bluuebunny/crossref_metadata_2025 huggingface dataset:
Downregulation of the Endothelial Genes Notch1 and EphrinB2 in Patients with Nodular Regenerative Hyperplasia
Authors: Rothweiler Sonja , Terracciano Luigi , Tornillo Luigi , Dill Michael T. , Heim Markus H. , Semela David
Published: June 2013

Background & Aims

Nodular regenerative hyperplasia (NRH) is a rare liver disease characterized by small regenerative nodules without fibrosis and can cause portal hypertension. Aetiology and pathogenesis of NRH remain unclear. We have recently shown that Notch1 knockout induces NRH with portal hypertension through vascular remodelling in mice. The aim of this study was to analyse histological and clinical data of NRH patients and to explore if the endothelial pathways identified in our NRH mouse model are also regulated in human NRH.

Methods

Patients were identified retrospectively from the pathology database. Clinical and laboratory patient data were retrieved. mRNA expression was measured in liver biopsies from a subset of NRH patients.

Results

Diagnosis of NRH was confirmed in needle biopsies of 51 patients, including 31 patients with grade 1, 12 patients with grade 2 and 8 patients with grade 3 NRH. Grade 3 nodularity significantly correlated with the presence of portal hypertension: 50% of the patients with grade 3 NRH vs. 6.5% with grade 1 (P = 0.0105). mRNA expression analysis in liver biopsies from 14 NRH patients and in primary human sinusoidal endothelial cells revealed downregulation of identical genes as in the murine NRH model, which are implicated in vascular differentiation: Notch1, delta‐like 4 (Dll4) and ephrinB2.

Conclusions

In this large NRH needle biopsy cohort, we demonstrated that advanced nodularity correlates with presence of portal hypertension. Downregulation of the endothelial signalling pathways Dll4/Notch1 and ephrinB2/EphB4 supports the hypothesis that human NRH is caused by a sinusoidal injury providing first insights into the molecular pathogenesis of this liver condition.
Single‐molecule atomic force microscopy unravels the binding mechanism of a Burkholderia cenocepacia trimeric autotransporter adhesin
Authors: El‐Kirat‐Chatel Sofiane , Mil‐Homens Dalila , Beaussart Audrey , Fialho Arsenio M. , Dufrêne Yves F.
Published: June 2013

Trimeric autotransporter adhesins (TAAs) are bacterial surface proteins that fulfil important functions in pathogenic Gram‐negative bacteria. Prominent examples of TAAs are found in Burkholderia cepacia complex, a group of bacterial species causing severe infections in patients with cystic fibrosis. While there is strong evidence that Burkholderia cenocepacia TAAs mediate adhesion, aggregation and colonization of the respiratory epithelium, we still know very little about the molecular mechanisms behind these interactions. Here, we use single‐molecule atomic force microscopy to unravel the binding mechanism of BCAM0224, a prototype TAA from B. cenocepacia K56‐2. We show that the adhesin forms homophilic trans‐interactions engaged in bacterial aggregation, and that it behaves as a spring capable to withstand high forces. We also find that BCAM0224 binds collagen, a major extracellular component of host epithelia. Both homophilic and heterophilic interactions display low binding affinity, which could be important for epithelium colonization. We then demonstrate that BCAM0224 recognizes receptors on living pneumocytes, and leads to the formation of membrane tethers that may play a role in promoting adhesion. Collectively, our results show that BCAM0224 is a multifunctional adhesin endowed with remarkable binding properties, which may represent a general mechanism among TAAs for strengthening bacterial adhesion.
Treatment cost development of patients undergoing remission induction chemotherapy: a pharmacoeconomic analysis before and after introduction of posaconazole prophylaxis
Authors: Heimann Sebastian M. , Cornely Oliver A. , Vehreschild Maria J. G .T. , Glossmann Jan , Kochanek Matthias , Kreuzer Karl‐Anton , Hallek Michael , Vehreschild Jörg J.
Published: June 2013

Prior clinical trials have demonstrated efficacy and effectiveness of posaconazole in the prophylaxis of invasive fungal diseases in high‐risk patients. Controversy exists about the cost‐effectiveness of this approach. We performed an analysis comparing the direct costs of posaconazole prophylaxis against polyene mouthwash (thrush) prophylaxis in patients with acute myelogenous leukaemia (AML). Data of AML patients receiving remission‐induction chemotherapy were extracted from the CoCoNut (Cologne Cohort of Neutropenic Patients) database to compare hospital costs of patients before (2003–2005) and after (2006–2008) introduction of posaconazole prophylaxis. Treatment on general ward, intensive care unit (ICU), mechanical ventilation, diagnostic procedures, and all anti‐infectives were calculated. Patient groups were well matched according to age, gender and duration of neutropenia. The mean costs per patient in the posaconazole group (n = 76) and the polyene mouthwash group (n = 81) were €21 040 (95% confidence interval (CI): €18 204–€23 876) and €23 169 (95% CI: €19 402–€26 937) per patient. Antifungal treatment costs were €4580 (95% CI: €3678–€5482) and €4019 (95% CI: €2825–€5214). Duration on the ICU was 2582 (95% CI: 984.1–4181.7) and 5517 (95% CI: 2206–8827.3) min. In our hospital, primary antifungal prophylaxis by posaconazole was cost‐effective. There was a trend towards cost savings, which was primarily caused by a shorter overall length of stay and the less frequent ICU treatment.
A simple novel technique to induce short‐lasting local brain ischaemia in the rat
Authors: Knapp Levente , Gellért Levente , Herédi Judit , Kocsis Kitti , Oláh Gáspár , Fuzik János , Kis Zsolt , Vécsei László , Toldi József , Farkas Tamás
Published: June 2013

Aims

Brain ischaemia models are essential to study the pathomechanisms of stroke. Our aim was to investigate the reliability and reproducibility of our novel focal ischaemia‐reperfusion model.

Methods

To induce a cortical transient ischaemic attack, we lifted the distal middle cerebral artery (MCA) with a special hook. The early changes after 2 × 15‐min occlusion were observed in the somatosensory evoked responses (SERs). The histological responses to 2 × 15‐min MCA occlusion and to 30‐, 45‐ or 60‐min ischaemia were examined after a 1‐day survival period by 2,3,5‐triphenyltetrazolium chloride (TTC) and Fluoro Jade C (FJC) staining. Another group, with 30‐min ischaemia, was analysed histologically by FJC, S100 and CD11b labelling after a 5‐day survival period.

Results

The amplitudes of the SERs decreased immediately at the beginning of the ischaemic period, and remained at a reduced level during the ischaemia. Reperfusion resulted in increasing SER amplitudes, but they never regained the control level. The short‐lasting ischaemia did not lead to brain infarction when evaluated with TTC, but intense labelling was found with FJC. The 30‐min ischaemia did not result in FJC labelling after 1 day, but marked labelling was observed after 5 days with FJC, S100 and CD11b in the cortical area supplied by the MCA.

Conclusions

We present here a novel, readily reproducible method to induce focal brain ischaemia. The ischaemia‐reperfusion results in noteworthy changes in the SERs and the appearance of conventional tissue damage markers. This method involves possibilities for precise blood flow regulation, and the setting of the required level of perfusion.
Contribution of subgenomes to the transcriptome and their intertwined regulation in the allopolyploid Coffea arabica grown at contrasted temperatures
Authors: Combes Marie‐Christine , Dereeper Alexis , Severac Dany , Bertrand Benoît , Lashermes Philippe
Published: June 2013

Polyploidy has occurred throughout the evolutionary history of plants and led to diversification and plant ecological adaptation. Functional plasticity of duplicate genes is believed to play a major role in the environmental adaptation of polyploids. In this context, we characterized genome‐wide homoeologous gene expression in Coffea arabica, a recent allopolyploid combining two subgenomes that derive from two closely related diploid species, and investigated its variation in response to changing environment.

The transcriptome of leaves of C. arabica cultivated at different growing temperatures suitable for one or the other parental species was examined using RNA‐sequencing. The relative contribution of homoeologs to gene expression was estimated for 9959 and 10 628 genes in warm and cold conditions, respectively.

Whatever the growing conditions, 65% of the genes showed equivalent levels of homoeologous gene expression. In 92% of the genes, relative homoeologous gene expression varied < 10% between growing temperatures.

The subgenome contributions to the transcriptome appeared to be only marginally altered by the different conditions (involving intertwined regulations of homeologs) suggesting that C. arabica's ability to tolerate a broader range of growing temperatures than its diploid parents does not result from differential use of homoeologs.
Get real: putting models of climate change and species interactions in practice
Authors: Buckley Lauren B.
Published: June 2013

Forecasts of the ecological impacts of climate change are generally focused on direct impacts to individual species. Theory and case studies suggest that indirect effects associated with species interactions may alter these direct responses. How can we tractably predict in which cases indirect effects are likely to be important and appropriately model the interaction of abiotic and biotic drivers? One viable strategy is to characterize partitioning between species along thermal, temporal, and spatial niche axes. The partitioning can be informed by assessing functional traits. Mechanistic models can then be applied to predict how climate change will alter niche partitioning. I illustrate this approach by asking whether competition has altered the responses of CaribbeanAnolislizards to recent warming and find that forested habitat has become more suitable for a warm‐adapted, open species, and less suitable for a cool‐adapted forest inhabitant. Competition may result in competitive displacement of the cool‐adapted species as the warm‐adapted species moves into the forest. Species interactions may accentuate abundance and distribution shifts predicted in response to climate change along the elevation gradient.
Understanding the experience of inpatient rehabilitation: insights into patient‐centred care from patients and family members
Authors: Gill Stephen D. , Dunning Trisha , McKinnon Fiona , Cook Desma , Bourke Jo
Published: June 2013

The aim of the study was describe the experiences, needs and preferences of recent inpatients of a rehabilitation centre, and the needs of their families. Data were collected in four focus groups, two with patients (n = 13) who had recently completed inpatient rehabilitation following an illness, injury or elective surgery, and two with family members (n = 11). During the focus groups, two researchers facilitated discussion on any topic that participants considered important to the experience of inpatient rehabilitation; participants were encouraged to describe their care, needs and preferences. The focus group discussions were audio‐taped and transcribed verbatim. Field notes were hand recorded. Data were analysed and collated into themes. Six key themes emerged. Participants wanted: interactions with friendly, empathetic staff; regular contact with senior staff and all staff to introduce themselves by name and profession; timely communication of accurate information; and rehabilitation services seven days a week. The physical environment had both positive and negative effects on patient well‐being. Patients with complex or atypical circumstances required special attention to ensure their needs were met. In conclusion, patients and families identified six important issues that need to be considered during inpatient rehabilitation.
Differential Expression of CD30 on CD3 T Lymphocytes in Patients with Systemic Lupus Erythematosus
Authors: Cabrera C. M. , Urra J. M. , Carreño A. , Zamorano J.
Published: June 2013

Systemic lupus erythematosus (SLE) is an autoimmune systemic disease caused as a result of an imbalance of Th1‐/Th2‐type cytokines. The soluble form of CD30 (CD30s) released from peripheral blood cells has been described as a marker of active disease in Th2‐type immune response as in SLE. However, the expression of CD30 on CD3 T lymphocytes from patients with SLE has not been studied yet. Therefore, we have addressed our study to attempt this issue, studying CD30 expression by flow cytometry on CD3 T lymphocytes and CD4/CD8 subsets in samples from SLE patients mainly with lupus nephritis. In parallel, we have determined the production of the cytokines IL‐4 (Th2), IFNγ (Th1), IL‐10 and TGFβ by intracellular staining. Differences between positive CD30 T cells in healthy controls and patients with SLE were found, with a higher percentage of CD30‐expressing T cells in patients with SLE (P = 0.001). In contrast to healthy controls, CD30 was mainly expressed on CD8 T cells from patients with SLE. The intracellular cytokine staining showed that TGFβ is the main cytokine expressed in CD3 T cells from patients with SLE. In addition to this, we have found a positive correlation between CD30‐expressing T cells and IL‐4, IFNγ, and immunosuppressive cytokines (IL‐10 and TGFβ) (P < 0.05). These results suggest that CD30 could play a role in the pathogenesis of SLE and its expression on CD3 T lymphocytes is not restricted only to Th2‐type response.
Identification and characterization of functional centromeres of the common bean
Authors: Iwata Aiko , Tek Ahmet L. , Richard Manon M.S. , Abernathy Brian , Fonsêca Artur , Schmutz Jeremy , Chen Nicolas W.G. , Thareau Vincent , Magdelenat Ghislaine , Li Yupeng , Murata Minoru , Pedrosa‐Harand Andrea , Geffroy Valérie , Nagaki Kiyotaka , Jackson Scott A.
Published: June 2013

In higher eukaryotes, centromeres are typically composed of megabase‐sized arrays of satellite repeats that evolve rapidly and homogenize within a species' genome. Despite the importance of centromeres, our knowledge is limited to a few model species. We conducted a comprehensive analysis of common bean (Phaseolus vulgaris) centromeric satellite DNA using genomic data, fluorescence in situ hybridization (FISH), immunofluorescence and chromatin immunoprecipitation (ChIP). Two unrelated centromere‐specific satellite repeats, CentPv1 and CentPv2, and the common bean centromere‐specific histone H3 (PvCENH3) were identified. FISH showed that CentPv1 and CentPv2 are predominantly located at subsets of eight and three centromeres, respectively. Immunofluorescence‐ and ChIP‐based assays demonstrated the functional significance of CentPv1 and CentPv2 at centromeres. Genomic analysis revealed several interesting features of CentPv1 and CentPv2: (i) CentPv1 is organized into an higher‐order repeat structure, named Nazca, of 528 bp, whereas CentPv2 is composed of tandemly organized monomers; (ii) CentPv1 and CentPv2 have undergone chromosome‐specific homogenization; and (iii) CentPv1 and CentPv2 are not likely to be commingled in the genome. These findings suggest that two distinct sets of centromere sequences have evolved independently within the common bean genome, and provide insight into centromere satellite evolution.
von Willebrand factor, clotting factors, and clotting inhibitors in apheresis platelet concentrates
Authors: Weiss Dominik R. , Franke D. , Strasser Erwin F. , Ringwald Juergen , Zimmermann Robert , Eckstein Reinhold
Published: June 2013

Background

Apheresis platelet concentrates (APCs) are usually stored in citrated plasma at 22°C. The stability of coagulation proteins—von Willebrand factor (vWF), clotting factors (CFs), and their inhibitors—has often been described in association with the storage of thawed plasma. However, fewer data are available regarding changes in APCs.

Study Design and Methods

We measured CF activities and inhibitors in APCs on the day of manufacture (Day 0) and on Days 4, 5, and 7. vWF was determined by measuring vWF antigen (vWF:Ag) and vWF ristocetin cofactor (vWF:RCo) and by multimer analysis.

Results

Twenty‐one PCs obtained by plateletpheresis were studied. Major changes were observed for Factor (F)VIII (37% loss of activity within 4 days), FV (20% within 4 days), and protein S (76% within 4 days). All other CF activities remained higher than 80% over the 7 days. Fibrinogen and the inhibitors antithrombin and protein C remained quite stable. FXI, FXII, and FXIII actually increased during storage (8, 11, and 12% within 4 days). vWF:Ag increased during storage of APCs by 2% per day, with a relative loss of vWF:RCo and high‐molecular‐weight multimers.

Conclusion

Even after 7 days of storage at 22°C, the hemostatic potential of the plasma content in APCs was roughly preserved. The increase in FXII antigen indicates that this CF may also be stored in platelets; however, this has not yet been described.
A new system for quality control in hematopoietic progenitor cell units before reinfusion in autologous transplant
Authors: Scerpa Maria Cristina , Rossi Cecilia , Daniele Nicola , Lanti Alessandro , Adorno Gaspare , Picardi Alessandra , Arcese William , Amadori Sergio , Isacchi Giancarlo , Zinno Francesco
Published: June 2013

Background

In our Center, the cell viability, the integrity of the bag, and the clonogenic assay were evaluated before the reinfusion of hematopoietic progenitor cells–apheresis (HPC‐A). This quality control (QC) should be made 14 days before the reinfusion to the patient to have the result of the functional test on the proliferative capacity of hematopoietic progenitors.

Study Design and Methods

This study was designed to assess the potential of an automatic cell counting system (NucleoCounter NC‐3000, ChemoMetec) in our clinical routine as a support of the clonogenic assay and the cytofluorimetric analysis for the QC of the cryopreserved HPC‐A. The cell viability was evaluated by flow cytometry using the modified International Society of Hematotherapy and Graft Engineering protocol. The proliferative potential was assessed by specific clonogenic tests using a commercial medium. Furthermore, we evaluated the cellular functionality with NucleoCounter NC‐3000, by using two protocols: “vitality assay” and “mitochondrial potential assay.”

Results

The evaluation of the total nucleated cells in preapoptosis measured by 5,5,6,6‐tetrachloro‐1,1,3,3‐tetraethylbenzimidazol‐carbocyanine iodide (JC‐1) assay showed a negative correlation (r = −0.43) with the total number of colonies (colony‐forming unit [CFU]–granulocyte‐macrophage progenitors plus burst‐forming unit–erythroid progenitors plus CFU–granulocyte, erythroid, macrophage, megakaryocyte progenitors) obtained after seeding of 50 × 106/L viable total nucleated cells. We observed a significant difference (p < 0.0001) comparing the median number of colonies (166.70; SD, ±136.36) obtained with a value of JC‐1 less than 30% to the number of colonies (61.75; SD, ±59.76) obtained with a value of JC‐1 more than 30%.

Conclusion

The evaluation of cell functionality by the use of the NucleoCounter NC‐3000 is in agreement with results from clonogenic assay and can be considered an effective alternative in the routine laboratory.
The Effects of Globalisation on the US Labour Mark'et: Service Sectors Considered
Authors: Feng Ling , Hu Weijun , Li Zhiyuan
Published: June 2013

How has globalisation affected employment and wages in the United States? Existing studies largely ignore the intersector labour movement between the manufacturing and service sectors by focusing only on the intrasector movement within the manufacturing sector. However, by decomposing the aggregate labour demand in the United States, we find that the intersector movement is more substantial than intrasector movement. Motivated by the decomposition results, this study presents a three‐sector model that includes a manufacturing sector and two service sectors at varying skill intensities. The model shows that offshoring might translate into smaller‐than‐expected wage changes because of the intersector labour movement. In line with the theoretical predictions, two notable empirical results are presented. First, an occupation's exposure to offshoring has non‐significant, albeit negative, effects on wages. Second, the more an occupation is exposed to offshoring, the lower its employment in the manufacturing sector as a share of its total employment. Furthermore, these effects are larger for more routine occupations or those requiring less education.
Commodity Price, Carry Trade, and the Volatility and Liquidity of Asian Currencies
Authors: Gochoco‐Bautista Maria Socorro , Wang Jianxin , Yang Minxian
Published: June 2013

This study examines how the volatility and liquidity of 10 Asian exchange rates against the US dollar change with volatilities in commodity price and carry trade over the period of January 2000 to June 2010. We find that uncertainties in commodity markets and carry trades are significantly correlated with the volatilities and the bid‐ask spreads of most Asian currencies. The correlation with carry trade is generally stronger and has been rising over the sample period. While high volatilities in carry trade are associated with high volatilities in many Asian currencies, high volatilities in commodity price do not coincide with excessive volatilities in Asian currencies. This suggests that investors and policymakers should be more concerned with the volatility in carry trade.
Investigating China's Disaggregated Processed Exports: Evidence that Both the RMB and Exchange Rates in Supply Chain Countries Matter
Authors: Thorbecke Willem
Published: June 2013

China's trade surplus is entirely in processing trade. Processed exports are final goods produced using parts and components coming from supply chain countries. Many claim that because much of the value added of China's processed exports comes from other countries, the renminbi should not affect China's processed exports. To investigate these issues, this paper disaggregates processed exports into their two main categories, processing with imported materials (PWIM) exports and processing and assembly (PAA) exports. For PWIM exports, much of the value added comes from China while for PAA exports most of the value added comes from supply chain countries. DOLS results indicate that exchange rates in supply chain countries affect both types of exports and that the renminbi significantly affects PWIM exports, but not PAA exports. These results indicate that both the renminbi and exchange rates in supply chain countries matter for processed exports.
An Asian Currency Unit: Simulations for Its Effects on East Asia
Authors: Yeh Kuo‐Chun
Published: June 2013

An Asian currency unit (ACU) is necessary to deepen Asian financial markets and to convert national currencies into a single monetary policy. However, the experiences of the European Currency Unit and the European Exchange Rate Mechanism crisis in 1992–93 have indicated the danger of the so‐called gradual approach. This study evaluates the effects of welfare should the ACU indicator become a long‐term constraint of the People's Republic of China and Japan, the big two in East Asia. Our results indicate that the constraints of countries’ own baskets (e.g. real effective exchange rates) are still better before the launch of a true single currency. That is, pegging to an ACU indicator could hardly be sustained in the long‐run if East Asian countries have not reached a consensus about a regional monetary union.
Experimental Analysis of the Interaction Between Rim Seal and Main Annulus Flow in a Low Pressure Two Stage Axial Turbine
Authors: Schrewe Sebastian , Werschnik Holger , Schiffer Heinz-Peter
Published: June 2013

The spoiling effects of rim seal flow are studied at the Large Scale Turbine Rig (LSTR) at Technische Universität Darmstadt. Detailed flow field measurements and efficiency measurements were performed for various ingress and egress setups and will be presented in this paper. Efficiency measurements show an efficiency decrease as the rim seal mass flow is increased. Five hole probe measurements upstream and downstream of the second stator row show that an increasing rim seal mass flow leads to an increased pressure loss across the stator, to altered incidence angles and to an intensification of secondary flow structures within the lower 50% span. Static pressure taps at the stator profile primarily show altered aerodynamic loading with increased rim seal air. In addition, the end wall profile pressure was measured at the stator 2 hub. It can be seen that seal air injection causes increased pressure fluctuations on the platform. Temperature measurements with a temperature difference between rim seal and main annulus flow show that rim seal air primarily enters the passage vortex.
Modeling Liquid Film Evaporation in a Wetted Wall Bioaerosol Sampling Cyclone
Authors: Hubbard J. A. , Ezekoye O. A. , Haglund J. S.
Published: June 2013

The wetted wall bioaerosol sampling cyclone (WWC) is a complex multiphase flow device which collects and concentrates dilute bioaerosols into liquid samples for biological analysis (McFarland et al., 2009, “Wetted Wall Cyclones for Bioaerosol Sampling,” Aerosol Sci. Technol., 44(4), pp. 241–252). Understanding heat and mass transfer processes occurring inside the WWC is the key to enhancing its performance through an effective coupling to lab-on-chip analysis platforms which require small volumes of liquid output. There exists a critical liquid input rate below which there is no sample collection since all liquid is lost to evaporative effects. The purpose of this study was to model critical film evaporation based on first principles and develop semi-empirical WWC performance correlations as an improvement to existing empirical correlations. A one-dimensional, coupled heat and mass transfer model was developed approximating WWC multiphase flow as cocurrent air-film flow. Governing equations were simplified and approximate solutions were used to optimize model parameters like the heat transfer coefficient based on empirical data from previous works. Optimized model parameters were then used in the full numerical solution to calculate liquid evaporation rates within the WWC over the full range of relative humidity and air temperature. Semi-empirical correlations developed in this study were compared to existing empirical models and showed much improvement: proper physical behavior at the extreme limits of temperature and relative humidity was observed, and the nonlinear dependence of evaporative effects on environmental conditions was also captured.
Method for Determining Instantaneous Temperature at the Surface of Combustion Chamber Deposits in an HCCI Engine
Authors: Güralp Orgun , Najt Paul , Filipi Zoran S.
Published: June 2013

Homogeneous charge compression ignition (HCCI) combustion is widely regarded as an attractive option for future high efficiency gasoline engines. HCCI combustion permits operation with a highly dilute, well mixed charge, resulting in high thermal efficiency and extremely low NOx and soot emissions, two qualities essential for future propulsion system solutions. Because HCCI is a thermokinetically dominated process, full understanding of how combustion chamber boundary thermal conditions affect the combustion process are crucial. This includes the dynamics of the effective chamber wall surface temperature, as dictated by the formation of combustion chamber deposits (CCD). It has been demonstrated that, due to the combination of CCD thermal properties and the sensitivity of HCCI to wall temperature, the phasing of autoignition can vary significantly as CCD coverage in the chamber increases. In order to better characterize and quantify the influence of CCDs, a numerical methodology has been developed which permits calculation of the crank-angle resolved local temperature profile at the surface of a layer of combustion chamber deposits. This unique predictor-corrector methodology relies on experimental measurement of instantaneous temperature underneath the layer, i.e., at the metal-CCD interface, and known deposit layer thickness. A numerical method for validation of these calculations has also been devised. The resultant crank-angle resolved CCD surface temperature and heat flux profiles both on top and under the CCD layer provide valuable insight into the near wall phenomena, and shed light on the interplay between the dynamics of the heat transfer process and HCCI burn rates.
Experimental Feasibility Study of Radial Injection Cooling of Three-Pad Air Foil Bearings
Authors: Shrestha Suman K. , Kim Daejong , Cheol Kim Young
Published: June 2013

The foil bearing (FB) is one type of hydrodynamic bearing using air or another gas as a lubricant. When FBs are designed, installed, and operated properly, they are a very cost-effective and reliable solution for oil-free turbomachinery. Because there is no mechanical contact between the rotor and its bearings, quiet operation with very low friction is possible once the rotor lifts off the bearings. However, because of the high speed of operation, thermal management is a very important design factor to consider. The most widely accepted cooling method for FBs is axial flow cooling, which uses cooling air or gas passing through heat-exchange channels formed underneath the top foil. The advantage of axial cooling is that no hardware modification is necessary to implement it, because the elastic foundation structures of the FB serve as the heat-exchange channels. Its disadvantage is that an axial temperature gradient exists on the journal shaft and bearing. In this paper, the cooling characteristics of axial cooling are compared with those of multipoint radial injection, which uses high-speed injection of cooling air onto the shaft at multiple locations. Experiments were performed on a three-pad FB 49 mm in diameter and 37.5 mm in length, at speeds of 30,000 rpm and 40,000 rpm. Injection speeds were chosen to be higher than the journal surface speed, but the total cooling air flow rate was matched to that of the axial cooling cases. Experimental results show that radial injection cooling is comparable to axial cooling at 30,000 rpm, in terms of cooling performance. Tests at 40,000 rpm reveal that the axial cooling performance reaches saturation when the pressure drop across the bearing is larger than 1000 Pa, while the cooling performance of radial injection is proportional to the cooling air flow rate and does not become saturated. Overall, multipoint radial injection is better than axial cooling at high rotor speeds.
Generalized separable parameter space techniques for fitting 1K‐5K serial compartment models
Authors: Kadrmas Dan J. , Oktay M. Bugrahan
Published: June 2013

Purpose:

Kinetic modeling is widely used to analyze dynamic imaging data, estimating kinetic parameters that quantify functional or physiologic processesin vivo. Typical kinetic models give rise to nonlinear solution equations in multiple dimensions, presenting a complex fitting environment. This work generalizes previously described separable nonlinear least‐squares techniques for fitting serial compartment models with up to three tissue compartments and five rate parameters.

Methods:

The approach maximally separates the linear and nonlinear aspects of the modeling equations, using a formulation modified from previous basis function methods to avoid a potential mathematical degeneracy. A fast and robust algorithm for solving the linear subproblem with full user‐defined constraints is also presented. The generalized separable parameter space technique effectively reduces the dimensionality of the nonlinear fitting problem to one dimension for 2K‐3K compartment models, and to two dimensions for 4K‐5K models.

Results:

Exhaustive search fits, which guarantee identification of the true global minimum fit, required approximately 10 ms for 2K‐3K and 1.1 s for 4K‐5K models, respectively. The technique is also amenable to fast gradient‐descent iterative fitting algorithms, where the reduced dimensionality offers improved convergence properties. The objective function for the separable parameter space nonlinear subproblem was characterized and found to be generally well‐behaved with a well‐defined global minimum. Separable parameter space fits with the Levenberg‐Marquardt algorithm required fewer iterations than comparable fits for conventional model formulations, averaging 1 and 7 ms for 2K‐3K and 4K‐5K models, respectively. Sensitivity to initial conditions was likewise reduced.

Conclusions:

The separable parameter space techniques described herein generalize previously described techniques to encompass 1K‐5K compartment models, enable robust solution of the linear subproblem with full user‐defined constraints, and are amenable to rapid and robust fitting using iterative gradient‐descent type algorithms.
Long-term mortality rates and spatial patterns in an old-growth Pinus resinosa forest
Authors: Silver Emily J. , Fraver Shawn , D’Amato Anthony W. , Aakala Tuomas , Palik Brian J.
Published: June 2013

Understanding natural mortality patterns and processes of forest tree species is increasingly important given projected changes in mortality owing to global change. With this need in mind, the rate and spatial pattern of mortality was assessed over an 89-year period in a natural-origin Pinus resinosa (Aiton)-dominated system to assess these processes through advanced stages of stand development (stand age 120–209 years). Average annual mortality rates fluctuated through time, yet were within the range reported in other studies (0.60%–3.88% depending on species and sampling interval). Tree mortality was attributed to multiple agents, including the senescence of the short-lived Pinus banksiana Lamb., windthrow, root-rot fungi (Armillaria ostoyae (Romagn.) Herink), and perhaps infrequent droughts. Despite the often contagious nature of many disturbance agents, the overall spatial pattern of mortality events (the arrangement of dead trees within the fixed initial population of live trees) was random at all scales tested. Similarly, the current spatial pattern of dead trees was predominantly random, despite clustering at small scales (2–4 m). These findings underscore the importance of studying mortality rates, agents, and spatial patterns over long time periods to avoid misinterpreting stochastic mortality events, and their influence on longer term stand structure and development.
RELATIVISTIC DIFFUSION OF QUARKS IN RANDOM GLUON FIELDS
Authors: HABA Z.
Published: June 2013

We consider Wong's equations for a particle with a continuous mass spectrum in a random Yang–Mills field approximating the quantum field at finite temperature. We show that particle time evolution can be approximated by a relativistic diffusion. Kubo's generator of the relativistic diffusion is defined as an expectation value of the square of the Liouville operator.
NONPARALLEL HYPERPLANES PROXIMAL CLASSIFIERS BASED ON MANIFOLD REGULARIZATION FOR LABELED AND UNLABELED EXAMPLES
Authors: YANG ZHI-XIA
Published: June 2013

In this paper, we propose two Laplacian nonparallel hyperplane proximal classifiers (LapNPPCs) for semi-supervised and full-supervised classification problem respectively by adding manifold regularization terms. Due to the manifold regularization terms, our LapNPPCs are able to exploit the intrinsic structure of the patterns of the training set. Furthermore, our classifiers only need to solve two systems of linear equations rather than two quadratic programming (QP) problems as needed in Laplacian twin support vector machine (LapTSVM) (Z. Qi, Y. Tian and Y. Shi, Neural Netw.35 (2012) 46–53). Numerical experiments on toy and UCI benchmark datasets show that the accuracy of our LapNPPCs is comparable with other classifiers, such as the standard SVM, TWSVM and LapTSVM, etc. It is also the case that based on our LapNPPCs, some other TWSVM type classifiers with manifold regularization can be constructed by choosing different norms and loss functions to deal with semi-supervised binary and multi-class classification problems.
CONGRUENCES FOR k DOTS BRACELET PARTITION FUNCTIONS
Authors: CUI SU-PING , GU NANCY SHAN SHAN
Published: June 2013

Andrews and Paule introduced broken k-diamond partitions by using MacMahon's partition analysis. Recently, Fu found a generalization which he called k dots bracelet partitions and investigated some congruences for this kind of partitions. In this paper, by finding congruence relations between the generating function for 5 dots bracelet partitions and that for 5-regular partitions, we get some new congruences modulo 2 for the 5 dots bracelet partition function. Moreover, for a given prime p, we study arithmetic properties modulo p of k dots bracelet partitions.
ON AUTOMORPHISMS OF EXTREMAL EVEN UNIMODULAR LATTICES
Authors: NEBE GABRIELE
Published: June 2013

The automorphism groups of the three known extremal even unimodular lattices of dimension 48 and the one of dimension 72 are determined using the classification of finite simple groups. Restrictions on the possible automorphisms of 48-dimensional extremal lattices are obtained. We classify all extremal lattices of dimension 48 having an automorphism of order m with φ(m) > 24. In particular the lattice P48nis the unique extremal 48-dimensional lattice that arises as an ideal lattice over a cyclotomic number field.
MULTIPLE HARMONIC SUMS AND WOLSTENHOLME'S THEOREM
Authors: ROSEN JULIAN
Published: June 2013

We give a family of congruences for the binomial coefficient [Formula: see text], with k an integer and p a prime. Our congruences involve multiple harmonic sums, and hold modulo arbitrary large powers of p. The general congruence in our family, which depends on a parameter n, involves n "elementary symmetric" multiple harmonic sums, and holds modulo p2n+3. These congruences are actually part of a much larger collection of congruences for [Formula: see text] in terms of the elementary symmetric multiple harmonic sums. Congruences in our family have been optimized, in that they involve the fewest multiple harmonic sums among those congruences holding modulo the same power of p. The coefficients in our congruences are given by polynomials in k.
NONLINEAR SPECTRAL IMAGING OF ELASTIC CARTILAGE IN RABBIT EARS
Authors: CHEN JING , GUO CHUNGEN , LI HONGSHENG , ZHU XIAOQIN , XIONG SHUYUAN , CHEN JIANXIN
Published: June 2013

Elastic cartilage in the rabbit external ear is an important animal model with attractive potential value for researching the physiological and pathological states of cartilages especially during wound healing. In this work, nonlinear optical microscopy based on two-photon excited fluorescence and second harmonic generation were employed for imaging and quantifying the intact elastic cartilage. The morphology and distribution of main components in elastic cartilage including cartilage cells, collagen and elastic fibers were clearly observed from the high-resolution two-dimensional nonlinear optical images. The areas of cell nuclei, a parameter related to the pathological changes of normal or abnormal elastic cartilage, can be easily quantified. Moreover, the three-dimensional structure of chondrocytes and matrix were displayed by constructing three-dimensional image of cartilage tissue. At last, the emission spectra from cartilage were obtained and analyzed. We found that the different ratio of collagen over elastic fibers can be used to locate the observed position in the elastic cartilage. The redox ratio based on the ratio of nicotinamide adenine dinucleotide (NADH) over flavin adenine dinucleotide (FAD) fluorescence can also be calculated to analyze the metabolic state of chondrocytes in different regions. Our results demonstrated that this technique has the potential to provide more accurate and comprehensive information for the physiological states of elastic cartilage.
BOUNDING THE NUMBER OF REDUCED TREES, COGRAPHS, AND SERIES-PARALLEL GRAPHS BY COMPRESSION
Authors: UNO TAKEAKI , UEHARA RYUHEI , NAKANO SHIN-ICHI
Published: June 2013

We give an efficient encoding and decoding scheme for computing a compact representation of a graph in one of unordered reduced trees, cographs and series-parallel graphs. The unordered reduced trees are rooted trees in which (i) the ordering of children of each vertex does not matter, and (ii) no vertex has exactly one child. This is one of basic models frequently used in many areas. Our algorithm computes a bit string of length 2ℓ – 1 for a given unordered reduced tree with ℓ ≥ 1 leaves in O(ℓ) time, whereas a known folklore algorithm computes a bit string of length 2n – 2 for an ordered tree with n vertices. Note that in an unordered reduced tree, ℓ ≤ n < 2ℓ holds. To the best of our knowledge this is the first of such a compact representation for unordered reduced trees. From the theoretical point of view, the length of the representation gives us an upper bound of the number of unordered reduced trees with ℓ leaves. Precisely, the number of unordered reduced trees with ℓ leaves is at most 22ℓ–2 for ℓ ≥ 1. Moreover, the encoding and decoding can be done in linear time. Therefore, from the practical point of view, our representation is also useful to store a lot of unordered reduced trees efficiently. We also apply the scheme for computing a compact representation to cographs and series-parallel graphs. We show that each of cographs with n vertices has a compact representation in 2n – 1 bits, and the number of cographs with n vertices is at most 22n–1. The resulting number is close to the number of cographs with n vertices obtained by the enumeration for small n that approximates Cdn/n3/2, where C = 0.4126⋯ and d = 3.5608⋯. Series-parallel graphs are well-investigated in the context of the graphs of bounded treewidth. We give a method to represent a series-parallel graph with m edges in ⌈2.5285m – 2⌉ bits. Hence the number of series-parallel graphs with m edges is at most 2⌈2.5285m–2⌉. As far as the authors know, this is the first non-trivial result about the number of series-parallel graphs. The encoding and decoding of the cographs and series-parallel graphs also can be done in linear time.
INFERRING STRINGS FROM COVER ARRAYS
Authors: MOOSA TANAEEM M. , NAZEEN SUMAIYA , RAHMAN M. SOHEL , REAZ REZWANA
Published: June 2013

Covers, being one of the most popular form of regularities in strings, have drawn much attention in the relevant literature. In this paper, we focus on the problem of linear-time inference of strings from cover arrays using the least sized alphabet. We present an algorithm that can reconstruct a string x over a binary alphabet whenever a valid cover array C is given as an input. We have devised our algorithm using several interesting combinatorial properties of cover arrays as well as an interesting relation between border array and cover array. Our algorithm runs in linear-time. The fact that, from any valid cover array, we can infer a binary string x, is, in itself, a fascinating result in stringology, and this work may be considered as the final step for this particular problem area.
Practical Applications of Taguchi Method for Optimization of Processing Parameters for Plastic Injection Moulding: A Retrospective Review
Authors: Fei Ng Chin , Mehat Nik Mizamzul , Kamaruddin Shahrul
Published: June 2013

Determining the optimal processing parameter is routinely performed in the plastic injection moulding industry as it has a direct and dramatic influence on product quality and costs. In this volatile and fiercely competitive market, traditional trial-and-error is no longer sufficient to meet the challenges of globalization. This paper aims to review the research of the practical use of Taguchi method in the optimization of processing parameters for injection moulding. Taguchi method has been employed with great success in experimental designs for problems with multiple parameters due to its practicality and robustness. However, it is realized that there is no single technique that appears to be superior in solving different kinds of problem. Improvements are to be expected by integrating the practical use of the Taguchi method into other optimization approaches to enhance the efficiency of the optimization process. The review will shed light on the standalone Taguchi method and integration of Taguchi method with various approaches including numerical simulation, grey relational analysis (GRA), principal component analysis (PCA), artificial neural network (ANN), and genetic algorithm (GA). All the features, advantages, and connection of the Taguchi-based optimization approaches are discussed.
Optimum Groove Location of Hydrodynamic Journal Bearing Using Genetic Algorithm
Authors: Roy Lintu , Kakoty S. K.
Published: June 2013

This paper presents the various arrangements of grooving location of two-groove oil journal bearing for optimum performance. An attempt has been made to find out the effect of different configurations of two groove oil journal bearing by changing groove locations. Various groove angles that have been considered are 10°, 20°, and 30°. The Reynolds equation is solved numerically in a finite difference grid satisfying the appropriate boundary conditions. Determination of optimum performance is based on maximization of nondimensional load, flow coefficient, and mass parameter and minimization of friction variable using genetic algorithm. The results using genetic algorithm are compared with sequential quadratic programming (SQP). The two grooved bearings in general have grooves placed at diametrically opposite directions. However, the optimum groove locations, arrived at in the present work, are not diametrically opposite.
Robot-Assisted Navigation versus Computer-Assisted Navigation in Primary Total Knee Arthroplasty: Efficiency and Accuracy
Authors: Clark Tanner C. , Schmidt Frank H.
Published: June 2013

Background. Since the introduction of robot-assisted navigation in primary total knee arthroplasty (TKA), there has been little research conducted examining the efficiency and accuracy of the system compared to computer-assisted navigation systems. Objective. To compare the efficiency and accuracy of Praxim robot-assisted navigation (RAN) and Stryker computer-assisted navigation (CAN) in primary TKA. Methods. This was a retrospective study consisting of 52 patients who underwent primary TKA utilizing RAN and 29 patients utilizing CAN. The primary outcome measure was navigation time. Secondary outcome measures included intraoperative final mechanical axis alignment, intraoperative robot-assisted bone cut accuracy, tourniquet time, and hospitalization length. Results. RAN navigation times were, on average, 9.0 minutes shorter compared to CAN after adjustment. The average absolute intraoperative malalignment was 0.5° less in the RAN procedures compared to the CAN procedures after adjustment. Patients in the RAN group tended to be discharged 0.6 days earlier compared to patients in the CAN group after adjustment. Conclusions. Among patients undergoing TKA, there was decreased navigation time, decreased final malalignment, and decreased hospitalization length associated with the use of RAN when compared to CAN independent of age, BMI, and pre-replacement alignment.