bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aerothermal Performance of Shroudless Turbine Blade Tips With Effects of Relative Casing Motion
Authors: Virdi A. S. , Zhang Q. , He L. , Li H. D. , Hunsley R. 
Published: February 2014

Recent work has indicated qualitatively different heat transfer characteristics between a transonic blade tip and a subsonic one. High resolution experimental data can be acquired for blade tip heat transfer research using a high speed linear cascade. While recognising an important role played by the cascade tests in validating computational models at the same conditions, some questions arise in relation to the effects of relative casing motion:
1) Does the relative casing movement change the main flow physics influencing the blade tip aerothermal performance?
2) Can a cascade set up with stationary casing wall rank different designs?
3) How do the effects of the casing motion depend on tip design configurations?
A combined experimental and CFD study on several high pressure blade tip configurations is conducted to address these issues.
Firstly, extensive experimental tests with aerodynamic loss and heat transfer measurement in a high speed linear cascade have been carried out for a squealer tip configuration at engine representative aerodynamic conditions. A systematic validation of the CFD solver (Rolls-Royce HYDRA) is presented, which serves as a basis for the computational analyses of the effects of the relative casing motion.
Two tip configurations (squealer and flat tip) at three tip gaps (0.5%, 1.0%, 1.5% span) are analysed. The main aerodynamic impact of the casing motion is seen to promote the passage vortex, which consequently supresses the pitchwise reach of the tip leakage vortex. Inside the tip gap, the behaviour is dominated by the extra wall friction in relation of the inertia of the bulk fluid through the gap. As such, the moving casing effect is particularly strong for the flat tip at a small tip gap. For the large and medium tip gaps, both stationary and moving casing results are shown to consistently capture the trends in overall aerothermal performances.
The present results confirm that even with relative casing motion, there is still a significant portion of transonic flow over a blade tip. For both the stationary and moving casing cases, the gap dependence of the over-tip heat transfer shows opposite trends for the transonic and subsonic regions respectively. The gap dependence of the blade tip heat transfer is shown to be clearly dependent on tip geometry configurations, as the bulk flow in a squealer cavity is subsonic regardless of the tip gap size, whilst the local flow state over a flat tip is much more responsive to the change of gap size.
Leakage Flow Impact on High Aspect Ratio Steam Turbine Reaction Blades
Authors: Nettis Leonardo , Lombardi Luca 
Published: February 2014

The steam turbine stage efficiency is significantly affected by clearance losses due to leakage flow re-entering the main flowpath. The impact, in terms of delta of efficiency Δη, is usually assessed by assuming the proportionality Δη = K × (mLeak/mMain), being mLeak/mMain the fraction of the leakage flow relative to the main mass flow rate and K the constant evaluated by experimental and numerical evidence. Several studies are present in the literature concerning low aspect ratio blades, where this constant K is found to be equal to 1, or even higher for very low percentage leakage massflow.
The main purpose of the current work consists of assessing this factor in the case of steam turbine reaction blades of the HP sector, characterized by a high aspect ratio. A numerical analysis has been set up where the detailed 3D geometry of two HP stages has been modeled and simulated by a 3D-CFD approach. Then a sensitivity analysis has been carried out by varying the leakage flows coming from stator and rotor labyrinth seals, realized by changing the radial gap of the clearance. This analysis has been repeated for several working points in order to obtain the leakage impact in the whole operating range of the reaction stages. The K factor comes out to be close to 0.8 at design point, whilst it increases up to 1 for highly loaded off-design condition.
Development of New Abradable/Abrasive Sealing Systems for Clearance Control in Gas Turbines
Authors: Scrinzi Erica , Giovannetti Iacopo , Sheng Nuo , Leblanc Luc 
Published: February 2014

Abradable/abrasive sealing systems are currently used in gas turbines to reduce the blade tip gas leakage and consequently improve the turbine efficiency. The coatings selection is directly related to the section in which they are used. Seal systems for hot gas paths are primarily required to withstand high temperature. The abradable coating should be easily removed by the tip blade without causing significant blade wear, whereas the blades should have sufficient cutting capabilities. Durability properties, such as erosion resistance, are also required.
Owing to their temperature capabilities, porous ceramic coatings are successfully used as abradable coatings. Although they are characterized by good abradability properties, their resistance to environmental attacks, such as solid particle erosion, is limited by the porous microstructure which negatively affects their service life.
It is apparent that durability and abradability are the main targets to be simultaneously achieved for ensuring longer service life and improved efficiency. The present work is aimed at developing new abradable/abrasive coatings pairs able to ensure both the durability performances of the coatings and good abradability properties.
Three ceramic abradable coatings with DVC and porous microstructure have been studied. The down-selection process has been carried out by considering the microstructure, the hardness, the tensile adhesion strength, the erosion resistance, and the furnace cycle test resistance.
A composite coating made by NiCoCrAlY matrix containing abrasive grits applied by electrolytic process was selected as abrasive material system. The abrasive grits (patent application in process by GE Oil&Gas) consists of a mixture of ceramic particles. These grits ensure both short-term cutting capability and thermal stability, assuring the clearance maintenance over time.
The abradability of the seal system was assessed by a properly designed test, namely Rub Rig test, which simulates the blade incursion in the abradable coating. Surface patterns on abradable coating were also considered to further enhance the abradability. Engine tests are foreseen for assessing the service behavior of this seal system.
Hepatitis A Virus Adaptation to Cellular Shutoff Is Driven by Dynamic Adjustments of Codon Usage and Results in the Selection of Populations with Altered Capsids
Authors: Costafreda M. Isabel , Pérez-Rodriguez Francisco J. , D'Andrea Lucía , Guix Susana , Ribes Enric , Bosch Albert , Pintó Rosa M. 
Published: February 2014

ABSTRACT
Hepatitis A virus (HAV) has a highly biased and deoptimized codon usage compared to the host cell and fails to inhibit host protein synthesis. It has been proposed that an optimal combination of abundant and rare codons controls the translation speed required for the correct capsid folding. The artificial shutoff host protein synthesis results in the selection of variants containing mutations in the HAV capsid coding region critical for folding, stability, and function. Here, we show that these capsid mutations resulted in changes in their antigenicity; in a reduced stability to high temperature, low pH, and biliary salts; and in an increased efficacy of cell entry. In conclusion, the adaptation to cellular shutoff resulted in the selection of large-plaque-producing virus populations.

IMPORTANCE
HAV has a naturally deoptimized codon usage with respect to that of its cell host and is unable to shut down the cellular translation. This fact contributes to the low replication rate of the virus, in addition to other factors such as the highly inefficient internal ribosome entry site (IRES), and explains the outstanding physical stability of this pathogen in the environment mediated by a folding-dependent highly cohesive capsid. Adaptation to artificially induced cellular transcription shutoff resulted in a redeoptimization of its capsid codon usage, instead of an optimization. These genomic changes are related to an overall change of capsid folding, which in turn induces changes in the cell entry process. Remarkably, the adaptation to cellular shutoff allowed the virus to significantly increase its RNA uncoating efficiency, resulting in the selection of large-plaque-producing populations. However, these populations produced much-debilitated virions.
Receptor Variation and Susceptibility to Middle East Respiratory Syndrome Coronavirus Infection
Authors: Barlan Arlene , Zhao Jincun , Sarkar Mayukh K. , Li Kun , McCray Paul B. , Perlman Stanley , Gallagher Tom 
Published: February 2014

ABSTRACT
The Middle East respiratory syndrome coronavirus (MERS-CoV) recently spread from an animal reservoir to infect humans, causing sporadic severe and frequently fatal respiratory disease. Appropriate public health and control measures will require discovery of the zoonotic MERS coronavirus reservoirs. The relevant animal hosts are liable to be those that offer optimal MERS virus cell entry. Cell entry begins with virus spike (S) protein binding to DPP4 receptors. We constructed chimeric DPP4 receptors that have the virus-binding domains of indigenous Middle Eastern animals and assessed the activities of these receptors in supporting S protein binding and virus entry. Human, camel, and horse receptors were potent and nearly equally effective MERS virus receptors, while goat and bat receptors were considerably less effective. These patterns reflected S protein affinities for the receptors. However, even the low-affinity receptors could hypersensitize cells to infection when an S-cleaving protease(s) was present, indicating that affinity thresholds for virus entry must be considered in the context of host-cell proteolytic environments. These findings suggest that virus receptors and S protein-cleaving proteases combine in a variety of animals to offer efficient virus entry and that several Middle Eastern animals are potential reservoirs for transmitting MERS-CoV to humans.

IMPORTANCE
MERS is a frequently fatal disease that is caused by a zoonotic CoV. The animals transmitting MERS-CoV to humans are not yet known. Infection by MERS-CoV requires receptors and proteases on host cells. We compared the receptors of humans and Middle Eastern animals and found that human, camel, and horse receptors sensitized cells to MERS-CoV infection more robustly than goat and bat receptors. Infection susceptibility correlated with affinities of the receptors for viral spike proteins. We also found that the presence of a cell surface lung protease greatly increases susceptibility to MERS-CoV, particularly in conjunction with low-affinity receptors. This cataloguing of human and animal host cell factors allows one to make inferences on the distribution of MERS-CoV in nature.
Boosting Functional Avidity of CD8
+
T Cells by Vaccinia Virus Vaccination Depends on Intrinsic T-Cell MyD88 Expression but Not the Inflammatory Milieu
Authors: Hu Zhidong , Wang Jing , Wan Yanmin , Zhu Lingyan , Ren Xiaonan , Qiu Sugan , Ren Yanqin , Yuan Songhua , Ding Xiangqing , Chen Jian , Qiu Chenli , Sun Jun , Zhang Xiaoyan , Xiang Jim , Qiu Chao , Xu Jianqing 
Published: February 2014

ABSTRACT

T-cell functional avidity is a crucial determinant for efficient pathogen clearance. Although recombinant DNA priming coupled with a vaccinia-vectored vaccine (VACV) boost has been widely used to mount robust CD8
+
T-cell responses, how VACV boost shapes the properties of memory CD8
+
T cells remains poorly defined. Here, we characterize the memory CD8
+
T cells boosted by VACV and demonstrate that the intrinsic expression of MyD88 is critical for their high functional avidity. Independent of selection of clones with high-affinity T-cell receptor (TCR) or of enhanced proximal TCR signaling, the VACV boost significantly increased T-cell functional avidity through a decrease in the activation threshold. VACV-induced inflammatory milieu is not sufficient for this improvement, as simultaneous administration of the DNA vaccine and mock VACV had no effects on the functional avidity of memory CD8
+
T cells. Furthermore, reciprocal adoptive transfer models revealed that the intrinsic MyD88 pathway is required for instructing the functional avidity of CD8
+
T cells boosted by VACV. Taking these results together, the intrinsic MyD88 pathway is required for the high functional avidity of VACV-boosted CD8
+
T cells independent of TCR selection or the VACV infection-induced MyD88-mediated inflammatory milieu.

IMPORTANCE
Functional avidity is one of the crucial determinants of T-cell functionality. Interestingly, although it has been demonstrated that a DNA prime-VACV boost regimen elicits high levels of T-cell functional avidity, how VACV changes the low avidity of CD8
+
T cells primed by DNA into higher ones
in vivo
is less defined. Here, we proved that the enhancement of CD8
+
T cell avidity induced by VACV boost is mediated by the intrinsic MyD88 pathway but not the MyD88-mediated inflammatory milieu, which might provide prompts in vaccine design.
Jejunal perforation: a rare presentation of B-cell lymphoma
Authors: Santharam V , Kumar P , Lee L Y W 
Published: February 2014

SummaryA 42-year-old man who was being treated for pneumonia developed severe, sudden-onset abdominal pain with features of shock and peritonism. The clinical picture combined with radiological investigations raised suspicion of a bowel perforation necessitating urgent surgical review and emergency laparotomy. This diagnosed a jejunal perforation with abnormal lymph nodes. Histological examination confirmed diffuse large B-cell lymphoma. The patient was subsequently started on a course of chemotherapy. While gastrointestinal perforation secondary to antilymphoma treatment is a well-recognised complication, primary perforation caused by the lymphoma itself must always be considered.
Antithrombotic properties of rafigrelide: a phase 1, open-label, non-randomised, single-sequence, crossover study
Authors: Balasubramaniam Karthik , Viswanathan Girish , Dragone Jeff , Grose-Hodge Rachael , Martin Patrick , Troy Steve , Preston Peter , Zaman Azfar G. 
Published: February 2014

SummaryPlatelets play a central role in atherothrombotic events. We investigated the effect of a novel platelet-lowering agent, rafigrelide, on thrombus formation and characteristics. In this phase 1, open-label, non-randomised, single-sequence, crossover study, healthy male volunteers received rafigrelide for 14 days (Period 1). Following a ≥6-week washout period, they then received rafigrelide + acetylsalicylic acid (ASA) for 14 days (Period 2). Thrombus formation was assessed ex vivo using the Badimon perfusion chamber, and thrombus characteristics were assessed using thromboelastography. A total of 15 volunteers were enrolled in the study and were assigned to Panel A or Panel B, which had different schedules of assessments. In Panel A, after treatment with rafigrelide alone (Period 1), mean (± standard deviation) platelet count was reduced from 283 (± 17) × 109/l at Day 1, to 125 (± 47) × 109/l at Day 14 (n=6) and thrombus area reduced under high and low shear conditions. Reductions in thrombus area under high shear conditions correlated with reductions in platelet count (r2=0.11, p=0.022; n=12). Rafigrelide treatment prolonged clot formation time and reduced clot strength. The addition of ASA to rafigrelide (Period 2) had no additional effect on platelet count or thrombus area under high or low shear conditions. Similar results were seen in Panel B for all parameters. The most common adverse events (≥3 participants per period) were thrombocytopenia and headache. While confirming the platelet-lowering effects of rafigrelide, this early phase study also indicates that rafigrelide has antithrombotic properties under both high and low shear conditions.
Wood Structural Anisotropy Estimated by Acoustic Invariants
Authors: Bucur Voichita 
Published: February 2014

Wood anisotropy is induced by the specific deposition of anatomical elements during the life of the tree. The anisotropy becomes evident when acoustical properties are measured in the different main symmetry directions.The first approach for the estimation of wood anisotropy was to calculate the ratios of longitudinal and shear velocities in natural symmetry directions. The modeling of wood structure is required in order to relate the anatomical structure to the acoustical behaviour of wood.The second approach for wood anisotropy interpretation was to compute acoustic invariants and to average them. Considering that those quantities are insensitive to the direction of propagation, they can act as references for anisotropy investigation. Combining the values of invariants in the three main symmetry planes yields a single global value that characterises each species.Values of invariants for 15 species (conifers and broadleaves) are given.
A Multilevel Analysis of the Impacts of Services Provided by the U.K. Employment Retention and Advancement Demonstration
Authors: Dorsett Richard , Robins Philip K. 
Published: February 2014

Background: The United Kingdom Employment Retention and Advancement (U.K. ERA) demonstration was the largest and most comprehensive social experiment ever conducted in the United Kingdom. It examined the extent to which a combination of postemployment advisory support and financial incentives could help lone parents on welfare to find sustained employment with prospects for advancement. ERA was experimentally tested across more than 50 public employment service offices and, within each office, individuals were randomly assigned to either a program (or treatment) group (eligible for ERA) or a control group (not eligible). Method: This article presents the results of a multilevel nonexperimental analysis that examines the variation in office-level impacts and attempts to understand what services provided in the offices tend to be associated with impacts. Result: The analysis suggests that impacts were greater in offices that emphasized in-work advancement, support while working and financial bonuses for sustained employment, and also in those offices that assigned more caseworkers to ERA participants. Offices that encouraged further education had smaller employment impacts. Conclusion: Plausible results are obtained identifying those particular implementation features that tended to be linked to stronger impacts of ERA. The methodology employed also allows the identification of which services are associated with employment and welfare receipt of control families receiving benefits under the traditional New Deal for Lone Parent program.
Improvement of functional independence of patients with acute schizophrenia through early occupational therapy: a pilot quasi-experimental controlled study
Authors: Tanaka Chito , Yotsumoto Kayano , Tatsumi Eri , Sasada Toru , Taira Masaru , Tanaka Kiwamu , Maeda Kiyoshi , Hashimoto Takeshi 
Published: February 2014

Objective: To clarify whether early occupational therapy for patients with acute schizophrenia improves their functional independence. Design: Quasi-experimental controlled study. Setting: A university hospital in Japan. Subjects: Forty-six out of 85 eligible patients with schizophrenia. Intervention: Participants were allocated into an intervention group or a control group according to the month of admission. Activities in one-on-one and mainly non-verbal occupational therapy were provided for the intervention group immediately after admission, and not for the control group. Main measures: Functional independence was measured using the Functional Independence Measure (FIM), at admission, at one month and at three months after admission. Psychiatric symptoms were also measured by the Brief Psychiatric Rating Scale. Results: Patients in both groups showed improved FIM total scores at one month and three months after admission. In the intervention group, the medians (interquartile ranges) were 89.0 (44.5) at admission, 113.0 (18.5) at one month, and 121.0 (6.5) at three months. In the control group, they were 88.0 (32.0), 107.0 (39.5), and 111.0 (17.0). At three months, the total FIM scores were significantly higher in the intervention group than in the control group ( p = 0.016). In the FIM cognitive domain, the scores were significantly higher in the intervention group than in the control group at one month ( p = 0.038) and, three months ( p = 0.012). Both groups showed improvement in Brief Psychiatric Rating Scale total scores, while no significant differences were observed between the groups at any points. Conclusion: The results suggest that early occupational therapy may improve functional independence in patients with acute schizophrenia.
Perfusion patterns in migraine with aura
Authors: Förster Alex , Wenz Holger , Kerl Hans U , Brockmann Marc A , Groden Christoph 
Published: February 2014

Objectives Migraine with aura is a common neurological disorder, and differentiation from transient ischemic attack or stroke based on clinical symptoms may be difficult. Methods From an MRI report database we identified 33 patients with migraine with aura and compared these to 33 age-matched ischemic stroke patients regarding perfusion patterns on perfusion-weighted imaging (PWI)-derived maps: time to peak (TTP), mean transit time (MTT), and cerebral blood flow and volume (CBF, CBV). Results In 18/33 (54.5%) patients with migraine with aura, TTP showed areas of hypoperfusion, most of these not limited to the territory of a specific artery but affecting two or more vascular territories. In patients with migraine with aura, TTP (1.09 ± 0.05 vs. 1.47 ± 0.40, p < 0.001) and MTT ratios (1.01 ± 0.10 vs. 1.19 ± 0.21, p = 0.003) were significantly lower compared to patients with ischemic stroke. In contrast to this, CBF and CBV ratios did not differ significantly between both groups. Conclusions Migraine aura is usually associated with a perfusion deficit not limited to a specific vascular territory, and only a moderate increase of TTP. Thus, hypoperfusion restricted to a single vascular territory in combination with a marked increase of TTP or MTT may be regarded as atypical for migraine aura and suggestive of acute ischemic stroke.
Prevalence and prognostic value of headache on early mortality in acute stroke: The Dijon Stroke Registry
Authors: Abadie Victor , Jacquin Agnès , Daubail Benoit , Vialatte Anne‐Laure , Lainay Claire , Durier Jérôme , Osseby Guy‐Victor , Giroud Maurice , Béjot Yannick 
Published: February 2014

Objective To evaluate the prevalence of headache at onset and its association with 1-month mortality in stroke patients. Methods All patients with stroke in Dijon, France (2006–2011), were prospectively identified using a population-based registry. Cox regression models were used to evaluate the association between headache and 30-day all-cause mortality. Results Among 1411 stroke patients, data about headache were obtained for 1391 (98.6%) of whom 1185 had an ischemic stroke (IS), 201 had an intracerebral hemorrhage (ICH) and five had a stroke of undetermined etiology. Headache was found in 253 (18.2%) patients and was more frequent in those with ICH than in those with IS (46.3% vs 13.5%, p < 0.001). Overall 30-day mortality was 11.7%, and was greater for patients with than those without headache (17.0% vs 10.5%, unadjusted HR 1.70; 95% CI 1.20–2.41, p = 0.003). In multivariable analysis, an association between headache and 30-day mortality was observed (HR 1.51; 95% CI 1.02–2.25, p = 0.042). In stratified analyses, headache was associated with 30-day mortality in ICH (HR 2.09; 95% CI 1.18–3.71, p = 0.011) but not in IS (HR 1.01; 95% CI 0.53–1.92, p = 0.97). Conclusion Headache at stroke onset is associated with a higher risk of early mortality in patients with ICH.