradeoffs, including activation of the foetal hypothalamo–pituitary–adrenal (HPA) axis, confer an early fitness advantage such as foetal survival, while incurring delayed health costs. We review the evidence that such tradeoffs are anticipated from conception and that the periconceptional nutritional environment can programme the developmental trajectory of the stress axis and the systems that maintain and regulate arterial blood pressure. There is also evidence that restriction of placental growth and function, results in an increased dependence of the maintenance of arterial blood pressure on the sequential recruitment of the sympathetic nervous system and HPA axis. While the ‘early origins of adult disease’ hypothesis has focussed on the impact of maternal undernutrition, an increase in maternal nutritional intake and in maternal body mass intake has become more prevalent in developed countries. Exposure to overnutrition in foetal life results in a series of central and peripheral neuroendocrine responses that in turn programme development of the fat cell and of the central appetite regulatory system. While the physiological responses to foetal undernutrition result in the physiological trade off between foetal survival and poor health outcomes that emerge after reproductive senescence, exposure to early overnutrition results in poor health outcomes that emerge in childhood and adolescence. Thus, the effects of early overnutrition can directly impact on reproductive fitness and on the health of the next generation. In this context, the physiological responses to relative overnutrition in early life may directly contribute to an intergenerational cycle of obesity.
International Society for Sexual Medicine’s Guidelines for the Diagnosis and Treatment of Premature Ejaculation
Authors: Althof Stanley E. , Abdo Carmita H.N. , Dean John , Hackett Geoff , McCabe Marita , McMahon Chris G. , Rosen Raymond C. , Sadovsky Richard , Waldinger Marcel , Becher Edgardo , Broderick Gregory A. , Buvat Jacques , Goldstein Irwin , El-Meliegy Amr I. , Giuliano Francois , Hellstrom Wayne J.G. , Incrocci Luca , Jannini Emmanuele A. , Park Kwangsung , Parish Sharon , Porst Hartmut , Rowland David , Segraves Robert , Sharlip Ira , Simonelli Chiara , Tan Hui Meng
Published: September 2010

Introduction

Over the past 20 years our knowledge of premature ejaculation (PE) has significantly advanced. Specifically, we have witnessed substantial progress in understanding the physiology of ejaculation, clarifying the real prevalence of PE in population-based studies, reconceptualizing the definition and diagnostic criterion of the disorder, assessing the psychosocial impact on patients and partners, designing validated diagnostic and outcome measures, proposing new pharmacologic strategies and examining the efficacy, safety and satisfaction of these new and established therapies. Given the abundance of high level research it seemed like an opportune time for the International Society for Sexual Medicine (ISSM) to promulgate an evidenced-based, comprehensive and practical set of clinical guidelines for the diagnosis and treatment of PE.

Aim

Develop clearly worded, practical, evidenced-based recommendations for the diagnosis and treatment of PE for family practice clinicians as well as sexual medicine experts.

Method

Review of the literature.

Results

This article contains the report of the ISSM PE Guidelines Committee. It affirms the ISSM definition of PE and suggests that the prevalence is considerably lower than previously thought. Evidence-based data regarding biological and psychological etiology of PE are presented, as is population-based statistics on normal ejaculatory latency. Brief assessment procedures are delineated and validated diagnostic and treatment questionnaires are reviewed. Finally, the best practices treatment recommendations are presented to guide clinicians, both familiar and unfamiliar with PE, in facilitating treatment of their patients.

Conclusion

Development of guidelines is an evolutionary process that continually reviews data and incorporates the best new research. We expect that ongoing research will lead to a more complete understanding of the pathophysiology as well as new efficacious and safe treatments for this sexual dysfunction. Therefore, it is strongly recommended that these guidelines be re-evaluated and updated by the ISSM every 4 years.
STUDIES IN SOIL FUMIGATION: DISTRIBUTION OF CARBON DISULPHIDE IN SOIL FUMIGATED UNDER VARIOUS CONDITIONS
Authors: HIGGINS J. C. , POLLARD A. G.
Published: September 2010

Experiments on the lines indicated in the preceding paper but with improved methods confirm that the depth‐distribution of carbon disulphide in soil fumigated by injection is characterized by:

A high concentration in the zone of injection and immediately below it.

A rapid decrease in concentration as the surface is approached.

A somewhat slower decrease with depth below the zone of injection.

A time‐concentration curve for each individual layer representing a sharp rise to a maximum concentration followed by a slower decline to a low level which is normally reached in about 24 hours.

Variations in the depth of injection raise or lower the zone of high concentrations without appreciably affecting that in the surface 0–3 in. layer.

Increased amounts of carbon disulphide per injection increase the persistence of the effective concentrations of fumigant, without causing any marked change in distribution or in the maximum concentrations attained.

Experimental data indicate that the loss of fumigant from treated soil occurs very largely via the soil surface.

Effective concentrations of carbon disulphide could not be produced in the surface layer by variation of the depth or amount of the injections nor by covering the surface with sacking.

The nature of the concentration gradients of carbon disulphide in soil suggests that movement of the vapour is largely a simple diffusion process, but that in coarse textured or loosely packed soils a gravitational flow (as of a viscous fluid) may occur to a limited extent. There is no evidence that such gravitational flow proceeds to any considerable extent. The concentration of carbon disulphide is uniformly low at all depths after about 24 hours.
The Multiple‐Infection Transformation
Authors: Gregory P. H.
Published: September 2010

Attention is drawn to the possibility of misinterpreting results which may arise when the incidence of an organism, or any other event, is expressed as percentage presence or absence on plots of standard area. Disease gradients when expressed as percentage presence are shown to be artificially flattened. The amount of flattening depends on incidence of the disease and the size of plot chosen. A table is given by which the necessary transformation can be made when the organism or event is distributed at random. Examples are given of leaf diseases: (1) distributed at random (Phytophthora infestans); and (2) aggregated (Gymnosporangium juniperivirginianae and G. clavariaeforme). Methods of detecting and measuring aggregation are briefly discussed.
Reproductive Biology of Erythrina falcata (Fabaceae: Papilionoideae)1
Authors: Etcheverry Angela V. , Alemán Carlos E. Trucco
Published: September 2010

Reproductive phenology, floral biology, degree of self‐incompatibility, and floral visitors of Erythrina falcata were studied in an Argentinean population. Flowering occurs during the dry season from late August to late October. Flower lifetime is 5–6 d. Phylogenetic studies indicate that E. falcata, together with E. fusca and E. crista‐galli, are included in a basal clade within Erythrina. Its phylogenetic position, floral morphology, and nectar characteristics suggest a hummingbird–passerine mixed pollination system. The flowers are nontubular, and the vexillum (the upper petal of the corolla) covers the other remaining floral parts until displaced by a visiting passerine (Icterus cayanensis) or a hummingbird (Amazilia chionogaster). Both birds act as pollen vectors. Bees were observed as occasional pollinators. Nectar production begins at anther dehiscence and coincides with maximum stigmatic receptivity. The base of the keel forms a secondary nectar reservoir. Controlled pollinations showed that this species is self‐incompatible, although a few fruits develop from selfing. Pollen:ovule ratio (43,200:7) is as expected for a xenogamous plant. Only 1 percent of the flowers set seeds under natural conditions. Possible explanations for the low reproductive success are discussed.
Woody Debris in the Mangrove Forests of South Florida1
Authors: Krauss Ken W. , Doyle Thomas W. , Twilley Robert R. , Smith Thomas J. , Whelan Kevin R.T. , Sullivan Jason K.
Published: September 2010

Woody debris is abundant in hurricane‐impacted forests. With a major hurricane affecting South Florida mangroves approximately every 20 yr, carbon storage and nutrient retention may be influenced greatly by woody debris dynamics. In addition, woody debris can influence seedling regeneration in mangrove swamps by trapping propagules and enhancing seedling growth potential. Here, we report on line‐intercept woody debris surveys conducted in mangrove wetlands of South Florida 9–10 yr after the passage of Hurricane Andrew. The total volume of woody debris for all sites combined was estimated at 67 m3/ha and varied from 13 to 181 m3/ha depending upon differences in forest height, proximity to the storm, and maximum estimated wind velocities. Large volumes of woody debris were found in the eyewall region of the hurricane, with a volume of 132 m3/ha and a projected woody debris biomass of approximately 36 t/ha. Approximately half of the woody debris biomass averaged across all sites was associated as small twigs and branches (fine woody debris), since coarse woody debris >7.5 cm felled during Hurricane Andrew was fairly well decomposed. Much of the small debris is likely to be associated with post‐hurricane forest dynamics. Hurricanes are responsible for large amounts of damage to mangrove ecosystems, and components of associated downed wood may provide a relative index of disturbance for mangrove forests. Here, we suggest that a fine:coarse woody debris ratio ≤0.5 is suggestive of a recent disturbance in mangrove wetlands, although additional research is needed to corroborate such findings.
Epigaeic Invertebrates as Potential Ecological Indicators of Afromontane Forest Condition in South Africa1
Authors: Lawes Michael J. , Kotze D. Johan , Bourquin Sven L. , Morris Craig
Published: September 2010

Forest condition and the associated ecological processes vital for forest patch persistence are difficult to judge rapidly and time‐consuming to sample. Here we examine the efficacy of epigaeic invertebrate species as ecological indicators of Afromontane forest condition. Epigaeic invertebrates are potentially good ecological indicators because they play an important role in maintaining ecosystem processes, such as nutrient cycling, rely almost entirely upon the resources provided by the organic leaf litter layer, are known to be sensitive to environmental changes, and are easily surveyed. Epigaeic invertebrate communities were sampled using pitfall traps for 21 days in each of 11 forests that spanned a gradient from large and relatively undisturbed to small and highly disturbed forest patches. Using canonical correspondence analysis, we identified a suite of potential ecological indicator species (eight out of 140 species) and showed that gradients in their population response (abundance) reflect overall forest condition, as judged from the correlated vegetation indicators and position of the forests of varying condition along this gradient. The abundance of all but two of the eight indicator species (a spider and the landhopper,Talitriator africana[Amphipoda]) decreased with increasing disturbance. As a group, the rove beetles (Staphylinidae) show promise as ecological indicators and comprised four of the eight potential indicators species. A strong case is also made for a single‐species ecological indicator in the form ofT. africana, which is a robust and sensitive indicator of poor forest condition.
Introduction to the Special Section: Emerging Adulthood Around the World
Authors: Arnett Jeffrey Jensen , Eisenberg Nancy
Published: September 2010

ABSTRACT—
Cultural variation is an important question to address with regard to emerging adulthood. Summarized briefly are the contents of the Special Section, including a debate on the theory of emerging adulthood and six articles on emerging adulthood as it appears among various populations in Asia, Latin America, Europe, and the United States.
Emerging Adulthood: What Is It, and What Is It Good For?
Authors: Arnett Jeffrey Jensen
Published: September 2010

ABSTRACT—
This article asserts that the theory of emerging adulthood is a useful way of conceptualizing the lives of people from their late teens to their mid‐ to late 20s in industrialized societies. The place of emerging adulthood within the adult life course is discussed. The weaknesses of previous terms for this age period are examined, and emerging adulthood is argued to be preferable as a new term for a new phenomenon. With respect to the question of whether emerging adulthood is experienced positively or negatively by most people, it is argued that it is positive for most people but entails developmental challenges that may be difficult and there is great heterogeneity, with some emerging adults experiencing serious problems. With respect to the question of whether or not emerging adulthood is good for society, it is argued that claims of the dangers of emerging adulthood are overblown, but emerging adulthood is probably a mixed blessing for society.
Emerging Adulthood in Argentina: An Age of Diversity and Possibilities
Authors: Facio Alicia , Resett Santiago , Micocci Fabiana , Mistrorigo Clara
Published: September 2010

ABSTRACT—
This article examines the nature of emerging adulthood in Argentina. Arnett defines emerging adulthood as the period of development bridging adolescence and young adulthood during which people are no longer adolescents but have not yet attained full adult status. This period ranges from the late teens through the 20s, with a focus on ages 18 through 25. This period is characterized by frequent change as young people explore various possibilities in love, work, and worldviews. According to studies carried out in the United States, emerging adults do not view themselves as adolescents but many of them do not view themselves entirely as adults either.
Comment on Warshak: The Approximation Rule as a Work in Progress
Authors: Atwood Barbara Ann
Published: September 2010

ABSTRACT—
This commentary on Warshak’s article on the American Law Institute’s approximation standard emphasizes that the standard provides parents with a concrete framework for negotiation and is likely to be a valuable resource for courts and policymakers. It also highlights the fact that by focusing on actual parenting conduct, the standard is designed to replicate individual family choices and will necessarily reflect broader changes in the American family, including evolving approaches to fatherhood. Although quantity of caretaking may not be a valid proxy for quality of attachment in all cases, it is preferable in many cases to the indeterminate and subjective best‐interests test.
The “Approximation Rule”: Another Proposed Reform That Misses the Target
Authors: Lamb Michael E.
Published: September 2010

ABSTRACT—
In his article on the approximation rule, Warshak correctly notes both that the rule is unlikely to minimize the adverse effects of parents’ separation on their children’s adjustment and that it misrepresents the relevant social science literature. More specifically, the rule is unlikely to reduce either the level of conflict between parents or their children’s harmful exposure to it, mistakenly confuses the amount of parent–child time with parental commitment, and ignores the difficulties inherent in measuring not only the amounts of time spent in caregiving but also other fundamental aspects of parental involvement and importance. For these reasons, it does not represent an improvement over the “best‐interests standard” it seeks to replace.
Systolic Time Ratio by Impedance Cardiography to Distinguish Preserved vs Impaired Left Ventricular Systolic Function in Heart Failure
Authors: Thompson Brenda , Drazner Mark H. , Dries Daniel L. , Yancy Clyde W.
Published: September 2010

Left ventricular ejection fraction (EF) is used to assess patients with heart failure (HF); however, frequent measurements are not cost‐effective. Impedance cardiography (ICG) is a low‐cost, noninvasive test that measures systolic time intervals and may be a method for detecting impaired vs intact EF. This study evaluated the relationship between EF by echocardiography or gated nuclear ventriculography and systolic time ratio (STR) by ICG in outpatients with chronic HF. A retrospective chart review identified 52 patients with EF and STR measured within 2 weeks. There was an inverse correlation between STR and EF (r=−0.54; P<.001). The area under the receiver operating characteristic curve for STR to identify reduced EF was 0.86. An EF ≤50% and STR ≥0.50 demonstrated 93% sensitivity and 85% specificity. STR was able to distinguish intact (>50%) from impaired EF (≤50%). STR by ICG has the potential to be a reliable method to monitor ventricular function in chronic HF.
Models of funding and reimbursement in health care: A conceptual framework
Authors: Deber Raisa , Hollander Marcus J. , Jacobs Philip
Published: September 2010

Abstract: What is the best way to pay providers to deliver health services? The research evidence strongly suggests that there is no single answer; rather, one must consider the incentives and disincentives inherent in alternative health‐care funding models. This article suggests a conceptual framework for categorizing payment mechanisms that highlights different policy options and their associated tradeoffs. It concentrates on the following: distinctions between need, demand, and utilization as they affect the rationale for government involvement; models of the possible funding flows (two‐way, three‐way, and four‐way) as they affect policy levers; and implications of various approaches to payment. The framework is then used to clarify the advantages and disadvantages of particular approaches to financing health care and to clarify the tradeoffs involved.

Sommaire:
Quel est le meilleur moyen de payer les fournisseurs pour leur prestation de services de santé? Les données probantes de la recherche laissent fortement entendre qu'il n'existe pas une seule et unique réponse; il faut plutôt tenir compte des incitatifs et des désincitatifs inhérents aux autres modèles de financement des soins de santé. Pour classer par catégories les mécanismes de paiement, le présent article propose un cadre conceptuel qui souligne différentes options de politiques et les compromis qui leur sont associés. Il se concentre sur : les distinctions entre besoin, demande et utilisation qui ont une incidence sur la justification de l'intervention du gouvernement; les modèles des flux de financement possibles (à deux, trois et quatre directions) qui ont une incidence sur les leviers politiques; et les implications de diverses approches à l'égard du paiement. Le cadre est alors utilisé pour préciser les avantages et les inconvénients des approches particulières concernant le financement des soins de santé, et pour clarifier les compromis impliqués.
Re‐thinking local autonomy: Perceptions from four rural municipalities
Authors: Jacob Benoy , Lipton Becky , Hagens Victoria , Reimer Bill
Published: September 2010

Abstract: Led by larger urban municipalities, the current municipal reform agenda in Canada places considerable emphasis on the issue of local autonomy. This article looks at how this agenda might affect smaller rural municipalities, since the assumption seems to be that one can simply re‐size and re‐shape policy prescriptions from urban and suburban contexts to fit rural areas. Drawing on the lessons learned from an eight‐year project titled “Understanding the New Rural Economy: Options and Choices,” the authors argue that autonomy is only valuable in relation to a locality's capacity to take advantage of new powers and that rural capacities are very different from those of their urban counterparts. The authors present a conceptual framework in which capacity is a dynamic and multidimensional entity of which autonomy is a necessary, though not sufficient, condition. This framework is then employed to explore four rural Canadian municipalities. This study is the first to consider traditional administrative reforms in a rural context. Employing a case‐study methodology, the authors found four dimensions of capacity that may support changes to local autonomy: strategic planning, citizen participation and support, expertise, and access to revenues.

Sommaire :
Dirigé par les plus grandes municipalités urbaines, le programme actuel des réformes municipales au Canada met une emphase considérable sur la question de l'autonomie locale. Le présent article porte sur la manière dont ce programme pourrait avoir une incidence sur les plus petites municipalités rurales, étant donné que l'hypothèse semble être qu'il est tout simplement possible de redimensionner et refondre les prescriptions de politiques de contextes urbains et suburbains pour qu'elles s'adaptent aux régions rurales. Tirant des enseignements d'un projet sur huit ans intitulé“Comprendre la nouvelle économie rurale : options et choix” (NER), l'article prétend que l'autonomie est seulement intéressante en ce qui concerne la capacité d'une localitéà tirer parti de nouveaux pouvoirs et que les capacités rurales sont très différentes des capacités urbaines. Les auteurs présentent un cadre conceptuel où la capacité est une entité dynamique et multi‐dimensionnelle dont l'autonomie est une condition nécessaire mais pas suffisante. Ce cadre est alors employé pour étudier à fond quatre municipalités rurales canadiennes. L'article est la première étude à envisager les réformes administratives traditionnelles dans un contexte rural. Ayant recours à une méthodologie d'études de cas, les auteurs ont trouvé quatre dimensions de capacité qui peuvent soutenir des changements pour l'autonomie locale : la planification stratégique, la participation et le soutien des citoyens, l'expertise et l'accès aux revenus.
Species‐specific primers for the identification of the ectomycorrhizal fungus Tuber macrosporum Vittad.
Authors: BENUCCI G. M. N. , RAGGI L. , DI MASSIMO G. , BACIARELLI‐FALINI L. , BENCIVENGA M. , FALCINELLI M. , ALBERTINI E.
Published: September 2010

Limitations in the use of morphological traits to identify ectomycorrhizae have led to the development of species‐specific molecular markers. Herein, we report a PCR‐based technique for the reliable molecular identification of the ectomycorrhizal fungus Tuber macrosporum Vittad. Species‐specific primers were designed from an alignment of internal transcribed spacer rDNA sequences from Tuber spp. and from the most common ectomycorrhizal contaminants found in the root systems of truffle‐infected plants. The primers were tested for selective amplification using both different truffles and different ectomycorrhizae and were found to identify T. macrosporum successfully. The application of the primers in certifying the quality of truffle‐inoculated seedlings is discussed.
The deceptive nature of UVA tanning versus the modest protective effects of UVB tanning on human skin
Authors: Miyamura Yoshinori , Coelho Sergio G. , Schlenz Kathrin , Batzer Jan , Smuda Christoph , Choi Wonseon , Brenner Michaela , Passeron Thierry , Zhang Guofeng , Kolbe Ludger , Wolber Rainer , Hearing Vincent J.
Published: September 2010

The relationship between human skin pigmentation and protection from ultraviolet (UV) radiation is an important element underlying differences in skin carcinogenesis rates. The association between UV damage and the risk of skin cancer is clear, yet a strategic balance in exposure to UV needs to be met. Dark skin is protected from UV‐induced DNA damage significantly more than light skin owing to the constitutively higher pigmentation, but an as yet unresolved and important question is what photoprotective benefit, if any, is afforded by facultative pigmentation (i.e. a tan induced by UV exposure). To address that and to compare the effects of various wavelengths of UV, we repetitively exposed human skin to suberythemal doses of UVA and/or UVB over 2 weeks after which a challenge dose of UVA and UVB was given. Although visual skin pigmentation (tanning) elicited by different UV exposure protocols was similar, the melanin content and UV‐protective effects against DNA damage in UVB‐tanned skin (but not in UVA‐tanned skin) were significantly higher. UVA‐induced tans seem to result from the photooxidation of existing melanin and its precursors with some redistribution of pigment granules, while UVB stimulates melanocytes to up‐regulate melanin synthesis and increases pigmentation coverage, effects that are synergistically stimulated in UVA and UVB‐exposed skin. Thus, UVA tanning contributes essentially no photoprotection, although all types of UV‐induced tanning result in DNA and cellular damage, which can eventually lead to photocarcinogenesis.
Apgar score and dental caries risk in the primary dentition of five year olds
Authors: Sanders AE , Slade GD
Published: September 2010

Background:  Conditions in utero and early life underlie risk for several childhood disorders. This study tested the hypothesis that the Apgar score predicted dental caries in the primary dentition.

Methods:  A retrospective cohort study conducted in 2003 examined associations between conditions at birth and early life with dental caries experience at five years. Dental examination data for a random sample of five‐year‐old South Australian children were obtained from School Dental Service electronic records. A questionnaire mailed to the parents obtained information about neonatal status at delivery (five‐minute Apgar score, birthweight, plurality, gestational age) and details about birth order, weaning, and behavioural, familial and sociodemographic characteristics.

Results:  Of the 1398 sampled children with a completed questionnaire (response rate = 64.6%), 1058 were singleton term deliveries among whom prevalence of dental caries was 40.1%. In weighted log‐binomial regression analysis, children with an Apgar score of <=8 relative to a score of 9–10 had greater probability of dental caries in the primary dentition after adjusting for sociodemographic and behavioural covariates and water fluoridation concentration (adjusted PR = 1.47, 95% CI = 1.11, 1.95).

Conclusions:  Readily accessible markers of early life, such as the Apgar score, may guide clinicians in identifying children at potentially heightened risk for dental caries and aid decision‐making in allocating preventive services.
In vivo effects of amorphous calcium phosphate‐containing orthodontic composite on enamel demineralization around orthodontic brackets
Authors: Uysal T , Amasyali M , Ozcan S , Koyuturk AE , Akyol M , Sagdic D
Published: September 2010

Background:  The aim of this study was to evaluate the in vivo effects of an amorphous calcium phosphate‐containing orthodontic composite in reducing enamel demineralization around orthodontic brackets, and to compare it with the control.

Methods:  Fourteen orthodontic patients were divided into two equal groups. They received brackets fitted to all first premolars, bonded with either Aegis Ortho® (The Bosworth Co.), an ACP‐containing orthodontic composite (experimental group), or Concise® (3M Dental Products), a resin‐based orthodontic composite (control group). After 30 days, the teeth were extracted and longitudinally sectioned, and evaluated by superficial‐microhardness analysis. The determinations were made at the bracket edge cementing limits and at occlusal and cervical points 100 and 200 μm away from the edge. In all of these positions, indentations were made at depths of 10, 20, 30, 50, 70, and 90 μm from the enamel surface. Analysis of variance (ANOVA) and Tukey post hoc test was used. The statistical significance level was set at p <0.05.

Results:  The ANOVA showed statistically significant differences for position, material, depth, and their interactions (p <0.001). The multiple comparison test showed that the ACP‐containing orthodontic composite was significantly more efficient than the control composite, reducing enamel demineralization in almost all evaluations (p <0.001).

Conclusions:  Present results indicated that ACP‐containing orthodontic composite for bonding orthodontic brackets successfully inhibited demineralization in vivo. This effect was localized to the area around the brackets and was statistically significant after 30 days.
University postgraduate training in implant dentistry for the general dental practitioner#
Authors: Ivanovski S , Mattheos N , Scholz S , Heitz‐Mayfield L
Published: September 2010

Aims of This Paper

This paper aims to:

(1) Describe the educational requirements of general practitioners who want to safely and effectively introduce implant dentistry procedures to their practice.

(2) Define the necessary competencies and level of complexity that would need to be attained in a postgraduate implant dentistry programme for general dental practitioners.

(3) Discuss the programme structures which universities can utilize in order to provide quality education in implant dentistry for general practitioners.

(4) Provide guidelines for the resources, content, course format and instructional methods which could be well suited to the educational requirements of such programmes.

The authors intend to produce a headline reference guide to outline the necessary educational structures for postgraduate pathways aimed at facilitating the continuous professional development of general practitioners within implant dentistry. This paper does not address issues concerning specialist training or higher research degrees.
Large Amplitude Free Vibration of a Rotating Nonhomogeneous Beam With Nonlinear Spring and Mass System
Authors: Chakrabarti A. , Ray P. C. , Bera Rasajit Kumar
Published: September 2010

This paper investigates the free out of plane vibration of a rotating nonhomogeneous beam with nonlinear spring and mass system. The effect of nonhomogeneity of the beam appears both in the governing equations and in the boundary conditions, but the nonlinear spring-mass effect appears in the boundary conditions only. The solution is obtained by applying the method of multiple time scales directly to the nonlinear partial differential equations and the boundary conditions. The results of the linear frequencies match well with those obtained in open literature. The effect of the nonhomogeneity of the stiffer beam (β=0.01) reduces the frequencies of vibration of the beam. A possible physical explanation of this reduced frequency of the nonhomogeneous beam is discussed. A subsequent nonlinear study of the nonhomogeneous beam indicates that the mass of the spring and its location also have a pronounced effect on the vibration of the beam. The effect of the nonhomogeneity of the beam on the relative stability of the nonlinear vibration of the beam with spring-mass system is also studied.
Topological Information Content and Expressiveness of Function Models in Mechanical Design
Authors: Sen Chiradeep , Summers Joshua D. , Mocko Gregory M.
Published: September 2010

In this paper, two approaches for computing the topological information content of function models in mechanical engineering design are developed and compared. Previously, a metric for computing information content of functions and flows within function models was proposed. Here, this metric is evolved to include the information contained in the connections between flows and functions in a function model. The first approach is based on uniform unconditional probability of a flow connecting any two functions within the model. The second approach is based on additional knowledge that the functions and flows in a model have limited compatibility, thereby, reducing the choices for origin and destination functions for each flow. This additional knowledge is represented using a new graphical representation supported by syntactic grammar rules. Both approaches are then applied to an example function model. Comparison between the approaches shows that the inclusion of this additional knowledge increases the expressiveness by reducing the uncertainty associated with function models.
A System Framework With Online Monitoring and Evaluation for Design Evolution of Engineering Systems
Authors: Gamage L. B. , de Silva C. W.
Published: September 2010

This paper presents a methodology for the design evolution of engineering systems, with a mechatronic emphasis. The developed approach specifically integrates machine health monitoring and an expert system and carries out the design evolution of a multidomain dynamic system using bond graph modeling and genetic programming. The evolution of a bond graph model of a mechatronic system through genetic programming enables the exploration of the design space, thereby generating a global optimum design solution in an automated manner. Domain knowledge and expertise are used to control the design exploration and to restrict it only to a meaningful design space. As an illustrative example, the developed methodology is applied to redesign the electrohydraulic manipulator of an existing industrial fish processing machine.
A Method for Function Dividing in Conceptual Design by Focusing on Linguistic Hierarchal Relations
Authors: Yamamoto Eiko , Taura Toshiharu , Ohashi Shota , Yamamoto Masaki
Published: September 2010

In this study, we attempted to develop a method that applies the notion and technology of natural language processing for operating a function dividing process in conceptual design. We formulated a function dividing process from a linguistic viewpoint and constructed linguistic hierarchal structures in this process. This method is significant in identifying hierarchal relationships between the upper- and lower-level functions from the viewpoint of linguistic hierarchal relations. An experiment was carried out to confirm whether the proposed methods were feasible and whether the extracted relations were meaningful for supporting the function dividing process.
A Constraint-Based Approach to the Composition Relation Management of a Product Class in Design
Authors: Yvars Pierre-Alain
Published: September 2010

The choice of solution, which a systems architect is confronted with within the framework of a product structure definition, can very quickly prove to be a thorny problem owing to the possible combinatorial system. In this paper, we will offer an alternative resting on the utilization of constraint-based programming techniques for representing and managing such complexity. More precisely, we will dwell on the presentation of a constraint-based approach to the composition relation management of a product class in design. After setting forth all the potential of the constraint-based approach, we will formally explain, in more detail, the six types of relations that seem to be essential to building a class of products. The approach is based on a three-level architectural model. The first level concerns the product model as such, the second supplies a formal representation of this model, whereas the third consists of rendering an arithmetic constraint-based approach to the intermediate model. We will use the discrete constraint satisfaction problems for operating and solving the latter. Our overall approach, from product modeling to resolution, is intended to be a generic one and the case in point will be the design of a functional pivot link between a connecting rod and a piston. The architect can subsequently make his own choices and the tool will automate their propagation by means of the constraint network modeling the problem. A dimensioning architectural model is, thus, obtained in compliance with the original list of requirements.
A New Design Rationale Representation Model for Rationale Mining
Authors: Liu Ying , Liang Yan , Kwong Chun Kit , Lee Wing Bun
Published: September 2010

The management of design rationale (DR) in engineering design is an important task since DR is often regarded as crucial information in design decision support and design analysis. The existing DR systems largely rely on human efforts in capturing DRs along design activities according to some predefined DR models. However, these systems require heavy human involvement and they do not have the capacity to extract DRs from design archival documents, which contain rich DR information but are usually unstructured or semistructured texts, e.g., design documents, service reports, and test reports. In view of such challenges, it has motivated us to propose a new DR model to intelligently discover DRs from design archival documents. In this paper, we propose an issue, solution and artifact layer (ISAL) model for DR representation and approaches for rationale information discovery from design archival documents. We also introduce a DR repository construction platform based on the ISAL model by integrating rationale information from both design archival documents and design processes. Using patent documents as our research data, we conduct a conceptual comparison and experimental study of DR discovery especially for artifact information extraction. Results demonstrate the merits of our proposal. Lastly, we discuss potential applications by taking advantage of our ISAL model.
Hybrid Association Mining and Refinement for Affective Mapping in Emotional Design
Authors: Zhou Feng , Jiao Jianxin Roger , Schaefer Dirk , Chen Songlin
Published: September 2010

Emotional design entails a bidirectional affective mapping process between affective needs in the customer domain and design elements in the designer domain. To leverage both affective and engineering concerns, this paper proposes a hybrid association mining and refinement (AMR) system to support affective mapping decisions. Rough set and K optimal rule discovery techniques are applied to identify hidden relations underlying forward affective mapping. A rule refinement measure is formulated in terms of affective quality. Ordinal logistic regression (OLR) is derived to model backward affective mapping. Based on conjoint analysis, a weighted OLR model is developed as a benchmark of the initial OLR model for backward refinement. A case study of truck cab interior design is presented to demonstrate the feasibility and potential of the hybrid AMR system for decision support to forward and backward affective mapping.
Analysis of Nonlinear Free Vibration of Circular Plates With Cut-Outs Using R-Function Method
Authors: Avramov K. V. , Tyshkovets O. , Maksymenko-Sheyko K. V.
Published: September 2010

Geometrically nonlinear vibrations of circular plate with two cut-outs are simulated by the von Karman equations with respect to displacements. The combination of the Rayleigh–Ritz method and the R-function method, which allows satisfying all boundary conditions, is applied to obtain the vibration modes of the plate. The nonlinear vibrations are expanded using these vibrations modes. The dynamical system with three degrees of freedom is derived by Galerkin method. The influence of cut-outs size on linear and nonlinear vibrations of the plate is analyzed. For different parameters of cut-outs, different internal resonances occur in the plate. The nonlinear vibrations of the system for different internal resonances are analyzed by multiple scale method.
Analytical and Experimental Characterization of Macro-Fiber Composite Actuated Thin Clamped-Free Unimorph Benders
Authors: Bilgen Onur , Erturk Alper , Inman Daniel J.
Published: September 2010

A type of piezoceramic composite actuator known as Macro-Fiber Composite (MFC) is used commonly for actuation in smart-material structures. In this paper, a linear distributed parameter electromechanical model is proposed to predict the structural response to MFC actuated clamped-free thin cantilevered beams. The structural frequency response behavior between the tip velocity of the cantilever beam and the actuation voltage of the piezoelectric material is investigated experimentally for cantilevered unimorph MFC actuated benders with aluminum, brass, and steel substrate materials with different thicknesses. Good correlation is observed between the model and the experimental observations.
Three Degrees of Freedom Active Control of Pneumatic Vibration Isolation Table by Pneumatic and Time Delay Control Technique
Authors: Shin Yun-Ho , Kim Kwang-Joon , Chang Pyung-Hoon , Han Dong Ki
Published: September 2010

Based on previous feasibility study on one degree of freedom (1DOF) pneumatic active control of pneumatic springs, this paper presents procedures and results of a more realistic 3DOF active control of a pneumatic vibration isolation table. The 3DOF motion of the pneumatic table, consisting of heaving, rolling, and pitching, is controlled directly by adjusting air pressure in four pneumatic cylinders in a dynamic manner with pneumatic valves, without any external actuator such as an electromagnet or voice coil. The time delay control, which is a software chosen in this study, together with the hardware, i.e., the pneumatic actuator, is shown to be very powerful in enhancing the performance of vibration isolation for ground excitation as well as in settling time reduction for payload excitation through simulations and measurements on the 3DOF motion control system. New key results found in the experimental approach are that the pneumatic actuator shows a dynamic behavior of a second-order system, instead of a first-order system, which has been used in existing literatures so far, and that just feed-forward control of the pneumatic actuator by the second-order model can compensate for the inherently slow response characteristics of the pneumatic actuator very successfully. Effectiveness of the proposed active pneumatic control technique in the multi-input and multi-output system is shown via singular value decomposition analysis on the transmissibility matrix. Promising future of the proposed control and performance analysis technique is further discussed based on the results in the case of payload excitations as well.
Using a Characteristic Force Approach to Determine the Eigensolutions of an Arbitrarily Supported Linear Structure Carrying Lumped Attachments
Authors: Cha Philip D. , Honda Masanori
Published: September 2010

In this paper a characteristic force approach is developed that can be used to determine the eigenvalues and mode shapes of any arbitrarily supported linear structure carrying various lumped attachments, including a lumped mass, rotary inertia, grounded translational or torsional spring, grounded translational or torsional viscous damper, and an undamped or damped oscillator with or without a rigid body degree of freedom. Using the proposed approach, each lumped element is first replaced by the load, either a force or moment, that it exerts on the linear structure, thus transforming the free vibration problem into a forced vibration one. By expressing the deflection of the linear structure in terms of these forces or moments and enforcing the compatibility conditions at each attachment points, the roots of the characteristic determinant of these loads can be graphically or numerically solved to find the eigenvalues of the combined system. Once the eigenvalues have been found, the corresponding mode shapes can be readily obtained. The proposed method is easy to code, systematic to apply, and can be easily modified to accommodate any arbitrarily supported one- or two-dimensional linear structure carrying various lumped attachments.
The Effect of Axisymmetric Nonflatness on the Oscillation Frequencies of a Rotating Disk
Authors: Khorasany Ramin M. H. , Hutton Stanley G.
Published: September 2010

This study examines the frequency characteristics of thin rotating disks subjected to axisymmetric nonflatness. The equations of motion used are based on Von Karman’s plate theory. First, the eigenfunctions of the stationary disk problem corresponding to the stress function and transverse displacement are found. These eigenfunctions produce an equation that can be used in Galerkin’s method. The initial nonflatness is assumed to be a linear combination of the eigenfunctions of the transverse displacement of the stationary disk problem. Since the initial nonflatness is assumed to be axisymmetric, only eigenfunctions with no nodal diameters are considered to approximate the initial runout. It is supposed that the disk bending deflection is small compared with disk thickness, so we can ignore the second-order terms in the governing equations corresponding to the transverse displacement and the stress function. After simplifying and discretizing the governing equations of motion, we can obtain a set of coupled equations of motion, which takes the effect of the initial axisymmetric runout into account. These equations are then used to study the effect of the initial runout on the frequency behavior of the stationary disk. It is found that the initial runout increases the frequencies of the oscillations of a stationary disk. In the next step, we study the effect of the initial nonflatness on the critical speed behavior of a spinning disk.