bluuebunny/crossref_metadata_2025 huggingface dataset:
IL-21 induces death of marginal zone B cells during chronic inflammation
Authors: Tortola Luigi , Yadava Koshika , Bachmann Martin F. , Müller Christoph , Kisielow Jan , Kopf Manfred
Published: September 2010

Interleukin-2 (IL-2) and IL-21 share activities in the control of T- and B-cell maturation, proliferation, function, and survival. However, opposing roles for IL-2 and IL-21 have been reported in the development of regulatory T cells. To dissect unique, redundant, and opposing activities of IL-2 and IL-21, we compared T- and B-cell development and function in mice lacking both IL-2 receptor α (IL-2Rα) and IL-21R (double knockouts [DKO]) with single knockout and wild-type (WT) mice. Similarly to il2ra−/− mice, DKO showed reduced numbers of regulatory T cells and, consequently, hyper-activation and proliferation of T cells associated with inflammatory disease (ie, colitis), weight loss, and reduced survival. The absence of IL-2Rα resulted in overproduction of IL-21 by IFN-γ–producing CD4+ T cells, which induced apoptosis of marginal zone (MZ) B cells. Hence, MZ B cells and MZ B-cell immunoglobulin M antibody responses to Streptococcus pneumoniae phosophorylcholine were absent in il2ra−/− mice but were completely restored in DKO mice. Our results highlight key roles of IL-2 in inhibiting IL-21 production by CD4+ T cells and of IL-21 in negatively regulating MZ B-cell survival and antibody production.
African-American inflammatory bowel disease in a Southern U.S. health center
Authors: Veluswamy Hemanth , Suryawala Kunal , Sheth Ankur , Wells Shannon , Salvatierra Erik , Cromer Walter , Chaitanya Ganta V , Painter Annette , Patel Mihir , Manas Kenneth , Zwank Ellenmarie , Boktor Moheb , Baig Kondal , Datti Balaji , Mathis Michael J , Minagar Alireza , Jordan Paul A , Alexander Jonathan S
Published: September 2010

Background

Inflammatory Bowel Diseases (IBD) remain significant health problems in the US and worldwide. IBD is most often associated with eastern European ancestry, and is less frequently reported in other populations of African origin e.g. African Americans ('AAs'). Whether AAs represent an important population with IBD in the US remains unclear since few studies have investigated IBD in communities with a majority representation of AA patients. The Louisiana State University Health Sciences Center in Shreveport (LSUHSC-S) is a tertiary care medical center, with a patient base composed of 58% AA and 39% Caucasian (W), ideal for evaluating racial (AA vs. W) as well and gender (M vs. F) influences on IBD.

Methods

In this retrospective study, we evaluated 951 visits to LSUHSC-S for IBD (between 2000 to 2008) using non-identified patient information based on ICD-9 medical record coding (Crohn's disease 'CD'-555.0- 555.9 and ulcerative colitis 'UC'-556.0-556.9).

Results

Overall, there were more cases of CD seen than UC. UC and CD affected similar ratios of AA and Caucasian males (M) and females (F) with a rank order of WF > WM > AAF > AAM. Interestingly, in CD, we found that annual visits per person was the highest in AA M (10.7 ± 1.7); significantly higher (* -p < 0.05) than in WM (6.3 ± 1.0). Further, in CD, the female to male (F: M) ratio in AA was significantly higher (*- p < 0.05) (1.9 ± 0.2) than in Caucasians (F:M = 1.3 ± 0.1) suggesting a female dominance in AACD; no differences were seen in UC F: M ratios.

Conclusion

Although Caucasians still represent the greatest fraction of IBD (~64%), AAs with IBD made up >1/3 (36.4%) of annual IBD cases from 2000-2008 at LSUHSC-S. Further studies on genetic and environments risks for IBD risk in AAs are needed to understand differences in presentation and progression in AAs and other 'non-traditional' populations.
Similarity of Recombinant Human Perlecan Domain 1 by Alternative Expression Systems Bioactive Heterogenous Recombinant Human Perlecan D1
Authors: Ellis April L , Pan Wensheng , Yang Guang , Jones Kim , Chuang Christine , Whitelock John M , DeCarlo Arthur A
Published: September 2010

Background

Heparan sulfate glycosaminoglycans are diverse components of certain proteoglycans and are known to interact with growth factors as a co-receptor necessary to induce signalling and growth factor activity. In this report we characterize heterogeneously glycosylated recombinant human perlecan domain 1 (HSPG2 abbreviated as rhPln.D1) synthesized in either HEK 293 cells or HUVECs by transient gene delivery using either adenoviral or expression plasmid technology.

Results

By SDS-PAGE analysis following anion exchange chromatography, the recombinant proteoglycans appeared to possess glycosaminoglycan chains ranging, in total, from 6 kDa to >90 kDa per recombinant. Immunoblot analysis of enzyme-digested high MrrhPln.D1 demonstrated that the rhPln.D1 was synthesized as either a chondroitin sulfate or heparan sulfate proteoglycan, in an approximately 2:1 ratio, with negligible hybrids. Secondary structure analysis suggested helices and sheets in both recombinant species. rhPln.D1 demonstrated binding to rhFGF-2 with an apparent kDof 2 ± 0.2 nM with almost complete susceptibility to digestion by heparinase III in ligand blot analysis but not to chondroitinase digestion. Additionally, we demonstrate HS-mediated binding of both rhPln.D1 species to several other GFs. Finally, we corroborate the augmentation of FGF-mediated cell activation by rhPln.D1 and demonstrate mitogenic signalling through the FGFR1c receptor.

Conclusions

With importance especially to the emerging field of DNA-based therapeutics, we have shown here that proteoglycan synthesis, in different cell lines where GAG profiles typically differ, can be directed by recombinant technology to produce populations of bioactive recombinants with highly similar GAG profiles.
Activation of Voltage-Gated KCNQ/Kv7 Channels by Anticonvulsant Retigabine Attenuates Mechanical Allodynia of Inflammatory Temporomandibular Joint in Rats
Authors: Xu Wen , Wu Yuwei , Bi Yeping , Tan Lei , Gan Yehua , Wang KeWei
Published: September 2010

Background:

Temporomandibular disorders (TMDs) are characterized by persistent orofacial pain and have diverse etiologic factors that are not well understood. It is thought that central sensitization leads to neuronal hyperexcitability and contributes to hyperalgesia and spontaneous pain. Nonsteroidal anti-inflammatory drugs (NSAIDs) are currently the first choice of drug to relieve TMD pain. NSAIDS were shown to exhibit anticonvulsant properties and suppress cortical neuron activities by enhancing neuronal voltage-gated potassium KCNQ/Kv7 channels (M-current), suggesting that specific activation of M-current might be beneficial for TMD pain.

Results:

In this study, we selected a new anticonvulsant drug retigabine that specifically activates M-current, and investigated the effect of retigabine on inflammation of the temporomandibular joint (TMJ) induced by complete Freund's adjuvant (CFA) in rats. The results show that the head withdrawal threshold for escape from mechanical stimulation applied to facial skin over the TMJ in inflamed rats was significantly lower than that in control rats. Administration of centrally acting M-channel opener retigabine (2.5 and 7.5 mg/kg) can dose-dependently raise the head withdrawal threshold of mechanical allodynia, and this analgesic effect can be reversed by the specific KCNQ channel blocker XE991 (3 mg/kg). Food intake is known to be negatively associated with TMJ inflammation. Food intake was increased significantly by the administration of retigabine (2.5 and 7.5 mg/kg), and this effect was reversed by XE991 (3 mg/kg). Furthermore, intracerebralventricular injection of retigabine further confirmed the analgesic effect of central retigabine on inflammatory TMJ.

Conclusions:

Our findings indicate that central sensitization is involved in inflammatory TMJ pain and pharmacological intervention for controlling central hyperexcitability by activation of neuronal KCNQ/M-channels may have therapeutic potential for TMDs.
Disorganized epithelial polarity and excess trophectoderm cell fate in preimplantation embryos lacking E-cadherin
Authors: Stephenson Robert Odell , Yamanaka Yojiro , Rossant Janet
Published: September 2010

The first two cell lineages in the mouse, the surface trophectoderm (TE) and inner cell mass (ICM), are morphologically distinguishable by E3.5, with the outer TE forming a polarized epithelial layer enclosing the apolar ICM. We show here that in mouse embryos completely lacking both maternal and zygotic E-cadherin (cadherin 1), the normal epithelial morphology of outside cells is disrupted, but individual cells still initiate TE- and ICM-like fates. A larger proportion of cells than normal showed expression of TE markers such as Cdx2, suggesting that formation of an organized epithelium is not necessary for TE-specific gene expression. Individual cells in such embryos still generated an apical domain that correlated with elevated Cdx2 expression. We also show that repolarization can occur in isolated early ICMs from both wild-type and Cdx2 mutant embryos, indicating that Cdx2 is not required for initiating polarity. The results demonstrate that epithelial integrity mediated by E-cadherin is not required for Cdx2 expression, but is essential for the normal allocation of TE and ICM cells. They also show that Cdx2 expression is strongly linked to apical membrane polarization.
PEX11 family members are membrane elongation factors that coordinate peroxisome proliferation and maintenance
Authors: Koch Johannes , Pranjic Kornelija , Huber Anja , Ellinger Adolf , Hartig Andreas , Kragler Friedrich , Brocard Cécile
Published: September 2010

Dynamic changes of membrane structure are intrinsic to organelle morphogenesis and homeostasis. Ectopic expression of proteins of the PEX11 family from yeast, plant or human lead to the formation of juxtaposed elongated peroxisomes (JEPs),which is evocative of an evolutionary conserved function of these proteins in membrane tubulation. Microscopic examinations reveal that JEPs are composed of independent elongated peroxisomes with heterogeneous distribution of matrix proteins. We established the homo- and heterodimerization properties of the human PEX11 proteins and their interaction with the fission factor hFis1, which is known to recruit the GTPase DRP1 to the peroxisomal membrane. We show that excess of hFis1 but not of DRP1 is sufficient to fragment JEPs into normal round-shaped organelles, and illustrate the requirement of microtubules for JEP formation. Our results demonstrate that PEX11-induced JEPs represent intermediates in the process of peroxisome membrane proliferation and that hFis1 is the limiting factor for progression. Hence, we propose a model for a conserved role of PEX11 proteins in peroxisome maintenance through peroxisome polarization, membrane elongation and segregation.
Decrease of sialic acid residues as aneat-mesignal on the surface of apoptotic lymphocytes
Authors: Meesmann Hanna Marie , Fehr Eva-Marie , Kierschke Sonja , Herrmann Martin , Bilyy Rostyslav , Heyder Petra , Blank Norbert , Krienke Stefan , Lorenz Hanns-Martin , Schiller Martin
Published: September 2010

The silent clearance of apoptotic cells is essential for cellular homeostasis in multicellular organisms, and several mediators of apoptotic cell recognition have been identified. However, the distinct mechanisms involved are not fully deciphered yet. We analyzed alterations of the glycocalyx on the surfaces of apoptotic cells and its impact for engulfment. After apoptosis induction of lymphocytes, a decrease of α2,6-terminal sialic acids and sialic acids in α2,3-linkage with galactose was observed. Similar changes were to be found on the surface of apoptotic membrane blebs released during early stages of apoptosis, whereas later released blebs showed no impaired, but rather an increased, exposure of sialic acids. We detected an exposure of fucose residues on the surface of apoptotic-cell-derived membrane blebs. Cleavage by neuraminidase of sialic acids, as well as lectin binding to sialic acids on the surfaces, enhanced the engulfment of apoptotic cells and blebs. Interestingly, even viable lymphoblasts were engulfed in an autologous cell system after neuraminidase treatment. Similarly, the engulfment of resting apoptotic lymphocytes was augmented after neuraminidase treatment. However, the engulfment of resting viable lymphocytes was not significantly enhanced after neuraminidase treatment. Our findings support the importance of the glycocalyx, notably the terminal sialic acids, in the regulation of apoptotic cell clearance. Thus, depending on cell type and activation status, changes in surface glycosylation can either directly mediate cellular engulfment or enhance phagocytosis by cooperation with further engulfment signals.
AT-1 is the ER membrane acetyl-CoA transporter and is essential for cell viability
Authors: Jonas Mary Cabell , Pehar Mariana , Puglielli Luigi
Published: September 2010

The transient or permanent modification of nascent proteins in the early secretory pathway is an essential cellular function that ensures correct folding and maturation of membrane and secreted proteins. We have recently described a new form of post-translational regulation of the membrane protein β-site APP cleaving enzyme 1 (BACE1) involving transient lysine acetylation in the lumen of the endoplasmic reticulum (ER). The essential components of this process are two ER-based acetyl-CoA:lysine acetyltransferases, ATase1 and ATase2, and a membrane transporter that translocates acetyl-CoA into the lumen of the ER. Here, we report the functional identification of acetyl-CoA transporter 1 (AT-1) as the ER membrane acetyl-CoA transporter. We show that AT-1 regulates the acetylation status of ER-transiting proteins, including the membrane proteins BACE1, low-density lipoprotein receptor and amyloid precursor protein (APP). Finally, we show that AT-1 is essential for cell viability as its downregulation results in widespread cell death and induction of features characteristic of autophagy.
Src-dependent phosphorylation of ROCK participates in regulation of focal adhesion dynamics
Authors: Lee Hsiao-Hui , Tien Sui-Chih , Jou Tzuu-Shuh , Chang Yuan-Chen , Jhong Jheng-Guang , Chang Zee-Fen
Published: September 2010

When a cell migrates, the RhoA–ROCK-mediated contractile signal is suppressed in the leading edge to allow dynamic adhesions for protrusion. However, several studies have reported that RhoA is indeed active in the leading edge of a migrating cell during serum stimulation. Here, we present evidence that regulation of ROCKII phosphorylation at the Y722 site in peripheral focal contacts is crucial for controlling the turnover of the focal adhesion (FA) complex uncoupled from RhoA activation during serum-stimulated migration. However, this phosphorylation control is dispensable for migration when RhoA is downregulated in cells treated with platelet-derived growth factor (PDGF). We further present evidence that ROCKII is phosphorylated by Src in FAs and this phosphorylation event decreases RhoA binding activity of ROCKII. Lack of this regulatory control leads to sustained myosin-mediated contractility and FA elongation during lysophosphatidic acid (LPA) stimulation. Altogether, our data suggest that Src-dependent ROCKII phosphorylation provides a means of tuning contractility required for FAs dynamics when RhoA is active.
Assessment of Thread-Cutting Strategies to Enable Damage-Tolerant Surfaces on an Advanced Ni-Based Aerospace Superalloy
Authors: Marinescu I , Axinte D , Herbert C , McGourlay J , Withers P J
Published: September 2010

The global aerospace manufacturing industry is continually developing higher strength superalloys to increase engine efficiency. With this comes the challenge of machining these difficult-to-cut materials at high productivity rates and increased surface accuracy requirements. Despite the technical challenges faced, it seems that the research area of thread cutting in aerospace alloys has generally been neglected. This paper addresses reports on a critical assessment of two thread-cutting methods (i.e. tapping and thread milling) applied to a ‘next-generation’ high-temperature Ni-based aerospace superalloy. Carrying out tool life tests revealed tapping (of small thread dimensions) to be particularly difficult to perform due to high and continuous friction incurred at the cutting edge—workpiece interface, which resulted in various surface anomalies (i.e. severe plastic deformation, laps). The optimized thread-milling strategies have, however, shown a significant improvement in tool life and surface integrity of the machined component. To support the understanding of the performances for the investigated thread-making methods, this paper discusses the interrelationship between the specific characteristics of thread tapping and milling sensory signals (cutting forces and torques) with further associations on the quality (metallurgical integrity and residual stresses) of threaded surfaces in notoriously difficult-to-cut Ni-based superalloys.
Application of Wavelet Transform of Acoustic Emission and Cutting Force Signals for Tool Condition Monitoring in Rough Turning of Inconel 625
Authors: Jemielniak K , Kossakowska J , Urbański T
Published: September 2010

Nickel-based superalloys are widely used in the aircraft industry since they are exceptionally thermal resistant, retaining their mechanical properties at temperatures of up to 700 °C. On the other hand, since they are very difficult to machine, tool life is typically short and can finish abruptly. As catastrophic tool failure can destroy an expensive workpiece, automatic tool condition monitoring (TCM) has become particularly critical. This paper presents an application of the wavelet packet transform (WPT) for extracting useful TCM features from the cutting forces and acoustic emission (AE) signals during rough turning of Inconel 625. New, improved methods of signal feature (SF) relevancy evaluation were proposed based on determination and correlation coefficients. Out of several SFs calculated from bandpass signals, the most useful for TCM were automatically selected. The selected features were used for tool condition monitoring.
Effect of geometry on magneto-convection in a square enclosure filled with a low Prandtl number fluid
Authors: Sheikhzadeh G A , Fattahi A , Mehrabian M A , Pirmohammadi M
Published: September 2010

Numerical simulation of magneto-convection heat transfer and fluid flow is analysed in an enclosure with a centrally located adiabatic square-shaped body using finite volume method. The enclosure's opposite walls (right and left) are heated and cooled, respectively, and the other walls are adiabatic. The effects of Rayleigh number ( Ra = 103—106), Hartmann number ( Ha = 0, 50, and 100), and ratio of the body's length to the enclosure's length ( W/ L = 0.1—0.9) on the temperature and flow fields are analysed. The Prandtl number is assumed to be 0.02 representing a liquid metal. In the casting process, when a magnetic field is introduced, the convection strength is suppressed and this operation leads to a fine grain structure. To find how the average Nusselt number changes, the average vertical velocity in a certain location is also calculated. It was observed that the body's length affects the flow and temperature fields. It was also found that with increasing the W/ L, heat transfer decreased at low Rayleigh numbers but increased at the beginning and then decreased at high Rayleigh numbers.
Prevention of helical gear tooth damage in wind turbine generator: A case study
Authors: Sankar S , Nataraj M
Published: September 2010

The transmission error between the driving and driven gears originating because of manufacturing error or misalignment in the gearbox assembly causes noise and vibrations during the functioning of the gearbox. This research article discusses a novel method to prevent tooth damage in the helical gear due to transmission error by providing tip relief on the gear tooth and introducing a combination of epi-cycloid and involute profiles called composite profile for the gear tooth. Analysis is carried out using finite-element analysis package for the existing involute as well as the modified composite helical gear pair to evaluate the performance. The study reveals that the modified design (tip relief with composite profile) is superior to the existing involute gear for windmill applications because the wind turbine generators are subjected to fluctuating wind force, sudden grid drops, failure of pitching, braking, etc.
A Novel Recompression S-CO2 Brayton Cycle with Pre-Cooler Exergy Utilization
Authors: Yari M , Sirousazar M
Published: September 2010

This study examines the performance of a novel recompression supercritical CO2 (S-CO2) Brayton cycle of nuclear power plant with pre-cooler exergy utilization, which uses a transcritical CO2 cycle to enhance the performance of this new cycle. More attention was paid to irreversibilities generated in the combined cycle. Individual models were developed for each component through the application of the first and second laws of thermodynamics. The effects of the turbine inlet temperature, compressor pressure ratio, maximum cycle pressure, main compressor inlet temperature, and also environment temperature on the first- and second-law efficiencies and also on the exergy destruction of the S-CO2 and the presented new S-CO2 recompression cycles were studied. Finally, the recompression S-CO2 cycles were thermodynamically optimized using the Engineering Equation Solver software. Based on identical operating conditions, a comparison between the new S-CO2 and a simple S-CO2 cycle was also performed. It was found that both the first- and second-law efficiencies of the new S-CO2 cycle are about 5.5 per cent to 26 per cent higher than that of the simple S-CO2 cycle. The exergy destruction of the new S-CO2 cycle is also about 6.7 per cent to 28.8 per cent lower than that of the simple S-CO2 cycle.
Analysis of the oil supply system of a high-pressure shell scroll compressor
Authors: Liu H R , Zhao Y Y , Wang L , Sun S H , Li L S
Published: September 2010

The supply of lubrication oil has a great influence on the reliability and efficiency of a scroll compressor, because oil plays a role in lubrication, sealing, and heat transfer in the compressor. In this work, a comprehensive steady and transient analysis on the oil supply system of a high-pressure shell scroll compressor was carried out using a commercial computational fluid dynamics (CFD) program. Various parameters, including pressure difference, compressor rotation speed, oil temperature, bearing clearance, and diameter of the oil gallery, were investigated to find the relations with oil flowrate. Among them, oil temperature and bearing clearance are indicated as the most sensitive, and pressure difference follows. Compressor rotation speed and diameter of the oil gallery are insensitive. Some hydrodynamic parameters can also be obtained in detail, such as pressure drop and oil flow velocity. This CFD analysis has proved to be helpful for the design and optimization of an oil supply system in a scroll compressor.
Effects of a fogging system on a combined cycle performance
Authors: Yilmazoğlu M Z
Published: September 2010

Combined cycle power plants consist of a gas cycle, which uses gas turbines to generate electricity, and a water–steam cycle, which uses steam turbines to generate electricity. In gas turbine power plants, operation performance is the function of ambient air temperature, pressure, and humidity. Electricity consumption increases in summer seasons due to increasing cooling demand to satisfy thermal comfort conditions. Ambient air temperature affects gas turbine power output and peaking problem occurs at higher temperatures in the electricity grid. Inlet air cooling is a method to increase the power output of a gas cycle by decreasing the temperature of inlet air to the cycle. Inlet air cooling in gas turbine power plants can be obtained by the evaporative cooling method, fogging, absorption, and mechanical compression chillers mainly. Evaporative media or fogging system increases the relative humidity up to 95 per cent and as a result inlet air temperature decreases and mass flowrate to the compressor increases. In this study, a combined cycle power plant is considered with a fogging system and a parametric study is performed to analyse the effects of the ambient temperature and the humidity on the combined cycle performance. When a fogging system is applied to the cycle, the net power generation and the net fuel input of the combined cycle are increased by 8.3 per cent. Besides, plant auxiliaries and water consumption is also increased by 0.55 per cent and 4.2 per cent, respectively. However, energy and exergy efficiencies are decreased by 0.2 per cent in the case of applying a fogging system.
Theoretical and Experimental Study on the Performance of CO2 Hermetic Scroll Compressor
Authors: Hao J Y , Zhao Y Y , Li L S , Wang Z Z , Shu P C
Published: September 2010

Natural refrigerant CO2 is considered as one of the ideal alternative refrigerants, and CO2 compressors are the core components of refrigeration system. A simulation program was established to predict the performance of the CO2 hermetic scroll compressor in this article. The experimental and simulation results show that as the pressure ratio increases, the volumetric and indicated efficiencies decrease. Both of the efficiencies increase with the increased compressor speed. The influence of the compressor speed on the volumetric efficiency at a higher pressure ratio is more significant than the lower one. The increment of both efficiencies decrease gradually as the compressor speed rises. The superheat has little impact on the volumetric and indicated efficiencies. The maximum volumetric efficiency is 0.84 and the maximum indicated efficiency is 0.80. The deviations of the simulation and experimental results are within ±5 per cent.
Thermodynamic performance evaluation of gas turbine cycle with transpiration cooling of blades using air vis-à-vis steam
Authors: Kumar S , Singh O
Published: September 2010

Gas turbine blade cooling has major importance in improving the gas turbine cycle performance by an increase in turbine inlet temperature (TIT). Among different cooling techniques available, the convection and film cooling are the most widely used techniques. Studies have shown that transpiration cooling technique uses the coolant more effectively than the film and convection cooling techniques. The present study deals with the performance evaluation of gas turbine cycle with transpiration cooling of gas turbine blades. A comparison has been made using air and steam as cooling mediums. Cycle performance has been evaluated in terms of overall efficiency and specific power. Literature shows that in existing gas turbine blade cooling models the effect of radiation from higher temperature gases is usually neglected. However, the radiation occurs due to presence of high-temperature combustion products primarily comprising of CO2, NO x, and H2O. The present article evaluates the gas cycle performance taking radiation effect into account. A computer code ‘GTANALYS’ has been developed to perform all the computations. The results show that for the given conditions steam appears to be better coolant compared to air. For a TIT of 1700 K and cycle pressure ratio of 32, the steam-cooled cycle efficiency is about 2.58 per cent higher than air-cooled cycle efficiency.
Experimental Investigation of the Influence of Fouling on Compressor Cascade Characteristics and Implications for Gas Turbine Engine Performance
Authors: Fouflias D , Gannan A , Ramsden K , Pilidis P , Mba D , Teixeira J , Igie U , Lambart P
Published: September 2010

This article describes the findings of a study which examined the influence of fouling on the behaviour of a cascade and by making use of these results the performance implications for gas turbine engines of exposure to airborne foulants.

A suction-type compressor cascade tunnel with a plenum chamber was employed for investigating fouling blade effects. The tests showed that such a testing arrangement allows the extraction of pressure and corrected velocity distribution data downstream of the blades that is comparable with what can be obtained from blow-type cascade tunnels.

This study presents experimental results for smooth clean cascade blades and for uniformly fouled blades. For all the cases considered, mid-span-corrected velocity distributions and pressure losses taken one chord downstream of the blades were investigated in order to identify the effects of fouling on the blades. The result of fouling on exit flow angle was investigated as well.

In the present study, cascade clean and fouled cases were used to predict real engine performance. Results are obtained in terms of stage polytropic efficiency, thermal efficiency, useful power, and compressor efficiency deterioration. Roughening the cascade blades uniformly with particles of 254 μ m size, the compressor efficiency dropped by 7.7 percentage points.
Composite Process Models Used in Stock Tank Quantity Prediction for Sugar Mill Crystallization Stage Knowledge-Based Supervisory Support
Authors: Dodd R , Chiou A , Broadfoot R , Yu X
Published: September 2010

The present paper proposes the component process models for a knowledge-based supervisory support system designed to provide expert knowledge in the control and management of a sugar mill crystallization stage. Forecasting stock tank quantities, within the sugar factory crystallization stage, is beneficial to ensure that there are sufficient quantities of stock materials to allow completion of production schedules without disruption. It is shown that integration of projected vacuum pan feed rates with syrup rate production models and vacuum pan phase detection models allows forecasting of stock tank quantities for syrup and molasses in order to work towards the goal of forewarning of potential problems with the current operating strategies and advising corrective procedures. These industrial process models form an integral part of an overall pan stage knowledge-based supervisory support system to assist in providing a better decision-making strategy for crystallization stage operations.
Time-Optimal Task Scheduling for Two Robotic Manipulators Operating in a Three-Dimensional Environment
Authors: Xidias E K , Zacharia P Th , Aspragathos N A
Published: September 2010

The present paper introduces a method for determining the optimal task scheduling for a two-robot work cell. This problem is reminiscent of the classic Travelling Salesman Problem (TSP), but the measure to be optimized is the time instead of the distance. In addition, this is a much more complex problem, since it involves two robots (salesmen), which have to visit different task-points (cities) considering the multiplicity of the robots' inverse kinematics. The optimization problem addressed in this work concerns the determination of the (near-)optimum sequence of task-points that should be visited by each one of the two robots while ensuring minimum total cycle time and collision avoidance among their links. The proposed approach is based on genetic algorithms and a special encoding is used to incorporate the division of the task-points for both robots and the multiple solutions of the inverse kinematics. The method was tested in different scenarios and the experimental results demonstrated the efficiency and effectiveness of the proposed approach.
Influence of Cavitation in the Injection Nozzle on Combustion in Diesel Engines
Authors: Fimml W , Chmela F G , Pirker G , Wimmer A
Published: September 2010

This paper is concerned with the influence of cavitation in the injection nozzle on combustion in diesel engines. After an overview of the fundamental definitions to characterize nozzles — where above all the injection pressure, the back pressure, the injection mass flow, and the spray momentum through the nozzle as well as the geometry play a role — the difference between a cavitating and a non-cavitating nozzle will be clarified both theoretically and based on engine measurements. To observe the influence of cavitation on combustion in isolation, a cavitating and a non-cavitating nozzle were designed in such a way that they possessed the same mass flow and the same nozzle discharge velocity. In addition to the manufacturer's measurement, the nozzles were measured using a combined flowrate—spray momentum device at levels of injection pressure and back pressure close to those in an engine. A single-cylinder research engine with a modern common rail injection system served as the test engine for the experiments. The experiments revealed striking differences in emission levels. Especially notable are the differences in the soot values. To explore in more detail these differences between the cavitating and non-cavitating nozzle, optical investigations were conducted in an injection chamber. CCD high-speed imaging was used to visualize mixture formation of the two different nozzles.
Evaluation of elicitation methods to quantify Bayes linear models
Authors: Revie M , Bedford T , Walls L
Published: September 2010

The Bayes linear methodology allows decision makers to express their subjective beliefs and adjust these beliefs as observations are made. It is similar in spirit to probabilistic Bayesian approaches, but differs as it uses expectation as its primitive. While substantial work has been carried out in Bayes linear analysis, both in terms of theory development and application, there is little published material on the elicitation of structured expert judgement to quantify models. This paper investigates different methods that could be used by analysts when creating an elicitation process. The theoretical underpinnings of the elicitation methods developed are explored and an evaluation of their use is presented. This work was motivated by, and is a precursor to, an industrial application of Bayes linear modelling of the reliability of defence systems. An illustrative example demonstrates how the methods can be used in practice.
Forecasting seismic damage scenarios of residential buildings from rough inventories: A case-study in the Abruzzo Region (Italy)
Authors: Bernardini A , Lagomarsino S , Mannella A , Martinelli A , Milano L , Parodi S
Published: September 2010

A model is presented for forecasting the seismic vulnerability and probability of damage of ordinary building types, as a function of the local macroseismic intensity or correlated parameters of the ground motion. The conventional definitions of damage degrees and vulnerability classes of the building types have been assumed according to the EMS98 macroseismic scale. The model allows damage scenarios to be evaluated in selected areas where an inventory of the buildings, containing at least some qualitative information is available, in order to recognize, for the different types, the corresponding vulnerability class or at least the probability of membership to the vulnerability classes. The epistemic uncertainty of the qualitative definitions suggested by the scale for frequencies of damage is taken into account through the formalizing of the imprecise probabilities, i.e. through convex sets of possible probability distributions on the discrete space of the damage degrees, with particular reference to their description by means of random sets, both non-consonant and consonant (fuzzy sets). It is thus possible to obtain upper/lower bounds of the expectation of interesting functions of the damage degrees (e.g. number of victims, unusable buildings, and collapsed buildings). The model has been applied to the entire area of the Abruzzo Region (Central Italy), using the inventory of buildings recorded by the National Statistics Agency. Some comparisons are given between the expected damage and that observed after the strong earthquake that in April 2009 struck a more restricted zone of the region (the town of L'Aquila and surrounding countryside).
Reliability assessment of explosive material based on penalty tests: An info-gap approach
Authors: Mirer T , Ben-Haim Y
Published: September 2010

A method is developed for experimental assessment of the reliability of a system with a stringent safety requirement: explosive material. The focus is on the analysis and management of both statistical variability of measurements and non-probabilistic uncertainty in probability distributions (distributional uncertainty). Info-gap theory is used to model the distributional uncertainty in the probability distribution function of the threshold for actuation of the explosive material. The quantitative analysis and the qualitative judgements which accompany the certification of safety are studied. A proposition is proven asserting that the info-gap robustness function, for the class of problems examined, is independent of the experimental design over virtually all of its range.
Injection-induced sciatic nerve injury in Ugandan children
Authors: Sitati Fred Chuma , Naddumba Edward , Beyeza Tito
Published: September 2010

In developing countries, sciatic nerve injury following gluteal intramuscular injection is a persistent problem. A study over 6 months involving 133 children seen in Mulago hospital with acute flaccid paralysis revealed 124 (93%) children with injection-induced sciatic nerve injury. The identity of the drug in 79 cases (59.4%) was quinine. It is recommended that the gluteal region should not be used as an intramuscular injection site in children.
The challenge of patients with severe psychiatric illness who do not access care – a way forward
Authors: John Sushil Mathew , Venkatesan Sankarapandian , Tharyan Anna , Bhattacharji Sara
Published: September 2010

Psychiatric illnesses are a significant cause of morbidity all over the world. In India many people with mental disorders are unable to access psychiatric care for a variety of reasons.

This article describes the successful management of a person with schizophrenia in the community through a primary care team in liaison with psychiatrist services.
Sensitivity Analysis of Risk Tolerance
Authors: Sandvik Bjørn , Thorlund-Petersen Lars
Published: September 2010

For a risk-averse decision maker with exponential utility facing a decision between two investments X and Y, there may exist more than one critical value of risk tolerance for which the decision is reversed from one investment to the other. Our main result establishes that if Y is preferred to X by all risk-seeking decision makers, then there is at most one such critical value. We extend this result to linear plus exponential utility functions. The results reduce the input required from a decision maker.
From the Editor…
Authors: Keller L. Robin
Published: September 2010

In our first article, Samuel D. Bond, Kurt A. Carlson, and Ralph L. Keeney address the important stage of decision problem formulation in “Improving the Generation of Decision Objectives.” Next, Charles M. Harvey and Lars Peter Østerdal develop “Cardinal Scales for Health Evaluation.” We then move to consideration of risk taking and risk perception. In our third article, Alen Nosić and Martin Weber report their experimental study on “How Riskily Do I Invest? The Role of Risk Attitudes, Risk Perceptions, and Overconfidence.” In the next article, Michel Denuit and Louis Eeckhoudt provide results on “Bivariate Stochastic Dominance and Substitute Risk-(In)dependent Utilities.” In our final article, Bjørn Sandvik and Lars Thorlund-Petersen derive results on “Sensitivity Analysis of Risk Tolerance.” At the end of this article are some recent journal accomplishments, including the coverage in the Social Sciences Citation Index.
Averaging Principles for a Diffusion-Scaled, Heavy-Traffic Polling Station with K Job Classes
Authors: Jennings Otis B.
Published: September 2010

This paper provides heavy traffic limit theorems for a polling station serving jobs from K exogenous renewal arrival streams. It is a standard result that the limiting diffusion-scaled total workload process is semimartingale reflected Brownian motion. For polling stations, however, no such limit exists in general for the diffusion-scaled, K-dimensional queue length or workload vector processes. Instead, we prove that these processes admit averaging principles, the natures of which depend on the service discipline employed at the polling station. Parameterized families of exhaustive and gated service disciplines are investigated.

Each policy under consideration has K stochastic matrices associated with it—one for each job class—that describe the transition of the workload vector while a given job class is being polled. These matrices give rise to K probability vectors that are vertices of a K - 1-simplex. Loosely speaking, each point of this simplex acts as an instantaneous lifting operator, converting the one-dimensional limiting total workload process to the K-dimensional workload vector. The averaging principles—needed because the workload vector traverses a Hamiltonian cycle over K edges of the simplex infinitely fast under diffusion scaling—are limits of cumulative cost functions of the diffusion-scaled workload vector, evaluated over a fixed time interval. The “averaging” takes place over the edges of the simplex.
Maximal Lattice-Free Convex Sets in Linear Subspaces
Authors: Basu Amitabh , Conforti Michele , Cornuéjols Gérard , Zambelli Giacomo
Published: September 2010

We consider a model that arises in integer programming and show that all irredundant inequalities are obtained from maximal lattice-free convex sets in an affine subspace. We also show that these sets are polyhedra. The latter result extends a theorem of Lovász characterizing maximal lattice-free convex sets in ℝn.
Simultaneous analysis of coupled data matrices subject to different amounts of noise
Authors: Wilderjans Tom F. , Ceulemans Eva , Van Mechelen Iven , van den Berg Robert A.
Published: September 2010

In many areas of science, research questions imply the analysis of a set of coupled data blocks, with, for instance, each block being an experimental unit by variable matrix, and the variables being the same in all matrices. To obtain an overall picture of the mechanisms that play a role in the different data matrices, the information in these matrices needs to be integrated. This may be achieved by applying a data‐analytic strategy in which a global model is fitted to all data matrices simultaneously, as in some forms of simultaneous component analysis (SCA). Since such a strategy implies that all data entries, regardless the matrix they belong to, contribute equally to the analysis, it may obfuscate the overall picture of the mechanisms underlying the data when the different data matrices are subject to different amounts of noise. One way out is to downweight entries from noisy data matrices in favour of entries from less noisy matrices. Information regarding the amount of noise that is present in each matrix, however, is, in most cases, not available. To deal with these problems, in this paper a novel maximum‐likelihood‐based simultaneous component analysis method, referred to as MxLSCA, is proposed. Being a stochastic extension of SCA, in MxLSCA the amount of noise in each data matrix is estimated and entries from noisy data matrices are downweighted. Both in an extensive simulation study and in an application to data stemming from cross‐cultural emotion psychology, it is shown that the novel MxLSCA strategy outperforms the SCA strategy with respect to disclosing the mechanisms underlying the coupled data.
Distance Graphs from p-adic Norms
Authors: Kang Jeong-Hyun , Maharaj Hiren
Published: September 2010

Given a set
A Note on Stirling Series
Authors: Kuba Markus , Prodinger Helmut
Published: September 2010

We study sums
Alternative Proofs on the 2-adic Order of Stirling Numbers of the Second Kind
Authors: Lengyel Tamás
Published: September 2010

An interesting 2-adic property of the Stirling numbers of the second kind
Congruences for Overpartition k-tuples
Authors: Chen Shi-Chao
Published: September 2010

An
Decomposing tensor products and exterior and symmetric squares
Authors: Barry Michael J. J.
Published: September 2010

We describe a new algorithm for decomposing tensor products of indecomposable
Entkopplungsregelung und Reibungskompensation für einen Roboter mit elastischen verkoppelten Gelenken
Authors: Le-Tien Luc , Albu-Schäffer Alin , Janschek Klaus , Hirzinger Gerd
Published: September 2010

Dieser Beitrag beschreibt die Regelung und Reibungskompensation von Robotern mit elastischen und differentiell getriebenen Gelenken (implementiert am Beispiel des DLR-Medizinroboters). Unter Berücksichtigung der Gelenkverkopplung wird ein MIMO-Zustandsregler (multi-input-multi-output) für die Doppelgelenkstruktur des Medizinroboters eingeführt, der auf der Rückführung der gemessenen Motorpositionen, abtriebsseitigen Drehmomente und deren Ableitungen basiert. Um die Positioniergenauigkeit des Roboters zu verbessern, wird zusätzlich ein Störgrößenbeobachter für die Reibungskompensation entwickelt. Es wird gezeigt, dass der Roboter mit dem MIMO-Zustandsregler und dem Störgrößenbeobachter global asymptotisch stabil ist. Abschließend werden experimentelle Ergebnisse mit dem DLR-Medizinroboter zur Validierung des Ansatzes vorgestellt.
Mehr Systematik für den Anlagenbau und das industrielle Lösungsgeschäft — Gesteigerte Effizienz durch Domain Engineering
Authors: Jazdi Nasser , Maga Camelia , Göhner Peter , Ehben Thomas , Tetzner Thilo , Löwen Ulrich
Published: September 2010

Der Beitrag beschreibt die Herausforderungen im industriellen Lösungsgeschäft aus Betreiber- und Anbietersicht und erläutert ein zur Bewältigung dieser Herausforderungen mögliches Prinzip: Die Aufteilung in projektabhängiges und projektunabhängiges Engineering. Auf dieser Basis wird ein neuer Engineering-Ansatz zur Realisierung des projektunabhängigen Engineering vorgestellt. Der Ansatz wird im Rahmen einer Kooperation zwischen dem Institut für Automatisierungs- und Softwaretechnik (IAS) der Universität Stuttgart und der Siemens AG entwickelt und erprobt.
Entwurf nichtlinearer Beobachter mit linearer und näherungsweise linearer Fehlerdynamik
Authors: Röbenack Klaus
Published: September 2010

Der Beobachterentwurf mittels exakter Linearisierung ist der Fachwelt seit rund 25 Jahren bekannt. Aufgrund restriktiver Existenzbedingungen bzw. einer aufwendigen Berechnung ist dieser sehr elegante Ansatz in der regelungstechnischen Praxis kaum anzutreffen. Im Beitrag werden zunächst Existenzbedingungen und Berechnungsmethoden rekapituliert. Anschließend geht der Beitrag auf den erweiterten Luenberger-Beobachter ein, welcher auf einer lokalen Taylorlinearisierung basiert und wesentlich leichter zu berechnen ist. Zu diesem Beobachter werden Verallgemeinerungen entwickelt und globale Konvergenzbedingungen angegeben.
Modellierung und Simulation von Kraftwerksblöcken
Authors: Kutzner Rüdiger , Bennauer Martin , Hopp Stefan , Joswig Frank , Könemund Martin , Lerch Edwin , Lösing Martin , Meinecke Carsten , Wenzel Andree , Werthes Heribert
Published: September 2010

Der Beitrag beschreibt die Modellbildung und Validierung eines Dampfkraftwerks mit seinen Regeleinrichtungen. Die Verwendung simulatorischer Methoden entlastet die mechanischen und elektrischen Komponenten von Lebensdauer verkürzenden Optimierungen im Betrieb. Die Überprüfung dynamischer Vorgänge anhand vorliegender Messergebnisse liefert den Nachweis der Modellgültigkeit. Anlagenschonend kann somit der Nachweis der Funktionsfähigkeit auch selten benötigter Regelungs- und Anlagenkomponenten erbracht werden.
A maximal inequality for skew Brownian motion
Authors: Zhitlukhin Mikhail V.
Published: September 2010

We prove a maximal inequality for skew Brownian motion. This result generalizes similar inequalities for standard Brownian motion ([2]) and its modulus ([3, 4]). The proof relies on the solution to an optimal stopping problem.