bluuebunny/crossref_metadata_2025 huggingface dataset:
The Measurement of Suburban Sprawl: An Evaluation
Authors: Jaret Charles , Ghadge Ravi , Reid Lesley Williams , Adelman Robert M.
Published: February 2009

We review and analyze how suburban sprawl has been conceptualized and measured in recent urban research. We find that indexes created to measure sprawl in metropolitan areas do so in three different ways. Some measures are based on residential population density, others specifically measure the extent of job or employment sprawl, and others consider sprawl a multidimensional land use phenomenon (and provide separate indexes for each dimension). Our analyses show that (1) most residential population density indexes reflect other dimensions of sprawl; (2) it is useful to think of metropolitan areas as positioned on two distinct dimensions of sprawl (i.e., centeredness and density–mixed land use); and (3) job sprawl and residential sprawl vary independently from each other. We provide recommendations regarding which sprawl measures are most appropriate for research applications.
Hot and Cold Markets
Authors: Novy‐Marx Robert
Published: February 2009

This article considers why housing market conditions, including the ratio of buyers to sellers, expected time‐to‐sale and transaction prices are sensitive to fundamentals. These high sensitivities result from feedback: market participants optimally respond to shocks in a manner that amplifies a shock's initial impact, which in turn elicits further reinforcing responses. For example, a positive demand shock brings more buyers into a market. This improves the bargaining position of sellers, who then sell more quickly, decreasing the stock of sellers in the market. This further increases the relative number of buyers to sellers, amplifying the initial shock.
Do State Cost Control Policies Reduce Medicaid Prescription Drug Spending?
Authors: Simon Kosali , Tennyson Sharon , Hudman Julie
Published: February 2009

Abstract

We present the first systematic analysis of state policies limiting prescription drug access under Medicaid during 1990–2004, documenting their impact on states’ Medicaid prescription spending growth. We see substantial variation in the number and type of policies used by states, but a clear upward trend in restrictions over time. Analysis of state level annual spending growth shows that these restrictions have in general helped contain Medicaid prescription drug costs and that some approaches, such as the use of preferred drug lists (PDLs) and tiered copayment systems, may have been more effective than others.
Influential Articles, Journals, and Institutions in Risk Management and Insurance
Authors: Chan Kam C. , Liano Kartono
Published: February 2009

Abstract

We use a threshold citation approach to measure the influence of articles, journals, and institutions in risk management and insurance research. The three frequently cited articles in risk management and insurance research are “Increasing Risk: I. A Definition” by Rothschild and Stiglitz (1970), “Precautionary Saving in the Small and in the Large” by Kimball (1990), and “Equilibrium in Competitive Insurance Markets: An Essay on the Economics of Imperfect Information” by Rothschild and Stiglitz (1990). Journal of Risk and Insurance, Econometrica, and Journal of Political Economy are the three influential journals in risk management and insurance research. Furthermore, the five influential institutions in risk management and insurance research are the University of Pennsylvania, Harvard University, the University of Rochester, the University of Michigan, and Massachusetts Institute of Technology.
Neurodevelopmental delay in the Cln3Δex7/8 mouse model for Batten disease
Authors: Osório N. S. , Sampaio‐Marques B. , Chan C.‐H. , Oliveira P. , Pearce D. A. , Sousa N. , Rodrigues F.
Published: February 2009

Juvenile neuronal ceroid lipofuscinosis (JNCL), also known as Batten disease, is a fatal inherited neurodegenerative disorder. The major clinical features of this disease are vision loss, seizures and progressive cognitive and motor decline starting in childhood. Mutations in CLN3 are known to cause the disease, allowing the generation of mouse models that are powerful tools for JNCL research. In this study, we applied behavioural phenotyping protocols to test for early behavioural alterations in Cln3Δex7/8 knock‐in mice, a genetic model that harbours the most common disease‐causing CLN3 mutation. We found delayed acquisition of developmental milestones, including negative geotaxis, grasping, wire suspension time and postural reflex in both homozygous and heterozygous Cln3Δex7/8 preweaning pups. To further investigate the consequences of this neurodevelopmental delay, we studied the behaviour of juvenile mice and found that homozygous and heterozygous Cln3Δex7/8 knock‐in mice also exhibit deficits in exploratory activity. Moreover, when analysing motor behaviour, we observed severe motor deficits in Cln3Δex7/8 homozygous mice, but only a mild impairment in motor co‐ordination and ambulatory gait in Cln3Δex7/8 heterozygous animals. This study reveals previously overlooked behaviour deficits in neonate and young adult Cln3Δex7/8 mice indicating neurodevelopmental delay as a putative novel component of JNCL.
Amygdala protein kinase C epsilon controls alcohol consumption
Authors: Lesscher H. M. B. , Wallace M. J. , Zeng L. , Wang V. , Deitchman J. K. , McMahon T. , Messing R. O. , Newton P. M.
Published: February 2009

Alcoholism is a progressive disorder that involves the amygdala. Mice lacking protein kinase C epsilon (PKCɛ) show reduced ethanol consumption, sensitivity and reward. We therefore investigated whether PKCɛ signaling in the amygdala is involved in ethanol consumption. Local knockdown of PKCɛ in the amygdala reduced ethanol consumption and preference in a limited‐access paradigm. Further, mice that are heterozygous for the PKCɛ allele consume less ethanol compared with wild‐type mice in this paradigm. These mice have a >50% reduction in the abundance of PKCɛ in the amygdala compared with wild‐type mice. We conclude that amygdala PKCɛ is important for ethanol consumption in mice.
Methylphenidate to adolescent rats drives enduring changes of accumbal Htr7 expression: implications for impulsive behavior and neuronal morphology
Authors: Leo D. , Adriani W. , Cavaliere C. , Cirillo G. , Marco E. M. , Romano E. , Di Porzio U. , Papa M. , Perrone‐Capano C. , Laviola G.
Published: February 2009

Methylphenidate (MPH) administration to adolescent rodents produces persistent region‐specific changes in brain reward circuits and alterations of reward‐based behavior. We show that these modifications include a marked increment of serotonin (5‐hydroxy‐tryptamine) receptor type 7 (Htr7) expression and synaptic contacts, mainly in thenucleus accumbens, and a reduction of basal behavioral impulsivity. We show that neural and behavioral consequences are functionally related: administration of a selective Htr7 antagonist fully counteracts the MPH‐reduced impulsive behavior and enhances impulsivity when administered alone in naive rats. Agonist‐induced activation of endogenous Htr7 significantly increases neurite length in striatal neuron primary cultures, thus suggesting plastic remodeling of neuronal morphology. The mixed Htr (1a/7) agonist, 8‐OH‐DPAT, reduces impulsive behavior in adolescent rats and in naive adults, whose impulsivity is enhanced by the Htr7 antagonist. In summary, behavioral pharmacology experiments show that Htr7 mediates self‐control behavior, and brain primary cultures experiments indicate that this receptor may be involved in the underlying neural plasticity, through changes in neuronal cytoarchitecture.
Neuroligin‐3‐deficient mice: model of a monogenic heritable form of autism with an olfactory deficit
Authors: Radyushkin K. , Hammerschmidt K. , Boretius S. , Varoqueaux F. , El‐Kordi A. , Ronnenberg A. , Winter D. , Frahm J. , Fischer J. , Brose N. , Ehrenreich H.
Published: February 2009

Autism spectrum disorder (ASD) is a frequent neurodevelopmental disorder characterized by variable clinical severity. Core symptoms are qualitatively impaired communication and social behavior, highly restricted interests and repetitive behaviors. Although recent work on genetic mutations in ASD has shed light on the pathophysiology of the disease, classifying it essentially as a synaptopathy, no treatments are available to date. To develop and test novel ASD treatment approaches, validated and informative animal models are required. Of particular interest, in this context are loss‐of‐function mutations in the postsynaptic cell adhesion protein neuroligin‐4 and point mutations in its homologue neuroligin‐3 (NL‐3) that were found to cause certain forms of monogenic heritable ASD in humans. Here, we show that NL‐3‐deficient mice display a behavioral phenotype reminiscent of the lead symptoms of ASD: reduced ultrasound vocalization and a lack of social novelty preference. The latter may be related to an olfactory deficiency observed in the NL‐3 mutants. Interestingly, such olfactory phenotype is also present in a subgroup of human ASD patients. Tests for learning and memory showed no gross abnormalities in NL‐3 mutants. Also, no alterations were found in time spent in social interaction, prepulse inhibition, seizure propensity and sucrose preference. As often seen in adult ASD patients, total brain volume of NL‐3 mutant mice was slightly reduced as assessed by magnetic resonance imaging (MRI). Our findings show that the NL‐3 knockout mouse represents a useful animal model for understanding pathophysiological events in monogenic heritable ASD and for developing novel treatment strategies in this devastating human disorder.
Acute and chronic alcohol dose: population differences in behavior and neurochemistry of zebrafish
Authors: Gerlai R. , Chatterjee D. , Pereira T. , Sawashima T. , Krishnannair R.
Published: February 2009

The zebrafish has been in the forefront of developmental genetics for decades and has also been gaining attention in neurobehavioral genetics. It has been proposed to model alcohol‐induced changes in human brain function and behavior. Here, adult zebrafish populations, AB and SF (short‐fin wild type), were exposed to chronic treatment (several days in 0.00% or 0.50% alcohol v/v) and a subsequent acute treatment (1 h in 0.00%, 0.25%, 0.50% or 1.00% alcohol). Behavioral responses of zebrafish to computer‐animated images, including a zebrafish shoal and a predator, were quantified using videotracking. Neurochemical changes in the dopaminergic and serotoninergic systems in the brain of the fish were measured using high‐precision liquid chromatography with electrochemical detection. The results showed genetic differences in numerous aspects of alcohol‐induced changes, including, for the first time, the behavioral effects of withdrawal from alcohol and neurochemical responses to alcohol. For example, withdrawal from alcohol abolished shoaling and increased dopamine and 3,4‐dihydroxyphenylacetic acid in AB but not in SF fish. The findings show that, first, acute and chronic alcohol induced changes are quantifiable with automated behavioral paradigms; second, robust neurochemical changes are also detectable; and third, genetic factors influence both alcohol‐induced behavioral and neurotransmitter level changes. Although the causal relationship underlying the alcohol‐induced changes in behavior and neurochemistry is speculative at this point, the results suggest that zebrafish will be a useful tool for the analysis of the biological mechanisms of alcohol‐induced functional changes in the adult brain.
Primate home range andGRIN2A, a receptor gene involved in neuronal plasticity: implications for the evolution of spatial memory
Authors: Ali F. , Meier R.
Published: February 2009

N‐methyl‐d‐aspartate (NMDA) glutamate receptors play crucial roles in neuronal synaptic plasticity, learning and memory. However, as to whether different NMDA subunits are implicated in specific forms of memory is unclear. Moreover, nothing is known about the interspecific genetic variability of theGRIN2Asubunit and how this variation can potentially explain evolutionary changes in behavioral phenotypes. Here, we used 28 primateGRIN2Asequences and various proxies of memory across primates to investigate the role ofGRIN2A. Codon‐specific sequence analysis on these sequences showed thatGRIN2Ain primates coevolved with a likely ecological proxy of spatial memory (relative home‐range size) but not with other indices of non‐spatial learning and memory such as social memory and social learning. Models based on gene averages failed to detect positive selection in primate branches with major changes in relative home‐range size. This implies that accelerated evolution is concentrated in specific parts of the protein expressed byGRIN2A. Overall, our molecular evolution study, the first onGRIN2A, supports the notion that different NMDA subunits may play a role in specific forms of memory and that phenotypic diversity along with genetic evolution can be used to investigate the link between genes and behavior across evolutionary time.
Diversity in commercial varieties and landraces of black eggplants and implications for broadening the breeders’ gene pool
Authors: Muñoz‐Falcón J.E. , Prohens J. , Vilanova S. , Nuez F.
Published: February 2009

Black‐coloured eggplants (Solanum melongena) represent the commercially most important group of eggplants in Europe and North America. Most of the modern varieties of black eggplants correspond to F1 hybrids, which at the same time constitute an elite gene pool for the development of new varieties. However, there are many black landraces and old varieties, which could be useful as sources of variation for black eggplant breeding programmes as well as for the broadening of the genetic diversity of the breeders’ gene pool. We have studied the morphological and molecular [amplified fragment length polymorphism and simple sequence repeat (SSR)] diversity in a collection of 38 black eggplant accessions, including commercial (modern F1 hybrid and old nonhybrid) varieties and landraces as well as in six nonblack control eggplants, from different origins. The results show that black eggplants contain a considerable morphological and molecular diversity, but commercial varieties, and in particular F1 hybrids, display a reduced morphological and molecular diversity when compared with landraces. The principal components analysis morphological and principal coordinates analysis molecular analyses show that commercial F1 hybrids group together, indicating that they share a common and narrow gene pool. Commercial F1 hybrids present a series of productive advantages, like early production, intense black colour (low L*, a* and b*) values and absence of fruit calyx prickles. However, several of the landraces and old nonhybrid varieties studied present a high yield as well as other traits of interest for eggplant breeding. Furthermore, given the low genetic diversity of F1 hybrids and the moderate level of SSR heterozygosity found in these materials (0.382), introduction of black landraces and old varieties in the present breeding programmes could contribute to broadening the gene pool used by breeders and this could help increase the heterosis for yield of F1 hybrids, which is greatly favoured by high heterozygosity levels.
Dietary fatty acids and inflammation
Authors: CLIFTON Peter
Published: February 2009

Introduction:  It is commonly believed that inflammation can be reduced by lowering the dietary ratio of n‐6 (linoleic acid) to n‐3 polyunsaturated fatty acids as a means of lowering arachidonic acid levels in cell membranes. This review will examine this proposition.

Results:  Although many pro‐inflammatory molecules can be produced from arachidonic acid and this long‐chain n‐6 fatty acid can be produced from linoleic acid, changing dietary linoleic acid intake over a wide range does not have any significant effect on arachidonic acid levels in cell membranes, inflammation or immune functions. There are no data that show lowering dietary n‐6 polyunsaturated fats reduces inflammation. In contrast, arachidonic acid levels in cell membranes and inflammatory parameters are lowered by increasing intakes of long‐chain n‐3 polyunsaturated fatty acids. Resolvins and protectins, both derivatives of long‐chain n‐3 fats, also have potential anti‐inflammatory activity. In high doses, long‐chain n‐3 fats may have modest, beneficial effects on inflammation in rheumatoid arthritis. However, many studies have shown no effects of fish oil on inflammation parameters.

Conclusions:  The dietary n‐6/n‐3 ratio is not a useful measure of the inflammatory nature of a diet, though the absolute amount of dietary long‐chain n‐3 polyunsaturated fatty acids may be a guide.
Developmental outcomes in early compared with delayed surgery for glue ear up to age 7 years: a randomised controlled trial
Authors: Hall A.J. , Maw A.R. , Steer C.D.
Published: February 2009

Objectives:  To investigate whether early versus delayed surgery for children severely affected by otitis media with effusion (OME) results in improved performance on developmental tests up to age 7 years.

Design:  Follow‐up of a randomised controlled trial.

Setting:  University of Bristol.

Participants:  One hundred and eighty‐two children (mean age 35 months) with persistent OME, hearing loss and speech, language or behaviour problems who were originally eligible and randomised to either early surgery or delayed surgery after a period of watchful waiting were followed‐up as part of the Avon Longitudinal Study of Parents and Children (ALSPAC) at age 4½ and 7–8 years.

Main outcome measures:  Measures included behaviour, language, educational attainment tests, hearing, reading, cognition and coordination.

Results:  Of the original randomised trial, 88 of 92 of the early surgery and 74 of 90 of the watchful waiting group were still participating in ALSPAC. Analysis was by intention to treat. At age 4 ½ years there were significant differences in teacher assessment of language (adj OR 3.45, 95% CI: 1.42–8.39) and writing (adj OR 3.74, 95% CI: 1.51–9.27), in favour of early surgery. At age 7–8 years, there was a significant difference on teacher report of emotional problems (adj OR 4.11, 95% CI: 1.15–14.64) in favour of early surgery. There were no other significant differences.

Conclusions:  Early surgery for the child severely affected by OME may be associated with subtle benefits at age 4½ years. This may continue to 7–8 years but the small study size makes it difficult to distinguish these effects from chance. A larger study is recommended.
Bidimensional measurement of nasopharyngeal carcinoma: a simple method to predict outcomes
Authors: Lee C.‐C. , Ho H.‐C. , Su Y.‐C. , Lee M.‐S. , Hsiao S.‐H. , Hwang J.‐H. , Hung S.‐K , Chou P. , Lee C.‐C.
Published: February 2009

Objectives:  To determine whether the standard techniques of measuring tumour size could be applied to the measurement of nasopharyngeal carcinoma.

Study design:  A retrospective review of case notes from the Buddhist Tzu Chi Dalin General Hospital archives was performed.

Settings:  The Buddhist Tzu Chi Dalin General Hospital is a teaching hospital in Taiwan.

Participants:  All patients with nasopharyngeal carcinoma were included.

Main outcome measures:  Ninety‐eight patients with newly diagnosed nasopharyngeal carcinoma were treated with high‐dose radiotherapy and chemotherapy were enrolled in this study. Computed tomography‐derived primary tumour volume, bidimensional measurement and unidimensional measurement were recorded. Intrarater reliability was measured. To examine the validity of various measurements, we estimated the Spearman’s correlation co‐efficients between those measurements and the gold standard value (primary tumour volume measurement with summation of area techniques). Univariate and multivariate analyses were performed and Kaplan–Meier survival curves constructed.

Results:  There was a significant association between primary tumour volume and bidimensional measurement with respect to tumour size at diagnosis (Spearman’s correlation co‐efficient = 0.845, P < 0.001). Using age, gender, chemotherapy status and T‐stage as covariate, bidimensional measurement remained an independent prognostic factor for any relapse [Hazard ratio = (HR) 1.066; P = 0.029], and overall survival (HR = 1.097; P = 0.007). Patients with small bidimensional measurement (<10 cm2) had better prognosis and fewer recurrences.

Conclusions:  When using simple measurement to evaluate nasopharyngeal carcinoma, the bidimensional measurement may be used to measure size at diagnosis. Patients with small bidimensional measurement had better prognosis and fewer recurrences. Bidimensional measurement may be further considered to improve the current staging system.
Reduced Activity of CD13/Aminopeptidase N (APN) in Aggressive Meningiomas Is Associated with Increased Levels of SPARC
Authors: Mawrin Christian , Wolke Carmen , Haase Daniela , Krüger Sabine , Firsching Raimund , Keilhoff Gerburg , Paulus Werner , Gutmann David H. , Lal Anita , Lendeckel Uwe
Published: February 2009

Meningiomas are the second most common brain tumors in adults, and meningiomas exhibit a tendency to invade adjacent structures. Compared with high‐grade gliomas, little is known about the molecular changes that potentially underlie the invasive behavior of meningiomas. In this study, we examined the expression and function of the membrane alanyl‐aminopeptidase [mAAP, aminopeptidase N (APN), CD13, EC3.4.11.2] zinc‐dependent ectopeptidase in meningiomas and meningioma cell lines, based on its prior association with tumor invasion in colorectal and renal carcinomas. We found a significant reduction of APNmRNA and protein expression, as well as enzymatic activity, in high‐grade meningiomas. While meningioma tumor cell proliferation was not affected by either pharmacologic APN inhibition or siRNA‐mediated APN silencing, APN pharmacologic and siRNA knockdown significantly reduced meningioma cell invasion in vitro. Next, we employed pathway‐specific cDNA microarray analyses to identify extracellular matrix and adhesion molecules regulated by APN, and found that APN‐siRNA knockdown substantially increased the expression of secreted protein, acidic and rich in cysteine (SPARC)/osteonectin. Finally, we demonstrated that SPARC, which has been previously associated with meningioma invasiveness, was increased in aggressive meningiomas. Collectively, these results suggest that APN expression and enzymatic function is reduced in aggressive meningiomas, and that alterations in the balance between APN and SPARC might favor meningioma invasion.
Estimating species diversity in a guild of Neotropical skippers (Lepidoptera: Hesperiidae) with artificial lures is a sampling problem
Authors: DEVRIES PHILIP J. , AUSTIN GEORGE T. , MARTIN NOLAND H.
Published: February 2009

Abstract.

Butterflies are frequently used to investigate Neotropical diversity, but the family Hesperiidae is almost never employed as a focal group. Sampling Hesperiidae with artificial lures has been used to assist in species richness estimates of males that use bird droppings as a resource, but its effectiveness for estimating total hesperiid site diversity is unknown.

This study characterises species richness and abundance in a diverse assemblage of Hesperiidae sampled at artificial lures. Sampled and estimated richness among taxonomic subsets were compared to the known site richness. These comparisons are used to assess artificial lures as a method for sampling total richness of Hesperiidae. We tested for potential differences in attraction in lures placed with and without the presence of army ant swarms.

Five years of intermittent sampling with lures recovered 65% of the known Hesperiidae species richness at the study site. We found the subfamilies were differentially attracted to lures, where 86% of Eudaminae, 56% of Hesperiinae and 55% of Pyrginae species known from the site were recovered by lures. Species accumulation and taxonomic diversity differed among lures placed alone, and those placed in the presence of army ants.

Our results suggest that sampling with artificial lures can be used to estimate diversity of Neotropical Eudaminae and a few tribes of Hesperiinae at some sites. Available evidence indicates that Hesperiidae feeding at bird droppings is predominately a Neotropical phenomenon. Finally, we conclude that estimating diversity in Neotropical Hesperiidae will require long‐term studies that use multiple sampling techniques.
New Fossil Palaeontinids from the Middle Jurassic of Daohugou, Inner Mongolia, China (Insecta, Hemiptera)
Authors: WANG Ying , REN Dong
Published: February 2009

Two new genera and species of fossil Palaeontinidae are described from Daohugou Village, Inner Mongolia, China: Cladocossus undulatus gen. et sp. nov. and Cricocossus paradoxus gen. et sp. nov. Both new genera are described based on well‐preserved forewings. This discovery confirms the high diversity of palaeontinids during the Middle Jurassic. Both specimens have interesting modal structures which are new to Palaeontinidae: M five‐branched and M3 with two branches. Based on this character, wing structural characteristic is discussed.
Evolution of Dentary Diastema in Iguanodontian Dinosaurs
Authors: KUBOTA Katsuhiro , KOBAYASHI Yoshitsugu
Published: February 2009

The dentary diastema of iguanodontians has been considered to be related to its unique jaw mechanism for herbivorous adaptation. The dentary and diastema lengths of iguanodontians were measured and compared to elucidate the evolution of iguanodontian diastema. A gap in ratios between most non‐hadrosaurid iguanodontians and hadrosaurids was observed, suggesting that all non‐hadrosaurid iguanodontians, expect forOuranosaurus nigeriensisandProtohadros byrdi, lack a diastema or have a short diastema, although some other taxa have been considered to have a long diastema in previous studies. In non‐hadrosaurid iguanodontians, some large‐sized forms, such asIguanodon bernissartensis, Shuangmiaosaurus gilmorei, and possiblyEolambia caroljonesa, had a short diastema through ontogeny, whereasOuranosaurus nigeriensisandProtohadros byrdideveloped a long diastema convergently. The development of a long diastema of hadrosaurine hadrosaurids may be different from that of lambeosaurine hadrosaurids. Some hadrosaurunes (Edmontosaurus annectens, Edmontosaurus regalis, andSaurolophus angustirostris) may have developed a long diastema in the subadult stage and showed little elongation of dentary diastema through ontogeny. Lambeosaurines (Corythosaurus casuariusandLambeosaurus lambei) tend to have a short diastema in the embryonic and subadult stages, and an elongated diastema from the subadult to adult stages.
Variations of Microbial Communities and the Contents and Isotopic Compositions of Total Organic Carbon and Total Nitrogen in Soil Samples during Their Preservation
Authors: TAO Qianye , LI Yumei , WANG Guo'an , QIAO Yuhui , LIU Tung‐Sheng
Published: February 2009

Semi‐sealed preservation of soil samples at different moisture of 4% and 23%, respectively, was simulated to observe the variations of soil microbial communities and determine the contents and isotopic compositions of the total organic carbon and total nitrogen on the 7th and 30th day, respectively. The results show that during preservation, the quantity of microbial communities tended to increase first and then decrease, with a wider variation range at higher moisture (23%). At the moisture content of 23%, the microbial communities became more active on the 7th day, but less after 30 days, and their activity was stable with little fluctuation at the moisture content of 4%. However, there were no significant changes in the contents and isotopic compositions of the total organic carbon and total nitrogen. During preservation, the responses of soil microbes to the environment are more sensitive to changes in the total nitrogen and organic carbon contents. It is thus suggested that the variations of microbial communities have not exerted remarkable impacts on the isotope compositions of the total nitrogen and total organic carbon.
Acantholimondoganii sp. nov. (Plumbaginaceae) with persistent circinnate leaf bases, from Turkey
Authors: Bağcı Yavuz , Doğu Süleyman , Akaydın Galip
Published: February 2009

The new species Acantholimon doganii Y. Bağcı, Doğu & Akaydın is described and illustrated. Diagnostic morphological characteristics in closely related species are discussed and the conservation status of the new species is analysed. A revised key to the Turkish Acantholimon species with persistent circinnate leaf basis is also provided.
Self‐ligating brackets in orthodontics: do they deliver what they claim?
Authors: Miles PG
Published: February 2009

Self‐ligating brackets have enjoyed recent popularity in the orthodontic marketplace with various claims made including faster ligation, lower friction, faster treatment, less pain, waking up the tongue, and fewer appointments. Although various designs of self‐ligating brackets have been available for many years they have only recently surged in popularity on the back of these claims but what evidence is there to support these claims? This review article examines the current available evidence regarding treatment duration, influence on archform, and the speed of tying and untying self‐ligating brackets compared with conventional brackets and methods of ligation.
The effect of periodontal therapy on serum TNF‐α and HbA1c levels in type 2 diabetic patients
Authors: Dağ A , Fırat ET , Arıkan Ş , Kadiroğlu AK , Kaplan A
Published: February 2009

Background:  To determine the effect of non‐surgical periodontal therapy on serum TNF‐α and HbA1c levels in poorly and well‐controlled type 2 diabetic patients.

Methods:  In total, 45 patients were enrolled in the study; 30 patients with type 2 diabetes mellitus with periodontitis (15 with poorly controlled diabetes, HbA1c ≥ 7%, group 1A and 15 with well‐controlled diabetes, HbA1c < 7%, group 1B) and 15 patients that were systemically healthy with periodontitis (group 2). The plaque index, gingival index, probing depth, clinical attachment loss, gingival bleeding index, HbA1c value, and circulating TNF‐α concentration were measured at baseline and three months after the non‐surgical periodontal therapy.

Results:  All periodontal parameters and serum TNF‐α levels were significantly decreased three months after the non‐surgical periodontal therapy compared to the baseline values in all groups. The HbA1c values were significantly decreased only in well‐controlled diabetic patients. We found no significant differences in the periodontal parameters or TNF‐α levels at baseline and after three months between the two groups.

Conclusions:  Although non‐surgical periodontal therapy eliminates local/systemic infection and inflammation via decreases in TNF‐α, it is insufficient for significantly reducing HbA1c levels without strict glycaemic control in poorly controlled diabetic patients in a short time period.
Load transfer characteristics of unilateral distal extension removable partial dentures with polyacetal resin supporting components
Authors: Jiao T , Chang T , Caputo AA
Published: February 2009

Background:  To photoelastically examine load transfer by unilateral distal extension removable partial dentures with supporting and retentive components made of the lower stiffness polyacetal resins.

Methods:  A mandibular photoelastic model, with edentulous space distal to the right second premolar and missing the left first molar, was constructed to determine the load transmission characteristics of a unilateral distal extension base removable partial denture. Individual simulants were used for tooth structure, periodontal ligament, and alveolar bone. Three designs were fabricated: a major connector and clasps made from polyacetal resin, a metal framework as the major connector with polyacetal resin clasp and denture base, and a traditional metal framework I‐bar removable partial denture. Simulated posterior bilateral and unilateral occlusal loads were applied to the removable partial dentures.

Results:  Under bilateral and left side unilateral loading, the highest stress was observed adjacent to the left side posterior teeth with the polyacetal removable partial denture. The lowest stress was seen with the traditional metal framework. Unilateral loads on the right edentulous region produced similar distributed stress under the denture base with all three designs but a somewhat higher intensity with the polyacetal framework.

Conclusions:  The polyacetal resin removable partial denture concentrated the highest stresses to the abutment and the bone. The traditional metal framework I‐bar removable partial denture most equitably distributed force. The hybrid design that combined a metal framework and polyacetal clasp and denture base may be a viable alternative when aesthetics are of primary concern.
Influence of changing the chewing region on mandibular movement
Authors: Hashii K , Tomida M , Yamashita S
Published: February 2009

Background:  In the shortened dental arch condition, little is known of how patients adapt their jaw function during mastication to the new oral environment. This study aimed to investigate the changes in mandibular movements when the chewing region was changed from the first molar to the first premolar.

Methods:  Thirty clinical residents with natural dentitions were recruited. The subjects were asked to chew a piece of beef jerky using either the first molar or the first premolar on the preferred chewing side. Three‐dimensional trajectories of lower incisors and both condyles were analysed using a jaw movement tracking device with six degrees of freedom during the period between the onset and offset of electromyographic bursts from the masseter and anterior temporal muscles.

Results:  The closing angle of the lower incisors for first premolar chewing was narrower in comparison with that for first molar chewing (p < 0.05). The lengths of the condylar trajectories and the maximum velocities of the condylar movement for first premolar chewing were smaller and slower, respectively, in comparison with those for first molar chewing (both sides; p < 0.01).

Conclusions:  The mandibular movement during mastication might be changed to adapt the premolar chewing because of a loss of posterior occlusal supports.
Life‐threatening complications associated with acute monocytic leukaemia after dental treatment
Authors: Koulocheris P , Metzger MC , Kesting MR , Hohlweg‐Majert B
Published: February 2009

It is highly recommended to conduct a prophylactic check for any dental problems on patients who suffer from leukaemia before chemotherapy begins. Bacteraemia caused by oral microflora may be very dangerous for patients with haematological malignancies. However, it should be noted that the prophylactic process itself might bring about life‐threatening complications if there is only a short interval between dental treatment and the beginning of chemotherapy, or if the dental treatment is too aggressive. We present a case where this prophylactic procedure produced life‐threatening complications for a patient with acute myeloid leukaemia.
Static bone cavity in the condylar neck and mandibular notch of the mandible
Authors: Minowa K , Kobayashi I , Matsuda A , Ohmori K , Kurokawa Y , Inoue N , Totsuka Y , Nakamura M
Published: February 2009

This study presents the radiographic findings of two cases of static bone cavity in the inferior aspect of the condylar neck and mandibular notch of the mandible. On plain CT, a soft tissue mass was observed in each cavity. The submandibular gland and the other glands were not found in each cavity. On contrast‐enhanced CT, the soft tissue in the cavity in the inferior aspect of the condylar neck had marked linear enhancement and dilated vasculature structure was observed in the cavity. On the contrast‐enhanced MRI, the soft tissue in the cavity of the mandibular notch had marked enhancement and flow void was detected in the cavity. In the inferior aspect of the condylar neck, the cavity size had enlarged radiographically over a period of three years. Vascular lesions were found in the cavity located in the inferior aspect of the condylar neck and mandibular notch of the mandible by both CT and MRI. The vascular lesion might explain the enlargement of the static bone cavity.
An unusual healing of a replanted permanent lateral incisor
Authors: Arrow P
Published: February 2009

Background:  Continued development and healing of an immature permanent tooth root was reported to have occurred. The continued viability of Hertwig’s root sheath was thought to be necessary and responsible. Continued development of a tooth root separate from the body of the tooth was reported, but the initiation and development associated with a replanted tooth was not observed.

Methods:  A 9‐year‐old boy sustained an avulsion injury to his upper right lateral incisor. The tooth was replanted within 5–10 minutes of the incident and was splinted approximately 30 minutes after the injury, and then monitored for 2.25 years.

Results:  The periodontal tissues healed well. Root development was arrested with calcific deposit evident in the pulp canal. A radio‐opaque structure, apical to the tooth root, was seen to develop on the radiograph 11 weeks after the initial trauma. The opaque mass continued to develop over the next two years of observation.

Conclusions:  Immature permanent tooth roots show remarkable reparative powers. Clinicians need to be vigilant and close continued monitoring of traumatized immature teeth is recommended.
Primes with an average sum of digits
Authors: Drmota Michael , Mauduit Christian , Rivat Joël
Published: February 2009

The main goal of this paper is to provide asymptotic expansions for the numbers#{p≤x:p prime,sq(p)=k} forkclose to ((q−1)/2)logqx, wheresq(n) denotes theq-ary sum-of-digits function. The proof is based on a thorough analysis of exponential sums of the form$\sum _{p\le x} e(\alpha s_q(p))$(where the sum is restricted topprime), for which we have to extend a recent result by the second two authors.
Vibration Analysis of a Circular Tunnel With Jointed Liners Embedded in an Elastic Medium Subjected to Seismic Waves
Authors: Jeng Dong-Sheng , Lu Jian-Fei
Published: February 2009

This paper presents a frequency domain analysis of a circular tunnel with piecewise liners subjected to seismic waves. In our model, the surrounding medium of the tunnel is considered as a linear elastic medium and described by the dynamic elasticity theory, while piecewise liners and connecting joints are treated as curved beams and described by a curved beam theory. Scattered wave field in the surrounding elastic medium are obtained by the wave function expansion approach. The governing equations for vibrations of a curved beam are discretized by the general differential quadrature method. We use domain decomposition methods to establish the global discrete dynamic equations for piecewise liners. Boundary least squares collocation methods, based on the continuity conditions of stresses and displacements between surrounding soil and the piecewise liners, are used to determine the response of the liners and the surrounding medium. Numerical results conclude that the presence of the joints significantly changes the distributions of the tunnel internal force, and dramatically increase shear forces and moment of the tunnel liners around joints.
Impact of Manufacturing Variability on Combustor Liner Durability
Authors: Bradshaw Sean , Waitz Ian
Published: February 2009

This paper presents a probability-based systems-level approach for assessing the impact of manufacturing variability on combustor liner durability. Simplified models are used to link combustor life, liner temperature variability, and the effects of manufacturing variability. A probabilistic analysis is then applied to the simplified models to estimate the combustor life distribution. The typical combustor life was found to be approximately 20% less than the estimate life using deterministic methods for these combustors, and the probability that a randomly selected combustor will fail earlier than expected using deterministic methods is approximately 80%. The application of a sensitivity analysis to a surrogate model for the life identified the leading drivers of the minimum combustor life and the typical combustor life as the material property variability and the circumferential variability of turbulent mixing rates, respectively.
Combustion Performance of Biodiesel and Diesel-Vegetable Oil Blends in a Simulated Gas Turbine Burner
Authors: Panchasara Heena V. , Simmons Benjamin M. , Agrawal Ajay K. , Spear Scott K. , Daly Daniel T.
Published: February 2009

Recent increases in fuel costs, concerns for global warming, and limited supplies of fossil fuels have prompted wide spread research on renewable liquid biofuels produced domestically from agricultural feedstock. In this study, two types of biodiesels and vegetable oil (VO) are investigated as potential fuels for gas turbines to generate power. Biodiesels produced from VO and animal fat were considered in this study. The problems of high viscosity and poor volatility of VO (soybean oil) were addressed by using diesel-VO blends with up to 30% VO by volume. Gas chromatography/mass spectrometry, thermogravimetric analysis, and density, kinematic viscosity, surface tension, and water content measurements were used to characterize the fuel properties. The combustion performance of different fuels was compared experimentally in an atmospheric pressure burner with an air-assist injector and swirling primary air around it. For different fuels, the effect of the atomizing airflow rate on Sauter mean diameter was determined from a correlation for air-assist atomizers. Profiles of nitric oxides (NOx) and carbon monoxide (CO) emissions were obtained for different atomizing airflow rates, while the total airflow rate was kept constant. The results show that despite the compositional differences, the physical properties and emissions of the two biodiesel fuels are similar. Diesel-VO fuel blends resulted in slightly higher CO emissions compared with diesel, while the NOx emissions correlated well with the flame temperature. The results show that the CO and NOx emissions are determined mainly by fuel atomization and fuel/air mixing processes, and that the fuel composition effects are of secondary importance for fuels and operating conditions of the present study.
Spatiotemporal Characterization of a Conical Swirler Flow Field Under Strong Forcing
Authors: Lacarelle A. , Faustmann T. , Greenblatt D. , Paschereit C. O. , Lehmann O. , Luchtenburg D. M. , Noack B. R.
Published: February 2009

In this study, a spatiotemporal characterization of forced and unforced flows of a conical swirler is performed based on particle image velocimetry (PIV) and laser Doppler anemometry (LDA). The measurements are performed at a Reynolds number of 33,000 and a swirl number of 0.71. Axisymmetric forcing is applied to approximate the effects of thermoacoustic instabilities on the flow field at the burner inlet and outlet. The actuation frequencies are set at the natural flow frequency (Strouhal number Stf≈0.92) and two higher frequencies (Stf≈1.3 and 1.55) that are not harmonically related to the natural frequency. Phase-averaged measurement are used as a first step to visualize the coherent flow structures. Second, proper orthogonal decomposition (POD) is applied to the PIV data to characterize the effect of the actuation on the fluctuating flow. Measurements indicate a typical natural flow instability of helical nature in the unforced case. The associated induced pressure and flow oscillations travel upstream to the swirler inlet where generally fuel is injected. This observation is of critical importance with respect to the stability of the combustion. Harmonic actuation at different frequencies and amplitudes does not affect the mean velocity profile at the outlet, while the coherent velocity fluctuations are strongly influenced at both the inlet and outlet. On one hand, the dominant helical mode is replaced by an axisymmetric vortex ring if the flow is forced at the natural flow frequency. On the other hand, the natural flow frequency prevails at the outlet under forcing at higher frequencies and POD analysis indicates that the helical structure is still present. The presented results give new insight into the flow dynamics of a swirling flow burner under strong forcing.
Steady-State and Transient Performance Modeling of Smart UAV Propulsion System Using SIMULINK
Authors: Ki Jayoung , Kong Changduk , Kho Seonghee , Lee Changho
Published: February 2009

Because an aircraft gas turbine operates under various flight conditions that change with altitude, flight velocity, and ambient temperature, the performance estimation that considers the flight conditions must be known before developing or operating the gas turbine. More so, for the unmanned aerial vehicle (UAV) where the engine is activated by an onboard engine controller in emergencies, the precise performance model including the estimated steady-state and transient performance data should be provided to the engine control system and the engine health monitoring system. In this study, a graphic user interface (GUI) type steady-state and transient performance simulation model of the PW206C turboshaft engine that was adopted for use in the Smart UAV was developed using SIMULINK for the performance analysis. For the simulation model, first the component maps including the compressor, gas generator turbine, and power turbine were inversely generated from the manufacturer’s limited performance deck data by the hybrid method. For the work and mass flow matching between components of the steady-state simulation, the state-flow library of SIMULINK was applied. The proposed steady-state performance model can simulate off-design point performance at various flight conditions and part loads, and in order to evaluate the steady-state performance model their simulation results were compared with the manufacturer’s performance deck data. According to comparison results, it was confirmed that the steady-state model agreed well with the deck data within 3% in all flight envelopes. In the transient performance simulation model, the continuity of mass flow (CMF) method was used, and the rotational speed change was calculated by integrating the excess torque due to the transient fuel flow change using the Runge–Kutta method. In this transient performance simulation, the turbine overshoot was predicted.
Creep Degradation of Thermally Exposed IN738C Superalloy
Authors: Aghaie-Khafri M. , Farahany S.
Published: February 2009

Creep degradation of an IN738C superalloy after long-term thermal exposure in an atmospheric furnace was investigated by means of accelerated creep tests. Experimental observation showed that the minimum creep rate increased by increasing the exposure time or exposure temperature and is a key factor for predicting creep life during long time, high temperature service. Concerning the exposure temperature and time, an empirical equation has been presented to estimate the creep lives of the pre-exposed specimens. Furthermore, the accuracy of the Monkman–Grant (Proceedings of ASTM, Vol. 56, pp. 593–620) relationship has been verified by experimental results.