bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective elimination of neuroblastoma cells by synergistic effect of Akt kinase inhibitor and tetrathiomolybdate
Authors: Navrátilová Jarmila , Karasová Martina , Kohutková Lánová Martina , Jiráková Ludmila , Budková Zuzana , Pacherník Jiří , Šmarda Jan , Beneš Petr
Published: February 2017

Neuroblastoma is the most common extracranial solid tumour of infancy. Pathological activation of glucose consumption, glycolysis and glycolysis‐activating Akt kinase occur frequently in neuroblastoma cells, and these changes correlate with poor prognosis of patients. Therefore, several inhibitors of glucose utilization and the Akt kinase activity are in preclinical trials as potential anti‐cancer drugs. However, metabolic plasticity of cancer cells might undermine efficacy of this approach. In this work, we identified oxidative phosphorylation as compensatory mechanism preserving viability of neuroblastoma cells with inhibited glucose uptake/Akt kinase. It was oxidative phosphorylation that maintained intracellular level of ATP and proliferative capacity of these cells. The oxidative phosphorylation inhibitors (rotenone, tetrathiomolybdate) synergized with inhibitor of the Akt kinase/glucose uptake in down‐regulation of both viability of neuroblastoma cells and clonogenic potential of cells forming neuroblastoma spheroids. Interestingly, tetrathiomolybdate acted as highly specific inhibitor of oxygen consumption and activator of lactate production in neuroblastoma cells, but not in normal fibroblasts and neuronal cells. Moreover, the reducing effect of tetrathiomolybdate on cell viability and the level of ATP in the cells with inhibited Akt kinase/glucose uptake was also selective for neuroblastoma cells. Therefore, efficient elimination of neuroblastoma cells requires inhibition of both glucose uptake/Akt kinase and oxidative phosphorylation activities. The use of tetrathiomolybdate as a mitochondrial inhibitor contributes to selectivity of this combined treatment, preferentially targeting neuroblastoma cells.
Use of the low‐FODMAP diet in inflammatory bowel disease
Authors: Gibson Peter R
Published: February 2017

Irritable bowel syndrome (IBS)‐like symptoms are not uncommon in patients with quiescent inflammatory bowel disease (IBD). While gluten‐free diet is applied by patients, there are no reported interventional studies. The low‐FODMAP diet, on the other hand, has efficacy similar to that seen in patients with IBS in three unblinded or observational studies of IBD cohorts who had well‐controlled inflammatory disease and in one small randomized cross‐over study. FODMAP intake by patients with IBD is not elevated, and, in one study, fructan intakes were lower in patients with Crohn's disease than in controls. There is no clear relationship between the level of FODMAP intake and intestinal inflammation. The risk of compromising nutritional status with a restrictive diet must be seriously considered especially as under‐nutrition is already common in this patient population. The effects of FODMAPs on the gut microbiota of patients with Crohn's disease mimic that in IBS, with a balance between prebiosis from the addition of FODMAPs and loss of prebiosis from their reduction. As undernutrition is common in IBD, the use of restrictive diets should be supervised by a dietitian. Thus, low‐FODMAP diet is a viable option for IBS‐like symptoms but should be carefully supervised to mitigate risk.
Food regulations: low FODMAP labeling and communication goals
Authors: Méance Séverine , Giordano Josy , Chuang Emil , Schneider Heinrich
Published: February 2017

There is growing clinical evidence in support of a diet for irritable bowel syndrome (IBS) that is low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP). This low FODMAP diet is gaining acceptance globally among clinicians and IBS sufferers alike. However, there is disparity concerning the success rates of the FODMAP diet between patients, which can be attributed to differences in the recommended diet itself and to adherence issues. To address the differences in the diet, a generally accepted science‐based definition of the analytical criteria for low FODMAP products suitable for a low FODMAP diet should be developed. To address the adherence challenge, regulators should permit manufacturers of low FODMAP products to communicate the benefits of a low FODMAP diet on product labels and promotional material which will facilitate people with IBS' selection and use low FODMAP foods.
What is gluten?
Authors: Biesiekierski Jessica R
Published: February 2017

Gluten is the main storage protein of wheat grains. Gluten is a complex mixture of hundreds of related but distinct proteins, mainly gliadin and glutenin. Similar storage proteins exist as secalin in rye, hordein in barley, and avenins in oats and are collectively referred to as “gluten.” The objective was to discuss the biochemical and functional properties of the gluten proteins, including structure, sources, and dietary intakes. Literature was reviewed from food science and nutrition journals. The gluten protein networks vary because of different components and sizes, and variability caused by genotype, growing conditions, and technological processes. The structures and interactions of this matrix contribute to the unique properties of gluten. The resulting functions are essential to determining the dough quality of bread and other baked products. Gluten is heat stable and has the capacity to act as a binding and extending agent and is commonly used as an additive in processed foods for improved texture, moisture retention, and flavor. Gliadin contains peptide sequences that are highly resistant to gastric, pancreatic, and intestinal proteolytic digestion in the gastrointestinal tract. The average daily gluten intake in a Western diet is thought to be 5–20 g/day and has been implicated in several disorders. Gluten containing grains (wheat, rye, barley, and oats) are important staple foods. Gluten is among the most complex protein networks and plays a key role in determining the rheological dough properties.
Cross‐cultural and psychological issues in irritable bowel syndrome
Authors: Sahoo Swapnajeet , Padhy Susanta Kumar
Published: February 2017

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders encountered by gastroenterologists worldwide. Of all the etiological factors that had been postulated to explain the pathophysiology of IBS, cultural and psychological factors are unique and difficult to understand. Culture plays an important role in coloring the presentation of IBS, and many a times, it has a significant role in several treatment aspects too. Psychological aspects like personality profiles, family relationships, societal myths, and abuse in any form are equally important in the management perspectives of IBS. In this brief review, we had tried to specifically focus on these aspects in IBS and have explained the evidences in favor of these factors. Knowledge about various cross‐cultural aspects and psychological factors in patients with IBS is essential for taking an appropriate history and for undertaking a holistic approach for the management of the same. A collaborative team effort by psychiatrists and gastroenterologists could help in reducing the burden of this difficult to treat functional bowel disorder.
Effect of weather on temporal pain patterns in patients with temporomandibular disorders and migraine
Authors: Cioffi I. , Farella M. , Chiodini P. , Ammendola L. , Capuozzo R. , Klain C. , Vollaro S. , Michelotti A.
Published: February 2017

Patients with masticatory muscle pain and migraine typically report that the intensity of pain fluctuates over time and is affected by weather changes. Weather variables, such as ambient temperature and humidity, may vary significantly depending on whether the individual is outdoor or indoor. It is, therefore, important to assess these variables at the individual level using portable monitors, during everyday life. This study aimed to determine and compare the temporal patterns of pain in individuals affected with facial and head pain and to investigate its relation with weather changes. Eleven patients (27·3 ± 7·4 years) with chronic masticatory muscle pain (MP) and twenty (33·1 ± 8·7 years) with migraine headache (MH) were asked to report their current pain level on a visual analogue scale (VAS) every hour over fourteen consecutive days. The VAS scores were collected using portable data‐loggers, which were also used to record temperature, atmospheric pressure and relative humidity. VAS scores varied markedly over time in both groups. Pain VAS scores fluctuate less in the MP group than in the MH group, but their mean, minimum and maximum values were higher than those of migraine patients (all P < 0·05). Pain scores <2 cm were more common in the MH than in the MP group (P < 0·001). Perceived intensity of pain was negatively associated with atmospheric pressure in the MP group and positively associated with temperature and atmospheric in the MH group.

Our results reveal that patients with masticatory muscle pain and patients with migraine present typical temporal pain patterns that are influenced in a different way by weather changes.
Early Detection and Treatment of Atrial Arrhythmias Alleviates the Arrhythmic Burden in Paced Patients: The SETAM Study
Authors: AMARA WALID , MONTAGNIER CHRISTIAN , CHEGGOUR SAÏDA , BOURSIER MICHEL , GULLY CLAUDE , BARNAY CLAUDE , GEORGER FREDERIC , DEPLAGNE ANTOINE , FROMENTIN STEPHANE , MLOTEK MARCIN , LAZARUS ARNAUD , TAÏEB JERÔME ,   on behalf of the SETAM Investigators
Published: February 2017

Background

Remote monitoring (RM) can remotely detect atrial tachyarrhythmias (ATAs). The benefit of RM compared to conventional follow‐up in the detection and management of ATA was assessed in recipients of dual‐chamber pacemakers.

Methods

The multicenter randomized SETAM study enrolled 595 patients in sinus rhythm with a CHA2DS2‐VASc score ≥2, without ATA history and untreated with antiarrhythmics and antithrombotics, randomly assigned to RM (RM‐ON; n = 291) versus ambulatory follow‐up (RM‐OFF; n = 304) during 12.8 ± 3.3 months. ATA occurrence, burden, and management were analyzed together with adverse clinical events.

Results

Patients were 79 ± 8 years old, 63% men, with a CHA2DS2‐VASc score of 3.7± 1.2. ATA were detected in 83 patients (28%) in the RM‐ON versus 66 (22%) in the RM‐OFF group (P = 0.06). The median time between the pacemaker implantation and the first treated ATA was 114 days [44; 241] in the RM‐ON versus 224 days [67; 366] in the RM‐OFF group (hazard ratio [HR] = 0.56; 95% confidence interval [CI]: 0.37–0.86; P = 0.01). Therapies for ATA were initiated in 92 patients and the time to treatment of ATA was shortened by 44% in the RM‐ON group (HR = 0.565; 95% CI: 0.37–0.86; P = 0.01). Over the last 4 months of follow‐up, the mean ATA burden was alleviated by 4 hours/day (18%) in the RM‐ON group. The rate of adverse clinical events was similar in both groups.

Conclusion

Remotely monitored patients were diagnosed and treated earlier for ATA, and subsequently had a lower ATA burden.
Temperature fine‐tunes Mediterranean Arabidopsis thaliana life‐cycle phenology geographically
Authors: Marcer A. , Vidigal D. S. , James P. M. A. , Fortin M.‐J. , Méndez‐Vigo B. , Hilhorst H. W. M. , Bentsink L. , Alonso‐Blanco C. , Picó F. X.
Published: February 2017

To understand how adaptive evolution in life‐cycle phenology operates in plants, we need to unravel the effects of geographic variation in putative agents of natural selection on life‐cycle phenology by considering all key developmental transitions and their co‐variation patterns. We address this goal by quantifying the temperature‐driven and geographically varying relationship between seed dormancy and flowering time in the annual Arabidopsis thaliana across the Iberian Peninsula.

We used data on genetic variation in two major life‐cycle traits, seed dormancy (DSDS50) and flowering time (FT), in a collection of 300 A. thaliana accessions from the Iberian Peninsula. The geographically varying relationship between life‐cycle traits and minimum temperature, a major driver of variation in DSDS50 and FT, was explored with geographically weighted regressions (GWR). The environmentally varying correlation between DSDS50 and FT was analysed by means of sliding window analysis across a minimum temperature gradient.

Maximum local adjustments between minimum temperature and life‐cycle traits were obtained in the southwest Iberian Peninsula, an area with the highest minimum temperatures. In contrast, in off‐southwest locations, the effects of minimum temperature on DSDS50 were rather constant across the region, whereas those of minimum temperature on FT were more variable, with peaks of strong local adjustments of GWR models in central and northwest Spain. Sliding window analysis identified a minimum temperature turning point in the relationship between DSDS50 and FT around a minimum temperature of 7.2 °C. Above this minimum temperature turning point, the variation in the FT/DSDS50 ratio became rapidly constrained and the negative correlation between FT and DSDS50 did not increase any further with increasing minimum temperatures.

The southwest Iberian Peninsula emerges as an area where variation in life‐cycle phenology appears to be restricted by the duration and severity of the hot summer drought. The temperature‐driven varying relationship between DSDS50 and FT detected environmental boundaries for the co‐evolution between FT and DSDS50 in A. thaliana. In the context of global warming, we conclude that A. thaliana phenology from the southwest Iberian Peninsula, determined by early flowering and deep seed dormancy, might become the most common life‐cycle phenotype for this annual plant in the region.
Resource‐directed foraging of the Neotropical mistletoe Struthanthus flexicaulis (Loranthaceae)
Authors: Mourão F. A. , Pereira Pinheiro R. B. , Jacobi C. M. , Figueira J. E. C.
Published: February 2017

Some parasitic plants are capable of vegetative propagation, which allows them access to new hosts and improves nutrient availability. We aimed to determine what factors positively influence this propagation in the xylem‐tapping Struthanthus flexicaulis, focusing on the use of directed foraging as a means of optimising access to resources.

The study site was a rupicolous plant community in southeast Brazil. We evaluated how the success of branch propagation (by contagion) of the mistletoe is influenced by the crown height and density of its main host, the legume Mimosa calodendron. Oriented foraging was tested through comparing the response of mistletoe branches toward a potential host (resources) or a plastic net (no resources).

Successful contagion was related to high density and the departure height of a branch from a host crown. In a high‐density area, 89% of branches reached a new host versus 21% in a low‐density area. Formation of an appressorium on either the plastic nets or hosts elicited branch growth reorientation towards it, as well as development of new branches. These responses were significantly stronger towards hosts than nets, and attributed to effective xylem tapping.

The foraging strategy of S. flexicaulis benefits from branch response (growth and reorientation) to the development of appressoria and their resulting haustoria. The growth of appressoria on non‐resource substrates and the ensuing response optimises the mistletoe spread by allowing these substrates to act as physical support for spreading branches and to infect a host that was previously out of reach.
Fusarium species associated with stalk rot and head blight of grain sorghum in Queensland and New South Wales, Australia
Authors: Kelly L. A. , Tan Y. P. , Ryley M. J. , Aitken E. A. B.
Published: February 2017

Historical records report Fusarium moniliforme sensu lato as the pathogen responsible for Fusarium diseases of sorghum; however, recent phylogenetic analysis has separated this complex into more than 25 species. During this study, surveys were undertaken in three major sorghum‐producing regions in eastern Australia to assess the diversity and frequency of Fusarium species associated with stalk rot‐ and head blight‐infected plants. A total of 523 isolates were collected from northern New South Wales, southern Queensland and central Queensland. Nine Fusarium species were isolated from diseased plants. Pathogenicity tests confirmed F. andiyazi and F. thapsinum were the dominant stalk rot pathogens, whilst F. thapsinum and species within the F. incarnatum–F. equiseti species complex were most frequently associated with head blight.
Avoiding the Asymmetry Problem
Authors: Timmerman Travis
Published: February 2017

If earlier‐than‐necessary death is bad because it deprives individuals of additional good life, then why isn't later‐than‐necessary conception bad for the same reason? Deprivationists have argued that prenatal non‐existence is not bad because it is impossible to be conceived earlier, but postmortem non‐existence is bad because it is possible to live longer. Call this the Impossibility Solution. In this paper, I demonstrate that the Impossibility Solution does not work by showing how it is possible to be conceived earlier in the same senses it is possible to live longer. I then offer a solution to the Asymmetry Problem by suggesting a novel way to separate the badness of each type of non‐existence from the type, and frequency, of attitudes we should have towards each type of non‐existence. Even if both types of non‐existence are equally bad, certain contingent facts about our postmortem non‐existence provide reason for the badness of early deaths to be more frequently salient than the badness of late conceptions.
A Flexible Hierarchical Bayesian Modeling Technique for Risk Analysis of Major Accidents
Authors: Yu Hongyang , Khan Faisal , Veitch Brian
Published: February 2017

Safety analysis of rare events with potentially catastrophic consequences is challenged by data scarcity and uncertainty. Traditional causation‐based approaches, such as fault tree and event tree (used to model rare event), suffer from a number of weaknesses. These include the static structure of the event causation, lack of event occurrence data, and need for reliable prior information. In this study, a new hierarchical Bayesian modeling based technique is proposed to overcome these drawbacks. The proposed technique can be used as a flexible technique for risk analysis of major accidents. It enables both forward and backward analysis in quantitative reasoning and the treatment of interdependence among the model parameters. Source‐to‐source variability in data sources is also taken into account through a robust probabilistic safety analysis. The applicability of the proposed technique has been demonstrated through a case study in marine and offshore industry.
Financing Public Education Facilities: The Role of Elderly Populations and Geographic Mobility
Authors: Schlaffer James S.
Published: February 2017

Objectives

The objective of this study was to explore how the age distribution of voters and their mobility affects the probability of passing bonds for the purpose of improving education facilities and to demonstrate the differential motivations within elderly populations rather than viewing elderly voters as a single voting bloc.

Method

The study examines California education bond results using logistic regressions to determine the effect that the elderly population as a percent of the population has on the probability of passage. The study also includes the percentage of the elderly population that recently moved into the school district to account for differences in community connection among elderly populations.

Result

The result of the study determines that the effect of recent elderly movers on the probability of bond passage is found to be negative, whereas no evidence is found that older households resist educational funding.

Conclusion

The conclusion of this study is that part of the reason why the previous literature surrounding the “Gray Peril” has been inconclusive is that the elderly population is not uniform in its opposition to education spending and that other factors such as community connection help determine the strength of that opposition in the elderly community.
Housework Allocation in Germany: The Role of Income and Gender Identity
Authors: Procher Vivien , Ritter Nolan , Vance Colin
Published: February 2017

Objectives

This article analyzes how couples allocate housework against the backdrop of three questions: (1) Does an individual's income—both in absolute and relative terms—influence his or her contribution to housework? (2) If so, does the magnitude of this influence differ by gender? and (3) How important are traditional gender roles on housework allocation?

Methods

We apply panel regression techniques to longitudinal German household data.

Results

We find that as both the share and absolute level of income increase, the amount of housework undertaken by wives and husbands decreases. Traditional gender roles also underpin housework allocation, which is evidenced by women increasing their housework if they earn more than their partner.

Conclusion

While we find a negative association between earnings and housework, policy measures to ease the double burden borne by working women may have only a modest effect owing to the persistence of traditional gender conceptions.
Social Media Campaigning: Mobilization and Fundraising on Facebook
Authors: Auter Zachary J. , Fine Jeffrey A.
Published: February 2017

Objective

We investigate why certain candidates for the U.S. Senate are more likely to use social media for mobilization and fundraising.

Methods

Through content analysis of nearly 15,000 Facebook posts made by candidates for the U.S. Senate, we examine how candidate and campaign characteristics shape social media use.

Results

We find this type of campaigning is most common among challengers and Tea Party candidates who lack the name recognition and resources of more established candidates. Additionally, race characteristics, such as competitiveness and the relative positioning of candidates, influence social media posting strategies, with candidates in competitive races and candidates trailing their opponent more actively engaging in social media campaigning.

Conclusions

While nearly all candidates engage in some level of campaigning on social media, candidates in competitive races, challengers, and underdog candidates adopt these types of strategies most frequently on Facebook.
A novel HLA‐E allele, HLA‐E*01:01:01:07, identified in a Chinese leukemia patient
Authors: Wang S.‐X. , Xu Y.‐P. , He Li.‐M.
Published: February 2017

A novel HLA‐E allele,
HLA‐E*01:01:01:07, was identified in a Chinese leukemia patient.
Does targeting children with hygiene promotion messages work? The effect of handwashing promotion targeted at children, on diarrhoea, soil‐transmitted helminth infections and behaviour change, in low‐ and middle‐income countries
Authors: Watson Julie A. , Ensink Jeroen H. J. , Ramos Monica , Benelli Prisca , Holdsworth Elizabeth , Dreibelbis Robert , Cumming Oliver
Published: February 2017

Objectives

To synthesise evidence on the effect of handwashing promotion interventions targeting children, on diarrhoea, soil‐transmitted helminth infection and handwashing behaviour, in low‐ and middle‐income country settings.

Methods

A systematic review of the literature was performed by searching eight databases, and reference lists were hand‐searched for additional articles. Studies were reviewed for inclusion according to pre‐defined inclusion criteria and the quality of all studies was assessed.

Results

Eight studies were included in this review: seven cluster‐randomised controlled trials and one cluster non‐randomised controlled trial. All eight studies targeted children aged 5–12 attending primary school but were heterogeneous for both the type of intervention and the reported outcomes so results were synthesised qualitatively. None of the studies were of high quality and the large majority were at high risk of bias. The reported effect of child‐targeted handwashing interventions on our outcomes of interest varied between studies. Of the different interventions reported, no one approach to promoting handwashing among children appeared most effective.

Conclusion

Our review found very few studies that evaluated handwashing interventions targeting children and all had various methodological limitations. It is plausible that interventions which succeed in changing children's handwashing practices will lead to significant health impacts given that much of the attributable disease burden is concentrated in that age group. The current paucity of evidence in this area, however, does not permit any recommendations to be made as to the most effective route to increasing handwashing with soap practice among children in LMIC.
Translation regulation in plants: an interesting past, an exciting present and a promising future
Authors: Merchante Catharina , Stepanova Anna N. , Alonso Jose M.
Published: February 2017

Changes in gene expression are at the core of most biological processes, from cell differentiation to organ development, including the adaptation of the whole organism to the ever‐changing environment. Although the central role of transcriptional regulation is solidly established and the general mechanisms involved in this type of regulation are relatively well understood, it is clear that regulation at a translational level also plays an essential role in modulating gene expression. Despite the large number of examples illustrating the critical role played by translational regulation in determining the expression levels of a gene, our understanding of the molecular mechanisms behind such types of regulation has been slow to emerge. With the recent development of high‐throughput approaches to map and quantify different critical parameters affecting translation, such as RNA structure, protein–RNA interactions and ribosome occupancy at the genome level, a renewed enthusiasm toward studying translation regulation is warranted. The use of these new powerful technologies in well‐established and uncharacterized translation‐dependent processes holds the promise to decipher the likely complex and diverse, but also fascinating, mechanisms behind the regulation of translation.
Resolving fine‐grained dynamics of retrotransposons: comparative analysis of inferential methods and genomic resources
Authors: Choudhury Rimjhim Roy , Neuhaus Jean‐Marc , Parisod Christian
Published: February 2017

Transposable elements support genome diversification, but comparison of their proliferation and genomic distribution within and among species is necessary to characterize their role in evolution. Such inferences are challenging because of potential bias with incomplete sampling of repetitive genome regions. Here, using the assembled genome as well as genome skimming datasets in Arabis alpina, we assessed the limits of current approaches inferring the biology of transposable elements. Long terminal repeat retrotransposons (LTR‐RTs) identified in the assembled genome were classified into monophyletic lineages (here called tribes), including families of similar copies in Arabis along with elements from related Brassicaceae. Inference of their dynamics using divergence of LTRs in full‐length copies and mismatch distribution of genetic variation among all copies congruently highlighted recent transposition bursts, although ancient proliferation events were apparent only with mismatch distribution. Similar inferences of LTR‐RT dynamics based on random sequences from genome skimming were highly correlated with assembly‐based estimates, supporting accurate analyses from shallow sequencing. Proportions of LTR‐RT copies next to genes from both assembled genomes and genome skimming were congruent, pointing to tribes being over‐ or under‐represented in the vicinity of genes. Finally, genome skimming at low coverage revealed accurate inferences of LTR‐RT dynamics and distribution, although only the most abundant families appeared robustly analysed at 0.1X. Examining the pitfalls and benefits of approaches relying on different genomic resources, we highlight that random sequencing reads represent adequate data suitably complementing biased samples of LTR‐RT copies retrieved from assembled genomes towards comprehensive surveys of the biology of transposable elements.
The enchanted path: magic and modernism in psychogeographical walking
Authors: Bonnett Alastair
Published: February 2017

Geographers have a developing interest in the place of enchantment and the ‘extra‐ordinary’ in the modern city. The paper shows that magic has a significant role in the work of many psychogeographical writers, artists and activists, and argues that this phenomenon needs to be understood in the context of the wider use of magic as a site and symbol of creativity and subversion in modernist cultural expression. Drawing on a survey of British psychogeographical forms and a more detailed study of three London literary examples, it examines how psychogeographical walkers have expanded and developed ‘magical modernism’. Across the varied terrain of psychogeographical walking, magic is used to conjure an openness and vulnerability to voices ‘hidden’ in the landscape. As well as providing more in‐depth discussion of these themes, the three examples of London psychogeography that I explore complicate them by illustrating further specific and diverse uses of magic – namely, magic as environmentalist critique, magic as humour/humour as magic and magic as activism.
Effects From Complex Terrain on Wind-Turbine Performance
Authors: Hyvärinen Ann , Segalini Antonio
Published: February 2017

In this work, experimental measurements are made to study wind turbines over complex terrains and in presence of the atmospheric boundary layer. Thrust and power coefficients for single and multiple turbines are measured when introducing sinusoidal hills and spires inducing an artificial atmospheric boundary layer. Additionally, wake interaction effects are studied, and inflow velocity profiles are characterized using hot-wire anemometry. The results indicate that the introduced hills have a positive impact on the wind-turbine performance and that wake-interaction effects are significantly reduced during turbulent inflow conditions.
Unsteady Heat Transfer and Pressure Measurements on the Airfoils of a Rotating Transonic Turbine With Multiple Cooling Configurations
Authors: Nickol Jeremy B. , Mathison Randall M. , Dunn Michael G. , Liu Jong S. , Malak Malak F.
Published: February 2017

Measurements are presented for a high-pressure transonic turbine stage operating at design-corrected conditions with forward and aft purge flow and blade film cooling in a short-duration blowdown facility. Four different film-cooling configurations are investigated: simple cylindrical-shaped holes, diffusing fan-shaped holes, an advanced-shaped hole, and uncooled blades. A rainbow turbine approach is used so each of the four blade types comprises a wedge of the overall bladed disk and is investigated simultaneously at identical speed and vane exit conditions. Double-sided Kapton heat-flux gauges are installed at midspan on all three film-cooled blade types, and single-sided Pyrex heat-flux gauges are installed on the uncooled blades. Kulite pressure transducers are installed at midspan on cooled blades with round and fan-shaped cooling holes. Experimental results are presented both as time-averaged values and as time-accurate ensemble-averages. In addition, the results of a steady Reynolds-averaged Navier–Stokes computational fluid dynamics (RANS CFD) computation are compared to the time-averaged data. The computational and experimental results show that the cooled blades reduce heat transfer into the blade significantly from the uncooled case, but the overall differences in heat transfer among the three cooling configurations are small. This challenges previous conclusions for simplified geometries that show shaped cooling holes outperforming cylindrical holes by a great margin. It suggests that the more complicated flow physics associated with an airfoil operating in an engine-representative environment reduces the effectiveness of the shaped cooling holes. Time-accurate comparisons provide some insight into the complicated interactions that are driving these flows and make it difficult to characterize cooling benefits.
Assessment of the Pitting Corrosion Degradation Lifetime: A Case
Study of Boiler Tubes
Authors: Moghanlou Lida Naseh , Pourgol-Mohammad Mohammad
Published: February 2017

Corrosion degradation is a common problem for boiler tubes in power plants, resulting in an unscheduled plant shutdown. In this research, degradation of the corrosion is investigated for boiler tubes by estimating the corrosion lifetime. A special focus is made on the corrosion failures, important failure modes, and mechanisms for the metallic boiler tubes via failure modes and effect analysis (FMEA) method, thereby evaluating the pitting corrosion as the most common failure mode in the tubes. Majority of the available approaches estimates lifetime of the pitting corrosion by deterministic approaches, in which the results are valid only for limited conditions. In order to improve deficiencies of available models, a stochastic method is proposed here to study the corrosion life. The temporal behavior of the metal degradation is analyzed in different conditions through the developed approach, and a proper degradation model is selected. Uncertainty intervals/distributions are determined for some of the model parameters. The deterministic model is converted to a probabilistic model by taking into account the variability of the uncertain input parameters. The model is simulated using Monte Carlo method via simple sampling. The result of the life estimation is updated by the Bayesian framework using Monte Carlo Markov Chain. Finally, for the element that is subjected to the pitting corrosion degradation, the life distribution is obtained. The modeling results show that the pitting corrosion has stochastic behavior with lognormal distribution as proper fit for the pitting corrosion behavior. In order to validate the results, the estimations were compared with the power plant field failure data.
Single‐isocenter hybrid IMRT plans versus two‐isocenter conventional plans and impact of intrafraction motion for the treatment of breast cancer with supraclavicular lymph nodes involvement
Authors: Amoush Ahmad , Murray Eric , Yu Jennifer S. , Xia Ping
Published: February 2017

The purpose of this study was to compare the single‐isocenter, four‐field hybrid IMRT with the two‐isocenter techniques to treat the whole breast and supraclavicular fields and to investigate the intrafraction motions in both techniques in the superior direction. Fifteen breast cancer patients who underwent lumpectomy and adjuvant radiation to the whole breast and supraclavicular (SCV) fossa at our institution were selected for this study. Two planning techniques were compared for the treatment of the breast and SCV lymph nodes. The patients were divided into three subgroups according to the whole breast volume. For the two‐isocenter technique, conventional wedged or field‐within‐a‐field tangents (FIF) were used to match with the same anterior field for the SCV region. For the single‐isocenter technique, four‐field hybrid IMRT was used for the tangent fields matched with a half blocked anterior field for the SCV region. To simulate the intrafraction uncertainties in the longitudinal direction for both techniques, the treatment isocenters were shifted by 1 mm and 2 mm in the superior direction. The average breast clinical tumor volume (CTV) receiving 100% () of the prescription dose (50 Gy) was and for the for two‐isocenter and single‐isocenter plans (), respectively. The breast CTV receiving 95% of the prescription dose () was close to 100% in both techniques. The average breast CTV receiving 105% () of the prescription dose was and (). The percentage volume of the breast CTV receiving 110% of the dose was in the two‐isocentric technique vs. in the single‐isocentric technique. The average uniformity index was vs. in both techniques (), but had no clinical impact. The percentage volume of the contralateral breast receiving a dose of 1 Gy was less than 2.3% in small breast patients and insignificant for medium and large breast sizes. The percentage of the total lung volume receiving () and the heart receiving () were 13.6% vs. 14.3% () and 1.25% vs. 1.2% (), respectively. Shifting the treatment isocenter by 1 mm and 2 mm superiorly showed that the average maximum dose to 1 cc of the breast volume was Gy and Gy in the two‐isocentric technique vs. Gy and Gy in the single‐isocentric technique (, 0.87), respectively. The single‐isocenter technique using four‐field hybrid IMRT approach resulted in comparable plan quality as the two‐isocentric technique. The single‐isocenter technique is more sensitive to intrafraction motion in the superior direction compared to the two‐isocentric technique. The advantages of the single‐isocenter include elimination of isocentric errors due to couch and collimator rotations and reduction in treatment time. This study supports consideration of a single‐isocenter four‐field hybrid IMRT technique for patients undergoing breast and supraclavicular nodal irradiation.

PACS number: 87.55.D, 87.55.de, 87.55.dk,
Characterization of MOSFET dosimeters for low‐dose measurements in maxillofacial anthropomorphic phantoms
Authors: Koivisto Juha H. , Wolff Jan E. , Kiljunen Timo , Schulze Dirk , Kortesniemi Mika
Published: February 2017

The aims of this study were to characterize reinforced metal‐oxide‐semiconductor field‐effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low‐dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50–90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point‐dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, ) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low‐dose limit. The sensitivity was independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was −8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD‐comparable low‐dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in vivo measurements () the sensitivity is too low.

PACS number: 87.50.wj
Influence of internal fixation systems on radiation therapy for spinal tumor
Authors: Li Jingfeng , Yan Lei , Wang Jianping , Cai Lin , Hu Dongcai
Published: February 2017

In this study, the influence of internal fixation systems on radiation therapy for spinal tumor was investigated in order to derive a theoretical basis for adjustment of radiation dose for patients with spinal tumor and internal fixation. Based on a common method of internal fixation after resection of spinal tumor, different models of spinal internal fixation were constructed using the lumbar vertebra of fresh domestic pigs and titanium alloy as the internal fixation system. Variations in radiation dose in the vertebral body and partial spinal cord in different types of internal fixation were studied under the same radiation condition (6 MV and 600 mGy) in different fixation models and compared with those irradiated based on the treatment planning system (TPS). Our results showed that spinal internal fixation materials have great impact on the radiation dose absorbed by spinal tumors. Under the same radiation condition, the influence of anterior internal fixation material or combined anterior and posterior approach on radiation dose at the anterior border of the vertebral body was the greatest. Regardless of the kinds of internal fixation method employed, radiation dose at the anterior border of the vertebral body was significantly different from that at other positions. Notably, the influence of posterior internal fixation material on the anterior wall of the vertebral canal was the greatest. X‐ray attenuation and scattering should be taken into consideration for most patients with bone metastasis that receive fixation of metal implants. Further evaluation should then be conducted with modified TPS in order to minimize the potentially harmful effects of inappropriate radiation dose.

PACS number: 87.55.D‐
Analysis of direct clinical consequences of MLC positional errors in volumetric‐modulated arc therapy using 3D dosimetry system
Authors: Nithiyanantham Karthikeyan , Mani Ganesh K. , Subramani Vikraman , Mueller Lutz , Palaniappan Karrthick K. , Kataria Tejinder
Published: February 2017

In advanced, intensity‐modulated external radiotherapy facility, the multileaf collimator has a decisive role in the beam modulation by creating multiple segments or dynamically varying field shapes to deliver a uniform dose distribution to the target with maximum sparing of normal tissues. The position of each MLC leaf has become more critical for intensity‐modulated delivery (step‐and‐shoot IMRT, dynamic IMRT, and VMAT) compared to 3D CRT, where it defines only field boundaries. We analyzed the impact of the MLC positional errors on the dose distribution for volumetric‐modulated arc therapy, using a 3D dosimetry system. A total of 15 VMAT cases, five each for brain, head and neck, and prostate cases, were retrospectively selected for the study. All the plans were generated in Monaco 3.0.0v TPS (Elekta Corporation, Atlanta, GA) and delivered using Elekta Synergy linear accelerator. Systematic errors of were introduced in the MLC bank of the linear accelerator and the impact on the dose distribution of VMAT delivery was measured using the COMPASS 3D dosimetry system. All the plans were created using single modulated arcs and the dose calculation was performed using a Monte Carlo algorithm in a grid size of 3 mm. The clinical endpoints , and , D50% were taken for the evaluation of the target and critical organs doses, respectively. A significant dosimetric effect was found for many cases even with 0.5 mm of MLC positional errors. The average change of dose to PTV for , and was 5.15%, 2.58%, and 0.96% for brain cases; 7.19%, 3.67%, and 1.56% for head and neck cases; and 8.39%, 4.5%, and 1.86% for prostate cases, respectively. The average deviation of dose was 5.4%, 2.8%, and 0.83% for brainstem in brain cases; 8.2%, 4.4%, and 1.9% for spinal cord in H&N; and 10.8%, 6.2%, and 2.1% for rectum in prostate cases, respectively. The average changes in dose followed a linear relationship with the amount of MLC positional error, as can be expected. MLC positional errors beyond showed a significant influence on the intensity‐modulated dose distributions. It is, therefore, recommended to have a cautious MLC calibration procedure to sufficiently meet the accuracy in dose delivery.

PACS number: 87.56
Adaptive optimization by 6 DOF robotic couch in prostate volumetric IMRT treatment: rototranslational shift and dosimetric consequences
Authors: Chiesa Silvia , Placidi Lorenzo , Azario Luigi , Mattiucci Gian Carlo , Greco Francesca , Damiani Andrea , Mantini Giovanna , Frascino Vincenzo , Piermattei Angelo , Valentini Vincenzo , Balducci Mario
Published: February 2017

The purpose of this study was to investigate the magnitude and dosimetric relevance of translational and rotational shifts on IGRT prostate volumetric‐modulated arc therapy (VMAT) using Protura six degrees of freedom (DOF) Robotic Patient Positioning System. Patients with cT3aN0M0 prostate cancer, treated with VMAT simultaneous integrated boost (VMAT‐SIB), were enrolled. PTV2 was obtained adding 0.7 cm margin to seminal vesicles base (CTV2), while PTV1 adding to prostate (CTV1) 0.7 cm margin in all directions, except 1.2 cm, as caudal margin. A daily CBCT was acquired before dose delivery. The translational and rotational displacements were corrected through Protura Robotic Couch, collected and applied to the simulation CT to obtain a translated CT (tCT) and a rototranslated CT (rtCT) on which we recalculated the initial treatment plan (TP). We analyzed the correlation between dosimetric coverage, organs at risk (OAR) sparing, and translational or rotational displacements. The dosimetric impact of a rototranslational correction was calculated. From October 2012 to September 2013, a total of 263 CBCT scans from 12 patients were collected. Translational shifts were in 81% of patients and the rotational shifts were in 93% of patient scans. The dosimetric analysis was performed on 172 CBCT scans and calculating 344 VMAT‐TP. Two significant linear correlations were observed between yaw and the V20 femoral heads and between pitch rotation and V50 rectum (); rototranslational correction seems to impact more on PTV2 than on PTV1, especially when margins are reduced. Rotational errors are of dosimetric significance in sparing OAR and in target coverage. This is relevant for femoral heads and rectum because of major distance from isocenter, and for seminal vesicles because of irregular shape. No correlation was observed between translational and rotational errors. A study considering the intrafractional error and the deformable registration is ongoing.

PACS number: 87.55.de