bluuebunny/crossref_metadata_2025 huggingface dataset:
Guest Editorial on the Festschrift “Challenges in population oral health for the 21st Century”
Authors: McGrath Colman , Lawrence Herenia P. , Blinkhorn Anthony
Published: September 2012

This Festschrift provides important and valuable guidance on population oral health. It is unfortunate that it coincides with the retirement of one of population oral health's pioneers, Professor John (AJ) Spencer, who has made significant contributions to the subject over the last 35 years. Oral diseases and disorders remain prevalent and have detrimental effects on individuals, and society‐at‐large. Many of our attempts to improve population oral health through existing oral health services have met with limited success, owing to the focus on ‘care’ rather than ‘cure’. It has long been recognised that oral diseases are largely behavioural in origin; but this approach at the individual level has not been entirely successful. There is a need to consider ‘mid‐ and up‐stream’ approaches to changing oral health and health care delivery systems. However social inequalities are a major determinant of oral health, and their influence in oral health are omnipresent, which emphasises the important role of population oral health in future health care strategies. The Festschrift provides theoretical and empirical evidence of the need for further epidemiological investigations (particularly life course studies), innovative approaches to oral health surveillance and oral health outcome evaluation, plus a realisation that multidisciplinary approaches are the way forward. In an information and globalization era, we must put the ‘population’ into oral health and this is our challenge for the 21st Century.
Inferring behavioural mechanisms in habitat selection studies getting the null‐hypothesis right for functional and familiarity responses
Authors: Van Moorter Bram , Visscher Darcy , Herfindal Ivar , Basille Mathieu , Mysterud Atle
Published: September 2012

Recent studies of animal habitat selection are inferring more detail regarding the behavioural mechanisms involved, like functional responses and familiarity effects. Changes in animals’ use or selection of a habitat type with changing availability are commonly interpreted as a functional response in habitat preference. Studies of familiarity inferred preference for familiar locations from selection for previously visited locations after accounting for habitat‐related preference. We simulated movement paths on discrete landscapes using random walk models with known habitat selection behaviour to assess emergent properties related to habitat selection in the context of functional and familiarity responses. The behavioural interpretation of functional responses relies on the relationship between habitat use and preference. Unfortunately, this relationship is not unique and depends upon the habitat choice mechanism: habitat use can be proportional to preference or proportional to availability (called respectively, hierarchical and simultaneous choice). We found that when the analytical method did not match the choice mechanism, strong functional responses were observed in habitat selection, even though habitat preference was kept constant. Therefore, functional responses need to be discussed in the context of an animal's habitat choice mechanism. In the absence of familiarity‐related preference, we found no familiarity effect while accounting for all habitat variables. However, when habitat models were incomplete (e.g. lack of information about resources and habitats in the landscape) – as in all field studies – spurious preference for familiar locations arose. Our study aids the interpretation of behavioural mechanisms in habitat selection studies, but also calls for a more thorough study of the approaches used to infer behavioural mechanisms in habitat selection studies.
Productivity–diversity patterns in arctic tundra vegetation
Authors: Virtanen Risto , Grytnes John‐Arvid , Lenoir Jonathan , Luoto Miska , Oksanen Jari , Oksanen Lauri , Svenning Jens‐Christian
Published: September 2012

Productivity has long been argued to be a major driver of species richness patterns. In the present study we test alternative productivity–diversity hypotheses using vegetation data from the vast Eurasian tundra. The productivity–species pool hypothesis predicts positive relationships at both fine and coarse grain sizes, whereas the productivity–interaction hypothesis predicts unimodal patterns at fine grain size, and monotonic positive patterns at coarse grain size. We furthermore expect to find flatter positive (productivity–species pool hypothesis) or more strongly negative (productivity–interaction hypothesis) relationships for lichens and bryophytes than for vascular plants, because as a group, lichens and bryophytes are better adapted to extreme arctic conditions and more vulnerable to competition for light than the taller‐growing vascular plants. The normalised difference vegetation index (NDVI) was used as a proxy of productivity. The generally unimodal productivity–diversity patterns were most consistent with the productivity–interaction hypothesis. There was a general trend of decreasing species richness from moderately to maximally productive tundra, in agreement with an increasing importance of competitive interactions. High richness of vascular plants and lichens occurred in moderately low productive tundra areas, whereas that of bryophytes occurred in the least productive tundra habitats covered by this study. The fine and coarse grain richness trends were surprisingly uniform and no variation in beta diversity along the productivity gradient was seen for vascular plants or bryophytes. However, lichen beta diversity varied along the productivity gradient, probably reflecting their sensitivity to habitat conditions and biotic interactions. Overall, the results show evidence that productivity–diversity gradients exist in tundra and that these appear to be largely driven by competitive interactions. Our results also imply that climate warming‐driven increases in productivity will strongly affect arctic plant diversity patterns.
Genetic load is associated with hypothalamic–pituitary–adrenal axis dysregulation in macaques
Authors: Ferguson B. , Hunter J. E. , Luty J. , Street S. L. , Woodall A. , Grant K. A.
Published: September 2012

Dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis pathway is associated with several neuropsychiatric disorders, including post‐traumatic stress disorder (PTSD), major depressive disorder (MDD), schizophrenia and alcohol abuse. Studies have demonstrated an association between HPA axis dysfunction and gene variants within the cortisol, serotonin and opioid signaling pathways. We characterized polymorphisms in genes linked to these three neurotransmitter pathways and tested their potential interactions with HPA axis activity, as measured by dexamethasone (DEX) suppression response. We determined the percent DEX suppression of adrenocorticotropic hormone (ACTH) and cortisol in 62 unrelated, male rhesus macaques. While DEX suppression of cortisol was robust amongst 87% of the subjects, ACTH suppression levels were broadly distributed from −21% to 66%. Thirty‐seven monkeys from the high and low ends of the ACTH suppression distribution (18 ‘high’ and 19 ‘low’ animals) were genotyped at selected polymorphisms in five unlinked genes (rhCRH, rhTPH2, rhMAOA, rhSLC6A4 and rhOPRM). Associations were identified between three variants (rhCRH‐2610C>T, rhTPH2 2051A>C and rh5‐HTTLPR) and level of DEX suppression of ACTH. In addition, a significant additive effect of the ‘risk’ genotypes from these three loci was detected, with an increasing number of ‘risk’ genotypes associated with a blunted ACTH response (P = 0.0009). These findings suggest that assessment of multiple risk alleles in serotonin and cortisol signaling pathway genes may better predict risk for HPA axis dysregulation and associated psychiatric disorders than the evaluation of single gene variants alone.
Genome‐wide analysis of Nilaparvata lugens nymphal responses to high‐density and low‐quality rice hosts
Authors: Hu Ding‐Bang , Luo Bing‐Qing , Li Jie , Han Yu , Jiang Ting‐Ru , Liu Jia , Wu Gang , Hua Hong‐Xia , Xiong Yan‐Fei , Li Jun‐Sheng
Published: September 2012

The brown planthopper (BPH) Nilaparvata lugens is an economically important pest on rice plants. In this study, the higher population density and yellow‐ripe stage of rice plants were used to construct adverse survival conditions (ASC) against BPH nymphs. Simultaneously, the low population density and tillering stage of rice plants were used to establish a suitable survival condition (SSC) as a control. Solexa/Illumina sequencing was used to identify genes of BPH nymphs responding to ASC. Significantly longer duration development of BPH nymphs and significantly lower brachypterous ratio of BPH adults were observed by ASC compared with SSC. A total of 2 544 differentially expressed genes (DEGs) were obtained and analyzed by BLASTx, Gene Ontology and KEGG Orthology. Gene ontology analysis revealed that the DEGs were mainly involved in categories of cell, cell part, cellular process, binding, catalytic, organelle and metabolic processes. 1 138 DEGs having enzyme commission numbers were assigned to different metabolic pathways. The largest clusters were neurodegenerative diseases (137, 12.0%), followed by carbohydrate metabolism (113, 9.9%), amino acid metabolism (94, 8.3%), nucleotide metabolism (76, 6.7%), energy metabolism (64, 5.6%), translation (60, 5.3%), lipid metabolism (58, 5.1%), and folding, sorting and degradation (52, 4.6%). Expressing profile of 11 DEGs during eight nymphal developmental stages of BPH were analyzed by quantitative real‐time polymerase chain reaction. The 11 genes exhibited differential expression between ASC and SSC during at least one developmental stage. The DEGs identified in this study provide molecular proof of how BPH reconfigures its gene expression profile to adapt to overcrowding and low‐quality hosts.
The Political Geographies of Urban Polarization: A Critical Review of Research on Divided Cities
Authors: Allegra Marco , Casaglia Anna , Rokem Jonathan
Published: September 2012

This article aims at providing a review of various streams of literature dealing with the spatial fragmentation of cities. In the last two decades many different contributions emphasized the growing fragmentation of the urban environment; the idea of “divided city” covers a multiplicity of approaches, methodologies and field of research. Still, the “divided city” literature tends to elevate a small number of cities to paradigmatic examples and to focus on abstract categories based on single factor explanations of urban fragmentation. The article, while accepting the hypothesis that the urban context is increasingly fragmented, argues that systems of coordinates – more than a taxonomy or a hierarchy – is needed to make sense of this phenomenon and draw significan comparison between cities. The article also maintains that a significant angle to look at urban polarization relates to the configuration of urban governance and political power. The article therefore considers three main areas connected to the distinction between polity, politics, and policy – and the three corresponding ideal‐types of partitioned, contested and discrete city – where the conflict focuses respectively on the jurisdictional shape of governance, the degrees and venues of access to decision‐making, and frame and contents of public policies.
The feral horse foot. Part A: observational study of the effect of environment on the morphometrics of the feet of 100Australian feral horses
Authors: Hampson BA , de Laat MA , Mills PC , Pollitt CC
Published: September 2012

Aim

To better understand the morphology of, and the effect of different travel patterns and varying substrate environments on, the feral horse foot to better manage the feet of domestic horses.

Methods

The left forefeet of 20 adult feral horses from each of five geographically separated populations in Australia (n = 100) were investigated. Populations were selected on the basis of substrate hardness under foot and the amount of travel typical for the population. Feet were radiographed and photographed and 40 morphometric measurements of each foot were obtained.

Results

Of the 40 parameters, 37 differed significantly (P < 0.05) among the populations, which suggested that substrate hardness and travel distance have an effect on foot morphology. Harder substrates and longer travel distances were associated with short hoof walls and minimal hoof wall flaring. Softer substrates and moderate travel distances were associated with long flared walls, similar to that of typical untrimmed feet of domestic horses.

Conclusions

The morphology of the feral horse foot appeared to be affected by the distance travelled and by the abrasive qualities and mechanical properties of the substrate under foot. There were marked differences in some conformation parameters between the feral horses in the current study and domestic horses in previous studies. Although the conformation of the feral horse foot may have some prescriptive value, concerns regarding abnormal foot anatomy warrant further investigation.
Use of online sources of information by dental practitioners: findings from The Dental Practice‐Based Research Network
Authors: Funkhouser Ellen , Agee Bonita S. , Gordan Valeria V. , Rindal D. Brad , Fellows Jeffrey L. , Qvist Vibeke , McClelland Jocelyn , Gilbert Gregg H. ,   The DPBRN Collaborative Group
Published: September 2012

Objective: Estimate the proportion of dental practitioners who use online sources of information for practice guidance.

Methods: From a survey of 657 dental practitioners in The Dental Practice‐Based Research Network, four indicators of online use for practice guidance were calculated: read journals online, obtained continuing education (CDE) through online sources, rated an online source as most influential, and reported frequently using an online source for guidance. Demographics, journals read, and use of various sources of information for practice guidance in terms of frequency and influence were ascertained for each.

Results: Overall, 21 percent (n = 138) were classified into one of the four indicators of online use: 14 percent (n = 89) rated an online source as most influential and 13 percent (n = 87) reported frequently using an online source for guidance; few practitioners (5 percent, n = 34) read journals online, fewer (3 percent, n = 17) obtained CDE through online sources. Use of online information sources varied considerably by region and practice characteristics. In general, the four indicators represented practitioners with as many differences as similarities to each other and to offline users.

Conclusion: A relatively small proportion of dental practitioners use information from online sources for practice guidance. Variation exists regarding practitioners' use of online source resources and how they rate the value of offline information sources for practice guidance.
Need of minimal important difference for oral health‐related quality of life measures
Authors: Masood Mohd , Masood Yaghma , Saub Roslan , Newton Jonathan Timothy
Published: September 2012

Demand and use for oral health‐related quality of life (OHRQoL) instruments have increased in recent years in both research and clinical settings. These instruments can be used to measure patient's health status or detect changes in a patient's health status in response to an intervention or changes in disease trajectory. Ensuring universal acceptance of these measures requires easy interpretation of its scores for clinicians, researchers, and patients. The most important way of describing and interpreting this significance of changes in OHRQoL is through the establishment of minimal important difference (MID). The minimally important difference represents the smallest improvement considered worthwhile by a patient. A comprehensive search of published literature identified only 12 published articles on establishment of MID for OHRQoL measures. This scarcity of published studies on MID encourages the need of appropriate interpretation and describing patient satisfaction in reference to that treatment using MID. Anchor‐ and distribution‐based methods are the two general approaches that have been proposed and recommended to interpret differences or changes in OHRQoL. Both of these methods of determining the MID have specific shortcomings; therefore, it is proposed to adopt triangulation approaches in which the methods are combined. The objective of this review is to summarize the need for, importance of, and recommendations for methods of establishing MID for OHRQoL measures.
Effect of genistein, a natural soy isoflavone, on the pharmacokinetics and intestinal toxicity of irinotecan hydrochloride in rats
Authors: Yokooji Tomoharu , Kawabe Yoshihiro , Mori Nobuhiro , Murakami Teruo
Published: September 2012

Objectives

The effect of genistein, a natural soy isoflavone, on pharmacokinetics and intestinal toxicity, or late-onset diarrhoea, of irinotecan hydrochloride (CPT-11) was examined in rats.

Methods

Probenecid, a typical inhibitor of multidrug resistance-associated protein (MRP) 2, was also employed for comparison with genistein. Plasma concentration, biliary excretion and intestinal secretion of CPT-11, 7-ethyl-10-hydroxycamptothecin (SN-38) and SN-38 glucuronide (SN-38G) were determined in untreated, genistein-treated and probenecid-treated rats. CPT-11 was administered repeatedly by intravenous injection (60 mg/kg/day for 4 days), and the effects of genistein and probenecid on CPT-11-induced intestinal toxicity were evaluated by measuring body weight, induction of diarrhoea, and alkaline phosphatase (ALP) activity in the intestinal mucosal membranes.

Key findings

Genistein, as well as probenecid, significantly suppressed the MRP2-mediated biliary and intestinal secretion of CPT-11 and its metabolites and increased their plasma concentrations. Multiple administration of CPT-11 reduced body weight and ALP activity, and induced watery diarrhoea. Genistein, as well as probenecid, significantly suppressed the loss in body weight and the reduced mucosal ALP activity in the ileum, and ameliorated the symptoms of diarrhoea induced by CPT-11.

Conclusions

Intravenous genistein was effective in ameliorating CPT-11-induced late-onset diarrhoea, by suppressing MRP2-mediated biliary excretion of CPT-11 and its metabolites.
The potential role of fatty liver in paediatric metabolic syndrome: a distinct phenotype with high metabolic risk?
Authors: Nobili V. , Bedogni G. , Berni Canani R. , Brambilla P. , Cianfarani S. , Pietrobelli A. , Agostoni C.
Published: September 2012

Background

The prevalence of obesity and its metabolic consequences has dramatically increased in the last two decades urging physicians to find a reliable definition for early detection, treatment and possibly prevention of metabolic syndrome (MS). MS could be diagnosed in adult patients in the presence of a large waist circumference and ≥2 of the following features: high serum triglycerides, low serum high‐density lipoprotein cholesterol, high blood pressure and high fasting glucose. The definition of MS in children is more problematic, and the potential role of its single components on metabolic risk remains largely undefined. Recent evidence strongly suggests not only a relationship between non‐alcoholic fatty liver disease (NAFLD) and MS in obese children, adolescents and adults, but also the key role exerted by liver fat deposition in the pathogenesis of MS.

Conclusion

We propose that NAFLD should be routinely checked in obese subjects because early lifestyle changes may be effective in reducing the overall risk of MS.
On the Oxford Handbook of Global Modernisms; or the New WWJD
Authors: Yao Steven
Published: September 2012

In this paper, I discuss the role of Fredric Jameson in The Oxford Handbook of Global Modernisms. In particular, I reflect briefly on the advantages and limits of Jameson’s “singular modernity” thesis as a paradigm for global for modernist studies.
Multiplied Modernities and Modernisms?
Authors: Wang Ning
Published: September 2012

There are different forms of modernity or modernism since there is no such thing as the so‐called “singular modernity” or modernism. The paper illustrates how Chinese modernity or modernism has formed to deconstruct the “singular modernity” and Westcentric form of modernism. As an alternative modernity or modernism, the rise of Chinese modernity or modernism has not only contributed to the grand narrative discourse of global modernity or modernism but also paved the way for different forms of modernity or modernism in the current world.
A disproportionate role for mtDNA in Dobzhansky–Muller incompatibilities?
Authors: Burton Ronald S. , Barreto Felipe S.
Published: September 2012

Evolution in allopatric populations can lead to incompatibilities that result in reduced hybrid fitness and ultimately reproductive isolation upon secondary contact. The Dobzhansky–Muller (DM) model nicely accounts for the evolution of such incompatibilities. Although DM incompatibilities were originally conceived as resulting of interactions between nuclear genes, recent studies have documented cases where incompatibilities have arisen between nuclear and mitochondrial genomes (mtDNA). Although mtDNA comprises only a tiny component (typically ≪0.01%) of an organism's genetic material, several features of mtDNA may lead to a disproportionate contribution to the evolution of hybrid incompatibilities: (i) essentially all functions of mtDNA require interaction with nuclear gene products. All mtDNA‐encoded proteins are components of the oxidative phosphorylation (OXPHOS) system and all mtDNA‐encoded RNAs are part of the mitochondrial protein synthetic machinery; both processes require interaction with nuclear‐encoded proteins for function. (ii) Transcription and replication of mtDNA also involve mitonuclear interactions as nuclear‐encoded proteins must bind to regulatory motifs in the mtDNA to initiate these processes. (iii) Although features of mtDNA vary amongst taxa, metazoan mtDNA is typically characterized by high nucleotide substitution rates, lack of recombination and reduced effective population sizes that collectively lead to increased chance fixation of mildly deleterious mutations. Combined, these features create an evolutionary dynamic where rapid mtDNA evolution favours compensatory nuclear gene evolution, ultimately leading to co‐adaptation of mitochondrial and nuclear genomes. When previously isolated lineages hybridize in nature or in the lab, intergenomic co‐adaptation is disrupted and hybrid breakdown is observed; the role of intergenomic co‐adaptation in hybrid breakdown and speciation will generally be most pronounced when rates of mtDNA evolution are high or when restricted gene flow results in significant population differentiation.
Peptidoglycan maturation enzymes affect flagellar functionality in bacteria
Authors: Roure Sophie , Bonis Mathilde , Chaput Catherine , Ecobichon Chantal , Mattox Austin , Barrière Charlotte , Geldmacher Nina , Guadagnini Stéphanie , Schmitt Christine , Prévost Marie‐Christine , Labigne Agnès , Backert Steffen , Ferrero Richard L. , Boneca Ivo G.
Published: September 2012

The flagellar machinery is a highly complex organelle composed of a free rotating flagellum and a fixed stator that converts energy into movement. The assembly of the flagella and the stator requires interactions with the peptidoglycan layer through which the organelle has to pass for externalization. Lytic transglycosylases are peptidoglycan degrading enzymes that cleave the sugar backbone of peptidoglycan layer. We show that an endogenous lytic transglycosylase is required for full motility of Helicobacter pylori and colonization of the gastric mucosa. Deficiency of motility resulted from a paralysed phenotype implying an altered ability to generate flagellar rotation. Similarly, another Gram‐negative pathogen Salmonella typhimurium and the Gram‐positive pathogen Listeria monocytogenes required the activity of lytic transglycosylases, Slt or MltC, and a glucosaminidase (Auto), respectively, for full motility. Furthermore, we show that in absence of the appropriate lytic transglycosylase, the flagellar motor protein MotB from H. pylori does not localize properly to the bacterial pole. We present a new model involving the maturation of the surrounding peptidoglycan for the proper anchoring and functionality of the flagellar motor.
Why only some plants emit isoprene
Authors: MONSON RUSSELL K. , JONES RYAN T. , ROSENSTIEL TODD N. , SCHNITZLER JÖRG‐PETER
Published: September 2012

Isoprene (2‐methyl‐1,3‐butadiene) is emitted from many plants and it appears to have an adaptive role in protecting leaves from abiotic stress. However, only some species emit isoprene. Isoprene emission has appeared and been lost many times independently during the evolution of plants. As an example, our phylogenetic analysis shows that isoprene emission is likely ancestral within the family Fabaceae (= Leguminosae), but that it has been lost at least 16 times and secondarily gained at least 10 times through independent evolutionary events. Within the division Pteridophyta (ferns), we conservatively estimate that isoprene emissions have been gained five times and lost two times through independent evolutionary events. Within the genus Quercus (oaks), isoprene emissions have been lost from one clade, but replaced by a novel type of light‐dependent monoterpene emissions that uses the same metabolic pathways and substrates as isoprene emissions. This novel type of monoterpene emissions has appeared at least twice independently within Quercus, and has been lost from 9% of the individuals within a single population of Quercus suber. Gain and loss of gene function for isoprene synthase is possible through relatively few mutations. Thus, this trait appears frequently in lineages; but, once it appears, the time available for evolutionary radiation into environments that select for the trait is short relative to the time required for mutations capable of producing a non‐functional isoprene synthase gene. The high frequency of gains and losses of the trait and its heterogeneous taxonomic distribution in plants may be explained by the relatively few mutations necessary to produce or lose the isoprene synthase gene combined with the assumption that isoprene emission is advantageous in a narrow range of environments and phenotypes.
Arf6 Regulation of Gyrating‐Clathrin
Authors: Luo Yi , Zhan Yi , Keen James H.
Published: September 2012

‘Gyrating‐’ or ‘G’‐clathrin are coated endocytic structures located near peripheral sorting endosomes (SEs), which exhibit highly dynamic but localized movements when visualized by live‐cell microscopy. They have been implicated in recycling of transferrin from the sorting endosome directly to the cell surface, but there is no information about their formation or regulation. We show here that G‐clathrin comprise a minority of clathrin‐coated structures in the cell periphery and are brefeldin A (BFA)‐resistant. Arf6‐GTP substantially increases G‐clathrin levels, probably by lengthening coated bud lifetimes as suggested by photobleaching and photoactivation results, and an Arf6(Q67L)‐GTP mutant bearing an internal GFP tag can be directly visualized in G‐clathrin structures in live cells. Upon siRNA‐mediated depletion of Arf6 or expression of Arf6(T27N), G‐clathrin levels rise and are primarily Arf1‐dependent, yet still BFA‐resistant. However, BFA‐sensitive increased G‐clathrin levels are observed upon acute incubation with cytohesin inhibitor SecinH3, indicating a shift in GEF usage. Depletion of both Arf6 and Arf1 abolishes G‐clathrin, and results in partial inhibition of fast transferrin recycling consistent with the latter's participation in this pathway. Collectively, these results demonstrate that the dynamics of G‐clathrin primarily requires completion of the Arf6 guanine nucleotide cycle, but can be regulated by multiple Arf and GEF proteins, reflecting both overlapping mechanisms operative in their regulation and the complexity of processes involved in endosomal sorting.
Crack Detection in a Rotor Dynamic System by Vibration
Monitoring—Part II: Extended Analysis and Experimental Results
Authors: Varney Philip , Green Itzhak
Published: September 2012

An increase in the power-to-weight ratio demand on rotordynamic systems causes increased susceptibility to transverse fatigue cracking of the shaft. The ability to detect cracks at an early stage of progression is imperative for minimizing off-line repair time and cost. The vibration monitoring system initially proposed in Part I is employed herein, using the 2X harmonic response component of the rotor tilt as a signature indicating a transverse shaft crack. In addition, the analytic work presented in Part I is expanded to include a new notch crack model to better approximate experimental results. To effectively capture the 2X response, the crack model must include the local nature of the crack, the depth of the crack, and the stiffness asymmetry inducing the gravity-forced 2X harmonic response. The transfer matrix technique is well suited to incorporate these crack attributes due to its modular nature. Two transfer matrix models are proposed to predict the 2X harmonic response. The first model applies local crack flexibility coefficients determined using the strain energy release rate, while the second incorporates the crack as a rectangular notch to emulate a manufactured crack used in the experiments. Analytic results are compared to experimental measurement of the rotor tilt gleaned from an overhung rotor test rig originally designed to monitor seal face dynamics. The test rig is discussed, and experimental angular response orbits and 2X harmonic amplitudes of the rotor tilt are provided for shafts containing manufactured cracks of depths between 0% and 40%. Feasibility of simultaneous multiple-fault detection of transverse shaft cracks and seal face contact is discussed.
SiO2/TiO2 Antireflective Coatings With Photocatalytic Properties Prepared by Sol–Gel for Solar Glass Covers
Authors: San Vicente G. , Morales A. , Germán N. , Suarez S. , Sánchez B.
Published: September 2012

The glass covers of solar systems are usually coated with antireflective (AR) coatings on both sides that allow to increase the efficiency of the whole system. At the same time, the accumulation of dust and dirt particles on the surface of the AR coated glass decreases the transmittance of the covers, even to values lower than the uncoated glass. This decrease in the cover transmittance reduces the solar radiation that reaches the absorber and, in this way, a decrease in the solar plant efficiency would be obtained. So, the use of films that combine high transmittance and self-cleaning capacity seems to be a promising development. This paper reports the preparation of sol–gel porous TiO2 and SiO2 bilayers on borosilicate glass. The porosity and thickness of both layers have been optimized in order to obtain the optimal photocatalytic and optical properties. Solar transmittance values of 0.964 were obtained for the TiO2/SiO2 coated glass. The highest value of transmittance reached is 0.993 and it is placed at 600 nm. The self-cleaning properties were evaluated using methylene blue and trichloroethylene (TCE) as model organic molecules using UV-A light. The results showed that the SiO2/TiO2 samples degraded the colorant faster than the SiO2 sample. Moreover, the degradation of TCE in air in a continuous fix bed photoreactor for samples with different TiO2 film thicknesses was also performed. The TCE conversion was found dependent on the TiO2 thickness. Nevertheless, the increase in the thickness of this layer reduced transmittance properties. The study demonstrates that it is possible to combine antireflective and self-cleaning properties in the same material.
Analytical Analysis of Indirect Combustion Noise in Subcritical Nozzles
Authors: Giauque Alexis , Huet Maxime , Clero Franck
Published: September 2012

This article revisits the problem of indirect combustion noise in nozzles of finite length. The analytical model proposed by Moase for indirect combustion noise is rederived and applied to subcritical nozzles having shapes of increasing complexity. This model is based on the equations formulated by Marble and Candel for which an explicit solution is obtained in the subsonic framework. The discretization of the nozzle into n elementary units of finite length implies the determination of 2n integration constants for which a set of linear equations is provided in this article. The analytical method is applied to configurations of increasing complexity. Analytical solutions are compared to numerical results obtained using SUNDAY (a 1D nonlinear Euler solver in temporal space) and CEDRE (3D Navier–Stokes flow solver). Excellent agreement is found for all configurations thereby showing that acceleration discontinuities at the boundaries between adjacent elements do not influence the actual acoustic transfer functions. The issue of nozzle compactness is addressed. It is found that in the subcritical domain, spectral results should be nondimensionalized using the flow-through-time of the entire nozzle. Doing so, transfer functions of nozzles of different lengths are successfully compared and a compactness criterion is proposed that writes ω*∫0Ldζ/u(ζ)<1 where L is the axial length of the nozzle. Finally, the entropy wave generator (EWG) experimental setup is considered. Analytical results are compared to the results reported by Howe. Both models give similar trends and show the important role of the rising time of the fluctuating temperature front on the amplitude of the indirect acoustic emission. The experimental temperature profile and the impedance coefficients at the inlet and outlet are introduced into the analytical formulation. Results show that the indirect combustion noise mechanism is not alone responsible for the acoustic emission in the subcritical case.
Characterization of Stiffness and Damping in Textured Sector Pad Micro Thrust Bearings Using Computational Fluid Dynamics
Authors: Papadopoulos Christos I. , Nikolakopoulos Pantelis G. , Kaiktsis Lambros
Published: September 2012

In the present paper, a study of stiffness and damping in sector-pad micro thrust bearings with artificial surface texturing is presented, based on computational fluid dynamics (CFD) simulations. The bearing pads are modeled as consecutive three-dimensional independent microchannels, each consisting of a smooth rotating wall (rotor) and a partially textured stationary wall (stator). CFD simulations are performed, consisting in the numerical solution of the Navier–Stokes equations for incompressible isothermal flow. The goal of the present study is to characterize the dynamic behavior of favorable designs, identified in previous optimization studies, comprising parallel and convergent thrust bearings with rectangular texture patterns. To this end, a translational degree of freedom (DOF) along the thrust direction and a rotational (tilting) DOF of the rotor are considered. By implementing appropriate small perturbations around the equilibrium (steady-state) position and processing the simulation results, the stiffness and damping coefficients of the bearing are obtained for each DOF. The computed dynamic coefficients of textured thrust bearings are compared to those of conventional (smooth slider) designs. It is found that the dependence of bearing stiffness and damping on geometrical parameters exhibits the same trends for both DOFs. Both stiffness and damping are found to increase with bearing width. In general, increasing the bearing convergence ratio results in increased bearing stiffness and decreased damping. Finally, the present results demonstrate that properly textured parallel sliders are characterized by an overall dynamic performance that is superior to that of smooth converging sliders.
Characterization of aortic remodeling following Kawasaki disease: Toward a fully developed automatic biparametric model
Authors: Maurice Roch L. , Dahdah Nagib
Published: September 2012

Purpose:

Mechanical properties of the arteries are essential in assessing cardiovascular diseases. New imaging modalities that allow mapping strain, shear and elasticity distributions within the arterial wall are rapidly evolving. Very recently, our group introduced an iterative optical flow‐based elastography method devoted to B‐mode data. In this paper, the authors propose an adaptation of the optical flow method to investigate aortic remodeling following Kawasaki disease, an early childhood vasculitis. Namely, displacement and strain of the aortic wall are used to assess aortic stiffness in this human disease model. The authors also introduce a fully developed automatic method to support postprocessing data analysis.

Methods:

The sequalae of Kawasaki disease on the ascending aorta were examined in children. The pathologic population (n = 4) was 15.00 ± 2.45 years old, while the healthy control population (n = 5) was 13.13 ± 0.18 years old. B‐mode data were digitally recorded with commercially available cardiac echocardiography machines.

Results:

Kawasaki disease had a very significant impact on the aortic stiffness. Indeed, pathologic subjects’ aortic wall strain estimate was significantly lower compared to healthy controls (2.75% ± 0.56% versus 4.24% ± 0.65%, respectively;p < 0.001). Similarly, displacement of the aortic wall was also significantly lower compared to controls (p < 0.001).

Conclusions:

The potential of the optical flow‐based method to quantify aortic wall remodeling in a human disease model was demonstrated. The authors now intend to extend this investigation to a larger pathologic cohort with various degrees of vasculitis severity.
Three‐dimensional radiobiological dosimetry of kidneys for treatment planning in peptide receptor radionuclide therapy
Authors: Baechler Sébastien , Hobbs Robert F. , Boubaker Ariane , Buchegger Franz , He Bin , Frey Eric C. , Sgouros George
Published: September 2012

Purpose:

Peptide receptor radionuclide therapy (PRRT) delivers high absorbed doses to kidneys and may lead to permanent nephropathy. Reliable dosimetry of kidneys is thus critical for safe and effective PRRT. The aim of this work was to assess the feasibility of planning PRRT based on 3D radiobiological dosimetry (3D‐RD) in order to optimize both the amount of activity to administer and the fractionation scheme, while limiting the absorbed dose and the biological effective dose (BED) to the renal cortex.

Methods:

Planar and SPECT data were available for a patient examined with111In‐DTPA‐octreotide at 0.5 (planar only), 4, 24, and 48 h post‐injection. Absorbed dose and BED distributions were calculated for common therapeutic radionuclides, i.e., 111In, 90Y and 177Lu, using the 3D‐RD methodology. Dose‐volume histograms were computed and mean absorbed doses to kidneys, renal cortices, and medullae were compared with results obtained using the MIRD schema (S‐values) with the multiregion kidney dosimetry model. Two different treatment planning approaches based on (1) the fixed absorbed dose to the cortex and (2) the fixed BED to the cortex were then considered to optimize the activity to administer by varying the number of fractions.

Results:

Mean absorbed doses calculated with 3D‐RD were in good agreement with those obtained with S‐value‐based SPECT dosimetry for90Y and 177Lu. Nevertheless, for 111In, differences of 14% and 22% were found for the whole kidneys and the cortex, respectively. Moreover, the authors found that planar‐based dosimetry systematically underestimates the absorbed dose in comparison with SPECT‐based methods, up to 32%. Regarding the 3D‐RD‐based treatment planning using a fixed BED constraint to the renal cortex, the optimal number of fractions was found to be 3 or 4, depending on the radionuclide administered and the value of the fixed BED. Cumulative activities obtained using the proposed simulated treatment planning are compatible with real activities administered to patients in PRRT.

Conclusions:

The 3D‐RD treatment planning approach based on the fixed BED was found to be the method of choice for clinical implementation in PRRT by providing realistic activity to administer and number of cycles. While dividing the activity in several cycles is important to reduce renal toxicity, the clinical outcome of fractionated PRRT should be investigated in the future.
The effects of incidence angle on film dosimetry and their consequences in IMRT dose verification
Authors: Srivastava R. P. , Wagter C. De
Published: September 2012

Purpose:

The dosimetric accuracy of EDR2 radiographic film has been rigorously assessed in regular and intensity modulated beams for various incidence angles, including the parallel and perpendicular orientation. There clearly exists confusion in literature regarding the effect of film orientation. The primary aim is to clarify potential sources of the confusion and to gain physical insight into the film orientation effect with a link to radiochromic film as well.

Methods:

An inverse pyramid IMRT field, consisting of six regular and elongated 3 × 20 cm2 field segments, was studied in perpendicular and parallel orientation. Assessment of film self‐perturbation and intrinsic directional sensitivity were also included in the experiments. Finally, the authors investigated the orientational effect in composite beams in the two extreme orientations, i.e., perpendicular and parallel.

Results:

The study of an inverse pyramid dose profile revealed good agreement between the perpendicular film and the diamond detector within 0.5% in the low‐scatter regions for both 6 and 18 MV. The parallel oriented film demonstrated a 3% under‐response at 5‐cm (6 MV) depth against the perpendicular orientation, but both orientations over responded equally in the central region, which received only scattered dose, at both 5‐ and 20‐cm depths. In a regular 6‐MV 5 × 5 cm2 field, a 4.1% lower film response was observed in the parallel orientation compared to perpendicular orientation. The under response gradually increased to 6% when reducing the field size to 0.5 × 5 cm2. On the other hand, the film showed a 1.7% lower response in parallel orientation for the large field size of 20 × 20 cm2 at 5‐cm depth but the difference disappeared at 10 cm. At 18 MV, similar but somewhat lower differences were found between the two orientations. The directional sensitivity of the film diminishes with increasing field size and depth. Surprisingly a composite IMRT beam consisting of 20 adjacent strip segments also produced a significant orientational dependence of film response, notwithstanding the large total field size of 20 × 20 cm2.

Conclusions:

This analysis allowed the development of a hypothesis about the physics behind the orientational dependence of film response in general and to formulate precautions when using film dosimetry in the dosimetric verification of multibeam treatments.
Elemental Mapping by Dawn Reveals Exogenic H in Vesta’s Regolith
Authors: Prettyman Thomas H. , Mittlefehldt David W. , Yamashita Naoyuki , Lawrence David J. , Beck Andrew W. , Feldman William C. , McCoy Timothy J. , McSween Harry Y. , Toplis Michael J. , Titus Timothy N. , Tricarico Pasquale , Reedy Robert C. , Hendricks John S. , Forni Olivier , Le Corre Lucille , Li Jian-Yang , Mizzon Hugau , Reddy Vishnu , Raymond Carol A. , Russell Christopher T.
Published: September 2012

Vesta to the Core

Vesta is one of the largest bodies in the main asteroid belt. Unlike most other asteroids, which are fragments of once larger bodies, Vesta is thought to have survived as a protoplanet since its formation at the beginning of the solar system (see the Perspective by
Binzel
, published online 20 September). Based on data obtained with the Gamma Ray and Neutron Detector aboard the Dawn spacecraft,

Prettyman
et al.

(p.
242
, published online 20 September) show that Vesta's reputed volatile-poor regolith contains substantial amounts of hydrogen delivered by carbonaceous chondrite impactors. Observations of pitted terrain on Vesta obtained by Dawn's Framing Camera and analyzed by

Denevi
et al.

(p.
246
, published online 20 September), provide evidence for degassing of volatiles and hence the presence of hydrated materials. Finally, paleomagnetic studies by

Fu
et al.

(p.
238
) on a meteorite originating from Vesta suggest that magnetic fields existed on the surface of the asteroid 3.7 billion years ago, supporting the past existence of a magnetic core dynamo.
Detecting Causality in Complex Ecosystems
Authors: Sugihara George , May Robert , Ye Hao , Hsieh Chih-hao , Deyle Ethan , Fogarty Michael , Munch Stephan
Published: September 2012

Cause or Correlation?

Three centuries ago, Bishop Berkeley's 1710 classic “A treatise on the nature of human knowledge,” first spelled out the “correlation vs. causation” dilemma.Sugiharaet al.(p.496, published online 20 September) present an approach to this conundrum, and extend current discussions about causation to dynamic systems with weak to moderate coupling (such as ecosystems). The resulting method, convergent cross mapping can detect causal linkages between time series.
Differences in taste sensitivity between obese and non-obese children and adolescents
Authors: Overberg Johanna , Hummel Thomas , Krude Heiko , Wiegand Susanna
Published: September 2012

Background

Taste sensitivity varies between individuals. Several studies describe differences between obese and non-obese subjects concerning their taste perception. However, data are partly contradictory and insufficient. Therefore, in this study taste sensitivity of obese and non-obese children/adolescents was analysed.

Methods

In a cross-sectional study gustatory sensitivity of n=99 obese subjects (body mass index (BMI) >97th percentile) and n=94 normal weight subjects (BMI <90th percentile), 6–18 years of age, was compared. Sensitivity for the taste qualities sweet, sour, salty, umami and bitter was analysed by means of impregnated ‘taste strips’ in different concentrations. A total score was determined for all taste qualities combined as well as for each separately. Furthermore, the possible influence of sex, age and ethnicity on taste perception was analysed. An intensity rating for sweet was performed on a 5-point rating scale.

Results

Obese subjects showed—compared to the control group—a significantly lower ability to identify the correct taste qualities regarding the total score (p<0.001). Regarding individual taste qualities there was a significantly lower detection rate for salty, umami and bitter by obese subjects. Furthermore, the determinants age and sex had a significant influence on taste perception: older age and female sex was associated with better ability to identify taste qualities. Concerning the sweet intensity rating obese children gave significantly lower intensity ratings to three of the four concentrations.

Conclusions

Obese and non-obese children and adolescents differ in their taste perception. Obese subjects could identify taste qualities less precisely than children and adolescents of normal weight.
Sulphadiazine-induced renal stones in a 63-year-old HIV-infected man treated for toxoplasmosis
Authors: David McGettigan Benjamin , Hew Meilyn , Phillips Elizabeth , McLean-Tooke Andrew
Published: September 2012

A 63-year-old man was admitted for investigation of blurred vision and multiple ring-enhancing lesions on cranial MRI. Histopathological examination of tissue obtained at brain biopsy showed multipleToxoplasma gondiicysts. He was started on a combination of sulphadiazine and pyrimethamine for cerebral toxoplasmosis and was subsequently diagnosed with HIV-1 infection. He then developed acute renal failure and flank pain and was diagnosed with bilateral vesico-uretric calculi requiring bilateral stent insertion. The retrieved renal calculi were negative for the common stones that are routinely tested for in our laboratory and had the macroscopic characteristics of a sulphadiazine stone. His renal failure responded to cessation of the sulphadiazine.