bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulmonary hypertension associated with sickle cell disease: Clinical and laboratory endpoints and disease outcomes
Authors: De Castro Laura M. , Jonassaint Jude C. , Graham Felicia L. , Ashley‐Koch Allison , Telen Marilyn J. 
Published: August 2007

AbstractScreening for pulmonary hypertension (pHTN) has not yet become routine in sickle cell disease (SCD), despite clinical evidence of its high prevalence and associated mortality. Our objectives are to identify clinical conditions and laboratory findings predictive of/or associated with pHTN. One hundred twenty‐five adult outpatients with Hb SS, SC, SOArab, Sβ0, or Sβ+ thalassemia, who underwent echocardiography and/or right heart catheterization due to cardiorespiratory symptoms, were studied. pHTN was identified in 36% (28/77) of SS/Sβ0 and in 25% (12/48) of SC/SOArab/Sβ+ patients studied. In SS/Sβ0 patients, pHTN was associated with low hemoglobin, low GFR, increasing age, no history of treatment with hydroxyurea and a history of leg ulcers, with trends for associations with higher total bilirubin, LDH levels, systolic systemic blood pressure, history of avascular necrosis, seizures, and cerebrovascular events. Twelve (40%) of the SS/Sβ0 patients with pHTN had ≥1+ proteinuria. (P < 0.039). The presence of proteinuria correlated with lower GFR and had a high positive predictive value (0.60) for pHTN in subjects with SS/Sβ0. The data also provided evidence that pHTN in this population is associated with right heart failure, with echocardiographic evidence of right ventricle enlargement and pericardial effusion. This study confirmed that even relatively mild elevations in pulmonary pressure are associated with high prospective mortality (hazard ratio: 15.9). We concluded that pHTN has a high prevalence in all Hb S related syndromes and is associated with increased mortality in SS/Sβ0. Kidney dysfunction, as indicated by proteinuria or decreased GFR, also represents sufficient reason to screen for pHTN. Am. J. Hematol., 2008. © 2007 Wiley‐Liss, Inc.
Plant performance test for the de‐ethanizer overhead recycle (DOR) process
Authors: Trebble M. A. 
Published: August 2007

AbstractThe de‐ethanizer overhead recycle (DOR) process was successfully performance‐tested at the Joffre ethane extraction plant (JEEP) in Alberta, Canada, in May 2005. The test confirmed simulation results used in patenting the process and were slightly better than predicted. At the lowest test recycle rate, the CO2 content in the produced ethane was reduced from 5.4 to 4.5 mole% with only a slight drop in ethane recovery from 90.4 to 90.0%. Increasing the recycle to a higher level reduced the CO2 content to 4.1% at an ethane recovery level of 88.8%. The process showed excellent operability and was effective for reducing both CO2 and methane from a commercial ethane product stream. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
CFD modeling of columns equipped with structured packings: I. Approach based on detailed packing geometry
Authors: Wen X. , Akhter S. , Afacan A. , Nandakumar K. , Chuang K. T. 
Published: August 2007

AbstractA three‐dimensional computational fluid dynamics (CFD) modeling approach based on detailed packing geometry for packed columns equipped with structured packings is presented. Simulations have been carried out by commercial CFD package FLUENT. Complex packing geometries were implemented by generating fine meshes for flow domains inside packed columns. Turbulence was modeled by the standard k‐ϵ model with FLUENT's enhanced wall treatment. Experiments on single‐phase pressure drop through Flexipac 3Y structured packing have been carried out in a 0.3‐m ID packed column with air flow to validate the modeling approach. A circular column and a rectangular column have been simulated with three different structured packings—BX packing with corrugation angles of 45° and 30° and Flexipac 3Y. One‐component single‐phase flow and two‐component single‐phase flow with species dispersion (mass transfer) have been simulated. Predicted pressure drop are in good agreement with the experimental data and data from literatures. The simulation results also demonstrated the ability of the CFD approach to capture the anisotropic characteristic of flow in structured packings. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Effect of solvent exchange on the structure and rheological properties of cellulose in LiCl/DMAc
Authors: Wei Yuping , Cheng Fa 
Published: August 2007

AbstractEffect of solvent exchange on the structure of cellulose was investigated by Fourier transform infrared spectroscopy, wide angle X‐ray diffraction, and scanning electron microscopy analysis. The solvent exchange facilitated the dissolution of cellulose in LiCl/DMAc with no change of the crystalline structure of cellulose. In contrast, solvent exchange led to the fibrillation on the treated fiber surface and the trimmed rod‐like particles, further confirming the occurrence of particle disintegration. The rheological properties of three cellulose samples with different degrees of polymerization (DP) and different concentrations were investigated. Results indicated that the cellulose LiCl/DMAc solutions were non‐Newtonian fluids. At low deformation rates the cellulose solution behaved like a viscous liquid (loss modulus G″ being larger than storage modulus G′), but elastic properties developed at high angular frequency. The two domains of viscoelastic behavior were separated by the so‐called crossover point for G′ and G″, which was slightly shifted to lower frequencies as the testing temperature increased from 50 to 80°C. As the concentration and the average molecular weight (or DP) increased, the angular frequency at the crossover point increased also under the experimental conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Late Deposition of Elastin to Vertical Microfibrillar Fibers in the Presumptive Dermis of the Chick Embryonic Tarsometatarsus
Authors: Yamazaki Yosuke , Sejima Hitomi , Yuguchi Maki , Namba Yuichi , Isokawa Keitaro 
Published: August 2007

AbstractFibrillin microfibrils are integral components of elastic fibers and serve as a scaffold for elastin deposition. However, microfibrillar fibers (MFs) are not necessarily committed to develop into so‐called elastic fibers. In dermis, elastin‐free oxytalan MFs originating from the dermoepidermal junction are continuous to elaunin‐type MFs (with a small amount of elastin) in the deeper papillary dermis, whereas the reticular dermis contains elastic fibers, or MFs embedded largely in elastin. In this study, we have investigated temporospatial patterns of elastin deposition on the MFs in tarsometatarsal presumptive dermis. While the earliest expression of elastin was demonstrated immunohistochemically as early as embryonic day 4 (ED4) in the wall of cardiac outflow and pharyngeal arch arteries, its deposition in the tarsometatarsus was first detected at ED6 in the deeper mesenchyme and at ED13 in the subectodermal mesenchyme. In the latter tissue, MFs had been organized perpendicularly to the covering ectoderm by ED4, well before an overt accumulation of collagenous matrix. Elastin deposition was observed initially in a punctate manner at ED13 and afterward became continuous along MFs. However, a characteristic spaced array of subectodermal vertical MFs was disorganized by ED17. These findings suggest that elastin deposition in the subectodermal MFs is not deployed by continuous, orderly propagation from elastic fibers in the deeper mesenchyme but occurs de novo in multiple foci along vertical MFs. Moreover, the present chronology of elastin deposition indicates that subectodermal, elastin‐free MFs function as a transient, but primary fibrous structure in the presumptive dermis before the accumulation of collagenous matrix. Anat Rec, 290:1300‐1308, 2007. © 2007 Wiley‐Liss, Inc.
Numerische Simulation des Verhaltens von Betontragwerken unter Brandeinwirkung
Authors: Aschaber Matthias , Feist Christian , Hofstetter Günter 
Published: August 2007

AbstractDas in diesem Beitrag vorgestellte numerische Rechenmodell für Beton‐ und Stahlbetonstrukturen unter Brandeinwirkung umfasst die instationäre thermische und mechanische Analyse unter Berücksichtigung der Temperaturabhängigkeit der thermischen und mechanischen Eigenschaften des Betons und des Bewehrungsstahls im Rahmen des im Eurocode 2, Teil 1‐2, enthaltenen phänomenologischen Ansatzes. Als Grundlage für das konstitutive Modell für Beton unter hohen Temperaturen dient ein auf der Plastizitätstheorie in Kombination mit der Schädigungsmechanik beruhendes Werkstoffmodell, für den Bewehrungsstahl wird ein elasto‐plastisches Materialmodell verwendet. Das vorgestellte Rechenmodell wird anhand der numerischen Simulation von Brandversuchen an scheibenförmigen Betonprobekörpern und eines Großversuches an einer Stahlbetonplatte unter Brandeinwirkung überprüft und zur Prognose des Tragverhaltens eines in offener Bauweise hergestellten Tunnelbauwerks unter Brandeinwirkung angewendet.
Untersuchung nichtlinearer Schwingungseigenschaften zur zerstörungsfreien Zustandsprüfung am Beispiel von Stahlbetonbalken
Authors: Waltering Markus , Waldmann Danièle , Maas Stefan , Zürbes Arno 
Published: August 2007

AbstractIngenieurbauwerke, im Speziellen Straßen‐ und Bahnbrücken, sind ein unverzichtbarer Bestandteil der Infrastruktur eines Landes. Um eine möglichst lange und wirtschaftliche Nutzung dieser Bauwerke zu ermöglichen, werden an Brücken regelmäßige Inspektionen durchgeführt. Die herkömmliche und am weitesten verbreitete Methode der Zustandsanalyse ist die visuelle Prüfung durch erfahrene Ingenieure. Dabei können jedoch ausschließlich äußere Anzeichen einer Schädigung festgestellt werden. Je nach Bauwerksgröße kann eine entsprechende Prüfung Tage bis Wochen in Anspruch nehmen. In besonderen Fällen kommen sehr kosten‐ und zeitintensive Belastungsversuche zum Einsatz. Seit einigen Jahren kommen immer häufiger Methoden zur Anwendung, welche die dynamischen Eigenschaften zur Zustandsbewertung nutzen. Im Rahmen dieses Aufsatzes werden Versuche an Stahlbetonbalken vorgestellt, bei denen die Untersuchung nichtlinearen Schwingungsverhaltens im Vordergrund steht. Damit soll ein Beitrag für die mögliche und zukünftige Beurteilung des nichtlinearen Schwingungsverhaltens zur Zustandsbewertung im Rahmen von Brückeninspektionen geleistet werden.
Incorporation of Inter‐individual Heterogeneity into the Multistage Carcinogenesis Model: Approach to the Analysis of Cancer Incidence Data
Authors: Izumi Shizue , Ohtaki Megu 
Published: August 2007

AbstractWe investigate a multistage carcinogenesis frailty model to incorporate inter‐individual heterogeneity into carcinogenic response. Attention is focused on inference concerning the effects of different sources of population heterogeneity on cancer rates. The authors consider unobserved variability arising from either carcinogen exposure or background characteristics. Gamma and Inverse‐Gaussian distributions are selected for frailty models, and the baseline hazard function is the generalized Armitage‐Doll model (i.e. non‐frailty model) in which exposure effects shift the age scale instead of acting multiplicatively on cancer rates. For illustration, we apply the method to solid cancer data from a cohort of atomic bomb survivors to examine some features of proposed models. The results show that the Gamma frailty model for the heterogeneity of baseline rates provides the best goodness‐of‐fit of the model and a non‐zero frailty variance. Parameter estimates are, for the most part, comparable between the Gamma and Inverse‐Gaussian frailty models. In a heterogeneous population the exposure effects on young adulthood cancer rates might be underestimated for the non‐frailty model. Meaningful information regarding each source of heterogeneity has been provided by the proposed method. Therefore, the multistage carcinogenesis frailty model approach is useful for analyses of epidemiological cancer data to assess population heterogeneity and heterogeneity‐influenced exposure effects. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bonferroni Parallel Gatekeeping – Transparent Generalizations, Adjusted P ‐values, and Short Direct Proofs
Authors: Guilbaud Olivier 
Published: August 2007

AbstractIn the two‐step version (Dmitrienko, Tamhane, Wang and Chen, 2006) of the Bonferroni parallel‐gatekeeping multiple‐testing procedure (MTP): (a) a family F1 of null hypotheses H is used as a gatekeeper for another family F2 in that no H in F2 can be rejected unless at least one H is rejected in F1; (b) a Bonferroni MTP is used for F1 at local multiple‐level alpha in the first step; and (c) Holm's (1979) step‐down MTP is used in the second step for F2 at a local multiple level that depends on the rejections made in the first step. It is shown in this article that this two‐step procedure can be generalized in that any MTP with multiple‐level control and available multiplicity‐adjusted p ‐values can be used instead of Holm's MTP in the second step. A further generalization related to what Dmitrienko, Molenberghs, Chuang‐Stein and Offen (2005) called modified Bonferroni parallel gatekeeping is also given where in case all H s in F2 are rejected, additional rejections in F1 can be made in a third step at local multiple‐level alpha through any MTP that is more powerful than the initial Bonferroni MTP, e.g. Holm's MTP. The proofs that these two generalized Bonferroni parallel‐gatekeeping MTPs have multiple‐level alpha are short and direct, without closed‐testing arguments. Multiplicity‐adjusted p ‐values can easily be calculated for these MTPs. The extensions to several successive gatekeeper families are straightforward. An illustration is given. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A General Approach to Sample Size Determination for Prevalence Surveys that Use Dual Test Protocols
Authors: Cheng Dunlei , Stamey James D. , Branscum Adam J. 
Published: August 2007

AbstractWe develop a Bayesian simulation based approach for determining the sample size required for estimating a binomial probability and the difference between two binomial probabilities where we allow for dependence between two fallible diagnostic procedures. Examples include estimating the prevalence of disease in a single population based on results from two imperfect diagnostic tests applied to sampled individuals, or surveys designed to compare the prevalences of two populations using diagnostic outcomes that are subject to misclassification. We propose a two stage procedure in which the tests are initially assumed to be independent conditional on true disease status (i.e. conditionally independent). An interval based sample size determination scheme is performed under this assumption and data are collected and used to test the conditional independence assumption. If the data reveal the diagnostic tests to be conditionally dependent, structure is added to the model to account for dependence and the sample size routine is repeated in order to properly satisfy the criterion under the correct model. We also examine the impact on required sample size when adding an extra heterogeneous population to a study. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Effect of Pulsed Direct Current Field on the Membrane Flux of a New Style of Membrane Bioreactor
Authors: Chen J.‐P. , Yang C.‐Z. , Zhou J.‐H. 
Published: August 2007

AbstractThe effect of a pulsed direct current electric field on the membrane flux of an antifouling Membrane Bioreactor (MBR) designed and built in the laboratory was studied. The results showed that a pulsed direct current electric field had a significant effect on the membrane flux. The average membrane flux when using a pulse direct current electric field was between that of a steady electric field and that of no electric current under a trans‐membrane pressure drop of ΔP = 0.1 MPa and a pulsed direct current electric field strength of 20 V/cm. There was an optimum value of pulse intensity and pulse duration for the membrane flux. The shorter the pulse interval time was, the higher the frequency of power‐on, and the higher the average stable membrane flux of the MBR. This may have resulted from the fact that charged coarse particles and colloids account for 80 % of CODcr and BOD5 in urban domestic sewage. These particles and colloids moved away from the membrane surface at a certain electrical field strength, gradually thinning the particle sedimentary layer, reducing the membrane filtration resistance, and increasing the membrane flux significantly. However, the formation of a sedimentary layer on the membrane surface needed a significant amount of time and an appropriate pulse frequency while the MBR is powered on. This could save energy while keeping the membrane clean.
Size Distribution of Drops Formed from Nozzles in Air at Velocities below Jetting
Authors: Koimpsidis L. , Papanikolaou M. , Stamatoudis M. 
Published: August 2007

AbstractThe drop size distribution of drops formed from four nozzles (d = 0.5, 1.8, 2.7 and 3.6 mm) were measured for the flow rate range Q = 0.1–1.17 cm3/s and Reynolds number 56–448. Distilled water was used as the dispersed phase and air as the continuous one. The experimental drop size distributions were described satisfactorily by the theoretical upper limit number and volume distributions. The experimental data of minimum and maximum diameters versus the respective Sauter mean diameters gave straight lines with slopes of 0.81 and 1.18, respectively.
Characterization of Candida rugosa Lipase Immobilized on Poly(N‐methylolacrylamide) and Its Application in Butyl Butyrate Synthesis
Authors: Santos J. C. , Nunes G. F. M. , Moreira A. B. R. , Perez V. H. , de Castro H. F. 
Published: August 2007

AbstractCandida rugosa lipase was immobilized on poly(N‐methylolacrylamide) by physical adsorption. The biocatalyst performance (immobilized lipase) was evaluated in both aqueous (hydrolysis) and organic (butyl butyrate synthesis) media. In the first case, a comparative study between free and immobilized derivatives was provided in terms of pH, temperature and thermal stability following the olive oil hydrolysis, establishing new optimum values. In the second case, the influence of temperature, biocatalyst concentration and acid/alcohol molar ratio was simultaneously studied according to a 23 full experimental design. The highest molar conversion (96 %), volumetric productivity (1.73 g L–1 h–1) and specific esterification activity (1.00 μM mg–1 min–1) were obtained when working at the lowest level of temperature and butyric acid in excess. Under these conditions, repeated batch use of the immobilized enzyme was performed and half‐life time (t1/2) was found to be 145 h.
Temperature Control of a Bench‐Scale Batch Polymerization Reactor for Polystyrene Production
Authors: Ghasem N. M. , Sata S. A. , Hussain M. A. 
Published: August 2007

AbstractBatch polymerization reactors commonly use optimal temperature control as the strategic operation parameter. This strategy allows for better operability and a more economic process. The main objective of the batch polymerization reactor control is to obtain acceptable product quality. Direct measurement of polymer quality is rarely achievable, which makes the online control of the reactor difficult. Temperature is the most controllable operational variable in the polymer reactor, which is seen to have a direct effect on the polymer properties. Temperature is chosen as the set point by using either the isothermal temperature or optimal temperature trajectory. Online control of the optimal temperature profile of a bench‐scale batch polymerization reactor was experimentally investigated in this study. The temperature trajectory was used as the target for controllers to follow. The time‐profile temperature was obtained with the objective of obtaining the desired conversion and number‐average chain length within the minimum time. Two advanced controls of fuzzy logic control and generic model control were applied to the polymer reactor. A comparison of the controllers reveals that both performed better than conventional controllers.
The Study of Molecular Modeling for Heavy Oil Thermal Cracking
Authors: Yan L. , Zhang X.‐P. , Zhang S.‐J. 
Published: August 2007

AbstractThe tighter specifications for refining products have gradually led refineries to focus on the molecular modeling of petroleum processing. In this work, a systematic methodology is presented for the molecular modeling of heavy oil thermal cracking (HOTC). This research which is based on a microscopic understanding provides a basis to achieve better design, management, optimization, and control of HOTC. The molecular information of HOTC product streams is represented in the form of a MTHS (molecular type homologous series) matrix. From consideration of the complexity of structural isomers in heavy petroleum fractions, the heavy molecules in a homologous series are grouped to reduce the dimension of the MTHS matrix. Transformation correlations are developed to capture the molecular properties of each homologous series in the MTHS matrix and to interrelate the molecular composition and bulk properties of the product streams. The HOTC process model was built on the basis of the molecular representation provided by the MTHS matrix and the transformation correlations. Two case studies are illustrated for validation of the proposed model and methodology.
The prediction of the circular dichroism of the benzene chromophore: TDDFT calculations and sector rules
Authors: Pescitelli Gennaro , Di Bari Lorenzo , Caporusso Anna Maria , Salvadori Piero 
Published: August 2007

AbstractThe CD spectra of the series PhCH(Me)R, with R = Et (1), nPr (2), iPr (3), and tBu (4), are reported (1–3 for the first time) at room temperature in the 185–280 nm range and at 183 K. These purely hydrocarbon compounds represent the simplest chiral systems containing the phenyl chromophore and exhibit Cotton effects exclusively allied with the benzene transitions. The bands in 1La and 1Lb regions were checked against the available sector rules, with discordant outcomes. Time‐dependent density‐functional theory calculations, with various functionals and basis sets tested, correctly reproduced the prominent CD bands observed for 1–4. Chirality, 2008. © 2007 Wiley‐Liss, Inc.
Political risk and the internationalization of firms: An empirical study of Canadian‐based export and FDI firms
Authors: Agarwal James , Feils Dorothee 
Published: August 2007

AbstractPolitical risk analysis primarily receives attention for foreign direct investment (FDI) but only rarely for exporting. We examine how exporters and foreign direct investors evaluate the relative importance of political risk factors. We provide a rationale for exporters to evaluate political risk factors for FDI and for foreign direct investors to evaluate political risk factors for exporting. Survey data were collected from Canadian exporters and foreign direct investors and capture the distinctive nature of salient factors for exporting and FDI. We offer unique insights on the evolutionary character of political risk that are of practical value for both exporting and FDI. Copyright © 2007 ASAC. Published by John Wiley & Sons, Ltd.