bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of Wnt/β‐catenin signaling downregulates P‐glycoprotein and reverses multi‐drug resistance of cholangiocarcinoma
Authors: Shen Dong‐Yan , Zhang Wei , Zeng Xin , Liu Chang‐Qin
Published: July 2013

The development of multi‐drug resistance (MDR) represents a major obstacle in the successful treatment of cancers. However, the factors and mechanisms that lead to MDR in cholangiocarcinoma (CCA), a chemoresistant bile duct carcinoma with a poor prognosis, remain unclear. In this study, we established a human MDR CCA cell line QBC939/5‐FU. Compared with QBC939 cells, a rounder shape, a higher nuclear–cytoplasmic ratio, a shorter cell cycle, faster growth and resistance to chemotherapeutics are major characteristics of QBC939/5‐FU cells. P‐glycoprotein (P‐gp) and β‐catenin were upregulated in QBC939/5‐FU cells. Furthermore, the drug susceptibility of QBC939 cells to common chemotherapeutics was significantly decreased after Wnt3a treatment, whereas inhibition of Wnt/β‐catenin pathway by β‐catenin siRNA reversed the MDR of QBC939/5‐FU cells to chemotherapeutics. Molecular study revealed that activation of Wnt/β‐catenin pathway resulted in upregulation of P‐gp and contributed to MDR of QBC939/5‐FU cells. Extraction of Siamese Crocodile 3 (ESC‐3) bile enhanced the drug sensitivity of QBC939/5‐FU cells to 5‐FU, paralleled with downregulation of β‐catenin and P‐gp. The association of Wnt/β‐catenin pathway and P‐gp was further confirmed by the clinical data for CCA tissues. Our study represents the first implication of Wnt/β‐catenin activation in the MDR of CCA, which may be a beneficial target for the clinical treatment of CCA.
Which is false: Oxaliplatin or fluoropyrimidine? An analysis of patients with KRAS wild‐type metastatic colorectal cancer treated with first‐line epidermal growth factor receptor monoclonal antibody
Authors: Wen Feng , Tang Ruilei , Sang Yaxiong , Li Meng , Hu Qiancheng , Du Zedong , Zhou Yi , Zhang Pengfei , He Xiaofeng , Li Qiu
Published: July 2013

This meta‐analysis was performed to determine whether the addition of monoclonal antibodies (mAbs) of epidermal growth factor receptor (EGFR) to oxaliplatin‐based chemotherapy treatment improves efficacy in KRAS wild‐type metastatic colorectal cancer (mCRC), and whether infusional 5‐fluorouracil (5‐FU) and oxaliplatin is a preferred combination for EGFR mAbs. Oxaliplatin (including treatment), EGFR mAbs, first‐line treatment, KRAS wild‐type, and mCRC were used as key words. The PRIME, OPUS, COIN, and NORDIC VII trials were identified by two independent authors. Time‐to‐event outcomes of overall survival (OS) and progression‐free survival (PFS) were analyzed using HRs (hazard ratios) with fixed effect, and response rate (RR) using odd ratios (OR) with fixed effect. A total of 1767 patients who were KRAS wild‐type were included in this meta‐analysis, with 866 patients in the mAbs and chemotherapy combination group and 901 patients in the chemotherapy alone group. The addition of mAbs to oxaliplatin‐based chemotherapy in patients with KRAS wild‐type mCRC as first‐line treatment resulted in significant improvements in PFS (HR = 0.88; 95% confidence interval (CI), 0.79–0.99; P = 0.03) and response rate (RR) (OR = 1.38; 95% CI, 1.14–1.66; P = 0.009) compared with chemotherapy alone, but the difference in OS was not significant (HR = 0.96; 95% CI, 0.85–1.08; P = 0.48). However, the differences in OS and PFS were not significant when mAbs were added to bolus 5‐FU or capecitabine‐based regimens compared with chemotherapy alone, whereas PFS improved with an infusional 5‐FU and oxaliplatin combination (P = 0.06; PFS, HR = 0.76; 95% CI, 0.65–0.86; P = 0.0002), and even OS was marginally significant, which was consistent with the subgroup analysis of cetuximab and panitumumab. EGFR mAbs combined with oxaliplatin and an infusional 5‐FU regimen was associated with significantly improved RR, PFS and OS as first‐line treatment in KRAS wild‐type mCRC.
Body masses, functional responses and predator–prey stability
Authors: Kalinkat Gregor , Schneider Florian D. , Digel Christoph , Guill Christian , Rall Björn C. , Brose Ulrich
Published: July 2013

The stability of ecological communities depends strongly on quantitative characteristics of population interactions (type‐II vs. type‐III functional responses) and the distribution of body masses across species. Until now, these two aspects have almost exclusively been treated separately leaving a substantial gap in our general understanding of food webs. We analysed a large data set of arthropod feeding rates and found that all functional‐response parameters depend on the body masses of predator and prey. Thus, we propose generalised functional responses which predict gradual shifts from type‐II predation of small predators on equally sized prey to type‐III functional‐responses of large predators on small prey. Models including these generalised functional responses predict population dynamics and persistence only depending on predator and prey body masses, and we show that these predictions are strongly supported by empirical data on forest soil food webs. These results help unravelling systematic relationships between quantitative population interactions and large‐scale community patterns.
Methcathinone‐induced parkinsonism results from permanent brain damage: a message for the masses
Authors: Fasano A.
Published: July 2013

Click here to view the accompanying paper in this issue.
Photosynthesis of temperate Eucalyptus globulus trees outside their native range has limited adjustment to elevated CO2 and climate warming
Authors: Crous Kristine Y. , Quentin Audrey G. , Lin Yan‐Shih , Medlyn Belinda E. , Williams David G. , Barton Craig V. M. , Ellsworth David S.
Published: July 2013

Eucalyptus species are grown widely outside of their native ranges in plantations on all vegetated continents of the world. We predicted that such a plantation species would show high potential for acclimation of photosynthetic traits across a wide range of growth conditions, including elevated [CO2] and climate warming. To test this prediction, we planted temperate Eucalyptus globulus Labill. seedlings in climate‐controlled chambers in the field located >700 km closer to the equator than the nearest natural occurrence of this species. Trees were grown in a complete factorial combination of elevated CO2 concentration (eC; ambient [CO2] +240 ppm) and air warming treatments (eT; ambient +3 °C) for 15 months until they reached ca. 10 m height. There was little acclimation of photosynthetic capacity to eC and hence the CO2‐induced photosynthetic enhancement was large (ca. 50%) in this treatment during summer. The warming treatment significantly increased rates of both carboxylation capacity (Vcmax) and electron transport (Jmax) (measured at a common temperature of 25 °C) during winter, but decreased them significantly by 20–30% in summer. The photosynthetic CO2 compensation point in the absence of dark respiration (Γ*) was relatively less sensitive to temperature in this temperate eucalypt species than for warm‐season tobacco. The temperature optima for photosynthesis and Jmax significantly changed by about 6 °C between winter and summer, but without further adjustment from early to late summer. These results suggest that there is an upper limit for the photosynthetic capacity of E. globulus ssp. globulus outside its native range to acclimate to growth temperatures above 25 °C. Limitations to temperature acclimation of photosynthesis in summer may be one factor that defines climate zones where E. globulus plantation productivity can be sustained under anticipated global environmental change.
C‐terminus of the Sgf73 subunit of SAGA and SLIK is important for retention in the larger complex and for heterochromatin boundary function
Authors: Kamata Kazuma , Hatanaka Akira , Goswami Gayatri , Shinmyozu Kaori , Nakayama Jun‐ichi , Urano Takeshi , Hatashita Masanori , Uchida Hiroyuki , Oki Masaya
Published: July 2013

The budding yeast Saccharomyces cerevisiae contains active and inactive chromatin separated by boundary domains. Previously, we used genome‐wide screening to identify 55 boundary‐related genes. Here, we focus on Sgf73, a boundary protein that is a component of the Spt‐Ada‐Gcn5 acetyltransferase (SAGA) and SLIK (SAGA‐like) complexes. These complexes have histone acetyltransferase (HAT) and histone deubiquitinase activity, and Sgf73 is one of the factors necessary to anchor the deubiquitination module. Domain analysis of Sgf73 was carried out, and the minimum region (373–402 aa) essential for boundary function was identified. This minimum region does not include the domain involved in anchoring the deubiquitination module, suggesting that the histone deubiquitinase activity of Sgf73 is not important for its boundary function. Next, Sgf73‐mediated boundary function was analyzed in disruption strains in which different protein subunits of the SAGA/SLIK/ADA complexes were deleted. Deletion of ada2, ada3 or gcn5 (a HAT module component) caused complete loss of the boundary function of Sgf73. The importance of SAGA or SLIK complex binding to the boundary function of Sgf73 was also analyzed. Western blot analysis detected both the full‐length and truncated forms of Spt7, suggesting that SAGA and SLIK complex formation is important for the boundary function of Sgf73.
Comparison of the anaesthetic efficacy of epinephrine concentrations (1 : 80 000 and 1 : 200 000) in 2% lidocaine for inferior alveolar nerve block in patients with symptomatic irreversible pulpitis: a randomized, double‐blind clinical trial
Authors: Aggarwal V. , Singla M. , Miglani S. , Kohli S.
Published: July 2013

Aim

The aim of this randomized controlled, double‐blind trial was to comparatively evaluate the anaesthetic efficacy and injection pain of 1.8 mL of 2% lidocaine with different concentrations of epinephrine (1 : 80 000 and 1 : 200 000) in patients with symptomatic irreversible pulpitis.

Methodology

Sixty‐two adult volunteers, actively experiencing pain, were randomly allocated into 2 groups and received 1.8 mL of 2% lidocaine with either 1 : 80 000 or 1 : 200 000 epinephrine concentration. Endodontic access preparation was initiated 15 min after the initial IANB. Pain during treatment was recorded using the Heft‐Parker visual analogue scale (HP VAS). The primary outcome measure, and the definition of ‘success’, was the ability to undertake pulp access and canal instrumentation with no or mild pain (HP VAS score <55 mm). Secondary outcome measure was the pain experienced during LA solution deposition. Statistical analysis was performed using Mann–Whitney U‐test and chi‐square test.

Results

The anaesthetic success rates of 2% lidocaine solutions containing 1 : 80 000 and 1 : 200 000 epinephrine concentrations were 20% and 28%, respectively. The difference was not statistically significant. There was also no significant difference in the pain experienced during deposition of the solutions.

Conclusions

Two percent lidocaine solution used for IANB achieved similar success rates when used with 1 : 80 000 or 1 : 200 000 epinephrine concentration.
Neonatal Lupus Erythematosus Mimicking Extensive Capillary Malformation
Authors: Vílchez‐Márquez Francisco , Martín‐Fuentes Adriana , Conejero Raquel , Hernández‐Martín Angela , Colmenero Isabel , Nieme Constanza , Fernández‐Toral Joaquín , Torrelo Antonio
Published: July 2013

Abstract:  Neonatal lupus erythematosus is an uncommon transplacentally acquired autoimmune disorder. We report a 7‐month‐old boy with cutaneous involvement of neonatal lupus erythematosus mimicking an extensive capillary malformation.
The role of team climate in the management of emotional labour: implications for nurse retention
Authors: Cheng Cindy , Bartram Timothy , Karimi Leila , Leggat Sandra G.
Published: July 2013

Aims

This article examines the relationships among emotional labour, team climate, burnout, perceived quality of care and turnover intention among nurses in Australia, with the aim of addressing nurse retention and burnout.

Background

Emotional labour refers to the regulation of emotion during interpersonal transactions. It may involve faking unfelt emotions, hiding genuine emotions and deep acting whereby the individuals attempt to influence their inner feelings to induce the appropriate outward countenance. Currently, there is a dearth of literature that investigates the link between emotional labour and perceived quality of care and ultimately turnover intention. The contribution of team climate in the relationship between emotional labour and burnout is still uncertain.

Design

A cross‐sectional quantitative study conducted with self‐completed questionnaires.

Methods

The study was conducted in 2011 with 201 registered nurses. Validated measures were used to measure the aforementioned constructs. Confirmatory factor analyses were used to examine the factor structure of the measured variables and hypotheses were tested using structural equation modelling.

Results

The final model demonstrates that faking has a significant negative influence on perceived quality of care. Hiding predicts burnout, leading to an increase in turnover intention. Team climate moderates the relationship between hiding and burnout, which may subsequently influence turnover intention.

Conclusion

The establishment of a strong team climate may help nurses to manage the emotional demands of their role, promote their well‐being and retention.
Gender‐bias hate crimes: what constitutes a hate crime from a potential juror's perspective?
Authors: Plumm Karyn M. , Terrance Cheryl A.
Published: July 2013

The current study explored hate crime in a nontypical scenario. Label of the crime (first‐degree assault vs. bias‐motivated assault) and gender of the victim were varied within the context of an attack perpetrated within other gender dyads (i.e., when the victim was female, the perpetrator was male, and vice versa). Results indicated that participants in the assault condition were more likely to find the defendant guilty than those in the hate crime condition. Participants also made differential attributions of victim blame, such that those in the assault condition found the victim to be more mentally unstable than those in the hate crime condition.
Diet patterns are associated with demographic factors and nutritional status in South Indian children
Authors: Kehoe Sarah H. , Krishnaveni Ghattu V. , Veena Sargoor R. , Guntupalli Aravinda M. , Margetts Barrie M. , Fall Caroline H.D. , Robinson Sian M.
Published: July 2013

The burden of non‐communicable chronic disease (NCD) in India is increasing. Diet and body composition ‘track’ from childhood into adult life and contribute to the development of risk factors for NCD. Little is known about the diet patterns of Indian children. We aimed to identify diet patterns and study associations with body composition and socio‐demographic factors in the Mysore Parthenon Study cohort. We collected anthropometric and demographic data from children aged 9.5 years (n = 538). We also administered a food frequency questionnaire and measured fasting blood concentrations of folate and vitamin B12. Using principal component analysis, we identified two diet patterns. The ‘snack and fruit’ pattern was characterised by frequent intakes of snacks, fruit, sweetened drinks, rice and meat dishes and leavened breads. The ‘lacto‐vegetarian’ pattern was characterised by frequent intakes of finger millet, vegetarian rice dishes, yoghurt, vegetable dishes and infrequent meat consumption. Adherence to the ‘snack and fruit’ pattern was associated with season, being Muslim and urban dwelling. Adherence to the lacto‐vegetarian pattern was associated with being Hindu, rural dwelling and a lower maternal body mass index. The ‘snack and fruit’ pattern was negatively associated with the child's adiposity. The lacto‐vegetarian pattern was positively associated with blood folate concentration and negatively with vitamin B12 concentration. This study provides new information on correlates of diet patterns in Indian children and how diet relates to nutritional status. Follow‐up of these children will be important to determine the role of these differences in diet in the development of risk factors for NCD including body composition.
Naturalizing Moral Justification: Rethinking the Method of Moral Epistemology
Authors: Tobin Theresa W. , Jaggar Alison M.
Published: July 2013

The companion piece to this article, “Situating Moral Justification,” challenges the idea that moral epistemology's mission is to establish a single, all‐purpose reasoning strategy for moral justification because no reasoning practice can be expected to deliver authoritative moral conclusions in all social contexts. The present article argues that rethinking the mission of moral epistemology requires rethinking its method as well. Philosophers cannot learn which reasoning practices are suitable to use in particular contexts exclusively by exploring logical relations among concepts. Instead, in order to understand which reasoning practices are capable of justifying moral claims in different types of contexts, we need to study empirically the relationships between reasoning practices and the contexts in which they are used. The article proposes that philosophers investigate case studies of real‐world moral disputes in which people lack shared cultural assumptions and/or are unequal in social power. It motivates and explains the proposed case study method and illustrates the philosophical value of this method through a case study.
Emergence patterns and ecological associations of some haematophagous blackfly species along an oligotrophic hydrosystem
Authors: IVKOVIĆ M. , KESIĆ M. , MIHALJEVIĆ Z. , KÚDELA M.
Published: July 2013

Emergence patterns of blackflies (Diptera: Simuliidae) were investigated for 2 years at nine sites in the Plitvice Lakes area of Croatia, using pyramid‐type traps. A total of 38 012 specimens representing 10 haematophagous species were collected. The dominant species was Simulium angustipes Edwards, 1915, a vector transmitting avian trypanosomes. Water temperature, alkalinity, conductivity and habitat type represented the factors with the greatest degree of influence on blackfly species composition, structure and distribution along a longitudinal gradient of this oligotrophic karstic hydrosystem. Simulium angustipes was highly associated with lake outlets. The blackfly communities at all sites were dominated by species typical of the rhithral zone, but there was a shift in species composition along a longitudinal gradient from the hypocrenal–epirhithral to the epirhithral–metarhithral zone. Multiple generations per year were detected in S. angustipes, whereas in Simulium costatum Friederichs, 1920, the number of generations differed between sites with constant and those with variable water temperature.
Sclerosing peritonitis, a rare complication after intestinal transplant. Report of one case successfully treated with adjustment of immunosuppression
Authors: Rumbo Carolina , Zambernardi Agustina , Cabanne Ana , Rumbo Martin , Gondolesi Gabriel
Published: July 2013

Sclerosing peritonitis is a complication described in different clinical situations, such as patients that underwent prolonged peritoneal dialysis or renal transplantation with previous history of peritoneal dialysis. The origin of this entity is unclear so far and it is believed that several mechanisms may contribute to its development. The hallmark of sclerosing peritonitis is the continuous accumulation of fibrocollagenous deposits in the intestinal wall and mesenteries causing progressive adhesion of the intestinal loops and mesenteric retraction resulting in intestinal obstruction. Also, it has been described as a rare complication after intestinal transplant that might lead to graft failure. In this report, we describe a case of sclerosing peritonitis after intestinal transplantation that was successfully treated with modifications in the immunosuppressive regime allowing restitution of gastrointestinal transit and intestinal autonomy.
Detection and quantification of Ilyonectria spp. associated with black‐foot disease of grapevine in nursery soils using multiplex nested PCR and quantitative PCR
Authors: Agustí‐Brisach C. , Mostert L. , Armengol J.
Published: July 2013

Three nursery fields and three rootstock mother fields from commercial nurseries located in Comunidad Valenciana region (central‐eastern Spain) were surveyed in July 2011 to detect the presence and to quantify Ilyonectria spp. in the soil. In each field, ten soil samples were taken randomly with a soil probe at a depth of 10–30 cm, and 10–20 cm from the base of the plant. Three replicate subsamples (10 g each) were taken from each soil sample. DNA was extracted and a multiplex nested PCR with species‐specific primer pairs (Mac1/MaPa2, Lir1/Lir2 and Pau1/MaPa2) was used to identify the species present. Among the 180 soil DNA samples analysed, Ilyonectria spp. were detected in 172 of them. Ilyonectria macrodidyma complex was the most frequently detected, being identified in 141 samples from all the fields evaluated. However, I. liriodendri was detected in only 16 samples, but was present in all open‐root field nurseries and in two rootstock mother fields. In addition, quantitative PCR (qPCR) assays were done to assess the levels of I. liriodendri and I. macrodidyma‐complex DNA in the soil samples. Detection of Ilyonectria spp. DNA using qPCR correlated with the fields found positive with the nested multiplex PCR. DNA concentrations of Ilyonectria spp. ranged from 0·004 to 1904·8 pg μL−1. In general, samples from rootstock mother fields showed the highest DNA concentrations. The ability to detect and quantify Ilyonectria spp. genomic DNA in soil samples from nursery fields and rootstock mother fields confirms soils from both field types as important inoculum sources for black‐foot pathogens.
Marginal Log-Linear Parameters for Graphical Markov Models
Authors: Evans Robin J. , Richardson Thomas S.
Published: July 2013

Marginal log-linear (MLL) models provide a flexible approach to multivariate discrete data. MLL parameterizations under linear constraints induce a wide variety of models, including models that are defined by conditional independences. We introduce a subclass of MLL models which correspond to acyclic directed mixed graphs under the usual global Markov property. We characterize for precisely which graphs the resulting parameterization is variation independent. The MLL approach provides the first description of acyclic directed mixed graph models in terms of a minimal list of constraints. The parameterization is also easily adapted to sparse modelling techniques, which we illustrate by using several examples of real data.
EVALUATING THE PERFORMANCE OF SMALL SCALE MAIZE PRODUCERS IN NIGERIA: AN INTEGRATED DISTANCE FUNCTION APPROACH
Authors: Aye Goodness C. , Mungatana Eric D.
Published: July 2013

The study evaluates the performance of small scale maize producers in Nigeria using stochastic input distance function (SIDF) and variable returns to scale data envelopment analysis (VRS DEA). Further, it examines the determinants of technical efficiency using the double‐bounded Tobit regression model. Results show that maize farmers are operating below the frontier. Technical efficiency estimates from SIDF and VRS DEA models are 86.7 percent and 85.5 percent, respectively. The efficiency estimates obtained from the two models are positively and significantly correlated. Given the high correlation between the two models in our analysis, and for individual variance and bias reduction, the efficiency scores from these models for each farmer are further combined into a single index using the principal component analysis (PCA) approach. Technical efficiency from the integrated model is 86.2 percent. Our findings show that maize production could still be raised by improving farm efficiency. Age, education, household size, membership of a farmer group, access to credit, and market were found to be statistically significant in explaining technical efficiency, thus emphasizing the need for policy intervention in improving farm efficiency.
Determination of MDR1 gene expression for prediction of chemotherapy tolerance and treatment outcome in dogs with lymphoma
Authors: Gramer I. , Kessler M. , Geyer J.
Published: July 2013

The multidrug resistance gene 1(MDR1) expression levels were analysed in 27 dogs with different types of malignant lymphomas receiving a standard chemotherapy protocol. Blood samples were used for MDR1 real‐time PCR expression analysis. Treatment tolerance and outcome were evaluated on a regular basis by clinical examination and client questioning. Dogs developing severe adverse effects under treatment showed significantly lower basal MDR1 gene expression levels when compared with those who tolerated the drugs well. In the longitudinal MDR1 gene expression analysis during treatment, four dogs showed a greater than two‐fold MDR1 up‐regulation, compared to baseline expression. All four of these dogs, but none of the others, showed disease progression. In conclusion, basal and follow‐up MDR1 gene expression levels could be of predictive value for the occurrence of severe adverse drug reactions and/or the development of MDR during chemotherapy for lymphoma in dogs.
The system optimization perspective for multiproduct supply chain network
Authors: Saee Bostanabad Mina , Mehri-Tekmeh Javad , Mirnia Mirkamal , Dehkharghani Ali Moghanni
Published: July 2013

In this paper, multiproduct supply chain network model is developed with system opti-mization perspective. Each kind of products has an individual cost function and, at the same time,contributes to its own and other product's cost function in an individual way. The well-known equi-librium algorithm is extended to nd system optimization pattern for such multiproduct supply chainnetwork.
Model predictive control-based scheduler for repetitive discrete event systems with capacity constraints
Authors: Goto Hiroyuki
Published: July 2013

A model predictive control-based scheduler for a class of discrete event systems is designed and developed. We focus on repetitive, multiple-input, multiple-output, and directed acyclic graph structured systems on which capacity constraints can be imposed. The target system’s behaviour is described by linear equations in max-plus algebra, referred to as state-space representation. Assuming that the system’s performance can be improved by paying additional cost, we adjust the system parameters and determine control inputs for which the reference output signals can be observed. The main contribution of this research is twofold, 1: For systems with capacity constraints, we derived an output prediction equation as functions of adjustable variables in a recursive form, 2: Regarding the construct for the system’s representation, we improved the structure to accomplish general operations which are essential for adjusting the system parameters. The result of numerical simulation in a later section demonstrates the effectiveness of the developed controller.
Uncertainty Quantification: A Stochastic Method for Heat Transfer Prediction Using LES
Authors: Carnevale M. , Montomoli F. , D’Ammaro A. , Salvadori S. , Martelli F.
Published: June 2013

In computational fluid dynamics (CFD), it is possible to identify namely two uncertainties: epistemic, related to the turbulence model, and aleatoric, representing the random-unknown conditions such as the boundary values and or geometrical variations. In the field of epistemic uncertainty, large eddy simulation (LES and DES) is the state of the art in terms of turbulence closures to predict the heat transfer in internal channels. The problem is still unresolved for the stochastic variations and how to include these effects in the LES studies. In this paper, for the first time in literature, a stochastic approach is proposed to include these variations in LES. By using a classical uncertainty quantification approach, the probabilistic collocation method is coupled to numerical large eddy simulation (NLES) in a duct with pin fins. The Reynolds number has been chosen as a stochastic variable with a normal distribution. The Reynolds number is representative of the uncertainties associated with the operating conditions, i.e., velocity and density, and geometrical variations such as the pin fin diameter. This work shows that assuming a Gaussian distribution for the Reynolds number of ±25%, it is possible to define the probability to achieve a specified heat loading under stochastic conditions, which can affect the component life by more than 100%. The same method, applied to a steady RANS, generates a different level of uncertainty. New methods have been proposed based on the different level of aleatoric uncertainties which provides information on the epistemic uncertainty. This proves, for the first time, that the uncertainties related to the unknown conditions, aleatoric, and those related to the physical model, epistemic, are strongly interconnected. This result, which is idealized for this specific issue, can be extrapolated, and has direct consequences in uncertainty quantification science and not only in the gas turbine world.
The Effect of Tip Leakage Vortex for Operating Range Enhancement of Centrifugal Compressor
Authors: Tomita Isao , Ibaraki Seiichi , Furukawa Masato , Yamada Kazutoyo
Published: June 2013

Recently, the application of turbochargers is increasing because they are effective in improving fuel consumption of engines. One of the most important turbocharger characteristics is compressor operating range, since it has been used in various driving patterns with the advent of variable geometry turbochargers. Owing to the complicated phenomena, such as rotating stall occurring at low flow rate condition, flow analysis is very difficult and details of flow structure have not been fully understood for a long time since the early 1970s. In this study, two compressors with different operating range width were investigated with experimental and computational flow analysis. In the compressor with narrow operating range, the amplitude of blade passing pressure fluctuation decreases rapidly and rotating stall occurs near surging. On the other hand, in the compressor with wide operating range, the blockage by the tip leakage vortex breakdown play a role in stabilizing the flow field and keeping up a high performance even at low flow rates.
A Comparison of Three Low Pressure Turbine Designs
Authors: Wakelam Christian T. , Hoeger Martin , Niehuis Reinhard
Published: June 2013

As part of the current research, three low pressure turbine (LPT) geometries—which were designed with a common pitch, axial chord, inlet angle, and exit Mach number and to create the same nominal level of turning—are compared. Each of the LPT cascades was investigated under a range of Reynolds numbers, exit Mach numbers, and under the influence of a moving bar wake generator. Profile static pressure distributions, wake traverses at 5% and 40% axial chord downstream of the trailing edge, and suction side boundary layer traverses were used to compare the performance of the three designs. The total pressure losses are strongly dependent on both the maximum velocity location as well as the diffusion on the suction surface. The importance of the behavior of the pressure surface boundary layer turned out to be negligible in comparison. Cases with equivalent operating Reynolds number and suction side diffusion level are compared in terms of the total pressure losses that are generated. It is shown that a relationship between loss and suction side maximum velocity location exists. An optimum suction side maximum velocity location depends on the Reynolds number, diffusion factor, and wake passing frequency.
Optimization of a U-Bend for Minimal Pressure Loss in Internal Cooling Channels—Part I: Numerical Method
Authors: Verstraete Tom , Coletti Filippo , Bulle Jérémy , Vanderwielen Timothée , Arts Tony
Published: June 2013

This two-part paper addresses the design of a U-bend for serpentine internal cooling channels optimized for minimal pressure loss. The total pressure loss for the flow in a U-bend is a critical design parameter, as it augments the pressure required at the inlet of the cooling system, resulting in a lower global efficiency. In this first part of the paper, the design methodology of the cooling channel is presented. The minimization of the total pressure loss is achieved by means of a numerical optimization method that uses a metamodel-assisted differential evolution algorithm in combination with an incompressible Navier–Stokes solver. The profiles of the internal and external side of the bend are parameterized using piece-wise Bezier curves. This allows for a wide variety of shapes, respecting the manufacturability constraints of the design. The pressure loss is computed by the Navier–Stokes solver, which is based on a two-equation turbulence model and is available from the open source software OpenFOAM. The numerical method predicts an improvement of 36% in total pressure drop with respect to a circular U-bend, mainly due to the reduction of the separated flow region along the internal side of the bend. The resulting design is subjected to experimental validation, presented in Part II of the paper.
Influence of Film Cooling Hole Angles and Geometries on Aerodynamic Loss and Net Heat Flux Reduction
Authors: Lim Chia Hui , Pullan Graham , Ireland Peter
Published: June 2013

Turbine design engineers have to ensure that film cooling can provide sufficient protection to turbine blades from the hot mainstream gas, while keeping the losses low. Film cooling hole design parameters include inclination angle (α), compound angle (β), hole inlet geometry, and hole exit geometry. The influence of these parameters on aerodynamic loss and net heat flux reduction is investigated, with loss being the primary focus. Low-speed flat plate experiments have been conducted at momentum flux ratios of IR = 0.16, 0.64, and 1.44. The film cooling aerodynamic mixing loss, generated by the mixing of mainstream and coolant, can be quantified using a three-dimensional analytical model that has been previously reported by the authors. The model suggests that for the same flow conditions, the aerodynamic mixing loss is the same for holes with different α and β but with the same angle between the mainstream and coolant flow directions (angle κ). This relationship is assessed through experiments by testing two sets of cylindrical holes with different α and β: one set with κ = 35 deg, and another set with κ = 60 deg. The data confirm the stated relationship between α, β, κ and the aerodynamic mixing loss. The results show that the designer should minimize κ to obtain the lowest loss, but maximize β to achieve the best heat transfer performance. A suggestion on improving the loss model is also given. Five different hole geometries (α = 35.0 deg, β = 0 deg) were also tested: cylindrical hole, trenched hole, fan-shaped hole, D-Fan, and SD-Fan. The D-Fan and the SD-Fan have similar hole exits to the fan-shaped hole but their hole inlets are laterally expanded. The external mixing loss and the loss generated inside the hole are compared. It was found that the D-Fan and the SD-Fan have the lowest loss. This is attributed to their laterally expanded hole inlets, which lead to significant reduction in the loss generated inside the holes. As a result, the loss of these geometries is ≈ 50% of the loss of the fan-shaped hole at IR = 0.64 and 1.44.
Boundary Layer Control on a Low Pressure Turbine Blade by Means of Pulsed Blowing
Authors: Mack Marion , Niehuis Reinhard , Fiala Andreas , Guendogdu Yavuz
Published: June 2013

The current work investigates the performance benefits of pulsed blowing with frequencies up to 10 kHz on a highly loaded low pressure turbine (LPT) blade. The influence of blowing position and frequency on the boundary layer and losses are investigated. Pressure profile distribution measurements and midspan wake traverses are used to assess the effects on the boundary layer under a wide range of Reynolds numbers from 50,000 to 200,000 at a cascade exit Mach number of 0.6 under steady as well as periodically unsteady inflow conditions. High-frequency blowing at sufficient amplitudes is achieved with the use of fluidic oscillators. The integral loss coefficient calculated from wake traverses is used to assess the optimum pressure ratio driving the fluidic oscillators. The results show that pulsed blowing with fluidic oscillators can significantly reduce the profile losses of the highly loaded LPT blade T161 with a moderate amount of air used in a wide range of Reynolds numbers under both steady and unsteady inflow conditions.
Overall and Adiabatic Effectiveness Values on a Scaled Up, Simulated Gas Turbine Vane
Authors: Dees Jason E. , Bogard David G. , Ledezma Gustavo A. , Laskowski Gregory M.
Published: June 2013

Recent advances in computational power have made conjugate heat transfer simulations of fully conducting, film cooled turbine components feasible. However, experimental data available with which to validate conjugate heat transfer simulations is limited. This paper presents experimental measurements of external surface temperature on the suction side of a scaled up, fully conducting, cooled gas turbine vane. The experimental model utilizes the matched Bi method, which produces nondimensional surface temperature measurements that are representative of engine conditions. Adiabatic effectiveness values were measured on an identical near adiabatic vane with an identical geometry and cooling configuration. In addition to providing a valuable data set for computational code validation, the data shows the effect of film cooling on the surface temperature of a film cooled part. As expected, in nearly all instances, the addition of film cooling was seen to decrease the overall surface temperature. However, due to the effect of film injection causing early boundary layer transition, film cooling at a high momentum flux ratio was shown to actually increase surface temperature over 0.35 < s/C < 0.45.
Experimental and Numerical Crossover Jet Impingement in a Rib-Roughened Airfoil Trailing-Edge Cooling Channel
Authors: Taslim M. E. , Fong M. K. H.
Published: June 2013

Local and average heat transfer coefficients were measured in a test section simulating a rib-roughened trailing edge cooling cavity of a turbine airfoil. The test rig was made up of two adjacent channels, each with a trapezoidal cross sectional area. The first channel, simulating the cooling cavity adjacent to the trailing-edge cavity, supplied the cooling air to the trailing-edge channel through a row of racetrack-shaped slots on the partition wall between the two channels. Eleven crossover jets, issued from these slots entered the trailing-edge channel, impinged on eleven radial ribs and exited from a second row of race-track shaped slots on the opposite wall in staggered or inline arrangement. Two jet angles of 0 deg and 5 deg and a range of jet Reynolds number from 10,000 to 35,000 were tested and compared. The numerical models contained the entire trailing-edge and supply channels with all slots and ribs to simulate exactly the tested geometries. They were meshed with all-hexa structured mesh of high near-wall concentration. A pressure-correction based, multiblock, multigrid, unstructured/adaptive commercial software was used in this investigation. The realizable k-ε turbulence model was employed in combination with an enhanced wall treatment approach for the near wall regions. Boundary conditions identical to those of the experiments were applied and several turbulence model results were compared. The numerical analyses also provided the share of each crossover and each exit hole from the total flow for different geometries. The major conclusions of this study were: (a) except for the first and last cross-flow jets, which had different flow structures, other jets produced the same heat transfer results on their target surfaces; (b) tilted crossover jets produced higher heat transfer coefficients on the target surface towards which they were tilted and lower values on the opposite surface, and (c) the numerical predictions of impingement heat transfer coefficients were in good agreement with the measured values for most cases thus CFD could be considered a viable tool in airfoil cooling circuit designs.
Helicopter Ground Resonance Phenomenon With Blade Stiffness Dissimilarities: Experimental and Theoretical Developments
Authors: Sanches Leonardo , Michon Guilhem , Berlioz Alain , Alazard Daniel
Published: June 2013

Recent works have studied ground resonance in helicopters under the aging or damage effects. Indeed, blade lead-lag stiffness may vary randomly with time and differ from blade to blade. The influence of stiffness dissimilarities between blades on the stability of the ground resonance phenomenon was determined through numerical investigations into the periodic equations of motion, treated using Floquet's theory. A stability chart highlights the appearance of new instability zones as a function of the perturbation introduced on the lead-lag stiffness of one blade. In order to validate the theoretical results, a new experimental setup was designed and developed. The ground resonance instabilities were investigated using different rotors and the boundaries of stability were determined. A good correlation between both theoretical and experimental results was obtained and the new instability zones, found in asymmetric rotors, were verified experimentally. The temporal responses of the measured signals highlighted the exponential divergence in the instability zones.
Application of Smoothed Particle Hydrodynamics to Full-Film Lubrication
Authors: Kyle Jonathan P. , Terrell Elon J.
Published: July 2013

An in-house solver was created in order to simulate hydrodynamic lubrication utilizing smoothed particle hydrodynamics (SPH). SPH is a meshfree, Lagrangian, particle-based method that can be used to solve continuum problems. In this study, transient hydrodynamic lubrication in a pad bearing geometry was modeled utilizing the SPH method. The results were validated by comparison to computational fluid dynamics (CFD) and an analytical solution provided by lubrication theory. Results for the pressure distribution between SPH and CFD were agreeable while lubrication theory failed to capture any inertial effects of the fluid. Velocity profile comparisons differed slightly between all three methods. However, since smoothed particle methods have been shown to have the advantage of being able to model large deformations, as well as allowing easy definitions of fluid-solid interfaces, they can be useful tools for complex problems in tribology.
Effects of Water Contamination of Lubricants on Hydrodynamic Lubrication: Rheological and Thermal Modeling
Authors: Harika Elias , Bouyer Jean , Fillon Michel , Hélène Mathieu
Published: July 2013

Even if water has more favorable thermal characteristics than oil, its use in the realm of bearings is still restricted to some rare applications. Moreover, the presence of water in lubricating circuits is seen as not at all desirable. The contamination of oil by water results in dangerous effects on lubrication. In relation to this, the study of thermal enhancement that this contamination can provide is seen to be insignificant. The literature demonstrates the damaging effects of this type of contamination. However, the existing studies are commonly based on an analysis of the results obtained after a bearing failure. The present study evaluates the instantaneous effect of the water-oil mixture on hydrodynamic lubrication for significant levels of water concentration, up to 10% by mass. The aim of the work is to identify the conditions for which the presence of water is detrimental in lubrication. Such conditions could then be avoided and a new generation of lubrication circuits could be designed to be immune against water contamination. Moreover, any positive effects of water contamination on lubrication deserve to be studied, the possibility being that new lubricant concepts might emerge. Thus, the rheological behavior and thermal characteristics of the mixture (density, specific heat, and thermal conductivity) were numerically modeled and simulations of bearings operating with this mixture were performed. The lubrication characteristics were also measured on a tilting pad thrust bearing, similar effects to those obtained numerically being observed. The presence of water has a slight effect on lubrication, which is nevertheless recognized to amount to an improvement in the lubrication characteristics. In fact, it is found that pure oil could be replaced by a water-in-oil emulsion having the same viscosity. In this case, the film thickness and the friction coefficient will be weakly modified, whereas the bearing will run at a lower temperature. From the point of view of safety, this indicates a significant advantage in operating conditions.
TCR-Ligand
k
off
Rate Correlates with the Protective Capacity of Antigen-Specific CD8
+
T Cells for Adoptive Transfer
Authors: Nauerth Magdalena , Weißbrich Bianca , Knall Robert , Franz Tobias , Dössinger Georg , Bet Jeannette , Paszkiewicz Paulina J. , Pfeifer Lukas , Bunse Mario , Uckert Wolfgang , Holtappels Rafaela , Gillert-Marien Dorothea , Neuenhahn Michael , Krackhardt Angela , Reddehase Matthias J. , Riddell Stanley R. , Busch Dirk H.
Published: July 2013

A
Strep
tamer-based
k
off
rate assay identifies T cells with high protective capacity for the adoptive transfer.
AMP
v.
Myriad
: A Surgical Strike on Blockbuster Business Models
Authors: Gold Richard E. , Cook-Deegan Robert , Bubela Tania
Published: July 2013

The U.S. Supreme Court’s decision in the Myriad Genetics case will promote translation of genetics-based diagnostics while preserving patent protection for other biomedical products.
Modifying Genetic Disease
Authors: Gregg Christopher
Published: July 2013

A new study identifies modifier genes for ataxin 1 in spinocerebellar ataxia and a strategy for treating such genetic diseases.
Paragonimiasis Acquired in the United States: Native and Nonnative Species
Authors: Diaz James H.
Published: July 2013

Paragonimiasis is a parasitic lung infection caused by lung flukes of the genus
Paragonimus
, with most cases reported from Asia and caused by
P. westermani
following consumption of raw or undercooked crustaceans. With the exception of imported
P. westermani
cases in immigrants, in travelers returning from areas of disease endemicity, and in clusters of acquired cases following consumption of imported Asian crabs, human paragonimiasis caused by native lung flukes is rarely described in the United States, which has only one indigenous species of lung fluke,
Paragonimus kellicotti
. Clinicians should inquire about the consumption of raw or undercooked freshwater crabs by immigrants, expatriates, and returning travelers, and the consumption of raw or undercooked crayfish in U.S. freshwater river systems where
P. kellicotti
is endemic when evaluating patients presenting with unexplained fever, cough, rales, hemoptysis, pleural effusions, and peripheral eosinophilia. Diagnostic evaluation by specific parasitological, radiological, serological, and molecular methods will be required in order to differentiate paragonimiasis from tuberculosis, which is not uncommon in recent Asian immigrants. All cases of imported and locally acquired paragonimiasis will require treatment with oral praziquantel to avoid any potential pulmonary and cerebral complications of paragonimiasis, some of which may require surgical interventions.