bluuebunny/crossref_metadata_2025 huggingface dataset:
ELF score ≥9.8 indicates advanced hepatic fibrosis and is influenced by age, steatosis and histological activity
Authors: Fagan Kevin J. , Pretorius Carel J. , Horsfall Leigh U. , Irvine Katharine M. , Wilgen Urs , Choi Kihoon , Fletcher Linda M. , Tate Jill , Melino Michelle , Nusrat Sharmin , Miller Gregory C. , Clouston Andrew D. , Ballard Emma , O'Rourke Peter , Lampe Guy , Ungerer Jacobus P. J. , Powell Elizabeth E.
Published: December 2014

Background & Aims

There is increasing need to identify individuals with advanced liver fibrosis, who are at risk of complications such as hepatocellular carcinoma. The commercially available enhanced liver fibrosis (ELF) test provides a non‐invasive assessment of fibrosis severity. This study was designed to determine the diagnostic accuracy of the manufacturer's cut‐off value (≥9.8) in identifying advanced fibrosis.

Methods

The relationship between ELF score and fibrosis was examined using serum collected at time of liver biopsy for investigation of liver disease, particularly viral hepatitis. Fibrosis was staged using a modified METAVIR score. If available, liver tissue was recut and stained with Sirius red to determine collagen proportional area (CPA) and subsinusoidal fibrosis (SSF).

Results

Enhanced liver fibrosis score ≥9.8 had a sensitivity of 74.4% and specificity 92.4% for detecting advanced fibrosis. In the whole cohort (n = 329), ELF score was more likely to incorrectly classify individuals if age was ≥45 years and METAVIR inflammatory grade was 2 or 3 (adjusted OR, odds ratio 3.71 and 2.62 respectively). In contrast, ELF score was less likely to misclassify individuals in the presence of steatosis (OR 0.37). Neither SSF nor CPA explained the discordance in ELF score for patients with or without advanced fibrosis.

Conclusion

Although ELF score ≥9.8 reliably identifies advanced fibrosis in patients with chronic liver disease, both age and inflammatory activity need to be considered when interpreting the result. Importantly, ELF score performed well in the presence of steatosis and could thus be helpful in the assessment of fatty liver disease.
Non‐invasive assessment of liver fibrosis in C282Y homozygous HFE hemochromatosis
Authors: Legros Ludivine , Bardou‐Jacquet Edouard , Latournerie Marianne , Guillygomarc'h Anne , Turlin Bruno , Le Lan Caroline , Désille Yoann , Lainé Fabrice , Moirand Romain , Brissot Pierre , Deugnier Yves , Guyader Dominique
Published: December 2014

Background & Aims

C282Y homozygotes with serum ferritin (SF) levels >1000 μg/L and/or increased serum transaminase levels are at risk of severe F3/F4 fibrosis. Current practical guidelines recommend liver biopsy in such individuals. This prospective observational cohort study aimed to evaluate non‐invasive alternative means such as hyaluronic acid (HA) and transient elastography (TE) for the assessment of severe fibrosis in patients with SF >1000 μg/L or elevated transaminases.

Methods

Between September 2005 and April 2013, 77 patients diagnosed C282Y homozygotes underwent a liver biopsy because of SF >1000 μg/L and/or increased transaminases according to current guidelines, with concomitant TE. All of them had clinical and biological evaluation, including HA measurement in 52 cases.

Results

A total of 19.5% of patients had F3–F4 severe fibrosis. HA was higher in patients with severe fibrosis, but did not accurately predict severe fibrosis. TE was significantly higher in patients with severe fibrosis (17.2 vs. 4.9 kPa; P < 0.05) and was able to accurately predict fibrosis stage in 47/61 (77%) patients with valid measurement using a lower threshold of 6.4 kPa and an upper threshold of 13.9 kPa. Efficient assessment of severe fibrosis was not possible in patients with intermediate TE values.

Conclusion

An algorithm that successively employed SF and TE can accurately classify severe fibrosis in 61% of patients, restricting the need for liver biopsy to the 39% of patients with intermediate or unvalid TE values. This algorithm should be validated in independent cohorts before extended use.
MODEL‐INDEPENDENT LOWER BOUND ON VARIANCE SWAPS
Authors: Kahalé Nabil
Published: December 2014

It is well known that, under a continuity assumption on the price of a stock S, the realized variance of S for maturity T can be replicated by a portfolio of calls and puts maturing at T. This paper assumes that call prices on S maturing at T are known for all strikes but makes no continuity assumptions on S. We derive semiexplicit expressions for the supremum lower bound on the hedged payoff, at maturity T, of a long position in the realized variance of S. Equivalently, is the supremum strike K such that an investor with a long position in a variance swap with strike K can ensure a nonnegative payoff at T. We study examples with constant implied volatilities and with a volatility skew. In our examples, is close to the fair variance strike obtained under the continuity assumption.
ON THE MARTINGALE PROPERTY IN STOCHASTIC VOLATILITY MODELS BASED ON TIME‐HOMOGENEOUS DIFFUSIONS
Authors: Bernard Carole , Cui Zhenyu , McLeish Don
Published: December 2014

Lions and Musiela give sufficient conditions to verify when a stochastic exponential of a continuous local martingale is a martingale or a uniformly integrable martingale. Blei and Engelbert and Mijatović and Urusov give necessary and sufficient conditions in the case of perfect correlation (). For financial applications, such as checking the martingale property of the stock price process in correlated stochastic volatility models, we extend their work to the arbitrary correlation case (). We give a complete classification of the convergence properties of both perpetual and capped integral functionals of time‐homogeneous diffusions and generalize results in Mijatović and Urusov with direct proofs avoiding the use of separating times (concept introduced by Cherny and Urusov and extensively used in the proofs of Mijatović and Urusov).
LOCAL VARIANCE GAMMA AND EXPLICIT CALIBRATION TO OPTION PRICES
Authors: Carr Peter , Nadtochiy Sergey
Published: December 2014

In some options markets (e.g., commodities), options are listed with only a single maturity for each underlying. In others (e.g., equities, currencies), options are listed with multiple maturities. In this paper, we analyze a special class of pure jump Markov martingale models and provide an algorithm for calibrating such models to match the market prices of European options with multiple strikes and maturities. This algorithm matches option prices exactly and only requires solving several one‐dimensional root‐search problems and applying elementary functions. We show how to construct a time‐homogeneous process which meets a single smile, and a piecewise time‐homogeneous process which can meet multiple smiles.
Multicollinearity in spatial genetics: separating the wheat from the chaff using commonality analyses
Authors: Prunier J. G. , Colyn M. , Legendre X. , Nimon K. F. , Flamand M. C.
Published: December 2014

Direct gradient analyses in spatial genetics provide unique opportunities to describe the inherent complexity of genetic variation in wildlife species and are the object of many methodological developments. However, multicollinearity among explanatory variables is a systemic issue in multivariate regression analyses and is likely to cause serious difficulties in properly interpreting results of direct gradient analyses, with the risk of erroneous conclusions, misdirected research and inefficient or counterproductive conservation measures. Using simulated data sets along with linear and logistic regressions on distance matrices, we illustrate how commonality analysis (CA), a detailed variance‐partitioning procedure that was recently introduced in the field of ecology, can be used to deal with nonindependence among spatial predictors. By decomposing model fit indices into unique and common (or shared) variance components,CAallows identifying the location and magnitude of multicollinearity, revealing spurious correlations and thus thoroughly improving the interpretation of multivariate regressions. Despite a few inherent limitations, especially in the case of resistance model optimization, this review highlights the great potential ofCAto account for complex multicollinearity patterns in spatial genetics and identifies future applications and lines of research. We strongly urge spatial geneticists to systematically investigate commonalities when performing direct gradient analyses.
Associations of dietary intake and plasma concentrations of eicosapentaenoic and docosahexaenoic acid with prenatal depressive symptoms in Japan
Authors: Shiraishi Mie , Matsuzaki Masayo , Yatsuki Yuko , Murayama Ryoko , Severinsson Elisabeth , Haruna Megumi
Published: December 2014

The association between depression and omega‐3 polyunsaturated fatty acids, including eicosapentaenoic and docosahexaenoic acid, continues to gain focus. In this study, we examined whether dietary intakes and plasma concentrations of eicosapentaenoic and docosahexaenoic acid were associated with depressive symptoms during pregnancy. Healthy Japanese women with singleton pregnancies were recruited at a university hospital in Tokyo between 2010 and 2012. The depressive‐symptom group included participants with Edinburgh Postnatal Depression Scale scores greater than eight. Of the 329 participants, 19 (5.8%) had depressive symptoms. Lower plasma docosahexaenoic acid concentration was significantly associated with prenatal depressive symptoms. Women with depressive symptoms had a higher rate of pregnancy‐associated nausea than those with non‐depressive symptoms (52.6% vs 28.7%, respectively). Although we adjusted for the presence of pregnancy‐associated nausea, dietary fatty acid intake was not associated with depressive symptoms in the multiple logistic regression analyses. Further large studies would be required to examine any preventive effect of dietary fatty acid intake on depressive symptoms among pregnant women.
Molecular mechanisms for mediating light‐dependent nucleo/cytoplasmic partitioning of phytochrome photoreceptors
Authors: Klose Cornelia , Viczián András , Kircher Stefan , Schäfer Eberhard , Nagy Ferenc
Published: December 2014

The photoreceptors phytochromes monitor the red/far‐red part of the spectrum, exist in the biologically active Pfr (far‐red absorbing) or inactive Pr (red absorbing) forms, and function as red/far‐red light‐regulated molecular switches to modulate plant development and growth. Phytochromes are synthesized in the cytoplasm, and light induces translocation of the Pfr conformer into the nucleus. Nuclear import of phytochromes is a highly regulated process and is fine‐tuned by the quality and quantity of light. It appears that phytochrome A (phyA) and phytochrome B (phyB) do not possess active endogenous nuclear import signals (NLSs), thus light‐induced translocation of these photoreceptors into the nucleus requires direct protein–protein interactions with their NLS‐containing signaling partners. Sub‐cellular partitioning of the various phytochrome species is mediated by different molecular machineries. Translocation of phyA into the nucleus is promoted by FAR‐RED ELONGATED HYPOCOTYL 1 (FHY1) and FHY1‐LIKE (FHL), but the identity of nuclear transport facilitators mediating the import of phyB‐E into the nucleus remains elusive. Phytochromes localized in the nucleus are associated with specific protein complexes, termed photobodies. The size and distribution of these structures are regulated by the intensity and duration of irradiation, and circumstantial evidence indicates that they are involved in fine‐tuning phytochrome signaling.
The evolution of halophytes, glycophytes and crops, and its implications for food security under saline conditions
Authors: Cheeseman John M.
Published: December 2014

The effective development of salt tolerant crops requires an understanding that the evolution of halophytes, glycophytes and our major grain crops has involved significantly different processes. Halophytes (and other edaphic endemics) generally arose through colonization of habitats in severe disequilibrium by pre‐adapted individuals, rather than by gradual adaptation from populations of ‘glycophytes’. Glycophytes, by contrast, occur in low sodium ecosystems, where sodium was and is the major limiting nutrient in herbivore diets, suggesting that their evolution reflects the fact that low sodium individuals experienced lower herbivory and had higher fitness. For domestication/evolution of crop plants, the selective pressure was human imposed and involved humans co‐opting functions of defense and reproductive security. Unintended consequences of this included loss of tolerance to various stresses and loss of the genetic variability needed to correct that. Understanding, combining and manipulating all three modes of evolution are now critical to the development of salt tolerant crops, particularly those that will offer food security in countries with few economic resources and limited infrastructure. Such efforts will require exploiting the genetic structures of recently evolved halophytes, the genetic variability of model plants, and endemic halophytes and ‘minor’ crops that already exist.

Contents

Summary
557

I.
Introduction
557

II.
On the evolution of halophytes
558

III.
Glycophytes – the other salt problem
561

IV.
Crops – adaptation with loss of critical functions
565

V.
Moving forward
565

VI.
Concluding remarks
566

Acknowledgements
567

References
567
Epistemic Value and the New Evil Demon
Authors: Madison B. J. C.
Published: December 2014

In this article I argue that the value of epistemic justification cannot be adequately explained as being instrumental to truth. I intend to show that false belief, which is no means to truth, can nevertheless still be of epistemic value. This in turn will make a good prima facie case that justification is valuable for its own sake. If this is right, we will have also found reason to think that truth value monism is false: assuming that true belief does have value, there is more of final epistemic value than mere true belief.
Xanthoma Disseminatum Associated with Inflammatory Arthritis and Synovitis—A Rare Association
Authors: Gupta Prashant , Khandpur Sujay , Vedi Kamal , Singh Manoj K. , Walia Ritika
Published: December 2014

Xanthoma disseminatum (XD) is a rare, benign, non‐Langerhans cell histiocytosis characterized by disseminated xanthomatous lesions with a predilection for the face, flexures, and mucosae. Approximately 100 cases have been reported in the literature. We report XD in an 8‐year‐old boy with symmetric synovitis and arthritis involving the wrists and knees. This case is interesting in view of the association between arthritis and synovitis and XD, which to our knowledge has not been reported in the literature. This case has to be differentiated from multicentric histiocytosis, another non‐Langerhans cell histiocytosis, in which joint involvement is common.
Resistance sources to Fusarium oxysporum f. sp. cubense tropical race 4 in banana wild relatives
Authors: Li W. M. , Dita M. , Wu W. , Hu G. B. , Xie J. H. , Ge X. J.
Published: December 2014

Target trait evaluation in crop wild relatives is an important prerequisite for efficiently using the potential useful genes located in this valuable germplasm. Over recent decades, Fusarium oxysporum f. sp. cubense tropical race 4 (Foc‐TR4) has seriously threatened worldwide banana plantations. Breeding new resistant cultivars from wild banana species is expected to provide invaluable additional resources. However, knowledge on resistance to Foc‐TR4 in wild Musa species is very limited. In this study, eight genotypes of wild banana relatives (Musa acuminata subsp. burmannica, M. balbisiana, M. basjoo, M. itinerans, M. nagensium, M. ruiliensis, M. velutina and M. yunnanensis) were characterized for resistance to Foc‐TR4 in both greenhouse and field conditions. Most wild bananas showed higher resistance levels to Foc‐TR4 than the reference cultivars ‘Brazilian’ (AAA, susceptible) and ‘Goldfinger’ (AAAB, moderate resistance). Among the wild species, M. balbisiana showed the highest levels of disease intensity followed by M. acuminata subsp. burmannica. Some individuals of M. yunnanensis, M. nagensium, M. ruiliensis and M. velutina showed low levels of rhizome discolouration in greenhouse conditions, but were resistant in the field. No symptoms were observed on M. basjoo and M. itinerans, suggesting higher levels of resistance to Foc‐TR4. The results revealed different sources of resistance to Foc‐TR4 in banana wild relatives, which constitute a valuable genetic resource for banana breeding programmes aiming to produce cultivars resistant to fusarium wilt.
Drifting: towards mobilities at sea
Authors: Peters Kimberley
Published: December 2014

This paper advocates a critical analysis of drifting as a particular typology of mobility. Drifting is a commonplace term used across the social sciences and particularly within physical, urban and psycho‐geographic strands of geography. However, drifting has not been unpacked within a mobilities framework as a specific trope of moving, nor has it been taken ‘to sea’ by social scientists. This is surprising given the long‐standing relationship between drift, drifting and the ocean. Recent years have witnessed a ‘filling out’ and ‘deepening’ of mobilities studies in geography and the broader social sciences, wherein mobility is not taken as singular and undifferentiated, but rather can be broken down into more specific parts that constitute particular technologies, experiences, forms and conditions of moving. This study dissects drifting by investigating the intricacies of this mobile quality and the quality of mobility. In particular, the paper draws on drifting in the context of the sea in order to demonstrate the new knowledges made possible by moving examinations from city spaces (where drifting has been most readily employed as conceptual tool and method). Indeed, drawing on case studies of drifting at sea, this paper argues that a focus on this distinctive form of mobility generates new insights into the politics of what it means to move in the maritime realm, a space often neglected in studies of mobilities.
A study of seroprevalence and rates of asymptomatic viremia of severe fever with thrombocytopenia syndrome virus among Chinese blood donors
Authors: Zeng Peibin , Ma Lili , Gao Zhan , Wang Jingxing , Liu Jing , Huang Xianwei , Yang Qizhi , Cao Ruan , Wen Xiuqiong , Zhu Lili , Ma Hongli , Yang Zhendong , Lee Tzong‐Hae , Brambilla Donald , Yuan Michelle , Glynn Simone , Ness Paul , Kleinman Steve , Busch Michael , Shan Hua ,   International Component of the NHLBI Recipient Epidemiology and Donor Evaluation Study‐III (REDS‐III)
Published: December 2014

Background

Severe fever with thrombocytopenia syndrome virus (SFTSV), an emerging tick‐borne pathogen that can cause fatal severe fever with thrombocytopenia syndrome, was first identified in China in 2009. Limited evidence suggests that SFTSV can be transmitted between humans via blood contact, raising concerns over transfusion safety. A study of donor samples from three Chinese blood centers was conducted to investigate the seroprevalence and rate of SFTSV viremia among Chinese blood donors.

Study Design and Methods

From April 16 to October 31, 2012, a total of 17,208 plasma samples were collected from donors at Xinyang (located in an SFTSV‐endemic area), Mianyang, and Luoyang Blood Centers. Assessment of anti‐SFTSV total antibody was performed on all samples using enzyme‐linked immunosorbent assay. Repeat‐reactive samples were tested for SFTSV RNA using reverse transcription (RT)–real‐time polymerase chain reaction (PCR) assay with Taqman probes. In addition, 9960 of the Xinyang samples were tested in pools of 4 by the same PCR method and each of the samples in a reactive pool was tested individually.

Results

Donor seroreactivity rates were as follows: Xinyang, 0.54% (80/14,752); Mianyang, 0.27% (3/1130); and Luoyang, 0.28% (3/1326). All seroreactive samples were negative on RT‐PCR single‐sample testing. Two RT‐PCR–reactive donor samples were identified, both with estimated viral load of less than 20 plaque‐forming units/mL. The RNA prevalence rate for SFTSV among donors in Xinyang was 0.02%.

Conclusion

This was the first multiregion study of SFTSV sero‐ and viral prevalence among Chinese blood donors. Viral prevalence was low and no seroreactive sample was viremic, suggesting a limited impact of SFTSV on blood safety in China.
CD44 antibody–mediated amelioration of murine immune thrombocytopenia (ITP): mouse background determines the effect of FcγRIIb genetic disruption
Authors: Crow Andrew R. , Amash Alaa , Lazarus Alan H.
Published: December 2014

Background

Several monoclonal antibodies to CD44 can successfully ameliorate murine immune thrombocytopenia (ITP). As these antibodies may be a potential replacement for intravenous immune globulin (IVIG) in the treatment of ITP and other autoimmune diseases, an understanding of their mechanisms of action is important. The role of the inhibitory Fc receptor (FcγRIIb) in the mechanism of action of IVIG and therapeutic CD44 antibodies remains uncertain. To assess if FcγRIIb in splenic macrophages plays a critical role in the action of these two therapeutics, splenectomized mice and mice genetically deficient in FcγRIIb on different backgrounds were evaluated.

Study Design and Methods

Thrombocytopenia was induced in FcγRIIb‐deficient mice on B6;129S, C57BL/6, and BALB/C backgrounds, as well as splenectomized mice and control mice by platelet (PLT) antibody. PLT counts were enumerated before and after treatment with anti‐CD44, red blood cell antibodies, or IVIG.

Results

Anti‐CD44 is ineffective at inhibiting thrombocytopenia in B6;129S FcγRIIb‐deficient mice but, like IVIG, is effective in splenectomized mice and FcγRIIb‐deficient mice on the BALB/C and C57BL/6 background.

Conclusion

These data suggest that 1) the B6;129S background itself is unlikely to be the sole reason for anti‐CD44's inability to function in B6;129S FcγRIIb‐deficient mice, 2) the simple loss of macrophage FcγRIIb expression alone is insufficient to explain anti‐CD44 ameliorative function, and 3) a combination of mouse background genes in addition to FcγRIIb genetic disruption may affect the ability of anti‐CD44 to function therapeutically. Similarities between IVIG and anti‐CD44 mechanisms suggest that patients responsive to IVIG may also potentially respond to anti‐CD44 treatment.
Transfusion‐related acute lung injury not a two‐hit, but a multicausal model
Authors: Middelburg Rutger A. , van der Bom Johanna G.
Published: December 2014

Background

The etiology of transfusion‐related acute lung injury (TRALI) is often referred to as a “two‐hit model,” the first hit being patient predisposition and the second being a transfusion. This model lumps all patient‐related risk factors together and thereby may hamper identification of individual, potentially preventable or modifiable risk factors.

Study design and methods

Like any disease, TRALI is multicausal in nature. To be able to effectively scrutinize all contributing causes, we need to clearly describe this multicausality as completely as possible. Several models are already commonly used to describe the multicausality of other diseases, including threshold models and the sufficient cause model.

Results

Here we describe the application of two different multicausal models to TRALI. These models can readily describe any potential scenario for the etiology of TRALI. First we will introduce the intuitively appealing threshold model, which shows some similarities with the Bux and Sachs threshold model for TRALI. Second we discuss the more abstract sufficient cause model.

Conclusions

Both models have their strengths and limitations. Both are, however, better equipped than the two‐hit model to describe the multicausal nature of TRALI. Further identification of all involved risk factors and the complex interplay between them is facilitated by these models.
Composition of lymphocyte subpopulations in normal canine lymph nodes
Authors: Rütgen Barbara C. , König Ramona , Hammer Sabine E. , Groiss Sandra , Saalmüller Armin , Schwendenwein Ilse
Published: December 2014

Background

Flow cytometric immunophenotyping of lymph node aspirates has become a standard practice of canine lymphoma diagnostic workup. Ultimately, the combination of flow cytometry data, histopathology, and clinical signs allows consensus classification, and improves prognostic accuracy and therapeutic approaches.

Objectives

Although there is a growing body of information regarding lymphocyte population subsets in various types of lymphoma, only few studies provide information regarding the composition of the normal canine lymph node. The aim of this prospective study was to establish exploratory reference data for lymphocyte subpopulations in normal canine lymph nodes using an extended panel of antibodies.

Methods

Popliteal lymph nodes excised from normal dogs were analyzed by cytology, multi‐color flow cytometry using 11 different canine‐specific and anti‐human cross‐reactive monoclonal antibodies, and polymerase chain reaction for antigen receptor rearrangement (PARR).

Results

Subpopulations from lymph nodes of 26 dogs were classified according to the following positive antibody reactions: CD11a+ 92.2 ± 12.3%, CD3+ 55.0 ± 14.1%, CD3‐12+ 57.3 ± 14%, CD5+ 52.3 ± 12.7%, CD21+ 33.9 ± 11.8%, CD79αcγ+ 46.9 ± 14.8%, CD56+ 4.9 ± 5.9%, and CD14+ 5.5 ± 6.8%. There were 58.7 ± 9% CD4+ and 21.3 ± 7.8% CD8+ cells inside the gate of CD3+ cells. Cytology revealed a mixed population of mostly lymphoid cells in all samples. The absence of a monoclonal or oligoclonal neoplastic population was confirmed by PARR.

Conclusion

This study establishes for the first time flow cytometry data of lymphocyte populations in a larger group of normal canine lymph nodes, including populations positive for some new antibodies against CD3‐12, CD5, CD11a, CD56, and CD79αcy.
Enhanced Computational Fluid Dynamics Modeling and Laser Doppler Anemometer Measurements for the Air-Flow in an Aero-engine Front Bearing Chamber—Part II
Authors: Aidarinis J. , Goulas A.
Published: December 2014

A detailed computational study of the air-flow through the outer gap of the front bearing of an aero-engine is presented. The reason to carry out this study was to understand the flow through the bearing as a function of the operational parameters of the engine, which was necessary for the modeling of the flow in the whole bearing chamber. The complex geometry and the size of the bearing gap relative to the overall dimensions of the bearing chamber and the need for very precise and detailed information of the effect on the flow within the chamber of the bearing operational parameters, prohibited the solution of the flow through the gap together with the rest of the bearing chamber. A 3D modeling of the flow through the outer bearing gap, which included a section of the ball bearing, was performed. Functions relating the pressure drop of the air coming through the bearing gap and the tangential component of velocity of the air exiting the bearing region, to the mass of air through the gap of the ball bearing and the rotational speed of the shaft were developed. The effect of the lubrication oil within the bearing was modeled as an anisotropic porous medium with a predefined law. In order to acquire in a mathematical form the above relationships a series of computational runs were performed. These relationships, in the form of second order curves, were subsequently introduced to the model of the bearing chamber as described by Aidarinis and Goulas (2014, “Enhanced CFD Modeling and LDA Measurements for the Air-Flow in an Aero Engine Front Bearing Chamber (Part I),” ASME Paper No. GT2014-26060). The constants of the relationships were derived through comparisons of the calculations with the experimental data. From the analysis, it was concluded that the pressure drop across the bearing increases with the square of the rotational speed of the shaft with the mass flow of air through the ball bearing as a parameter and vice versa. For this particular ball bearing, there is a region where, for any combination of rotational speed of the shaft and pressure drop through the bearing, there is no flow of air through the bearing. In this paper the detailed modeling methodology, the computational flow field, the boundary conditions and finally the results are presented and discussed.
Amplitude-Dependent Flow Field and Flame Response to Axial and Tangential Velocity Fluctuations
Authors: Schimek Sebastian , Ćosić Bernhard , Moeck Jonas P. , Terhaar Steffen , Oliver Paschereit Christian
Published: December 2014

The current paper investigates the nonlinear interaction of the flow field and the unsteady heat release rate and the role of swirl fluctuations. The test rig consists of a generic swirl-stabilized combustor fed with natural gas and equipped with a high-amplitude forcing device. The influence of the phase between axial and azimuthal velocity oscillations is assessed on the basis of the amplitude and phase relations between the velocity fluctuations at the inlet and the outlet of the burner. These relations are determined in the experiment with the multimicrophone-method and a two component laser Doppler velocimeter (LDV). Particle image velocimetry (PIV) and OH*-chemiluminescence measurements are conducted to study the interaction between the flow field and the flame. For several frequency regimes, characteristic properties of the forced flow field and flame are identified, and a strong amplitude dependence is observed. It is found that the convective time delay between the swirl generator and the flame has an important influence on swirl-number oscillations and the flame dynamics in the low-frequency regime. For mid and high frequencies, significant changes in the mean flow field and the mean flame position are identified for high forcing amplitudes. These affect the interaction between coherent structures and the flame and are suggested to be responsible for the saturation in the flame response at high forcing amplitudes.
Near-Field Characteristics of a Rectangular Jet and Its Effect on the Liftoff of Turbulent Methane Flame
Authors: Akbarzadeh Mohsen , Birouk Madjid
Published: December 2014

Understanding the stability of turbulent flames is a key for the design of efficient combustion systems. The present paper reports an experimental study on the effect of the internal geometry of a rectangular orifice on the characteristics/stability of a turbulent methane flame. Three rectangular nozzles with different orifice lengths having an identical exit aspect ratio (AR) of 2 were used. The co-airflow strength was also varied to evaluate its effect on the jet flow emerging from the rectangular nozzle. The experimental data revealed that the jet initial conditions affect both the flow characteristics and the liftoff of turbulent diffusion methane flame. That is, increasing the orifice length of the rectangular nozzle resulted in delaying the occurrence of the axis-switching phenomenon, reducing the length of the jet potential core, and accelerating the liftoff transition of the attached flame. The co-airflow was found to reduce the velocity strain rate in the shear layer, displace the occurrence of axis-switching farther downstream of the jet, and delay flame detachment. The results revealed also that there is a clear interplay between the flame liftoff and the jet near-field molecular mixing and flow characteristics. That is, a rectangular jet which spreads faster and generates higher near-field velocity strain and turbulence intensity causes flame detachment at a lower fuel jet velocity. Based on this, a correlation was found between the flame liftoff velocity, the fuel molecular thermal diffusivity, the stoichiometric laminar flame speed, and the fuel jet strain rate at the nozzle exit. This relationship was shown to successfully predict the liftoff velocity of methane flame as well as other common gaseous hydrocarbons and hydrogen flames.
Active Vibration Control of the Flexible Rotor in High Energy Density Magnetically Suspended Motor With Mode Separation Method
Authors: Tang Enqiong , Fang Jiancheng , Han Bangcheng
Published: December 2014

Since the mass of the rotor in high energy density magnetically suspended motor (HEDMSM) is always large and there are only three balancing planes on the flexible rotor restricted by the structure of the motor, which means that the second bending mode cannot be balanced using N + 1 planes method which is always applied to balance the flexible rotor. Then, the rotor displacements maybe large and this situation will make the system consume large amplifier currents when the rotor passes the first bending critical speed. Therefore, the mode separation method is proposed to separate the first and the second bending modes in rotor displacement and reconstruct the displacement signal nearby the first bending mode. Then, the original rotor displacement signal used by the digital controller is substituted by the reconstructed displacement signal and the amplifier current is reduced a lot when the rotor passes the first bending critical speed. Finally, the experiment of mode separation is carried out in 100 kW magnetically suspended motor and the experiment results show the effectiveness and superiority of the mode separation method in reducing the amplifier current when the rotor passes the first bending critical speed.
Sun-Relative Pointing for Dual-Axis Solar Trackers Employing Azimuth and Elevation Rotations
Authors: Riley Daniel , Hansen Clifford
Published: December 2014

We present an algorithm to calculate the azimuth and elevation angles for a dual axis tracker to be pointed away from the sun with a desired orientation between the sun and the tracker face. Desired tracker positions are specified in terms of angle of incidence (AOI) and AOI direction, i.e., the direction of the projection of the sun beam onto the plane of the tracker face. This algorithm was developed to enable characterization of the electro-optical response of photovoltaic (PV) and concentrating PV (CPV) modules with anisotropic response to AOI.
An Exact Analytical Approach for Free Vibration Analysis of Built-Up Space Frames
Authors: Mei C. , Sha H.
Published: December 2014

Coupled in- and out-of-plane bending, axial, and torsional vibrations exist in a built-up space frame, which greatly challenges the conventional modal approach. A wave-based exact analytical method is applied to study vibrations in built-up multistory space frames. From the wave vibration standpoint, vibrations are described as waves propagating along uniform structural elements and being reflected and transmitted at structural discontinuities. Free vibration responses are studied based on classical vibration theories. Numerical examples are given with comparison to results available in the literature. Good agreements have been reached. This study not only provides an exact analytical approach to complex vibration problems in built-up multistory space frames that have mostly been studied numerically but also provides a benchmark to existing numerical tools.
Simulation of Energy Production in Grid-Connected Photovoltaic Systems From Measured and Calculated Data From Clear-Sky Radiation Model
Authors: Henrique Rossa Carlos , Batista Dias João , Henrique Macagnan Mário
Published: December 2014

This paper presents a comparison of the energy production in grid-connected photovoltaic systems (GCPPS) from measured and calculated radiation data. The Linke turbidity (TL) factor for the region of Porto Alegre, Brazil, was extracted considering the data of direct solar radiation from the typical meteorological year (TMY). The average annual turbidity value obtained of 4.03 agrees with the wet climate of the region which presents only 17.26% of clear-sky days. There was a difference of 27.5% in the results of the produced energy, which drops to 6.5% when compared with only sunny days in the region, suggesting that the model in the current configuration for this type of estimate is barely adequate.
Strength Analysis of Syntactic Foams Using a Three-Dimensional Continuum Damage Finite Element Model
Authors: Shan Yejie , Nian Guodong , Xu Qiang , Tao Weiming , Qu Shaoxing
Published: December 2014

The failure behavior of the syntactic foams is investigated based on a three-dimensional (3D) micromechanical finite element (FE) model, by varying the volume fraction, the wall thickness of the hollow particles, and the interfacial strength. The maximum principal stress criterion is adopted to determine the state (damaged or undamaged) for both interface and matrix. Material property degradation is used to describe the mechanical behavior of those damaged elements. The current model can reasonably predict the tensile strength of the syntactic foams with high volume fractions (40%–60%). The failure mechanism of the syntactic foam under uniaxial tension is captured by analyzing the stress–strain curves and the contours of damaging evolution process. Results from the quantitative simulations demonstrate that the tensile strength of the syntactic foam can be improved effectively by enhancing the interfacial strength.
A Three-Dimensional Quantitative Structure Tribo-Ability Relationship Model
Authors: Gao Xinlei , Wang Zhan , Zhang Hong , Dai Kang
Published: December 2014

The prediction of lubrication characteristics for compounds through tribological models would aid in the discovery of new lubricant additives and improved lubricant design. But until recently, the field of tribological prediction has been sparse and not systematic. Tribological processes are complex and involve molecular energy exchange as well as conformation transitions. We have developed a platform of a “quantitative structure tribo-ability relationship (QSTR),” which enables us to introduce well-developed quantitative structure–activity relationships (QSAR) methods into tribology systematically. The present study applies “evaluation of infrared vibration-based” (EVA) descriptors, which are three-dimensional (3D) QSAR descriptors to simulate infrared (IR) vibration properties of molecules, in order to establish the QSTR prediction model. As structural changes take place under friction loads, the EVA descriptors characterize both molecular energy and conformations. The results show a strong correlation and robust predictability of the EVA model to tribological parameters. The approach paves a way to a systematic QSTR.
Microscopic silicon-based lateral high-aspect-ratio structures for thin film conformality analysis
Authors: Gao Feng , Arpiainen Sanna , Puurunen Riikka L.
Published: December 2014

Film conformality is one of the major drivers for the interest in atomic layer deposition (ALD) processes. This work presents new silicon-based microscopic lateral high-aspect-ratio (LHAR) test structures for the analysis of the conformality of thin films deposited by ALD and by other chemical vapor deposition means. The microscopic LHAR structures consist of a lateral cavity inside silicon with a roof supported by pillars. The cavity length (e.g., 20–5000 μm) and cavity height (e.g., 200–1000 nm) can be varied, giving aspect ratios of, e.g., 20:1 to 25 000:1. Film conformality can be analyzed with the microscopic LHAR by several means, as demonstrated for the ALD Al2O3 and TiO2 processes from Me3Al/H2O and TiCl4/H2O. The microscopic LHAR test structures introduced in this work expose a new parameter space for thin film conformality investigations expected to prove useful in the development, tuning and modeling of ALD and other chemical vapor deposition processes.
Thermodynamics and kinetic behaviors of thickness-dependent crystallization in high-k thin films deposited by atomic layer deposition
Authors: Nie Xianglong , Ma Fei , Ma Dayan , Xu Kewei
Published: December 2014

Atomic layer deposition is adopted to prepare HfO2 and Al2O3 high-k thin films. The HfO2 thin films are amorphous at the initial growth stage, but become crystallized when the film thickness (h) exceeds a critical value (hcritical*). This phase transition from amorphous to crystalline is enhanced at higher temperatures and is discussed, taking into account the effect of kinetic energy. At lower temperatures, the amorphous state can be maintained even when h>hcritical* owing to the small number of activated atoms. However, the number of activated atoms increases with the temperature, allowing crystallization to occur even in films with smaller thickness. The Al2O3 thin films, on the other hand, maintain their amorphous state independent of the film thickness and temperature owing to the limited number of activated atoms. A thermodynamic model is proposed to describe the thickness-dependent phase transition.
Undoped TiO2 and nitrogen-doped TiO2 thin films deposited by atomic layer deposition on planar and architectured surfaces for photovoltaic applications
Authors: Tian Liang , Soum-Glaude Audrey , Volpi Fabien , Salvo Luc , Berthomé Grégory , Coindeau Stéphane , Mantoux Arnaud , Boichot Raphaël , Lay Sabine , Brizé Virginie , Blanquet Elisabeth , Giusti Gaël , Bellet Daniel
Published: December 2014

Undoped and nitrogen doped TiO2 thin films were deposited by atomic layer deposition on planar substrates. Deposition on 3D-architecture substrates made of metallic foams was also investigated to propose architectured photovoltaic stack fabrication. All the films were deposited at 265 °C and nitrogen incorporation was achieved by using titanium isopropoxide, NH3 and/or N2O as precursors. The maximum nitrogen incorporation level obtained in this study was 2.9 at. %, resulting in films exhibiting a resistivity of 115 Ω cm (+/−10 Ω cm) combined with an average total transmittance of 60% in the 400–1000 nm wavelength range. Eventually, TiO2 thin films were deposited on the 3D metallic foam template.
Applicability of the extended Derjaguin–Landau–Verwey–Overbeek theory on the adsorption of bovine serum albumin on solid surfaces
Authors: Wang Hua , Newby Bi-min Zhang
Published: December 2014

Protein adsorption is the prerequisite for bacterial attachment and cellular adhesion, which are critical for many biomedical applications. To understand protein adsorption onto substrates, predictive models are generally informative prior to experimental studies. In this study, the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory was employed to determine whether or not it could interpret the protein adsorption behaviors. The experimental results of fluorescein isothiocyanate labeled bovine serum albumin (BSA) adsorbed on six different surfaces: glass, octadecyltrichlorosilane modified glass, 2-[methoxypoly(ethyleneoxy)propyl]trimethoxy-silane (PEG)-modified glass, polystyrene, poly(dimethylsiloxane), and poly(methyl methacrylate) were utilized. The XDLVO interaction energy curves, especially from the contribution of acid–base interactions, obtained using the surface properties of substrates and BSA molecules qualitatively predict/interpret the protein adsorption behaviors on these surfaces. Some derivation of the experimental results from the prediction was noticed for the glass and the PEG-modified glass. When including a hydration layer to the PEG-modified glass surface, the nonfouling result of such surface by proteins was also elucidated by the XDLVO theory.
Priority setting partnership to identify the top 10 research priorities for the management of Parkinson's disease
Authors: Deane Katherine H O , Flaherty Helen , Daley David J , Pascoe Roland , Penhale Bridget , Clarke Carl E , Sackley Catherine , Storey Stacey
Published: December 2014

Objectives

This priority setting partnership was commissioned by Parkinson's UK to encourage people with direct and personal experience of the condition to work together to identify and prioritise the top 10 evidential uncertainties that impact on everyday clinical practice for the management of Parkinson's disease (PD).

Setting

The UK.

Participants

Anyone with experience of PD including: people with Parkinson's (PwP), carers, family and friends, healthcare and social care professionals. Non-clinical researchers and employees of pharmaceutical or medical devices companies were excluded. 1000 participants (60% PwP) provided ideas on research uncertainties, 475 (72% PwP) initially prioritised them and 27 (37% PwP) stakeholders agreed a final top 10.

Methods

Using a modified nominal group technique, participants were surveyed to identify what issues for the management of PD needed research. Unique research questions unanswered by current evidence were identified and participants were asked to identify their top 10 research priorities from this list. The top 26 uncertainties were presented to a consensus meeting with key stakeholders to agree the top 10 research priorities.

Results

1000 participants provided 4100 responses, which contained 94 unique unanswered research questions that were initially prioritised by 475 participants. A consensus meeting with 27 stakeholders agreed the top 10 research priorities. The overarching research aspiration was an effective cure for PD. The top 10 research priorities for PD management included the need to address motor symptoms (balance and falls, and fine motor control), non-motor symptoms (sleep and urinary dysfunction), mental health issues (stress and anxiety, dementia and mild cognitive impairments), side effects of medications (dyskinesia) and the need to develop interventions specific to the phenotypes of PD and better monitoring methods.

Conclusions

These research priorities identify crucial gaps in the existing evidence to address everyday practicalities in the management of the complexities of PD.
The association between intradialytic exercise and hospital usage among hemodialysis patients
Authors: Parker Kristen , Zhang Xin , Lewin Adriane , MacRae Jennifer M.
Published: December 2014

Hemodialysis (HD) patients have high hospitalization rates. Benefits of intradialytic exercise have been proven in numerous studies yet exercise programs are still rarely used in the treatment of end-stage kidney disease (ESKD). Our objective was to determine if there was an association between a 6-month intradialytic bicycling program and hospitalization rates and length of stay (LOS) in ESKD patients. This was a retrospective cohort study that took place 6 months prior to and 6 months during an intradialtyic exercise program at an outpatient HD unit in Calgary, Alberta, Canada. Participants comprised 102 patients who had commenced HD <6 months (incident) or >6 months (prevalent) prior to starting exercise. The intervention comprised a 6-month intradialytic bicycling program. Main outcome measures were hospitalization rate, cause of hospitalization, and LOS. Patients were predominantly male (67.6%) aged 65.6 ± 13.5 years and median HD vintage 1 year (range: 0–12). Comorbidities included diabetes mellitus (50%) and cardiac disease (38.2%). The hospitalization incidence rate ratio (IRR) was 0.48 (0.23–0.98; P = 0.04) in incident and 0.89 (0.56–1.42; P = 0.64) in prevalent patients. The LOS decreased from 7.8 (95% confidence interval (CI): 7.3–8.4) to 3.1 (95% CI: 2.8–3.4) days and LOS IRR was 0.39 (0.35–0.45; P < 0.001). The main predictors of hospitalization were lower albumin levels (P = 0.007) and lack of intradialytic exercise program participation (P < 0.001). In conclusion, 6 months of intradialytic exercise was associated with decreased LOS in both incident and prevalent HD patients.