bluuebunny/crossref_metadata_2025 huggingface dataset:
Human herpesvirus type 8 infection in an area of Northern Italy with high incidence of classical Kaposi's sarcoma
Authors: Tanzi Elisabetta , Zappa Alessandra , Caramaschi Fausta , Amendola Antonella , Lasagna Donatella , Gatti Luciana , Ascoli Valeria , Rezza Giovanni , Zanetti Alessandro R.
Published: June 2005

Previous studies have reported a large variation in the incidence of classical Kaposi's sarcoma across different Districts of the province of Mantua (Northern Italy). To assess whether such differences might be explained by different anti‐HHV8 antibody prevalence, a serological study was conducted in 343 healthy elderly individuals resident in two adjacent Districts, at the highest and the lowest classical Kaposi's sarcoma incidence rate, respectively. Qualitative and quantitative determinations of IgG antibodies against both latent and lytic HHV‐8 antigens were performed by indirect immunofluorescence assay. The assay's sensitivity was studied in 26 patients with classical Kaposi's sarcoma. Overall, anti‐HHV8 antibodies were detected in 25 out of 26 patients (96%), confirming the high sensitivity of this assay. The prevalence of anti‐HHV‐8 antibodies was higher among individuals living in the District had a high incidence of classical Kaposi's sarcoma compared to those living in the District with low incidence (19.4% vs 9.8%, and 15.9% vs 8%; P < 0.05, for latent and lytic antibodies, respectively). Anti‐lytic antibody GMT was higher in people living in the District at high incidence rate compared to those of the other area (328.9 vs. 180.4; P < 0.01). A higher prevalence of HHV‐8 infection was found among persons living in municipalities surrounded by watercourses (OR 2.2, 95% CI: 1.10–4.32). In conclusion, variation in HHV‐8 prevalence appears to explain differences in the incidence rates of classical Kaposi's sarcoma observed in different areas of the province. J. Med. Virol. 76:571–575, 2005. © 2005 Wiley‐Liss, Inc.
The impact of high risk human papillomavirus testing in an inner London colposcopy clinic
Authors: Perrons Chris , Brink Nicola , Jalal Hamid , Watts Peter , Jelley Rosanne
Published: June 2005

This is an audit of a new technique to improve the colposcopy service. Samples were tested for high risk HPV DNA using Digene Hybrid Capture II. Sixty‐four percent of the sampled women under 30 had detectable high risk HPV DNA, decreasing to 44% in 30–39 year olds and to 27% in women over 40. High risk HPV prevalence increased with severity of cytology, although 22% with normal colposcopy had detectable high risk HPV. Of those women treated for cervical dysplasia, 83% had detectable high risk HPV prior to treatment, compared to only 32% afterwards. The audit has shown that high risk HPV testing has considerable discriminatory value. It has been integrated successfully into the service, particularly to manage low grade cervical abnormalities and to add valuable information following treatment for cervical dysplasia. Results need to be interpreted alongside colposcopy, cytology, and histology, and care must be taken in the interpretation of a single high risk HPV result. J. Med. Virol. 76:576–582, 2005. © 2005 Wiley‐Liss, Inc.
Norovirus contamination found in oysters worldwide
Authors: Cheng Peter K.C. , Wong Derek K.K. , Chung Thomas W.H. , Lim Wilina W.L.
Published: June 2005

Noroviruses (Norwalk‐like viruses) are recognized as major causes of acute gastroenteritis worldwide. Outbreaks of norovirus gastroenteritis are often associated with consumption of oysters. In this study, oysters imported into Hong Kong from 11 countries over a 3‐year period were screened by RT‐PCR. Overall, 53 out of 507 (10.5%) samples were positive for norovirus‐RNA, and a wide variety of strains were found. Two novel genetic clusters were detected, which could indicate novel human or animal norovirus strains. However, whether these two new clusters are of human or animal origin is not known. Thirteen outbreaks, in which oysters were implicated as the source of infection were investigated: Norovirus RNA sequences could be detected in oysters from six outbreaks, but only in one outbreak the strains isolated from patients and oysters matched (>98% homology). Therefore, RT‐PCR was of use in detecting norovirus contamination of oysters implicated in an outbreak, but was less useful in demonstrating an actual molecular epidemiological link with human cases. It was shown that contamination by noroviruses could be demonstrated in oysters worldwide, and therefore oysters may serve as an important vehicle for introducing novel norovirus strains. J. Med. Virol. 76:593–597, 2005. © 2005 Wiley‐Liss, Inc.
Evidence of the etiological predominance of norovirus in gastroenteritis outbreaks—emerging new‐variant and recombinant noroviruses in Hungary
Authors: Reuter Gábor , Krisztalovics Katalin , Vennema Harry , Koopmans Marion , Szűcs György
Published: June 2005

Between January 2001 and December 2003, stool specimens from 262 (45%) of 581 reported outbreaks of gastroenteritis were investigated for noroviruses in Hungary. Specimens collected from outbreaks of non‐bacterial gastroenteritis were examined by reverse‐transcription polymerase chain reaction and enzyme immunoassay. In 253 (97%) of 262 outbreaks, norovirus was detected and confirmed by sequencing in 211 (81%). Hospitals (35%), day care centers (30%), and elderly homes (27%) were the most common settings. Diversity and frequency of the genotypes changed over time but with predominance (95%) of genogroup (GG) II strains. Strains grouped into 11 genotypes including an epidemic spread of new‐variant GGII4 (Lordsdale virus) and a recently emerged group of natural recombinant strains (GGIIb/Hilversum polymerase) with four capsid types (Hawaii, Mexico, Snow Mountain, and Lordsdale). Clusters of epidemics including food‐borne outbreaks were detected. According to this study, noroviruses are the predominant etiological agents causing gastroenteritis outbreaks in Hungary. J. Med. Virol. 76:598–607, 2005. © 2005 Wiley‐Liss, Inc.
Prevalence and partial sequence analysis of human T cell lymphotropic virus type I in China
Authors: Wang Youchun , Li Xiouhua , Song Aijing , Zhang Chuntao , Chen Ying , Chen Changrong , Lin Yisheng , Shun Liping , Li Luilan , Liu Yanchun , Yang Jian , Yang Bowei , Tang Qiouping , Harrison Tim J.
Published: June 2005

A total of 145,293 serum samples were collected from volunteer blood donors in 13 provinces of China and tested for anti‐HTLV antibody using an ELISA licensed in China. Thirty were positive for anti‐HTLV by ELISA and 19 of those 30 samples were confirmed positive using a supplemental immunoblot assay. Anti‐HTLV‐I was detected only in samples from Fujian province (a Southern province) where the positivity rate was approximately 0.05%. The region encoding gp46 from 5 of the 19 antibody positive samples was amplified and sequenced. Sequence analysis indicated that these isolates belong to HTLV‐I genotype A. These data suggest that HTLV‐I is not endemic throughout China and the virus may be restricted to a particular region. J. Med. Virol. 76:613–618, 2005. © 2005 Wiley‐Liss, Inc.
Fitness of Japanese encephalitis virus to Neuro‐2a cells is determined by interactions of the viral envelope protein with highly sulfated glycosaminoglycans on the cell surface
Authors: Chiou Shyan‐Song , Liu Hsuan , Chuang Ching‐Kai , Lin Chiou‐Chun , Chen Wei‐June
Published: June 2005

Genetically different subpopulations were identified and purified from Japanese Encephalitis virus (JEV). Those with small plaques (SPs; <2 mm in diameter), derived from strains of T1P1, CJN, and CC27, were more competent than those with large plaques (LPs; >5 mm in diameter) when passaged in Neuro‐2a cells. Differences in amino acids between SPs and LPs from each strain were shown in the viral envelope (E) protein. The amino acid at E‐306 was Glu in LP but was substituted by Lys in SP in the T1P1 strain. A similar substitution occurred at E‐138 in the CJN strain. However, the amino acid was Asp in LP but was substituted by Asn in SP at E‐389 in the CC27 strain. All SPs were shown to have a higher affinity to the cellular membrane when compared to LPs, and this resulted in more‐efficient infection of Neuro‐2a cells, suggesting that the differential fitness of JEV variants to Neuro‐2a cells appeared in the early phase of infection. In addition, glycosaminoglycans (GAGs) on the surface of many mammalian cells have been demonstrated to be critical for infection by JEV, especially SP variants. The present results suggest that T1P1‐SP1 viruses infected Neuro‐2a cells more efficiently in spite of the sparse distribution of cell surface GAGs. We conclude that highly sulfated forms of GAGs expressed by Neuro‐2a cells play an important role in selecting JEV variants with specific mutations in the E glycoprotein. J. Med. Virol. 76:583–592, 2005. © 2005 Wiley‐Liss, Inc.
Derivation of macroscopic equations for individual cell‐based models: a formal approach
Authors: Bodnar M. , Velazquez J. J. L.
Published: June 2005

In this paper we review the theory of cells (particles) that evolve according to a dynamics determined by friction and that interact between themselves by means of suitable potentials. We derive by means of elementary arguments several macroscopic equations that describe the evolution of cell density. Some new results are also obtained—a formal derivation of a limit equation in the case of attractive potential as well as in the case of repulsive potential with a hard‐core part are presented. Finally we discuss the possible relevance of those results within the framework of individual cell‐based models. Several classes of potentials, including hard‐core, repulsive and potentials with attractive parts are discussed. The effect of noise terms in the equation is also considered. Copyright © 2005 John Wiley & Sons, Ltd.
A linearized heat‐conducting fluid and its quasi‐static approximation
Authors: Weinacht Richard J.
Published: June 2005

A linearized flow of a compressible inviscid heat‐conducting fluid is considered and a comparison is made with its coupled/quasi‐static approximation. Copyright © 2005 John Wiley & Sons, Ltd.
Boundary problems with meromorphic symbols in cylindrical domains
Authors: Harutyunyan G. , Schulze B.‐W.
Published: June 2005

We show relative index formulas for boundary value problems in cylindrical domains and Sobolev spaces with different weights at ±∞. The amplitude functions are meromorphic in the axial covariable and take values in the space of boundary value problems on the cross section of the cylinder. Copyright © 2005 John Wiley & Sons, Ltd.
Introduction: Novel therapies in developmental disabilities—Hope, reason, and evidence
Authors: Hyman Susan L. , Levy Susan E.
Published: June 2005

Complementary and alternative medicine (CAM) is used both alongside (complementary) and as a substitute for (alternative) conventional therapies. Although CAM use is reported to be high among children with typical development, reported rates for CAM use to address symptoms of children with developmental disabilities may be higher. Increased use in this population may relate to hope for amelioration of symptoms, concerns regarding side effects of conventional treatments, and a need on the part of families to participate in decision making regarding their child's care. Primary health care providers may find that the child's needs are best served when they maintain a dialogue with families to evaluate the evidence supporting novel therapies. Interventions need to be assessed in an evidence based fashion whether or not they are initally preceived as CAM. This issue of Mental Retardation and Developmental Disabilities Research Reviews contains reviews of CAM used to treat several developmental disabilities as well as some broader discussions related to the determinants of CAM use, current efforts to evaluate novel therapies, and how to consider the possibility of placebo effects. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:107–109.
The role of culture in families' treatment decisions for children with autism spectrum disorders
Authors: Mandell David S. , Novak Maytali
Published: June 2005

There is little information available about how and why parents of children with autism spectrum disorders (ASD) make decisions regarding which of the many available treatments to implement with their children. Given the lack of available information regarding treatment efficacy, it is likely that parents' beliefs about child development, interpretation of the symptoms of ASD, its etiology and course, and their experiences with the health system influence treatment decisions. This article addresses these issues within the context of cultural influences. We review the small body of existing literature regarding cultural influences on decisions regarding ASD and draw implications for the study and treatment of ASD from the larger body of literature on culture and other health conditions of childhood. In addition to examining the potential for differences in clinical presentation by culture and different experiences with the healthcare system, we use Kleinman's framework of questions for understanding the role of culture in the interpretation and treatment of ASD. These questions address interpretation of symptoms and beliefs about their cause, course, and treatment. Finally, we present specific language for clinicians to use in discussion with families with different cultural beliefs about the use of less traditional treatment strategies. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:110–115.
Novel treatments for autistic spectrum disorders
Authors: Levy Susan E. , Hyman Susan L.
Published: June 2005

In no area of developmental pediatric practice is there more controversy regarding the choice of treatment than related to children with autistic spectrum disorders (ASD). Complementary and alternative medical therapies (CAM) are often elected because they are perceived as treating the cause of symptoms rather than the symptoms themselves. CAM used for autism can be divided by proposed mechanism: immune modulation, gastrointestinal, supplements that affect neurotransmitter function, and nonbiologic intervention. Secretin as a therapy for autism is discussed as an example of how a clinical observation rapidly grew to a widespread treatment before well‐designed studies demonstrated absence of effect. The plausibility for behavioral effect was not substantiated by clinical studies. CAM used for treatment of autism is examined in terms of rationale, evidence of efficacy, side effects, and additional commentary. Families and clinicians need access to well‐designed clinical evidence to assist them in choice of therapies. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:131–142.
Complementary and alternative therapies for Down syndrome
Authors: Roizen Nancy J.
Published: June 2005

In their role as committed advocates, parents of children with Down syndrome have always sought alternative therapies, mainly to enhance cognitive function but also to improve their appearance. Nutritional supplements have been the most frequent type of complementary and alternative therapy used. Cell therapy, plastic surgery, hormonal therapy, and a host of other therapies such as massage therapy have been used. There is a lack of well‐designed scientific studies on the use of alternative therapies in individuals with Down syndrome. Antioxidants hold theoretical promise for treatment of the cognitive, immune, malignancy, and premature aging problems associated with Down syndrome. Medications for treatment of Alzheimer's disease may also result in benefit for the population of individuals with Down syndrome. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:149–155.
Old and new controversies in the alternative treatment of attention‐deficit hyperactivity disorder
Authors: Rojas Neal L. , Chan Eugenia
Published: June 2005

Use of complementary and alternative medicine (CAM) for treatment of attention‐deficit hyperactivity disorder (ADHD) has become widespread in both referral and primary care populations. We review the purported mechanism of action and available evidence for selected CAM therapies for ADHD. Enduring controversies, such as elimination of artificial food additives, colors, and/or preservatives; the effect of sugar on behavior in children; and the use of EEG biofeedback, have been well studied but lack support as effective sole treatments for ADHD. The initial evidence for some emerging CAM therapies, such as essential fatty acid supplementation, yoga, massage, homeopathy, and green outdoor spaces, suggests potential benefits as part of an overall ADHD treatment plan. More rigorously designed studies are needed to evaluate their effectiveness as single therapy for ADHD. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:116–130.
Placebo effects in developmental disabilities: Implications for research and practice
Authors: Sandler Adrian
Published: June 2005

Recent clinical trials of secretin in children with autism showed robust placebo effects and no benefit of secretin over placebo. This article explores the reasons for the observed placebo effects, focusing on the heightening of positive expectancy by media attention and by the sensory experiences associated with intravenous injections. Comparisons are drawn with research involving other novel treatments and other clinical populations of children with developmental disabilities and neurobehavioral disorders. Research regarding mechanisms of placebo effects is reviewed, including patient and clinician attributes, expectancy effects, participation effects, changes in caregiver behavior, and conditioning. New evidence regarding the biological basis of placebo effects is briefly presented. Since placebo effects are ubiquitous and may operate by a variety of mechanisms, research design is critical in designing clinical trials and in evaluating other outcomes research. Measurement issues important for research in developmental disabilities are emphasized. Ethical concerns have been raised regarding the use of placebo in clinical research, but current analysis suggests that placebo controls are necessary and defensible on ethical grounds, if certain conditions are met. The study of placebo effects (“placebology”) holds great promise as a new area of research in therapeutics. The author's research in the potential augmentation of stimulant effects in children with attention deficit/hyperactivity disorder (ADHD) by adding placebo in open label is briefly presented. The placebo has always been integral to the practice of medicine, but advances in scientific medicine and medical ethics have diminished the role and use of placebo in practice. An innovative approach to the ethical use of placebo is proposed. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:164–170.
Complementary and alternative therapies for cerebral palsy
Authors: Liptak Gregory S.
Published: June 2005

The optimal practice of medicine includes integrating individual clinical expertise with the best available clinical evidence from systematic research. This article reviews nine treatment modalities used for children who have cerebral palsy (CP), including hyperbaric oxygen, the Adeli Suit, patterning, electrical stimulation, conductive education, equine‐assisted therapy, craniosacral therapy, Feldenkrais therapy, and acupuncture. Unfortunately, these modalities have different degrees of published evidence to support or refute their effectiveness. Uncontrolled and controlled trials of hippotherapy have shown beneficial effects on body structures and functioning. Studies of acupuncture are promising, but more studies are required before specific recommendations can be made. Most studies of patterning have been negative and its use cannot be recommended. However, for the other interventions, such as hyperbaric oxygen, more evidence is required before recommendations can be made. The individual with CP and his or her family have a right to full disclosure of all possible treatment options and whatever knowledge currently is available regarding these therapies. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:156–163.
Occupational therapy using a sensory integrative approach for children with developmental disabilities
Authors: Schaaf Roseann C. , Miller Lucy Jane
Published: June 2005

This article provides an introduction and overview of sensory integration theory as it is used in occupational therapy practice for children with developmental disabilities. This review of the theoretical tenets of the theory, its historical foundations, and early research provides the reader with a basis for exploring current uses and applications. The key principles of the sensory integrative approach, including concepts such as “the just right challenge” and “the adaptive response” as conceptualized by A. Jean Ayres, the theory's founder, are presented to familiarize the reader with the approach. The state of research in this area is presented, including studies underway to further delineate the subtypes of sensory integrative dysfunction, the neurobiological mechanisms of poor sensory processing, advances in theory development, and the development of a fidelity measure for use in intervention studies. Finally, this article reviews the current state of the evidence to support this approach and suggests that consensual knowledge and empirical research are needed to further elucidate the theory and its utility for a variety of children with developmental disabilities. This is especially critical given the public pressure by parents of children with autism and other developmental disabilities to obtain services and who have anecdotally noted the utility of sensory integration therapy for helping their children function more independently. Key limiting factors to research include lack of funding, paucity of doctorate trained clinicians and researchers in occupational therapy, and the inherent heterogeneity of the population of children affected by sensory integrative dysfunction. A call to action for occupational therapy researchers, funding agencies, and other professions is made to support ongoing efforts and to develop initiatives that will lead to better diagnoses and effective intervention for sensory integrative dysfunction, which will improve the lives of children and their families. © 2005 Wiley‐Liss, Inc. MRDD Research Reviews 2005;11:143–148.
A new minimally invasive procedure for pudendal nerve stimulation to treat neurogenic bladder: Description of the method and preliminary data
Authors: Spinelli Michele , Malaguti Silvia , Giardiello Gianluca , Lazzeri Massimo , Tarantola Jessica , Hombergh Ubi Van Den
Published: June 2005

Aims

Pudendal nerve stimulation has beneficial effects on numerous pelvic floor function impairments such as urinary and/or fecal incontinence, retention, and constipation. In preceding literature the implant technique required a fairly complex and invasive surgery, although recent advances with percutaneous placement of the lead through an introducer have made the procedure much less invasive. We performed staged procedure similar to that of sacral neuromodulation (SNM) to place tined lead near the pudendal nerve, using neurophysiological guidance that allowed accurate pudendal nerve stimulation through either perineal or posterior approach. We have named this approach chronic pudendal nerve stimulation (CPNS).

Methods

Fifteen neurogenic patients (eight male, seven female) with symptoms of urge incontinence due to neurogenic overactive bladder underwent CPNS. All patients had complete neurophysiological and urodynamic evaluation at baseline and follow‐up and were asked to complete voiding and bowel diary for 7 days.

Results

During screening, average number of incontinent episodes per day decreased from 7 ± 3.3 to 2.6 ± 3.3 (P < 0.02, paired t‐test). Eight patients became continent, two improved by more than 88% (from 9 to 1 daily incontinence episode) and two patients reduced the number of incontinence episodes by 50%. The implantable pulse generator (IPG) was subsequently implanted in those 12 patients. Three patients without improvement did not continue to second stage. In implanted patients with 6 months follow‐up, urodynamic evaluation showed an objective improvement in the maximum cystometric capacity which increased from 153.3 ± 49.9 to 331.4 ± 110.7 ml (P < 0.01, paired t‐test). The maximum pressure decreased from 66 ± 24.3 to 36.8 ± 35.9 cmH2O (P = 0.059, paired t‐test). Eight patients reported significant improvement in bowel function.

Conclusion

Chronic pundedal nerve stimulation is feasible. Neurophysiological guidance is mandatory to place the lead near the pudendal nerve either using perineal or posterior approach. Further studies must be carried out to identify the best stimulation parameters and to verify the long term results. Neurourol. Urodynam. 24:305–309, 2005. © 2005 Wiley‐Liss, Inc.
Improved surgical outcome by modification of porcine dermal collagen implant in abdominal wall reconstruction in rats
Authors: Zheng Fang , Verbeken Eric , de Ridder Dirk , Deprest Jan
Published: June 2005

Aim

We earlier showed in rats that fascial repair with Pelvicol, a porcine dermal collagen implant, was associated with a lesser inflammatory response but lower tensile strength in the early postoperative period as compared to Prolene. Herein we wanted to evaluate whether creation of pores in Pelvicol, facilitating ingrowth of fibrous tissue and vessels, would result in a higher tensile strength at d30 without compromising longer term results.

Methods

First tensile strength of Pelvicol modified with different pore sizes was evaluated ex vivo. In a second step, Pelvicol implants with pores were used to cover full‐thickness abdominal wall defects in 36 rats. Implants were either Pelvicol (non‐porous) or with pores of Φ : 0.7, 1.2, or 2.0 mm (n = 6 each). Animals were sacrificed on d30 and 90 to evaluate the presence of herniation, infection, adhesions, change in thickness and tensile strength. Histopathology was performed to assess inflammatory response and collagen deposition. Data were compared to available data on Prolene implanted animals at same time points.

Results

Pelvicol with pore diameter of 2.5 mm was significantly weaker ex vivo. Animals repaired with non‐porous material did develop seroma (2/6) or clinical infection (1/6) whereas none in the other groups did. There was a trend for increasing tensile strength at 30 d with increasing pore diameter, being significant in the 2.0‐mm pore size group. This difference disappeared by 90 d, where all materials were equally strong as Prolene. The foreign body reaction was less intense in a pore‐size dependent manner, with more abundant neo‐vascularization and collagen deposition passing through the pores.

Conclusion

Creation of pores in Pelvicol promotes neo‐vascularization, collagen deposition, and fibrous tissue ingrowth, and at pore size 2.0 mm tensile strength was increased at d30 whereafter all materials had comparable strength. Neurourol. Urodynam. 24:362–368, 2005. © 2005 Wiley‐Liss, Inc.
Optimum shapes of tire‐treads for avoiding lateral slippage between tires and roads
Authors: Reaz Ahmed S. , Deb Nath S. K. , Wahhaj Uddin M.
Published: June 2005

Optimum design of tire‐tread sections is an important practical issue. However, useful study of the problem that can suggest a reliable guideline for determining the optimum tread sections had hardly been made in the past. The present paper describes a new analysis of the state of stresses in tire‐tread sections in contact with the road surface, taking special care of the boundary conditions. Based on the analysis, a method is proposed to determine the optimum tread shapes for avoiding lateral slippage between tires and roads. The displacement potential function formulation, an ideal mathematical model for the practical stress problems, has been used in conjunction with finite‐difference method of solution. For the present analysis, lateral slipping in absence of frictional resistance as well as the no‐slip conditions of the tire‐tread contact surface have been considered along with a large number of tread aspect ratios. The present computational approach proves to be a powerful tool for determining the optimum tread shapes for avoiding the lateral slippage of tire‐treads. Copyright © 2005 John Wiley & Sons, Ltd.
The least‐squares meshfree method for elasto‐plasticity and its application to metal forming analysis
Authors: Kwon Kie‐Chan , Park Sang‐Hoon , Youn Sung‐Kie
Published: June 2005

A new meshfree method for the analysis of elasto‐plastic deformation is presented. The method is based on the proposed first‐order least‐squares formulation for elasto‐plasticity and the moving least‐squares approximation. The least‐squares formulation for classical elasto‐plasticity and its extension to an incrementally objective formulation for finite deformation are proposed. In the formulation, equilibrium equation and flow rule are enforced in least‐squares sense, i.e. their squared residuals are minimized, and hardening law and loading/unloading condition are enforced pointwise at each integration point. The closest point projection method for the integration of rate‐form constitutive equation is inherently involved in the formulation, and thus the radial‐return mapping algorithm is not performed explicitly. The proposed formulation is a mixed‐type method since the residuals are represented in a form of first‐order differential system using displacement and stress components as nodal unknowns. Also the penalty schemes for the enforcement of boundary and frictional contact conditions are devised and the reshaping of nodal supports is introduced to avoid the difficulties due to the severe local deformation near contact interface. The proposed method does not employ structure of extrinsic cells for any purpose. Through some numerical examples of metal forming processes, the validity and effectiveness of the method are discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Spectral smoothed boundary methods: The role of external boundary conditions
Authors: Bueno‐Orovio Alfonso , Pérez‐García Víctor M.
Published: June 2005

The spectral smoothed boundary method (SSBM) is a recently proposed numerical method to approximate the solution of partial differential equations in irregular domains with no‐flux boundary conditions by means of Fourier spectral methods. In this article we explore the robustness and accuracy of the scheme under variations of the artificial boundary conditions that must be imposed on the boundary of the enlarged domain in which the problem is solved. As a test model, we present quantitative numerical results based on a problem of propagation of waves of electrical activity in cardiac tissue for which the method is relevant. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
Effect of coagulant temperature and composition on surface morphology and mass transfer properties of cellulose acetate hollow fiber membranes
Authors: Chou Wen‐Li , Yang Ming‐Chien
Published: June 2005

Cellulose acetate (CA) hollow fibers were spun via the dry‐jet wet spinning technique under various external coagulant compositions and temperatures. The surface morphology of the resulting hollow fiber was examined using field emission scanning electron microscopy (FESEM) and tapping mode atomic force microscopy (TMAFM). The pure water permeability (PWP) and the retention of dextran of the hollow fiber were also measured. The results showed that both the temperature and composition can affect greatly the surface morphology and hence the permeation performance of hollow fiber membranes when the temperature was over 55°C and the dimethyl formamide (DMF) content was higher than 15%. The on‐line draw ratio increased with the coagulant temperature and DMF content (in the range of 0 to 10%) in the external coagulant. The ultimate tensile strength also increased when the fibers were coagulated in 5–10% DMF and at 70°C. The PWP increased with the DMF content in the coagulant and the coagulant temperature. The retention of dextran decreased with the increase of the DMF content in the coagulant and the coagulant temperature. Copyright © 2005 John Wiley & Sons, Ltd.
Stable second‐order NLO semi‐IPN system based on bipyridine‐containing polyimide and alkoxysilane dye
Authors: Kuo Wen‐Jang , Chang Ming‐Chun , Juang Tzong‐Yuan , Chen Chih‐Ping , Chen Chin‐Ti , Chang Huey‐Ling , Jeng Ru‐Jong
Published: June 2005

An organosoluble polyimide based on bipyridyl moiety and an alkoxysilane dye have been developed for second‐order non‐linear optics (NLOs). This bipyridine‐containing polyimide exhibits a glass transition temperature of 254°C and a degradation temperature of 400°C. An NLO‐active semi‐interpenetrating network (IPN) system was prepared by blending the polyimide with the alkoxysilane dye via in situ sol‐gel process of alkoxysilane. The selection of this bipyridine‐containing polyimide as the polymeric matrices provides improved solubility and thermal stability, and most importantly enhanced intermolecular interactions. No aggregation of the NLO chromophores in the polyimide matrices was observed through morphology and NLO studies. Under the limitation of chromophore degradation at elevated temperatures, the pristine poled/cured alkoxysilane dye exhibits poorer long‐term stability. By introducing the polyimide upon a silica network by the semi‐IPN system, randomization of the oriented chromophores can be effectively suppressed. Using in situ contact poling, the r33 coefficients of 2.2–17.0 pm/V were obtained for the optically clear semi‐IPN NLO materials. Excellent temporal stability (100°C) was also achieved for these semi‐IPN materials. Copyright © 2005 John Wiley & Sons, Ltd.
Extrudate swell and flow analysis of polystyrene melt flowing in an electro‐magnetized die in a single screw extruder
Authors: Sombatsompop Narongrit , Intawong Naret
Published: June 2005

An electro‐magnetized capillary die via a parallel co‐extrusion technique was used to study the changes in the overall and radial extrudate swell ratio of polystyrene (PS) melt flowing in a single screw extruder. The effects of magnetic flux density, wall shear rate (screw rotating speed) and die temperature were studied. The results suggested that, in the case of non‐magnetic die the average overall swell ratio of the melt ranged from 1.25 to 1.55. The swelling ratio increased with increasing wall shear rate up to 8.5 sec−1 and then decreased at 17.1 sec−1. Increasing die temperature caused a reduction of extrudate swell ratio. The changes in extrudate swell ratio can be explained using the simultaneously measured velocity profiles during the flow in the die, and the swell ratio decreased with increasing radial position. Melt contraction of the melt layer near the die wall was observed. The die temperature was found to have no effect on the change of the radial extrudate swell profiles. When an electro‐magnetized die was used, the average overall swell ratio was found to increase with increasing magnetic flux density to a maximum value and then decreased at higher flux densities. The magnetic flux density of the maximum swell was changed by the wall shear rate. It was associated with a balance of elastic and magnetic energies during the flow. The magnetic energy was thought to have a pronounced effect on the swell ratio at low shear rate and low die temperature. Considering the radial position, the highest swell ratio occurred at the duct center, in the range 2.4–3.3. There was no extrudate contraction of the melt layer near the die wall. Copyright © 2005 John Wiley & Sons, Ltd.
Biodegradable shape‐memory polymer—polylactide‐co‐poly(glycolide‐co‐caprolactone) multiblock copolymer
Authors: Min Changchun , Cui Wenjin , Bei Jianzhong , Wang Shenguo
Published: June 2005

In this study, biodegradable shape‐memory polymers—polylactide‐co‐poly(glycolide‐co‐caprolactone) multiblock (PLAGC) copolymers—were synthesized by the coupling reaction of both macrodiols of polylactide (PLLA‐diol) and poly(glycolide‐co‐caprolactone) (PGC‐diol) in the presence of 1,6‐hexanediisocyanate as coupling agent. The copolymers formed were found to be thermoplastic and easily soluble in common solvents. The compositions of the copolymers were determined by 1H‐NMR and the influences of segment lengths and contents of both macrodiols on the properties of the PLAGC copolymers were investigated. It was found that the copolymers had adjustable mechanical properties which depended on contents and segment lengths of both macrodiols. The copolymers showed such good shape‐memory properties that the strain fixity rate (Rf) and the strain recovery rate (Rr) exceed 90%. By means of adjusting the compositions of the copolymers, PLAGC copolymers with transition temperatures around 45°C could be obtained. The degradation rate determination showed that the PLAGC copolymers have fast degradation rates, the mechanical strengths of the PLAGC copolymers would be completely lost within 1–2 months depending on molecular weights and contents of the both segments of PLLA and PGC. Copyright © 2005 John Wiley & Sons, Ltd.
The preparation of nano‐scope chitosan‐oligomer copper complexes and their interaction with DNA
Authors: Wang Rong‐Min , He Nai‐Pu , He Yu‐Feng , Xie Yun‐Tao , Wang Yun‐Pu , Tsuchida Eishun
Published: June 2005

Water‐soluble low molecular weight chitosan of nanometer level and its copper complexes were prepared, and characterized by IR spectra, elemental analysis and gel permeation chromatography (GPC). The modes and mechanism of these copper complexes interaction with DNA were studied by a fluorescent probe method and electrophoresis analysis. It is suggested that there are electrostatic and intercalation modes of copper complexes interacting with DNA. At first, the cationic complex electrostaticly binds to the negatively charged phosphate backbone of DNA, and then a portion of the complex intercalates between the base pairs on the DNA duplex strand. Copyright © 2005 John Wiley & Sons, Ltd.
Preparation of porous polylactide microspheres by emulsion‐solvent evaporation based on solution induced phase separation
Authors: Hong Yi , Gao Changyou , Shi Yanchao , Shen Jiacong
Published: June 2005

Porous polylactide (PLA) microspheres were fabricated by an emulsion‐solvent evaporation method based on solution induced phase separation. Scanning electron microscopy (SEM) observations confirmed the porous structure of the microspheres with good connectivity. The pore size was in the range of decade micrometers. Besides large cavities as similarly existed on non‐porous microspheres, small pores were found on surfaces of the porous microspheres. The apparent density of the porous microspheres was much smaller than that of non‐porous microspheres. Fabrication conditions such as stirring rate, good solvent/non‐solvent ratio, PLA concentration and dispersant (polyvinyl alcohol, PVA) concentration had an important influence on both the particle size and size distribution and the pore size within the microspheres. A larger pore size was achieved at a slower stirring rate, lower good solvent/non‐solvent ratio or lower PLA concentration due to longer coalescence time. Copyright © 2005 John Wiley & Sons, Ltd.
The preparation and characterization of silver‐loading cellulose acetate hollow fiber membrane for water treatment
Authors: Chou Wen‐Li , Yu Da‐Guang , Yang Ming‐Chien
Published: June 2005

Silver‐loading asymmetric cellulose acetate (CA) hollow fiber membrane was spun via the dry jet‐wet spinning technique. The spinning solution was prepared by dissolving AgNO3 and CA in N,N‐dimethylformamide (DMF). The silver ions were reduced in the spinning dope into silver nano‐particles. The morphology of the resulting hollow fibers was examined using a scanning electron microscope and the silver content in the fiber was measured using an inductively coupled plasma atomic emission spectrometer. The antibacterial activities were evaluated. These hollow fibers had a sponge‐like structure and dense inner and outer surfaces. At a 50 k magnification, the pore on the skin layer was not observable, while the nodule size was smaller than 10 nm. The residual silver content of as‐spun hollow fiber was about 60% of the original silver added in the polymer solution. After immersing in water bath for 180 days, the silver content in the bulk of the hollow fibers decreased to 60% and the silver content on the surface reduced to 10%, yet still showed antibacterial activity against Escherichia coli and Staphylococcus aureus. After permeating with water for 5 days, the silver content in the hollow fibers decreased, and did not show antibacterial activity against E. coli and S. aureus. Thus, silver content must be periodically replenished after permeation. The proper range of AgNO3 in the spinning solution for CA hollow fiber should be about 100–1000 ppm. Copyright © 2005 John Wiley & Sons, Ltd.
Solvent‐induced reversible color changes in block copolymer films and new locking method of structural colors
Authors: Ishizu Koji , Yasuda Michio , Sato Yumi , Tamura Toru
Published: June 2005

The well‐defined polystyrene‐block‐poly(4‐vinylpyridine) [PS‐block‐P4VP (SV1); lamellar morphology] and polyisoprene‐block‐poly(α‐methyl styrene) [PI‐block‐PMS (IMS1); PI spherical morphology] diblock copolymers were prepared by sequential anionic polymerization techniques. The segregated chains in the P4VP lamellar layers of the SV1 film (PS lamellae: 41 nm; P4VP lamellae: 51 nm) were crosslinked with 1,4‐dibromobutane. This crosslinked film was insoluble in organic solvents such as benzene and chloroform (CHCl3) and exhibited various structural colors under the swollen state. The IMS1 film (body‐centered cubic lattice, diameter of PI spheres: 53 nm) was soaked in the mixture of CHCl3/hexane (1 : 10, v/v). This solvent system resulted in the swelling of PI spherical domains. The transmitted and reflected light color through the swollen film changed to a deep blue. Such color changes were reversible upon swelling in solvent and evaporation of the solvent. Subsequently, photofunctional diethyldithiocarbamate (DC) groups were introduced into the PS block of the parent block copolymer IMS1 by means of polymer reactions. The locking of the cubic lattice was performed with living radical graft copolymerization from DC groups of swollen as‐cast film in methyl methacrylate (MMA) under UV irradiation. The locking of structural colors such as blue and green was also achieved, varying the content of poly(methyl methacrylate) (PMMA) grafted chains. Copyright © 2005 John Wiley & Sons, Ltd.
Structure and redox properties of electropolymerized film obtained from iron meso‐tetrakis(3‐thienyl)porphyrin
Authors: Yuasa Makoto , Oyaizu Kenichi , Yamaguchi Aritomo , Ishikawa Masuhide , Eguchi Katsuya , Kobayashi Tomohiro , Toyoda Yuujiro , Tsutsui Satoshi
Published: June 2005

Oxidative polymerization of bromoiron(III) meso‐tetrakis(3‐thienyl)porphyrin gave a novel polymeric porphyrin complex randomly crosslinked at the 2,5‐positions of the peripheral thienyl groups. The electrical semiconductivity of ca. 10−5 S/cm after I2 doping indicated that the polymer had a π‐conjugated structure with a moderate delocalization of π electrons over the thienylporphyrin units. PM3 calculations for free‐base models revealed that HOCO (the highest occupied crystal orbital) band width was reduced by introduction of the porphyrin moieties into the thienylene backbone and yet low HOCO‐LUCO (the lowest unoccupied crystal orbital) gap was maintained, which accounted for the relatively low electrical conductivity of the porphyrin polymer. The modified electrode prepared by electropolymerization was redox‐active due to the presence of iron(II/III) couple and the semiconductivity of the film, which served as a novel non‐enzymatic electrochemical sensor for superoxide anion radical based on the facile electrocatalytic oxidation of the superoxide. Copyright © 2005 John Wiley & Sons, Ltd.
Electrospinning of methacrylate‐based copolymers: Effects of solution concentration and applied electrical potential on morphological appearance of as‐spun fibers
Authors: Pornsopone Varaporn , Supaphol Pitt , Rangkupan Ratthapol , Tantayanon Supawan
Published: June 2005

Three methacrylate‐based copolymers [i.e., poly(methacrylic acid‐co‐methyl methacrylate), poly(ethyl acrylate‐co‐methyl methacrylate‐co‐trimethyl‐ammonioethyl methacrylate chloride), and poly(butyl methacrylate–co‐(2‐dimethylaminoethyl) methacrylate‐co‐methyl methacrylate)] were successfully electrospun into fibers using ethanol as the solvent. For a given applied electrical potential, increasing the concentration of the spinning solutions caused the morphology of the as‐spun products to change from discrete droplets to a combination of beaded and smooth fibers and finally to completely smooth fibers. For a given spinning solution having a low concentration, increasing the applied electrical potential increased the electro‐spinnability of the spinning solution. The average diameters for all of the as‐spun fibers were found to range between about 0.2 and 5.5 μm. Generally, for a given applied potential, the average fiber diameter increased with increasing concentration of the spinning solutions, and for a given solution concentration the average fiber diameter increased with increasing applied electrical potential. POLYM. ENG. SCI., 45:1073–1080, 2005. © 2005 Society of Plastics Engineers
Sulfonated poly(ether ketone ketone) ionomers as proton exchange membranes
Authors: Swier Steven , Chun Yong Sung , Gasa Jeffrey , Shaw Montgomery T. , Weiss R.A.
Published: June 2005

Sulfonated poly(ether ketone ketone) ionomers (SPEKK) with ion‐exchange capacities (IEC) between 0.2 and 3.4 meq/g were prepared by sulfonating PEKK with a mixture of concentrated and fuming sulfuric acids. Sulfonation occurs only on the phenyl rings attached to ether and ketone groups. The glass transition temperature of the dry SPEKK ionomers increased linearly with increasing IEC, and the ionomers were thermally stable to ∼250°C, above which desulfonation occurred. Water‐swollen ionomers exhibited microphase separated morphologies, and the average correlation length determined by small angle X‐ray scattering increased with increasing IEC. The proton conductivity of hydrated SPEKK membranes measured by impedance spectroscopy ranged from ∼10–3 to 10–1 S/cm as the IEC increased from ∼1.0 to 2.4 meq/g. Single cell performance curves on membrane‐electrode assemblies (MEA) indicated that the SPEKK membranes approached the performance of Nafion™ for an IEC of 2 meq/g. POLYM. ENG. SCI., 45:1081–1091, 2005. © 2005 Society of Plastics Engineers
Rheology studies of polyethylene/chemical blowing agent solutions within an injection molding machine
Authors: Qin X. , Thompson M.R. , Hrymak A.N. , Torres A.
Published: June 2005

An in‐line capillary rheometer nozzle equipped to a conventional reciprocating 55‐ton injection molding machine was used to study the viscosity of single phase low density polyethylene (LDPE)/chemical blowing agent (CBA) solutions under high shear rate in the concentration range of 0 to 5 wt%. The steady shear viscosity of LDPE with endothermic and exothermic chemical blowing agents was measured for shear rates ranging from 170 to 200,000 s−1 and under pressure conditions up to 36 MPa. Pressure‐volume‐temperature (pvT) measurements were determined to account for the pressure effects and the changes of the free volume during processing. The viscosity reduction of the polymer‐CBA solution was found to be dependent on the concentration of the chemical blowing agent and melt pressure. A model based on a simplified Cross‐Carreau model, incorporating the pvT behavior of LDPE, and the free volume concept was proposed to estimate the viscosity reduction resulting from the addition of a chemical blowing agent. The model employs a scaling method based on concentration‐dependent and pressure‐dependent shift factors to collapse the viscosity measurement to a master curve at each temperature. POLYM. ENG. SCI., 45:1108–1118, 2005. © 2005 Society of Plastics Engineers