bluuebunny/crossref_metadata_2025 huggingface dataset:
Critical Role of Calpain I in Mitochondrial Release of Apoptosis-Inducing Factor in Ischemic Neuronal Injury
Authors: Cao Guodong , Xing Juan , Xiao Xiao , Liou Anthony K. F. , Gao Yanqin , Yin Xiao-Ming , Clark Robert S. B. , Graham Steven H. , Chen Jun
Published: August 2007

Loss of mitochondrial membrane integrity and release of apoptogenic factors are a key step in the signaling cascade leading to neuronal cell death in various neurological disorders, including ischemic injury. Emerging evidence has suggested that the intramitochondrial protein apoptosis-inducing factor (AIF) translocates to the nucleus and promotes caspase-independent cell death induced by glutamate toxicity, oxidative stress, hypoxia, or ischemia. However, the mechanism by which AIF is released from mitochondria after neuronal injury is not fully understood. In this study, we identified calpain I as a direct activator of AIF release in neuronal cultures challenged with oxygen–glucose deprivation and in the rat model of transient global ischemia. Normally residing in both neuronal cytosol and mitochondrial intermembrane space, calpain I was found to be activated in neurons after ischemia and to cleave intramitochondrial AIF near its N terminus. The truncation of AIF by calpain activity appeared to be essential for its translocation from mitochondria to the nucleus, because neuronal transfection of the mutant AIF resistant to calpain cleavage was not released after oxygen–glucose deprivation. Adeno-associated virus-mediated overexpression of calpastatin, a specific calpain-inhibitory protein, or small interfering RNA-mediated knockdown of calpain I expression in neurons prevented ischemia-induced AIF translocation. Moreover, overexpression of calpastatin or knockdown of AIF expression conferred neuroprotection against cell death in neuronal cultures and in hippocampal CA1 neurons after transient global ischemia. Together, these results define calpain I-dependent AIF release as a novel signaling pathway that mediates neuronal cell death after cerebral ischemia.
Museums and Mexican Indigenous Territoriality
Authors: Liffman Paul M.
Published: August 2007

Huichol Indians from western Mexico have contributed on various levels to exhibits about their culture, history and territoriality in Mexico's Museo Nacional de Antropología and the National Museum of the American Indian in Washington DC. The article compares these projects and their precursors since the 1930s in terms of changing modalities of institutional power, clientelism and indigenous agency. It also links this history to revalorizations of ethnic art and changing representations of culture and territory in legal claims. As Huichols engage new regional and global publics in these diverse contexts, they rework received images of sovereignty and the national space.
The Poetry Café Is Open! Teaching Literary Devices of Sound in Poetry Writing
Authors: Kovalcik Beth , Certo Janine L.
Published: August 2007

A six‐week long intervention that introduced second graders to poetry writing is described in this article, ending in a classroom “poetry cafe” culminating event. This article details the established classroom “writing workshop” structure and environment and the perceptions and observations of how students responded to the instruction. Four poetry writing minilessons on rhymed verse, repetition, alliteration, onomatopoeia, and collaborative poetry are highlighted. Poetry trade books were used as models. An intervention used to meet the needs of a struggling writer is explained. Finally, the article showcases the celebratory “Kovalcik Café” where second graders read aloud their published works to family and friends.
Application of partnering principles to a framework contract
Authors: Gullick D. , Cairns R. , Pearson-Kirk D.
Published: August 2007

Sir John Egan's report on Rethinking Construction advocated ‘long term relationships based on clear measurement of performance and sustained improvements in quality and efficiency’. In 2001, Northern Ireland Roads Service embarked on a three-year framework to review the work carried out on their stock of post-tensioned bridges. The contract adopted a partnering approach embodying the key principles recommended by Egan. This paper outlines the significant lessons learned from a partnering approach between a consultant and a central government service provider. The partnership was built on an ethos of knowledge share and transfer; it developed long-term relationships that continued after the end of the original programme. It is an example of how a partnering approach to a single project acted as a catalyst for the further development of each organisation. One of the significant factors involved is the people, their personal and professional relationships and their willingness to innovate at all times. The partnering ethos led to innovation in terms of amending the payment mechanism under the contract as originally procured, leading to potential incentives and disincentives based on performance measured using key performance indicators as advocated by the Egan report.
Infrastructure cost planning: a design-led approach
Authors: Saroop S. H. , Allopi D.
Published: August 2007

Minimum cost has become a critical performance criterion for most engineers in the provision of township infrastructure service schemes. Consultants spend very little time generating alternative project options, often presenting decision-makers with only a few poorly differentiated alternatives borrowed ad hoc from other projects. Infrastructure projects' costs are scrutinised more closely and with greater skill and accuracy as projects have become larger, more complex and more expensive; clients have also become more exacting in their requirements. These and other factors have compelled engineers to design with greater care and in more detail. This paper contributes to the underdeveloped area of cost planning and forecasting on infrastructure projects by maximising the opportunity for improving quality and reducing project costs at each stage in the design process. In times of ever-increasing costs, the majority of clients, globally, are insisting on projects being designed and executed to give maximum value for money. The cost planning model and its outputs represent a disciplined effort to produce fundamental decisions in shaping project costs. This will place a heavy burden on consultants to use clients' money in the most efficient way possible. The cost planning model attempts to relate design to cost so that, while taking full account of quality, utility and appearance, the cost is planned to be within the economic limit of expenditure.
L'importance de l'attitude ludique en ergothérapie avec une clientèle adulte
Authors: Guitard Paulette , Ferland Francine , Dutil Élisabeth
Published: August 2007

Description. Comme l'attitude ludique demeure peu documentée chez l'adulte, son potentiel thérapeutique est incertain. But et méthodologie. Une démarche qualitative mène à l'élaboration d'un modèle conceptuel de l'attitude ludique à l'âge adulte qui permettra de discuter de son utilisation possible en ergothérapie. Résultats. Le modèle identifie les sources d'influences et les conséquences de l'attitude ludique chez l'adulte. Les conséquences identifiées rejoignent à la fois la modalité privilégiée en ergothérapie, soit l'activité significative, et les objectifs d'intervention soit la capacité d'agir, la santé et le bien-être. Pour ces raisons, le modèle proposé présente un potentiel intéressant pour l'intervention ergothérapique. Conséquences pour la clinique. Ce modèle conceptuel présente une vision unique et innovatrice de l'attitude ludique à l'âge adulte qui ouvre une nouvelle voie pour l'activité significative. Il suggère que l'attitude ludique pourrait devenir un outil important en ergothérapie pour développer la capacité d'agir. Il propose ainsi une façon innovatrice d'aborder le client.
Recension des écrits sur la perception des intervenants et des clients à L'égard de l'approche client en psychiatrie
Authors: Goulet Claudine , Rousseau Jacqueline , Fortier Pierre
Published: August 2007

Description : Cet article présente une recension des écrits sur la question suivante : Selon les intervenants et les clients, l'approche des intervenants en psychiatrie est-elle centrée sur les besoins des clients? But : Comparer les perceptions des clients et des intervenants quant à l'utilisation de l'approche client et l'identification des besoins d'intervention en psychiatrie. Méthodologie : Les bases de données Medline, PsycInfo et CINAHL ont été consultées; huit études ont été retenues. Résultats : Intervenants et clients s'accordent sur le fait que l'approche client n'est pas priorisée en psychiatrie. Différents motifs sont amenés par les deux parties. Il existe peu d'accord intervenant-client quant aux besoins d'intervention. Plusieurs besoins des clients semblent non satisfaits (relations interpersonnelles, habiletés de vie autonome, activités productives, adaptation à la maladie, soins de santé). Conséquences pour la pratique : Les ergothérapeutes doivent centrer davantage leurs interventions sur le client en évaluant l'ensemble des besoins, en développant des services pour l'investissement d'activités sociales ou productives et en consultant les clients et les familles pour évaluer la qualité des services.
Computer Programming in Middle School: How Pairs Respond to Challenges
Authors: Denner Jill , Werner Linda
Published: August 2007

Many believe that girls lack the confidence and motivation to persist with computers when they face a challenge. In order to increase the number of girls and women in information technology careers, we need a better understanding of how they think about and solve problems while working on the computer. In this article, we describe a qualitative study of 126 middle school girls who designed and programmed computer games in an after-school and summer program. Using data from electronic notebooks, we describe how girls thought about the problems they had while programming their games and the strategies they used in their efforts to solve them. Audiotape transcripts were also coded to show how girls talk about challenges and the steps they take to address them when programming a game on the computer. The findings are interpreted in terms of how to promote information technology fluency starting in middle school.
Generating Topic Headings During Reading of Screen-Based Text Facilitates Learning of Structural Knowledge and Impairs Learning of Lower-Level Knowledge
Authors: Clariana Roy B. , Marker Anthony W.
Published: August 2007

This investigation considers the effects of learner-generated headings on memory. Participants ( N = 63) completed a computer-based lesson with or without learner-generated text topic headings. Posttests included a cued recall test of factual knowledge and a sorting task measure of structural knowledge. A significant disordinal interaction was observed with the no headings group performing better on the cued recall test and worse on the structural knowledge sorting task. In addition, a measure of structural knowledge using a list-wise rating task was field trialed. The two structural knowledge tasks were analyzed using a Pathfinder network scoring technique that measured both linear and nonlinear text subtopic organization. The sorting and rating tasks were differentially sensitive to participants' linear and nonlinear knowledge organization. Unexpectedly, the sorting and rating posttest tasks improved cued recall posttest scores. The implications of the results for measuring structural knowledge are considered and suggestions for further studies are presented.
Preservice Teachers' Abilities, Beliefs, and Intentions regarding Technology Integration
Authors: Anderson Susan E. , Maninger Robert M.
Published: August 2007

This study investigated changes in and factors related to students' technology-related abilities, beliefs, and intentions. Participants were 76 preservice teachers who responded to pre- and post-course surveys while taking an introductory educational technology course. Statistically significant changes were found in students' perceived abilities, self-efficacy beliefs, value beliefs, and intentions to use software in their future classrooms. Students' self-efficacy, value beliefs, and intentions were moderately correlated with each other. Abilities were correlated with self-efficacy and computer access. The best predictors of intentions were self-efficacy beliefs, gender, and value beliefs. These results strongly support the effectiveness of educational technology coursework in improving not just abilities, but also beliefs and intentions. They highlight the importance of relationships between preservice teachers' beliefs about technology integration and their potential use of technology in their future classrooms. The authors provide suggestions for enhancing preservice teachers' beliefs during technology coursework.
Microhardness and microstructure of deciduous enamel with different types of amelogenesis imperfecta
Authors: Pavlič Alenka , Škraba Polona , Kosec Ladislav , Petelin Milan , Alaluusua Satu
Published: August 2007

Amelogenesis imperfecta (AI) is an inherited tooth disorder with widely varying phenotypes. The aim of this study was to determine the microhardness and microstructure characteristics of the enamel in AI teeth. The AI phenotypes examined were hypoplastic (pitted and smooth form), hypomaturated, and hypocalcified. Six AI patients were diagnosed according to clinical characteristics. The microhardness of the enamel was measured on axial cuts of AI teeth acquired from the patients. The measurements were done on several sites from the enamel surface towards the dentine-enamel junction using the Vickers scale. Values of microhardness were compared to corresponding control teeth. The microstructure of AI enamel types was evaluated using scanning electron microscopy. The values of microhardness in pitted hypoplastic AI samples were, on average, lower compared to the control enamel and dropped markedly towards the dentine-enamel junction. The smooth hypoplastic enamel was not only extremely thin but also much softer than control enamel. The values for hypomaturated AI fluctuated, but the palatal sites were markedly softer than in the control tooth. Hypocalcified enamel was the softest, with values resembling those of dentin. Microstructural changes varied from altered orientation of enamel prisms in pitted hypoplastic AI to lack of normal prismatic structure and severe porosity in hypocalcified AI. The present results suggest different microhardness profiles and microstructures in each phenotype. Variations among phenotypes are expected with larger case selection in this genetically heterogeneous disease.
Cover Picture: Effect of Water Filling on the Electronic and Vibrational Resonances of Carbon Nanotubes: Characterizing Tube Opening by Raman Spectroscopy (Adv. Mater. 17/2007)
Authors: Wenseleers W. , Cambré S. , Čulin J. , Bouwen A. , Goovaerts E.
Published: August 2007

Closed (empty) and opened (water‐filled) single‐walled carbon nanotubes (SWNTs), such as the (12,1) SWNTs shown (foreground), can be clearly resolved in 2D Raman maps (background) of bile salt solubilized SWNTs in water, report Wim Wenseleers and co‐workers on p. 2274. While being of fundamental interest, this also provides a method to monitor tube opening/closing under various treatments (insets, left to right: as‐produced; mechanically treated; chemically treated; reclosed SWNTs by annealing).
Copper‐Catalyzed Enantioselective Conjugate Addition of Organometallic Reagents to Acyclic Dienones
Authors: Šebesta Radovan , Pizzuti M. Gabriella , Minnaard Adriaan J. , Feringa Ben L.
Published: August 2007

The enantioselective, copper/phosphoramidite‐catalyzed 1,4‐addition of dialkylzinc reagents to acyclic dienones is described. The products of this reaction, obtained with enantioselectivities of up to 95 %, can be further functionalized by a second conjugate addition, or employed in an enolate trapping, ring‐closing metathesis protocol.
Catalysis in Water: Aldol‐Type Reaction of Aldehydes and Imines with Ethyl Diazoacetate Catalyzed by Highly Basic Magnesium/Lanthanum Mixed Oxide
Authors: Kantam M. Lakshmi , Balasubrahmanyam V. , Kumar K. B. Shiva , Venkanna G. T. , Figueras F.
Published: August 2007

Magnesium/lanthanum mixed oxide is an effective heterogeneous catalyst for aldol‐type condensation of aldehydes and imines with ethyl diazoacetate (EDA) at room temperature in water to afford corresponding β‐hydroxy‐α‐diazo carbonyl compounds and β‐amino‐α‐diazo carbonyl compounds in good yields. The catalyst is recovered and reused for several cycles with consistent activity.
Regioselective Hydrolysis of Different Peracetylated β‐Monosaccharides by Immobilized Lipases from Different Sources. Key Role of The Immobilization
Authors: Palomo Jose M. , Filice Marco , Fernandez‐Lafuente Roberto , Terreni Marco , Guisan Jose M.
Published: August 2007

The effect of the immobilization strategy on the activity, specificity and regioselectivity of three different lipases [those from Thermomyces lanuginose (TLL), Aspergillus niger (ANL) and Candida antarctica B (CAL‐B)] in the hydrolysis of peracetylated β‐monosaccharides has been evaluated. Three very different immobilization strategies were utilized, covalent attachment, anionic exchange and interfacial activation on a hydrophobic support. The octyl‐TLL immobilized preparation was the most efficient biocatalyst in the hydrolysis of 1,2,3,4,6‐penta‐O‐acetyl‐β‐D‐galactopyranose, producing specifically 6‐hydroxy‐1,2,3,4‐tetra‐O‐acetyl‐β‐D‐galactopyranose in 95 % overall yield, whereas the CNBr‐TLL preparation was 48 times slower and regioselective towards the anomeric position, producing the 1‐hydroxy derivative in 70 % yield. The PEI‐TLL immobilized preparation was the most efficient catalyzing the hydrolysis of 1,2,3,4,6‐penta‐O‐acetyl‐β‐D‐glucopyranose, permitting us to obtain up to 70 % of the 6‐hydroxy product. In the hydrolysis of 2‐acetamido‐2‐deoxy‐1,3,4,6‐tetra‐O‐acetyl‐β‐D‐glucopyranose, the octyl‐CALB preparation was not selective at all for the production of monohydroxy products whereas when CAL‐B was immobilized on PEI‐agarose, the enzyme was highly specific and regioselective producing the 6‐hydroxy‐2‐acetamido‐2‐deoxy‐1,3,4‐tri‐O‐acetyl‐β‐D‐glucopyranose in 70 % yield.
Asymmetric Baeyer–Villiger Biooxidation of α‐Substituted Cyanocyclohexanones: Influence of the Substituent Length on Regio‐ and Enantioselectivity
Authors: Berezina Nathalie , Kozma Erika , Furstoss Roland , Alphand Véronique
Published: August 2007

Cells of Escherichia coli expressing cyclohexanone monooxygenase catalyzed a highly enantioselective Baeyer–Villiger oxidation of α‐substituted cyanocyclohexanones, leading to the corresponding enantiopure caprolactones (ees >97 %). Classical kinetic resolution and regiodivergent parallel kinetic resolution patterns were observed, depending on the length of the linear chain at the alpha position. Regioselectivity was compared with that of chemical BV oxidations. Cells revealed an outstanding stability since 50 % of the specific BV activity was retained after 42 days of storage, which facilitates their use in biotransformations.
Chiral Amine Thiourea‐Promoted Enantioselective Domino Michael‐Aldol Reactions between 2‐Mercaptobenzaldehydes and Maleimides
Authors: Zu Liansuo , Xie Hexin , Li Hao , Wang Jian , Jiang Wei , Wang Wei
Published: August 2007

An organocatalytic, enantioselective domino Michael‐aldol reaction of 2‐mercaptobenzaldehydes with maleimides has been developed. The process, catalyzed by a bifunctional chiral amine thiourea via a hydrogen‐bonding mediated activation mechanism using as low as 1 mol % catalyst loading, affords versatile succinimide‐containing benzothiopyrans with the generation of 3 stereogenic centers in one single operation.
Tandem Metal‐ and Organocatalysis in Sequential Hydroformylation and Enantioselective Aldol Reactions
Authors: Chercheja Serghei , Eilbracht Peter
Published: August 2007

Metal‐catalysed hydroformylation is successfully combined with organocatalysed stereoselective aldol addition into a tandem reaction sequence. This novel type of “tandem catalysis” allows access to complex molecular systems with high levels of enantioselectivity, using simple starting materials and an amino acid as the chiral catalyst.
Domino Hydroformylation/Enantioselective Cross‐Aldol Addition
Authors: Abillard Olivier , Breit Bernhard
Published: August 2007

A domino hydroformylation/enantioselective cross‐aldol reaction sequence is reported. Starting from simple alkenes enantiomerically pure aldol addition products, which represent valuable building blocks for polypropionate construction, can be obtained in a one‐pot operation.
Efficient Acid‐Catalyzed Hydrolysis of Cellulose in Ionic Liquid
Authors: Li Changzhi , Zhao Zongbao K.
Published: August 2007

A novel method for cellulose hydrolysis catalyzed by mineral acids in the ionic liquid 1‐butyl‐3‐methylimidazolium chloride ([C4mim]Cl) has been developed that facilitates the hydrolysis of cellulose with dramatically accelerated reaction rates at 100 °C under atmospheric pressure and without pretreatment.
Temperature‐induced morphology control in the polymer‐foaming process
Authors: Jacobs L. J. M. , Kemmere M. F. , Keurentjes J. T. F. , Mantelis Ch. A. , Meyer Th.
Published: August 2007

Supercritical carbon dioxide (scCO2) is a promising foaming agent for the production of polymeric foams, representing an environmentally friendly alternative for the foaming agents currently used. During the expansion phase of the scCO2‐foaming process, temperature plays an essential role. This study focuses on relating the effects of temperature and pressure profiles on the foaming process and the resulting foam morphology. Therefore, several experiments have been performed in a high pressure reaction calorimeter (RC1e) that can be set to three different modes: isothermal, adiabatic, and isoperibolic. It has been observed that the foaming could be divided into four stages: nucleation, slow cell growth, fast cell growth, and shrinkage. The degree of shrinking that occurs is for a great deal dependent on the exposure to higher temperatures at the end of the foaming process. Since shrinkage does not occur in the adiabatic mode, this mode gives the best control on the foam morphology. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Mutations and polymorphisms in hemoglobin genes and the risk of pulmonary hypertension and death in sickle cell disease
Authors: Taylor James G. , Ackah Diana , Cobb Crystal , Orr Nick , Percy Melanie J. , Sachdev Vandana , Machado Roberto , Castro Oswaldo , Kato Gregory J. , Chanock Stephen J. , Gladwin Mark T.
Published: August 2007

Pulmonary hypertension is a common complication of sickle cell disease (SCD) and a risk factor for early death. Hemolysis may participate in its pathogenesis by limiting nitric oxide (NO) bioavailability and producing vasculopathy. We hypothesized that hemoglobin mutations that diminish hemolysis in SCD would influence pulmonary hypertension susceptibility. Surprisingly, coincident α‐thalassemia (Odds Ratio [OR] = 0.95, 95% CI = 0.46–1.94, P = NS) was not associated with pulmonary hypertension susceptibility in homozygous SCD. However, pulmonary hypertension cases were less likely to have hemoglobin SC (OR = 0.18, 95% confidence interval [CI] = 0.06–0.51, P = 0.0005) or Sβ+ thalassemia (OR = 0.25, 95% CI = 0.06–1.16, P = 0.10). These compound heterozygotes may be protected from pulmonary hypertension because of reduced levels of intravascular hemolysis, but develop this complication at a lower rate possibly due to the presence of non‐hemolytic risk factors such as renal dysfunction, iron overload and advancing age. Despite this protective association, patients with SC who did develop pulmonary hypertension remained at significant risk for death during 49 months of follow‐up (Hazard Ratio = 8.20, P = 0.0057). Am. J. Hematol., 2008. Published 2007 Wiley‐Liss, Inc.
UGT2B7 promoter variant −840G>A contributes to the variability in hepatic clearance of morphine in patients with sickle cell disease
Authors: Darbari Deepika S. , van Schaik Ron H.N. , Capparelli Edmund V. , Rana Sohail , McCarter Robert , van den Anker John
Published: August 2007

The purpose of the study was to determine if UDP‐glucuronosyltransferase (UGT) 2B7 allelic variants encoding for UGT2B7, primary enzyme responsible for morphine glucuronidation contribute to the variability in the hepatic clearance of morphine in sickle cell disease (SCD). Twenty‐four hour PK study of morphine and UGT2B7 variants genotyping was performed in 20 SCD patients in a steady state of health. Presence of the −840G allele (GG and GA) was associated with lower morphine metabolites/morphine AUC ratio compared with AA genotype (1.8 ± 0.5 vs. 3.0 ± 1.8 for M6G/M and 10.1 ± 2.7 vs. 15.7 ± 9.4 for M3G/M) (P = 0.03). Presence of UGT2B7 −840G allele is associated with significantly reduced glucuronidation of morphine and thus contributes to the variability in hepatic clearance of morphine in SCD. Am. J. Hematol., 2008. © 2007 Wiley‐Liss, Inc.
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

Screening 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

The 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

A 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

Effect 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

Fibrillin 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

Das 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

Ingenieurbauwerke, 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

We 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

In 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

We 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

The 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

The 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

Candida 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

Batch 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

The 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

The 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

Political 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.