bluuebunny/crossref_metadata_2025 huggingface dataset:
Low molecular weight heparin (LMWH) increases the efficacy of cisplatinum plus gemcitabine combination in advanced pancreatic cancer
Authors: Icli Fikri , Akbulut Hakan , Utkan Gungor , Yalcin Bülent , Dincol Dilek , Isikdogan Abdurrahman , Demirkazik Ahmet , Onur Handan , Cay Filiz , Büyükcelik Abdullah
Published: December 2006

Background

In this non‐randomized study we aimed to assess the efficacy of the addition of low molecular weight heparin (LMWH) to gemcitabine (GEM) plus cisplatinum (CDDP) combination chemotherapy on survival by prevention of thromboembolic complications in patients with advanced pancreatic cancer (APC).

Patients and Methods

Between November 1999 and February 2004, 69 consecutive patients with APC were treated with GEM (800 mg/m2, day 1, day 8) plus CDDP (35 mg/m2, day 1, day 8) every 21 days ±LMWH (nadroparine calcium, 2,850 IU/day until disease progression). Ten out of 35 patients in LMWH group and 10 out of 34 patients in chemotherapy alone group had primary inoperable locally advanced disease and the rest of the patients had metastatic disease.

Results

Total response rate was 58.8% (11.7% CR) for the patients treated with LMWH and 12.1% for those treated without LMWH (P = 0.0001). LMWH group had a better median time to progression (TTP) and survival when compared to control group (7.3 vs. 4.0 months,P = 0.0001; 13.0 vs. 5.5 months,P = 0.0001). The toxicity was similar and acceptable in both groups.

Conclusion

Addition of LMWH to GEM plus CDDP combination significantly improved the response and survival in patients with APC and the current schedule deserves to be tested in phase III trials. J. Surg. Oncol. 2007; 95: 507–512. © 2006 Wiley‐Liss, Inc.
Clear cell sarcoma of soft tissues
Authors: Malchau Sara Sofia , Hayden James , Hornicek Francis , Mankin Henry J.
Published: December 2006

Clear cell sarcoma (CCS) is a rare but highly malignant tumor of soft tissues often appearing as a small tender mass in the deep tissues of the distal extremities. We have studied 17 patients with such lesions treated since 1986 and have a high incidence of local recurrence and metastasis with a survival rate of only 47% despite surgery and for many of the patients, adjuvant therapy. The purpose of this article is to warn the readers of the dangers related to treating this seemingly benign lesion and urge them to perform wide surgery and utilize adjuvant therapy. J. Surg. Oncol. 2007; 95: 519–522. © 2006 Wiley‐Liss, Inc.
Prognostic impact of resection margin involvement after extended (D2/D3) gastrectomy for advanced gastric cancer: A 15‐year experience at a single institute
Authors: Cho Byoung Chul , Jeung Hei Cheul , Choi Hye Jin , Rha Sun Young , Hyung Woo Jin , Cheong Jae Ho , Noh Sung Hoon , Chung Hyun Cheol
Published: December 2006

Background and Objectives

The aim of this study was to investigate whether microscopic positive margins are detrimental to the outcome of gastric cancer patients treated with extended (D2/3) gastrectomy.

Methods

Among 2,740 consecutive patients who had undergone extended gastrectomy for advanced gastric cancer between January 1987 and December 2002, 49 patients (1.8%) had positive resection margins on final histology.

Results

Among 49 patients, 29 (59.2%) had proximal involved margins and 20 (40.8%) had distal involved margins. The median survival time of the positive margin group was 34 months. The negative margin group had a significantly longer median survival time of 69 months (P = 0.025). When both groups of patients were stratified according to nodal stage, a positive resection margin determined a worse prognosis only in patients with node‐negative disease (174 months vs. 37 months, P = 0.0001). In patients with nodal metastasis, the median survival time was similar in both groups.

Conclusions

Our results suggest that a positive microscopic margin is associated with a worse outcome in patients with node‐negative disease. Therefore, a more aggressive treatment, such as re‐operation, is needed in node‐negative patients with a positive microscopic disease. J. Surg. Oncol. 2007; 95: 461–468. © 2006 Wiley‐Liss, Inc.
Verbal and physical aggression in World War II former prisoners of war: Role of posttraumatic stress disorder and depression
Authors: O'Donnell Casey , Cook Joan M. , Thompson Richard , Riley Kevin , Neria Yuval
Published: December 2006

This study examined the relationship among posttraumatic stress disorder (PTSD), depression, and intimate partner relationship aggression in a community sample of World War II (WWII) male military former prisoners of war (POWs). Sixty percent of these POWs reported verbal aggression in their marriages, and 12% endorsed physical aggression. Both verbal and physical aggression were significantly correlated to the severity of captivity trauma and to PTSD symptoms. Posttraumatic stress disorder symptoms significantly mediated the relationship between severity of trauma and both verbal and physical aggression. Depression was a significant moderator of the relationship between PTSD and both physical and verbal aggression. Theoretical and clinical implications are suggested.
Changes in coping strategies, relationship to the perpetrator, and posttraumatic distress in female crime victims
Authors: Gutner Cassidy A. , Rizvi Shireen L. , Monson Candice M. , Resick Patricia A.
Published: December 2006

This study examined the relationship between changes in coping and posttraumatic stress disorder (PTSD) symptomatology among recent female rape and physical assault victims as a function of assault type and perpetrator status. Participants were assessed within 1 month after trauma and again at 3 months after trauma. Results indicate that changes in coping strategies over time are associated with the severity of the PTSD symptoms. Assault type was not a significant factor in the association between changes in coping and PTSD, but perpetrator status was. Victims with known perpetrators, who coped more by social withdrawal, had more severe PTSD symptoms over time. The importance of examining the dynamic nature of coping in the development of PTSD is discussed.
Cumulative interpersonal traumas and social support as risk and resiliency factors in predicting PTSD and depression among inner‐city women
Authors: Schumm Jeremiah A. , Briggs‐Phillips Melissa , Hobfoll Stevan E.
Published: December 2006

This study represents one of the largest examinations of how child abuse, adult rape, and social support impact inner‐city women (N = 777). Using retrospective self‐report, the effects of interpersonal trauma were shown to be cumulative such that women who experienced either child abuse or adult rape were 6 times more likely to have probable posttraumatic stress disorder (PTSD), whereas women who experienced both child abuse and rape were 17 times more likely to have probable PTSD. High social support predicted lower PTSD severity for women who experienced both child abuse and adult rape, but not for women who reported one or none of these traumas. Results suggest that social support, when left intact, might buffer the cumulative impact of child and adult interpersonal traumas.
Is mixed‐handedness a marker of treatment response in posttraumatic stress disorder?: A pilot study
Authors: Forbes David , Carty Jessica , Elliott Peter , Creamer Mark , McHugh Tony , Hopwood Malcolm , Chemtob Claude M.
Published: December 2006

Recent studies suggest that mixed‐handedness is a risk factor for posttraumatic stress disorder (PTSD). This study examined whether mixed‐handed veterans with combat‐related PTSD respond more poorly to psychosocial treatment. Consistency of hand preference was assessed in 150 Vietnam combat veterans with PTSD using the Edinburgh Handedness Inventory (R. C. Oldfield, 1971). Growth modeling analyses using Mplus (L. K. Muthén & B. Muthén, 2002) identified that PTSD veterans with mixed‐handedness reported significantly less treatment improvement on the PTSD Checklist (F. W. Weathers, B. T. Litz, D. S. Herman, J. A. Huska, & T. M. Keane, 1993) than did veterans with consistent handedness. These data suggest that mixed‐handedness is associated with poorer PTSD treatment response. Several possible explanations for this finding are discussed.
University of Rhode Island Change Assessment–Trauma: Preliminary psychometric properties in an alcohol‐dependent PTSD sample
Authors: Hunt Yvonne M. , Kyle Tiffany L. , Coffey Scott F. , Stasiewicz Paul R. , Schumacher Julie A.
Published: December 2006

The co‐occurrence of posttraumatic stress disorder with substance use disorders (PTSD‐SUD) is common and is associated with poorer treatment outcomes. Attrition represents an ongoing, but poorly understood challenge in PTSD‐SUD treatment research. The current study examined the initial psychometric properties of the University of Rhode Island Change Assessment—Trauma (URICA‐T), a scale designed to assess attitudes and behaviors related to addressing trauma issues, in a sample of 42 individuals meeting diagnostic criteria for PTSD and alcohol dependence. Results suggest that the URICA‐T may have acceptable psychometric properties as a continuous measure of motivational readiness in a PTSD‐SUD sample. Preliminary data also suggests higher URICA‐T scores are associated with retention of alcohol dependent‐PTSD participants in a study utilizing trauma‐focused exposure.
Posttraumatic stress disorder and treatment seeking in a nationally representative Canadian military sample
Authors: Fikretoglu Deniz , Brunet Alain , Schmitz Norbert , Guay Stephane , Pedlar David
Published: December 2006

This study aimed to identify predictors of treatment seeking in military members with posttraumatic stress disorder (PTSD) using data from the 2002 Canadian Community Health Survey–Canadian Forces Supplement (Statistics Canada, 2003). To identify predictors, two complementary analyses (binary logistic regression and recursive partitioning of independent variables) were conducted in military members with PTSD (N = 509). Results indicate that trauma‐related (index traumatic event type, cumulative trauma exposure), demographic (marital status), enabling (income), and need (PTSD interference) factors predict treatment seeking in military members with PTSD, and that treatment seekers and nontreatment seekers are both comprised of distinct subgroups. Interventions aimed at increasing treatment‐seeking behaviors should be tailored to the specific needs of various subgroups of nontreatment seekers.
The impact of resource loss and traumatic growth on probable PTSD and depression following terrorist attacks
Authors: Hobfoll Stevan E. , Tracy Melissa , Galea Sandro
Published: December 2006

The authors interviewed by phone 2,752 randomly selected individuals in New York City within 6 to 9 months after the attacks of September 11, 2001 on the World Trade Center, and 1,939 of these were reinterviewed at a 12‐ to 16‐month follow‐up. It was hypothesized that resource loss would significantly predict probable posttraumatic stress disorder (PTSD) and probable depression since September 11, and that resource loss's impact would be independent of previously identified predictors relating to individuals' demographic characteristics, history of stressful event exposure, prior trauma history, peritraumatic experience, and social support. Second, it was predicted that reported traumatic growth would be related to greater, not lesser, psychological distress. The authors' findings supported their hypotheses for resource loss, but traumatic growth was unrelated to psychological outcomes when other predictors were controlled.
The association between childhood abuse, PTSD, and the occurrence of adult health problems: Moderation via current life stress
Authors: Cromer Kiara R. , Sachs‐Ericsson Natalie
Published: December 2006

The association between childhood abuse, current life stressors, and the occurrence of adult medical problems was investigated in the National Comorbidity Survey. It was found that after controlling for a number of covariates, current life stressors moderated the relationship between abuse history and medical problems such that health problems were greater for individuals who had been abused in the presence of current stressors. The findings suggest that a history of childhood abuse, even without the presence of posttraumatic stress disorder (PTSD), can influence the occurrence of poor health if current life stressors are present. Future directions and implications are discussed.
Positive and negative adjustment and social support of sexual assault survivors
Authors: Borja Susan E. , Callahan Jennifer L. , Long Patricia J.
Published: December 2006

The roles of positive (i.e., growth) and negative (i.e., posttraumatic stress symptoms and general symptomatology) adjustment following adult sexual assault experience(s) were examined using a standardized definition of abuse. These reactions were explored in association with positive and negative support from formal and informal providers. Finally, using standardized measures, the collective impact of positive and negative support, formal and informal support were investigated in predicting positive and negative psychological adjustment. Both forms of informal support were found to be associated with positive outcomes. Only negative informal support was associated with posttraumatic stress symptoms. First responders should consider whether support resources are appropriate to victims' needs.
Correlates of posttraumatic growth in survivors of intimate partner violence
Authors: Cobb Amanda R. , Tedeschi Richard G. , Calhoun Lawrence G. , Cann Arnie
Published: December 2006

The negative consequences of intimate partner violence are well documented. This study investigated the possibility that some survivors of intimate partner violence may also experience posttraumatic growth because of their struggle with this highly stressful circumstance. In addition, the relationships between posttraumatic growth and relationship status, type of abuse, depression, and availability of models of posttraumatic growth were examined. Most women reported posttraumatic growth. Overall abuse experienced and depression were unrelated to posttraumatic growth, but abuse was related to one domain of growth. Contact with a model of posttraumatic growth and having left an abusive relationship were both positively related to posttraumatic growth.
El Salvador earthquakes: Relationships among acute stress disorder symptoms, depression, traumatic event exposure, and resource loss
Authors: Sattler David N. , de Alvarado Ana Maria Glower , de Castro Norma Blandon , Male Robert Van , Zetino A. M. , Vega Raphael
Published: December 2006

Four and seven weeks after powerful earthquakes in El Salvador, the authors examined the relationships among demographics, traumatic event exposure, social support, resource loss, acute stress disorder (ASD) symptoms, depression, and posttraumatic growth. Participants were 253 college students (Study 1) and 83 people in the community (Study 2). In Study 1, female gender, traumatic event exposure, low social support, and loss of personal characteristic, condition, and energy resources contributed to ASD symptoms and depression. In Study 2, damage to home and loss of personal characteristic and object resources contributed to ASD symptoms and depression. Posttraumatic growth was not associated with ASD symptoms or depression. Findings support the conservation of resources stress theory (Hobfoll, 1998). Resource loss spirals, excessive demands on coping, and exposure to multiple disasters are discussed.
Traumatic events and alcohol use disorders among American Indian adolescents and young adults
Authors: Boyd‐Ball Alison J. , Manson Spero M. , Noonan Carolyn , Beals Janette
Published: December 2006

This study examined the relationship between severe traumatic events and alcohol use disorders in American Indian adolescents and young adults. Interviews of 432 adolescents and young adults who were enrolled tribal members living on or near two closely related American Indian reservations were used. Results indicated that severe trauma increased the odds of alcohol use disorders (p <.001), with the number of traumas having a dose‐dependent effect. The authors conclude that trauma is associated with alcohol use disorders in this population. This study's findings yield important insights into the risks in American Indian adolescents and young adults that may result from early trauma, as well as implications for the timing and possible settings for intervention.
Childhood abuse and intake severity in alcohol disorder patients
Authors: Zlotnick Caron , Johnson Dawn M. , Stout Robert L. , Zywiak William H. , Johnson Jennifer E. , Schneider Robert J.
Published: December 2006

In a sample of 336 patients with an alcohol use disorder, this study examined, whether patients with histories of childhood sexual abuse (CSA) and childhood physical abuse (CPA) compared to those without such histories have a greater severity of alcohol and other clinical difficulties. Whether lifetime posttraumatic stress disorder (PTSD) mediates the relationship between childhood abuse and clinical outcomes was explored. Results were that CSA was associated with earlier age of onset for alcohol disorder, greater Axis I comorbidity as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM‐IV; American Psychiatric Association, 1994), more social and psychiatric problems, but lower drinking frequency. Childhood physical abuse was related to greater drinking consequences, social and psychiatric dysfunction, and Axis I comorbidity, but also lower drinking frequency. Posttraumatic stress disorder partially mediated the effect of both CSA and CPA on severity of psychiatric problems.
Posttraumatic stress after a motor vehicle accident: A six‐month follow‐up study utilizing latent growth modeling
Authors: Wu Kitty K. , Cheung Mike W. L.
Published: December 2006

Features of posttraumatic stress disorder (PTSD) for 596 survivors of motor vehicle accidents were examined by self‐report measures at 1 week, 1 month, 3 months, and 6 months after the motor vehicle accident (MVA). Latent growth modeling was utilized to study the trend and predictors of the level of distress. Results indicated that 5–20% of the participants reported to have a significant level of posttraumatic stress in one, two, or three of the PTSD symptom clusters within the period studied. Survivors with significant acute stress 1 week after the MVA had a higher risk for developing chronic posttraumatic stress. Although the severity of intrusive and hyperarousal symptoms decreased over time, the severity of avoidance symptoms remained unchanged. Factors predicting the course of PTSD after an MVA are identified.
Coping, symptoms, and functioning outcomes of patients with posttraumatic stress disorder
Authors: Tiet Quyen Q. , Rosen Craig , Cavella Steven , Moos Rudolf H. , Finney John W. , Yesavage Jerome
Published: December 2006

This study examines the association between approach coping and better functioning outcomes and the reciprocal relationships between coping and posttraumatic stress disorder (PTSD) symptoms in patients diagnosed with PTSD. Posttraumatic stress disorder patients receiving services in five VA health care systems were randomly selected and surveyed at baseline and followed 10 months later. Analyses of longitudinal data using structural equation modeling techniques showed that more approach coping predicted better family and social functioning. Cognitive avoidance coping predicted more PTSD symptoms, and more PTSD symptoms predicted more approach coping and more behavioral avoidance coping. Approach coping may enable patients with chronic PTSD to establish and maintain better relationships with family and friends, despite continuing PTSD.
Maximizing follow‐up in longitudinal studies of traumatized populations
Authors: Scott Christy K. , Sonis Jeffrey , Creamer Mark , Dennis Michael L.
Published: December 2006

Although longitudinal research is essential in understanding the nature and course of posttraumatic mental health problems, high rates of attrition often threaten the internal validity of such studies and make results hard to interpret. C. K. Scott (2004) developed an approach to minimizing attrition in longitudinal studies that consistently yielded retention rates in excess of 90% through to 2‐year follow‐up. In this article, the authors discuss the interface between trauma exposure and participation in longitudinal research, before describing in detail a model to address those effects. The effectiveness of the model is examined with reference to traumatic stress in a large community sample (N= 887) with eight waves of data over 2 years.
Catalytic Olefin Polymerization is a Mature Field. Isn't it?
Authors: Busico Vincenzo
Published: December 2006

In spite of the reputation to be a mature area, Ziegler‐Natta olefin polymerization continues to produce scientific and industrial breakthroughs at a surprising pace. The massive introduction of High Throughput Screening technologies has accelerated the innovation process even further. This Highlight aims at introducing the reader to a number of very recent publications in which novel metallocene and non‐metallocene (“post‐metallocene”) olefin polymerization catalysts, and new concepts of chain growth in insertion polymerization, are disclosed and elegantly and convincingly discussed.

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Stimuli‐Responsive Multilayered Hybrid Nanoparticle/Polyelectrolyte Capsules
Authors: De Geest Bruno G. , Skirtach Andrei G. , De Beer Thomas R. M. , Sukhorukov Gleb B. , Bracke Lieven , Baeyens Willy R. G. , Demeester Joseph , De Smedt Stefaan C.
Published: December 2006

Gold nanoparticles (AuNP) with carboxyl groups on their surface were used in combination with PAH for the layer‐by‐layer coating of CaCO3 microparticles, followed by the dissolution of the CaCO3 core. SEM, TEM, and confocal microscopy are used to characterize the hybrid nanoparticles/polyelectrolyte capsules. As the AuNP have carboxyl groups on their surface, their charge density is pH dependent; therefore, the capsules exhibit a pH‐dependent swelling and can be deconstructed both at low and high pH. By covalent cross‐linking of the carboxyl groups of the AuNP and the amino groups of the PAH, it is possible to suppress the pH‐responsive behavior. AuNP are used as activation centers using IR light and this ability is used to release encapsulated material from the nanoparticles/polyelectrolyte capsules as well as for the enhancement of detection and imaging of such capsules by Raman microspectrosopy.

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Efficient organization of information processing
Authors: Cukrowski Jacek , Fischer Manfred M.
Published: December 2006

The paper examines the application of the concept of economic efficiency to organizational issues of collective information processing in decision making. Information processing is modeled in the framework of the dynamic parallel processing model of associative computation with an endogenous setup cost of the processors. The model is extended to include the specific features of collective information processing in the team of decision makers which may lead to an error in data analysis. In such a model, the conditions for efficient organization of information processing are defined and the architecture of the efficient structures is considered. We show that specific features of collective decision making procedures require a broader framework for judging organizational efficiency than has traditionally been adopted. In particular, and contrary to the results available in economic literature, we show that there is no unique architecture for efficient information processing structures, but a number of various efficient forms. The results indicate that technological progress resulting in faster data processing (ceteris paribus) will lead to more regular information processing structures. However, if the relative cost of the delay in data analysis increases significantly, less regular structures could be efficient. Copyright © 2007 John Wiley & Sons, Ltd.
Hidden monopsony rents in winner‐take‐all markets—sport and economic contribution of Spanish soccer players
Authors: Garcia‐del‐Barrio Pedro , Pujol Francesc
Published: December 2006

In labor markets where few companies compete for many workers, economic theory predicts monopsony rents. Surprisingly, soccer clubs do not profit from the expected rents. The purpose of this study is to explain such contradictory evidence.

Our model and empirical test, using data obtained from the Spanish professional soccer league for the season 2001/2002, suggests that monopsony rents that the clubs were to obtain from most of the soccer players would eventually revert to the superstars. The study also illustrates that the market value of players stems both from their sporting performance and their economic contribution. Copyright © 2007 John Wiley & Sons, Ltd.
Correction of errors in Vetschera's (2004) model of behavioral uncertainty and investment
Authors: Tularam G.A. , Soomro A.S.
Published: December 2006

Modelling of behavioural uncertainty has been a concern for researchers for some time. This paper briefly reviews modelling related to uncertainty and the focuses on the model presented by Vetschera (2004). A model of decision behaviour has been developed in the paper with regard to investment and cooperation taking into account the uncertainty and lack of information. The model is an important contribution for it focuses on situations that are not usual to the normal principle agent problems. The present review however reveals some errors in the paper. Sometimes errors may appear editorial but the same errors may lead the interested reader or researcher to inappropriate paths, particularly those who may fail to follow an argument or comprehend the underlying meanings of the equations and analytical solutions. In this manner, further work on this important topic may be hindered if researchers accept forms as presented in the paper literally as facts to further work. The main contribution of this paper is that it presents the correct forms of the mathematical aspects and procedures of the Vetschera (2004) paper. Copyright © 2007 John Wiley & Sons, Ltd.
Context is everything: Mining the normal and preneoplastic microenvironment for insights into the diet and cancer risk conundrum
Authors: Hord Norman G. , Fenton Jenifer I.
Published: December 2006

This review highlights the context‐dependence of epithelial carcinogenesis in order to illuminate the potential for progress in the field of diet and cancer prevention. Estimates drawn from observational epidemiology imply that diet and lifestyle changes have the potential to prevent 30–40% of cancer cases. However, the application of knowledge gleaned from observational epidemiology applied to randomized clinical trials (RCT) has yielded equivocal or negative results. Resolving this conundrum requires: (i) advances in diet assessment methodologies and the design of clinical trials; (ii) greater knowledge of the active components within foods which may impact cancer risk; and (iii) knowledge about the effects of dietary components on susceptible tissues throughout the disease process (Meyskens, F. L., Jr., Szabo, E., Diet and cancer: The disconnect between epidemiology and RCT. Cancer Epidemiol. Biomarkers Prev. 2005, 14, 1366–1369). Explicit consideration of the causal criteria will pay tangible benefits in the design of basic, clinical, and epidemiologic studies in cancer prevention. The rational identification of diet‐dependent physiologic targets for cancer prevention is best pursued by appreciating context‐dependence of epithelial carcinogenesis. Five contexts, or paradigms useful in understanding the multifactorial nature of carcinogenesis, are offered which describe the potential diet‐associated physiologic influences on normal and preneoplastic cells and tumor microenvironments. Taken together with the interactions of systemic, endocrine, and autocrine/paracrine signals that may modulate the process of carcinogenesis, we can appreciate how dietary factors may act collectively in normal tissues or at early stages of carcinogenesis to prevent cancer. Only by understanding the effect of dietary components on the cellular and stromal components of the tissue microenvironment early in the process of epithelial carcinogenesis will yield clues useful for the development of improved strategies for cancer prevention.
Toxins of cyanobacteria
Authors: van Apeldoorn Marian E. , van Egmond Hans P. , Speijers Gerrit J. A. , Bakker Guido J. I.
Published: December 2006

Blue‐green algae are found in lakes, ponds, rivers and brackish waters throughout the world. In case of excessive growth such as bloom formation, these bacteria can produce inherent toxins in quantities causing toxicity in mammals, including humans. These cyanotoxins include cyclic peptides and alkaloids. Among the cyclic peptides are the microcystins and the nodularins. The alkaloids include anatoxin‐a, anatoxin‐a(S), cylindrospermopsin, saxitoxins (STXs), aplysiatoxins and lyngbyatoxin. Both biological and chemical methods are used to determine cyanotoxins. Bioassays and biochemical assays are nonspecific, so they can only be used as screening methods. HPLC has some good prospects. For the subsequent detection of these toxins different detectors may be used, ranging from simple UV‐spectrometry via fluorescence detection to various types of MS. The main problem in the determination of cyanobacterial toxins is the lack of reference materials of all relevant toxins. In general, toxicity data on cyanotoxins are rather scarce. A majority of toxicity data are known to be of microcystin‐LR. For nodularins, data from a few animal studies are available. For the alkaloids, limited toxicity data exist for anatoxin‐a, cylindrospermopsin and STX. Risk assessment for acute exposure could be relevant for some types of exposure. Nevertheless, no acute reference doses have formally been derived thus far. For STX(s), many countries have established tolerance levels in bivalves, but these limits were set in view of STX(s) as biotoxins, accumulating in marine shellfish. Official regulations for other cyanotoxins have not been established, although some (provisional) guideline values have been derived for microcystins in drinking water by WHO and several countries.
Fully Crosslinked Poly[cyclotriphosphazene‐co‐(4,4′‐sulfonyldiphenol)] Microspheres via Precipitation Polymerization and Their Superior Thermal Properties
Authors: Zhu Lu , Zhu Yan , Pan Yang , Huang Yawen , Huang Xiaobin , Tang Xiaozhen
Published: December 2006

Fully crosslinked, stable poly[cyclotriphosphazene‐co‐(4,4′‐sulfonyldiphenol)] (PZS) microspheres have been prepared via the polycondensation between hexachlorocyclotriphosphazene and 4,4′‐sulfonyldiphenol by precipitation polymerization. The diameter of the PZS microspheres ranged from 0.6 to 1.0 µm with the specific surface area of the microspheres ranging from 11.7 to 10.1 m2 · g−1. The formation of the non‐porous microspheres was observed to obey an oligomeric species absorbing mechanism. The fully crosslinked chemical structure of the PZS microspheres were determined by IR, CP/MAS NMR, XRD, and EDX. No glass‐transition temperature was observed and the onset of the thermal‐degradation temperature was 542 °C. Thermal stability of the PZS microspheres by the precipitation polycondensation was significantly improved as compared with crosslinked microspheres produced by addition polymerizations.

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Thermomechanical homogenization analysis of axisymmetric inelastic solids at finite strains based on an incremental minimization principle
Authors: Celigoj C. C.
Published: December 2006

The paper presents an attempt to extend homogenization analysis to axisymmetric solids under thermo‐ mechanical loading. In axisymmetric solids, under axisymmetric thermomechanical loading and/or torsion, on both scales, macro and micro, the displacement and rotation response is by definition independent of the cylindrical angle co‐ordinate.

In homogenization analysis the deformation of the micro‐structure is driven by the deformation gradient F̄ of the macro‐structure and enhanced by a micro‐scale fluctuation field ũ, such that: x=F̄·X+ũ and in consequence F=F̄+F̃.

What is new: on the micro‐scale, the fact of independence of the cylindrical angle co‐ordinate imposes the homogeneous or Taylor‐assumption on the fluctuation field ũ of the R(epresentative) V(olume) E(lement) in the radial direction, whereas the other two fluctuation fields, the torsional angle and the axial displacement , are not affected. The thermomechanical problem on the macroscale is solved via a split approach: an isentropic mechanical phase, an isogeometrical thermal phase, and—in case of inelasticity—an update phase of the internal micro‐variables.

The homogenization of inelastic solid materials at finite strains is based on an incremental minimization principle, recently introduced by Miehe et al. (J. Mech. Phys. Solids 2002; 50:2123–2167).

Two finite element examples demonstrate the viability of the proposed approach. Copyright © 2006 John Wiley & Sons, Ltd.
Locality constraints within multiscale model for non‐linear material behaviour
Authors: Hund Andrea , Ramm Ekkehard
Published: December 2006

This paper presents a two‐scale approach for the mechanical and numerical modelling of materials with microstructure‐like concrete or fibre‐reinforced concrete in the non‐linear regime. It addresses applications, where the assumption of scale separation as the basis for classical homogenization methods does not hold. This occurs when the resolution of micro and macro scale does not differ ab initio or when evolving fluctuations in the macro‐fields are in the order of the micro scale during the loading progress. Typical examples are localization phenomena. The objective of the present study is to develop an efficient solution method exploiting the physically existing multiscale character of the problem. The proposed method belongs to the superposition‐based methods with local enrichment of the large‐scale solution ū by a small‐scale part u′. The main focus of the present formulation is to allow for locality of the small‐scale solution within the large‐scale elements to achieve an efficient solution strategy. At the same time the small‐scale information exchange over the large‐scale element boundaries is facilitated while maintaining the accuracy of a refined complete solution. Thus, the emphasis lies on finding appropriate locality constraints for u′. To illustrate the method the formulation is applied to a damage mechanics based material model for concrete‐like materials. Copyright © 2006 John Wiley & Sons, Ltd.
The role of geometric stiffness in momentum and energy conserving time integration
Authors: Krenk Steen
Published: December 2006

A momentum and energy conserving time integration algorithm is developed for the motion of elastic bodies described in terms of the quadratic Green strain. Momentum conserving algorithms are formulated from an integral of the equations of motion and energy conservation has traditionally been obtained by evaluating the contribution from the internal forces by use of a combined mean value of stresses and virtual strains on the element level. It is here demonstrated that momentum and energy conservation can be obtained from the classic central difference formulation by including an extra global term in the form of the increment of the geometric stiffness matrix over the current time step, usually directly available in global form in existing finite element programmes. The theory is derived by the use of a state‐space formulation, where this extra term is located in the same position as the viscous damping matrix, indicating that the effect of the extra incremental geometric stiffness term in the non‐linear algorithm is equivalent to a variable damping term depending on the change of the state of stress over a time increment. In the actual numerical algorithm, the new value of the velocity vector is eliminated, leaving a non‐linear equation for the displacement increment alone, followed by an explicit vector update of the velocity increment. Copyright © 2006 John Wiley & Sons, Ltd.
Improved global convergence probability using multiple independent optimizations
Authors: Schutte J. F. , Haftka R. T. , Fregly B. J.
Published: December 2006

For some problems global optimization algorithms may have a significant probability of not converging to the global optimum or require an extremely large number of function evaluations to reach it. For such problems, the probability of finding the global optimum may be improved by performing multiple independent short searches rather than using the entire available budget of function evaluations on a single long search. The main difficulty in adopting such a strategy is to decide how many searches to carry out for a given function evaluation budget. The basic premise of this paper is that different searches may have substantially different outcomes, but they all start with rapid initial improvement of the objective function followed by much slower progress later on. Furthermore, we assume that the number of function evaluations to the end of the initial stage of rapid progress does not change drastically from one search to another for a given problem and algorithmic setting. Therefore we propose that the number of function evaluations required for this rapid‐progress stage be estimated with one or two runs, and then the same number of function evaluations be allocated to all subsequent searches. We show that these assumptions work well for the particle swarm optimization algorithm applied to a set of difficult analytical test problems with known global solutions. For these problems we show that the proposed strategy can substantially improve the probability of obtaining the global optimum for a given budget of function evaluations. We also test a Bayesian criterion for estimating the probability of having reached the global optimum at the end of the series of searches and find that it can provide a conservative estimate for most problems. Finally, we demonstrate the approach on a particularly challenging engineering design problem constructed so as to have at least 32 widely separated local optima. Copyright © 2006 John Wiley & Sons, Ltd.
Theoretical aspects of the smoothed finite element method (SFEM)
Authors: Liu G. R. , Nguyen T. T. , Dai K. Y. , Lam K. Y.
Published: December 2006

This paper examines the theoretical bases for the smoothed finite element method (SFEM), which was formulated by incorporating cell‐wise strain smoothing operation into standard compatible finite element method (FEM). The weak form of SFEM can be derived from the Hu–Washizu three‐field variational principle. For elastic problems, it is proved that 1D linear element and 2D linear triangle element in SFEM are identical to their counterparts in FEM, while 2D bilinear quadrilateral elements in SFEM are different from that of FEM: when the number of smoothing cells (SCs) of the elements equals 1, the SFEM solution is proved to be ‘variationally consistent’ and has the same properties with those of FEM using reduced integration; when SC approaches infinity, the SFEM solution will approach the solution of the standard displacement compatible FEM model; when SC is a finite number larger than 1, the SFEM solutions are not ‘variationally consistent’ but ‘energy consistent’, and will change monotonously from the solution of SFEM (SC = 1) to that of SFEM (SC → ∞). It is suggested that there exists an optimal number of SC such that the SFEM solution is closest to the exact solution. The properties of SFEM are confirmed by numerical examples. Copyright © 2006 John Wiley & Sons, Ltd.
A non‐stationary covariance‐based Kriging method for metamodelling in engineering design
Authors: Xiong Ying , Chen Wei , Apley Daniel , Ding Xuru
Published: December 2006

Metamodels are widely used to facilitate the analysis and optimization of engineering systems that involve computationally expensive simulations. Kriging is a metamodelling technique that is well known for its ability to build surrogate models of responses with non‐linear behaviour. However, the assumption of a stationary covariance structure underlying Kriging does not hold in situations where the level of smoothness of a response varies significantly. Although non‐stationary Gaussian process models have been studied for years in statistics and geostatistics communities, this has largely been for physical experimental data in relatively low dimensions. In this paper, the non‐stationary covariance structure is incorporated into Kriging modelling for computer simulations. To represent the non‐stationary covariance structure, we adopt a non‐linear mapping approach based on parameterized density functions. To avoid over‐parameterizing for the high dimension problems typical of engineering design, we propose a modified version of the non‐linear map approach, with a sparser, yet flexible, parameterization. The effectiveness of the proposed method is demonstrated through both mathematical and engineering examples. The robustness of the method is verified by testing multiple functions under various sampling settings. We also demonstrate that our method is effective in quantifying prediction uncertainty associated with the use of metamodels. Copyright © 2006 John Wiley & Sons, Ltd.
Detection of fetomaternal hemorrhage following chorionic villus sampling by Kleihauer Betke test and rise in maternal serum alpha feto protein
Authors: Katiyar Richa , Kriplani Alka , Agarwal Nutan , Bhatla Neerja , Kabra Madhulika
Published: December 2006

Objectives

To assess incidence and volume of fetomaternal hemorrhage (FMH) after chorionic villus sampling (CVS) by Kleihauer Betke test (KBT) and rise in maternal protein (MSAFP).

Methods

A prospective study was conducted on 61 cases requiring CVS. FMH due to CVS was assessed by KBT and MSAFP.

Results

Out of 61 cases, 60 (98.36%) cases showed FMH by MSAFP while all showed FMH by KBT. Median volume of FMH detected by MSAFP was 0.06 mL (25 to 75th interquartile (IQR) 0.01 to 0.12 mL) and by KBT was 0.45 mL (25 to 75th IQR 0.09 to 0.90). Mean volume of FMH detected by MSAFP was 0.1 + 0.1424 mL and by KBT was 0.58 + 0.637 mL. Significant FMH up to 0.1 mL was found in 20 (32.8%) and 45 (60.6%) by MSAFP and KBT respectively.

Conclusion

MSAFP and KBT are sensitive to detect FMH. KBT estimates more FMH than MSAFP. Fifty micrograms of anti‐D is sufficient to cover FMH during CVS. Copyright © 2006 John Wiley & Sons, Ltd.
Hepatitis B vaccine and risk of autoimmune thyroid disease: a Vaccine Safety Datalink study
Authors: Yu Onchee , Bohlke Kari , Hanson Christi A. , Delaney Kristin , Rees Thomas G. , Zavitkovsky Ann , Ray Paula , Mullooly John , Black Steven B. , Benson Patti , Thompson William W. , Davis Robert L. , Jackson Lisa A.
Published: December 2006

Purpose

Hepatitis B vaccine has been postulated as a possible cause of autoimmune disorders, including autoimmune thyroid diseases (ATD). Cases of Graves' disease and Hashimoto's thyroiditis, following hepatitis B vaccine have been reported to the Vaccine Adverse Events Reporting System (VAERS). To test the hypothesis that hepatitis B vaccine increases the risk of ATD, we conducted a case‐control study, within the Vaccine Safety Datalink project.

Methods

We identified potential cases of Graves' disease and Hashimoto's thyroiditis, among persons aged 18–69 years from administrative data recorded by three health maintenance organizations (HMOs) and verified cases by medical record review. Controls were frequency‐matched to cases by birth year, sex, and study site. Vaccine information was collected from administrative records, chart review, and telephone interviews with study subjects. We enrolled 355 Graves' disease cases, 418 Hashimoto's thyroiditis cases, and 1102 controls. We assessed the association between ever‐receipt of hepatitis B vaccine, as well as receipt of hepatitis B vaccine less than 1 year, 1–5 years and at least 5 years prior to the index date, and the risk of ATD.

Results

Ever‐receipt of hepatitis B vaccine was not associated with risk of Graves' disease (odds ratio (OR), 0.90; 95% confidence interval (CI), 0.62–1.32) or Hashimoto's thyroiditis (OR, 1.23; 95%CI, 0.87–1.73). There was also no association between the time interval since receipt of hepatitis B vaccination and either outcome.

Conclusions

We did not observe an increased risk of Graves' disease or Hashimoto's thyroiditis, following receipt of hepatitis B vaccine. Copyright © 2007 John Wiley & Sons, Ltd.
PTC effect and structure of polymer composites based on polyethylene/polyoxymethylene blend filled with dispersed iron
Authors: Mamunya Y.P. , Muzychenko Y.V. , Lebedev E.V. , Boiteux G. , Seytre G. , Boullanger C. , Pissis P.
Published: December 2006

The temperature dependence of resistivity, structure, and thermal expansion of composites based on polyethylene/polyoxymethylene (PE/POM) blends filled with dispersed iron (Fe) have been studied. The dependence of conductivity on filler content shows percolation behavior, with the values of the percolation thresholds equal to 21 vol% for PE‐Fe, 24 vol% for POM‐Fe, and 9 vol% for the filled blend PE/POM‐Fe, with two‐step character of the conductivity curve. The evolution of structure of the composite PE/POM‐Fe demonstrates transition from polymer matrix POM‐Fe, with inclusions of PE through cocontinuous phases of both POM‐Fe and PE, to PE matrix, with inclusions of POM‐Fe. Such a structure occurs due to localization of the filler only in one of the polymer phases, namely in POM. Measurements of the coefficient of thermal expansion α show the presence of two values of α: higher value (equal to α of PE) and lower value (equal to α of POM‐Fe), the transition between them corresponding to the structure with cocontinuous phases. The PE/POM‐Fe composites demonstrate double‐positive temperature coefficient (PTC) effect, with the presence of two transitions and a plateau between them. In such a system, two contributions to the PTC effect coexist: the first contribution originates from the thermal expansion of the nonconductive PE phase with higher value of the coefficient α, which leads to the break of the continuity of the conductive POM‐Fe phase; the second contribution originates from the break of the conductive structure of the filler inside the POM‐Fe phase because of the morphological changes in the vicinity of the melting temperature of POM. The double PTC effect is explained in terms of these two processes (thermal expansion and melting). POLYM. ENG. SCI., 47:34–42, 2007. © 2006 Society of Plastics Engineers
Preparation and properties of electrospun poly(vinyl alcohol)/silver fiber web as wound dressings
Authors: Hong Kyung Hwa
Published: December 2006

A novel wound dressing material was prepared by electrospinning poly(vinyl alcohol) (PVA)/AgNO3 aqueous solution into nonwoven webs and then treating the webs by heat or UV radiation. Through SEM, TEM, and XPS analyses, it was observed that the silver (Ag) nanoparticles were generated and existed in the near surface of the electrospun nanofibers. It was found that heat treatment as well as UV radiation reduced the Ag+++ ions in the electrospun PVA/AgNO3 fiber web into the Ag nanoparticles. Also the heat treatment improved the crystallinity of the electrospun PVA fiber web and so it made the web unsolved in moisture environment. Therefore, it was concluded that the only heat treated electrospun PVA/AgNO3 fiber web was a good material as wound dressings because it had structural stability in moisture environment as well as excellent antimicrobial ability and, quick and continuous release of the effectiveness. POLYM. ENG. SCI., 47:43–49, 2007. © 2006 Society of Plastics Engineers