bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insects running on elastic surfaces
Authors: Spence Andrew J. , Revzen Shai , Seipel Justin , Mullens Chris , Full Robert J. 
Published: May 2010

SUMMARY
In nature, cockroaches run rapidly over complex terrain such as leaf litter. These substrates are rarely rigid, and are frequently very compliant. Whether and how compliant surfaces change the dynamics of rapid insect locomotion has not been investigated to date largely due to experimental limitations. We tested the hypothesis that a running insect can maintain average forward speed over an extremely soft elastic surface (10 N m−1) equal to 2/3 of its virtual leg stiffness (15 N m−1). Cockroaches Blaberus discoidalis were able to maintain forward speed (mean ± s.e.m., 37.2±0.6 cm s−1 rigid surface versus 38.0±0.7 cm s−1 elastic surface; repeated-measures ANOVA, P=0.45). Step frequency was unchanged (24.5±0.6 steps s−1 rigid surface versus 24.7±0.4 steps s−1 elastic surface; P=0.54). To uncover the mechanism, we measured the animal's centre of mass (COM) dynamics using a novel accelerometer backpack, attached very near the COM. Vertical acceleration of the COM on the elastic surface had a smaller peak-to-peak amplitude (11.50±0.33 m s−2, rigid versus 7.7±0.14 m s−2, elastic; P=0.04). The observed change in COM acceleration over an elastic surface required no change in effective stiffness when duty factor and ground stiffness were taken into account. Lowering of the COM towards the elastic surface caused the swing legs to land earlier, increasing the period of double support. A feedforward control model was consistent with the experimental results and provided one plausible, simple explanation of the mechanism.
Experimental study of multiple-channel automotive underbody diffusers
Authors: Jowsey L , Passmore M 
Published: May 2010

Underbody diffusers are used widely in race car applications because they can significantly improve the cornering capacity of the vehicle through the generation of a downforce. They are also likely to have a wider role in reducing the drag in road vehicles as it becomes increasingly important to reduce emissions of carbon dioxide. This paper reports on a wind tunnel investigation, using a simplified bluff body model, into the effect of splitting a simple plane diffuser into multiple channels. Tests are reported for a range of diffuser geometries suitable for road and race car applications. The results for the lift, the drag, and the incremental changes to the lift-to-drag ratio are reported and discussed in terms of the underbody pressures. While broadly similar trends to the single-channel plane diffuser are seen in the multiple-channel diffuser configurations, it was found that the effect of increasing the number of channels depended on the flow regimes present in the plane diffuser. At angles just above the plane diffuser optimum, where the flow is partially separated, the multiple-channel configurations give large improvements in the downforce with minimal increase in the drag, significantly extending the performance envelope. The pressure maps indicate that the gains occur through improved diffuser pumping and pressure recovery in both the inner and the outer channels.
Improvements in the performance and pollutant emissions for stoichiometric diesel combustion engines using a two-spray-angle nozzle
Authors: Kim J-H , Reitz R D , Park S W 
Published: May 2010

An experimental and numerical study was conducted to investigate the effect of the nozzle layout on the combustion and emission characteristics for stoichiometric diesel combustion. In order to improve fuel—air mixing, a new concept of nozzle layout was studied. The nozzle has two spray angles, one heading for the bowl and the other targeting the squish area (two-spray-angle nozzle (2SAN)). The spray included angles of the nozzle layout are 150° (upper holes) and 70° (lower holes), and the start-of-injection timings were swept from −33° to −9° after top dead centre. The results of the 2SAN were compared with those of a well-characterized baseline single-hole nozzle (SHN) with a 130° spray included angle. The experimental results showed that the engine performance and carbon monoxide emissions were reduced significantly by using the 2SAN instead of the SHN with stoichiometric diesel combustion. However, hydrocarbon emissions were increased owing to fuel-film formation. In addition, the range of optimal injection timings for reduced fuel consumption for the 2SAN is wider than that of the SHN because the upper spray of the 2SAN utilizes oxygen in the squish area more efficiently.
Development of a three-dimensional collision risk model tool to assess safety in high density en-route airspaces
Authors: Sáez Nieto F J , Arnaldo Valdés R , García González E J , McAuley G , Izquierdo M I 
Published: May 2010

A three-dimensional collision risk model (CRM) is being developed by the Technical University of Madrid and INECO for the European Organization for the Safety of Air Navigation (EUROCONTROL) as a method of assessing the European en-route risk, due to all causes and across all dimensions within the airspace. This model provides a method for assessing the level of safety in en-route airspaces, where controllers monitor air traffic by means of radar and provide tactical instructions to aircraft, and also provides safety metrics required to understand these results. The three-dimensional CRM is based on the analysis of recorded aircraft tracks from radar data processing systems in order to identify and analyse automatically all proximate events within a time span and a given volume of airspace. The three-dimensional collision risk analytical model is backed up by a modular software tool developed to analyse radar data samples and to support the different processes that need to be addressed to obtain the required three-dimensional CRM outcome. The main purpose of this research is to show how the three-dimensional CRM software prototype performs an in-depth analysis of radar data, in order to provide robust information on air traffic factors and safety metrics.
Passive magnetic attitude stabilization system of the EduSAT microsatellite
Authors: Battagliere M L , Santoni F , Piergentili F , Ovchinnikov M , Graziani F 
Published: May 2010

Passive magnetic attitude stabilization systems are simple, easy to realize, cheap, and do not require software development and on-board energy consumption. Owing to these features, passive magnetic attitude stabilization systems were selected for the EduSAT (Educational Satellite) microsatellite, a student-built satellite funded by the Italian Space Agency, scheduled to be launched in the last quarter year of 2010. The passive magnetic attitude stabilization system is based on a permanent magnet, which provides a restoring torque to align an oriented axis of the satellite with the Earth's magnetic field direction, and an energy dissipation system, which can consist of a set of permeable rods magnetized by the oscillation of the geomagnetic field along their axis. UNISAT-3 attitude determination results after 1 year from its launch demonstrated the necessity of an accurate design and manufacturing process of soft magnetic strips. Predicting system performance in orbit and evaluating the obtainable accuracy are not trivial: the main problem is knowing the effective magnetization of the permeable rods. The paper deals with sizing, choice of material, manufacturing process, and arrangement of a set of permeable rods on board the EduSAT microsatellite on the basis of previous flight experience.
Nuclear Power Sources: A Key Enabling Technology for Planetary Exploration
Authors: Summerer L , Stephenson K 
Published: May 2010

Nuclear power sources for space (NPS) are, according to current physics knowledge, the only power source option for some classes of space missions. Europe has successfully used NPS exploration missions (e.g. Huygens lander on Titan and Ulysses spacecraft). Although some small-scale study and development efforts have been undertaken at the national level during the past 40 years, these did not go beyond study and early prototyping level. The present paper introduces the European situation with respect to the development and use of NPS.
Lubricant ageing effects on the friction characteristics of wet clutches
Authors: Berglund K , Marklund P , Larsson R 
Published: May 2010

The friction characteristics and performance of wet clutches have been investigated by several authors. Studies have also been made to understand the frictional performance during the service life of the clutch system. However, most lifetime studies have been conducted for systems with paper-based friction material so that systems using sintered bronze friction material remain largely unexplored. To study the friction performance of how these systems can vary over time, the friction characteristics for a clutch system using lubricants aged in three different ways were compared. The effects on friction characteristics resulting from oxidation of the lubricant, reduced additive concentration, and ageing under real operating conditions in a wet clutch test rig were studied. The oxidation effects on friction characteristics were examined using a modified waterless turbine oil oxidation stability test on a fully formulated lubricant. Five oxidation time periods from 48 to 408 h were investigated. For each period of oxidation, a friction performance test was run using a pin-on-disc machine. The ageing carried out in a wet clutch test rig is a standard test of a wet clutch systems manufacturer which is used in order to verify that an oil-friction disc combination will last the full service life of the specific application. This test gives a realistic ageing process similar to that in a wet clutch in a field test. Under boundary-lubricated conditions, additives are vital to the performance of wet clutches. Therefore, the effect of reducing the additive concentration in the oil was also studied, in the range of 10 to 100 per cent of the original additive package used in the fully formulated wet clutch lubricant. Results showed that a general friction increase can be observed for oxidation, additive reduction, and test rig ageing. It was also concluded that different methods of simulating the wet clutch ageing process differ and cannot be directly correlated with each other.
Hydrodynamic force and moment in pure rolling lubricated contacts. Part 1: Line contacts
Authors: Biboulet N , Houpert L 
Published: May 2010

Hydrodynamic rolling force and moments in line contact have been studied in detail using isoviscousrigid (IVR) and elastohydrodynamic (EHL) models. Using fully flooded assumptions, curve-fitted relationships are suggested for calculating the IVR and EHL hydrodynamic rolling force per unit length. At high speed and light load, EHL numerical results converge towards IVR results so that a single curve-fitted relationship has been derived for covering the full range of operating conditions with a rapid transition from IVR to EHL regime of lubrication. Results obtained are often close to published results (especially in the IVR regime). The EHL hydrodynamic rolling force per unit length is found to be load independent, while load exponents ranging from 0.01 to 0.37 can be found in the literature. A single relationship for both lubrication regimes (IVR and EHL) is given for deriving a starvation factor function of the ratio between the film thickness at the inlet meniscus and the fully flooded minimum film thickness. Finally, the calculation of the total power loss per unit length has also been conducted by integrating through the film and along the rolling direction the power loss per unit volume (defined as the product shear stress time shear rate). Results obtained are consistent with the calculation of the rolling force per unit length.
Hydrodynamic force and moment in pure rolling lubricated contacts. Part 2: Point contacts
Authors: Biboulet N , Houpert L 
Published: May 2010

Hydrodynamic rolling force and moments in point contact have been studied in detail using isoviscousrigid (IVR) and elastohydrodynamic (EHL) models. Using fully flooded assumptions, curve-fitted relationships are given for calculating the IVR and EHL hydrodynamic rolling forces. Both are proportional (or almost proportional in the IVR case) to 2 a, the Hertzian contact length being perpendicular to the rolling direction, and are also functions of the dimensionless speed parameter. A single curve-fitted relationship has been derived to cover the full range of operating conditions with a smooth transition from IVR to EHL regime of lubrication. The results obtained are slightly higher than those previously published (the ratio being of the order of 1.5 for usual operating conditions). Point contact and line contact (with a contact length £ being equal to the point contact length 2 a) hydrodynamic rolling forces have also been compared. The point contact forces are about 26 per cent larger than those obtained using line contact relationship (published in part 1) because of a larger domain of integration in the lateral direction. By limiting the width of the integration domain to £ (roller length or ball diameter), the effect of 2 a/£ on the hydrodynamic rolling force has been studied, leading to the derivation of a truncation factor C. As the load increases, 2 a increases and the truncation factor decreases until reaching a limit when ellipse truncation starts because 2 a/£ is equal to or larger than one. Using the truncation factor and limiting the 2 a/£ ratio to one, it was found that point contact and line contact hydrodynamic forces are the same within a few per cent. A single point contact relationship can therefore be suggested, covering the IVR to EHL operating conditions with a smooth transition between these lubrication regimes, and also a smooth transition from point contact to line contact as the load increases and contact ellipse truncation occurs. Finally, calculations of power losses due to the Poiseuille flow in the rolling direction x and in the perpendicular direction z show that the power loss in the z direction is usually very small for wide elliptical contacts and that most of the power is dissipated in the inlet and outlet, with a 26 per cent contribution of the integration domain defined out the range − a < z < a. This result is in line with the truncation factor defined previously.
‘You need that loving tender care’: maternity care experiences and expectations of ethnic minority women born in the United Kingdom
Authors: Puthussery Shuby , Twamley Katherine , Macfarlane Alison , Harding Seeromanie , Baron Maurina 
Published: May 2010

Objective: To explore the maternity care experiences and expectations of United Kingdom (UK)-born ethnic minority women. Methods: Qualitative in-depth interviews with 34 UK-born mothers of Black Caribbean, Black African, Indian, Pakistani, Bangladeshi and Irish descent, recruited mainly from nine National Health Service (NHS) maternity units in England. Results: Overall, women felt that their ethnic background did not matter at all with respect to the care they received. UK-born women's familiarity with the system and the absence of language barriers were felt to be influential in getting treated the same as White women. Women stressed the need for professionals to be ‘sensitive’ and ‘delicate’ in their interactions and wanted ‘continuity of care’. In general, they were positive about the adequacy of the information given during their antenatal appointments, but some women found it difficult to get access to antenatal classes. Women valued good communication and consistent information, with their views acknowledged and their questions answered consistently. They also expressed the need for better physical environments in maternity units. Conclusions: Our findings contribute to the growing evidence about the need to improve maternity and postnatal care, and to develop more sensitive and women-centred care for all women irrespective of ethnic background.
Is there an association between the quality of hospitals’ research and their quality of care?
Authors: Pons Joan , Sais Carolina , Illa Carles , Méndez Raül , Suñen Eduard , Casas Mercé , Camí Jordi 
Published: May 2010

Objective: It is often claimed that hospitals that are leaders in biomedical research provide higher health care quality, or vice versa. Although several studies have shown a relationship between teaching status and quality of care, none has analysed the association between research output and hospital outcomes. Our aim was to determine whether there is a relationship between bibliometric measures of research output in acute hospitals and hospital mortality for two common cardiac conditions. Methods: A cross-sectional analysis of secondary data of in-hospital risk-adjusted mortality for congestive heart failure and acute myocardial infarction (2002-2004) and several bibliometric measures of publications (1996- 2004) in cardiovascular disease. The setting was 50 acute Spanish public hospitals, voluntarily participating in an external quality initiative, with more than 30 medical cases of congestive heart failure and acute myocardial infarction per year, and more than five citable papers in the field of heart disease. Spearman's rho non-parametric correlation coefficient was used to assess association. Results: There was a low-to-moderate negative correlation between the risk-adjusted mortality ratio and the weighted citations ratio: 20.43 (95% CI 20.17 to 20.63) for congestive heart failure and 20.37 (20.10 to 20.59) for acute myocardial infarction. Teaching status and the technological level of the hospital had a stronger correlation with hospital mortality. Conclusions: Measures of research output could be considered for incorporation into comparisons of the quality of hospitals. A weighted citations ratio is the most suitable measure of research output, but more research is needed on the interplay between research and practice as complementary ways of developing medical knowledge.
Prenatal diagnosis of 4p deletion with aortic valve stenosis
Authors: Witters Ingrid , Gyselaers Wilfried , Van Holsbeke Caroline , Mesens Tinne , Theyskens Claire , Duvivier Patricia , Fryns Jean-Pierre 
Published: May 2010

Wolf-Hirschhorn syndrome (WHS) is caused by variable sized terminal deletions of the short arm of chromosome 4 (chromosomal region 4p16.3) and usually presents as severe intrauterine growth retardation with characteristic dysmorphic features (hypertelorism, a short philtrum with downturned corners of the mouth and a ‘Greek warrior helmet appearance’ of the face), developmental delay and epilepsy. Often WHS is only diagnosed postnatally but prenatal diagnosis has been reported in the presence of intrauterine growth retardation with facial dysmorphism, cardiac malformations (ventricular septal defect, arrhythmia) or other associated malformations (oesophageal atresia, renal hypoplasia, diaphragmatic hernia, foot deformity, choroid plexus cysts, corpus callosumagenesis, hypospadias), or in the present of a parental balanced translocation. Here we present the prenatal diagnosis of WHS based on the prenatal onset of growth delay and characteristic facial features and aortic valve stenosis.
CD163 Expression Is Present in Cutaneous Histiocytomas but Not in Atypical Fibroxanthomas
Authors: Sachdev Reena , Robbins Jason , Kohler Sabine , Vanchinathan Vijay , Schwartz Erich J. , Sundram Uma N. 
Published: May 2010

Abstract
CD163, a hemoglobin scavenger receptor, is expressed in monocytes and macrophages. Recent work has shown that this marker is specific for neoplasms of histiocytic differentiation. Our aim was to test the ability of CD163 to separate cutaneous histiocytomas from their morphologic mimics. We tested the expression of CD163 in 78 cases, including 19 xanthogranulomas, 16 atypical fibroxanthomas, 6 reticulohistiocytomas, 8 epithelioid cell histiocytomas, 9 cases of Langerhans cell histiocytosis, 10 xanthomas, and 10 intradermal Spitz nevi. CD163 expression was seen in all xanthogranulomas and reticulohistiocytomas, 4 epithelioid cell histiocytomas, 2 cases of Langerhans cell histiocytosis, and 8 xanthomas but was absent in atypical fibroxanthomas and Spitz nevi. CD163 is an excellent marker for confirming histiocytic differentiation and is useful in eliminating morphologic mimics such as Spitz nevi from the differential diagnosis. The lack of CD163 in atypical fibroxanthomas argues against a histiocytic origin for this tumor.
Naproxen Metabolites Interfere With Certain Bilirubin Assays
Authors: Dasgupta Amitava , Langman Loralie J. , Johnson Myrtle , Chow Loretta 
Published: May 2010

Abstract
A recent report indicated significant interference of naproxen with total bilirubin measurement when using the Jendrassik and Grof method. We explored the possibility of avoiding this interference by using a different method. We observed that naproxen has no effect on total bilirubin measurement by any method, but O-desmethylnaproxen (the naproxen metabolite) interfered significantly with total bilirubin assays using the Jendrassik and Grof method (Beckman Coulter [Brea, CA] and Siemens [Tarrytown, NY] bilirubin method). The Roche (Indianapolis, IN) bilirubin assay based on a different method was not affected. When serum samples of 9 patients receiving naproxen were analyzed for total bilirubin level, we observed good correlation in total bilirubin values measured by all 3 methods in 7 of 9 patients with therapeutic naproxen concentrations. In contrast, in 2 patients with elevated naproxen levels, the total bilirubin values observed by using the Beckman and Siemens methods were significantly higher than the value obtained by the Roche assay. The naproxen metabolite interferes with assays based on the Jendrassik and Grof method but not with the Roche bilirubin assay.
Biological and Analytical Variability of a Novel High-Sensitivity Cardiac Troponin T Assay
Authors: Vasile Vlad C , Saenger Amy K , Kroning Jean M , Jaffe Allan S 
Published: May 2010

AbstractBackground: High-sensitivity cardiac troponin assays will augment the frequency of increased results, making important the determination of reference change values to distinguish acute from chronic increases. We assessed short- and long-term biological variability of cardiac troponin T (cTnT) in healthy subjects with a novel high-sensitivity (hs) assay.Methods: We collected blood from 20 healthy volunteers at 5 time points for short-term study and biweekly at 4 times from the same volunteers for long-term study. We analyzed serum samples in duplicate with a hscTnT assay on the Roche Modular E170 and computed reference change values (RCVs) for analytical, intraindividual, interindividual, and total change values (CVA, CVI, CVG, and CVT, respectively) and the index of individuality (II). We calculated RCVs by using a log-normal approach, owing to the skewed results of the data.Results: Short- and long-term CVA values were 53.5% and 98%. CVI and CVG were 48.2% and 85.9%, respectively, for short-term studies and 94% and 94% for long-term studies. Mean δ values for the within-day study were 58% and −57.5%, and between-day mean δ values were 103.4% and −87%. Within- and between-day IIs were 0.8 and 0.14, respectively.Conclusions: The biological variation demonstrated with the hscTnT assay is higher than prior data for cardiac troponin I. This may be attributed to differences in biology or assay imprecision at low concentrations. A short-term change (RCV log normal) of 85% and a long-term change of 315% is necessary to define a changing pattern.