bluuebunny/crossref_metadata_2025 huggingface dataset:
Association Between Polymorphisms in the β2‐adrenoceptor Gene and Migraine in Women
Authors: Schürks Markus , Kurth Tobias , Ridker Paul M , Buring Julie E. , Zee Robert Y.L.
Published: July 2008

Objective.—To investigate the role of three common polymorphisms in the β2‐adrenoceptor gene in migraine.

Background.—Migraine has been associated with increased risk of cardiovascular disease and asthma in which β2‐adrenoceptors play an important role; β‐adrenoceptor antagonists are used in migraine prevention. However, the role of variants in the β2‐adrenoceptor gene in migraine is unclear.

Methods.—Association study among 23,753 white women, participating in the Women's Health Study, for whom we had information on migraine at baseline and genotype status of the polymorphisms rs1042713 (Gly16Arg), rs1042714 (Gln27Glu), rs1800888 (Thr164Ile). Migraine was self‐reported and we distinguished between any history of migraine, active migraine with and without aura, and prior migraine (history of migraine but not active migraine) in our analyses.

Results.—At baseline 4339 women reported any history of migraine. Of these, 3041 had active migraine (1221 migraine with aura, 1820 migraine without aura) and 1298 prior migraine. No migraine was reported by 19,414 women. Genotype‐ and haplotype‐based analyses did not show an association of any of the gene variants tested with any history of migraine. The multivariable‐adjusted odds ratios (ORs) (95% confidence intervals) for any history of migraine in the additive model were 1.0 (0.96‐1.05) for rs1042713, 1.0 (0.95‐1.05) for rs1042714, and 0.84 (0.68‐1.05) for rs1800888. In the haplotype analysis the ORs ranged from 0.83 (0.67‐1.03) to 1.01 (0.94‐1.07) with Gly16‐Glu27‐Thr164 as the reference. We also did not find associations in the genotype‐ and haplotype‐based analyses within migraine‐specific subgroups.

Conclusions.—Our results do not support a role of 3 investigated polymorphisms in the β2‐adrenoceptor gene in migraine pathophysiology.
Intra‐Arterial Milrinone for Reversible Cerebral Vasoconstriction Syndrome
Authors: Bouchard Manon , Verreault Steve , Gariépy Jean‐Luc , Dupré Nicolas
Published: July 2008

Reversible cerebral vasoconstriction syndrome (RCVS) usually presents with recurrent thunderclap headaches and is characterized by multifocal and reversible vasoconstriction of cerebral arteries that can sometimes evolve to severe cerebral ischemia and stroke. We describe the case of a patient who presented with a clinically typical RCVS and developed focal neurological symptoms and signs despite oral treatment with calcium channel blockers. Within hours of neurological deterioration, she was treated with intra‐arterial milrinone, a phosphodiesterase inhibitor, which resulted in a rapid and sustained neurological improvement.
Student Perceptions of Social Loafing in Undergraduate Business Classroom Teams
Authors: Jassawalla Avan R. , Malshe Avinash , Sashittal Hemant
Published: July 2008

There is a rich body of research devoted to the causes and remedies of social loafing in workplace teams. However, the social loafing phenomenon remains underinvestigated from the perspective of students in undergraduate business classroom teams. In particular, how they define and respond to loafing remains unknown. This article reports findings from a two‐stage study that shows social loafing as a more complex construct than current conceptions suggest. Moreover, students avoid confronting loafers and prefer to have instructors administer postpriori justice based on their self‐report of individual contributions. Based on the findings and recent writings, the article speculates on the causes of these student responses to social loafing in classroom teams.
Capturing Flow in the Business Classroom
Authors: Guo Yi Maggie , Ro Young K.
Published: July 2008

This study focuses on the flow experience in business education. Flow experience, characterized by concentration, control, and enjoyment, can lead to better learning outcomes. Leading preconditions of flow include the balance of challenge and skill, feedback, and goal clarity. Other situational factors affect the flow experience through the mediating effects of these three factors. In this article, we extend an existing framework linking flow and learning. Using the model as a guide, we start our research effort of flow in business education by conducting a field survey of student learning experience in terms of flow and influential factors. Data were collected using business students taking an introductory Operations Management course. The analysis reveals that flow does exist in classroom learning. Its key dimensions are concentration, sense of control, and enjoyment. The more important leading factor is having clear feedback. Characteristics of both the instructor and students play a role in the flow experience of students during lecture. It is evident that flow theory offers a useful framework for business education research. Suggestions for future research are made.
The Use of Student Consulting Projects as an Active Learning Pedagogy: A Case Study in a Production/Operations Management Course
Authors: Heriot Kirk C. , Cook Ron , Jones Rita C. , Simpson Leo
Published: July 2008

Active learning has attracted considerable attention in higher education in response to concerns about how and what students are learning. There are many different forms of active learning, yet most of them are classroom based. We propose an alternative to active learning in the classroom through active learning outside of the classroom in the form of student consulting projects. While the literature on student consulting has largely focused on projects to assist small business owners, this research demonstrates the potential for using student‐consulting projects in the Production/Operations Management course. We use a case study to describe the use of a student‐consulting project as an alternative to the other types of active learning described in the Operations Management education literature.
Functional Regression Analysis of Fluorescence Curves
Authors: Ritz Christian , Streibig Jens C.
Published: July 2008

SummaryFluorescence curves are useful for monitoring changes in photosynthesis activity. Various summary measures have been used to quantify differences among fluorescence curves corresponding to different treatments, but these approaches may forfeit valuable information. As each individual fluorescence curve is a functional observation, it is natural to consider a functional regression model. The proposed model consists of a nonparametric component capturing the general form of the curves and a semiparametric component describing the differences among treatments and allowing comparisons of treatments. Several graphical model‐checking approaches are introduced. Both approximate, asymptotic confidence intervals as well as simulation‐based confidence intervals are available. Analysis of data from a crop experiment using the proposed model shows that the salient features in the fluorescence curves are captured adequately. The proposed functional regression model is useful for analysis of high throughput fluorescence curve data from regular monitoring or screening of plant growth.
Phase Transition, Piezoelectric Properties, and Thermal Stability of (1−x−y)BiScO3–yBiGaO3–xPbTiO3 Ceramics
Authors: Jiang Yihang , Qin Baoquan , Zhao Yi , Jiang Yuzhi , Shi Wei , Li Qishou , Xiao Dingquan , Zhu Jianguo
Published: July 2008

(1−x−y)BiScO3–yBiGaO3–xPbTiO3 (BGSPTx/y) piezoelectric ceramics were synthesized using the conventional oxide process. The phase diagram around the ternary morphotropic phase boundary of BGSPTx/y has been determined. It was found that BGSPT0.55/0.19 ceramics possessed a high Curie temperature (TC) of about 502°C, while maintaining their rather high piezoelectric properties of d33=152 pC/N and d31=−60 pC/N. In addition, BGSPT0.62/0.15 ceramics showed good resistance to thermal depoling up to about 480°C. The excellent thermal stability of BGSPTx/y may allow this material to be used as stable piezoelectric sensors for extreme high‐temperature environments.
Justice at a Price: Regulation and Alienation in the Global Economy
Authors: Reichman Daniel
Published: July 2008

This article examines the normative principles that underlie efforts to regulate the global coffee market at different points in the global division of labor. I focus on three forms of regulation: local violence against coffee farmers in Honduras, fair trade consumerism, and international regulatory treaties. By comparing the local politics of Honduran coffee production to global forms of consumer activism, I bring contemporary debates about economic justice under a single analytic lens. I suggest that systematic changes in the relationship between states and nations have led alienated citizens to develop new forms of regulation outside the boundaries of the state, and that coffee frequently serves as a metaphor through which people come to terms with their place in the global economy. This metaphor ultimately rests on an alienated representation of the global system that limits the political potential of these regulatory strategies.
Modeling discrete choices with augmented perception hurdles
Authors: Hu Wuyang
Published: July 2008

Through creating latent perception hurdles associated with each attribute considered in a stated conjoint experiment, this article describes a model that augments the conventional approach by utilizing the importance ratings provided by respondents prior to the discrete choice stage. The resulting perception hurdle logit (PHL) model has both advantages and disadvantages compared to the conditional logit (CL) and mixed logit models. Although the proposed model may not have the best within‐sample fit, it outperforms the other two models in predicting choices in a hold out sample. In addition, the proposed model is also used to reveal that depending on their own characteristics and the process of the survey, respondents may employ an array of different decision strategies.
The effect of non‐surgical periodontal therapy on peroxidase activity in diabetic patients: a case–control pilot study
Authors: Gonçalves Daniela , Correa Fernanda Oliveira Bello , Khalil Najeh Maissar , De Faria Oliveira Olga Maria Mascarenhas , Orrico Silvana Regina Perez
Published: July 2008

Objective: To evaluate the effect of periodontal therapy on clinical parameters as well as on total salivary peroxidase (TSP) activity and myeloperoxidase (MPO) activity in the gingival crevicular fluid (GCF) of patients with type 2 diabetes mellitus (DM2) and of systemically healthy individuals.

Material and Methods: Twenty DM2 subjects with inadequate metabolic control (test group) and 20 systemically healthy individuals (control group), both groups with chronic periodontitis, were enrolled. Periodontal clinical parameters, namely periodontal probing depth (PD), clinical attachment level (CAL), visible plaque index (VPI), bleeding on probing (BOP), gingival bleeding index (GBI) and presence of suppuration (SUP), as well as TSP activity and GCF MPO activity, were assessed before and 3 months after non‐surgical periodontal therapy.

Results: At baseline and 3 months post‐treatment, the test group presented a higher percentage of sites with VPI and BOP (p<0.01). MPO activity in the GCF presented lower values (p<0.05) for the test group at both baseline and the post‐treatment period. The periodontal treatment resulted in a significant improvement of most clinical and enzymatic parameters for both groups (p<0.05).

Conclusions: In both groups, the periodontal therapy was effective in improving most clinical parameters and in reducing salivary and GCF enzymatic activity. The diabetic individuals presented lower MPO activity in the GCF.
Structural and functional insights into Erwinia carotovora l‐asparaginase
Authors: Papageorgiou Anastassios C. , Posypanova Galina A. , Andersson Charlotta S. , Sokolov Nikolay N. , Krasotkina Julya
Published: July 2008

Bacterial l‐asparaginases are enzymes that catalyze the hydrolysis of l‐asparagine to aspartic acid. For the past 30 years, these enzymes have been used as therapeutic agents in the treatment of acute childhood lymphoblastic leukemia. Their intrinsic low‐rate glutaminase activity, however, causes serious side‐effects, including neurotoxicity, hepatitis, coagulopathy, and other dysfunctions. Erwinia carotovora asparaginase shows decreased glutaminase activity, so it is believed to have fewer side‐effects in leukemia therapy. To gain detailed insights into the properties of E. carotovora asparaginase, combined crystallographic, thermal stability and cytotoxic experiments were performed. The crystal structure of E. carotovoral‐asparaginase in the presence of l‐Asp was determined at 2.5 Å resolution and refined to an Rcryst of 19.2 (Rfree = 26.6%) with good stereochemistry. Cytotoxicity measurements revealed that E. carotovora asparaginase is 30 times less toxic than the Escherichia coli enzyme against human leukemia cell lines. Moreover, denaturing experiments showed that E. carotovora asparaginase has decreased thermodynamic stability as compared to the E. coli enzyme and is rapidly inactivated in the presence of urea. On the basis of these results, we propose that E. carotovora asparaginase has limited potential as an antileukemic drug, despite its promising low glutaminase activity. Our analysis may be applicable to the therapeutic evaluation of other asparaginases as well.
Use of chemical tracers to assess diet and persistent organic pollutants in Antarctic Type C killer whales
Authors: Krahn Margaret M. , Pitman Robert L. , Burrows Douglas G. , Herman David P. , Pearce Ronald W.
Published: July 2008

Abstract

Measuring chemical tracers in tissues of marine predators provides insight into the prey consumed and the predator's contaminant exposure. In this study, samples from Type C killer whales (Orcinus orca) biopsied in Antarctica were analyzed for chemical tracers (i.e., stable isotopes of carbon and nitrogen, fatty acids, and persistent organic pollutants [POPs]). Profiles of these individual tracers were very different from those of killer whale populations that have been studied in the eastern North and eastern Tropical Pacific. For example, δ13C and δ15N stable isotope values and most POP concentrations were significantly lower in the Antarctic population. In addition, multivariate statistical analyses of both fatty acid and POP profiles found distinctly different patterns for Antarctic Type C whales compared to those from whales in the other populations. Similar assays were conducted on four species of Antarctic marine fish considered potential prey for Type C killer whales. Results were consistent with a diet of fish for Type C whales, but other species (e.g., low trophic‐level marine mammals or penguins) could not be eliminated as supplemental prey.
Making Sense of Feminist Theology Today
Authors: Schneider Laurel C. , Trentaz Cassie J. E.
Published: July 2008

Feminist theology today denotes a widening field of scholarship that shares historic, pragmatic concerns about gender justice in diverse cultural and racial contexts, but that increasingly differs in approach. In this essay, we discuss internal, creative challenges surfacing in (largely Christian) feminist theologies and review the historical social movements that have shaped them up to the present. Theologians who use race, queer, and postcolonial theory to assert the co‐constituting dynamics of gender with race, class, sexuality, nationality, and religion are muddying the waters of older feminisms that focused exclusively on gender, rendering the future of feminist theologies more ambiguous, broad‐reaching, and fluid.
Common Pitfalls of Beginning Therapists Utilizing Enactments
Authors: Butler Mark H. , Davis Sean D. , Seedall Ryan B.
Published: July 2008

Empirical data, clinical observation, and theoretical rationales support use of enactments as a fundamental mechanism of change in relationship therapies. Yet beginning therapists may lack an adequate conceptual framework and operational training essential to effectively utilize enactments. Inadequate training may contribute to ineffective execution, and in turn to negative results, which could lead to abandonment of enactments. This study sought to identify proficiencies and nonproficiencies of beginning therapists in conducting enactments. Twenty beginning therapists from three Commission on Accreditation for Marriage and Family Therapy Education (COAMFTE)‐accredited programs were briefly trained in an indirect therapy style that incorporates enactments. Twenty‐six therapist enactments were coded using a comprehensive observational measure designed to assess proficiencies and nonproficiencies in executing enactment phases, component tasks, and subcomponent operations. Results suggest that beginning therapists struggle with numerous clinical operations conceptually linked to the successful engagement of relationships in marriage and family therapy. In light of these findings, specific recommendations for additional enactment training in COAMFTE‐accredited programs are offered.
Examining the Impact of Gender, Race/Ethnicity, and Family Factors on Mental Health Issues in a Sample of Court‐Involved Youth
Authors: Gavazzi Stephen M. , Bostic Jennifer M. , Lim Ji‐Young , Yarcheck Courtney M.
Published: July 2008

Faced with anywhere between one half and two thirds of its youth having a diagnosable mental illness, the identification and treatment of mental health concerns is a critically important endeavor for professionals working with youth who have contact with the juvenile justice system. In addition, the literature suggests that factors related to both the family and to the gender of the adolescent must be incorporated into any approach to assessment and intervention within this special population. Further, prior work that has documented the interaction of gender and family issues with adolescent race/ethnicity warrants further empirical attention, as does the intermediary role that the family may play in the development of both internalizing and externalizing behaviors. The present study extends this literature by examining factors related to gender, race/ethnicity, family factors, and mental health issues in a sample of 2,549 Caucasian and African American youth coming to the attention of juvenile courts. Multivariate analysis of variance results indicated significant main effects for gender and race/ethnicity, as well as a significant gender × race/ethnicity interaction for the family and externalizing variables. A multiple group structural equation modeling procedure was employed in order to test the hypothesis that family environment mediates the relationship between gender and mental health problems, as well as to test for potential differences in these relationships as a function of race/ethnicity. Results indicated support for the mediation model in the sample of African American youth but not in the sample of Caucasian youth.
Two flavonoids extracts from Glycyrrhizae radix inhibit in vitro hepatitis C virus replication
Authors: Sekine‐Osajima Yuko , Sakamoto Naoya , Nakagawa Mina , Itsui Yasuhiro , Tasaka Megumi , Nishimura‐Sakurai Yuki , Chen Cheng‐Hsin , Suda Goki , Mishima Kako , Onuki Yuko , Yamamoto Machi , Maekawa Shinya , Enomoto Nobuyuki , Kanai Takanori , Tsuchiya Kiichiro , Watanabe Mamoru
Published: July 2008

Aim:  Traditional herbal medicines have been used for several thousand years in China and other Asian countries. In this study we screened herbal drugs and their purified compounds, using the Feo replicon system, to determine their effects on in vitro HCV replication.

Methods:  We screened herbal drugs and their purified extracts for the activities to suppress hepatitis C virus (HCV) replication using an HCV replicon system that expressed chimeric firefly luciferase reporter and neomycin phosphotransferase (Feo) genes. We tested extracts and 13 purified compounds from the following herbs: Glycyrrhizae radix; Rehmanniae radix; Paeoniae radix; Artemisiae capillari spica; and Rhei rhizoma.

Results:  The HCV replication was significantly and dose‐dependently suppressed by two purified compounds, isoliquiritigenin and glycycoumarin, which were from Glycyrrhizae radix. Dose‐effect analyses showed that 50% effective concentrations were 6.2 ± 1.0 µg/mL and 15.5 ± 0.8 µg/mL for isoliquiritigenin and glycycoumarin, respectively. The MTS assay did not show any effect on cell growth and viability at these effective concentrations, indicating that the effects of the two compounds were specific to HCV replication. These two compounds did not affect the HCV IRES‐dependent translation nor did they show synergistic action with interferon‐alpha.

Conclusion:  Two purified herbal extracts, isoliquiritigenin and glycycoumarin, specifically suppressed in vitro HCV replication. Further elucidation of their mechanisms of action and evaluation of in vivo effects and safety might constitute a new anti‐HCV therapeutics.
A Study on Warm Hydroforming of Al and Mg Sheet Materials: Mechanism and Proper Temperature Conditions
Authors: Choi Ho , Koç Muammer , Ni Jun
Published: July 2008

Hydroforming of lightweight materials at elevated temperature is a relatively new process with promises of increased formability at low internal pressure levels. In this study, the mechanism of warm hydroforming processes is presented in terms of its formability by comparison with warm forming, and cold hydroforming processes. Additionally, a strategy is proposed to control process parameters, such as temperature, hydraulic pressure, blank holder force, and forming speed. As a part of this strategy, the proper temperature condition is determined by adaptive-isothermal finite element analysis (FEA) and a design of experiment (DOE) approach. The adaptive-isothermal FEA determines the temperature levels of the blank material, which is selectively heated, by checking position of the blank material and adopting temperature level of the neighboring tooling. The proposed adaptive-isothermal FEA/DOE approach leads to the optimal temperature condition in a warm hydroforming system accurately and rapidly as opposed to costly and lengthy experimental trial and errors and/or fully coupled thermo-mechanical simulations. Other process parameters are also optimized in a continued study (Choi et al., 2007, “Determination of Optimal Loading Profiles in Warm Hydroforming of Lightweight Materials,” J. Mater. Process. Techn., 190(1–3), pp. 230–242.).
The Mode III Elastic Stress Distribution Near the Root of a Deep Sharp Notch With a Parabolic Root Profile
Authors: Smith E.
Published: July 2008

In developing a fracture initiation methodology for blunt notches, the basic starting point is the elastic stress distribution immediately ahead of a notch root. Earlier work for Mode III deformation of a two-dimensional blunt notch has shown that the shear stress immediately ahead of the notch root (i.e. at a distance small compared with the notch root radius of curvature) is dependent on the peak stress and notch root radius, but is independent of the notch shape and the loading characteristics. However there are many situations, i.e. with sharp notches, where we are interested in the stress at a distance that is not necessarily small compared with the notch root radius. Thus this paper shows that with a notch that has a parabolic root profile, when this distance and the notch root radius are both small compared with the notch depth, then the stress at this distance is again dependent on the peak stress and notch root radius, but is independent of the notch shape away from the root and the loading characteristics.
Elastic-Plastic-Creep Cyclic Loading of Structures
Authors: Eslami M. R. , Mahbadi H.
Published: July 2008

In this article, cyclic loading results of structures, such as cylindrical and spherical vessels are investigated. The structure’s material is assumed to be isotropic and homogeneous and obey a nonlinear strain hardening law in the plastic range. Two general plasticity theories, namely the isotropic and kinematic hardening theories with the von Mises associated flow rules are used to evaluate the cyclic results of these structures under various types of mechanical and thermal loads. Prager and Armstrong-Frederick kinematic hardening models are used to simulate the transformation of the yield surface in the stress space, due to imposed loads. A new iterative method is proposed and used to analyze the structural behavior under cyclic loading conditions. The results are verified with the known data given in the literature.
Experimental Program for Investigating the Influence of Cladding Defects on Burst Pressure
Authors: Yin Shengjun (Sean) , Bass B. Richard , McAfee Wallace J. , Williams Paul T.
Published: July 2008

An experimental program was conducted by the Heavy-Section Steel Technology Program at the Oak Ridge National Laboratory (ORNL) to evaluate the structural significance of defects found in the unbacked cladding of the Davis-Besse vessel head. ORNL conducted total 13 clad burst tests with unflawed/flawed specimens. Failure pressure data from those tests indicated a high degree of repeatability for the tests performed in the clad burst program. Unflawed clad burst specimens failed around the full perimeter of the disk from plastic instability; an analytical model for plastic collapse was shown to adequately predict those results. The flawed specimens tested in the program failed by ductile tearing of the notch defect through the clad layer. Analytical interpretations that utilized 3-D finite element models of the clad burst specimens were performed for all tests. Fractographic studies were performed on failed defects in the flawed burst specimens to verify the ductile mode of failure. Comparisons of computed results from 3-D finite element models with measured gage displacement data (i.e., center-point deflection and CMOD) indicated reasonably good agreement up to the region of instability. For tests instrumented with the CMOD gage, good agreement between calculated and measured CMOD data up to the onset of instability implies that ductile tearing initiated near the maximum load and (with a small increase in load) rapidly progressed through the clad layer to produce failure of the specimen.
The Influence of Crystallographic Orientations of Grains on Microstructurally Small Cracks Using Crystal Plasticity and Random Grain Structure
Authors: Simonovski I. , Cizelj L.
Published: July 2008

A plane-strain finite element crystal plasticity model of microstructurally small stationary crack emanating at a surface grain in a 316L stainless steel is proposed. The model consisting of 212 randomly shaped, sized and oriented grains is loaded monotonically in uniaxial tension to a maximum load of 1.12Rp0.2 (280 MPa). The influence that a random grain structure imposes on a Stage I crack is assessed by calculating the crack tip opening (CTOD) and sliding displacements (CTSD), considering also different crystallographic orientations. It is shown that certain crystallographic orientations result in a cluster of soft grains around the crack-containing grain. In these cases the crack tip can become apart of the localized strain, resulting in a large CTOD value. This effect, resulting from the overall grain orientations and sizes, can have a greater impact on the CTOD than the local grain orientation. On the other hand, when a localized soft response is formed away from the crack, the localized strain does not affect the crack tip directly, resulting in a small CTOD value. The resulting difference in CTOD can be up to a factor of 4, depending upon the crystallographic set. Grains as far as 6xCracklength significantly influence that crack tip parameters. It was also found the a larger crack-containing grain tends to increase the CTOD.
Basic Study on Shock Loading of Cryogenic Pressure Vessel and Piping
Authors: Watanabe Toshiaki , Otsuka Masahiko , Iyama Hirofumi , Itoh Shigeru
Published: July 2008

In recent years, the use of cryogenic fluids as a coolant has been increasing because of the industrial development of low temperature technology. Therefore, the use of the cryogenic pressure vessel and piping become general. LNG-tank, LN2, O2-tank at food factory and medical facilities are given for example. The safety of these pressure containers becomes important all the more. Thermal insulation of these cryogenic vessel and piping is usually carried out by using evacuation. In the cryogenic pressure vessel and piping, reducing the thermal insulation of that by initial small damage, leads to an internal pressure rise and occurring of flashing, and causing secondary crush of pressure vessel and piping also. Then, we conducted experiments with shock loading of commercial tanks and numerical simulation of shock loaded the double wall that contain vacuum layer. When thinking about safety aspects, it is important to consider about the spread of the shock wave in the double wall containing the vacuum layer.
Effect of Circumferential Location of Local Wall Thinning Defect on the Collapse Moment of Elbow
Authors: Kim Jin Weon , Na Yeon Soo , Park Chi Yong
Published: July 2008

Local wall-thinning due to flow-accelerated corrosion is one of the degradation mechanisms of carbon steel piping in nuclear power plant (NPP). It is a main concern in carbon steel piping systems in terms of the safety and operability of the NPP. Recently, the integrity of piping components containing local wall-thinning has become more important for maintaining the reliability of a nuclear piping system, and has been the subject of several studies. However, although wall-thinning in pipe bends and elbows has been frequently reported, its effect on the integrity of pipe bends and elbows has not yet been systematically investigated. Thus, the purpose of this study was to investigate the effect of the circumferential location of a local wall-thinning defect on the collapse behavior of an elbow. For this purpose, the present study used three-dimensional finite element analyses on a 90-degree elbow containing local wall-thinning at the crown of the bend region and evaluated the collapse moment of the wall-thinned elbow under various thinning geometries and loading conditions. The combined internal pressure and bending loads were considered as an applied load. Internal pressure of 0∼20 MPa and both closing-and opening-mode bending were applied. The results of the analyses showed that a reduction in the collapse moment of the elbow due to local wall-thinning was more significant when a defect was located at the crown than when a defect was located at the intrados and extrados. Also, the effect of the internal pressure on the collapse moment depended on the circumferential location of the thinning defect and mode of the bending load.
Creep-Fatigue Properties for Repair Welded Joint
Authors: Nonaka Isamu , Kubushiro Keiji , Ito Takuya , Takagi Yoshio
Published: July 2008

Repair welding has been performed when damage has been detected in aged power boiler piping. Discontinuity of deformation ability occurs between the new weld metal and degraded used material in the repair welded joint. Therefore creep-fatigue properties become important under displacement controlled piping system loading. Partial repair welded joint specimen and full repair weld joint specimen were made using the retired 2.25Cr-1Mo steel main steam header. In order to clarify the creep-fatigue properties for two kinds of repair welded joint specimens, fatigue tests under 0.7% strain range with 60min tensile strain dwell were performed at 600C. Both kinds of specimens were necked and fractured at the heat affected zone of welded joint due to the axial strain concentration and ratcheting at heat affected zone. The creep-fatigue life of partial repair weld joint specimen was about half of that of full repair weld joint specimen. This may be due to the low creep-fatigue resistance of the heat affected zone for partial repair welded joint specimen.
A 3-D Model for Evaluating the Residual Stress Field Due to Swage Autofrettage
Authors: Perry J. , Perl M.
Published: July 2008

In order to maximize the performance of modern gun barrels in terms of strength-to-weight ratio and total fatigue life, favorable compressive residual stresses are introduced to the inner portion of the barrel, commonly by the autofrettage process. There are two major autofrettage processes for overstraining the tube: the hydrostatic, and the swage. There are several theoretical solutions for hydrostatic autofrettage, based on Lame´’s solution and the von Mises or Tresca yield criteria. The residual stress field due to hydraulic autofrettage is treated as an axisymetric, two-dimensional problem solved in terms of the radial displacement solely. Once the Bauschinger effect was included in these models they yield very realistic results. Unlike in the case of hydraulic autofrettage, swage autofrettage needs to be modeled by a three-dimensional model. The present analysis suggests a new 3-D axisymmetric model for solving the residual stress field due to swage autofrettage in terms of both the radial and the axial displacements. The axisymetric equilibrium equations are approximated by finite differences and solved then by Gauss-Seidel method. Using the new computer code the stresses, the strains, the displacements and the forces are determined. A full-scale instrumented swage autofrettage test was conducted and the numerical results were validated against the experimental findings. The calculated strains, the permanent bore enlargement, and the mandrel pushing force were found to be in very good agreement with the measured values.
Ductile Failure Analyses for API X65 Pipes Based on Local Failure Criteria
Authors: Oh Chang-Kyun , Kim Yun-Jae , Baek Jong-Hyun , Kim Young-Pyo , Kim Woo-Sik
Published: July 2008

A local failure criterion for the API X65 steel is applied to predict ductile failure of full-scale API X65 pipes with simulated corrosion and gouge defects under internal pressure. The local failure criterion is the stress-modified fracture strain for the API X65 steel as a function of the stress triaxiality (defined by the ratio of the hydrostatic stress to the effective stress). Based on detailed FE analyses with the proposed local failure criteria, burst pressures of defective pipes are estimated and compared with experimental data. The Failure of corroded pipes is governed by local necking and plastic collapse in the defective region, rather than failure. For pipes with gouge defects, on the other hand, it is found that fracture is dominant. The predicted burst pressures are in good agreement with experimental data. Noting that an assessment equation against the gouge defect is not yet available, parametric study is performed, from which a simple equation is proposed to predict burst pressure for API X65 pipes with gouge defects.
High Pressure and Flow Rate Measurements on Peroxide Dosing Pumps Under Laboratory and Site Conditions
Authors: Trieb Franz H. , Karl Reinhard , Moderer Rene
Published: July 2008

The performance and reliability of peroxide dosing pumps are essential for every LDPE plant. The paper presents the results of measurement at an initiator injection pump under laboratory and site conditions. The recording was done with a flow meter and a high pressure transducer, both suitable for a maximum pressure of 400 MPa. It compares the results of hydraulic pressure inside the actuating cylinder at the intensifier with high pressure level and flow rate on the discharge connection of the pump. Direct measurement inside the high pressure cylinder and the possibilities to influence the fluctuations with a servo valve system round out the research work.
Engineering Approach to Creep Strain Modelling for a Multicast 9CR Steel
Authors: Holmstro¨m Stefan , Auerkari Pertti , Rantala Juhani
Published: July 2008

A simple, robust and effective parametric model has been developed to provide master curves of creep strain from uniaxial creep testing. The corresponding master curve has been produced for a multicast data set of P91 steel using data from both uninterrupted and interrupted creep tests. The time to specified creep strain at given stress and temperature was fitted in the strain range of 0.1 to 15%. With typical inhomogeneous creep data, the recommended approach involves a four-step procedure: initial investigation of the data quality, heat-specific intermediate modelling of the raw data, extraction of heat-specific stress-temperature-time values for selected evenly spaced range of strain, and re-fitting of these balanced values to the final master curve. The master curve is tested and validated for overall fitting efficiency comparison to other more complex models and to available 1% creep strain and failure predictions. Very competitive fitting efficiency was observed in spite of the simplicity of the model.
Sm
qnr
, a New Chromosome-Carried Quinolone Resistance Gene in
Stenotrophomonas maltophilia
Authors: Shimizu Kenichiro , Kikuchi Ken , Sasaki Takashi , Takahashi Namiko , Ohtsuka Masayuki , Ono Yuka , Hiramatsu Keiichi
Published: July 2008

A new chromosome-carried quinolone resistance gene from
Stenotrophomonas maltophilia
, Sm
qnr
, was characterized. The gene was present in type strain CCUG 5866 and was also detected in 24 clinical isolates and showed some allelic diversity. The expression of Sm
qnr
in
Escherichia coli
decreased the susceptibilities of the
E. coli
isolates to several fluoroquinolones.
Benefit of Having MultipleampDGenes for Acquiring β-Lactam Resistance without Losing Fitness and Virulence inPseudomonas aeruginosa
Authors: Moya Bartolomé , Juan Carlos , Albertí Sebastián , Pérez José L. , Oliver Antonio
Published: July 2008

The inactivation ofampDinPseudomonas aeruginosaleads to a partially derepressed phenotype, characterized by a moderately high level basalampCexpression that is still further inducible, due to the presence of two additionalampDgenes in this species (ampDh2andampDh3). The sequential inactivation of the threeampDgenes was shown to lead to a stepwise upregulation ofampCexpression, reaching full derepression in the triple mutant. To gain insight into the biological role ofP. aeruginosaAmpD multiplicity, we determined the effects of the inactivation of theampDgenes on fitness and virulence. We show that, in contrast to what was previously documented forSalmonellaspp., the inactivation ofampDinP. aeruginosadoes not affect fitness or virulence in a mouse model of systemic infection. This lack of effect was demonstrated to be dependent on the presence of the additionalampDgenes (ampDh2andampDh3), since the double and the tripleampDmutants completely lost their biological competitiveness and virulence; fullampCderepression and disruption of the AmpD peptidoglycan recycling system itself are both found to cause a major biological cost. Furthermore, among theampDgenes,ampDh3is found to be the most relevant for virulence inP. aeruginosa. Therefore, as a consequence of the presence of additionalampDgenes, partialampCderepression mediated byampDinactivation confers a biologically efficient resistance mechanism onP. aeruginosa.
Establishing In Vitro-In Vivo Correlations for
Aspergillus fumigatus
: the Challenge of Azoles versus Echinocandins
Authors: Arendrup Maiken Cavling , Perkhofer Susanne , Howard Susan J. , Garcia-Effron Guillermo , Vishukumar Aimanianda , Perlin David , Lass-Flörl Cornelia
Published: July 2008

Two clinical isolates of
Aspergillus fumigatus
, designated AT and DK, were recently obtained from patients failing caspofungin and itraconazole therapy, respectively. The isolates were tested by microdilution for susceptibility to itraconazole, voriconazole, posaconazole, ravuconazole, and caspofungin and by Etest for susceptibility to amphotericin B and caspofungin. Susceptibility testing documented that the DK isolate was azole resistant (itraconazole and posaconazole MICs, >4 μg/ml; voriconazole MIC, 2 μg/ml; ravuconazole MIC, 4 μg/ml), and the resistance was confirmed in a hematogenous mouse model, with mortality and the galactomannan index as the primary and secondary end points. Sequencing of the
cyp51A
gene revealed the M220K mutation, conferring multiazole resistance. The Etest, but not microdilution, suggested that the AT isolate was resistant to caspofungin (MIC, >32 μg/ml). In the animal model, this isolate showed reduced susceptibility to caspofungin. Sequencing of the
FKS1
gene revealed no mutations; the enzyme retained full sensitivity in vitro; and investigation of the polysaccharide composition showed that the β-(1,3)-glucan proportion was unchanged. However, gene expression profiling by Northern blotting and real-time PCR demonstrated that the
FKS
gene was expressed at a higher level in the AT isolate than in the susceptible control isolate. To our knowledge, this is the first report to document the presence of multiazole-resistant clinical isolates in Denmark and to demonstrate reduced susceptibility to caspofungin in a clinical
A. fumigatus
isolate with increased expression of the
FKS
gene. Further research to determine the prevalence of resistance in
A. fumigatus
worldwide, and to develop easier and reliable tools for the identification of such isolates in routine laboratories, is warranted.
Disposition, Metabolism, and Excretion of [
14
C]Doripenem after a Single 500-Milligram Intravenous Infusion in Healthy Men
Authors: Cirillo Iolanda , Mannens Geert , Janssen Cor , Vermeir Marc , Cuyckens Filip , Desai-Krieger Daksha , Vaccaro Nicole , Kao L. Mark , Devineni Damayanthi , Redman Rebecca , Turner Kenneth
Published: July 2008

In this open-label, single-center study, eight healthy men each received a single 500-mg dose of [
14
C]doripenem, containing 50 μCi of [
14
C]doripenem, administered as a 1-h intravenous infusion. The concentrations of unchanged doripenem and its primary metabolite (doripenem-M-1) resulting from β-lactam ring opening were measured in plasma and urine by a validated liquid chromatography method coupled to a tandem mass spectrometry assay. Total radioactivity was measured in blood, plasma, urine, and feces by liquid scintillation counting. Further metabolite profiling was conducted on urine samples using liquid chromatography coupled to radiochemical detection and high-resolution mass spectrometry. Unchanged doripenem and doripenem-M-1 accounted for means of 80.7% and 12.7% of the area under the plasma total-radioactivity-versus-time curve (area under the concentration-time curve extrapolated to infinity) and exhibited elimination half-lives of 1.1 and 2.5 h, respectively. Total clearance of doripenem was 16 liters/h, and renal clearance was 12.5 liters/h. At 7 days after the single dose, 95.3% of total doripenem-related radioactivity was recovered in urine and 0.72% in feces. A total mean of 97.2% of the administered dose was excreted in the urine as unchanged doripenem (78.7% ± 5.7%) and doripenem-M-1 (18.5% ± 2.6%). Most of the urinary recovery occurred within 4 h of dosing. Three additional minor metabolites were identified in urine: the glycine and taurine conjugates of doripenem-M-1 and oxidized doripenem-M-1. These results show that doripenem is predominantly eliminated in urine as unchanged drug, with only a fraction metabolized to doripenem-M-1 and other minor metabolites.
Bilateral facial nerve palsy associated with HIV seroconversion illness
Authors: Yeo J C L , Trotter M I , Wilson F
Published: July 2008

Bilateral facial nerve palsy is a rare but recognised manifestation of HIV seroconversion illness. The pathophysiology of this clinical presentation is thought to be associated with the immune response of the dissemination of virus throughout the body. We describe a case of bilateral facial nerve palsy, subsequently diagnosed with HIV. Related medical literature is also reviewed. The case highlights the vigilance required in unusual, atypical signs and symptoms if a diagnosis of HIV infection is not to be missed. Clinicians should be aware of the potential presentation of HIV seroconversion illness to provide opportunity for early diagnosis and intervention.
Multi-system complications of hypothermia: a case of recurrent episodic hypothermia with a review of the pathophysiology of hypothermia
Authors: Alty J E , Ford H L
Published: July 2008

A 61-year-old woman with secondary progressive multiple sclerosis presented on six occasions over a 2-year period with severe hypothermia (31–33.5°C). This resulted in numerous multi-system complications comprising acute pancreatitis, hepatitis, gastrointestinal haemorrhage, psychiatric disturbance, bradycardia, paradoxical sweating, thrombocytopenia, anaemia and raised inflammatory markers. Septic screens were consistently normal. On each occasion she was successfully treated with passive external rewarming and made a complete recovery. This is the first reported case of such extensive sequelae in a single patient with recurrent hypothermic episodes. This unusual patient provides an invaluable insight into the natural history and pathophysiology of hypothermia. The case report is followed by a review of dysfunctional thermoregulation and pathophysiology of hypothermia-induced multi-system complications. A key learning point is to recognise that the clinical manifestations of hypothermia may be widespread and serious but are nonetheless reversible. In addition, one should consider the differential diagnosis of covert hypothermia in those patients with episodic confusion, as hypothermia is under-recognised, particularly in older people, who are prone to accidental hypothermia, and in those with common neurological conditions, such as stroke, head injury and multiple sclerosis, that may have suboptimal thermoregulation.
A Review of the 1924 Kenogami Landslide
Authors: Brzezinski L. S.
Published: July 2008

A major landslide of the flow variety took place in the fall of 1924 in the Lake St. John region of the Province of Quebec, Canada. The slide involved 2.5 million cubic yards (2.0 × 106 m3) of clay and resulted in loss of life and considerable damage to property. A review of the circumstances preceding failure, the geotechnical properties of the clay and the mechanism of the slide movements is presented in the paper.
On Solutions of Plane Strain Consolidation Problems by Finite Element Methods
Authors: Hwang C. T. , Morgenstern N. R. , Murray D. W.
Published: July 2008

The formulation is presented of the equations governing the solution of true three-dimensional consolidation problems by means of finite element methods. The numerical procedure for handling the resulting algebraic equations is described briefly and detailed results from the solution of several problems are given. Excellent agreement is found between the numerical analysis and existing closed form solutions.
Observations of the Failure of a Vertical Cut in Clay at Welland, Ontario
Authors: Kwan D.
Published: July 2008

Results of an instrumented test excavation in Welland clay are presented with analysis, discussion, and conclusions. The field investigation includes an observation of a deep vertical slope failure as well as an inclined stable slope, and measurements of pore pressure and surface strain. The average in situ undrained strength indicates that the soil deposit excavated in the area is not soft.
Stabilization of Fine Sands Using Polyvinyl Acetate
Authors: Gamble Bruce R.
Published: July 2008

Consideration is given to the problems of constructing airfields of the fine surface materials typical of the arctic islands. Preliminary laboratory investigations into the use of a polyvinyl acetate binder as a means of increasing penetration resistance and providing stability against erosion in fine sands are reported. Load–penetration tests indicate that specimens treated by spraying or mixing with dilute polyvinyl acetate have greater penetration resistance and surface strength than comparable untreated specimens. Results depend upon the water content and completeness of curing at testing. Under favorable conditions 100% increases in penetration resistance can be obtained for a material cost of approximately $0.03/ft2 ($0.32/m2). Work with other polymer treatments less susceptible to water and curing conditions is proceeding.