bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of EU Antitrust Investigations and Fines on a Firm's Valuation
Authors: Aguzzoni Luca , Langus Gregor , Motta Massimo
Published: July 2013

EU antitrust investigations involve a sequence of events which affect the investigated firm's market value. We model these relationships and estimate their impact on firms' share prices. On average, a surprise inspection reduces a firm's share price by 2.89%, an infringement decision reduces it by 3.57%. The Court judgments do not have a statistically significant effect. Overall, we find that the total effect of the antitrust action ranges from −3.03% to −4.55% of a firm's market value. Fines account for no more than 8.9% of this loss, and we conjecture that most of the loss is due to the cessation of illegal activities.
Breast cancer as a systemic disease: a view of metastasis
Authors: Redig A. J. , McAllister S. S.
Published: July 2013

Breast cancer is now the most frequently diagnosed cancer and leading cause of cancer death in women worldwide. Strategies targeting the primary tumour have markedly improved, but systemic treatments to prevent metastasis are less effective; metastatic disease remains the underlying cause of death in the majority of patients with breast cancer who succumb to their disease. The long latency period between initial treatment and eventual recurrence in some patients suggests that a tumour may both alter and respond to the host systemic environment to facilitate and sustain disease progression. Results from studies in animal models suggest that specific subtypes of breast cancer may direct metastasis through recruitment and activation of haematopoietic cells. In this review, we focus on data implicating breast cancer as a systemic disease.
Evaluation of palatability of 10 commercial amlodipine orally disintegrating tablets by gustatory sensation testing, OD-mate as a new disintegration apparatus and the artificial taste sensor
Authors: Uchida Takahiro , Yoshida Miyako , Hazekawa Mai , Haraguchi Tamami , Furuno Hiroyuki , Teraoka Makoto , Ikezaki Hidekazu
Published: July 2013

Objectives

The purpose of this study was to evaluate and compare the palatability of 10 formulations (the original manufacturer's formulation and nine generics) of amlodipine orally disintegrating tablets (ODTs) by means of human gustatory sensation testing, disintegration/dissolution testing and the evaluation of bitterness intensity using a taste sensor.

Methods

Initially, the palatability, dissolution and bitterness intensity of the ODTs were evaluated in gustatory sensation tests. Second, the disintegration times of the ODTs were measured using the OD-mate, a newly developed apparatus for measuring the disintegration of ODTs, and lastly, the bitterness intensities were evaluated using an artificial taste sensor.

Key findings

Using factor analysis, the factors most affecting the palatability of amlodipine ODTs were found to be disintegration and taste. There was high correlation between the disintegration times of the 10 amlodipine ODTs estimated in human gustatory testing and those found using the OD-mate. The bitterness intensities of amlodipine ODTs 10, 20 and 30 s after starting the conventional brief dissolution test and the values determined by the taste sensor were highly correlated with the bitterness intensities determined in gustatory sensation testing.

Conclusions

The OD-mate and the taste sensor may be useful for predicting the disintegration and bitterness intensity of amlodipine ODTs in the mouth.
CAG Repeat Testing of Androgen Receptor Polymorphism: Is This Necessary for the Best Clinical Management of Hypogonadism?
Authors: Francomano Davide , Greco Emanuela A. , Lenzi Andrea , Aversa Antonio
Published: July 2013

Introduction

It is controversial whether or not testing the length of the androgen receptor polymorphism in clinical practice is useful for correct diagnosis and treatment of hypogonadism.

Aim

To describe the molecular and clinical implications of testing the length of the androgen receptor polymorphism for treatment of hypogonadism in both male and female subjects.

Methods

A systematic Medline search was conducted using several terms related to and including the terms “androgen receptor,” “CAG-repeat polymorphism,” “male hypogonadism,” “female hypogonadism,” and “neurodegenerative disease.”

Main Outcome Measures

Clinical evidence that demonstrates the importance of CAG repeat number investigation in male and female hypogonadism.

Results

A thorough review of the clinical utility of CAG repeat polymorphism investigation in men and women with hypogonadism is presented.

Conclusions

The role of AR CAG repeat number investigation in hypogonadism (male and female) is not yet established in the clinical practice. In both sexes, a role during clinical management of hormonal replacement therapies may be hypothesized, but the CAG repeat number's relationship with the presence or absence of hypogonadal symptoms remains unclear. Pharmacogenomic investigations of the AR polymorphism may be a future option to tailor testosterone titration individually and to better identify subjects as potentially more or less responsive to treatments; also, investigation may be important to individually predict beneficial and side effects in special subpopulations, specifically, obese men and postmenopausal women.
Calling Democracies and Dictatorships: The Effect of Political Regime on International Long‐Distance Rates
Authors: Holkeboer Christian Bachelder , Vreeland James Raymond
Published: July 2013

Do political regimes systematically impact the price of international long‐distance phone calls? We argue that, compared to autocracies, democratic governments have stronger incentives to regulate the provision of telephone service efficiently. In contrast, autocracies have incentives to limit communication between their citizens and the rest of the world. We thus expect the price of international long‐distance to vary with political regime. Controlling for other factors that may impact long‐distance pricing – such as level of economic development – we test this hypothesis using a cross‐section of 190 countries and find evidence of a democracy‐discount. It costs less to call democracies by about 25 percent.
Impact of trematodes on the population structure and shell shape of the estuarine mud snail Hydrobia ulvae from a Southern European estuary
Authors: Bordalo Maria D. , Ferreira Susana M. F. , Jensen Kurt T. , Pardal Miguel A.
Published: July 2013

The occurrence of trematodes within the gastropod Hydrobia ulvae was studied in two areas (a Zostera noltii bed and a eutrophic area) in the Mondego Estuary, Portugal. The aim was to assess trematode infections across snail age classes, as well as to investigate any influence of parasitism on the shell shape and size of these gastropods. In the Z. noltii bed, infection occurred in snails with shell height of 1.5–6 mm, but a higher prevalence was seen in intermediate size classes (3–5 mm). Infected individuals were never found among the elder gastropods. In the eutrophic area, infection was commonly observed within small individuals (1.6–2.5 mm), as large individuals were rarely found. The warm temperate climate in this coastal system may cause infected specimens to die before they can grow to larger dimensions, in contrast to Northern European populations. The frequency of snails with thin, distorted and corroded shells was higher among infected than non‐infected snails. Infected individuals were frequently colonized by epibionts that may have additional detrimental effects and probably promote shell erosion. Infection with trematodes and their influence on snail size needs consideration in the evaluation of parameters related to population dynamics and population structure. If the implications of parasite infection are ignored, inadequate decisions about ecosystem management may be taken, resulting mainly from erroneous assessment of population structure, age composition and ecological longevity. The role of parasites is especially important to consider for systems under environmental stress.
Distribution of iron on Vesta
Authors: Yamashita N. , Prettyman T. H. , Mittlefehldt D. W. , Toplis M. J. , McCoy T. J. , Beck A. W. , Reedy R. C. , Feldman W. C. , Lawrence D. J. , Peplowski P. N. , Forni O. , Mizzon H. , Raymond C. A. , Russell C. T.
Published: July 2013

We have completed a mapping study of 7.6 MeV gamma rays produced by neutron capture by Fe at the surface of the main belt asteroid 4 Vesta as measured by the bismuth germanate scintillator of the Gamma Ray and Neutron Detector (GRaND) on the Dawn spacecraft. The procedures used to determine Fe counting rates are presented, along with a global map, constituting the necessary initial step to quantify Fe abundances. While the final calibration of orbital data to absolute concentrations has not been determined, the range of fully corrected Fe counting rates is compared with that of Fe in howardites. We find that the global distribution of corrected Fe counting rates is generally consistent with mineralogy and composition determined independently by other instruments on the Dawn spacecraft, including measurements of pyroxene absorption bands by the Visible and Infrared Spectrometer and Framing Camera, and an index of diogenitic materials provided by neutron absorption measurements by GRaND. In addition, there is a distinctive low Fe region in the western hemisphere that was not reported by reflectance or optical observations, possibly indicating the presence of a cumulate eucrite component in Vesta's regolith.
Evidence for a recent horizontal transmission and spatial spread ofWolbachiafrom endemicRhagoletis cerasi(Diptera:Tephritidae) to invasiveRhagoletis cingulatainEurope
Authors: Schuler Hannes , Bertheau Coralie , Egan Scott P. , Feder Jeffrey L. , Riegler Markus , Schlick‐Steiner Birgit C. , Steiner Florian M. , Johannesen Jes , Kern Peter , Tuba Katalin , Lakatos Ferenc , Köppler Kirsten , Arthofer Wolfgang , Stauffer Christian
Published: July 2013

The widespread occurrence ofWolbachiain arthropods and nematodes suggests that this intracellular, maternally inherited endosymbiont has the ability to cross species boundaries. However, direct evidence for such a horizontal transmission ofWolbachiain nature is scarce. Here, we compare the well‐characterizedWolbachiainfection of theEuropean cherry fruit fly,Rhagoletis cerasi, with that of theNorthAmerican eastern cherry fruit fly,Rhagoletis cingulata, recently introduced toEurope. Molecular genetic analysis ofWolbachiabased on multilocus sequence typing and theWolbachiasurface proteinwspshowed that allR. cingulataindividuals are infected withwCin2 identical towCer2 inR. cerasi. In contrast,wCin1, a strain identical towCer1 inR. cerasi, was present in severalEuropean populations ofR. cingulata, but not in any individual from theUnitedStates. Surveys ofR. cingulatafromGermany andHungary indicated that in some populations, the frequency ofwCin1 increased significantly in just a few years with at least two independent horizontal transmission events. This is corroborated by the analysis of the mitochondrial cytochrome oxidase II gene that showed association ofwCin1 with two distinct haplotypes inGermany, one of which is also infected withwCin1 inHungary. In summary, our study provides strong evidence for a very recent inter‐specificWolbachiatransmission with a subsequent spatial spread in field populations.
Population genomics of a symbiont in the early stages of a pest invasion
Authors: Brown Amanda M. V. , Huynh Lynn Y. , Bolender Caitlin M. , Nelson Kelly G. , McCutcheon John P.
Published: July 2013

Invasive species often depend on microbial symbionts, but few studies have examined the evolutionary dynamics of symbionts during the early stages of an invasion. The insect Megacopta cribraria and its bacterial nutritional symbiont Candidatus Ishikawaella capsulata invaded the southeastern US in 2009. While M. cribraria was initially discovered on wild kudzu plants, it was found as a pest on soybeans within 1 year of infestation. Because prior research suggests Ishikawaella confers the pest status—that is, the ability to thrive on soybeans—in some Megacopta species, we performed a genomic study on Ishikawaella from US. Megacopta cribraria populations to understand the role of the symbiont in driving host plant preferences. We included Ishikawaella samples collected in the first days of the invasion in 2009 and from 23 locations across the insect's 2011 US range. The 0.75 Mb symbiont genome revealed only 47 fixed differences from the pest‐conferring Ishikawaella in Japan, with only one amino acid change in a nutrition‐provisioning gene. This similarity, along with a lack of fixed substitutions in the US symbiont population, indicates that Ishikawella likely arrived in the US capable of being a soybean pest. Analyses of allele frequency changes between 2009 and 2011 uncover signatures of both positive and negative selection and suggest that symbionts on soybeans and kudzu experience differential selection for genes related to nutrient provisioning. Our data reveal the evolutionary trajectory of an important insect‐bacteria symbiosis in the early stages of an invasion, highlighting the role microbial symbionts may play in the spread of invasive species.
White matter pathology and disconnection in the frontal lobe in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)
Authors: Craggs Lucinda J. L. , Yamamoto Yumi , Ihara Masafumi , Fenwick Richard , Burke Matthew , Oakley Arthur E. , Roeber Sigrun , Duering Marco , Kretzschmar Hans , Kalaria Raj N.
Published: July 2013

Background

Magnetic resonance imaging indicates diffuse white matter (WM) changes are associated with cognitive impairment in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). We examined whether the distribution of axonal abnormalities is related to microvascular pathology in the underlying WM.

Methods

We used post‐mortem brains from CADASIL subjects and similar age cognitively normal controls to examine WM axonal changes, microvascular pathology, and glial reaction in up to 16 different regions extending rostro‐caudally through the cerebrum. Using unbiased stereological methods, we estimated length densities of affected axons immunostained with neurofilament antibody SMI32. Standard immunohistochemistry was used to assess amyloid precursor protein immunoreactivity per WM area. To relate WM changes to microvascular pathology, we also determined the sclerotic index (SI) in WM arterioles.

Results

The degree of WM pathology consistently scored higher across all brain regions in CADASIL subjects (P < 0.01) with the WM underlying the primary motor cortex exhibiting the most severe change. SMI32 immunoreactive axons in CADASIL were invariably increased compared with controls (P < 0.01), with most prominent axonal abnormalities observed in the frontal WM (P < 0.05). The SIs of arterioles in CADASIL were increased by 25–45% throughout the regions assessed, with the highest change in the mid‐frontal region (P = 0.000).

Conclusions

Our results suggest disruption of either cortico‐cortical or subcortical‐cortical networks in the WM of the frontal lobe that may explain motor deficits and executive dysfunction in CADASIL. Widespread WM axonal changes arise from differential stenosis and sclerosis of arterioles in the WM of CADASIL subjects, possibly affecting some axons of projection neurones connecting to targets in the subcortical structures.
Data quality of the Australia and New Zealand Dialysis and Transplant Registry: A pilot audit
Authors: Gray Nicholas A , Mahadevan Kumar , Campbell Victoria K , Noble Euan P , Anstey Chris M
Published: July 2013

Aim

Most clinical registries in Australia, including the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA), do not audit submitted data. Inaccurate data can bias registry analysis. This study aimed to audit data submitted to ANZDATA from a single region.

Methods

A retrospective audit of individual haemodialysis patient data recorded by ANZDATA at 31 December 2009 was completed by nephrologists in a blinded fashion. Original data were recorded by nursing staff. Patients received treatment at a public hospital, two affiliated satellite haemodialysis units, and three private haemodialysis units.

Results

Fifty‐one audits were completed of a total 175 patients (29.1%) undertaking haemodialysis in 2009. Primary renal disease was correct in 86.3% (95%CI: 74.3–93.2), although errors in type of glomerulonephritis were common. Date of first dialysis (± 1‐month error margin) was correct for 93.6%. Creatinine at first dialysis (± 10% error margin) was correct in 74.4%. Baseline comorbidity accuracy included: peripheral vascular disease (sensitivity 36.4% (95%CI: 24.6–50.1), specificity 82.8% (95%CI: 70.2–90.7)), ischaemic heart disease (sensitivity 69.2% (95%CI: 55.6–80.2), specificity 88.0% (95%CI: 76.3–94.3)), chronic lung disease (sensitivity 25.0% (95%CI: 15.2–38.3), specificity 93.6% (95%CI: 83.4–97.7)), diabetes (sensitivity 86.4% (95%CI: 74.4–93.2), specificity 96.6% (95%CI: 87.5–99.1)), cerebrovascular disease (sensitivity 75.0% (95%CI: 61.7–84.8), specificity 95.3% (95%CI: 85.8–98.6)), and ever smoked (sensitivity 83.3% (95%CI: 70.3–91.4), specificity 71.4% (95%CI: 57.3–82.3)). Non‐melanoma skin cancer was under‐reported and inaccurate.

Conclusion

Data accuracy was favourable compared with other renal registry validation studies. Data accuracy may be improved by education and training of collectors. A larger audit is necessary to validate ANZDATA.
The views of stakeholders on the role of the primary school in preventing childhood obesity: a qualitative systematic review
Authors: Clarke J. , Fletcher B. , Lancashire E. , Pallan M. , Adab P.
Published: July 2013

Schools are increasingly recognized as an ideal setting for interventions to tackle childhood obesity. A better understanding of the views of key stakeholders would help to engage schools and inform the feasibility of such interventions in practice. This meta‐synthesis of 18 qualitative studies explores the views of parents, school staff, school governors, school nurses and students on the role of the primary school in preventing childhood obesity. Six categories emerged: ‘School as a key setting’; ‘What schools should be doing to promote healthy eating (HE)’; ‘What schools should be doing to promote physical activity (PA)’; ‘General barriers’; ‘Barriers to promoting HE at school’; and ‘Barriers to promoting PA at school’. Thirty‐seven finer‐level themes emerged within these categories. Stakeholders agreed on the key role of the primary school as a setting for obesity prevention, the importance of schools providing and promoting opportunities for HE and PA, and the need for schools to work with parents. Some perceived barriers could be overcome at school level, e.g. using unhealthy foods as rewards/fundraisers or withholding PA for bad behaviour. Leadership and guidance from government were considered to be needed to counteract other observed barriers, particularly regarding school canteens, support for parents and time for PA.
Incidence of osteoradionecrosis following oral and maxillofacial surgery in irradiated head and neck cancer patients
Authors: de Menezes B.C. , de Souza Noronha V.R.A. , Carvalho A.L. , da Silva Freire A.R. , Jham B.C.
Published: July 2013

Aim

The aim of this study was to investigate the incidence of osteoradionecrosis following various surgical procedures, including tooth extraction, periodontal surgery, pre‐prosthetic surgery, removal of bone spicules and removal of bone reconstruction/osteosynthesis plates.

Material and methods

The charts of 68 patients who had undergone post‐radiotherapy surgical procedures were reviewed. The following information was obtained: gender, age, radiotherapy dose and field, type of surgical procedure and time between the end of radiotherapy and the surgical procedure.

Results

Osteoradionecrosis developed in 14 patients and did not statistically correlate with gender, radiotherapy dose and field or time between the end of radiotherapy and the surgical procedure. Removal of bone spicules was significantly associated with osteoradionecrosis (P = 0.033), compared with tooth extraction, pre‐prosthetic surgery, removal of reconstruction/osteosynthesis plates and periodontal surgery.

Conclusions

Our findings show removal of bone spicules is a significant risk factor for the development of osteoradionecrosis, suggesting that careful evaluation and management of spicules in previously irradiated patients is particularly important in the prevention of osteoradionecrosis.
Multiple benign tumours in the oral and maxillofacial region of an adolescent
Authors: Jeganathan S. , Gerber B. , Curtis A. , Saeed N.
Published: July 2013

Multiple tumours occurring in the oral and maxillofacial region of paediatric patients are extremely rare. This case report describes the successful management of the first documented case of synchronous pleomorphic adenoma of the submandibular gland and Schwannoma of the tongue in a 16‐year‐old girl.
An unusual case of an inverted and impacted maxillary third molar
Authors: Rammal M. , Alfonso C.
Published: July 2013

Inverted and impacted maxillary third molars are an uncommon dental anomaly. The purpose of this case report is to present a rare case of an inverted maxillary third molar whose anatomical position was localised by a panoramic radiograph near the alveolar lobe of the maxillary sinus and the zygomatic process of the maxilla.
Cortical processing of simultaneous hand and foot movements: Evidence from event‐related potentials
Authors: Miller Jeff , Gerstner Natascha
Published: July 2013

The motor processes involved in generating simultaneous hand and foot movements were studied by recording event‐related potentials (ERPs) during reaction time tasks in which participants made hand and foot movements either alone or in combination with one another. In particular, we assessed whether the motor potentials generated during combined movements were simply superpositions of the potentials generated during the individual movements in isolation. ERPs generated during single‐limb movements replicated previously observed motor potentials, and those generated during both the execution (Experiment 1) and preparation (Experiment 2) of combined movements showed some deviations from the predictions of the superposition hypothesis, suggesting the presence of neural interactions between the hand and foot movement systems during preparation and execution of these actions.
Different Glycosylation Pattern of Human IgG1 and IgG3 Antibodies Isolated From Transiently as Well as Permanently Transfected Cell Lines
Authors: Vestrheim A. C. , Moen A. , Egge‐Jacobsen W. , Bratlie D. B. , Michaelsen T. E.
Published: July 2013

The effector functions of IgG depend on the presence of carbohydrates attached to asparagine 297 in the Fc portion. In this report, glycosylation profiles of recombinant wild‐type and mutant IgG1 and IgG3 antibodies produced from three cell lines were analysed using LC‐ESI‐Orbitrap. Differences were detected between IgG1 and IgG3, where IgG1 generally contained fucosylated glycoforms, while IgG3 showed a noticeable percentage of non‐fucosylated glycoforms. When using NS‐0 and J558L cells for permanent transfection, IgG1 wt glycoforms differed between the two cell lines, while IgG3 wt glycoforms did not. Transiently transfected HEK 293E cells were used to produce IgG1 and IgG3 wt and mutants, affecting complement activation. Cell supernatants were harvested at early and late time points and analysed separately. IgG's harvested late showed simpler and less developed glycosylation structure compared with those harvested early. IgG's harvested early were slightly more effective in complement activation than those harvested late, while the antibody‐dependent cell‐mediated cytotoxicity was unaltered. Generally, the glycosylation pattern of the mutants tested, including a hinge truncate mutant of IgG3, did not differ significantly from the wild‐type IgG's. The difference in glycosylation pattern of IgG1 compared with IgG3 therefore appears not to be due to the long hinge region of IgG3 (62 amino acids) relative to the IgG1 hinge region (15 amino acids). Furthermore, mutation variants at or near the C1q‐binding site showed similar glycosylation structure and difference in their complement activation activity observed earlier is thus most likely due to differences in protein structure only.
The Effects of Organizational Characteristics and State Environmental Policies on Sulfur‐Dioxide Pollution in U.S. Electrical Energy Corporations
Authors: Prechel Harland , Touche George
Published: July 2013

Objective

This article examines the effects of organizational characteristics of parent companies in the electrical energy industry and state environmental policies on environmental pollution. By focusing on parent companies, the study draws attention to the managers who have the authority to make decisions that affect environmental pollution.

Methods

The study employs a cross‐sectional ordinary least squares regression design to examine three measurements of the dependent variable, SO2 emission rates.

Results

While controlling for several potential effects, the findings support all four hypotheses, which maintain that greater structural complexity, profits, dividend payments to increase shareholder value, and lower state‐level environmental standards resulted in greater environmental pollution.

Conclusions

The findings suggest that policymakers should focus on capital allocation decisions in parent companies and reexamine the neofederalist policies that provided states with greater autonomy for environmental regulation of corporations in the electrical energy sector.
Feature Inheritance, vP Phases and the Information Structure of Small Clauses
Authors: Jiménez‐Fernández Ángel L. , Spyropoulos Vassilios
Published: July 2013

In this paper we explore the interaction of discourse properties in the syntax of small clauses from a cross‐linguistic perspective. In line with Chomsky's (,) idea that phasal properties should be extended to all phases, we argue for a strict parallelism between C‐T andv‐V, suggesting thatventers the derivation with both agreement and discourse features. These features may be inherited by V depending on the relevant language. Building on Miyagawa () and Jiménez‐Fernández (), we claim that in Spanish and Greek, in contrast with English, both agreement and discourse features are inherited by V. This strategy accounts for the different order rearrangements detected in small clauses. The proposal can easily be extended to other languages such as Italian, Serbo‐Croatian, Russian and Ukrainian, as opposed to French, Norwegian, Afrikaans and German.
Molecular phylogeny, evolution and classification of the Hydrophilidae (Coleoptera)
Authors: SHORT ANDREW EDWARD Z. , FIKÁČEK MARTIN
Published: July 2013

The phylogeny and evolutionary history of the water scavenger beetles (Coleoptera: Hydrophilidae) are inferred from comprehensive analyses of DNA sequence data from the mitochondrial genes COI, COII and 16S and the nuclear genes 18S, 28S and arginine kinase. Bayesian and maximum parsimony analyses included 151 taxa, representing all subfamilies, tribes and subtribes that have ever been proposed in the family, as well as representatives of the hydrophiloid families Helophoridae, Hydrochidae, Spercheidae, Epimetopidae and Georissidae. The resulting well‐supported trees strongly disagree with prior classifications of the Hydrophilidae, suggesting that the smaller subfamilies (Horelophinae, Horelophopsinae and Sphaeridiinae) are derived from within the larger Hydrophilinae. The existing tribal classification is more compatible with our results, but many significant differences are evident. Here, we present a new classification of the Hydrophilidae comprising 6 subfamilies and 12 tribes. Each subfamily and tribe is reviewed in detail with (i) a morphological diagnosis, including known or putative morphological synapomorphies, (ii) its taxonomic circumscription, including genera not included in our analyses, and (iii) a review of its general biology and geographic distribution. A new identification key to subfamily and tribe based on adult morphology is also provided. The newly adopted classification requires the following taxonomic changes: the subfamily Hydrophilinae sensu n. is redefined to include only the tribes Amphiopini stat.n. (removed from the synonymy with the Chaetarthriini), Berosini, Laccobiini, Hydrophilini and Hydrobiusini (= Sperchopsini syn.n.); the subfamily Chaetarthriinae stat.n. is removed from synonymy with the Hydrophilinae and includes the tribes Chaetarthriini and Anacaenini (= Horelophinae syn.n.); the Acidocerinae stat.n. (= Horelophopsinae syn.n.) and Rygmodinae stat.n. (= Andotypini syn.n., Borborophorini syn.n. and Tormissini syn.n.) are elevated to subfamily rank; and the subfamily Enochrinae subfam.n. is established for the genus Enochrus and its relatives. The implications for the morphological evolution, ecological transitions and biogeography of the family are discussed.
Spatiotemporal Characterization of Extracellular Matrix Microstructures in Engineered Tissue: A Whole-Field Spectroscopic Imaging Approach
Authors: Xu Zhengbin , Ozcelikkale Altug , Kim Young L. , Han Bumsoo
Published: July 2013

Quality and functionality of engineered tissues are closely related to the microstructures and integrity of their extracellular matrix (ECM). However, currently available methods for characterizing ECM structures are often labor-intensive, destructive, and limited to a small fraction of the total area. These methods are also inappropriate for assessing temporal variations in ECM structures. In this study, to overcome these limitations and challenges, we propose an elastic light scattering approach to spatiotemporally assess ECM microstructures in a relatively large area in a nondestructive manner. To demonstrate its feasibility, we analyze spectroscopic imaging data obtained from acellular collagen scaffolds and dermal equivalents as model ECM structures. For spatial characterization, acellular scaffolds are examined after a freeze/thaw process mimicking a cryopreservation procedure to quantify freezing-induced structural changes in the collagen matrix. We further analyze spatial and temporal changes in ECM structures during cell-driven compaction in dermal equivalents. The results show that spectral dependence of light elastically backscattered from engineered tissue is sensitively associated with alterations in ECM microstructures. In particular, a spectral decay rate over the wavelength can serve as an indicator for the pore size changes in ECM structures, which are at nanometer scale. A decrease in the spectral decay rate suggests enlarged pore sizes of ECM structures. The combination of this approach with a whole-field imaging platform further allows visualization of spatial heterogeneity of EMC microstructures in engineered tissues. This demonstrates the feasibility of the proposed method that nano- and micrometer scale alteration of the ECM structure can be detected and visualized at a whole-field level. Thus, we envision that this spectroscopic imaging approach could potentially serve as an effective characterization tool to nondestructively, accurately, and rapidly quantify ECM microstructures in engineered tissue in a large area.
Development of Gas Turbine Combustion Tuning Technology Using Six Sigma Tools
Authors: Lee Min Chul , Ahn Kwang Ick , Yoon Youngbin
Published: July 2013

A conventional combustion tuning method for a gas turbine needs more than 24 hours with lots of human labor. In addition it is hard to certify whether the plant is optimized because the conventional tuning is based on human decisions and subjective empirical data over a long time. In this study we developed a combustion tuning technology using six sigma tools (CTSS) to effectively meet the increasingly stringent NOx regulations and to save combustion tuning time. CTSS was conducted in five steps—define-identify-design-optimize-verify (DIDOV). First, the NOx reduction target was defined (Step 1, define), the current status of the plant was diagnosed (Step 2, identify), and the vital few control parameters to achieve the defined target were determined by analyzing the correlation between the control parameters and NOx emissions (Step 3, design). For the next step, the optimum condition was derived from one of the six sigma tools (Step 4, optimize), and finally the optimum condition was verified by applying the condition to the gas turbine combustion (Step 5, verify). As a result of CTSS, averaged NOx emissions were reduced by more than 70% and the standard deviation was improved by more than 60%. These results show that CTSS is a potential tool for enhanced reliability of plant operations and scientific method for quick and exact combustion tuning.
Plasma Actuation Control of Boundary Layer Flashback in Lean Premixed Combustor
Authors: Versailles Philippe , Chishty Wajid Ali , Vo Huu Duc
Published: July 2013

Dry low emissions premixed combustion systems have the ability to give larger NOx emissions reduction in comparison to diffusion type of combustors. However, these systems are prone to flashback because the fuel and oxidizers are mixed upstream of the combustion chamber. This is particularly true for premixed systems burning high-reactivity fuels due to their higher flame speed. Flashback is undesirable in gas turbines because it leads to overheating and failure of fuel nozzles and premixing sections. Recently, a novel application of Plasma Actuation through non-thermal Dielectric Barrier Discharge has been shown to significantly delay flashback in the core flow along the axis of the premixer. Building on this successful endeavour, efforts were directed to prove the effectiveness of the control method in situations where flashback was triggered in the boundary layer. Results show that the current application delays the occurrence of flashback in the boundary layer of the premixer to higher equivalence ratios. Improvements in the combustor operability margin of 10 to 14% when burning natural gas-air mixtures, and of about 3.5% when replacing the fuel by an equimolar mixture of natural gas and hydrogen, were achieved. It was found that the proposed application of plasma actuation is even more efficient in preventing flashback in the boundary layer than in the core flow.
Obtaining Bifurcation Diagrams With a Thermoacoustic Network Model
Authors: Campa Giovanni , Juniper Matthew P.
Published: July 2013

Linear techniques can predict whether the non-oscillating (steady) state of a thermoacoustic system is stable or unstable. With a sufficiently large impulse, however, a thermoacoustic system can reach a stable oscillating state even when the steady state is also stable. A nonlinear analysis is required to predict the existence of this oscillating state. Continuation methods are often used for this but they are computationally expensive.

In this paper, an acoustic network code called LOTAN is used to obtain the steady and the oscillating solutions for a horizontal Rijke tube. The heat release is modelled as a nonlinear function of the mass flow rate. Several test cases from the literature are analysed in order to investigate the effect of various nonlinear terms in the flame model. The results agree well with the literature, showing that LOTAN can be used to map the steady and oscillating solutions as a function of the control parameters. Furthermore, the nature of the bifurcation between steady and oscillating states can be predicted directly from the nonlinear terms inside the flame model.
Flame Leading Edge and Flow Dynamics in a Swirling, Lifted Flame
Authors: Malanoski Michael , Aguilar Michael , O’Connor Jacqueline , Shin Dong-hyuk , Noble Bobby , Lieuwen Tim
Published: July 2013

Flames in high swirl flow fields with vortex breakdown often stabilize aerodynamically in front of interior flow stagnation points. In contrast to shear layer stabilized flames with a nearly fixed, well defined flame attachment point, the leading edge of aerodynamically stabilized flames can move around substantially, due to both the inherent dynamics of the vortex breakdown region, as well as externally imposed oscillations. Motion of this flame stabilization point relative to the flow field has an important dynamical role during combustion instabilities, as it creates flame front wrinkles and heat release fluctuations. For example, a prior study has shown that nonlinear dynamics of the flame response at high forcing amplitudes were related to these leading edge dynamics. This heat release mechanism exists alongside other flame wrinkling processes, arising from such processes as shear layer rollup and swirl fluctuations.

This paper describes an experimental investigation of acoustic forcing effects on the dynamics of leading edge of a swirl stabilized flame. Vortex breakdown bubble dynamics were characterized using both high-speed particle image velocimetry (PIV) and line-of-sight high-speed CH* chemiluminescence. A wide array of forcing conditions was achieved by varying forcing frequency, amplitude, and acoustic field symmetry. These results show significant differences in instantaneous and time averaged location of the flow stagnation points. They also show motion of the flame leading edge that are of the same order of magnitude as corresponding particle displacement associated with the fluctuating velocity field. This observation suggests that heat release fluctuations associated with leading edge motion may be just as significant in controlling the unsteady flame response as the flame wrinkles excited by velocity fluctuations.
Large Eddy Simulation/Eulerian Probability Density Function Approach for Simulating Hydrogen-Enriched Gas Turbine Combustors
Authors: Lietz Christopher , Donde Pratik , Raman Venkat , Martin Scott
Published: July 2013

To describe partially-premixed combustion inside hydrogen-rich combustors, a novel quadrature-based probability density function (PDF) approach is studied here. The PDF approach is comprehensive in describing multiple combustion regimes, and multiple inlet streams. The methodology is implemented in the context of the large eddy simulation (LES) approach. The main bottleneck in utilizing the PDF approach is that the PDF transport equation, which needs to be evolved along with the LES equations, is high-dimensional and intractable using conventional discretization techniques. In order to ensure that the PDF approach is easily transferred to existing industrial flow solvers, a quadrature-based Eulerian method for solving the PDF transport equation is considered here. The corresponding Eulerian equations are implemented in the open source OpenFOAM code using an unstructured grid system. Simulations of an experimental high-pressure combustor demonstrate that the PDF approach significantly changes the reaction structure compared to laminar chemistry assumption.
Development and Implementation of the AEV Burner for the Alstom GT13E2
Authors: Zajadatz Martin , Pennell Douglas , Bernero Stefano , Paikert Bettina , Zoli Raffaele , Döbbeling Klaus
Published: July 2013

Increasing public awareness and more stringent legislation on pollutants drive gas turbine manufacturers to develop combustion systems with low NOx emissions. In combination to this demand the gas turbines have to provide a broad range of operational flexibility to cover variations in gas composition and ambient conditions as well as varying daily and seasonal energy demands and load profiles.

This paper describes the development and implementation of the Alstom AEV (Advanced EnVironmental) burner, an evolution of the EV. Continuous fuel supply to two fuel stages at any engine load simplifies the operation and provides a fast and reliable response of the combustion system during transient operation of the gas turbine. Increased turndown with low emissions is an additional advantage of the combustion system upgrade.
Combustion Dynamics Diagnostics and Mitigation on a Prototype Gas Turbine Combustor
Authors: Mohammad Bassam S. , Balasubramanyam Preetham , McManus Keith , Ruszczyk Jeffrey , Elkady Ahmed M. , Mueller Mark A.
Published: July 2013

Combustion dynamics have detrimental effects on hardware durability as well as combustor performance and emissions. This paper presents a detailed study on the impact of combustion dynamics on NOx and CO emissions generated from a prototype gas turbine combustor operating at a pressure of 180 psia (12.2 bars) with a pre-heat temperature of 720 F (655.3 K) (E-class machine operating conditions). Two unstable modes are discussed. The first is an intermittent mode, at 750 Hz, that emerges at flame temperatures near 2900°F (1866.5 K), resulting in high NOx and CO emissions. With increasing fuel flow, NOx and CO emissions continue to increase until the flame temperature reaches approximately 3250°F (2061 K), at which point the second acoustic mode begins to dominate. Flame images indicate that the intermittent mode is associated with flame motion which induces the high NOx and CO emissions. The second mode is also a 750 Hz, but of constant amplitude (no intermittency). Operation in this second 750 Hz mode results in significantly reduced NOx and CO emissions. At pressures higher than 180 psia (12.2 bars), the intermittent mode intensifies, leading to flashback at flame temperatures above 2850°F (1839 K). In order to mitigate the intermittent mode, a second configuration of the combustor included an exit area restriction. The exit area restriction eliminated the intermittent mode, resulting in stable operation and low emissions over a temperature range of 2700–3200°F (1755–2033 K). A comparison of the NOx emissions, as function of flame temperature, with previous published data for perfectly premixed indicates that, while the low amplitude 750 Hz oscillations have little effect, the intermittent mode significantly increases emissions. Mode shape analysis shows that the 750 Hz instability corresponds to the 1/4 wave axial mode. In the current research a ceramic liner is used while the previous published data was collected with a quartz liner. Typically, quartz is avoided due to reductions in effective flame temperature by radiation losses. Experiments showed that NOx emissions were not affected by the combustor liner type. This agreement between the quartz and ceramic liners data indicates limited effect from the radiation heat losses on NOx emissions.
Imprinted Effusion Modeling and Dynamic CD Calculation in Gas Turbine Combustors
Authors: Rida Samir , Reynolds Robert , Chakravorty Saugata , Gupta Kapil
Published: July 2013

A practical computational fluid dynamics (CFD) approach to modeling effusion orifices in gas turbine combustor liners is proposed specifically when liner metal geometry is not included and conjugate heat transfer is not invoked. The focus is on eliminating effusion orifices from the model while maintaining the imprint of the orifices on the cold and hot sides of the liner wall. The imprinted boundaries serve as embedded mass flow inlets and outlets on both sides of the wall and maintain the integrity of the wall geometry. An empirical model is then used to extract and inject mass from the cold and hot sides of the liner, respectively. The mass extraction and injection process is performed for each orifice based on local conditions such as pressure, temperature and discharge coefficient. The discharge coefficient is, in turn, dynamically computed for each orifice based on approach angle, approach Mach number, discharge Mach number and orifice length to diameter ratio. With this approach, the fidelity of the liner wall is preserved for better heat transfer predictions and easier near wall meshing. In addition, the discharge coefficient is not assumed but calculated allowing the redeployment of inherently inadequate effusion orifice mesh cells to other critical areas of the combustor. Presented are results of two combustor cases to demonstrate the practicality and accuracy of the proposed method as compared to standard effusion modeling and their comparison with rig data.
An Experimental Investigation of Kerosene Droplet Breakup by Laser-Induced Blast Waves
Authors: Gebel Gregor C. , Mosbach Thomas , Meier Wolfgang , Aigner Manfred , Le Brun Stéphane
Published: July 2013

The work presented in this paper intends to deepen our understanding of the mechanisms involved in the spark ignition of liquid fuel sprays. An experimental study is presented regarding the ignition of monodisperse droplet chains of Jet A-1 aviation kerosene in a generic model combustor under well-defined boundary conditions. Breakdowns created by focused laser radiation were used as ignition sparks. They featured rapid spatial expansion, resulting in the formation of spherical blast waves in the surrounding air. The focus of this study lay on the effect of the blast waves on the fuel droplets. Blast wave trajectories were investigated by Schlieren imaging. Their interaction with kerosene droplets was observed by a high-speed camera via a long distance microscope; the droplets were visualized by laser-induced Mie scattering. Droplets within a distance of ten millimetres from the breakdown position were disintegrated by the aerodynamic forces of the post-shock flow field. Different breakup modes were observed, depending on the distance from the breakdown position.
Part-Load Operation of a Piloted FLOX® Combustion System
Authors: Roediger Tim , Lammel Oliver , Aigner Manfred , Beck Christian , Krebs Werner
Published: July 2013

A large operational envelope is a key requirement for modern gas turbines. Fuel staging is used here to improve the part load performance of an enhanced FLOX® type combustor. A swirl-stabilized pilot stage is integrated in the FLOX® burner and the results of high pressure lab-scale experiments at system relevant conditions are presented. The operational envelope of the piloted system could be extended by approximately 10%. Pressure scaling and variations of air preheat temperature and jet velocity describe fundamental characteristics of the piloted system. OH* chemiluminescence imaging is used to investigate flame shapes and the effect of the interacting flames. Emissions and pressure pulsations define limits, and optimum operation conditions of the combustor and show the influence of part load relevant parameters.
Non-Linear Effects in a Lean Partially Premixed Combustor During Limit Cycle Operation
Authors: Roman Casado J. C. , Kok J. B. W.
Published: July 2013

In a gas turbine combustor limit cycles of pressure oscillations may occur due to a coupling of combustion dynamics to the acoustic field inside the system. In this case, the engine is subjected to high vibrations and the possibility of structural damage.

Experimental research in this subject was carried out in a laboratory combustor operating in a lean, partially premixed methane/air flame, where the flame stabilizes on a triangular bluff body inside a rectangular combustor duct. Depending on the operating point, the flame shows a stable or unstable behavior. In this last case, amplitudes up to 155 dB (ref 20 μPa) have been recorded. The variation of behavior of the instability with operating conditions is well known. The stable combustion presents a low amplitude broadband noise. The unstable regime is more interesting. It has a main peak with high amplitude and fixed frequency and several secondary peaks at multiple times the frequency of the fundamental one. This peaks can be seen in the pressure and heat release spectrum.

The secondary peaks of the pressure spectrum are due to non-linear effects. Odd numbered peaks came from a change in the acoustic boundary conditions in the burner. The even peaks are the result of frequency doubling of the odd frequencies. The frequency doubling comes from a second order source term of the Ligthill’s analogy.