bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of stem cell marker nestin and its correlation with vascular endothelial growth factor and microvascular density in ependymomas
Authors: Nambirajan Aruna , Sharma Mehar C. , Gupta Rakesh Kumar , Suri Vaishali , Singh Manmohan , Sarkar Chitra 
Published: November 2013

BackgroundEpendymomas are relatively rare glial tumours, whose pathogenesis is not well elucidated. They are enigmatic tumours that show site‐specific differences in their biological behaviour. Recent studies have hypothesized that ependymoma cancer stem cells (CSCs) are derived from radial glia and express stem cell markers such as nestin, which is associated with a poor prognosis. CSCs reside in ‘vascular niches’, where endothelial cells and molecular signals like vascular endothelial growth factor (VEGF) play an important role in their survival. Studies analysing VEGF expression in ependymomas showed that ependymal vascular proliferation is less sensitive to induction by VEGF, questioning the possible beneficial effect of anti‐VEGF therapy in ependymomas. We aimed to study nestin and VEGF immunoexpression in ependymomas, correlate them with clinicopathological parameters and reveal a role for VEGF in ependymomas that extends beyond the context of tumour angiogenesis.MethodsWe analysed 126 cases of ependymomas of different grades and locations for nestin and VEGF immunoexpression. Endothelial cells were labelled with CD34. Vascular patterns and microvascular density was determined.ResultsNestin and VEGF expression in tumour cells were more frequent in supratentorial tumours [89% (33/37) and 65% (24/37) respectively], and were associated with a significantly poor progression‐free survival (PFS). VEGF expression did not reveal any correlation with necrosis or bizarre vascular patterns.ConclusionsSupratentorial location is an independent predictor of a poor PFS. Significant coexpression of nestin and VEGF suggests that latter possibly augments stem cell survival. Thus, anti‐VEGF therapy may be a good option in future for nestin immunopositive ependymomas.
Reexpansion pulmonary edema: review of pediatric cases
Authors: Kira Shinichiro 
Published: November 2013

SummaryReexpansion pulmonary edema (RPE) is an increased permeability pulmonary edema that usually occurs in the reexpanded lung after several days of lung collapse. This condition is recognized to occur more frequently in patients under the age of 40 years, but there has been no detailed analysis of reported pediatric cases of RPE to date. For this review, PubMed literature searches were performed using the following terms: ‘re(‐)expansion pulmonary (o)edema’ AND (‘child’ OR ‘children’ OR ‘infant’ OR ‘boy’ OR ‘girl’ OR ‘adolescent’). The 22 pediatric cases of RPE identified were included in this review. RPE was reported in almost the entire pediatric age range, and as in adult cases, the severity ranged from subclinical to lethal. No specific treatment for RPE was identified, and treatment was administered according to the clinical features of each patient. Of the 22 reported cases, 10 occurred during the perioperative period, but were not related to any specific surgical procedures or anesthetic techniques, or to the duration of lung collapse. Pediatric anesthesiologists should be aware that pediatric RPE can occur after reexpansion of any collapsed lung and that some invasive therapies can be useful in severe cases.
Retrospective Analysis of the Relationship Between Infantile Seborrheic Dermatitis and Atopic Dermatitis
Authors: Alexopoulos Alex , Kakourou Talia , Orfanou Irene , Xaidara Athina , Chrousos George 
Published: November 2013

AbstractA growing number of dermatologists dispute the existence of infantile seborrheic dermatitis (ISD) as an independent clinical entity. Therefore the aim of the present study was to estimate the epidemiologic features of ISD in a defined population of Greek children, assess its course, and identify associations, if any, with other common dermatoses of childhood. Children from the region of Athens who were examined and diagnosed with typical clinical features of ISD between 1997 and 2011 were included in the study. The relevant data were collected retrospectively from their medical records using a standardized form. Eighty‐seven children were enrolled (50 boys, 37 girls; mean age 3.1 mos at the time of ISD diagnosis). The main body areas affected were the scalp and face for the majority of the children (78/87), whereas the trunk and limbs were less frequently involved (9/87). In all cases, erythema and scaling of affected patients were mild to moderate. Forty‐nine of the 87 children were followed up over a period of 5 years. Thirty children in this group developed features of atopic dermatitis (AD) at a later stage, according to the UK diagnostic criteria of AD, and 23 of these children were diagnosed with AD, at an average time interval of 6.4 months from ISD onset, and seven presented with clinical features of AD at the time of ISD diagnosis. The remaining 19 children in the follow‐up group progressed without developing any other chronic skin disease, and all recovered within 6 months of its onset. Thirty‐eight had no further follow‐up after their initial ISD diagnosis. In spite of the lack of information on the disease course for the last group, assuming they all recovered, the prevalence of AD (34.4%) in our ISD sample was significantly higher than the prevalence of AD (10.7%) in the general population for the same age group, as shown in a previous study performed in the municipality of Athens (p < 0.001). A significant number of children were found to develop AD shortly after their ISD diagnosis. This finding demonstrates a strong association in the clinical course between the two diseases or indicates that the two diseases may be in the same clinical spectrum. Further epidemiologic studies must be conducted to assess the significance of this finding.
Evaluation of Wound Care Options in Patients with Recessive Dystrophic Epidermolysis Bullosa: A Costly Necessity
Authors: Kirkorian Anna Yasmine , Weitz Nicole A. , Tlougan Brook , Morel Kimberly D. 
Published: November 2013

AbstractRecessive dystrophic epidermolysis bullosa (RDEB) is a genetic disorder in which mutations in collagen VII, the main component of the anchoring fibril, lead to skin fragility and to the development of acute and chronic wounds. Wound care and dressing changes are an important part of the daily lives of individuals with RDEB. Ideal wound care should improve wound healing, minimize pain, and improve quality of life. The objective of the current study was to review wound care options that might be used in a patient with RDEB and calculate the cost of these various options based on publicly available pricing of wound care products. There is a wide range of costs for wound care options in patients with RDEB. For example, a 1‐day supply of dressing for a neonate boy with RDEB ranges from $10.64 for the least expensive option to $127.54 for the most expensive option. Wound care in patients with severe, generalized RDEB has not only a significant economic effect, but also directly affects quality of life in this patient population. Although randomized controlled trials evaluating different wound care products in patients with RDEB are lacking, small studies and expert opinion support the use of specialized nonadherent dressings that minimize skin trauma and promote wound healing. Until there is a cure, prospective studies are needed to assess pain, quality of life, and wound healing associated with the use of specialized wound care products for this life‐altering condition.
Vibrational communication and mating behaviour of Dichelops melacanthus (Hemiptera: Pentatomidae) recorded from loudspeaker membranes and plants
Authors: BLASSIOLI‐MORAES MARIA C. , MAGALHÃES DIEGO M. , ČOKL ANDREJ , LAUMANN RAÚL A. , DA SILVA JOSEANE P. , SILVA CLEONOR C. A. , BORGES MIGUEL 
Published: November 2013

AbstractVibrational communication is important for successful mating in various stink bugs species. The vibrational signals from males and females of Dichelops melacanthus Dallas (Hemiptera: Pentatomidae) are recorded from a nonresonant substrate (i.e. a loudspeaker membrane) to characterize the temporal and spectral properties of these vibrational signals, as well as on a resonant substrate (i.e. bean plants) to obtain information about how these signals are altered when they are transmitted through the plants. On the loudspeaker membrane, D. melacanthus males and females emit only one male or one female song, respectively. However, when the insects are placed on bean leaves, a more complex repertoire is recorded, with three different songs for each sex. The first female and male songs appear to have calling functions and the third male and female songs are emitted during courtship. The second female and male songs are emitted after the first song, although their functions in mating behaviour are not clear. The identified repertoire is similar to those of other Neotropical stink bugs, starting with songs 1 and 2 and developing into song 3. Frequency modulation is observed in the female songs recorded from the loudspeaker membrane and the plants. The signals recorded from plants present higher harmonic peaks compared with the signals recorded from the loudspeaker membrane. The presence of species and sex‐specific songs during mating confirms the important role of vibrational communication in mate location and recognition. The temporal and spectral characteristic signals are influenced by the substrate used to record the songs emitted by D. melacanthus.
‘To serve us in that behalf when our pleasure is to call for them’: performing boys in Renaissance England
Authors: Mamujee Shehzana 
Published: November 2013

This essay argues for the recognition of a culture of child performance that flourished throughout Renaissance England, and foregrounds the social contexts from which the quasi‐professional boy player emerged at the end of the sixteenth century. Examining the academic and religious provenance of child acting in the period and the ubiquity of boys as performers in numerous semi‐dramatic royal and civic pageants, this article reveals that the boy's role in Renaissance theatre begins with the non‐professional performative culture to which he is integral, and stretches far beyond his presence as the transvestite boy‐heroine on an all‐male stage.The examination of the boy's theatrical roles is further contextualized in relation to moralistic, prescriptive literature on the family, which conceptualizes the child as the property of his parents. The discussion emphasizes the cultural perceptions of subordination, economic import and ownership tied in with child development, in order to make visible the link between the child's role in the theatre and his status in the family. The Renaissance boy actor served as a commodified entity which typified a social and economic structure in which children in general played a vital part.
Quantifying the impact of former glaciation on catchment‐wide denudation rates derived from cosmogenic 10Be
Authors: Glotzbach Christoph , Röttjer Markus , Hampel Andrea , Hetzel Ralf , Kubik Peter W. 
Published: November 2013

AbstractGlacial denudation can significantly perturb terrestrial cosmogenic nuclide depth profiles and, if this is not corrected for, derived apparent denudation rates will overestimate the actual denudation rates. Here we determine how much 10Be‐derived denudation rates – calculated under the assumption of steady state – deviate from actual denudation rates as a function of three parameters: (1) the total amount of glacial denudation, (2) the post‐glacial denudation rate and (3) the time elapsed since deglaciation. We provide correction lines for the full parameter space explored (glacial denudation: 0.01–100 m; post‐glacial denudation rate: 1–1000 mm/ka; deglaciation: 1–100 ka before present), to evaluate and, if necessary, correct denudation rates for the impact of glacial denudation. Applied to 10Be‐derived catchment‐averaged denudation rates for formerly glaciated catchments in the Black Forest, Germany, we find that uncorrected denudation rates overestimate actual rates by up to a factor of three.
Design and Test Results of a Ultra High Loaded Single Stage High Pressure Turbine
Authors: Hura Harjit S. , Carson Scott , Saeidi Rob , Shin Hyoun-Woo , Giel Paul 
Published: November 2013

This paper describes the engine and rig design, and test results of an ultra-highly loaded single stage high pressure turbine. In service aviation single stage HPTs typically operate at a total-to-total pressure ratio of less than 4.0. At higher pressure ratios or energy extraction the nozzle and blade both have regions of supersonic flow and shock structures which, if not mitigated, can result in a large loss in efficiency both in the turbine itself and due to interaction with the downstream component which may be a turbine center frame or a low pressure turbine. Extending the viability of the single stage HPT to higher pressure ratios is attractive as it enables a compact engine with less weight, and lower initial and maintenance costs as compared to a two stage HPT.
The present work was performed as part of the NASA UEET (Ultra-Efficient Engine Technology) program from 2002 through 2005. The goal of the program was to design and rig test a cooled single stage HPT with a pressure ratio of 5.5 with an efficiency at least two points higher than the state of the art. Preliminary design tools and a design of experiments approach were used to design the flow path. Stage loading and through-flow were set at appropriate levels based on prior experience on high pressure ratio single stage turbines. Appropriate choices of blade aspect ratio, count, and reaction were made based on comparison with similar HPT designs. A low shock blading design approach was used to minimize the shock strength in the blade during design iterations. CFD calculations were made to assess performance.
The HPT aerodynamics and cooling design was replicated and tested in a high speed rig at design point and off-design conditions. The turbine met or exceeded the expected performance level based on both steady state and radial/circumferential traverse data. High frequency dynamic total pressure measurements were made to understand the presence of unsteadiness that persists in the exhaust of a transonic turbine.
Flame Density Ratio Effects on Vortex Dynamics of Harmonically Excited Bluff Body Stabilized Flames
Authors: Emerson Benjamin , Murphy Kelvin , Lieuwen Tim 
Published: November 2013

This paper presents an experimental study of acoustically forced bluff body stabilized flames, motivated by the problem of combustion instabilities. The goal of the work is to better understand the flame and flow behavior as functions of the proximity of the acoustic frequency to natural hydrodynamic instability frequencies. It is well known that iso-density, high Re bluff body wakes are globally unstable, exhibiting the Von Karman vortex street. In reacting flows, however, this global mode is suppressed if the density ratio across the flame is sufficiently high. Thus, the density ratio is an important parameter that influences the global mode growthrate. In this study, the flame was longitudinally forced over a range of hydrodynamic global mode to forcing frequency ratios, density ratios, and forcing amplitudes. Longitudinal forcing leads to the symmetric rollup of the two separating shear layers. When the forcing frequency is in the vicinity of the wake’s global mode frequency, the global mode locks into the forcing frequency, and the symmetric shear layers quickly stagger as they convect downstream, leading to a large scale, sinuous flapping of the wake and flame. The axial position at which staggering occurs is a function of the forcing amplitude and the proximity of the forcing frequency to the global mode frequency.
The lock-in phenomenon amplifies the flame’s motion at the forcing frequency. However, if the vortices stagger to a fully sinuous structure, this causes a significant reduction in the flame’s oscillatory heat release through phase cancellation of the upper and lower flame branches. Therefore, if a low density ratio flame is subjected to longitudinal acoustic forcing near its global mode frequency, it will respond with weaker heat release fluctuations than it would away from lock-in. This is true even though the local degree of flame flapping is quite significant. Thus, the results of this study show some phenomena that contradict conventional notions, namely that forcing a globally unstable flow near its global mode frequencies can lead to diminished local heat release oscillations.
Cooling Efficiency for Assessing the Cooling Performance of an Effusion Cooled Combustor Liner
Authors: Wurm B. , Schulz A. , Bauer H.-J. , Gerendas M. 
Published: November 2013

Based on experimental results on a liner of a modern direct lean injection combustion chamber using coolant ejection from both effusion cooling holes and a starter film, a method is presented that allows the assessment of the cooling performance of the liner.
As the main focus of the present study is a deeper understanding of the interaction of swirl flow and near wall cooling flow, wall pressure measurements are performed for the calculation of local blowing ratios and local coolant mass fluxes. Thermal investigations allow the calculation of adiabatic film cooling effectiveness and heat transfer coefficients. The pressure drop across the effusion cooled liner is varied between 1% and 3% of the total pressure of the main flow. As experiments are performed without combustion and at low temperature, the influence of radiation is neglected. Results show the impact of the swirled main flow on the stability of the starter film and on the effusion cooling performance. Stagnation areas which could be identified by wall pressure measurements are confirmed by detailed PIV measurements. Thermal investigations reveal reduced cooling performance in the respective stagnation areas. For the definition of the non dimensional cooling efficiency the measurement area is sub divided into rhombic sections, which are located around each effusion cooling hole. Based on the measurement results presented, heat fluxes per unit area can then be calculated and put together to the cooling efficiency.
Effects of Tip Clearance Gap and Exit Mach Number on Turbine Blade Tip and Near-Tip Heat Transfer
Authors: Anto K. , Xue S. , Ng W. F. , Zhang L. J. , Moon H. K. 
Published: November 2013

This study focuses on local heat transfer characteristics on the tip and near-tip regions of a turbine blade with a flat tip, tested under transonic conditions in a stationary, 2-D linear cascade with high freestream turbulence. The experiments were conducted at the Virginia Tech transonic blow-down wind tunnel facility. The effects of tip clearance and exit Mach number on heat transfer distribution were investigated on the tip surface using a transient infrared thermography technique. In addition, thin film gages were used to study similar effects in heat transfer on the near-tip regions at 94% height based on engine blade span of the pressure and suction sides. Surface oil flow visualizations on the blade tip region were carried-out to shed some light on the leakage flow structure. Experiments were performed at three exit Mach numbers of 0.7, 0.85, and 1.05 for two different tip clearances of 0.9% and 1.8% based on turbine blade span. The exit Mach numbers tested correspond to exit Reynolds numbers of 7.6 × 105, 9.0 × 105, and 1.1 × 106 based on blade true chord. The tests were performed with a high freestream turbulence intensity of 12% at the cascade inlet.
Results at 0.85 exit Mach showed that an increase in the tip gap clearance from 0.9% to 1.8% translates into a 3% increase in the average heat transfer coefficients on the blade tip surface. At 0.9% tip clearance, an increase in exit Mach number from 0.85 to 1.05 led to a 39% increase in average heat transfer on the tip. High heat transfer was observed on the blade tip surface near the leading edge, and an increase in the tip clearance gap and exit Mach number augmented this near-leading edge tip heat transfer. At 94% of engine blade height on the suction side near the tip, a peak in heat transfer was observed in all test cases at s/C = 0.66, due to the onset of a downstream leakage vortex, originating from the pressure side. An increase in both the tip gap and exit Mach number resulted in an increase, followed by a decrease in the near-tip suction side heat transfer. On the near-tip pressure side, a slight increase in heat transfer was observed with increased tip gap and exit Mach number. In general, the suction side heat transfer is greater than the pressure side heat transfer, as a result of the suction side leakage vortices.
An Investigation Into Performance Modeling of a Small Gas Turbine Engine
Authors: Leylek Zafer , Anderson Wesly S. , Rowlinson Glen , Smith Nigel 
Published: November 2013

A small gas turbine performance modeling and testing project has been completed as part of a DSTO research program. The main objective of the program was to enhance capability in understanding and modeling the thermodynamic and performance characteristics of gas turbine engines. The secondary objective of the program was development of a simple, low-cost test apparatus for basic thrust augmentation technologies and infrared suppression studies.
Engine performance modeling was conducted using commercial software (Gasturb) and an in-house developed code. Various techniques were used in predicting component performance which included scaling of published performance data, use of standard empirical performance models, mean-line and through flow codes and detailed Computational Fluid Dynamics (CFD) analysis. A comparison of the advantages and disadvantages of each method was made and compared with engine test data.
The AMT Olympus HP turbojet engine was used as the test engine. The engine was instrumented using a bell mouth to measure mass flow rate, load cell to measure thrust, tachometer to measure engine rotational speed, thermocouples to measure flow total temperature and pressure transducers to measure wall static pressure at various stations along the engine.
A pair of Olympus engines were tested for comparison during baseline testing, with consistent results between the two. The first engine was fully instrumented and used in all of the tests. This engine was used to test the engine standard operating line tests to determine bulk performance and establish compressor operating line. Tests were repeated and error analysis conducted to ensure repeatability and validity of the data. The second engine was used as a control engine with only the OEM supplied instrumentation, thrust and bell mouth used for benchmarking purposes. The data from both engines have been compared with the engine performance model and OEM data.
A number of other tests were completed to “stress” the engine and shift its operating line closer to the compressor stall line. This was accomplished through various types of exhaust blockage. Stall behaviour was clearly evident in the initial commissioning tests where a large nozzle blockage resulted in engine stall and incomplete start-up. Engine performance and compressor map results from the tests have been compared to the engine performance model with good agreement.